Abstract 15974: Salutary Effects of a Novel Implantable Counterpulsation Assist Device on Left Ventricular Mechanoenergetics in a Porcine Model of Acute Heart Failure

Introduction: We have developed the Pressure Unloading Left Ventricular Assist Device (PULVAD), a novel implantable counterpulsation LVAD, designed to provide LV pressure unloading with augmentation of LV performance and retention of pulsatility. We assessed the effects of PULVAD on hemodynamics, LV mechanoenergetics and myocardial perfusion in a porcine model of acute heart failure (aHF). Methods: PULVAD comprises a pneumatically-driven pumping chamber implanted in the thoracic cavity and connected to the ascending aorta. PULVAD is ECG-synchronized and operates under the counterpulsation principle: deflation of the device air chamber just prior and during systole draws blood from the aorta into the device blood chamber, while inflation of the device air chamber during diastole ejects blood from the device blood chamber into the aorta. Seven farm pigs were instrumented with Millar catheter, sonomicrometry crystals and a Doppler flow probe placed around the left anterior descending artery (LAD). Pigs underwent PULVAD implantation and induction of aHF by LAD ligation for 60 minutes, followed by reperfusion. PULVAD was driven by a standard intra-aortic balloon pump console. Hemodynamics, indices of LV mechanoenergetics and LAD blood flow were measured without and after brief (<60 secs) PULVAD support during reperfusion. Results: PULVAD support induced a profound reduction of LV afterload (systolic aortic pressure decreased by 19.2 mmHg and end-diastolic aortic pressure decreased by 22.3 mmHg). PULVAD support improved the mechanical performance of the failing LV (increased ejection fraction by 4.2%, cardiac output by 0.3 l/min and maximum elastance by 0.74 mmHg/ml). The PULVAD concurrently decreased LV energy consumption (stroke work decreased by 16% and pressure volume area decreased by 25%) and optimized LV energetic performance (improved the ratio of stroke work to pressure volume area from 52.8% to 59.0%). PULVAD support increased mean coronary blood flow by 34%, through dramatic augmentation (66%) of diastolic blood flow. Conclusions: The PULVAD unloads the failing LV, optimizes LV mechanoenergetics and augments coronary blood flow. These salutary effects of short-term PULVAD support provide the foundation for long-term testing.