Faculty Bibliography

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.

OBJECTIVEThe 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 METHODSPrevalence 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.RESULTSDiabetes mellitus was present in 10.8% of participants (n = 399,884). Prevalence of PAD, CAS, and AAA were 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.CONCLUSIONSIn 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.

Periprocedural hyperglycemia is an independent predictor of mortality in patients who underwent percutaneous coronary intervention (PCI). However, periprocedural management of blood glucose is not standardized. The effects of routinely continuing long-acting glucose-lowering medications before coronary angiography with possible PCI on periprocedural glycemic control have not been investigated. Patients with diabetes mellitus (DM; n = 172) were randomized to continue (Continue group; n = 86) or hold (Hold group; n = 86) their clinically prescribed long-acting glucose-lowering medications before the procedure. The primary end point was glucose level on procedural access. In a subset of patients (no DM group: n = 25; Continue group: n = 25; and Hold group: n = 25), selected measures of platelet activity that change acutely were assessed. Patients with DM randomized to the Continue group had lower blood glucose levels on procedural access compared with those randomized to the Hold group (117 [97 to 151] vs 134 [117 to 172] mg/dl, p = 0.002). There were two hypoglycemic events in the Continue group and none in the Hold group, and no adverse events in either group. Selected markers of platelet activity differed across the no DM, Continue, and Hold groups (leukocyte platelet aggregates: 8.1% [7.2 to 10.4], 8.7% [6.9 to 11.4], 10.9% [8.6 to 14.7], p = 0.007; monocyte platelet aggregates: 14.0% [10.3 to 16.3], 20.8% [16.2 to 27.0], 22.5% [15.2 to 35.4], p <0.001; soluble p-selectin: 51.9 ng/ml [39.7 to 74.0], 59.1 ng/ml [46.8 to 73.2], 72.2 ng/ml [58.4 to 77.4], p = 0.014). In conclusion, routinely continuing clinically prescribed long-acting glucose-lowering medications before coronary angiography with possible PCI help achieve periprocedural euglycemia, appear safe, and should be considered as a strategy for achieving periprocedural glycemic control.

Coronary angiography is the gold standard for defining obstructive coronary disease. However, radiation exposure remains an unwanted hazard. Patients referred for coronary angiography with abdominal circumference <45 inches and glomerular filtration rate >60 ml/min were randomized to the fluorography (n = 25) or cineangiography (n = 25) group. Patients in the fluorography group underwent coronary angiography using retrospectively stored fluorography with repeat injection under cineangiography only when needed for better resolution per operator's discretion. Patients in the cineangiography group underwent coronary angiography using routine cineangiography. The primary end point was patient radiation exposure measured by radiochromic film. Secondary end points included the radiation output measurement of kerma-area product and air kerma at the interventional reference point (Ka,r) and operator radiation exposure measured by a dosimeter. Patient radiation exposure (158.2 mGy [76.5 to 210.2] vs 272.5 mGy [163.3 to 314.0], p = 0.001), kerma-area product (1,323 muGy.m(2) [826 to 1,765] vs 3,451 muGy.m(2) [2,464 to 4,818], p <0.001), and Ka,r (175 mGy [112 to 252] vs 558 mGy [313 to 621], p <0.001) were significantly lower in the fluorography compared with cineangiography group (42%, 62%, and 69% relative reduction, respectively). Operator radiation exposure trended in the same direction, although statistically nonsignificant (fluorography 2.35 muGy [1.24 to 6.30] vs cineangiography 5.03 muGy [2.48 to 7.80], p = 0.059). In conclusion, the use of fluorography in a select group of patients during coronary angiography, with repeat injection under cineangiography only when needed, was efficacious at reducing patient radiation exposure.

BACKGROUND: Recent initiatives have focused on primary prevention to delay time to first myocardial infarction (MI). The aim of this study was to evaluate the change in risk factor profile over time in patients without known cardiovascular disease presenting with first MI. METHODS: In the American Heart Association's Get With The Guidelines-Coronary Artery Disease national registry, 100,884 patients without known cardiovascular disease presenting with acute MI from 408 hospitals were evaluated between 2002 and 2008. The time trends of the proportion of patients with cardiovascular risk factors (nonmodifiable: age >45 years for men or >55 years for women, male sex, modifiable: diabetes mellitus, hypertension, hyperlipidemia, tobacco use) were analyzed. Analyses were stratified by non-ST-segment elevation MI (NSTEMI) versus ST-segment elevation MI (STEMI). RESULTS: The proportion of patients with >/=3 of 6 traditional risk factors slightly decreased over time in the NSTEMI (69.5%-66.8%, P < .0001) and STEMI (68.9%-66.4%, P < .0001) cohorts. The proportion of patients with >/=2 of 4 modifiable risk factors increased from 52% to 59% and then declined to 52.1% (P < .0001) in the NSTEMI cohort but declined slightly in the STEMI cohort (50.9%-47.3%, P < .0001). After adjusting for age and gender, the time trend of proportion with diabetes mellitus, hypertension, and tobacco use declined in both cohorts. However, the proportion of patients with hyperlipidemia remained similar. CONCLUSIONS: Although risk factor profiles in patients presenting with first MI have shown improvements over time, the changes are modest.

Background: Observation of the kinetics of tissue enhancement after the injection of a bolus of tracer has been used for the analysis of perfusion and related variables. In general, a gradient of concentration in the exchanging vascular compartment between the arterial and venous ends is represented in models via focus on maintaining the detailed balance between the advective and diffusive exchange processes. Conventionally, this is by considering the exchange in an Eulerian framework, based on considering the exchange within each compartment as a separate unit (e.g., tissue homogeneity (TH) model [1]). Herein, we present a Lagrangian approach to the exchange modeling, such that the blood flowing between compartments is considered as the primary unit, and, thereby, allowing for coarser discretization and more efficient calculations (Figure 1a). Methods: Eight patients (age 63 + 12 years) underwent first-pass perfusion (FPP) rest and regadenoson stress cardiac MRI (CMR) (3T scanner, Tim Trio, Siemens), followed by invasive coronary angiography. Images were obtained at 4 slice locations (the aortic root for the arterial input function (AIF) and 3 short-axis slices of the left ventricle for the wall) using a TurboFLASH readout with centric k-space reordering [2]. A proton density-weighted image was acquired for normalization [3]. Myocardial blood flow (MBF) (mL/g/min) and perfusion reserve index (MPRI) were calculated in endocardial and epicardial areas (total 32 segments) using our method by an expert in the field of MRI blinded to coronary angiography results. Results: The results of a representative patient (66 year old man) with history of hypertension, hyperlipidemia, Diabetes Mellitus and known coronary artery disease with prior stents on maximal medical therapy are shown in Figure 1b-f. Coronary angiography was performed via the right femoral artery and demonstrated severe triple-vessel disease with left to right collaterals (Figure 1b). First-pass CMR perfusion imaging demonstrates a delay!

Numerous definitions have been proposed for the diagnosis of myocardial infarction (MI) after coronary revascularization. The universal definition for MI designates post procedural biomarker thresholds for defining percutaneous coronary intervention (PCI)-related MI (type 4a) and coronary artery bypass grafting (CABG)-related MI (type 5) which are of uncertain prognostic importance. In addition, for both MI types cTn is recommended as the biomarker of choice, the prognostic significance of which is less well validated than CK-MB. Widespread adoption of a MI definition not clearly linked to subsequent adverse events such as mortality or heart failure may have serious consequences for the appropriate assessment of devices and therapies, may affect clinical care pathways, and may result in misinterpretation of physician competence. Rather than employing an MI definition sensitive for small degrees of myonecrosis (the occurrence of which, based on contemporary large-scale studies, are unlikely to have important clinical consequences), it is instead recommended that a threshold level of biomarker elevation which has been strongly linked to subsequent adverse events in clinical studies be used to define a "clinically relevant MI." The present document introduces a new definition for "clinically relevant MI" after coronary revascularization (PCI or CABG) which is applicable for use in clinical trials, patient care, and quality outcomes assessment. (c) 2013 Wiley Periodicals, Inc.

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 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.