CESORCenter for Emergency Surgery Outcomes Research
SnapChole
Management strategies and outcomes in acute calculous cholecystitis.
SnapChole is an international, time-bound prospective platform study of acute calculous cholecystitis that characterizes pathway selection, source-control strategy, and 90-day outcomes under real-world emergency surgical conditions. In severe disease, the platform embeds prespecified target trial emulations so competing strategies can be compared from a clearly defined decision point rather than after treatment pathways diverge.
Leadership and governance
Gary Alan Bass, MD, MSc, MBA, PhD, FICS, FEBS (Emergency Surgery)
Assistant Professor of Surgery and Assistant Professor of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania
gary.bass@pennmedicine.upenn.edu
Stefano P. B. Cioffi, MD, PhD
Niguarda Major Trauma Hospital, Milan
Stefanopbcioffi@gmail.com
Lewis J. Kaplan, Matthew J. Lee, Nandita Mitra, Dane Isenberg, Hayato Kurihara, and Isidro Martínez-Casas contribute scientific, statistical, and multicenter oversight.
SnapChole is conducted with ESTES, ASGBI, SIS-NA, and SIS-E collaboration to support international participation.
Why this study exists
Acute calculous cholecystitis is common, but severe disease is where strategy selection becomes most consequential. Patients may be assigned to early cholecystectomy, drainage-first, or antimicrobial-only management under superficially similar decision contexts, yet those decisions are shaped by physiologic reserve, reversibility of organ dysfunction, diagnostic certainty, and system capability.
SnapChole addresses that problem. The study does not treat pathway selection as a retrospective coding exercise. It captures the attending surgeon–level decision point as time zero and preserves the variables needed to estimate the effect of source-control strategies in clinically coherent populations.
Primary outcome
DAOH90Days alive and out of hospital at 90 days
Time zero
Decision pointThe first attending surgeon–level decision at which competing strategies are feasible
Strategy 1
Early cholecystectomy vs drainage-firstStrategy 2
Drainage-first vs antimicrobial-onlyDesign
International multicenter prospective enrollment using a predefined 90-day local accrual window with standardized contemporaneous data capture.
The target trial emulations are restricted to adults with Tokyo Guidelines 2018 Grade III acute calculous cholecystitis in whom competing strategies are simultaneously feasible.
Eligibility, assignment, time zero, grace period, follow-up, and estimands are specified before analysis to reduce immortal time bias and post-baseline selection.
Beyond the core causal analyses, the platform supports benchmarking, PROMs, surgeon decision-making work, and implementation-oriented pathway development.
Nested target trial emulations
TTE1
TTE2
Implementation is part of the design. The platform is intended not only to produce interpretable estimates, but to translate them into a decision-aligned clinical pathway and implementation toolkit for routine emergency surgical workflows.
Additional work packages include patient-reported outcomes, surgeon decision-making under uncertainty, and contextual analysis of institutional constraints that shape pathway assignment in real practice.
For participating centers and collaborators
SnapChole is for centers able to support consecutive prospective case ascertainment, standardized data collection, and protocol-aligned follow-up using routine clinical data. Methodologic collaborators, analysts, and implementation scientists are considered through CESOR participation pathways.
For participating centers
Centers interested in participation should contact the study leadership and submit structured intake through CESOR.
For analysts and collaborators
Collaborators with relevant methodological, statistical, implementation, or emergency surgery expertise should review CESOR participation pathways before initial outreach.
Authorship and contributorship
Primary and subsidiary manuscripts follow an ICMJE-aligned, contribution-based authorship framework with CRediT role reporting and collaborative-group acknowledgement for eligible site contributors.