P709Improvement in endothelial function and arterial elastic properties facilitates response to cardiac resynchronization therapy

Abstract Background Cardiac resynchronization therapy (CRT) is a well-established therapy in heart failure (HF) patients with prolonged QRS. In HF patients, reduced nitric oxide availability and increased oxidative stress promote endothelial dysfunction (ED) and arterial stiffness. Purpose To investigate the pathophysiologic changes in endothelium and arterial elastic properties in CRT patients and their correlation to therapy. Methods We studied 32 HF patients before and 3 months after CRT implantation. In each visit we performed a 12-lead ECG and assessed markers of endothelial function. Specifically, we examined flow-mediated dilatation of the brachial artery (FMD), carotid to femoral pulse wave velocity (cfPWV), as well as the layer of endothelial glycocalyx using the Perfused Boundary Region (PBR) of the sublingual microvessel range: 5–25 microns. We also evaluated left ventricle ejection fraction (LVEF), left ventricle (LV) global longitudinal strain (GLS) and arterial elastance (Ea) to ventricular elastance (Ees) ratio (Ea/Ees) by echocardiography. Results 32 HF CRT patients, at age 65.5 (±10.9) years, with reduced LVEF (baseline LVEF: 27±7%, LVESV: 151±42 ml, GLS: 6.47±2.89%) were followed-up for a median of 115 days (IQR: 36). During follow up, all markers of ED demonstrated significant change: FMD was increased by 4.37±3.34% (p<0.001), cfPWV and PBR 5–25 were reduced by 1.10±1.56 (p=0.003) and 0.13±0.25 microns (p=0.028) respectively. LVEF was significantly increased (mean change: 7.50±4.77%) and LVESV was significantly reduced (mean change: −26.91±17.20 ml). 16 of 32 patients were responders (LVESV change ≥15% compared to baseline). Among the changes of the examined markers during follow-up, response to CRT correlated with the change of FMD (OR: 3.10, 95% CI: 1.47–15.51, p=0.039) and change of Ea/Ees (OR: 0.000, 95% CI: 0.000–0.061, p=0,0239). Effect of change in measurements during follow-up on response to CRT Measurement OR (95% CI) Main effect p-value FMD change 3.100 (1.470–15.513) 0.0397 cfPWV change 0.669 (0.295–1.354) 0.0622 PBR 5–25 change 1.773 (0.008–455.458) 0.828 Ea/Ees change 0.000 (0.000–0.061) 0.0239 Conclusion Improvement in endothelial function and arterial elastic properties evaluated by FMD and Ea/Ees respectively are related with effective CRT.