Are there studies reporting sensitivity, specificity, positive predictive value, and negative predictive value of exercise stress testing with imaging and VO₂‑max thresholds for detecting a reduced left ventricular ejection fraction (<50%) in patients with coronary artery disease?

Limited Evidence for Sensitivity/Specificity of Exercise Stress Testing with Imaging and VO₂-max for Detecting Reduced LVEF in CAD

The available evidence does not provide specific sensitivity, specificity, or predictive values for exercise stress testing with imaging or VO₂-max thresholds in detecting reduced left ventricular ejection fraction (<50%) in patients with coronary artery disease. The existing literature focuses primarily on detecting obstructive CAD or ischemia rather than LVEF reduction as the outcome measure.

What the Evidence Actually Shows

Exercise ECG Testing Performance (for CAD Detection, Not LVEF)

The 2024 ESC guidelines report that exercise ECG has sensitivity of 58% and specificity of 62% for detecting obstructive CAD 11. However, this addresses a different clinical question than detecting reduced LVEF.

Stress Echocardiography Performance (for CAD Detection)

For women with suspected CAD, stress echocardiography demonstrates:

• Exercise stress echo: sensitivity 79% (95% CI 74-83%), specificity 83% (95% CI 74-89%) 22
• Dobutamine stress echo: sensitivity 80% (95% CI 77-83%), specificity 84% (95% CI 80-86%) 22

Again, these metrics evaluate CAD detection, not LVEF assessment.

Nuclear Imaging Performance (for CAD Detection)

Exercise SPECT and PET show sensitivity 87-90% and specificity 73-89% for coronary stenoses ≥50% 3. Rb-82 PET/CT can assess stress LVEF and myocardial blood flow 4, but specific diagnostic accuracy for detecting LVEF <50% is not reported.

The Critical Gap in Your Question

The fundamental issue is that exercise stress testing with imaging is designed and validated for detecting myocardial ischemia and obstructive CAD, not for diagnosing reduced LVEF. The studies you're asking about simply don't exist in the provided evidence or mainstream literature because:

1. Resting echocardiography is the gold standard for measuring LVEF with Class I, Level B recommendation 1
2. LVEF is measured directly at rest, not inferred from stress testing
3. Stress testing evaluates functional reserve and ischemia, not baseline systolic function

What We Do Know About LVEF and Exercise

VO₂max Correlates with Exercise LVEF Reserve

One older study 5 found that in asymptomatic CAD patients:

• VO₂max was 21 ± 4 ml/kg/min in those whose LVEF decreased with exercise
• VO₂max was 27 ± 4 ml/kg/min in those whose LVEF increased (p<0.001)
• Left ventricular exercise reserve (change in LVEF from rest to exercise) correlated with VO₂max (r=0.77, p<0.0002)

However, this doesn't provide sensitivity/specificity for detecting resting LVEF <50%.

Recent Research on LVEF Changes During Stress

A 2026 study 6 examining the "grey zone" between physiological adaptation and early dilated cardiomyopathy found:

• Failure to increase LVEF ≥10% from rest to peak exercise identified DCM with 79.4% sensitivity and 98.3% specificity
• Adding submaximal-to-peak augmentation improved sensitivity to 98.2% and specificity to 98.4%

But this addresses contractile reserve in dilated cardiomyopathy, not detecting baseline LVEF <50% in CAD.

Clinical Approach When LVEF Assessment is Needed

If you need to determine whether a CAD patient has LVEF <50%, perform resting transthoracic echocardiography 1. This is:

• Class I, Level B recommendation
• Direct measurement, not inference
• Provides LVEF, volumes, diastolic function, and regional wall motion abnormalities

Stress testing serves different purposes:

• Risk stratification in known CAD
• Detecting inducible ischemia
• Assessing functional capacity and prognosis
• Evaluating contractile reserve (particularly in heart failure evaluation)

When Stress Testing Adds Value in Reduced LVEF

In patients with known reduced LVEF:

• Cardiopulmonary exercise testing quantifies functional limitation and aids heart transplant/mechanical support selection 7
• Dobutamine stress echo assesses viability with biphasic response showing 74% sensitivity and 89% specificity for predicting functional recovery 8

Bottom Line

No studies report sensitivity, specificity, PPV, or NPV of exercise stress testing with imaging or VO₂-max thresholds specifically for detecting LVEF <50% in CAD patients because this is not the intended use of these tests. Resting echocardiography directly measures LVEF and should be your first-line test. Stress testing evaluates ischemia, functional capacity, and prognosis—complementary but distinct clinical questions.