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Thrombosed, ruptured atheromatous plaques in saphenous vein coronary artery bypass grafts: ten years' experience
A E Walts1, M C Fishbein, J M Matloff
1Division of Anatomic Pathology, Cedars-Sinai Medical Center, Los Angeles, CA 90048.
Insights
Saphenous vein grafts used in coronary artery bypass grafting (CABG) frequently occlude due to thrombosis on ruptured plaques. This common mechanism necessitates repeat procedures and can lead to adverse outcomes.
Area of Science:
- Cardiovascular Surgery
- Vascular Biology
- Pathology
Background:
- Coronary artery bypass grafting (CABG) using saphenous vein grafts has seen increased utilization globally.
- Late graft occlusion remains a significant concern, with an annual rate of approximately 4% and a rising incidence of reoperations.
- Reoperations for occluded grafts increased from 0.8% in 1976 to 12.4% by 1985 at the institution.
Purpose of the Study:
- To investigate the pathological mechanisms underlying late saphenous vein graft occlusion after CABG.
- To identify the prevalence and characteristics of the lesion causing graft failure.
- To determine the clinical significance and potential therapeutic targets for graft occlusion.
Main Methods:
- Analysis of 119 excised, occluded saphenous vein grafts from patients undergoing reoperation.
- Examination of 10 autopsy cases with occluded saphenous vein grafts.
- Histopathological assessment to identify the nature of the occlusive lesion.
Main Results:
- Thrombosis superimposed on ruptured atheromatous plaques was identified in 44% (52 of 119) of excised grafts.
- Similar lesions were observed in grafts from autopsy cases.
- The occlusive lesion occurred between 3 and 14 years post-CABG, with a peak incidence 5 to 10 years after implantation.
- Graft occlusion mechanism was independent of patient age, sex, or bypassed coronary artery.
Conclusions:
- Thrombosed, ruptured atheromatous plaque is a prevalent and clinically significant cause of late saphenous vein graft occlusion.
- This mechanism is associated with recurrent symptoms, repeat revascularization, and potential mortality.
- The identified lesion may be a target for interventions such as thrombolytic therapy or angioplasty.
Abstract:
During the past decade the number of patients undergoing saphenous vein coronary artery bypass grafting (CABG) has increased worldwide. With a rate of late graft occlusion approximating 4% each year, the number of patients at risk for late graft occlusion continues to increase. Whereas in 1976 only 0.8% of the CABGs performed at our institution were reoperations for occluded grafts, by 1985 repeat procedures comprised 12.4% of the CABGs performed. Excised, occluded saphenous vein grafts from 52 of 119 (44%) of these patients showed thrombosis superimposed on ruptured atheromatous plaques. Ten autopsy patients showed similar lesions in their occluded grafts. The lesion was present in grafts excised as early as 3 years and as late as 14 years after bypass surgery; most occurred 5 to 10 years after implantation. Neither age at first bypass, sex, nor coronary artery bypassed permitted prediction of the occurrence of the lesion. Thrombosed, ruptured atheromatous plaque is a common, clinically significant mechanism of late graft occlusion. It is associated with recurrent symptoms that necessitate repeat revascularization and may result in death. The lesion may also be amenable to thrombolytic therapy, angioplasty, or both.