Splenectomy: a strong risk factor for pulmonary hypertension in patients with thalassaemia

Abstract

Objective: To determine the association between splenectomy and pulmonary hypertension in patients with thalassaemia with anaemia. Design: Prospective cross-sectional study. Methods: 68 patients with thalassaemia, who had a haemoglobin concentration of less than 100 g/l, were recruited into this study. Echocardiography was performed before clinical data were reviewed. Pulmonary artery pressure was estimated by measuring the systolic transtricuspid pressure gradient from tricuspid regurgitation and adding it to the right atrial pressure, which was estimated by the response of the inferior vena cava to inspiration. Pulmonary hypertension was defined as systolic pulmonary artery pressure . 35 mm Hg. History of splenectomy and other clinical data were compared between patients with and without pulmonary hypertension. Results: 29 patients had pulmonary hypertension and 39 did not. Patients with pulmonary hypertension had significantly more nucleated red blood cells and higher platelet counts, and a higher prevalence of splenectomy (75.8% v 25.6%, odds ratio 9.1, 95% confidence interval 3.0 to 27.7). In multivariate analysis, splenectomy was the only factor significantly related to pulmonary hypertension. Conclusion: Splenectomy is a strong risk factor for pulmonary hypertension in patients with thalassaemia.H eart disease is a major cause of mortality and morbidity in patients with thalassaemia after the first decade of life, 1 despite improved prognosis with iron chelation. The common cardiac abnormalities that have been reported in patients with thalassaemia are cardiac hypertrophy, ventricular systolic dysfunction, pericarditis and pulmonary hypertension. Pulmonary hypertension is found in about 59-75% of patients with thalassaemia and can be the leading cause of heart failure in these patients.2 4 5 Factors affecting pulmonary artery pressure include high cardiac output caused by anaemia, left ventricular (LV) systolic dysfunction, chronic pulmonary haemosiderosis, recurrent respiratory tract infections, hypoxaemia and pulmonary fibrosis.5 6 Another proposed cause is the hypercoagulable state with thrombotic obstruction of the pulmonary arteries.7-9 Although most of the reported patients with thalassaemia with pulmonary hypertension were splenectomised, 2 5 6 non-splenectomised patients can also have pulmonary hypertension whereas some of them have normal pulmonary arterial pressure.2 The relationship between splenectomy and pulmonary hypertension in thalassaemia has not been clearly established. The purpose of this study was to explore this relationship. METHODS PatientsWe studied patients with thalassaemia with haemoglobin concentration less than 100 g/l who were being treated at the haematology outpatient clinic from January 2000 to December 2001. They were free from cardiac symptoms and had no evidence of clinical heart failure or signs of chronic liver disease. None were taking cardioactive drugs at the time of examination. We excluded patients with significant valvular heart disease, congenital heart diseas...

Risk factors and mortality associated with an elevated tricuspid regurgitant jet velocity measured by Doppler-echocardiography in thalassemia: a Thalassemia Clinical Research Network report

“…46 The association of PH with splenectomy and a hypercoagulable state also has been well described in the literature. 17,22,24,26 On the basis of our data, risk of a high TRV with age does not increase in nonsplenectomized patients, an observation not previously described. Circulating RBC-derived microvesicles found to be elevated in splenectomized thalassemia patients may play a role.…”

“…7,12 The etiology of PH in thalassemia is multifactorial, involving a complex interaction of platelets, the coagulation system, erythrocytes, and endothelial cells along with inflammatory and vascular mediators. 13,19 Contributing mechanisms include oxidative stress, 20 hemolysis, 21,22 thrombosis, [23][24][25] splenectomy, 17,22,26 abnormal arginine-nitric oxide bioavailability, 13,21 red cell membrane pathology, 27 and iron overload. 28 Although overlap in pathways contributing to vasculopathy and PH is expected in all forms of thalassemia, 13 the pathophysiology of PH is fundamentally different in patients with TI compared with TM.…”

Prevalence and Risk Factors for Pulmonary Arterial Hypertension in a Large Group of β-Thalassemia Patients Using Right Heart Catheterization

“…Previous studies relying solely on echocardiographic parameters reported prevalence rates ranging between 10% and 78.8% (averaging ≈30%). [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] The diagnosis was usually established based on a TRV exceeding 2.5-2. study, the prevalence of PAH was considerably lower when more strict echocardiographic criteria and confirmatory right heart catheterization were used. Owing to the systematic approach undertaken in our study, we believe that estimates presented in this report are more likely representative of the true PAH prevalence in patients with β-thalassemia.…”

Evaluation of Tricuspid Regurgitant Jet Velocity in Thalassemia Patients with Splenectomy

“…Poor treatment of thalassemia leads to low hemoglobin concentrations and more splenectomy. Patients with regular blood transfusion and appropriate iron chelation have a low incidence of splenomegaly and are less likely to develop PAH (20).…”