Diabetes mellitus is a systemic disease with profound vascular implications. Understanding how diabetes affects the vascular system—especially in the lower extremities—is essential for early detection, prevention, and management of complications in our patients. Below is a concise review for your clinical practice.
Overview
Chronic hyperglycemia in diabetes leads to widespread vascular dysfunction, affecting both large (macrovascular) and small (microvascular) blood vessels. The lower legs are particularly vulnerable, resulting in significant morbidity.
Pathophysiology
Macrovascular Disease
- Atherosclerosis: Diabetes accelerates the process of atherosclerosis, leading to narrowed and stiffened arteries.
- Peripheral Arterial Disease (PAD): Lower extremities are commonly affected, with increased risk of arterial occlusion, ischemia, and poor wound healing.
Microvascular Disease
- Capillary Basement Membrane Thickening: Leads to reduced oxygen and nutrient delivery to tissues.
- Impaired Vasodilation: Endothelial dysfunction reduces nitric oxide availability, further limiting blood flow.
Effects on Lower Leg Vasculature
- Decreased Perfusion: Both macro- and microvascular changes reduce blood flow to the skin and muscles of the lower legs and feet.
- Delayed Wound Healing: Poor perfusion impairs the body’s ability to heal minor injuries, increasing the risk of chronic ulcers.
- Increased Risk of Infection: Diminished immune cell access to tissues makes infections more common and severe.
- Claudication and Rest Pain: Patients may experience pain with walking (claudication) or even at rest, indicating critical limb ischemia.
- Diabetic Foot Ulcers: Combined with neuropathy, vascular compromise is a leading cause of diabetic foot ulcers and subsequent amputations.
Clinical Assessment
- History: Ask about claudication, rest pain, non-healing wounds, and previous ulcers or amputations.
- Physical Exam:
- Inspect for hair loss, shiny skin, color changes, ulcers, and gangrene.
- Palpate pulses (dorsalis pedis, posterior tibial).
- Assess capillary refill and temperature.
- Non-Invasive Testing:
- Duplex ultrasonography for arterial flow assessment.
- Ankle-Brachial Index (ABI) for PAD screening. ABI’s are not recommended in diabetic patients due to arterial thickening. This can cause a falsely elevated ABI result. We recommend performing arterial US as first line testing in all diabetic patients.
Management Strategies
- Glycemic Control: Tight glucose management reduces the progression of vascular disease.
- Risk Factor Modification: Address hypertension, hyperlipidemia, and smoking cessation.
- Foot Care: Daily inspection, prompt treatment of minor injuries, and patient education.
- Referral: Early vascular referral for non-healing wounds, ulcers, or signs of critical limb ischemia.
- Revascularization: Consider patients with severe PAD and non-healing ulcers.
Key Takeaways
- Diabetes significantly increases the risk of both macrovascular and microvascular disease, especially in the lower legs.
- Early detection and aggressive management of vascular risk factors are crucial to prevent limb-threatening complications.
- Routine foot and vascular assessments should be part of every diabetic patient’s care plan.
Please share this information with your care team members and incorporate these strategies into your diabetes management protocols. For further reference, see the resources below.
References:
- American Diabetes Association. Standards of Medical Care in Diabetes—2025.
- UpToDate: Peripheral Artery Disease in Patients with Diabetes.
- American Heart Association. Diabetes and Vascular Disease.