Current indications for stentless aortic bioprostheses.

The best aortic prostheses have been debated for decades. The introduction of stentless aortic bioprostheses was aimed at improving hemodynamics and potentially the durability of aortic bioprostheses. Despite the good short- and long-term outcomes after implantation of stentless aortic bioprostheses, their use remains limited owing to the technically demanding implantation techniques. Nevertheless, stentless aortic bioprostheses might be of special benefit in certain indications, where they could be a valuable addition to the surgical armamentarium.

The Use of Bilateral Internal Mammary Artery Grafting in Different Degrees of Obesity.

Background Obesity is a limiting factor for the use of bilateral internal mammary arteries (BIMAs). Therefore, we assessed the safety of their use in different degrees of obesity. Patients and Methods We studied two groups of patients with obesity using propensity matching. The first group received single internal mammary artery and saphenous vein grafts (SIMA group, 526 patients) and the second group received bilateral internal mammary arteries (BIMA group, 526 patients). Patients were classified further according to their body mass index (BMI) into overweight (BMI = 25-29.9 kg/m2), obese (BMI = 30-34.9 kg/m2), and severely obese (BMI ≥ 35 kg/m2). Results Preoperative data were similar regarding age (62.78 ± 9.96 vs. 62.98 ± 9.66 years; p = 0.734), female sex (17.5 vs. 18.6%; p = 0.631), diabetes mellitus (26.3 vs. 27.2%; p = 0.74), EuroSCORE (3.21 ± 2.23 vs. 3.18 ± 2.41; p = 0.968), and COPD (16 vs. 16%; p = 1). No significant differences were noticed between the two groups regarding the number of peripheral anastomoses (3.09 ± 0.84 vs. 3.12 ± 0.83; p = 0.633), myocardial infarction (1.7 vs. 1.7%; p = 1), reexploration (1.3 vs. 2.1%; p = 0.34), deep sternal wound infection (DSWI) (2.1 vs. 2.9%; p = 0.43), and 30-day mortality (0.8 vs. 1.1%; p = 0.53). Multivariate analysis identified BMI and intensive care unit stay as independent predictors for DSWI. However, postoperative blood loss (694.56 ± 631.84 vs. 811.67 ± 688.73 mL; p < 0.001) and the incidence of pneumothorax (1 vs. 2.7%; p = 0.037) were higher in BIMA group. Conclusion Patients with obesity can benefit from BIMA grafting. However, postoperative blood loss and the incidence of pneumothorax can be higher using this technique.

Medtronic Freestyle aortic bioprosthesis: a potential option for haemodialysis patients†.

OBJECTIVES: End-stage renal disease patients on regular haemodialysis are at higher risk of calcification. Therefore, many surgeons have concerns regarding the implantation of bioprostheses in such patients. The haemodynamic advantages of stentless aortic bioprostheses support their use; however, these have not been studied yet in end-stage renal disease patients. We studied accordingly the early and mid-term outcomes of aortic valve replacement (AVR) using Medtronic Freestyle stentless aortic bioprostheses in this subset of patients in comparison with stented aortic bioprostheses. METHODS: We retrospectively studied two groups of consecutive patients on regular haemodialysis who required AVR between 2007 and 2013. Non-Freestyle (NFS) group received stented aortic bioprostheses (36 patients) and Freestyle (FS) group received Medtronic Freestyle aortic bioprostheses (48 patients). Follow-up ranged from 2 to 76 months with a mean follow-up of 36.3 ± 25 months. RESULTS: Patients in both groups showed similar demographic characters regarding age (76.4 ± 8.1 vs 74.9 ± 7.2 years; P = 0.35), male gender (58 vs 60%; P = 0.57) and diabetes mellitus (42 vs 48%; P = 0.57). Smaller aortic bioprostheses were implanted in the NFS (23.3 ± 1.2 vs 25.4 ± 2.1; P < 0.001) with consequently higher postoperative mean gradients (14.1 ± 4.1 vs 11.9 ± 5.3 mmHg; P = 0.004). No significant differences were noted regarding postoperative neurological disorder (8 vs 12%; P = 0.73), deep sternal wound infection (3 vs 4%; P = 0.68), re-exploration (8 vs 8%; P = 0.91) and in-hospital mortality (6 vs 4%; P = 0.92). Mid-term follow-up showed higher prosthetic valve calcification and/or sclerosis in NFS group (25 vs 6%; P = 0.015), whereas no significant differences were noticed between the two groups regarding stroke (0 vs 8%; P = 0.13), endocarditis (0 vs 4%; P = 0.50), 36- and 72-month survival (51 ± 2%, 14 ± 4% vs 55 ± 2%, 19 ± 3%, respectively; P = 0.45). CONCLUSIONS: Aortic bioprostheses are a good option for haemodialysis patients requiring AVR, offering acceptable mid-term survival. The Medtronic Freestyle aortic bioprostheses could allow the implantation of larger bioprostheses inferring consequently lower mean gradients, with a potentially higher resistance to calcification and sclerosis in haemodialysis patients.

Short term outcomes of total arterial coronary revascularization in patients above 65 years: a propensity score analysis.

BACKGROUND: Despite the advantages of bilateral mammary coronary revascularization, many surgeons are still restricting this technique to the young patients. The objective of this study is to demonstrate the safety and potential advantages of bilateral mammary coronary revascularization in patients older than 65 years. METHODS: Group I included 415 patients older than 65 years with exclusively bilateral mammary revascularization. Using a propensity score we selected 389 patients (group II) in whom coronary bypass operations were performed using the left internal mammary artery and the great saphenous vein. RESULTS: The incidence of postoperative stroke was higher in group II (1.5% vs. 0%, P = 0.0111). The amount of postoperative blood loss was higher in group I (908 +/- 757 ml vs. 800 +/- 713 ml, P = 0.0405). There were no other postoperative differences between both groups. CONCLUSION: Bilateral internal mammary artery revascularization can be safely performed in patients older than 65 years. T-graft configuration without aortic anastomosis is particularly beneficial in this age group since it avoids aortic manipulation, which is an important risk factor for postoperative stroke.

Concomitant aortic valve replacement and coronary bypass: the effect of valve type on the blood flow in bypass grafts.

OBJECTIVE: In cases of aortic valve replacement, the downstream flow profile and turbulence in the ascending aorta differ according to the prosthetic aortic valve implanted. The objective of this work is to study the influence of prosthetic valve type on the flow in the bypass grafts implanted to the ascending aorta in cases of concomitant aortic valve replacement and coronary artery bypass. METHODS: The study is conducted on 456 patients receiving concomitant aortic valve replacement and coronary bypass vein grafts anastomosed to the ascending aorta. The patients included in the study received a total number of 725 vein grafts, 249 biological aortic valves and 207 mechanical aortic valves. Intraoperative transit time flow measurement was done for all bypass grafts and a multiple regression model was calculated for the factors influencing the flow in the bypass grafts. RESULTS: The mean flow in vein grafts in patients receiving biological valves was 49.79+/-26.88 ml/min, while in patients receiving mechanical valves it was 46.54+/-26.68 ml/min. The multiple regression model revealed that receiving a mechanical valve is an independent risk factor for lower flow in the vein grafts. CONCLUSIONS: The type of the aortic valve implanted and consequently the downstream flow profile in the ascending aorta do affect the flow in the vein grafts in cases of concomitant aortic valve replacement and coronary bypass. Receiving a mechanical aortic valve is an independent risk factor for lower flow in the vein grafts.