Group 5 Pulmonary Hypertension Resulting From Thyrotoxicosis During Pregnancy

BACKGROUND: We present a case of uncontrolled hyperthyroidism during pregnancy associated with heart failure with preserved ejection fraction and pulmonary hypertension (pHTN). CASE SUMMARY: A 32-year-old woman at 22 weeks' gestation was nonadherent to hyperthyroid medications. She presented with shortness of breath and was found to have pHTN on transthoracic echocardiography. Right heart catheterization revealed post-capillary pHTN, an elevated pulmonary artery occlusion pressure (33 mm Hg), and high cardiac output, consistent with group 5 pHTN. She was managed with antithyroid medications, corticosteroids, and aggressive diuresis, and she continued the pregnancy. DISCUSSION: Pulmonary arterial hypertension is associated with right heart failure and is currently classified as modified World Health Organization class IV (pregnancy contraindicated). However, group 5 pHTN may be managed safely during pregnancy. TAKE-HOME MESSAGE: This case highlights that group 5 pHTN has a different cardiac risk profile compared with group 1 pulmonary arterial hypertension, and right heart catheterization was instrumental in stratifying this risk and counseling the patient.