Ej. Topol et al., RECOMBINANT HIRUDIN FOR UNSTABLE ANGINA-PECTORIS - A MULTICENTER, RANDOMIZED ANGIOGRAPHIC TRIAL, Circulation, 89(4), 1994, pp. 1557-1566
Background Coronary artery thrombosis plays an important pathophysiolo
gical role in unstable angina and non-Q-wave myocardial infarction. To
date, heparin and thrombolytic therapy has not provided complete or c
onsistent benefit. We hypothesized that recombinant hirudin, a direct
thrombin inhibitor, would prevent accumulation of coronary artery thro
mbus in a manner superior to heparin. Methods and Results Patients wit
h rest ischemic pain, abnormal ECG, and baseline angiogram indicating
a greater than or equal to 60% stenosis of a culprit coronary artery o
r saphenous vein graft with visual appearance of thrombus were randomi
zed to one of two different doses of heparin (either a target activate
d partial thromboplastin time aPTT of 65 to 90 or 90 to 110 seconds)
or one of four doses of hirudin (0.05, 0.10, 0.20, or 0.30 mg.kg(-1).
h(-1) infusion) in a dose-escalating protocol. After 72 to 120 hours o
f study drug, a repeat coronary angiogram was obtained, and the paired
studies underwent quantitative analysis. The primary end point was ch
ange in the average cross-sectional area of the culprit lesion. Other
efficacy end points also involved changes in culprit lesion dimensions
and TIMI flow grade. Recombinant hirudin led to a dose-dependent elev
ation of aPTT that appeared to plateau at the 0.2-mg/kg dose. A higher
proportion of hirudin-treated patients had their aPTT within a 40-sec
ond range (16% heparin versus 71% hirudin, P<.001), Overall, the 116 p
atients treated with hirudin tended to show more improvement than the
50 patients receiving heparin relative to the primary efficacy variabl
e-the average cross-sectional area (P=.08)-as well as minimal cross-se
ctional area (P=.028), minimal luminal diameter (P=.029), and percent
diameter stenosis (P=.07). Conclusions Recombinant hirudin appears to
be a promising antithrombotic intervention compared with heparin for i
nhibition of coronary artery thrombus. Large-scale comparative trials
are warranted.