Radial augmentation index unmasks premature coronary artery disease in younger males

The augmentation index, a marker of arterial wave reflection, is considered to indicate cardiovascular risk burden, particularly in younger persons. We assessed whether the easily obtainable radial augmentation index (rAIx) is superior to systolic blood pressure (SBP) or pulse pressure (PP) in detecting atherosclerotic vascular disease at an early age.

We determined rAIx by applanation tonometry, SBP and PP in 152 male patients with or without invasively documented coronary artery disease (CAD). Ejection fraction (EF) was visually estimated by echocardiography or left ventricular angiography.

In younger patients (age < or =60 years, EF > or =30%), rAIx was significantly higher in patients with CAD (79.8+/-13.5%, n=31) compared with patients without CAD (68.5+/-22.0%, n=21; P = 0.04), whereas SBP (121+/-16 vs. 131+/-18 mmHg, P=0.04) and PP (48.7+/-9.4 vs. 56.3+/-12.1 mmHg, P=0.01) were even lower in patients with CAD compared with patients without CAD. In patients aged < or =60 years, rAIx was highest when EF was less than 30% (90.0+/-9.2%) compared with patients with EF 30-54% (80.7+/-11.5%) or EF > or =55% (72.1+/-20.4%, P=0.01). In contrast, in patients above 60 years of age, rAIx, SBP or PP did not differ between patients with or without CAD and the rAIx tended to be lowest in patients with severely reduced EF (P=0.07).

We conclude that premature vascular disease in younger patients with CAD is reflected only by an elevated rAIx, and not by SBP or PP. The rAIx is not suited to distinguish between older patients with high or low cardiovascular risk. Age seems to influence the interplay between rAIx and systolic heart function.