THE RELATIONSHIP OF ANTICOAGULATION LEVEL AND COMPLICATIONS AFTER SUCCESSFUL PERCUTANEOUS TRANSLUMINAL CORONARY ANGIOPLASTY

The degree of anticoagulation and its effect on the frequency of abrupt coronary artery closure, coronary ischemia, bleeding complications requiring transfusion, and death were examined in 336 patients after elective percutaneous transluminal coronary angioplasty (PTCA). All patients received a bolus of 10,000 U of heparin at the beginning of the procedure followed by a continuous infusion of 2000 U/hr. At the conclusion of the procedure the infusion was reduced to 1000 U/hr and continued for 18 to 24 hours at which time the heparin infusion was suspended to allow removal of arterial and venous access sheaths. Partial thromboplastin time (PTT) was examined while patients continued to receive the heparin infusion. There was a variable degree of PTT prolongation in response to a standard dose of heparin with a range of 34 seconds to ">150 seconds." Patients were divided into two groups according to the degree of heparin-induced PTT prolongation: group A included 271 patients with PTT greater-than-or-equal-to 3 times the control value, and group B comprised 65 patients with PTT <3 times the control value. Ischemic complications were analyzed on day 1 after PTCA and at hospital discharge. Bleeding complications and mortality were examined only at hospital discharge. There was a significant reduction in the incidence of abrupt coronary artery closure in group A on day 1 (1.5% vs 10.7%, p < 0.001) and at hospital discharge (2.6% vs 10.7%, p < 0.003). There was also a statistically significant reduction in the frequency of coronary ischemic events in group A on day 1 (0.4% vs 9.2%, p < 0.001) and at hospital discharge (1.5% vs 9.2%, p < 0.001). There was no statistical difference in the incidence of bleeding complications requiring transfusion (2.9% vs 4.6%, p = NS) or mortality (0.4% vs 3%, p = NS) between the two groups. Of the 11 ischemic complications in group A, six occurred after suspension of the heparin infusion and therefore at a time of diminished anticoagulation. All ischemic complications observed in group B occurred during continuous infusion of heparin. Thus heparin therapy for 18 to 24 hours with resultant PTT greater-than-or-equal-to 3 times the control value is effective in preventing ischemic complications after elective PTCA without an increase in bleeding complications. It may be necessary to monitor the anticoagulation level after elective PTCA to avoid the risk of inadequate anticoagulation.