Crystalloid vs colloid for Hemodynamics during Anesthesia INduction in TAVR patients (CHAIN-T): study protocol for a randomized controlled trial

To assess whether preload with colloids could reduce hypotension during induction in patients undergoing transcatheter aortic valve replacement (TAVR) compared to crystalloids. This study is a single-center, prospective, randomized, double-blind, parallel-controlled trial conducted at Xijing Hospital. A total of 116 patients scheduled for elective TAVR under general anesthesia will be randomly assigned in a 1:1 ratio to either the colloid group or the crystalloid group, receiving either 5 ml/kg of colloid or crystalloid solution before anesthesia induction infused over 15 min. The primary outcome is the area under curve (AUC) of the change in mean arterial pressure (MAP) from baseline during the induction period (until 15 min after induction). Secondary outcomes include the incidence of intraoperative hemodynamic instability, the use of intraoperative vasoactive drugs, the Sequential Organ Failure Assessment (SOFA) score on the first postoperative day, postoperative hospital length of stay, the rate of intensive care unit (ICU) admission postoperatively, all-cause mortality during hospitalization and by 30 days after surgery, and the incidence of renal replacement therapy by 30 days after surgery. The results of this study will provide evidence on optimizing fluid preload to prevent hypotension during induction, reduce postoperative complications, and enhance recovery for patients undergoing TAVR. The findings are expected to promote anesthesia protocols in this patient population. The study protocol and statistical analysis plan were approved by the institutional Ethics Committee of Xijing Hospital, Fourth Military Medical University (XJLL-KY-20252560). The study was registered in ClinicalTrials.gov (NCT07329660) on December 29, 2025.