Minimally-invasive aortic root replacement.

PURPOSE We retrospectively analyzed our early results with minimally invasive aortic root replacement. METHODS Between August 1996 and April 1999, our center performed 137 aortic root replacements. Thirty-seven (27%) were accomplished through a 5 to 8 cm minimally invasive upper hemi-sternotomy incision. All minimally invasive operations were elective. The mean age for this cohort was 46 +/- 12 yrs. Thirty one (84%) of the patients were male and 3 (8%) were reoperations. The average preoperative NYHA classification was 2.4 +/- 0.6 and ejection fraction (EF) was 58% +/- 12%. Valve pathology was congenitally bicuspid in 19 (51%), endocarditis (SBE ) in 5 (14%), calcific degeneration in 4 (11%), annuloaortic ectasia in 3 (8%), rheumatic in 2 (5%) and other etiologies in 4 (11%). Nine patients (24%) had associated ascending aortic or arch aneurysms. RESULTS The surgical techniques performed through mini-hemisternotomy consisted of 1) full root replacement in 31 (84%), 2) subcoronary replacement in 4 (11%), and 3) hemiroot in 2 (5%). Valve implants consisted of a homograft in 30 (81%), "Freestyle" bioprosthesis in 4 (11%) and a St Jude valved conduit in 3 (8%). Mean cardiopulmonary bypass duration was 193 +/- 47 min. and aortic cross-clamp duration was 157 +/- 40 min. Myocardial protection included systemic hypothermia in all (24 +/- 4 degrees C), antegrade cardioplegia (CP) in 35 (95%) with supplemental retrograde CP in 23 (62%). Three patients (8%) experienced postoperative low cardiac output syndrome (LCO). There was one operative death (3%). There was one (3%) reoperation for bleeding and 13 patients (35%) required blood transfusions. New onset atrial fibrillation occurred in 7 patients (19%) and there were 3 (8%) minor complications. Hospital length of stay (LOS) was 6.7 +/- 4.3 days and LOS was less than 7 days in 29 patients (78%). CONCLUSIONS Minimally invasive aortic root replacement is feasible for a broad range of aortic valve pathology, can incorporate full root, hemiroot and subcoronary techniques, can be used for homografts and "Freestyle" valves as well as valved conduits, and can be accomplished with acceptable morbidity and mortality. However, the operation takes longer through the smaller incision and therefore requires more careful attention to myocardial protection.