Neonatal piglet model of intraaortic balloon pumping: Improved efficacy using echocardiographic timing

Background. Pediatric intraaortic balloon pumping (IABP) has met with littl e success because of technical difficulty in tracking rapid heart rates. Th is study was designed to evaluate the efficacy of M-mode echocardiography f or IABP timing in a neonatal piglet model. Methods. Two groups of piglets underwent mitral valve avulsion to create a model of shock. Group 1 (n = 8; mean weight, 7.7 +/- 1.8 kg) underwent IABP timed with both the ascending aortic pressure and M-mode echocardiogram. G roup 2 (n = 6; mean weight, 7.5 +/- 1.4 kg) underwent two separate periods of IABP: one with echocardiographic timing and the second using standard ti ming points from the femoral arterial pressure tracing and electrocardiogra m. Measurements included ascending aortic now, left anterior descending art erial now, ascending aortic pressure, left atrial pressure, and heart rate. Results. Mitral valve avulsion produced a shock model with a significant de crease in mean aortic pressure and aortic now and a significant increase in left atrial pressure and heart rate. Compared with the shock state, IABP i n group 1 animals resulted in a significant increase in aortic now (353 +/- 152 versus 454 +/- 109 mL/min; p < 0.05) and a significant decrease in lef t atrial pressure (23 +/- 6 versus 17 +/- 7 mm Hg; p < 0.05). Group 2 anima ls with echocardiogram-timed IABP had significantly increased aortic flow ( 365 +/- 106 versus 458 +/- 107 mL/min; p < 0.05) and mean aortic pressure ( 43 +/- 11 versus 52 +/- 8 mm Hg; p < 0.05). However, standard-timed IABP fa iled to show any improvement. Conclusions. In piglets with rapid heart rates, echocardiogram-timed IABP r esults in increased aortic flow and pressure and decreased left atrial pres sure compared with standard-timed IABP. (C) 1998 by The Society of Thoracic Surgeons.