From the Guidelines
Decreased vascular flow, also known as hypoperfusion, is primarily caused by impaired arterial inflow, arterioatherosclerotic narrowing of the feeding artery, and stenosis of the artery, as well as lesions within the anastomotic area 1. The causes of decreased vascular flow can be multifactorial, including:
- Impaired arterial inflow related to the site of cannulation
- Arterioatherosclerotic narrowing of the feeding artery with reduced flow and stenosis of the artery, commonly found in elderly patients, those with hypertension, and patients with diabetes 1
- Lesions within the anastomotic area, such as juxta-anastomotic venous stenosis, which can occur due to changes in hemodynamic flow character from the artery into the vein and devascularization of the venous wall during exposure 1
- Surgical factors, including the expertise of the surgeon, with studies showing that the early failure rate of fistula may be 3-fold greater when constructed by "occasionally" working access surgeons compared to experienced surgeons 1
- Patient-related factors, such as peripheral location of the first fistula, female sex, diabetes mellitus, and surgical expertise, which are predictive of early fistula failure 1 It is essential to identify and address the underlying cause of decreased vascular flow to prevent complications such as ischemia, cell damage, and potentially tissue death if left untreated. Treatment options may include interventional procedures like angioplasty, stenting, or bypass surgery, as well as lifestyle modifications and medications to manage underlying conditions like hypertension, diabetes, and hyperlipidemia. In cases of reduced flow caused by arterial inflow, therapeutic options exist, including stenosis of the feeding artery, which may require interventional angioplasty or surgical revision, or inadequate quality of the feeding artery, which may require a more proximally located new AV anastomosis 1.
From the Research
Causes of Decreased Vascular Flow
The causes of decreased vascular flow, also known as hypoperfusion, can be attributed to various factors. Some of the key causes include:
- Thrombosis superimposed on arteriosclerosis, which is the principal cause of mortality and morbidity in patients with arteriosclerosis 2
- Vascular stenosis or occlusion, which can lead to reduced blood flow and tissue injury 3
- Ischemia-reperfusion injury, which can occur when blood flow is restored to an ischemic organ, leading to a local and systemic inflammatory response 4, 5
- Damage to small-diameter blood vessels, which can be addressed by endovascular approaches or autologous vascular substitutes 3
Mechanisms of Hypoperfusion
The mechanisms of hypoperfusion are complex and involve various cellular and molecular changes. Some of the key mechanisms include:
- Oxidant production, complement activation, leucocyte-endothelial cell adhesion, platelet-leucocyte aggregation, and increased microvascular permeability 4
- Endothelial dysfunction, which can lead to decreased endothelium-dependent relaxation and increased vascular tone 4, 5
- Platelet activation and aggregation, which can contribute to thrombosis and vascular occlusion 2, 6
Clinical Implications
The clinical implications of hypoperfusion are significant and can lead to various cardiovascular events, including myocardial infarction, stroke, and peripheral vascular disease. Some of the key clinical implications include:
- The need for antiplatelet and anticoagulant therapy to prevent thrombosis and vascular occlusion 2, 6
- The importance of timely reperfusion and restoration of blood flow to ischemic organs 4, 5
- The potential benefits of tissue engineering and regenerative medicine in addressing vascular damage and promoting vascular repair 3