The Effect of Bilateral Internal Thoracic Artery Grafting on Survival During 20 Postoperative Years

doi:10.1016/j.athoracsur.2004.05.070

The Annals of Thoracic Surgery

Volume 78, Issue 6, December 2004, Pages 2005-2014

Presented at the Fortieth Annual Meeting of The Society of Thoracic Surgeons, San Antonio, TX, Jan 26–28, 2004.

https://doi.org/10.1016/j.athoracsur.2004.05.070 Get rights and content

Background

To compare survival of patients receiving bilateral internal thoracic artery grafts and single internal thoracic artery grafts more than 20 postoperative years, assess magnitude of benefit, and identify predictors of benefit.

Methods

From cohorts of 8123 patients receiving single internal thoracic artery grafts and 2001 receiving bilateral internal thoracic artery grafts during primary isolated bypass operations for multivessel coronary disease between 1971 and 1989, we identified 1152 propensity-matched pairs. Mean follow-up of survivors was 16.5 years, with 51 patients followed for 20 years or more. Hazard function methodology was used to identify risk factors for mortality, compare survival, and assess magnitude of benefit.

Results

Comparison of the matched pairs showed survival of the bilateral internal thoracic artery and single internal thoracic artery groups at 7, 10, 15, and 20 years was 89% versus 87%, 81% versus 78%, 67% versus 58%, and 50% versus 37%, respectively (p < 0.0001). Divergence of bilateral internal thoracic artery and single internal thoracic artery hazard function curves continued to widen through 20 postoperative years. At 20 years, bilateral internal thoracic artery grafting was predicted to produce worse survival in 2.8% of patients, a survival advantage of less than 5% in 12.9%, greater than 10% in 52%, and greater than 15% in 7.6%. Combinations of cardiac and noncardiac descriptors were used to define higher and lower risk patient subsets. Advanced age, abnormal left ventricular function and noncardiac risk factors decreased overall survival but the incremental benefit of bilateral internal thoracic artery grafting persisted.

Conclusions

Bilateral internal thoracic artery grafting produces improved survival compared with single internal thoracic artery grafting during the second postoperative decade, and the magnitude of that benefit increases through 20 postoperative years.

Section snippets

Patients and Methods

Patients from which the study sample is drawn came from 1000 patient-per-year cohorts of nonforeign, nonemergent patients undergoing primary isolated myocardial revascularization operations at the Cleveland Clinic Foundation during the years 1971 through 1989. These patients have been followed by questionnaire every 5 years. Of that group, 2001 patients underwent BITA grafting and 8123 had SITA grafting with or without accompanying vein grafts for treatment of multi-system coronary artery

Methods

Using the preoperative variables listed in Table 1, a propensity score was created to quantify the likelihood that a given patient would have received BITA grafts [5]. By matching propensity scores, 1142 BITA patients could be excellently pair-wise propensity matched to an SITA patient. The BITA patients who could not be matched were analyzed (Table 2) and were younger, taller, heavier, more likely to be male, and less likely to have abnormal left ventricular function, congestive heart failure,

Results

Overall survival of the BITA versus SITA groups (Fig 1) was 89% versus 87%, 81% versus 78%, 67% versus 58%, and 50% versus 37%, at 7, 10, 15, and 20 postoperative years, respectively (p < 0.0001). The death hazard function curves for both groups showed that the time-related risk of death continued to widen in favor of the BITA group through 20 postoperative years (Fig 2). Survival of unmatched BITA patients (75% at 15 years, Table 2) was superior to that of the matched BITA group (p < 0.001).

Comment

With time, survival of any group of patients decreases eventually to zero, and the rate of decrease is influenced by both cardiac and noncardiac factors. In this study we have tried to isolate the impact of BITA grafting on subsequent 20-year survival. If BITA grafting has a positive impact on survival, logic seems to dictate that it would be based on relief of myocardial ischemia, a decrease in frequency of major ischemic episodes, and perhaps improvement of left ventricular function for some

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Original ArticleCardiovascularThe Effect of Bilateral Internal Thoracic Artery Grafting on Survival During 20 Postoperative Years

Background

Methods

Results

Conclusions

Section snippets

Patients and Methods

Methods

Results

Comment

J Thorac Cardiovasc Surg

J Thorac Cardiovasc Surg

J Thorac Cardiovasc Surg

Ann Thorac Surg

Ann Thorac Surg

Bilateral internal thoracic artery grafting may improve outcome of coronary artery surgeryrisk-adjusted survival

Circulation

Benefit of bilateral internal mammary artery grafts over single IMA graft for multiple coronary artery bypass grafting

Circulation

Original Article
Cardiovascular
The Effect of Bilateral Internal Thoracic Artery Grafting on Survival During 20 Postoperative Years