A well-developed collateral circulation (CC) is frequently observed in patients with total coronary occlusion. However, the fate of CC after successful coronary angioplasty (PTCA) is not clearly defined. The purpose of this study was to assess the temporal change of CC after successful PTCA of a totally occluded artery using coronary angiography (CA) and myocardial contrast echocardiography (MCE).

The study group comprised 20 consecutive patients (16 male, mean age 54 years) who underwent elective PTCA for total coronary occlusion. CA was performed before, immediately after and 24hrs after PTCA. MCE was performed before, immediately after and 24hrs after PTCA by intracoronary injection of sonicated radiographic contrast medium. According to the angiographic findings, CC was graded on a scale of 0 to 3 as follows. O=no visible filling ; 1 =collateral filling of side branches ; 2=partial collateral filling of the epicardial artery, 3=complete filling of the epicardial artery. On MCE, myocardial perfusion by CC was assessed by scoring the contrast pattern of collateral-dependent myocardial segments as follows . 0, none ; 0.5, patchy or epicardial; or 1, homogenous.

Left anterior descending artery was occluded in 12 patients and right coronary artery in 8 patient. CA collateral grade before PTCA was grade 2 in 5 patients and grade 3 in 15. PTCA with stenting was successfully performed in all patients without significant residual stenosis. CA showed CC disappeared after PTCA in all patients. However, residual collateral perfusion was observed in 7 patients by MCE performed immediately after PTCA (score 1 in 3 patients ; score 0.5 in 4 patients). This residual collateral perfusion could be demonstrated even 24hrs after PTCA by MCE in 3 patients.

Although angiographically not visible, coronary CC may persist even, after successful PTCA of a totally occluded artery. MCE is a useful clinical tool in the evaluation of temporal change of CC after PTCA.