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Other disorders of heart, lungs, and pulmonary vasculature must be considered (Fig. 127-1). Lung function studies will identify chronic pulmonary disease causing pulmonary hypertension and cor pulmonale. Interstitial diseases (PFTs, CT scan) and hypoxic pulmonary hypertension (ABGs, SaO2) should be excluded. Perfusion lung scan should be considered to exclude chronic pulmonary embolism (PE). Cardiovascular disorders that may present similarly and need to be excluded include PA and pulmonic valve stenosis, ventricular and atrial shunts with secondary pulmonary vascular disease (Eisenmenger syndrome), and clinically silent mitral stenosis.

Treatment: Pulmonary Arterial Hypertension

Limit physical activities, use diuretics for peripheral edema, O2 supplementation if PO2 reduced, and chronic warfarin anticoagulation (target INR = 2.0-3.0).

If short-acting vasodilators are beneficial during acute testing in catheterization laboratory, pt may benefit from high-dose calcium channel blocker (e.g., nifedipine, up to 240 mg/d, or amlodipine up to 20 mg/d); must monitor for hypotension or worsening of right heart failure during such therapy.

Additional approved therapies for PAH include:

  1. Endothelin receptor antagonists: bosentan (62.5 mg PO bid × 1 month, then 125 mg PO bid) and ambrisentan (5-10 mg daily) significantly improve exercise tolerance. Hepatic transaminases should be monitored. Bosentan is contraindicated in pts taking cyclosporine (which greatly increases bosentan plasma levels) or glyburide (combination is associated with increased hepatic transaminases).
  2. Phosphodiesterase-5 inhibitors: sildenafil (20-80 mg PO tid) and tadalafil (40 mg daily) also improve exercise tolerance in PAH. Do not prescribe concurrently with nitrates; the combination could result in marked hypotension.
  3. Prostaglandins (iloprost by inhalation, epoprostenol by continuous IV infusion, and treprostinil by IV, SC, or inhalation routes) improve symptoms, exercise tolerance, and, in the case of epoprostenol, survival. The most common side effect is flushing.
  4. The oral soluble guanylyl cyclase stimulator riociguat has been shown to improve exertional capacity in pts with PAH.

For selected pts with persistent right heart failure, lung transplantation may be considered.

For a more detailed discussion, see Waxman AB, Loscalzo J: Pulmonary Hypertension, Chap. 304, p. 1655, in HPIM-19.

Outline ⬆

Section 8. Cardiology