PP.25.08] THERAPEUTIC DRUG MONITORING IN RESISTANT HYPERTENSIVES PREVIOUSLY TREATED WITH INVASIVE APPROACHES

Abstract

Objective: Renal denervation (RDN) and baroreflex activation therapy (BAT) are invasive therapeutic approaches for resistant hypertension (RH), indicated when antihypertensive drug therapy is inefficacious. Several reports have found an unsatisfactory response to these approaches; one of the factors called upon to account for the failure of these devices is the lack of therapeutic adherence. The aim of this study was to retrospectively evaluate the therapeutic adherence, using an objective assessment as the therapeutic drug monitoring (TDM), in a group of patients who have undergone invasive approach in previous years, either RDN or BAT, and correlate it with the answer to the invasive procedure. Design and method: We retrospectively analysed 12 patients with RH (9 females). Before performing invasive procedure, all patients were considered adherent according to the physician intuition and the answers given to the Morisky questionnaire. Serum TDM, by Ultra High Performance Liquid Cromatography (UHPLC) method, was done during a routine follow up visit, after at least one year from the last invasive approach. A clinical response to invasive approaches was considered as a reduction in 24 h Ambulatory Blood Pressure Monitoring (ABPM) systolic blood pressure (SBP) of at least 10 mmHg at 12 months from the procedure. Patients were considered adherents (AD) if all the prescribed drugs were found or only one was not found; patients were considered non-adherents (NAD) if none of the prescribed drugs were found. Results: 4 patients were AD and 8 NAD. In the whole sample a clinical response was found in 41% of the patients. Among AD the clinical response rate was 75%, whilst among NAD the clinical response rate dropped to 25%. No significant clinical and social differences were found between NAD and AD, but NAD had significant higher office SBP and 24 h ABPM SBP than AD (p < 0.05). Conclusions: Lack of therapeutic adherence is associated to a limited clinical efficacy of invasive approaches in apparent RH. Our data underlines the importance of adherence therapeutic evaluation before and after performing invasive procedures, whose effectiveness can be undermined by poor therapeutic adherence.