Pulmonary Hypertension

Today we discussed a case of newly diagnosed Pulmonary Hypertension in a young woman.

Pulmonary Hypertension (PH) is defined as a Pulmonary Arterial Pressure over 25 mmHg at rest (normal 12-16 mmHg).

Patients often present with months or years of gradually progressive symptoms, such as shortness of breath, fatigue, cough, angina, peripheral edema, and rarely hemoptysis.

Cardiovascular examination often reveals a loud, palpable P2, a split S2, and an RV heave.

There are multiple causes of PH, but all result in increased pressures within the pulmonary vasculature, either due to vasoconstriction of the blood vessels, obstruction by way of a mass or pulmonary emboli, or fibrosis within the lung parenchyma related to systemic illnesses. In order to overcome this increased pulmonary pressure, the heart then is required to create elevated right-sided pressures in the heart. In turn, this leads to RV hypertrophy and potentially RV failure.

PH is classified according to the WHO into 5 major categories:
Class I: Pulmonary Arterial Hypertension

Idiopathic

Familial

Connective Tissue Disorders, HIV, Drugs, Toxins, Congenital Left-to-Right Shunts, etc.
Class II: PH with Left Heart Disease

Left Atrial or Ventricular Heart Disease

Left-sided Valvular Heart Disease
Class III: PH Associated with Lung Diseases or Chronic Hypoxia

COPD, Interstitial Lung Disease, Sleep Disordered Breathing, etc.
Class IV: PH Due to Chronic Thrombotic and/or Embolic Disease

Thromboembolic obstruction of the proximal or distal pulmonary arteries

Nonthrombotic obstruction of the pulmonary arteries (ie: tumor, foreign body, etc.)
Class V: Miscellaneous causes

Sarcoidosis, Lymphangiomatosis, etc.

Given the numerous potential causes for PH, any patient with suspected PH requires significant investigations to diagnose PH and then to determine the etiology of their PH. This includes basic blood work (looking for evidence of polycythemia), an ECG (evidence of RAE or RVH), a CXR, and echocardiogram, a CT Chest, a V/Q scan (to detect chronic thromboembolic disease), a 6-minute walk test, and a Right-Heart Catheterization to name a few!

These patients are managed by the multidisciplinary PH team where the goals of treatment include symptom management, improving quality of life, and prolonging survival, which often requires a lung or heart-lung transplant.

Here is a review article on the mechanisms of PH, and here are the 2009 American College of Cardiology Consensus Guidelines for PH.