Collateral Function in Chronic Total Coronary Occlusions Is Related to Regional Myocardial Function and Duration of Occlusion

Abstract

Background-Collateral circulation can maintain myocardial function and viability in chronic total coronary occlusion (TCO). The present study evaluates the relation of myocardial function and duration of occlusion to collateral function. Methods and Results-A total of 50 patients underwent a successful recanalization of a TCO (Ͼ4 weeks' duration).Collateral function was assessed by intracoronary Doppler and pressure recordings before the first balloon inflation and after PTCA had been completed. Collateral function was assessed by Doppler-(CFI D ) and pressure-derived collateral flow indices (CFI P ), as well as indices of collateral (R Coll ) and peripheral resistance (R P ). Patients with normokinesia had lower R Coll (4.9Ϯ2.5 versus 11.8Ϯ8.2 mm Hg · cm Ϫ1 · s Ϫ1 ; Pϭ0.033) and lower R P (3.8Ϯ1.9 versus 6.1Ϯ4.1 mm Hg · cm Ϫ1 · s

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

“…First, coronary steal required well-developed collaterals, 14,16,24 whereas collaterals in group N had a lower CFI, higher R CP , and predominantly a systolic collateral flow pattern, as evidence of reduced collateral function. 18,26 As shown previously, collateral resistance is not negligible. 14,16,18 The assumption that large collaterals, because of a low resistance, would not show steal 25 was confirmed by our study, because large collaterals were only observed in group R but not in group S. The lack of a vasodilatory reserve is demonstrated by the unchanged R P in group S, whereas it was decreased significantly in group R. On the other hand, the higher R P in group N and its lack of response to adenosine could be related to the higher proportion of diabetics with a known prevalence of microvascular dysfunction.…”

“…18,26 As shown previously, collateral resistance is not negligible. 14,16,18 The assumption that large collaterals, because of a low resistance, would not show steal 25 was confirmed by our study, because large collaterals were only observed in group R but not in group S. The lack of a vasodilatory reserve is demonstrated by the unchanged R P in group S, whereas it was decreased significantly in group R. On the other hand, the higher R P in group N and its lack of response to adenosine could be related to the higher proportion of diabetics with a known prevalence of microvascular dysfunction. 27 We did not record directly the coronary pressure in the donor artery at the collateral origin.…”

“…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.…”

Regression of Collateral Function After Recanalization of Chronic Total Coronary Occlusions

“…[12][13][14] The applicability of these data to human pathophysiology is not yet proven, but the advent of direct measurement of collateral function in humans with miniaturized sensors of coronary flow and pressure provides a means to test the experimental data in humans. [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.…”

“…[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.…”