Secondary pulmonary hypertension is a disorder of the blood vessels in the lungs. It usually is the result of other lung diseases or related diseases in other organs. Affected individuals have high blood pressure (hypertension) of the main artery of the lungs (pulmonary artery). The disorder is characterized by breathing difficulties, especially after exertion.
Secondary pulmonary hypertension is characterized by symptoms of breathlessness or shortness of breath upon exertion. Additional symptoms may include anxiety, rapid breathing, chest pain, and in extreme cases heart failure. Swelling (edema) of the legs may occur in some cases. Measurements of right and left descending pulmonary artery diameter can provide a correct diagnosis in 98% of individuals with suspected pulmonary hypertension. In the right lung artery a diameter over 16.7mm and in the left lung artery a diameter of over 16.9mm, is an indication of excessively high lung pressure.
There can be a number of causes of secondary pulmonary hypertension. Lung (pulmonary) and heart (cardiac) disorders are the most common causes of secondary pulmonary hypertension. Blood clots in the pulmonary arteries, decrease in the size of blood vessels (pulmonary vasoconstriction), a form of scleroderma called CREST syndrome (characterized by calcenosis, Raynaud’s phenomenon, esophageal dysfunction, sclerodactylia and telangiectosis) may cause pulmonary hypertension. Other causes may be living at high altitude, thickening of the blood, and portal hypertension. Secondary pulmonary hypertension may also occur for unknown reasons.
In August 1996, the Food and Drug Administration (FDA) evaluated data from a report of the International Primary Pulmonary Hypertension Study (IPPHS). The study examined the relationship between appetite-suppressant drugs (dexfenfluramine [Redux]) and primary pulmonary hypertension. Preliminary findings indicate that the risk of primary pulmonary hypertension in individuals using appetite-suppressant drugs for three months or longer to be about nine times higher than non-users. The final IPPHS report estimated that the risk of this disorder is about 23 times higher in individuals who use appetite-suppressants for three months or longer. Additional findings suggest an association with the combination of the appetite-suppressant drugs, fenfluramine and phentermine, in the development of pulmonary hypertension. The FDA states that appetite-suppressant drugs should be administered only under careful medical supervision.
Additional News About FEN/PHEN
Based upon new evidence about significant side effects associated with the use of the diet drugs fenfluramine (Pondimin) or dexfenfluramine (Redux) in combination with phentermine (fen-phen or dexfen-phen), the FDA requested that the manufactures voluntarily withdraw fenfluramine and dexfenfluramine from the market. In July of this year, the Mayo Clinic reported a rare clustering of unusual cases of heart valve disease (e.g., leaky valves, backward flow of blood through the valve, etc.) in individuals who had taken these anti-obesity drug combinations. These patients were evaluated through an echocardiogram, a specialized imaging procedure that can test the functions of heart valves. A group of five physicians reported that about 30 percent of former fen/phen users who were evaluated had an abnormal echocardiogram. Though fen-phen and dexfen-phen were a popular diet drug combination, no studies were submitted to the FDA to demonstrate long-term safety or effectiveness of these drugs when taken together. Therefore, the manufacturers have withdrawn these drugs from the market and FDA has recommended that people who took the drugs should contact their physicians for heart examinations.
Secondary pulmonary hypertension is a disease that affects males and females in equal numbers. The frequency of secondary pulmonary hypertension in the general population is unknown.
Prior to treatment of secondary pulmonary hypertension, tests to confirm the diagnosis and degree of this disorder should be carried out. This may be done by a right-sided cardiac catheterization or use of echo-cardiography. After diagnosis, physical activity should be limited and any underlying causes such as: heart disease, clogged arteries or living at high altitude should be treated.
Drug therapy to treat pulmonary hypertension may include the use of drugs that cause widening of blood vessels (vasodilators) and lessen blood pressure. Types of vasodilators include hydralazine and nifedipine.
Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
Tollfree: (800) 411-1222
TTY: (866) 411-1010
For information about clinical trials sponsored by private sources, contact:
Pulmonary Hypertension Association. Pulmonary Hypertension: A Patient’s Survival Guide. 2nd Ed. PHAssociation. Silver Spring, MD.
Beers MH, Berkow R., eds. The Merck Manual, 17th ed. Whitehouse Station, NJ: Merck Research Laboratories; 1999:1703-04; 2142-43.
Nauser TD, Stites SW. Diagnosis and treatment of pulmonary hypertension. Am Fam Physician. 2001;63:1789-98.
Ivy D, Eels P. Diagnosis and treatment of pulmonary hypertension in the adolescent. Adolesc Med. 2001;12:79-93.
Ivy D. Diagnosis and treatment of severe pediatric pulmonary hypertension. Cardiol Rev. 2001;9:227-37.
Ricciardi MJ, Rubenfire M. How to manage secondary pulmonary hypertension. Postgrad Med. 1999;105:183-90; Quiz 229.
FROM THE INTERNET
Sharma S. Secondary Pulmonary Hypertension. Emedicine. 2003. Available at: http://www.emedicine.com/med/topic2946.htm Accessed on: July 5, 2004.