SAT-056 Primary Aldosteronism Has a Distinctive Twenty-four Hour Blood Pressure Profile

Background: Primary aldosteronism (PA) has a reported prevalence of up to 30% in cases of resistant hypertension and is associated with worse cardiovascular outcomes than BP-matched essential hypertension (EH), but is substantially under-diagnosed due to the lack of specific symptoms and signs. Ambulatory blood pressure monitoring (ABPM) provides a non-invasive method for evaluating circadian BP variations, offers valuable prognostic information and may help to differentiate PA from EH in patients referred with non-specific hypertension for investigation. Aims: To compare AMBP parameters in hypertensive patients with established PA and those without, and correlate these parameters with cardiovascular outcomes. Methods: AMBP readings were evaluated retrospectively in 453 patients assessed at Monash Heart (the largest cardiology service in Victoria, Australia). Patient demographics, screening aldosterone and renin concentrations and medications were retrieved from medical records. 414 hypertensive patients with presumed EH and 39 PA patients were identified and their cardiovascular events (myocardial infarction, left ventricular hypertrophy, coronary artery disease, atrial fibrillation) were recorded. All parameters are reported as the median [interquartile range], unless stated otherwise. Statistical significance was set at p<0.05. Results: Compared to hypertensive patients who are presumed to have EH, PA patients were significantly younger (55 yr [50, 66] vs 63 yr [53, 72]), had higher systolic (149 mmHg [134, 156] vs 133 mmHg [124, 145]) and diastolic BP readings (87 mmHg [82, 92] vs 75 mmHg [68, 82]) with similar patterns observed for average daytime and night-time BP. BP load (% daytime and night-time SBP/DBP readings over 135/85 and 120/70 mmHg, respectively) was significantly higher for both systolic and diastolic in PA (83% [61, 92] and 57% [35, 76]) compared with the non-PA group (48% [23, 75] and 14% [5, 35]). 77% of patients with PA (30/39) had loss of physiological nocturnal BP dipping compared with 44% of the non-PA group (184/414). Rates of cardiovascular events were similar in both groups but may be confounded by the retrospective nature of this study and lack of long-term follow-up. Conclusion: In our study, PA is associated with a distinctive 24-hour BP profile, including a significant increase in BP load and loss of nocturnal BP dipping which are known risk factors for adverse cardiovascular events. A prospective study is needed to better define AMBP parameters in PA and evaluate their ability to unveil underlying PA amongst hypertensive patients.