Influencing factors and hemodynamic study of initial and sustained orthostatic hypotension in middle-aged and elderly patients.

Orthostatic hypotension (OH) is a common autonomic disorder. This study aimed to investigate the influencing factors and hemodynamic mechanisms of initial and sustained OH in middle-aged and elderly patients. The authors analyzed the clinical characteristics and hemodynamic variables of patients aged ≥ 50 years according to the various forms of OH, diagnosed by an active orthostatic test using the CNAP monitor. The study included 473 participants; 119 (25.2%) patients had initial (54, 45.4%) or sustained (65, 54.6%) OH. Age, comorbidities, or medications did not differ significantly between the initial OH and non-OH groups. Sustained OH was associated with age and diabetes (p = .003 and p = .015, respectively). Hemodynamic analysis revealed higher cardiac output (CO) in the sustained OH group within 15 s than in the non-OH and initial OH groups (both p < .001); no difference in CO was observed between the initial OH and non-OH groups. The systemic vascular resistance (SVR) in both initial OH and sustained OH groups within 15 s was lower than that in the non-OH group (both p < .001). No differences in SVR at 3 min were observed between the initial OH and non-OH groups. The SVR at 3 min in the sustained OH group was significantly lower than in non-OH and initial OH groups (both p < .001). Age and diabetes emerged as the independent risk factors associated with sustained OH. Initial OH is associated with a mismatch of increase in CO and decrease in SVR. Sustained OH is mainly associated with sustained inadequate adjustment in SVR.