Mitral Valve Surgery: Right Thoracotomy Approach

INTRODUCTION

One of the more time-tested alternative, nonsternotomy approaches to the mitral valve is through a right thoracotomy. Over time, this approach has evolved into a minimally invasive technique through a “port access” right anterior minithoracotomy. While various strategies exist for cannulation, cardioprotection, aortic cross-clamping, and exposure of the mitral valve, the basic tenants of peripheral cannulation and a more anatomic approach to the mitral valve offer several advantages. First, such less-invasive approaches have been shown to decrease postoperative pain, decrease need for blood transfusion, and decreased length of stay. ^, Additionally, this approach allows for evaluation and testing of the mitral valve in the natural, anatomic orientation of the mitral annulus, which theoretically can increase the likelihood of repair. The right thoracotomy approach also offers a distinct advantage in patients who have had a previous sternotomy as it typically requires less adhesiolysis and less need for blood products. Several challenges are also conferred by this approach, including cannulation, cardioprotection, aortic cross-clamping, and visualization. Herein, we present our preferred right anterior minithoracotomy port-access technique with thoracoscopic assistance and highlight the challenges and solutions to common problems this technique affords.

COMPARISON OF RIGHT THORACOTOMY TO STERNOTOMY

The mini-right thoracotomy approach to the mitral valve first gained popularity in the late 1990s. ^, Despite several decades of experience, only 25% of isolated mitral operations were undertaken through minimally invasive approaches as of 2009. Compared to sternotomy, patients undergoing minimally invasive operations had comparable rates of stroke and mortality while requiring fewer reoperations for postoperative hemorrhage and had shorter length of stay. ^, While patients in the minimally invasive cohort in this study had longer cardiopulmonary bypass and aortic cross-clamp times, these importantly did not result in an increase in morbidity or mortality.

Additionally, the lateral approach to the mitral valve allows for evaluation of the mitral valve in a more anatomic position than when approached via sternotomy. This allows for testing of the repaired valve with minimal distortion of the geometry of the mitral apparatus and has, in our experience, facilitated repairs with no residual regurgitation. While there was no reported increase in reoperation, patients with mild residual mitral regurgitation (MR) after repair were shown to have more frequent progression to moderate (17% vs. 7%, P = .03) or severe (6% vs. 1%, P =.016) regurgitation as compared to patients with no residual MR, suggesting that these small differences in residual MR improve long-term outcomes.

Furthermore, avoidance of sternotomy also avoids potential sternal wound complications and may decrease postoperative pain. ^{, ,} While pain following thoracotomy certainly can prove significant, adjuncts such as indwelling local anesthetic catheters, intercostal nerve cryoablation, and intercostal nerve block with long-acting local anesthetics have been shown to significantly decrease postoperative pain after thoracotomy. As part of a multimodal, multidisciplinary approach, institution of “enhanced recovery” pathways, which include the intraoperative use of such adjuncts, have been shown to decrease postoperative morphine equivalents, length of stay and hospital cost in patients undergoing general thoracic surgery by thoracotomy. The study of such pathways in minimally invasive cardiac surgery remains ongoing.

While not rising to the level of importance of the quality of the operation performed, it should also be mentioned that overall cosmesis from port-access mitral surgery is generally excellent, consisting of a single 3 to 6 cm incision of the right anterolateral chest that can often be placed in the inframammary fold in women, and a 1 to 2 cm femoral incision to allow for cannulation for cardiopulmonary bypass. Avoidance of a sternotomy may be particularly advantageous in frail patients. Additionally, patient perception of minimally invasive techniques remains positive, and demand for such operations remains high with both referring cardiologists and patients alike.

Finally, our described strategy for direct visualization of the operation through a well-placed right thoracotomy aided by placement of a thoracoscopic port allows for the surgeon, the trainee, and the assistant to have excellent, simultaneous visualization of the operative field. This allows for ease of demonstration of technique (“watch the way I do this”) and supervised practice (“let me watch you do this”), which can be difficult without the use of a thoracoscope or with open mitral surgery.

SET UP