NON-INVASIVE MAPPING OF POST-PANCREATICODUODENECTOMY GASTRIC FUNCTION USING GASTRIC ALIMETRY®
Tim Hsu-Han Wang*1, Stefan Calder2, Armen A. Gharibans2, Gabriel Schamberg2, Sanket Srinivasa1,3, Sanjay Pandanaboyana4,5, Keno Mentor4, Greg O'Grady1,2
1The University of Auckland Faculty of Medical and Health Sciences, Auckland, Auckland, New Zealand; 2Alimetry Ltd, Auckland, New Zealand; 3North Shore Hospital, Auckland, Auckland, New Zealand; 4Freeman Hospital, Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom; 5Newcastle University, Newcastle upon Tyne, Tyne and Wear, United Kingdom
Introduction
Pancreaticoduodenectomy (PD) is performed for several indications, including pancreatic and biliary malignancies. A common post-operative complication is delayed gastric emptying (DGE), which may occur acutely and/or chronically. Procedural variations have sought to reduce the incidence of DGE and its associated symptoms of nausea, vomiting and fullness, however the underlying pathophysiology is still poorly understood. Emerging evidence suggests that gastric myoelectrical abnormalities may contribute to DGE. A non-invasive medical device for body surface gastric electrical mapping was recently developed to evaluate gastric electrical activity and function. This study aimed to assess the feasibility of the novel device on the stomach following PD, to identify any changes in gastric activity and their correlation with symptoms.
Methods
PD patients from Auckland, New Zealand between 2017-2022 were recruited. Patients with known mechanical obstructions or recurrent malignancies were excluded. The Gastric Alimetry System® (Auckland, New Zealand) was employed, comprising a stretchable array (8x8 electrodes; 196cm2) and cloud-based analytics platform. Following an overnight fast, 30 minutes of baseline recording was performed, followed by a meal challenge and 4 hours of post-prandial recordings. Symptoms were logged on a validated iPad App. Spectral analysis of Gastric Alimetry data was performed, with quantitative analysis including Principle Gastric Frequency, BMI-adjusted amplitude and Gastric Alimetry Rhythm Index (GA-RI, a measure of rhythm stability), compared to reference intervals from 110 healthy volunteers. Adverse events were recorded.
Results
16 patients were recruited; all had a pylorus-resecting PD with 15/16 having a gastroejejunostomy and 1/16 receiving a Roux-en-Y reconstruction. Gastric Alimetry spectral abnormalities were more common in patients with moderate-severe symptom burdens (3/5 patients) vs mild-minimal symptom burdens (1/11); p=0.029. Abnormalities in symptomatic patients encompassed low GA-RI in 2 patients (<0.25); and low amplitude in 1 patient (<22μV) indicating gastric neuromuscular dysfunction. Gastric Alimetry symptom phenotypes in symptomatic patients were variable; sensorimotor (3), post-gastric (2) and continuous (2); (2 having mixed profiles). There were no adverse events.
Conclusion
Gastric Alimetry is a safe and feasible technique to non-invasively assess gastric function following PD. A third of patients had moderate to severe gastric symptoms chronically after PD, and these showed a higher rate of gastric neuromuscular dysfunction. A range of symptom phenotypes were noted, indicating gastric sensory, post-gastric (i.e. dumping) and continuous (likely neuropathic) contributions. These data indicate a role for Gastric Alimetry testing in evaluating the causes of chronic gastric symptoms after PD.
Figure 1 A. Array placement on patient's abdomen. B. Validated iPad App for simultaneous symptom logging. C. Example from a patient with no symptoms and normal gastric slow wave characteristics. D. Example from a symptomatic patient with abnormal gastric rhythm stability.
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