| Summary: | Background: Accuracy of brachial cuff blood pressure (BP) may be influenced by individual variability in central-to-peripheral systolic BP (SBP)-amplification, but this has never been determined. We aimed to achieve this by characterising SBP-amplification phenotypes and examining associations with cuff BP accuracy.
Methods: Intra-arterial BP was measured at the ascending aorta, brachial and radial arteries in 77 patients (aged 61.5±10.3 years 68% male) following coronary angiography. Cuff BP was measured bilaterally by oscillometric devices before catheterisation, and then simultaneously with intra-arterial brachial BP. SBP-amplification was defined by ≥5 mmHg SBP increase between the aorta-to-brachial or brachial-to-radial arteries.
Results: Average aortic-to-brachial and brachial-to-radial SBP-amplification were 8.5±9.5 mmHg and 6.4±9.4 mmHg respectively. However, four distinct SBP-amplification phenotypes were observed: 1) both aortic-to-brachial and brachial-to-radial SBP-amplification (n=24) 2) only aortic-to-brachial SBP-amplification (n=24) 3) only brachial-to-radial SBP-amplification (n=16) 4) no aortic-to-brachial or brachial-to-radial SBP-amplification (n=13). Compared with the first three phenotypes, patients with no SBP-amplification had elevated aortic SBP (143.1±23.0 mmHg versus 122.4±18.3 126.0±19.5 and 134.8±12 mmHg respectively p=0.0066) that was significantly underestimated by brachial cuff BP (−11.7±8.7 mmHg, p=0.004), despite no differences in clinical characteristics or cuff BP between phenotypes (p>0.1 all).
Conclusions: These are the first data to describe distinctive central-to-peripheral SBP-amplification phenotypes, and includes discovery of a phenotype in which cardiovascular risk is likely to be elevated because of significantly increased aortic SBP that is not detected by conventional cuff BP methods.
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