Faculty Bibliography

Objectives: Prevalence of diabetes in peripheral artery disease patients is high and these patients are at increased risk for major cardiovascular events. This study's aim was to use a retrospective cohort to assess healthcare resource use (HRU) and costs among critical limb ischemia (CLI) patients with diabetes. Methods: Using a major US database comprised of integrated administrative claims and electronic health records (2007-15), we estimated annual all-cause HRU and total healthcare costs for a sample of 3,189 CLI adults >= 50 years. CLI was characterized by rest pain, ulceration or gangrene. HRU and costs were calculated from medical and pharmacy claims for 1 year following first diagnosis of CLI (index date). Patients who died in the post-index period were included. We stratified patients into 2 cohorts: with and without pre-index diabetes diagnosis. Reverse Engineering and Forward Simulation (REFSTM), a hypothesis free machine learning platform that uses Bayesian network inference, was used to build an ensemble of prediction models for hospitalization and annual total healthcare costs of CLI patients. Results: Nearly 50% of CLI patients had comorbid diabetes. Diabetics had more hospitalizations (mean [SD]: 1.5 [2.0] vs 1.1 [1.6], p< 0.001) and higher costs ($70,808 [$102,568] vs $43,319 [$76,751], p< 0.001) compared to non-diabetics. REFSTM selected factors with the highest frequency in both models. Those predictive of hospitalization were (OR, SD): cellulitis and abscess (2.1, 0.04), beta blockers non-selective (2.1, 1.3), and other aftercare (1.6, 0.1). Predictors of increased costs were (% change in cost, SD): south region (1.2, 0.03), chronic skin ulcers (2.0, 0.1), and chronic kidney disease (1.9, 0.2). Conclusions: HRU and costs were higher for CLI patients with comorbid diabetes. Factors driving these increases in the overall CLI population may be related to the increased complexity of comorbid diabetes and may provide an opportunity for cost savings via timely care decisions in diabetes and CLI

Aims: Acute myocardial infarction (AMI) is a significant cardiovascular complication following non-cardiac surgery. We sought to evaluate national trends in perioperative AMI, its management, and outcomes. Methods and results: Patients who underwent non-cardiac surgery from 2005 to 2013 were identified using the United States National Inpatient Sample. Perioperative AMI was evaluated over time. Propensity score matching was used to compile a cohort of AMI patients managed invasively (defined as cardiac catheterization or coronary revascularization) vs. conservatively. The primary outcome was in-hospital all-cause mortality. Among 9 566 277 hospitalizations for major non-cardiac surgery, perioperative AMI occurred in 84 093 (0.88%). Over time, the rate of perioperative AMI per 100 000 surgeries declined by 170 [95% confidence intervals (95% CI) 158-181], from 898 in 2005 to 729 in 2013 (P for trend <0.0001). Perioperative AMI occurred most frequently in patients undergoing vascular (2.0%), transplant (1.6%), and thoracic (1.5%) surgery. In-hospital mortality was higher in patients with perioperative AMI than those without AMI [18.0% vs. 1.5%, P < 0.0001; adjusted odds ratio (OR) 5.76, 95% CI 5.65-5.88]. Mortality associated with perioperative AMI declined over time (adjusted OR 0.86, 95% CI 0.84-0.88). In a propensity-matched cohort of 34 650 patients with perioperative AMI, invasive management was associated with lower mortality than conservative management (8.9% vs. 18.1%, P < 0.001; OR 0.44, 95% CI 0.41-0.47). Conclusion: In an observational cohort study from the USA, perioperative AMI occurs in 0.9% of patients undergoing major non-cardiac surgery and is strongly associated with in-hospital mortality. Invasive management of such patients may mitigate some of this excess risk, and further research on the management of perioperative AMI is warranted.

BACKGROUND: Lipoprotein(a) [Lp(a)] is an inherited atherogenic lipoprotein and an independent risk factor for atherosclerotic cardiovascular disease; however, its clinical role remains limited. OBJECTIVE: We hypothesized that Lp(a) screening in high cardiovascular risk patients could provide insight into disease pathogenesis and modify physician behavior for treatment intensification targeting traditional risk factors when Lp(a)-related risk was identified. METHODS: We screened 113 patients presenting electively for percutaneous coronary intervention (PCI) for Lp(a) who met any of the following criteria: (1) premature coronary artery disease (male age <55 years, female age <65 years); (2) family history of premature coronary artery disease; (3) progression to PCI despite well-controlled traditional risk factors (blood pressure <140/90 mm Hg, and low-density lipoprotein cholesterol <100 mg/dL, and HbA1c <7%, and nonsmoker); or (4) progression to PCI despite at least moderate intensity statin use (simvastatin 40, atorvastatin 40-80, or rosuvastatin 20-40 mg daily). RESULTS: In this high-risk cohort, Lp(a) was elevated in nearly half of all subjects, including those with seemingly well-controlled lipids by prior guidelines, suggesting a role for Lp(a) in conferring residual cardiovascular risk. In our cohort, when screened positive, knowledge of an elevated Lp(a) did not influence referring physicians' treatment intensification targeting traditional modifiable cardiovascular risk factors (P = .18). CONCLUSION: When screened judiciously, elevated levels of Lp(a) are highly prevalent in high cardiovascular risk patients, including at a young age, presenting for PCI and may contribute to previously unappreciated residual cardiovascular risk.

Type 2 diabetes mellitus (T2D) is a major risk factor for cardiovascular disease (CVD), the most common cause of death in T2D. Yet, <50% of U.S. adults with T2D meet recommended guidelines for CVD prevention. The burden of T2D is increasing: by 2050, approximately 1 in 3 U.S. individuals may have T2D, and patients with T2D will comprise an increasingly large proportion of the CVD population. The authors believe it is imperative that we expand the use of therapies proven to reduce CVD risk in patients with T2D. The authors summarize evidence and guidelines for lifestyle (exercise, nutrition, and weight management) and CVD risk factor (blood pressure, cholesterol and blood lipids, glycemic control, and the use of aspirin) management for the prevention of CVD among patients with T2D. The authors believe appropriate lifestyle and CVD risk factor management has the potential to significantly reduce the burden of CVD among patients with T2D.

BACKGROUND: The Universal Definition of Myocardial Infarction recommends the 99th percentile concentration of cardiac troponin in a normal reference population as part of the decision threshold to diagnose type 1 spontaneous myocardial infarction. Adoption of this recommendation in contemporary worldwide practice is not well known. METHODS: We performed a cohort study of 276 hospital laboratories in 31 countries participating in the National Heart, Lung, and Blood Institute-sponsored International Study of Comparative Health Effectiveness with Medical and Invasive Approaches trial. Each hospital laboratory's troponin assay manufacturer and model, the recommended assay's 99th percentile upper reference limit (URL) from the manufacturer's package insert, and the troponin concentration used locally as the decision level to diagnose myocardial infarction were ascertained. RESULTS: Twenty-one unique troponin assays from 9 manufacturers were used by the surveyed hospital laboratories. The ratio of the troponin concentration used locally to diagnose myocardial infarction to the assay manufacturer-determined 99th percentile URL was <1 at 19 (6.6%) laboratories, equal to 1 at 91 (31.6%) laboratories, >1 to 5 to 10 at 43 (14.9%) laboratories. The variability in troponin decision level for myocardial infarction relative to the assay 99th percentile URL was present for laboratories in and outside of the United States, as well as for high- and standard-sensitivity assays. CONCLUSIONS: There is substantial hospital-level variation in the troponin threshold used to diagnose myocardial infarction; only one-third of hospital laboratories currently follow the Universal Definition of Myocardial Infarction consensus recommendation for use of troponin concentration at the 99th percentile of a normal reference population as the decision level to diagnose myocardial infarction. This variability across laboratories has important implications for both the diagnosis of myocardial infarction in clinical practice as well as adjudication of myocardial infarction in clinical trials.