Abstract 9037: Hemodynamics and Myocardial Blood Flow Patterns Following Placement of a Cardiac Passive Restraint Device in a Model of Dilated Cardiomyopathy
Background: While cardiac passive restraint devices (CPRDs) can favorably affect LV function with dilated cardiomyopathy (DCM), the effects on a critical determinant of myocardial function, blood flow, remain unclear. Accordingly, this study examined a prototypical CPRD (HeartNetTM, Paracor) in a clinically relevant model of DCM.
Methods: Pigs with DCM (n=10, 3 weeks pacing 240 bpm) were instrumented to measure hemodynamics, including cardiac output (CO) and mean arterial pressure (MAP), and LV myocardial blood flow (microspheres) under baseline steady state conditions and following adenosine infusion (1.5 μmol/kg/min) to determine coronary flow reserve. Measurements were performed before and after CPRD placement.
Results: LV myocardial blood flow increased from baseline steady state with adenosine (Figure 1), consistent with epicardial coronary vasodilation. The CPRD was then placed and applied an estimated epicardial pressure of 1.4 mmHg which did not cause hemodynamic compromise compared to pre-CPRD (CO 2.5±0.4 vs 2.3±0.3 L/min, respectively, p=0.68 and MAP 86±6 vs 98±8 mmHg, respectively, p=0.24). LV steady state myocardial blood flow tended to increase with CPRD placement (p=0.18), however coronary flow reserve was significantly blunted (Figure 1). By ANOVA modeling, the LV epicardial free wall region was most affected (F=6.21, p=0.02).
Conclusions: These unique findings demonstrated in a clinically relevant DCM model that acute CPRD placement did not adversely affect hemodynamics or basal myocardial blood flow. However, CPRD placement blunted the increase in adenosine induced myocardial blood flow suggesting that epicardial transmural pressure can alter myocardial blood flow patterns through influences on epicardial coronary vasodilation in the context of DCM.
- © 2010 by American Heart Association, Inc.