Relationship between 24-h Ambulatory Blood Pressure Variability and Degree of Renal Artery Stenosis in Hospitalized Patients with Hypertension

Background: Blood pressure variability (BPV) is a critical risk factor for cardiovascular outcomes and is associated with atherosclerotic renal artery stenosis (ARAS), which is diagnosed using digital subtraction angiography (DSA). However, the relationship between the degree of renal artery stenosis (d-RAS), diagnosed using renal artery contrast-enhanced ultrasound (CEUS), and 24-hour ambulatory BPV in hospitalized patients with ARAS remains unclear. Methods: Hospitalized hypertensive patients were divided into ARAS and non-ARAS groups based RAS diagnoses using CEUS. The ARAS patients were further classified into unilateral and bilateral categories. Quantification of BPV over 24 hours, daytime, and nighttime utilized standard deviation (SD), coefficient of variation (CV), and average real variability (ARV). Percentage stenosis was used to evaluate d-RAS. Pearson's and multivariate beta regression analyses were used to assess correlations between BPV and d-RAS. Results: We found that 24-hour systolic BPV (SBPV), presented as SD, CV, and ARV indices, was positively correlated with unilateral d-RAS (R-1 = 0.460, p = 0.001; R-1 = 0.509, p < 0.001; R-1 = 0.677, p < 0.001, respectively). This correlation was consistent with the daytime SBPV (R-1 = 0.512, p < 0.001; R-1 = 0.539, p < 0.001; R-1 = 0.678, p < 0.001, respectively) and daytime diastolic BPV (DBPV) (R-1 = 0.379, p = 0.010; R-1 = 0.397, p = 0.007; R-1 = 0.319, p = 0.033, respectively). Similarly, 24-hour DBPV assessed by SD and CV also correlated positively with unilateral d-RAS (R-1 = 0.347, p = 0.019; R-1 = 0.340, p = 0.022, respectively), as did nighttime SBPV assessed by ARV indices (R-1 = 0.415, p = 0.005). No significant correlations were found between BPV and bilateral d-RAS (p > 0.05). Multivariate beta regression analysis indicated that 24-hour SBPV (odds ratio [OR] = 1.035, 95% confidence interval [CI]: 1.054-1.607, p = 0.035) and daytime SBPV (OR = 1.033, 95% CI: 1.004-1.061, p = 0.023; both evaluated via AVR) were independent risk factors for d-RAS. Conclusions: SBPV is positively correlated with unilateral d-RAS at all time points. Both 24-hour and daytime SBPV (evaluated using ARV indices) were identified as independent d-RAS risk factors.