Measures of endothelial dysfunction predict response to cardiac resynchronisation therapy
David R Warriner1, Patricia Lawford2, Paul J Sheridan1
1Medical Physics Group, Department of Cardiovascular Science, University of Sheffield, Sheffield, UK; Department of Cardiology, Northern General Hospital, Sheffield Teaching Hospitals NHS Trust, Sheffield, UK.
Objectives:
Cardiac resynchronisation therapy (CRT) improves morbidity and mortality in heart failure (HF). Impaired endothelial function, as measured by flow-mediated dilation (FMD) is associated with increased morbidity and mortality in HF and may help to differentiate responders from non-responders.
Methods:
19 patients were recruited, comprising 94% men, mean age 69±8 years, New York Heart Association functional classes II-IV, QRSd 161±21 ms and mean left ventricular ejection fraction 26±8%. Markers of response and FMD were measured at baseline, 6 and 12 months following CRT.
Results:
14 patients were responders to CRT. Responders had significant improvements in VO2 (12.6±1.7 to 14.7±1.5 mL/kg/min, p<0.05), quality of life score (44.4±22.9-24.1±21.3, p<0.01), left ventricular end diastolic volume (201.5±72.5 mL-121.3±72.0 mL, p<0.01) and 6-min walk distance (374.0±112.8 m at baseline to 418.1±105.3 m, p<0.05). Baseline FMD in responders was 2.9±1.9% and 7.4±3.73% in non-responders (p<0.05).
Conclusions:
Response to CRT at 6 and 12 months is predicted by baseline FMD. This study confirms that FMD identifies responders to CRT, due to endothelium-dependent mechanisms alone.
