Pulmonary hypertension, particularly pulmonary arterial hypertension (PAH), is often cited as a complication of sickle cell disease.
Characteristics of a classic case include the presence of pre-capillary pulmonary hypertension in the absence of left-sided heart disease, lung disease, or chronic thrombo embolism. Histopathology of small pulmonary arteries reveals proliferation of medial smooth-muscle cells and endothelial cells. In the updated classification of pulmonary hypertension, sickle cell disease (SCD) is included as a separate entity in the subgroup of PAH associated with identified diseases. Recent studies have revealed that the frequency of PAH in patients with SCD is 30%.
AdvertisementThe objective of a study recently published in the New England Journal of Medicine was to evaluate the prevalence of pulmonary hypertension (PH) in adult patients with sickle cell disease (SCD) and confirm it with the help of right heart catheterization. In these patients, SCD was initially suspected on the basis of Doppler echocardiography.
MethodsIn this prospective study, 398 outpatients (average age, 34 years) were recruited from referral centers for SCD in France. The study was also carried out in collaboration with the National Reference Center for Pulmonary Hypertension.
All patients included in the study were homozygous for hemoglobin S or had Sβ0 thalassemia. Only stable outpatients were included in the study.
Exclusion criteria included -
· Severe renal insufficiency,
· Severe liver disease
· Chronic restrictive lung disease.
The patients were subjected to Doppler echocardiography, with measurement of tricuspid-valve regurgitant jet velocity. Right heart catheterization was performed in 96 patients in whom pulmonary hypertension was suspected.
Pulmonary hypertension was defined as a mean pulmonary arterial pressure of a minimum of 25 mm Hg.
Follow up was carried on for three years from date of study. Details of death, if any, were carefully documented.
Results & ConclusionIn this study of adult patients with sickle cell disease, the prevalence of a tricuspid regurgitant jet velocity, of at least 2.5 m per second, on echocardiography was 27%. This rate of occurrence was consistent with other studies carried out thus far.
In contrast, pulmonary hypertension prevalence that was confirmed on right heart catheterization was only about 6%. Approximately half of these patients, with confirmed PH, had pre-capillary pulmonary hypertension.
Based on their samples, the study concludes that the prevalence of pulmonary hypertension as detected on initial echocardiography screening, and confirmed by right heart catheterization, was 6% and that echocardiography alone was not enough to detect pulmonary hypertension.
"A Hemodynamic Study of Pulmonary Hypertension in Sickle Cell Disease" Florence Parent, M.D., Dora Bachir, M.D., Jocelyn Inamo, M.D.,et al., N Engl J Med 2011; 365:44-53