Common and Severe Complications of Sickle Cell Disease
A team of scientists with the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health has found that a hormone detected in a simple blood test can identify patients with sickle cell disease who have developed a life-threatening complication called pulmonary hypertension. The team has also found that the same hormone is a clear predictor of death in adult sickle cell patients.
The hormone, called brain natriuretic peptide or BNP, is released
by the heart ventricles and helps predict death in heart failure patients. The
new study is published in the July 19 issue of the Journal of the American
“This is an important leap forward in research on sickle cell
disease,” said NHLBI Director Elizabeth G. Nabel, M.D. “Having a marker in the blood that will not only help identify sickle cell patients with this deadly complication but also predict those at the highest risk — will aid in the care and treatment of these patients.”
Sickle cell anemia is one of the most common genetic blood disorders in the United States. About 30 percent of sickle cell patients have pulmonary hypertension. In this condition, there is constant high blood pressure in the pulmonary arteries that supply the lungs. This pressure leads to narrowed arteries, causing the heart to work harder to pump blood.
Pulmonary hypertension often leads to heart failure and it is a major risk factor for death in adults with sickle cell disease. Currently, echocardiograms and other heart tests are used to diagnose pulmonary hypertension, but there has not been a blood test to help detect the condition.
Previous research has found that in patients with pulmonary hypertension, higher levels of BNP are associated with greater pressure in the pulmonary arteries. NHLBI researchers theorized that BNP levels might also correlate with the severity of pulmonary hypertension and risk of death in sickle cell patients.
Lead scientist Roberto Machado, M.D., an investigator with NHLBI’s
Vascular Medicine Branch, and colleagues measured BNP levels in 230 patients with sickle cell disease enrolled in the NIH Pulmonary Hypertension Screening Study between 2001 and 2005. In order to confirm a diagnosis of pulmonary hypertension, the patients were given echocardiograms and other measurements of heart function. BNP levels were also measured in 45 healthy black controls, since the disease is more prevalent in blacks.
The scientists found that high blood levels of BNP — greater than 160 pg/mL — in these patients independently predicted mortality, increasing the risk of death by as high as fivefold.
The team also found that BNP levels could help identify the patients with pulmonary hypertension. NIH study patients who had a BNP of 160 pg/mL or higher had a 78 percent chance of having pulmonary hypertension
identified by echocardiogram.
“We now have another tool to help diagnose pulmonary hypertension,” Machado said. “There is tremendous value in diagnosing this deadly complication early and accurately so we can aggressively treat the complication and try to improve the patient’s outcome.”
To validate and confirm the findings, the team then measured BNP
levels in 121 stored blood samples from patients who had been enrolled in a
sickle cell drug treatment study, the Multicenter Study of Hydroxyurea in Sickle Cell Anemia (MSH) Follow-up Study which began in 1996. These patients came from major sickle cell centers around the United States and at the time of enrollment it was not known that pulmonary hypertension was a common complication of sickle cell disease.
Thirty percent of patients in the MSH study had a BNP level
greater than 160 pg/ml, consistent with a diagnosis of pulmonary hypertension. Most importantly, these patients had a threefold increased risk of death compared with patients without pulmonary hypertension.
“The MSH analysis validated the connection between high BNP blood
levels, pulmonary hypertension and risk of death, found in the NIH study
patients,” said Mark Gladwin, M.D., chief of NHLBI’s Vascular Medicine Branch.
“It also revealed that almost a third of sickle patients in the 1996 MSH study had undiagnosed pulmonary hypertension. Perhaps the most intriguing finding, these data suggest that it is pulmonary hypertension — not painful crises or acute chest syndrome — that is the major risk factor for death in adults with sickle cell disease.” Acute chest syndrome is a life-threatening problem similar to pneumonia.
Sickle cell disease affects about 1 in 600 blacks and 1 in 1,000-1,400 Hispanic newborns every year. Patients with this disease have abnormal hemoglobin molecules in their red blood cells. The molecules damage the red cells, causing them to stick to blood vessel walls and resulting in pain, organ damage, and anemia.
With the development of new treatments for the symptoms and
complications of sickle cell disease, patient survival has improved in recent
Machado is optimistic regarding the future outlook for sickle cell
disease. “Based on these findings and other studies showing that pulmonary hypertension is a major risk factor for death in adult patients with sickle cell disease, there is great benefit to screening sickle cell patients with both echocardiography and blood BNP. By combining these tests, we hope to identify patients who can be treated more intensely to improve the management of their disease and hopefully their survival,” he said.
Machado added that identifying these patients will bring them to the attention of scientists engaged in clinical trials of new treatments for the disease. He noted that NHLBI is currently participating in a multi-center study to test the safety and effectiveness of the drug bosentan in patients with sickle cell disease and pulmonary hypertension. An NHLBI-sponsored clinical trial studying the effects of sildenafil as a treatment for pulmonary
hypertension in sickle cell disease is expected to begin recruiting patients early in 2007.
For information on sickle cell disease: http://www.nhlbi.nih.gov/health/dci/Diseases/Sca/SCA_WhatIs.html.
For information on pulmonary hypertension: http://www.nhlbi.nih.gov/health/dci/Diseases/pah/pah_what.html.
Part of the National Institutes of Health, the National Heart, Lung, and Blood Institute (NHLBI) plans, conducts, and supports research related
to the causes, prevention, diagnosis, and treatment of heart, blood vessel,
lung, and blood diseases; and sleep disorders. The Institute also administers national health education campaigns on women and heart disease, healthy weight for children, and other topics. NHLBI press releases and other materials are available online at: www.nhlbi.nih.gov.
The National Institutes of Health (NIH) — The Nation’s Medical Research Agency — includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services.
Goverment Medical Panel Says No To Prostate Cancer Screening
(BlackDoctor.org) — According to a government panel, the PSA blood tests that check for prostate cancer do more harm than good and healthy men should no longer receive them as part of routine cancer screening.
The recommendation by the U.S. Preventive Services Task Force will not be a surprise to cancer specialists…contrary to the controversial recommendations that the same panel made regarding breast cancer screening in 2009.
No major medical group recommends routine PSAs, and the government panel’s guidelines had long advised men over 75 to forgo them. The new recommendation extends that do-not-screen advice to healthy men of all ages.
Yet, the vast majority of men over 50 have had at least one PSA blood test. The assumption is that finding cancer early is always a good thing.
Not so, said Dr. Virginia Moyer of the Baylor College of Medicine, who heads the task force.
“We have put a huge amount of time, effort and energy into PSA screening and that time, effort and energy, that passion, should be going into finding a better test instead of using a test that doesn’t work,” Moyer told The Associated Press late Thursday.
Too much PSA, or prostate-specific antigen, in the blood only sometimes signals prostate cancer is brewing. It also can mean a benign enlarged prostate or an infection. Worse, screening often detects small tumors that will prove too slow-growing to be deadly. And there’s no sure way to tell in advance who needs aggressive therapy.
The task force analyzed all the previous research on this subject, including five major studies, to evaluate whether routine screening reduces deaths from prostate cancer. The conclusion: There’s little if any mortality benefit.
But there is harm from routine screening: impotence, incontinence, infections, even death that can come from the biopsies, surgery and radiation, Moyer said. One study estimated 2 of every 5 men whose prostate cancer was caught through a PSA test had tumors too slow-growing to ever be a threat.
Yet Moyer said 30 percent of men who are treated for PSA-discovered prostate cancer suffer significant side effects, sometimes death, from the resulting treatment. About a third of men ages 40 to 60 have brewing prostate cancer but “the huge majority of them will never know it in their lifetime if they are not screened,” she added.
The task force previously had considered the evidence for or against PSA screening inconclusive. The new recommendation says not to routinely screen. That recommendation is a draft that is open for public comment beginning next week.
“We have been long concerned, and it has been apparent for some years, that some supporters of prostate cancer screening have overstated, exaggerated and in some cases misled men about the evidence supporting its effectiveness,” said Dr. Otis Brawley of the American Cancer Society in a statement. “We need balanced, truthful information to be made widely available to physicians and patients when making important health decisions.”
The society had not seen the new recommendation yet, but has long advised men to consider the pros and cons of PSA screening before deciding on their own.
Moyer said the recommendation only means that doctors shouldn’t bring up the option for healthy men. If a man asks for a PSA test and wants it after being informed of the evidence, he should receive it, she said. Likewise, it’s appropriate to use PSA tests to examine a man with possible prostate symptoms.