Table 2.

Summary of the studies regarding wave reflection parameters.

References	Population	Aim	Wave reflection parameters	Findings	Conclusions
Heffernan et al.23	55 healthy men (25 African American, 30 Whites)	Ethnic differences in arterial function related to central pressure	AIx and transiet time (Tr) with applanation tonometry	African-American men had greater aortic stiffness and AIx, reduced aortic Tr compared with White men (P < 0.05) with similar level of brachial BP (but greater central BP).	African-American men have greater central BP and wave reflection, despite comparable brachial BP, compared with young White men.
Lemogoum et al.24	Black (n = 30) and White (n = 30) smokers	Ethnic differences in smoking effects on PWV and augmentation index (AIx).	AIx with Complior device	Smoking increase AIx and PWV. Blacks disclose larger increases in AIx adjusted for heart rate and PWV normalized for BP.	Smoking acutely increases PWV and AIx in Blacks more than in Whites.
Shen et al.25	Community-middle age cohort n = 951 African Americans (AAs) and White	To evaluate the relationship between metabolic syndrome (MetS) and vascular function	AIx with Sphygmocor	MetS is associated with increased PWV and AIx in both races. In subjects without MetS, AAs had higher PWV and AIx compared with White subjects. Adding BP effect racial differences disappear	MetS is associated with increased arterial stiffness in both racial groups, AAs without MetS have greater vascular dysfunction but additional weighting for hypertension attenuated the racial differences
Sugawara et al.26	47 White adults (45 years) and 94 age-matched Asian adults	Ethnic differences in central (cAIx) and peripheral AIx (pAIx).	Radial AIx: tonometry-based automated radial AI measurement device. Carotid arterial waveforms	cAIx and pAIx tend to be lower in White compared with Asian adults (P < 0.10 for both). Such tendency disappears when height is taken into account.	pAIx may provide a surrogate measure of cAI irrespective of difference in race
Chirinos et al.27	10,550 adults multi-ethnic cohort	Ethnic differences in wave reflections. Reference values.	AIx with Sphygmocor	Black African and Andean Hispanics have higher central AIx compared to White British whereas American Indians had lower, no significant differences between Chinese and British Whites.	Marked ethnic differences in augmentation index exist, which may contribute to ethnic differences in hypertensive organ damage.
Sibiya et al.28	808 cohort of Black African ancestry (283 men)	Influence of gender in the relationship between wave reflection parameters and target organ damage	AIx with SphygmoCor	In men, but not in women, AIx derived from aortic augmentation pressure/central aortic pulse pressure and AIx derived from the second peak/first peak of the aortic pulse wave are associated with left ventricular mass index (LVMI).	Radial applanation tonometry-derived AIx may account for less of the variation in end-organ changes in women as compared with men.
Zhang et al.20	Multi-ethnic type 2 diabetes Asian cohort: Chinese (n = 1045), Malays (n = 458) and Indians (n = 468).	Ethnic disparity in arterial stiffness	AIx applanation tonometry	AIx higher in Indians (28.1 ± 10.8%) than Malays (25.9 ± 10.1%) and Chinese (26.1 ± 10.7%) (P < 0.001). In fully adjusted models (age, gender, BMI, SBP, DBP and height). Indians remain associated with higher AI (β = 2.776, P < 0.001).	Malays and Indians with diabetes have higher AIx which may explain their higher risk for adverse outcomes.