Abstract WMP51: Baseline Ct Perfusion Parameters Differ In Large Vessel Occlusion Stroke Patients With Reduced Left Ventricular Ejection Fraction

Introduction: Reduced left ventricular ejection fraction (EF) is associated with worse outcomes after stroke. CT perfusion (CTP) is widely used in acute stroke evaluation; its reliability in patients with reduced EF is unknown. We hypothesized that patients with reduced EF would have abnormal dose-time curves that may impair standard perfusion maps and reduce their quality. Methods: A retrospective database of all patients presenting to Stanford University for large vessel occlusion (LVO) stroke between 2010-2019 was used. CTPs were post-processed using RAPID software. Concentration-time curve metrics—width of the venous output function (VOF) at half maximum amplitude and VOF peak amplitude—were assessed automatically for each case. A reader blinded to EF visually evaluated the VOF curve for evidence of truncation (yes/no) and graded the quality of the time to maximum (Tmax) map on a scale from 0 (excellent) to 3 (poor), based on the degree of “speckling” present on the map. Continuous parameters were compared using the t-test or Mann-Whitney test and dichotomous parameters with the Fisher’s exact or Chi-square test, where appropriate. Results: 160 patients with sufficient quality baseline CTP and in-hospital echocardiogram were evaluated; 34 had EF <50%. Mean age, scan time, and cumulative contrast dose did not differ; men were more prevalent in the reduced EF group (68% vs 44%; p=0.016). Compared to patients with normal EF, patients with low EF more often had truncation of the VOF (11.8% vs 0.8%; p=0.007), had a lower VOF peak amplitude (mean 245.04 HU vs 299.07; p=0.013, 95% CI for difference 11.61 to 96.45), had wider VOF at half maximum amplitude (mean 17.84 seconds vs 14.56; p<0.0001, 1.9 to 4.65), and had worse Tmax quality (median 2 (IQR 1-3) vs 1 (0-2); p=0.002). Conclusion: Patients with reduced EF have dispersion of the contrast bolus as evidenced by a VOF curve that is wider and has a lower peak. Consequently, the quality of the Tmax map in patients with low EF is reduced, which may render automated CTP results unreliable. Additional studies are needed to determine to what extent poor CTP image quality in patients with low EF affects treatment decisions.