In recent years, research has emphasized the significance of mild clinical and biochemical presentations of primary aldosteronism (PA) that do not meet current diagnostic criteria of the syndrome. In this study, we assessed the prevalence of autonomous aldosterone (Ald) secretion (AAS), defined as a positive (>1.2 ng/dL/mIU/L) Ald-to-renin ratio (ADRR) combined with unsuppressed Ald (>4 ng/dL), and its associations with blood pressure (BP), cardiac function, and common carotid artery (CCA) intima-media thickness (IMT) in patients with incidentally discovered adrenal adenomas (AI), who were either normo- or hypertensive but had no other cardiovascular disease. Among 332 AI patients hospitalized between November 2018 and December 2019, 63 study participants were recruited (26 normo- and 37 hypertensive), who underwent hormonal examinations, 24 h ambulatory BP measurement, transthoracic echocardiography, and CCA IMT assessment without altering chronic medications. AAS was found in approximately 25% of subjects (seven normo- and nine hypertensive); urinary aldosterone excretion (UAldE) exceeded 10 ug/day in none of the subjects. The left ventricular mass index correlated positively with UAldE in non-diabetic patients (n = 50), and negatively with renin in those without beta blocker therapy (n = 38). The study shows that a pragmatic approach to hormonal assessment (no chronic therapy modification) may reveal patients with AAS. Screening for this subclinical PA presentation is probably more effective with a permissive ADRR than UAldE in such a setting.