People with sickle cell disease should be screened for pulmonary hypertension
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《英国医生杂志》
Pulmonary hypertension has been identified as a major risk factor for death in adults with sickle cell disease, and all people with the disease should be screened for this complication, a new study says.
Almost a third of adult patients with sickle cell disease who were screened with Doppler echocardiography were found to have moderate to severe pulmonary hypertension that had not previously been detected (New England Journal of Medicine 2004;350:886-95).
The researchers assessed pulmonary artery systolic pressure in 195 consecutive patients (82 men and 113 women with a mean (SD) age of 36 (12) years). Patients were followed for a mean of 18 months.
Pulmonary hypertension, prospectively defined as a tricuspid regurgitant jet velocity of 3 2.5 m/s, occurred in 62 (32%) patients. The risk of death in these patients was significantly higher than in patients who had a tricuspid regurgitant jet velocity <2.5 m/s (rate ratio 10.1 (95% confidence interval 2.2 to 47.0; P<0.001)). After the 18 month follow up period, during which five patients left the study, 12 of the 62 participants with pulmonary hypertension died. Only two of the 128 participants without hypertension as defined in the study died.
The researchers, from the US National Institutes of Health, Bethesda, Maryland, and the Howard University Center for Sickle Cell Disease, Washington, DC, said that their results confirm earlier indications from studies of patients?records that pulmonary hypertension is present in 20% to 40% of patients with sickle cell disease and that it poses a major threat of death. The researchers said the findings were so striking that all patients with sickle cell disease should be regularly screened.
In addition, they said, patients with mild to moderate pulmonary hypertension should have the condition treated, because the increased risk of death seems to be high even in less severe cases. "In sickle cell patients this appears to be the number one predictor of sudden death syndrome," said the study抯 lead author, Dr Mark Gladwin of the institutes?Magnuson Clinical Center. "This is when a patient who appears to be doing well suddenly falls ill and dies."
The researchers postulated that the cause of the problem was excess free haemoglobin in the blood resulting from the breakdown of red blood cells. This haemoglobin scavenges nitric oxide, a chemical that dilates blood vessels, and another product of red blood cells, arginase, which blocks the activity of arginine, a chemical that is crucial for making nitric oxide.
Many patients with sickle cell disease take the drug hydroxycarbamide (hydroxyurea), which helps produce a healthier form of haemoglobin and enhances the availability of nitric oxide. Other treatments include blood transfusions and inhaled nitric oxide. The researchers also suggested that doctors enrol patients with sickle cell disease in trials involving drugs that can increase concentrations of nitric oxide, such as oral arginine, and drugs approved to treat primary pulmonary hypertension, such as epoprostenol (prostacyclin) and calcium channel blockers.(New York Scott Gottlieb)
Almost a third of adult patients with sickle cell disease who were screened with Doppler echocardiography were found to have moderate to severe pulmonary hypertension that had not previously been detected (New England Journal of Medicine 2004;350:886-95).
The researchers assessed pulmonary artery systolic pressure in 195 consecutive patients (82 men and 113 women with a mean (SD) age of 36 (12) years). Patients were followed for a mean of 18 months.
Pulmonary hypertension, prospectively defined as a tricuspid regurgitant jet velocity of 3 2.5 m/s, occurred in 62 (32%) patients. The risk of death in these patients was significantly higher than in patients who had a tricuspid regurgitant jet velocity <2.5 m/s (rate ratio 10.1 (95% confidence interval 2.2 to 47.0; P<0.001)). After the 18 month follow up period, during which five patients left the study, 12 of the 62 participants with pulmonary hypertension died. Only two of the 128 participants without hypertension as defined in the study died.
The researchers, from the US National Institutes of Health, Bethesda, Maryland, and the Howard University Center for Sickle Cell Disease, Washington, DC, said that their results confirm earlier indications from studies of patients?records that pulmonary hypertension is present in 20% to 40% of patients with sickle cell disease and that it poses a major threat of death. The researchers said the findings were so striking that all patients with sickle cell disease should be regularly screened.
In addition, they said, patients with mild to moderate pulmonary hypertension should have the condition treated, because the increased risk of death seems to be high even in less severe cases. "In sickle cell patients this appears to be the number one predictor of sudden death syndrome," said the study抯 lead author, Dr Mark Gladwin of the institutes?Magnuson Clinical Center. "This is when a patient who appears to be doing well suddenly falls ill and dies."
The researchers postulated that the cause of the problem was excess free haemoglobin in the blood resulting from the breakdown of red blood cells. This haemoglobin scavenges nitric oxide, a chemical that dilates blood vessels, and another product of red blood cells, arginase, which blocks the activity of arginine, a chemical that is crucial for making nitric oxide.
Many patients with sickle cell disease take the drug hydroxycarbamide (hydroxyurea), which helps produce a healthier form of haemoglobin and enhances the availability of nitric oxide. Other treatments include blood transfusions and inhaled nitric oxide. The researchers also suggested that doctors enrol patients with sickle cell disease in trials involving drugs that can increase concentrations of nitric oxide, such as oral arginine, and drugs approved to treat primary pulmonary hypertension, such as epoprostenol (prostacyclin) and calcium channel blockers.(New York Scott Gottlieb)