Electrocardiogram-synchronized pulsatile extracorporeal life support preserves left ventricular function and coronary flow in a porcine model of cardiogenic shock.

INTRODUCTION: Veno-arterial extracorporeal life support (ECLS) is increasingly being used to treat rapidly progressing or severe cardiogenic shock. However, it has been repeatedly shown that increased afterload associated with ECLS significantly diminishes left ventricular (LV) performance. The objective of the present study was to compare LV function and coronary flow during standard continuous-flow ECLS support and electrocardiogram (ECG)-synchronized pulsatile ECLS flow in a porcine model of cardiogenic shock. METHODS: Sixteen female swine (mean body weight 45 kg) underwent ECLS implantation under general anesthesia and artificial ventilation. Subsequently, acute cardiogenic shock, with documented signs of tissue hypoperfusion, was induced by initiating global myocardial hypoxia. Hemodynamic cardiac performance variables and coronary flow were then measured at different rates of continuous or pulsatile ECLS flow (ranging from 1 L/min to 4 L/min) using arterial and venous catheters, a pulmonary artery catheter, an LV pressure-volume loop catheter, and a Doppler coronary guide-wire. RESULTS: Myocardial hypoxia resulted in declines in mean cardiac output to 1.7±0.7 L/min, systolic blood pressure to 64±22 mmHg, and LV ejection fraction (LVEF) to 22±7%. Synchronized pulsatile flow was associated with a significant reduction in LV end-systolic volume by 6.2 mL (6.7%), an increase in LV stroke volume by 5.0 mL (17.4%), higher LVEF by 4.5% (18.8% relative), cardiac output by 0.37 L/min (17.1%), and mean arterial pressure by 3.0 mmHg (5.5%) when compared with continuous ECLS flow at all ECLS flow rates (P<0.05). At selected ECLS flow rates, pulsatile flow also reduced LV end-diastolic pressure, end-diastolic volume, and systolic pressure. ECG-synchronized pulsatile flow was also associated with significantly increased (7% to 22%) coronary flow at all ECLS flow rates. CONCLUSION: ECG-synchronized pulsatile ECLS flow preserved LV function and coronary flow compared with standard continuous-flow ECLS in a porcine model of cardiogenic shock.

Pulsatile venoarterial perfusion using a novel synchronized cardiac assist device augments coronary artery blood flow during ventricular fibrillation.

Patients with cardiogenic shock have a very high mortality. Here we report the first use of a percutaneous pulsatile cardiac assist device, based on a diagonal pump synchronized with the heart cycle by means of an electrocardiographic signal in adult pigs. Eight domestic pigs underwent mandatory ventilation. During sinus rhythm, there were no differences between pulsatile and nonpulsatile perfusion with regard to pulmonary artery pressure, pulmonary wedge pressure, central venous pressure, mean arterial pressure (MAP), mean pulse pressure, and mean coronary artery flow (CAF). After 2 min of complete cardiac arrest (ventricular fibrillation), circulatory support with the i-cor in venoarterial nonpulsatile extracorporeal membrane oxygenation (ECMO) mode (3 L/min) restored systemic circulation, with an increase of MAP to 78.3 mm Hg and CAF to 5.27 mL/min. After changing from ECMO settings to pulsatile mode (3 L/min, 75 bpm, pulse amplitude range 3500 rpm), MAP did not change significantly (75.6 mm Hg); however, CAF increased to 8.45 mL/min. After changing back to nonpulsatile mode, MAP remained stable (83.6 mm Hg), but CAF decreased to 4.85 mL/min. Thereafter, pulsatile cardiac assist was established with a reduced blood flow of 2.5 L/min, and the pulse amplitude range was extended to 4500 rpm. Under these conditions, MAP remained stable (71.0 mm Hg), but CAF significantly increased to 15.2 mL/min (P < 0.05). Percutaneous cardiac support using a venoarterial cardiac assist device equipped with a novel diagonal pump is able to restore and increase systemic and coronary circulation during ventricular fibrillation. Electrocardiographically triggered synchronized cardiac assist provides an additional increase of coronary artery flow. These promising results are to be confirmed in humans.