Original article
Adult cardiac
Angiographic Outcome of Coronary Artery Bypass Grafts: The Radial Artery Database International Alliance

Presented at the Fifty-fifth Annual Meeting of The Society of Thoracic Surgeons, San Diego, CA, Jan 26-29, 2019.
https://doi.org/10.1016/j.athoracsur.2019.07.010Get rights and content

Background

We used a large patient-level data set including 6 angiographic randomized controlled trials (RCTs) on coronary artery bypass conduits to explore incidence and determinants of coronary graft failure.

Methods

Patient-level angiographic data of 6 RCTs comparing long-term outcomes of the radial artery and other conduits were joined. Primary outcome was graft occlusion at maximum follow-up. The analysis was divided as (1) left anterior descending coronary (LAD) distribution and (2) non-LAD distribution (circumflex and right coronary artery). Mixed-model multivariable Cox regression including all baseline characteristics with stratification by individual trials was used to identify predictors of graft occlusion.

Results

Included were 1091 patients and 2281 grafts, consisting of 921 left internal mammary arteries, 74 right internal mammary arteries, 710 radial arteries, and 576 saphenous veins. All left internal mammary arteries were used on the LAD, the other conduits were used on the non-LAD distribution. Mean angiographic follow up was 65 ± 29 months. Occlusion rates were 2.3% for the left internal mammary arteries, 13.5% for the left internal mammary arteries, 9.4% for the right internal mammary arteries, and 17.5% for the saphenous veins. At multivariable analysis, type of conduit used, age, female sex, left ventricular ejection fraction of less than 0.50, and use of the Y graft were significantly associated with graft occlusion in the non-LAD distribution.

Conclusions

Our analyses showed that failure of the left internal mammary arteries-to-LAD bypass is a very uncommon event. For the non-LAD distribution, the nonuse of radial artery, age, female sex, left ventricular ejection fraction of less than 0.50, and use of the Y graft configuration were significantly associated with midterm graft failure.

Section snippets

Data Set

Details of the Radial Artery Database International Alliance (RADIAL) project have previously been published.2 The list of the RADIAL investigators is provided in Supplemental Table 1. Briefly, RADIAL is a patient-level database pooling 6 RCTs comparing the long-term outcomes of the radial artery (RAD) and other conduits at a mean follow up of 2 or more years. The 6 RCTs included are the Radial Artery Patency and Clinical Outcomes (RAPCO, groups 1 and 2), the Radial Artery Patency Study (RAPS),

Results

The angiographic analysis included 1091 patients and 2281 grafts, representing 71.8% of the total number of the patients enrolled in the 5 RCTs (1091 of 1519). The mean age was 64.9 ± 9.5 years, there were 825 men (75.6%), 329 patients (30.2%) were diabetic, 349 (32.0%) had previous MI, and 170 (15.6%) had an LVEF of less than 0.50. The mean number of grafts per patient was 3.4 ± 0.7. Demographics of the study population are reported in Table 1.

There were 921 left internal mammary arteries

Comment

With 1091 patients and 2281 grafts at a mean follow-up of 65 ± 29 months and a repeat angiography rate of almost 72%, RADIAL is one of the largest and the most complete coronary graft angiographic databases. The results of our analysis show that the failure of the LIMA-to-LAD bypass is a very uncommon event, so that even with a large patient sample, it was not possible to define independent risk factors for it. For the non-LAD distribution, the nonuse of the RAD, age 75 years or older, female

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A complete list of investigators of the RADIAL (Radial Artery Database International ALliance) project is provided in the Supplemental Material.

Drs Gaudino and Benedetto contributed equally to this work.

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