Digital Photoplethysmography for Assessment of Arterial Stiffness: Repeatability and Comparison with Applanation Tonometry.
BACKGROUND
Arterial stiffness is an independent risk factor for cardiovascular morbidity and can be assessed by applanation tonometry by measuring pulse wave velocity (PWV) and augmentation index (AIX) by pressure pulse wave analysis (PWA). As an inexpensive and operator independent alternative, photoelectric plethysmography (PPG) has been introduced with analysis of the digital volume pulse wave (DPA) and its second derivatives of wave reflections.


OBJECTIVE
The objective was to investigate the repeatability of arterial stiffness parameters measured by digital pulse wave analysis (DPA) and the associations to applanation tonometry parameters.


RESULTS
112 pregnant and non-pregnant individuals of different ages and genders were examined with SphygmoCor arterial wall tonometry and Meridian DPA finger photoplethysmography. Coefficients of repeatability, Bland-Altman plots, intraclass correlation coefficients and correlations to heart rate (HR) and body height were calculated for DPA variables, and the DPA variables were compared to tonometry variables left ventricular ejection time (LVET), PWV and AIX. No DPA variable showed any systematic measurement error or excellent repeatability, but dicrotic index (DI), dicrotic dilatation index (DDI), cardiac ejection elasticity index (EEI), aging index (AI) and second derivatives of the crude pulse wave curve, b/a and e/a, showed good repeatability. Overall, the correlations to AIX were better than to PWV, with correlations coefficients >0.70 for EEI, AI and b/a. Considering the level of repeatability and the correlations to tonometry, the overall best DPA parameters were EEI, AI and b/a. The two pansystolic time parameters, ejection time compensated (ETc) by DPA and LVET by tonometry, showed a significant but weak correlation.


CONCLUSIONS
For estimation of the LV function, ETc, EEI and b/a are suitable, for large artery stiffness EEI, and for small arteries DI and DDI. The only global parameter, AI, showed a high repeatability and the overall best correlations with AIX and PWV.
Department of Obstetrics and Gynecology, Institution of Clinical Sciences, Skåne University Hospital, Lund University, Malmö, Sweden.
Emma
E
von Wowern
Medical Research Unit, Department of Internal Medicine, Institution of Clinical Sciences, Skåne University Hospital, Lund University, Malmö, Sweden.
Gerd
G
Östling
Medical Research Unit, Department of Internal Medicine, Institution of Clinical Sciences, Skåne University Hospital, Lund University, Malmö, Sweden.
Peter M
PM
Nilsson
Department of Obstetrics and Gynecology, Institution of Clinical Sciences, Skåne University Hospital, Lund University, Malmö, Sweden.
Per
P
Olofsson
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001011:Aorta / Q000502:physiology; D001158:Arteries / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D004548:Elasticity / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008365:Manometry / Q000379:methods; D008875:Middle Aged; D017156:Photoplethysmography / Q000379:methods; D011247:Pregnancy; D011674:Pulse / Q000379:methods; D063177:Pulse Wave Analysis / Q000379:methods; D012307:Risk Factors; D059289:Vascular Stiffness / Q000502:physiology*; D055815:Young Adult