Theodore A. Bass

Randomized Comparison of a High Clopidogrel Maintenance Dose in Patients With Diabetes Mellitus and Coronary Artery Disease Results of the Optimizing Antiplatelet Therapy in Diabetes Mellitus (OPTIMUS) Study

Background— After treatment with clopidogrel, patients with type 2 diabetes mellitus (T2DM) have reduced platelet inhibition compared with patients who are not diabetic. Whether platelet inhibition can be enhanced by increasing clopidogrel maintenance dosage in T2DM patients is unknown. The aim of this pilot study was to assess the functional impact of a high maintenance dose in T2DM patients with suboptimal clopidogrel-induced antiplatelet effects. Methods and Results— T2DM patients on chronic dual antiplatelet therapy were screened to identify suboptimal clopidogrel responders. The latter were randomized to 30-day treatment with a standard (75 mg; n=20) or high (150 mg; n=20) daily maintenance dose. Platelet function was assessed at 3 time points: baseline, 30 days after randomization, and 30 days after resuming standard dosing. Platelet function parameters included adenosine diphosphate–induced (20 and 5 &mgr;mol/L) maximal and late platelet aggregation, inhibition of platelet aggregation, platelet disaggregation, and P2Y12 reactivity index. A total of 64 T2DM patients were screened to identify 40 suboptimal responders. After randomization, maximal adenosine diphosphate–induced (20 &mgr;mol/L) platelet aggregation was significantly reduced in the 150-mg group compared with the 75-mg group (P=0.002; primary end point). However, suboptimal clopidogrel response was still present in 60% of patients on the 150-mg regimen. All other platelet function parameters showed enhanced clopidogrel-induced antiplatelet effects with 150 mg, which returned to baseline values after resumption of standard dosing. Conclusions— A 150-mg maintenance dose of clopidogrel is associated with enhanced antiplatelet effects compared with 75 mg in high-risk T2DM patients. However, enhanced ex vivo platelet reactivity continues to persist, the clinical implications of which are unknown and need to be evaluated in large-scale clinical trials.

Restenosis after coronary angioplasty: A multilvariate statistical model to relate lesion and procedure variables to restenosis☆

The Multi-Hospital Eastern Atlantic Restenosis Trial group obtained follow-up angiography in 510 patients with 598 successfully dilated coronary lesions who were enrolled in a controlled trial of the effects of a single dose of 1 g of methylprednisolone on restenosis after coronary angioplasty. The overall restenosis rate was 39.6%. The strongest univariate relations to the restenosis rate were found for lesion location (saphenous vein graft, 68%; left anterior descending artery, 45%; left circumflex artery and right coronary artery, 32%; p = 0.002); lesion length (≤4.6 mm, 33%; >4.6 mm, 45%; p = 0.001); percent stenosis before angioplasty (≤73%, 25%; >73%, 43%; p = 0.005), percent stenosis after angioplasty (≤21%, 33%; >21%, 46%; p = 0.017) and arterial diameter (<2.9 mm, 44%; ≥ 2.9 mm, 34%; p = 0.036). Two multivariate models to predict restenosis probability were developed with use of stepwise logistic regression. The preprocedural model, which included only variables whose values were known before angioplasty, entered lesion length, vein graft location, left anterior descending artery location, percent stenosis before angioplasty, eccentric lesion and arterial diameter. The postprocedural model, which also included variables whose values were known after angioplasty was performed, was similar to the preangioplasty model except that it also entered postangioplasty percent stenosis and “optimal” balloon sizing but did not enter eccentric lesion. These data indicate that the probability of restenosis after angioplasty is determined predominantly by the characteristics of the lesion being dilated. They are consistent with the known intimal proliferative mechanism of restenosis, offer a means of identifying lesions at unusually high or low risk of restenosis, and of predicting the likelihood that a particular lesion will restenose after angioplasty and provide a rationale for stratification by restenosis probability in the design of future studies of restenosis.

Intramyocardial, Autologous CD34+ Cell Therapy for Refractory Angina

Rationale: A growing number of patients with coronary disease have refractory angina. Preclinical and early-phase clinical data suggest that intramyocardial injection of autologous CD34+ cells can improve myocardial perfusion and function. Objective: Evaluate the safety and bioactivity of intramyocardial injections of autologous CD34+ cells in patients with refractory angina who have exhausted all other treatment options. Methods and Results: In this prospective, double-blind, randomized, phase II study (ClinicalTrials.gov identifier: NCT00300053), 167 patients with refractory angina received 1 of 2 doses (1×105 or 5×105 cells/kg) of mobilized autologous CD34+ cells or an equal volume of diluent (placebo). Treatment was distributed into 10 sites of ischemic, viable myocardium with a NOGA mapping injection catheter. The primary outcome measure was weekly angina frequency 6 months after treatment. Weekly angina frequency was significantly lower in the low-dose group than in placebo-treated patients at both 6 months (6.8±1.1 versus 10.9±1.2, P=0.020) and 12 months (6.3±1.2 versus 11.0±1.2, P=0.035); measurements in the high-dose group were also lower, but not significantly. Similarly, improvement in exercise tolerance was significantly greater in low-dose patients than in placebo-treated patients (6 months: 139±151 versus 69±122 seconds, P=0.014; 12 months: 140±171 versus 58±146 seconds, P=0.017) and greater, but not significantly, in the high-dose group. During cell mobilization and collection, 4.6% of patients had cardiac enzyme elevations consistent with non-ST segment elevation myocardial infarction. Mortality at 12 months was 5.4% in the placebo-treatment group with no deaths among cell-treated patients. Conclusions: Patients with refractory angina who received intramyocardial injections of autologous CD34+ cells (105 cells/kg) experienced significant improvements in angina frequency and exercise tolerance. The cell-mobilization and -collection procedures were associated with cardiac enzyme elevations, which will be addressed in future studies.

A controlled trial of corticosteroids to prevent restenosis after coronary angioplasty. M-HEART Group.

A multicenter, double-blind, placebo-controlled trial was conducted to determine if corticosteroids influence the development of restenosis after successful percutaneous transluminal coronary angioplasty (PTCA). Either placebo or 1.0 g methylprednisolone (steroid) was infused intravenously 2-24 hours before planned PTCA in 915 patients. The PTCA patient success rate was 87% (mean) in the eight centers. There were no differences in clinical or angiographic baseline variables between the two groups. End-point analysis (angiographic restenosis, death, recurrent ischemia necessitating early restudy, and coronary artery bypass graft surgery) showed that there was no significant difference comparing placebo- with steroid-treated patients. Angiographic restudy showed the lesion restenosis rate to be 39% (120 of 307 lesions) after placebo and 40% (117 of 291) after steroid treatment (p = NS). We conclude that pulse steroid pretreatment does not influence the overall restenosis rate after successful PTCA.

Contribution of Gene Sequence Variations of the Hepatic Cytochrome P450 3A4 Enzyme to Variability in Individual Responsiveness to Clopidogrel

Objectives—Metabolic activity of cytochrome P450 (CYP) 3A4 has been associated with clopidogrel response variability. Because metabolic activity of CYP3A4 is genetically regulated, we hypothesized that genetic variations of this enzyme may contribute to clopidogrel response variability. Methods and Results—The CYP3A4*1B, CYP3A4*3, IVS7+258A>G, IVS7+894C>T, and IVS10+12G>A polymorphisms of the CYP3A4 gene were assessed in 82 patients in a steady phase of clopidogrel therapy. Glycoprotein (platelet glycoprotein (GP) IIb/IIIa receptor activation and platelet aggregation were assessed. A cohort of 45 clopidogrel-naïve patients was studied to determine the modulating effects of these polymorphisms after loading dose (300 mg) administration. Only the IVS7+258A>G, IVS7+894C>T, and IVS10+12G>A polymorphisms were sufficiently polymorphic. During the steady phase of clopidogrel treatment, IVS10+12A allele carriers had reduced GP IIb/IIIa activation (P=0.025) and better responsiveness (P=0.02); similarly, clopidogrel-naïve patients carriers of the IVS10+12A allele had reduced GP IIb/IIIa activation during the first 24 hours after a loading dose (P=0.025), increased platelet inhibition (P=0.006), and a more optimal drug response (P=0.003). This polymorphism did not influence platelet aggregation profiles. No association was observed between the other polymorphisms and clopidogrel responsiveness. Conclusions—The IVS10+12G>A polymorphism of the CYP3A4 gene modulates platelet activation in patients treated with clopidogrel and may therefore contribute to clopidogrel response variability.

The Quinapril Ischemic Event Trial (QUIET): evaluation of chronic ace inhibitor therapy in patients with ischemic heart disease and preserved left ventricular function

Angiotensin-converting enzyme inhibitors improve endothelial function, inhibit experimental atherogenesis, and decrease ischemic events. The Quinapril Ischemic Event Trial was designed to test the hypothesis that quinapril 20 mg/day would reduce ischemic events (the occurrence of cardiac death, resuscitated cardiac arrest, nonfatal myocardial infarction, coronary artery bypass grafting, coronary angioplasty, or hospitalization for angina pectoris) and the angiographic progression of coronary artery disease in patients without systolic left ventricular dysfunction. A total of 1,750 patients were randomized to quinapril 20 mg/day or placebo and followed a mean of 27 +/- 0.3 months. The 38% incidence of ischemic events was similar for both groups (RR 1.04; 95% confidence interval 0.89 to 1.22; p = 0.6). There was also no significant difference in the incidence of patients having angiographic progression of coronary disease (p = 0.71). The rate of development of new coronary lesions was also similar in both groups (p = 0.35). However, there was a difference in the incidence of angioplasty for new (previously unintervened) vessels (p = 0.018). Quinapril was well tolerated in patients after angioplasty with normal left ventricular function. Quinapril 20 mg did not significantly affect the overall frequency of clinical outcomes or the progression of coronary atherosclerosis. However, the absence of the demonstrable effect of quinapril may be due to several limitations in study design.

A randomized study assessing the impact of cilostazol on platelet function profiles in patients with diabetes mellitus and coronary artery disease on dual antiplatelet therapy: results of the OPTIMUS-2 study

AIMS Patients with type 2 diabetes mellitus (T2DM) have reduced platelet inhibition compared with non-diabetics following P2Y(12) receptor blockade. Whether inhibition of P2Y(12) signalling can be enhanced by adjunctive treatment with cilostazol in T2DM patients is unknown. The aim of this pilot study was to assess the functional impact of cilostazol in T2DM patients on standard aspirin and clopidogrel treatment. METHODS AND RESULTS This was a prospective, double-blind, double-dummy, placebo-controlled, randomized, cross-over platelet function study. T2DM patients on dual antiplatelet therapy were assigned to receive cilostazol 100 mg or placebo twice daily for 14 days and afterwards crossed-over treatment assignments for another 14 days. Platelet function was performed at three time points: at baseline, 14 days after randomization, and 14 days after treatment cross-over. The P2Y(12) reactivity index, determined through flow cytometric assessment of the phosphorylation status of the vasodilator-stimulated phosphoprotein, was the primary endpoint measure. In addition to this flow cytometric evaluation, light transmittance aggregometry and VerifyNow testing were performed. A total of 25 T2DM patients were randomized; five patients discontinued treatment due to side effects. The P2Y(12) reactivity index was significantly lower following cilostazol treatment compared with placebo (36.3 +/- 20 vs. 59.9 +/- 16%; P = 0.0002). All other P2Y(12)-specific functional assessments showed enhanced inhibition of this signalling pathway following treatment with cilostazol. CONCLUSION Adjunctive treatment with cilostazol in T2DM patients on standard dual antiplatelet therapy enhances inhibition of platelet P2Y(12) signalling.

Impact of Chronic Kidney Disease on Platelet Function Profiles in Diabetes Mellitus Patients With Coronary Artery Disease Taking Dual Antiplatelet Therapy

OBJECTIVES We sought to assess the impact of renal function on platelet reactivity in patients with diabetes mellitus (DM) and coronary artery disease on aspirin and clopidogrel therapy. BACKGROUND Diabetes mellitus is a key risk factor for chronic kidney disease (CKD). In aspirin-treated DM patients the presence of moderate/severe CKD is associated with reduced clinical efficacy of adjunctive clopidogrel therapy. Whether these findings may be attributed to differences in clopidogrel-induced effects is unknown. METHODS This was a cross-sectional observational study in which DM patients taking maintenance aspirin and clopidogrel therapy were studied. Patients were categorized into 2 groups according to the presence or absence of moderate/severe CKD. Platelet aggregation after adenosine diphosphate (ADP) and collagen stimuli were assessed with light transmittance aggregometry and defined patients with high post-treatment platelet reactivity (HPPR). Markers of platelet activation, including glycoprotein IIb/IIIa activation and P-selectin expression, were also determined using flow cytometry. RESULTS A total of 306 DM patients were analyzed. Patients with moderate/severe CKD (n = 84) had significantly higher ADP-induced (60 +/- 13% vs. 52 +/- 15%, p = 0.001) and collagen-induced (49 +/- 20% vs. 41 +/- 20%, p = 0.004) platelet aggregation compared with those without (n = 222). After adjustment for potential confounders, patients with moderate/severe CKD were more likely to have HPPR after ADP (adjusted odds ratio: 3.8, 95% confidence interval: 1.7 to 8.5, p = 0.001) and collagen (adjusted odds ratio: 2.4; 95% confidence interval: 1.1 to 5.4; p = 0.029) stimuli. Markers of platelet activation were significantly increased in patients with HPPR. CONCLUSIONS In DM patients with coronary artery disease taking maintenance aspirin and clopidogrel therapy, impaired renal function is associated with reduced clopidogrel-induced antiplatelet effects and a greater prevalence of HPPR.

Impact of Stent Deployment Procedural Factors on Long-Term Effectiveness and Safety of Sirolimus-Eluting Stents (Final Results of the Multicenter Prospective STLLR Trial)

Drug-eluting stent failures were associated with various clinical factors. However, the clinical impact of stent deployment technique was unknown. This study was designed to evaluate the frequency and impact of suboptimal percutaneous coronary intervention on long-term outcomes of 1,557 patients treated with sirolimus-eluting stents (SESs) in 41 US hospitals. All steps of the interventional procedure were scrutinized by an independent core laboratory to determine the occurrence of geographic miss (GM). GM included longitudinal (LGM; injured or diseased segment not covered by SES) or axial GM (balloon-artery size ratio <0.9 or >1.3) mismatches. Patients with and without GM were stratified (GM vs no-GM group). Patients, investigators, and the independent clinical event adjudication committee were blind to study group assignments. The primary end point was 1-year target-vessel revascularization (TVR) rate. Incidences and predictors of GM and safety outcomes were secondary end points. GM occurred in 943 patients (66.5%): 47.6% had LGM, 35.2% had axial GM, and 16.5% had both. One-year TVR rates were 5.1% in the GM group versus 2.5% in the no-GM group (p=0.025). TVR was 6.1% in the LGM versus 2.6% in the no-LGM subgroups (p=0.001). The association of GM with 1-year TVR was independent of clinical or anatomic factors (hazard ratio 2.0, 95% confidence interval 1.0 to 4.02, p=0.05). There was a 3-fold increase in myocardial infarction rates associated with GM (2.4% vs 0.8%; p=0.04). In conclusion, GM occurred frequently during SES implantation and was associated with increased risk of TVR and myocardial infarction at 1 year. These results emphasized the need for improvement in contemporary percutaneous coronary intervention practices and technologies.

Percutaneous coronary intervention versus coronary artery bypass graft surgery in left main coronary artery disease: a meta-analysis of randomized clinical data

OBJECTIVES The purpose of this study was to determine the safety and efficacy of percutaneous coronary intervention (PCI) compared with coronary artery bypass graft (CABG) in patients with left main coronary artery (LMCA) disease. BACKGROUND Previous meta-analyses of PCI versus CABG in LMCA disease mainly included nonprospective, observational studies. Several new randomized trials have recently been reported. METHODS We identified 1,611 patients from 4 randomized clinical trials for the present meta-analysis. The primary endpoint was the 1-year incidence of major adverse cardiac and cerebrovascular events (MACCE), defined as death, myocardial infarction (MI), target vessel revascularization (TVR), or stroke. RESULTS PCI was associated with a nonsignificantly higher 1-year rate of MACCE compared with CABG (14.5% vs. 11.8%; odds ratio [OR]: 1.28; 95% confidence interval [CI]: 0.95 to 1.72; p = 0.11), driven by increased TVR (11.4% vs. 5.4%; OR: 2.25; 95% CI: 1.54 to 3.29; p < 0.001). Conversely, stroke occurred less frequently with PCI (0.1% vs. 1.7%; OR: 0.15; 95% CI: 0.03 to 0.67; p = 0.013). There were no significant differences in death (3.0% vs. 4.1%; OR: 0.74; 95% CI: 0.43 to 1.29; p = 0.29) or MI (2.8% vs. 2.9%; OR: 0.98; 95% CI: 0.54 to 1.78; p = 0.95). CONCLUSIONS In patients with LMCA disease, PCI was associated with nonsignificantly different 1-year rates of MACCE, death, and MI, a lower risk of stroke, and a higher risk of TVR compared with CABG.