Accelerated atherosclerosis in saphenous vein bypass grafts: A spectrum of diffuse plaque instability

https://doi.org/10.1053/pcad.2002.123471Get rights and content

Abstract

Our understanding of plaque instability may be extended to vein graft atherosclerosis, which appears to represent the end of a continuum of plaque instability. Compared with plaque in native coronary arteries, vein graft atheroma is more diffuse and vulnerable to rupture, and the consequences of plaque rupture in vein grafts seem to be associated with almost certain thrombotic occlusion within 7 to 12 years after surgery. Copyright 2002, Elsevier Science (USA). All rights reserved.

Section snippets

Structure and function of saphenous veins and arteries

There are several structural and functional differences between veins and arteries, which explain the greater susceptibility of veins to ischemic injury, lipid deposition, and thrombosis, leading to atherosclerosis and plaque vulnerability (Table 1).

Arterial injury

Vascular injury has been clearly identified as the critical inciting event in atherogenesis (Fig 1).

. Patterns of vascular injury in arterial and saphenous vein graft (SVG) atherosclerosis. ○, normal endothelium ●, dysfunctional endothelium.

Fuster et al proposed a unifying “response to injury” hypothesis describing 3 types of vascular injury progressing from functional endothelial changes (type I injury) to superficial injury to the vessel wall (type II injury) to deep medial injury (type III

Natural history of coronary artery bypass grafts and relationship to unstable plaque

The composition, vulnerability, and thrombogenicity of individual plaques vary greatly and are unrelated to stenosis severity.26, 27, 28, 29 Unifocal and multifocal plaque instability is recognized in the native coronary circulation as relatively distinct events occurring amidst long periods of plaque stability.30 It seems likely that SVG atherosclerosis represents the end of a continuum of plaque instability, in which diffuse, persistent vulnerable plaque passes through cycles of repetitive

Coronary angiography

Contrast angiography is the technique most commonly used to assess atherosclerotic plaque, but nearly all contemporary data about plaque stability are in the native arterial circulation, rather than vein grafts. Angiography is used to evaluate patients with acute coronary syndromes or progressive symptoms and is more useful for correlating the angiographic findings with the known clinical syndrome, rather than for predicting plaque vulnerability in a large population at risk. Angiography can

Magnetic resonance imaging (MRI)

MRI is a useful technique for imaging without ionizing radiation, and it can be repeated sequentially to follow patients over time. At present, high-resolution multicontrast MRI holds the most promise for identifying vulnerable plaque, by evaluating the lipid, fibrous, calcium, and thrombus content of atherosclerotic plaque.71, 72, 73 Coronary MR angiography can also evaluate patency of coronary arteries and bypass grafts. Unlike other imaging techniques, MRI has the potential to image and

Prevention of early SVG occlusion

Reduction in the extent of type III injury leading to early SVG occlusion may be accomplished by improved techniques of vein handling and harvesting. The availability of new platelet receptor antagonists and antithrombin agents is theoretically attractive because of the important role of platelets and thrombosis, but these potent agents are impractical in the perioperative period because of bleeding. Several clinical studies demonstrated that antiplatelet agents improve SVG patency during the

Conclusion

Plaque instability leading to plaque rupture is clearly implicated in the pathogenesis of acute coronary syndromes. Using angiographic criteria in native coronary arteries, there appears to be a spectrum of plaque behavior, including “normal” vessel, single or multiple stable plaques, and unifocal and multifocal unstable plaques. The principles underlying our understanding of multifocal plaque instability may be extended to our understanding of vein graft atherosclerosis, which represents the

References (100)

  • HC Nguyen et al.

    Mammary artery versus saphenous vein grafts: Assessment of basic fibroblast growth factor receptors

    Ann Thorac Surg

    (1994)
  • JJ Barboriak et al.

    Scanning electron microscopic study of human veins and aorta-coronary artery vein grafts

    J Thorac Cardiovasc Surg

    (1976)
  • JJ Barboriak et al.

    Pathological changes in surgically removed aortocoronary vein grafts

    Ann Thorac Surg

    (1976)
  • JJ Barboriak et al.

    Pathologic findings in the aortocoronary vein grafts

    Atherosclerosis

    (1978)
  • JJ Barboriak et al.

    Atherosclerosis in aortocoronary vein grafts

    Lancet

    (1974)
  • TL Spray et al.

    Changes in saphenous vein used as aortocoronary bypass grafts

    Am Heart J

    (1977)
  • WH Kern et al.

    The intimal proliferation in aortic coronary saphenous vein grafts: Light and electron microscopic studies

    Am Heart J

    (1972)
  • JM Kalan et al.

    Morphologic findings in saphenous veins used as coronary arterial bypass conduits for longer than one year: Necropsy analysis of 53 patients, 123 saphenous veins, and 1865 five-millimeter segments of veins

    Am Heart J

    (1990)
  • ED Verrier et al.

    Endothelial cell injury in cardiovascular surgery

    Ann Thorac Surg

    (1996)
  • EM Boyle et al.

    Endothelial cell injury in cardiovascular surgery: Atherosclerosis

    Ann Thorac Surg

    (1997)
  • AE Walts et al.

    Thrombosed, ruptured atheromatous plaques in saphenous vein coronary artery bypass grafts: Ten years' experience

    Am Heart J

    (1987)
  • JL Cox et al.

    Stranger in a strange land: The pathogenesis of saphenous vein graft stenosis with emphasis on structural and functional differences between vein sand arteries

    Prog Cardiovasc Dis

    (1991)
  • MM Rabah et al.

    Unstable coronary ischemic syndromes caused by coronary-subclavian steal

    Am Heart J

    (1996)
  • BM Kaplan et al.

    Usefulness of adjunctive angioscopy and extraction atherectomy before stent implantation in high-risk aortocoronary saphenous vein grafts

    Am J Cardiol

    (1995)
  • BH Annex et al.

    Evaluation of thrombus removal by transluminal extraction coronary atherectomy by percutaneous coronary angioscopy

    Am J Cardiol

    (1994)
  • SG Ellis et al.

    Late myocardial ischemic events after saphenous vein graft intervention importance of initially “nonsignificant” vein graft lesions

    Am J Cardiol

    (1997)
  • JA Ambrose et al.

    Angiographic morphology and the pathogenesis of unstable angina pectoris

    J Am Coll Cardiol

    (1985)
  • SL Bridal et al.

    Parametric (integrated backscatter and attenuation) images constructed using backscattered radio frequency signals (25-56 MHz) from human aortae in vitro

    Ultrasound Med Biol

    (1997)
  • T Hiro et al.

    Angle dependence of intravascular ultrasound imaging and its feasibility in tissue characterization of human atherosclerotic tissue (in process citation)

    Am Heart J

    (1999)
  • S Feld et al.

    Comparison of angioscopy intra-vascular ultrasound imaging and quantitative coronary angiography in predicting clinical outcome after coronary intervention in high-risk patients

    J Am Coll Cardiol

    (1996)
  • JA Silva et al.

    Morphologic comparison of atherosclerotic lesions in native coronary arteries and saphenous vein graphs with intracoronary angioscopy in patients with unstable angina

    Am Hear J

    (1998)
  • L Chen et al.

    Angiographic features of vein grafts versus ungrafted coronary arteries in patients with unstable angina and previous bypass surgery

    J Am Coll Cardiol

    (1996)
  • GS Mintz et al.

    Determinants and correlates of target lesion calcium in coronary artery disease: A clinical, angiographic and intravascular ultrasound study

    J Am Coll Cardiol

    (1997)
  • H Kai et al.

    Peripheral blood levels of matrix metalloproteinases-2 and -9 are elevated in patients with acute coronary syndromes

    J Am Coll Cardiol

    (1998)
  • R Limet et al.

    Prevention of aortocoronary bypass graft occlusion

    J Thorac Cardiovasc Surg

    (1987)
  • EC Keeley et al.

    Long-Term clinical outcome and predictors of major adverse cardiac events after percutaneous interventions on saphenous vein grafts

    J Am Coll Cardiol

    (2001)
  • R Choussat et al.

    Long-term clinical outcome after endoluminal reconstruction of diffusely degenerated saphenous vein grafts with less-shortening wall stents

    J Am Coll Cardiol

    (2000)
  • JCA Fuchs et al.

    Lipid composition in venous arterial bypass grafts

    Surg Forum

    (1972)
  • RM Larson et al.

    Lipid biosynthesis in arteries, veins, and venous grafts

    Circulation

    (1974)
  • VJ Henderson et al.

    Biochemical (functional) adaptation of “arterialized” vein grafts

    Ann Surg

    (1986)
  • JG DeMey et al.

    Heterogenous behaviour of the canine arterial and venous wall: Importance of the endothelium

    Circ Res

    (1982)
  • PM Vanhoutte

    Endothelium-dependent contractions in arteries and veins

    Blood Vessels

    (1987)
  • CC Haudenschild et al.

    Endothelial regeneration. II Restitution of endothelial continuity

    Lab Invest

    (1979)
  • JA Fishman et al.

    Endothelial regeneration in the rat carotid artery and the significance of endothelial denudation in the pathogenesis of myointimal thickening

    Lab Invest

    (1975)
  • MA Reidy et al.

    Endothelial regeneration. III. Time course of intimal changes after small defined injury to rat aortic endothelium

    Lab Invest

    (1981)
  • HIP John et al.

    Syndromes of accelerated atherosclerosis: Role of vascular injury and smooth muscle cell proliferation

    J Am Coll Cardiol

    (1990)
  • SJ George et al.

    Surgical preparative injury and neointima formation increase MMP-9 expression and MMP-2 activation in human saphenous vein

    Cardiovasc Res

    (1997)
  • E Falk

    Advanced lesions and acute coronary syndromes: A pathologist's view

  • AM Henney et al.

    Localization of stromelysin gene expression in atherosclerotic plaques by in situ hybridization

    Proc Natl Acad Sci USA

    (1991)
  • ZS Galis et al.

    Increased expression of matrix metalloproteinases and matrix degrading activity in vulnerable regions of human atherosclerotic plaques

    J Clin Invest

    (1994)
  • Cited by (0)

    Address reprint requests to Robert D. Safian, MD, Director, Cardiac and Vascular Intervention, William Beaumont Hospital, Heart Center, 3rd Floor, 3601 West 13 Mile Road, Royal Oak MI 48073.

    View full text