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Extraluminal atherosclerosis: an under-recognised finding in human aortocoronary venous bypass grafts
Mihan Pourabdollah1, Seyed-Ahmad Hasssantash, Behnood Bikdeli
1Pediatric Respiratory Diseases Research Center, NRITLD, Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Insights
Extraluminal atherosclerosis was histopathologically identified in human vein grafts, a finding not previously reported. This study provides crucial evidence of this condition in aortocoronary vein grafts, impacting graft atherosclerosis research.
Area of Science:
- Cardiovascular Pathology
- Surgical Research
- Histopathology
Background:
- Graft atherosclerosis frequently compromises coronary artery bypass grafting (CABG) outcomes.
- While intraluminal atherosclerosis and positive remodeling are documented in native arteries, extraluminal atherosclerosis in vein grafts lacks histopathologic reports.
Purpose of the Study:
- To prospectively investigate the histopathologic presence and pattern of extraluminal atherosclerosis in human old vein grafts.
- To correlate histopathologic findings with clinical and angiographic data.
Main Methods:
- Prospective histopathologic examination of 100 segments from 20 human vein grafts during redo-CABG.
- Documentation of clinical and angiographic findings for each patient.
- Analysis of vessel wall thickness and plaque characteristics.
Main Results:
- Extraluminal atherosclerosis was detected in 7% of evaluated vein graft segments.
- Segments with extraluminal plaques showed significantly greater mean vessel wall thickness (1.41±0.26 mm vs. 0.91±0.04 mm, P=0.008).
- Angiographic findings moderately correlated with luminal atheromatous lesions but could not predict positively remodeled plaques.
Conclusions:
- This study presents the first histopathologic evidence of extraluminal atherosclerosis in human aortocoronary vein grafts.
- Findings suggest a potential new mechanism contributing to vein graft atherosclerosis and failure.
Background:
Coronary artery bypass grafting (CABG) is commonly compromised by graft atherosclerosis. Histopathologic studies confirm various forms of atherosclerosis, including positively remodelled lesions in native coronary arteries but there are no histopathologic reports of extraluminal atherosclerosis in vein grafts.
Methods:
We prospectively investigated the histopathologic presence and pattern of extraluminal atherosclerosis in human old vein grafts in a two-year interval among patients undergoing redo-CABG at three university hospitals in Tehran. We separately documented clinical and angiographic findings.
Results:
We evaluated 100 segments from 20 human old vein grafts obtained during the redo CABG. All but four segments demonstrated some degrees of luminal narrowing. Luminal atherosclerotic plaques were detectable in 61 segments. We detected extraluminal atheroscleoris in seven segments. Mean vessel wall thickness was greater in segments containing extraluminal plaques (1.41±0.26 mm versus 0.91±0.04 mm, P=0.008). Angiographic findings had a modest correlation with presence or absence of luminal atheromatous lesions (Spearman's rho: 0.331, P=0.007). Angiographic degree of stenosis could not predict the presence of positively remodelled atherosclerotic plaques (Spearman's rho: -2.21, P=0.073).
Conclusion:
Previous studies suggested positive remodelling in vein grafts. Out study provides histopathologic evidence on extraluminal atherosclerosis in human aortocoronary vein grafts.
