Use Of Bilateral Internal Mammary Arteries Research Articles

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<25 (22.2%), overweight or 25-BMI<30 (37.2%), and obese or BMI>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.

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%.

Contemporary outcomes of coronary artery bypass grafting in obese patients.

This study evaluated the impact of obesity on outcomes of coronary artery bypass grafting (CABG) with particular attention to cases using bilateral internal mammary arteries (BIMAs). Patients undergoing isolated CABG from 2011 to 2017 at a single institution were categorized by body mass index (BMI): 18.5 to 24.9 kg/m2 , 25.0 to 29.9 kg/m2 , 30.0 to 34.9 kg/m2 , and ≥35 kg/m2 , respectively. The primary outcomes were mortality and readmission. Subgroup analysis was performed on CABGs using BIMAs. Adjusted Cox model curves were used for survival analyses and cumulative incidence function for readmissions. A total of 4980 patients underwent CABG with BMIs of 18.5 to 24.9 kg/m2 (17.8%; n = 884), 25.0 to 29.9 kg/m2 (35.0%; n = 1745), 30.0 to 34.9 kg/m2 (27.5%; n = 1368), and ≥35 kg/m2 (19.7%; n = 983), respectively. Patients with BMI 18.5 to 24.9 kg/m2 had a higher overall Society of Thoracic Surgeons predicted risk of mortality. Adjusted survival was similar across BMI groups, and readmission risk was highest in those with a BMI of 18.5 to 24.9 kg/m2 (P = .01). Increasing BMI was associated with higher rates of postoperative deep sternal wound infection (DSWI). CABG was performed with BIMA in 820 (16%). In patients undergoing CABG with BIMA use, there were no differences in survival, readmissions, or DSWI rates between BMI groups. CABG, including with the use of BIMA, can be performed in obese patients without an increased risk of mortality or hospital readmission out to 5 years. Although rates of postoperative DSWI increase with increasing BMI, this finding did not appear to be magnified in patients with BIMA, although the sample size was limited in this subanalysis. These data support the notion that BIMA use should not be precluded in the obese.

Is the Use of BIMA in CABG Sub-Optimal? A Review of the Current Clinical and Economic Evidence Including Innovative Approaches to the Management of Mediastinitis.

Bilateral internal mammary artery (BIMA) in coronary artery bypass grafting (CABG) has traditionally been limited. This review looks at the recent outcome data on BIMA in CABG focusing on the management of risk factors for mediastinitis, one of the potential barriers for more extensive BIMA utilization. A combination of pre-, intra- and postoperative strategies are essential to reduce mediastinitis. Limited data indicate that the incidence of mediastinitis can be reduced using closed incision negative-pressure wound therapy as a part of these strategies with the possibility of offering patients best treatment options by extending BIMA to those with a higher risk of mediastinitis. Recent economic data imply that the technology may challenge the current low uptake of BIMA by reducing the short-term cost differentials between single internal mammary artery and BIMA. Given that most published randomized controlled trials and meta-analyses of observational long-term outcome data favor BIMA, if short-term complications of BIMA including mediastinitis can be controlled adequately, there may be opportunities for more extensive use of BIMA leading to improved long-term outcomes. An ongoing study looking at BIMA in high-risk patients may provide evidence to support the hypothesis that mediastinitis should not be a factor in limiting the use of BIMA in CABG.

Systematic bilateral internal mammary artery grafting: lessons learned from the CATHolic University EXtensive BIMA Grafting Study.

Despite claims of feasibility, to date no study has examined the effect of systematic bilateral internal mammary artery (BIMA) use in a large cohort of real-world unselected patients. The CATHolic University EXtensive BIMA Grafting Study (CATHEXIS) registry was designed to assess the feasibility and safety of systematic BIMA grafting. The CATHEXIS was a single-centre, prospective, observational, propensity-matched study. The study was supposed to include 2 arms of 500 patients each: a prospective arm and a retrospective arm. The prospective arm included almost all patients referred for coronary artery bypass grafting (CABG) at our institution after the start of the CATHEXIS with very few exceptions. BIMA would have been used in all these patients. The retrospective arm included patients submitted to CABG before the start of the CATHEXIS and propensity matched to the prospective group (average BIMA use 50%; the radial artery was extensively used). Safety analyses were scheduled after enrolment of 200, 300 and 400 BIMA patients. After the first 226 patients, the BIMA use percentage was 88.5% (200 of 226). In 178 (89%) patients, mammary arteries were used as Y graft. Postoperative mortality was 2%, and incidence of perioperative myocardial infarction, graft failure and sternal complications were 3.5%, 3% and 5.5%, respectively. No perioperative stroke occurred. The incidence of major adverse cardiac events (particularly graft failure and sternal complications) in the BIMA arm were significantly higher than those in the propensity-matched cohort; the study was stopped for safety. In a real world setting the systematic use of BIMA was associated with a higher incidence of perioperative adverse events (particularly sternal complications). Individualization of the revascularization strategy and use of alternative arterial conduits are probably preferable to systematic use of BIMA.

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.

Scoring system to guide decision making for the use of bilateral internal mammary arteries: The BIMA score

ObjectiveCurrently, surgeons are unable to estimate whether the survival benefit from bilateral internal mammary artery (BIMA) grafting outweighs the increased deep sternal infection (DSWI) risk in the individual cases. As a consequence BIMA grafting is still largely underutilized. We aimed to develop and validate a scoring system to predict the individual risk for DSWI and 10 year survival probability to guide surgeons in decision making process for the use of BIMA over single internal mammary artery (SIMA). MethodsFast backward elimination on predictors was performed using Lawless and Singhal method. BIMA score was reported as a partial nomogram that can be used to manually obtain predicted individual risk of DSWI and 10 year survival probability from the regression models. Bootstrapping validation of the regression models was performed. ResultsThe study population consisted of 5234 patients of which a total of 960 (18%) received BIMA and the remaining 4274 (82%) underwent conventional strategy using SIMA. A total of 119 patients experienced DSWI (2.3%). A total of 489 deaths were recorded after a median follow-up time of 5.68 years (interquartile range 2.7–8.8, range 0–12.1). BIMA grafting was found to have effect on both risk of DSWI and 10 year survival probability and was included into partial nomograms. Bootstrapping validation confirmed a good discriminative power of the models. ConclusionThe BIMA score provides an impartial assessment of the decision making process for clinicians to establish the optimum revascularization strategy for individual patients.

Wound infections after median sternotomy treated by VAC therapy, summary of results, and risk factor analysis.

The aim of this study is to summarize results and analyze risk factors for the development of wound infection in heart surgery patients after median sternotomy. In this retrospective analysis with assessment of multiple risk factors, we examined 143 patients with infection after median sternotomy treated with VAC therapy from total of 4,650 patients operated in our department from 2012 to 2015. Total of 143 patients developed significant SSI treated by VAC therapy following cardiac surgery. Of these, only 14 patients developed DSWI and one patient was diagnosed with suspected osteomyelitis. BMI, female gender, and use of BIMA proved to be statistically significant risk factors in our study (p < 0.001). The acuteness of operations did not have a statistically significant effect. However, it had a significant effect on the severity of infection (p < 0.01). The severity of infection proved to be a significant prognostic factor for patients' outcome (p < 0.01). In our study, BMI, female gender, and use of BIMA (bilateral internal mammary artery) in patients with DM were predictors for the development of SWI. The acuteness of operation did not have a statistically significant effect. However, it had a statistically significant effect on the severity of infection (Tab. 3, Ref. 30).

Invited Commentary

Invited Commentary

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.

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.

Audit of 37 cases of deep sternal wound infections (DSWIs) following 2418 coronary artery bypass graftings (CABGs)

The purpose of this paper is to study the incidence of deep sternal wound infections (DSWIs) after median sternotomy, its correlation to demographic data, diabetes mellitus (DM), choice of vessels used for coronary artery bypass grafting (CABG), microbiological wound status, and outcome of surgical management in terms of complete wound healing, postoperative stay, and mortality. A total of 2418 patients who underwent CABG through median sternotomy from January 2005 to December 2013 were included in the study. DSWI was found in 37 patients. Logistic regression, Fisher’s exact test, and chi-squared test were used to find association, and a p value of <0.05 was considered as significant. Incidence of DSWI in our study is 1.53 %. In the whole population, M: F ratio was 5:1. Commonest age group of DSWI was 61 to 70 years. Out of 2418 patients, 1035 patients were diabetic, of which 31 (3 %) developed DSWI (p value 0.001). Out of these, in 1034 patients, bilateral internal mammary arteries (BIMAs) were used and 30 (2.9 %) patients developed DSWI (p value 0.030). Postoperative stays were longer for patients with multiple organisms in their culture (p value 0.029). Pectoralis muscle flaps were done in 30 patients, omentum with pectoralis in 2 patients, and simple suturing in 1 patient. Median hospital stay after definitive wound closure was 8 days. Wound healing was achieved in 79 % patients at the end of 2 weeks. Mortality after definitive wound closure was 6.06 %. DM is independent risk factor for DSWI. Use of BIMA in patients with DM increases the risk of DSWI. Aggressive wound debridement and early closure is associated with low mortality and shorter hospital stay.

Comparing use of BIMA in a Y-graft configuration to BIMA with additional radial artery use during CABG: Two institutional study

Arterial grafting has been demonstrated to confer long-term survival advantages to patients undergoing Coronary Artery Bypass Grafting (CABG). Arterial revascularization may be achieved through the sole utilization of sequential Bilateral Internal Mammary Arteries (BIMA) in a Y-graft construct, or the use of BIMAs with additional radial arteries (RA).

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.

Impact of pump status and conduit choice in coronary artery bypass: A 15-year follow-up study in 1412 propensity-matched patients

Previous studies have demonstrated that bilateral internal mammary artery (BIMA) grafts lead to superior outcomes compared with single internal mammary artery grafts. This study examines whether cardiopulmonary bypass affects conduit-dependent outcomes of coronary artery bypass grafting (CABG) surgery. From 1994 to 2013, a total of 6666 patients underwent isolated CABG surgery at our institution. Of these procedures, 3548 (53.2%) were performed off pump. A BIMA-saphenous vein graft (SVG) was used in 1544, and 5122 had left internal mammary artery-SVGs. These 2 conduit groups differed significantly in baseline characteristics. Propensity matching based on 22 preoperative variables and using a nearest-neighbor matching algorithm was used to make balanced cohorts, resulting in 2 groups of 1006. To account for the influence of pump status on conduit selection, a second propensity score was developed for pump use. These cases were matched to create 4 patient cohorts of 353 patients each (a total of 1412), balanced for both conduit use and pump status. Late mortality was determined using the Social Security Death Index. No difference was found in survival between patients receiving BIMA-SVGs on or off pump (78.9% vs 79.1%). BIMA-SVGs outperformed the left internal mammary artery-SVGs regardless of whether the procedure was performed off pump (73.9%) or on pump (69.9%). This study demonstrates that the use of cardiopulmonary bypass does not significantly affect the long-term outcomes in these patients as long as full revascularization is achieved. In addition, these results are consistent with prior research showing that the use of BIMAs produces better outcomes than use of a single internal mammary artery when performing CABG.

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 versus single internal mammary coronary artery bypass grafting in Sweden from 1997-2008.

BackgroundPrior observational studies have suggested better outcomes in patients who receive bilateral internal mammary arteries (BIMA) during coronary artery bypass grafting (CABG) compared with patients who receive a single internal mammary artery (SIMA). The aim of this study was to analyze the association between BIMA use and long-term survival in patients who underwent primary isolated CABG.Methods and ResultsPatients who underwent primary isolated non-emergent CABG in Sweden between 1997 and 2008 were identified. The SWEDEHEART registry and other national Swedish registers were used to acquire information about patient characteristics and outcomes. Unadjusted and multivariable adjusted regression models were used to estimate the association between BIMA use and early mortality, long-term survival, and a composite of death from any cause or rehospitalization for myocardial infarction, heart failure, or stroke in the overall cohort and in a propensity score-matched cohort. The study population consisted of 49702 patients who underwent CABG with at least one internal mammary artery, and 559 (1%) of those had BIMA grafting. In the adjusted analyses, BIMA use was not associated with better survival compared with SIMA use in the overall cohort (hazard ratio (HR) for death: 1.16, 95% confidence interval (CI): 0.97 to 1.37) or in the matched cohort (HR: 1.04, 95% CI: 0.78 to 1.40). The results were similar for early mortality and the composite endpoint. Reoperation for sternal wound complications was more common among BIMA patients (odds ratio: 1.71, 95% CI: 1.01 to 2.88).ConclusionsBIMA grafting was performed infrequently and was not associated with better outcomes compared with SIMA grafting in patients undergoing non-emergent primary isolated CABG in Sweden during 1997–2008.

EComment. Two internal mammary artery grafts are better than one

We read with great interest the paper by Smith et al. regarding the long-term survival benefit of the usage of bilateral internal mammary artery (BIMA) grafts in coronary revascularization surgery [1]. They included in their results 13 follow-up studies published after 2001. However, we found one additional relevant article investigating the long-term outcomes associated with BIMA grafting compared with single internal mammary artery (SIMA) among diabetic patients [2]. We would like to take this opportunity to briefly extract the relevant information from the above-mentioned study and to add a short comment on this salient subject. Puskas et al. [2] conducted a retrospective cohort analysis by extracting data from the Society of Thoracic Surgeons database at a single referral academic centre. They included a total of 3527 coronary artery bypass grafting procedures (BIMA n = 812, SIMA n = 2715). After adjustment for differences between groups by the Cox model, BIMA grafting portended a 35% reduction in the hazard of long-term death at 8 years of follow-up (adjusted hazard ratio, 0.65; 95% CI, 0.48 to 0.88, P = 0.006). The authors concluded that the usage of BIMA grafting provides significant benefit in late survival compared with SIMA grafting in both diabetic and non-diabetic patients. BIMA grafting should be performed whenever patient risk factors and comorbidities allow an acceptable risk of deep sternal wound infection. As rightly outlined by the authors, all these studies are follow-up studies. However, only one randomized trial comparing these two techniques (ART Arterial Revascularization Trial) [3] is currently under way in Europe that can broaden our understanding. ART primary outcome is survival at 10 years; therefore the results should be available by 2018. Until that date the debate will continue. This uncertainty has been reflected in the rate of adoption of BIMA grafting, the rate of use of the technique varies from 4% in North America to 10% in Europe [4]. The major reasons for not using BIMA grafts are the lack of solid evidence of benefits and the increased rate of sternal wound infection, particularly in diabetics. Of note, in the SYNTAX study [5], BIMA grafting was used in a relatively higher percentage of 28% of patients. The more liberal use of BIMA in this trial entails a paradigm shift in grafting strategies worldwide.

Bilateral internal mammary arteries: evidence and technical considerations.

Bilateral internal mammary artery (BIMA) grafts are used for coronary revascularisation by only a minority of surgeons, despite a growing body of evidence suggesting improved survival when compared to use of only one internal mammary artery with additional saphenous vein grafts. Herein we review the evidence supporting revascularisation with BIMA and suggest reasons why the majority of surgeons use only one internal mammary artery. We discuss technical considerations, various graft combinations and the use of BIMA to facilitate anaortic off-pump coronary artery bypass (OPCAB).