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Published on: May 14, 2013
Graft function, histopathology and morphometry of radial arteries used as conduits for myocardial revascularization
Stephen M Wildhirt1, Bernard Voss, Friederike von Canal
1Department of Cardiothoracic Surgery, German Heart Center Munich, Technical University of Munich, Lazarettstrasse 36, 80636 Munich, Germany. wildhirt@gmx.net
Insights
Radial artery grafts in older patients (70+) for coronary artery bypass grafting show minor to moderate atherosclerosis. Age and risk factors did not correlate with graft changes, suggesting age alone shouldn't exclude patients.
Area of Science:
- Cardiovascular Surgery
- Vascular Biology
- Geriatric Medicine
Background:
- Radial artery (RA) grafting is standard for younger coronary artery bypass grafting (CABG) patients.
- Advanced atherosclerosis may limit RA use in elderly patients.
- This study investigates age-related morphologic and histopathologic changes in RA grafts in patients aged 70+.
Purpose of the Study:
- To evaluate the impact of age on the morphologic and histopathologic characteristics of radial arteries used for coronary artery bypass grafting in patients aged 70 years and older.
- To assess graft quality through intraoperative angiography, flow measurements, and resistance index.
- To correlate age and traditional cardiovascular risk factors with the degree of atherosclerosis in radial artery grafts.
Main Methods:
- 31 patients (70-85 years) undergoing elective CABG received a radial artery graft to the second target vessel.
- Intraoperative assessment included Doppler flow, Allen's test, angiography, flow measurement, and resistance index (PI).
- Distal RA segments underwent histopathology and morphometry to quantify intimal and medial areas, intimal thickening index (ITI), intimal-medial ratio (IMR), and percentage of luminal narrowing (%LN).
Main Results:
- All radial artery grafts demonstrated satisfactory flow and resistance index, with no stenosis observed.
- Histopathology revealed minor to moderate atherosclerotic changes in all grafts, including intimal thickening and luminal narrowing.
- Neither patient age nor cardiovascular risk factors (diabetes, hypertension, smoking, hyperlipidemia) correlated with the degree of radial artery atherosclerosis.
Conclusions:
- Radial artery grafts in elderly patients (70+) yield excellent macroscopic and angiographic results.
- While minor to moderate atherosclerotic changes are present, they do not severely impair graft indices.
- Age should not be an absolute exclusion criterion for radial artery use in CABG, though caution is advised.
Background:
Coronary artery bypass grafting (CABG) using radial arteries has become a standard procedure for younger patients in many centers. However, advanced atherosclerotic changes may limit its use in older patients. We studied the effects of age on morphologic and histopathologic findings in CABG patients aged 70 years and older.
Methods:
In 31 consecutive patients aged 70-85 (mean 77+/-8 years) scheduled for elective CABG, the left or right radial artery (RA) was used to graft the second target vessel (first graft: LIMA-LAD). Preoperative Doppler flow and Allen's test were satisfactory. Intraoperatively the distal segment adjacent to the anastomosis site of the RA was collected for histologic evaluation. Intraoperative angiography, measurement of flow, and resistance index (PI) were performed to document graft quality. Histopathology and morphometry were used to measure intimal and medial areas (IA, MA; microm2), intimal thickening index (ITI), relation between intimal and medial width at maximum intimal thickness (IMR), and percentage of luminal narrowing (%LN).
Results:
The RA showed no evidence for stenosis of the conduits or the anastomosis. In all grafts flow and PI were satisfactory (76+/-14 ml/min; PI: 2.2+/-0.9). Histopathology and morphometry showed atherosclerotic changes in all RA grafts: IA: 890+/-971 (range 286-5244), MA: 2751+/-818 (range 1357-4989), ITI: 0.26+/-0.09 (range 0.12-0.44), IMR: 0.59+/-0.28 (range 0.21-1.13) %LN: 38+/-5 (range 13.2-61.7). Age as well as classic risk factors including diabetes, hypertension, smoking, and hyperlipidemia did not correlate with RA atherosclerosis.
Conclusions:
Excellent macroscopic and angiographic results were obtained. All grafts used showed minor to moderate atherosclerotic changes without severely altered indices of intimal thickening or luminal narrowing. The radial artery must be used with caution; however, age should not be an exclusion criterion per se.
