Visible light spectrography should be used in diagnosing chronic gastrointestinal ischemia

In this study from the Netherlands, the authors used visible light spectroscopy (VLS) to diagnose chronic gastrointestinal ischemia (CGI) and to predict its response to surgical or endoscopic treatment; a challenging task indeed. Diagnosis of CGI is difficult because the classic symptom complex of meal-precipitated abdominal pain leading to weight loss is nonspecific; asymptomatic splanchnic vascular obstruction is not uncommon in the general population with autopsy series showing significant stenosis of the celiac, superior mesenteric, and inferior mesenteric arteries of 50%, 30%, and 30%, respectively; radiologic imaging tests conventionally used to diagnose CGI evaluate only vascular anatomy and not physiologic parameters of ischemia, i.e., intracellular acidosis (which can be evaluated by balloon tonometry) nor mucosal hemoglobin oxygen saturation, which is determined by VLS.

The authors evaluated 212 patients referred for suspected CGI and in all performed radiologic imaging of the splanchnic vessels and assessment of mucosal perfusion by VLS. Obstructive CGI (OCGI)was diagnosed by a multidisciplinary team and required clinical agreement, significant stenosis of at least one splanchnic artery and mucosal ischemia as determined by VLS. OCGI was classified as single- or multivessel and patients were offered surgical or endovascular revascularization. Response to treatment was then evaluated in patients with OCGI. A total of 107 patients were diagnosed with OCGI and data on response to treatment was available in 89 with a median follow-up of 13 months. Sustained symptomatic response was seen in 62 (70%) and most strongly predicted by the presence of weight loss, an abdominal bruit, and a gastric corpus mucosal saturation level of < 56%. This is an important study because it stresses the value of a team approach to diagnosis and the use of a combination of techniques to evaluate vascular obstruction and its functional significance.

There were several shortcomings of the study, in my opinion, although these do not lessen the importance of the study’s message. Most important, the study was not blinded. Spontaneous resolution of symptoms was noted in 19 patients without OCGI and in an additional 9 patients treated with a variety of medical and surgical means. Celiac artery compression release relieved symptoms in 17 patients, although the ischemic nature of this entity is arguable. Repeat VLS was not performed in all patients. Finally, clinical follow-up was relatively short and long-term follow-up was mainly by questionnaire, leading to another source of bias. To perform fiber-optic catheter-based VLS oximetry during esophagogastroduodenoscopy in a consistent fashion is technically challenging but probably worthwhile to learn. The authors continue to shine light on this relatively dark and poorly illuminated subject matter; let it shine, let it shine, let it shine.

Dr. Lawrence J. Brandt, MACG, AGAF, FASGE, is a professor of medicine and surgery at the Albert Einstein College of Medicine, N.Y., and emeritus chief, division of gastroenterology, Montefiore Medical Center, Bronx, N.Y.