WASHINGTON - High blood pressure in the lungs has been identified as a major risk factor for death in adults with sickle cell disease, and all patients with the disease should be screened for it, according to a study to be published today.
Almost one-third of adult sickle cell patients who were screened with ultrasound were found to have moderate to severe high blood pressure in the lungs that had not previously been detected, the study found.
The results from the tests confirm earlier suggestions from studies of patient records that pulmonary hypertension is present in 20 percent to 40 percent of sickle cell patients and poses a major threat of death, the researchers said in their paper, which appears in The New England Journal of Medicine.
The researchers, from the National Institutes of Health and the Howard University Center for Sickle Cell Disease, said the findings were so striking that all patients with sickle cell should be regularly screened.
They also said patients with even mild to moderate pulmonary hypertension should have the disorder treated because the added risk of death appears high even in less severe cases.
"In sickle cell patients, this appears to be the No. 1 predictor of sudden death syndrome," said the study's lead author, Dr. Mark T. Gladwin of the health institutes' Magnuson Clinical Center. "Even people with mild pulmonary hypertension caused by sickle cell disease are at risk of sudden death."
Pulmonary hypertension is high blood pressure in the arteries that supply the lungs, a disorder that results in the vessels' narrowing and their walls' thickening to restrict blood flow. When this disorder is caused by an underlying disease, such as sickle cell, it is known as secondary pulmonary hypertension.
In the new study, researchers followed 195 sickle cell patients, 82 men and 113 women, for two years. The average age was 37.
The researchers found that 32 percent of the patients had mild to severe pulmonary hypertension. At the end of 18 months, 20 percent of the 62 participants with pulmonary hypertension died. Of the 128 participants without demonstrated hypertension, only two died. Five patients left during the follow-up.
Dr. Oswaldo Castro of Howard University, an author of the study, said the research proved that earlier studies had not exaggerated the risk of a sickle cell-pulmonary hypertension link: "We now know this situation is real and can take steps to do something about it."
Sickle cell disease is an inherited blood disorder that affects hemoglobin, the oxygen-carrying protein of red blood cells.
Screening might not immediately benefit patients but could lead to the discovery of effective treatments that have so far eluded scientists, some doctors said.
Dr. Chi Dang, a hemotologist with the Johns Hopkins School of Medicine, said the drug hydroxyurea often helps to ease the extreme attacks of bone and muscle pain that afflict many patients. But it does not prevent long-term complications of sickle cell disease, such as pulmonary hypertension.
"The problem in the past is that there hasn't been effective therapies," said Dang. "Now, you can screen patients and encourage them to contribute to clinical trials."
Sun staff writer Jonathan Bor contributed to this article.