840 ASSESSMENT OF ABSOLUTE CORONARY FLOW AND MICROVASCULAR RESISTANCE RESERVE IN PATIENTS WITH AORTIC STENOSIS

Abstract Introduction The development of left ventricular hypertrophy in patients with severe aortic stenosis (AS) is accompanied by adaptive coronary flow regulation, both epicardial and microvascular compartment, which ultimately lead to a chronic ischemic insult even the absence obstructive artery disease. Intracoronary continuous thermodilution saline through dedicated infusion catheter (RayFlow ®) novel tool that allows measure absolute resistance at rest during hyperemia calculate reserve (CFR) Microvascular Resistance Reserve (MRR) Purpose We aimed assess flow, resistance, CFR MRR AS, assessed intracoronary thermodilution, comparing these hemodynamic findings propensity-score matched contemporary cohort without AS. Methods Absolute blood were measured 29 AS compared 15 controls for age, gender, diabetes mellitus functional severity lesions. Myocardial work, total myocardial mass LAD-specific quantified echocardiography cardiac-CT. Results Patients presented significantly positive LV remodeling lower global longitudinal strain higher work index (p<0.02). Total Compared controls, resting LAD was (86 [66–107] ml/min vs 68 [52–75] ml/min, p=0.036), resulting, (2.30 ± 0.69 2.89 0.77, p=0.005) (2.73 0.74 3.53 0.95, (Figure 1). No differences found hyperemic resistances. Interestingly, perfusion (calculated as ratio between subtended expressed mL/min/g), but not resting, group (1.9 [1.5–2.5] ml/min/g 2.3 [2–3.1] p=0.036). Conclusions In non-obstructive disease, progression LVH, compensatory mechanism increased maintains an adequate rest, 2). As consequence, are impaired.