In a 72‑year‑old non‑obese male with a low N‑terminal pro‑B‑type natriuretic peptide (NT‑proBNP) level and an E/A ratio of 0.69, what conclusions can be drawn about his diastolic function, and should he be evaluated for restrictive cardiomyopathy or constrictive pericarditis?

Assessment of a 72-Year-Old Male with E/A Ratio 0.69 and Low NT-proBNP

This patient's E/A ratio of 0.69 is consistent with Grade I diastolic dysfunction (impaired relaxation with normal or low left atrial pressure), and the low NT-proBNP strongly argues against restrictive cardiomyopathy but does NOT exclude constrictive pericarditis—he should be evaluated for constrictive pericarditis if clinically suspected. 1

Understanding the E/A Ratio Finding

The E/A ratio of 0.69 places this patient in a specific diagnostic category according to the 2016 ASE/EACVI guidelines:

• When E/A ratio ≤ 0.8 with peak E velocity ≤ 50 cm/sec: Left atrial pressure (LAP) is either normal or low, indicating Grade I diastolic dysfunction 1
• This represents impaired LV relaxation with normal filling pressures
• This is NOT a misdiagnosis—it is a real finding that is extremely common in elderly patients and represents the mildest form of diastolic dysfunction

The diastolic dysfunction diagnosis remains valid; what needs clarification is whether there's an underlying restrictive physiology.

The NT-proBNP and Differential Diagnosis

Why Low NT-proBNP Matters

The "very low" NT-proBNP reading is actually the key discriminating factor here:

For Restrictive Cardiomyopathy vs. Constrictive Pericarditis:

• Restrictive cardiomyopathy patients have markedly elevated NT-proBNP levels (mean 2,641 pg/mL in one study, median 1,775 pg/mL in another) 2, 3
• Constrictive pericarditis patients have significantly lower NT-proBNP levels (mean 628 pg/mL, median 124 pg/mL) 2, 3
• A cutoff of 459-800 pg/mL provides 86-90% sensitivity and specificity for differentiation 2, 3
• The 2022 meta-analysis confirmed BNP/NT-proBNP levels are significantly lower in constrictive pericarditis with pooled AUC of 0.81 4

Clinical Interpretation

If this patient's NT-proBNP is truly "very low" (presumably well below 459 pg/mL):

• This essentially rules out restrictive cardiomyopathy as the cause of his diastolic dysfunction 4, 2, 5, 3
• However, low NT-proBNP is consistent with constrictive pericarditis if other clinical features are present 4, 2, 5, 3

When to Pursue Constrictive Pericarditis Evaluation

You should evaluate for constrictive pericarditis if ANY of the following are present:

• History of pericarditis, cardiac surgery, chest radiation, or tuberculosis
• Physical exam findings: pericardial knock, Kussmaul's sign, prominent y descent on JVP
• Imaging showing pericardial thickening or calcification on CT/MRI
• Echocardiographic features: septal bounce, respiratory variation in mitral inflow >25%, hepatic vein expiratory diastolic flow reversal
• Elevated inflammatory markers (CRP >0.57 mg/dL favors constrictive pericarditis over restrictive cardiomyopathy) 2

The ASE guidelines specifically list "constrictive pericarditis" as one of the diagnostic conclusions that should be considered in the differential 1

Important Caveats About NT-proBNP in This Age Group

Age-related considerations for a 72-year-old:

• NT-proBNP naturally increases with age; at 70-79 years, the 97.5th percentile can reach 2,704 pg/mL in females and 6,792 pg/mL in males 6
• However, the median remains relatively modest (240-281 pg/mL at ≥80 years) 6
• Non-obesity is relevant: Lower BMI is associated with higher NT-proBNP levels; obese patients tend to have lower NT-proBNP 7, 8
• Since this patient is not obese, his low NT-proBNP is even more significant in ruling out restrictive cardiomyopathy

Algorithmic Approach

Step 1: Confirm the E/A ratio finding with additional parameters:

• Measure peak E velocity (if ≤50 cm/sec, confirms Grade I diastolic dysfunction with normal LAP) 1
• Check average E/e′ ratio, LA volume index, and TR jet velocity to confirm normal filling pressures 1

Step 2: If clinical suspicion exists for constrictive physiology:

• Obtain CT or cardiac MRI to assess pericardial thickness
• Perform comprehensive echocardiography with respiratory variation assessment
• Check inflammatory markers (CRP) 2

Step 3: If pericardial imaging is abnormal or high clinical suspicion persists:

• Consider cardiac catheterization with simultaneous LV/RV pressure measurements
• Look for ventricular interdependence and equalization of diastolic pressures

Bottom Line

The diastolic dysfunction is real and correctly diagnosed as Grade I. The low NT-proBNP makes restrictive cardiomyopathy highly unlikely but does not exclude constrictive pericarditis. Pursue constrictive pericarditis evaluation only if there are specific clinical, historical, or imaging features suggesting pericardial disease—not simply because the E/A ratio is low or NT-proBNP is unusual.