What are high-risk clinical and echocardiographic features in pregnant patients with congenital heart disease?

The most commonly used risk stratification tool available has been the mWHO maternal cardiovascular risk classification which places women into different categories (I-IV) based on diagnosis/ residual lesions. Class IV patients are considered very high risk for cardiovascular events (bleeding, thromboembolic events, arrhythmias, heart failure, etc). Pregnancy in patients who are in Class IV would be considered contraindicated. These features include: pulmonary arterial hypertension, severe syste...