Pericardial Effusion Is a Marker of Increased Mortality in Thalassemia Major Patients

Introduction. In different types of not-hematological diseases the presence of a small pericardial effusion (PE) was associated with worse survival even after adjustment for patient characteristics, suggesting that it is a marker of underlying disease.In thalassemia major (TM) pericardial effusion was shown to be one of the manifestations of heart disease but its potential prognostic importance has never been investigated in the modern era. Cardiovascular Magnetic Resonance (CMR) by cine SSFP sequences was demonstrated to be extremely sensitive to even a small amount of PE.

This is the first prospective study evaluating if the presence of pericardial effusion is associated with increased mortality in TM.

Methods. 1259 patients (648 females, mean age 31.02 ± 8.64 years) enrolled in the Myocardial Iron Overload in Thalassemia (MIOT) were prospectively followed from their first Magnetic Resonance Imaging (MRI) scan. CMR was used to quantify myocardial iron (MIO) overload by a multislice multiecho T2* approach and to assess biventricular function parameters and to detect PE by cine SSFP sequences.

Results. PE was present in 25 (2.0%) patients.Patients with and without PE were comparable for age and ratio of men/women. At the baseline, the percentage of patients with MIO (global heart T2* value < 20 ms) was comparable between patients with and without PE (12.0 % vs 28.7%; P=0.074) and left ventricular and right ventricular ejection fractions were not significantly different between the two groups.

Mean follow-up (FU) time was 44.55 ± 20.35 months and there were 15 deaths.

Mortality was greater for patients with PE compared to those without an effusion (8.0% vs 1.1%, P=0.034).

PE was a significant predictive factor for death (hazard ratio-HR=12.64, 95%CI=2.78-57.42, P=0.001). PE remained a significant prognosticator for death also in a multivariate model including MIO ms (PE: HR=17.36, 95%CI=3.65-82.62, P<0.0001and global heart T2* < 20 ms: HR=3.07, 95%CI=1.07-8.75, P=0.036).

Conclusions. PE is quite rare in TM patients and it is not related to myocardial iron overload. An important role in the development of PE could be played by the 'iron-induced' pericardial siderosis but, due to the limitations of the current non-invasive CMR techniques, we were not able to address this issue.

PE was found to be a strong predictor for death, independently by the presence of myocardial iron overload. The non-invasive diagnosis of pericardial effusion is important for a more complete definition of the cardiac involvement of TM patients. The increased risk of death associated with PE may be used along with other clinical characteristics when estimating a patient's prognosis and monitoring.