The Sickle Cell-Pulmonary Hypertension Screening Study: ECHO Findings at Two-Years of Follow Up.

In a prospective study started in 2001 echocardiography (ECHO) was used to screen 195 unselected adult sickle cell patients for pulmonary hypertension (PHTN). The prevalence of PHTN [tricuspid regurgitant jet velocity (TRV) of 2.5 m/sec or higher, corresponding to a pulmonary artery systolic pressure (PAs) of at least 35 mm Hg] was 32 %. Markers of hemolysis (low Hb, and high reticulocytes and LDH) were associated with PHTN risk. Although the pulmonary pressures in sickle-related PHTN were not as high as in other forms of PHTN, they were predictive of short survival (

We now report the TRV results in 113 patients who had repeat ECHO exams at 2.1 years (range 1.2–4.1 y) after study enrollment. Their mean age was 36.2 ± 10.3 y and 59 % were female. Their hemoglobin types were: SS, 77.7 %; SC, 14.3 %; Sickle-thal.+, 6.3 %; and Sickle-thal.0, 1.8 %. At baseline, 40 patients had PHTN (mean TRV 2.75 m/sec) and their mean TRV at the 2 y follow up was 2.71 m/sec (p=0.45). In 6 subjects the TRV decreased to normal values from baselines of 2.5 – 3 m/sec. Nevertheless, the mortality of the patients diagnosed with PHTN at baseline currently stands at 40% at 40 months of follow-up. Seventy-three patients did not have PHTN at enrollment (mean TRV 2.0 m/sec) and as a group their TRV at the 2 y follow up had not changed significantly (mean 2.1, p=0.1). However, 11 of the 73 patients (15.1%) with initially normal TRV developed PHTN at 2 years (mean TRV 2.70, range 2.5–3.5 m/sec). The table shows that age, sex, Hb type, Hb F %, and hydroxyurea treatment of the patients who developed PHTN at the 2 y follow up were not significantly different from those who did not.

However, patients who developed PHTN were significantly more anemic, had higher reticulocyte counts, and higher serum ferritin values. A trend toward an increased bilirubin and LDH was observed. Hence, hemolysis probably played a pathogenetic role in these patients’ increased pulmonary pressures, as is also postulated for sickle patients who had PHTN at baseline.

These preliminary results suggest that the incidence of PHTN in adult sickle patients could be as high as 7 % per year and that ECHO screening of these patients every two years is probably indicated.