Aortic valve replacement by ministernotomy in redo patients with previous left internal mammary artery patent grafts

Aortic valve surgery with a patent left internal mammary artery (LIMA) on the left anterior descending (LAD) coronary artery is challenging in terms of myocardial protection and graft injury. Minimally invasive techniques may require minimal dissection of adhesions and may eventually decrease the risk of injuries.

Since 1997, more than 1000 ministernotomies have been performed by our surgical unit. Of these, 16 patients (14 males, 2 females, mean age: 68.7 years) had a patent LIMA graft on LAD. Fourteen underwent native aortic valve replacement, and in 2 a previously implanted prosthesis was replaced. A miniresternotomy was performed using either a "J" (15 patients) or a "reversed-T" method (1 patient).

Cardiopulmonary bypass (CPB) was achieved by either femoral vein (12 patients) or right atrium (4 patients); arterial inflow was achieved either by ascending aorta (12 patients) or by femoral artery (4 patients). Mean CPB time was 119.7 ± 38.1 minutes (range: 50-235). Mean cooling body temperature was 27.4 °C. Antegrade cold crystalloid cardioplegia was delivered to all the patients. Mean aortic cross-clamp time was 72 ± 20 minutes (range: 45-125). No damage to LIMA occurred in any of the patients. No intra- or perioperative myocardial infarction (MI) occurred. Neither a conversion to full sternotomy nor a reoperation for bleeding was needed. Mean postoperative bleeding was 426 ± 474 ml (range: 120-1950). A blood transfusion was necessary in 7 patients. Mean postoperative ICU stay was 1.6 ± 1.1 days. Mean postoperative hospital stay was 7.5 ± 2.6 days. Postoperative course was totally uneventful in 10 patients (58.8%). Follow-up was complete for a total of 928 patient/months (range: 11-124), and there were four late deaths, two of which were related to cardiac problems. Nine of the 12 survivors are in NYHA CLASS I . II. Prosthesis-related morbidity did not occur either early or late during follow-up.

This experience may represent the feasibility of an alternative surgical approach to a standard full-length median sternotomy in patients with previous coronary revascularization and with a patent LIMA on the LAD, requiring new surgery on the aortic valve.