Tom Verbelen1, Daniel Burkhoff2, Keiichiro Kasama3, Marion Delcroix4, Filip Rega3, Bart Meyns3. 1. Department of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium; Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium. Electronic address: tom.verbelen@kuleuven.be. 2. Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, New York. 3. Department of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium; Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium. 4. Respiratory Division, University Hospitals Leuven, Leuven, Belgium; Department of Clinical and Experimental Medicine, University of Leuven, Leuven, Belgium.
Abstract
BACKGROUND: Right ventricular (RV) mechanical support is well described in cases of sudden increase in RV afterload. In cases of chronic RV pressure overload (e.g., pulmonary arterial hypertension), it has rarely been described. METHODS: The pulmonary artery was banded in 18 sheep. In the acute group (n = 9), we immediately implanted a Synergy Pocket Micro-Pump. Blood was withdrawn from the right atrium to the pulmonary artery. In the chronic group (n = 9), this pump was implanted 8 weeks after banding. Hemodynamics and pressure-volume loops were recorded before and 15 minutes after pump activation. RESULTS: Low-flow RV mechanical support significantly improved arterial blood pressure in both groups, but cardiac output only in the acute group. Intrinsic RV contractility was not affected. The RV contribution to the total right-sided cardiac output was 54% ± 8 in the acute group vs 10% ± 13 in the chronic group (p < 1.10-5), indicating a more profound unloading in the latter. Diastolic unloading (reflected by decreases in central venous pressure, end-diastolic pressure and volume, and ventricular capacitance) was successful in both groups. Decreases in pressure-volume area and RV peak pressure reflected successful systolic unloading only in the chronic group. CONCLUSIONS: Low-flow RV mechanical support improved arterial blood pressure in both conditions but caused a more profound unloading in the chronic group. Diastolic unloading was successful in both groups, but systolic unloading was successful only in the chronic group. The potential use of low-flow mechanical support for a chronic pressure overloaded right ventricle warrants further research to assess its long-term effects.
BACKGROUND: Right ventricular (RV) mechanical support is well described in cases of sudden increase in RV afterload. In cases of chronic RV pressure overload (e.g., pulmonary arterial hypertension), it has rarely been described. METHODS: The pulmonary artery was banded in 18 sheep. In the acute group (n = 9), we immediately implanted a Synergy Pocket Micro-Pump. Blood was withdrawn from the right atrium to the pulmonary artery. In the chronic group (n = 9), this pump was implanted 8 weeks after banding. Hemodynamics and pressure-volume loops were recorded before and 15 minutes after pump activation. RESULTS: Low-flow RV mechanical support significantly improved arterial blood pressure in both groups, but cardiac output only in the acute group. Intrinsic RV contractility was not affected. The RV contribution to the total right-sided cardiac output was 54% ± 8 in the acute group vs 10% ± 13 in the chronic group (p < 1.10-5), indicating a more profound unloading in the latter. Diastolic unloading (reflected by decreases in central venous pressure, end-diastolic pressure and volume, and ventricular capacitance) was successful in both groups. Decreases in pressure-volume area and RV peak pressure reflected successful systolic unloading only in the chronic group. CONCLUSIONS: Low-flow RV mechanical support improved arterial blood pressure in both conditions but caused a more profound unloading in the chronic group. Diastolic unloading was successful in both groups, but systolic unloading was successful only in the chronic group. The potential use of low-flow mechanical support for a chronic pressure overloaded right ventricle warrants further research to assess its long-term effects.
Authors: Berend E Westerhof; Nabil Saouti; Willem J van der Laarse; Nico Westerhof; Anton Vonk Noordegraaf Journal: Cardiovasc Res Date: 2017-10-01 Impact factor: 10.787