Hemodynamic Changes in Pregnancy and Mitral Stenosis

Pathophysiology of Mitral Stenosis in Pregnancy

Cardiac output increases 30-50% during normal pregnancy, with stroke volume being the primary driver in early pregnancy, according to the European Society of Cardiology 1
In mitral stenosis, the fixed stenotic valve cannot accommodate the increased blood flow volume, creating a critical mismatch and leading to elevated left atrial pressure, pulmonary venous congestion, and ultimately pulmonary edema, as stated by the European Heart Journal 2
The result of this mismatch is that the heart attempts to increase stroke volume to meet metabolic demands, but the stenotic mitral valve acts as a fixed obstruction, causing heart failure, as reported by the European Heart Journal 2

Heart failure in mitral stenosis typically manifests between the third and fifth months of pregnancy, corresponding precisely to when cardiac output increases are maximal, according to the European Heart Journal 3
Approximately 50% of patients with severe mitral stenosis are not the focus, however, mortality ranges from 0-3% in mitral stenosis during pregnancy, with morbidity significantly higher, as stated by the European Society of Cardiology 2, 4

Monthly or bimonthly echocardiographic follow-up is indicated to assess hemodynamic tolerance, as recommended by the European Society of Cardiology 2
Percutaneous mitral commissurotomy should be considered after 20 weeks gestation in patients with NYHA class III/IV symptoms despite optimal medical treatment, according to the European Heart Journal 2, 4
Activity restriction should be implemented when symptoms or pulmonary hypertension (systolic PAP >50 mmHg) develop, as stated by the European Society of Cardiology 2