Acute Left Ventricular Unloading in Dogs With Chronic Heart Failure: Continuous Aortic Flow Augmentation Versus Intra-Aortic Balloon Pumping

Abstract 

Background

Continuous aortic flow augmentation (CAFA) therapy with the Cancion System (Orqis Medical, Inc) was shown to effectively unload the left ventricle in dogs with chronic heart failure (HF). This study compared the extent of acute left ventricular (LV) unloading elicited by CAFA to that elicited by intra-aortic balloon counterpulsation (IABP) in normotensive dogs with coronary microembolization-induced HF.

Methods and Results

Seven HF dogs were studied with both CAFA and IABP in random order and 1 week apart. In both instances, active therapy was maintained for 4hours. The Cancion system was positioned using a dual femoral approach configuration with a constant pump flow of 250mL/min. In all dogs and with both devices, LV end-diastolic pressure (EDP), LV end-systolic volume (ESV), and LV ejection fraction (EF) were measured at baseline and at 2 and 4hours after instituting CAFA or IABP. Plasma samples obtained at the end of 4hours of therapy were used to measure a host of circulating biomarkers that included neurohormones, cytokines, and A-type and B-type natriuretic peptides. IABP had no significant effects on LVEDP, LVESV, and LVEF. In contrast, CAFA significantly decreased LVEDP and LVESV and increased LVEF. Compared with IABP, CAFA was accompanied by significant improvements in circulating levels of neurohormones, cytokines, and natriuretic peptides.

Conclusions

The results indicate that CAFA is more effective than IABP in achieving acute global LV unloading in dogs with chronic HF not complicated by ongoing myocardial ischemia or cardiogenic shock.

Key Words: Congestive heart failure, ventricular dilation, ventricular function, plasma biomarkers, ventricular unloading