Chest
Volume 133, Issue 3, March 2008, Pages 646-652
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ORIGINAL RESEARCH
PULMONARY VASCULAR DISEASE
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

https://doi.org/10.1378/chest.07-1694Get rights and content

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 ≥ 2.5 m/s) employing echocardiography and were evaluated for pulmonary artery obstruction with ventilation-perfusion (VQ) scintigraphy.

Results

Fifty-three HbSS, 6 HbSβ0-thalassemia, 20 HbSC, and 6 HbSβ+-thalassemia patients were included. The overall prevalence of PHT was 41% in HbSS/HbSβ0-thalassemia patients and 13% in HbSC/HbSβ+-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/HbSβ0-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/HbSβ0-thalassemia patients without PHT (p = 0.31). In HbSC/HbSβ+-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/HbSβ+-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.

Section snippets

Patients

Consecutive SCD patients visiting the outpatient hematology/internal medicine clinics of the Academic Medical Center (Amsterdam, the Netherlands), the Slotervaart Hospital (Amsterdam, the Netherlands), and the Erasmus Medical Center (Rotterdam, the Netherlands) were eligible for this study. Inclusion criteria were high-performance liquid chromatography-confirmed diagnosis of SCD, age ≥ 18 years, and written informed consent. Exclusion criteria were known congestive heart failure, known COPD,

Patients

Ninety consecutive patients were eligible for the study, 5 of whom declined participation. Eighty-five patients were included in the study. For data analysis, the more severe SCD genotypes, HbSS and HbSβ0-thalassemia, were grouped together, as were the relatively milder SCD genotypes HbSβ+-thalassemia and HbSC.1920 For patient demographics, see Table 1.

Transthoracic Echocardiography

Transthoracic echocardiography was performed in 78 of the 85 included patients because 7 patients failed to meet their appointment on several

Discussion

A landmark study1 demonstrated that PHT occurs in approximately 30% of adult SCD patients and carries a strongly increased risk of death as compared to SCD patients without PHT. Given this risk of early death, it is of paramount importance to identify treatable causes and/or aggravating factors of PHT in SCD. In this study, we investigated the potential role of pulmonary artery obstruction as a causative or contributing factor in SCD patients with PHT employing VQ scintigraphy. VQ scintigraphy

ACKNOWLEDGMENT

Dr. C. Hoefnagel, Dr. A. de Groot, Dr. C. Schotborgh, Dr. K.W. Lagrand, and Ms. A. Karisli are gratefully acknowledged for contributing to the study design and execution.

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  • Cited by (0)

    The authors have no conflicts of interest to disclose.

    The CURAMA study group is a collaborative effort studying SCD in the Netherlands Antilles and the Netherlands. Participating centers include The Red Cross Blood Bank Foundation, Curaçao, the Netherlands Antilles; The Antillean Institute for Health Research, Curaçao, the Netherlands Antilles; The Department of Internal Medicine, Slotervaart Hospital, Amsterdam, the Netherlands; the Department of Vascular Medicine and the Department of Hematology, Academic Medical Center, Amsterdam, the Netherlands; the Department of Hematology, Erasmus Medical Center, Rotterdam, the Netherlands; the Department of Pathology, Groningen University Hospital, Groningen, the Netherlands; the Department of Internal Medicine, the Laboratory of Clinical Thrombosis and Hemostasis, and the Cardiovascular Research Institute, Academic Hospital Maastricht, Maastricht, the Netherlands

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