Binita Shah

The relationship between diabetes, metabolic syndrome, and platelet activity as measured by mean platelet volume: the National Health And Nutrition Examination Survey, 1999-2004.

OBJECTIVE The association between platelet activity, diabetes, and glucometabolic control is uncertain. We aim to investigate mean platelet volume (MPV), a marker of platelet size and platelet activity, with the prevalence of diabetes, metabolic syndrome, and degree of glycemic control. RESEARCH DESIGN AND METHODS This is a retrospective analysis of 13,021 participants in the National Health and Nutrition Examination Survey from 1999 to 2004. Prevalence of diabetes was defined as nonfasting glucose >200 mg/dL, fasting glucose ≥126 mg/dL, or treatment with hypoglycemic agents. Presence of metabolic syndrome was determined by the National Cholesterol Education Program Adult Treatment Panel III definition. Odds ratios and 95% CIs were estimated by logistic regression. RESULTS MPV was significantly higher in subjects with diabetes (8.20 vs. 8.06 femtoliter [fL], P < 0.01) but not in subjects with metabolic syndrome (8.09 vs. 8.07 fL, P = 0.24). For the metabolic syndrome components, MPV was significantly higher in abdominal obesity (P = 0.03) and low HDL (P = 0.04), and not different in high blood pressure (P = 0.07), abnormal glucose metabolism (P = 0.71), or hypertriglyceridemia (P = 0.46). There was a significant correlation between MPV and glucose (P < 0.0001) and between MPV and hemoglobin A1c (P < 0.0001) in subjects with diabetes. These correlations were no longer significant in those without diabetes. The adjusted odds of diabetes rose with increasing MPV levels and were most pronounced in subjects with MPV levels exceeding the 90th percentile (≥9.31 fL). The association between MPV and diabetes was most apparent in those with the poorest glucose control. CONCLUSIONS Mean platelet volume is strongly and independently associated with the presence and severity of diabetes.

Colchicine: Old and New

Although colchicine has been a focus of research, debate, and controversy for thousands of years, the US Food and Drug Administration just approved it in 2009. Over the past decade, advances in the knowledge of colchicine pharmacology, drug safety, and mechanisms of action have led to changes in colchicine dosing and to potential new uses for this very old drug. In this review, we discuss the pharmacologic properties of colchicine and summarize what is currently known about its mechanisms of action. We then discuss and update the use of colchicine in a variety of illnesses, including rheumatic and, most recently, cardiovascular diseases.

Radiation exposure during coronary angiography via transradial or transfemoral approaches when performed by experienced operators

BACKGROUND Studies demonstrate an increase in radiation exposure with transradial approach (TRA) when compared with transfemoral approach (TFA) for coronary angiography. Given the learning curve associated with TRA, it is not known if this increased radiation exposure to patients is seen when procedures are performed by experienced operators. METHODS We retrospectively evaluated 1,696 patients who underwent coronary angiography with or without percutaneous coronary intervention (PCI) by experienced operators at a tertiary center from October 2010 to June 2011. Experienced operators were defined as those that perform >75 PCIs/year with >95% of cases performed using the TRA or TFA approach for ≥5 years. The outcomes of interest were dose area product (DAP) and fluoroscopy time (FT). RESULTS Of the 1,696 patients, 1,382 (81.5%) were performed by experienced femoral operators using TFA and 314 (18.5%) were performed by experienced radial operators using TRA. Most of these cases (65.4%) were diagnostic only (870 TFA and 240 TRA) with both DAP (6040 [3210-8786] vs 5019 [3377-6869] μGy·m(2), P = .003] and FT [6.2 [4.0-10.3] vs 3.3 [2.6-5.0] minutes, P < .001) significantly higher using TRA versus TFA. For procedures involving PCI, despite similar baseline patient, procedural and lesion characteristics, DAP and FT remained significantly higher using TRA versus TFA (19,649 [11,996-25,929] vs 15,395 [10,078-21,617] μGy·m(2), P = .02 and 22.1 [13.3-31.0] vs. 13.8 [9.8-20.3] minutes, P < .001). CONCLUSIONS In a contemporary cohort of patients undergoing coronary angiography by experienced operators, TRA was associated with higher radiation exposure when compared with TFA.

In-Hospital Switching Between Clopidogrel and Prasugrel Among Patients With Acute Myocardial Infarction Treated With Percutaneous Coronary Intervention Insights Into Contemporary Practice From the National Cardiovascular Data Registry

Background—Although randomized clinical trials have compared clopidogrel with higher potency ADP receptor inhibitors (ADPris) among patients with myocardial infarction, little is known about the frequency and factors associated with switching between ADPris in clinical practice. Methods and Results—We studied 47 040 patients with myocardial infarction treated with percutaneous coronary intervention, who received either clopidogrel or prasugrel within 24 hours of admission at 361 US hospitals from July 2009 to June 2011 using the merged Acute Coronary Treatment and Intervention Outcomes Network Registry–Get With the Guidelines and CathPCI Registry database. Hierarchical logistic regression modeling was used to determine factors independently associated with in-hospital ADPri switching. Among 40 531 patients treated initially in-hospital with clopidogrel, 2125 (5.2%) were discharged on prasugrel; this frequency steadily increased from 0% to 7% during the study period. Among 6509 patients treated initially in-hospital with prasugrel, 751 (11.5%) were discharged on clopidogrel. The frequency of this switch increased from 6% to 18% during the first 2 quarters of the study period and decreased to 9% by the end. Switching clopidogrel to prasugrel was associated with high-risk angiographic characteristics (thrombotic, long, and bifurcating lesions), reinfarction in-hospital, and private health insurance coverage. Older age, previous cerebrovascular event, in-hospital coronary artery bypass grafting, in-hospital bleeding, and warfarin use at discharge were associated with switching prasugrel to clopidogrel. Conclusions—Clopidogrel and prasugrel are not uncommonly switched in-hospital in patients with myocardial infarction undergoing percutaneous coronary intervention. In contemporary US practice, in addition to risk for bleeding and recurrent ischemic events, medical drug coverage is a major determinant of ADPri selection.

Mean platelet volume reproducibility and association with platelet activity and anti-platelet therapy

Abstract Some studies suggest that mean platelet volume (MPV) correlates with increased risk for cardiovascular morbidity and mortality. In this study, we aim to assess reproducibility, need for standardized measurements, effect of aspirin, and association with other established markers of platelet activity. Following an overnight fast, 48 healthy volunteers had weekly assessment of platelet activity and were administered aspirin 81 mg daily for 7 d between weeks 3 and 4. We investigated the influence of time between phlebotomy and MPV measurement (n = 10). Reproducibility was assessed by coefficient of variation (CV) and intraclass correlation coefficient (ICC). MPV measurements were reproducible (Week 1: 10.6 fL [9.9–11], Week 2: 10.6 fL [10.0–10.9], Week 3: 10.6 fL [9.8–11]). CV was ≤4% and ICC > 0.85 (p < 0.001) for each comparison, indicating excellent reproducibility. There was no effect of aspirin on MPV (10.6 fL [9.8–11] versus 10.5 fL [9.9–11]; p = 0.81). MPV significantly increased as time between phlebotomy and MPV measurement increased (Spearman’s rho = 0.94, p = 0.001). Increasing MPV tertiles was associated with collagen- and thrombin receptor-activated peptide-induced platelet aggregation but not with ADP- or arachidonic acid-induced or spontaneous platelet aggregation. In conclusion, when standardized, MPV is a reproducible marker of platelet size and not affected by low-dose aspirin. MPV is modestly associated with some, but not all, markers of platelet activity.

Drug-Eluting Stents: the Past, Present, and Future

Since the advent of percutaneous coronary intervention, enormous advances have been made in the treatment of coronary artery disease. Angioplasty and bare metal stents were plagued by high rates of restenosis leading to repeat revascularization procedures. Examination of the underlying pathophysiology of restenosis led to the development of drug-eluting stents to reduce neointimal hyperplasia. However, as restenosis rates declined, length of dual antiplatelet therapy use and risk of long-term stent thrombosis associated with drug-eluting stents increased. Subsequent generations have improved each facet of stent design. Novel alloys maintain durability and reduce strut thickness to increase deliverability, biocompatible polymers decrease the inflammatory response and improve drug elution kinetics, and new generations of drugs predictably inhibit restenosis. Developments on the horizon include stents with bioabsorbable polymers and platforms. The purpose of this review is to assess the evolution of stent design and the evidence behind each generation and to peer into the future of stent technology.

Diabetes and Vascular Disease in Different Arterial Territories

OBJECTIVE The aim of this study was to investigate the relationship between diabetes and different phenotypes of peripheral vascular disease (lower extremity peripheral artery disease [PAD], carotid artery stenosis [CAS], and abdominal aortic aneurysm [AAA]). RESEARCH DESIGN AND METHODS Prevalence of vascular disease was evaluated in 3,696,778 participants of the Life Line Screening survey between 2003 and 2008. PAD was defined as ankle-brachial pressure index <0.90 or prior revascularization, CAS as ≥50% stenosis or prior revascularization, and AAA as infrarenal aortic diameter ≥3 cm or prior repair. Odds ratios (ORs) and 95% CIs were assessed using logistic regression modeling. RESULTS Diabetes mellitus was present in 10.8% of participants (n = 399,884). Prevalence of PAD, CAS, and AAA was significantly higher (P < 0.0001) in participants with compared with those without diabetes. After multivariate adjustment for baseline demographics and clinical risk factors, a significant interaction existed between diabetes and vascular disease phenotype (P < 0.0001). Diabetes was associated with increased odds of PAD (OR 1.42 [95% CI 1.41–1.4]; P < 0.0001) and CAS (1.45 [1.43–1.47]; P < 0.0001) but decreased odds of AAA (0.86 [0.84–0.88]; P < 0.0001). The strength of association increased with increasing severity of disease in each vascular phenotype, and this association persisted in the population with asymptomatic vascular disease. CONCLUSIONS In a large population-based study, the association between diabetes and vascular disease differed according to vascular phenotype. Future studies exploring the mechanism for these vascular-specific differences are needed.

Provoking conditions, management and outcomes of type 2 myocardial infarction and myocardial necrosis

BACKGROUND Type 2 myocardial infarction (MI) is defined as myocardial necrosis (myonecrosis) due to an imbalance in supply and demand with clinical evidence of ischemia. Some clinical scenarios of supply-demand mismatch predispose to myonecrosis but limit the identification of symptoms and ECG changes referable to ischemia; therefore, the MI definition may not be met. Factors that predispose to type 2 MI and myonecrosis without definite MI, approaches to treatment, and outcomes remain poorly characterized. METHODS Patients admitted to an academic medical center with an ICD-9 diagnosis of secondary myocardial ischemia or non-primary diagnosis of non-ST-elevation MI were retrospectively reviewed. Cases were classified as either MI (n=255) or myonecrosis without definite MI (n=220) based on reported symptoms, ischemic ECG changes, and new wall motion abnormalities. RESULTS Conditions associated with type 2 MI or myonecrosis included non-cardiac surgery (38%), anemia or bleeding requiring transfusion (32%), sepsis (31%), tachyarrhythmia (23%), hypotension (22%), respiratory failure (23%), and severe hypertension (8%). Inpatient mortality was 5%, with no difference between patients with MI and those with myonecrosis (6% vs. 5%, p=0.41). At discharge, only 43% of patients received aspirin and statin therapy. CONCLUSIONS Type 2 MI and myonecrosis occur frequently in the setting of supply-demand mismatch due to non-cardiac surgery, sepsis, or anemia. Myonecrosis without definite MI is associated with similar in-hospital mortality as type 2 MI; both groups warrant further workup for cardiovascular disease. Antiplatelet and statin prescriptions were infrequent at discharge, reflecting physician uncertainty about the role of secondary prevention in these patients.

Hyperglycemia in Nondiabetic Patients Presenting With Acute Myocardial Infarction

Abstract:Hyperglycemia is common in nondiabetic patients with acute myocardial infarction (AMI). Elevated blood glucose level may reflect a response to stress, an underlying abnormal glucometabolic state or both. Regardless of mechanism, hyperglycemia complicating AMI is associated with an inflammatory and prothrombotic state, depressed myocardial contractility and increased short- and long-term mortality. Studies are needed to define optimal monitoring and management of hyperglycemia in nondiabetic patients with AMI.

Revascularization Strategies in Patients with Diabetes Mellitus and Acute Coronary Syndrome

Patients with diabetes mellitus (DM) have more severe CAD and higher mortality in acute coronary syndrome (ACS) than patients without DM. The optimal mode of revascularization—coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI)—remains controversial in this setting. For patients with DM and ST-segment elevation myocardial infarction, prompt revascularization of the culprit artery via PCI is generally preferable. In non-ST-elevation ACS, the decision on mode of revascularization is more challenging. Trials comparing CABG with percutaneous transluminal coronary angioplasty, bare metal stents, and first-generation drug-eluting stents in DM patients with multivessel have demonstrated decreased mortality in those receiving CABG. On the other hand, trials and retrospective analyses comparing CABG to PCI with second-generation drug-eluting stents have not shown a statistically significant mortality benefit favoring CABG. This potentially narrowed that gap between CABG and PCI requires further investigation.