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Minimally Invasive Versus Conventional Open Mitral Valve Surgery: A Meta-Analysis and Systematic Review

Cheng, Davy C. H. MD*; Martin, Janet PharmD, MSc (HTA&M)*†; Lal, Avtar MD, PhD*; Diegeler, Anno MD, PhD‡; Folliguet, Thierry A. MD§; Nifong, L. Wiley MD∥; Perier, Patrick MD‡; Raanani, Ehud MD¶; Smith, J. Michael MD#; Seeburger, Joerg MD**; Falk, Volkmar MD††

Innovations: Technology & Techniques in Cardiothoracic & Vascular Surgery: March/April 2011 - Volume 6 - Issue 2 - pp 84-103
doi: 10.1097/IMI.0b013e3182167feb
Original Article

Objective: This meta-analysis sought to determine whether minimally invasive mitral valve surgery (mini-MVS) improves clinical outcomes and resource utilization compared with conventional open mitral valve surgery (conv-MVS) in patients undergoing mitral valve repair or replacement.

Methods: A comprehensive search of MEDLINE, Cochrane Library, EMBASE, CTSnet, and databases of abstracts was undertaken to identify all randomized and nonrandomized studies up to March 2010 of mini-MVS through thoracotomy versus conv-MVS through median sternotomy for mitral valve repair or replacement. Outcomes of interest included death, stroke, myocardial infarction, aortic dissection, need for reintervention, and any other reported clinically relevant outcomes or indicator of resource utilization. Relative risk and weighted mean differences and their 95% confidence intervals were analyzed as appropriate using the random effects model. Heterogeneity was measured using the I2 statistic.

Results: Thirty-five studies met the inclusion criteria (two randomized controlled trials and 33 nonrandomized studies). The mortality rate after mini-MVS versus conv-MVS was similar at 30 days (1.2% vs 1.5%), 1 year (0.9% vs 1.3%), 3 years (0.5% vs 0.5%), and 9 years (0% vs 3.7%). A number of clinical outcomes were significantly improved with mini-MVS versus conv-MVS including atrial fibrillation (18% vs 22%), chest tube drainage (578 vs 871 mL), transfusions, sternal infection (0.04% vs 0.27%), time to return to normal activity, and patient scar satisfaction. However, the 30-day risk of stroke (2.1% vs 1.2%), aortic dissection/injury (0.2% vs 0%), groin infection (2% vs 0%), and phrenic nerve palsy (3% vs 0%) were significantly increased for mini-MVS versus conv-MVS. Other clinical outcomes were similar between groups. Cross-clamp time, cardiopulmonary bypass time, and procedure time were significantly increased with mini-MVS; however, ventilation time and length of stay in intensive care unit and hospital were reduced.

Conclusions: Current evidence suggests that mini-MVS maybe associated with decreased bleeding, blood product transfusion, atrial fibrillation, sternal wound infection, scar dissatisfaction, ventilation time, intensive care unit stay, hospital length of stay, and reduced time to return to normal activity, without detected adverse impact on long-term need for valvular reintervention and survival beyond 1 year. However, these potential benefits for mini-MVS may come with an increased risk of stroke, aortic dissection or aortic injury, phrenic nerve palsy, groin infections/complications, and increased cross-clamp, cardiopulmonary bypass, and procedure time. Available evidence is largely limited to retrospective comparisons of small cohorts comparing mini-MVS versus conv-MVS that provide only short-term outcomes. Given these limitations, randomized controlled trials with adequate power and duration of follow-up to measure clinically relevant outcomes are recommended to determine the balance of benefits and risks.

From the *Department of Anesthesia & Perioperative Medicine, Evidence-Based Perioperative Clinical Outcomes Research Group (EPiCOR), London Health Sciences Centre, University of Western Ontario, London, ON Canada; †High Impact Technology Evaluation Centre, London Health Sciences Centre, London, ON Canada; ‡Division of Cardiothoracic Surgery, Herz-und Gefasse Klinik Bad Neustadt, Bad Neustadt, Germany; §Département de Pathologie Cardiaque, L'Institut Mutualiste Montsouris, Paris, France; ∥Department of Cardiothoracic Surgery, East Carolina University School of Medicine, Greenville, NC USA; ¶Sheba Medical Center, Tel Hashomer, Tel Aviv, Israel; #Cardiac, Vascular & Thoracic Surgeons, Inc., Cincinnati, OH USA; **Klinik für Herzchirurgie, Herzzentrum der Universität Leipzig, Leipzig, Germany; and ††Klinik für Herz- und Gefässchirurgie, Universitätsspital Zürich, Zurich, Switzerland.

Accepted for publication December 31, 2010.

Supported by The International Society for Minimally Invasive Cardiothoracic Surgery (ISMICS), which has received unrestricted educational grants from industries that produce surgical technologies; and by the Evidence-Based Perioperative Clinical Outcomes Research Group (EPiCOR), Department of Anesthesia & Perioperative Medicine, University of Western Ontario, London, ON Canada.

Disclosures: J. Michael Smith, MD, serves as a scientific advisor to Intuitive Surgical, Inc., Sunnyvale, CA USA; AtriCure, West Chester, OH USA; Edwards LifeSciences, Irvine, CA USA; and Ethicon Endo-Surgery, Inc., Cincinnati, OH USA. He is on the Speakers Bureau of Intuitive Surgical and Edwards LifeSciences. He receives no royalties or stipends from any company. Volkmar Falk, MD, is a speaker and receives consulting fees for Medtronic, Inc., Minneapolis, MN USA; St. Jude Medical, St. Paul, MN USA; Symetis, Lausanne, Switzerland; and Valtech Cardio, Or Yehuda, Israel.

Address correspondence and reprint requests to Davy C. H. Cheng, MD, LHSC-University Hospital, 339 Windermere Road, C3-172, London, ON Canada N6A 5A5. E-mail:

© 2011 Lippincott Williams & Wilkins, Inc.