Bilateral internal mammary artery Y construct with multiple sequential grafting improves survival compared to bilateral internal mammary artery with additional vein grafts: 10-year experience at 2 different institutions†.

OBJECTIVES: Utilization of bilateral internal mammary arteries (BIMAs) has been shown to improve long-term outcomes in patients undergoing coronary artery bypass grafting. To achieve complete revascularization, BIMAs may be used as either sole conduits for revascularization through a Y-graft configuration (BIMA-Y) or deployed with additional grafts used in conjunction with BIMAs. The purpose of this study was to compare the long-term outcomes of two institutions that predominantly used either the BIMA-Y configuration or BIMA plus additional grafts to achieve optimal revascularization. METHODS: From 1 January 2000 to 31 December 2010, 436 patients were revascularized using a non-sequential BIMA grafting at one institution (Group A), with veins being used for additional targets. At the second institution (Group B), 771 patients were revascularized using a BIMA-Y graft for all distal targets. Kaplan­Meier analysis was used to compare unadjusted survival between the groups. Cox proportional hazards regression modelling was used to provide an adjusted comparison of survival between the groups. RESULTS: There was no statistically significant difference between the average number of anastomotic sites used in Group A and Group B (A = 4.0 ± 0.7 vs B = 4.0 ± 0.7; P = 0.24). Group A did not have a significantly greater in-hospital mortality (0.7% vs 1.0% P = 0.39), stroke (0.5% vs 0.8% P = 0.40), deep sternal wound infection (0.0% vs 0.6% P = 0.11) or reoperation for bleeding (1.6% vs 0.6% P = 0.10) than Group B. Cox proportional hazards analyses demonstrated that at 14 years, Group B had a significantly improved survival compared to Group A (Group B = 88% vs Group A = 81%) with an overall reduction in mortality (adjusted hazard ratio 0.780, 95% confidence interval 0.448­0.849; P = 0.043). CONCLUSION: Utilization of the BIMA-Y configuration was associated with improved survival when compared to BIMA grafting with additional vein grafts. Further studies are necessary to evaluate the efficacy of BIMA-Y grafting against other means of providing complete arterial revascularization.

Propensity matched analysis of bilateral internal mammary artery versus single left internal mammary artery grafting at 17-year follow-up: validation of a contemporary surgical experience.

OBJECTIVES: Bilateral internal mammary arteries (BIMA) remains widely underutilized in coronary artery bypass grafting (CABG). Although prior research has demonstrated a long-term benefit of the use of BIMA over left internal mammary artery (LIMA)-only, validation of these results is lacking in a contemporary surgical experience. We compared complications and survival at 17-year follow-up in a large series of consecutive CABG patients from a single institution that underwent BIMA grafting with a propensity-matched group where LIMA only was used. METHODS: Propensity scores representing the estimated probabilities of patients receiving either BIMA or LIMA alone were developed based on 22 observed baseline covariates in a logistic regression model with procedure group as the dependent variable. The nearest-neighbour-matching algorithm with Greedy 5-1 Digit Matching was used to produce two patient cohorts of 928 patients each balanced for baseline factors. We compared 30-day morbidity and mortality, as well as long-term survival at 5-year intervals up to 17-year follow-up. RESULTS: In-hospital and 30-day mortality was 0.8% for the BIMA group and 1.1% for the LIMA-saphenous vein grafting (SVG). No significant difference was found in complications, mortality and/or length-of-stay between these two groups. Off-pump was done in 48.9% of BIMA cases and 51.3% of LIMA cases. Regardless of the types of grafts used, on-pump patients were more likely to have postoperative permanent strokes and longer postoperative lengths of stay. Use of the BIMA over LIMA-only had a statistically significant impact conferring a 10% survival advantage at 10-year and 18% at 15-year follow-up. The Kaplan-Meier survival curves comparing off-/on-pump BIMA and off-/on-pump LIMA-SVG patients demonstrated a 22% survival advantage for off-pump BIMA patients when compared with on-pump LIMA-SVG patients at 15-year follow-up. CONCLUSIONS: Perioperative complications do not increase with the use of BIMAs. Long-term survival is optimized with off-pump CABG and BIMA grafting. The low morbidity and mortality rates in this series are likely due to the continuous evolution of technology and the adoption of less invasive options for CABG patients. A more widespread use of BIMAs in CABG patients would continue to improve the overall excellent short- and long-term results of this operation.

Stroke-related mortality in coronary surgery is reduced by the off-pump approach.

BACKGROUND: Stroke remains an important complication after coronary artery bypass graft surgery (CABG). We sought to determine the frequency and death-related incidence of stroke after on-pump and off-pump CABG. METHODS: We analyzed 4,869 consecutive isolated CABG performed in our institution. Of these, 3,490 (71.7%) were off-pump and 1,379 (28.3%) were on-pump. Propensity matched samples of 1,379 off-pump and 1,379 on-pump were compared on clinical presentation and The Society of Thoracic Surgeons (STS) predicted scores for risk of postoperative mortality and stroke. Univariate analyses were used to compare the relationship of off-pump and on-pump groups to postoperative mortality and stroke. Multivariate logistic regression was used to determine the unique association between all variables and occurrence of mortality after stroke. RESULTS: No differences were found for sex, diabetes mellitus, history of renal failure, prior stroke, or timing of surgery. Postoperative mortality occurred in 75 patients (2.7%) and stroke in 47 (1.7%). The off-pump patients had a lower rate of stroke (1.0% versus 2.4%; p < 0.01) compared with on-pump patients. Mortality after stroke occurred in 14 patients, with a lower rate occurring in the off-pump group (14.3% versus 36.4%; p = 0.07). Multivariate analyses controlling for the effect of preoperative risk factors and STS mortality risk demonstrated that off-pump status was independently associated with an 84% decrease in the risk of death after stroke (adjusted odds ratio 0.157, 95% confidence interval: 0.035 to 0.711, p = 0.016). CONCLUSIONS: Off-pump CABG is associated with lower stroke rates and stroke-related mortality. It may be useful to consider off-pump CABG for patients who are at higher risk for postoperative stroke.