Pulmonary HTN

The main principles of treatment encompass:

• providing supplemental oxygen to help avoid hypoxemia, and to improve oxygenation,
• anticoagulation for the prevention of further pulmonary emboli, and
• vasodilatory therapy to reverse the vasoconstrictive component of pulmonary hypertension.

The goal of oxygen therapy (supplementation) is to maintain oxygen saturation over 90% at all times to attenuate hypoxic pulmonary vasoconstriction. Therefore, supplemental oxygen may be necessary during periods of exertion or at rest as well.

Long term Coumadin (warfarin) therapy has been shown to improve survival of the patients suffering from primary pulmonary hypertension . Prothrombin time needs to be monitored and the desirable level of anticoagulation is to keep the INR level between 2-3.

For the reversal of pulmonary vasoconstrictive component of pulmonary hypertension (if present) both calcium channel blockers and prostacyclines have been used with somewhat limited success. The goal of vasodilatory therapy is to reduce mean pulmonary artery pressures at least 20% below the pretreatment level, and to improve cardiac output without inducing systemic hypotension.

Of the calcium channel blockers both nifedipine and diltiazem have been used for long term oral treatment (they have lesser negative inotropic effects than other calcium channel blockers).

Unfortunately, only about 25-26% of the patients respond favorably to this treatment. Studies show that patients who respond favorably have a 5 year survival of 94% compared to 55% for dose who do not respond to calcium channel blockers .

 The usual doses of nifedipine range between 120-240 mg/day (sustained release formula), but doses as high as 900 mg/day of diltiazem have been used.

1. Arroliga, AC et al., in Chest Medicine, Essentials of Pulmonary and Critical Care Medicine, Eds: George, Light, Matthay and Matthay, Lippincott, William and Wilkins 2000, pp. 233-262
2. Rubin, LJ, NEJM, 1998, 336:111-117