Impaired systemic microvascular function in patients with resistant arterial hypertension and microalbuminuria: an observational study

• Published in: European heart journal Vol. 45; no. Supplement_1
• Main Authors: Crahim, V, Lorenzo, A, Fernandes, V, Verri, V, Tibirica, E
• Format: Journal Article
• Language: English
• Published: 28.10.2024
• ISSN: 0195-668X; 1522-9645
• DOI: 10.1093/eurheartj/ehae666.2512

Abstract Background Systemic arterial hypertension (SAH) is one of the most prevalent diseases worldwide and is known to be associated with alterations of microvascular function. It is well known that microalbuminuria (MAU) is considered an early marker of renal and cardiac injury in SAH and is an independent risk factor for cardiovascular events in this population. Additionally, it is associated with altered endothelial function, which occurs from the early stages and can be considered an early marker. In some cases, SAH presents as resistant arterial hypertension (RAH), resulting in a worse prognosis compared to individuals with non-resistant hypertension. Moreover, MAU is associated with higher mortality, independent of glomerular filtration rate. Endothelial dysfunction is also a risk marker found in different conditions and can add to MAU in patients with RAH. Purpose To investigate systemic microvascular function in patients with RAH, with or without MAU. Methods 64 patients with RAH, of both genders (50% men), were evaluated, with 32 having MAU and 32 without MAU (defined as a urinary albumin/creatinine ratio between 30 and 300 mg/g in a routine urine sample). Microvascular function assessment was performed using a laser speckle system, allowing analysis of cutaneous microvascular flow. Flow measurements were expressed in arbitrary perfusion units (APU) divided by the mean arterial pressure to obtain cutaneous vascular conductance (CVC). A post-occlusive reactive hyperemia (PORH) test was performed, with brachial artery occlusion using a sphygmomanometer 50 mmHg above systolic pressure for 3 minutes; cutaneous flow was measured after release of the occlusion. Results Patients with or without MAU did not differ in terms of age, frequency of diabetes, and chronic kidney disease. The peak CVC values during PORH were 0.64 ± 0.15 and 0.55 ± 0.15 APU/mmHg in RH and RH + MAU patients, respectively (P=0.03). The delta values (peak – baseline) during PORH were 0.31 ± 0.11 and 0.25 ± 0.09 APU/mmHg in RH and RH + MAU patients, respectively (P=0.04)(Figure 1). Conclusions PORH-induced vasodilation was found to be reduced in patients with RAH and MAU compared to patients without MAU. This finding shows alteration of endothelium-dependent vasodilation mechanisms in these patients, indicating reduced systemic microvascular endothelial function. Endothelial dysfunction may be associated with glomerular permeability changes, contributing to MAU and further increasing the risk for these patients. This suggests the need for more intensive therapeutic interventions and better risk stratification for these patients, as endothelial dysfunction can be found in the early stages of the disease.Figure 1