Yingbo Na - Academia.edu (original) (raw)

Papers by Yingbo Na

Canadian Medical Association Journal, Apr 11, 2021

eratinocyte carcinoma (also called nonmelanoma skin cancer) includes basal and squamous cell carc... more eratinocyte carcinoma (also called nonmelanoma skin cancer) includes basal and squamous cell carcinoma, the 2 most common malignancies in North America. 1,2 More than 76 000 and 5.4 million cases are diagnosed annually in Canada and the United States, respectively. 1,2 Melanoma is the fifth most common malignancy in the US, with 83 362 annual cases, 10 000 deaths and incidence rates rising by 10% between 2005 and 2015. 3-5 It is estimated that there were 8000 new melanoma cases and 1300 related deaths in Canada in 2020. 6 Given the high and increasing population burden of these skin cancers, identifying modifiable risk factors is important. 7,8 Ultraviolet (UV) radiation exposure is the most important environmental risk factor for skin cancer. 9,10 Medication-induced phototoxicity, in which medications interact with UV radiation to cause cellular damage in the skin, may increase the carcinogenic potential of sun exposure. 11 Antihypertensive medications are used by about 1 in 5 adults, 12 and thiazide diuretics, calcium channel blockers, β-blockers, angiotensin II receptor blockers (ARBs) and angiotensin-converting enzyme (ACE) inhibitors have all been reported to be phototoxic. 11,13 Hydrochlorothiazide is first-line pharmacotherapy for hypertension 14 and is considered the most phototoxic anti hypertensive medication. 11,13 It has been implicated in increasing the risk of keratinocyte carcinoma, with 2 recent case-control studies 15,16 prompting Health Canada, the European Medicines Agency and the US Food and Drug Administration to issue warnings regarding prolonged use. 17-19 Weaker associations have been reported between thiazides and melanoma, 20 and there is conflicting evidence on the association between other antihypertensive classes and skin cancer. 21 To determine whether exposure to thiazides or other antihypertensive medications is associated with skin cancer, we conducted a population-based inception cohort study.

Peritoneal Dialysis International, May 1, 2015

A significant proportion of peritoneal dialysis (PD) patients receive an initial period of hemodi... more A significant proportion of peritoneal dialysis (PD) patients receive an initial period of hemodialysis (HD) before transitioning to PD ("PD-switch"). We sought to better understand the risks of PD technique failure (TF) and mortality for those patients compared with patients starting with PD as their first dialysis modality ("PD-first"). Using Canadian Organ Replacement Register data, we compared the risk of PD TF between PD-first and PD-switch patients within the first year after HD initiation. In a secondary analysis, the PD-switch patients were stratified into three groups based on timing of the switch from initial HD to PD as follows: 0 - 90 days, 91 - 180 days, and 181 - 365 days. Each group was compared with PD-first patients for risk of PD TF and death. Between 2001 and 2010, 9404 patients initiated PD as their first renal replacement therapy, and 3757 switched from HD to PD. After multivariable adjustment, the risk of PD TF was higher among PD-switch patients than among PD-first patients [adjusted hazard ratio (AHR): 1.37; 95% confidence interval (CI): 1.26 to 1.49], particularly within the first year after the switch from HD to PD (AHR: 1.51; 95% CI: 1.36 to 1.68). There was no association between time on HD within the first year and subsequent risk of PD TF. For all the stratified PD-switch groups, death rates were higher than those for PD-first patients. Compared with patients who start renal replacement therapy with PD, those who transfer from HD to PD within the first year on dialysis experience higher rates of PD TF and death, with the highest risk being observed in the initial year after the switch to PD.

American journal of kidney diseases : the official journal of the National Kidney Foundation, Jan 16, 2015

While central venous catheter (CVC) use has expanded home hemodialysis (HHD) eligibility to many ... more While central venous catheter (CVC) use has expanded home hemodialysis (HHD) eligibility to many patients who may be unable to self-cannulate an arteriovenous (AV) access, the association between CVC use and mortality has not been directly examined among HHD patients. Registry-based retrospective observational cohort study. Incident HHD patients in The Canadian Organ Replacement Register who had information for vascular access type (CVC vs AV access) within the first year of HHD therapy initiation. Use of a CVC versus an AV access (AV fistula or graft) within the first year of HHD therapy initiation. The composite of all-cause mortality and technique failure (long-term transfer to an alternate dialysis modality). A Cox proportional hazards model was used to evaluate the adjusted composite outcome and each outcome separately. 1,869 patients initiated HHD therapy in Canada in 1996 to 2012, of whom 1,217 had an access type recorded within the first year of HHD therapy initiation. Compa...

Peritoneal Dialysis International, 2013

A significant proportion of peritoneal dialysis (PD) patients receive an initial period of hemodi... more A significant proportion of peritoneal dialysis (PD) patients receive an initial period of hemodialysis (HD) before transitioning to PD ("PD-switch"). We sought to better understand the risks of PD technique failure (TF) and mortality for those patients compared with patients starting with PD as their first dialysis modality ("PD-first"). Using Canadian Organ Replacement Register data, we compared the risk of PD TF between PD-first and PD-switch patients within the first year after HD initiation. In a secondary analysis, the PD-switch patients were stratified into three groups based on timing of the switch from initial HD to PD as follows: 0 - 90 days, 91 - 180 days, and 181 - 365 days. Each group was compared with PD-first patients for risk of PD TF and death. Between 2001 and 2010, 9404 patients initiated PD as their first renal replacement therapy, and 3757 switched from HD to PD. After multivariable adjustment, the risk of PD TF was higher among PD-switch patients than among PD-first patients [adjusted hazard ratio (AHR): 1.37; 95% confidence interval (CI): 1.26 to 1.49], particularly within the first year after the switch from HD to PD (AHR: 1.51; 95% CI: 1.36 to 1.68). There was no association between time on HD within the first year and subsequent risk of PD TF. For all the stratified PD-switch groups, death rates were higher than those for PD-first patients. Compared with patients who start renal replacement therapy with PD, those who transfer from HD to PD within the first year on dialysis experience higher rates of PD TF and death, with the highest risk being observed in the initial year after the switch to PD.

Kidney International, 2005

The relationship between low hematocrit and contrast-induced nephropathy has not been investigate... more The relationship between low hematocrit and contrast-induced nephropathy has not been investigated. Of 6,773 consecutive patients treated with percutaneous coronary intervention, contrast-induced nephropathy (an increase of >/=25% or >/=0.5 mg/dL in preprocedure serum creatinine, at 48 hours postprocedure) occurred in 942 (13.9%) patients. Rates of contrast-induced nephropathy steadily increased as baseline hematocrit quintile decreased (from 10.3% in the highest quintile to 23.3% in the lowest quintile) (chi(2) for trend, P < 0.0001). Stratification by baseline estimated glomerular filtration rate (eGFR) and baseline hematocrit showed that the rates of contrast-induced nephropathy were the highest (28.8%) in patients who had the lowest level for both baseline eGFR and hematocrit. Patients with the lowest eGFR but relatively high baseline hematocrit values had remarkably lower rates of contrast-induced nephropathy (15.8%, 12.3%, 17.1%, and 15.4% in 2nd, 3rd, 4th, and 5th quintiles of baseline hematocrit, respectively) (P < 0.0001). The rates of contrast-induced nephropathy increased with increment in change in hematocrit. Patients in the lowest quintile of baseline hematocrit with absolute hematocrit drop >5.9% had almost doubled rates of contrast-induced nephropathy compared with patients with hematocrit change <3.4% (38.1% vs. 18.8%, respectively) (P < 0.0001). By multivariate analysis, lower baseline hematocrit was an…

Journal of the American Society of Nephrology, 2011

Several comparisons of peritoneal dialysis (PD) and hemodialysis (HD) in incident patients with E... more Several comparisons of peritoneal dialysis (PD) and hemodialysis (HD) in incident patients with ESRD demonstrate superior survival in PD-treated patients within the first 1 to 2 years. These survival differences may be due to higher HD-related mortality as a result of high rates of incident central venous catheter (CVC) use or due to an initial survival advantage conferred by PD. We compared the survival of incident PD patients with those who initiated HD with a CVC (HD-CVC) or with a functional arteriovenous fistula or arteriovenous graft (HD-AVF/AVG). We used multivariable piece-wise exponential nonproportional and proportional hazards models to evaluate early (1 year) mortality as well as overall mortality during the period of observation using an intention-to-treat approach. We identified 40,526 incident adult dialysis patients from the Canadian Organ Replacement Register (2001Register ( to 2008. Compared with the 7412 PD patients, 1-year mortality was similar for the 6663 HD-AVF/AVG patients but was 80% higher for the 24,437 HD-CVC patients (adjusted HR, 1.8; 95% confidence intervals [CI], 1.6 to 1.9). During the entire period of follow-up, HD-AVF/AVG patients had a lower risk for death, and HD-CVC patients had a higher risk for death compared with patients on PD. In conclusion, the use of CVCs in incident HD patients largely accounts for the early survival benefit seen with PD.

Journal of the American College of Cardiology, 2006

The objectives of the study were to evaluate the effect of angiographic follow-up on revasculariz... more The objectives of the study were to evaluate the effect of angiographic follow-up on revascularization rates in the TAXUS-IV trial and to determine whether the relative benefit of paclitaxel-eluting stent implantation compared with bare metal stent implantation was modified by angiographic follow-up. BACKGROUND Although several clinical trials have demonstrated that drug-eluting stents (DES) reduce restenosis compared with bare-metal stents (BMS), virtually all of these studies have incorporated angiographic follow-up.

Journal of the American College of Cardiology, 2008

We sought to validate 4 angiographic measures as potential surrogates for clinical restenosis (ta... more We sought to validate 4 angiographic measures as potential surrogates for clinical restenosis (target lesion revascularization [TLR]) after stent implantation. Given the low revascularization rates with drug-eluting stents (DES), an angiographic surrogate of TLR is desirable to reduce the sample size required to demonstrate efficacy in future trials of antirestenosis devices. We evaluated 4 potential angiographic measures (late loss [LL] and percent diameter stenosis [%DS], both in-stent and in-segment) as a surrogate for TLR at 1 year. From 11 multicenter, prospective randomized stent trials, 9 comparing DES with bare-metal stents (BMS) and 2 comparing different DES, individual data on 5,381 patients with a single treated lesion and follow-up angiography at 6 to 9 months were analyzed. By 4 well-defined criteria of surrogacy, LL and %DS strongly predicted the risk of TLR, with in-segment %DS being the most highly predictive (approximately 0.95). Differences in TLR risk were fully explained statistically by their differences in LL or %DS, although LL as a surrogate was dependent on vessel size whereas %DS was not. However, because of the curvilinearity of the logistic model, trials comparing 2 effective DES can have significant differences in mean LL and %DS but small expected differences in TLR risk, especially at the lower ranges of LL and %DS. From in-stent and in-segment LL and %DS measures, logistic models can reliably estimate TLR rates for DES and BMS. These angiographic measures are thus suitable surrogate markers for clinical stent efficacy and can be used as primary end points in future DES trials to significantly reduce sample size.

Journal of the American College of Cardiology, 2006

To address the safety and efficacy of drug-eluting stents (DES) in the treatment of intermediate ... more To address the safety and efficacy of drug-eluting stents (DES) in the treatment of intermediate lesions, we performed a pooled analysis of four randomized DES versus bare-metal stent (BMS) trials and assessed outcomes among patients with intermediate lesions. BACKGROUND Before the introduction of DES, intermediate coronary lesions were commonly managed based on physiologic or anatomic assessment of lesion severity. The DES may challenge this paradigm. METHODS The study population involved 167 of 2,478 randomized patients (6.7%) with intermediate lesions (diameter stenosis Ͻ50% [mean 44%] by quantitative coronary angiography) from the Sirolimus-coated Bx Velocity Balloon Expandable Stent in the Treatment of Patients with De Novo Coronary Artery Lesions (SIRIUS), TAXUS-IV, and the First and Second First Use to Underscore Restenosis Reduction with Everolimus (FUTURE-I and -II) trials. End points examined included early (in-hospital and 30-day) and late (1-year) major adverse cardiac events (MACE), including cardiac death, myocardial infarction (MI), target vessel revascularization (TVR), stent thrombosis, and follow-up angiographic restenosis. RESULTS Patients with intermediate lesions randomized to DES versus BMS had low rates of 30-day MACE (1.1% vs. 4.0% respectively; p ϭ 0.22). At one-year follow-up, patients treated with DES versus BMS had similar rates of cardiac death (0% vs. 2.7%, respectively; p ϭ 0.11) and MI (3.4% vs. 5.4%; p ϭ 0.49) but markedly lower rates of TVR (3.4% vs. 20.3%; p ϭ 0.0004), MACE (5.6% vs. 25.4%; p ϭ 0.0003), and binary angiographic restenosis (1.8% vs. 34.0%; p Ͻ 0.0001). No patient in either group developed stent thrombosis. CONCLUSIONS Compared with BMS, treatment of intermediate lesions with DES appears safe and results in a marked reduction in clinical and angiographic restenosis. The efficacy of DES may require a reevaluation of current treatment paradigms for intermediate lesions. (J Am Coll Cardiol 2006;47:2164 -71)

European Heart Journal, 2007

Aims Major bleeding after percutaneous coronary intervention (PCI) is an independent risk factor ... more Aims Major bleeding after percutaneous coronary intervention (PCI) is an independent risk factor for early and late mortality. We developed and validated a risk score predictive of major bleeding after PCI using the femoral approach. Methods and results Baseline clinical and procedural variables from two contemporary, multicentre, randomized PCI trials were used for risk score development (the REPLACE-2 trial, n ¼ 6002) and validation (the REPLACE-1 trial, n ¼ 1056). On the basis of the odds ratio, independent risk factors were assigned a weighted integer, the sum of which comprised a total risk score. Seven variables were identified as independent correlates of major bleeding (age .55 years, female gender, estimated glomerular filtration rate ,60 mL/min/1.73 m 2 , pre-existing anaemia, administration of low-molecular-weight heparin within 48 h pre-PCI, use of glycoprotein IIb/IIIa inhibitors, and intraaortic balloon pump use). In the development set, the risk of major bleeding varied from 1.0% in patients without risk factors to 5.4% in high-risk patients. The discriminatory power of this risk model was confirmed in the validation data set (area under the receiver operating curve ¼ 0.62). Conclusion A simple risk score of baseline clinical and procedural variables is useful to predict the incidence of major peri-procedural bleeding after contemporary PCI using the femoral approach.

Clinical Journal of the American Society of Nephrology, 2008

The 1999 Canadian vascular access guidelines recommend the fistula as the access of choice. The s... more The 1999 Canadian vascular access guidelines recommend the fistula as the access of choice. The study describes the trends in hemodialysis access use, variation among provinces, and the association with mortality from 2001 to 2004. An observational study of adult patients registered in Canadian Organ Replacement Registry on hemodialysis. Access trends were examined among incident and prevalent hemodialysis patients adjusted for age, sex, body mass index, late referral, race, smoking status, province, etiology of end-stage renal disease, and comorbidities. Cox proportional hazard regression analysis was used to analyze risk for death for patients followed to December 31, 2005. From 2001 to 2004, incident catheter use increased from 76.8% to 79.1%, fistulas decreased from 21.6% to 18.6%, and grafts remained between 2.1% to 2.6%. Prevalent catheter use increased from 41.8% to 51.7%, and fistulas and grafts decreased from 46.8% to 41.6% and 11.4% to 6.7%, respectively. There was significant variation in incident and prevalent fistulae use among the provinces. Adjustment for differences in patient characteristics did not change these trends. Incident catheter use was associated with a 6 times greater risk of death compared with fistula or graft use combined. In Canada there has been a decrease in fistulae and grafts with a subsequent increase in catheters that is not explained by changes in patient characteristics. Vascular access use varied by province, suggesting differences in practice patterns. Because incident catheter use was associated with increased mortality, urgent measures are needed to develop strategies to decrease catheter use.

Clinical Journal of the American Society of Nephrology, 2012

Background and objectives In the last 15 years in Canada, there have been less stringent guidelin... more Background and objectives In the last 15 years in Canada, there have been less stringent guidelines for peritoneal dialysis (PD) adequacy, availability of novel PD solutions, and lower PD-related peritonitis rates. Effects of these changes on outcomes of incident patients treated with PD during this period are unknown.

Clinical Journal of the American Society of Nephrology, 2011

Background and objectives: An increasing number of patients are returning to dialysis after allog... more Background and objectives: An increasing number of patients are returning to dialysis after allograft loss (DAGL). These patients are at a higher mortality risk compared with incident ESRD patients. Among transplant-naïve patients, those treated with peritoneal dialysis (PD) enjoy an early survival advantage compared with those treated with hemodialysis (HD), but this advantage is not sustained over time. Whether a similar time-dependent survival advantage exists for PD-treated patients after allograft loss is unclear and may impact dialysis modality selection in these patients.

BMC Nephrology, 2010

Background: Performing clinical research among pediatric end-stage renal disease patients is chal... more Background: Performing clinical research among pediatric end-stage renal disease patients is challenging. Barriers to successful initiation and completion of clinical research projects include small sample sizes and resultant limited statistical power and lack of longitudinal follow-up for hard clinical end-points in most single center studies. Description: Existing longitudinal organ failure disease registry and administrative health datasets available within a universal access health care system can be used to study outcomes of end-stage renal disease among pediatric patients in Canada. To construct the Canadian Pediatric End-Stage Renal Disease database, registry data were linked to administrative health data through deterministic linkage techniques creating a research database which consists of socio-demographic variables, clinical variables, all-cause hospitalizations, and relevant outcomes (death and renal allograft loss) for this patient population. The research database also allows study of major cardiovascular events using previously validated administrative data definitions. Conclusion: Organ failure registry linked to health administrative data can be a powerful tool to perform longitudinal studies in pediatric end-stage renal disease patients. The rich clinical and demographic information found in this database will facilitate study of important medical and non-medical risk factors for death, graft loss and cardiovascular disease among pediatric end-stage renal disease patients.

Archives of Internal Medicine, 2012

The American Journal of Cardiology, 2007

We evaluated the utility of a routine postprocedure course of unfractionated heparin after primar... more We evaluated the utility of a routine postprocedure course of unfractionated heparin after primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) in patients not receiving glycoprotein IIb/IIIa inhibitors. In the CADILLAC study, 2,082 patients with AMI who underwent primary PCI were randomized to receive stents versus percutaneous transluminal coronary angioplasty (PTCA), each with or without abciximab. In a subset of 976 patients who did not receive abciximab, we compared outcomes of patients who received postprocedural heparin (n = 758; 78%; median duration 2 days) with those who did not. In 421 patients treated with PTCA, postprocedural heparin use was associated with lower in-hospital major adverse cardiac events (MACEs; 5.3% vs 11.4%, p = 0.069), 1-year MACEs (22% vs 31%, p = 0.08), and decreased in-hospital moderate/severe bleeding (2.3% vs 8.9%, p = 0.01). By multivariate analyses, heparin use correlated with freedom from in-hospital and 1-year MACEs in patients after PTCA. In contrast, in 555 patients who underwent stenting, postprocedural heparin use was associated with increased bleeding and hospitalization costs without a decrease in early or late MACEs. In conclusion, in patients with AMI treated with coronary stenting without glycoprotein IIb/IIIa inhibitors, routine postprocedural heparin was not associated with any significant benefits and may be safely omitted. However, in a subset of patients treated with PTCA, postprocedural heparin use was independently associated with fewer in-hospital and 1-year MACEs.

The American Journal of Cardiology, 2007

Despite the well-recognized role of platelets in the pathogenesis of acute myocardial infarction ... more Despite the well-recognized role of platelets in the pathogenesis of acute myocardial infarction (AMI) and in the vascular responses to angioplasty, the relation between platelet count and outcomes after primary percutaneous coronary intervention (PCI) in AMI is unknown. We therefore determined the effect of baseline platelet count on clinical and angiographic outcomes of patients with AMI undergoing primary PCI. In the prospective, randomized CADILLAC trial, platelet count on admission was available in 2,021 of 2,082 patients (97.0%). Angiographic results and outcomes at 30 days and 1 year were stratified by quartiles of platelet count. Median platelet count was 231 ؋ 10 9 /L (range 38 to 709). Primary PCI angiographic success rates were independent of platelet count. The 30-day incidence of target vessel thrombosis or reocclusion increased steadily across the higher quartiles of baseline platelet count (0.2%, 0.6%, 1.0%, and 2.0%, p ‫؍‬ 0.027). At 1 year, patients with a baseline platelet count >234 versus <234 ؋ 10 9 /L had higher rates of death or reinfarction (8.9% vs 4.5%, p <0.0001), death (5.8% vs 3.1%, p ‫؍‬ 0.002), and reinfarction (3.4% vs 1.6%, p ‫؍‬ 0.008). By multivariable analysis, a higher baseline platelet count was the strongest predictor of 1-year death or reinfarction (hazard ratio [HR] per 10,000 increase in platelet count 1.02, 95% confidence interval [CI] 1.02 to 1.07, p <0.0001) and independently predicted reinfarction (HR 1.06, 95% CI 1.02 to 1.09, p ‫؍‬ 0.002) and cardiac mortality (HR 1.03, 95% CI 1.00 to 1.06, p ‫؍‬ 0.055) at 1 year. In conclusion, a higher baseline platelet count in patients with AMI is a powerful independent predictor of death and reinfarction within the first year after primary PCI.

The American Journal of Cardiology, 2007

The impact of time to treatment on outcomes after primary percutaneous coronary intervention (PCI... more The impact of time to treatment on outcomes after primary percutaneous coronary intervention (PCI) is controversial, and there are few data about time to treatment and infarct size. The EMERALD trial randomly assigned 501 high-risk patients with ST-elevation myocardial infarction undergoing primary PCI to stenting with or without GuardWire (Medtronic, Santa Rosa, California) distal protection. Infarct size using sestamibi imaging at 5 to 14 days and clinical outcomes were examined by time to treatment. There were no differences in outcomes between distal protection and control patients. Shorter time to reperfusion (<2 vs 2 to 3 vs >3 to 4 vs >4 hours) was associated with smaller infarct size (2% vs 9% vs 12% vs 11%, p ‫؍‬ 0.026), trends for better myocardial blush (p ‫؍‬ 0.08), and lower 6-month mortality rates (0% vs 0% vs 2.4% vs 5.3%, p ‫؍‬ 0.06). Incremental delays in reperfusion after 2 hours had little impact on infarct size. Shorter time to reperfusion impacted on infarct size in patients with anterior infarction (0% vs 17% vs 20.5% vs 30.5%, p ‫؍‬ 0.026), but not nonanterior infarction (3% vs 7% vs 7.5% vs 10%, p ‫؍‬ 0.23, p ‫؍‬ 0.022 for interaction). In conclusion, very early reperfusion with primary PCI is associated with smaller infarct size and has a much greater impact in anterior versus nonanterior infarction. Incremental delays in reperfusion after 2 hours have less effect on infarct size. These data have implications regarding the triage of patients for primary PCI. © 2007 Elsevier Inc. All rights reserved. (Am J Cardiol 2007;99:1680 -1686)

The American Journal of Cardiology, 2007

This study was conducted to determine the influence of lesion preparation using the AngioSculpt b... more This study was conducted to determine the influence of lesion preparation using the AngioSculpt balloon on final stent expansion. Stent expansion remains an important predictor of restenosis and subacute thrombosis, even in the drug-eluting stent (DES) era. In these patients, the role of different predilation strategies has yet to be established. Two hundred ninety-nine consecutive de novo lesions treated with 1 >2.5-mm DES (Cypher or Taxus) under intravascular ultrasound guidance without postdilation, using 3 implantation strategies, were studied: (1) direct stenting without predilation (n ‫؍‬ 145), (2) predilation with a conventional semi-compliant balloon (n ‫؍‬ 117), and (3) predilation with the AngioSculpt balloon (n ‫؍‬ 37). Stent expansion was defined as the ratio of intravascular ultrasound-measured minimum stent diameter and minimum stent area to the manufacturer's predicted stent diameter and area. These ratios were larger after AngioSculpt predilation, and a greater percentage of stents had final minimum stent areas >5.0 mm 2 (another commonly accepted criterion of adequate DES expansion). Lesion morphology, stent and lesion length, and reference vessel size did not affect DES expansion. In conclusion, in this observational, nonrandomized study, pretreatment with the AngioSculpt balloon enhanced stent expansion and minimized the difference between predicted and achieved stent dimensions.

Canadian Medical Association Journal, Apr 11, 2021

eratinocyte carcinoma (also called nonmelanoma skin cancer) includes basal and squamous cell carc... more eratinocyte carcinoma (also called nonmelanoma skin cancer) includes basal and squamous cell carcinoma, the 2 most common malignancies in North America. 1,2 More than 76 000 and 5.4 million cases are diagnosed annually in Canada and the United States, respectively. 1,2 Melanoma is the fifth most common malignancy in the US, with 83 362 annual cases, 10 000 deaths and incidence rates rising by 10% between 2005 and 2015. 3-5 It is estimated that there were 8000 new melanoma cases and 1300 related deaths in Canada in 2020. 6 Given the high and increasing population burden of these skin cancers, identifying modifiable risk factors is important. 7,8 Ultraviolet (UV) radiation exposure is the most important environmental risk factor for skin cancer. 9,10 Medication-induced phototoxicity, in which medications interact with UV radiation to cause cellular damage in the skin, may increase the carcinogenic potential of sun exposure. 11 Antihypertensive medications are used by about 1 in 5 adults, 12 and thiazide diuretics, calcium channel blockers, β-blockers, angiotensin II receptor blockers (ARBs) and angiotensin-converting enzyme (ACE) inhibitors have all been reported to be phototoxic. 11,13 Hydrochlorothiazide is first-line pharmacotherapy for hypertension 14 and is considered the most phototoxic anti hypertensive medication. 11,13 It has been implicated in increasing the risk of keratinocyte carcinoma, with 2 recent case-control studies 15,16 prompting Health Canada, the European Medicines Agency and the US Food and Drug Administration to issue warnings regarding prolonged use. 17-19 Weaker associations have been reported between thiazides and melanoma, 20 and there is conflicting evidence on the association between other antihypertensive classes and skin cancer. 21 To determine whether exposure to thiazides or other antihypertensive medications is associated with skin cancer, we conducted a population-based inception cohort study.

Peritoneal Dialysis International, May 1, 2015

A significant proportion of peritoneal dialysis (PD) patients receive an initial period of hemodi... more A significant proportion of peritoneal dialysis (PD) patients receive an initial period of hemodialysis (HD) before transitioning to PD (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;PD-switch&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;). We sought to better understand the risks of PD technique failure (TF) and mortality for those patients compared with patients starting with PD as their first dialysis modality (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;PD-first&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;). Using Canadian Organ Replacement Register data, we compared the risk of PD TF between PD-first and PD-switch patients within the first year after HD initiation. In a secondary analysis, the PD-switch patients were stratified into three groups based on timing of the switch from initial HD to PD as follows: 0 - 90 days, 91 - 180 days, and 181 - 365 days. Each group was compared with PD-first patients for risk of PD TF and death. Between 2001 and 2010, 9404 patients initiated PD as their first renal replacement therapy, and 3757 switched from HD to PD. After multivariable adjustment, the risk of PD TF was higher among PD-switch patients than among PD-first patients [adjusted hazard ratio (AHR): 1.37; 95% confidence interval (CI): 1.26 to 1.49], particularly within the first year after the switch from HD to PD (AHR: 1.51; 95% CI: 1.36 to 1.68). There was no association between time on HD within the first year and subsequent risk of PD TF. For all the stratified PD-switch groups, death rates were higher than those for PD-first patients. Compared with patients who start renal replacement therapy with PD, those who transfer from HD to PD within the first year on dialysis experience higher rates of PD TF and death, with the highest risk being observed in the initial year after the switch to PD.

American journal of kidney diseases : the official journal of the National Kidney Foundation, Jan 16, 2015

While central venous catheter (CVC) use has expanded home hemodialysis (HHD) eligibility to many ... more While central venous catheter (CVC) use has expanded home hemodialysis (HHD) eligibility to many patients who may be unable to self-cannulate an arteriovenous (AV) access, the association between CVC use and mortality has not been directly examined among HHD patients. Registry-based retrospective observational cohort study. Incident HHD patients in The Canadian Organ Replacement Register who had information for vascular access type (CVC vs AV access) within the first year of HHD therapy initiation. Use of a CVC versus an AV access (AV fistula or graft) within the first year of HHD therapy initiation. The composite of all-cause mortality and technique failure (long-term transfer to an alternate dialysis modality). A Cox proportional hazards model was used to evaluate the adjusted composite outcome and each outcome separately. 1,869 patients initiated HHD therapy in Canada in 1996 to 2012, of whom 1,217 had an access type recorded within the first year of HHD therapy initiation. Compa...

Peritoneal Dialysis International, 2013

A significant proportion of peritoneal dialysis (PD) patients receive an initial period of hemodi... more A significant proportion of peritoneal dialysis (PD) patients receive an initial period of hemodialysis (HD) before transitioning to PD (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;PD-switch&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;). We sought to better understand the risks of PD technique failure (TF) and mortality for those patients compared with patients starting with PD as their first dialysis modality (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;PD-first&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;). Using Canadian Organ Replacement Register data, we compared the risk of PD TF between PD-first and PD-switch patients within the first year after HD initiation. In a secondary analysis, the PD-switch patients were stratified into three groups based on timing of the switch from initial HD to PD as follows: 0 - 90 days, 91 - 180 days, and 181 - 365 days. Each group was compared with PD-first patients for risk of PD TF and death. Between 2001 and 2010, 9404 patients initiated PD as their first renal replacement therapy, and 3757 switched from HD to PD. After multivariable adjustment, the risk of PD TF was higher among PD-switch patients than among PD-first patients [adjusted hazard ratio (AHR): 1.37; 95% confidence interval (CI): 1.26 to 1.49], particularly within the first year after the switch from HD to PD (AHR: 1.51; 95% CI: 1.36 to 1.68). There was no association between time on HD within the first year and subsequent risk of PD TF. For all the stratified PD-switch groups, death rates were higher than those for PD-first patients. Compared with patients who start renal replacement therapy with PD, those who transfer from HD to PD within the first year on dialysis experience higher rates of PD TF and death, with the highest risk being observed in the initial year after the switch to PD.

Kidney International, 2005

The relationship between low hematocrit and contrast-induced nephropathy has not been investigate... more The relationship between low hematocrit and contrast-induced nephropathy has not been investigated. Of 6,773 consecutive patients treated with percutaneous coronary intervention, contrast-induced nephropathy (an increase of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;/=25% or &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;/=0.5 mg/dL in preprocedure serum creatinine, at 48 hours postprocedure) occurred in 942 (13.9%) patients. Rates of contrast-induced nephropathy steadily increased as baseline hematocrit quintile decreased (from 10.3% in the highest quintile to 23.3% in the lowest quintile) (chi(2) for trend, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001). Stratification by baseline estimated glomerular filtration rate (eGFR) and baseline hematocrit showed that the rates of contrast-induced nephropathy were the highest (28.8%) in patients who had the lowest level for both baseline eGFR and hematocrit. Patients with the lowest eGFR but relatively high baseline hematocrit values had remarkably lower rates of contrast-induced nephropathy (15.8%, 12.3%, 17.1%, and 15.4% in 2nd, 3rd, 4th, and 5th quintiles of baseline hematocrit, respectively) (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001). The rates of contrast-induced nephropathy increased with increment in change in hematocrit. Patients in the lowest quintile of baseline hematocrit with absolute hematocrit drop &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;5.9% had almost doubled rates of contrast-induced nephropathy compared with patients with hematocrit change &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;3.4% (38.1% vs. 18.8%, respectively) (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001). By multivariate analysis, lower baseline hematocrit was an…

Journal of the American Society of Nephrology, 2011

Several comparisons of peritoneal dialysis (PD) and hemodialysis (HD) in incident patients with E... more Several comparisons of peritoneal dialysis (PD) and hemodialysis (HD) in incident patients with ESRD demonstrate superior survival in PD-treated patients within the first 1 to 2 years. These survival differences may be due to higher HD-related mortality as a result of high rates of incident central venous catheter (CVC) use or due to an initial survival advantage conferred by PD. We compared the survival of incident PD patients with those who initiated HD with a CVC (HD-CVC) or with a functional arteriovenous fistula or arteriovenous graft (HD-AVF/AVG). We used multivariable piece-wise exponential nonproportional and proportional hazards models to evaluate early (1 year) mortality as well as overall mortality during the period of observation using an intention-to-treat approach. We identified 40,526 incident adult dialysis patients from the Canadian Organ Replacement Register (2001Register ( to 2008. Compared with the 7412 PD patients, 1-year mortality was similar for the 6663 HD-AVF/AVG patients but was 80% higher for the 24,437 HD-CVC patients (adjusted HR, 1.8; 95% confidence intervals [CI], 1.6 to 1.9). During the entire period of follow-up, HD-AVF/AVG patients had a lower risk for death, and HD-CVC patients had a higher risk for death compared with patients on PD. In conclusion, the use of CVCs in incident HD patients largely accounts for the early survival benefit seen with PD.

Journal of the American College of Cardiology, 2006

The objectives of the study were to evaluate the effect of angiographic follow-up on revasculariz... more The objectives of the study were to evaluate the effect of angiographic follow-up on revascularization rates in the TAXUS-IV trial and to determine whether the relative benefit of paclitaxel-eluting stent implantation compared with bare metal stent implantation was modified by angiographic follow-up. BACKGROUND Although several clinical trials have demonstrated that drug-eluting stents (DES) reduce restenosis compared with bare-metal stents (BMS), virtually all of these studies have incorporated angiographic follow-up.

Journal of the American College of Cardiology, 2008

We sought to validate 4 angiographic measures as potential surrogates for clinical restenosis (ta... more We sought to validate 4 angiographic measures as potential surrogates for clinical restenosis (target lesion revascularization [TLR]) after stent implantation. Given the low revascularization rates with drug-eluting stents (DES), an angiographic surrogate of TLR is desirable to reduce the sample size required to demonstrate efficacy in future trials of antirestenosis devices. We evaluated 4 potential angiographic measures (late loss [LL] and percent diameter stenosis [%DS], both in-stent and in-segment) as a surrogate for TLR at 1 year. From 11 multicenter, prospective randomized stent trials, 9 comparing DES with bare-metal stents (BMS) and 2 comparing different DES, individual data on 5,381 patients with a single treated lesion and follow-up angiography at 6 to 9 months were analyzed. By 4 well-defined criteria of surrogacy, LL and %DS strongly predicted the risk of TLR, with in-segment %DS being the most highly predictive (approximately 0.95). Differences in TLR risk were fully explained statistically by their differences in LL or %DS, although LL as a surrogate was dependent on vessel size whereas %DS was not. However, because of the curvilinearity of the logistic model, trials comparing 2 effective DES can have significant differences in mean LL and %DS but small expected differences in TLR risk, especially at the lower ranges of LL and %DS. From in-stent and in-segment LL and %DS measures, logistic models can reliably estimate TLR rates for DES and BMS. These angiographic measures are thus suitable surrogate markers for clinical stent efficacy and can be used as primary end points in future DES trials to significantly reduce sample size.

Journal of the American College of Cardiology, 2006

To address the safety and efficacy of drug-eluting stents (DES) in the treatment of intermediate ... more To address the safety and efficacy of drug-eluting stents (DES) in the treatment of intermediate lesions, we performed a pooled analysis of four randomized DES versus bare-metal stent (BMS) trials and assessed outcomes among patients with intermediate lesions. BACKGROUND Before the introduction of DES, intermediate coronary lesions were commonly managed based on physiologic or anatomic assessment of lesion severity. The DES may challenge this paradigm. METHODS The study population involved 167 of 2,478 randomized patients (6.7%) with intermediate lesions (diameter stenosis Ͻ50% [mean 44%] by quantitative coronary angiography) from the Sirolimus-coated Bx Velocity Balloon Expandable Stent in the Treatment of Patients with De Novo Coronary Artery Lesions (SIRIUS), TAXUS-IV, and the First and Second First Use to Underscore Restenosis Reduction with Everolimus (FUTURE-I and -II) trials. End points examined included early (in-hospital and 30-day) and late (1-year) major adverse cardiac events (MACE), including cardiac death, myocardial infarction (MI), target vessel revascularization (TVR), stent thrombosis, and follow-up angiographic restenosis. RESULTS Patients with intermediate lesions randomized to DES versus BMS had low rates of 30-day MACE (1.1% vs. 4.0% respectively; p ϭ 0.22). At one-year follow-up, patients treated with DES versus BMS had similar rates of cardiac death (0% vs. 2.7%, respectively; p ϭ 0.11) and MI (3.4% vs. 5.4%; p ϭ 0.49) but markedly lower rates of TVR (3.4% vs. 20.3%; p ϭ 0.0004), MACE (5.6% vs. 25.4%; p ϭ 0.0003), and binary angiographic restenosis (1.8% vs. 34.0%; p Ͻ 0.0001). No patient in either group developed stent thrombosis. CONCLUSIONS Compared with BMS, treatment of intermediate lesions with DES appears safe and results in a marked reduction in clinical and angiographic restenosis. The efficacy of DES may require a reevaluation of current treatment paradigms for intermediate lesions. (J Am Coll Cardiol 2006;47:2164 -71)

European Heart Journal, 2007

Aims Major bleeding after percutaneous coronary intervention (PCI) is an independent risk factor ... more Aims Major bleeding after percutaneous coronary intervention (PCI) is an independent risk factor for early and late mortality. We developed and validated a risk score predictive of major bleeding after PCI using the femoral approach. Methods and results Baseline clinical and procedural variables from two contemporary, multicentre, randomized PCI trials were used for risk score development (the REPLACE-2 trial, n ¼ 6002) and validation (the REPLACE-1 trial, n ¼ 1056). On the basis of the odds ratio, independent risk factors were assigned a weighted integer, the sum of which comprised a total risk score. Seven variables were identified as independent correlates of major bleeding (age .55 years, female gender, estimated glomerular filtration rate ,60 mL/min/1.73 m 2 , pre-existing anaemia, administration of low-molecular-weight heparin within 48 h pre-PCI, use of glycoprotein IIb/IIIa inhibitors, and intraaortic balloon pump use). In the development set, the risk of major bleeding varied from 1.0% in patients without risk factors to 5.4% in high-risk patients. The discriminatory power of this risk model was confirmed in the validation data set (area under the receiver operating curve ¼ 0.62). Conclusion A simple risk score of baseline clinical and procedural variables is useful to predict the incidence of major peri-procedural bleeding after contemporary PCI using the femoral approach.

Clinical Journal of the American Society of Nephrology, 2008

The 1999 Canadian vascular access guidelines recommend the fistula as the access of choice. The s... more The 1999 Canadian vascular access guidelines recommend the fistula as the access of choice. The study describes the trends in hemodialysis access use, variation among provinces, and the association with mortality from 2001 to 2004. An observational study of adult patients registered in Canadian Organ Replacement Registry on hemodialysis. Access trends were examined among incident and prevalent hemodialysis patients adjusted for age, sex, body mass index, late referral, race, smoking status, province, etiology of end-stage renal disease, and comorbidities. Cox proportional hazard regression analysis was used to analyze risk for death for patients followed to December 31, 2005. From 2001 to 2004, incident catheter use increased from 76.8% to 79.1%, fistulas decreased from 21.6% to 18.6%, and grafts remained between 2.1% to 2.6%. Prevalent catheter use increased from 41.8% to 51.7%, and fistulas and grafts decreased from 46.8% to 41.6% and 11.4% to 6.7%, respectively. There was significant variation in incident and prevalent fistulae use among the provinces. Adjustment for differences in patient characteristics did not change these trends. Incident catheter use was associated with a 6 times greater risk of death compared with fistula or graft use combined. In Canada there has been a decrease in fistulae and grafts with a subsequent increase in catheters that is not explained by changes in patient characteristics. Vascular access use varied by province, suggesting differences in practice patterns. Because incident catheter use was associated with increased mortality, urgent measures are needed to develop strategies to decrease catheter use.

Clinical Journal of the American Society of Nephrology, 2012

Background and objectives In the last 15 years in Canada, there have been less stringent guidelin... more Background and objectives In the last 15 years in Canada, there have been less stringent guidelines for peritoneal dialysis (PD) adequacy, availability of novel PD solutions, and lower PD-related peritonitis rates. Effects of these changes on outcomes of incident patients treated with PD during this period are unknown.

Clinical Journal of the American Society of Nephrology, 2011

Background and objectives: An increasing number of patients are returning to dialysis after allog... more Background and objectives: An increasing number of patients are returning to dialysis after allograft loss (DAGL). These patients are at a higher mortality risk compared with incident ESRD patients. Among transplant-naïve patients, those treated with peritoneal dialysis (PD) enjoy an early survival advantage compared with those treated with hemodialysis (HD), but this advantage is not sustained over time. Whether a similar time-dependent survival advantage exists for PD-treated patients after allograft loss is unclear and may impact dialysis modality selection in these patients.

BMC Nephrology, 2010

Background: Performing clinical research among pediatric end-stage renal disease patients is chal... more Background: Performing clinical research among pediatric end-stage renal disease patients is challenging. Barriers to successful initiation and completion of clinical research projects include small sample sizes and resultant limited statistical power and lack of longitudinal follow-up for hard clinical end-points in most single center studies. Description: Existing longitudinal organ failure disease registry and administrative health datasets available within a universal access health care system can be used to study outcomes of end-stage renal disease among pediatric patients in Canada. To construct the Canadian Pediatric End-Stage Renal Disease database, registry data were linked to administrative health data through deterministic linkage techniques creating a research database which consists of socio-demographic variables, clinical variables, all-cause hospitalizations, and relevant outcomes (death and renal allograft loss) for this patient population. The research database also allows study of major cardiovascular events using previously validated administrative data definitions. Conclusion: Organ failure registry linked to health administrative data can be a powerful tool to perform longitudinal studies in pediatric end-stage renal disease patients. The rich clinical and demographic information found in this database will facilitate study of important medical and non-medical risk factors for death, graft loss and cardiovascular disease among pediatric end-stage renal disease patients.

Archives of Internal Medicine, 2012

The American Journal of Cardiology, 2007

We evaluated the utility of a routine postprocedure course of unfractionated heparin after primar... more We evaluated the utility of a routine postprocedure course of unfractionated heparin after primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) in patients not receiving glycoprotein IIb/IIIa inhibitors. In the CADILLAC study, 2,082 patients with AMI who underwent primary PCI were randomized to receive stents versus percutaneous transluminal coronary angioplasty (PTCA), each with or without abciximab. In a subset of 976 patients who did not receive abciximab, we compared outcomes of patients who received postprocedural heparin (n = 758; 78%; median duration 2 days) with those who did not. In 421 patients treated with PTCA, postprocedural heparin use was associated with lower in-hospital major adverse cardiac events (MACEs; 5.3% vs 11.4%, p = 0.069), 1-year MACEs (22% vs 31%, p = 0.08), and decreased in-hospital moderate/severe bleeding (2.3% vs 8.9%, p = 0.01). By multivariate analyses, heparin use correlated with freedom from in-hospital and 1-year MACEs in patients after PTCA. In contrast, in 555 patients who underwent stenting, postprocedural heparin use was associated with increased bleeding and hospitalization costs without a decrease in early or late MACEs. In conclusion, in patients with AMI treated with coronary stenting without glycoprotein IIb/IIIa inhibitors, routine postprocedural heparin was not associated with any significant benefits and may be safely omitted. However, in a subset of patients treated with PTCA, postprocedural heparin use was independently associated with fewer in-hospital and 1-year MACEs.

The American Journal of Cardiology, 2007

Despite the well-recognized role of platelets in the pathogenesis of acute myocardial infarction ... more Despite the well-recognized role of platelets in the pathogenesis of acute myocardial infarction (AMI) and in the vascular responses to angioplasty, the relation between platelet count and outcomes after primary percutaneous coronary intervention (PCI) in AMI is unknown. We therefore determined the effect of baseline platelet count on clinical and angiographic outcomes of patients with AMI undergoing primary PCI. In the prospective, randomized CADILLAC trial, platelet count on admission was available in 2,021 of 2,082 patients (97.0%). Angiographic results and outcomes at 30 days and 1 year were stratified by quartiles of platelet count. Median platelet count was 231 ؋ 10 9 /L (range 38 to 709). Primary PCI angiographic success rates were independent of platelet count. The 30-day incidence of target vessel thrombosis or reocclusion increased steadily across the higher quartiles of baseline platelet count (0.2%, 0.6%, 1.0%, and 2.0%, p ‫؍‬ 0.027). At 1 year, patients with a baseline platelet count >234 versus <234 ؋ 10 9 /L had higher rates of death or reinfarction (8.9% vs 4.5%, p <0.0001), death (5.8% vs 3.1%, p ‫؍‬ 0.002), and reinfarction (3.4% vs 1.6%, p ‫؍‬ 0.008). By multivariable analysis, a higher baseline platelet count was the strongest predictor of 1-year death or reinfarction (hazard ratio [HR] per 10,000 increase in platelet count 1.02, 95% confidence interval [CI] 1.02 to 1.07, p <0.0001) and independently predicted reinfarction (HR 1.06, 95% CI 1.02 to 1.09, p ‫؍‬ 0.002) and cardiac mortality (HR 1.03, 95% CI 1.00 to 1.06, p ‫؍‬ 0.055) at 1 year. In conclusion, a higher baseline platelet count in patients with AMI is a powerful independent predictor of death and reinfarction within the first year after primary PCI.

The American Journal of Cardiology, 2007

The impact of time to treatment on outcomes after primary percutaneous coronary intervention (PCI... more The impact of time to treatment on outcomes after primary percutaneous coronary intervention (PCI) is controversial, and there are few data about time to treatment and infarct size. The EMERALD trial randomly assigned 501 high-risk patients with ST-elevation myocardial infarction undergoing primary PCI to stenting with or without GuardWire (Medtronic, Santa Rosa, California) distal protection. Infarct size using sestamibi imaging at 5 to 14 days and clinical outcomes were examined by time to treatment. There were no differences in outcomes between distal protection and control patients. Shorter time to reperfusion (<2 vs 2 to 3 vs >3 to 4 vs >4 hours) was associated with smaller infarct size (2% vs 9% vs 12% vs 11%, p ‫؍‬ 0.026), trends for better myocardial blush (p ‫؍‬ 0.08), and lower 6-month mortality rates (0% vs 0% vs 2.4% vs 5.3%, p ‫؍‬ 0.06). Incremental delays in reperfusion after 2 hours had little impact on infarct size. Shorter time to reperfusion impacted on infarct size in patients with anterior infarction (0% vs 17% vs 20.5% vs 30.5%, p ‫؍‬ 0.026), but not nonanterior infarction (3% vs 7% vs 7.5% vs 10%, p ‫؍‬ 0.23, p ‫؍‬ 0.022 for interaction). In conclusion, very early reperfusion with primary PCI is associated with smaller infarct size and has a much greater impact in anterior versus nonanterior infarction. Incremental delays in reperfusion after 2 hours have less effect on infarct size. These data have implications regarding the triage of patients for primary PCI. © 2007 Elsevier Inc. All rights reserved. (Am J Cardiol 2007;99:1680 -1686)

The American Journal of Cardiology, 2007

This study was conducted to determine the influence of lesion preparation using the AngioSculpt b... more This study was conducted to determine the influence of lesion preparation using the AngioSculpt balloon on final stent expansion. Stent expansion remains an important predictor of restenosis and subacute thrombosis, even in the drug-eluting stent (DES) era. In these patients, the role of different predilation strategies has yet to be established. Two hundred ninety-nine consecutive de novo lesions treated with 1 >2.5-mm DES (Cypher or Taxus) under intravascular ultrasound guidance without postdilation, using 3 implantation strategies, were studied: (1) direct stenting without predilation (n ‫؍‬ 145), (2) predilation with a conventional semi-compliant balloon (n ‫؍‬ 117), and (3) predilation with the AngioSculpt balloon (n ‫؍‬ 37). Stent expansion was defined as the ratio of intravascular ultrasound-measured minimum stent diameter and minimum stent area to the manufacturer's predicted stent diameter and area. These ratios were larger after AngioSculpt predilation, and a greater percentage of stents had final minimum stent areas >5.0 mm 2 (another commonly accepted criterion of adequate DES expansion). Lesion morphology, stent and lesion length, and reference vessel size did not affect DES expansion. In conclusion, in this observational, nonrandomized study, pretreatment with the AngioSculpt balloon enhanced stent expansion and minimized the difference between predicted and achieved stent dimensions.