Crucial Effect of Calibration Methods on the Association Between Central Pulsatile Indices and Coronary Atherosclerosis

BACKGROUND: Several studies have reported that central systolic blood pressure (SBP) estimation is affected by calibration methods. However, whether central pulsatile indices, namely pulse pressure (PP) and fractional PP (FPP) (defined as PP/mean arterial pressure (MAP)), also depend on calibration methods remains uninvestigated. This study assessed the accuracy and discriminatory ability of these indices for coronary atherosclerosis using 2 calibration methods. METHODS: Post-hoc analysis of a previous cross-sectional study (n = 139) that investigated the association between central pulsatile indices and coronary atherosclerosis. A validated-oscillometric device provided PP and FPP at the brachial artery (bPP and bFPP) and central artery using 2 calibration methods: brachial SBP/diastolic BP (DBP) (cPPsd and cFPPsd) and MAP/DBP (cPPmd and cFPPmd). Accuracy was assessed against invasive measurements (cPPinv and cFPPinv). Multivariate logistic and linear regression analyses were performed to assess the association between pulsatile indices and the presence of coronary artery disease (CAD) and SYNTAX score, respectively. RESULTS: cPPmd and cFPPmd were closer to invasive values than cPPsd (cPPsd: 39.6±12.6; cPPmd: 60.2±20.1; cPPinv: 71.4±22.9). cFPP exhibited similar results (cFPPsd: 0.35±0.09; cFPPmd: 0.55±0.14; cFPPinv: 0.70±0.19). In patients ≥70 years, only cFPPmd was significantly associated with CAD risk (odds ratio: 1.66 (95% confidence interval: 1.05-2.64)). SYNTAX score was significantly correlated with cPPmd, cFPPmd, and bFPP (standardized β: cPPmd 0.39, cFPPmd 0.50, bFPP 0.42, all P < 0.01). No significant association was observed in patients aged <70 years. CONCLUSIONS: Central pulsatile indices calibrated with brachial MAP/DBP were more accurate and discriminatory for coronary atherosclerosis than SBP/DBP calibration.