Key result
Sequential intracoronary microsphere embolization reduces sheep LVEF by ~33 points, establishing a stable HF model.
Why the study?
A stable ovine model of congestive heart failure is needed to study long-term effects of cardiac assist devices due to similarities with human heart size and circulation.
Provides stable ovine HF model for device testing; extends preclinical options but leaves human translation open.
Similarities in coronary circulation and heart size of sheep to that of humans are specific advantages of a sheep model of congestive heart failure (CHF). CHF was created in 11 sheep (51 +/- 4 kg) by selective sequential intracoronary injection of 90 microns microspheres under 1.5% isoflurane anesthesia. Hemodynamic characteristics were assessed at baseline, 4 weeks after establishment of CHF (ejection fraction [EF] < 35%, n = 11), and 26 weeks (n = 7) later. Baseline echocardiographic EF was 59 +/- 5% and fell to 26 +/- 5% after 5 +/- 2 embolizations. The left ventricular (LV) pressure-volume relationship showed stable decreases in LV end-systolic elastance (Ees) and preload recruitable stroke work. Intravenous infusion of dobutamine increased Ees from 2.8 +/- 1.7 to 4.3 +/- 2.2 and 4.5 +/- 1.4 mmHg/ml at heart rates of 140 and 160/min, respectively, at baseline. Increases of Ees (from 1.3 +/- 0.5 to 2.3 +/- 0.7 and 1.9 +/- 0.5 mmHg/ml at heart rates of 140 and 160/min, respectively) with dobutamine under CHF conditions did not exceed Ees values at baseline without dobutamine. This response to dobutamine infusion did not change 26 weeks after establishment of CHF. This stable ovine CHF model is proposed for studies on the long-term effects of cardiac assist devices.
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Huang et al. (1997) studied Congestive Heart Failure (n=11). Selective sequential intracoronary injection of 90 microns microspheres vs. Baseline was evaluated on Ejection fraction. Sequential intracoronary injection of 90-micron microspheres in sheep successfully created a stable congestive heart failure model, reducing ejection fraction from 59% at baseline to 26%.
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