5612390 CORRELATION OF DOPPLER DEFINED ELEVATED PULMONARY PRESSURE WITH LABORATORY PARAMETERS IN ADULT PATIENTS WITH SICKLE CELL DISEASE - A RETROSPECTIVE STUDY

Abstract

Background: Pulmonary hypertension (PH) is a relatively common complication and known cause of death in adult patients with sickle cell disease (SCD). Trans-thoracic Echocardiography is a non-invasive way to screen SCD patients for elevated pulmonary pressure. An estimation of the pulmonary artery systolic pressure can be made via assessment of the Tricuspid jet regurgitation velocity(TRV). TRV greater than or equal to 2.5 m/sec corresponds to an estimated Pulmonary Artery Systolic pressure of >35 mm Hg, which is approximately two standard deviations above normal 1.The prevalance of elevated pulmonary pressure in adults with SCD is 30-40%, while the prevalance of PH in SCD patients utilizing right heart catheterization (RHC) is between 6-10.5% 2. A major risk factor for PH in sickle cell disease is the severity of hemolytic anemia 3. The level of N terminal fragment of brain natriuretic peptide (NT ProBNP) correlates with the degree of pulmonary vascular resistance in SCD patients and may be an indirect reflection of the end organ damage 4. Aims: To analyse the prevalence of Doppler defined pulmonary hypertension in adult patients with Sickle cell Disease visiting our centre. To correlate the severity of hemolysis using laboratory parameters and NT-ProBNP with the severity of PH in these patients Methods: 92 patients with SCD underwent baseline clinical evaluation, laboratory testing, 2D echocardiography and NT-ProBNP analysis in our Hospital from November 2020 - December 2021. TRVmax of ≥2.5m/s, was used as a surrogate marker of Pulmonary Hypertension. The severity of PH was correlated with the degree of hemolysis and NT Pro BNP levels. Results: IBM SPSS Statistics 24.0 was used for Statistical Analysis. Doppler-defined pulmonary hypertension was found among 29 out of 92 patients denoting a prevalence of 31.5%. The prevalence among males was 20.9% and that among females was 40.8%. TRV max had significant positive correlation with NT-ProBNP(r=0.310,p<0.01) and with markers of hemolysis like LDH (r=0.322,p<0.01)and Reticulocyte count(r=0.212,p<0.05). Serum Ferritin(r=0.233,p<0.05),Hemoglobin S(%)(r=0.374,p<0.01) and Left Ventricular ejection fraction (LVEF) (r=0.352,p<0.01) also had significant correlation with TRV Max. Patients with high serum ferritin and HbS percent had higher TRV max while LVEF was low in those with high TRVmax. TRV Max also exhibited significant negative correlation with Hemoglobin (r=- 0.340, p<0.01). Summary: In our study, the prevalence of doppler - defined Pulmonary hypertension in adults with sickle cell disease was 31.5%. These patients had a positive correlation with markers of hemolysis and levels of NT-Pro BNP. Hence, we conclude, transthoracic echocardiography and NT proBNP can be used as a screening tool and surrogate test to Right heart catheterisation in order to diagnose PH in SCD patients in resource constrained settings.Both these tests have a high sensitivity in screening SCD patients with PH and having the advantage of being non-invasive procedure.