Immediate Changes of Collateral Function After Successful Recanalization of Chronic Total Coronary Occlusions

Abstract

Background-Coronary collaterals are essential to maintain myocardial function in chronic total coronary occlusions (TCOs). The aim of the present study was to assess the collateral circulation in TCOs before coronary angioplasty and to determine the recruitable collateral perfusion after recanalization by use of intracoronary Doppler flow velocimetry. Methods and Results-In 21 patients with TCOs (duration Ͼ4 weeks), Doppler recordings of basal collateral flow were obtained before the first balloon inflation. Angioplasty was performed with stent implantation in all lesions. At the end of the procedure, recruitable collateral flow was measured during a repeat balloon inflation. The collateral flow index (CFI) was calculated from the velocity integral during the occlusion/velocity integral of antegrade flow. In 17 of 21 patients, angiography was repeated after 24 hours, and CFI was reassessed. Average peak velocity of collateral flow was 10.9Ϯ5.6 cm/s with a predominantly systolic flow (diastolic/systolic velocity ratio Ͻ0.5) compared with antegrade flow (diastolic/systolic velocity ratio Ͼ1.5). After recanalization, the average peak velocity of recruitable collateral flow dropped by Ͼ50% to 4.7Ϯ2.5 cm/s. CFI fell from 0.48Ϯ0.25 to 0.21Ϯ0.16 (PϽ0.001). There was no further change of CFI during the following 24 hours. CFI was higher in patients with preserved regional ventricular function than in those with akinetic myocardium (0.57Ϯ0.23 versus 0.38Ϯ0.12, PϽ0.05). Conclusions-Collateral

Regression of Collateral Function After Recanalization of Chronic Total Coronary Occlusions

“…The principal inclusion criterion was that this assessment was possible before the first balloon inflation. 20 Other inclusion criteria were a duration of the occlusion Ͼ2 weeks; TIMI grade 0 coronary flow; spontaneously visible collaterals; and no ventricular aneurysm supplied by the occluded artery. The study protocol had been approved by the institutional ethics committee.…”

“…[15][16][17][18][19] Applying these invasive methods in CTOs, we had recently shown a loss of collateral function within 30 minutes after recanalization. 19, 20 The present study should assess whether collaterals regress or remain preserved several months after recanalization. Possible clinical determinants of collateral regression could be diabetes mellitus, 21 the regional left ventricular (LV) function and prior MI 19 or angiographic factors such as collateral anatomy and size, 22 and the incidence of restenosis or reocclusion.…”

Direct Assessment of Coronary Steal and Associated Changes of Collateral Hemodynamics in Chronic Total Coronary Occlusions

“…17 After the lesion was crossed by a 0.014-inch guide wire, an over-the-wire exchange catheter (Transit, Cordis) or low-profile balloon catheter (Ranger, Scimed) was advanced distal to the occlusion. The guide wire was exchanged for a pressure recording wire (PressureWire, RADI Medical Systems).…”

“…All Doppler flow signals were measured manually, as previously described. 17 The velocity integral during systole and diastole and the duration of systole and diastole were measured to calculate the average peak velocity (APV). A collateral flow index (CFI) was calculated before recanalization and during the final balloon occlusion as the ratio of distal APV/antegrade APV, the latter obtained at the same location after PTCA.…”

“…14 -16 These studies during balloon occlusion in the course of a percutaneous transluminal coronary angioplasty (PTCA) of nonocclusive lesions do not represent the hemodynamic situation in a totally collateral-dependent myocardium of a chronic total coronary occlusion (TCO), because there is a considerable difference between the baseline collateral function before recanalization and recruitable collateral function during balloon occlusion. 17, 18 The present study should assess, for the first time, the effect of pharmacologic vasodilation on collateral-dependent coronary flow distal to the occluded lesion and determine the hemodynamic changes of the collateral circulation associated with coronary steal and its relation to clinical parameters and angiographic collateral anatomy.…”