Christopher Kwolek - Academia.edu (original) (raw)

Papers by Christopher Kwolek

Journal of Surgical Research, 1998

In conjunction with the VA reorganization to promote greater efficiency of health care provision,... more In conjunction with the VA reorganization to promote greater efficiency of health care provision, ambulatory surgery (AS) programs have been created. These programs institute outpatient preoperative assessment and operative management. This study examines the impact of these process changes on resources utilized by patients requiring repair of abdominal aortic aneurysms (AAAs). The medical records of 15 consecutively treated patients undergoing elective, infrarenal AAA repair before (1992-1993) and after (1995-1996) AS implementation were reviewed. Resource utilization was assessed by evaluating preoperative tests performed (inpatient or outpatient), ICU days, and inpatient length of stay (LOS). Postoperative morbidity and mortality were noted. Patient age, AAA size, and prevalence of diabetes mellitus, hypertension, cardiac disease, COPD, and tobacco use were similar between the two groups. Abdominal ultrasound, CT scanning, and angiography were significantly more frequently performed on an outpatient basis after implementation of the AS program. The median preoperative LOS was reduced in the AS group (1 vs 6 days, P = 0.001, Student t test), resulting in a lower inpatient LOS (11 vs 16, P < 0.01, Student t test). All patients survived and the incidence of complications was similar between the groups. Hospital resource utilization was significantly decreased, largely by shifting preoperative assessment to the outpatient setting. This study illustrates that benefits of an ambulatory surgery program can be extended beyond facilitating outpatient operations and should result in decreased length of hospitalization for other major surgical procedures, such as abdominal aortic aneurysm repair.

American Surgeon, Apr 1, 2001

Telemedicine (TM) using closed-circuit television systems allows specialists to evaluate patients... more Telemedicine (TM) using closed-circuit television systems allows specialists to evaluate patients at remote sites. Because an integral part of the vascular examination involves palpation of peripheral pulses the applicability of TM for the evaluation of vascular surgery patients is open to question. This study was carried out to test the hypothesis that TM is as effective as direct patient examination for the development of a care plan in vascular patients. Sixty-four vascular evaluations were done in 32 patients. The patients presented with a variety of vascular problems and were seen in regularly scheduled rural outreach vascular clinics. Two faculty vascular surgeons evaluated each patient; one was on site and the second, using TM, remained at the medical center. Each surgeon was blinded to the other's findings. The TM physician was aided by a nonphysician assistant, who obtained blood pressures, utilized a continuous-wave Doppler probe, positioned the patient, and operated the TM equipment. The results of each surgeon's evaluations were compared. Patient and physician satisfaction with the TM evaluation was appraised by questionnaires. Eight patients were seen for initial evaluations; 24 patients were seen for follow-up visits. Patients were seen with a variety of diagnoses, including aneurysm (seven), cerebrovascular disease (five), lower extremity occlusive disease (13), multiple vascular problems (three), and other disease (four). The average duration for the TM and on-site evaluations were 20.6+/-1.4 and 19.0+/-1.3 minutes, respectively (P = not significant). Physician concordance, as determined by treatment recommendations, was the same in 29 (91%) patients. Physician confidence in the ability to obtain an accurate history via TM was rated as excellent in 97 per cent; confidence in the TM physical examination was rated as excellent in 70 per cent. All patients rated the TM evaluation as the "same as" or "better than" the on-site examination, and all indicated a preference for being seen locally using TM as opposed to traveling to a regional medical center. We conclude that the TM evaluation of vascular patients is accurate and is as effective as on-site evaluations for a variety of vascular problems. Important adjuncts to enhance the success of a TM evaluation are physician experience with the technology and the presence of a knowledgeable on-site assistant. This technology can be easily adapted to other clinical situations.

Vascular Surgery, Jul 1, 2000

Recent reports have documented the use of covered stents for the treatment of traumatic injuries ... more Recent reports have documented the use of covered stents for the treatment of traumatic injuries to the vascular system. We report the first use of an autologous vein-covered Palmaz stent for the treatment of a popliteal artery pseudoaneurysm. A 5-foot-2-inch, 320-pound woman was referred to the authors' institution with new onset of pain and ecchymosis in the popliteal fossa while on Coumadin therapy for treatment of a deep venous thrombosis. She had undergone left total knee replacement 13 months previously. A contrast computed tomography (CT) scan confirmed an 8-cm aneurysm behind the knee. The patient was offered endovascular treatment of this aneurysm as an alternative to bypass surgery. Intraoperative arteriography was performed through a superficial femoral artery cutdown and demonstrated a large popliteal pseudoaneurysm. A 2-cm Palmaz stent was attached to a 6-mm-wide-by-2-cm-long side branch of greater saphenous vein and was used to occlude the neck of the pseudoaneurysm. Completion arteriogram confirmed exclusion of the pseudoaneurysm, and the patient regained a dorsalis pedis pulse after the procedure. Patency at 12 months was confirmed by duplex examination, with the presence of a normal ankle-brachial index (ABI) and normal velocities. The use of endovascular stent grafts made with autogenous tissue offers an attractive alternative to open surgical procedures in technically complex cases. This case demonstrates that a combined open surgical and endovascular approach can be successfully used for the management of traumatic injuries to the popliteal artery. Further investigation will be necessary to evaluate the long-term efficacy of this approach in managing popliteal artery injuries.

Annals of Vascular Surgery, May 1, 2000

Adult human saphenous vein endothelial cells (HVEC) were cultured in a compliant tubular device a... more Adult human saphenous vein endothelial cells (HVEC) were cultured in a compliant tubular device and evaluated by Northern hybridization for the effects of combined pressurized pulsatile flow and cyclic strain on the expression of mRNAs for endothelin-1 (ET-1), endothelial cell nitric oxide synthase (ecNOS), tissue plasminogen activator (tPA), and plasminogen activator inhibitor type 1 (PAI-1). The hemodynamic environment was designed to mimic shear stress conditions at the distal anastomosis of a saphenous vein graft, a common site of intimal proliferation. Steady-state mRNA levels in experimental tubes were expressed relative to that in controls. No changes were observed in ET-1 mRNA after 1 and 24 hr, but a 50% decrease in experimental cultures was observed after 48 hr in the vascular simulating device. Similar results were obtained for ecNOS mRNA, although a subgroup (4 of 11) showed a significant decrease (>50%) by 24 hr. For tPA mRNA, no change was observed after 1 hr, but a significant decrease (>60%) was measured after 24 hr and no message was detectable after 48 hr. Steady-state levels for PAI-1 mRNA remained unchanged through 48 hr of treatment. These results show that pressure, pulsatile flow, and cyclic strain, when applied in concert, differentially alter vasoactive and fibrinolytic functions in HVEC. Moreover, the dramatic decrease in steady-state levels of tPA mRNA is consistent with a shift toward an increased thrombotic state.

Journal of Vascular Surgery, Feb 1, 2004

Objective: Clinical and anatomic factors predictive of a favorable response to renal revasculariz... more Objective: Clinical and anatomic factors predictive of a favorable response to renal revascularization performed for renal function salvage remain poorly defined. To clarify decision making in such patients we reviewed a contemporary experience of surgical renal artery revascularization (RAR) performed primarily for preservation of renal function. Methods: Between June 1990 and March 2001 (ensuring 1 year minimum follow-up), 96 patients with renal insufficiency (serum creatinine [Cr] concentration >1.5 mg/dL) and hypertension underwent RAR for preservation of renal function. Study end points included early and late renal function response, progression to dialysis dependence, and long-term survival. Variables potentially associated with these end points were assessed with univariate analysis, Cox regression analysis, and logistic regression analysis, and survival was assessed with the Kaplan-Meier method. Results: Perioperative failure of RAR occurred in 3 patients (3%), with perioperative mortality in 4 patients (4.1%); thus 92 patients were available for long-term follow-up (mean, 39 months). Mean patient age was 70 ؎ 9 years with a mean baseline Cr of 2.6 mg/dL (range, 1.5-7.8 mg/dL). Operative management consisted of aortorenal bypass in 38% of patients, extraanatomic bypass in 38% of patients, and endarterectomy in 24% of patients; 32% of patients required combined aortic revascularization and RAR, and 27% underwent bilateral RAR. At hospital discharge renal function had improved (20% decrement in Cr) in 41 (43%) patients, including 7 patients who were removed from dialysis; remained unchanged in 40 (41%) patients; and declined (20% increase in Cr) in 15 (16%) patients. At last follow-up renal function was either improved or unchanged in 72% of patients. Predictors of a favorable response to RAR at last follow-up included stable Cr at hospital discharge (odds ratio [OR], 7.1; 95% confidence interval [CI], 2.5-21.8; P ‫؍‬ .0004) and decreased Cr at hospital discharge (OR, 16; 95% CI, 1.6-307.8; P < .0001); bilateral renal artery repair (OR, 3.1; 95% CI, 0.9-10.6; P ‫؍‬ .07) approached clinical significance. Predictors of worsened excretory function at last follow-up included decline of renal function at hospital discharge (OR, 28.9; 95% CI, 5.0-165.4; P ‫؍‬ .0002), intervention to treat unilateral renal artery stenosis (OR, 3.8; 95% CI, 0.8-16.6; P ‫؍‬ .05), and level of baseline Cr (OR, 3.0; 95% CI, 1.0-4.0; P ‫؍‬ .04). Progression to dialysis occurred in 16 (17%) patients. Dialysis-free survival at 5 years was 50%, and overall actuarial survival at 5 years was 59%. Predictors of progression to dialysis during follow-up included treatment of complete renal artery occlusion (OR, 6.2; 95% CI, 1.3-29.5; P ‫؍‬ .02), early failure of RAR (OR, 3.1; 95% CI, 0.7-14.2; P ‫؍‬ .04) and baseline Cr (OR, 2.9; 95% CI, 1.3-6.1; P ‫؍‬ .006). Conclusion: Long-term clinical success in the preservation of renal function, noted in 70% of patients, can be predicted by the initial response to RAR and by anatomic factors, in particular, bilateral repair. While extreme (mean Cr >3.2 mg/dL) renal dysfunction generally is predictive of poor long-term outcome, a subset of patients will experience favorable results, even to the extent of rescue from dialysis. These results may facilitate clinical decision making in the application of RAR for renal function salvage.

Annals of Surgery, Oct 1, 2010

Prospective trials have shown improved perioperative outcomes with endovascular repair of thoraci... more Prospective trials have shown improved perioperative outcomes with endovascular repair of thoracic aortic (TEVAR) pathologies compared with conventional surgery (OPEN). There are no long-term population data detailing the impact of TEVAR on practice patterns and results of treatment of descending thoracic aortic pathology (DTA), which are the goal of this study. All procedures performed on the DTA captured in the Medicare database from 2004 to 2007 were identified by ICD-9 codes and stratified into OPEN and TEVAR cohorts. Outcomes included perioperative mortality (χ(2)) and 5-year actuarial survival. There were 11,166 patients identified (4838 [43%] TEVAR vs. 6328 [57%] OPEN) with 7247 (65%) nonruptured, degenerative thoracic aortic aneurysms (TAA), 2701 (24%) descending aortic dissections, 1033 (9%) thoracic aortic ruptures, and 185 (2%) traumatic aortic tears. The distribution of cases changed significantly during the study period (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;lt; 0.0001) with an increase in TEVAR, decrease in OPEN, and increase in total cases over time (). The perioperative mortality was lower in the TEVAR group for the entire population (360 [7.4%] TEVAR vs. 1175 [18.5%] OPEN, 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;lt; 0.0001), and for the individual pathologies: TAA (182/3529 [5%] TEVAR vs. 451/3718 [12%] OPEN, 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;lt; 0.001), dissections (76/833 [9%] TEVAR vs. 399/1868 [21%] OPEN, 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;lt; 0.001) and ruptures (87/368 [24%] TEVAR vs. 298/665 [45%] OPEN, 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;lt; 0.0001). The Kaplan-Meier curve significantly favored TEVAR for the entire cohort because of the early mortality of the OPEN cohort but the curves converged by 5 years. The 5-year survival by indication was: entire population (53.4% TEVAR vs. 53.3% OPEN, 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;lt; 0.0001), TAA (55.8% TEVAR vs. 59.7% OPEN, P = 0.84), dissection (58.2% TEVAR vs. 50.6% OPEN, 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;lt; 0.0001), ruptures (23.3% TEVAR vs. 25.3% OPEN, P = 0.001), and trauma (62.9% TEVAR vs. 50.9% OPEN, P = 0.12). There has been a significant increase in the use of TEVAR for management of diseases of the DTA. TEVAR offers a significant perioperative survival advantage when compared with OPEN regardless of the indication for repair. However, in the Medicare population, the 5-year survival is similar between the 2 cohorts.

Catheterization and Cardiovascular Interventions, Nov 3, 2010

for the EMPiRE Clinical Study Investigators Background: Each of the embolic protection devices us... more for the EMPiRE Clinical Study Investigators Background: Each of the embolic protection devices used in carotid artery stenting (CAS) has advantages and disadvantages. The prospective, multicenter, single-arm EMPiRE Clinical Study investigated a proximally placed device (GORE Flow Reversal System) that provides distal neuroprotection during CAS by reversing blood flow in the internal carotid artery, thereby directing emboli away from the brain. Methods: The study evaluated 30-day outcomes in 245 pivotal high-surgical-risk patients (mean age, 70 years; 32% symptomatic; 16% !80-years old) with carotid stenosis who underwent CAS using the flow reversal system. The primary endpoint was a major adverse event (MAE; stroke, death, myocardial infarction, or transient ischemic attack) within 30 days of CAS. The MAE rate was compared with an objective performance criterion (OPC) derived from CAS studies that included embolic protection. Results: The MAE rate was 4.5% (11 patients; P 5 0.002 compared with the OPC). The stroke and death rate was 2.9%. No patient had a major ischemic stroke. Six patients (2.4%) had intolerance to flow reversal. The death and stroke rates in the symptomatic, asymptomatic, and octogenarian subgroups were 2.6, 3, and 2.6%, respectively, meeting American Heart Association guidelines for carotid endarterectomy. Conclusion: The stroke and death rate in this study was among the lowest in CAS trials. The results indicate that the flow reversal system is safe and effective when used for neuroprotection during CAS and that it provides benefits in a broad patient population.

Carolina Digital Repository (University of North Carolina at Chapel Hill), 2008

Objective: This report summarizes the 30-day and 12-month results of endovascular treatment using... more Objective: This report summarizes the 30-day and 12-month results of endovascular treatment using the Medtronic Vascular Talent Thoracic Stent Graft System (Medtronic Vascular, Santa Rosa, Calif) for patients with thoracic aortic aneurysms (TAA) who are considered candidates for open surgical repair. Methods: The study was a prospective, nonrandomized, multicenter, pivotal trial conducted at 38 sites. Enrollment occurred between December 2003 and June 2005. Standard follow-up interval examinations were prescribed at 1 month, 6 months, 1 year, and annually thereafter. These endovascular results were compared with retrospective open surgical data from three centers of excellence. Results: The Evaluation of the Medtronic Vascular Talent Thoracic Stent Graft System for the Treatment of Thoracic Aortic Aneurysms (VALOR) trial enrolled 195 patients, and 189 were identified as retrospective open surgical subjects. Compared with the open surgery group, the VALOR test group had similar age and sex distributions, but had a smaller TAA size. Patients received a mean number of 2.7 ؎ 1.3 stent graft components. The diameters of 25% of the proximal stent graft components implanted were <26 mm or >40 mm. Left subclavian artery revascularization was performed before the initial stent graft procedure in 5.2% of patients. Iliac conduits were used in 21.1% of patients. In 33.5% of patients, the bare spring segment of the most proximally implanted device was in zones 1 or 2 of the aortic arch. In 194 patients (99.5%), vessel access and stent graft deployment were successful at the intended site. The 30-day VALOR results included perioperative mortality, 2.1%; major adverse advents, 41%; incidence of paraplegia, 1.5%; paraparesis, 7.2%; and stroke, 3.6%. The 12-month VALOR results included all-cause mortality, 16.1%; aneurysm-related mortality, 3.1%; conversion to open surgery, 0.5%; target aneurysm rupture, 0.5%; stent graft migration >10 mm, 3.9%; endoleak (12.2%), stent graft patency, 100%; stable or decreasing aneurysm diameter, 91.5%; and loss of stent graft integrity, four patients. No deployment-related events or perforation of the aorta by a graft component occurred. The Talent Thoracic Stent Graft showed statistically superior performance with respect to acute procedural outcomes (P < .001), 30-day major adverse events (41% vs 84.4%, P < .001), perioperative mortality (2% vs 8%, P < .01), and 12-month aneurysm-related mortality (3.1% vs 11.6%, P < .002) vs open surgery. Conclusions: The pivotal VALOR 12-month trial results demonstrate that the Medtronic Talent Thoracic Stent Graft System is a safe and effective endovascular therapy as an alternative to open surgery in patients with TAA who were considered candidates for open surgical repair.

Carolina Digital Repository (University of North Carolina at Chapel Hill), 2012

Objective: We report the 5-year outcomes of thoracic endovascular aneurysm repair (TEVAR) using t... more Objective: We report the 5-year outcomes of thoracic endovascular aneurysm repair (TEVAR) using the Medtronic Vascular Talent Thoracic Stent Graft System (Medtronic Vascular, Santa Rosa, Calif) in patients considered low or moderate risk for open surgical repair. Methods: The Evaluation of the Medtronic Vascular Talent Thoracic Stent Graft System for the Treatment of Thoracic Aortic Aneurysms (VALOR) trial was a prospective, nonrandomized, multicenter, pivotal study conducted at 38 U.S. sites. Between December 2003 and June 2005, VALOR enrolled 195 patients who were low or moderate risk (0, 1, and 2) per the modified Society for Vascular Surgery and American Association for Vascular Surgery criteria. The patients had fusiform thoracic aortic aneurysms (TAAs) and/or focal saccular TAAs/penetrating atherosclerotic ulcers. Standard follow-up interval examinations were conducted at 1 month, 6 months, 1 year, and annually thereafter. Results: Over the 5-year follow-up, 76 deaths occurred (43.9%). Freedom from all-cause mortality was 83.9% at 1 year and 58.5% at 5 years. Most deaths were due to cardiac, pulmonary or cancer-related causes. Freedom from aneurysm-related mortality (ARM) was 96.9% at 1 year and 96.1% at 5 years. There was only 1 case of ARM after the first year of follow-up. Over the 5-year follow-up period, four patients were converted to open surgery and four patients experienced aneurysm rupture. The 5-year freedom from aneurysm rupture was 97.1% and the 5-year freedom from conversion to surgery was 97.1%. The incidence of stent graft migration (>10 mm) was <1.8% in each year of follow-up. The rate of type I endoleak was 4.6% at 1 month, 6.3% from 1 month to 1 year, and 3.8% during year 5. The rate of type III endoleak was 1.3% at 1 month, 1.9% from 1 month to 1 year, and 1.9% during year 5. Through 5 years, 28 patients (14.4%) underwent 31 additional endovascular procedures on the original target lesion. The 5-year freedom from secondary endovascular procedures was 81.5%. Conclusions: Through 5-year follow-up in patients who were candidates for open surgical repair, TEVAR using the Talent Thoracic Stent Graft System has demonstrated sustained protection from ARM, aneurysm rupture, and conversion to surgery, and durable stent graft performance. Close patient follow-up remains essential after TEVAR.

Journal of Vascular Surgery, Sep 1, 2013

We performed a cost-effectiveness analysis comparing SE and ilio-femoral PS with a baseline strat... more We performed a cost-effectiveness analysis comparing SE and ilio-femoral PS with a baseline strategy of nonsupervised exercise (NSE). Estimates for costs and outcomes were obtained from the medical literature (Table) and the Bureau of Labor Statistics. Costs were adjusted to 2012 US Dollars. Effectiveness was measured as the maximum walking distance (MWD) in meters by treadmill testing performed at 1-year. The primary endpoint was cost-effectiveness measured in dollars per meter walked. Because of a 1-year time horizon, discounting was not used.

Journal of Endovascular Therapy, Feb 1, 2009

Several challenges exist with respect to training the current and next generation of vascular spe... more Several challenges exist with respect to training the current and next generation of vascular specialists. Current advances in technology have led to changes in the length and type of training required to master new endovascular techniques. At the same time, the number of open surgical cases being provided to trainees may not be sufficient to allow them to manage complex open procedures. This growth is occurring at a time when increased external pressures are being applied to shorten training programs. Finally, the next generation of vascular specialists will come from medical students who are accruing a large educational debt during their course of training. Vascular specialists outside the US have already begun to successfully deal with many of these issues, and insight can be gained from their successes and difficulties. In this article, we review the current status of training for vascular and endovascular specialists and discuss the need for changes in current US training paradigms. While this will touch on initiatives in other specialties, including cardiology, vascular medicine, and interventional and neuroradiology, we will focus primarily on changes that are occurring with respect to the training of surgical specialists who manage vascular disease.

Annals of Vascular Surgery, 2013

Use of inferior vena cava filters (IVCFs) has become more prevalent for the prevention of venous ... more Use of inferior vena cava filters (IVCFs) has become more prevalent for the prevention of venous thromboembolism in part due to their ease of deployment and retrieval. Nonthrombotic complications of IVCFs are unusual but have been described. This study characterizes this cohort of patients and elucidates their clinical outcome. Between January 1, 2006 and December 31, 2011, six patients were identified with nonthrombotic symptoms attributed to their IVCF. Symptoms included abdominal/back pain, hypertension from renal artery compression, and hydroureter from ureteral compression. The average age of the patients was 38.8 years (range 21 to 71 years) and all were female. Indication for IVCF placement included deep vein thrombosis (n = 2), deep vein thrombosis with pulmonary embolism (n = 1), and perioperative prophylaxis (n = 3). Filter types included the Ninitol Bard G2 (n = 3), Cook Celect (n = 1), Gunther Tulip (n = 1), and ALN (n = 1). The median time from IVCF placement to retrieval was 285 days (range 20 to 2091 days). At presentation, all IVCFs were tilted and had struts penetrating through the vena cava wall. Every IVCF was successfully removed: four by endovascular approach and two by open surgery. All patients had complete resolution of symptoms and there were no procedural complications. Symptomatic IVCFs occur in female patients, and are always associated with device strut erosion outside the inferior vena cava. Successful retrieval can be safely achieved by an endovascular or open surgical technique, resulting in symptom resolution.

Carolina Digital Repository (University of North Carolina at Chapel Hill), 2009

Objective: Thoracic endovascular aortic repair (TEVAR) is applicable to a spectrum of thoracic ao... more Objective: Thoracic endovascular aortic repair (TEVAR) is applicable to a spectrum of thoracic aortic pathology with half of the procedures performed worldwide for indications other than degenerative aneurysm of the descending thoracic aorta (DTA). This multicenter, prospective study queried perioperative and one-year results of TEVAR using the commercially available GORE TAG device, in the treatment of acute complicated Type B dissection (cTBD), traumatic aortic tear (TT), and ruptured degenerative aneurysm (RDA) of the DTA. Methods: This prospective, non-randomized, literature controlled study included 59 patients; cTBD, n ‫؍‬ 19; RDA, n ‫؍‬ 20; TT, n ‫؍‬ 20. The primary end-point was the composite of death and total paraplegia in subjects at < 30 days post-treatment compared with a cohort from current literature. Secondary end-points included adverse events related to device, procedural and systemic complications, and one-year survival. Results: All 59 patients had successful endoprosthesis deployment. Fifteen of 19 (79%) patients in the cTBD group had either rupture or malperfusion syndromes at presentation. Combined 30-day mortality/paraplegia rate was 13.6% (8/59), with seven (11.9%) deaths (cTBD [3], RDA [3] and TT [1]) and 1 (TT, 1.7%) case of paraplegia. The primary end-point for the TEVAR cohort was significantly lower (P ‫؍‬ .008) when compared with a composite literature control of 800 patients (combined 30-day mortality/paraplegia of 29.6%). Thirty-day complications of any nature occurred in 48 (81%) patients; 11 (18.6%) were device related, and 43 (73%) experienced one or more systemic adverse events. Six (10%) patients required additional TEVAR implantations and 3 (5%) patients (one in each pathology group) required conversion to open surgery. Seventeen (29%) patients had endoleaks of any kind or degree through 30 days; cTBD (7), TT (2), RDA (8). Nine patients (15.3%) had perioperative strokes with two resultant deaths. During mean follow-up time of 409 ؎ 309 days, an additional 12 patients died, one patient required open conversion (cTBD), and two patients had major device related events. Actuarial survival at one year was 66% (range, 52%-77%) for the entire cohort; (cTBD) 79% (range, 53%-92%), (TT) 79% (range, 53%-92%) and (RDA) 37% (range, 16%-59%). On regression analysis, age at treatment (1.05 [range, 1.01-1.09]; P ‫؍‬ .008) and chronic obstructive pulmonary disease (COPD) (4.3 [range, 1.3-14.4]; P ‫؍‬ .02) were predictive of death at one year. Conclusion: This study confirmed treatment advantages for TEVAR for thoracic aortic catastrophes when compared with literature-based results of open repair. One-year treatment results indicate a low incidence of graft-related complications. TEVAR is the preferred initial treatment for the DTA catastrophes studied herein.

Journal of Vascular Surgery, Jun 1, 2019

no cases of postprocedural access site bleeding, hematoma, pseudoaneurysm, vascular injury, intra... more no cases of postprocedural access site bleeding, hematoma, pseudoaneurysm, vascular injury, intraoperative arrhythmia, arteriovenous fistula formation, or infection. Conclusions: TRA is a feasible and low-risk alternative for endovascular intervention in the trauma patient. It yields good technical success with low morbidity. Although larger studies are needed to establish the full efficacy of TRA at the multi-institutional level, this single-institution study demonstrates the legitimacy of an alternative means for endovascular intervention in the trauma patient.

Journal of The American College of Surgeons, Sep 1, 2014

Stroke, Feb 1, 2012

Background: Cerebral hyperperfusion syndrome (CHS) is a well documented complication of carotid e... more Background: Cerebral hyperperfusion syndrome (CHS) is a well documented complication of carotid endarterecomy (CEA), yet prior research has been limited to small case series and retrospective analyses, or studies using radiographic rather than clinical definitions. Methods: A prospective, independent monitoring system was implemented to monitor CEA outcomes at a major academic medical center. Independent, trained monitors from the neurology department examined all patients undergoing CEA both preoperatively and postoperatively at 24 hours and 30 days. Data were collected on patient demographics, medical history, and procedural and anatomical variables. Clinical variables were analyzed to identify risk factors for CHS, which was defined as cases with postoperative development of a severe headache, new neurological deficits without infarction, seizure or intracerebral hemorrhage. Results: Between 2008 and 2010, 832 CEA were monitored and CHS occurred in 14 (1.7%), including seizures in 5 (0.6%) subjects and intracerebral hemorrhage in 4 (0.5%). Univariate analysis identified a history of dyslipidemia, degree of ipsilateral stenosis and urgent CEA (performed during hospitalization for a symptomatic ipsilateral stroke, TIA or amaurosis fugax) as potential risks for CHS (all p&lt;0.2), whereas age, sex, race, hypertension, diabetes, smoking, degree of contralateral stenosis, operative time, presence of intraoperative EEG slowing, history of prior CEA or carotid stent and time from prior carotid interventions were not significant. Multivariable analysis confirmed the risk association between urgent CEA and CHS (p=0.015) but not dyslipidemia (p=0.084) or degree of ipsilateral stenosis (p=0.118). Surgical indications in urgent CEA patients who developed CHS were amaurosis fugax (1), TIA (3) and stroke (5). Conclusions: Independent, prospective monitoring of a large cohort of CEA cases identified a brief time interval between ischemic symptoms and endarterectomy as the clearest risk factor for CHS, with dyslipidemia and a high degree of ipsilateral carotid stenosis as possible contributory risks. Occurrence of CHS in patients undergoing urgent CEA does not appear to be limited to those with large strokes.

Journal of Vascular Surgery, Apr 1, 2003

Annals of Vascular Surgery, Mar 1, 2022

OBJECTIVES Unlike periprocedural Type 1A endoleaks, late appearing proximal endoleaks have been p... more OBJECTIVES Unlike periprocedural Type 1A endoleaks, late appearing proximal endoleaks have been poorly described. METHODS We studied all elective EVAR from 2010-2018 in a single institution. Late endoleaks were defined as those appearing after one year. We used Cox regression to study factors associated with late Type 1A endoleaks and survival. RESULTS Of 477 EVAR during the study period, 411 (86%) had follow-up imaging, revealing 24 Type 1A endoleaks; 4 early and 20 late. Freedom from Type 1A endoleaks was 99%, 92% and 81% at 1, 5 and 8 years with a median time to occurrence of 2.5 years (.01-8.2 years). On completion angiogram, only 10% of patients with a late Type 1A had a proximal endoleak, and 60% had no endoleak. Only 21% of late Type 1As were diagnosed on routine one-year CT angiogram, but 79% had stable or expanding sacs. Two thirds (65%) of the patients eventually diagnosed with late Type 1A endoleaks had previously been treated for other endoleaks, mostly Type 2 (10/13). Age (HR 1.07/year [1.02-1.12], P=.01), neck diameter >28mm (HR 3.5 [1.2-10.3], P=.02), neck length <20mm (HR 3.0 [1.1-8.6], P=.04), and neck angle>60 degrees (HR 3.4 [1.5-7.9], P=.004) were associated with higher rates of Type 1A endoleak, but not female sex, endograft, or the use of suprarenal fixation. Two patients had proximal degeneration and 5 experienced graft migration. There were two ruptures (10%), and 13 patients underwent repair with 5 open conversions. Median survival after late Type 1A repair was 6.6 years (0-8.4 years). CONCLUSION Late appearing Type 1A endoleaks have a high rate of rupture and present significant diagnostic and management challenges. Careful surveillance is needed in patients with hostile neck anatomy and those who undergo intervention for other endoleaks. Adverse neck anatomy may be better suited for open repair or fenestrated/branched devices rather than conventional EVAR.

The New England Journal of Medicine, Jul 28, 2011

Pr e sen tat ion of C a se Dr. Britta Panda (Obstetrics and Gynecology): A 40-year-old woman was ... more Pr e sen tat ion of C a se Dr. Britta Panda (Obstetrics and Gynecology): A 40-year-old woman was seen by the maternal-fetal medicine service at this hospital at 22 weeks 2 days' gestation because of placenta previa and placenta accreta. Beginning at 12 weeks 1 day's gestation, the patient had received routine prenatal care at a health center affiliated with this hospital. She was gravida 5, para 4, and had had normal vaginal deliveries at term with her first two pregnancies, 16 and 9 years earlier. Seven years earlier, a cesarean section had been performed at term for a breech presentation during labor. An initial low transverse uterine incision was extended into a high vertical incision because of difficulty extracting the fetus. The patient's hematocrit had decreased from 33.6% to 17.6% post partum (reference range for nonpregnant women, 36.0 to 46.0). Five years before this admission, a cesarean section, with a low transverse incision, was performed electively at term; the postpartum hematocrit was 28.9%. A skin test for tuberculosis had reportedly been positive 8 years earlier, with a normal chest radiograph; isoniazid had been administered for 6 months. The patient had iron-deficiency anemia for which iron supplements had been prescribed but discontinued because of gastrointestinal intolerance. She had had varicella-zoster virus infection, and screening for rubella antibody had been positive. She was taking only prenatal multivitamins and had no known allergies. She was born in a Caribbean country, lived with her husband and children, and worked in a health care field. She declined transfusions of all blood products because of her religious beliefs. Her husband, also a health care worker, did not share these beliefs. She did not drink alcohol, smoke cigarettes, or use illicit drugs. Her mother had hypertension; her father had had hypertension and epilepsy and had died at the age of 70 years. Her sister had sickle cell trait, and the patient's children and half-siblings were well. On examination at the initial prenatal visit, the weight was 60.3 kg and the blood pressure 100/58 mm Hg; the remainder of the examination was consistent with the gestational stage and was otherwise normal. The hematocrit was 29.1%

Journal of Vascular Surgery, Sep 1, 1996

The aim of this project was to evaluate the feasibility of aortoscopy for guidance of endoluminal... more The aim of this project was to evaluate the feasibility of aortoscopy for guidance of endoluminal aortic procedures and to determine whether aortoscopy has advantages over fluoroscopy in a pig model. Methods: To establish feasibility aortoscopic guidance was used for making endoluminal aortic measurements, cannulating small arteries for arteriograpy, and placing intraaortic stents and grafts in 11 pigs. To compare aortoscopy and fluoroscopy measurements were made and stents were placed by a surgeon using only aortoscopic guidance in 10 pigs and by an interventional radiologist using only fluoroscopic guidance in 10 pigs. Postmortem dissections were performed to determine measurement and device placement accuracy. Results: In the feasibility study aortoscopic measurements differed from postmortem measurements by a mean distance (+SD) of 1.2 + 0.2 nun. Stents and grafts were placed a mean of 2.3 + 1.9 mm distal to the most inferior renal artery with no stent covering an orifice. All attempts at cannulating spinal arteries greater than 2 mm in diameter were successful. In the comparison of aortoscopic and fluoroscopic guidance, fluoroscopic measurements differed from postmortem measurements by 2.6 _+ 2.4 mm (p = 0.223). Stents placed with aortoscopic guidance were 1.1 + 1.3 mm distal to the most inferior renal artery, whereas stents placed with fluoroscopic guidance were 3.4 + 2.5 mm distal to the most inferior renal artery (p = 0.019). Conclusions: These resnlts demonstrate that aortoscopy is a usehtl guidance system for endoluminal aortic procedures and may have advantages over fluoroscopy alone. (J Vase Surg 1996;24:439-48.) Recent advances in catheter-based technology have made possible a variety of minimally invasive approaches for the treatment of aortic aneurysmal and occlusive disease. Long-term results are becoming available for endoluminal aortic aneurysm exclusion, and the complications most commonly reported are leakage from incomplete exclusion, which has caused aneurysm rupture and death, and inability to properly position the deployed graft. 1-~ Endoluminal aortic aneurysm exclusion requires an adequate proximal aneurysm neck for fixation of the endoluminal graft. 6