In a pregnant woman with rheumatic heart disease, what are the key echocardiographic findings that should be assessed antenatally to evaluate maternal and fetal risk?

Key Echocardiographic Findings in Pregnant Women with Rheumatic Heart Disease

In pregnant women with rheumatic heart disease, antenatal echocardiography must assess mitral valve area and gradient, left ventricular systolic function, pulmonary artery systolic pressure, and the presence and severity of any valvular regurgitation to stratify maternal and fetal risk. 1

Critical Echocardiographic Parameters to Assess

Mitral Stenosis Evaluation

• Mitral valve area (MVA): Severe rheumatic MS is defined as MVA ≤1.5 cm² and represents Stage D disease requiring close monitoring 1
• Mean pressure gradient: Document the mean gradient across the mitral valve, as gradients <5 mm Hg indicate mild disease while higher gradients suggest hemodynamically significant stenosis 1
• Valve morphology: Assess suitability for percutaneous balloon mitral commissurotomy (PMBC) if intervention becomes necessary during pregnancy 1

Left Ventricular Function Assessment

• LV ejection fraction: Severe LV dysfunction (EF <40%) combined with valvular disease represents high maternal and fetal risk 1
• Ventricular dimensions: Measure LV end-diastolic and end-systolic dimensions, as chamber enlargement beyond physiologic pregnancy changes indicates decompensation 1, 2
• Fractional shortening: Normal values >28% help distinguish physiologic from pathologic ventricular function 3

Pulmonary Hypertension Screening

• Pulmonary artery systolic pressure (PASP): PASP >50 mm Hg indicates depressed LV systolic function and high risk 1
• Severe pulmonary hypertension: Pulmonary pressure >75% of systemic pressures represents one of the highest-risk conditions in pregnancy with significant maternal mortality 1
• Tricuspid regurgitation velocity: Use continuous-wave Doppler to estimate right ventricular systolic pressure 2

Valvular Regurgitation Assessment

• Mitral regurgitation severity: Grade the degree of MR using color Doppler, as severe MR with LV dysfunction is poorly tolerated 1
• Aortic regurgitation: Assess AR severity and LV response, though regurgitant lesions are generally better tolerated than stenotic lesions due to decreased systemic vascular resistance in pregnancy 1
• Functional regurgitation: Distinguish structural valve disease from functional regurgitation secondary to annular dilatation, which is common in normal pregnancy 1

High-Risk Echocardiographic Findings

Findings Requiring Tertiary Care Management

• Severe AS with mean gradient ≥40 mm Hg (Stage D) 1
• Severe rheumatic MS (MVA ≤1.5 cm²) with NYHA class III-IV symptoms despite medical therapy 1
• Severe valve regurgitation with NYHA class IV HF symptoms refractory to medical therapy 1
• Pulmonary hypertension of any cause, which carries extremely high maternal mortality risk 1
• LV ejection fraction <30% with NYHA III-IV symptoms 1

Prosthetic Valve Assessment

• Mechanical prostheses: Evaluate for prosthetic valve obstruction or thrombus formation using transesophageal echocardiography (TEE) if embolic events occur 1
• Valve gradients: Document baseline and serial gradients across prosthetic valves, as increased gradients may indicate obstruction or pannus formation 1

Serial Monitoring Protocol

Frequency of Echocardiographic Surveillance

• Every trimester: Minimum frequency for women with known valvular disease to assess progression 1
• Every 4-8 weeks: For women with moderate to severe stenotic lesions or those with symptoms 1, 4
• Monthly to bimonthly: For high-risk patients with severe disease or LV dysfunction 3

Parameters to Track Serially

• Changes in valve area and gradients, as pregnancy-related increases in blood volume and cardiac output can worsen stenotic lesions 1, 2
• Progressive LV dilatation or declining systolic function 2
• Development or worsening of pulmonary hypertension 4
• New or worsening valvular regurgitation 1

Common Pitfalls to Avoid

• Do not attribute physiologic pregnancy changes to pathology: Normal pregnancy causes mild ventricular enlargement, physiologic tricuspid and pulmonic regurgitation, and mild MR from annular dilatation 1
• Do not miss severe MS: The increased cardiac output of pregnancy accentuates murmurs of stenotic lesions, making clinical detection easier, but echocardiography remains essential for quantification 1
• Do not underestimate pulmonary hypertension: This represents the highest-mortality cardiac condition in pregnancy and requires intensive multidisciplinary management 1, 4
• Do not delay intervention in deteriorating patients: Women with severe symptomatic MS who remain NYHA class III-IV despite medical therapy should undergo PMBC during pregnancy at a comprehensive valve center 1