Radial artery grafting in women improves 15-year survival
Selected in Journal of Thoracic and Cardiovascular Surgery by S. Head
Dimitrova KR, Hoffman DM, Geller CM, Ko W, Lucido DL, Dincheva GR, Tranbaugh RF
J Thorac Cardiovasc Surg 2013;146:1467-1473
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It is believed that the use of arterial grafts for coronary artery bypass grafting (CABG) improves long-term survival when compared with the use of saphenous vein grafts (SVGs). Randomised trials have demonstrated improved graft patency with radial arteries, but have been unable to show improved survival due to a low sample size. Propensity-matched analysis did show that arterial grafting with either the right internal mammary artery of radial artery in addition to the standard use of the left internal mammary artery (LIMA) produced significantly better survival. However, studies focusing on the use of the radial artery are performed in populations with predominantly men while data in women remain scarce.
- Inclusion between 1995 and 2010, with 1339 female patients alive at 30 days after CABG of which 332 patients received a LIMA with a radial artery and 1007 a LIMA with a SVG.
- Endpoints: short-term operative complications and long-term survival up to 15 years.
- In the unmatched cohorts, women receiving a radial artery were younger, had a better left ventricular function, and more frequently had diabetes. After propensity matching which produced 283 pairs, only a prolonged cross-clamp and cardiopulmonary bypass time remained significantly different between groups, and was longer in patients receiving a radial artery.
- At 30-days, there were no differences in stroke, myocardial infarction, sternal wound infection, reoperation for bleeding, septicemia, or renal failure between patients receiving a radial artery or SVG in both unmatched and matched groups. However, patients receiving a SVG significantly more frequently angiography after CABG than patients receiving a radial artery, even in the propensity-matched groups (26.5% vs 18.4%, respectively; P=0.020).
- During long-term follow-up within the matched cohorts, 70 (25%) patients died in the SVG group while 48 (17%) in the radial artery group (P=0.023). Kaplan-Meier survival in the radial artery versus SVG group at one year (99% vs. 97%), 5 years (93% vs. 87%), 10 years (80% vs. 72%) and 15 years (70% vs. 58%) favoured those receiving a radial artery (P=0.018).
- In a propensity-score adjusted multivariate analysis of the entire cohort, the use of a radial artery remained an independent predictor of long-term mortality: hazard ratio 0.64, 95% CI 0.44-0.90; P=0.017)
The rate of using multiple arterial grafts in CABG remains disturbingly low, likely because no randomized trials have confirmed a superior survival benefit. Nevertheless, several studies have confirmed with the use of propensity-matched analysis that the use of bilateral internal mammary arteries of the radial artery produces a significantly improved long-term survival. The current study adds that the use of the radial artery provides excellent long-term results in women, better than with the use of vein grafts. This was not a randomized trial and therefore unmeasured confounding could still play a role, but the results from these and similar propensity-matched analyses are the best we currently have and need to be emphasized to convince surgeons that the use of multiple arterial grafts improves long-term results.