Endoscopic visible light spectroscopy: a new, minimally invasive technique to diagnose chronic GI ischemia

BackgroundThe diagnosis of chronic GI ischemia (CGI) remains a clinical challenge. Currently, there is no single simple test with high sensitivity available. Visible light spectroscopy (VLS) is a new technique that noninvasively measures mucosal oxygen saturation during endoscopy.ObjectiveTo determine the diagnostic accuracy of VLS for the detection of ischemia in a large cohort of patients.DesignProspective study, with adherence to the Standards for Reporting of Diagnostic Accuracy.SettingTertiary referral center.PatientsConsecutive patients referred for evaluation of possible CGI.InterventionsPatients underwent VLS along with the standard workup consisting of evaluation of symptoms, GI tonometry, and abdominal CT or magnetic resonance angiography.Main Outcome MeasurementsVLS measurements and the diagnosis of CGI as established with the standard workup.ResultsIn 16 months, 121 patients were included: 80 in a training data set and 41 patients in a validation data set. CGI was diagnosed in 89 patients (74%). VLS cutoff values were determined based on the diagnosis of CGI and applied in the validation data set, and the results were compared with the criterion standard, resulting in a sensitivity and specificity of VLS of 90% and 60%, respectively. Repeated VLS measurements showed improvement in 80% of CGI patients after successful treatment.LimitationsSingle-center study; only 43% of patients had repeated VLS measurements after treatment.ConclusionsVLS during upper endoscopy is a promising easy-to-perform and minimally invasive technique to detect mucosal hypoxemia in patients clinically suspected of having CGI, showing excellent correlation with the established ischemia workup.