Study Reveals Risk Factors for Pulmonary Hypertension in Sickle Cell Patients

Study Reveals Risk Factors for Pulmonary Hypertension in Sickle Cell Patients

A study in PLoS One entitled “Risk Factors of Pulmonary Hypertension in Brazilian Patients with Sickle Cell Anemia” published September 3, 2015 and authored by Clarisse Lopes de Castro Lobo, et. al, explored the possible risk factors for pulmonary hypertension in individuals who already have sickle cell anemia (SCA). The participants in the study were between the ages of 16 and 60.  The idea behind the study was to identify those SCA patients who were at the greatest risk for developing pulmonary hypertension so that intervention could be initiated  more quickly.

The study analyzed 125 patients with sickle cell disease who, by virtue of the disease’s pathology, are at a higher risk for pulmonary hypertension. People with sickle cell disease have an autosomal recessive blood disease characterized by an abnormal hemoglobin S that forms a sickle shape under low oxygen tension situations.

Sickle cell patients that have pulmonary hypertension are defined as having a resting mean pulmonary arterial pressure of greater than 25 mm Hg, as measured by performing right heart catheterization. About six percent of sickle cell disorder patients develop some type of pulmonary hypertension.

The study was conducted in Brazil, where there is a long waiting list for right catheterization. The risk of sickle cell disease is high in Brazil, with about 25,000 to 30,000 people with the disease. The researchers wanted to identify risk factors for developing pulmonary hypertension so that the right people get on the short-list for right heart catheterization and can be properly treated for the disease.

The tricuspid regurgitant jet velocity (TRJV) as detected on Doppler Electrocardiograph was used to diagnose people at risk for pulmonary hypertension, however, the test is not considered the gold standard for diagnosing patients with pulmonary hypertension. A total of 34 percent of patients had an abnormal TRJV, while 66 percent of patients had a normal TRJV.

The researchers then compared various factors that predicted pulmonary hypertension. They discovered that participants who had an abnormal TRJV were much older, had a higher degree of anemia, much higher LDH levels, a creatinine level greater than 1.o,  and a higher reticulocyte count when compared to those who had a normal TRJV.  The cut off for being at an increased age risk for the disease was 32 years of age.

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Naturally, the patients with an abnormal TRJV had a higher risk of death when compared to those who had a normal TRJV, with a total of 9 patients dying during the 15 month study. Of those who died, 7 had an abnormal TRJV. The patients who passed away generally died of acute chest syndrome, a common complication of pulmonary hypertension.

In summary, it was found that sickle cell patients older than age 32 years who had an abnormal TRJV, a high level of LDH, an elevated creatinine level, and severe degrees of anemia were at a higher risk of having pulmonary hypertension. These are patients who according to the researchers should be short-listed to have a right heart catheterization so that treatment can be initiated.

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