J M A Swinburn1, R Senior. 1. Department of Cardiovascular Medicine, Northwick Park Hospital, Harrow, UK.
Abstract
AIMS: Power pulse inversion echocardiography is a new technique by which contrast microbubbles can be visualised in real time within the myocardium, enabling simultaneous assessment of myocardial function and microvascular integrity, which is a prerequisite for myocardial viability. We aimed to determine whether microvascular integrity using power pulse inversion can be used to predict contractile reserve early after myocardial infarction. METHODS AND RESULTS: We studied 19 stable patients 5.1(1.6) days after presentation using low dose dobutamine stress echocardiography and power pulse inversion using slow bolus intravenous injections of Optison. A 16-segment left ventricular model was used to define wall thickening at baseline and following low dose dobutamine infusion (1, normal; 2, reduced; 3, absent), and contrast opacification (1, homogeneous; 2, heterogenous or reduced; 3, absent). The techniques were compared on a segment-by-segment basis to determine whether microvascular integrity (contrast opacification score of 1 or 2) could predict contractile reserve (any improvement during low dose dobutamine infusion) in segments that were akinetic at rest. Follow-up echocardiography was performed one month later. RESULTS: Ninety-four (31%) of the 304 segments were akinetic at rest, and 22 (23%) of these demonstrated contractile reserve. In 87 (92%) of the resting akinetic segments contrast opacification could be adequately determined, and of these 20 (23%) showed microvascular integrity. The negative and positive predictive value of microvascular integrity for determining contractile reserve was 90% and 65%, respectively, and 92% and 59% respectively for predicting recovery of function. CONCLUSION: Power pulse inversion can be used at rest to determine myocardial function and simultaneously to predict contractile reserve of akinetic segments in patients early after myocardial infarction. This technique has the potential to provide a bedside assessment of myocardial viability.
AIMS: Power pulse inversion echocardiography is a new technique by which contrast microbubbles can be visualised in real time within the myocardium, enabling simultaneous assessment of myocardial function and microvascular integrity, which is a prerequisite for myocardial viability. We aimed to determine whether microvascular integrity using power pulse inversion can be used to predict contractile reserve early after myocardial infarction. METHODS AND RESULTS: We studied 19 stable patients 5.1(1.6) days after presentation using low dose dobutamine stress echocardiography and power pulse inversion using slow bolus intravenous injections of Optison. A 16-segment left ventricular model was used to define wall thickening at baseline and following low dose dobutamine infusion (1, normal; 2, reduced; 3, absent), and contrast opacification (1, homogeneous; 2, heterogenous or reduced; 3, absent). The techniques were compared on a segment-by-segment basis to determine whether microvascular integrity (contrast opacification score of 1 or 2) could predict contractile reserve (any improvement during low dose dobutamine infusion) in segments that were akinetic at rest. Follow-up echocardiography was performed one month later. RESULTS: Ninety-four (31%) of the 304 segments were akinetic at rest, and 22 (23%) of these demonstrated contractile reserve. In 87 (92%) of the resting akinetic segments contrast opacification could be adequately determined, and of these 20 (23%) showed microvascular integrity. The negative and positive predictive value of microvascular integrity for determining contractile reserve was 90% and 65%, respectively, and 92% and 59% respectively for predicting recovery of function. CONCLUSION: Power pulse inversion can be used at rest to determine myocardial function and simultaneously to predict contractile reserve of akinetic segments in patients early after myocardial infarction. This technique has the potential to provide a bedside assessment of myocardial viability.