Use of high-resolution endoluminal sonography to measure the radius and wall thickness of esophageal varices

Schiano, Thomas D.; Adrain, Alyn L.; Cassidy, Michael J.; McCray, William; Liu, Ji‐Bin; Baranowski, Robert J.; Bellary, Somashekhar; Black, Martin M.; Miller, Larry S.

doi:10.1016/s0016-5107(96)70093-7

Cited by 44 publications

(14 citation statements)

References 9 publications

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“…Studies are in progress in our laboratory to determine the accuracy of the ultrasound technique to determine the varix pressure in vivo. Furthermore, the ultrasound technique can determine varix wall thickness and radius, two other variables required to determine varix wall stress, the parameter likely to be the most important predictor of variceal rupture (21).…”

Section: Discussionmentioning

confidence: 99%

Ultrasound system to measure esophageal varix pressure: an in vitro validation study

Puckett¹,

Liu²,

Bhalla³

et al. 2005

American Journal of Physiology-Gastrointestinal and Liver Physi

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. Ultrasound system to measure esophageal varix pressure: an in vitro validation study. Am J Physiol Gastrointest Liver Physiol 288: G914-G919, 2005. First published December 30, 2004; doi:10.1152/ajpgi.00373.2004.-We report our experience with an ultrasound system to measure esophageal varix pressure in an in vitro model. The ultrasound system consists of a 12.5 MHz frequency intraluminal ultrasound probe, a water infusion catheter, and a manometry catheter, all contained within a nondistensible latex bag. Esophagi and external jugular veins were harvested from five pigs. The vein and ultrasound system were placed inside the esophagus. One end of the vein was connected to a water reservoir to modulate its pressure; the other end was connected in two different ways to simulate hydrodynamic and hydrostatic flow conditions. The bag was inflated with water until vein occlusion was discernible on the ultrasound images. The influences of vein pressure, vein cross-sectional area and esophageal elasticity on the ultrasound measurement of vein pressure were assessed. A total of 108 trials were performed at nine different vein pressures. Complete vein occlusion occurred when the bag pressure was slightly greater (1.4 Ϯ 0.7 mmHg) than the vein pressure. For a vein pressure of 25 mmHg, the average occlusion and opening pressures were 27 Ϯ 0.2 and 25.7 Ϯ 0.3 mmHg, respectively (P Ͻ .05) suggesting that the vein opening pressure on the ultrasound images is more accurate than the vein closing pressure. In conclusion, the ultrasound technique can accurately measure intravariceal pressure in vitro. The bag pressure at the point of vein reopening is the best determinant of the vein pressure. portal hypertension; variceal pressure; ultrasonography; noninvasive technique; variceal bleed BLEEDING FROM ESOPHAGEAL VARICES is a major complication of liver cirrhosis and portal hypertension. Approximately onethird of patients with varices will experience an episode of bleeding over a 2-yr period. Mortality from the first bleeding episode ranges from 30 to 50%. The major predictors of bleeding are the hepatic venous pressure gradient (HVPG), severity of underlying liver disease, varix size, and stigmata of variceal bleed (red color sign) (North Italian Endoscopic Club) (6). The least subjective of these parameters is the HVPG. Esophageal varices bleed only when the HVPG is Ն12 mmHg. However, when the HVPG is Ͼ12 mmHg, there is not a direct relationship between the HPVG and bleeding. Therefore, on the basis of the HVPG measurement, it has been difficult to predict which patient will bleed from the varices. Furthermore, the HPVG measurement technique is invasive.Varix wall stress is considered to be the primary determinant of its rupture. In accordance with Laplace's equation for the circumferential wall stress, ϭ (P⅐r)/t, the determinants of the variceal wall stress () are the varix radius (r), varix pressure (P) and varix wall thickness (t) (3-5, 9, 16). The measurement of variceal pressure has been attempted by a number of investigators...

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Section: Discussionmentioning

confidence: 99%

Ultrasound system to measure esophageal varix pressure: an in vitro validation study

Puckett¹,

Liu²,

Bhalla³

et al. 2005

American Journal of Physiology-Gastrointestinal and Liver Physi

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“…The simultaneous ultrasound and manometry device, used in this study to measure variceal pressure during peristaltic contraction, is based on prior work using high resolution endoluminal ultrasound (4,5,8,9,11,13,14) and simultaneous ultrasound and manometry to evaluate esophageal motility (6,10,15,16).…”

Section: Discussionmentioning

confidence: 99%

Mechanics and hemodynamics of esophageal varices during peristaltic contraction

Miller

Kim²,

Dai³

et al. 2004

American Journal of Physiology-Gastrointestinal and Liver Physi

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Our hypothesis states that variceal pressure and wall tension increase dramatically during esophageal peristaltic contractions. This increase in pressure and wall tension is a natural consequence of the anatomy and physiology of the esophagus and of the esophageal venous plexus. The purpose of this study was to evaluate variceal hemodynamics during peristaltic contraction. A simultaneous ultrasound probe and manometry catheter was placed in the distal esophagus in nine patients with esophageal varices. Simultaneous esophageal luminal pressure and ultrasound images of varices were recorded during peristaltic contraction. Maximum variceal cross-sectional area and esophageal luminal pressures at which the varix flattened, closed, and opened were measured. The esophageal lumen pressure equals the intravariceal pressure at variceal flattening due to force balance laws. The mean flattening pressures (40.11 Ϯ 16.77 mmHg) were significantly higher than the mean opening pressures (11.56 Ϯ 25.56 mmHg) (P Յ 0.0001). Flattening pressures Ͼ80 mmHg were generated during peristaltic contractions in 15.5% of the swallows. Variceal cross-sectional area increased a mean of 41% above baseline (range 7-89%, P Ͻ 0.0001) during swallowing. The peak closing pressures in patients that experience future variceal bleeding were significantly higher than the peak closing pressures in patients that did not experience variceal bleeding (P Ͻ 0.04). Patients with a mean peak closing pressure Ͼ61 mmHg were more likely to bleed. In this study, accuracy of predicting future variceal bleeding, based on these criteria, was 100%. Variceal models were developed, and it was demonstrated that during peristaltic contraction there was a significant increase in intravariceal pressure over baseline intravariceal pressure and that the peak intravariceal pressures were directly proportional to the resistance at the gastroesophageal junction. In conclusion, esophageal peristalsis in combination with high resistance to blood flow through the gastroesophageal junction leads to distension of the esophageal varices and an increase in intravariceal pressure and wall tension. esophageal varices; simultaneous ultrasound and manometry; variceal bleeding ESOPHAGEAL VARICEAL BLEEDING occurs when an expanding force within the varix exceeds the maximum wall tension. Wall tension is an inwardly directed force opposing an outwardly directed expanding force. Wall tension can be calculated by the Laplace equation. The Laplace equation (WT ϭ p v Ϫ p e ϫ r/w) states that the wall tension (WT) is equal to the transmural pressure difference (p v Ϫ p e ) (where p v is the intravariceal pressure and p e is the esophageal lumen pressure) times the radius of the varix (r) divided by the wall thickness (w). Thus this force is directly proportional to the transmural pressure difference and the radius of the varix and inversely proportional to the wall thickness of the varix.No methods are presently available that can measure variceal pressures during a peristaltic contraction of the e...

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“…Wall tension is directly proportional to variceal pressure and variceal radius, while inversely proportional to variceal wall thickness. Studies have demonstrated the accuracy of EUS in determining variceal radius and wall thickness, which can be helpful as a minimally‐invasive way of predicting intravariceal pressure . More invasive EUS methods involve needle puncture to determine intravariceal pressure .…”

Section: Eus and Esophageal Varicesmentioning

confidence: 99%

Endoscopic ultrasound and the liver: current applications and beyond

Shah

Baron

2018

J Hepato Biliary Pancreat

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The diagnosis and management of many gastrointestinal conditions has been augmented by the development of endoscopic ultrasound. Its role in the diagnosis and management of liver disease has been somewhat limited, but with the rapid development of therapeutic advancements it has quickly emerged as a useful tool in the management of complex hepatic conditions. This includes its use in the management of complications of portal hypertension as well as its use in liver lesions and cancer. In this paper, we review case studies, case series and trials for hepatic applications of endoscopic ultrasound to provide an overview of its utilization in this field and demonstrating its more novel applications for future use.

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Use of high-resolution endoluminal sonography to measure the radius and wall thickness of esophageal varices

Cited by 44 publications

References 9 publications

Ultrasound system to measure esophageal varix pressure: an in vitro validation study

Ultrasound system to measure esophageal varix pressure: an in vitro validation study

Mechanics and hemodynamics of esophageal varices during peristaltic contraction

Endoscopic ultrasound and the liver: current applications and beyond

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