双倍负荷量氯吡格雷更有效地抑制血小板聚集

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Double Loading Dose of Clopidogrel Enhances Platelet Inhibition
By Scott Baltic

NEW YORK (Reuters Health) Mar 14 - A double bolus of clopidogrel -- two 600-mg doses given 24 hours apart -- provides greater platelet inhibition than conventional loading doses in patients undergoing percutaneous coronary intervention (PCI), according to a clinical trial by Canadian researchers.
纽约（路透社健康）3月14日：根据加拿大研究者的临床试验，PCI（经皮冠脉介入术）病人接受双倍剂量的氯吡格雷，即每24小时内分别两次给予600mg的负荷量，比传统负荷量能更有效抑制血小板聚集。
The study, the largest to date comparing clopidogrel loading regimens, is reported in the March 18 issue of the Journal of the American College of Cardiology.
这项研究将发表在3月18日的美国心脏病学会杂志上。
Dr. Philippe L. L'Allier and colleagues at the Montreal Heart Institute and Universite de Montreal, Quebec, point out that single loading doses of up to 900 mg of clopidogrel prior to PCI have failed to attain significantly greater platelet inhibition than a 600-mg loading dose. They also note that the effect of two separate 600-mg loading doses of clopidogrel given 18-24 hours apart had not previously been reported.
Dr. Philippe L. L'Allier和他在蒙特利尔心脏研究所Montreal Heart Institute及魁北克蒙特利尔大学Universite de Montreal, Quebec工作的同事指出，PCI术前单次给予900mg的氯吡格雷，并不比单次600mg负荷剂量更有效。他们同时指出，18-24小时内分别两次给与600mg的负荷剂量的效果以前从未有过报道。
The study cohort consisted of 148 patients admitted to the hospital for suspected or documented coronary artery disease. All underwent elective coronary angiography and PCI as appropriate.
这项研究包括148名怀疑或已确诊冠心病的住院病人。所有病人都根据需要接受了CAG（冠脉造影）或PCI术。
The subjects were randomly assigned to one of three clopidogrel regimens. Group A received 300 mg the day before the procedure, plus 75 mg the morning of the procedure; Group B, 600 mg the morning of the procedure; and Group C, 600 mg the day before, plus 600 mg the morning of the procedure. Day-before doses were at least 15 hours before the procedure, and same-morning doses were at least 2 hours before the procedure.
这项研究将病人随机分成接受不同剂量的3组。A组术前接受300mg每日的剂量，术晨用75mg。B组术晨接受600mg的剂量。C组术前日接受600mg的剂量，术晨用600mg。术前日的给药时间与手术时间至少相隔15小时。术晨给药时间与手术时间至少相隔2小时。
Although the nurses administered the various doses in an open-label fashion, the technicians who performed the platelet aggregation studies remained blinded to group assignments.
给药护士知道病人分组，但监测血小板凝聚功能的技师并不知道。
Percent inhibition of peak platelet aggregation was consistently better in Group C than in the other two groups, the investigators report.
研究人员称C组病人的血小板聚集峰的抑制百分比始终好于另外两组。
In addition, they noted that patients in Group C experienced significantly less resistance to clopidogrel.
研究同时指出，C组病人对氯吡格雷耐药也显著减少。
Regarding the potential clinical impact of widespread adoption of the double loading dose approach in patients undergoing coronary angiography and possible PCI, Dr. L'Allier told Reuters Health: \"A reasonable assumption is that 600-mg double loading dose would decrease cardiovascular death/MI/urgent target vessel revascularization by at least 25%-40% in the medium term.\"
考虑到该研究可能使CAG或PCI的病人接受双倍剂量氯吡格雷的做法被广泛采用，Dr. L'Allier告诉路透社健康：“合理的假设是：近期内，双次600mg负荷剂量可能将心血管性死亡、心梗、急诊血管再通减少25%-40%。”
J Am Coll Cardiol 2008;51:1066-1072.
美国心脏病学会杂志 2008;51:1066-1072