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Updated: Apr 13, 2026

Establishment and Evaluation of a Porcine Vein Graft Disease Model
Published on: July 25, 2022
Pathology of internal mammary arteries used as bypass grafts
1Division of Anatomic Pathology, Cedars-Sinai Medical Center, Los Angeles, California, USA.
Insights
Internal mammary arteries used in coronary artery bypass grafts can develop arteritis or degenerative changes, potentially impacting graft patency and patient outcomes. These findings highlight the need for further investigation into the long-term health of these critical vascular conduits.
Area of Science:
- Cardiovascular Surgery
- Vascular Pathology
Background:
- Internal mammary arteries are frequently used as coronary artery bypass grafts.
- Long-term patency of these grafts is crucial for patient survival.
- Pathologic changes in grafts can compromise their function.
Purpose of the Study:
- To report pathologic findings in internal mammary artery grafts.
- To investigate potential causes of graft failure.
- To assess the risk of systemic vascular disease affecting these grafts.
Main Methods:
- Case series describing four patients.
- Pathologic examination of internal mammary artery grafts.
- Review of clinical data and surgical complications.
Main Results:
- Two grafts showed arteritis.
- Two grafts exhibited degenerative changes, including cystic medial necrosis.
- One case involved intraoperative dissection of the artery and aorta.
- Atherosclerosis was noted as a rare finding.
Conclusions:
- Internal mammary artery grafts can undergo significant pathologic changes.
- Arteritis and degenerative changes may compromise graft patency.
- Systemic vascular diseases, beyond atherosclerosis, can affect these grafts.
Abstract:
We describe four patients in whom internal mammary arteries used as coronary artery bypass grafts demonstrated pathologic changes that could affect long-term patency. Two grafts showed evidence of arteritis, and two showed degenerative changes as seen in so-called cystic medial necrosis. In one of these two cases intraoperative dissection of the internal mammary artery and aorta occurred. Aside from the rare occurrence of atherosclerosis, we have found no previous reports of systemic vascular disease affecting this artery.

