Local arterial vasoconstriction induced by octreotide in patients with cirrhosis

Intravenous metoclopramide for increasing endoscopic mucosal visualization in patients with acute upper gastrointestinal bleeding: a multicenter, randomized, double-blind, controlled trial

Acute upper gastrointestinal hemorrhage (UGIH) is the most common emergency condition that requires rapid endoscopic treatment. This study aimed to evaluate the effects of pre-endoscopic intravenous metoclopramide on endoscopic mucosal visualization (EMV) in patients with acute UGIH. This was a multicenter, randomized, double-blind controlled trial of participants diagnosed with acute UGIH. All participants underwent esophagogastroduodenoscopy within 24 h. Participants were assigned to either the metoclopramide or placebo group. Modified Avgerinos scores were evaluated during endoscopy. In total, 284 out of 300 patients completed the per-protocol procedure. The mean age was 62.8 ± 14.3 years, and 67.6% were men. Metoclopramide group achieved a higher total EMV and gastric body EMV score than the other group (7.34 ± 1.1 vs 6.94 ± 1.6; P = 0.017 and 1.80 ± 0.4 vs 1.64 ± 0.6; P = 0.006, respectively). Success in identifying lesions was not different between the groups (96.5% in metoclopramide and 93.6% in placebo group; P = 0.26). In the metoclopramide group, those with active variceal bleeding compared with the control group demonstrated substantial improvements in gastric EMV (1.83 ± 0.4 vs 1.28 ± 0.8, P = 0.004), antral EMV (1.96 ± 0.2 vs 1.56 ± 0.6, P = 0.003), and total EMV score (7.48 ± 1.1 vs 6.2 ± 2.3, P = 0.02). Pre-endoscopic intravenous metoclopramide improved the quality of EMV in variceal etiologies of UGIH, which was especially prominent in those who had signs of active bleeding based on nasogastric tube assessment.Trial Registration: Trial was registered in Clinical Trials: TCTR 20210708004 (08/07/2021).

Pathophysiology and Management of Variceal Bleeding

Cirrhosis is the fifth leading cause of death in adults. Advanced cirrhosis can cause significant portal hypertension (PH), which is responsible for many of the complications observed in patients with cirrhosis, such as varices. If portal pressure exceeds a certain threshold, the patient is at risk of developing life-threatening bleeding from varices. Variceal bleeding has a high incidence among patients with liver cirrhosis and carries a high risk of mortality and morbidity. The management of variceal bleeding is complex, often requiring a multidisciplinary approach involving pharmacological, endoscopic, and radiologic interventions. In terms of management, three stages can be considered: primary prophylaxis, active bleeding, and secondary prophylaxis. The main goal of primary and secondary prophylaxis is to prevent variceal bleeding. However, active variceal bleeding is a medical emergency that requires swift intervention to stop the bleeding and achieve durable hemostasis. We describe the pathophysiology of cirrhosis and PH to contextualize the formation of gastric and esophageal varices. We also discuss the currently available treatments and compare how they fare in each stage of clinical management, with a special focus on drugs that can prevent bleeding or assist in achieving hemostasis.

Peptide-based therapy in portal hypertension

PURPOSE OF REVIEW

To summarize the use of gastrointestinal peptides in the management of portal hypertension.

RECENT FINDINGS

Vasoactive peptides are commonly used in the management of acute variceal hemorrhage and hepatorenal syndrome, which are portal hypertensive complications of cirrhosis. The main vasoactive peptides that are used are somatostatin and its long-acting analogue octreotide, and vasopressin and its analogue terlipressin. Early initiation of vasoactive peptides in the management of acute variceal hemorrhage and hepatorenal syndrome is associated with improved outcomes. Octreotide is the available vasoactive peptide in the Unites States. Recent developments and ongoing clinical trials may improve our understanding of hepatorenal syndrome and influence the use of vasoactive peptides, particularly terlipressin.

SUMMARY

Here, we review the literature on the use of vasoactive peptides in the management of acute variceal hemorrhage and hepatorenal syndrome.

Somatostatin and the "Small-For-Size" Liver

“Small-for-size” livers arising in the context of liver resection and transplantation are vulnerable to the effects of increased portal flow in the immediate postoperative period. Increased portal flow is an essential stimulus for liver regeneration. If the rise in flow and stimulus for regeneration are excessive; however, liver failure and patient death may result. Somatostatin is an endogenous peptide hormone that may be administered exogenously to not only reduce portal blood flow but also offer direct protection to different cells in the liver. In this review article, we describe key changes that transpire in the liver following a relative size reduction occurring in the context of resection and transplantation and the largely beneficial effects that peri-operative somatostatin therapy may help achieve in this setting.

Case report on intravenous octreotide for the treatment of intraoperative vasoplegia following thymoma resection

Octreotide is a somatostatin analog known for its role in the treatment of acute variceal bleeding, enterocutaneous fistula and carcinoid syndrome. The reduction of portal pressure from splanchnic vasoconstriction has been attributed to the inhibition of nitric oxide synthesis, guanylate cyclase and release of glucagon. Octreotide has many therapeutic applications as a result of the ubiquitous nature of somatostatin receptors throughout the body. The effects of octreotide on vascular tone make it potentially useful in the treatment of intraoperative vasoplegia, hypotension with low systemic vascular resistance with preserved cardiac output that is refractory to adrenergic agonists. We present a case in which a patient undergoing thymoma resection developed vasoplegia that was effectively treated with octreotide. We believe that this case illustrates the need for further investigation on the potential efficacy of octreotide as an adjunct for the treatment of vasoplegia and other forms of shock.

Effects of a Long-Acting Formulation of Octreotide on Patients with Portal Hypertension

Objective

This study aimed to determine whether the treatment of a long-acting formulation of octreotide (OCT-LAR) exerted a similar effect on improving the prognosis of patients with portal hypertension compared with placement of transjugular intrahepatic portosystemic shunts (TIPSs).

Methods

A total of 24 patients with portal hypertension who underwent TIPS placement or OCT-LAR treatment from January 2010 to January 2015 were reviewed. Hemodynamic studies, biological values, live functions, and treatment complications before and during the treatment were evaluated.

Results

Baseline clinical characteristics were similar between two groups. Hepatic venous pressure gradient (HVPG) was improved in OCT-LAR groups (15.9 ± 2.4 to 12.8 ± 1.6 mmHg). Both groups showed a slight decrease in endothelin-1 (ET-1) and urotensin II and a slight increase in oxide metabolite (NOx) concentrations with no significant difference. Aspartate aminotransferase and alanine aminotransferase increased one week after TIPS placement when they improved in the OCT-LAR treatment group. The complications of OCT-LAR treatment were minor and transient. However, one patient who received TIPS placement presented procedure-related complications and required rehospitalization, and 2 patients had developed hepatic encephalopathy during the follow-up period.

Conclusion

Prolonged administration of OCT-LAR exerted a virtually similar effect on improving hemodynamic parameters and liver function in patients with portal hypertension compared with placement of TIPS, with no apparent serious adverse effects.

Size mismatch in liver transplantation

Size mismatch is an unique and inevitable but critical issue in live donor liver transplantation. Unmatched metabolic demand of recipient as well as physiologic mismatch aggravates the damage to liver graft, inevitably leading to graft failure on recipient. Also, an excessive resection of liver graft for better recipient outcome in live donor liver transplant may jeopardize the healthy donor well-being and even put donor life in danger. There is a fine balance between resected graft volume required to meet the recipient's metabolic demand and residual graft volume required for donor safety. The obvious clinical necessity of finding that balance has prompted a clinical need and promoted the improvement of knowledge and development of management strategies for size-mismatched transplants. The development of the size-matching methodology has significantly improved graft outcome and recipient survival in live donor liver transplants. On the other hand, the effect of size mismatch in cadaveric transplants has never been observed as being so pronounced. The importance of matching of the donor recipient size has been unrecognized in cadaveric liver transplant. In this review, we attempt to summarize the current most updated knowledge on the subject, particularly addressing the definition and complications of size-mismatched cadaveric liver transplant, as well as management strategies.

Association between a polymorphic poly-T repeat sequence in the promoter of the somatostatin gene and hypertension

Despite the numerous common pathways connecting blood pressure regulation to somatostatin (SST) metabolism, the SST gene has never been seen as a significant blood pressure modulator. The aim of this study was to evaluate the association between a poly-T repeat sequence (rs34872250) in the promoter of the SST gene and blood pressure, according to the obesity status. We genotyped 1918 French-Canadian subjects from a founder population. Analyses were performed according to the length of the poly-T repeat sequence on both alleles and divided into two groups, the 13/13-13/14 group and the 13/15-13/16 group. The effect of age, gender, body mass index, antihypertensive drugs and diabetic status were considered. Systolic, diastolic and mean blood pressures are significantly higher among the 13/15-13/16 group in the whole sample (P<0.05). Whereas the differences remain significant in women, they turn to be non-significant when men are considered alone. The risk of hypertension is increased in the 13/15-13/16 group, particularly among overweight/obese subjects. Systolic blood pressure is significantly higher among overweight/obese carriers of the 13/15-13/16 alleles in the whole sample (P<0.001), in men (P=0.006) and in women (P=0.002), even after correction for age and antihypertensive drugs. These results suggest that the poly-T repeat sequence polymorphism in the promoter of the SST gene is associated with significant variations of blood pressure and could modulate the risk of hypertension, particularly among women.

Somatostatin therapy protects porcine livers in small-for-size liver transplantation

Small-for-size (SFS) injury occurs in partial liver transplantation due to several factors, including excessive portal inflow and insufficient intragraft responses. We aim to determine the role somatostatin plays in reducing portal hyperperfusion and preventing the cascade of deleterious events produced in small grafts. A porcine model of 20% liver transplantation is performed. Perioperatively treated recipients receive somatostatin and untreated controls standard intravenous fluids. Recipients are followed for up to 5 days. In vitro studies are also performed to determine direct protective effects of somatostatin on hepatic stellate cells (HSC) and sinusoidal endothelial cells (SEC). At reperfusion, portal vein flow (PVF) per gram of tissue increased fourfold in untreated animals versus approximately threefold among treated recipients (p = 0.033). Postoperatively, markers of hepatocellular, SEC and HSC injury were improved among treated animals. Hepatic regeneration occurred in a slower but more orderly fashion among treated grafts; functional recovery was also significantly better. In vitro studies revealed that somatostatin directly reduces HSC activation, though no direct effect on SEC was found. In SFS transplantation, somatostatin reduces PVF and protects SEC in the critical postreperfusion period. Somatostatin also exerts a direct cytoprotective effect on HSC, independent of changes in PVF.

Meta-analysis: vasoactive medications for the management of acute variceal bleeds

BACKGROUND

Vasoactive medications such as vasopressin, somatostatin and their analogues (terlipressin, vapreotide and octreotide) are commonly used for the treatment of acute variceal bleeding. However, the risks and benefits of these interventions are not well understood.

AIM

To undertake a meta-analysis of the efficacy of vasoactive medications in patients having acute variceal bleeds.

METHODS

Randomised controlled trials (RCTs) of vasopressin, somatostatin and their analogues, administered to patients with acute variceal bleeds were identified based on systematic searches of nine electronic databases and multiple sources of grey literature.

RESULTS

The search identified 3011 citations, and 30 trials with a total of 3111 patients met eligibility criteria. The use of vasoactive agents was associated with a significantly lower risk of 7-day mortality (RR 0.74; 95% CI 0.57-0.95; P = 0.02; I(2) = 0%; moderate quality of evidence), and a significant improvement in haemostasis (RR 1.21, 95% CI 1.13-1.30; P < 0.001; I(2) = 28%; very low quality of evidence), lower transfusion requirements (pooled mean difference -0.70 units of blood transfused, 95% CI -1.01 to -0.38; P < 0.001; I(2) = 82%; moderate quality of evidence), and a shorter duration of hospitalisation (pooled mean difference -0.71 days; 95% CI -1.23 to -0.19; P = 0.007; I(2) = 0%; low quality of evidence). Studies comparing different vasoactive agents did not show a difference in efficacy, although the quality of evidence was very low.

CONCLUSIONS

The use of vasoactive agents was associated with a significantly lower risk of acute all-cause mortality and transfusion requirements, and improved control of bleeding and shorter hospital stay. Studies comparing different vasoactive medications failed to demonstrate a difference in efficacy.

[Octreotide treatment for postoperative chylous ascites in an adult]

Chylous ascites is infequent after abdominal surgery. We describe the case of a 43-year-old man with portal cavernomatosis who underwent surgery to insert a splenorenal shunt, which was not placed due to the absence of signs of portal hypertension. On postoperative day 20, the patient developed abdominal distension and mild dyspnea and was diagnosed with chylous ascites, which was related to the surgery. The patient was initially treated with diet and diuretics, with no clinical response, and consequently octreotide therapy was started. Four days later, the ascites was almost resolved and an ultrasound scan at 4 months showed its complete disappearance. This article demonstrates the effectiveness of octreotide in the treatment of postsurgical chylous ascites.

Randomised clinical trial: the safety and efficacy of long-acting octreotide in patients with portal hypertension

BACKGROUND

It remains unclear whether a long-acting preparation of octreotide (Sandostatin LAR) can be safely used for portal hypertension in patients with compensated cirrhosis.

AIM

To determine the safety and efficacy of LAR among patients with Child Pugh Class A or B cirrhosis and small oesophageal varices.

METHODS

A randomised, double-blind, placebo-controlled study was conducted in 39 patients with cirrhosis and small oesophageal varices. Safety was based on frequency and severity of adverse events. Efficacy was determined by hepatic vein pressure gradient (HVPG) measured at baseline and day 84 following administration of LAR 10 mg (n = 15), 30 mg (n = 10) or saline (n = 14). Fasting and postprandial portal blood flow (PBF), superior mesenteric artery pulsatility index (SMA-PI), glucagon and octreotide levels were measured. An intention-to-treat analysis was performed.

RESULTS

Four patients in the LAR 30 group (40%) withdrew from the study due to serious adverse events. No patient in the LAR 10 or control group had serious adverse events. There was no statistically significant decrease between HVPG at day 84 and baseline with LAR 30 mg (11.8 ± 2.3 mmHg vs. 14.1 ± 3.2), LAR 10 mg (15.3 ± 4.8 mmHg vs. 15.1 ± 3.8), or saline (13.3 ± 3.8 mmHg vs. 15.1 ± 4.3) (P = 0.26). Neither PBF, SMA-PI nor plasma glucagon levels were significantly decreased from baseline (P = 0.56).

CONCLUSIONS

The absence of significant haemodynamic benefit, as well as the high frequency of severe adverse events associated with use of LAR, do not support the use of this agent in the treatment of portal hypertension.

Hepatorenal syndrome: do the vasoconstrictors work?

The development of hepatorenal syndrome (HRS) is related to many changes associated with advanced cirrhosis. Because vasoconstrictors correct systemic and splanchnic hemodynamic abnormalities, they are effective treatments for HRS, although only in approximately 40% of HRS patients. Emerging data show that combination treatment with vasoconstrictors and TIPS may yield better outcomes than either alone. All HRS patients should be assessed for liver transplantation. Reversing HRS before transplantation is associated with better long-term survival. Combined liver– kidney transplantation is indicated for those with irreversible kidney injury. Otherwise, there is some merit in performing a liver transplant first and only considering a kidney transplant later.

Necrotizing enterocolitis in neonates receiving octreotide for the management of congenital hyperinsulinism

The somatostatin analog octreotide was used for the first time in the treatment of an infant with congenital hyperinsulinism in 1986. Since then, it is commonly used in the management of congenital hyperinsulinemic hypoglycemias. Despite a wide variety of potential adverse reactions, octreotide is generally well tolerated. It has been extensively demonstrated that octreotide reduces the splanchnic blood flow in a dose-dependent manner, affecting the entire gastrointestinal tract, and some concern has been recently raised regarding the potential implications of this effect in the development of necrotizing enterocolitis in neonates receiving octreotide for the management of congenital hyperinsulinism. The aim of this report is to present a series of patients treated at our institution in which we observed this association, and review the current related literature.

Resolution of hepatic encephalopathy following hepatic artery embolization in a patient with well-differentiated neuroendocrine tumor metastatic to the liver

Hepatic encephalopathy is considered a contraindication to hepatic artery embolization. We describe a patient with a well-differentiated neuroendocrine tumor metastatic to the liver with refractory hepatic encephalopathy and normal liver function tests. The encephalopathy was refractory to standard medical therapy with lactulose. The patient's mental status returned to baseline after three hepatic artery embolization procedures. Arteriography and ultrasound imaging before and after embolization suggest that the encephalopathy was due to arterioportal shunting causing hepatofugal portal venous flow and portosystemic shunting. In patients with a primary or metastatic well-differentiated neuroendocrine tumor whose refractory hepatic encephalopathy is due to portosystemic shunting (rather than global hepatic dysfunction secondary to tumor burden), hepatic artery embolization can be performed safely and effectively.

Gastrointestinal bleeding in the elderly. ACTA ACUST UNITED AC. 2008;5:80-93. [PMID: 18253137 DOI: 10.1038/ncpgasthep1034]

Gastrointestinal bleeding affects a substantial number of elderly people and is a frequent indication for hospitalization. Bleeding can originate from either the upper or lower gastrointestinal tract, and patients with gastrointestinal bleeding present with a range of symptoms. In the elderly, the nature, severity, and outcome of bleeding are influenced by the presence of medical comorbidities and the use of antiplatelet medication. This Review discusses trends in the epidemiology and outcome of gastrointestinal bleeding in elderly patients. Specific causes of upper and lower gastrointestinal bleeding are discussed, and recommendations for approaches to endoscopic diagnosis and therapy are given.

Octreotide enhances portal pressure reduction induced by propranolol in cirrhosis: a randomized, controlled trial

BACKGROUND

In vitro, octreotide potentiates vasoconstriction in isolated, preconstricted, mesenteric arterial vessels. In cirrhotic patients, portal pressure (HVPG) reduction induced by propranolol is partly due to splanchnic vasoconstriction.

AIM

To evaluate HVPG effects of octreotide administration in cirrhotic patients receiving long-term propranolol.

PATIENTS AND METHODS

A randomized, controlled trial. First study: a total of 28 patients were studied at baseline and 30 and 60 minutes after octreotide (200 mug) (N = 14) or placebo (N = 14) and then treated with propranolol for approximately 30 days (106 +/- 5 mg/day). Second study: after baseline evaluation patients received octreotide or placebo as they were assigned to in the first study and measurements repeated 30 and 60 minutes later.

RESULTS

In the first study baseline HVPG was 18.7 +/- 0.9 mmHg and decreased to 17.1 +/- 1.1 mmHg and 17.1 +/- 1.0 mmHg (both P < 0.05 vs baseline) at 30 and 60 minutes after octreotide, respectively. Eight patients decreased their HVPG after octreotide. In the second study baseline HVPG was 15.6 +/- 1.3 mmHg (P < 0.01 vs baseline HVPG in first study) and decreased to 14.1 +/- 1.2 mmHg and 14.1 +/- 1.3 mmHg (25.7 +/- 5% lower than baseline HVPG in the first study, P < 0.01) (both P < 0.05 vs baseline) at 30 and 60 minutes after octreotide, respectively. Nine patients (2 responders/7 nonresponders to propranolol) decreased their HVPG after octreotide. Octreotide effects may be mediated by potentiation and additive mechanisms.

CONCLUSIONS

Octreotide enhances HVPG reduction induced by propranolol in cirrhotic patients.

The effects of treatment with octreotide, diuretics, or both on portal hemodynamics in nonazotemic cirrhotic patients with ascites

GOALS

To evaluate the effects of diuretic treatment, octreotide, or both on portal hemodynamics in nonazotemic cirrhotic patients with ascites.

BACKGROUND

Diuretics and octreotide have been associated with a decrease in portal pressure in cirrhotic patients, suggested to be mediated by plasma volume depletion and splanchnic vasoconstriction, respectively. However, liver cirrhosis is characterized by activation of the renin-angiotensin-aldosterone axis, which increases hepatic vascular resistance and is augmented or suppressed by diuretics or octreotide, respectively.

STUDY

Twenty nonazotemic cirrhotic patients with ascites were treated with furosemide and spironolactone. Of them, 10 (group 1) discontinued diuretic treatment for 7 days. Thereafter for 5 days, each patient received subcutaneous octreotide, 300 microg twice per day; ten of them (group 2) received the octreotide in addition to their usual diuretic treatment. Portal and systemic hemodynamics with Doppler ultrasound and endogenous vasoactive systems were evaluated while the patients received diuretics (both groups), after discontinuation of diuretics (group 1), and after octreotide administration (both groups).

RESULTS

The withdrawal of diuretics did not alter portal hemodynamics, but it impaired systemic hemodynamics and suppressed the renin-aldosterone axis. The addition of octreotide to diuretic treatment but not octreotide alone improved portal and systemic hemodynamics. In both groups the initiation of octreotide administration suppressed the renin-aldosterone axis and plasma glucagon levels.

CONCLUSIONS

In nonazotemic cirrhotic patients with ascites, the combination of diuretics and octreotide improves systemic hemodynamics and inhibits the diuretic-related component of the activated renin-aldosterone axis, which in turn augments the portal hypotensive effect of diuretic-induced plasma volume depletion.

Chylous ascites following operation for para-aortic lymph node dissection in a patient with cervical cancer

This is a case report of chylous ascites caused by performing para-aortic lymph node dissection for a patient with cervical cancer. Postoperative chylous ascites is a rare condition that usually develops as a result of operative trauma to the thoracic duct, cisterna chyli, or their major tributaries. It has mainly occurred in thoracic operations, and chylous ascites has rarely been reported in gynecologic surgery. It is associated with serious nutritional and immunologic consequences due to the constant loss of protein and lymphocytes. Treatment that comprises conservative and surgical procedures is selected based on disease severity. We experienced massive chylous ascites after para-aortic surgery and successfully managed it conservatively with dietary intervention and parenteral nutrition.

Octreotide in liver cirrhosis: a salvage for variceal bleeding can be a gunshot for kidneys

BACKGROUND

The renal effects of octreotide, used for bleeding esophageal varices in cirrhosis, are controversial.

METHODS

Fourteen cirrhotic patients (Child-Pugh; A/B/C: 1/12/1) were enrolled. Plasma nitrite and endothelin (ET) levels, urinary nitrite output, free water clearance (FWC) and fractional excretion of filtered sodium (FENa) were measured and renal Doppler ultrasound was carried out. Octreotide was infused at a rate of 0.75 microg/kg/h for 3 h after a bolus of 0.75 microg/kg body weight. All the parameters were reevaluated during octreotide administration while the patients acted as their own controls.

RESULTS

Octreotide induced significant reductions in urinary nitrite, FENa and FWC. Plasma ET levels increased (baseline: 6.7 pg/ml, octreotide: 8.4 pg/ml), whereas the plasma nitrite level did not change significantly after octreotide infusion. Overall, no significant change in renal resistive index (RRI) could be demonstrated on Doppler after octreotide administration. However, patients with elevated baseline RRI values had significantly more deterioration in FWC and FENa compared with patients with normal RRI in response to octreotide.

CONCLUSION

A marked decrease in FENa, FWC and urinary nitrite output, together with a significant increase in plasma ET level in response to octreotide, may indicate renal dysfunction in cirrhotic patients. This deleterious renal effect of octreotide may be more enhanced in patients with elevated baseline RRI.

Hemodynamic effects of terlipressin and high somatostatin dose during acute variceal bleeding in nonresponders to the usual somatostatin dose

OBJECTIVES

High dose of somatostatin infusion achieves a greater reduction of hepatic venous pressure gradient (HVPG) than the usual dose, and terlipressin decreases HVPG through mechanisms other than somatostatin. Our aim was to assess the hemodynamic effects of terlipressin and high somatostatin dose during acute variceal bleeding in nonresponders to the usual somatostatin dose.

METHODS

Hemodynamic studies were performed in 80 patients with cirrhosis and variceal bleeding during the first 3 days of admission. After baseline measurements, somatostatin was administered (250 microg/h with an initial bolus of 250 microg). Patients were considered responders when the HVPG decreased by >10% from baseline (n = 31). Nonresponders were randomized under double-blind conditions to a control group (n = 7), or to receive terlipressin (2 mg IV bolus, n = 22), or high dose of somatostatin (500 microg/h, n = 20). Final measurements were obtained 30 min later.

RESULTS

Terlipressin caused a decrease in HVPG (from 22.2 +/- 5 to 19.1 +/- 5.2, p < 0.01) and heart rate (p < 0.01), while mean arterial pressure increased (p < 0.01). High somatostatin dose also reduced HVPG (from 21.8 +/- 3.4 to 19.6 +/- 3.1, p < 0.01), although this decrease was more pronounced with terlipressin (15%+/- 9%vs 10%+/- 6% from baseline, p= 0.05). Both terlipressin and high somatostatin dose achieved a significantly higher rate of response than that in the control group. A decrease in HVPG >20% was observed in 36% of cases with terlipressin versus 5% with high somatostatin dose (p= 0.02).

CONCLUSIONS

In nonresponders to usual somatostatin dose, both terlipressin and high-dose of somatostatin infusion significantly decreased HVPG and increased the rate of hemodynamic responders. Such effects were greater with terlipressin. Both treatments may be an alternative when standard somatostatin fails.

Acute hemodynamic effects of octreotide and terlipressin in patients with cirrhosis: a randomized comparison

BACKGROUND

Octreotide and terlipressin are widely used in acute variceal hemorrhage to reduce the bleeding rate. They purportedly act by mesenteric arterial vasoconstriction, thus reducing portal venous flow (PVF) and portal pressure. Little is known about the immediate-early hemodynamic effects of these drugs.

AIM

To compare the acute hemodynamic effects of octreotide and terlipressin in patients with cirrhosis.

PATIENTS

Forty-two cirrhotic patients with a history of variceal bleeding were randomized to receive either octreotide 100 microg intravenous bolus followed by a continuous infusion at 250 microg/h (n = 21), or terlipressin 2 mg intravenous bolus (n = 21).

METHODS

Mean arterial pressure (MAP), heart rate (HR), hepatic venous pressure gradient (HVPG), and PVF, assessed by duplex Doppler ultrasonography, were measured before and at 1, 5, 10, 15, 20, and 25 min after the start of drug administration.

RESULTS

Octreotide markedly decreased HVPG (-44.5 +/- 17.8%) and PVF (-30.6 +/- 13.6%) compared to the baseline at 1 min (p < 0.05). Thereafter, both variables rapidly returned toward the baseline, and by 5 min, no significant differences in HVPG (-7.1 +/- 28.9%) and PVF (10.2 +/- 26.2%) were noted. A similar transient effect on MAP and HR was observed. Terlipressin significantly decreased HVPG (-18.3 +/- 11.9%) and PVF (-32.6 +/- 10.5%) at 1 min (p < 0.05) and sustained these effects at all time points. The effects on arterial pressure and HR were also sustained.

CONCLUSIONS

Octreotide only transiently reduced portal pressure and flow, whereas the effects of terlipressin were sustained. These results suggest that terlipressin may have more sustained hemodynamic effects in patients with bleeding varices.

Estrogens and Neuropeptides in Raynaud's Phenomenon

Raynaud's phenomenon (RP) is characterized by ischemia and reperfusion of the extremities. Vasomotor instability is due to a microcirculatory disturbance that may be linked to different events involving the endothelium or peripheral nerve terminals. Endothelium and nerve endings "sense" the modifications of the microenvironment and both of them release factors that contribute to find a balance between vasolidation and vasoconstriction. Moreover, estrogens may contribute to control vascular tone regulating finger skin circulation. A loss of neuropeptides has been shown in secondary RP where supplementation with factors derived from nerve endings has been demonstrated to induce a potent vasolidation. Estrogen administration improved endothelial dysfunction in secondary RP. Neuropeptides and estrogens thus share the endothelial-dependent pathway, usually mediated by nitric oxide, in inducing vasolidation. The network directed by the endothelium is in reality controlled by a neuro-hormonal axis composed by neuropeptides and estrogens. This delicate balance keeps the vascular tone, and its dysfunction may lead to a dysregulation of vascular tone, manifest in clinics as a primary or secondary RP.

Effect of somatostatin versus octreotide on portal haemodynamics in patients with cirrhosis and portal hypertension

OBJECTIVES

Elevated portal inflow is part of the pathogenesis of portal hypertension in patients with cirrhosis. Vasoactive substances appear to play a primary role in the regulation of portal flow. The aim of this study was to investigate the effects of somatostatin and octreotide on portal pressure and plasma levels of insulin-like growth factor (IGF-1), nitric oxide (NO), endothelin-1 (ET-1) and glucagon (GLU).

METHODS

Portal pressures of 14 cirrhotic patients with portal hypertension who underwent transjugular intrahepatic portosystemic shunt (TIPS) were directly measured via a catheter placed in the portal vein. Portal pressure and IGF-1, NO, ET-1 and GLU plasma levels were determined at baseline, and at 8 h and 24 h after administration of somatostatin or octreotide via portal vein catheter in a randomized, double-blind, cross-over design.

RESULTS

The average decrease in portal pressure after intravenous infusion of somatostatin and octreotide was 9.4 +/- 1.0 cmH2O and 5.0 +/- 1.0 cmH2O, respectively (P < 0.01). Plasma levels of GLU and IGF-1 decreased significantly 8 and 24 h after somatostatin and octreotide infusion (P < 0.05). However, there were no significant decreases in plasma NO or ET-1 levels. There was a significant difference between somatostatin and octreotide groups (P < 0.01).

CONCLUSION

Both somatostatin and octreotide can significantly reduce portal pressure, although somatostatin is more potent than octreotide. The underlying mechanisms may involve inhibition of the secretion of GLU, IGF-1 and other hormones as well as a decrease in hepatic metabolism and portal inflow leading to a reduction in portal pressure.

Chylous ascites caused by portal vein thrombosis treated with octreotide

Chylous ascites is an uncommon entity with variable causes and rarely arises from portal vein thrombosis. This is a case report of chylous ascites caused by idiopathic portal vein thrombosis that was refractory to medical therapy and shunt surgery, which showed an impressive response to treatment with subcutaneous octreotide. We review the literature on chylous ascites with particular reference to the role of somatostatin analogs in the management of this rare condition.

Arterialization of the portal vein improves hepatic microcirculation and tissue oxygenation in experimental cirrhosis

Background

Arterialization of the portal vein (APV) has shown beneficial effects on liver regeneration and function in selected patients undergoing liver resection and transplantation. Whether APV improves liver perfusion and function in cirrhosis is unclear. This study investigated the effect of APV on hepatic haemodynamics and liver function in a rat model of cirrhosis.

Methods

Male Sprague–Dawley rats (250–300 g) were divided into three groups: normal controls (n = 7), cirrhosis with sham laparotomy (sham; n = 7) and cirrhosis with APV (APV; n = 9). Portal venous blood flow, portal vein pressure and hepatic parenchymal microcirculation (HPM) were measured before and after APV. Hepatic parenchymal oxygenation was assessed by near-infrared spectroscopy and hepatocellular injury by standard liver function tests. Measurements were taken at baseline, after APV and 7 days after surgery.

Results

APV increased portal blood flow and pressure in cirrhotic rats without altering intrahepatic portal resistance. APV increased the HPM in cirrhotic rats by a mean(s.e.m.) of 28·5(0·1) per cent on day 0 and 54·6(0·1) per cent by day 7 (P = 0·001). Liver tissue oxygenation was increased by APV and the plasma γ-glutamyltranspeptidase level was reduced (mean(s.e.m.) 6·0(0·5) versus 3·8(0·3) units/l before and after APV respectively; P = 0·006) at day 7.

Conclusion

APV increases portal blood flow, tissue perfusion and oxygenation in cirrhosis.

Pharmacological rationale for the use of somatostatin and analogues in portal hypertension

Somatostatin and its analogue octreotide have been used for two decades to treat oesophageal variceal haemorrhage. The drug was introduced because of its capacity to decrease portal venous pressure without major side effects. In clinical trials assessing the efficacy of somatostatin and long-acting analogues in arresting variceal haemorrhage, conflicting results have been obtained. Furthermore, in haemodynamic studies evaluating the effects of somatostatin and analogues in patients with cirrhosis, divergent effects were observed. The main reason for these differences is probably related to different affinities of the drugs for different somatostatin receptor subtypes. The effects of somatostatin and analogues are mediated via five different G-protein coupled receptors (somatostatin receptor subtypes 1-5), which regulate the activity of ion channels (Ca2+, K+, Na+ and Cl-) and enzymes (adenyl cyclase, phospholipase C, phospholipase A2, phosphoinositide 3-kinase and guanylate cyclase) responsible for the synthesis or degradation of intracellular second messengers including cyclic AMP, inositol 1,4,5-trisphosphate, diacylglycerol and cyclic GMP. Despite universal use of somatostatin, the cellular and biochemical mechanisms of its effects in portal hypertension are relatively poorly studied and remain incompletely understood. In this review, we summarize relevant signal transduction of somatostatin and analogues, the haemodynamic effects of the drugs and the possible mechanisms by which these effects are mediated.

Octreotide in hepatorenal syndrome: a randomized, double-blind, placebo-controlled, crossover study

The hepatorenal syndrome (HRS) is related to vasoconstriction of the renal cortex induced by systemic hypovolemia that follows splanchnic vasodilatation as the primary event in the cascade of hemodynamic changes associated with portal hypertension. We evaluated the effects of octreotide, a splanchnic vasoconstrictor, on HRS in cirrhotic patients. We compared the effects of octreotide infusion (50 microg/h) to placebo using a randomized, double-blind, cross-over design over 2, 4-day periods. Nineteen patients were included, and 14 patients could complete the 2 phases of the study (group 1: placebo first; n = 8 and group 2: octreotide first; n = 6) The end point of the study was to evaluate improvement in renal function as defined by a 20% decrease in serum creatinine value after a 4-day treatment as compared with baseline. In all the patients, a normal central venous pressure was maintained by daily intravenous administration of 2 units of albumin. The 2 groups were similar with regard to demographic data and liver and kidney function parameters at baseline. Improvement in renal function was observed in 2 patients after the placebo and 1 patient after octreotide infusion in group 1 and in 2 patients after octreotide infusion and 1 patient after placebo in group 2 (P = not significant). In addition, treatment with octreotide infusion did not result in significant changes in creatinine clearance, daily urinary sodium, plasma renin activity, plasma aldosterone and glucagon levels, or renal and mesenteric artery resistance indices as measured by Doppler ultrasonography. In conclusion, the present study demonstrates that, under our experimental conditions, octreotide infusion combined with albumin is not effective for the treatment of HRS in cirrhotic patients.

Current pharmacotherapy in the management of cirrhosis: focus on the hyperdynamic circulation

Many major complications of hepatic cirrhosis relate to the development of a characteristic hyperdynamic circulatory state in these patients, irrespective of the underlying disease aetiology. Vasodilatation of the systemic and splanchnic circulations leads to a reduced total systemic vascular resistance, increased cardiac output and intense activation of neurohumoral vasoconstrictor systems including the sympathetic nervous system, renin-angiotensin system and vasopressin. Vasoconstriction of the renal and hepatic circulations contributes to the development of renal failure and portal hypertension, respectively. Current treatments that focus on amelioration of these circulatory derangements offer much promise, however, they are often limited by side effects in these patients.

Renal hemodynamic effects of somatostatin are not related to inhibition of endogenous insulin release

BACKGROUND

Somatostatin inhibits endocrine and exocrine secretions and exerts renal vasoconstriction. The mechanism underlying somatostatin's vascular effects is unknown. Since insulin can cause vasodilation, we hypothesized that removal of basal insulin release by somatostatin may contribute to somatostatin-induced renal vasoconstriction.

METHODS

The study was conducted in different protocols comprising forty-six healthy male volunteers. Randomized studies were performed to compare the effects of somatostatin alone (0.1 microg/kg/min) to the effects of somatostatin + low dose insulin (0.1 mU/kg/min), the effects of somatostatin + low dose insulin to the effects of somatostatin + high dose insulin (1.5 mU/kg/min), and the effects of insulin (1.5 mU/kg/min) + somatostatin. Renal plasma flow (RPF) and glomerular filtration rate (GFR) were measured with the para-aminohippurate (PAH) and the inulin clearance technique, respectively. Blood pressure and pulse rate were measured non-invasively.

RESULTS

Somatostatin alone decreased GFR (-14 +/- 6%, P < 0.001) and RPF (-16 +/- 7%, P < 0.001) whereas systemic hemodynamics were unchanged. Preceding or concomitant infusion of insulin at high doses (insulin plasma concentration of 127 +/- 25 or 144 +/- 17 microU/mL) but not co-infusion with low dose insulin (insulin plasma concentration of 11 +/- 3 microU/mL) mitigated or reversed the vasoconstrictive actions of somatostatin on GFR and RPF.

CONCLUSIONS

Somatostatin induces marked renal vasoconstriction and exogenous restoration of fasting insulin concentrations does not influence the renal vascular effects. Therefore, it is unlikely that somatostatin-induced vasoconstriction is due to removal of basal insulin. Plasma insulin concentrations in the high postprandial range can reverse somatostatin-induced renal vasoconstriction, suggesting functional antagonism.

Effects of long-term propranolol and octreotide on postprandial hemodynamics in cirrhosis: a randomized, controlled trial

BACKGROUND & AIMS

Postprandial increases in portal pressure may influence esophageal variceal rupture. The effects of chronic propranolol and octreotide (100 and 200 microg subcutaneously in a single dose) on postprandial hemodynamics were evaluated.

METHODS

FIRST STUDY: 36 cirrhotic patients were studied at baseline and 30 and 60 minutes after a standard meal and then treated with propranolol (139 +/- 9 mg/d during 39 +/- 2 days). SECOND STUDY: After baseline measurements, patients were randomized into 3 groups: (1) placebo, (2) octreotide (100 microg), or (3) octreotide (200 microg) (n = 12 for each group). Thirty minutes postinjection a new baseline was established and measurements were repeated 30 and 60 minutes after the meal.

RESULTS

First study: Baseline portal pressure was 18.1 +/- 1.2 mm Hg, 30 and 60 minutes after the meal it was 21.5 +/- 0.8 mm Hg and 20.5 +/- 0.8 mm Hg, respectively (both P < 0.01 vs. baseline). Cardiac index (CI) was 4.5 +/- 0.2, 4.8 +/- 0.2, and 4.9 +/- 0.2 L x min(-1) x m(-2), respectively (both P < 0.05 vs. baseline). Peripheral vascular resistance was 1012 +/- 56, 902 +/- 51 (P = NS), and 884 +/- 49 dynes x sec x cm(-5) (P< 0.05 vs. baseline), respectively. Second study: Propranolol and placebo did not blunt postprandial increase in portal pressure. Octreotide (100 microg) partially ameliorated postprandial increase in portal pressure. Octreotide (200 microg) significantly enhanced the portal hypotensive effect of propranolol and blunted the postprandial increase in portal pressure.

CONCLUSIONS

Octreotide blunts postprandial increase in portal pressure not prevented by long-term propranolol administration.

Effects of somatostatin and octreotide on portal-systemic collaterals in portal hypertensive rats

BACKGROUND/AIMS

Somatostatin and its long-acting analogue, octreotide, have been used to cease variceal bleeding with uncertain mechanisms. This study investigated whether somatostatin and octreotide have a direct vasoconstrictive effect on the portal-systemic collaterals of portal-hypertensive rats and potentiate the vasoconstriction induced by endothelin-1 in these vascular beds.

METHODS

The vascular responses of collateral vessels to graded concentrations of somatostatin (10(-9)-10(-5) mol/l), octreotide (10(-10)-10(-6) mol/l), norepinephrine (10(-9)-10(-5) mol/l) and vehicle (Krebs solution) were evaluated in perfused collateral vascular beds of rats with portal hypertension induced by partial portal vein ligation. In addition, the perfusion pressure changes of collateral vessels to endothelin-1 (10(-8) mol/l) in the presence of vehicle(control), somatostatin (10(-6) mol/l) and octreotide (10(-6) mol/l) were tested.

RESULTS

Compared with the vehicle group, norepinephrine significantly increased the perfusion pressure of collateral vessels at concentrations between 10(-7) and 10(-5) mol/l. In contrast, neither somatostatin nor octreotide significantly changed the perfusion pressure. Somatostatin and octreotide significantly enhanced the endothelin-1-induced vasoconstrictive effect on the collaterals.

CONCLUSIONS

Somatostatin and octreotide exert no direct vasoconstrictive effect on the collateral vessels of portal hypertensive rats. In the presence of endothelin-1, somatostatin and octreotide exert a local vasoconstrictive effect on these vascular beds.

Somatostatin suppresses endothelin-1-induced rat hepatic stellate cell contraction via somatostatin receptor subtype 1

BACKGROUND & AIMS

Hepatic stellate cells (HSCs) are considered therapeutic targets to decrease portal hypertension. To elucidate some of the hemodynamic effects of somatostatin (SST) on portal pressure, the presence and function of SST receptors (SSTRs) on HSCs were investigated.

METHODS

SSTR messenger RNA expression, and SSTR presence was investigated using reverse-transcription polymerase chain reaction, real-time quantitative polymerase chain reaction, Western blotting, and immunohistochemistry. The function of SSTRs was studied by examining the effects of SST and specific SSTR agonists on endothelin-1(ET-1)-induced HSC contraction.

RESULTS

Specific amplicons for SSTR subtypes 1, 2, and 3 were demonstrated in rat liver and in activated HSCs. The presence of SSTR subtypes 1, 2, and 3 was confirmed by Western blotting. With immunohistochemistry, a strong staining of HSCs was obtained for SSTR subtypes 1, 2, and 3 in CCl4-treated rats, but not in normal rat liver. Incubation of HSCs on collagen gels with buffer, 10(-8) mol/L SST, and 2 x 10(-8) mol/L ET-1 resulted in collagen surface area decreases of 5.5% +/- 3.3%, 6.8% +/- 4.4%, and 49.8% +/- 8.3%, respectively. Relative contraction of gels preincubated with 10(-8) mol/L SST followed by 2 x 10(-8) mol/L ET-1 or vice versa as compared with maximal contraction (100%) with 2 x 10(-8) mol/L ET-1 were 72.6% +/- 17.9% and 76.2% +/- 12.6%, respectively (P < 0.05). SSTR agonist 1, but not SSTR agonist 2 or 3, was able to counteract the contractile effect of ET-1. CONCLUSIONA: Activated rat HSCs bear SSTR subtypes 1, 2, and 3. SST causes significant partial inhibition of ET-1-induced contraction of activated HSCs, mainly by stimulation of SSTR subtype 1.

Tonic control of peripheral cutaneous nociceptors by somatostatin receptors

The peptide somatostatin [somatotropin release-inhibiting factor (SRIF)] is widely distributed in the body and exerts a variety of hormonal and neural actions. Several lines of evidence indicate that SRIF is important in nociceptive processing: (1) it is localized in a subset of small-diameter dorsal root ganglion cells; (2) activation of SRIF receptors results in inhibition of both nociceptive behaviors in animals and acute and chronic pain in humans; (3) SRIF inhibits dorsal horn neuronal activity; and (4) SRIF reduces responses of joint mechanoreceptors to noxious rotation of the knee joint. The goal of the present study is to show that cutaneous nociceptors are under the tonic inhibitory control of SRIF. This is accomplished using behavioral and electrophysiological paradigms. In a dose-dependent manner, intraplantar injection of the SRIF receptor antagonist cyclo-somatostatin (c-SOM) results in nociceptive behaviors in normal animals and enhancement of nociceptive behaviors in formalin-injected animals, and these actions can be blocked when c-SOM is coapplied with three different SRIF agonists. Furthermore, intraplantar injection of SRIF antiserum also results in nociceptive behaviors. Electrophysiological recordings using an in vitro glabrous skin-nerve preparation show increased nociceptor activity in response to c-SOM, and this increase is blocked by the same three SRIF agonists. Parallel behavioral and electrophysiological studies using the opioid antagonist naloxone demonstrate that endogenous opioids do not maintain a tonic inhibitory control over peripheral nociceptors, nor does opioid receptor antagonism influence peripheral SRIF effects on nociceptors. These findings demonstrate that SRIF receptors maintain a tonic inhibitory control over peripheral nociceptors, and this may contribute to mechanisms that control the excitability of these terminals.

Bolus somatostatin but not octreotide reduces hepatic sinusoidal pressure by a NO-independent mechanism in chronic liver disease

BACKGROUND

Evidence exists that somatostatin and octreotide might have different effects on hepatic haemodynamics.

AIM

The investigation of the effects of somatostatin and its octapeptide analogue, octreotide, on sinusoidal pressure measured by the wedged hepatic venous pressure in patients with cirrhosis or chronic hepatitis and the correlation with the levels of hepatic vein NO.

METHODS

Patients were randomly assigned to receive an injection of either 250 microg somatostatin (n=14: cirrhosis six, chronic hepatitis eight) or an injection of 125 microg octreotide (n=19: cirrhosis nine, chronic hepatitis 10) during hepatic vein catheterization. Baseline wedged hepatic venous pressure was measured, followed by measurements at 2, 5, 10 and 15 min after the injection of the drug. Nitrites/nitrates of the hepatic vein were measured before the injection and after 15 min.

RESULTS

Both agents showed a similar qualitative but a different quantitative haemodynamic profile. No change in the wedged hepatic venous pressure was observed during the first 2 min after the injection of both drugs. This was followed by a decrease: 18% at 5 min (N.S.), 23% at 10 min (P < 0.01) and 24% at 15 min (P < 0.01) for somatostatin. Octreotide induced a relatively smaller decrease in the wedged hepatic venous pressure: 8% at 5 min (N.S.), 20% at 10 min (P < 0.01) and 16% at 15 min (N.S.). Further analysis of the sub-groups of cirrhotic and chronic hepatitis patients revealed a different effect. In the sub-group of cirrhotic patients, somatostatin caused a maximum decrease of 34% at 15 min post-injection (P < 0.01), but octreotide failed to produce a significant change on the wedged hepatic venous pressure. In contrast, no change was observed in chronic hepatitis patients with either drug. No change in the hepatic vein concentration of NO after treatment was observed with either somatostatin or octreotide. Moreover, no correlation of the levels of NO with the wedged hepatic venous pressure values was found.

CONCLUSIONS

This study shows that somatostatin is more effective than octreotide in acutely reducing the wedged hepatic venous pressure after bolus injection and the observed change is probably mediated by a NO-independent mechanism.

Portal hypertension

Portal hypertension is the main complication of cirrhosis and is responsible for its most common complications: variceal hemorrhage, ascites, and portosystemic encephalopathy. Portal hypertension is the result of increased intrahepatic resistance and increased portal venous inflow, which in turn is the result of splanchnic vasodilatation. Vasodilatation (splanchnic and systemic) and hyperdynamic circulation are hemodynamic abnormalities typical of cirrhosis and portal hypertension. Gastroesophageal varices result almost solely from portal hypertension, although the hyperdynamic circulation contributes to variceal growth and hemorrhage. Ascites results from sinusoidal hypertension and sodium retention, which is, in turn, secondary to vasodilatation and activation of neurohumoral systems. The hepatorenal syndrome represents the result of extreme vasodilatation with an extreme decrease in effective blood volume that leads to maximal activation of vasoconstrictive systems, renal vasoconstriction, and renal failure. Spontaneous bacterial peritonitis is a potentially lethal infection of ascites that occurs in the absence of a local source of infection. Portosystemic encephalopathy is a consequence of both portal hypertension (shunting of blood through portosystemic collaterals) and hepatic insufficiency that result in the accumulation of neurotoxins in the brain. This paper reviews the recent advances in the pathophysiology and management of the complications of portal hypertension.

Octreotide potentiates PKC-dependent vasoconstrictors in portal-hypertensive and control rats

BACKGROUND & AIMS

The effect of octreotide on vascular tone in the superior mesenteric artery (SMA) was studied in portal-hypertensive (portal vein-ligated) and sham-operated rats.

METHODS

In vitro-perfused SMA vascular beds were tested for the cumulative dose-response to octreotide at baseline conditions and after preconstriction with different vasoconstrictors (alpha1-agonist methoxamine, endothelin [ET-1], phorbol ester [PdBu], and potassium chloride [KCl]).

RESULTS

Octreotide did not affect baseline perfusion pressures (without preconstriction). alpha1-Adrenergic-, ET-1-, and PdBu-, but not KCl-, induced vasoconstriction was significantly potentiated by octreotide. This effect was dose-dependent and not different in portal vein-ligated and sham rats. Amplification of alpha1-adrenergic vasoconstriction by octreotide was significantly enhanced by nitric oxide inhibition (N(W)-nitro-L-arginine, 10(-4) mol/L) as well as by removal of the endothelium, and was completely suppressed by inhibition of protein kinase C (calphostin C, 1 micromol/L), phospholipase A2 (quinacrine, 5 micromol/L), and cyclooxygenase (indomethacin, 20 micromol/L).

CONCLUSIONS

Not directly, but in the presence of vasoconstrictors involving activation of protein kinase C, octreotide exerts a local vasoconstrictive effect on vascular smooth muscle of SMA. This potentiation is equipotent in portal vein-ligated and sham rats, immediate in onset, and mediated via phospholipase A2 and cyclooxygenase-derived prostanoids. This indicates that in preprandial conditions octreotide enhances the vasoconstrictive effect of dependent vasoconstrictors.

Desensitization to the effects of intravenous octreotide in cirrhotic patients with portal hypertension

BACKGROUND & AIMS

Octreotide has been suggested for the treatment of variceal bleeding, but detailed dose-finding studies are not available. We performed a dose-finding study investigating the hemodynamic effects of several forms of intravenous octreotide administration.

METHODS

Splanchnic hemodynamics and plasma glucagon levels were measured in 68 cirrhotics in baseline conditions and (1) after a double-blind intravenous injection of octreotide (50 microg [n = 9] or 500 microg [n = 8]) or placebo (n = 7); (2) after a 50-microg octreotide bolus followed by continuous infusion of 50 microg/h (n = 8), 250 microg/h (n = 8), or placebo (n = 6); (3) after repeated 50-microg injections of octreotide (n = 9) or placebo (n = 6) after an initial bolus (50 microg octreotide); and (4) after a placebo bolus and continuous octreotide infusion (50 microg/h; n = 7).

RESULTS

Placebo caused no significant changes. Octreotide caused a marked and transient decrease in portal pressure and azygos blood flow and an increase in mean arterial pressure. These effects lasted only 5 minutes despite addition of continuous octreotide infusions. Repeated octreotide injections had shorter, less marked effects than the first bolus. A continuous octreotide infusion did not decrease portal pressure. Glucagon levels were markedly reduced by octreotide, but gradually returned to baseline despite continuous infusions or repeated injections of octreotide.

CONCLUSIONS

Octreotide injection caused marked but transient reductions in portal pressure and azygos blood flow. Adding a continuous octreotide infusion neither maintained nor prolonged its effects. Repeated boluses caused significant tachyphylaxis. This rapid desensitization to the effects of octreotide may explain the divergent effects achieved with octreotide infusions in acute variceal bleeding.

Diagnosing portal hypertension

It is important to diagnose portal hypertension owing to its devastating complications. Clinicians need to be able to recognize physical signs and symptoms associated with portal hypertensive states. When in doubt, appropriate diagnostic measures need to be performed and a definite diagnosis made. Hepatic venous pressure gradient (HVPG) is often used as a surrogate measurement of portal pressure. HVPG can be obtained safely and conveniently on an outpatient basis. It can also be used to assess efficacy of various treatment modalities. Knowledge of pathophysiology of portal hypertension has provided the basis for further trials in both novel treatment modalities and diagnostic methods.