What is Pulmonary Hypertension (PH)?
Pulmonary hypertension is a disease that causes the blood vessels in the lungs to have unusually high pressure. This high pressure in the pulmonary arteries results in the heart being unable to pump against the resistance of the blood pressure in the lungs. The heart needs to circulate the blood through the lungs: the right side of the heart pumps blood into the lungs to become oxygenated, the left side of the heart sends the oxygenated blood throughout the body.
The resistance caused by the hypertesnion- high pressure in the blood vessels of the lungs eventually damages the heart's right ventricle. The right ventricle will change in shape and size until it can no longer pump. The patient will suffer heart failure and die. In 1998, 2404 deaths were attributed to Primary Pulmonary Hypertension.
What Causes PH?
Doctors are not sure what causes Pulmonary Hypertension, however there are several identifying factors that are related:
1) Pulmonary Hypertension is often the result of another disease that affects the body such as heart disease, lung disease or liver disease, as well as HIV infection or systemic connective tissue disease (such as scleroderma). These conditions give rise to "Pulmonary Hypertension," or " Secondary Pulmonary Hypertension" (SPH) however if the cause cannot be pinpointed the diease is referred to as "Primary Pulmonary Hypertension." (PPH)
2) Primary Pulmonary Hypertension has been commonly linked to the use of appetite suppressants Fen-Phen. The results of a study published in April 2000 observed that of 579 patients diagnosed with pulmonary hypertension at 12 medical centers nationwide concluded that as many as 205 people who had primary pulmonary hypertension may have been affected by diet drugs. See article below >>
3) Doctors also believe the diease may be rooted in genetics. PPH affects more woman than men and an estimated 6-10% of PPH cases run in consecutive family generations. Scientists at Vanderbuildt have identified a specific chromosome that is related to PPH, but do not know the exact type of defect it is. The search for this defect is underway and may soon lead to a cure.
Primary pulmonary hypertension linked to appetite suppressants Fen-Phen
The diet drug fenfluramine, known widely as the "fen" in the drug fen-phen, appears to be behind increased rates of a serious heart condition known as primary pulmonary hypertension, according to new research.
Fen-phen was pulled from the market in 1997 amid concerns that it could cause serious heart valve problems.
The new research involves an even more serious condition that in many cases is life-threatening. Primary pulmonary hypertension (PPH) is a blood vessel disorder of the lung in which the pressure in the pulmonary artery rises above normal levels.
"It's a very rare disease, that tends to particularly affect women in their 30s. After diagnosis, patients are typically dead within two years," says Dr. Sean Gaine, director of the pulmonary hypertension center at Johns Hopkins Medical Center in Baltimore.
By removing fen-phen from the market, the FDA may well have aborted an epidemic of the hypertension problem in the United States, say researchers at Rush Medical College in Chicago.
Their findings are based on a multi-center study called the Surveillance of North American Pulmonary Hypertension (SNAP), which is published in a recent issue of the journal Chest.
The study included observations of 579 patients diagnosed with pulmonary hypertension at 12 medical centers nationwide. Of the subjects, 205 had primary pulmonary hypertension, which means there was no known cause for their problem. Figures on those patients were compared with 367 patients who had what's known as secondary primary hypertension, meaning a cause, such as a specific health problem, had been established.
The researchers report that 16 percent of the patients with the primary form had used fenfluramines. Among those with the secondary type, 11 percent had used the drugs.
"The SNAP results show a clear association between the use of fenfluramines and the diagnosis of PPH as compared to those with SPH," write the authors.
But even the fact that 11 percent of those with the secondary type used the drugs raises concern, they say. "Although the unexpectedly high reported rate of anorexigen (appetite suppressants) use in SPH patients could be an artifact, it could also point to wider concern," they write.
The concern, they describe, is that the causes attributed to the patients with secondary pulmonary hypertension may have been exacerbated by the use of the diet drugs.
While previous studies had linked fenfluramine with increased rates of pulmonary hypertension, this was the first study in the United States to make a clear association.
Researchers say there had always been concern about the drugs' potential for causing primary pulmonary hypertension, and their suspicions were fueled when cases of the disease began to appear in higher numbers than usual as soon as fenfluramine and the other appetite-suppressants phentermine (the latter referral in fen-phen) and dexfenfluramine hit the market.
But at the same time, heart valve problems of a somewhat less serious nature also began appearing in higher numbers and wound up being responsible for the removal of the drugs from the market.
"We had been concerned about PPH links to these drugs for years, but that was lost amid all the scuffle about the heart valve disease," Gaine says. "That came out of the blue. No one was expecting it."
The fen-phen issue has remained controversial, with studies offering conflicting evidence on the extent of heart valve problems that the drug truly presented.
But Gaine says that even without the heart valve issue, the findings of the SNAP study offer much more alarming evidence of the drug's danger.
"There are two issues here because there's a big difference between the heart valve problems and pulmonary hypertension," he says. "The heart valve problem is bad, but at least it's something there's a cure for. You can replace the valve if you get it in time and so forth, but there's no cure for pulmonary hypertension."
He adds, "There are some very involved treatments that can improve life expectancy, or we can do lung transplants, but it's still very tricky to treat."
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