Does Telotristat Have a Role in Preventing Carcinoid Heart Disease?

Carcinoid heart disease (CHD) is a frequent and life-threatening complication in patients with carcinoid tumors. Its clinical management is challenging is some cases since serotonin-induced valve fibrosis leads to heart failure. Telotristat is an inhibitor of tryptophan-hydroxylase (TPH), a key enzyme in serotonin production. Telotristat use in patients with carcinoid syndrome and uncontrollable diarrhea under somatostatin analogs is approved, but its specific role in patients with CHD is still not clear. IN this context, we aimed to explore the effect of telotristat in heart fibrosis using a mouse model of serotonin-secreting metastasized neuroendocrine neoplasm (NEN). To this aim, four treatment groups (n = 10/group) were evaluated: control, monthly octreotide, telotristat alone, and telotristat combined with octreotide. Plasma serotonin and NT-proBNP levels were determined. Heart fibrosis was histologically evaluated after 6 weeks of treatment or when an individual mouse's condition was close to being terminal. Heart fibrosis was observed in all groups. Non-significant reductions in primary tumor growth were observed in all of the treated groups. Feces volume was increased in all groups. A non-significant decrease in feces volume was observed in the octreotide or telotristat-treated groups, while it was significantly reduced with the combined treatment at the end of the study compared with octreotide (52 g reduction; p < 0.01) and the control (44.5 g reduction; p = 0.05). Additionally, plasma NT-proBNP decreased in a non-significant, but clinically relevant, manner in the octreotide (28.2% reduction), telotristat (45.9% reduction), and the octreotide + telotristat (54.1% reduction) treatment groups. No significant changes were observed in plasma serotonin levels. A similar non-significant decrease in heart valve fibrosis was observed in the three treated groups. In conclusion, Telotristat alone and especially in combination with octreotide decreases NT-proBNP levels in a mouse model of serotonin-secreting metastasized NEN, when compared with the control and octreotide, but its effect on heart valve fibrosis (alone and in combination) was not superior to octreotide in monotherapy.

Vigilance for carcinoid heart disease is still required in the era of somatostatin analogues: Lessons from a case series.

AIM: Carcinoid heart disease (CHD) is a well-documented complication of neuroendocrine tumors (NETs) due to secreted hormones causing fibrosis. Somatostatin analogues (SSAs) can decrease hormonal secretion and inhibit tumor growth. The reported incidence of CHD has decreased as SSA use has increased. We describe a series of patients who have developed CHD even though they were treated with SSA therapy. METHODS: Nine patients were seen in four centers in Australia and New Zealand. The average duration of follow-up from diagnosis was 39 months. RESULTS: Three patients had Grade 1 and six Grade 2 disease by World Health Organization 2010 criteria. All patients had no CHD symptoms at baseline and started SSA therapy soon after diagnosis, yet developed significant, symptomatic cardiac dysfunction in their disease course. The median time from NET diagnosis to SSA initiation was 1 month, and median time from NET diagnosis to CHD diagnosis was 23 months (range 4-52). All patients who were tested had persistently increased hormonal levels (chromogranin A, urinary 5-hydroxyindolacetic acid). CONCLUSIONS: The good symptomatic control afforded by SSAs should not lead to reduced vigilance in screening for CHD, especially in patients with persistently elevated hormonal assays. Clinicians should consider regular echocardiographic screening in patients with a secretory syndrome.

mTOR Kinase Inhibition Effectively Decreases Progression of a Subset of Neuroendocrine Tumors that Progress on Rapalog Therapy and Delays Cardiac Impairment.

Inhibition of mTOR signaling using the rapalog everolimus is an FDA-approved targeted therapy for patients with lung and gastroenteropancreatic neuroendocrine tumors (NET). However, patients eventually progress on treatment, highlighting the need for additional therapies. We focused on pancreatic NETs (pNET) and reasoned that treatment of these tumors upon progression on rapalog therapy, with an mTOR kinase inhibitor (mTORKi), such as CC-223, could overcome a number of resistance mechanisms in tumors and delay cardiac carcinoid disease. We performed preclinical studies using human pNET cells in vitro and injected them subcutaneously or orthotopically to determine tumor progression and cardiac function in mice treated with either rapamycin alone or switched to CC-223 upon progression. Detailed signaling and RNA sequencing analyses were performed on tumors that were sensitive or progressed on mTOR treatment. Approximately 57% of mice bearing pNET tumors that progressed on rapalog therapy showed a significant decrease in tumor volume upon a switch to CC-223. Moreover, mice treated with an mTORKi exhibited decreased cardiac dilation and thickening of heart valves than those treated with placebo or rapamycin alone. In conclusion, in the majority of pNETs that progress on rapalogs, it is possible to reduce disease progression using an mTORKi, such as CC-223. Moreover, CC-223 had an additional transient cardiac benefit on valvular fibrosis compared with placebo- or rapalog-treated mice. These results provide the preclinical rationale to further develop mTORKi clinically upon progression on rapalog therapy and to further test their long-term cardioprotective benefit in those NET patients prone to carcinoid syndrome. Mol Cancer Ther; 16(11); 2432-41. ©2017 AACR.

Carcinoid heart disease: Diagnosis and management.

Hedinger syndrome refers to carcinoid valvular heart disease. The disease is believed to be triggered by vasoactive substances that result in valvular fibrosis. It classically occurs in patients with metastatic carcinoid and preferentially involves the right sided cardiac valves. Affected valves become thickened and retracted, exhibiting regurgitation and sometimes, stenosis. Echocardiography is recommended in patients with carcinoid syndrome and a follow up study is advisable in those who develop a murmur or other symptoms or signs of valvular heart disease. For appropriately selected patients, valve replacement surgery appears to improve outcomes.

A rare case of a carcinoid myocardial mass.

Right-sided valvular disease is characteristic of the carcinoid syndrome. In contrast, myocardial involvement is unusual. We present a case of an asymptomatic patient who had a myocardial carcinoid tumor discovered during surgery for coronary artery disease. The clinical presentation, diagnostic tests and modalities, and outcomes after surgery are discussed in this case report.

Serotonin receptors and heart valve disease--it was meant 2B.

Carcinoid heart disease was one of the first valvular pathologies studied in molecular detail, and early research identified serotonin produced by oncogenic enterochromaffin cells as the likely culprit in causing changes in heart valve tissue. Researchers and physicians in the mid-1960s noted a connection between the use of several ergot-derived medications with structures similar to serotonin and the development of heart valve pathologies similar to those observed in carcinoid patients. The exact serotonergic target that mediated valvular pathogenesis remained a mystery for many years until similar cases were reported in patients using the popular diet drug Fen-Phen in the late 1990s. The Fen-Phen episode sparked renewed interest in serotonin-mediated valve disease, and studies led to the identification of the 5-HT(2B) receptor as the likely molecular target leading to heart valve tissue fibrosis. Subsequent studies have identified numerous other activators of the 5-HT(2B) receptor, and consequently, the use of many of these molecules has been linked to heart valve disease. Herein, we: review the molecular properties of the 5-HT(2B) receptor including factors that differentiate the 5-HT(2B) receptor from other 5-HT receptor subtypes, discuss the studies that led to the identification of the 5-HT(2B) receptor as the mediator of heart valve disease, present current efforts to identify potential valvulopathogens by screening for 5-HT(2B) receptor activity, and speculate on potential therapeutic benefits of 5-HT(2B) receptor targeting.

Carcinoid syndrome diagnosed by echocardiography.

Right heart failure is a common presentation to both general physicians and cardiologists. Echocardiography is a useful investigation, and usually imaging of the liver is confined to helping estimate the right atrial pressure. We report a case of right heart failure where incidental imaging of the liver architecture during transoesophageal echocardiography helped in establishing the final diagnosis.

Evaluation of treatment with bosentan in patients with carcinoid heart disease: single center study.

BACKGROUND: The primary aim of this study was to evaluate a combined therapeutic intervention, including the dual endothelin receptor antagonist bosentan, in patients with carcinoid heart disease (CaHD). The efficacy of the treatment protocol was investigated using serological, echocardiographic, and clinical markers. PATIENTS AND METHODS: Since 2003, 40 patients with neuroendocrine tumours were identified; 14 had echocardiographic findings consistent with CaHD. Six of the 14 patients with CaHD and a New York Heart Association (NYHA) functional class >or= III received bosentan and were eligible for inclusion in this study. RESULTS: N-terminal pro-brain natriuretic peptide (NT-pro-BNP) had decreased 6 months after treatment with bosentan (median: 646 pg/ml vs. 400.5 pg/ml; p = 0.02); the right ventricular systolic pressure had decreased after 3 and 6 months (median: 69 mmHg vs. 61 mmHg, p = 0.02; median: 69 mmHg vs. 48.5 mmHg, p = 0.02); the 6-minute walk distance (6MWD) had significantly improved after 3 and 6 months of treatment (median: 293.5 vs. 406.5 m; p = 0.02; median: 293.5 vs. 578.5 m; p = 0.02). The NYHA functional class improved in 5/6 patients receiving bosentan. CONCLUSIONS: Combined treatment with bosentan is effective in patients with CaHD, based on functional class, 6MWD, and NT-pro-BNP. Further clarification of the CaHD fibrosis pathogenesis is needed to facilitate development of targeted antifibrotic therapeutic agents.

Management of patients undergoing multivalvular surgery for carcinoid heart disease: the role of the anaesthetist.

BACKGROUND: The management of patients with carcinoid heart disease poses two major challenges for the anaesthetist: carcinoid crisis and low cardiac output secondary to right ventricular (RV) failure. Carcinoid crises may be precipitated by the administration of catecholamines and histamine-releasing drugs. METHODS: We analysed a series of 11 patients [six males, median (range) age 60 (42-73) yr] with severe symptomatic carcinoid heart disease who underwent multivalve surgery (right-sided valves, n=8; right- and left-sided valves, n=3) between 2001 and 2007. RESULTS: All patients received octreotide intraoperatively [650 (300-1050) microg] to prevent carcinoid symptoms and vasoplegia. Those patients on a greater preoperative octreotide regime required additional intraoperative octreotide [median (range) dose 320 (300-850) vs 750 (650-1050) mug]. Similarly, the use of greater doses of aprotinin (> 5 KIU) was associated with greater requirements for octreotide [475 (300-700) vs 750 (320-1050) microg] and higher glucose levels (> or =8.5 mmol litre(-1)). Catecholamines were generally required in those patients who presented with a worse New York Heart Association functional class. Overall mortality was 18% (n=2) and only one episode of mild intraoperative carcinoid crisis was observed. CONCLUSIONS: Carcinoid crisis and RV failure still remain the primary challenges for the anaesthesiologist while managing patients with carcinoid heart disease. Our study supports the administration of catecholamines to wean patients off cardiopulmonary bypass, particularly in the presence of myocardial dysfunction. Those patients on higher octreotide dosages may require close intraoperative glucose monitoring. Despite high operative mortality, surgical outcome has been improved potentially due to earlier patient referral and better perioperative management.

Isolated severe tricuspid regurgitation: the importance of identifying underlying mechanism.

An 88-year-old woman presented with right heart failure, history of diarrhoea, abdominal pain, weight lost, dyspnoea over several weeks and a new pan-systolic murmur. Echocardiography showed retracted tricuspid leaflets with incomplete coaptation resulting in severe regurgitation. Subcostal view showed an adjacent hepatic cyst leading to biopsy, which revealed neoplastic neuroendocrine cells. Her 24-hour urinary 5-hydroxyindoleacetic acid level was elevated. The unifying diagnosis was carcinoid syndrome for which she was treated. Echocardiography is an important tool for diagnosis, management and prognosis of carcinoid heart disease.

Intraoperative management of patients with carcinoid heart disease having valvular surgery: a review of one hundred consecutive cases.

BACKGROUND: Cardiac surgery for carcinoid heart disease is complicated by hemodynamic instability secondary to carcinoid crises, cardiovascular dysfunction, and blood loss. The safety of vasopressors and the benefit of aprotinin during concomitant octreotide administration are uncertain. METHODS: We reviewed the effects of vasopressors and aprotinin on octreotide administration and mortality by univariate analysis in 100 consecutive cases of cardiac surgery for carcinoid heart disease from 1985 to 2003. Because mortality declines were temporally related to the introduction of aprotinin, bivariate analyses were performed to identify other factors associated with mortality. RESULTS: Carcinoid symptoms and hypotension were treated with octreotide (n = 89) and/or vasopressors (n = 93). Vasopressors were not associated with increased octreotide administration. Patients requiring epinephrine had higher mortality but also had worse preoperative New York Heart Association class, higher urinary 5-hydroxyindoleacetic acid levels, and increased blood transfusion requirements. Aprotinin (n = 54) was associated with decreased blood transfusion requirements, increased octreotide administration, but not mortality. Overall mortality was 13%, declining from 28% between 1985 and 1994 to 6% between 1995 and 2003. Mortality was associated with greater blood transfusion requirements and longer duration of cardiopulmonary bypass. CONCLUSIONS: Vasopressors may be used in conjunction with octreotide in carcinoid patients. The increased mortality associated with epinephrine likely reflects selection bias rather than a primary adverse effect. The improved survival over time in carcinoid patients is multifactorial and unrelated to aprotinin administration, suggesting further inhibition of the kallikrein-kinin system has little added benefit for this outcome in the presence of octreotide.

Carcinoid heart disease.

Carcinoid heart disease is a rare form of valvular heart disease. The management of these patients is complex, as the systemic malignant disease and the cardiac involvement have to be considered at the same time. Progress in the treatment of patients with carcinoid disease has resulted in improved symptom control and survival. Development and progression of carcinoid heart disease are associated with increased morbidity and mortality. In patients with severe cardiac involvement and well-controlled systemic disease, cardiac surgery has been recognized as the only effective treatment option. Valve replacement surgery may not only be beneficial in terms of symptom relief, but may also contribute to the improved survival observed over the past 2 decades in patients with carcinoid heart disease. Early diagnosis and early surgical treatment in appropriately selected patients may provide the best results. In this article, we review the current literature regarding the biology, diagnosis, treatment, and prognosis of carcinoid heart disease.