BARIATRIC SERIES Emerging technology: endoluminal treatment of obesity Gregory A. Cote ´, MD, MS, Steven A. Edmundowicz, MD, FASGE St. Louis, Missouri, USA Background: Bariatric surgery remains the most effective treatment for the management of obesity. Endolumi- nal interventions offer the potential for an ambulatory weight loss procedure that may be safer and more cost-effective compared with current laparoscopic approaches. Objective: We review the currently available endoluminal techniques for obesity that have been presented or discussed in public forums and meetings, focusing on those with published trials. Design: Literature review. Results: Human trials of endoluminal treatments of obesity are primarily limited to restrictive interventions, including intragastric balloons, transoral gastroplasty, and endoluminal vertical gastroplasty. Currently, the duo- denojejunal bypass sleeve is the only endoluminal device that has been studied in humans that promotes weight loss through malabsorption. Early results of these technologies are promising, but long-term data are lacking. Conclusions: Endoluminal treatments for obesity have promise, and recent technological advances have been astounding. However, these interventions will need to be held to the same standards of current operative tech- niques. Each device will need to be scrutinized within clinical trials to determine its safety, efficacy, and durability. (Gastrointest Endosc 2009;70:991-9.) In a continuation of this series on endoscopic topics related to obesity, we are pleased to review the current status of endoluminal treatment of obesity. Bariatric sur- gery remains the most effective intervention for persons with a body mass index (BMI) of 40 or greater or those with a BMI of 35 or greater with underlying comorbidities such as diabetes, sleep apnea, and hypertension. 1-3 Lapa- roscopic techniques such as Roux-en-Y gastric bypass and gastric banding are increasingly preferred, with esti- mated mortality rates of 1% to 2%. 4 Cardiopulmonary events and anastomotic leaks are the most commonly cited sources of morbidity and mortality. Other important causes are attributable to technical complications such as postoperative infections and strictures. Despite the low rate of complications related to laparoscopic bariatrics, there is a growing interest in endoluminal and transgastric devices for preoperative or stand-alone weight loss procedures. 5,6 Endoluminal sur- gery, performed entirely through the GI tract by using flexible endoscopy, offers the potential for an ambulatory weight loss procedure that may be safer and more cost- effective compared with current laparoscopic approaches. If such an approach is developed, endoluminal therapy may extend the current indications for intervention to those with multiple comorbidities, older age, and those with mild obesity (BMI 30-35). The human data on endoluminal surgery as a primary modality for weight loss are limited. Current approaches vary from the use of intragastric balloons to endoluminal suturing or stapling as a means to modify gastric volume. These are comparable to the purely restrictive interven- tions such as the gastric banding or vertical banded gas- troplasty. More nascent technology involves electrical stimulation to delay gastric emptying 7-9 or deploying a duodenojejunal sleeve as an intestinal bypass/malab- sorptive intervention. Other interesting approaches are on the horizon. We review the currently available endo- luminal techniques for obesity that have been presented Abbreviations: BIB, BioEnterics Intragastric Balloon; BMI, body mass index; DJBS, duodenojejunal bypass sleeve; EndoCinch, endoluminal vertical gastroplasty; %EWL, percentage of excess weight loss; GEJ, gastroesophageal junction; TOGA, transoral gastroplasty. DISCLOSURE: The following author disclosed financial relationships relevant to this publication: S. A. Edmundowicz: Stock options from Satiety; research support from Davol; consultant to and research support from Boston Scientific. The other author disclosed no financial relationship relevant to this publication. Copyright ª 2009 by the American Society for Gastrointestinal Endoscopy 0016-5107/$36.00 doi:10.1016/j.gie.2009.09.016 www.giejournal.org Volume 70, No. 5 : 2009 GASTROINTESTINAL ENDOSCOPY 991
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BARIATRIC SERIES
Emerging technology: endoluminal treatment of obesityGregory A. Cote, MD, MS, Steven A. Edmundowicz, MD, FASGE
St. Louis, Missouri, USA
Background: Bariatric surgery remains the most effective treatment for the management of obesity. Endolumi-nal interventions offer the potential for an ambulatory weight loss procedure that may be safer and morecost-effective compared with current laparoscopic approaches.
Objective: We review the currently available endoluminal techniques for obesity that have been presented ordiscussed in public forums and meetings, focusing on those with published trials.
Design: Literature review.
Results: Human trials of endoluminal treatments of obesity are primarily limited to restrictive interventions,including intragastric balloons, transoral gastroplasty, and endoluminal vertical gastroplasty. Currently, the duo-denojejunal bypass sleeve is the only endoluminal device that has been studied in humans that promotes weightloss through malabsorption. Early results of these technologies are promising, but long-term data are lacking.
Conclusions: Endoluminal treatments for obesity have promise, and recent technological advances have beenastounding. However, these interventions will need to be held to the same standards of current operative tech-niques. Each device will need to be scrutinized within clinical trials to determine its safety, efficacy, and durability.(Gastrointest Endosc 2009;70:991-9.)
In a continuation of this series on endoscopic topicsrelated to obesity, we are pleased to review the currentstatus of endoluminal treatment of obesity. Bariatric sur-gery remains the most effective intervention for personswith a body mass index (BMI) of 40 or greater or thosewith a BMI of 35 or greater with underlying comorbiditiessuch as diabetes, sleep apnea, and hypertension.1-3 Lapa-roscopic techniques such as Roux-en-Y gastric bypassand gastric banding are increasingly preferred, with esti-mated mortality rates of 1% to 2%.4 Cardiopulmonaryevents and anastomotic leaks are the most commonlycited sources of morbidity and mortality. Other important
Abbreviations: BIB, BioEnterics Intragastric Balloon; BMI, body mass
vertical gastroplasty; %EWL, percentage of excess weight loss; GEJ,
gastroesophageal junction; TOGA, transoral gastroplasty.
DISCLOSURE: The following author disclosed financial relationships
relevant to this publication: S. A. Edmundowicz: Stock options from
Satiety; research support from Davol; consultant to and research
support from Boston Scientific. The other author disclosed no
financial relationship relevant to this publication.
Copyright ª 2009 by the American Society for Gastrointestinal Endoscopy
0016-5107/$36.00
doi:10.1016/j.gie.2009.09.016
www.giejournal.org
causes are attributable to technical complications such aspostoperative infections and strictures.
Despite the low rate of complications related tolaparoscopic bariatrics, there is a growing interest inendoluminal and transgastric devices for preoperative orstand-alone weight loss procedures.5,6 Endoluminal sur-gery, performed entirely through the GI tract by usingflexible endoscopy, offers the potential for an ambulatoryweight loss procedure that may be safer and more cost-effective compared with current laparoscopic approaches.If such an approach is developed, endoluminal therapymay extend the current indications for intervention tothose with multiple comorbidities, older age, and thosewith mild obesity (BMI 30-35).
The human data on endoluminal surgery as a primarymodality for weight loss are limited. Current approachesvary from the use of intragastric balloons to endoluminalsuturing or stapling as a means to modify gastric volume.These are comparable to the purely restrictive interven-tions such as the gastric banding or vertical banded gas-troplasty. More nascent technology involves electricalstimulation to delay gastric emptying7-9 or deployinga duodenojejunal sleeve as an intestinal bypass/malab-sorptive intervention. Other interesting approaches areon the horizon. We review the currently available endo-luminal techniques for obesity that have been presented
Emerging technology: endoluminal treatment of obesity Cote & Edmundowicz
or discussed in public forums and meetings, focusing onthose with published trials. Because this field is rapidlyevolving, many of the concepts and devices are earlyin their development and have yet to be evaluated in hu-man trials.
Human studies of devices for weight loss are difficult todesign and complete. When assessing response to weightloss devices, there are numerous confounding variables in-cluding a strong placebo effect, variable patient compli-ance with dietary instructions and exercise programs,and limitations on randomization other than by BMI andfailure of standard medical weight loss programs beforeenrollment. The ideal device trial design would be a ran-domized, controlled, double-blind evaluation of the de-vice in an identical environment of dietary control,exercise, and patient education. Few devices have beenevaluated in this manner.
Comparison of the efficacy of endoluminal therapiesfor weight loss can also be difficult. Although a numberof endpoints can be used, most studies calculate the per-centage of excess weight loss (%EWL) as a measure of ef-ficacy. For an individual patient, excess weight is calculatedas the difference between the patient’s weight and the re-ported weight of an average body mass individual witha BMI of 25. Some studies calculate the loss of excessBMI by comparing the patient’s weight with that of a pa-tient with the same height at a BMI of 25. This interval dif-ference of the excess weight and the percentage of thatweight lost after a device intervention is the %EWL orthe percentage of excess BMI weight loss.
Weight loss after an intervention is not static, and manyindividuals plateau and regain weight in the months toyears after the intervention. To have a meaningful effecton a patient’s health, the weight loss needs to be lasting.Ideally, an endoluminal therapy would lead to modifica-tions of a patient’s eating habits to promote weight lossfollowed by long-term maintenance. Endoluminal thera-pies that are easy to apply and of low risk could be re-peated at variable intervals to promote more long-lastingweight loss.
INTRAGASTRIC BALLOON
One of the earliest concepts for the endoluminal treat-ment of obesity involved deploying intragastric balloons torestrict oral intake.10-15 Initial experiences failed to achievemeaningful weight loss or were met with significant com-plications. A number of intragastric balloons have been inuse worldwide, and several have been withdrawn from themarket. With a spherical shape and larger capacity thanearlier models, the BioEnterics Intragastric Balloon (BIB)(Allergan, Irvine, Calif) is the intragastric balloon thathas been most extensively studied. The BIB is deployedin the stomach under direct vision and inflated with 500to 700 mL of saline/methylene blue solution (Fig. 1).
The device can be deflated by using a variety of needlesand removed with a snare or basket. As many as two thirdsof patients may report nausea and vomiting that in somecases can require early removal. Other commonly citedcomplications include early deflation and gastric ulcera-tions and erosions.
In a retrospective analysis of 2515 patients witha mean BMI of 44.8 � 7.8 kg/m2 who underwent endo-scopic placement of the BIB, only 2 (0.08%) were unsuc-cessful.16 At 6-month follow-up, the %EWL was 33.9 �18.7. During this interval, improvement or resolution
Figure 1. Intragastric balloon. A, The BioEnterics Intragastric Balloon.
The balloon is smooth and spherical. The arrows at the equator point
toward the valve. The shell consists of inert, nontoxic silicone elastomer,
impervious and resistant to gastric acid. The radiopaque self-sealing and
repenetrable valve with its Z-shape configuration (visible inside balloon)
allows adjustment of the balloon volume from 400 to 800 mL. B, Plain
abdominal radiograph showing balloon in body of stomach. A coin taped
on the lower sternum permits follow-up comparisons of balloon size to
detect premature deflation. Reprinted with permission from Mathus-Vlie-
gen EM, Tytgat GN. Intragastric balloon for treatment-resistant obesity:
safety, tolerance, and efficacy of 1-year balloon treatment followed by
a 1-year balloon-free follow-up. Reprinted with permission from the
American Society of Gastrointestinal Endoscopy. Mathus-Vliegen EMH,
Tytgat GNJ. Intragastric balloon for treatment-resistant obesity: safety, tol-
erance, and efficacy of 1-year balloon treatment followed by a 1-year bal-
Cote & Edmundowicz Emerging technology: endoluminal treatment of obesity
Figure 2. Endoluminal suturing using endoluminal vertical gastroplasty (EndoCinch).22 A, Aspirate tissue just below the Z-line. B, Needle with pre-
loaded suture advanced. C, Cinching/deployment device advanced. D, Final appearance of placation in cardia. Reprinted with permission from Roth-
stein RI, Filipi CJ. Endoscopic suturing for gastroesophageal reflux disease: clinical outcome with the Bard EndoCinch. Gastrointest Endosc Clin N Am
2003;13:89-101.
of diabetes and hypertension was observed in 86.9% and93.7%, respectively. The authors reported a complicationrate of 2.8%, including 5 (0.19%) patients in whom a gas-tric perforation developed, 2 of whom consequentlydied. Similar results were duplicated in a series of 26high-risk, superobese patients with a mean BMI of 65.3� 9.8 and at least 3 medical comorbidities such as diabe-tes, hypertension, and sleep apnea.17 These patientswere specifically identified as at unacceptable risk to un-dergo bariatric surgery as a primary intervention, soa BIB was inserted in anticipation of undergoing a weightloss surgery during a second stage. At 6-month follow-upin most patients, the %EWL was 22.4 � 14.5 and im-provement/resolution of diabetes and hypertensionwas 81% and 83%, respectively. One patient died within24 hours of BIB placement as a result of severe aspira-tion. The efficacy of the intragastric balloon was furthersupported in a randomized, sham-controlled, crossoverstudy of 32 patients.18
Newer designs have been proposed, allowing place-ment under direct visualization into the gastric fundusby pulling the balloon alongside the gastroscope by usinga polypectomy snare.19 However, the durability of intra-gastric balloon therapy is limited because the device istypically removed after 6 months, returning the patientto his or her baseline anatomy. Still, these have beenused successfully as a precursor to more definitive bariat-
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ric intervention in thousands of patients. There iscurrently no intragastric balloon approved for use inthe United States. Although there is a greater body ofevidence supporting the short-term efficacy and safetyof intragastric balloons, more provocative and potentiallydurable mechanisms are becoming available.
Has been described using the Bard EndoCinch SuturingSystem (C.R. Bard, Murray Hill, NJ). The EndoCinch wasinitially devised for the endoscopic treatment of GERD.Its acceptance as a therapy for GERD has gained little trac-tion because of its lack of durability and often incompletecontrol of reflux symptoms.20-22 The suturing device iscontained within a capsule that is attached to the end ofa diagnostic gastroscope. The initial procedure was per-formed by using an overtube and required the use of 2gastroscopes: one to sew, using the attached capsulewith suture with a T tag at the terminal end that is broughtthrough the tissue and out of the mouth, and one to lockthe sutures in place using a suture anchor. To use this de-vice, tissue is suctioned into the capsule and a hollow nee-dle, preloaded with a T tag suture, is advanced throughthe captured tissue. In its original description for the treat-ment of GERD, a second T tag is deployed before cinchingthe 2 sutures together to lock the stitch in place (Fig. 2).
Emerging technology: endoluminal treatment of obesity Cote & Edmundowicz
Figure 3. Endoscopic suturing for vertical gastroplasty. Reprinted with permission from the American Society of Gastrointestinal Endoscopy. Fogel R,
De Fogel J, Bonilla Y, et al. Clinical experience of transoral suturing for an endoluminal vertical gastroplasty: 1-year follow-up in 64 patients. Gastrointest
Endosc 2008;68:51-8.
This procedure was repeated at the gastroesophagealjunction (GEJ) to create a plication and theoreticallyreduce the amount of refluxate.
Fogel et al23 first described the use of the EndoCinch forthe treatment of obesity in 64 patients. Seven sutures are de-ployed in a continuous and cross-linked fashion from theproximal fundus to the distal body (Fig. 3). Once the sutureis fixed, distention of the stomach is significantly limited.The authors reported a mean procedure time of 45 minutesand a recovery time of 1 to 2 hours, with all patients dis-charged on the day of procedure. Of 64 patients, 59 were fol-lowed for 12 months post-procedure. The %EWL improvedfrom 21.1% at 1 month to 58.1% at 12 months (Fig. 4). Only14 patients underwent repeat endoscopy between 3 and 12months of follow-up to assess the suture line; of these, 11remained completely or partially intact and did not requireadditional intervention. There were minimal complicationsreported. Recent attempts to duplicate the results obtained
in this trial have been reported in abstract form. Thompsonet al reported similar short-term efficacy with a newer ver-sion of the endoluminal vertical gastroplasty device in a 2-center U.S. trial of 16 patients.24 A randomized, multicentertrial is being initiated by Davol in the United States at thistime.
The durability of the GEJ plication has been called intoquestion in earlier trials of the EndoCinch for the treat-ment of GERD.20,21,25 Similar problems may arise becausethis device is used to restrict gastric distensibility. Sham-controlled trials are needed to further evaluate the utilityof this device in obesity. Well-designed studies with long-term follow-up will be needed to measure the durabilityof the observed weight loss. Particularly, the stability ofthe gastric sutures remains unproven given the lack oflong-term data. Finally, the ease of repeated interventionsto facilitate additional weight loss in refractory or recur-rent cases needs to be studied.
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Cote & Edmundowicz Emerging technology: endoluminal treatment of obesity
Inc, Palo Alto, Calif) uses the first endoscopic stapling de-vice to create a full-thickness plication in the proximalstomach.26,27 Using a strictly endoluminal approach,TOGA creates a gastric sleeve along the lesser curvatureof the stomach (Fig. 5). First, the TOGA Sleeve Stapler isintroduced over a guidewire into the proximal stomach.A gastroscope is advanced through the device andretroflexed to directly visualize the stapler. The greatercurvature is retracted by using an extendable wire to opti-mally align the stapler for plication. Then, using vacuumpods with suction, the stapler attaches to the anteriorand posterior walls of the stomach. The stapler is closedand fired, allowing a serosa-to-serosa apposition in parallelwith the lesser curvature of the stomach creating a gastricsleeve in this location. The stapler is withdrawn and re-loaded. A second firing of the stapler allows the sleeveto be extended to a total length of 8 cm from the GEJ.The sleeve’s luminal diameter of approximately 20 mm isreduced to approximately 12 mm by pleating the gastricsleeve by using the TOGA restrictor, which clamps andstaples gastric folds together after acquiring tissue viasuction. This process can be repeated as needed to createadditional plications and further narrowing the lumen ofthe sleeve.
The initial feasibility of this technique in 33 humansubjects was reported by Moreno et al26 and Devi�ere etal27 in 33 patients. All subjects underwent transoral gastro-plasty with no significant complications. The mean BMIwas more than 40 in both studies, and 1 or more comor-bidities was present in as many as 40% at the onset. Usingthe earliest generation of the Sleeve Stapler,27 only 8 of 21patients had a fully intact sleeve at discharge, and this per-
Figure 4. Percentage of excess weight (%EWL) loss, segmented into sub-
populations by body mass index (BMI) age (n Z 64). Post-op, postopera-
tively. Reprinted with permission from the American Society of
Gastrointestinal Endoscopy. Fogel R, De Fogel J, Bonilla Y, et al. Clinical
experience of transoral suturing for an endoluminal vertical gastroplasty:
1-year follow-up in 64 patients. Gastrointest Endosc 2008;68:51-8.
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sisted at 6-month follow-up in only 5 of 21. Despite this,the %EWL was 24.4 after 6 months and procedure-relatedadverse events were limited to the first week of follow-up,including nausea, vomiting, and pain. With a second-gen-eration stapler,26 an intact staple line was noted in 9 of11 patients at discharge and persisted in 7 of 11 after 6months of follow-up. Comparable to the initial experience,the mean %EWL of 19.2% at 1 month and 46.0% at 6months was significant.
TOGA is the first endoscopic device that offers trans-mural tissue apposition, which may promote a moredurable sleeve than other instruments such as the Endo-Cinch.23,28 With average procedure times of approximately2 hours, the technique seems feasible and is likely to be anambulatory procedure as operators become more com-fortable with the intervention. As with other restrictiveprocedures, the most challenging question for thisapproach will be the durability and extent of weightloss. A randomized, sham-controlled trial is ongoing inthe United States to further investigate this technique.
Duodenojejunal bypass sleeveThe first strictly endoluminal device used to bypass the
proximal small intestine is the duodenojejunal bypasssleeve (DJBS) (GI Dynamics, Inc, Watertown, Mass). Thedevice is composed of a self-expanding implant that seatsin the duodenum and is attached to a 60-cm plastic sleevethat extends into the proximal jejunum (Fig. 6). The de-vice is preloaded onto a wire-guided catheter systemthat is advanced into the small bowel under fluoroscopy.As described by Rodriguez-Grunert et al,29 the sleeve is de-ployed by pushing the inner sheath of the catheter intothe proximal jejunum. Once the sleeve is fully extended,a self-expanding anchor is released in the duodenal bulbto hold the device in place.
In the first reported human series, the DJBS was suc-cessfully deployed in all 12 patients with a mean implanta-tion time of 26.6 minutes.29 With the exception of 2patients in whom refractory abdominal pain developed re-quiring early extraction, the device remained in place for12 weeks and was successfully removed in a mean timeof 43.3 minutes. Two complications, an oropharyngealtear and an esophageal mucosal tear, were reported in 2subjects at the time of device withdrawal. These did notrequire surgical intervention and were considered minor.The mean %EWL after 12 weeks was 23.6.
A second human series was recently reported fromChile evaluating sleeve placement in 25 patients comparedwith 14 controls. Eighty percent of the subjects were ableto keep the sleeve in place for 12 weeks. Major adverseevents included 3 upper GI bleeds, 1 anchor migration,and 1 stent obstruction. The %EWL at 12 weeks was 22%for the device versus 5% for the controls.30
Future studies are needed to clarify the safety and du-rability of the DJBS. The authors attributed symptoms ofabdominal pain and bloating to a modest amount of tissue
Emerging technology: endoluminal treatment of obesity Cote & Edmundowicz
Figure 5. Transoral gastroplasty (TOGA) sleeve stapler. A, The gastroscope is positioned in retroflexion to visualize the stapler at the gastroesophageal
junction. The retraction wire (arrow) helps to align the greater curvature optimally. B, Endoscopic view demonstrates that the stapler has been opened
and is ready for tissue acquisition by using vacuum pods (arrow). C, With suctioning, the stomach is collapsed, and tissue from the opposing walls is
acquired in the vacuum pods. D, The stapler is closed and fired, creating a full-thickness placation, as shown in E (arrow). Reprinted with permission
from Satiety Inc.
inflammation noted at the duodenal anchor. Can this typeof implant remain intact indefinitely or will this also serveas a precursor to a more definitive surgical intervention?Endoluminal devices used to induce malabsorption arein the earliest phases of development but may offer thegreatest potential in terms of long-term weight loss andcontrol of obesity-related comorbidities.
There is a growing demand for less-invasive approachesto the treatment of obesity. Endoluminal approaches in-cluding prostheses, suturing, and stapling (Table 1) havepromise. However, endoluminal therapies will need tobe held to the same standards of current operative
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Cote & Edmundowicz Emerging technology: endoluminal treatment of obesity
techniques. Each device should be scrutinized in clinicaltrials to determine its safety and efficacy in facilitatingweight loss. In addition to inducing meaningful and sus-tained reductions in BMI, a viable intervention should sig-nificantly reduce the rate of obesity-related comorbidities.Finally, endoluminal treatments will need to have a lastingimpact on weight loss that can be maintained for severalyears after the primary intervention. Retreatment to main-tain weight loss by using relatively benign and inexpensiveendoluminal therapies may need to be tested as a viable
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strategy. There will be particular interest in reversible strat-egies that do not commit the patient to permanent surgi-cal modification of the GI tract. In addition, there may bea role for a trial of an endoluminal intervention to identifycommitted patients for more decisive but costly and po-tentially morbid operative procedures. There is hopethat an effective, easily deployed therapy will be foundto help the millions of people worldwide who are afflictedwith morbid obesity. It is our obligation to carefully andcritically evaluate these devices and allow those that are
Emerging technology: endoluminal treatment of obesity Cote & Edmundowicz
Figure 6. A, A depiction of the GI Dynamics sleeve in place preventing ingested contents from contacting the mucosa of the duodenum and proximal
jejunum. B, The GI Dynamics DJBS (duodenojejunal bypass sleeve). It consists of a nitinol retaining device and a 60-cm plastic sleeve that prevents
contact of food with bile and pancreatic secretions and the mucosa of the duodenum and proximal jejunum. C, The sleeve system is passed over a guide-
wire and then, under direct visualization, the sleeve is deployed over a deeply placed guidewire. D, With the sleeve in place, the retaining device is then
fully deployed in the duodenal bulb to anchor the device. The endoscope is used to visualize placement of the retaining device. E, For retrieval of the
sleeve, a cap is placed at the tip of the upper endoscope. The nitinol retaining device is then grasped with a forceps and brought into the cap. The entire
apparatus is then removed through the mouth. (With permission of GI Dynamics.)
proven safe and effective in this disease to flourish. It is ev-ident that the technological advances leading to these en-doluminal devices have been astounding, and the conceptof endoluminal treatment of obesity is quickly becominga realitydone that we do not want to delay.