Damage to peripheral arteries by the atherosclerotic process accounts for about 3% of the world's population, which puts this problem in the category of major social problems. Modified lipoproteins and cholesterol crystals are known to accumulate in the arterial intima and cause the formation of proatherogenic macrophages, foam cells, and inflammation. Defective efferocytosis of apoptotic foam cells leads to the formation of a necrotic core, a sign of failure to resolve inflammation. Resolution of inflammation is mediated by specialized pro-resorption lipid mediators, proteins and signaling gases. Improving the balance between pro-inflammatory and anti-inflammatory factors contributes to the reverse development of local atherogenesis. Active direct intervention in the reconstruction of the adventitial layer of the arterial wall using cholesterol-affinity polysaccharide hydrogels containing a cocktail of growth factors creates conditions for the formation of additional extracellular matrix and reversal of cholesterol mass from the subintimal zone. Creating concentration and electrostatic gradients in the adventitia zone using a hydrogel may be one of the effective ways to degrade early soft atherogenic plaques and locally restore the damaged structure of the vessel wall. Growing scientific interest in the previously insufficiently studied adventitia indicates its important role in angionesis and atherogenesis.

Background. Infected pseudocysts and infected walled-off necrosis (WON) are severe complications of acute pancreatitis associated with high mortality rates (up to 35%) following open surgery. The use of lumen-apposing metal stents (LAMS) enables minimally invasive endoscopic drainage; however, data on the dynamics of laboratory inflammatory markers and cavity regression during staged endoscopic debridement remain insufficient. Aims — to evaluate the efficacy and safety of transmural drainage using LAMS followed by staged endoscopic debridement and necrosectomy in patients with infected pseudocysts and infected walled-off necrosis. Methods. A prospective observational single-center study was conducted from January 2019 to March 2025. A total of 43 patients with infected pseudocysts or infected walled-off necrosis were enrolled. All patients underwent endoscopic ultrasound-guided transmural drainage with a 10-mm LAMS, followed by staged debridement for infected pseudocysts and staged necrosectomy for infected walled-off necrosis. The primary outcomes were the dynamics of C-reactive protein (CRP) levels and cavity volume. Statistical analysis was performed using the Wilcoxon signed-rank test. Results. Median CRP decreased from 132.7 (53.1; 190.2) mg/L at admission to 43.6 (14.8; 76.1) at discharge (p 0.001). Cavity volume decreased from 344.8 (88.9; 830.2) to 11.2 (5.3; 16.4) cm³ (p 0.001), representing a regression of 94.2%. A total of 30 adverse events were recorded, with hyperthermia being the most common (20 cases, 66.7% of all complications). Life-threatening complications (cyst perforation, erosive bleeding) required laparotomy in 5 patients (11.6%). Mortality was 2.3%. In patients with ineffective endoscopic treatment, the initial cavity volume exceeded 1000 mL and sequestrum size exceeded 5 cm. Conclusions. Endoscopic transmural drainage with LAMS and staged debridement effectively controls inflammation and achieves almost complete cavity regression in patients with infected pseudocysts and infected walled-off necrosis. In cases with cavity volume 1000 mL and large sequestra ( 5 cm), combined drainage techniques (percutaneous drainage, video-assisted retroperitoneal debridement) should be considered.