Abstract 2156

Introduction:

Clinically significant pulmonary arterial hypertension (PAH) has been reported in splenectomized hemoglobin E/β-Thalassemia patients. Like primary PAH, the underlying basis is hypercoagulability related thrombotic pulmonary arteriopathy, which results in an increased pulmonary vascular resistance. In the non-splenectomized counterparts with no clear evidence of hypercoagulability only mild PAH is found. To evaluate role of splenomegaly and the accompanying increased blood volume in the pathogenesis of PAH in this group of patients, we studied the relationship between spleen volume and PA pressure.

Patients and Methods:

Nineteen clinically stable hemoglobin E/β-Thalassemia outpatients, on no medication aside from folic acid and who received no blood transfusion in the preceding 4 weeks were first analyzed in this ongoing study. All gave written informed consent, and study protocol was approved by the institution ethics committee on studies in humans (ID 07–53-01). PA pressure (PAP) was estimated by a single echocardiologist (T.Y.) using Philips iE33 echocardiographic system with a S5 probe (Philips Medical Systems, Andover, MA). Spleen volume was determined by CT scan with non-contrast, 320-slice, 3 mm axial cut (Aquilion one, Toshiba, Japan). Statistical analysis of clinical and laboratory data was done by SPSS version 18 (SPSS Inc, Chicago, Ill), considering a P value <0.05 as statistically significant. Results: Patients' characteristics are shown. Results are expressed as mean ± SD or median (range) where appropriate. All had normal left ventricular systolic ejection fraction and no valvular heart disease. There was good correlation (r=0.609, P=0.006) between spleen volume and mean PAP.

Number of patients19
Gender, M: F 15: 4 
Age (yrs) 37.4 ± 12.6 
Total blood transfusion (unit) 9 (0–165) 
Fe chelation Rx 10 
Hb (g/dL) 7.56 ± 1.11 
Ferritin (ng/mL) 670 (231–2,100) 
Anti-HIV, Anti HCV, HBsAb 0, 1, 1 
hs CRP (mg/L) 0.96 (0–3.85) 
Liver hemochromatosis by CT scan 16 
Extramedullary hematopoiesis thoracic area, spleen 87, 1 
Spleen volume (mL), 1,400 ± 379 
Mean PA pressure (mmHg) 17.3 ± 4.5 
Number of patients19
Gender, M: F 15: 4 
Age (yrs) 37.4 ± 12.6 
Total blood transfusion (unit) 9 (0–165) 
Fe chelation Rx 10 
Hb (g/dL) 7.56 ± 1.11 
Ferritin (ng/mL) 670 (231–2,100) 
Anti-HIV, Anti HCV, HBsAb 0, 1, 1 
hs CRP (mg/L) 0.96 (0–3.85) 
Liver hemochromatosis by CT scan 16 
Extramedullary hematopoiesis thoracic area, spleen 87, 1 
Spleen volume (mL), 1,400 ± 379 
Mean PA pressure (mmHg) 17.3 ± 4.5 
Conclusions:

Non-splenectomized patients with hemoglobin E/β-Thalassemia have elevated PAP in proportion to spleen size, likely secondary to elevated blood volume. This situation is distinct from the pathologic PAH that results from increased pulmonary vascular resistance in splenectomized patients.

Disclosures:

No relevant conflicts of interest to declare.

Author notes

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Asterisk with author names denotes non-ASH members.