Regional left ventricular function during transient coronary occlusion: relation with coronary collateral flow

Objective: To test the hypothesis that regional left ventricular (LV) function during balloon angioplasty is related to the amount of collateral flow to the ischaemic region. Design: Prospective study. Setting: Tertiary referral centre. Methods: In 50 patients with coronary artery disease and without myocardial infarction, regional systolic and diastolic LV function was determined using tissue Doppler ultrasound (TD) before and at the end of a 60 second occlusion of a stenotic lesion undergoing percutaneous transluminal coronary angioplasty (PTCA) through a pressure guidewire. The study population was subdivided into a group with collaterals insufficient (n = 33) and one with collaterals sufficient (n = 17) to prevent ECG ST shifts suggestive of myocardial ischaemia during PTCA. Pulsed TD was performed from an apical window in the myocardial region supplied by the vessel being treated by PTCA. Pressure derived collateral flow index (CFI) was determined by simultaneous measurement of mean aortic (P-ao) and distal intracoronary occlusive pressures (P-occl), where CH = (P-occl - 8)/(P-oc - 8). Results: At 60 seconds of occlusion, several parameters of systolic and diastolic TD derived LV long axis function were significantly different between the groups. Also, there was a significant correlation between regional systolic excursion velocity, early diastolic excursion velocity, regional isovolumetric relaxation time, and CFI. Conclusion: During brief coronary artery occlusions, regional systolic and diastolic LV function is directly related to the amount of collateral flow to this territory.