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Beating Heart Mitral Valve Surgery: Innovation or Back to the Past?

We read with interest the paper by Masroor S, Dance G, and Angeli SJ entitled “Beating heart video-assisted mitral valve surgery: A useful technique for high-risk patients.”1 These authors suggest that video-assisted beating heart mitral valve surgery can offer excellent outcomes in high-risk patients, combining the benefits of a minimally invasive access and the advantages of myocardial continuous perfusion, and we completely agree with this statement. In our opinion, their article raises some interesting issues that we would like to comment on. Beating heart video-assisted mitral valve surgery is a very attractive technique, with several advantages. Nevertheless, it can be complicated by air embolism, because standard de-airing maneuvers cannot be performed. In addiction, back bleeding from the aorta, especially in the case of associated aortic regurgitation, can interfere with surgical view, sometimes compromising the outcome of valve repair. Masroor and colleagues adopted this technique on a patient needing a first cardiac operation. Why did they prefer this option? Which are their suggested indications to this procedure? In our experience, as well as in other centers,2 this approach shows its own best in intricate situations such as complex redo operations, particularly in patients with previous patent grafts. In these cases, avoidance of extensive surgical dissection, no need for aortic cross-clamping, and cardioplegia delivery simplify otherwise difficult and risky procedures. Interestingly, we found that patients who underwent mitral valve surgery in a minimally invasive fashion and without cardioplegic arrest after previous heart surgery had lower levels of lactates and of CPK-MB when compared to a matched population in terms of sex, age, mitral disease, previous cardiac surgery, and type of operation, who underwent mitral surgery through median sternotomy with aortic cross-clamp and cold blood cardioplegic arrest. This suggests reduced myocardial ischemic damage and better organ perfusion. As the authors state in the comment section, air embolism is a major risk of this approach. Did the authors adopt any diagnostic tool for detection of intraoperative embolism, particularly at the cerebral level? We believe that cerebral monitoring with near-infrared spectroscopy (NIRS) and transcranial Doppler could be of help in these situations and that, in their absence, moderate hypothermia rather than normothermia should be preferred. In addition, normothermia reduces organ protection from hypothetical adverse events and requires full pump flow that can increase back bleeding. Another technical aspect that requires attention is the use of an additional vent in the left ventricle at the end of valve repair. Rarely, it could be the cause of profuse uncontrolled bleeding due to wall tears, hardly manageable through a right mini-thoracotomy and often requiring conversion to median sternotomy. In conclusion, minimally invasive beating heart mitral surgery can be considered an effective and safe approach for selected categories of patients. The characteristics and principles of this technique, currently considered an innovation but actually based on concepts debated decades ago, reflect, in our opinion, a wise jump to the past of our science.