Studies on haematocrit in peripheral arterial disease

Area of Science:

• Vascular Medicine
• Hematology
• Rheology

Background:

• Peripheral arterial disease (PAD) is often associated with elevated hematocrit.
• Hematocrit influences blood viscosity and platelet behavior, key factors in PAD.

Purpose of the Study:

• To investigate the relationship between hematocrit and claudication, smoking, blood flow, platelet aggregation, and graft complications.
• To determine if elevated hematocrit in PAD is independently associated with adverse outcomes.

Main Methods:

• Comparative analysis of hematocrit, viscosity, and fibrinogen in claudicants versus controls.
• Venesection study in stable claudicants to assess effects on calf blood flow.
• Platelet aggregation studies using whole blood and single platelet counting.
• Retrospective analysis of pre-operative hematocrit in patients with aortic bifurcation graft complications.

Main Results:

• Claudicants exhibited higher blood viscosity, hematocrit, and fibrinogen, largely explained by higher smoking prevalence.
• Venesection in claudicants reduced hematocrit without significantly altering oxygen delivery to the calf.
• Elevated hematocrit in claudicants was not directly associated with increased platelet aggregation; a negative association was observed.
• Preliminary data suggest higher pre-operative hematocrit in patients with late aortic bifurcation graft complications.

Conclusions:

• The association of elevated hematocrit in PAD with adverse outcomes may be confounded by smoking and rheological factors.
• Hematocrit elevation in PAD does not appear to directly drive increased platelet aggregation.
• Further prospective studies are essential to elucidate the precise role of hematocrit in PAD and its complications.