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Ann Thorac Surg 2001;71:1453
© 2001 The Society of Thoracic Surgeons
a Department of Thoracic and Cardiovascular Surgery, The Cleveland Clinic Foundation, 9500 Euclid Ave, Desk F25, Cleveland, OH 44195, USA
e-mail: smedirn{at}ccf.org
How to best manage prosthetic valves and native valve dysfunction in patients requiring mechanical support is unclear. Rao and colleagues report their experience in 199 patients of which 18 had some type of valve intervention during left ventricular assist device (LVAD) implant and outline a reasonable management paradigm in these complex patients. In practice the two questions that need to be answered are: (1) How to reduce the risk of thromboemboli in the presence of a prosthetic valve; and (2) What regurgitant valves should be fixed, how best to fix them and what are the potential risks involved?
Mechanical mitral valves will likely add little risk to LVAD support assuming good right ventricular (RV) function, with high flows across the valve, along with therapeutic anticoagulation. However these factors are not guaranteed. Replacement with a biologic valve is a reasonable alternative. Excision of the valve is not recommended as a recovering ventricle will generate high (30 mm Hg to 60 mm Hg) pressures contracting against a closed pump inflow valve and closed aortic valve and these pressures will be transmitted to the pulmonary vasculature (one case).
An aortic prosthesis is more problematic. It rarely opens early after LVAD support and thrombosis is likely. Patch closure will eliminate the risk of thromboemboli but will not allow training the heart in a patient who may recover function and eliminates the heart as a back up if the device fails. In our experience an old biologic prosthesis failed early after LVAD support probably related to the increased systolic stress on the leaflets. If prolonged support is anticipated, an old biologic valve should be replaced or patched. This increased systolic load will also likely impact upon the durability of aortic valve repairs in this setting but this remains our first choice in patients with aortic insufficiency.
Should we fix mitral and tricuspid regurgitation? Unfortunately Rao and colleagues don’t provide enough information to answer this question. Although mitral regurgitation persists after LVAD support the hemodynamic significance is minimal. This may not be the case in patients being weaned from the LVAD or in patients with inflow valve regurgitation. Whether an Alfieri stitch alone under normal loading conditions will reduce the mitral regurgitation is unknown. Similarly the impact of eliminating tricuspid regurgitation (assuming an annuloplasty does this) on RV function, pump flows and organ functional recovery are unknown.
Valve pathology should not play a role in determining if a patient should receive mechanical support. Careful evaluation of right ventricular function, indication for support (bridge, permanent and recovery), likely duration of support and the durability and reliability of the pump and pump valves all affect the type of valve intervention. The best approach in each situation remains to be defined.
Related Article
Ann. Thorac. Surg. 2001 71: 1448-1453.
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