Citations

We provide the first longitudinal and most comprehensive analysis of the intrarenal microvasculature in a slowly progressive model of autosomal dominant polycystic kidney disease (ADPKD) and integrate the findings with studies in a young cohort of individuals with ADPKD. We identified vasculature-related pathways that could be targeted for therapeutic interventions and contribute promising, noninvasive biomarkers in patients with ADPKD. Alterations of the intrarenal microcirculation may affect drug delivery; a better understanding of its longitudinal changes may aid in treatment management.

Key Points The kidney microvasculature was quantified reliably in human autosomal dominant polycystic kidney disease early on, using super-resolution ultrasound localization microscopy. Microvascular parameters correlated with structural and functional indices, constituting promising biomarkers to evaluate noncystic parenchyma. Microvascular parameters may serve to assess disease severity and monitor progression from the early stages of the disease. Background In vitro studies in individuals with autosomal dominant polycystic kidney disease (ADPKD) have shown extensive intrarenal microvascular remodeling. However, analyses have been limited to the time of kidney failure because of the invasive nature of current methodologies to assess the intrarenal microvasculature. We hypothesized that super-resolution ultrasound microvascular imaging, known as ultrasound localization microscopy, enabled by high-framerate ultrasound imaging and microbubble localization and tracking postprocessing techniques, would safely, reliably, and reproducibly assess the intrarenal microvasculature in individuals with ADPKD at an early stage of the disease. Methods We prospectively enrolled young (<40 years of age), well-characterized, early-stage (eGFR >90 ml/min per 1.73 m 2 ) individuals with ADPKD, and sex–age 1:1 matched controls ( n =17 each) and assessed the intrarenal microvasculature using ultrasound localization microscopy. We determined the intersonographer reliability, intraobserver repeatability, and interobserver reproducibility of microvascular parameters in both groups, and the day-to-day variability in the control group. Microvascular parameters were correlated with structural (total kidney volume) and functional (eGFR) markers in individuals with ADPKD. Results Ultrasound localization microscopy provided a super-resolved map of the intrarenal microvasculature in ADPKD and matched controls. Intrarenal microvascular parameters ( e.g ., vessel density) were quantified in a safe, reliable (intraclass correlation coefficients, 0.96; 95% confidence interval, 0.91 to 0.98), reproducible (intraclass correlation coefficient, 0.96; 95% confidence interval, 0.93 to 0.98), and repeatable (coefficient of variations, 3.6%) manner. In control individuals, the day-to-day variability of most parameters was low, with coefficient of variation ranging from 1.8% to 10.7%. Microvascular parameters differed in individuals with ADPKD compared with controls, despite preserved eGFR. Interestingly, cortical vessel density and its derived perfusion correlated directly with eGFR, whereas tortuosity indices presented an inverse correlation. Conclusions Ultrasound localization microscopy provided a safe and reliable in vivo assessment of the human intrarenal microvasculature.

There is no clear consensus regarding the optimal approach for secondary prophylaxis of gastric variceal bleeding (GVB) in patients with cirrhosis. We conducted a systematic review and network meta‐analysis (NMA) to compare the efficacy of available treatments. A comprehensive search of several databases from each database's inception to March 23, 2021, was conducted to identify relevant randomized controlled trials (RCTs). Outcomes of interest were rebleeding and mortality. Results were expressed as relative risk (RR) and 95% confidence interval (CI). We followed the Grading of Recommendations Assessment, Development, and Evaluation approach to rate the certainty of evidence. We included 9 RCTs with 647 patients who had histories of GVB and follow‐ups >6 weeks. A total of 9 interventions were included in the NMA. Balloon‐occluded retrograde transvenous obliteration (BRTO) was associated with a lower risk of rebleeding when compared with β‐blockers (RR, 0.04; 95% CI, 0.01‐0.26; low certainty), and endoscopic injection sclerotherapy (EIS)–cyanoacrylate (CYA) (RR, 0.18; 95% CI, 0.04‐0.77; low certainty). β‐blockers were associated with a higher risk of rebleeding compared with most interventions and with increased mortality compared with EIS‐CYA (RR, 4.12, 95% CI, 1.50‐11.36; low certainty), and EIS‐CYA + nonselective β‐blockers (RR, 5.61; 95% CI, 1.91‐16.43; low certainty). Analysis based on indirect comparisons suggests that BRTO may be the best intervention in preventing rebleeding, whereas β‐blocker monotherapy is likely the worst in preventing rebleeding and mortality. Head‐to‐head RCTs are needed to validate these results.