Postoperative outcomes after minimally invasive mitral valve surgery in patients with a body mass index of 35 and more

Objectives: Obesity is an increasing challenge in cardiac surgery. How to manage patients with a body mass index (BMI) of 35 and more undergoing mitral valve (MV) surgery? Aim of our study was to find out, whether the minimally invasive approach could be a safe alternative to median sternotomy for these patients.

Methods: We performed a retrospective analysis of 89 consecutive patients undergoing minimally invasive mitral valve surgery (MIMV) through a right lateral minithoracotomy, done either isolated (n = 43) or concomitant with tricuspid valve surgery (n = 13), MAZE-procedure (n = 89) and/or closure of PFO (n = 9) between March 2002-May 2012. Decision for MIMV was made after exclusion of a high level of the diaphragm through chest X-ray in all patients and additionally exclusion of thoracal adhesions by CT-scan of the thorax in 24 patients. Mean patient age was 61.6 ± 10.6 years. Average BMI was 38.5 ± 4.4 kg/m2, 40 patients (44.9%) were male, 48 patients (53.9%) in atrial fibrillation, 41 patients (46.1%) had diabetes mellitus, 15 patients (16.9%) pulmonary hypertension of 60 mmHg and more. Average left ventricular ejection fraction was 57.5 ± 13.5% and mean logEuroSCORE 7.45 ± 8.4%. In 6 patients (6.7%) was performed prior cardiac surgery, urgent surgery in altogether 9 patients (10.1%) – 5 patients with active endocarditis, 4 patients with cardial decompensation. Follow up mean duration was 3.2 ± 2.7 years.

Results: Total average operation time was 199.5 ± 56.8 min, mean bypass-time 141 ± 52.8 min and mean cross-clamp time 73.4 ± 35.5 min. MV repair was performed in 66 patients (74.2%).

Conversion to sternotomy was necessary in 5 patients (5.7%) (massive thoracal adhesions and extensive steatosis in 4 patients, acute type B-dissection in one patient). Only in the latter patient a CT-scan of the thorax was performed preoperatively.

Total ventilation time was in average 51.6 ± 101 hours, with a median of 12.5 hours. Discharge was possible in average 14.0 ± 8.5 days after surgery. Overall thirty day mortality was 4.5% (n = 4), in patients with elective surgery (n = 80) it was 2.5% (n = 2). Overall 5-year survival was 78.5 ± 5.8%, for patients with elective surgery 84.3 ± 5.6. During follow up four patients underwent MV reoperation with a 5-year event-free rate of 95.6 ± 2.5%.

Conclusions: MIMV surgery in patients with a BMI of 35 is an encouraging alternative to median sternotomy. Preoperative CT-scan of the thorax should be performed to avoid conversion to sternotomy.