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

A Chinese Population Cohort Study

Abstract

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.