Assessment of Pyloric Sphincter Physiology Using Functional Luminal Imaging Probe in Healthy Volunteers

EndoFLIP evaluation of the pylorus during minimal invasive Ivor-Levis esophagectomy

BACKGROUND/AIMS

During esophagectomy for malignancy, the anterior and posterior branches of the vagus nerve are transected in order to achieve surgical radicality. This leads to loss of central nervous system-control of the pylorus which may lead to delayed gastric emptying. We aimed to investigate the feasibility of the EndoFLIP technique for assessment of pyloric biomechanical properties in patients undergoing esophagectomy.

METHODS

A feasibility study in six patients undergoing surgery was conducted. EndoFLIP measurements were carried out preoperative (Pre-op), after surgical resection (Post-op) and following prophylactic balloon dilatation of the pylorus (Post-dil). By measuring the cross-sectional area and pressure of the pylorus the pyloric compliance and the incremental pressure-strain elastic modulus (Ep) were calculated.

RESULTS

Placing the catheter in the pyloric region was successfully achieved in all six patients. No complications were observed. Resection of the esophagus increased the incremental pyloric elastic modulus (Ep) from 0.59 ± 0.18 kPa to 0.99 ± 0.34 kPa (p = 0.03). After dilatation, the Ep was reduced to 0.53 ± 0.23 kPa (p = 0.04), which was close to Pre-op (p = 0.62). The pyloric compliance showed a similar pattern as that found for Ep.

CONCLUSION

The EndoFLIP system holds promise for assessment of biomechanics of the pyloric region in patients undergoing esophagectomy for cancer.

Interventional functional diagnostics in gastrointestinal endoscopy: Combining diagnostic and therapeutic tools in the endoscopy suite with the functional lumen imaging probe

With technical progress of gastrointestinal functional testing, there has been a demand for more comprehensive examination of esophageal physiology and pathophysiology beyond high-resolution manometry. A new interventional technology based on impedance planimetry, the functional lumen imaging probe (FLIP), enables intraluminal measurement of distensibility and compliance of hollow organs. EndoFLIP uses balloon catheters to measure diameter and distension pressure to calculate cross-sectional area and distensibility in different organs (mostly esophagus, stomach, anorectal region) and can be used in wide variety of indications (diagnostics, pre- and post-treatment evaluation) and currently serves as a helpful adjunctive tool in ambiguous clinical cases. EsoFLIP is a therapeutic variation that uses a stiffer balloon catheter allowing for dilation. The trend to simplify the clinical process from diagnosis to treatment tends to a one-session procedure combining diagnostics and therapeutic interventions. In specified conditions like e.g. achalasia or gastroparesis, a combination of EndoFLIP and EsoFLIP procedures may therefore be useful. The aim of this narrative review is to introduce the clinical use of FLIP and its potential benefit in combined diagnostic-therapeutic procedures.

Targeting the pylorus in gastroparesis: From physiology to endoscopic pyloromyotomy

BACKGROUND

The pylorus plays a key role in the control of gastric content outflow. Impairment of pyloric physiology has been observed in gastroparesis, particularly when associated with diabetes mellitus or opioid intake or after antireflux surgery. New tools have been developed to identify pyloric dysfunction in routine care, including functional luminal impedance planimetry (FLIP). As such, a new therapeutic strategy targeting the pylorus, namely endoscopic pyloromyotomy (G-POEM), has received increasing attention and emerged as a promising treatment for gastroparesis.

PURPOSE

The present review details the involvement of the pyloric pathophysiology in gastroparesis, as well as clinical results of G-POEM according to the current literature.

Using an Endoluminal Functional Lumen Imaging Probe (EndoFLIP™) to Compare Pyloric Function in Patients with Gastroparesis to Patients After Esophagectomy

BACKGROUND

Gastroparesis (GP) occurs in patients after upper gastrointestinal surgery, in patients with diabetes or systemic sclerosis and in idiopathic GP patients. As pyloric dysfunction is considered one of the underlying mechanisms, measuring this mechanism with EndoFLIP™ can lead to a better understanding of the disease.

METHODS

Between November 2021 and March 2022, we performed a retrospective single-centre study of all patients who had non-surgical GP, post-surgical GP and no sign of GP after esophagectomy and who underwent our post-surgery follow-up program with surveillance endoscopies and further exams. EndoFLIP™ was used to perform measurements of the pylorus, and distensibility was measured at 40 ml, 45 ml and 50 ml balloon filling.

RESULTS

We included 66 patients, and successful application of the EndoFLIP™ was achieved in all interventions (n = 66, 100%). We identified 18 patients suffering from non-surgical GP, 23 patients suffering from GP after surgery and 25 patients without GP after esophagectomy. At 40, 45 and 50 ml balloon filling, the mean distensibility in gastroparetic patients was 8.2, 6.2 and 4.5 mm²/mmHg; 5.4, 5.1 and 4.7 mm²/mmHg in post-surgical patients suffering of GP; and 8.5, 7.6 and 6.3 mm²/mmHg in asymptomatic post-surgical patients. Differences between symptomatic and asymptomatic patients were significant.

CONCLUSION

Measurement with EndoFLIP™ showed that asymptomatic post-surgery patients seem to have a higher pyloric distensibility. Pyloric distensibility and symptoms of GP seem to correspond.

Fasting pyloric diameter and distensibility by functional endoluminal imaging probe in unsedated healthy volunteers

BACKGROUND

Recent studies with functional endoluminal imaging probe (EndoFLIP® ) measure physiologic characteristics of the pylorus. EndoFLIP® has the potential to select optimal candidates for gastric peroral endoscopic myotomy (G-POEM). Normative values of the pylorus using EndoFLIP® have not been established.

METHODS

Twenty-four healthy volunteers (20-56 years old; 15 females) underwent unsedated, transoral EndoFLIP® measurements of the pylorus after 8 h of fasting. Measurements of diameter (DM), balloon pressure, and distensibility index (DI) of the pylorus were obtained twice over 5 min at 40, 50, and 60 ml balloon distensions.

KEY RESULTS

Pyloric DM at 40, 50, and 60 ml balloon distensions were 13.0 ± 2.5, 14.3 ± 1.8, and 17.2 ± 2.0 mm, respectively. DM with 60 ml distension was notably higher than with 40 and 50 ml distensions. Pyloric DI at 40, 50, and 60 ml distensions were 10.9 ± 4.8, 11.3 ± 5.8, and 11.1 ± 4.3 mm2 /mm Hg, respectively (p = 0.86). Linear regression and Bland-Altman plots showed similar distribution of the DM and DI during the second minute compared with the full 5-min measurements at 50 ml distension, as well as between two sequential measurements using 50 ml distension. With 50 ml balloon distension, intraindividual coefficients of variation (COVintra ) for DM and DI were 13.8% and 29.6%, respectively, and interindividual COV (COVinter ) were 12.6% and 51.3%, respectively. Similar reproducibility was obtained with 40 ml balloon distension.

CONCLUSIONS AND INFERENCES

Unsedated EndoFLIP® can be used to characterize human fasting pyloric diameter and distensibility, with best performance observed with 40 ml and 50 ml distensions and data collection during the second minute. Normative values reported serve as reference values for future studies.

Functional syndromes and symptom-orientated aftercare after esophagectomy

BACKGROUND

Surgery is the cornerstone of esophageal cancer treatment but remains burdened with significant postoperative changes of gastrointestinal function and quality of life.

PURPOSE

The aim of this narrative review is to assess and summarize the current knowledge on postoperative functional syndromes and quality of life after esophagectomy for cancer, and to provide orientation for the reader in the challenging field of functional aftercare.

CONCLUSIONS

Post-esophagectomy syndromes include various conditions such as dysphagia, reflux, delayed gastric emptying, dumping syndrome, weight loss, and chronic diarrhea. Clinical pictures and individual expressions are highly variable and may be extremely distressing for those affected. Therefore, in addition to a mostly well-coordinated oncological follow-up, we strongly emphasize the need for regular monitoring of physical well-being and gastrointestinal function. The prerequisite for an effective functional aftercare covering the whole spectrum of postoperative syndromes is a comprehensive knowledge of the pathophysiological background. As functional conditions often require a complex diagnostic workup and long-term therapy, close interdisciplinary cooperation with radiologists, gastroenterologists, oncologists, and specialized nutritional counseling is imperative for successful management.

Pyloric distensibility in health and disease

Until recently, gastric motility measurements in humans were mostly limited to accommodation (using barostat or 3-dimensional imaging studies of gastric volume) and gastric emptying tests, the latter being the only one performed in routine clinical care. Accurate and easy to use techniques were lacking to assess pyloric function in health and disease. Recently, pyloric distensibility has been developed and validated to assess pyloric opening. Several studies confirmed that pyloric distensibility was decreased in gastroparesis and correlated with gastric emptying as well as gastroparesis symptoms. In addition, pyloric distensibility may predict outcome of endoscopic techniques targeting the pylorus, namely intrapyloric botulinum toxin injection and gastric per-oral pyloromyotomy. Pyloric distensibility appears therefore to be a promising and useful new tool in the workup of gastroparesis patients.

Gastric peroral endoscopic myotomy for the treatment of refractory gastroparesis: a prospective single-center experience with mid-term follow-up (with video)

BACKGROUND AND AIMS

Gastroparesis (GP) is a multifactorial disease associated with a large burden on the health care systems. Pyloric-directed therapies including gastric peroral endoscopic myotomy (G-POEM) can be effective in improving patient quality of life and symptom severity. We report on the safety and efficacy of G-POEM and its impact on the quality of life of patients managed at a large referral center.

METHODS

Consecutive patients with confirmed GP referred for G-POEM due to failure of medical therapy were included. All patients were assessed at baseline and then at 1, 3, 6, and 12 and 24 months after G-POEM using validated symptom and quality of life instruments, including the Gastroparesis Cardinal Symptom Index (GCSI), Patient Assessment of Gastrointestinal Disorders Symptom Severity Index (PAGI-SYM), and 36-Item Short Form Survey (SF-36). Patients were evaluated before and 6 months after the procedure with EGD, 4-hour scintigraphy, and pyloric EndoFLIP. Technical success was defined as the ability to perform full-thickness pyloromyotomy. Clinical response was defined as an improvement of ≥1 point on GCSI.

RESULTS

Fifty-two patients (median age, 48 years; range, 25-80 years, 88% female) underwent G-POEM between February 2018 and September 2020 for the following phenotypes: vomiting-predominant (n=30), dyspepsia-predominant (n=16), and regurgitation-predominant (n=6) GP. The technical success rate was 100%. Adverse events were noted in 3 of 52 patients (5.77%), and were all managed successfully endoscopically. Clinical response was achieved in 68%, 58%, and 48% of patients at 1-month, 6-month, and 12-month follow-up (P < .001, P < .001, and P < .01, respectively). When classified by the cause of GP, the clinical response rates were diabetic GP 64% (11 of 17), postsurgical GP 67% (6 of 9), and idiopathic GP 72% (13 of 18). A statistically significant improvement in PAGI-SYM scores was observed at 1, 3, 6, 12, and 24 months, in addition to significant improvement in several domains of SF-36. Mean 4-hour gastric emptying was reduced 6 months after G-POEM (10.2%) compared with baseline (36.5%, P < .001). We report a significant reduction in the number of emergency department visits and days spent in the hospital up to 24 months after G-POEM.

CONCLUSIONS

G-POEM appears to be a safe and feasible treatment alternative for refractory GP with significant short-term and mid-term improvements in overall symptoms, quality of life scores, and health care utilization.