Association of Ambulatory Arterial Pressure Index with Circadian Blood Pressure Patterns in Patients with Primary Hypertension and Coronary Artery Disease.

Background: Disruption of circadian blood pressure (BP) rhythms-manifested as non-dipper or reverse-dipper patterns-is associated with increased cardiovascular risk, especially in patients with primary hypertension (PH) and concomitant coronary artery disease (CAD). The ambulatory arterial pressure index (AAPI), a novel parameter derived from 24-hour ambulatory BP monitoring (ABPM), reflects the cumulative hemodynamic burden and may provide insight into circadian BP abnormalities. However, its relationship with BP rhythm patterns in this high-risk population remains unclear. Methods: This retrospective observational study included 430 hospitalized patients with PH and CAD who underwent 24-hour ABPM between January 2022 and December 2023. Patients were classified into dipper (n = 51), non-dipper (n = 266), and reverse-dipper (n = 113) groups based on the nocturnal decline in systolic BP. AAPI was calculated as the ratio of diastolic to systolic pressure load over a 24-hour period. Baseline demographic, biochemical, and hemodynamic variables were compared across groups, and correlations between AAPI and BP rhythm categories were analyzed. Results: The mean age was 69.1 ± 17.8 years, and 63.5% of patients were male. There were no significant differences in age, sex, renal function, or lipid profiles across circadian BP rhythm subgroups. Patients with disrupted BP rhythms (non-dipper or reverse-dipper) had significantly higher AAPI values than those with a dipper pattern (0.396 ± 0.041 vs 0.387 ± 0.043, Conclusion: AAPI is significantly associated with abnormal circadian BP patterns in patients with PH and CAD. As a simple, integrative hemodynamic index, AAPI may aid in the early identification of patients with rhythm disruption and provide added value for personalized cardiovascular risk stratification.