Bilateral Internal Mammary Artery Group Research Articles

Utilization of Vein Grafts in Coronary Artery Bypass Grafting: Reasons and Outcomes in a Bilateral Mammary Artery First Center

Objectives. Despite guideline recommendations for use of bilateral internal mammary artery (BIMA) in coronary artery bypass grafting (CABG), a large proportion of patients still receive saphenous vein grafts (SVG). We herein aimed to identify reasons for SVG use at a center with a BIMA utilization rate between 60 and 70% and compare outcomes of patients undergoing CABG with either BIMA or left internal mammary artery (LIMA) plus SVG. Methods. Between 2013 and 2022, 4145 consecutive patients underwent isolated CABG at our center. Of those, 2067 patients received BIMA (group 1) and 1206 patients received LIMA/SVG (group 2). A propensity score-matched analysis was performed to adjust for baseline differences. Results. Group 2 presented with higher age, more female patients, and more patients with acute coronary syndrome including NSTEMI/STEMI with more urgent/emergency CABG. In unadjusted analysis group 2 presented adverse 30-day outcomes compared to group 1 with a higher mortality (18/2067, 0.9% vs. 34/1206, 2.8%; p<0.001), higher rate of re-revascularization (52/2067, 2.5% vs. 50/1206, 4.1%; p<0.001), more stroke (20/2067; 1.0% vs. 33/1206, 2.7%; p<0.001), and more postoperative renal failure (17/2067, 0.8% vs. 27/1206, 2.2%; p=0.001). After adjustment for baseline characteristics, 30-day outcomes were comparable. Conclusions. After adjustment for baseline characteristics no differences in outcomes were found between groups suggesting a safe applicability of BIMA even in patients with acute coronary syndrome undergoing urgent/emergency CABG. Reasons for SVG use were higher age, female gender, and acute coronary syndrome with urgent/emergency CABG. Outcomes of both groups were excellent with low rates of primary endpoints.

Bilateral versus single internal mammary artery in diabetic patients: systematic review and meta-analysis.

Data on bilateral internal mammary artery (BIMA) versus single internal mammary artery (SIMA) on diabetics were analyzed; This is the only meta-analysis, the last 7 years. Medline through PubMed/EMBASE/CINHAL and the Cochrane Central Register of Controlled Trials; 179 articles were studied; 19 studies deemed suitable and were included in the analysis. The mortality was 2.41% for BIMA versus 1.71% for SIMA (odds ratio [OR] = 0.95; 95% confidence interval [CI]: 0.74-1.22). Postoperative reopening for bleeding was higher at 3.75% for BIMA versus 2.91% for SIMA (OR = 1.49; 95% CI: 1.15-1.93). The incidence of MI was 0.87% for BIMA versus 0.83% for SIMA (OR = 0.73; 95% CI: 0.37-1.44). Deep sternal wound infection was 3.02% for BIMA and 1.95% for SIMA (OR = 1.57; 95% CI: 1.26-1.95). When skeletonized, the incidence of DSWI was 2.5% for BIMA versus 2.41% for SIMA. There was a significant difference at 5-year survival favoring the BIMA, 85.15% BIMA versus 80.77% SIMA (OR = 1.79; 95% CI: 1.60-2.01). The 10-year overall survival was 74.04% BIMA versus 61.57% SIMA (OR = 1.79; 95% CI: 1.61-1.98). The 15-year survival was 47.08% for BIMA versus 37.06% for SIMA (OR = 1.69; 95% CI: 1.52-1.88). Postoperative bleeding was higher in BIMA group. Bilateral internal mammary artery in diabetic patients should be carried out in a skeletonize fashion, to reduce DSWI. There is a survival benefit of using BIMA in diabetics within 5 years of surgery; it remains significant up to 15 years.

Outcomes of Coronary Artery Bypass Grafting With Bilateral Internal Mammary Artery in Obese Patients

BackgroundThe purpose of this study was to evaluate postoperative outcomes with the use of bilateral internal mammary artery (BIMA) conduits in obese patients. MethodsBetween January 2003 and December 2018, 8109 patients underwent isolated coronary artery bypass grafting, including 7218 (89%) treated with single internal mammary artery (SIMA) and 891 (11%) treated with BIMA grafts. Patients were divided into 3 groups according to preoperative body mass index (BMI): normal, BMI <25 kg/m2 (22.2%); overweight, BMI of 25 to <30 kg/m2 (37.2%); and obese, BMI ≥30 kg/m2 (40.6%). In each group, BIMA and SIMA patients were compared to investigate 30-day mortality and postoperative complications. Significant baseline differences were observed between the 3 BMI groups, and such differences were adjusted by inverse probability weighting matching. ResultsThirty-day mortality, deep sternal wound infection (DSWI) rates, and length of hospital stay were 1.4%, 0.5%, and 6.0 ± 9.1 days for the normal group; 0.2%, 1.0%, and 5.5 ± 4.2 days for the overweight group; and 0.9%, 1.8%, and 5.5 ± 4.0 days for the obese group. There was no significant difference in 30-day mortality, incidence of DSWI, and hospital stay between BIMA and SIMA groups, except in the obese group, in which the rate of DSWI was significantly higher in the BIMA patients (3.4% vs 0%; P = .02). ConclusionsBIMA grafts in obese patients can be used without an increase of the 30-day mortality and hospital stay. However, the use of BIMA grafts in obese patients may lead to an increase of postoperative DSWI.

Abstract 13096: Outcomes After Coronary Artery Bypass Grafting With Bilateral Internal Mammary Arteries in Obese Patients

Introduction: The purpose of this study was to evaluate the postoperative outcomes with the use of bilateral internal mammary artery (BIMA) conduits in obese patients. Methods: Between January 2003 and December 2018, 8109 patients underwent isolated coronary artery bypass grafting (CABG) at our institution, including 7218 (89.0%) treated with single internal mammary artery (SIMA) and 891 (11.0%) treated with BIMA. Patients were divided into three groups according to preoperative body mass index (BMI), normal or BMI&lt;25 (22.2%), overweight or 25-BMI&lt;30 (37.2%), and obese or BMI&gt;30 (40.6%). In each group, BIMA and SIMA patients were compared to investigate the thirty-day mortality and postoperative complications. Significant baseline differences were observed between the three BMI groups and such differences were adjusted via inverse probability weighting matching. Results: The thirty-day mortality, deep sternal wound infection (DSWI) rates and length of hospital stay were 1.4%, 0.5%, and 6.0 ± 9.1 days for the normal group, 0.2%, 1.0% and 5.5 ± 4.2 days for overweight group and 0.9%, 1.8% and 5.5 ± 4.0 days for the obese group. There was no significant difference in the thirty-day mortality, incidence of DSWI and hospital stay between BIMA and SIMA groups, except in the obese group where the rate of DSWI was significantly higher in the BIMA patients (3.4 vs 0.0%, p=0.02). Conclusions: BIMA for isolated CABG in obese patients can be used without an increase of the thirty-day mortality and hospital stay. However, the use of BIMA in obese patients may lead to an increase of postoperative DSWI.

Left or bilateral internal mammary artery employment in coronary artery bypass grafting: midterm results.

The gold standard for coronary artery bypass grafting to the left anterior descending artery is use of the left internal mammary artery. Better long-term survival has been reported using bilateral internal mammary arteries compared to left internal mammary artery only, but many surgeons are reluctant to employ bilateral internal mammary arteries in coronary artery bypass grafting. This study aimed to evaluate the effectiveness and safety of bilateral internal mammary artery use. From 2014 to 2017, 1703 patients underwent coronary artery bypass grafting in our institute. Of these, 772 met the inclusion criteria and were randomly assigned to receive bilateral (n = 387) or left (n = 385) internal mammary artery grafts. The mean age was 67.1 ± 6.0 years (range 48-85 years) and 474 (61.4%) were male. The mean number of diseased vessels was 3.1 ± 0.9, and mean EuroSCORE II was 3.4% ± 1.1%. Hospital mortality was 1.2% in the left internal mammary artery group vs. 1.8% in the bilateral internal mammary artery group (p = 0.55). There was no difference in procedure-related complications between groups. Mean follow-up was 65.9 months. Survival in the bilateral internal mammary artery group at 1, 3, and 5 years was 98.7%, 98.7%, and 94.8% vs. 98.1%, 98.1%, and 90.9%, respectively, in the left internal mammary artery group (p = 0.63). Application of bilateral internal mammary arteries in coronary artery bypass grafting is safe and effective, with comparable midterm results to those with the left internal mammary artery only.

Wound complications and 30-day readmissions after single and bilateral internal mammary grafting: Analysis of the Nationwide Readmissions Database.

This study compares the postoperative outcomes, 30-day readmission rates, and incidence of sternal wound infection-related readmissions between patients receiving bilateral internal mammary arteries (BIMA) and single internal mammary artery (SIMA) grafting during coronary artery bypass graft (CABG) surgery. We utilized the weighted 2013-2014 National Readmission Database claims to identify all US adult patients who underwent CABG utilizing SIMA (n = 279,891) or BIMA (n = 11,651). Thirty-day overall and wound-related readmissions, in-hospital outcomes, costs, lengths of stay (LOS) at readmissions were compared between the two groups. Predictors of 30-day readmission were assessed using multivariable Cox proportional hazards analysis. After propensity matching (n = 10,339 pairs), there were no significant differences between the two groups during the index hospitalization, except for higher total hospital costs in the BIMA group (p = .02). The incidence of wound infections was also comparable between BIMA and SIMA (1.1% vs. 1.2%; p = .50). At 30-days, the overall readmission rate was elevated in SIMA patients (9.5% vs. 8.8%; p < .01), primarily impacted by cardiovascular causes. While the proportion of 30-day readmissions due to infections was significantly higher among BIMA versus SIMA patients (20.4% vs. 15.9%; p < .01), wound infections during the index hospitalization did not predict all-cause 30-day readmission among BIMA patients (p = .24) in the risk-adjusted analysis. Among the readmitted patients, LOS (6.4 vs. 6.2 days), costs ($14,440 vs. $16,461), and in-hospital mortality (2.4% vs. 1.7%) were comparable between the two groups (all p > .05). BIMA grafting is not an independent predictor of all-cause 30-day readmissions. Cardiovascular causes remain the primary driver of 30-day readmissions among SIMA and BIMA patients after CABG.

Short-Term Risk of Bilateral Internal Mammary Artery Grafting in Diabetic Patients

This study compares the morbidity and mortality at 30 days following the use of bilateral internal mammary arteries (BIMA) vs a single internal mammary artery (SIMA) at the time of coronary artery bypass grafting (CABG) in patients with a preoperative HbA1c. Patients undergoing CABG from January 2008 to December 2016 reported to the Society of Thoracic Surgeons database were retrospectively reviewed. The patients were divided into 2 groups: use of BIMA or use of SIMA and propensity matched. To assess the effect of preoperative HbA1c, both groups were further divided into 5 subgroups: patients without diabetes mellitus (DM), or patients with DM and a preoperative HbA1c level in one of four groups (< 7%, 7-9%, 9-11%, or >11%). The postoperative outcomes in both the BIMA and SIMA groups were compared. There were 700,504 and 28,115 patients with measured preoperative HbA1c levels in the SIMA and BIMA groups, respectively. Propensity score matching identified 23,635 comparable patients in each group for analysis. There was no difference in postoperative mortality between the BIMA and SIMA groups (1.3% vs 1.2%). The incidences of sternal wound infection (SWI) in patients undergoing placement of BIMA vs SIMA were: 0.8% vs 0.4% with no DM (P < 0.0001), 1.9% vs 1.0% with HbA1c < 7% (P < 0.001), 2.4% vs 1.2% with HbA1c 7-9% (P < 0.001), 2.8% vs 1.4% with HbA1c 9-11% (P = 0.02), 4.1% vs 1.5% with HbA1c > 11% (P = 0.01). Based on the incidence of SWI, BIMA is a reasonable approach with an HbA1c<7%.

Impacts of Skeletonized Bilateral Internal Mammary Artery Bypass Grafting on the Risk of Deep Sternal Wound Infection.

This single-center study aimed to evaluate the incidence of deep sternal wound infection (DSWI) following skeletonized bilateral internal mammary artery (BIMA) harvest in a Chinese cohort. Using propensity score matching, this study also provided a present-day assessment of the impacts of skeletonized BIMA grafting versus skeletonized single internal mammary artery (SIMA) grafting on early outcomes.From January 2014 to December 2017, 2403 eligible patients were entered into either a BIMA group (n = 368) or a SIMA group (n = 2035). The incidence of DSWI was recorded. Analysis of early outcomes was further performed for propensity score-matched (1:1) cohorts.The BIMA group received a similar incidence of DSWI as did the SIMA group (1.6% versus 0.9%, P = 0.247). No significant differences between subgroup diabetic-BIMA, subgroup nondiabetic-BIMA, subgroup diabetic-SIMA, and subgroup nondiabetic-SIMA were found regarding the incidence of DSWI (2.0%, 1.4%, 1.0%, and 0.7%, respectively; P > 0.05 between groups). After matching, treatment type (skeletonized BIMA grafting versus skeletonized SIMA grafting) was not an independent risk factor for postoperative DSWI (OR = 1.309, 95% CI 0.897-2.714, P = 0.704) or predictors of other early outcomes. Additionally, the two matched groups shared similar early outcomes (including postoperative DSWI), regardless of whether or not the merger with diabetes (all P > 0.05).Skeletonized BIMA harvest as compared with skeletonized SIMA harvest was not associated with an increased risk of DSWI, regardless of whether or not the merger with diabetes. Patients with skeletonized BIMA grafting received similar surgical mortality and major postoperative morbidity as did matched patients with skeletonized SIMA grafting.

Bilateral Versus Single Internal Mammary Artery Use in Coronary Artery Bypass Grafting: A Propensity Matched Analysis

Bilateral internal mammary artery (BIMA) grafts have demonstrated superior long-term outcomes compared with single internal mammary artery (SIMA) grafts. Despite this, BIMA remains widely underutilised due to perceived technical challenges and concerns regarding wound healing. We sought to examine the morbidity and mortality associated with BIMA use in a propensity-matched cohort of patients. From 2009 to 2016, 3,594 consecutive patients underwent coronary artery bypass surgery at three affiliated institutions. Thirty-day (30) mortality and morbidity data were collected prospectively. Propensity-score matched analyses were performed for BIMA versus SIMA use controlling for a number of preoperative characteristics. Overall, 29% of procedures were performed off pump, with a greater proportion in the BIMA group (43% vs. 21%, p<0.001). In the propensity-score analysis consisting of 820 matched pairs, there were similar rates of 30-day mortality (1.3% BIMA vs. 0.9% SIMA, p=0.48) and deep sternal wound infection (1.1% BIMA vs. 0.9% SIMA, p=0.84). The rate of superficial sternal wound infection trended towards being higher in the BIMA group (2.6% vs. 1.3%, p=0.077). The rates of red blood cell transfusions (27.4% vs. 27%, p=0.217), other blood product transfusions (18% vs. 20%, p=0.217), and reoperation for bleeding (2.9% vs. 2.1%, p=0.349) were similar. Bilateral internal mammary artery use was associated with similar rates of deep sternal wound infection compared to SIMA use, with a preponderance of superficial sternal wound infections that did not result in increased mortality or transfusion requirements. The use of BIMA should be more widely considered for coronary artery bypass surgery.

Bilateral Internal Mammary Artery Use Can Be Safely Taught Without Increasing Morbidity or Mortality

Evidence shows a likely survival benefit with the use of bilateral internal mammary arteries (BIMA) compared with a single internal mammary artery (SIMA). Nonetheless, BIMA use is often not used or taught because of a perceived increase in operative time and complexity. This study aimed to evaluate operative time, morbidity, and mortality in both resident and nonresident cases using BIMA compared with SIMA. Consecutive patients undergoing isolated coronary artery bypass grafting (October 2012 to April 2015) at a single institution were reviewed. Cases were stratified on the basis of the use of SIMA versus BIMA and resident teaching versus nonresident teaching cases. Primary outcomes included operative time, postoperative morbidity, and mortality. A total of 416 patients were identified; 335 of 416 (81%) patients received a SIMA, and 81 of 416 (19%) patients received BIMA. A total of 184 of 416 (44%) were resident cases: 143 of the 335 (43%) SIMA cases and 41 of the 81 (51%) BIMA cases. Use of BIMA in resident cases was associated with a longer operative and cardiopulmonary bypass (CPB) time than resident SIMA cases, but this increased time did not affect morbidity or mortality. Use of SIMA versus BIMA in nonresident cases had no significant difference on total operative time, CPB time, postoperative morbidity, or mortality. Overall, operative and 1-year mortality rates were similar in the SIMA and BIMA groups (SIMA: 1.2%, 1.8%, respectively; BIMA: 0%, 0%, respectively; p= NS). In the hands of an experienced surgeon, BIMA use can be effectively performed without an increase in operative or CPB time. In resident teaching cases, BIMA use may increase operative time, but it can be safely taught without affecting morbidity or mortality.

Bilateral vs unilateral internal mammary revascularization in patients with left ventricular dysfunction.

AIMTo investigate the survival benefit of bilateral internal mammary artery (BIMA) grafts in patients with left ventricular dysfunction.METHODSBetween 1996 and 2009, we performed elective, isolated, primary, multiple cardiac arterial bypass grafting in 430 consecutive patients with left ventricular ejection fraction ≤ 40%. The early and long-term results were compared between 167 patients undergoing BIMA grafting and 263 patients using left internal mammary artery (LIMA)-saphenous venous grafting (SVG).RESULTSThe mean age of the overall population was 60.1 ± 15 years. In-hospital mortality was not different between the two groups (7.8% vs 10.3%, P = 0.49). Early postoperative morbidity included myocardial infarction (4.2% vs 3.8%, P = 0.80), stroke (1.2% vs 3.8%, P = 0.14), and mediastinitis (5.3% vs 2.3%, P = 0.11). At 8-year follow-up, Kaplan-Meier-estimated survival (74.2% vs 58.9%, P = 0.02) and Kaplan-Meier-estimated event-free survival (all cause deaths, myocardial infarction, stroke, target vessel revascularization, heart failure) (61.7% and 41.1%, P < 0.01) were significantly higher in the BIMA group compared with the LIMA-SVG group in univariate analysis. The propensity score matching analysis confirmed that BIMA grafting is a safe revascularization procedure but there was no long term survival (P = 0.40) and event-free survival (P = 0.13) in comparison with LIMA-SVG use.CONCLUSIONOur longitudinal analysis suggests that BIMA grafting can be performed with acceptable perioperative mortality in patients with left ventricular dysfunction.

The Use of Bilateral Internal Mammary Arteries for Coronary Revascularization in Patients with COPD: Is It a Good Idea?

The use of bilateral internal mammary arteries (BIMA) is limited worldwide, especially in patients with chronic obstructive pulmonary disease (COPD). Thus, we assessed the safety of the use of BIMA in COPD patients. From cohorts of 8846 patients operated on at our center for primary isolated multi-vessel coronary bypass operations between 2002 and 2012, we studied two propensity-matched groups of patients with COPD who received either single internal mammary artery and saphenous vein grafts (SIMA group: 137 patients) or exclusively BIMA (BIMA group: 137 patients). Preoperative data were similar regarding age (63.59 ± 10.62 versus 65.55 ± 9.61 years; P = .10), body mass index (BMI) (28.6 ± 4.71 versus 28.42 ± 3.86 kg/m2; P = .72), diabetes mellitus (32% versus 27%; P = .08), EuroSCORE (4.34 ± 2.23 versus 4.8 ± 2.52; P = .09) and ejection fraction (58.7 ± 13.08% versus 60.29 ± 14.13%; P = .32). No significant differences were noticed between the two groups regarding the number of peripheral anastomoses (3.07 ± 0.77 versus 3.06 ± 0.85; P = .90), total operation time (192.17 ± 43.06 versus 200.63 ± 39.24 min; P = .08), postoperative stroke (0.7% versus 0%; P = .29), myocardial infarction (2.92% versus 3.6%; P = .81), reintubation (2.9% versus 4.4%; P = .66), reexploration (0.7% versus 2.2%; P = .32), deep sternal wound infection (2.9% versus 3.6%; P = .81) and 30-day mortality (2.2% versus 2.9%; P = .77). However, postoperative blood loss (726.1 ± 468.35 versus 907 ± 890.58 mL; P = .03) was higher in the BIMA group. COPD patients can benefit from coronary artery revascularization with BIMA; however, postoperative blood loss can be higher using this technique.

Bilateral mammary artery grafting increases postoperative mediastinitis without survival benefit in obese patients.

The prevalence of obesity has risen in the last decade, increasing the percentage of obese patients who undergo cardiac surgery. Deep sternal wound infection (DSWI) is a rare but devastating postoperative complication, more often encountered in the obese population. DSWI is also associated with the use of bilateral internal mammary artery (BIMA), particularly in this high-risk population. The aim of this study is to determine the short-term and long-term outcomes following BIMA revascularization in obese patients. This is a single-centre retrospective cohort study using prospectively collected data including all obese patients who underwent coronary artery bypass grafting (CABG) surgery between April 1991 and April 2014. Preoperative demographic characteristics, operative and postoperative variables were taken from the computerized database of the hospital. A propensity score matching was conducted for the short- and long-term outcomes in the entire study population. Results showed that 5608 patients with a body mass index of ≥30 kg/m2 underwent CABG during the studied period. After propensity scoring, 494 patients receiving BIMA were matched to 5089 patients receiving single internal mammary artery (SIMA). All preoperative characteristics were comparable except for a higher prevalence of left ventricular dysfunction and left main disease as well as higher mean EuroSCORE in the SIMA group. In the postoperative period, short-term mortality was comparable in the two groups (P = 0.68). In-hospital DSWI was also comparable (P = 0.10). However, when considering DSWI occurring after hospitalization (median time; 19 days), the latter was significantly lower in the SIMA than in the BIMA group (1.1 vs 3.2%; P < 0.0001). For long-term survival, no difference was observed between the BIMA and SIMA groups after appropriate matching (P = 0.22). In obese patients, CABG surgery using BIMA instead of SIMA increased the risk of postoperative DSWI, without improving survival. According to our results, short-term postoperative risks of infection associated with BIMA are not offset by longer-term benefits in that patient population. Special care should be exerted when selecting conduits for myocardial revascularization in obese patients.

Is Bilateral Internal Mammary Arterial Grafting Beneficial for Patients Aged 75 Years or Older?

Although bilateral internal mammary artery (BIMA) grafting is performed with increasing regularity in elderly patients, whether it is truly beneficial, and therefore indicated, in these patients remains uncertain. We retrospectively investigated early and late outcomes of BIMA grafting in patients aged ≥75 years. We identified 460 patients aged ≥75 years from among 2,618 patients who underwent either single internal mammary artery (SIMA) grafting (n=293) or BIMA grafting (n=107). Early outcomes did not differ between the SIMA and BIMA patients (30-day mortality: 1.7% vs. 0%, P=0.39; sternal wound infection: 1.0% vs. 4.7%; P=0.057). Late outcomes, 10-year survival in particular, were improved in the BIMA group (36.6% vs. 48.1%, P=0.033). In the analysis of the results in propensity score-matched groups (196 patients in the SIMA group, 98 patients in the BIMA group), improved 10-year survival was documented in the BIMA group (34.8% vs. 47.6%, P=0.030). Cox proportional regression analysis showed SIMA usage (non-use of BIMA) to be a predictor for late mortality (hazard ratio: 0.65, 95% confidence interval: 0.43-0.98, P=0.042). We further compared outcomes between the total non-elderly patients (n=2,158) and total elderly patients (n=460). BIMA usage was similar, as was 30-day mortality (1.0% vs. 1.3%, respectively). A survival advantage, with no increase in early mortality, can be expected from BIMA grafting in patients aged ≥75 years. (Circ J 2016; 80: 1756-1763).

Abstract 15732: Impact of Bilateral Mammary Artery Grafting for Coronary Revascularization in the Obese Population, a Retrospective Study

Context: The prevalence of obesity has increased over the last decade. Although bilateral internal mammary artery (BIMA) grafting for coronary revascularization is associated with better survival in the general population, it is also a risk factor for deep sternal wound infection (DSWI), a complication more frequently seen in the obese population. The aim of this study is to determine the short and long-term outcomes of the use of BIMA in obese patients undergoing cardiac surgery, assessing the impact on survival and the incidence of DSWI. Methodology: This is a single center retrospective cohort study with prospectively collected data. We included obese patients (BMI ≥ 30 kg/m2) undergoing coronary artery bypass grafting (CABG) between April 1991 and April 2014 in our institution. Propensity score matching was conducted for the entire population studied. Results: Results showed that 5608 obese patients underwent CABG during the study period. After propensity scoring, 494 patients receiving BIMA revascularization were matched to 5089 patients receiving single internal mammary artery (SIMA) revascularization. All pre-operative characteristics were comparable except for a higher prevalence of heart failure in the SIMA group. In-hospital post-operative mortality in the two groups was comparable (1.0% BIMA vs 1.8% SIMA, p=0.86). In-hospital DSWI was also comparable (1.2% BIMA vs 1.0% SIMA, p=0.63). However total DSWI (including post-discharge DSWI, median time 19 days) was significantly higher in the BIMA group compared to the SIMA group (3.6% vs 2.2%; p&lt;0.0001). Over a median follow-up of 7.2 years (mean follow-up 7.7 ± 4.2 years), there was no observed long-term survival advantage in the BIMA vs the SIMA group (p=0.22). Conclusion: Using BIMA instead of SIMA increases the risk of DSWI in obese patients. The use of BIMA is not associated with better survival compared to the use of SIMA in this population. These results suggest that the increased short-term risk of post-operative infection associated with BIMA revascularization is not offset by a long-term survival benefit. Given the increased risk of DSWI and absence of mid- to long-term survival benefit, caution should be exerted when selecting the use of BIMA grafting in the obese population.

Total Arterial Revascularization with Composite Y/T Grafts: Comparison of Early and Long-Term Outcomes of Bilateral Internal Mammary Arteries with Left Internal Mammary-Radial Artery Composite Grafts

Objectives: Coronary artery bypass graft surgery (CABG) utilizing total arterial revascularization (TAR) can be performed by constructing a composite Y/T-graft using either bilateral internal mammary arteries (BIMA) or the left internal mammary and radial arteries (LIMA-rad). The aim of our study was to compare the early and long-term clinical outcomes in patients, who received BIMAs with those who received LIMA-rad, both groups of patients being exclusively revascularized with the Y/T composite graft. Methods: A total of 504 patients underwent TAR solely with Y/T composite grafts at our institution from January 2001 through June 2010. Of these, BIMAs were used in 210 patients and LIMA-rad in 294 patients. Comparison of the 2 groups with regard to cumulative long-term mortality and major adverse cardiac and cerebrovascular events (MACCE) was performed using the competing risks method after matching for age, gender, number of diseased coronary arteries and presence of left main disease. The matched groups contained 186 patients each. Multivariate logistic regression analysis identified the significant predictors and the independent effect of the type of TAR (BIMA or LIMA-rad) on 30-day MACCE. Hazard ratios for late mortality and MACCE were estimated by Cox regression analysis. Results: The overall 30-day mortality amongst the matched groups was 1.6%, being 2.2% and 1.1% in the BIMA and LIMA-rad groups (p = 0.7), respectively. All-cause mortality (11·9% in BIMA group vs 12·4% in LIMA-rad group; p = 0·7) and acute myocardial infarction (1.1% vs 0.8%; p = 0·09) at 6 years were not significantly different between the matched groups. However, stroke rate was significantly higher in the BIMA group (5.8%) than in the LIMA-rad group (0.5%) (p = 0.007). Conversely, the rate of repeat revascularization was higher in patients with LIMA-rad (7.4%) than those with BIMA (4%), although it did not reach statistical significance (p = 0.16). Conclusions: TAR using BIMA or LIMA-rad in a Y/T configuration is associated with excellent early and long-term outcomes. Patients, who received BIMA, had a higher propensity of developing a stroke, but a lower repeat revascularization rate than those receiving LIMA-rad at follow-up.

Effects of on-pump and off-pump surgery in the Arterial Revascularization Trial.

The Arterial Revascularization Trial (ART) is a randomized comparison of bilateral internal mammary artery (BIMA) versus single internal mammary artery (SIMA) grafting in coronary artery bypass graft (CABG) surgery and is one of the largest randomized trials of surgery ever conducted. ART is also one of the largest studies of contemporary CABG with a high proportion of off-pump surgeries (41%). The objective of this post hoc analysis was to evaluate the surgical process and 1-year outcomes for surgery performed on-pump compared with off-pump. ART randomized 3102 patients with multivessel coronary artery disease (CAD) to SIMA or BIMA grafts to determine if BIMA grafts have an additional survival advantage at 10 years. The 1-year interim analysis showed an overall very low mortality and major morbidity rate irrespective of whether the procedure was with an SIMA or BIMA. The surgical process and 1-year outcomes were analysed according to whether surgery was performed on-pump or off-pump. Baseline variables were not statistically significantly different between on- and off-pump surgery within each treatment group after taking account of the effects of clustering by individual surgeons. At both 30 days and 1 year, there was a low incidence of death (1.2%, 2.3%), stroke (1.1%, 1.7%), myocardial infarction (MI) (1.4%, 1.9%), repeat revascularization (0.5%, 1.5%) and wound reconstruction (1.2%). A similar average number of grafts were performed with on- and off-pump surgery (median = 3), but the duration of surgery was 20-30 min and ventilation time ∼ 2 h shorter with off-pump surgery. Blood loss and platelet transfusions were lower in the off-pump group, with no difference in the need for balloon pump or renal support. Sternal wound reconstruction was similar with off-pump surgery in the SIMA group (0.5 vs 0.6%) and lower with off-pump surgery in the BIMA group (1.4 vs 2.2%). Repeat revascularization was marginally higher in off-pump patients at 30 days (0.8 vs 0.3%) and at 1 year (1.7 vs 1.3%). The outcomes of contemporary CABG are excellent with low mortality, stroke, myocardial infarction and need for wound reconstruction and repeat revascularization whether performed on-pump or off-pump. Controlled-trials.com (ISRCTN46552265).

The influence of bilateral internal mammary arteries on short- and long-term outcomes: A propensity score matching in accordance with current recommendations

We undertook a single-center, 12 years outcomes analysis of the influence of bilateral internal mammary arteries (BIMA) over single internal mammary artery (SIMA) on short-term outcomes and long-term outcomes by means of propensity score matching technique in accordance to current recommendations. A propensity score was generated for each patient from a multivariable logistic regression model based on 20 pretreatment covariates. The study population consisted of 4195 patients undergoing coronary artery bypass graft procedure using SIMA (n = 3445; 78.3%) or BIMA (n = 750; 21.7%). A total of 750 matching sets were derived. The BIMA group was associated with an increased rate of superficial sternal wound infection (5.6% vs 1.7%; P = .0001) but the incidence of deep sternal wound infection was comparable between the 2 groups, at 2.1% and 1.5% in BIMA and SIMA groups, respectively (P = .43). With regard to other postoperative complications the 2 groups were comparable. Operative mortality rate did not significantly differ between the 2 groups, at 0.7% and 1.2% in the BIMA and SIMA groups, respectively (P = .28). After a mean follow-up time of 4.8 ± 3.2 years, BIMA use was associated with a significantly lower risk for late mortality (hazard ratio, 0.61; 95% confidence interval 0.38-0.97; P = .03) and need for repeat revascularization (hazard ratio, 0.75; 95% confidence interval, 0.53-0.96; P = .03). When compared with SIMA grafting, BIMA use did not increase operative morbidity and mortality and was associated with a better long-term survival.

Effect of bilateral internal mammary artery grafts on long-term survival: a meta-analysis approach.

Although the potential survival benefit of bilateral internal mammary artery (BIMA) grafting in comparison with single internal mammary artery (SIMA) grafting has been emphasized by many investigators, the use of BIMA is still low in clinical practice in the absence of randomized trials and long-term results. In the current study, we aimed to assess if there is a long-term survival benefit of BIMA up to 10 years after coronary bypass surgery. We selected published articles comparing survival between SIMA and BIMA patients with follow-up duration of more than a mean of 9 years. We evaluated the log hazard ratio with 95% confidence interval for included studies by using a random-effects meta-analysis. Nine eligible observational studies provided 15 583 patients (8270 SIMA and 7313 BIMA) for meta-analysis. Five studies used propensity score methods for statistical adjustment, 2 with a propensity score-based patient-matching method and 3 with quintile-based stratification. A significant reduction in mortality by using BIMA was observed (hazard ratio, 0.79; 95% confidence interval, 0.75-0.84); no study showed any significantly harmful effect of BIMA on survival. Subgroups of studies using different statistical approaches-unmatched, quintile-based propensity score analysis, and propensity score-based exact patient matching-all showed the survival benefit of BIMA grafting. BIMA grafting appears to have better survival with up to 10 years follow-up in comparison with SIMA grafting. Long-term survival benefit of BIMA seems to continue in the second decade after surgery. An ongoing randomized trial comparing SIMA and BIMA groups will add evidence on this issue.

Bilateral internal mammary artery for multi-territory myocardial revascularization: long-term follow-up of pedicled versus skeletonized conduits.

The aim of this study was to evaluate 17-year actual clinical outcomes of patients undergoing coronary artery bypass graft (CABG) using skeletonized versus pedicled bilateral internal mammary arteries (BIMAs). From September 1991 to June 1996, 548 consecutive patients underwent CABG for multivessel disease using BIMA. After propensity matching, 350 patients were enrolled: 175 patients with skeletonized BIMA (Group S) and 175 with pedicled BIMA (Group P). The two groups were adequately comparable. Composite end-point: deaths, new revascularization and new myocardial infarctions were defined as 'events'. Group S provided a higher rate of total arterial myocardial revascularization (94.3 vs 82.9%, P 0.001) with a higher average number of arterial anastomoses (3.1 ± 0.8 vs 2.7 ± 0.8, P < 0.001) and BIMA anastomoses (2.5 ± 0.3 vs 2.1 ± 0.3, P < 0.001). In Group S, the incidence of sequential grafts was higher (37.7 vs 17.7%, P < 0.001). The rate of sternal wound healing problems was lower (1.7 vs 7.4%, P = 0.010). Thirty-day mortality and morbidity were similar. The median survival time of survivors was 17.8 years (min-max = 17.0-21.5); 17.3 (17.0-18.0) in Group S vs 19.1 (18.1-21.5) in Group P, P < 0.001. Seventeen-year actual outcomes were better in Group S: deaths (8.7 vs 27.9%, P < 0.001), cardiac deaths (4.7 vs 13.4%, P = 0.005), cardiac events (10.5 vs 22.1%, P = 0.003), new revascularization (2.9 vs 8.7%, P = 0.021) and events (15.1 vs 36.1%, P < 0.001). Skeletonization of BIMA allows one to achieve a higher rate of arterial grafting and better outcome if compared with pedicled BIMA.