David L. Galbut

Twelve-year experience with bilateral internal mammary artery grafts.

A 12 1/2-year experience with 227 patients who underwent coronary revascularization with bilateral internal mammary artery (IMA) and supplemental saphenous vein grafts is presented. There were 725 coronary grafts performed (3.2 per patient). Forty-four IMA grafts were sequential. In 42 patients, the right IMA was placed through the transverse sinus to revascularize the circumflex artery. Operative mortality was 4% (9 of 227 patients). Postoperative complications included sternal infection (4 patients), reexploration for bleeding (5), and diaphragmatic dysfunction (10). Postoperative arteriography in 30 patients (mean interval, 4 1/4 years) revealed that 92% (34/37) of the left IMA and 87% (26/30) of the right IMA grafts were patent. Late follow-up was complete in 207 surviving patients. Eighteen late deaths (9 cardiac and 9 noncardiac) occurred. Actuarial survival was 83% at 10 years after operation. Of 68 patients followed from 8 to 12 1/2 years (mean interval, 10 1/2 years), 69% were asymptomatic, and 28% were in New York Heart Association Functional Class II. We conclude that bilateral IMA grafting can be accomplished with low operative risk and provides excellent long-term results.

Thirty-Year Follow-Up Defines Survival Benefit for Second Internal Mammary Artery in Propensity-Matched Groups

BACKGROUND The value of the left internal mammary artery (LIMA) graft is well established. However, the incremental value of a second IMA graft is controversial. Despite reports of improved survival with bilateral IMA (BIMA) grafting, the Society of Thoracic Surgeons reports its use in 4% of coronary artery bypass graft operations. We report the influence of BIMA vs SIMA grafting on hospital and late mortality in comparable groups. METHODS Retrospective review was conducted of 4584 consecutive isolated coronary artery bypass graft operations (2369 SIMA and 2215 BIMA) performed from 1972 to 1994. The influence of the second IMA was assessed by multivariate analyses of risk factors associated with hospital and late mortality and by propensity score analysis that compares patients with similar baseline characteristics for receiving a second IMA graft. All patients were monitored clinically to assess outcomes. RESULTS Hospital mortality was 4.5% for SIMA vs 2.6% for BIMA patients (p = 0.001). When stratified by propensity score to undergo BIMA grafting, no difference in hospital mortality was found. Multivariate analyses showed SIMA grafting was significantly associated with late but not hospital mortality. Survival curves after 52,572 patient-years of follow-up (mean, 11.5 years; range, 6 weeks to 32 years) demonstrated improved long-term survival for BIMA vs SIMA patients in all quintiles except those with the greatest propensity for SIMA, wherein late survival was comparable between groups. In matched groups, survival favored BIMA patients (p = 0.001). CONCLUSIONS BIMA grafting offers a long-term survival advantage over SIMA grafting in propensity-matched groups.

Bilateral Internal Mammary Artery Grafting Enhances Survival in Diabetic Patients: A 30-Year Follow-Up of Propensity Score-Matched Cohorts

Background— The prevalence of diabetes mellitus is increasing at an unprecedented rate, affecting nearly 8% of the population. Previous studies have demonstrated a potential benefit for surgical over interventional revascularization in this group of patients. Similarly, studies have shown the superiority of bilateral internal mammary artery (BIMA) grafting over single internal mammary artery (SIMA) grafting in select populations. However, concerns about sternal wound infection have discouraged the use of BIMA grafting in diabetics. Therefore, we studied the long-term results of BIMA versus SIMA grafting in a large population of diabetic patients in whom BIMA grafting was broadly applied. Methods and Results— Between February 1972 and May 1994, 1107 consecutive diabetic patients underwent coronary artery bypass grafting with either SIMA (n=646) or BIMA (n=461) grafting. Optimal matching with the propensity score was used to create matched SIMA (n=414) and BIMA (n=414) cohorts. Cross-sectional follow-up (6 weeks to 30.1 years; mean, 8.9 years) determined long-term survival. There was no difference in operative mortality, sternal wound infection, or total complications between matched SIMA and BIMA groups (operative mortality, 10 of 414 [2.4%] versus 13 of 414 [3.1%]; P =0.279; sternal wound infection, 7 of 414 [1.7%] versus 13 of 414 [3.1%]; P =0.179); total complications, 71 of 414 [17.1%] versus 71 of 414 [17.1%]; P =1.000). Late survival was significantly enhanced with the use of BIMA grafting (median survival: SIMA, 9.8 years versus BIMA, 13.1 years; P =0.001). Use of BIMA was found to be associated with late survival on Cox regression ( P =0.003). Conclusion— Compared with SIMA grafting, BIMA grafting in propensity score–matched patients provides diabetics with enhanced survival without any increase in perioperative morbidity or mortality. # Clinical Perspective {#article-title-42}Background— The prevalence of diabetes mellitus is increasing at an unprecedented rate, affecting nearly 8% of the population. Previous studies have demonstrated a potential benefit for surgical over interventional revascularization in this group of patients. Similarly, studies have shown the superiority of bilateral internal mammary artery (BIMA) grafting over single internal mammary artery (SIMA) grafting in select populations. However, concerns about sternal wound infection have discouraged the use of BIMA grafting in diabetics. Therefore, we studied the long-term results of BIMA versus SIMA grafting in a large population of diabetic patients in whom BIMA grafting was broadly applied. Methods and Results— Between February 1972 and May 1994, 1107 consecutive diabetic patients underwent coronary artery bypass grafting with either SIMA (n=646) or BIMA (n=461) grafting. Optimal matching with the propensity score was used to create matched SIMA (n=414) and BIMA (n=414) cohorts. Cross-sectional follow-up (6 weeks to 30.1 years; mean, 8.9 years) determined long-term survival. There was no difference in operative mortality, sternal wound infection, or total complications between matched SIMA and BIMA groups (operative mortality, 10 of 414 [2.4%] versus 13 of 414 [3.1%]; P=0.279; sternal wound infection, 7 of 414 [1.7%] versus 13 of 414 [3.1%]; P=0.179); total complications, 71 of 414 [17.1%] versus 71 of 414 [17.1%]; P=1.000). Late survival was significantly enhanced with the use of BIMA grafting (median survival: SIMA, 9.8 years versus BIMA, 13.1 years; P=0.001). Use of BIMA was found to be associated with late survival on Cox regression (P=0.003). Conclusion— Compared with SIMA grafting, BIMA grafting in propensity score–matched patients provides diabetics with enhanced survival without any increase in perioperative morbidity or mortality.

Bilateral internal thoracic artery grafting improves long-term survival in patients with reduced ejection fraction: A propensity-matched study with 30-year follow-up

OBJECTIVE Bilateral internal thoracic artery (BITA) grafting has been shown to improve long-term survival after coronary artery bypass grafting. However, there has been reluctance to use this technique in higher-risk patients. Patients with reduced ejection fraction (EF) have been shown to present a higher operative risk and reduced long-term survival. We studied the perioperative and long-term results of BITA versus single internal thoracic artery grafting (SITA) in a large population of patients with reduced EF in whom BITA grafting was broadly applied. METHODS Between February 1972 and May 1994, 4537 consecutive patients in whom EF was recorded underwent SITA (2340) or BITA (2197) grafting. Prospectively collected clinical data recorded EF categorically as less than 0.30 (group I; n = 233), 0.30 to 0.50 (group II; n = 1256), or greater than 0.50 (group III; n = 3048). Multivariable analyses were performed to determine correlates of operative and late mortality. Optimal matching using propensity scoring was used to create matched SITA and BITA cohorts: group I, SITA and BITA, n = 87 each; group II, SITA and BITA, n = 448 each; group III, SITA and BITA, n = 1137 each. Equality of survival distribution was tested by the log-rank algorithm. RESULTS There was no difference in operative mortality between matched SITA and BITA groups (group I: SITA vs BITA, 10.3% vs 6.9%, P = .418; group II: 4.7% vs 4.5%, P = .873; group III: 3.2% vs 2.0%, P = .086). SITA versus BITA was not a predictor of operative mortality on logistic regression analysis. There was no difference in freedom from any postoperative complication, including sternal wound infection, between matched SITA and BITA groups. Late survival was significantly enhanced with the use of BITA grafting in groups II and III (10- and 20-year survival, SITA vs BITA, in group II: 57.7% ± 0.3% and 19% ± 2.5% vs 62.0% ± 2.3% and 33.1% ± 3.4%, respectively, P = .016; and in group III: 67.1% ± 1.4% and 35.8% ± 1.7% vs 74.6% ± 1.3% and 38.1% ± 2.1%, respectively, P = .012). Likewise, choice of SITA versus BITA was a significant predictor of late mortality on Cox regression in both groups II (P < .007) and III (P < .001). CONCLUSIONS Broadly applied BITA compared with SITA grafting in propensity-matched patients provides enhanced long-term survival with no increase in operative mortality or morbidity for patients with normal and reduced EF. The expanded use of BITA grafting should be seriously considered.

Coronary bypass surgery in women: a long-term comparative study of quality of life after bilateral internal mammary artery grafting in men and women.

BACKGROUND Coronary bypass surgery carries a higher operative mortality and less favorable long-term clinical benefits for women than men. The impact of arterial revascularization on long-term results, including quality of life (QOL) in women, compared with men, has not been clearly defined. METHODS A retrospective analysis was performed comparing 261 consecutive women patients from a single surgical practice receiving bilateral internal mammary artery (IMA) and supplemental vein grafts between January 1972 and October 1994 with a computer-matched cohort of 261 men undergoing bilateral IMA surgery during the same time period. Univariate analysis confirmed the homogeneity of the two groups based on multiple preoperative variables. The SF-36 QOL assessment tool was completed for all patients at follow-up, which ranged from 1 month to 25 years, with a mean follow-up of 9.1 years for women and 8.6 years for men. RESULTS There was no significant difference in operative mortality, nor in the incidence of any of 10 postoperative complications evaluated. The actuarial survival at 15 years was 53.7% +/- 4.8% for women and 50.9% +/- 5.6% for men (p = 0.218). At follow-up, 97.0% of women and 94.3% of men were free of angina and in Canadian Cardiovascular Society (CCS) class I or II. The need for reoperation (1.8% vs 1.9%) and PTCA (4.8% vs. 3.2%) was comparable in both groups. However, a higher rate of late myocardial infarction was found in women than men (1.8% vs 0.6, p = 0.021). The long-term event-free survival was found to be no different in men than women (p = 0.084). QOL as measured by the SF-36 was compared with the general population corrected for age and gender. Men and women scored as well or better than the general population in a majority of the eight health scales. Moreover, with regard to the health summary scores, men scored significantly higher (p = 0.001) in physical health, whereas women scored significantly higher (p = 0.011) in mental health when compared with age-adjusted norms. CONCLUSIONS Men and women undergoing coronary revascularization using bilateral internal mammary artery conduits experience comparable outcomes, excellent long-term results, and enjoy a QOL comparable to or better than the general population as measured by the SF-36.

Location of the second internal mammary artery graft does not influence outcome of coronary artery bypass grafting.

BACKGROUND Although the use of two internal mammary arteries (IMA) in coronary artery bypass graft surgery has been associated with improved patient survival and clinical status, the optimal use of the second IMA graft remains controversial. We, therefore, explored clinical outcomes in a large cohort of patients undergoing bilateral IMA grafting. METHODS Between February 1972 and May 1994, 2,215 consecutive patients underwent bilateral IMA grafting. The second IMA was used to revascularize the left coronary system (LCS) in 1,479 and the right coronary system (RCS) in 736 patients. Propensity score optimal matching algorithm was used to create the matched LCS group (n=730) and RCS group (n=730). Cross-sectional follow-up (6 weeks to 32.1 years; mean 12.8; 96.7% complete) was performed. Multivariable analyses were performed to determine correlates of operative mortality and late mortality. Patient clinical status and Short Form-36 scores of late survivors were compared. RESULTS There was no difference in either operative mortality or late survival between LCS and RCS patients, in either unmatched or matched groups. Operative mortality unmatched was LCS 38 of 1,479 (2.6%) versus RCS 20 of 736 (2.7%; p=0.837). For matched groups, it was LCS 13 of 730 (1.8%) versus RCS 20 of 736 (2.7%; p=0.284). Median survival in unmatched patients was LCS 15.8 years versus RCS 16.1 years (p=0.803); for matched patients, it was LCS 16.1 years versus RCS 16.1 years (p=0.671). Site of second IMA was not associated with either operative mortality or late survival on multivariable analysis. At follow-up, both groups demonstrated excellent clinical outcomes, with 98.4% of LCS patients and 96.8% of RCS patients in Canadian Cardiovascular Society class I or II, and no significant difference in either the physical (p=0.142) or mental (p=0.542) health summary scores on the Short Form-36. CONCLUSIONS Use of two IMA grafts demonstrates excellent long-term results with no demonstrable difference in outcome between RCS and LCS patients.

Bilateral internal mammary artery grafts in reoperative and primary coronary bypass surgery

Bilateral internal mammary artery grafting is recognized as a preferred method of myocardial revascularization. However, its efficacy in coronary bypass reoperation has not been clearly established. From January 1982 through June 1989, 88 patients underwent coronary bypass reoperation with bilateral internal mammary artery grafts. Results were compared with those for a subset of 88 patients receiving primary revascularization with bilateral internal mammary artery grafts who were computer matched for sex, age, left ventricular function, anginal classification, and left main coronary artery disease. In each group, 62.5% (55 patients) had unstable angina, 43.2% (38 patients) had reduced ejection fraction, and 21.6% (19 patients) in the reoperation group and 20.5% (18 patients) in the reference group had left main coronary artery disease. Hospital mortality for the reoperation group was 6.8% (6 patients) and for the reference group, 3.4% (3 patients). No significant difference was found in the incidence of reoperation for bleeding, sternal infection, or stroke in the two groups. The incidence of respiratory insufficiency in the reoperation group was 13.6% (12 patients) and in the reference group, 3.4% (3 patients) (p less than 0.015). Recurrent angina occurred in 13.7% (10 patients) of patients in the reoperation group and 13.3% (10 patients) in the reference group. The long-term survival at 5 years for the reoperation group was 85.3% +/- 5.6% (+/- standard error of the mean) and for the reference group, 91.6% +/- 3.1%. No significant difference was found in the equality of survival distribution for the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Bilateral internal mammary artery grafting in women: A 21-year experience

BACKGROUND Coronary artery bypass grafting traditionally has carried a higher mortality rate in women than in men. It remains the leading cause of death in women despite major advances in diagnosis and treatment over the past 2 decades. METHODS A retrospective analysis was conducted to identify risk factors that adversely influence hospital mortality, morbidity, and long-term clinical results in women undergoing bilateral internal mammary artery grafting. From January 1972 through October 1994, 327 consecutive women received bilateral internal mammary artery grafts and supplemental vein grafts. Patient age ranged from 32 to 84 years (mean, 65.7 years). There were 262 patients (80.1%) with three-vessel disease; 71 (21.7%) had substantial (> 50%) stenosis of the left main coronary artery, 65 (19.9%) had a moderately reduced (0.30 to 0.50) ejection fraction, and 11 (3.4%) had a severely reduced (< 0.30) ejection fraction. Preoperatively, 316 patients (96.6%) were in New York Heart Association class III or IV. RESULTS There were 1,016 coronary artery grafts (mean, 3.1 per patient). The overall hospital mortality rate was 3.4% (11 of 327). Postoperative complications included myocardial infarction in 18 patients (5.5%), stroke in 5 (1.5%), pulmonary insufficiency in 11 (3.4%), reoperation for bleeding in 7 (2.1%), and sternal infection in 8 (2.4%). Independent predictors of operative death were postoperative cardiac arrest (p < 0.001), use of intraaortic balloon pump (p < 0.001), and reoperation for bleeding (p < 0.050). Follow-up was completed on 316 hospital survivors (100%) and ranged from 6 months to 21 years (mean, 5.1 years). Actuarial survival (mean +/- standard error of the mean) was 90.5% +/- 1.9% at 5 years and 65.6% +/- 6.1% at 10 years. At follow-up, 252 patients (94.0%) were asymptomatic in New York Heart Association class I, and 12 (4.5%) were in class II. CONCLUSIONS This longitudinal study demonstrates that bilateral internal mammary artery grafting, though technically demanding, can be achieved in women with low hospital mortality and morbidity rates. Patients experienced reduced late cardiac events, excellent functional improvement, and enhanced long-term survival.

Bilateral internal mammary artery grafting reverses the negative influence of gender on outcomes of coronary artery bypass grafting surgery

OBJECTIVES Coronary artery bypass grafting (CABG) has historically demonstrated higher hospital mortality in women compared with men. The influence of gender on long-term outcomes has not been clearly defined. METHODS A retrospective analysis of 4584 consecutive CABG patients was conducted: 3647 men (1761 single internal mammary artery, [SIMA]; 1886 bilateral IMA, [BIMA]) and 937 women (608 SIMA and 329 BIMA). Propensity-score analysis and optimal matching algorithms were used to create matched groups for baseline risk factors between men and women (SIMA: 602 men and 602 women; BIMA: 328 men and 328 women). Cross-sectional follow-up (6 weeks to 32.1 years; mean 12.8 years) was 96.7% complete. RESULTS Hospital mortality was higher in unmatched female vs male patients (SIMA 36/608; 5.9 vs 72/1761; 4.1%; BIMA 11/329; 3.3 vs 47/1886; 2.5%; P = 0.010). However, in the matched groups the increased hospital mortality for females approached statistical significance in the SIMA but not in the BIMA patients. (SIMA male 21/602, 3.5%; female 35/602, 5.8%; P = 0.055; BIMA male 12/328; 3.7%; female 11/328; 3.4%; P = 0.832). When propensity matched for baseline variables, the female SIMA patients experienced prolonged survival compared with their male counterparts. (male vs female, 20-year survival 17.0 ± 2.0 vs 26.4 ± 2.3%; median 10.4 vs 11.4; P = 0.043.) However, long-term survival between the matched male and the female BIMA patients was comparable (male vs female, 20-year survival 31.3 ± 3.6 vs 30.1 ± 3.6%; median 13.7 vs 13.7; P = 0.790). CONCLUSIONS When liberally applied, BIMA grafting ameliorates both the increased perioperative mortality in female patients and the reduced long-term survival of male patients, effectively reversing the negative influence of gender on both short- and long-term outcomes of CABG surgery.

Efficacy of single versus bilateral internal mammary artery grafting in women: a long-term study

BACKGROUND Coronary artery bypass grafting carries a higher operative mortality and less favorable long-term benefit in women than in men. Bilateral internal mammary artery grafting (BIMA) has been shown to yield excellent perioperative and long-term results in both women and men. However, controversy continues to exist as to the benefits of a second internal mammary artery graft in women. METHODS A retrospective analysis was performed comparing 261 consecutive women from a single surgical practice receiving BIMA and supplemental vein grafts between January 1972 and October 1994 with a computer-matched cohort of 261 women receiving single internal mammary artery (SIMA) and vein grafts during the same period. Univariate analysis confirmed the homogeneity of the two groups based on nine preoperative variables. RESULTS Operative mortality was comparable in the two groups, 3.8% (10 of 261 patients) in the SIMA and 3.4% (9 of 261 patients) in the BIMA group, with a markedly reduced mortality in both groups since 1990, 2.3% (2 of 86 patients) in the SIMA and 1.3% (1 of 78 patients) in the BIMA group. The mean number of distal grafts (2.78, SIMA; 3.14, BIMA), perfusion time (104 minutes, SIMA; 108 minutes, BIMA), and cross-clamp time (58 minutes, SIMA; 66 minutes, BIMA) were all comparable. There was no significant difference in the incidence of postoperative complications, including sternal wound infection. Patient follow-up ranged from 1 month to 27 years, with a mean of 10.0 years in the SIMA group and 9.1 years in the BIMA group. Clinical results were excellent, with 100% (136 of 136 patients) of the SIMA and 100% (167 of 167 patients) of the BIMA patients in Canadian Cardiovascular Society class I or II at follow-up. Rates of late myocardial infarction, percutaneous transluminal coronary angioplasty, and reoperation were similarly low in both groups: 3.7% (5 of 136 patients) versus 1.8% (3 of 166 patients), 5.4% (7 of 136 patients) versus 4.8% (8 of 166 patients), and 3.7% (5 of 136 patients) versus 1.8% (3 of 166 patients), for SIMA versus BIMA survivors, respectively. No significant difference was found in the long-term and event-free survival or in any of the eight subscales of the SF-36 quality of life survey for the two groups. CONCLUSIONS Excellent short- and long-term results have been demonstrated with internal mammary artery grafting in women. However, the addition of a second internal mammary artery graft does not appear to confer any additional clinical benefits in a comparably matched cohort of patients.