Left ventricular outflow tract obstruction with mitral valve replacement in small ventricular cavities |
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| Authors: | G K Jett M D Jett G R Barnhart G L van Rijk-Swikker M Jones R E Clark |
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| Affiliation: | 1. Department of Cardiology, Kasr El Aini Hospital, Faculty of Medicine, Cairo University, Egypt;2. Division of Cardiology, Department of Medicine, University of California San Diego, La Jolla, California;3. Department of Pediatrics, University of California San Diego, La Jolla, California;4. Department of Pediatrics, Rady Children''s Hospital San Diego, San Diego, California;5. Department of Cardiology, Sharp Memorial Hospital and San Diego Cardiac Center, San Diego, California;1. Laboratório de Neuropsicofarmacologia, Departamento de Farmacologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil;2. Departamento de Farmacologia, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil;3. Departmento de Nutrição, Escola de Enfermagem, Universidade Federal de Minas Gerais Belo Horizonte, MG, Brazil;4. Laboratório de Fisiologia Cardiovascular, Departmento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil;5. Laboratório de Neurofarmacologia, Departmento de Farmacologia, Universidade Federal de Minas Gerais Belo Horizonte, MG, Brazil;1. Department of Cardiology, Montefiore Medical Center, New York, New York;2. University Heart Center, University Hospital Zurich, Zurich, Switzerland |
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| Abstract: | The inference that mitral valve replacement (MVR) may produce left ventricular outflow tract (LVOT) obstruction has been made, but no comparative hemodynamic studies with various types of prostheses have been done. The purpose of the present study was to compare the gradients created across the LVOT with MVR in young sheep with small left ventricular cavities. Mitral valve replacement was accomplished using cardiopulmonary bypass and hypothermic cardioplegic arrest. Five animals were used for each of the following valves studied: 25-mm Ionescu-Shiley bovine pericardial valve, 25-mm Hancock porcine aortic valve, 2M-6120 28-mm Starr-Edwards ball-valve prosthesis, 25-mm Björk-Shiley 60-degree flat tilting-disc prosthesis, and 25-mm St. Jude Medical hemidisc valve. Gradients across the LVOT were measured after MVR and then during infusion of isoproterenol hydrochloride (0.05 μ/kg/min). Following MVR, only the Starr-Edwards valve produced an LVOT gradient (32 ± 23 mm Hg). Substantial gradients after MVR were seen, however, with isoproterenol administration with the Ionescu-Shiley (47 ± 4 mm Hg), Hancock (13 ± 8 mm Hg), and Starr-Edwards (65 ± 30 mm Hg) valves but not with the low-profile valves (Björk-Shiley and St. Jude Medical). The results of the present study demonstrate that MVR can produce LVOT obstruction. The greatest degree of obstruction was with the high-profile mechanical and bioprosthetic valves. |
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