Red Blood Cell Distribution Width and the Right Ventricle in Acute Pulmonary Embolism

SESSION TITLE: Venous Thromboembolism SESSION TYPE: Original Investigation Poster PRESENTED ON: Wednesday, November 1, 2017 at 01:30 PM - 02:30 PM PURPOSE: Red blood cell distribution width (RDW) is thought to be a marker of inflammation and has been associated with adverse outcomes in myocardial infarction, intensive care unit patients, heart failure, and recently in pulmonary embolism (PE). The main mechanism of death in patients who do not survive pulmonary embolism is right ventricular (RV) failure. The aim of our study was to examine the role of RDW in predicting RV dilation and hypokinesis on transthoracic echocardiogram. In particular, does RDW increase the positive predictive value (PPV) of RV dysfunction above the standard biomarkers used in PE. METHODS: In our urban teaching hospital, we created a prospective registry of all patients diagnosed with PE. We collected data on RDW values at time of PE diagnosis from May 2015 - March 2017 along with other clinical characteristics including RV dysfunction (dilation or hypokinesis) as reported by a cardiologist after reviewing transthoracic echocardiographic images as part of standard assessment of patients suffering from PE. We then retrospectively reviewed this data to determine if an elevated RDW value, defined as greater than 15.2 based on prior studies, had prognostic value for RV dilation and hypokinesis. Using cutoff values of 0.06ng/mL for Troponin I (TnI) and 100pg/mL for Brain Natriuretic Peptide (BNP), we were able to assess the added benefit of RDW in predicting these RV abnormalities. RESULTS: We found 208 patients diagnosed with PE who had all the above data available for analysis. Using global chi-squared test, we determined the area under the curve (AUC) for the detection of RV dilation of RDW, TnI+BNP, and RDW+TnI+BNP were 0.556 (p=0.143), 0.759 (p<0.001), and 0.768 (p<0.001), respectively. The AUC for detection of RV hypokinesis of RDW, TnI+BNP, and RDW+TnI+BNP were 0.539 (p=0.321), 0.775 (p<0.001), and 0.775 (p<0.001), respectively. RDW alone had a PPV (specificity) of 34% (56%) for RV dilation and 31% (55%) for RV hypokinesis. Combined TnI and BNP had a PPV of 63% (89%) for RV dilation and 60% (88%) for hypokinesis. When adding RDW, these values increased to 65% (94%) and 61% (94%), respectively. CONCLUSIONS: RDW values greater than 15.2 had poor predictive value for RV dilation or hypokinesis on echocardiogram. When added to an elevated troponin or BNP, an elevated RDW did not significantly increase the PPV for these findings. CLINICAL IMPLICATIONS: Higher RDW values do not predict RV dysfunction on transthoracic echocardiogram in patients with acute PE. Their role in the prediction of poor outcomes requires further investigation. DISCLOSURE: The following authors have nothing to disclose: Eric Bondarsky, Devi Sampat, Jason Filopei, Madeline Ehrlich, David Steiger No Product/Research Disclosure Information