The Pros and Cons of Splenectomy in Transfusion Dependent Thalassemia Patient

Introduction

One of the treatment modalities in transfusion dependent thalassemia (TDT) patient is splenectomy which aims to ameliorate red cell transfusion. However, not all thalassemia patients respond to splenectomy. Moreover, splenectomy may increase many unfavorable consequences. The study about the efficacy and complications after splenectomy is limited and the effect of splenectomy on iron overload is still unclear.

This study aims to investigate the long-term efficacy of splenectomy, factor predicting a response to splenectomy, the consequences of splenectomy complications, CBC parameter changes and the effect on iron overload parameters after splenectomy.

Methods

All TDT patients (PRC transfusion ≥3 units/year), aged >15 years who had splenectomy were recruited from our hematology division data base. Clinical characteristics including age, sex, age at splenectomy, operation date, hemoglobin (Hb) typing were collected. PRC transfusion requirement (unit/year) and CBC were collected 1 year before splenectomy, 1 year and 5 year post splenectomy.

In the complication cohort, TDT patients with intact spleen were recruited into control group. The sample size was calculated that at least 33 patients (66.6% from splenectomy group and 33.3% from non-splenectomy group) needed to be recruited to have 80% power to detect a difference in complication at an alpha level of 0.05.

The diagnosis of pulmonary hypertension (PHT) was based on the echocardiogram performed by the cardiologist and using definition from the 2015 ESC guideline. The thrombosis events were collected from medical record. The iron overload was compared by serum ferritin, liver iron concentration (LIC) and cardiac iron concentration were assessed by MRI of liver and cardiac T2*.

The associated factors of efficacy and complication for splenectomy were compared using Chi-squared test or Fisher exact test for categorical variables and T-test or Mann-Whitney test and repeated measure mixed model for continuous variables. Multivariate regression analysis was used to identify relationships between variables with the level of significance was defined as P value <0.05.

Results

Fifty TDT patients were included from the data base. In term of splenectomy efficacy, 21 patients (42%) has been changed from TDT to non-transfusion dependent thalassemia (NTDT) patients after splenectomy and 25 patients (50%) had 50% reduction in PRC transfusion. The significant factors associated with changing from TDT to NTDT were genotype of thalassemia (P=0.001). HbH disease and beta thalassemia/HbE (β/E) patients were the group who had higher response (28.57% and 52.38%, respectively) compared to HbH with CS (9.52%) and homozygous beta-thalassemia (9.51%). Lower percentage of neutrophils (<50%) was associated with lower response (P=0.02). Older age at the time of splenectomy (>10 year old) was associated with higher response after splenectomy (P = 0.005).

CBC before splenectomy, 1 and 5 years after splenectomy were compared. Mean Hb level was increased from 6.0 to 8.2 and 7.7 g/dL (P<0.001) and platelet was increased from 234,866 to 714,473 and 675,579 cells/cu.mm. (P<0.001).

Sixty-four patients were included in the complication cohort, (44 patients in splenectomy group and 20 patients in non-splenectomy group). The baseline characteristics including age, sex, Hb, ferritin were similar between 2 groups. The splenectomy group had significant higher tricuspid valve regurgitation velocity (TRV) compared to non-splenectomy group (2.54 m/s vs. 2.31 m/s, P=0.029). The prevalence of PHT and thrombosis were higher in splenectomy group (27.3% vs. 15% and 9.1% vs. 0%, respectively). Serum ferritin, LIC and cardiac T2* were not different between the 2 groups. From multivariable analysis, the only significant factor for predicting PHT was the longer duration after splenectomy (p=0.045).

Conclusion

Splenectomy had benefit in some TDT patients. Factors that predict a higher response to splenectomy were thalassemia type (HbH and β/E), higher neutrophil percentage and older age at the time at splenectomy. Hb and platelet was significantly increased after splenectomy.

In term of complication, splenectomy group had significant higher TRV and tended to have more prevalence of PHT and thrombosis. The longer time post splenectomy was the only significant factor for developing PHT.

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