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Collateral Blood Vessels

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Collateral Blood Vessels

Basics

Description

Coronary angiography reveals grades of collateral filling:

1Cohen M, Rentrop KP. Limitation of myocardial ischemia by collateral circulation during sudden controlled coronary artery occlusion in human subjects: a prospective study. Circulation. 1986;74:469-476. [View Abstract]2Fukai M, Ii M, Nakakoji T. Angiographically demonstrated coronary collaterals predict residual viable myocardium in patients with chronic myocardial infarction: a regional metabolic study. J Cardiol. 2000;35:103-111. [View Abstract]3Isner JM, Pieczek A, Schainfeld R. Clinical evidence of angiogenesis after arterial gene transfer of phVEGF165 in patients with ischemic limbs. Lancet. 1996;348:370-374. [View Abstract]4Kern M. Atherosclerotic cardiovascular disease: Coronary blood flow and myocardial ischemia. In: Zipe D Braunwald's Heart Disease, 7th ed. Philadelphia: Elsevier Saunders, 2005;1103-1127.5Koerselman J, van der Graaf Y, de Jaegere PP. Coronary collaterals: An important and underexposed aspect of coronary artery disease. Circulation. 2003;107:2507-2511. [View Abstract]6Meier P, Gloekler S, Zbinden R. Beneficial effect of recruitable collaterals. A 10 year follow up study in patients with stable coronary artery disease undergoing quantitative collateral measurements. Circulation. 2007;116:975-983. [View Abstract]7Rentrop KP, Cohen M, Blanke H. Changes in collateral channel filling immediately after controlled coronary artery occlusion by angioplasty balloon in human subjects. J Am Coll Cardiol. 1985;5:587-592. [View Abstract]8Rockstroh J, Brown G. Coronary collateral size, flow capacity, and growth. Estimates from the angiogram in patients with obstructive coronary disease. Circulation. 2002;105:168-173. [View Abstract]9Schaper W. Collateral vessel growth in the human heart. Role of fibroblast growth factor-2 editorial. Circulation. 1996;94:600-601. [View Abstract]10Schirmer SH, Nooijen FC, Piek JJ. Stimulation of collateral artery growth: Travelling further down the road to clinical application. Heart. 2009;95:191-197. [View Abstract]

459.89 Other specified circulatory system disorders

59093008 venous collateral circulation, any site (disorder)

  • Collateral blood vessels are anastomotic connections that offer an important source of blood supply when original vessels fail to provide sufficient blood, and are extremely important in the coronary circulation.
  • Coronary collateral vessels limit myocardial ischemia during coronary occlusion and may minimize the infarct area.
  • 2 types of coronary collateral vessels include:Capillary size collaterals: These vessels do not have vascular smooth muscle, are observed in all layers of the ventricular muscle (but have a predilection for the subendocardium where they form a plexus), and develop via angiogenesis.Larger muscular collaterals: These vessels are located epicardially, develop from preexisting arterioles (arteriogenesis), and can be angiographically classified into 4 types: Septal, atrial, branch-branch in ventricular free walls, and bridging across lesions.
  • Capillary size collaterals: These vessels do not have vascular smooth muscle, are observed in all layers of the ventricular muscle (but have a predilection for the subendocardium where they form a plexus), and develop via angiogenesis.
  • Larger muscular collaterals: These vessels are located epicardially, develop from preexisting arterioles (arteriogenesis), and can be angiographically classified into 4 types: Septal, atrial, branch-branch in ventricular free walls, and bridging across lesions.

Epidemiology

  • Collateral arteries that prevent signs of myocardial ischemia are present in 1/3 of patients with coronary disease and 1/5 of patients without coronary disease.
  • A reduction in coronary collaterals has been reported in the elderly and diabetics and is associated with a reduction in the expression of angiogenic factors.

Pathophysiology

  • Angiogenesis:Stimulated by hypoxia via biochemical signals including vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-β, and basic fibroblast growth factor (b-FGF).
  • Arteriogenesis:Not stimulated by hypoxia.Stimulated by an increase in shear stress (ie, hemodynamically relevant stenosis of coronary artery creates a decrease in arterial pressure distal to the stenosis and blood flow is redistributed through preexistent arterioles from high-pressure to low-pressure area. This creates increase in flow velocity and shear stress, which leads to morphological changes and vascular remodeling.Major biochemical factors include: GM-CSF, monocyte chemoattractant protein-1 (MCP-1), TGF-β
  • Stimulated by hypoxia via biochemical signals including vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-β, and basic fibroblast growth factor (b-FGF).
  • Not stimulated by hypoxia.
  • Stimulated by an increase in shear stress (ie, hemodynamically relevant stenosis of coronary artery creates a decrease in arterial pressure distal to the stenosis and blood flow is redistributed through preexistent arterioles from high-pressure to low-pressure area. This creates increase in flow velocity and shear stress, which leads to morphological changes and vascular remodeling.
  • Major biochemical factors include: GM-CSF, monocyte chemoattractant protein-1 (MCP-1), TGF-β

Etiology

  • Ischemia
  • Pressure gradients and shear stress

Associated Conditions

  • Coronary artery disease
  • Peripheral vascular disease

Diagnosis

Tests

  • Coronary angiography
  • Myocardial contrast echo
  • Spiral CT scan
  • MRI
  • PET scan
  • 1 = filling of side branches of the artery without visualization of the epicardial segment
  • 2 = partial filling of the epicardial segment
  • 3 = complete filling of the epicardial segment

Treatment

Additional Treatment

  • A pharmacological agent that could stimulate collateral vessel growth could have a major impact on morbidity and mortality.
  • Experimental studies have been promising; clinical research is ongoing.

Ongoing Care

Prognosis

  • Beneficial effects of collaterals include:Decrease the severity of myocardial ischemiaDecreased infarct sizeImprove LV functionReduce the likelihood of LV aneurysm formationImprove survival
  • Only rarely provides blood flow increases adequate to meet maximal physical exercise
  • Decrease the severity of myocardial ischemia
  • Decreased infarct size
  • Improve LV function
  • Reduce the likelihood of LV aneurysm formation
  • Improve survival

Additional Reading

Codes

ICD9

SNOMED

Clinical Pearls

  • The capillary-sized vessels are observed in all layers of the ventricular muscle, but have a predilection for the subendocardium where they form a plexus. The larger muscular collaterals are found epicardially.
  • There are two main types of collateral blood vessels: Capillary-sized vessels without smooth muscle and larger muscular vessels. The capillary-sized vessels form through angiogenesis stimulated hypoxia via biochemical signals including: VGEF, TGF-β, and b-FGF. The larger muscular vessels are nonfunctional pre-existing conduits that become functional in the setting of a hemodynamically significant stenosis. These larger vessels then undergo vascular remodeling in the setting of shear stress.
  • Studies have found a decrease in the severity of myocardial ischemia, a decreased infarct size, improved LV function, a reduction in the likelihood of LV aneurysm formation, and improved survival.