Pulsatile Load Components, Resistive Load and Incident Heart Failure: The Multi-Ethnic Study of Atherosclerosis (MESA).
BACKGROUND
Left ventricular (LV) afterload is composed of systemic vascular resistance (SVR) and components of pulsatile load, including total arterial compliance (TAC), and reflection magnitude (RM). RM, which affects the LV systolic loading sequence, has been shown to strongly predict HF. Effective arterial elastance (Ea) is a commonly used parameter initially proposed to be a lumped index of resistive and pulsatile afterload. We sought to assess how various LV afterload parameters predict heart failure (HF) risk and whether RM predicts HF independently from subclinical atherosclerosis.


METHODS
We studied 4345 MESA participants who underwent radial arterial tonometry and cardiac output (CO) measurements with the use of cardiac MRI. RM was computed as the ratio of the backward (Pb) to forward (Pf) waves. TAC was approximated as the ratio of stroke volume (SV) to central pulse pressure. SVR was computed as mean pressure/CO. Eawas computed as central end-systolic pressure/SV.


RESULTS
During 10.3 years of follow-up, 91 definite HF events occurred. SVR (P = .74), TAC (P = .81), and Ea(P = .81) were not predictive of HF risk. RM was associated with increased HF risk, even after adjustment for other parameters of arterial load, various confounders, and markers of subclinical atherosclerosis (standardized hazard ratio [HR] 1.49, 95% confidence interval [CI] 1.18-1.88; P = .001). Pbwas also associated with an increased risk of HF after adjustment for Pf(standardized HR 1.43, 95% CI 1.17-1.75; P = .001).


CONCLUSIONS
RM is an important independent predictor of HF risk, whereas TAC, SVR, and Eaare not. Our findings support the importance of the systolic LV loading sequence on HF risk, independently from subclinical atherosclerosis.
Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Perelman School of Medicine. Philadelphia, Pennsylvania. Electronic address: pzamani@upenn.edu.
Payman
P
Zamani
Division of Cardiovascular Medicine, Ohio State University Heart and Vascular Center, Columbus, Ohio.
Scott M
SM
Lilly
Biofluid, Tissue, and Solid Mechanics for Medical Applications, Ibitech, iMinds Medical IT, Ghent University, Ghent, Belgium.
Patrick
P
Segers
Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minnesota.
David R
DR
Jacobs
National Institutes of Health, Bethesda, Maryland; Departments of Radiology and Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland.
David A
DA
Bluemke
Division of Cardiology, School of Medicine, University of Minnesota. Minneapolis, Minnesota.
Daniel A
DA
Duprez
Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Perelman School of Medicine. Philadelphia, Pennsylvania.
Julio A
JA
Chirinos
D000368:Aged; D000369:Aged, 80 and over; D050197:Atherosclerosis / Q000150:complications / Q000208:ethnology* / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology; D005006:Ethnicity; D005260:Female; D006333:Heart Failure / Q000453:epidemiology* / Q000503:physiopathology*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D013318:Stroke Volume / Q000502:physiology; D014655:Vascular Resistance / Q000502:physiology; D044465:White People
Wave reflections; compliance; heart failure; vascular resistance