Making the Most of Imperfect High-Resolution Manometry Studies
2011; Elsevier BV; Volume: 9; Issue: 12 Linguagem: Inglês
10.1016/j.cgh.2011.09.024
ISSN1542-7714
Autores Tópico(s)Eosinophilic Esophagitis
ResumoHigh-resolution manometry (HRM) incorporates 2 major advances in pressure measurement within hollow viscus: increased numbers of sensing units on manometry catheters and computerized data management that fills points in between pressure recordings with best-fit data.1Kahrilas P.J. Esophageal motor disorders in terms of high resolution esophageal pressure topograph: what has changed.Am J Gastroenterol. 2010; 105: 981-987Crossref PubMed Scopus (91) Google Scholar, 2Clouse R.E. Prakash C. Topographic esophageal manometry: an emerging clinical and investigative approach.Dig Dis. 2000; 18: 64-74Crossref PubMed Scopus (61) Google Scholar The final image is a color-coded pressure topograph, now universally termed Clouse plot in honor of Ray Clouse, who pioneered HRM.1Kahrilas P.J. Esophageal motor disorders in terms of high resolution esophageal pressure topograph: what has changed.Am J Gastroenterol. 2010; 105: 981-987Crossref PubMed Scopus (91) Google Scholar Several gains are evident over previously used conventional manometry; anatomic landmarks are easier to identify, data acquisition is shorter for both patient and operator, assessment of esophageal sphincter function is more accurate and specific, and motor patterns are overall easier to recognize.1Kahrilas P.J. Esophageal motor disorders in terms of high resolution esophageal pressure topograph: what has changed.Am J Gastroenterol. 2010; 105: 981-987Crossref PubMed Scopus (91) Google Scholar, 2Clouse R.E. Prakash C. Topographic esophageal manometry: an emerging clinical and investigative approach.Dig Dis. 2000; 18: 64-74Crossref PubMed Scopus (61) Google Scholar Despite these advances, not all HRM studies are pristine and perfect. In this issue, Roman et al3Roman S. Kahrilas P.J. Boris L. et al.High resolution manometry studies are frequently imperfect but usually still interpretable.Clin Gastroenterol Hepatol. 2011; 9: 1050-1055Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar report that as many as one-fifth of the studies performed at a major esophageal motility center have imperfections. However, many of these are soft imperfections, and useful information can still be obtained. A study is critically imperfect if no useful data are obtained, which can result from technical malfunction or from patient-related factors. The authors report a 1.5% incidence of sensor or other technical malfunction in their series; although some of these could be critical, individual sensors can be turned off and analysis completed in many instances. Consequently, studies were nondiagnostic and therefore critically imperfect in only 27 cases (1.4% of the total) in the current report.3Roman S. Kahrilas P.J. Boris L. et al.High resolution manometry studies are frequently imperfect but usually still interpretable.Clin Gastroenterol Hepatol. 2011; 9: 1050-1055Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar Our group has similarly reported critical imperfections in only 2.0% of 1103 HRM studies performed with a prototype water-perfused HRM catheter,4Chan W.W. Haroian L.R. Gyawali C.P. Value of preoperative esophageal function studies before laparoscopic antireflux surgery.Surg Endosc. 2011; 25: 2943-2949Crossref PubMed Scopus (92) Google Scholar compared with 5.0% of 1223 conventional manometry studies performed between 1987 and 19965Alrakawi A. Clouse R.E. The changing use of esophageal manometry in clinical practice.Am J Gastroenterol. 1998; 93: 2359-2362Crossref PubMed Scopus (31) Google Scholar; none of the available reports include aborted procedures. Current solid-state HRM systems provide real-time Clouse plots for the operator to view as the procedure is performed, allowing the operator to abort or modify the study when multiple sensors malfunction or if critical patient-related factors (extreme gagging, aspiration, inability to traverse the nasal passages or upper esophageal sphincter, inability to tolerate the catheter) are encountered. Therefore, the likelihood of complete study failure is lower than with conventional manometry or older HRM systems. The current study does not report the incidence of critical failures prompting aborting of the procedure, but these are likely infrequent in high-volume centers with experienced operators compared with those with less volume. Inability to traverse the esophagogastric junction (EGJ) can be a critical imperfection, especially if the lower esophageal sphincter (LES) is not traversed. Although aperistalsis with isobaric pressure elevation in the esophageal body suggests esophageal outflow obstruction, an abnormally relaxing LES is required for the diagnosis of achalasia, and this diagnosis can only be suspected without LES metrics. In such instances, endoscopy and barium studies complement history and whatever information is available from HRM for a conclusive diagnosis. It is reassuring to note that the accuracy of achalasia diagnosis with imperfect studies is similar to that achieved with perfect studies in the current study, 92%–94%.3Roman S. Kahrilas P.J. Boris L. et al.High resolution manometry studies are frequently imperfect but usually still interpretable.Clin Gastroenterol Hepatol. 2011; 9: 1050-1055Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar An experienced operator makes all the difference and needs to recognize curling or doubling back of the catheter when a "butterfly" pattern of recurring pressure bands is seen, so that clinical maneuvers to reposition the catheter (Table 1) are used, or a recommendation for endoscopic placement is made. If the LES is traversed but the diaphragmatic crura are not (ie, the catheter tip is within a hiatus hernia rather than the stomach), LES function and esophageal body peristalsis can still be addressed. Therefore, this is usually a soft and noncritical imperfection, which has been encountered 6% of the time by the authors.3Roman S. Kahrilas P.J. Boris L. et al.High resolution manometry studies are frequently imperfect but usually still interpretable.Clin Gastroenterol Hepatol. 2011; 9: 1050-1055Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar However, because LES post-swallow residual pressures are measured over the gastric baseline, numeric LES metrics could be erroneous if pressure within the hiatus hernia is higher than the true gastric baseline. This is fortunately relatively rare, and the authors report only 7 instances in their series (0.35%) wherein abnormal LES relaxation was suspected in this manner.3Roman S. Kahrilas P.J. Boris L. et al.High resolution manometry studies are frequently imperfect but usually still interpretable.Clin Gastroenterol Hepatol. 2011; 9: 1050-1055Abstract Full Text Full Text PDF PubMed Scopus (45) Google ScholarTable 1Maneuvers for Reducing ImperfectionsImperfectionManeuverLimited sensor malfunctionRepeat pressure and thermal calibrationTurn off aberrant sensor(s)Inability to traverse nasal passageTopical lidocaine gel application to nasal passagesNasal decongestant sprayGagging, repeated swallowingReassurance, relaxation exercises such as deep breathingPatient is asked to open mouthPatient is asked to watch Clouse plots on screenPatient squeezes on soft ball or toyPatient focuses on particular focal point in the roomInability to traverse LESPatient stands up to straighten tortuosity in esophagusPatient raises hands over headOperator inserts 45°–90° twist along long axis of catheterPatient takes repeated or big gulps of wateraMultiple rapid swallows result in more profound LES relaxation.Placement under endoscopic guidanceInability to traverse diaphragmatic cruraPatient stands up to reduce axial hiatus herniaPlacement under endoscopic guidanceProminent vascular or respiratory artifactPatient is repositioned with a slight tilt of the body toward the lefta Multiple rapid swallows result in more profound LES relaxation. Open table in a new tab Insufficient complements of properly performed wet swallows were the most common imperfection reported (58% of imperfect studies, 12.1% of total studies).3Roman S. Kahrilas P.J. Boris L. et al.High resolution manometry studies are frequently imperfect but usually still interpretable.Clin Gastroenterol Hepatol. 2011; 9: 1050-1055Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar This category includes inability to complete the swallow protocol, inability to withhold swallowing, gagging, belching, and multiple swallowing. Although the authors used 7 adequate wet swallows as the cutoff for adequacy in their series, clinically useful impressions can be reached with as few as 5 swallows in many instances, especially in terms of LES relaxation.6Murray J.A. Clouse R.E. Conklin J.L. Components of the standard oesophageal manometry.Neurogastroenterol Motil. 2003; 15: 591-606Crossref PubMed Scopus (81) Google Scholar Achalasia accounted for one-third of patients with incomplete wet swallows, a diagnosis that could probably be made accurately with <7 swallows.3Roman S. Kahrilas P.J. Boris L. et al.High resolution manometry studies are frequently imperfect but usually still interpretable.Clin Gastroenterol Hepatol. 2011; 9: 1050-1055Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar, 6Murray J.A. Clouse R.E. Conklin J.L. Components of the standard oesophageal manometry.Neurogastroenterol Motil. 2003; 15: 591-606Crossref PubMed Scopus (81) Google Scholar Therefore, insufficient wet swallows can be considered a soft imperfection. Similarly, vascular artifacts are generally soft imperfections and do not impact the overall analysis. When encountered, the operator makes adjustments to the protocol to obtain as much useful information as possible (Table 1). By using clinical history and context, Roman et al3Roman S. Kahrilas P.J. Boris L. et al.High resolution manometry studies are frequently imperfect but usually still interpretable.Clin Gastroenterol Hepatol. 2011; 9: 1050-1055Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar demonstrate that useful information can be gleaned from most imperfect studies, and only <1.5% of their total cohort had truly nondiagnostic studies. This is clearly an advantage specific to HRM over conventional studies. What has not been addressed is whether pattern recognition of peristaltic events contributed to analysis in imperfect situations. Esophageal body and LES peristaltic patterns are frequently characteristic for normal, hypermotile, and hypomotile patterns, and conclusions can be reached from visual inspection of Clouse plots even if numeric values are unavailable.2Clouse R.E. Prakash C. Topographic esophageal manometry: an emerging clinical and investigative approach.Dig Dis. 2000; 18: 64-74Crossref PubMed Scopus (61) Google Scholar, 7Soudagar A.S. Sayuk G.S. Gyawali C.P. Learners favor high resolution esophageal manometry with better diagnostic accuracy over conventional line tracings.Gut. 2011; (in press)Google Scholar Even with novice and intermediate-level evaluators, pattern recognition without use of software tools allows accurate diagnosis of major motor patterns in more than two-thirds of cases7Soudagar A.S. Sayuk G.S. Gyawali C.P. Learners favor high resolution esophageal manometry with better diagnostic accuracy over conventional line tracings.Gut. 2011; (in press)Google Scholar; expert reviewers can likely do much better. The biggest contribution of the current study is that imperfections are now well-characterized, and attention can now shift to predicting and managing limitations during the study. For instance, prior foregut surgery alters anatomy and makes the procedure challenging3Roman S. Kahrilas P.J. Boris L. et al.High resolution manometry studies are frequently imperfect but usually still interpretable.Clin Gastroenterol Hepatol. 2011; 9: 1050-1055Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar; therefore extra care is needed. At the very least, the operator should be trained to recognize the normal Clouse plot and understand rudimentary EGJ pressure mechanics; knowledge and experience with specific maneuvers to overcome imperfections is desirable (Table 1). Endoscopic placement might be absolutely necessary when LES relaxation needs to be characterized and should be recognized. This can be cumbersome and might not always be successful, especially with large hiatus hernias.3Roman S. Kahrilas P.J. Boris L. et al.High resolution manometry studies are frequently imperfect but usually still interpretable.Clin Gastroenterol Hepatol. 2011; 9: 1050-1055Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar At our center, the HRM catheter is first calibrated, and the acquisition program is kept running, while the catheter is disconnected and taken to the endoscopy suite. Endoscopy is performed with monitored anesthesia (with propofol), avoiding benzodiazepines and narcotics. The endoscope is first inserted to determine esophageal anatomy. The endoscope is then withdrawn to the oropharynx; the sheathed HRM catheter is introduced through the nostril and inserted until resistance or bowing is encountered. The endoscope is then inserted into the esophagus, and the endoscope tip is used to deflect the HRM catheter toward the EGJ. Use of a snare is discouraged, because this can damage sensors on the catheter. Multiple sensors are left within the stomach in case the catheter becomes partially pulled back with endoscope removal, and the catheter is taped to the nostril. After the patient is fully awake, the catheter is repositioned so both sphincters and EGJ are clearly visible, and the study is performed. A common theme in the discussion above is the importance of a clinically astute operator who can manage simple problems with catheter placement and adequate swallows, and abort if critical imperfections are encountered. Now more than ever, nurses and technicians need to be targeted for specific training, because they are the ones who will ensure imperfections are prevented or resolved in real time. Nevertheless, HRM clearly allows easier recognition of underlying motor patterns even when technically imperfect, and critical imperfections are infrequent. If interpretation takes study context into consideration, major motor patterns can be correctly diagnosed despite imperfections, and achalasia diagnosis in particular does not suffer. As we continue to make the most of technically imperfect HRM studies, we should also focus attention to factors under operator control to reduce imperfect studies. High-Resolution Manometry Studies Are Frequently Imperfect but Usually Still InterpretableClinical Gastroenterology and HepatologyVol. 9Issue 12PreviewClinical esophageal manometry can be technically challenging. We investigated the prevalence and causes of technically imperfect, high-resolution esophageal pressure topography (EPT) studies at a tertiary referral hospital. Full-Text PDF
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