SEX DIFFERENCES IN RENAL MICROCIRCULATION OF HYPERTENSIVE PATIENTS

Abstract

Objective: Arterial hypertension is associated with alterations in the morphology and function of the microvascular structure. Whether these changes are sex-specific in the kidney of hypertensive patients is unknown. Contrast-enhanced ultrasonography (CEUS) enables the quantification of renal microcirculation. The objective of this study was to compare the cortical microcirculation in hypertensive (HT) women versus HT men, and assess the response to a cold pressure test (CPT). Design and method: This was a prospective observational study. Hypertensive (HT) participants underwent two separate CPT of 2 minutes. Doppler ultrasound was used to measure renal resistive index (RRI) and CEUS to measure the perfusion index (PI) as a proxy of renal tissue microcirculation. Renal Doppler and CEUS were performed before and during the CPT. We compared baseline renal measures and responses to CPT of HT women and HT men using a mixed analysis model. Results: Twenty-two HT men and eleven HT women were included. Age and body mass index were similar for both groups. Baseline RRI was similar in both genders, but HT women had higher baseline PI (median with interquartile range): 2344 U(1553-2685) vs 1264 U(591-1741), p = 0.007. The CPT did not affect the RRI in HT women and men. Overall the PI was higher in women (p = 0.006) and the PI increased during CPT (p<0.001), but there was no significant difference in the response to CPT between the genders (no interaction). Conclusions: Hypertensive women had a higher PI than hypertensive men, suggesting that microcirculation is better preserved in HT women compared to HT men. The increase in PI during the CPT is similar in both genders suggesting the absence of sex-specific reactivity of the microvasculature during CPT.