Causes & Risk Factors of PAD

Snapshot

Underlying mechanism: PAD develops when fatty plaque builds up inside the arterial walls, causing them to narrow & is known as atherosclerosis.
Primary cause: The disease most often begins in the arteries of the legs, where plaque accumulation limits oxygen delivery to muscles during activity.
Major risk factors: Smoking, diabetes, high blood pressure and high cholesterol are the leading contributors.
Contributing influences: Ageing, family history of vascular disease, chronic kidney disease and a sedentary lifestyle further increase vulnerability to PAD.

Synopsis

You must have heard of someone experiencing a heart attack and undergoing angioplasty to clear the blocked artery. Similarly, Peripheral Artery Disease (PAD) affects the arteries in your legs/arms instead of the heart. Peripheral Artery Disease (PAD) occurs when plaque buildup causes narrowing of arteries, reducing blood flow to the legs or arms. The top 5 risk factors include smoking, diabetes, hypertension, high cholesterol and age above 50yrs. PAD also signals broader susceptibility to vascular disease, raising the risk of heart attack and stroke.

What is Peripheral Artery Disease?

Peripheral Artery Disease (PAD) refers to the partial or complete blockage of peripheral arteries, most often in the legs or arms, due to plaque buildup. This plaque, also called atherosclerosis, is composed of cholesterol, fat, calcium and fibrous tissue. It narrows the arterial lumen and limits the supply of oxygen and nutrients to the muscles.

Peripheral Artery Disease (PAD) affects multiple blood vessels throughout the body. And that’s why people with PAD often also have arterial narrowing or blockages elsewhere. For example:

Affecting the heart – Coronary artery disease
Affecting the brain – Cerebrovascular disease
Affecting arteries in the neck – Carotid artery disease
Affecting groin area – Erectile dysfunction & male infertility

Symptoms of Peripheral Artery Disease

Peripheral arterial disease symptoms can range from a symptom-free state to developing critical limb ischaemia with rest pain or ulcers. The following symptoms progress in severity as blood flow continues to reduce:

No symptoms: The body can still compensate.
Intermittent Claudication: Pain or cramping develops in the legs (or arms) after walking a short distance.
Rest Pain: Persistent foot pain even when at rest
Skin and Tissue Changes: Pale, cool limbs, brittle nails, hair loss on legs
Weak or Absent Pulses: Diminished pulses

Causes of Peripheral Artery Disease

The primary cause of PAD is atherosclerosis, a process in which the inner lining of the artery or endothelium becomes inflamed due to damage by factors such as high cholesterol, smoking or high blood pressure. This triggers lipid deposition, plaque formation and gradual narrowing of the arterial lumen, reducing oxygen supply to tissues.

Atherosclerosis

Plaque buildup in the arteries narrows vessels and restricts blood flow.
Plaque is composed of fat, calcium, blood cells and fibrous tissue.
When plaque ruptures, it can cause clots that may obstruct circulation completely.

Other (Less Common) Causes

Vasculitis: Arterial inflammation causing narrowing or scarring.
Embolism: A blood clot travelling from another site blocks an artery.
Trauma or Radiation Injury: Damage to arterial walls from direct impact or radiation therapy.
Fibromuscular Dysplasia: Abnormal cell growth within artery walls leading to narrowing or blockage.

Metabolic and Inflammatory Contributors

Certain underlying health conditions can accelerate the buildup of plaque in the arteries and lead to further damage to blood vessels. These include:

Long-term inflammation in the body
Abnormal cholesterol levels
High levels of homocysteine (an amino acid) in the blood
Blood disorders that increase the tendency for clot formation

Risk Factors of Peripheral Artery Disease

Risk factors for PAD mirror those of other atherosclerotic diseases, such as coronary artery disease and stroke, and can be grouped into modifiable and non-modifiable categories.

Modifiable Risk Factors

These can be improved or controlled through lifestyle and medical intervention:

Smoking: The single most significant risk factor. Nicotine damages blood vessel walls, raises blood pressure and constricts arteries. Even secondhand smoke increases risk.
Diabetes Mellitus: Chronic high blood sugar injures arterial linings, accelerates plaque formation and impairs circulation. Poorly controlled diabetes increases the likelihood of critical limb ischaemia and amputation.
High Blood Pressure (Hypertension): Persistent high pressure weakens arteries and fosters plaque deposition.
High Cholesterol: Elevated LDL (“bad” cholesterol) and triglycerides (a type of fat stored in the blood) promote atherosclerotic buildup.
Obesity: Excess body weight contributes to hypertension, diabetes and dyslipidaemia, all precursors of PAD.
Physical Inactivity: A sedentary lifestyle reduces muscle oxygen demand, weakens collateral circulation and increases the risk of vascular stiffening.
Unhealthy Diet & Stress: Diets rich in saturated fats and chronic stress contribute to vascular inflammation and elevated cholesterol.

Non-Modifiable Risk Factors

Age: Risk rises sharply after age 50 and even more after 65 due to progressive arterial stiffening.
Family History & Genetics: A family history of PAD, coronary artery disease or stroke increases susceptibility. Genetic mutations like Factor V Leiden can predispose to thrombosis.
Chronic Kidney Disease (CKD): CKD promotes vascular calcification and inflammation, making PAD more severe and difficult to treat.
Race & Ethnicity: PAD prevalence is higher in black individuals and in American Indian women. Sedentary Hispanic adults also show elevated risk. Moreover, the prevalence rate ranges between 15% to 25% in Indian citizens.
Blood Clotting Disorders: Conditions like antiphospholipid syndrome (an autoimmune disorder causing blood clots) or thrombocytosis (a condition with an abnormally high platelet count) can cause arterial blockages.
Elevated Homocysteine: High levels of this amino acid damage the endothelium and accelerate atherosclerosis.
HIV Infection: Chronic inflammation and medication effects may contribute to premature arterial disease.

Modifiable Risk Factors	Non-Modifiable Risk Factors
Smoking	Age
Diabetes Mellitus	Family History & Genetics
High Blood Pressure (Hypertension)	Chronic Kidney Disease (CKD)
High Cholesterol	Race & Ethnicity
Obesity	Blood Clotting Disorders (e.g., Antiphospholipid Syndrome, Thrombocytosis)
Physical Inactivity	Elevated Homocysteine
Unhealthy Diet & Stress	HIV Infection

What Is the Best Treatment for Peripheral Artery Disease?

A combination approach works best for the treatment of PAD, focusing on improving circulation, relieving discomfort and preventing future cardiovascular complications:

Risk-Factor Control: Quit smoking, manage diabetes, blood pressure and cholesterol.
Exercise Therapy: Regular walking improves circulation and reduces leg pain.
Revascularisation: Angioplasty, stenting or bypass surgery restores blood flow.
Wound Care: Proper ulcer management prevents infection and limb loss.

What Are the 5 P’s of Peripheral Arterial Disease?

These classic signs reflect acute or severe arterial insufficiency:

Pain: Ischaemic, often severe
Pallor: Pale, cool skin
Pulselessness: Absent distal pulses
Paresthesia: Numbness or tingling
Paralysis/Poikilothermia: Muscle weakness or inability to maintain temperature

How To Prevent Leg Pain Due to PAD?

Stop Smoking: Cessation slows disease progression.
Stay Active: Regular walking enhances circulation and endurance.
Manage Health Conditions: Control diabetes, hypertension and cholesterol levels.
Balanced Diet: Follow a heart-healthy eating plan such as the DASH (Dietary Approaches to Stop Hypertension) or Mediterranean Diet.
Weight & Stress Management: Maintain a healthy BMI and practice relaxation techniques to support vascular health.

Is Peripheral Artery Disease Reversible?

PAD cannot be completely reversed, but its progression can be slowed. With sustained lifestyle changes, regular exercise and appropriate medical care, symptoms can be managed effectively and the risk of complications significantly reduced. Prompt revascularisation using peripheral angioplasty/bypass is essential in critical limb ischaemia (CLI) to prevent tissue loss. CLI is a severe stage of PAD where blood flow to the leg is greatly reduced, causing pain & risk of gangrene.

How Do You Diagnose Peripheral Artery Disease?

Diagnosis involves simple bedside and imaging tests:

Ankle–Brachial Index (ABI): Compares blood pressure in the ankle & arm; an ABI ≤ 0.90 confirms PAD.
Duplex Ultrasound: Detects blockages and measures blood flow.
CT or MR Angiography: Provides detailed arterial maps for surgical or endovascular planning.

Take Home Message

Peripheral Artery Disease reflects systemic vascular damage, not just a leg problem, but a sign of broader cardiovascular risk. By identifying and addressing risk factors like smoking, diabetes and inactivity early, progression can be halted and quality of life preserved. Awareness, early diagnosis and proactive management remain key to preventing the severe consequences of advanced PAD.

FAQs

What Is the Most Common Cause of Arterial Disease?

Atherosclerosis, the gradual buildup of cholesterol-rich plaque within the arterial walls, is the primary cause of peripheral artery disease (PAD) and most other arterial conditions. Over time, this plaque hardens and narrows the arteries, restricting blood flow.

This process not only causes PAD but also underlies coronary artery disease and carotid artery disease, making it a systemic vascular problem.

What Are the Four Stages of PAD?

PAD progresses through four key stages that reflect the severity of arterial obstruction:

Asymptomatic arterial narrowing: Blood flow begins to reduce, but no noticeable symptoms occur.
Intermittent claudication: Pain, cramping, or fatigue develops in the legs during walking or exercise and eases with rest.
Rest pain: Discomfort persists even at rest, particularly at night, indicating advanced ischemia.
Tissue loss (ulcers or gangrene): Severe oxygen deprivation leads to non-healing wounds or gangrene, posing a risk of amputation.

These stages align with the Fontaine or Rutherford classification systems used by vascular surgeons clinically to assess disease progression

What Are the Long-Term Effects of PAD?

If left untreated, PAD can result in serious limb-related complications such as critical limb ischaemia and amputation. It may also affect circulation in the groin region, contributing to erectile dysfunction, male infertility, and carotid artery-related stroke.

In advanced stages, PAD is also associated with a higher risk of heart attack due to underlying cardiovascular disease. Persistent poor circulation weakens tissues and slows healing, increasing the risk of ulcers and infections.
Moreover, since atherosclerosis affects multiple vascular beds, PAD often indicates a higher risk of systemic cardiovascular disease. Early detection and management of risk factors like smoking, diabetes and high cholesterol are crucial to prevent these outcomes.