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Improving the safety and efficacy of robotically assisted mitral valve surgery

December 1, 2017|Cleveland Clinic Journal of Medicine
Stephanie Mick, MD
Author and Disclosure Information

Stephanie Mick, MD
Cardiac Surgeon and Surgical Director, TAVR, Heart & Vascular Institute, Cleveland Clinic

Correspondence: Stephanie Mick, MD, Surgical Director, TAVR, Heart & Vascular Institute, J4-1, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH; micks@ccf.org.

This article is based on Dr. Mick’s presentation at the Sones/Favaloro Scientific Program, “Transforming the Delivery of Cardiovascular Care: Research and Innovation in the Heart & Vascular Institute,” held in Cleveland, OH, November 18, 2016. It was also presented at the American Association for Thoracic Surgery. The article was drafted by Cleveland Clinic Journal of Medicine and was then reviewed, revised, and approved by Dr. Mick.

Dr. Mick reported no financial interest or relationships that pose a potential conflict of interest with this article.

ABSTRACT

To improve outcomes with robotically assisted mitral valve surgery, Cleveland Clinic conducted a study evaluating outcomes in 1,000 consecutive cases. Primary areas of interest were to determine whether increased surgical experience with robotic techniques improved outcomes and to identify opportunities that could improve procedural processes. Results showed that these surgeries were effective and safe in terms of improvements in procedure time, transfusion rates, stroke risk, number of mitral valve replacements, and number of conversions to sternotomy. The development and implementation of a patient-selection algorithm halfway through the study further improved outcomes by refining patient eligibility criteria. This study showed that use of a focused preoperative assessment with an algorithm-driven patient selection process combined with increased technical expertise can enhance outcomes with robotic mitral valve surgery.

KEY POINTS

  • Surgeon competence with robotic techniques, which can be improved through experience, is a key to improving outcomes.
  • This patient-selection algorithm provides an evidence-based approach to identifying patients who are the best candidates for the robotic approach.
  • This study showed that increased surgical competence and improved patient selection improved patient outcomes for the primary end points.

PROCEDURAL IMPROVEMENTS 

A primary point of interest was to identify procedural improvements that occurred during the course of the study. The areas evaluated in robotically assisted mitral valve surgery were the efficacy of the procedure in time, transfusion rates, stroke risk, how many mitral valve replacements occurred, and how many required conversion to sternotomy. These were assessed to determine whether surgical experience resulted in improvement.

Results showed that those efficiencies improved during the study. Cardiopulmonary bypass time decreased from about 140 minutes to 130 minutes. Cross-clamp time improved more dramatically from about 110 minutes to 90 minutes. And the percentage of cases requiring postoperative or intraoperative blood transfusion improved from about 24% to 10%.

PATIENT SELECTION CRITERIA: ALGORITHM

Figure 1. Algorithm for determining patient eligibility for the robotic approach to mitral valve repair.1
After 500 cases, enough data had been collected to create an algorithm for determining which patients would be eligible for mitral valve repair via the robotic approach vs a sternotomy-based approach. Use of the algorithm (Figure 1) relies on results from echocardiography and computed tomography (CT) for most of the selection process. Echocardiography results that indicate a sternal approach would be preferred include significant aortic insufficiency, which complicates cardioplegia delivery, severe mitral annulus calcification, left ventricular dysfunction, and pulmonary hypertension. CT results are important in assessing patients for aortoiliac atherosclerosis, femoral artery diameter, and pectus excavatum. The existence of any of these indicates a patient more appropriate for the sternal approach than the robotic approach.

ALGORITHM IMPACT

What was the effect of this algorithm? In the 500 cases after its implementation, the stroke rate decreased by more than half—from 10 incidents before to 4 incidents after—and mitral replacements dropped from 4 to 0. The rate of conversion from robotic repair to conventional sternotomy in this patient series also improved, although this likely reflects surgical experience more than the algorithm. The conversion rate initially increased as surgeons gained experience with the robotic techniques. It rose to 4% during the first 300 to 400 cases, then dropped to 2% at the 500-case mark. It leveled off for the next 300 cases before dropping to 0 toward the end of the series.

Other metrics improved as well, which were attributed to a combination of surgical experience with robotic assistance and use of the patient-selection algorithm. The stroke risk declined to 0.8%, ischemic and cardiopulmonary bypass times declined, and the transfusion rate declined. No mitral replacements were done in the last 500 cases, and the conversion to conventional sternotomy rate declined to 1%.

In conclusion, this Cleveland Clinic study showed that a combination of a focused preoperative assessment using the patient-selection algorithm and increased surgical experience with robotic techniques enhanced clinical outcomes and improved procedural efficiency associated with robotically assisted mitral valve surgery.

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