Highly viscous ascites prompting reconsideration of cardiorenal syndrome in a patient with advanced CKD after TAVI.

Volume management is challenging in patients with advanced chronic kidney disease (CKD) complicated by cardiovascular disease, particularly when systemic congestion cannot be explained solely by cardiac or renal dysfunction. We report an elderly man with type 2 diabetes mellitus, stage 4 CKD, hypertension, and ischemic heart disease who developed refractory pleural effusion, ascites, and peripheral edema after transcatheter aortic valve implantation (TAVI). Right heart catheterization showed preserved cardiac output, whereas echocardiography suggested right-sided pressure overload and systemic venous congestion. Intensified diuretic therapy led to partial body weight reduction but was accompanied by worsening renal function, and adequate volume control remained difficult. Although ascites was initially attributed to cardiorenal syndrome or liver disease, diagnostic paracentesis revealed highly viscous, protein-rich ascitic fluid with a low serum-ascites albumin gradient and a markedly elevated carcinoembryonic antigen level. In conjunction with non-contrast magnetic resonance imaging findings showing multiple loculated cystic collections and fluid-fluid levels, these ascitic fluid characteristics raised suspicion of a mucinous peritoneal process suggestive of pseudomyxoma peritonei, despite negative cytology. Recurrent deterioration of renal function was temporally associated with the reaccumulation of massive ascites, whereas right-sided venous congestion may have acted as an aggravating hemodynamic factor. This case highlights the importance of evaluating atypical ascitic fluid characteristics and considering etiologies beyond cardiac, renal, or hepatic dysfunction in patients with refractory volume overload after TAVI.