Faculty Bibliography

The Trial to Assess Chelation Therapy 2 (TACT2) is an NIH-sponsored, randomized, 2x2 factorial, double masked, placebo-controlled, multicenter clinical trial testing 40 weekly infusions of a multi-component edetate disodium (disodium ethylenediamine tetra-acetic acid, or Na₂EDTA)-based chelation solution and twice daily oral, high-dose multivitamin and mineral supplements in patients with diabetes and a prior myocardial infarction (MI). TACT2 completed enrollment of 1000 subjects in December 2020, and infusions in December 2021. Subjects are being followed for 2.5 to 5 years. The primary endpoint is a composite of the time to first occurrence of all-cause mortality, MI, stroke, coronary revascularization, or hospitalization for unstable angina. The trial is designed to have >85% power to detect a 30% relative reduction in the primary endpoint for each active treatment versus placebo comparison. TACT2 also includes a Trace Metals and Biorepository Core Lab, which will test the novel hypothesis that the prognostic benefits of chelation, if present, are due to removal of lead and cadmium from patients. Most of the design features of TACT2 were chosen to replicate selected features of the first TACT trial, which demonstrated a statistically significant reduction in cardiovascular outcomes in the EDTA chelation arm compared with placebo among patients with a prior MI, with the largest effect in patients with diabetes. Results from TACT2, if concordant with TACT, will provide definitive evidence of the benefit of edetate disodium-based chelation on cardiovascular outcomes, as well as the possible clinical importance of longitudinal changes in toxic metal levels of participants.

INTRODUCTION/BACKGROUND:The impact of diabetes mellitus (DM) on outcomes of lower extremity revascularization (LER) for peripheral artery disease (PAD) is uncertain. We characterized associations between DM and post-procedural outcomes in PAD patients undergoing LER. METHODS:Adults undergoing surgical or endovascular LER were identified from the 2014 Nationwide Readmissions Database. DM was defined by ICD-9 diagnosis codes and sub-classified based on the presence or absence of complications (poor glycemic control or end-organ damage). Major adverse cardiovascular and limb events (MACLE) were defined as the composite of death, myocardial infarction, ischaemic stroke, or major limb amputation during the index hospitalization for LER. For survivors, all-cause 6-month hospital readmission was determined. RESULTS:Among 39,441 patients with PAD hospitalized for LER, 50.8% had DM. The composite of MACLE after LER was not different in patients with and without DM after covariate adjustment, but patients with DM were more likely to require major limb amputation (5.5% vs. 3.2%, p < 0.001; adjusted odds ratio [aOR] 1.22, 95% CI 1.03-1.44) and hospital readmission (59.2% vs. 41.3%, p < 0.001; aOR 1.44, 95% CI 1.34-1.55). Of 20,039 patients with DM hospitalized for LER, 55.7% had DM with complications. These patients were more likely to have MACLE after LER (11.1% vs. 5.2%, p < 0.001; aOR 1.56 95% CI 1.28-1.89) and require hospital readmission (61.1% vs. 47.2%, p < 0.001; aOR 1.41 95% CI 1.27-1.57) than patients with uncomplicated DM. CONCLUSIONS:DM is present in ≈50% of patients undergoing LER for PAD and is an independent risk factor for major limb amputation and 6-month hospital readmission.

Myocardial injury after non-cardiac surgery (MINS) is common. We investigated the incidence and outcomes of MINS, and mechanistic underpinnings using pre-operative whole blood gene expression profiling in a prospective cohort study of individuals undergoing lower extremity revascularization (LER) for peripheral artery disease (PAD). Major adverse cardiovascular and limb events (MACLE) were defined as a composite of death, myocardial infarction, stroke, major lower extremity amputation or reoperation. Among 226 participants undergoing LER, MINS occurred in 53 (23.5%). Patients with MINS had a greater incidence of major adverse cardiovascular events (49.1% vs. 22.0%, adjusted HR 1.87, 95% CI 1.07-3.26) and MACLE (67.9% vs. 44.5%; adjusted HR 1.66, 95% CI 1.08-2.55) at median 20-month follow-up. Pre-operative whole blood transcriptome profiling of a nested matched MINS case-control cohort (n = 41) identified upregulation of pathways related to platelet alpha granules and coagulation in patients who subsequently developed MINS. Thrombospondin 1 (THBS1) mRNA expression was 60% higher at baseline in patients who later developed MINS, and was independently associated with long-term cardiovascular events in the Duke Catheterization Genetics biorepository cohort. In conclusion, pre-operative THBS1 mRNA expression is higher in patients who subsequently develop MINS and is associated with incident cardiovascular events. Pathways related to platelet activity and coagulation associated with MINS provide novel insights into mechanisms of myocardial injury.

INTRODUCTION/BACKGROUND:Perfluoroalkyl substances (PFAs) are ubiquitous, anthropogenic organic compounds that have been linked with cardiovascular disease and cardiovascular risk factors. Older, long-chain PFAs have been phased out due to adverse cardiometabolic health effect and replaced by newer short-chain PFAs. However, emerging research suggests that short-chain PFAs may also have adverse cardiovascular effects. Non-invasive measures of vascular function can detect preclinical cardiovascular disease and serve as a useful surrogate for early CVD risk. We hypothesized that serum concentrations of PFAs would be associated with noninvasive measures of vascular function, carotid-femoral pulse wave velocity (PWV) and brachial artery reactivity testing (BART), in adults with non-occupational exposure to PFAs. METHODS:We measured serum concentrations of 14 PFAs with hybrid solid-phase extraction and ultrahigh-performance liquid chromatography-tandem mass spectrometry in 94 adult outpatients with no known cardiovascular disease. We collected clinical and demographic data; and measured vascular function, PWV and BART, using standard protocols. We assessed associations of individual PFAs with log-transformed BART and PWV using linear regression. We used weighted quantile sum regression to assess effects of correlated PFA mixtures on BART and PWV. RESULTS:Ten PFAs were measured above the limit of detection in >50% of participants. Each standard deviation increase in concentration of perfluoroheptanoic acid (PFHpA) was associated with 15% decrease in BART (95% CI: -28.5, -0.17). The weighted index of a mixture of PFAs with correlated concentrations was inversely associated with BART: each tertile increase in the weighted PFA mixture was associated with 25% lower BART, with 73% of the effect driven by PFHpA. In contrast, no PFAs or mixtures were associated with PWV. CONCLUSIONS:Serum concentration of PFHpA, a new, short-chain PFA, was associated with impaired vascular function among outpatients without CVD. Our findings support a potential adverse cardiovascular effect of newer, short-chain PFAs.

BACKGROUND:Detection of ≥50% diameter stenosis left main coronary artery disease (LMD) has prognostic and therapeutic implications. Noninvasive stress imaging or an exercise tolerance test (ETT) are the most common methods to detect obstructive coronary artery disease, though stress test markers of LMD remain ill-defined. OBJECTIVES:The authors sought to identify markers of LMD as detected on coronary computed tomography angiography (CTA), using clinical and stress testing parameters. METHODS:This was a post hoc analysis of ISCHEMIA (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches), including randomized and nonrandomized participants who had locally determined moderate or severe ischemia on nonimaging ETT, stress nuclear myocardial perfusion imaging, or stress echocardiography followed by CTA to exclude LMD. Stress tests were read by core laboratories. Prior coronary artery bypass grafting was an exclusion. In a stepped multivariate model, the authors identified predictors of LMD, first without and then with stress testing parameters. RESULTS:Among 5,146 participants (mean age 63 years, 74% male), 414 (8%) had LMD. Predictors of LMD were older age (P < 0.001), male sex (P < 0.01), absence of prior myocardial infarction (P < 0.009), transient ischemic dilation of the left ventricle on stress echocardiography (P = 0.05), magnitude of ST-segment depression on ETT (P = 0.004), and peak metabolic equivalents achieved on ETT (P = 0.001). The models were weakly predictive of LMD (C-index 0.643 and 0.684). CONCLUSIONS:In patients with moderate or severe ischemia, clinical and stress testing parameters were weakly predictive of LMD on CTA. For most patients with moderate or severe ischemia, anatomical imaging is needed to rule out LMD. (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches [ISCHEMIA]; NCT01471522).

BACKGROUND:The ISCHEMIA trial demonstrated no overall difference in the composite primary endpoint and the secondary endpoints of cardiovascular (CV) death/myocardial infarction or all-cause mortality between an initial invasive or conservative strategy among participants with chronic coronary disease and moderate or severe myocardial ischemia. Detailed cause-specific death analyses have not been reported. METHODS:We compared overall and cause-specific death rates by treatment group using Cox models with adjustment for pre-specified baseline covariates. Cause of death was adjudicated by an independent Clinical Events Committee as cardiovascular (CV), non-CV, and undetermined. We evaluated the association of risk factors and treatment strategy with cause of death. RESULTS:Four-year cumulative incidence rates for CV death were similar between invasive and conservative strategies [2.6% vs. 3.0%; hazard ratio (HR) 0.98; 95% CI (0.70 - 1.38)], but non-CV death rates were higher in the invasive strategy [3.3% vs. 2.1%; HR 1.45 (1.00 - 2.09)]. Overall, 13% of deaths were attributed to undetermined causes (38/289). Fewer undetermined deaths [0.6% vs. 1.3%; HR 0.48 (0.24 - 0.95)] and more malignancy deaths [2.0% vs. 0.8%; HR 2.11 (1.23 - 3.60)] occurred in the invasive strategy than in the conservative strategy. CONCLUSIONS:In ISCHEMIA, all-cause and CV death rates were similar between treatment strategies. The observation of fewer undetermined deaths and more malignancy deaths in the invasive strategy remains unexplained. These findings should be interpreted with caution in the context of prior studies and the overall trial results.

AIMS/OBJECTIVE:The International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA) trial prespecified an analysis to determine whether accounting for recurrent cardiovascular events in addition to first events modified understanding of the treatment effects. METHODS AND RESULTS/RESULTS:Patients with stable coronary artery disease (CAD) and moderate or severe ischaemia on stress testing were randomized to either initial invasive (INV) or initial conservative (CON) management. The primary outcome was a composite of cardiovascular death, myocardial infarction (MI), and hospitalization for unstable angina, heart failure, or cardiac arrest. The Ghosh-Lin method was used to estimate mean cumulative incidence of total events with death as a competing risk. The 5179 ISCHEMIA patients experienced 670 index events (318 INV, 352 CON) and 203 recurrent events (102 INV, 101 CON). A single primary event was observed in 9.8% of INV and 10.8% of CON patients while ≥2 primary events were observed in 2.5% and 2.8%, respectively. Patients with recurrent events were older; had more frequent hypertension, diabetes, prior MI, or cerebrovascular disease; and had more multivessel CAD. The average number of primary endpoint events per 100 patients over 4 years was 18.2 in INV [95% confidence interval (CI) 15.8-20.9] and 19.7 in CON (95% CI 17.5-22.2), difference -1.5 (95% CI -5.0 to 2.0, P = 0.398). Comparable results were obtained when all-cause death was substituted for cardiovascular death and when stroke was added as an event. CONCLUSIONS:In stable CAD patients with moderate or severe myocardial ischaemia enrolled in ISCHEMIA, an initial INV treatment strategy did not prevent either net recurrent events or net total events more effectively than an initial CON strategy. CLINICAL TRIAL REGISTRATION/BACKGROUND:ISCHEMIA ClinicalTrials.gov number, NCT01471522, https://clinicaltrials.gov/ct2/show/NCT01471522.

The International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA) found that there was no statistical difference in cardiovascular events with an initial invasive strategy as compared with an initial conservative strategy of guideline-directed medical therapy for patients with moderate to severe ischemia on noninvasive testing. In this study, we describe the reasons that potentially eligible patients who were screened for participation in the ISCHEMIA trial did not advance to enrollment, the step prior to randomization. Of those who preliminarily met clinical inclusion criteria on screening logs submitted during the enrollment period, over half did not participate due to physician or patient refusal, a potentially modifiable barrier. This analysis highlights the importance of physician equipoise when advising patients about participation in randomized controlled trials.

BACKGROUND:Among patients with diabetes and chronic coronary disease, it is unclear if invasive management improves outcomes when added to medical therapy. METHODS:The ISCHEMIA (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches) trials (ie, ISCHEMIA and ISCHEMIA-Chronic Kidney Disease) randomized chronic coronary disease patients to an invasive (medical therapy + angiography and revascularization if feasible) or a conservative approach (medical therapy alone with revascularization if medical therapy failed). Cohorts were combined after no trial-specific effects were observed. Diabetes was defined by history, hemoglobin A1c ≥6.5%, or use of glucose-lowering medication. The primary outcome was all-cause death or myocardial infarction (MI). Heterogeneity of effect of invasive management on death or MI was evaluated using a Bayesian approach to protect against random high or low estimates of treatment effect for patients with versus without diabetes and for diabetes subgroups of clinical (female sex and insulin use) and anatomic features (coronary artery disease severity or left ventricular function). RESULTS:<0.001). At median 3.1-year follow-up the adjusted event-free survival was 0.54 (95% bootstrapped CI, 0.48-0.60) and 0.66 (95% bootstrapped CI, 0.61-0.71) for patients with diabetes versus without diabetes, respectively, with a 12% (95% bootstrapped CI, 4%-20%) absolute decrease in event-free survival among participants with diabetes. Female and male patients with insulin-treated diabetes had an adjusted event-free survival of 0.52 (95% bootstrapped CI, 0.42-0.56) and 0.49 (95% bootstrapped CI, 0.42-0.56), respectively. There was no difference in death or MI between strategies for patients with diabetes versus without diabetes, or for clinical (female sex or insulin use) or anatomic features (coronary artery disease severity or left ventricular function) of patients with diabetes. CONCLUSIONS:Despite higher risk for death or MI, chronic coronary disease patients with diabetes did not derive incremental benefit from routine invasive management compared with initial medical therapy alone. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01471522.