DIAGNOSTIC PROCEDURES in GERD: PRINCIPLES and VALUES of ESOPHAGEAL MANOMETRY and Ph-MONITORING

Chapter 11 DIAGNOSTIC PROCEDURES IN GERD: PRINCIPLES AND VALUES OF ESOPHAGEAL MANOMETRY AND pH-MONITORING R. Tutuian and D. O. Castell Division of Gastroenterology – Hepatology, Medical University of South Carolina, Charleston, SC, USA Introduction Gastroesophageal reflux disease (GERD) is a highly and is currently considered the gold standard prevalent disease in industrialized countries. In the US to diagnose esophageal motility abnormalities. alone, 40% of the adult population frequently com- Esophageal manometry provides information on plains of heartburn, one of the cardinal symptoms of amplitude and coordination of esophageal contrac- GERD [1]. In a recent study by Sandler et al [2] gas- tions and the relaxation and coordination of the troesophageal reflux disease (GERD) has been report- upper and lower esophageal sphincter. Simulta- ed to be the 4th most prevalent GI disease in the US neous video-fluoroscopy and manometry studies (19 million cases/year), being surpassed only by non- have been used to document bolus transit depen- food-borne gastroenteritis and other gastrointestinal dence on esophageal peristalsis (Fig. 1) [5]. Even infections (135 million cases/year), food-borne illness though it is not used to primarily diagnosed (76 million cases/year) and cholelithiasis (20 million GERD, esophageal manometry is frequently used cases/year). In the same study, GERD was found to be in patients with GERD in order to support the the most costly gastrointestinal disease with direct and diagnosis in a complex patient, to evaluate patients indirect costs estimated at $ 9.8 billion 1998 US with atypical symptoms, to detect defective peri- Dollars, surpassing the costs of treatment for choleli- stalsis prior to fundoplication, to exclude sclero- thiasis ($5.8 billions), colorectal cancer ($4.9 billions) derma or achalasia as cause of the patient’s and peptic ulcer disease ($3.1 billions). symptoms and to assist placing of pH-probes. Reflux esophagitis, a term first introduced by Allison [3] in 1946, was considered for many years to provide the evidence of gastroesophageal disease. As clinicians became more familiar with the spectrum of GERD it became clear that esophageal symptoms (heartburn, regurgitation, dysphagia, chest pain, etc.) might be caused by gastroesophageal reflux in the absence of endoscopic evidence of esophageal lesions. With this understanding it became clear that other tests for the diagnosis of GERD were needed. Over time esophageal manometry, pH monitoring and more recently multichannel intraluminal impedance (MII) combined with pH (MII-pH) were added to the clinical armamentarium to diagnose GERD. Fig. 1. Manometric/videofluoroscopic comparison during normal swallows. Schematic representation of esophageal peristalsis as measured by manometry corresponding to the Esophageal manometry time when the barium column is advancing through the esophagus.The timings (in sec) indicate that effective peristal- Esophageal manometry has been used as a diagno- tic contractions are responsible for bolus transit through the stic test for esophageal disease for over 40 years [4] esophagus 122 Chapter 11 Esophageal manometry equipment Performing esophageal manometry Esophageal manometry is usually performed as an out- The main components of a manometry system are patient procedure and patients are requested to fast for (1) the esophageal manometry catheter, (2) pres- at least 4–6 hours prior to testing. After calibrating the sure transducers, (3) signal acquisition, and (4) esophageal manometry catheter outside the patient, the information storage devices. The majority of tube is typically inserted transnasally after applying vis- esophageal laboratories use either water-perfused cous lidocaine to decrease the discomfort as the cathe- catheters with external transducers or catheters ter passes the nasal cavity. The esophageal catheter is with solid-state transducers. Water perfused sys- advanced into the stomach where gastric baseline pres- tems include a thin, flexible catheter with small sures are measured as reference and then slowly pulled capillary orifices connected to an external water back (stationary pull-through) to identify the lower supply and pump and external pressure trans- esophageal sphincter. Depending on the configuration ducers. The pressure measured by external, water- of the catheter LES dynamics and esophageal body ac- column, transducers reflects the pressure that the tivity can be measured during the same or during sepa- water pump has to generate in order to overcome rate swallows. In our laboratory we use a solid-state the pressure with which the esophageal wall oc- transducer catheter that allows evaluation of esopha- cludes the capillary orifice. These systems have geal peristalsis and LES relaxation during the same the advantage of relatively low-cost catheters but swallow (Fig. 2). Once the catheter is placed in the have the disadvantage of requiring additional right position ten 5 ml swallows are administered at equipment (water supply, pump) and are more 20–30 second intervals and the subject is asked to difficult to operate and maintain. Another disad- swallow once. The 20–30 second interval is necessary vantage of water-perfused systems is that the to avoid falsely low contraction amplitudes determined external, water-column transducers require the by deglutitive inhibition. Double swallow and/or patient’s body to be aligned with the pressure sensors, often limiting esophageal motility testing to the recumbent position. Solid-state transducer systems include equally thin, flexible catheters with pressure transducers mounted directly on the catheter. The solid-state transducers use small, oil-filled chambers with extremely high compliance to transmit esophageal pressure to miniature sensors incorporated in the catheter. The increased cost of solid-state transducer catheters is compensated by easier, more convenient operability of the system without additional equipment (pumps and supplies). Solid-state transducer systems can also be used for ambulatory monitoring and motility testing in upright positions. Signal acquisition devices consist of sets of am- plifiers and converters while, these days, computer systems have long replaced polygraphs as data stor- Fig. 2. Solid-state sensor esophageal manometry catheter. age devices. The distal pressure transducer has a circumferential sensor In addition to this primary equipment certain collecting 360 degrees data from the lower esophageal smaller equipment (calibration chamber) and sec- sphincter. Unidirectional sensors placed in the esophagus ondary consumable supplies (disinfection and ster- 5, 10 and 15 cm above the LES allow measurement of esoph- ilization materials, tape, lubricating gel, viscous ageal peristalsis. This system allows measuring esopha- lidocaine, emesis basins, syringes, testing substances, geal body peristalsis and LES relaxation during the same etc.) are needed to perform esophageal manometry. swallow Tutuian R and Castell DO 123 Fig. 3 (continued) 124 Chapter 11 Fig. 3 (continued) Tutuian R and Castell DO 125 Interpreting esophageal manometry The interpretation of esophageal manometry data is based on comparing information about swallows against data collected in normal volunteers [6]. It is important to recognize that different laboratories may use slightly different manometric criteria based on their individual experience. In our laboratory, individual swallows are classified as normal peristaltic if their contraction amplitude exceeds 30 mmHg in the distal esophagus and the velocity of the contraction onset does not exceed 8 cm/sec. Swallows are declared ineffective if the contraction amplitude is less than 30 mmHg in the distal esophagus. This definition allows including in the manometric ineffective category swallows classified by other authors as “failed peristalsis” or “non-transmitted”. Swallows Fig. 3. Manometric diagnoses: (a) Achalasia is defined by are classified as manometric simultaneous if their absent esophageal body peristalsis and, if present, poorly relaxing LES. (b) Scleroderma is defined based on an appro- amplitude exceeds 30 mmHg in the distal esophagus priate clinical diagnosis and confirmed by low amplitude or and have a simultaneous or retrograde onset of con- absent contractions in the distal esophagus with or without traction or the velocity of the contraction onset in a low LES pressure. (c) Distal esophageal spasm is defined as the distal esophagus exceeds 8 cm/sec. 20% or more simultaneous contractions. (d) Ineffective esoph- For the overall interpretation of manometric findings ageal motility is defined as 30% or more swallows with we recommend using criteria published by Spechler and contraction amplitude less than 30 mmHg in either of the Castell [7] (Fig. 3). Achalasia is defined by absent two distal sites located at 5 and 10 cm above the LES. esophageal body peristalsis and, if present, poorly relax- (e) Nutcracker esophagus is defined as normal peristalsis of ing and hypertensive LES. Patients with GERD may the esophageal body with average distal esophageal am- have a variety of esophageal manometric abnormalities, plitude (DEA) exceeding 180 mmHg. (f) Poorly relaxing LES low amplitude contractions (i.e., ineffective esophageal is defined as average LES residual pressure exceeding motility; IEM) being particularly frequent. Abnormal 8 mmHg associated with normal esophageal body contractions. (g) Hypertensive LES is defined as LES resting esophageal acid exposure has also been associated

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