Noninvasive endoscopic determination of intravariceal pressure in patients with portal hypertension: clinical experience with a new balloon technique

A Noninvasive Technology Using Artificial Intelligence to Measure the Diameter of Esophageal Varices Under Endoscopy

BACKGROUND

The diameter of esophageal varices (EVs) can not only predict variceal bleeding episodes but is also considered to be a significant factor in determining the endoscopic treatment of EVs. At present, visual observation is the most common method for estimating the diameter of EVs, the results of which may vary greatly between endoscopists.

MATERIALS AND METHODS

Herein, a noninvasive measurement technology, a virtual ruler (VR), was designed using artificial intelligence. The diameter and pressure of EVs in 7 patients were measured using VR and an esophageal varix manometer (EVM). Statistical methods, including the Bland-Altman Plot and Pearson correlation coefficient analysis, were used to compare the aforementioned 2 methods.

RESULTS

The results showed that the diameter of EVs measured using the aforementioned 2 methods did not differ. In addition, the time taken to measure the diameter of EVs using VR was 31 seconds (range, 25 to 44 s), significantly shorter compared with 159 seconds (range, 95 to 201 s) taken using an EVM ( P < 0.01). Furthermore, the diameter of EVs measured using an EVM exhibited a high linear correlation with pressure.

CONCLUSIONS

The current study demonstrated that VR was more accurate in measuring the diameter of EVs compared with EVMs while reducing unnecessary early intervention and the risk of complications. In terms of clinical risk and economic cost, this technology is hardly a burden. Overall, VR could be a useful software for the endoscopic detection and treatment of EVs in patients with liver cirrhosis.

Effect of intravariceal sclerotherapy combined with esophageal mucosal sclerotherapy using small-volume sclerosant for cirrhotic patients with high variceal pressure

AIM: To explore the effect of intravariceal-mucosal sclerotherapy using small dose of sclerosant on the recurrence of esophageal varices.

METHODS: We randomly assigned 38 cirrhotic patients with previous variceal bleeding and high variceal pressure (> 15.2 mmHg) to receive endoscopic variceal ligation (EVL) and combined intravariceal and esophageal mucosal sclerotherapy (combined group) using small-volume sclerosant. The end-points of the study were rebleeding and recurrence of esophageal varices.

RESULTS: During a median follow-up period of 16 mo, varices recurred in 1 patient in the combined group as compared with 7 patients in the EVL group (P = 0.045). Rebleeding occurred in 3 patients in the EVL group as compared with 1 patient in the combined group (P = 0.687). No patient died in the two groups. No significant differences were observed between the two groups with respect to serious adverse events.

CONCLUSION: Intravariceal-mucosal sclerotherapy using small dose of sclerosant is more effective than EVL in decreasing the incidence of variceal recurrence for cirrhotic patients.

Effects of propranolol or propranolol plus isosorbide-5-mononitrate on variceal pressure in schistosomiasis

AIM: To compare the effects of propranolol (PR) to that of PR plus isosorbide-5-mononitrate (ISMN) on variceal pressure in patients with schistosomiasis.

METHODS: Forty-eight patients with schistosomiasis who had no previous variceal bleeding were treated with PR alone or PR plus ISMN. Seven patients refused variceal pressure manometry (3 receiving PR and 4 receiving PR plus ISMN). One patient withdrew from the trial due to headache after taking ISMN. At the time of termination, twenty patients were randomly assigned to treatment with PR plus ISMN or PR alone. The dose of PR was adjusted until the resting heart rate had been reduced by 25% or was less than 55 bpm. In the PR plus ISMN group, after PR was titrated to the same target, the dose of ISMN was increased up to 20 mg orally twice a day. Variceal pressure was measured using a noninvasive endoscopic balloon technique at the end of the 6-mo treatment period.

RESULTS: In 40 patients (20 in the PR group and 20 in the PR plus ISMN group), variceal pressure was measured before treatment and at the end of the 6-mo treatment period. PR or PR plus ISMN treatment caused a significant reduction in variceal pressure (PR group: from 24.15 ± 6.05 mmHg to 22.68 ± 5.70 mmHg, P = 0.001; PR plus ISMN group: from 25.69 ± 5.26 mmHg to 20.48 ± 5.43 mmHg; P < 0.001). The percentage decrease in variceal pressure was significant after PR plus ISMN compared with that after PR alone (15.93% ± 8.37% vs 6.05% ± 3.67%, P = 0.01). One patient in the PR plus ISMN group and two patients in the PR group had variceal bleeding during follow-up. There were no significant differences between the two groups regarding the incidence of variceal bleeding. In the PR plus ISMN group, three patients had headache and hypotension. The headache was mild and transient and promptly disappeared after continuation of the relevant drug in two patients. Only one patient withdrew from the trial due to severe and lasting headache after taking ISMN. No side effects occurred in the PR group.

CONCLUSION: PR plus ISMN therapy may be an alternative treatment for patients with schistosomiasis who have a high risk of bleeding.

Esplenectomia e ligadura da veia gástrica esquerda na esquistossomose mansônica: efeitos sobre pressão das varizes do esôfago e indicadores endoscópicos de risco de sangramento por varizes esofagogástricas

RACIONAL: Expressivo contingente de pacientes esquistossomóticos com a forma hepatoesplênica e hipertensão portal apresentam hemorragia causada pela ruptura de varizes esofagogástricas, principal causa de alta morbidade e mortalidade da doença. OBJETIVO: Investigar os efeitos da esplenectomia e ligadura da veia gástrica esquerda sobre fatores de risco de sangramento por varizes esofagogástricas em portadores de esquistossomose mansônica, forma hepatoesplênica, com antecedente de hemorragia digestiva alta. MÉTODO: Estudaram-se, de forma prospectiva, 34 pacientes, com idade entre 1 e 74 anos (média 44,14), sendo 18 (53%) mulheres. Analisaram-se: 1) pressão das varizes do esôfago, aferida pela técnica endoscópica do balão pneumático; 2) tamanho, local, cor e sinais de cor vermelha nas varizes do esôfago; 3) varizes gástricas e gastropatia da hipertensão portal. Realizaram-se avaliações no pré-operatório, no pós-operatório imediato e no sexto mês após a ligadura da veia gástrica esquerda. RESULTADOS: A pressão das varizes do esôfago diminuiu de 22,3+/-2,6 mmHg, antes da operação, para 16,0+/-3,0 mmHg no pós-operatório imediato (p<0,001), caindo para 13,3+/-2,6 mmHg no pós-operatório do sexto mês (p<0,001). A proporção de varizes de grosso calibre, varizes no esôfago superior, varizes de cor azul, varizes com sinais de cor vermelha e de gastropatia da hipertensão portal decresceu de forma significante apenas no sexto mês de pós-operatório. CONCLUSÃO: A ligadura da veia gástrica esquerda, em esquistossomóticos hepatoesplênicos, com antecedente de hemorragia digestiva alta, revelou-se eficaz em diminuir alguns dos principais fatores de risco de hemorragia por varizes esofagogástricas, indicando boa perspectiva no controle definitivo do sangramento.

[Invasive diagnosis of portal hypertension in cirrhosis: a critical evaluation of the hepatic venous pressure gradient measurement]

Portal hypertension is defined by an increased pressure gradient between the portal vein and the inferior vena cava (N < 5 mmHg). The most commonly used technique to assess the severity of portal hypertension is the catheterization of one hepatic vein with measurement of pressures in a free position and in a wedged position using preferably a balloon catheter. The hepatic venous pressure gradient is calculated by the difference between both pressures. In most cirrhotic processes, venous pressure gradient gives a good evaluation of portal hypertension however, portal vein pressure can be higher than wedged hepatic venous pressure, particularly in presence of an increased pre-sinusoidal resistance. In such cases, a direct access to portal vein might be needed to assess the severity of portal hypertension. For an accurate interpretation of the hepatic venous pressure gradient, several strict criteria must be followed; otherwise the validity of measurements might be seriously questioned. Hepatic venous pressure gradient has been used as a prognostic marker of portal hypertension, particularly for the occurrence of bleeding from gastrophageal varices which almost never occur below a threshold value of 12 mmHg. However, the prognostic value of the hepatic venous pressure gradient for survival is still a controversial matter On the other hand, the use of hepatic venous pressure gradient has been proposed to monitor the pharmacological treatment of portal hypertension and it is generally accepted that reaching a same threshold value of 12 mmHg should almost completely abolish the risk of first or recurrent variceal bleeding. A large number of studies have also reported that a 20% hepatic venous pressure gradient decrease should be considered as a significant response to therapy, the risk of the first or recurrent bleeding being significantly reduced in responders. But again there are conflicting results.

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

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 +/- 0.7 mmHg) than the vein pressure. For a vein pressure of 25 mmHg, the average occlusion and opening pressures were 27 +/- 0.2 and 25.7 +/- 0.3 mmHg, respectively (P < .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.

Assessment of portal hypertension in humans

Patients suspected of having portal hypertension (either by clinical history, physical examination, or previous diagnosis) should undergo ultrasonography and upper gastrointestinal endoscopy. Ultrasonography, preferably using the duplex technique, can disclose the patency of the portal venous system, the presence of signs of portal hypertension (splenomegaly, portocollateral vessels, repermeabilization of the umbilical vein, and so forth) and provide additional information about liver, biliary, or pancreatic diseases that may be the cause of portal hypertension. Endoscopy can assess the presence and size of gastroesophageal varices, the appearance of the variceal wall, and the presence and severity of portal hypertensive gastropathy. Patients showing a patent portal vein should have hepatic vein catheterization to evaluate the presence of presinusoidal, sinusoidal, or postsinusoidal portal hypertension. Patients in whom presinusoidal portal hypertension is suspected (those having esophageal varices with an HVPG below 10 mm Hg) should have liver biopsy and percutaneous transhepatic measurement of portal pressure. In sinusoidal portal hypertension, the results of endoscopy and HVPG measurement are decisive for the therapeutic management of the patients. The authors' results indicate that, before starting prophylactic therapy with beta-blockers, all patients should undergo at least an hepatic vein catheterization to assess HVPG; it would be preferable to have a variceal pressure measurement also. These measurements must be repeated 3 to 4 weeks after the final dose of therapy has been reached to assess the risk of variceal bleeding or rebleeding.

Predictive value of the variceal pressure response to continued pharmacological therapy in patients with cirrhosis and portal hypertension

Noninvasive measurements of variceal pressure adequately reflect the hemodynamic effects of propranolol on portal hypertension. However, the prognostic value of variceal pressure responses during continued propranolol therapy has not been evaluated, and it is unclear whether this may substitute invasive measurements of portal pressure response. Fifty-five portal hypertensive patients with cirrhosis were studied before and at 4 months of continued propranolol therapy. Variceal pressure was measured using an endoscopic pressure gauge. Portal pressure was evaluated as the hepatic venous pressure gradient (HVPG). Over a 28 +/- 11 month follow-up, 16 patients experienced variceal bleeding. Baseline characteristics were similar in bleeders and nonbleeders. At 4 months, reduction in variceal pressure was less marked in bleeders than in nonbleeders (5% +/- 20% vs. -15% +/- 24%; P =.03). A fall in variceal pressure 20% or greater of baseline was an independent predictor of absence of variceal bleeding; which occurred in 5% of patients with a 20% or greater fall in variceal pressure versus 42% of patients with less than a 20% reduction (P =.004). The HVPG response had similar independent prognostic value (decrease > or =20%: 6% bleeding; decrease <20%: 45% bleeding; P =.004) but identified different patients. Achieving a 20% decrease in either variceal pressure or HVPG was highly sensitive (85%) and specific (93%) identifying patients not bleeding on follow-up. Endoscopic measurements of variceal pressure response to continued pharmacotherapy provide useful prognostic information on the risk of variceal bleeding. As with HVPG response, a fall in variceal pressure of 20% or greater is associated with a very low risk of variceal bleeding. The combination of both parameters allows almost optimal prognostication.