Pharmacology of Octreotide: Clinical Implications for Anesthesiologists and Associated Risks. Anesthesiol Clin. 2017;35:327-339. [PMID: 28526153 DOI: 10.1016/j.anclin.2017.01.021]

Agonists, Antagonists and Receptors of Somatostatin: Pathophysiological and Therapeutical Implications in Neoplasias

Somatostatin is a peptide that plays a variety of roles such as neurotransmitter and endocrine regulator; its actions as a cell regulator in various tissues of the human body are represented mainly by inhibitory effects, and it shows potent activity despite its physiological low concentrations. Somatostatin binds to specific receptors, called somatostatin receptors (SSTRs), which have different tissue distributions and associated signaling pathways. The expression of SSTRs can be altered in various conditions, including tumors; therefore, they can be used as biomarkers for cancer cell susceptibility to certain pharmacological agents and can provide prognostic information regarding disease evolution. Moreover, based on the affinity of somatostatin analogs for the different types of SSTRs, the therapeutic range includes conditions such as tumors, acromegaly, post-prandial hypotension, hyperinsulinism, and many more. On the other hand, a number of somatostatin antagonists may prove useful in certain medical settings, based on their differential affinity for SSTRs. The aim of this review is to present in detail the principal characteristics of all five SSTRs and to provide an overview of the associated therapeutic potential in neoplasias.

Octreotide Causing Hyperkalemia: A Case Report and Review of the Literature

Octreotide, a synthetic analog of somatostatin, is widely utilized for its inhibitory effects on various hormones, including growth hormone, insulin, and glucagon. Its applications span conditions such as acromegaly, carcinoid tumors, and gastrointestinal bleeding due to its ability to reduce portal venous pressure. Additionally, it serves a crucial role in nuclear medicine imaging and the management of hepatorenal syndrome. We report a case of a 44-year-old man with type 2 diabetes mellitus (T2DM) and stage 5 chronic kidney disease (CKD), not yet on hemodialysis, who presented with persistent severe hypoglycemia. Despite multiple oral glucose administrations, his blood glucose levels remained critically low. The patient was treated with octreotide for sulfonylurea-induced hypoglycemia. However, he developed hyperkalemia as a side effect of octreotide treatment. Traditional therapies for sulfonylurea-induced hypoglycemia often involve intravenous and oral dextrose and glucagon, which may lead to recurrent hypoglycemia due to their stimulatory effects on insulin release. Octreotide directly inhibits insulin release from the pancreas, thus preventing rebound hypoglycemia. However, its administration in patients with renal impairment poses a risk of hyperkalemia due to its suppression of insulin-mediated cellular potassium uptake, and it should be used with caution. This case highlights the potential for life-threatening hyperkalemia induced by octreotide in non-dialysis CKD patients. Physicians must be vigilant about this side effect, particularly in patients with underlying renal impairment. Close monitoring of potassium levels and appropriate management strategies are essential to ensure the safe use of octreotide. This case aims to raise awareness and contribute to a better understanding of octreotide-induced hyperkalemia in CKD patients.

Anesthetic key points in a patient with a terminal ileum neuroendocrine tumor and a rare carcinoid left heart disease presented for non-cardiac surgery: case report

BACKGROUND

Carcinoid tumors are rare neuroendocrine malignancies presenting in an increasing number in our center. The incidence of carcinoid tumors is approximatively between 2.5 and 5 cases per 100,000 people of whom about 50% develop carcinoid syndrome. Once the carcinoid syndrome has developed, a carcinoid cardiomyopathy can occur. Carcinoid heart disease (CaHD) remains a serious and rare complication associated with a significant increase in morbidity and mortality. Although carcinoid tumors have been known and studied for several years, there are still scarce data on the anesthetic management and the peri operative period.

CASE PRESENTATION

We describe a case of a Caucasian 44-year-old woman with an unusual presentation of left CaHD with an ileal neuroendocrine tumor and liver metastases. Our preoperative somatostatin administration protocol, limit the cardiac damage. The maintenance of stable hemodynamics, the use of balanced anesthetic technique, all along with a good understanding of the pathology, played a major role in the successful management of anesthesia. This case report allows us to introduce our decision algorithm for the management of this type of pathology in our tertiary hospital, Cliniques Universitaires Saint-Luc.

CONCLUSION

Despite the paucity of data, anesthetic management of patients with carcinoid tumor can be safely performed with effective hemodynamic monitoring and a good understanding of the pathophysiology. Knowledge and application of a clear institutional algorithm for octreotide administration and multidisciplinary consultation at a referral center are essential for the management of these patients.

Complete Heart Block After Low Dose Octreotide Infusion for Esophageal Variceal Bleeding

Cirrhosis and chronic liver disease cause a myriad of systemic health problems mostly caused by the presence of portal hypertension. Esophageal varices are one result of portal hypertension. They can rupture and bleed, which can be catastrophic in already coagulopathic liver failure patients. We present a patient who presented with decompensated liver failure for transplant. He developed a severe and refractory gastrointestinal bleed and was put on an octreotide infusion to increase splanchnic flow and decrease portal pressures. He subsequently developed complete heart block. Understanding the mechanisms of octreotide is imperative due to its frequent use in medically complex patients.

Patent foramen ovale in carcinoid heart disease: The potential role for and risks of percutaneous closure prior to cardiothoracic surgery

Neuroendocrine tumours (NETs) are rare but once metastasised, can lead to the release of vasoactive substances into the systemic circulation, and the classical features of carcinoid syndrome (CS) such as flushing and diarrhoea. A consequence of CS is carcinoid heart disease (CHD) which primarily affects the right-sided heart valves and can eventually lead to right heart failure. In this cohort, tricuspid and/or pulmonary valve replacement provides symptomatic relief. A patent foramen ovale (PFO) in patients with CHD can lead to the shunting of oxygen deficient blood to the systemic circulation causing hypoxaemia and reduced exercise tolerance. Additionally, the haemodynamic changes caused by regurgitant right-sided heart valves can increase the patency of a PFO allowing the passage of vasoactive substances to the systemic circulation thereby affecting the left-sided heart valves. We present data on the incidence of PFO in patients referred for surgery at our centre, in which the standard approach is to close the defect at time of cardiothoracic surgery. In addition, we present a series of four cases that highlight how the option of percutaneous PFO closure prior to open valve surgery may reduce haemodynamic instability and open a window of opportunity to enhance preoperative status. Percutaneous PFO closure then acts as a bridge to definitive cardiothoracic surgery, although there are risks in such an approach.

Gastrointestinal Bleeding in Patients Supported with Left Ventricular Assist Devices: The Journey from Bridging to Destination

End-stage heart failure is a prevalent and fatal cardiovascular disease. Almost 1 in 4 cases of mortality in the United States is attributed to heart failure. Left ventricular assist devices (LVADs) have emerged as a safe destination therapy or bridge to transplant. Despite remarkable results, LVAD is associated with significant adverse events, such as gastrointestinal bleeding (GIB). In this review, we aimed to understand the incidence and prevalence, pathophysiologic mechanisms, predictors, diagnostic mechanisms, management, and preventative measures of GIB in patients with an LVAD. GIB is a common adverse event in patients with an LVAD with an incidence of 15% to 25%. The exact pathogenesis of GIB is poorly understood. However, different mechanisms of bleeding have been described, such as arteriovenous malformations, acquired von Willebrand syndrome, coagulopathy, and treatment with antithrombotic therapy. Upper GIB is the most common site of GIB in patients with an LVAD. The management of GIB in patients with LVAD includes ensuring hemodynamic stability, holding or reversing antithrombotic therapy, and investigating and controlling the source of GIB through diagnostic and interventional endoscopic and radiologic means. Prophylactic medication use (e.g., danazol, octreotide, and bevacizumab) can decrease the risk of GIB in patients with an LVAD by decreasing arteriovenous malformations. Despite that the overall risk of GIB has decreased with new advancements in LVAD technology, further studies are needed regarding predictors, risk stratification, and optimal antithrombotic therapy to minimize the morbidity and mortality in patients with an LVAD. In conclusion, prompt diagnosis and management in a multidisciplinary team approach are crucial and lifesaving in such a life-threatening condition.

Targeting neuroendocrine tumors with octreotide and lanreotide: Key points for clinical practice from NET specialists

Octreotide and lanreotide are the two somatostatin analogs (SSA) currently available in clinical practice. They have been approved first to control the clinical syndrome (mainly carcinoid syndrome) associated with functioning neuroendocrine tumors (NET) and later for tumor growth control in advanced low/intermediate grade NET. Although evidence regarding their role, especially as antiproliferative therapy, has been increasing over the years some clinical indications remain controversial. Solicited by AIOM (Italian Association of Medical Oncology) a group of clinicians from various specialties, including medical oncology, endocrinology, and gastroenterology, deeply involved in NET for their clinical and research activity, addressed eight open questions, critically reviewing evidence and guidelines and sharing clinical take-home messages. The questions regarded the use of long-acting octreotide and lanreotide in the following settings: functioning and non-functioning NET refractory to label dose, first-line metastatic pulmonary NET, combination with other therapy with an antiproliferative intent, maintenance in NET responding to other therapies, adjuvant treatment, Ki-67-related cut-off, somatostatin receptor imaging, safety, and feasibility. The level of evidence is not absolute for the majority of these clinical contexts, so it is recommended to distinguish routine versus sporadic utilization in very selected cases. Mention of such specific issues by the main European guidelines (ENETS, European Neuroendocrine Tumor Society, and ESMO, European Society for Medical Oncology) was explored and their position reported. However, different clinical decisions on single patients could be made if the case is carefully discussed within a NET-dedicated multidisciplinary team.

WITHDRAWN: Dealing With the Right Side: Carcinoid Heart Disease

The Publisher regrets that this article is an accidental duplication of an article that has already been published in Journal of Cardiothoracic and Vascular Anesthesia, 36 (2022) 2793-2802, http://dx.doi.org/10.1053/j.jvca.2021.10.030. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

Carcinoid Crisis: A Misunderstood and Unrecognized Oncological Emergency

Carcinoid Crisis represents a rare and extremely dangerous manifestation that can occur in patients with Neuroendocrine Tumors (NETs). It is characterized by a sudden onset of hemodynamic instability, sometimes associated with the classical symptoms of carcinoid syndrome, such as bronchospasm and flushing. Carcinoid Crisis seems to be caused by a massive release of vasoactive substances, typically produced by neuroendocrine cells, and can emerge after abdominal procedures, but also spontaneously in rare instances. To date, there are no empirically derived guidelines for the management of this cancer-related medical emergency, and the available evidence essentially comes from single-case reports or dated small retrospective series. A transfer to the Intensive Care Unit may be necessary during the acute setting, when the severe hypotension becomes unresponsive to standard practices, such as volemic filling and the infusion of vasopressor therapy. The only effective strategy is represented by prevention. The administration of octreotide, anxiolytic and antihistaminic agents represents the current treatment approach to avoid hormone release and prevent major complications. However, no standard protocols are available, resulting in great variability in terms of schedules, doses, ways of administration and timing of prophylactic treatments.

Hydrophilic Interaction Liquid Chromatography Coupled with Fluorescence Detection (HILIC-FL) for the Quantitation of Octreotide in Injection Forms

Octreotide is a synthetic cyclic octapeptide analogue of somatostatin-14. It is mainly administered for the treatment of acromegaly, severe diarrhea, and neuroendocrine neoplasias. In this work, a hydrophilic interaction liquid chromatography (HILIC) method with fluorescence (FL) detection was developed and validated for the quantitation of octreotide in solutions for injection. Chromatographic separation was performed on an XBridge®-HILIC analytical column under isocratic elution with a short chromatographic run time of less than 10 min. The mobile phase consisted of ammonium bicarbonate 8.6 mM (pH 8.1)/acetonitrile 35/65 (v/v). The high sensitivity and selectivity of the fluorescence detection, with the excitation wavelength (λexcitation) set at 280 nm and the emission wavelength set at (λemission) 330 nm, enabled a simple sample preparation procedure that included only dilution steps. The calibration curve showed good linearity with a correlation coefficient greater than 0.998. The method was successfully applied to the analysis of commercially available octreotide injection forms.

Type I interferon mediated induction of somatostatin leads to suppression of ghrelin and appetite thereby promoting viral immunity in mice

Loss of appetite (anorexia) is a typical behavioral response to infectious diseases that often reduces body weight. Also, anorexia can be observed in cancer and trauma patients, causing poor quality of life and reduced prospects of positive therapeutic outcomes. Although anorexia is an acute symptom, its initiation and endocrine regulation during antiviral immune responses are poorly understood. During viral infections, plasmacytoid dendritic cells (pDCs) produce abundant type I interferon (IFN-I) to initiate first-line defense mechanisms. Here, by targeted ablation of pDCs and various in vitro and in vivo mouse models of viral infection and inflammation, we identified that IFN-I is a significant driver of somatostatin (SST). Consequently, SST suppressed the hunger hormone ghrelin that led to severe metabolic changes, anorexia, and rapid body weight loss. Furthermore, during vaccination with Modified Vaccinia Ankara virus (MVA), the SST-mediated suppression of ghrelin was critical to viral immune response, as ghrelin restrained the production of early cytokines by natural killer (NK) cells and pDCs, and impaired the clonal expansion of CD8⁺ T cells. Thus, the hormonal modulation of ghrelin through SST and the cytokine IFN-I is fundamental for optimal antiviral immunity, which comes at the expense of calorie intake.

Intraoperative Hypotension Increased Risk in the Oncological Patient

Patient safety advocacy involves avoiding, preventing, and amelioration of adverse outcomes or injuries caused by the process of healthcare rather than a patient's underlying medical illness. Intraoperative hypotension (IOH), a common morbid event, reduces perfusion to critical organs and tissues and has a wide incidence, depending on how it is defined. IOH has adverse intraoperative and postoperative consequences, which make its prevention important to improve patient outcomes. Certain populations have even greater consequences related to IOH, and clinicians must understand these risks. In this narrative review, we examine the risk of intraoperative hypotension in the oncological patient population.

Incidental Diagnosis of Carcinoid Disease by Intraoperative Transesophageal Echocardiography and Subsequent Discovery of a Neuroendocrine Tumor during Cardiac Surgery

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Carcinoid heart disease typically involves the right-sided valves of the heart.

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Carcinoid valves are fixed and retracted with limited mobility.

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Pathognomonic appearance of valves increases carcinoid likelihood.

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Carcinoid diagnosis has intraoperative implications.

Octreotide and lanreotide decrease ovarian ischemia-reperfusion injury in rats by improving oxidative and nitrosative stress

AIM

To investigate the protective effect of octreotide and lanreotide on ovarian damage in experimental ovarian ischemia-reperfusion injury.

METHODS

Fifty-six rats were separated into seven groups; group 1: sham group, group 2: surgical control group with 3-h torsion and detorsion, group 3: 0.02 mg/kg s.c. octreotide 30 min before 3-h torsion, group 4; octreotide just after detorsion for 7 days, group 5: octreotide 30 min before torsion and just after detorsion for 7 days, group 6: single time 20 mg/kg s.c. lanreotide before torsion, group 7: single time lanreotide just after detorsion.

RESULTS

All histopathological scores except congestion were significantly lower in group 1 than other groups. In addition, hemorrhage (group 2 vs 4: P < 0.05), degeneration (group 2 vs 4: P < 0.05, group 2 vs 5: P < 0.01 and group 2 vs 6: P < 0.05) and total damage score (group 2 vs 4: P < 0.05, group 2 vs 5: P < 0.05, group 2 vs 6: P < 0.05 and group 2 vs 7: P < 0.05) were significantly lower than other groups. Moreover, ovarian tissue total oxidant status and oxidative stress index levels were significantly decreased in groups 5 (both P < 0.05) and 7 (both P < 0.05) when compared to group 2. Furthermore, tissue levels of peroxynitrite were significantly higher in group 2 than groups 1, 3 and 5 (all P < 0.05).

CONCLUSIONS

Octreotide and lanreotide have a protective role against ischemia-reperfusion damage in rat torsion detorsion model by improving histopathological and biochemical findings including tissue levels of total oxidant status, oxidative stress index and peroxynitrite.

Treatment of gastrointestinal bleeding in left ventricular assist devices: A comprehensive review

Left ventricular assist devices (LVAD) are increasingly become common as life prolonging therapy in patients with advanced heart failure. Current devices are now used as definitive treatment in some patients given the improved durability of continuous flow pumps. Unfortunately, continuous flow LVADs are fraught with complications such as gastrointestinal (GI) bleeding that are primarily attributed to the formation of arteriovenous malformations. With frequent GI bleeding, antiplatelet and anticoagulation therapies are usually discontinued increasing the risk of life-threatening events. Small bowel bleeds account for 15% as the source and patients often undergo multiple endoscopic procedures. Treatment strategies include resuscitative measures and endoscopic therapies. Medical treatment is with octreotide. Novel treatment options include thalidomide, angiotensin converting enzyme inhibitors/angiotensin II receptor blockers, estrogen-based hormonal therapies, doxycycline, desmopressin and bevacizumab. Current research has explored the mechanism of frequent GI bleeds in this population, including destruction of von Willebrand factor, upregulation of tissue factor, vascular endothelial growth factor, tumor necrosis factor-α, tumor growth factor-β, and angiopoetin-2, and downregulation of angiopoetin-1. In addition, healthcare resource utilization is only increasing in this patient population with higher admissions, readmissions, blood product utilization, and endoscopy. While some of the novel endoscopic and medical therapies for LVAD bleeds are still in their development stages, these tools will yet be crucial as the number of LVAD placements will likely only increase in the coming years.

Diagnosis and management of chyle leak following axillary dissection

Chyle leak following oncological breast and axillary surgery is a rare complication with small number of reported cases in the literature and little formal guidance regarding management. We present a review of the current literature and further related guidance from other specialties, along with suggested strategies for identification, diagnosis and management of this uncommon but potentially significant complication.

Prophylactic octreotide does not reduce the incidence of postoperative chylothorax following lobectomy: Results from a retrospective study

Chylothorax after lobectomy is common, lacking reliable preventive measures. Octreotide is widely used for treatment of chyle leakage, but its role in preventing chylothorax has not been estimated. The aim of this study was to evaluate whether prophylactic octreotide could reduce the incidence of postoperative chylothorax.Patients who underwent lobectomy for lung cancer from January 2016 to September 2018 were retrospectively reviewed. The cases in prophylactic group received octreotide 1 day before the surgery until removal of chest tubes, while those in the control group did not use it unless the diagnosis of chylothorax.A total of 379 patients were enrolled, with 190 patients in control and 189 cases in prophylactic group. Octreotide was well tolerated in patients who received this agent. No 30-day mortality was indicated. Seven cases in control (3.7%, 7/190) and 3 cases in prophylactic group (1.6%, 3/189) with chylothorax were observed (P = .337). The patients in prophylactic group showed shorter duration of chest drainage ([3.6 ± 1.6] days vs [4.1 ± 2.0] days, P = .006) and reduced drainage volume ([441.8 ± 271.1] mL vs [638.7 ± 463.3] mL, P < .001). In addition, they showed similar stations and numbers of dissected lymph nodes, surgery-related complications, and postoperative hospital stay. Besides, 11 (5.8%, 11/190) patients in control and 6 (3.2%, 6/189) cases in the prophylactic group were readmitted for pleural effusion needing reinsertion of chest tubes (P = .321). Moreover, multivariable logistic analysis showed that induction therapy (odds ratio [OR] =12.03; 95% confidence interval [CI] 3.15-46.03, P < .001) was a risk factor, while high-volume experience of the surgeon (OR = 0.23; 95% CI 0.06-0.97, P = .045) was a preventive factor of surgery-related chylothorax. Additionally, prophylactic octreotide (OR = 0.18; 95% CI 0.11-0.28, P < .001) and perioperative low-fat diet (OR = 0.46; 95% CI 0.29-0.73, P = .001) were negatively associated with the drainage volume of pleural effusion. Furthermore, high-volume experience of the surgeon (OR = 6.03; 95% CI 1.30-27.85, P = .021) and induction therapy (OR = 8.87; 95% CI 2.97-26.48, P < .001) were risk factors of unplanned readmission.Prophylactic octreotide does not reduce the incidence of postoperative chylothorax or unplanned readmission following anatomic lobectomy. The routine application of octreotide should not be recommended. High-quality trials are required to validate these findings.

Periprocedural Management of Patients Undergoing Liver Resection or Embolotherapy for Neuroendocrine Tumor Metastases

OBJECTIVES

The objective of this study was to describe the periprocedural management of patients with well-differentiated neuroendocrine tumors with hepatic metastases who underwent liver-directed procedures.

METHODS

We performed a retrospective review of patients with metastatic neuroendocrine tumors who underwent liver resection, ablation, or embolotherapy at a single center from 2012 to 2016. The primary outcome was occurrence of documented carcinoid crisis (CC) or hemodynamic instability (HDI), defined as 10 minutes or more of systolic blood pressure less than 80 or greater than 180 mm Hg, or pulse greater than 120 beats per minute.

RESULTS

We identified 75 patients who underwent liver resection/ablation (n = 38) or embolotherapy (n = 37). Twenty-four patients (32%) experienced CC or HDI (CC/HDI); CC occurred in 3 patients. No clinicopathologic or procedural factors, including procedure type, octreotide or long-acting somatostatin analog use, and history of carcinoid syndrome, were associated with CC/HDI. Grades 2 to 4 complications were reported in 42% of patients who experienced CC/HDI versus in 16% of patients who did not experience CC/HDI (P < 0.05).

CONCLUSIONS

A significant portion of patients developed CC/HDI, and these patients were more likely to develop severe postprocedural complications. Periprocedural octreotide use was not associated with lower CC/HDI occurrence, but continued use is advised given its safety profile until additional studies definitively demonstrate lack of benefit.

4-Valve Heart Disease and Right Heart Failure

Carcinoid heart disease is a rare form of heart disease due to secretion of vasoactive compounds, including serotonin, from gastrointestinal tumors. This E-challenge examines the case of a patient with advanced carcinoid heart disease who presented to the operating room (OR) for a tricuspid valve replacement. Once the patient was in the OR, intraoperative transesophageal echocardiography was used to discover a patent foramen ovale and involvement of all 4 valves with regurgitant lesions. The patient underwent tricuspid valve replacement, pulmonic valve replacement, right ventricular outflow tract reconstruction, and patent foramen closure in the OR and experienced subsequent fulminant right heart failure. Mechanical circulatory support was required to separate the patient from cardiopulmonary bypass, which was first attempted with an intra-aortic balloon pump and subsequently achieved with implantation of a right ventricular assist device. Multiple reports of acute right heart failure are available in the literature; however, this case helps illustrate several important considerations for the anesthesiologist. The effects of chronic circulating vasoactive compounds on the heart valves are well documented; however, it is likely that advanced carcinoid heart disease also will trigger pre-existing myocardial dysfunction, which may be underappreciated. Identifying patients who are at high risk for intraoperative right heart failure and considering what constitutes an adequate preoperative assessment of right heart function aid in preparing for OR management. In addition, reviewing the potential options for managing these patients when the traditional therapies are inadequate, including mechanical support and extracorporeal circulation, is a useful exercise in preparation. This case also highlights the contributions of intraoperative transesophageal echocardiography in the diagnosis and management of carcinoid heart disease, the need for additional preoperative optimization of these patients, and the management and potential complications of mechanical support.

Carcinoid-syndrome: recent advances, current status and controversies

PURPOSE OF REVIEW

To review recent advances and controversies in all aspects of carcinoid-syndrome.

RECENT FINDINGS

Over the last few years there have been a number of advances in all aspects of carcinoid syndrome as well as new therapies. These include new studies on its epidemiology which demonstrate it is increasing in frequency; increasing insights into the pathogenesis of its various clinical manifestations and into its natural history: definition of prognostic factors; new methods to verify its presence; the development of new drugs to treat its various manifestations, both initially and in somatostatin-refractory cases; and an increased understanding of the pathogenesis, natural history and management of carcinoid heart disease. These advances have generated several controversies and these are also reviewed.

SUMMARY

There have been numerous advances in all aspects of the carcinoid-syndrome, which is the most common functional syndrome neuroendocrine tumors produce. These advances are leading to new approaches to the management of these patients and in some cases to new controversies.