title: 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.
abstract: 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.
authors.affiliation: Department of Hematology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Eduard J
authors.initials: EJ
authors.lastname: van Beers
authors.forename: Berthe L F
authors.initials: BL
authors.lastname: van Eck-Smit
authors.forename: Melvin R
authors.initials: MR
authors.lastname: Mac Gillavry
authors.forename: Charlotte F J
authors.initials: CF
authors.lastname: van Tuijn
authors.forename: Joost W J
authors.initials: JW
authors.lastname: van Esser
authors.forename: Dees P M
authors.initials: DP
authors.lastname: Brandjes
authors.forename: Mies C
authors.initials: MC
authors.lastname: Kappers-Klunne
authors.forename: Ashley J
authors.initials: AJ
authors.lastname: Duits
authors.forename: Bart J
authors.initials: BJ
authors.lastname: Biemond
authors.forename: John-John B
authors.initials: JJ
authors.lastname: Schnog
mesh_terms: 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