Effects of Intra-Aortic Balloon Pump delayed deflation timing on carotid blood flow and cardiac mechanics: An ultrasound and haemodynamic study

Abstract

Intra-Aortic Balloon Pump (IABP) efficacy is critically affected by the inflation/deflation timing. Balloon deflation may cause a sucking effect, and a steal phenomenon on carotid flow. Delaying IABP deflation reduces the degree of this flow reversal, but at the same time exposes patients to the risk of increased proto-systolic afterload with detrimental effects on the LV. The purpose of this study was to investigate the effects of a delayed IABP deflation timing on cerebral blood flow and LV hemodynamics, by means of simultaneous carotid artery ultrasonography, trans-thoracic echocardiography and central aortic pressure analysis. Delaying IABP deflation trigger to the beginning of QRS effectively increased the cerebral blood flow by 20%, mostly by reducing the reverse component flow caused by the diastolic balloon deflation. Extending the deflation to the early systole was safe and favourably impacted on cardiac mechanics, increasing CO by 15% without prolonging LV isovolumetric contraction and ejection phases.