What are the causes of decreased vascular flow, also known as hypoperfusion?

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, which can lead to inadequate blood flow and increased risk of morbidity and mortality 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
• Lesions within the anastomotic area, such as juxta-anastomotic venous stenosis
• Surgical factors, including the expertise of the surgeon and the location of the anastomosis
• Patient-related factors, such as diabetes mellitus, hypertension, and female sex Treatment of decreased vascular flow depends on the underlying cause, but may include:
• Medications, such as antiplatelet drugs and anticoagulants
• Lifestyle modifications, including regular exercise, smoking cessation, and a heart-healthy diet
• Interventional procedures, such as angioplasty with stent placement or bypass surgery
• Revision of the arteriovenous anastomosis to a more proximal location It is essential to address decreased vascular flow promptly to prevent ischemia, cell damage, and potentially tissue death, as well as to reduce the risk of morbidity and mortality 1. In addition to the causes mentioned above, other factors can contribute to decreased vascular flow, such as:
• Cerebral hypoperfusion, which can result from an abnormally high cerebral vascular resistance or low carbon dioxide tension 1
• Orthostatic hypotension, which can occur due to impaired capacity to increase vascular resistance during standing 1
• Autonomic neuropathies, which can affect the regulation of blood flow and blood pressure 1 However, the most critical factor in decreased vascular flow is the impairment of arterial inflow, which can be caused by various factors, including arterioatherosclerotic narrowing and stenosis of the feeding artery 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 ischemia and reperfusion injury, which can lead to a local and systemic inflammatory response, resulting in tissue injury 3
• Stenosis or occlusion of blood vessels, which can lead to a significant reduction in quality of life and increased risk of morbidity and mortality 4
• Native arterial thrombosis, arterial thrombosis after an intervention, arterial embolus, and arterial injury, which are all etiologies of acute limb ischemia 5
• Complex percutaneous coronary intervention (PCI) and high bleeding risk (HBR), which can increase the risk of thrombotic and bleeding events 6

Mechanisms of Hypoperfusion

The mechanisms of hypoperfusion can be complex and involve various physiological and pathological processes. Some of the key mechanisms include:

• Oxidant production, complement activation, leucocyte-endothelial cell adhesion, platelet-leucocyte aggregation, increased microvascular permeability, and decreased endothelium-dependent relaxation, which are all characteristics of ischemia-reperfusion injury 3
• Cellular damage and necrosis, which can result from acute limb ischemia and lead to limb loss and potentially systemic symptoms 5
• Thrombotic composite end point, which includes cardiovascular death, nonfatal myocardial infarction, stroke, readmission due to acute coronary syndrome, and definite/probable stent thrombosis, and is a key outcome measure in patients with HBR and/or complex PCI 6

Risk Factors for Hypoperfusion

Several risk factors can increase the likelihood of hypoperfusion, including:

• High bleeding risk (HBR) and complex percutaneous coronary intervention (PCI), which can increase the risk of thrombotic and bleeding events 6
• Native arterial thrombosis, arterial thrombosis after an intervention, arterial embolus, and arterial injury, which are all etiologies of acute limb ischemia 5
• Stenosis or occlusion of blood vessels, which can lead to a significant reduction in quality of life and increased risk of morbidity and mortality 4
• Thrombosis superimposed on arteriosclerosis, which is the principal cause of mortality and morbidity in patients with arteriosclerosis 2