Intra‐Aortic Balloon Pump Support in the Isolated Beating Porcine Heart in Nonischemic and Ischemic Pump Failure

Abstract

The blood pressure changes induced by the intra-aortic balloon pump (IABP) are expected to create clinical improvement in terms of coronary perfusion and myocardial oxygen consumption. However, the measured effects reported in literature are inconsistent. The aim of this study was to investigate the influence of ischemia on IABP efficacy in healthy hearts and in shock. Twelve slaughterhouse porcine hearts (hearts 1-12) were connected to an external circulatory system, while physiologic cardiac performance was restored. Different clinical scenarios, ranging from healthy to cardiogenic shock, were simulated by step-wise administration of negative inotropic drugs. In hearts 7-12, severe global myocardial ischemia superimposed upon the decreased contractile states was created. IABP support was applied in all hearts under all conditions. Without ischemia, the IABP induced a mild increase in coronary blood flow and cardiac output. These effects were strongly augmented in the presence of persisting ischemia, where coronary blood flow increased by 49 ± 24% (P < 0.01) and cardiac output by 17 ± 6% (P < 0.01) in case of severe pump failure. As expected, myocardial oxygen consumption increased in case of ischemia (21 ± 17%; P < 0.01), while it slightly decreased without (-3 ± 6%; P < 0.01). In case of progressive pump failure due to persistent myocardial ischemia, the IABP increased hyperemic coronary blood flow and cardiac output significantly, and reversed the progressive hemodynamic deterioration within minutes. This suggests that IABP therapy in acute myocardial infarction is most effective in patients with viable myocardium, suffering from persistent myocardial ischemia, despite adequate epicardial reperfusion.

Early clinical outcomes of on-pump beating-heart versus off-pump technique for surgical revascularization in patients with severe left ventricular dysfunction: the experience of a single center

“…Although most proponents of off-pump surgery have advocated the off-pump technique as a suitable strategy for surgical revascularization, patients with severe left ventricular dysfunction undergoing off-pump CABG surgery are at risk for intra-operative hemodynamic deterioration and incomplete revascularization, which increases the incidence of postoperative morbidity and mortality [ 8 ]. Even if a combined application of an intra-aortic balloon pump (IABP), morbidity and mortality after off-pump CABG surgery may remain high in patients with severe left ventricular dysfunction due to intra-operative hemodynamic deterioration resulting from inadequate circulatory support (IABP support increases the cardiac output up to approximately 17% in the case of severe pump failure) [ 9 , 10 ].…”

Ultrasound‐based estimation of remaining cardiac function in LVAD‐supported ex vivo hearts

“…This was based on the reduction in CO and mean aortic pressure from baseline, which followed the nonischemic clinical scenario presented in. 25 At Heart condition I, 0 krpm, CO was typically close to 5 L/min, with a mean aortic pressure of 75-85 mm Hg, while in the most degraded condition (Heart condition II for the HM2 hearts and IV for MMD), CO was 3 L/min with a mean aortic pressure of 60 mm Hg. The number of complete datasets (heart conditions) per experiment depended on the rate at which each heart deteriorated, as well as the initial condition of each heart.…”

Investigating the physiology of normothermic ex vivo heart perfusion in an isolated slaughterhouse porcine model used for device testing and training

“…The mean cardiac output and coronary flow rate were measured using two ultrasound flow probes (SonoTT™ Clamp-On Transducer, em-tec GmbH, Finning, Germany), placed after the afterload and the pulmonary artery, respectively. The hemodynamic parameters were continuously monitored and adapted according to the pump function of the heart to fit the optimal clinical scenario as reported in Schampaert, van Nunen [20], shown in Fig. 2.…”

“…Slaughterhouse pig hearts revived in this commercially available isolated heart model have previously shown cardiac output, stroke volume, pressures, valve interactions and dynamic changes that are comparable to those observed in humans [15]. In the last decade, this model has been used to successfully visualize transcatheter aortic valve implantations [16], to assess computer tomographic myocardial perfusions [17], to evaluate magnetic resonance imaging-based 4D flow analysis and to study left ventricular assist devices [18, 19], intra-aortic balloon pump support [20] and coronary autoregulation [21].…”