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.

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 micromol/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 micromol/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.

Functional effects of high clopidogrel maintenance dosing in patients with inadequate platelet inhibition on standard dose treatment.

Updated guidelines on percutaneous coronary intervention recommend increasing the dose of clopidogrel to 150 mg in high-risk patients if <50% platelet inhibition is demonstrated. However, to date, the functional impact of this recommendation has been poorly explored. The aim of this study was to assess the functional implications associated with the use of clopidogrel 150 mg/day in patients with inadequate platelet inhibition while receiving standard 75 mg/day maintenance treatment. Patients with diabetes mellitus have a higher prevalence of inadequate clopidogrel-induced antiplatelet effects and stent thrombosis compared with those without diabetes and were selected for this analysis. Platelet inhibition was assessed using the VerifyNow P2Y12 assay in patients with type 2 diabetes receiving dual-antiplatelet therapy. Patients (n = 17) with <50% platelet inhibition were treated with clopidogrel 150 mg/day for 1 month. Adenosine diphosphate-induced aggregation and the P2Y12 reactivity ratio were also assessed. Platelet function profiles were compared with that of a control group (n = 17) with >or=50% inhibition. Platelet inhibition increased from 27.1 +/- 12% to 40.6 +/- 18% in patients treated with clopidogrel 150 mg/day (p = 0.009; primary end point). All other functional measures also showed enhanced clopidogrel-induced antiplatelet effects. The degree of platelet inhibition achieved after treatment with clopidogrel 150 mg/day varied broadly, and only 35% of patients yielded a degree of platelet inhibition >or=50%. Increasing the dose in patients with inadequate response to clopidogrel did not reach the same degree of antiplatelet effects as those achieved in patients with adequate response while receiving 75 mg/day. In conclusion, the use of a 150 mg maintenance dose of clopidogrel in patients with type 2 diabetes with <50% platelet inhibition is associated with enhanced antiplatelet effects. However, the antiplatelet effects achieved are nonuniform, and a considerable number of patients persist with inadequate platelet inhibition.

Left ventricular dysfunction after pericardiectomy for constrictive pericarditis.

A 56-year-old man was admitted to our hospital with a diagnosis of suspected constrictive pericarditis. After the diagnosis was confirmed by cardiac catheterization, an elective pericardiectomy was performed without complication. Four days after surgery dyspnea developed in the patient, and he was found to have an acute decrease in left ventricular ejection fraction (LVEF) by echocardiography. The patient's symptoms and the LVEF improved over time and returned to normal 4 weeks after surgery. Transient hemodynamic dysfunction of the left ventricle has previously been reported after pericardiectomy or pericardiocentesis; however, we know of no reports in the literature that confirm an acute reduction in LVEF by echocardiography after pericardiectomy for constrictive pericarditis.

Impact of P2Y(12) inhibitory effects induced by clopidogrel on platelet procoagulant activity in type 2 diabetes mellitus patients.

INTRODUCTION: Type 2 diabetes mellitus (T2DM) patients have a variable response profile to the P2Y(12) receptor antagonist clopidogrel. P2Y(12) receptor signalling promotes platelet procoagulant activity. The aim of this study was to determine if T2DM patients with suboptimal clopidogrel response have greater platelet procoagulant activity compared with optimal responders and evaluate if this can be modulated by enhancing P2Y(12) receptor inhibition. MATERIALS AND METHODS: A total of 50 T2DM patients in a steady state phase of clopidogrel therapy were studied. Suboptimal responders were randomly assigned to standard (75 mg) or high (150 mg) clopidogrel maintenance therapy for one-month. Afterwards, all patients resumed standard therapy. Platelet procoagulant activity assessed by thrombin-induced platelet-fibrin clot formation using thrombelastography (TEG) was determined at baseline, one-month post-randomization, and one-month after resuming standard therapy. RESULTS: In the overall study population, the reaction time (R), a measure of time to initial thrombin induced platelet-fibrin clot formation, and the time to maximum rate of thrombin generation (TMRTG) values were 6.3+/-1.7 and 7.6+/-1.9 minutes, respectively. Suboptimal clopidogrel responders (n=30) had acceleration of R (p=0.002) and TMRTG (p=0.002) compared to optimal responders (n=20). Suboptimal clopidogrel responders treated with a 150 mg dose showed prolongation of R (p=0.0001) and TMRTG (p<0.0001), which returned to baseline values after resuming standard dosage. No differences were observed among patients randomized to 75 mg. CONCLUSIONS: T2DM patients with suboptimal clopidogrel response have enhanced platelet procoagulant activity compared to patients with optimal response, which can be down-regulated by more potent platelet P2Y(12) inhibition using high clopidogrel maintenance dosing.

Cardiac transplantation in patients with anti-phospholipid antibodies.

Patients with severe heart failure are known to have an increased incidence of thromboembolic events and frequently have a visible thrombus in the left ventricle. Thromboemboli in heart failure patients are usually attributed to the underlying heart failure, and alternative etiologies for thrombus formation are rarely sought. However, anti-phospholipid antibodies and other inherited or acquired clotting abnormalities may contribute to hypercoagulability in heart failure patients and can lead to a persistent high risk for clotting, even after heart transplantation has corrected the underlying heart failure. We report outcomes with heart transplantation in 3 young patients with anti-phospholipid antibodies and a history of pre-heart transplantation thromboembolic events, and demonstrate the importance of post-heart transplantation anti-coagulation in these patients.