Switching antiplatelet regimens: alternatives to clopidogrel in patients with acute coronary syndrome undergoing PCI: a review of the literature and practical considerations for the interventional cardiologist.

Dual antiplatelet therapy with aspirin plus a P2Y(12) receptor inhibitor is the cornerstone of treatment for patients with acute coronary syndrome and in those undergoing percutaneous coronary intervention. Clopidogrel is the most widely used P2Y(12) receptor inhibitor. Despite the clinical benefits associated with adjunctive clopidogrel therapy, a considerable number of patients continue to experience recurrent cardiovascular events. Importantly, the interindividual response to clopidogrel is variable and is affected by multiple factors, including genetic polymorphisms and drugs that interfere with the conversion of clopidogrel to its active metabolite. The individual variability to clopidogrel-induced antiplatelet effects has significant clinical implications that can result in an increased risk of atherothrombotic recurrences, including stent thrombosis. The introduction of novel P2Y(12) receptor inhibitors, such as prasugrel or ticagrelor, characterized by more potent and consistent platelet inhibitory effects, represents an opportunity for clinicians to consider these alternative therapies to overcome the limitations of clopidogrel. Understanding the strategies and implications of switching antiplatelet treatment regimens is, therefore, key in the clinical setting. This article provides an overview of the literature on switching antiplatelet treatment strategies and practical considerations for the interventional cardiologist.

Impaired aortic distensibility measured by computed tomography is associated with the severity of coronary artery disease.

Impaired aortic distensibility index (ADI) is associated with cardiovascular risk factors. This study evaluates the relation of ADI measured by computed tomographic angiography (CTA) with the severity of coronary atherosclerosis in subjects with suspected coronary artery disease (CAD). Two hundred and twenty-nine subjects,age 63 ± 9 years, 42% female, underwent coronary artery calcium (CAC) scanning and CTA, and their ADI and Framingham risk score (FRS) were measured. End-systolic and end-diastolic (ED) cross-sectional-area(CSA) of ascending-aorta (AAo) was measured 15-mm above the left-main coronary ostium. ADI was defined as: [(Δlumen-CSA)/(lumen-CSA in ED × systemic-pulse-pressure) × 10(3)]. ADI measured by 2D-trans-thoracic echocardiography (TTE) was compared with CTA-measured ADI in 26 subjects without CAC. CAC was defined as 0, 1-100, 101-400 and 400+. CAD was defined as luminal stenosis 0, 1-49% and 50%+. There was an excellent correlation between CTA- and TTE-measured ADI (r(2)=0.94, P=0.0001). ADI decreased from CAC 0 to CAC 400+; similarly from FRS 1-9% to FRS 20% + (P<0.05). After adjustment for risk factors, the relative risk for each standard deviation decrease in ADI was 1.66 for CAC 1-100, 2.26 for CAC 101-400 and 2.32 for CAC 400+ as compared to CAC 0; similarly, 2.36 for non-obstructive CAD and 2.67 for obstructive CAD as compared to normal coronaries. The area under the ROC-curve to predict significant CAD was 0.68 for FRS, 0.75 for ADI, 0.81 for CAC and 0.86 for the combination (P<0.05). Impaired aortic distensibility strongly correlates with the severity of coronary atherosclerosis. Addition of ADI to CAC and traditional risk factors provides incremental value to predict at-risk individuals.

Coronary distensibility index measured by computed tomography is associated with the severity of coronary artery disease.

BACKGROUND: Atherosclerotic changes within the coronary artery wall can affect vessel distensibility. OBJECTIVE: This study evaluated the relationship between the coronary distensibility index (CDI) and the severity of coronary artery disease (CAD) measured by computed tomographic angiography (CTA). METHODS: One hundred thirteen subjects, age 63 +/- 10 years, 32% women, who underwent coronary artery calcium (CAC) scanning and CTA, were studied. Early diastolic and mid diastolic (MD) cross-section area (CSA) of the left anterior descending (LAD) artery were measured 5 mm distal to the left main bifurcation. CDI was defined as Deltalumen CSA/[lumen CSA in MD x estimated central pulse pressure (eCPP)] x 10(3) {eCPP = 0.77 x peripheral pulse pressure}. LAD diameter measured by CTA and quantitative coronary angiography (QCA) was compared in 19 subjects without CAD. CAD was defined as normal (no stenosis and CAC 0), mild (stenosis or= 70%) on CTA. RESULTS: Excellent correlation was observed between CTA and QCA measured by CDI (r(2) = 0.96, P = 0.0001). CDI decreased from normal coronaries (6.75 +/- 1.43) to arteries with mild (5.78 +/- 1.45), moderate (3.96 +/- 1.06), and severe (3.31 +/- 1.06) disease (P = 0.004). The risk factor adjusted odds ratio of lowest versus 2 upper tertiles of CDI was 1.28 for mild, 8.47 for moderate, and 10.59 for severe CAD compared with the normal cohort. The area under the ROC curve to predict obstructive CAD (stenosis >or= 50%) increased significantly from 0.71 to 0.84 by addition of CDI to CAC (P < 0.05). CONCLUSION: CTA-measured CDI is inversely related to the severity of CAD independent of age, sex, cardiovascular risk factors, and CAC.

Effect of preprocedural statin use on procedural myocardial infarction and major cardiac adverse events in percutaneous coronary intervention: a meta-analysis.

BACKGROUND: Multiple primary and secondary prevention trials demonstrate significant reduction in adverse cardiovascular outcomes in patients with, or at risk of, coronary artery disease as a result of statin therapy. This study was conducted to determine whether statin use prior to elective percutaneous coronary intervention (PCI) is associated with lower procedural myocardial infarction (MI) and major adverse cardiovascular events (MACE) in the form of a meta-analysis. METHODS: Trials were eligible for inclusion if they included patients who received a statin prior to PCI and if appropriate documentation of procedural MI was performed. Studies that included acute coronary syndrome patients were excluded. For each trial, the results immediately post intervention and at the longest follow up (up to 12 months) were extracted and analyzed based on an intention-to-treat principle. Six trials involving 2,996 subjects met the inclusion criteria for periprocedural MI and were included in the analysis. Three trials involving 6,723 subjects had appropriate follow up and were analyzed for MACE (the combined endpoint of death, nonfatal MI or target vessel revascularization) up to 12 months after PCI. RESULTS: When the 6 trials included in the main analysis were combined, the summary effect of statins on reducing procedural MI was -5.44% (95% CI -8.2% to -2.7% [p < 0.0001]). There was no evidence of heterogeneity between trials (p = 0.66). The relative risk reduction was 59.3% (9.17% vs. 3.73%; p < 0.001). Sensitivity analysis did not alter this finding. The MACE rates were 19.5% and 15.5% in the control and statin groups, respectively. The overall MACE risk difference was -4.0%, (95% CI -11.4% to +3.4% [p = 0.2900]). The corresponding overall relative risk reduction was 20.5%.