Lower Systolic Blood Pressure and Cardiovascular Event Risk Stratified by Renal Resistive Index in Hospitalized Cardiovascular Patients: J-VAS Study

BACKGROUND The threshold of blood pressure (BP) reduction in cardiovascular patients is debatable due to the J-shaped curve phenomenon, which is particularly observed in patients with increased arterial stiffness. The renal resistive index (RRI) correlates well with systemic arterial stiffness; therefore, we aimed to demonstrate the role of RRI in guiding the choice of optimal BP. METHODS A retrospective analysis of prospectively collected data of the hospitalized cardiovascular patients at Jichi Medical University Hospital. All patients had the RRI measurement performed and were assigned to a higher (RRI ≥ 0.8) or lower RRI group. Each group was subdivided by quartiles of the BP at discharge. The primary endpoints were fatal and nonfatal cardiovascular events, including heart failure, acute coronary syndrome, acute aortic disease, acute arterial occlusion, and stroke. RESULTS The mean follow-up period was 1.9 years (3,365 person-years), n = 1,777 (mean age 64.7 years). There were 252 cardiovascular events occurred, 24.0% and 12.2% in the higher and lower RRI populations, P < 0.001. In the higher RRI group, the lowest systolic BP (SBP) quartile (<105 mm Hg) was a risk factor for cardiovascular events when compared with the highest SBP quartile (≥130 mm Hg; adjusted hazard ratio, 2.42; 95% confidence interval, 1.17-5.03; P = 0.017). A 1 SD decrease of SBP (17.5 mm Hg) was associated with a 25% increase in the risk of cardiovascular events. In the lower RRI group, these associations were not observed. CONCLUSIONS Lower SBP at discharge was associated with a risk of cardiovascular events in the hospitalized cardiovascular patients with RRI ≥ 0.8.