Acute occlusions after percutaneous transluminal coronary intervention occur in about 5% of cases. The incidence of these serious adverse events may be reduced by the identification of risk factors, appropriate indication for the intervention, and by medical
therapy with antiplatelets and
antithrombins. The medical management of complications during percutaneous transluminal interventions also may include thrombolytics.
Aspirin has been shown to significantly reduce the incidence of procedure-related
coronary occlusion and ischaemic events. Available data suggest pre-treatment with 250-500 mg followed by 100-300 mg
aspirin after the intervention.
Ticlopidine seems to be equally effective; however, because of its side effects it should be used only in cases of a contra-indication to
aspirin. The second indispensable therapeutic concept in the prevention of acute thrombotic events during PTCA is
thrombin inhibition. The level of anticoagulation achieved by
heparin seems to be critically important. Therefore the recommendation for
heparin dosing is a bolus of 10,000 U followed by an
intravenous infusion over 24 h of either 1000 U.h-1 or an infusion adjusted to keep the aPTT above 3 times control, but lower doses of shorter duration may be equally effective in uncomplicated cases. Prolonged pre-treatment with
heparin may be useful if the pre-intervention angiogram is suggestive of intracoronary
thrombus. Thrombolysis as an adjunct to PTCA did not reduce the rate of periprocedural
coronary occlusions, but pre-treatment with thrombolysis may be useful in patients with recanalization of occluded vein grafts or in patients with large amounts of thrombotic material. In acute
coronary occlusion, thrombolysis has rarely been used as a sole rescue
therapy and results have not been encouraging, although a thrombotic process often is involved. Thrombolysis as an adjunct to rescue angioplasty showed no better clinical outcome than prolonged balloon inflation or stenting. Because of serious
bleeding complications, thrombolysis should only be considered as a treatment option if
thrombosis is unequivocally the major cause of the acute occlusion.