A RETROSPECTIVE STUDY OF RED CELL DISTRIBUTION WIDTH AND RIGHT VENTRICULAR SYSTOLIC PRESSURE IN PULMONARY HYPERTENSION

Abstract

SESSION TITLE: Pulmonary Vascular Disease Posters SESSION TYPE: Original Investigation Posters PRESENTED ON: October 18-21, 2020 PURPOSE: Red Cell Distribution Width (RDW), a measure that reflects the non-homogeneity in sizes of red cells, is a cheap and readily available parameter that has been correlated to various cardiac hemodynamic variables. The 6th World Symposium on Pulmonary Hypertension (PH) recently redefined PH to include all patients with a mean pulmonary artery pressure (mPAP) of greater than 20 mm Hg. Right Ventricular Systolic Pressure (RVSP) on transthoracic echocardiography is usually the first measured parameter when evaluating a patient for PH. We aimed to study the correlation between RDW and RVSP, so as to assess the potential role of RDW as a risk-stratifying aid for PH. METHODS: Patients who underwent right heart catheterization (RHC) at our center between November 2014 and November 2019 were included in this retrospective study. Exclusion criteria included patients under the age of 18, active malignancy, known hemoglobinopathy, blood transfusion within one month of laboratory testing, and lack of RDW measurement within 3 months of the RHC. Hemodynamic parameters obtained on RHC, as were hemoglobin and RDW values from the closest CBC obtained within 3 months of the RHC. Student’s t-test was used to compare RDW between patients with elevated RDW (> 14.5%) and normal RDW (≤ 14.5%). RDW was also compared between various cutoffs of RVSP. RESULTS: 342 patients were included in this study. A significantly higher RVSP was noted in the group with elevated RDW (> 14.5%, n = 130), as opposed to the group with normal RDW (≤ 14.5%, n = 212) (50.57 vs 41.39 mm Hg, p < 0.0001). Mean RDW was compared between high RVSP and non-elevated RSVP groups. When an RVSP > 35 mm Hg was used as the cutoff, there was a significant difference in RDW between the elevated (n = 233) and the normal (n = 109) groups (14.79 vs 13.82%, p < 0.0001). This held true when the cutoff was changed to an RSVP > 20 mm Hg; the elevated RSVP group (n = 336) tended to have a higher RVSP than the normal RVSP group (n = 6) (14.51 vs 12.9%, p = 0.0001). CONCLUSIONS: This study indicates a correlation between RDW and RVSP. This correlation may be a consequence of the association between RDW and mean pulmonary artery pressure (mPAP) in the setting of PH, which has been demonstrated in other previous studies. While the mechanism for this association is unknown, it is hypothesized to be a consequence of the nature of RDW to correlate to the level of inflammatory cytokines; PH is a disease with a significant inflammatory component. Alternatively, RDW may be tied to the level of subclinical hypoxia or hemolysis associated with microvascular disruption in PH. CLINICAL IMPLICATIONS: The measurement of RVSP is usually the first step in the evaluation of a patient with suspected PH. RDW, being a conveniently measured parameter on complete blood counts, appears to correlate with RVSP, and may have a role in pre-test risk stratification for PH. DISCLOSURES: No relevant relationships by Syed Haider, source=Admin input No relevant relationships by Pius Ochieng, source=Web Response No relevant relationships by Divya Ravi, source=Web Response No relevant relationships by NISHANT SHARMA, source=Web Response No relevant relationships by Metlapalli Venkata Sravanthi, source=Web Response No relevant relationships by Pandi Todhe, source=Web Response