Abstract 18188: Reversible Pulmonary Trunk Banding. XI: Myocardial Vascular Endothelial Growth Factor Expression of Young Goats Submitted to Rapid Ventricle Retraining
Introduction: Intermittent systolic overload proved to be superior to traditional PA banding, with a more efficient ventricle hypertrophy, even with less exposure to pressure overload. There is a great interest on the adaptive mechanisms of the retrained ventricle.
Hypothesis: This study sought to assess vascular endothelial growth factor (VEGF) expression in the subpulmonary ventricle (RV) retraining of young goats submitted to continuous versus intermittent systolic overload.
Methods: Twenty one21 young goats were separated into 3 groups: sham (no systolic overload), continuous (continuous systolic overload), and intermittent (four 12-hour periods of systolic overload paired with a 12-hour resting period). During a 96-hour protocol, systolic overload was adjusted to achieve a 0.7 right ventricle/aortic pressure ratio. Hemodynamic evaluations were performed before and after systolic overload every day in the postoperative period. Echocardiograms were obtained in the preoperative period and at the end of protocol. After the study period, the animals were humanely killed for morphologic and vascular endothelial growth factor (VEGF) expression assessment.
Results: Both groups had increased right ventricular and septal masses compared with the sham group (P<0002). Echocardiography revealed a major increase in RV wall thickness in the intermittent group (+129.2%) compared with the continuous group (+58.2%; p< 0.001). There was a negligible but significant increase in water content of RV (continuous: +3.5%, intermittent: +4.6%) and septal masses (both study groups: +3.5%) compared with that in the control group (p<0.002). RV VEGF expression was greater in the RV of the intermittent group (2.89% ± 0.41%) than in the continuous (1.80% ± 0.19%) and the sham (1.43% ± 0.18%) groups (p=0.005). No changes in the VEGF expression were observed in the left ventricle (p = 0.423) and septal masses (p= 0.612).
Conclusions: Intermittent systolic overload promotes a greater neoangiogenesis signaling. The association of RV hypertrophy and increased VEGF expression has important implication on the ability of the heart to adapt to pressure overload by promoting a compensatory growth of the coronary vasculature, allowing for a more efficient hypertrophy.
Author Disclosures: R.S. Assad: None. E.A. Rocha: None. T.A. Meniconi: None. M.D. Abduch: None. L.P. Moreira: None. V.D. Aiello: None. F.B. Jatene: None.
- © 2016 by American Heart Association, Inc.