Why screening for blocked arteries matters
Atherosclerosis—plaque buildup in the arteries—can limit blood flow to the heart, brain, and limbs. Many people have no symptoms until a major event such as a heart attack or stroke. Non‑invasive tests help detect risk and disease early, guiding lifestyle and medical treatment before complications occur.
Who should consider testing
- Adults with chest discomfort, breathlessness on exertion, or unexplained fatigue
- People with risk factors: diabetes, high blood pressure, high LDL cholesterol, smoking, kidney disease, obesity, sleep apnea, inflammatory conditions, or a strong family history of early heart disease
- Men over 45 and women over 55, especially with multiple risk factors
- People with leg pain when walking (possible peripheral artery disease), or known carotid bruits
Always consult your clinician about which test is appropriate for your situation; not everyone needs every test.
The 4 essential non‑invasive tests
1) Coronary Artery Calcium (CAC) Score
What it is: A fast, non‑contrast CT scan that measures calcified plaque in the coronary arteries.
What it shows: Your total calcium “score” (Agatston score) reflects lifetime plaque burden and future heart attack risk.
- Score 0: Very low short‑term risk; lifestyle focus; medications depend on overall risk.
- 1–99: Mild plaque; consider intensifying prevention (statin often recommended if other risks present).
- 100–299: Moderate plaque; stronger indication for statins and risk‑factor control.
- ≥300 or ≥75th percentile for age/sex: High risk; aggressive prevention warranted.
Pros: Quick (5–10 min), no needles or contrast, low radiation, powerful for risk reclassification.
Limitations: Detects calcified plaque only (not soft plaque), does not show exact narrowing or blood‑flow impact, not ideal if you’re already very high risk (treatment is indicated regardless).
2) Coronary CT Angiography (CCTA)
What it is: A contrast‑enhanced CT that directly visualizes coronary arteries, identifying both calcified and soft plaques and estimating the severity of any narrowing.
What it shows: Presence, location, and extent of plaque; whether a lesion is likely obstructive; sometimes plaque characteristics linked to higher risk.
Who benefits: People with intermediate likelihood of coronary disease, persistent symptoms with unclear cause, or inconclusive stress tests.
Pros: Excellent anatomical detail; can rule out significant coronary disease with high confidence.
Limitations and safety: Requires IV contrast (use caution in significant kidney disease or iodine allergy), involves radiation, accuracy can be reduced by heavy calcification or very fast/irregular heart rhythms.
Advanced options: In select cases, computational analysis (FFR‑CT) can estimate the blood‑flow impact of lesions without an invasive procedure.
3) Exercise Stress Testing (with or without Imaging)
What it is: Treadmill or bicycle exercise while monitoring ECG and symptoms. If needed, imaging is added via echocardiography (ultrasound) or nuclear perfusion imaging to see how the heart muscle responds to stress.
What it shows: Evidence of reduced blood flow during exertion (ischemia). Imaging variants assess wall motion (stress echo) or blood supply (nuclear SPECT/PET).
- Plain exercise ECG (TMT/ETT): Useful if you can exercise adequately and have an interpretable baseline ECG.
- Stress echocardiography: No radiation; detects exercise‑induced wall motion changes.
- Nuclear perfusion: Sensitive for detecting flow deficits; involves small radiation exposure.
Pros: Functional assessment of how arteries perform under stress; helps gauge symptom significance and exercise capacity.
Limitations: Less informative if you cannot exercise enough; ECG alone can miss disease or give false positives; imaging availability varies.
4) Ankle‑Brachial Index (ABI) with Doppler
What it is: A bedside test comparing blood pressure at the ankle with the arm; often paired with Doppler ultrasound to view blood flow in leg arteries.
What it shows: Blockages or stiffness in leg arteries, a strong marker of systemic atherosclerosis.
- ABI ≤ 0.90: Peripheral artery disease (PAD) likely.
- 0.91–0.99: Borderline.
- 1.00–1.40: Normal.
- > 1.40: Non‑compressible (calcified) arteries; consider toe‑brachial index or imaging.
Pros: Quick, inexpensive, no radiation or needles; predicts cardiovascular risk beyond the legs.
Limitations: May be falsely high in diabetes or chronic kidney disease due to arterial stiffness; follow‑up Doppler ultrasound helps clarify.
Other helpful non‑invasive tests
- Carotid ultrasound (duplex): Detects plaque and narrowing in neck arteries; presence indicates higher overall vascular risk.
- Echocardiogram (resting): Shows heart structure and function; indirect clues to coronary disease (e.g., wall motion issues), valves, and pumping strength.
- Blood tests: Lipid profile, A1c, and high‑sensitivity CRP help estimate risk and guide prevention, though they don’t show blockages directly.
Choosing the right test
The “best” test depends on your symptoms, baseline risk, age, ability to exercise, kidney function, and local expertise. As a general guide:
- Risk clarification without symptoms: CAC score is often first‑line.
- Persistent chest symptoms with intermediate risk: Stress testing or CCTA; your clinician will tailor the choice.
- Leg symptoms on exertion: ABI with Doppler is the initial test.
- Concern for stroke risk or known vascular disease elsewhere: Consider carotid ultrasound.
How to prepare and what to expect
- CAC/CCTA: Avoid caffeine before the exam; you may receive medication to slow heart rate. Tell your team about kidney disease or contrast allergies (CCTA).
- Stress tests: Wear comfortable clothing and shoes; avoid heavy meals and caffeine beforehand; ask about holding certain medications.
- ABI/Doppler: No special preparation; you’ll rest supine while cuffs and Doppler are used.
Interpreting results and next steps
Normal results lower the likelihood of significant blockages in the tested area but don’t eliminate future risk. Continue heart‑healthy habits.
Abnormal results may lead to intensified prevention (statins, blood pressure and diabetes control, smoking cessation), targeted exercise therapy, or further testing. In some cases, doctors may recommend invasive angiography to plan stenting or surgery.
When to seek urgent medical care
- Chest pressure, tightness, or pain especially with exertion or stress
- Pain spreading to jaw, neck, arms, back, unusual breathlessness, cold sweats, nausea
- Sudden weakness, facial droop, speech difficulty (possible stroke)
- Severe leg pain with cold, pale limb (acute arterial blockage)
If you experience these signs, call emergency services immediately.
Take‑home message
Blocked arteries are often silent but detectable. Four non‑invasive tests—coronary calcium scoring, coronary CT angiography, exercise stress testing (with or without imaging), and the ankle‑brachial index with Doppler—offer complementary insights. Talk to your clinician about which test matches your symptoms and risk profile, then act on the results with proven prevention strategies.
