Coronary angioplasty (PTCA) using prolonged balloon inflation has obviated emergency coronary bypass surgery in some patients with acute occlusions at the time of PTCA. However, the use of prolonged balloon inflations has not been shown to improve long-term restenosis rates. As an alternative to the passive autoperfusion catheter, we evaluated a hemoperfusion system in which blood was obtained from the side arm of an arterial sheath and infused through the central lumen of standard balloon catheters via a modified Medrad IV pump during balloon inflation. PTCA was performed in 71 male patients (median age 57 yr). The median balloon inflation time was 4.8 minutes and the median rate of blood perfusion was 30 ml/min. PTCA was successful (lumen increase by 20 percentage points) in 83% of patients (59/71) with diameter stenosis decreasing from a median 82% to 30%. Emergency coronary bypass was required in four patients (5%). Angiographic data for six-month followup was available on 37 patients. The restenosis rate (loss of 50% of gain) was 46% (17/37). The conclusion is that prolonged balloon inflation angioplasty has a role in complicated PTCA but offers no advantage in improving long-term restenosis rates in elective PTCA.