Use of real-time near-infrared fluorescence to assess gastric viability in dogs with gastric dilatation volvulus: A case-control study.

Objective: To describe near-infrared fluorescence (NIRF) for assessment of gastric viability and describe NIRF's influence on the surgeon's operative strategy in dogs with gastric dilatation and volvulus (GDV).

Study design: Prospective clinical trial.

Animals: Twenty dogs with GDV and 20 systemically healthy dogs.

Methods: Following gastric derotation, the surgeon's subjective assessment of gastric viability was recorded prior to near-infrared imaging. Changes in the surgeon's initial assessment of viability based on the visual pattern of gastric fluorescence was recorded. If nonviable (lack of defined vessels), a partial gastrectomy was performed and submitted for histopathology. The stapled gastrectomy line was imaged. Viable (defined vessels) and nonviable fluorescence intensities were compared with healthy dogs undergoing surgery for nongastrointestinal disease.

Results: Subjective assessment diagnosed 17 viable and three nonviable GDVs (2 fundi; 1 cardia). Near-infrared imaging demonstrated nonviable gastric fluorescence in 4 dogs (3 fundi/cardia; 1 fundus). The surgeon's margins for resection were altered in 3/20 dogs. Fluorescence intensity (cardia, fundus, body, pylorus) was lower in GDV viable (30.59%, p = .04; 38.17%, p < .01; 51.18%, p < .01; 44.12%, p= .01) and nonviable (11.00%, p < .01; 4.33%, p < .01; 57.67%, p = .22; 54.33%, p = .72) dogs compared to healthy controls (44.7%, 70.05%, 84.00%, 63.95%). Fundic fluorescence was less in nonviable gastric tissue in comparison with viable gastric tissue (p = .03). Fluorescence of the gastrectomy staple line approximated that of viable tissue.

Conclusion: Near-infrared fluorescence can identify histologically confirmed nonviable gastric tissue.

Clinical significance: These results provide enough evidence to support the implementation of NIRF as an adjunct to gross examination of the gastric wall in dogs with GDV.