Clopidogrel Monotherapy vs. Aspirin Monotherapy Following Short-Term Dual Antiplatelet Therapy in Patients Receiving Everolimus-Eluting Coronary Stent Implantation

Cost-Effectiveness of Clopidogrel vs Aspirin Monotherapy After Percutaneous Coronary Intervention: Results From the HOST-EXAM Study

Background

The HOST-EXAM (Harmonizing Optimal Strategy for Treatment of Coronary Artery Disease-Extended Antiplatelet Monotherapy) trial showed superior efficacy and safety of clopidogrel monotherapy compared with aspirin monotherapy during the chronic maintenance period after percutaneous coronary intervention (PCI).

Objectives

The goal of this study was to investigate the cost-effectiveness of clopidogrel monotherapy compared with that of aspirin monotherapy.

Methods

A Markov model was developed for patients in the stable phase after PCI. From the perspectives of the South Korean, UK, and U.S. health care systems, the lifetime health care costs and quality-adjusted life-years (QALYs) of each strategy were estimated. Transition probabilities were obtained from the HOST-EXAM trial, and health care costs and health-related utilities were obtained from data and literature for each country.

Results

From the perspective of the South Korean health care system, the base-case analysis showed that clopidogrel monotherapy was $3,192 higher in lifetime health care costs and 0.139 lower in QALYs compared with aspirin. This result was greatly influenced by the numerically but insignificantly higher cardiovascular mortality of clopidogrel compared with aspirin. In the analogous UK and U.S. models, clopidogrel monotherapy was projected to decrease health care costs by £1,122 and $8,920 per patient compared with aspirin monotherapy while reducing QALYs by 0.103 and 0.175, respectively.

Conclusions

Based on empirical data from the HOST-EXAM trial, clopidogrel monotherapy was projected to lead to reduced QALYs compared with aspirin during the chronic maintenance period after PCI. These results were affected by a numerically higher rate of cardiovascular mortality in clopidogrel monotherapy reported from the HOST-EXAM trial. (Harmonizing Optimal Strategy for Treatment of Coronary Artery Stenosis-Extended Antiplatelet Monotherapy [HOST-EXAM]; NCT02044250).

Acute coronary artery stent thrombosis caused by a spasm: A case report

BACKGROUND

Acute stent thrombosis (AST) is a serious complication of percutaneous coronary intervention (PCI). The causes of AST include the use of stents of inappropriate diameters, multiple overlapping stents, or excessively long stents; incomplete stent expansion; poor stent adhesion; incomplete coverage of dissection; formation of thrombosis or intramural hematomas; vascular injury secondary to intraoperative mechanical manipulation; insufficient dose administration of postoperative antiplatelet medications; and resistance to antiplatelet drugs. Cases of AST secondary to coronary artery spasms are rare, with only a few reports in the literature.

CASE SUMMARY

A 55-year-old man was admitted to the hospital with a chief complaint of back pain for 2 d. He was diagnosed with coronary heart disease and acute myocardial infarction (AMI) based on electrocardiography results and creatinine kinase myocardial band, troponin I, and troponin T levels. A 2.5 mm × 33.0 mm drug-eluting stent was inserted into the occluded portion of the right coronary artery. Aspirin, clopidogrel, and atorvastatin were started. Six days later, the patient developed AST after taking a bath in the morning. Repeat coronary angiography showed occlusion of the proximal stent, and intravascular ultrasound showed severe coronary artery spasms. The patient’s AST was thought to be caused by coronary artery spasms and treated with percutaneous transluminal coronary angioplasty. Postoperatively, he was administered diltiazem to inhibit coronary artery spasms and prevent future episodes of AST. He survived and reported no discomfort at the 2-mo follow-up after the operation and initiation of drug treatment.

CONCLUSION

Coronary spasms can cause both AMI and AST. For patients who exhibit coronary spasms during PCI, diltiazem administration could reduce spasms and prevent future AST.

Clopidogrel Versus Aspirin Monotherapy Following Dual Antiplatelet Therapy After Percutaneous Coronary Intervention: A Systematic Review and Meta-analysis

BACKGROUND

Current guidelines recommend 6 to 12 months of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) followed by aspirin monotherapy indefinitely. We aimed to assess the efficacy and safety of clopidogrel versus aspirin in the post-PCI population after completing DAPT.

METHODS

We systematically searched five electronic databases to identify studies comparing clopidogrel with aspirin following completion of DAPT after PCI. We pooled outcomes for major adverse cardiac events (MACE), cardiac death, all-cause death, major bleeding, myocardial infarction (MI), and stroke.

RESULTS

We included five studies with 13,850 patients, of whom 5601 (40.4%) received clopidogrel. Mean follow-up was 12-36 months. All patients received drug-eluting stents. Duration of DAPT before antiplatelet monotherapy was 1-18 months. Clopidogrel was associated with reductions in MACE (Risk ratio [RR] 0.78, 95% confidence interval [CI] 0.66-0.92), any stroke (RR 0.51; 95% confidence interval [CI] 0.35-0.76), ischemic stroke (RR 0.55; 95% CI 0.32-0.94), and hemorrhagic stroke (RR 0.24; 95% CI 0.09-0.68) when compared with aspirin. Cardiac death (RR 0.87; 95% CI 0.53-1.41), all-cause death (RR 1.06; 95% CI 0.81-1.39), major bleeding (RR 0.74; 95% CI 0.43-1.29), MI (RR 1.01; 95% CI 0.64-1.60), repeat revascularization (RR 0.88; 95% CI 0.71-1.09), target vessel revascularization (RR 0.76; 95% CI 0.52-1.13), and stent thrombosis (RR 0.96; 95% CI 0.35-2.59) were not significantly different among groups.

CONCLUSION

Compared with aspirin, clopidogrel was associated with reductions in MACE and stroke (ischemic and hemorrhagic) following DAPT completion after PCI. There were no significant differences in mortality, major bleeding, MI, and repeat revascularization between groups.