Background: Angiotensin II is known to stimulate proliferation of fibroblasts and smooth muscle cells and enhance the atherosclerotic process in native coronary arteries. The impact of genetic polymorphisms of the renin-angiotensin-aldosterone system on coronary bypass graft degeneration is unknown.
Methods: We examined polymorphisms of four genes (AGTR1, CYP11B2, ACE, CMA) in 101 patients who had follow-up coronary angiography due to symptoms 88 +/- 52 months after coronary artery bypass graft surgery. Bypass degeneration was determined with quantitative coronary angiography and an adjusted Gensini score.
Results: Homozygosity for the G allele of the CMA-1905 polymorphism was associated with a higher degree of bypass degeneration (Bypass Gensini score CMA AA 21.4 +/- 39; AG 24.2 +/- 39.8; GG 27.8 +/- 42.3; NS-time adjusted Gensini bypass scores CMA AA 0.25 +/- 0.68; AG 0.57 +/- 1.82; GG 3.25 +/- 13.2; P = 0.005). No association could be detected for the AGTR1, CYP11B2 or ACE polymorphism.
Conclusion: The CMA allele G is a genetic risk factor for atherosclerosis in venous coronary artery bypass grafts. Its importance has to be shown in further studies. Other polymorphisms of the renin-angiotensin-aldosterone system do not seem to play a role in bypass degeneration.