Short-term outcomes of gastric per-oral endoscopic pyloromyotomy (G-POEM) then and now: a comparison analysis
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Shazia Rashid, Michelle Neice, Maryam Mubashir, Syed Musa Raza, Natalie Roppolo, Victoria Andrus, David Okuampa, Brittany Pass, Elizabeth Armstrong, Ross Dies, Lena Kawji, Ashely Deville, Sidra Ahsan, Ass. Prof. Parit Mekaroonkamol, Prof. Qiang Cai, MD PhD
Gastric per-oral endoscopic pyloromyotomy (G-POEM) has been performed for 10 years in the treatment of refractory gastroparesis (Gp). Many studies from the early years of G‑POEM reported short-term outcomes with 60–80% clinical success. Notably, no recent studies have assessed short-term outcomes after a decade of experience with this procedure. In this study, we compare the short-term outcomes of our initial 16 patients undergoing G‑POEM 8 years ago with 16 of our recent patients undergoing G‑POEM.
Patients and methods
The initial 16 patients who underwent G‑POEM from 06/2015 to 07/2016 (group A; the first 16 G-POEM procedures QC performed) and 16 recent patients who underwent G‑POEM from 07/2021 to 01/2022 (group B; the first 16 procedures performed when QC moved to a different institution) were enrolled in the study. Patients’ demographics, clinical success, procedure time, and length of hospital stay were analyzed and compared between the two groups. All procedures were performed by a single advanced endoscopist (QC).
Results
Patients’ age, gender, and etiology of gastroparesis were similar between the two groups. There were no differences between the two groups in terms of short-term clinical outcomes. However, there was a significant difference in procedure time and the length of hospital stay between the two groups. There were no adverse events reported for either group A or group B.
Conclusion
For a single experienced advanced submucosal endoscopist, there were no differences in the short-term clinical outcomes of G‑POEM when comparing the initial timeframe of performing G‑POEM with that after 8 years of experience at the time of the study in a different institution. Notably, the procedure time and the length of hospital stay were significantly shorter after 8 years of practice.
Hinweise
An abstract was presented at the ACG annual meeting 2022, Charlotte, NC, USA.
The authors Shazia Rashid and Michelle Neice contributed equally to the manuscript.
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Introduction
Gastroparesis is a chronic debilitating motility disorder with few therapeutic options [1‐3]. Diabetes mellitus, vagal nerve injury during foregut surgery, gastrointestinal infection, and neurologic diseases such as multiple sclerosis are several known causes of gastroparesis. In addition, a significant proportion of patients have idiopathic gastroparesis without a clear underlying cause [1, 3]. Postprandial fullness, nausea, retching, vomiting, bloating, abdominal distension, and upper abdominal discomfort are the primary symptoms of patients with gastroparesis. These symptoms have detrimental effects on patients’ quality of life. Gastroparesis is usually managed by a stepwise algorithm beginning with dietary modifications, pharmacologic therapy including prokinetic/antiemetic medications, and endoscopic or surgical interventions. Endoscopic interventions in the past included dilation, intrapyloric botulinum injection, and transpyloric stenting. Surgical interventions include gastric electrical stimulation, laparoscopic pyloroplasty, and gastrostomy [1, 4].
Despite the variable treatment options, the management of gastroparesis remains challenging. Neurologic adverse effects limit the use of metoclopramide, one prokinetic medication for gastroparesis [5]. Many patients do not respond to the above endoscopic treatment and surgical interventions [6‐8]. Gastrostomy or gastrectomy for gastroparesis is too invasive and unsuitable for many patients.
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Gastric per-oral endoscopic pyloromyotomy (G-POEM) is emerging as a promising treatment option for refractory gastroparesis. It was first introduced in humans in 2013 [9]. Followed by encouraging results in several studies [6‐11], G‑POEM has become an appealing minimally invasive therapeutic modality for patients with refractory symptoms [6‐11]. We previously reported data on the short-term outcomes of our initial 16 patients [12]. We feel it will be interesting to update this data after nearly a decade of experience in a then-and-now comparison. Therefore, the purpose of this study is to systematically analyze and compare the short-term clinical outcomes of our initial 16 patients with the short-term clinical outcomes of 16 recent patients, namely the first in whom QC performed G‑POEM after he moved to a different institution, to determine the effects of G‑POEM roughly 8 years on.
Methods
Patients
This is a retrospective study evaluating the clinical benefits of G‑POEM in patients with medically refractory gastroparesis from the early timeframe of the G‑POEM procedure 8 years ago and from later on, when the endoscopist (QC) moved to Louisiana State University Health Sciences (LSUHS) Shreveport, LA, USA. The first 16 G-POEM patients in the two institutions were enrolled for the study. The study was approved by the institutional review boards at Emory University and at LSUHS Shreveport.
The short-term outcome analysis of our initial 16 patients was performed by QC at Emory University in Atlanta, Georgia; the results were published in 2017 [12]. The recent 16 patients were the first 16 patients in whom G‑POEM was performed by QC at LSUHS Shreveport.
The methods were published in our previous study [12]. Briefly, refractory gastroparesis was defined in patients with gastroparesis who did not respond to dietary modifications and prokinetic medications. Those patients were evaluated, offered G‑POEM, and enrolled in the study. The inclusion criteria were 1) patients with refractory gastroparesis, 2) patients with nausea and vomiting as the predominant symptoms, and 3) patients with at least one follow-up after G‑POEM. Exclusion criteria were 1) patients with an inability to tolerate general anesthesia, 2) patients with any contraindications to endoscopy, 3) patients with narcotic dependence, and 4) patients with abdominal pain as the predominant symptom because of concern of overlapping functional pain.
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Beginning June 2015, all consecutive first patients (16) who underwent G‑POEM before July 2016 at Emory University were included as the initial patient population in group A. From July 2021 to January 2022, another first 16 consecutive patients at LSUHS were enrolled as group B.
All patients had gastroparesis confirmed by a 4-hour gastric emptying scan (GES) and underwent standard upper gastrointestinal (GI) endoscopy to exclude gastric outlet obstruction. The data collected included patient demographics, cause and duration of gastroparesis, previous failed treatments, Gastroparesis Cardinal Symptoms Index (GCSI), endoscopic data, total duration of procedure, intra- and postoperative adverse events, and length of hospital stay.
Gastroparesis Cardinal Symptoms Index
The Gastroparesis Cardinal Symptoms Index (GCSI) is based on three categories and nine subsets: postprandial fullness/early satiety (four subsets), nausea/vomiting (three subsets), and bloating (two subsets) [13]. The score for each index ranged from 0 to 5. A total score (range 0–45) was obtained for each patient and reported as a mean GCSI in this study.
The primary outcome of the study was the clinical success rate in the two patient groups. Clinical success as reported in our previous study was defined as an improvement in symptoms as measured by a decrease in mean GCSI with a 25% or greater decrease in at least two subsets of cardinal symptoms [12]. Secondary outcomes were procedural time, which was defined by the duration of scope in and scope out; the duration of hospital stay; and adverse events.
G-POEM procedure
In both patient groups, the procedure was performed by QC and assisted by a trainee. All of the procedures were performed with the patient under general anesthesia in the endoscopy suite, with the patient in supine position. All procedures were successful. Patients were kept on a clear liquid diet for 2 days before G‑POEM and were nil per os (NPO) from midnight prior to the day of planned G‑POEM. Patients were administered 4.5 g of piperacillin/tazobactam intravenously or 500 mg of levofloxacin intravenously (if allergic to penicillin) shortly before or during the procedure. Patients remained NPO during hospitalization for the night after the procedure. Oral antibiotics were prescribed upon discharge for a total of 5 days. A gastroscope (GIF-H190; Olympus, Tokyo, Japan) with a transparent distal cap attachment (MH 588; Olympus) was used for all procedures.
The esophagus and the stomach were cleared of any retained particulate matter with water lavage and suction. A hook knife (Olympus) or an I‑type Hybrid knife (ERBE, Tübingen, Germany) was used to perform the mucosal incision. Carbon dioxide was used for insufflation (UCR; Olympus) in all cases throughout the procedure. A Coagrasper (FD-411QR; Olympus) was used to achieve hemostasis in the submucosal plane in the soft coagulation mode (ERBE) when needed.
After a routine upper GI endoscopic examination, a mucosal entry site was identified consistently at the 5 o’clock position, approximately 5 cm proximal to the pylorus along the greater curvature of the stomach. The steps of G‑POEM are described in our previous report [12]. Briefly, a submucosal bleb was created with a premixed methylene blue/normal saline (5 mL/500 mL) solution using a sclerotherapy needle (only a few cases) or a hybrid knife for injection (Olympus) in group A. In group B, a hook knife or a hybrid knife was used. A 2‑cm mucosal incision was made with the same knife. A submucosal tunnel was created by dissection of submucosal fibers using the spray coagulation mode 50 W on effect 2 (ERBE) from the mucosal entry site to the pyloric ring. Careful attention was given to avoiding any injury to the mucosal layer. After the pyloric ring had been identified, a 1- to 3‑cm myotomy was performed. The mucosal entry site was closed with three to five hemostatic clips (Fig. 1).
Fig. 1
Gastric per-oral endoscopic pyloromyotomy (G-POEM) procedure steps: a gastric antrum; b a submucosal bleb was created with a premixed methylene blue/normal saline (5 mL/500 mL) solution using a sclerotherapy needle (only a few cases) or a hybrid knife; c a 2-cm mucosal incision was made with the same knife. A submucosal tunnel was created by dissection of submucosal fibers using the spray coagulation mode 50 W on effect 2 (ERBE, Tübingen, Germany) from the mucosal entry site to the pyloric ring; d careful attention was given to avoiding any injury to the mucosal layer; e myotomy on the pyloric ring; f mucosal entry site was closed with three to five hemostatic clips
×
Evaluation after G-POEM
For group A, all patients were admitted to the hospital and evaluated with an upper GI contrast study on postoperative day 1. If the study results were normal, they were started on a clear liquid diet. For group B patients, routine upper GI contrast study was no longer performed. Patients were started on a clear liquid diet on postoperative day 1 as long as no adverse events or other concerns were present. For both groups, patients were typically observed in the hospital overnight and discharged after tolerating a clear liquid diet. Patients were continued on proton pump inhibitor therapy for 8 weeks, and this medication was continued, if needed, during clinical follow-up. They maintained a clear liquid diet for 1 week and were then allowed five to six small meals of a low-fiber, low-fat diet per day. Patients were followed up within 1 to 2 months after G‑POEM and then as needed.
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Statistical analysis
Data were retrospectively collected and comparison of the parameters before and after the procedure was performed. Data are presented as frequencies and percentages and means with standard deviation. Normally distributed data were analyzed using a paired t‑test. Comparison of data from groups A and B was also performed using a paired t‑test. A p-value of less than 0.05 was considered statistically significant. Data were analyzed using IBM SPSS version 22.0 statistical software (IBM Corporation, Armonk, NY, USA).
Results
Patients’ demographic information and G-POEM procedures
The results of our initial 16 patients in group A were reported 8 years ago [12]. Those consecutive patients were enrolled between June 2015 and July 2016. To parallel group A, we enrolled another 16 consecutive patients (the first 16 patients at LSUHS) from July 2021 to January 2022. Patients’ general information, causes of gastroparesis, and history of previous treatments are presented in Table 1. The mean disease duration before G‑POEM was 4.9 and 3.9 years in group A and group B, respectively. The mean age in group A and group B was 44.8 ± 14.8 and 47.8 ± 18.8 years, respectively. Group A had 13 female patients and group B had 12. The numbers of diabetic, idiopathic, and postsurgical cases of gastroparesis were 8, 4, and 4 for group A and 9, 5, and 2 for group B, respectively. All patients had failed medical treatment. Four patients in group A and one patient in group B had a gastric electrical stimulator (Table 1).
Table 1
Study population
Group A
Group B
Age (years)
44.8 ± 14.8
47.8 ± 18.8
Male gender, n (%)
3 (19)
4 (25)
Race, n (%)
White
12 (75)
10 (63)
African American
4 (25)
6 (37)
Asian
0 (0)
0 (0)
Unknown
0 (0)
0 (0)
Cause of gastroparesis, n (%)
Diabetes
9 (56)
8 (50)
Postsurgical
1 (6)
4 (25)
Postinfection
1 (6)
0 (0)
Idiopathic
5 (31)
4 (25)
BMI (kg/m2), mean±SD
24.7 ± 6.1
29.4 ± 9.0
Failed therapy before G‑POEM
Failed medication
16 (100)
16 (100)
Failed gastric stimulator
4 (25)
1 (6)
Nutritional status before G‑POEM
Oral diet but only liquid can be tolerated
12 (75)
16 (100)
Enteral feeding via PEG‑J
3 (19)
0 (0)
TPN dependence
1 (6)
0 (0)
GCSI (pre-G-POEM), mean ± SD
3.40 ± 0.5
3.35 ± 0.7
Patients with frequent hospitalizations, n (%)
12 (75)
16 (100)
Group A: patients who underwent G‑POEM procedures from 06/2015 to 07/2016 identified as the initial set of the patient population. Group B: patients who underwent G‑POEM from 07/2021 to 01/2022 identified as the recent set of the patient population
BMI Body mass index, SD standard deviation, G-POEM gastric peroral endoscopic pyloromyotomy, PEG-J percutaneous endoscopic gastrostomy-jujunal tube, GCSI gastroparesis cardinal symptom index
GCSI before and short-term follow-up after G‑POEM
G‑POEM was successfully performed in all 32 patients (100%). In group A, 13 of 16 (81%) patients had a significant improvement in the mean GCSI after G‑POEM: 3.40 ± 0.50 before the procedure (16 patients) to 1.48 ± 0.95 (P < 0.0001) at 1 month (16 patients). In group B, 13 out of 16 (81%) patients had a significant improvement in the mean GCSI after G‑POEM: 3.35 ± 0.70 before the procedure (16 patients) to 1.51 ± 0.82 (P < 0.001) at 56 ± 22.6 days (15 patients; 1 patient had no follow-up). There was no significant difference between the two groups in terms of patients’ general information and short-term clinical outcomes (Tables 1 and 2).
Table 2
Primary outcomes of G‑POEM 7 years ago and 7 years later
Group A
Group B
GCSI, mean ± SD
3.40 ± 0.5
3.35 ± 0.7
Before G‑POEM
3 (19)
4 (25)
I to 2 months after G‑POEM
1.48 ± 0.95
1.51 ± 0.85
Success rate at 1 to 2 months
81%
81%
Group A: patients who underwent G‑POEM procedures from 06/2015 to 07/2016 identified as the initial set of the patient population. Group B: patients who underwent G‑POEM from 07/2021 to 01/2022 identified as the recent set of the patient population
SD Standard deviation, G-POEM gastric peroral endoscopic pyloromyotomy, GCSI gastroparesis cardinal symptom index
Procedure time, length of hospital stay, and other parameters
There was a significant difference in procedure time and the length of hospital stay between the two groups: the procedure times were 49.7 ± 22.1 min for group A and 29.6 ± 10.1 min for group B (p < 0.001). The length of hospital stay was 2.47 ± 0.7 and 1.18 ± 0.4 days (P < 0.01) for groups A and B, respectively (Table 3). There were no adverse events in either group (Table 3).
Table 3
Secondary outcomes of G‑POEM
Primary outcome
Group A
Group B
p-value
Clinical success ratea, n (%)
13/16 (81%)
13/16 (81%)
–
Procedure time (min ± SD)
49.7 ± 22.1
29.6 ± 10.1
P < 0.001
Length of hospital (days)
2.47 ± 0.7
1.18 ± 0.4
P < 0.001
Adverse events, n (%)
0 (0)
0 (0)
–
Recurrent hospitalization for gastroparesis-related symptoms, n (%)
3/16 (19%)
2/16 (13%)
–
Group A: patients who underwent G‑POEM procedures from 06/2015 to 07/2016 identified as the initial set of the patient population. Group B: patients who underwent G‑POEM from 07/2021 to 01/2022 identified as the recent set of the patient population
aClinical success was defined as an improvement in symptoms as measured by a decrease in mean GCSI and a significant decrease in at least two subsets of cardinal symptoms and no hospitalization for gastroparesis-related symptoms
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In group A, 3 patients for whom G‑POEM failed were hospitalized for recurrent gastroparesis-related symptoms; all 3 had diabetic gastroparesis and 2 had the procedure done as an inpatient. In group B, two patients for whom G‑POEM failed were hospitalized for similar symptoms; both had diabetic gastroparesis and one patient required referral for a gastric pacemaker.
Discussion
The first paper on G‑POEM was published in 2013 [11]. G‑POEM is a relatively new and moderately effective therapeutic modality for refractory gastroparesis. Gastroparesis is often difficult to treat because its pathogenesis is complex and incompletely understood. We published the first paper on the short-term outcomes of G‑POEM in our initial set of 16 patients about 8 years ago [12]. Since that time, several studies on short-term outcomes have been published with different rates of clinical efficacy ranging from 60 to 80% [6‐11, 15‐22]. The experience of a surgeon is one of the most important factors related to the outcome of a surgical procedure [14]. It is interesting to compare the short-term outcomes of G‑POEM performed by the same submucosal endoscopist early in his experience with a procedure and after years of practice with the same procedure in a different institution. To our knowledge, this is the first report of such a study.
The overall clinical success rate of 81%, with varying degrees of improvement in each domain of the cardinal symptoms, is similar between groups A and B, despite 8 additional years of endoscopy experience between groups A and B. The 80% clinical success rate in short-term follow-up is consistent with studies reported earlier in the literature [12, 15‐22]. Interestingly, this finding indicates that there is a separate factor determining efficacy that has not changed over this 8‑year period.
First, the efficacy of G‑POEM may largely be determined by the selection of patients. Selection criteria have not significantly changed or improved since the outset of G‑POEM. Two prior studies identified obesity, a long duration of gastroparesis, and frequent use of psychic and pain medications as being associated with unsuccessful G‑POEM outcomes [9, 24]. However, standardized cut off values for body mass index (BMI), duration of disease, or medication exposure have not been established; therefore, such factors have not been used for patient selection before the G‑POEM procedure. In another previous study, our group analyzed proximal and distal gastric retention in gastric emptying scintigraphy and tried to identify the best candidates for G‑POEM; this preliminary study suggested that the proximal-to-total T½ ratio may represent an important patient selection factor for G‑POEM [23]. However, we need to study a larger sample size to validate it.
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Unlike esophageal achalasia, where a tight esophagogastric junction predicts a good outcome after peroral endoscopic myotomy (POEM) [25, 26], a tight gastric outlet may not predict a good outcome after G‑POEM. One recent study concluded that endoscopic findings, such as the degree of pylorospasm and the amount of bile or food in the stomach, do not predict G‑POEM outcomes [27]. Therefore, at this time, there are no methods that reliably predict the outcome of G‑POEM before the procedure [27]. It is possible that once we have a way to identify and select those patients most likely to benefit from G‑POEM, the clinical success rate will increase further, and we will spare patients who are unlikely to respond. However, at this time, we cannot reliably predict the outcome of the procedure in advance.
Secondly, another reason for non-responsiveness to G‑POEM is possibly inadequate myotomy. Some studies used an intraoperative functional luminal imaging probe during G‑POEM to measure the distensibility or the cross-sectional area or diameter of the pyloric ring and tried to establish a criterium to predict the outcome of G‑POEM during the procedure [28‐30]. However, all these studies are preliminary at this time and no firm conclusions have been made.
Thirdly, the single endoscopist in this study, QC, had performed more than 100 esophageal POEM procedures, a procedure similar to G‑POEM, before his first 16 G-POEM procedures at Emory University. Therefore, we cannot conclude at this time that the experience of an endoscopist has no effect on the outcome of G‑POEM for a less experienced submucosal endoscopist.
Although the clinical success rate did not change, the procedure time and length of hospital stay were significantly shorter in group B when compared to the earlier patients in group A. Procedure time dropped from an average of 49 min to 29 min. The group B patients underwent the procedure in an endoscopic center which had little to no experience in submucosal endoscopy prior to the study. Therefore, the procedure time for the group B patients might have been even shorter if the staff had been experienced. Furthermore, the length of hospitalization went down from an average of 2.5 days to 1.2 days. After our study on the first 16 patients in group A [12], we performed a study on same-day discharge after G‑POEM which showed that about 50% of patients could be discharged the same day after G‑POEM. However, to retain the comparison with group A, we kept all patients in group B for overnight observation and did not discharge any patients on the day of the procedure.
We acknowledge there are some limitations to this study: it is a single-center retrospective study with a small number of patients, the procedures were performed by the same endoscopist but not at the same institution, and the endoscopist already had POEM experience before performing G‑POEM on his initial 16 patients. Nevertheless, these data add important information to the literature by presenting short-term outcomes of G‑POEM in its early days and after multiple years of experience. It is an interesting finding that the efficiency has significantly improved in the past 8 years, with shorter procedure times and hospital stays, despite the clinical efficacy remaining stagnant at 80%. We feel that this finding emphasizes the fact that to further increase the clinical efficacy of G‑POEM, at least for an experienced endoscopist, more research is needed to optimize pre-procedure patient selection.
Conflict of interest
S. Rashid, M. Neice, M. Mubashir, S.M. Raza, N. Roppolo, V. Andrus, D. Okuampa, B. Pass, E. Armstrong, R. Dies, L. Kawji, A. Deville, S. Ahsan, P. Mekaroonkamol, and Q. Cai declare that they have no competing interests.
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Short-term outcomes of gastric per-oral endoscopic pyloromyotomy (G-POEM) then and now: a comparison analysis
verfasst von
Shazia Rashid Michelle Neice Maryam Mubashir Syed Musa Raza Natalie Roppolo Victoria Andrus David Okuampa Brittany Pass Elizabeth Armstrong Ross Dies Lena Kawji Ashely Deville Sidra Ahsan Ass. Prof. Parit Mekaroonkamol Prof. Qiang Cai, MD PhD
