C. Prakash Gyawali

Preoperative diagnostic workup before antireflux surgery: An evidence and experience-based consensus of the esophageal diagnostic advisory panel

BACKGROUND Gastroesophageal reflux disease (GERD) is a very prevalent disorder. Medical therapy improves symptoms in some but not all patients. Antireflux surgery is an excellent option for patients with persistent symptoms such as regurgitation, as well as for those with complete symptomatic resolution on acid-suppressive therapy. However, proper patient selection is critical to achieve excellent outcomes. STUDY DESIGN A panel of experts was assembled to review data and personal experience with regard to appropriate preoperative evaluation for antireflux surgery and to construct an evidence and experience-based consensus that has practical application. RESULTS The presence of reflux symptoms alone is not sufficient to support a diagnosis of GERD before antireflux surgery. Esophageal objective testing is required to physiologically and anatomically evaluate the presence and severity of GERD in all patients being considered for surgical intervention. It is critical to document the presence of abnormal distal esophageal acid exposure, especially when antireflux surgery is considered, and reflux-related symptoms should be severe enough to outweigh the potential side effects of fundoplication. Each testing modality has a specific role in the diagnosis and workup of GERD, and no single test alone can provide the entire clinical picture. Results of testing are combined to document the presence and extent of the disease and assist in planning the operative approach. CONCLUSIONS Currently, upper endoscopy, barium esophagram, pH testing, and manometry are required for preoperative workup for antireflux surgery. Additional studies with long-term follow-up are required to evaluate the diagnostic and therapeutic benefit of new technologies, such as oropharyngeal pH testing, multichannel intraluminal impedance, and hypopharyngeal multichannel intraluminal impedance, in the context of patient selection for antireflux surgery.

Impact of Obesity on Bowel Preparation for Colonoscopy

BACKGROUND & AIMS An inadequately cleansed colon can lead to missed lesions, repeat procedures, increased cost, and complications from colonoscopy. Because obesity, with its known link to colorectal neoplasia, might be associated with inadequate bowel cleansing, we investigated the impact of increased body mass index (BMI) on quality of bowel preparation at colonoscopy. METHODS All colonoscopy procedures performed at a tertiary referral center during a 4-month period were evaluated. Bowel preparation was assigned a unique composite outcome score that took into account a subjective bowel preparation score, earlier recommendation for follow-up colonoscopy as a result of inadequate bowel preparation, and the endoscopists confidence in adequate evaluation of the colon. Univariate and multivariate logistic regression analyses were performed to identify the role of BMI in predicting an inadequate bowel preparation. RESULTS During the study period, 1588 patients (59.1% female; mean age, 57.4 +/- 0.34 years) fulfilled inclusion criteria. An abnormal BMI (> or =25) was associated with an inadequate composite outcome score (P = .002). In multivariate logistic regression analyses, both BMI > or =25 (P = .04) and > or =30 (P = .006) were retained as independent predictors of inadequate bowel preparation. Each unit increase in BMI increased the likelihood of an inadequate composite outcome score by 2.1%. Additional independent predictors of inadequate preparation exponentially increased the likelihood of an inadequate composite outcome score; 7 additional risk factors identified 97.5% of overweight patients with an inadequate composite outcome score. CONCLUSIONS Obesity is an independent predictor of inadequate bowel preparation at colonoscopy. The presence of additional risk factors further increases the likelihood of a poorly cleansed colon.

Multiple rapid swallow responses during esophageal high-resolution manometry reflect esophageal body peristaltic reserve.

OBJECTIVES:Dysphagia may develop following antireflux surgery as a consequence of poor esophageal peristaltic reserve. We hypothesized that suboptimal contraction response following multiple rapid swallows (MRS) could be associated with chronic transit symptoms following antireflux surgery.METHODS:Wet swallow and MRS responses on esophageal high-resolution manometry (HRM) were characterized collectively in the esophageal body (distal contractile integral (DCI)), and individually in each smooth muscle contraction segment (S2 and S3 amplitudes) in 63 patients undergoing antireflux surgery and in 18 healthy controls. Dysphagia was assessed using symptom questionnaires. The MRS/wet swallow ratios were calculated for S2 and S3 peak amplitudes and DCI. MRS responses were compared in patients with and without late postoperative dysphagia following antireflux surgery.RESULTS:Augmentation of smooth muscle contraction (MRS/wet swallow ratios >1.0) as measured collectively by DCI was seen in only 11.1% with late postoperative dysphagia, compared with 63.6% in those with no dysphagia and 78.1% in controls (P≤0.02 for each comparison). Similar results were seen with S3 but not S2 peak amplitude ratios. Receiver operating characteristics identified a DCI MRS/wet swallow ratio threshold of 0.85 in segregating patients with late postoperative dysphagia from those with no postoperative dysphagia with a sensitivity of 0.67 and specificity of 0.64.CONCLUSIONS:Lack of augmentation of smooth muscle contraction following MRS is associated with late postoperative dysphagia following antireflux surgery, suggesting that MRS responses could assess esophageal smooth muscle peristaltic reserve. Further research is warranted to determine if antireflux surgery needs to be tailored to the MRS response.

Parameters on Esophageal pH-Impedance Monitoring That Predict Outcomes of Patients With Gastroesophageal Reflux Disease

BACKGROUND & AIMS pH-impedance monitoring detects acid and nonacid reflux events, but little is known about which parameters predict outcomes of different management strategies. We evaluated a cohort of medically and surgically managed patients after pH-impedance monitoring to identify factors that predict symptom improvement after therapy. METHODS In a prospective study, we followed up 187 subjects undergoing pH-impedance testing from January 2005 through August 2010 at Washington University in St. Louis, Missouri (mean age, 53.8 ± 0.9 y; 70.6% female). Symptom questionnaires assessed dominant symptom intensity (DSI) and global symptom severity (GSS) at baseline and at follow-up evaluation. Data collected from pH impedance studies included acid exposure time (AET), reflux exposure time (RET) (duration of impedance decrease 5 cm above lower esophageal sphincter, reported as the percentage of time similar to AET), symptom reflux correlation (symptom index and symptom association probability [SAP]), and the total number of reflux events. Univariate and multivariate analyses were performed to determine factors associated with changes in DSI and GSS after therapy. RESULTS Of the study subjects, 49.7% were tested on proton pump inhibitor (PPI) therapy and 68.4% were managed medically. After 39.9 ± 1.3 months of follow-up, DSI and GSS scores decreased significantly (P < .05). On univariate analysis, an abnormal AET predicted decreased DSI and GSS scores (P ≤ .049 for each comparison); RET and SAP from impedance-detected reflux events (P ≤ .03) also were predictive. On multivariate analysis, abnormal AET consistently predicted symptomatic outcome; other predictors included impedance-detected SAP, older age, and testing performed off PPI therapy. Abnormal RET, acid symptom index, or SAP, and numbers of reflux events did not independently predict a decrease in DSI or GSS scores. CONCLUSIONS Performing pH-impedance monitoring off PPI therapy best predicts response to antireflux therapy. Key parameters with predictive value include increased AET, and correlation between symptoms and reflux events detected by impedance.

EVALUATION OF GI BLEEDING AFTER IMPLANTATION OF LEFT VENTRICULAR ASSIST DEVICE

BACKGROUND Left ventricular assist devices (LVADs) have revolutionized the management of end-stage heart failure (ESHF). However, unexpectedly high rates of GI bleeding (GIB) have been described, and etiology and outcome remain unclear. OBJECTIVE To determine the prevalence, etiology, and outcome of GIB in LVAD recipients. DESIGN Retrospective case series. SETTING Tertiary care academic university hospital. PATIENTS 154 ESHF patients (55.4 years, 122 men/32 women) with LVADs implanted over a 10-year period. MAIN OUTCOME MEASUREMENTS Overt or occult GIB prompting endoscopic evaluation ≥ 7 days after LVAD implantation. RESULTS Over a mean of 0.9 ± 0.1 years of follow-up, 29 patients (19%) experienced 44 GIB episodes. Patients with GIB were older and received anticoagulation therapy before devices were implanted (P ≤ .02 for each). GIB was overt (n = 31) rather than occult (n = 13), and most patients presented with melena (n = 22, 50%); hemodynamic instability was observed in 13.6%. Each bleeding episode required 2.1 ± 0.1 diagnostic or therapeutic procedures, and a source was localized in 71%. Upper endoscopy provided the highest diagnostic yield; peptic bleeding (n = 14) and vascular malformations (n = 8) dominated the findings. Endoscopy was safe and well tolerated. Overall mortality was 35%, none directly from GIB. LIMITATION Retrospective design. CONCLUSIONS Rates of GIB with LVADs are higher than that seen in other patient populations, including those receiving anticoagulation and antiplatelet therapy. GIB episodes are mostly overt and predominantly from the upper GI tract. Endoscopy is safe in the LVAD population.

Learners favour high resolution oesophageal manometry with better diagnostic accuracy over conventional line tracings

Background High resolution manometry (HRM) provides a colourful representation of oesophageal motility. Novice and intermediate learners were tested to compare HRM Clouse plots and conventional manometry for accuracy, ease of interpretation and knowledge retention. Methods 36 learners evaluated 60 randomised motility sequences (30 HRM Clouse plots with corresponding line tracings) 4 months apart, following a tutorial. Learners rated prior knowledge of oesophageal pathophysiology and manometry and scored ease and speed of interpretation on 10 cm visual analogue scales (VAS). Results Understanding of oesophageal pathophysiology was low in all cohorts (2.9±0.4 on VAS) and knowledge of HRM and conventional motility studies was even lower (1.9±0.4 and 1.8±0.3, respectively, p=NS). After the tutorial, diagnostic accuracy was significantly higher with HRM Clouse plots than with line tracings (p<0.001). HRM gains in diagnostic accuracy were evident over line tracings (43.1%), particularly with aperistalsis (36.1%), oesophageal body hypomotility (25.8%) and relaxation of the lower oesophageal sphincter (21.0%) (p<0.001 for each comparison); these were maintained at the second evaluation. Gains were independent of academic level (F=0.56, p=0.5) and did not correlate with prior experience of learners (r=−0.18, p=0.29). Learners favoured HRM Clouse plots (80.6%) over line tracings and reported faster interpretation (94.4%). Conclusions HRM Clouse plots provide ease of interpretation that translates into higher diagnostic accuracy and better knowledge retention in novice and intermediate learners of oesophageal manometry. These results implicate the value of pattern recognition in HRM interpretation, irrespective of academic level and prior understanding of oesophageal motor function.

Impact of Retroflexion Vs. Second Forward View Examination of the Right Colon on Adenoma Detection: A Comparison Study

OBJECTIVES:Although screening colonoscopy is effective in preventing distal colon cancers, effectiveness in preventing right-sided colon cancers is less clear. Previous studies have reported that retroflexion in the right colon improves adenoma detection. We aimed to determine whether a second withdrawal from the right colon in retroflexion vs. forward view alone leads to the detection of additional adenomas.METHODS:Patients undergoing screening or surveillance colonoscopy were invited to participate in a parallel, randomized, controlled trial at two centers. After cecal intubation, the colonoscope was withdrawn to the hepatic flexure, all visualized polyps removed, and endoscopist confidence recorded on a 5-point Likert scale. Patients were randomized to a second exam of the proximal colon in forward (FV) or retroflexion view (RV), and adenoma detection rates (ADRs) compared. Logistic regression analysis was used to evaluate predictors of identifying adenomas on the second withdrawal from the proximal colon.RESULTS:A total of 850 patients (mean age 59.1±8.3 years, 59% female) were randomly assigned to FV (N=400) or RV (N=450). Retroflexion was successful in 93.5%. The ADR (46% FV and 47% RV) and numbers of adenomas per patient (0.9±1.4 FV and 1.1±2.1 RV) were similar (P=0.75 for both). At least one additional adenoma was detected on second withdrawal in similar proportions (10.5% FV and 7.5% RV, P=0.13). Predictors of identifying adenomas on the second withdrawal included older age (odds ratio (OR)=1.04, 95% confidence interval (CI)=1.01–1.08), adenomas seen on initial withdrawal (OR=2.8, 95% CI=1.7–4.7), and low endoscopist confidence in quality of first examination of the right colon (OR=4.8, 95% CI=1.9–12.1). There were no adverse events.CONCLUSIONS:Retroflexion in the right colon can be safely achieved in the majority of patients undergoing colonoscopy for colorectal cancer screening. Reexamination of the right colon in either retroflexed or forward view yielded similar, incremental ADRs. A second exam of the right colon should be strongly considered in patients who have adenomas discovered in the right colon, particularly when endoscopist confidence in the quality of initial examination is low.

Abnormal GERD parameters on ambulatory pH monitoring predict therapeutic success in noncardiac chest pain.

OBJECTIVES:The value of gastroesophageal reflux disease (GERD) indicators (acid exposure time (AET), symptom association probability (SAP), and symptom index (SI)) in predicting therapeutic success in noncardiac chest pain (NCCP) has not been systematically evaluated in outcome studies.METHODS:We retrospectively identified 98 subjects with NCCP (age 51.8±1.2 years, 75 women, mean duration of symptoms 7.3±0.4 years) who underwent pH monitoring off antireflux therapy. Distal esophageal AET (abnormal if ≥4.0%), SAP (measured as Ghillibert probability estimate, abnormal if P<0.05), and SI (abnormal if ≥50%) were calculated; symptom severity and change after therapy were assessed on a 10-point Likert scale. Subjects were interviewed 2.8±0.9 years after the pH study to determine the degree of symptom change (high-degree response (HDR), with definite, sustained symptom improvement) after antireflux therapy. Regression analysis was used to determine the independent predictors of HDR.RESULTS:GERD indicators were present in 61 subjects (62.2%); 52 subjects (53.1%) had abnormal AET, 26 (26.5%) had positive SAP, and 25 (25.5%) had positive SI. With therapy, mean symptom scores improved from 6.3±0.3 at the time of the pH study to 2.9±0.3 at the time of interview (P<0.001). A total of 58 subjects (59.2%) achieved HDR, and another 29.6% had moderate symptom improvement. On univariate analysis, HDR was associated with positive SAP (P=0.003) and elevated AET (P=0.015) but not with demographics, SI, or esophageal motor pattern. In regression analysis containing demographics, GERD indicators, psychiatric comorbidity, and esophageal motor pattern, positive SAP was retained as a significant predictor of HDR (P=0.003); elevated AET trended toward significance (P=0.055). Frequency of HDR was highest when subjects had all three GERD parameters abnormal (93.3% HDR) or both elevated AET and positive SAP (88.2% HDR, P<0.001 compared with only one or no GERD parameter abnormal).CONCLUSIONS:Positive statistical tests of symptom association predict the therapeutic success of GERD management in NCCP. When used hierarchically, response to antireflux therapy is best predicted when GERD parameters are all abnormal and poorest when parameters are normal. These results support the importance of GERD, the relevance of symptom association testing during ambulatory pH monitoring, and the value of intensive antireflux therapy in NCCP.

Diagnosis of esophageal motility disorders: Esophageal pressure topography vs. conventional line tracing

OBJECTIVES:Enhanced characterization of esophageal peristaltic and sphincter function provided by esophageal pressure topography (EPT) offers a potential diagnostic advantage over conventional line tracings (CLT). However, high-resolution manometry (HRM) and EPT require increased equipment costs over conventional systems and evidence demonstrating a significant diagnostic advantage of EPT over CLT is limited. Our aim was to investigate whether the inter-rater agreement and/or accuracy of esophageal motility diagnosis differed between EPT and CLT.METHODS:Forty previously completed patient HRM studies were selected for analysis using a customized software program developed to perform blinded independent interpretation in either EPT or CLT (six pressure sensors) format. Six experienced gastroenterologists with a clinical focus in esophageal disease (attendings) and six gastroenterology trainees with minimal manometry experience (fellows) from three academic centers interpreted each of the 40 studies using both EPT and CLT formats. Rater diagnoses were assessed for inter-rater agreement and diagnostic accuracy, both for exact diagnosis and for correct identification of a major esophageal motility disorder.RESULTS:The total group agreement was moderate (κ=0.57; 95% CI: 0.56–0.59) for EPT and fair (κ=0.32; 0.30–0.33) for CLT. Inter-rater agreement between attendings was good (κ=0.68; 0.65–0.71) for EPT and moderate (κ=0.46; 0.43–0.50) for CLT. Inter-rater agreement between fellows was moderate (κ=0.48; 0.45–0.50) for EPT and poor to fair (κ=0.20; 0.17–0.24) for CLT. Among all raters, the odds of an incorrect exact esophageal motility diagnosis were 3.3 times higher with CLT assessment than with EPT (OR: 3.3; 95% CI: 2.4–4.5; P<0.0001), and the odds of incorrect identification of a major motility disorder were 3.4 times higher with CLT than with EPT (OR: 3.4; 2.4–5.0; P<0.0001).CONCLUSIONS:Superior inter-rater agreement and diagnostic accuracy of esophageal motility diagnoses were demonstrated with analysis using EPT over CLT among our selected raters. On the basis of these findings, EPT may be the preferred assessment modality of esophageal motility.

Queue Position in the Endoscopic Schedule Impacts Effectiveness of Colonoscopy

OBJECTIVES:Endoscopist fatigue potentially impacts colonoscopy. Fatigue is difficult to quantitate, but polyp detection rates between non-fatigued and fatigued time periods could represent a surrogate marker. We assessed whether timing variables impacted polyp detection rates at a busy tertiary care endoscopy suite.METHODS:Consecutive patients undergoing colonoscopy were retrospectively identified. Indications, clinical demographics, pre-procedural, and procedural variables were extracted from chart review; colonoscopy findings were determined from the procedure reports. Three separate timing variables were assessed as surrogate markers for endoscopist fatigue: morning vs. afternoon procedures, start times throughout the day, and queue position, a unique variable that takes into account the number of procedures performed before the colonoscopy of interest. Univariate and multivariate analyses were performed to determine whether timing variables and other clinical, pre-procedural, and procedural variables predicted polyp detection.RESULTS:During the 4-month study period, 1,083 outpatient colonoscopy procedures (57.5±0.5 years, 59.5% female) were identified, performed by 28 endoscopists (mean 38.7 procedures/endoscopist), with a mean polyp detection rate of 0.851/colonoscopy. At least, one adenoma was detected in 297 procedures (27.4%). A 12.4% reduction in mean detected polyps was detected between morning and afternoon procedures (0.90±0.06 vs. 0.76±0.06, P=0.15). Using start time on a continuous scale, however, each elapsed hour in the day was associated with a 4.6% reduction in polyp detection (P=0.005). When queue position was assessed, a 5.4% reduction in polyp detection was noted with each increase in queue position (P=0.016). These results remained significant when controlled for each individual endoscopist.CONCLUSIONS:Polyp detection rates decline as time passes during an endoscopists schedule, potentially from endoscopist fatigue. Queue position may be a novel surrogate measure for operator fatigue.