Dr. Rich has a career interest in understanding the causes and treatments of pulmonary hypertension. He was principle investigator for the NIH Registry on Primary Pulmonary Hypertension, the first of its kind, and has been the leader of the largest clinical center in the USA for evaluating and treating patients with pulmonary hypertension since 1980. Dr. Rich has conducted pioneering research on the molecular mechanisms, epidemiology, clinical presentation, natural history and treatments of the disease. This knowledge has lead to the discovery of more effective treatments for pulmonary hypertension, including the use of medicines like anticoagulants, calcium channel blockers, and prostacyclins. His pioneering research has led to a greater understanding of all types of pulmonary hypertension.

Dr. Rich is currently involved with novel drug and device development to treat advanced pulmonary hypertension and right heart failure. This includes disease modifying drugs for pulmonary arterial hypertension, a first-in-man for pulmonary hypertension associated with heart failure with preserved function, and a durable right ventricular assist device. In addition, he is a collaborator with the World Health Organization Global Burden of Disease initiative and the newly initiated pulmonary hypertension project.

He has expanded the Pulmonary Vascular Disease Program at Northwestern to now offer every approved intervention for patients, including every approved medicine, interventional procedures, surgical pulmonary endarterectomy, and lung transplantation. He also has created an alliance with the Pulmonary Hypertension Program at Lurie Children's Hospital to now offer clinical services to any patient with pulmonary hypertension of any age.