Abstract P256: Structural Alterations of Subcutaneous Small Resistance Arteries in Resistant Hypertension

Abstract

Background: It is was suggested that, in resistant hypertension, the presence of particularly pronounced microvascular alterations may contribute to explain the relative lack of response to treatment Patients and Methods: We investigated a population of 94 treated essential hypertensive patients. Secondary forms of hypertension were excluded, and in all patients a 24-hour blood pressure monitoring was performed in order to exclude a white coat effect. In all patients, we evaluated small resistance arteries morphology by a wire micromyographic approach. Subcutaneous tissue was obtained by local biopsy or during election surgery and subcutaneous small resistance arteries were dissected and mounted on a myograph; the media to lumen ratio (M/L) was then measured. We subdived our patents according to the presence or not of resistant hypertension (clinic blood pressure values above 140/90 mm Hg despite administration of three antihypertensive agent including a diuretic and 24-hour blood pressure values >130/80 mm Hg). Sixteen patients had true resistant hypertension, and were compared with the remaining 78 patients with non-resistant hypertension. Results: are summarized in the Table, The two groups were also different in terms of mean age (57±12 vs. 67±7 years, p=0.016 and pulse pressure/stroke volume, a rough index of large artery distensibility: 0.63±0.31 vs. 0.90±0.33, p=0.02). Conclusion: Hypertensive patients with true resistant hypertension have greater microvascular structural alterations compared with non-resistant hypertensive patients. This could partly explain the resistance to treatment and the high cardiovascular risk observed in these patients.