NORMATIVE VALUES FOR A NEW WATER-PERFUSED HIGH RESOLUTION MANOMETRY SYSTEM

Valores de normalidade de um novo sistema de manometria de alta resolução por perfusão de água

ABSTRACT

BACKGROUND:

Esophageal manometry is the most reliable method to evaluate esophageal motility. High resolution manometry (HRM) provides topographic contour colored plots (Clouse Plots) with simultaneous analysis from the pharynx to the stomach. Both solid state and water-perfused systems are available.

OBJECTIVE:

This study aims to determinate the normative data for a new water-perfused HRM.

METHODS:

HRM was made in 32 healthy volunteers after 8 hours fasting. HRM system used consisted of a 24-channel water-perfused catheter (Multiplex, Alacer Biomedica, São Paulo, Brazil). The reusable catheter is made of polyvinyl chloride (PVC) with 4.7 mm of diameter. Side holes connected to pressure transducers are spaced 2 cm for the analysis from the pharynx to the lower esophageal sphincter (LES). Holes are spaced 5 mm and 120° in a spiral disposition in the LES area. The sensors encompass 34 cm in total. Upper esophageal sphincter (UES) parameters studied were basal and relaxation pressures. Esophageal body parameters were distal contractile integral (DCI), distal latency (DL) and break. LES parameters studied were basal pressure, integrated residual pressure (IRP), total and abdominal length. Variables are expressed as mean ± standard deviation, median (interquartile range) and percentiles 5-95th.

RESULTS:

All volunteers (17 males, aged 22-62 years) completed the study and tolerated the HRM procedure well. Percentiles 5-95th range were calculated: Upper Esophageal Sphincter (UES) basal pressure 16.7-184.37 (mmHg), DL: 6.2-9.1 (s), DCI: 82.72-3836.61 (mmHg.s.cm), break: <7.19 (cm), LES basal pressure: 4.89-37.16 (mmHg), IRP: 0.55-15.45 (mmHg).

CONCLUSION:

The performance and normative values obtained for this low-cost water-perfused HRM seems to be adequate for clinical use.

HEADINGS:
Esophageal motility disorders; Manometry, trends; Low cost technology

RESUMO

CONTEXTO:

Manometria esofágica é o exame mais confiável para avaliar motilidade esofágica. Manometria esofágica de alta resolução (MAER) apresenta um gráfico dinâmico e colorido (Clouse plots) com análise simultânea da faringe ao estomago. Dois tipos de manometria estão disponíveis: estado sólido e por perfusão de água.

OBJETIVO:

Determinar os valores de normalidade de um novo sistema de manometria de alta resolução.

MÉTODOS:

MAER foi realizada em 32 voluntários saudáveis após jejum de oito horas. O sistema utilizado é de perfusão de água com 24 sensores (Multiplex, Alacer Biomedica, São Paulo, Brasil). O catéter permanente é feito de cloreto de polivinil (PVC) com 4,7 mm de diâmetro. Os orifícios laterais para conexão com os transdutores de pressão são espaçados de 2 cm para análise da faringe ao esfíncter esofagiano inferior (EEI) e são esparçados em 5mm em forma espiralada com 120° entre orificios. Os sensores no total englobam 34 cm. Para o esfíncter esofágico superior (EES), os parâmetros estudados foram às pressões basal e de relaxamento. Os parâmetros do corpo esofágico foram: integral de contratilidade distal (DCI), latência distal (DL) e quebra. Os parâmetros do EEI inferior foram pressões basal e de relaxamento e pressão de relaxamento integrada (IRP). As variáveis foram expressas em medias ± desvio padrão, medianas (variação de interquartis) e percentis 5-95.

RESULTADOS:

Todos os voluntários (17 homens, com idade variando entre 22-62 anos) terminaram e toleraram o exame. A variação dos percentis 5-95 foi calculada: pressão basal do esfíncter esofágico superior (EES) foi 16,7-184,37 (mmHg), DL: 6,2-9,1 (s), DCI: 82,72-3836,61 (mmHg.s.cm), quebra: <7,19 (cm), pressão basal do EEI: 4,89-37,16 (mmHg), IRP: 0,55-15,45 (mmHg).

CONCLUSÃO:

A realização dos testes e os valores de normalidade determinados por este estudo parecem ser adequadas para a prática clínica.

DESCRITORES:
Transtornos da motilidade esofágica; Manometria, tendências; Tecnologia de baixo custo

INTRODUCTION

Esophageal Manometry is the most reliable method to evaluate esophageal motility¹. It was introduced in medical practice by the 1940ies with simple systems based on water-filled balloons that evolved to the current high resolution systems². High resolution manometry (HRM) provides topographic contour colored plots (Clouse Plots) with simultaneous analysis from the pharynx to the stomach making the test faster, more comfortable, less susceptible to inter-observer variability, easier to interpret and compensation of movements’ artefacts³.

HRM is based on closely distanced and multiple sensors organized along the probe that varies in number according to different systems^4,5. Both solid state and water-perfused systems are available. This myriad of different configurations demands the determination of reference values according to each technology as has been demonstrated by different studies².

This study aims to determinate the normative data for a new 24 channel water-perfused HRM.

METHODS

Subjects

We studied 32 (17 males, mean age 34 years range 21-62, mean body mass index 24 Kg/m² range 21-32) healthy volunteers. Individuals with upper digestive symptoms in the past 6 months; on drugs that could affect esophageal motility; systemic diseases that can modify esophageal motility; upper digestive tract surgery; or unable to understand the consent form were exclude form the study.

High resolution manometry

All individuals underwent a HRM after 8 hours fasting. The test was performed in left lateral decubitus. After a period for adaptation to the catheter, individuals were instructed to prevent swallowing for a period of 30 seconds in order to acquire resting parameters and subsequently 10 swallows of 5-mL every 30 seconds were offered to acquire dynamic parameters.

HRM system used consisted of a 24-channel water-perfused catheter (Multiplex, Alacer Biomedica, São Paulo, Brazil). The reusable catheter is made of polyvinyl chloride (PVC) with 4.7 mm of diameter. Side holes connected to pressure transducers are spaced 2 cm for the analysis from the pharynx to the lower esophageal sphincter (LES). Holes are spaced 5 mm and 120° in a spiral disposition in the LES area. The sensors encompass 34 cm in total (Figure 1). Perfusion is managed by an original patented controlled peristaltic pump.

FIGURE 1
High resolution manometry water-perfused 24-sensors catheter.

Manometric parameters

Manometric parameters evaluated were those standardized by the International High Resolution Manometry Working Group in 2015, the Chicago classification 3.0⁶. Data was obtained based on automated analysis by the dedicated software (Esofagica v.1492. Alacer Biomedica, São Paulo, Brazil).

Upper esophageal sphincter (UES) parameters studied were basal and relaxation pressures (Figure 2). Esophageal body parameters were distal contractile integral (DCI), distal latency (DL) and break (Figure 3). Lower esophageal sphincter (LES) parameters studied were basal pressure, integrated residual pressure (IRP), total and abdominal length (Figure 4).

FIGURE 2
Manometric parameters for the upper esophageal sphincter (UES). UES basal pressure is determined by the higher pressure within the user determined limits of the sphincter. The measurement is obtained just in one instance in the resting status. Relaxation pressure is determined by the nadir pressure lesser pressure within the user determined limits of the sphincter during swallows. The measurements are performed for all swallows and averaged.

FIGURE 3
Manometric parameters for the esophageal body. Distal latency (DL) is measured the time between the beginning of swallow (upper esophageal sphincter relaxation) to the contractile desaceleration point (CDP) manually determined by the user. CDI is automatically calculated within the area of the user-determined peristaltic wave as the product of the mean amplitude of contraction in the distal esophagus (mmHg) times the duration of contraction (seconds), times the length of the distal esophageal segment (cm) exceeding 20 mmHg for the region spanning from the transition zone to the proximal aspect of the lower esophageal sphincter (LES). Break is calculated by the gap between zones of pressures >20 mmHg within the user-determined defined zone.

FIGURE 4
Manometric parameters for the lower esophageal sphincter (LES). LES basal pressure is determined by the higher pressure within the user determined limits of the sphincter. The measurement is obtained just in one instance in the resting status. Relaxation pressure is determined by the integrated relaxation pressure (IRP) within the user determined limits of the sphincter during swallows. The measurements are performed for all swallows and a median calculated.

Stastistical analysis

Variables are expressed as mean ± standard deviation, median (interquartile range) and percentiles 5-95th.

Ethics

The project was approved by local ethics committee and all participants signed a consent form before entering the study.

The authors are responsible for the study, no professional or ghost writer was hired.

The corresponding author is a consultant for the HRM manufacturer.

RESULTS

Manometric parameters are shown in Table 1.

TABLE 1
Esophageal parameters in healthy volunteers (n=32).

	Mean ± SD	Median	Percentile	Range
		(interquartile 25-75)	5-95 th
Upper esophageal sphincter
Basal pressure - mmHg	77.41±63.13	62.15 (34.1-86.07)	16.7-184.37	12.2-309.3
Relaxation pressure - mmHg	- 6.11±9.63	- 5.4 (-8.25- -2.22)	-20.72- +5.95	- 42.7- +11.4
Esophageal body
DCI - mmHg.s.cm	1868.25±1231.34	1659.35 (992.9-2598.77)	82.72-3836.61	20.8-5261.3
DL - s	7.59±0.94	7.5 (6.85-8.02)	6.2-9.1	6.1-9.2
BREAK - cm	2.58±2.41	2.1 (0.8-4.1)	0.0055-7.19	0-8.1
Lower esophageal sphincter
Basal pressure - mmHg	18.95±9.91	17.5 (12.85-26.65)	4.89-37.16	0.6-40
IRP - mmHg	6±4.91	5.35 (2.75-7.22)	0.55-15.45	0.2-19.9
Total lenght - cm	3.82±0.95	3.75 (3.45-4.5)	2.31-5.43	1.6-5.7
Abdominal lenght - cm	2.19±0.97	2.4 (1.75-2.8)	0.65-3.19	0-5

• DCI - distal contractile integral. DL - distal latency. IRP - integrated residual pressure.

DISCUSSION

HRM has proven advantages over conventional manometry⁷. Solid state HRM systems have a faster response to changes in pressure and circumferential disposition of sensors² but a higher cost. These characteristics allow better evaluation of striated muscles⁸ and sphincters relaxation⁹. Water-perfused HRM systems are cheaper and may be adequate for routine clinical practice^5,10-12. It is worth remembering that most of the conventional manometry equipment used a water-perfused system¹³. The number of sensors; however, may be limited by the diameter of water-perfused catheters. Most current systems adopted a HRM sensor disposition - i.e. circumferential sensors closely spaced - limited to the LES area². The asymmetry of the LES imposes a circumferential disposition in this zone forcing the use of most of the sensors available in this part of the catheter.

The system tested in this study employs a spiral disposition of the sensors. This original configuration was developed to allow a radial evaluation of the LES and save sensors to be used for the esophageal body and UES. Other studies that defined normative values employed only two different commercial systems that use 22 or 36 sensors disposed every 1 cm in the areas measuring the LES, and every 2 cm in the areas measuring the esophageal body, similar to our equipment, but with a radial distribution of distal sensors^5,10,12.

The colorful intuitive panoramic view of the esophageal motility provided by HRM stimulated the human eyes to distinguish subtle parameters unknown or uncomprehend so far¹⁴ culminating with the Chicago Classification that defined the current parameters used for the evaluation of esophageal motility⁶. UES was neglected on the 3.0 version of the Chicago classification with a promised inclusion on the next version⁶. In our study, UES was detected and analyzed in all cases. Our system performed visually similar to solid-state equipment with a centrifuge decrease of pressure but well-defined borders. The limitation of the non-circumferential analysis in this area is yet to be proven, as the UES pressures are also asymmetrical radially¹⁵. Detailed visualization of the structures of the pharynx was not possible as compared to solid state systems⁸.

Esophageal body contractions are symmetrical radially. The lack of radial sensors in our low-cost system for the esophageal body area does not preclude a detailed analysis of this segment. Sensors are; however, 2 cm spaced, not 1 cm as usual in solid-state systems. Segmental defects of peristalsis (fragmented peristalsis) are rare in routine clinical practice and long peristaltic gap in the transition zone (break) is considered pathologic if over 5 cm³, thus amenable to detection by the tested system. The determination of the contractile deceleration point (CDP) - necessary to define the DL - may have a ± 1 cm error, what we believe is also not clinically significant. Interestingly, all water-perfused systems have similar normal values for DL (Table 2) and higher than the solid-state systems². This may be explained by the retarded response sensors due to the delay in pressure transmission along the water-systems as compared to solid-state transducers.

TABLE 2
Normative values for water-perfused high resolution esophageal manometry systems.

	Current study	Tseng et al.	Kessing et al.	Burgos Santamaria et al.	Capovilla et al.
Number of volunteers	32	66	50	16	20
Catheter (number of sensors)	24	22	36	22	24
DCI - mmHg.s.cm	83-3837	99-2186	142-3.674	285-2.280	557-1.726
DL - s	>6.2	>6.2	>6.2	>6.1	>7.0
LES basal pressure - mmHg	5-37	8.7-46.5	<18.8	<54	NA
IRP - mmHg	<16	<20	<29.8	<20	<8.8
break - cm	>7cm	0-13.4	NA	NA	NA

• LES: lower esophageal sphincter; DCI: distal contractile integral; DL: distal latency; IRP: integrated residual pressure.

A reliable assessment of the relaxation of the LES is probably the best contribution of HRM^7,16. The concentration of sensors provided by the technology compensates for motion artifacts avoiding erroneous interpretation of LES pseudo-relaxation¹⁷ and allows a more sophisticated parameter to evaluate relaxation in opposition to nadir pressure only, the IRP¹⁶. Water-perfused systems present a variable number of sensors distally in the probe but closely space to provide this advantage of HRM. The system evaluated in the current study differs from other water-perfused equipment due to a spiral disposition of the sensors. Our results of the LES are within the range of values found for different water-perfused systems.

This study evaluated a small number of volunteers due to the difficult in recruiting healthy individuals to an uncomfortable test. Also, normative values were not validated in patients yet. A study is in progress and it will include patients with well-established achalasia and other LES disorders to demonstrate that the threshold found for IRP (a sensitive parameter to be evaluated in new systems) is clinically valuable. Despite these limitations, the performance and normative values obtained for this low-cost water-perfused HRM seems to be adequate for clinical use.

ACKNOWLEDGMENTS

We are indebted to Ms. Vanessa Tuxen for her invaluable assistance with the esophageal tests.

REFERENCES

• ¹
  Jobe BA, Richter JE, Hoppo T, Peters JH, Bell R, Dengler WC, et al. Preoperative diagnostic workup before antireflux surgery: an evidence and experience based consensus of the Esophageal Diagnostic Advisory Panel. J Am Coll Surg. 2013;217:586-97.
• ²
  Herregods TV, Roman S, Kahrilas PJ, Smout AJ, Bredenoord AJ. Normative values in esophageal high-resolution manometry. Neurogastroenterol Motil. 2015;27:175-87.
• ³
  Schlottmann F, Herbella FA, Patti MG. Understanding the Chicago Classification: From Tracings to Patients. J Neurogastroenterol Motil . 2017;234:487-94.
• ⁴
  Smout AJ. Manometry of the gastrointestinal tract: toy or tool? Scand J Gastroenterol Suppl. 2001;234:22-8.
• ⁵
  Kessing BF, Weijenborg PW, Smout AJ, Hillenius S, Bredenoord AJ. Water-perfused esophageal high-resolution manometry: normal values and validation. Am J Physiol Gastrointest Liver Physiol. 2014;306:G491‐5.
• ⁶
  Kahrilas PJ, Bredenoord AJ, Fox M, Gyawali CP, Roman S, Smout AJ, et al. The Chicago Classification of esophageal motility disorders, v3.0. Neurogastroenterol Motil . 2015;27:160-74.
• ⁷
  Salvador R, Dubecz A, Polomsky M, Gellerson O, Jones CE, Raymond DP, et al. A New Era in Esophageal Diagnostics: The Image-Based Paradigm of High-Resolution Manometry. J Am Coll Surg . 2009;208:1035-44.
• ⁸
  Silva LC, Herbella FA, Neves LR, Vicentine FP, Neto SP, Patti MG. Anatomophysiology of the Pharyngo-Upper Esophageal Area in Light of High-Resolution Manometry. J Gastrointest Surg. 2013:17:2033-8.
• ⁹
  Gehwolf P, Hinder RA, DeVault KR, Edlinger M, Wykypiel HF, Klingler PJ. Significant pressure differences between solid-state and water-perfused systems in lower esophageal sphincter measurement. Surg Endosc. 2015:2912:3565-9.
• ¹⁰
  Burgos-Santamaría D, Marinero A, Chavarría-Herbozo CM, Pérez-Fernández T, López-Salazar TR, Santander C. Normal values for waterperfused esophageal high-resolution manometry. Rev Esp Enferm Dig. 2015;107:354‐8.
• ¹¹
  Capovilla G, Savarino E, Costantini M, Nicoletti L, Zaninotto G, Salvador R. Inter-rater and interdevice agreement for the diagnosis of primary esophageal motility disorders based on Chicago Classification between SolidState and Water-Perfused HRM System- A Prospective, Randomized, Double Blind, Crossover Study. Gastroenterology. 2014;146:S‐681.
• ¹²
  Tseng PH, Wong RKM, Wu JF, Chen CC, Tu CH, Lee YC. Normative values and factors affecting water-perfused esophageal high-resolution impedance manometry for a Chinese population. Neurogastroenterol Motil . 2018;30:e13265.
• ¹³
  Sweet MP, Herbella FAM, Leard L, Hoopes C, Golden J, Hays S, et al. The prevalence of distal and proximal gastroesophageal reflux in patients awaiting lung transplantation. Ann Surg. 2006;244:491-7.
• ¹⁴
  Herbella FA, Patti MG. Can high resolution manometry parameters for achalasia be obtained by conventional manometry?. World J Gastrointest Pathophysiol. 2015;6:58-61.
• ¹⁵
  Meyer JP, Jones CA, Walczak CC, McCulloch TM. Three-dimensional manometry of the upper esophageal sphincter in swallowing and nonswallowing tasks. Laryngoscope. 2016;126:2539-45.
• ¹⁶
  Lafraia FM., Herbella FAM., Kalluf JR., Patti MG. A pictorial presentation of esophageal high resolution manometry current parameters. Arq Bras Cir Dig. 2017;30:69-71.
• ^17.
  Katz PO, Richter JE, Cowan R, Castell DO. Apparent Complete Lower Esophageal Sphincter Relaxation in Achalasia. Gastroenterology. 1986;90:978-83.

• Disclosure of funding: no funding received

Publication Dates

• Publication in this collection
  Nov 2018

History

• Received
  22 Feb 2018
• Accepted
  03 Apr 2018