Experimental study of renal sympathetic nerve activity during left ventricular assist device pumping.

To determine the effect of left ventricular assist device (LVAD) pumping on sympathetic tone, renal sympathetic nerve activity (RSNA) was recorded in acute animal experiments. Our TH-7B pneumatically driven sac type ventricular assist device (VAD) was used in 7 adult mongrel dogs. RSNA was detected by use of bipolar electrodes attached to the left renal sympathetic nerve under conditions of various LVAD pumping modes. All hemodynamic data and the RSNA were calculated with a personal computer system. In general, LVAD assistance produced increased systolic aortic pressure, increased pulmonary artery flow and decreased left atrial pressure, which caused decreased RSNA, especially in the counterpulsation mode. These results suggest that renal vascular resistance might be reduced in parallel with the decrease of RSNA. Thus, counterpulsation mode LVAD assistance has the more evident effect in preventing acute prerenal renal failure.