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Published on: March 27, 2018
Patency When Grafted to Coronary Stenosis More Than 50% in LIMA-RA-Y Grafts
Alistair G Royse1, Anthony P Brennan2, Zulfayandi Pawanis3
1The University of Melbourne, Department of Surgery, Melbourne, Vic, Australia.
Insights
Composite arterial grafts, including the left internal mammary artery and radial artery (LIMA-RA-Y), show acceptable late patency when used for coronary arteries with over 50% stenosis. Higher stenosis levels predict better graft survival.
Area of Science:
- Cardiovascular Surgery
- Interventional Cardiology
- Vascular Biology
Background:
- Current coronary artery bypass grafting (CABG) practices involve grafting arterial conduits to more severely stenosed coronary arteries.
- The study investigates the patency of composite Y grafts using the left internal mammary artery and radial artery (LIMA-RA-Y).
- Routine practice at the time of the study was to graft coronary arteries with >50% stenosis.
Purpose of the Study:
- To evaluate the long-term patency rates of composite arterial grafts (LIMA-RA-Y).
- To determine the relationship between native coronary stenosis severity and arterial graft patency.
- To analyze patency across different coronary territories (LAD, circumflex, RCA).
Main Methods:
- Analysis of 76 postoperative angiograms from 346 patients who underwent LIMA-RA-Y grafting between 1996-1999.
- Assessment of 256 anastomoses, with 230 targeted at coronary arteries with >50% stenosis.
- Generalized linear mixed model (GLMM) used to identify predictors of graft patency, defining "string sign" as occlusion.
Main Results:
- Overall graft patency was 84.0% (214/256) at a mean follow-up of 5.8 years.
- For grafts to coronary arteries with >50% stenosis, patency was 88% (201/230).
- Patency varied by territory: LAD 94%, circumflex 90%, and RCA 74%. Higher preoperative stenosis significantly predicted higher patency (OR 1.83 per 10% increase, p<0.001).
Conclusions:
- Composite arterial grafts demonstrate acceptable late patency when utilized in coronary arteries with significant stenosis (>50%).
- Grafting to targets with greater native coronary stenosis is associated with improved long-term patency.
- The LIMA-RA-Y composite graft is a viable option for coronary revascularization.
Background:
Recent coronary surgery practice is to graft arterial conduits to more severely stenosed coronary targets than in the past. We aimed to investigate postoperative arterial graft patency with native coronary stenosis at the time of surgery, using the left internal mammary artery and radial artery (RA) as a composite Y graft (LIMA-RA-Y). In the study timeframe, it was routine clinical practice to graft coronary arteries with >50% stenosis.
Methods:
Of 464 patients previously reported 1996-1999, 346 who underwent LIMA-RA-Y at the Royal Melbourne Hospital, 76 had postoperative angiograms at the same institution. Each anastomosis was considered separately. For arterial grafts a "string sign" was analysed as being occluded. Predictor of patency was performed with a generalised linear mixed model (GLMM).
Results:
Seventy-six (76) patients had postoperative angiograms at 5.8±5.4 years (range 0.23-19.4; interquartile range 1.7-10.0) years postoperative; with age at operation 62.5±10.7 years and 3.4±0.8 grafts per patient, 82% were male. Of 256 anastomoses, 230 were to coronary targets >50% stenosis. Overall patency was 84.0% (214/256). For coronary stenosis >50%, patency was 88% (201/230) and varied by coronary territory left anterior descending (LAD) 94% (87/93), circumflex 90% (71/79) and right coronary artery (RCA) 74% (43/58). Interaction for coronary territory was significant (p=0.022). Higher preoperative coronary stenosis predicted higher patency; with odds ratio for improved patency of 1.83 (95% CI 1.51, 2.22), p<0.001 for each 10% increase in stenosis.
Conclusions:
Late patency of composite arterial grafts is acceptable when grafted to coronary arteries of greater than 50% stenosis.
