Chapter 17-10: Pulmonary Hypertension

TEXTBOOK PRESENTATION

Patients commonly complain of long-standing dyspnea that progresses over months or years. Syncope, exertional chest pain, and edema occur with more severe PH and impaired right heart function.

DISEASE HIGHLIGHTS

1. Definition

   1. The normal mean pulmonary artery pressure (PAP) is 14 mm Hg.

   2. Table 17-7 outlines the clinical classification of PH.

   3. PH is defined as a mean PAP ≥ 25 mm Hg as assessed by right heart catheterization.

2. Epidemiology

   1. The prevalence of Group 1 PAH is 15 cases/million (about 3% of patients with PH); approximately one-half of these are idiopathic, heritable, or drug related

   2. Left heart disease is the etiology of PH in about 65% of cases; up to 83% of patients with HF with preserved ejection fraction have PH.

   3. Over 50% of patients with advanced chronic obstructive pulmonary disease have PH, as do 32–39% of patients with interstitial lung disease.

   4. Chronic thromboembolic disease is the etiology in 0.5–2% of patients with PH.

EVIDENCE-BASED DIAGNOSIS

1. History

   1. Initial symptoms are nonspecific and are usually related to right ventricular dysfunction, including dyspnea, fatigue, weakness, chest pain, and syncope.

   2. Less common symptoms include dry cough and exercise-induced nausea and vomiting.

2. Physical exam

   1. Characteristic findings include the following:

      1. An accentuated pulmonary component of S₂

      2. A sustained left lower parasternal movement

      3. Increased jugular a and v waves

      4. A tricuspid regurgitation murmur

      5. Ascites

      6. Elevated jugular venous pressure

      7. Edema

   2. Overall, physical exam techniques have limited utility in diagnosing PH.

      1. Loud P2 on inspiration: LR+, 1.9; LR–, 0.8

      2. Among specialists, an S₄ heard on inspiration: LR+, 4.7; LR–, 0.9

3. ECG

   1. Expected findings include right axis deviation, right ventricular hypertrophy, and P-pulmonale pattern (right atrial enlargement).

   2. Not sensitive or specific enough to diagnosis PH

   3. For right ventricular hypertrophy: sensitivity, 55%; specificity, 70%; LR+, 1.83; LR–, 0.64

4. Chest film

   1. Expected findings include enlargement of pulmonary arteries and right ventricular enlargement.

   2. Not sensitive or specific enough to diagnose PH (sensitivity, 46%; specificity, 63%; LR+, 1.24; LR–, 0.85)

5. Transthoracic echocardiogram is the best first diagnostic test.

   1. Echocardiogram estimates often correlate fairly well with invasively determined ...