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Angiographic evidence for reduced graft patency due to competitive flow in composite arterial T-grafts
Dmitry Pevni1, Itzhak Hertz, Benjamin Medalion
1Department of Cardiothoracic Surgery, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.
Insights
Composite T-grafting with bilateral internal thoracic arteries is best for severe coronary stenosis. Less severe blockages may lead to graft failure due to competitive flow, necessitating reintervention.
Area of Science:
- Cardiovascular Surgery
- Interventional Cardiology
- Vascular Biology
Background:
- Bilateral internal thoracic artery (BITA) grafting is a common technique.
- Composite T-grafting is one method for BITA.
- Flow distribution in BITA grafts can be affected by native coronary artery stenosis.
Purpose of the Study:
- To evaluate the outcomes of composite T-grafting with BITA.
- To identify factors influencing graft patency and failure.
- To determine optimal patient selection for this technique.
Main Methods:
- Analysis of 203 postoperative coronary angiographies from 163 patients undergoing BITA composite-T-grafting.
- Comparison of postoperative angiograms with preoperative studies.
- Assessment of graft patency and correlation with native coronary artery stenosis severity.
Main Results:
- 123 patients had patent BITAs; 40 had at least one non-functioning graft.
- Lower stenosis in the left anterior descending or circumflex arteries correlated with higher occlusion rates of the respective internal thoracic artery.
- Competitive flow was implicated in 19 cases, particularly with moderate stenosis (50-80%) in the left main, circumflex, or left anterior descending arteries.
Conclusions:
- Composite T-grafting with BITA should be reserved for patients with severe stenosis (≥70%) in the left anterior descending and circumflex arteries.
- This approach may reduce the risk of graft failure due to competitive flow.
- Careful patient selection is crucial for optimizing outcomes with this technique.
Objective:
Composite arterial grafting causes splitting of internal thoracic artery flow to various myocardial regions. The amount of flow supplying each region depends on the severity of coronary stenosis. Competitive flow in the native coronary artery can cause occlusion or severe narrowing of the internal thoracic artery supplying this coronary vessel.
Methods:
Two hundred three consecutive postoperative coronary angiographies of 163 patients who underwent bilateral internal thoracic artery grafting using the composite-T-graft technique were analyzed. Angiographies were done in symptomatic patients or in patients with positive thallium scan between 2 and 102 months after surgery and were compared with preoperative angiograms.
Results:
In 123 patients, both internal thoracic arteries were patent. The remaining 40 control patients had at least 1 nonfunctioning internal thoracic artery. A lower stenosis rate in the left anterior and circumflex arteries was associated with higher occlusion rate of the left internal thoracic artery (P < .005) and the right internal thoracic artery (P < .005), respectively. In 19 angiograms of 18 patients, graft failure could be related to competitive flow. This included 7 patients with disease of the left main artery and a preoperative stenosis degree ranging between 50% and 80%, 8 patients with moderate stenosis (70% or less) of the circumflex artery, and 3 with moderate stenosis of the left anterior descending artery. Three of the patients with disease of the left main artery, 2 of the patients with competitive flow in the circumflex artery, and all patients in the subgroup with left anterior descending arterial disease underwent percutaneous or surgical reintervention.
Conclusion:
The composite T-graft technique of bilateral internal thoracic artery grafting should be reserved for patients with severe (70% or more) left anterior descending and circumflex arterial stenosis.
