Large and medium-sized pulmonary artery obstruction does not play a role of primary importance in the etiology of sickle-cell disease-associated pulmonary hypertension.
BACKGROUND
Pulmonary hypertension (PHT) occurs in approximately 30% of adult patients with sickle-cell disease (SCD) and is a risk factor for early death. The potential role of pulmonary artery obstruction, whether due to emboli or in situ thrombosis, in the etiology of SCD-related PHT is unknown.


METHODS
Consecutive SCD patients were screened for PHT (defined as a tricuspid regurgitant jet flow velocity > or = 2.5 m/s) employing echocardiography and were evaluated for pulmonary artery obstruction with ventilation-perfusion (VQ) scintigraphy.


RESULTS
Fifty-three HbSS, 6 HbSbeta(0)-thalassemia, 20 HbSC, and 6 HbSbeta(+)-thalassemia patients were included. The overall prevalence of PHT was 41% in HbSS/HbSbeta(0)-thalassemia patients and 13% in HbSC/HbSbeta(+)-thalassemia patients. High-probability VQ defects (Prospective Investigation of Pulmonary Embolism Diagnosis criteria) were detected in two patients, one of whom had PHT. In HbSS/HbSbeta(0)-thalassemia patients with PHT, 19 patients (86%), 2 patients (9%), and 1 patient (5%) had low-, intermediate-, or high-probability scan results as compared to 30 patients (97%), 1 patient (3%), and 0 patients (0%) in HbSS/HbSbeta(0)-thalassemia patients without PHT (p = 0.31). In HbSC/HbSbeta(+)-thalassemia patients with PHT, 3 patients (100%), 0 patients (0%), and 0 patients (0%) had low-, intermediate-, and a high-probability scan as compared to 19 patients (90%), 1 patient (5%), and 1 patient (5%) in HbSC/HbSbeta(+)-thalassemia patients without PHT (p = 0.86). There were no statistical differences in irregular distribution of the radiopharmaceutical or nonspecific signs associated with PHT between patients with and without PHT.


CONCLUSIONS
Although small pulmonary artery obstruction cannot be excluded, large to medium-sized pulmonary artery obstruction is an unlikely primary causative factor in SCD-related PHT.
van Beers
Eduard J
EJ
Department of Hematology, Academic Medical Center, Amsterdam, the Netherlands.
van Eck-Smit
Berthe L F
BL
Mac Gillavry
Melvin R
MR
van Tuijn
Charlotte F J
CF
van Esser
Joost W J
JW
Brandjes
Dees P M
DP
Kappers-Klunne
Mies C
MC
Duits
Ashley J
AJ
Biemond
Bart J
BJ
Schnog
John-John B
JJ
D000328:Adult; D000755:Anemia, Sickle Cell / Q000150:complications* / Q000175:diagnosis; D001157:Arterial Occlusive Diseases / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D004452:Echocardiography; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D015995:Prevalence; D011379:Prognosis; D011651:Pulmonary Artery; D011669:Pulmonary Wedge Pressure / Q000502:physiology*; D012720:Severity of Illness Index; D015996:Survival Rate