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Propensity score-matched analysis of aortic valve replacement by mini-thoracotomy.

BACKGROUND AND AIM OF THE STUDY
Although minimally invasive aortic valve replacement (MIAVR) through an anterolateral mini-thoracotomy has been shown to reduce surgical trauma, the technique is utilized only at a few selected heart surgery centers. The study aim was to demonstrate the implementation of a MIAVR program at the Innsbruck Medical University, Austria.


METHODS
Between October 2006 and January 2009, a total of 315 patients underwent elective isolated aortic valve replacement (AVR). Of these patients, 87 (27.6%) received MIAVR, while the remainder (n = 228) underwent 'conventional' AVR by full sternotomy. In the MIAVR group, 76 patients (87%) were cannulated via the femoral artery. The mean EuroSCORE was 5.7 +/- 2.2 in the MIAVR group, and 6.7 +/- 2.9 in the AVR group (p < 0.001). Propensity score matching was used to reduce the impact of treatment selection in the comparison of MIAVR with conventional AVR. The propensity score was used to yield two matched groups by means of a 1:1 sample matching.


RESULTS
The total operative, cardiopulmonary bypass and aortic cross-clamp times were significantly longer in the MIAVR group compared to the matched AVR group. The actuarial one-year survival was 96% in the MIAVR group, and 98% in the propensity-matched AVR group (p = 0.57). Reoperation due to bleeding was necessary in 4.6% of the MIAVR group (four patients, three by mini-thoracotomy) compared to 5.7% in the matched AVR group (n = 5; p = 0.38). A total of six MIAVR patients (6.9%) had complications from the cannulated groin, predominantly lymphatic fistula formation. Additionally, there was a trend towards a higher rate of renal insufficiency in the MIAVR group (p = 0.07).


CONCLUSION
MIAVR can be safely implemented as routine cardiac surgery procedure, although the operative times are significantly longer. The early postoperative outcome was equal to that of the sternotomy approach, but postoperative complications were predominantly associated with femoral cannulation.