Launching a program of minimally invasive mitral valve surgery

Aim: To evaluate the learning curve of minimally invasive mitral valve surgery (MVS). Procedure related times and complexity of mitral valve surgery were retrospectively analysed after establishing this surgical technique.

Method: The first 300 patients operated at our center through an endoscopically enhanced MVS using a right anterolateral mini-thoracotomy and femoral cannulation, were compared for the following: perioperative times, mitral valve pathologies and reconstructive techniques. The underlying mitral valve pathologies were: degenerative (n = 279, 93%), ischemic (n = 3, 1%), rheumatic (n = 12, 4%), endocarditis (n = 5, 1.7%). All patients suffered from severe mitral regurgitation (3.2 ± 0.5) with a maintained ejection fraction of 60.2 ± 8.5%.

Results: There were no early deaths in this cohort. The overall repair rate was 95.3%. When rheumatic pathologies were excluded, repair rate improved to 98.2%. Table 1 shows significant reduction of the operating, – the ECC and the cross clamp-time (analysed in groups of 100 patients), as well as an increase in the complexity of procedures performed e.g. implantation of neo-chordae to AML and PML.

Table 1: Overall Analysis of Improvement

	0 – 100 patients	B vs. D p value	101 – 200 patients	D vs. F p value	201 – 300 patients
OP time [min]	293 ± 56	p ≤0.01	234 ± 55	p = ns	232 ± 41
ECC time [min]	181 ± 40	p = 0.02	163 ± 46	p = ns	153 ± 27
AXC time [min]	114 ± 24	p = ns	108 ± 30	p = 0.04	97 ± 19
Annuloplasty	89	p = ns	96	p = ns	96
Leaflet resection post.	77	p = ns	81	p = ns	72
Cleft repair	2	p ≤0.01	18	p = ns	13
Alfieri plasty	2	p = 0.01	11	p = ns	7
Neo-chordae AML	2	p ≤0.01	16	p = 0.04	28
Neo-chordae PML	2	p = 0.03	14	p = ns	17

Conclusion: The learning curve for minimally invasive MVS shows an improvement with respect to the procedure related times and complexity of the reconstructive techniques.