Elsevier

Heart, Lung and Circulation

Volume 20, Issue 9, September 2011, Pages 555-565
Heart, Lung and Circulation

Review
Mitral Valve Repair or Replacement for Ischaemic Mitral Regurgitation: A Systematic Review

https://doi.org/10.1016/j.hlc.2011.03.012Get rights and content

A literature review was undertaken according to Cochrane guidelines to identify whether mitral valve repair (MV-Repair) or replacement (MV-Replacement) is more effective in patients with moderate to severe ischaemic mitral regurgitation. The literature suggests MV-Repair may have improved 30-day mortality and long-term survival. All 12 studies identified, however, were non-randomised, retrospective, and at significant risk of bias due to heterogeneous surgical techniques and mismatched patient characteristics. Data describing the need for reoperation were not sufficiently well reported to analyse. Functional outcomes and health-related quality of life were not reported. In conclusion, high-quality randomised comparison of MV-Repair and MV-Replacement is urgently needed.

Introduction

Chronic ischaemic mitral regurgitation (IMR) occurs in up to 40% of patients following myocardial infarction [1], and is a major risk factor for adverse outcomes such as impaired ventricular function or death [2]. The characteristic echocardiographic and macroscopic appearance of IMR is a result of complex changes in the geometry and function of the left ventricle and annulus. This is usually caused by myocardial infarction in the distribution of the circumflex or right coronary artery, producing a variable combination of annular dilatation (Carpentier type I dysfunction) and systolic leaflet restriction (Carpentier type IIIb dysfunction) [3].

Few surgeons would advocate either mitral valve (MV) repair or replacement for mild IMR because coronary artery bypass graft (CABG) alone often results in satisfactory resolution of the mitral regurgitation. Outcomes following CABG alone in patients with mild MVR are only marginally worse than in patients with no mitral regurgitation [4] and it has been estimated that only about 3% of patients will subsequently require admission for congestive heart failure [5].

The difficulty arises in determining the management of patients with moderate or severe IMR as CABG alone does not cure the valve insufficiency in this group. Moderate to severe IMR is associated with significantly reduced survival following CABG [6], [7] and about half of patients with moderate IMR undergoing CABG will require future admission for congestive heart failure [5]. Many surgical groups involved in the study of IMR have advocated doing a randomised trial of CABG alone versus CABG with mitral valve intervention in patients with at least moderate IMR [6], [7], [8]. One recent randomised study has already reported significant improvement in terms of symptoms and reversed remodelling at a mean follow-up of three years following mitral valve repair and CABG compared to CABG alone [9]. Although an improvement in survival has only been demonstrated in case series [10], [11], several other randomised trials are currently recruiting patients (NCT00838786, NCT00806988, NCT00443365, NCT00613548, NCT00919256).

The choice of surgical intervention to treat patients with moderate to severe IMR remains problematic as there is no consensus in the literature about whether MV repair (MV-Repair) or MV replacement (MV-Replacement) is more effective. Consequently, we aimed to review the findings of previous studies which have compared these techniques. Our review aims to estimate whether there are differences between patients with IMR undergoing MV-Repair or MV-Replacement with respect to (a) operative mortality, (b) need for reoperation, (c) survival, (d) function and (e) health-related quality of life (HRQoL).

Section snippets

Literature Search

A literature search was performed in Pubmed, Embase, Ovid and Google Scholar for studies published between 1965 and 2010 without language restriction. The following Medical Subject Headings (MeSH) were used: mitral valve*, replantation*, heart valve prosthesis*, heart valve prosthesis implantation*, ischemia*, myocardial ischemia*, and mitral valve insufficiency*. Complementary searches were also performed with the following free text: “mitral valve repair”, “mitral valve replacement”, and

Eligible Studies

The literature search identified 2032 studies, which were published between 1965 and 2010. On the basis of title and abstracts, 42 articles were obtained and reviewed in full. Twelve articles met the inclusion and exclusion criteria (Fig. 1) [4], [8], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32]. All were retrospective and non-randomised. All studies reported 30-day mortality [4], [8], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], five reported re-operation rates [8]

Discussion

The risk of bias to the included studies precludes robust synthesis of their individual findings quantitatively [33]. Nevertheless, the forest plots (Figure 2, Figure 3) qualitatively suggest that MV-Repair tends to be associated with lower peri-operative mortality and longer survival than MV-Replacement in patients with IMR. HRs calculated for studies adjusted for confounding tended to be more, rather than less, extreme than HRs for unadjusted other studies, but were nevertheless moderately

Conclusion

This review suggests that MV-Repair is associated with lower 30-day mortality and may be associated with improved longer term survival. However, there is considerable uncertainty about this finding because included studies were heterogeneous and at risk of confounding and other biases.

Acknowledgments

No external funding was received for this study. Barnaby Reeves is supported in part by the National Institute for Health Research Bristol Biomedical Research Unit in Cardiovascular Medicine.

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