|
Diagnosis of Pulmonary Hypertension:
History and a careful physical examination are paramount to the diagnosis of pulmonary hypertension. Particular attention should be given to previous medical conditions, drug use (legal and illegal) and family history. In addition, all systems should be carefully reviewed. Commonly, suspicion is increased by the presence of increasing dyspnea on exertion in a patient with a known cause of pulmonary hypertension.
Electrocardiogram demonstrating the changes of right ventricular hypertrophy (long arrow) with strain in a patient with primary pulmonary hypertension and Right axis deviation
Chest Xray shows right ventricular hypertrophy.
Patient should undergo two-dimensional echocardiography with Doppler flow studies. Echocardiography is the most useful imaging modality for detecting pulmonary hypertension and excluding underlying cardiac disease. Confirmation of pulmonary hypertension is based on identification of tricuspid regurgitation. The addition of mean right atrial pressure to the peak tricuspid jet velocity gives an accurate noninvasive estimate of peak pulmonary pressure. Right ventricular dilatation and hypertrophy are late findings.
Arterial blood gas analysis should be performed to exclude hypoxia and acidosis as contributors to pulmonary hypertension.
Pulmonary function tests are necessary to establish airflow obstruction or restrictive pulmonary pathology. Computed tomographic (CT) scanning of the chest with high-resolution images is useful for excluding occult interstitial lung disease and mediastinal fibrosis when the pulmonary function tests and chest radiograph are nondiagnostic.
Cardiac catheterization should be performed in patients with unexplained pulmonary hypertension, and remains the gold standard for its diagnosis and quantification. Catheterization is particularly useful in diagnosing occult shunts, congenital heart disease and distal pulmonary artery stenosis.
Treatment of Pulmonary Hypertension:
Treatment goals are
-
dilate pulmonary vessels by calcium channel blockers, prostacyclins Nitric oxide (investigational)
-
Decrease thickening of blood by warferin
-
Decrease preload on heart by diuretics and decrease salt intake
-
Increase oxygen supply to lungs
-
Prevention and treatment of respiratory infection by antibiotics
-
Increase cardiac output by inotropic drugs
-
Treat cause of secondary Pulmonary hypertension.
Calcium channel blockers may alleviate pulmonary vasoconstriction and prolong life in about 20 percent of patients with primary pulmonary hypertension.
Epoprostenol (Flolan), or prostacyclin, is the single most important advance in the treatment of primary pulmonary hypertension. This potent, short-acting vasodilator and inhibitor of platelet aggregation is produced by vascular endothelium. In one study,continuous intravenous infusion of epoprostenol improved exercise capacity, quality of life, hemodynamics and long-term survival in patients with class III or IV functionAlthough the delivery system for continuous infusion is complex, most patients are able to learn how to prepare and infuse the drug.
Chronic anticoagulation with warfarin (Marivan) is recommended to prevent thrombosis and has been shown to prolong life in patients with primary pulmonary hypertension.1 Patients with this condition are prone to thromboembolism because of sluggish pulmonary blood flow, dilated right heart chambers, venous insufficiency and relative physical inactivity. Maintaining an INR of 1.5 to 2.0 is recommended.
Because hypoxia is a potent pulmonary vasoconstrictor, it is critical to identify and reverse hypoxemia. Low-flow supplemental oxygen therapy prolongs survival in hypoxemic patients. Failure to recognize and correct hypoxemia may be the error most frequently made in the treatment of patients with pulmonary hypertension. Pt should have oxygen cylinder with them at high altitudes.
A low-salt diet and judicious use of diuretics can be helpful in reducing volume overload in patients with pulmonary hypertension and right ventricular failure. Because the right heart is dependent on preload, care should be taken to avoid excessive diuresis and further reduction of cardiac output.
In patients with secondary pulmonary hypertension, management is directed at early recognition and treatment of the underlying disease (while it is still potentially reversible). For instance, left ventricular dysfunction should be treated with afterload-reducing agents, digoxin and diuretics. Surgery to correct structural cardiac and pulmonary anomalies can also be effective, and thromboendarterectomy for accessible chronic thromboemboli is potentially curative. Improvement or resolution of pulmonary hypertension may occur after the discontinuation of anorectic agents, although resolution is not typical. Pulmonary hypertension associated with interstitial lung disease may respond to corticosteroids or other immunosuppressive agents.
Lung Transplantation
Primary pulmonary hypertension is usually progressive and ultimately fatal. Lung transplantation is an option in some patients younger than 65 years who have pulmonary hypertension that does not respond to medical management. According to a 1997 U.S. transplant registry report, lung transplant recipients with primary pulmonary hypertension had survival rates of 73 percent at one year, 55 percent at three years and 45 percent at five years. The immediate reduction in pulmonary artery pressure is associated with an improvement in right ventricular function. Recurrence of primary pulmonary hypertension after lung transplantation has not been reported.
| 
