Use of T-stat to Predict Pelvic Ischemia during and after Endovascular Aneurysm Repair

Objectives: As surgeons become more aggressive in treating aneurysmal disease with endovascular techniques, essential surgical principles of preserving hypogastric arteries and inferior mesenteric artery (IMA) circulation have been challenged. A case where the successful use of an FDA-approved device, the T-Stat, allowed successful endovascular aneurysm repair (EVAR) in a patient at high risk for pelvic and colon ischemia.
Methods: A 70-year-old man was treated with an end-to-end aortobifemoral graft 20 years ago. Upon recent examination, a 5.4-cm infra-renal abdominal aortic aneurysm with a large, patent IMA and occluded hypogastric arteries bilaterally were found. The bifurcated graft was placed below the renal arteries and IMA. Celiac and superior mesenteric arteries had a greater than 70% stenosis by duplex criteria. The patient had a T-Stat Optical Sensor placed in the recto-sigmoid to measure colon mucosal oxygen saturation (CMOS) while a diagnostic angiogram allowed IMA selection and balloon occlusion for 15 minutes.
Results: No decrease in CMOS levels in the recto-sigmoid were found. Subsequently, the patient underwent an EVAR with complete exclusion of the IMA. No change in the CMOS was identified during the case. Post-operatively, the patient demonstrated no signs of pelvic or colon ischemia.
Conclusions: The FDA-approved device, T-Stat accurately predicted colon ischemia during this high risk endovascular procedure where concerns over colon ischemia can be tracked in real time. This allowed the patient to choose between an open aneurysm repair with re-implantation of the IMA or an EVAR with knowledge pre-operatively that the likelihood of pelvic ischemia was low.