Standard versus high loading doses of clopidogrel in Asian ST-segment elevation myocardial infarction patients undergoing percutaneous coronary intervention: insights from the Korea Acute Myocardial Infarction Registry

Impact of Double Loading Regimen of Clopidogrel on Final Angiographic Results, Incidence of Upper Gastrointestinal Bleeding and Clinical Outcomes in Patients with STEMI Undergoing Primary Coronary Intervention

This study tested the therapeutic impact of double-loading dose (i.e., 600 mg) versus standard-loading dose (i.e., 300 mg) of clopidogrel on ST-segment-elevation-myocardial-infarction (STEMI) patients undergoing primary-coronary-intervention (PCI).Between January 2005 and December 2013, a total of 1461 STEMI patients undergoing PCI were consecutively enrolled into the study and categorized into group 1 (600 mg/clopidogrel; n = 508) and group 2 (300 mg/clopidogrel; n = 953). We assessed angiographic thrombolysis-in-myocardial-infarction (TIMI) flow in the infarct-related-artery, 30-day mortality and upper-gastrointestinal-bleeding (UGIB) within 30 days as primary-endpoints and later incidents of UGIB as secondary-endpoints.The results showed that the incidences of advanced Killip score (defined as ≥ score 3) upon presentation (23.8% versus 24.6%) and advanced heart failure (defined as ≥ NYHAFc-3) (10.2% versus 10.4%) did not differ between groups 1 and 2 (all P > 0.4). Primary-endpoints, which were final TIM-3 flow (91.3% versus 91.7%) in the infarct-related-artery, incidences of 30-day mortality (5.8% vs. 7.1%), and UGIB ≤ 30 day (7.8% versus 8.9%) did not differ between group 1 and group 2 (all P > 0.33). The secondary-endpoints which were incidences of ≥ 30-day < one-year (5.2% versus 4.7) and > one-year (8.9% versus 10.1%) UGIB did not differ between groups 1 and 2 (all P > 0.45). One-year mortality did not differ between two groups (10.74% versus 12.9%) (P > 0.25). Multiple-stepwise-logistic-regression analysis showed that age and advanced-Killip score were independently predictive of 30-day mortality (all P < 0.001).Double-loading dose of clopidogrel did not confer an additional benefit to the final angiograph results, 30-day/one-year clinical outcomes; and age and advanced Killip-score were powerful predictors of 30-day mortality.

Outcome comparison of 600 mg versus 300 mg loading dose of clopidogrel for patients with ST-elevation myocardial infarction: a meta-analysis

BACKGROUND

A 600-mg loading dose (LD) of clopidogrel has been shown to be superior to a 300-mg LD in inhibiting platelet function. However, data for clinical superiority are limited, and there is a paucity of adequately powered randomized trials investigating this issue. This meta-analysis was performed to determine the optimal LD of clopidogrel in ST-elevation myocardial infarction patients treated with primary percutaneous coronary intervention.

METHODS

A meta-analysis of controlled trials and observational studies was performed comparing 600-mg with 300-mg LDs of clopidogrel. The primary efficacy end point was a major adverse cardiac event (MACE), and the primary safety end point was major bleeding. Data were extracted on an intention to treat basis. The X2 test was used to evaluate heterogeneity. A random effects model was used, and odds ratios (OR) were calculated using the Mantel-Haenszel method.

RESULTS

Nine studies involving 18 623 patients were included in the efficacy analysis. Mean duration of follow-up was 8 months. Four studies were eligible for the safety analysis. The MACE risk was lower with a 600-mg LD (7.0% [650/9231]) than with a 300-mg LD (9.2% [867/9392]; OR, 0.75; 95% CI, 0.63-0.91). On the other hand, there was no significant difference in the major bleeding events between the 2 groups (2.5% [89/3551] with 600 mg vs 2.3% [63/2796] with 300 mg; OR, 0.84; 95% CI, (0.60-1.16).

CONCLUSIONS

In ST-elevation myocardial infarction patients treated with primary percutaneous coronary intervention, administration of a 600-mg LD of clopidogrel is associated with a lower risk of MACE than is administration of a 300-mg LD, without increasing the risk of major bleeding.

The scientific achievements of the decades in Korean Acute Myocardial Infarction Registry

The Korea Acute Myocardial Infarction Registry (KAMIR) was the first nationwide registry data collection designed to track outcomes of patients with acute myocardial infarction (AMI). These studies reflect the current therapeutic approaches and management for AMI in Korea. The results of KAMIR could help clinicians to predict the prognosis of their patients and identify better diagnostic and treatment tools to improve the quality of care. The KAMIR score was proposed to be a predictor of the prognosis of AMI patients. Triple antiplatelet therapy, consisting of aspirin, clopidogrel and cilostazol, was effective at preventing major adverse clinical outcomes. Drug-eluting stents were effective and safe in AMI patients with no increased risk of stent thrombosis. Statin therapy was effective in Korean AMI patients, including those with very low levels of low density cholesterol. The present review summarizes the 10-year scientific achievements of KAMIR from admission to outpatient care during long-term clinical follow-up.

New horizons of acute myocardial infarction: from the Korea Acute Myocardial Infarction Registry

As the first nationwide Korean prospective multicenter data collection registry, the Korea Acute Myocardial Infarction Registry (KAMIR) launched in November 2005. Through a number of innovative approaches, KAMIR suggested new horizons about acute myocardial infarction (AMI) which contains unique features of Asian patients from baseline characteristics to treatment strategy. Obesity paradox was existed in Korean AMI patients, whereas no gender differences among them. KAMIR score suggested new risk stratifying method with increased convenience and an enhanced accuracy for the prediction of adverse outcomes. Standard loading dose of clopidogrel was enough for Asian AMI patients. Triple antiplatelet therapy with aspirin, clopidogrel and cilostazol could improve clinical outcomes than dual antiplatelet therapy with aspirin and clopidogrel. Statin improved clinical outcomes even in AMI patients with very low LDL-C levels. The rate of percutaneous coronary intervention was higher and door-to-balloon time was shorter than the previous reports. Zotarolimus eluting stents as the 2nd generation drug-eluting stent (DES) was not superior to the 1st generation DES, in contrast to the western AMI studies. KAMIR made a cornerstone in the study of Korean AMI and expected to be new standards of care for AMI with the renewal of KAMIR design to overcome its pitfalls.

Impact of Clopidogrel loading dose in patients with chronic kidney disease undergoing primary percutaneous coronary intervention for ST-segment elevation myocardial infarction

The optimal loading dose of clopidogrel in patients with chronic kidney disease who undergo primary percutaneous coronary intervention for ST-segment elevation myocardial infarction has not been investigated. The aim of this study was to assess the impact of clopidogrel loading dose on clinical outcomes in this setting. A total of 1,457 patients with CKD (estimated glomerular filtration rate <60 ml/min/1.73 m(2)) were evaluated according to clopidogrel loading dose: 600 mg (n = 861) versus 300 mg (n = 596). In-hospital complications, including major bleeding and clinical outcomes at 1 and 12 months, were compared between the 2 groups. The in-hospital major bleeding rate was similar (0.8% vs 0.2%, p = 0.09). Also, there were no differences in major adverse cardiac event rates, including death, recurrent myocardial infarction, target lesion revascularization, and stent thrombosis, at 1 month (15.6% vs 16.4%, p = 0.70) and 12 months (19.0% vs 21.3%, p = 0.32). On multivariate analysis, a 600-mg loading dose of clopidogrel was not an independent predictor of 1-month (odds ratio 1.13, 95% confidence interval 0.49 to 2.57, p = 0.78) and 12-month (odds ratio 0.89, 95% confidence interval 0.52 to 1.51, p = 0.66) major adverse cardiac events. After propensity score-matched analysis, these results were unchanged. In conclusion, a 600-mg loading dose of clopidogrel was not effective in reducing 1- and 12-month major adverse cardiac events in patients with chronic kidney disease who underwent primary percutaneous coronary intervention for ST-segment elevation myocardial infarction, but this dose did not increase the in-hospital major bleeding rate.

Effects of 600 mg versus 300 mg loading dose of clopidogrel in Asian patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention: long-term follow-up study

PURPOSE

The optimum loading dose of clopidogrel has not been established in Asian patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). Our aim was to evaluate the impact of different clopidogrel loading doses on short- and long-term clinical outcomes in Asian STEMI patients undergoing primary PCI.

MATERIALS AND METHODS

We studied 691 STEMI patients undergoing primary PCI, loaded with 600 mg (n=381) or 300 mg (n=310) of clopidogrel. The primary outcome was major adverse cardiac events (MACEs), defined as a composite of all-cause death, reinfarction, or target vessel revascularization (TVR).

RESULTS

Baseline clinical and peri-procedural characteristics were mostly comparable between the 600 mg and 300 mg groups. There were no differences in 1 month MACEs as well as all-cause death, reinfarction, TVR, and stent thrombosis between the two groups. After a median follow-up of 921 days, MACEs [adjusted hazard ratio (HR) for the 600 mg group 1.79, 95% confidence interval (CI): 0.80-3.97, p=0.153], all-cause death (adjusted HR for the 600 mg group 0.97, 95% CI: 0.50-1.88, p=0.928), reinfarction (adjusted HR for the 600 mg group 1.03, 95% CI: 0.55-1.91, p=0.937), and TVR (adjusted HR for the 600 mg group 1.36, 95% CI: 0.68-2.69, p=0.388) did not differ between the two groups. These results were reliable even after analysis of propensity score-matched population, and were also constant among various subgroups.

CONCLUSION

A 600 mg loading dose of clopidogrel did not result in better short- and long-term clinical outcomes in Asian STEMI patients undergoing primary PCI.

Quantitative comparison of clopidogrel 600 mg, prasugrel and ticagrelor, against clopidogrel 300 mg on major adverse cardiovascular events and bleeding in coronary stenting: synthesis of CURRENT-OASIS-7, TRITON-TIMI-38 and PLATO

The convention of loading with clopidogrel 300 mg before coronary intervention may be due for change, but to what? Newer antiplatelet agents may offer better outcomes, at some financial cost. Disappointingly for decision-making clinicians, head-to-head comparisons for the newer alternatives are not available. We systematically review and compare the three alternative strategies: clopidogrel 600 mg, prasugrel and ticagrelor. A total of 14 studies have compared these strategies with the long-standing convention of 300 mg. Throughout this analysis, we consistently report incremental costs and consequences using clopidogrel 300 mg as the reference strategy. Risk ratios for major adverse cardiovascular events at 30 days were 0.74 (95% confidence interval 0.66-0.82, p=0.002) for clopidogrel 600 mg, 0.78 (0.69-0.89; p<0.001) for prasugrel and 0.88 (0.77-1.00; p=0.045) for ticagrelor. All-cause mortality risk ratios were 0.87 (0.74-1.03) with clopidogrel 600 mg, 0.95 (0.78-1.16) with prasugrel and 0.78 (0.69-0.89) with ticagrelor. TIMI major bleeding has risk ratio 0.92 (0.74-1.16; p=0.85) with clopidogrel 600 mg, 1.32 (1.03-1.16; p=0.03) with prasugrel and 1.25 (1.03-1.53; p=0.03) with ticagrelor. Incremental cost for the first year was £0.32 (US$0.50, €0.40) with clopidogrel 600 mg, £608 (US$977, €709) with prasugrel and £665 (US$1068, €775) with ticagrelor. All three strategies have shown a similar reduction in MACE at 30 days by comparison to clopidogrel 300 mg. All three strategies offer progressive benefit, most marked with Ticagrelor. Whether this is worth both the risk of non-compliance with twice-a-day dosing in real-life patients lacking the same motivation as their trial-volunteer counterparts, and the 2000-fold difference in incremental cost, is the remaining matter for debate.