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Papers by Ralph Stewart

Research paper thumbnail of Post-operative aspartate aminotransferase levels independently predict mortality after isolated coronary artery bypass grafting

Ijc Metabolic Endocrine, Jan 10, 2015

ABSTRACT Since troponins have become widely available, the roles of other less specific biomarker... more ABSTRACT Since troponins have become widely available, the roles of other less specific biomarkers for myocardial necrosis following coronary artery bypass grafting (CABG) have been seldom studied. Aspartate aminotransferase (AST) may not only be released from the heart but also from the liver or skeletal muscle. We assessed whether post-operative AST levels were associated with mortality and morbidity after contemporary (CABG).

Research paper thumbnail of Maori have worse outcomes after coronary artery bypass grafting than Europeans in New Zealand

The New Zealand Medical Journal, 2013

Aims Disparities for Māori exist in New Zealand for cardiovascular risk factors, events and acces... more Aims Disparities for Māori exist in New Zealand for cardiovascular risk factors, events and access to revascularisation. We compared characteristics and outcomes of coronary artery bypass grafting (CABG) between Māori and Europeans in New Zealand.

Research paper thumbnail of Regional variations in treatments and outcomes of reinfarction in the HERO-2 trial

J Amer Coll Cardiol, 2003

Research paper thumbnail of Variation in and prognostic importance of troponin T measured using a high-sensitivity assay in clinically stable haemodialysis patients

Clinical Kidney Journal, 2012

Background. A recently introduced high-sensitivity assay can measure troponin T (hsT) at low leve... more Background. A recently introduced high-sensitivity assay can measure troponin T (hsT) at low levels with greater precision than the fourth generation troponin T assay. As most patients with end-stage renal failure (ESRF) may have elevated hsT levels, data on biological variability and the impact of haemodialysis are needed for clinical interpretation of results.

Research paper thumbnail of Text Message and Internet Support for Coronary Heart Disease Self-Management: Results From the Text4Heart Randomized Controlled Trial

Journal of Medical Internet Research, 2015

Mobile technology has the potential to deliver behavior change interventions (mHealth) to reduce ... more Mobile technology has the potential to deliver behavior change interventions (mHealth) to reduce coronary heart disease (CHD) at modest cost. Previous studies have focused on single behaviors; however, cardiac rehabilitation (CR), a component of CHD self-management, needs to address multiple risk factors. The aim was to investigate the effectiveness of a mHealth-delivered comprehensive CR program (Text4Heart) to improve adherence to recommended lifestyle behaviors (smoking cessation, physical activity, healthy diet, and nonharmful alcohol use) in addition to usual care (traditional CR). A 2-arm, parallel, randomized controlled trial was conducted in New Zealand adults diagnosed with CHD. Participants were recruited in-hospital and were encouraged to attend center-based CR (usual care control). In addition, the intervention group received a personalized 24-week mHealth program, framed in social cognitive theory, sent by fully automated daily short message service (SMS) text messages and a supporting website. The primary outcome was adherence to healthy lifestyle behaviors measured using a self-reported composite health behavior score (≥3) at 3 and 6 months. Secondary outcomes included clinical outcomes, medication adherence score, self-efficacy, illness perceptions, and anxiety and/or depression at 6 months. Baseline and 6-month follow-up assessments (unblinded) were conducted in person. Eligible patients (N=123) recruited from 2 large metropolitan hospitals were randomized to the intervention (n=61) or the control (n=62) group. Participants were predominantly male (100/123, 81.3%), New Zealand European (73/123, 59.3%), with a mean age of 59.5 (SD 11.1) years. A significant treatment effect in favor of the intervention was observed for the primary outcome at 3 months (AOR 2.55, 95% CI 1.12-5.84; P=.03), but not at 6 months (AOR 1.93, 95% CI 0.83-4.53; P=.13). The intervention group reported significantly greater medication adherence score (mean difference: 0.58, 95% CI 0.19-0.97; P=.004). The majority of intervention participants reported reading all their text messages (52/61, 85%). The number of visits to the website per person ranged from zero to 100 (median 3) over the 6-month intervention period. A mHealth CR intervention plus usual care showed a positive effect on adherence to multiple lifestyle behavior changes at 3 months in New Zealand adults with CHD compared to usual care alone. The effect was not sustained to the end of the 6-month intervention. A larger study is needed to determine the size of the effect in the longer term and whether the change in behavior reduces adverse cardiovascular events. ACTRN 12613000901707; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=364758&isReview=true (Archived by WebCite at http://www.webcitation.org/6c4qhcHKt).

Research paper thumbnail of Importance of Angina in Patients With Coronary Disease, Heart Failure, and Left Ventricular Systolic Dysfunction

Journal of the American College of Cardiology, 2015

Patients with left ventricular (LV) systolic dysfunction, coronary artery disease (CAD), and angi... more Patients with left ventricular (LV) systolic dysfunction, coronary artery disease (CAD), and angina are often thought to have a worse prognosis and a greater prognostic benefit from coronary artery bypass graft (CABG) surgery than those without angina. This study investigated: 1) whether angina was associated with a worse prognosis; 2) whether angina identified patients who had a greater survival benefit from CABG; and 3) whether CABG improved angina in patients with LV systolic dysfunction and CAD. We performed an analysis of the STICH (Surgical Treatment for Ischemic Heart Failure) trial, in which 1,212 patients with an ejection fraction ≤35% and CAD were randomized to CABG or medical therapy. Multivariable Cox and logistic models were used to assess long-term clinical outcomes. At baseline, 770 patients (64%) reported angina. Among patients assigned to medical therapy, all-cause mortality was similar in patients with and without angina (hazard ratio [HR]: 1.05; 95% confidence interval [CI]: 0.79 to 1.38). The effect of CABG was similar whether the patient had angina (HR: 0.89; 95% CI: 0.71 to 1.13) or not (HR: 0.68; 95% CI: 0.50 to 0.94; p interaction = 0.14). Patients assigned to CABG were more likely to report improvement in angina than those assigned to medical therapy alone (odds ratio: 0.70; 95% CI: 0.55 to 0.90; p < 0.01). Angina does not predict all-cause mortality in medically treated patients with LV systolic dysfunction and CAD, nor does it identify patients who have a greater survival benefit from CABG. However, CABG does improve angina to a greater extent than medical therapy alone. (Comparison of Surgical and Medical Treatment for Congestive Heart Failure and Coronary Artery Disease [STICH]; NCT00023595).

Research paper thumbnail of Biomarkers in stable coronary heart disease, their modulation and cardiovascular risk: The LIPID biomarker study

International journal of cardiology, Jan 16, 2015

In patients with stable coronary heart disease (CHD), we aimed to assess 1. the prognostic power ... more In patients with stable coronary heart disease (CHD), we aimed to assess 1. the prognostic power of biomarkers reflecting haemodynamics, micronecrosis, inflammation, coagulation, lipids, neurohumoral activity, and renal function; 2. whether changes in concentrations of these biomarkers over 12months affected subsequent CHD risk; and 3. whether pravastatin modified the change in biomarker concentrations and this influenced the risk of future events. In the LIPID study, 9014 patients were randomised to pravastatin 40mg or placebo 3-36months after an acute coronary syndrome. Eight biomarkers were measured at baseline (n=7863) and 12months later (n=6434). During a median of 6.0 (IQR 5.5-6.5) years follow-up, 1100 CHD-related deaths and nonfatal myocardial infarctions occurred, 694 after biomarker measurement at 12months. Baseline BNP, CRP, cystatin C, D-dimer, midregional pro-adrenomedullin, and sensitive troponin I predicted recurrent CHD events. In a multivariable model, sensitive tro...

Research paper thumbnail of Acceptability of a Mobile Health Exercise-Based Cardiac Rehabilitation Intervention

Journal of Cardiopulmonary Rehabilitation and Prevention, 2015

Mobile technologies (mHealth) have recently been used to deliver behavior change interventions; h... more Mobile technologies (mHealth) have recently been used to deliver behavior change interventions; however, few have investigated the application of mHealth for treatment of ischemic heart disease (IHD). The Heart Exercise And Remote Technologies trial examined the effectiveness of an mHealth intervention to increase exercise behavior in adults with IHD. As a part of this trial, a process evaluation was conducted. One hundred seventy-one adults with IHD were randomized to receive a 6-month mHealth intervention (n = 85) plus usual care or usual care alone (n = 86). The intervention delivered a theory-based, automated package of exercise prescription and behavior change text messages and a supporting Web site. Three sources of data were triangulated to assess intervention participant perceptions: (1) Web site usage statistics; (2) feedback surveys; and (3) semistructured exit interviews. Descriptive information from survey and Web data were merged with qualitative data and analyzed using a semantic thematic approach. At 24 weeks, all intervention participants provided Web usage statistics, 75 completed the feedback survey, and 17 were interviewed. Participants reported reading the text messages (70/75; 93%) and liked the content (55/75; 73%). The program motivated participants to exercise. Several suggestions to improve the program included further tailoring of the content (7/75; 7%) and increased personal contact (10/75; 13%). Adults with IHD were able to use an mHealth program and reported that text messaging is a good way to deliver exercise information. While mHealth is designed to be automated, programs might be improved if content and delivery were tailored to individual needs.

Research paper thumbnail of Growth Differentiation FACTOR-15 (GDF-15) for Prognostication of Outcomes in Stable Coronary Artery Disease: Experiences From the Stability Trial

Journal of the American College of Cardiology, 2015

Background: Evaluation of risk in stable coronary artery disease (CAD) is currently based on clin... more Background: Evaluation of risk in stable coronary artery disease (CAD) is currently based on clinical characteristics and biomarkers of dysglycemia, dyslipidemia, renal dysfunction, and inflammatory activity. In the STABILITY trial, treatment with darapladib, an inhibitor of lipoprotein-associated phospholipase A2, in 15,828 patients with stable CAD did not significantly reduce major adverse cardiovascular events (MACE=cardiovascular (CV) death, myocardial infarction (MI) or stroke) but reduced major coronary events (MCE=coronary death, MI, urgent coronary revascularization) by 10% compared to placebo (nominal p=0.045). We investigated the prognostic value of GDF-15, a biomarker of oxidative stress and cellular aging, on CV outcomes.

Research paper thumbnail of Lack of relationship between obesity and mortality or morbidity after coronary artery bypass grafting

The New Zealand medical journal, Jan 22, 2013

Obesity has significant adverse effects on cardiovascular health. Conflicting results have been r... more Obesity has significant adverse effects on cardiovascular health. Conflicting results have been reported regarding relationships between body mass index (BMI) and outcomes after coronary artery bypass grafting (CABG). We compared outcomes of CABG patients by BMI categories. Isolated CABG performed between July 2010-June 2012 at Auckland City Hospital were categorised into four groups of BMI ≤25 (normal), >25-30 (overweight), >30-35 (obese) and >35 kg/m² (morbidly obese) retrospectively for analyses. The four groups had 181(22.4%), 320 (39.6%), 205 (25.3%) and 103 (12.7%) patients respectively. Increasing BMI was associated with younger age (p<0.001) and increasing creatinine clearance (p<0.001). Obesity was associated with a higher proportion of patients of Maori or Pacific ethnicity and patients with more hypertension. Morbid obesity was associated with female sex, higher mean New Zealand Deprivation Index, diabetes, longer operation time and sternal wound infection....

Research paper thumbnail of Bias in the evaluation of effects of statins on mortality in patients with heart failure

Heart, lung & circulation, 2014

Research paper thumbnail of Higher mortality in women undergoing coronary artery bypass grafting

The New Zealand medical journal, 2013

While men have higher rates of cardiovascular disease, several studies report women having higher... more While men have higher rates of cardiovascular disease, several studies report women having higher mortality after cardiac surgery, reasons for which are unclear. We compared characteristics and outcomes of coronary artery bypass grafting (CABG) by sex. All patients undergoing isolated CABG during July 2010-June 2012 were grouped by sex for retrospective analyses. A total of 168 (20.5%) women and 650 (79.4%) men were included, followed-up for 1.4 plus or minus 0.6 years. Women were older (66.4 vs 64.0 years; p=0.007), with higher body mass index (30.1 vs 28.8 kg/m²; p=0.004), increased prevalence of hypertension (78.9% vs 67.8%; p=0.008), current smoking (20.2% vs 13.1%; p=0.027), chronic respiratory disease (22.6% vs 15.4%; p=0.028) and estimated glomerular filtration rate (74 vs 81 ml/min/1.73 m²; p=0.007). Women had less grafts performed (3.1 vs 3.3; p=0.014) and less use of radial grafts (14.9% vs 25.2%; p=0.004). Female sex was independently associated with higher 30-day mortali...

Research paper thumbnail of Statins and n-3 fatty acids are the best lipid-lowering interventions for reducing mortality. Commentary

Evidence-based cardiovascular medicine, 2005

Research paper thumbnail of High negative appendectomy rates are no longer acceptable

American journal of surgery, 1997

A 10% to 20% negative appendectomy rate has been accepted in order to minimize the incidence of p... more A 10% to 20% negative appendectomy rate has been accepted in order to minimize the incidence of perforated appendicitis with its increased morbidity. We reviewed our experience with appendicitis in order to determine the incidence of negative appendectomies and perforation, and the role of delay in diagnosis or treatment. We reviewed 659 appendectomies performed over a 12-month period. Incidental and pediatric appendectomies were excluded. Seventy-five percent of patients were male and 25% female. Nine percent had negative appendectomies and 28% had perforated appendicitis. Perforated appendicitis resulted in increased morbidity and length of stay. Delay in presentation greater than 12 hours after the onset of symptoms significantly increased the perforation rate. In-hospital delay did not affect perforation rate. We have achieved a negative appendectomy rate lower than that in other reported series, while maintaining an acceptable perforation rate. In the majority of patients, perf...

Research paper thumbnail of Secondary prevention and risk factor target achievement in a global, high-risk population with established coronary heart disease: baseline results from the STABILITY study

European journal of preventive cardiology, 2013

There is limited contemporary data on achievement of risk factor goals for secondary prevention o... more There is limited contemporary data on achievement of risk factor goals for secondary prevention of cardiovascular (CV) disease from countries in many regions of the world. This report describes the global and regional prevalence of CV risk factors and use of preventive medications at baseline in participants in the ongoing STabilization of Atherosclerotic plaque By Initiation of darapLadIb TherapY (STABILITY) trial. Detailed individual data on CV risk factors were obtained before randomization in 15,828 patients with chronic coronary heart disease (CHD) from 39 countries on five continents. Subjects had a history of myocardial infarction, prior coronary revascularization, or multi-vessel CHD without revascularization and at least one additional CV risk factor. The majority were taking a statin (97%), antiplatelet therapy (96%), beta-blocker (79%), or angiotensin converting enzyme inhibitor/angiotensin receptor blocker (77%). However, a large proportion of patients did not achieve gu...

Research paper thumbnail of New ST-depression: an under-recognized high-risk category of 'complete' ST-resolution after reperfusion therapy

European heart journal. Acute cardiovascular care, 2012

It is not known if there is an association between resolution of ST-elevation to ST-depression fo... more It is not known if there is an association between resolution of ST-elevation to ST-depression following fibrinolysis and 30-day mortality. In an ECG substudy of HERO-2, which compared bivalirudin to unfractionated heparin following streptokinase in 12,556 patients with ST-elevation myocardial infarction ECGs were recorded at baseline and at 60 minutes after commencing fibrinolysis. The main outcome measure was 30-day mortality. Using summed ST-segment elevation and five categories of changes in the infarct leads, further ST-elevation, 0-30% ST-resolution, >30-70% (partial) ST-resolution, >70% (complete) ST-resolution, and new ST-depression occurred in 21.7, 24.9, 36.8, 14.8, and 1.8% of patients, with 30-day mortality of 12.3, 11.7, 8.0, 4.2, and 8.1%, respectively. For the comparison of new ST-depression with complete ST-resolution and no ST-depression, p<0.01 with 24-hour mortality 4.5 vs. 1.3%, respectively (p=0.0003). Patients with new ST-depression had similar peak ca...

Research paper thumbnail of O047 Comparing Contemporary Coronary Artery Bypass Grafting Across Six Main Ethnic Groups of New Zealand: Another Example of Inequalities In Cardiovascular Disease

Research paper thumbnail of O220 Performance Of Euroscore I, Euroscore Ii And Society Of Thoracic Surgeon’S Risk Models To Predict Adverse Outcomes After Isolated Coronary Artery Bypass Grafting

Research paper thumbnail of PM225 Utility of High-Sensitivity Troponin To Diagnose Myocardial Infarction After Isolated Aortic Valve Replacement

Research paper thumbnail of Complex valve disease: pre-surgical functional capacity evaluation using peak oxygen consumption

The Journal of heart valve disease, 2009

Complex heart valve disease constitutes both mixed and multiple valve pathologies that coexist in... more Complex heart valve disease constitutes both mixed and multiple valve pathologies that coexist in a single heart. The chronicity of complex valve disease results in a slow decline in functional capacity. Currently, very few data exist relating to chronic complex valve disease. The clinical assessment of exertional dyspnea (NYHA class) is central to the decision to operate and predict a prognosis. Dyspnea causes significant functional limitations. Peak oxygen consumption (peak VO2) is the 'gold standard' of objectively measuring functional aerobic capacity, and is an important predictor of prognosis. The onset of dyspnea is the most common indication for valve surgery. The study aim, in patients with complex valve disease, was to: (i) objectively assess functional aerobic capacity using peak VO2; and (ii) compare the differences between NYHA classes I and II in relation to body composition, echocardiographic severity, and functional capacity A total of 45 patients with comple...

Research paper thumbnail of Post-operative aspartate aminotransferase levels independently predict mortality after isolated coronary artery bypass grafting

Ijc Metabolic Endocrine, Jan 10, 2015

ABSTRACT Since troponins have become widely available, the roles of other less specific biomarker... more ABSTRACT Since troponins have become widely available, the roles of other less specific biomarkers for myocardial necrosis following coronary artery bypass grafting (CABG) have been seldom studied. Aspartate aminotransferase (AST) may not only be released from the heart but also from the liver or skeletal muscle. We assessed whether post-operative AST levels were associated with mortality and morbidity after contemporary (CABG).

Research paper thumbnail of Maori have worse outcomes after coronary artery bypass grafting than Europeans in New Zealand

The New Zealand Medical Journal, 2013

Aims Disparities for Māori exist in New Zealand for cardiovascular risk factors, events and acces... more Aims Disparities for Māori exist in New Zealand for cardiovascular risk factors, events and access to revascularisation. We compared characteristics and outcomes of coronary artery bypass grafting (CABG) between Māori and Europeans in New Zealand.

Research paper thumbnail of Regional variations in treatments and outcomes of reinfarction in the HERO-2 trial

J Amer Coll Cardiol, 2003

Research paper thumbnail of Variation in and prognostic importance of troponin T measured using a high-sensitivity assay in clinically stable haemodialysis patients

Clinical Kidney Journal, 2012

Background. A recently introduced high-sensitivity assay can measure troponin T (hsT) at low leve... more Background. A recently introduced high-sensitivity assay can measure troponin T (hsT) at low levels with greater precision than the fourth generation troponin T assay. As most patients with end-stage renal failure (ESRF) may have elevated hsT levels, data on biological variability and the impact of haemodialysis are needed for clinical interpretation of results.

Research paper thumbnail of Text Message and Internet Support for Coronary Heart Disease Self-Management: Results From the Text4Heart Randomized Controlled Trial

Journal of Medical Internet Research, 2015

Mobile technology has the potential to deliver behavior change interventions (mHealth) to reduce ... more Mobile technology has the potential to deliver behavior change interventions (mHealth) to reduce coronary heart disease (CHD) at modest cost. Previous studies have focused on single behaviors; however, cardiac rehabilitation (CR), a component of CHD self-management, needs to address multiple risk factors. The aim was to investigate the effectiveness of a mHealth-delivered comprehensive CR program (Text4Heart) to improve adherence to recommended lifestyle behaviors (smoking cessation, physical activity, healthy diet, and nonharmful alcohol use) in addition to usual care (traditional CR). A 2-arm, parallel, randomized controlled trial was conducted in New Zealand adults diagnosed with CHD. Participants were recruited in-hospital and were encouraged to attend center-based CR (usual care control). In addition, the intervention group received a personalized 24-week mHealth program, framed in social cognitive theory, sent by fully automated daily short message service (SMS) text messages and a supporting website. The primary outcome was adherence to healthy lifestyle behaviors measured using a self-reported composite health behavior score (≥3) at 3 and 6 months. Secondary outcomes included clinical outcomes, medication adherence score, self-efficacy, illness perceptions, and anxiety and/or depression at 6 months. Baseline and 6-month follow-up assessments (unblinded) were conducted in person. Eligible patients (N=123) recruited from 2 large metropolitan hospitals were randomized to the intervention (n=61) or the control (n=62) group. Participants were predominantly male (100/123, 81.3%), New Zealand European (73/123, 59.3%), with a mean age of 59.5 (SD 11.1) years. A significant treatment effect in favor of the intervention was observed for the primary outcome at 3 months (AOR 2.55, 95% CI 1.12-5.84; P=.03), but not at 6 months (AOR 1.93, 95% CI 0.83-4.53; P=.13). The intervention group reported significantly greater medication adherence score (mean difference: 0.58, 95% CI 0.19-0.97; P=.004). The majority of intervention participants reported reading all their text messages (52/61, 85%). The number of visits to the website per person ranged from zero to 100 (median 3) over the 6-month intervention period. A mHealth CR intervention plus usual care showed a positive effect on adherence to multiple lifestyle behavior changes at 3 months in New Zealand adults with CHD compared to usual care alone. The effect was not sustained to the end of the 6-month intervention. A larger study is needed to determine the size of the effect in the longer term and whether the change in behavior reduces adverse cardiovascular events. ACTRN 12613000901707; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=364758&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;isReview=true (Archived by WebCite at http://www.webcitation.org/6c4qhcHKt).

Research paper thumbnail of Importance of Angina in Patients With Coronary Disease, Heart Failure, and Left Ventricular Systolic Dysfunction

Journal of the American College of Cardiology, 2015

Patients with left ventricular (LV) systolic dysfunction, coronary artery disease (CAD), and angi... more Patients with left ventricular (LV) systolic dysfunction, coronary artery disease (CAD), and angina are often thought to have a worse prognosis and a greater prognostic benefit from coronary artery bypass graft (CABG) surgery than those without angina. This study investigated: 1) whether angina was associated with a worse prognosis; 2) whether angina identified patients who had a greater survival benefit from CABG; and 3) whether CABG improved angina in patients with LV systolic dysfunction and CAD. We performed an analysis of the STICH (Surgical Treatment for Ischemic Heart Failure) trial, in which 1,212 patients with an ejection fraction ≤35% and CAD were randomized to CABG or medical therapy. Multivariable Cox and logistic models were used to assess long-term clinical outcomes. At baseline, 770 patients (64%) reported angina. Among patients assigned to medical therapy, all-cause mortality was similar in patients with and without angina (hazard ratio [HR]: 1.05; 95% confidence interval [CI]: 0.79 to 1.38). The effect of CABG was similar whether the patient had angina (HR: 0.89; 95% CI: 0.71 to 1.13) or not (HR: 0.68; 95% CI: 0.50 to 0.94; p interaction = 0.14). Patients assigned to CABG were more likely to report improvement in angina than those assigned to medical therapy alone (odds ratio: 0.70; 95% CI: 0.55 to 0.90; 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;lt; 0.01). Angina does not predict all-cause mortality in medically treated patients with LV systolic dysfunction and CAD, nor does it identify patients who have a greater survival benefit from CABG. However, CABG does improve angina to a greater extent than medical therapy alone. (Comparison of Surgical and Medical Treatment for Congestive Heart Failure and Coronary Artery Disease [STICH]; NCT00023595).

Research paper thumbnail of Biomarkers in stable coronary heart disease, their modulation and cardiovascular risk: The LIPID biomarker study

International journal of cardiology, Jan 16, 2015

In patients with stable coronary heart disease (CHD), we aimed to assess 1. the prognostic power ... more In patients with stable coronary heart disease (CHD), we aimed to assess 1. the prognostic power of biomarkers reflecting haemodynamics, micronecrosis, inflammation, coagulation, lipids, neurohumoral activity, and renal function; 2. whether changes in concentrations of these biomarkers over 12months affected subsequent CHD risk; and 3. whether pravastatin modified the change in biomarker concentrations and this influenced the risk of future events. In the LIPID study, 9014 patients were randomised to pravastatin 40mg or placebo 3-36months after an acute coronary syndrome. Eight biomarkers were measured at baseline (n=7863) and 12months later (n=6434). During a median of 6.0 (IQR 5.5-6.5) years follow-up, 1100 CHD-related deaths and nonfatal myocardial infarctions occurred, 694 after biomarker measurement at 12months. Baseline BNP, CRP, cystatin C, D-dimer, midregional pro-adrenomedullin, and sensitive troponin I predicted recurrent CHD events. In a multivariable model, sensitive tro...

Research paper thumbnail of Acceptability of a Mobile Health Exercise-Based Cardiac Rehabilitation Intervention

Journal of Cardiopulmonary Rehabilitation and Prevention, 2015

Mobile technologies (mHealth) have recently been used to deliver behavior change interventions; h... more Mobile technologies (mHealth) have recently been used to deliver behavior change interventions; however, few have investigated the application of mHealth for treatment of ischemic heart disease (IHD). The Heart Exercise And Remote Technologies trial examined the effectiveness of an mHealth intervention to increase exercise behavior in adults with IHD. As a part of this trial, a process evaluation was conducted. One hundred seventy-one adults with IHD were randomized to receive a 6-month mHealth intervention (n = 85) plus usual care or usual care alone (n = 86). The intervention delivered a theory-based, automated package of exercise prescription and behavior change text messages and a supporting Web site. Three sources of data were triangulated to assess intervention participant perceptions: (1) Web site usage statistics; (2) feedback surveys; and (3) semistructured exit interviews. Descriptive information from survey and Web data were merged with qualitative data and analyzed using a semantic thematic approach. At 24 weeks, all intervention participants provided Web usage statistics, 75 completed the feedback survey, and 17 were interviewed. Participants reported reading the text messages (70/75; 93%) and liked the content (55/75; 73%). The program motivated participants to exercise. Several suggestions to improve the program included further tailoring of the content (7/75; 7%) and increased personal contact (10/75; 13%). Adults with IHD were able to use an mHealth program and reported that text messaging is a good way to deliver exercise information. While mHealth is designed to be automated, programs might be improved if content and delivery were tailored to individual needs.

Research paper thumbnail of Growth Differentiation FACTOR-15 (GDF-15) for Prognostication of Outcomes in Stable Coronary Artery Disease: Experiences From the Stability Trial

Journal of the American College of Cardiology, 2015

Background: Evaluation of risk in stable coronary artery disease (CAD) is currently based on clin... more Background: Evaluation of risk in stable coronary artery disease (CAD) is currently based on clinical characteristics and biomarkers of dysglycemia, dyslipidemia, renal dysfunction, and inflammatory activity. In the STABILITY trial, treatment with darapladib, an inhibitor of lipoprotein-associated phospholipase A2, in 15,828 patients with stable CAD did not significantly reduce major adverse cardiovascular events (MACE=cardiovascular (CV) death, myocardial infarction (MI) or stroke) but reduced major coronary events (MCE=coronary death, MI, urgent coronary revascularization) by 10% compared to placebo (nominal p=0.045). We investigated the prognostic value of GDF-15, a biomarker of oxidative stress and cellular aging, on CV outcomes.

Research paper thumbnail of Lack of relationship between obesity and mortality or morbidity after coronary artery bypass grafting

The New Zealand medical journal, Jan 22, 2013

Obesity has significant adverse effects on cardiovascular health. Conflicting results have been r... more Obesity has significant adverse effects on cardiovascular health. Conflicting results have been reported regarding relationships between body mass index (BMI) and outcomes after coronary artery bypass grafting (CABG). We compared outcomes of CABG patients by BMI categories. Isolated CABG performed between July 2010-June 2012 at Auckland City Hospital were categorised into four groups of BMI ≤25 (normal), >25-30 (overweight), >30-35 (obese) and >35 kg/m² (morbidly obese) retrospectively for analyses. The four groups had 181(22.4%), 320 (39.6%), 205 (25.3%) and 103 (12.7%) patients respectively. Increasing BMI was associated with younger age (p<0.001) and increasing creatinine clearance (p<0.001). Obesity was associated with a higher proportion of patients of Maori or Pacific ethnicity and patients with more hypertension. Morbid obesity was associated with female sex, higher mean New Zealand Deprivation Index, diabetes, longer operation time and sternal wound infection....

Research paper thumbnail of Bias in the evaluation of effects of statins on mortality in patients with heart failure

Heart, lung & circulation, 2014

Research paper thumbnail of Higher mortality in women undergoing coronary artery bypass grafting

The New Zealand medical journal, 2013

While men have higher rates of cardiovascular disease, several studies report women having higher... more While men have higher rates of cardiovascular disease, several studies report women having higher mortality after cardiac surgery, reasons for which are unclear. We compared characteristics and outcomes of coronary artery bypass grafting (CABG) by sex. All patients undergoing isolated CABG during July 2010-June 2012 were grouped by sex for retrospective analyses. A total of 168 (20.5%) women and 650 (79.4%) men were included, followed-up for 1.4 plus or minus 0.6 years. Women were older (66.4 vs 64.0 years; p=0.007), with higher body mass index (30.1 vs 28.8 kg/m²; p=0.004), increased prevalence of hypertension (78.9% vs 67.8%; p=0.008), current smoking (20.2% vs 13.1%; p=0.027), chronic respiratory disease (22.6% vs 15.4%; p=0.028) and estimated glomerular filtration rate (74 vs 81 ml/min/1.73 m²; p=0.007). Women had less grafts performed (3.1 vs 3.3; p=0.014) and less use of radial grafts (14.9% vs 25.2%; p=0.004). Female sex was independently associated with higher 30-day mortali...

Research paper thumbnail of Statins and n-3 fatty acids are the best lipid-lowering interventions for reducing mortality. Commentary

Evidence-based cardiovascular medicine, 2005

Research paper thumbnail of High negative appendectomy rates are no longer acceptable

American journal of surgery, 1997

A 10% to 20% negative appendectomy rate has been accepted in order to minimize the incidence of p... more A 10% to 20% negative appendectomy rate has been accepted in order to minimize the incidence of perforated appendicitis with its increased morbidity. We reviewed our experience with appendicitis in order to determine the incidence of negative appendectomies and perforation, and the role of delay in diagnosis or treatment. We reviewed 659 appendectomies performed over a 12-month period. Incidental and pediatric appendectomies were excluded. Seventy-five percent of patients were male and 25% female. Nine percent had negative appendectomies and 28% had perforated appendicitis. Perforated appendicitis resulted in increased morbidity and length of stay. Delay in presentation greater than 12 hours after the onset of symptoms significantly increased the perforation rate. In-hospital delay did not affect perforation rate. We have achieved a negative appendectomy rate lower than that in other reported series, while maintaining an acceptable perforation rate. In the majority of patients, perf...

Research paper thumbnail of Secondary prevention and risk factor target achievement in a global, high-risk population with established coronary heart disease: baseline results from the STABILITY study

European journal of preventive cardiology, 2013

There is limited contemporary data on achievement of risk factor goals for secondary prevention o... more There is limited contemporary data on achievement of risk factor goals for secondary prevention of cardiovascular (CV) disease from countries in many regions of the world. This report describes the global and regional prevalence of CV risk factors and use of preventive medications at baseline in participants in the ongoing STabilization of Atherosclerotic plaque By Initiation of darapLadIb TherapY (STABILITY) trial. Detailed individual data on CV risk factors were obtained before randomization in 15,828 patients with chronic coronary heart disease (CHD) from 39 countries on five continents. Subjects had a history of myocardial infarction, prior coronary revascularization, or multi-vessel CHD without revascularization and at least one additional CV risk factor. The majority were taking a statin (97%), antiplatelet therapy (96%), beta-blocker (79%), or angiotensin converting enzyme inhibitor/angiotensin receptor blocker (77%). However, a large proportion of patients did not achieve gu...

Research paper thumbnail of New ST-depression: an under-recognized high-risk category of 'complete' ST-resolution after reperfusion therapy

European heart journal. Acute cardiovascular care, 2012

It is not known if there is an association between resolution of ST-elevation to ST-depression fo... more It is not known if there is an association between resolution of ST-elevation to ST-depression following fibrinolysis and 30-day mortality. In an ECG substudy of HERO-2, which compared bivalirudin to unfractionated heparin following streptokinase in 12,556 patients with ST-elevation myocardial infarction ECGs were recorded at baseline and at 60 minutes after commencing fibrinolysis. The main outcome measure was 30-day mortality. Using summed ST-segment elevation and five categories of changes in the infarct leads, further ST-elevation, 0-30% ST-resolution, >30-70% (partial) ST-resolution, >70% (complete) ST-resolution, and new ST-depression occurred in 21.7, 24.9, 36.8, 14.8, and 1.8% of patients, with 30-day mortality of 12.3, 11.7, 8.0, 4.2, and 8.1%, respectively. For the comparison of new ST-depression with complete ST-resolution and no ST-depression, p<0.01 with 24-hour mortality 4.5 vs. 1.3%, respectively (p=0.0003). Patients with new ST-depression had similar peak ca...

Research paper thumbnail of O047 Comparing Contemporary Coronary Artery Bypass Grafting Across Six Main Ethnic Groups of New Zealand: Another Example of Inequalities In Cardiovascular Disease

Research paper thumbnail of O220 Performance Of Euroscore I, Euroscore Ii And Society Of Thoracic Surgeon’S Risk Models To Predict Adverse Outcomes After Isolated Coronary Artery Bypass Grafting

Research paper thumbnail of PM225 Utility of High-Sensitivity Troponin To Diagnose Myocardial Infarction After Isolated Aortic Valve Replacement

Research paper thumbnail of Complex valve disease: pre-surgical functional capacity evaluation using peak oxygen consumption

The Journal of heart valve disease, 2009

Complex heart valve disease constitutes both mixed and multiple valve pathologies that coexist in... more Complex heart valve disease constitutes both mixed and multiple valve pathologies that coexist in a single heart. The chronicity of complex valve disease results in a slow decline in functional capacity. Currently, very few data exist relating to chronic complex valve disease. The clinical assessment of exertional dyspnea (NYHA class) is central to the decision to operate and predict a prognosis. Dyspnea causes significant functional limitations. Peak oxygen consumption (peak VO2) is the 'gold standard' of objectively measuring functional aerobic capacity, and is an important predictor of prognosis. The onset of dyspnea is the most common indication for valve surgery. The study aim, in patients with complex valve disease, was to: (i) objectively assess functional aerobic capacity using peak VO2; and (ii) compare the differences between NYHA classes I and II in relation to body composition, echocardiographic severity, and functional capacity A total of 45 patients with comple...