Prediction of Cardiovascular Events by Type I Central Systolic Blood Pressure: A Prospective Study

Compared with brachial blood pressure (BP), central systolic BP (SBP) can provide a better indication of the hemodynamic strain inflicted on target organs, but it is unclear whether this translates into improved cardiovascular risk stratification. We aimed to assess which of central or brachial BP best predicts cardiovascular risk and to identify the central SBP threshold associated with increased risk of future cardiovascular events. This study included 13 461 participants of CARTaGENE with available central BP and follow-up data from administrative databases but without cardiovascular disease or antihypertensive medication. Central BP was estimated by radial artery tonometry, calibrated for brachial SBP and diastolic BP (type I), and a generalized transfer function (SphygmoCor). The outcome was major adverse cardiovascular events. Cox proportional-hazards models, differences in areas under the curves, net reclassification indices, and integrated discrimination indices were calculated. Youden index was used to identify SBP thresholds. Over a median follow-up of 8.75 years, 1327 major adverse cardiovascular events occurred. The differences in areas under the curves, net reclassification indices, and integrated discrimination indices were of 0.2% ([95% CI, 0.1-0.3] P<0.01), 0.11 ([95% CI, 0.03-0.20] P=0.01), and 0.0004 ([95% CI, -0.0001 to 0.0014] P=0.3), all likely not clinically significant. Central and brachial SBPs of 112 mm Hg (95% CI, 111.2-114.1) and 121 mm Hg (95% CI, 120.2-121.9) were identified as optimal BP thresholds. In conclusion, central BP measured with a type I device is statistically but likely not clinically superior to brachial BP in a general population without prior cardiovascular disease. Based on the risk of major adverse cardiovascular events, the optimal type I central SBP appears to be 112 mm Hg.