Draft Key Questions
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Archived: This report is greater than 3 years old. Findings may be used for research purposes, but should not be considered current.
To describe the types of prosthetic heart valves now in use and in development, summarize clinical studies completed or under way, and discuss factors that may impact clinical outcomes for percutaneous heart valve (PHV) replacement.
MEDLINE®, EMBASE®, and gray literature sources.
We searched the English-language literature to identify systematic reviews and comparative clinical studies of conventional heart valves and studies of PHVs in adults. We define PHV replacement as the delivery of a prosthetic heart valve via a catheter inserted either through a vein or artery (femoral vein; femoral, subclavian, or axillary arteries; or the ascending aorta) or through the apex of the heart via an incision in the chest wall (transapical approach).
We identified numerous mechanical and bioprosthetic heart valves. Six systematic reviews compared various conventional valves; the single high-quality review found better short-term hemodynamic performance but longer operating times with stentless compared to stented bioprosthetic valves. A large primary literature (57 randomized controlled trials [RCTs], 40 observational studies) compares various conventional heart valves.
Seven manufacturers of PHVs were identified in 62 fully published case reports or non-comparative case series that studied 856 unique patients. All but 19 of these patients received valves produced by one of two PHV manufacturers. The route of access was via the femoral artery in 580 patients (68 percent). The transapical approach was used in 223 patients (26 percent). The route of access for the remaining 53 patients (6 percent) was via the femoral vein, subclavian artery, axillary artery, or ascending aorta. All but two of the prosthetic valves were implanted in the aortic valve position in patients with symptomatic aortic stenosis at high operative risk. Successful implantation was achieved in 92 percent of patients; 30-day survival was 86 percent. The lack of comparative studies limits the ability to determine which variables associated with PHV replacement are causally related to outcomes. A multicenter RCT comparing PHV to conventional heart valve replacement or medical management is currently underway in the United States.
A large number of heart valve prostheses are in use, but there are limited data to inform the selection of one valve over another. There is sufficient existing primary literature to support systematic reviews or meta-analyses to help inform several important clinical questions pertaining to conventional heart valve replacement. PHV replacement is a rapidly emerging technology that has been proven feasible and is a promising therapeutic option for patients with severe, symptomatic aortic stenosis who have a higher risk of poor outcome with surgical aortic valve replacement. Well-designed observational studies and decision modeling could help inform clinical and health policy in the absence of RCTs.