Hydroxocobalamin for Vasoplegic Syndrome in Liver Transplantation

Use of hydroxocobalamin to treat intraoperative vasoplegic syndrome refractory to vasopressors and methylene blue during liver transplantation

INTRODUCTION

For patients with catecholamine-resistant vasoplegic syndrome (VS) during liver transplantation (LT), treatment with methylene blue (MB) and/or hydroxocobalamin (B12) has been an acceptable therapy. However, data on the effectiveness of B12 is limited to case reports and case series.

METHODS

We retrospectively reviewed records of patients undergoing LT from January 2016 through March 2022. We identified patients with VS treated with vasopressors and MB, and abstracted hemodynamic parameters, vasopressor requirements, and B12 administration from the records. The primary aim was to describe the treatment efficacy of B12 for VS refractory to vasopressors and MB, measured as no vasopressor requirement at the conclusion of the surgery.

RESULTS

One hundred one patients received intraoperative VS treatment. For the 35 (34.7%) patients with successful VS treatment, 14 received MB only and 21 received both MB and B12. Of the 21 patients with VS resolution after receiving both MB and B12, 17 (89.5%) showed immediate, but transient, hemodynamic improvements at the time of MB administration and later showed sustained response to B12.

CONCLUSION

Immediate but transient hemodynamic response to MB in VS patients during LT supports the diagnosis of VS and should prompt B12 administration for sustained treatment response.

Vasoplegic Syndrome and Anaesthesia: A Narrative Review

Vasoplegic syndrome (VS) is defined as low systemic vascular resistance, normal or high cardiac output, and resistant hypotension unresponsive to vasopressor agents and intravenous volume. VS is a frequently encountered complication in cardiovascular and transplantation surgery, burns, trauma, pancreatitis, and sepsis. The basis of the pathophysiology is associated with an imbalance of vasodilator and vasoconstrictive structure in vascular smooth muscle cells and is highly complex. The pathogenesis of VS has several mechanisms, including overproduction of iNO, stimulation of ATP-dependent K+ channels and NF-κB, and vasopressin receptor 1A (V1A-receptor) down-regulation. Available treatments involve volume and inotropes administration, vasopressin, methylene blue, hydroxocobalamin, Ca++, vitamin C, and thiamine, and should also restore vascular tone and improve vasoplegia. Other treatments could include angiotensin II, corticosteroids, NF-κB inhibitor, ATP-dependent K+ channel blocker, indigo carmine, and hyperbaric oxygen therapy. Despite modern advances in treatment, the mortality rate is still 30-50%. It is challenging for an anaesthesiologist to consider this syndrome's diagnosis and manage its treatment. Our review aims to review the diagnosis, predisposing factors, pathophysiology, treatment, and anaesthesia approach of VS during anaesthesia and to suggest a treatment algorithm.

Hydroxocobalamin for treatment of catecholamine-resistant vasoplegia during liver transplantation: A single-center series of 20 cases

Introduction

Catecholamine-resistant vasoplegia is a potentially devastating complication during liver transplantation. Hydroxocobalamin has emerged as a treatment for vasoplegia associated with cardiac surgery, liver transplantation, and septic shock.

Presentation of case

We performed a retrospective review of patients who underwent liver transplantation between October 2015 and May 2020 to evaluate the efficiency of hydroxocobalamin in this setting.

Discussion

A total of 137 patients underwent liver transplantation, of which 20 received hydroxocobalamin for vasoplegia. Administration of hydroxocobalamin increased mean arterial pressure and reduced vasoactive drug requirements.

Conclusion

This case series adds to the previous individual reports describing the use of hydroxocobalamin during liver transplantation suggesting hydroxocobalamin can mitigate refractory hypotension from catecholamine resistant vasoplegia during liver transplantation.

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Hypotension or vasoplegia is commonly encountered in end-stage liver disease.

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Vasoplegia during liver transplant is a common and potentially devastating condition.

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Hydroxocobalamin has been reported to improve catecholamine resistant vasoplegia.

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Hydroxocobalamin is believed to work by scavenging gasotransmitters NO, CO, and H₂S.

The pharmacotherapeutic options in patients with catecholamine-resistant vasodilatory shock

INTRODUCTION

Septic and vasoplegic shock are common types of vasodilatory shock (VS) with high mortality. After fluid resuscitation and the use of catecholamine-mediated vasopressors (CMV), vasopressin, angiotensin II, methylene blue (MB) and hydroxocobalamin can be added to maintain blood pressure.

AREAS COVERED

VS treatment utilizes a phased approach with secondary vasopressors added to vasopressor agents to maintain an acceptable mean arterial pressure (MAP). This review covers additional vasopressors and adjunctive therapies used when fluid and catecholamine-mediated vasopressors fail to maintain target MAP.

EXPERT OPINION

Evidence supporting additional vasopressor agents in catecholamine resistant VS is limited to case reports, series, and a few randomized control trials (RCTs) to guide recommendations. Vasopressin is the most common agent added next when MAPs are not adequately supported with CMV. VS patients failing fluids and vasopressors with cardiomyopathy may have cardiotonic agents such as dobutamine or milrinone added before or after vasopressin. Angiotensin II, another class of vasopressor is used in VS to maintain adequate MAP. MB and/or hydoxocobalamin, vitamin C, thiamine and corticosteroids are adjunctive therapies used in refractory VS. More RCTs are needed to confirm the utility of these drugs, at what doses, which combinations and in what order they should be given.

Effects of a single bolus of hydroxocobalamin on hemodynamics in vasodilatory shock

PURPOSE

Hydroxocobalamin has been observed to cause transient hypertension in healthy subjects, but rigorous studies examining its efficacy are lacking.

MATERIALS AND METHODS

Adults in shock who received hydroxocobalamin from 2017 to 2021 were analyzed retrospectively. Hourly hemodynamics from 24 h before and after treatment were collected, and the difference and hourly change of mean arterial pressure (MAP), systolic blood pressure (SBP), diastolic blood pressure (DBP), and norepinephrine-equivalent dose (NED) were examined in mixed-effects models.

RESULTS

This study included 3992 hemodynamic data points from 35 patients and is the largest case series to date. In the mixed effects model, there was no difference in MAP 24-h after hydroxocobalamin administration (estimated fixed effect [EFE] -0.2 mmHg, p = 0.89). A two-piecewise mixed model found that the hourly change in MAP was not different from zero in either the pre-administration (EFE 0.0 mmHg/h, p = 0.80) or post-administration segments (EFE 0.0 mmHg/h, p = 0.55). Analysis of the SBP, DBP, and NED also found similar insignificant results.

CONCLUSIONS

Although hydroxocobalamin has been observed to cause hypertension in healthy subjects, our results suggest that in patients with shock, hydroxocobalamin may not be effective in improving hemodynamics at 24 h after administration.

Vasoplegia after cardiopulmonary bypass: A narrative review of pathophysiology and emerging targeted therapies

Cardiovascular disease remains the leading cause of death in the United States, and cardiopulmonary bypass is a cornerstone in the surgical management of many related disease states. Pathophysiologic changes associated both with extracorporeal circulation and shock can beget a syndrome of low systemic vascular resistance paired with relatively preserved cardiac output, termed vasoplegia. While increased vasopressor requirements accompany vasoplegia, related pathophysiologic mechanisms may also lead to true catecholamine resistance, which is associated with further heightened mortality. The introduction of a second non-catecholamine vasopressor, angiotensin II, and non-specific nitric oxide scavengers offers potential means by which to manage this challenging phenomenon. This narrative review addresses both the definition, risk factors, and pathophysiology of vasoplegia and potential therapeutic interventions.

Vasoplegic syndrome following cardiothoracic surgery-review of pathophysiology and update of treatment options

Vasoplegic syndrome is a common occurrence following cardiothoracic surgery and is characterized as a high-output shock state with poor systemic vascular resistance. The pathophysiology is complex and includes dysregulation of vasodilatory and vasoconstrictive properties of smooth vascular muscle cells. Specific bypass machine and patient factors play key roles in occurrence. Research into treatment of this syndrome is limited and extrapolated primarily from that pertaining to septic shock, but is evolving with the expanded use of catecholamine-sparing agents. Recent reports demonstrate potential benefit in novel treatment options, but large clinical trials are needed to confirm.

Use of High-Dose Hydroxocobalamin for Septic Shock: A Case Report

In this case report, we describe 2 patients with septic shock requiring high-dose vasopressors for hemodynamic support despite aggressive fluid resuscitation. After the administration of high-dose hydroxocobalamin for presumed septic vasoplegic syndrome, both patients had an immediate response to hydroxocobalamin with a rapid and lasting improvement of blood pressure that significantly reduced the need for vasopressor support.

High-Dose Vitamin B12 in Vasodilatory Shock: A Narrative Review

Vasodilatory shock, as observed in postoperative states and sepsis, is hallmarked by low systemic vascular resistance and low blood pressure compensated by increased cardiac output. Gasotransmitters, such as nitric oxide and hydrogen sulfide, are implicated in the development and perpetuation of vasodilatory shock. Established therapies do not target these physiologic drivers of vasodilation. Due to their nontoxic and pleotropic effects, micronutrients are being used as rescue therapy in postoperative vasoplegia and septic shock. Here, we outline the pathophysiology of vasodilatory shock, describe the rationale for vitamin B12 (hydroxocobalamin) in vasodilatory shock, and identify literature evaluating its use in vasoplegic states.

High-dose hydroxocobalamin in end-stage liver disease and liver transplantation

Distributive shock is a serious complication in patients with chronic or end-stage liver disease, and can be exacerbated by vasoplegia in this patient population. Vasoplegic syndrome (VS) is a state of shock refractory to catecholamines and vasopressin that is often multifactorial in liver failure patients, and can occur in any phase of liver transplantation (LT) [i.e., pre-transplantation, intraoperative, and post-transplantation]. Methylene blue (MB) has been a well-established pharmacologic therapy for VS. However, it has been known to cause dose-related toxicity. Hydroxocobalamin (HXC) is not currently FDA approved for the management of VS, but studies have demonstrated its ability to cause an increase in systolic blood pressure by hypothesized mechanisms with only minimal side effects. To date, only three other reports have demonstrated the use of HXC in LT patients, which highlighted its use both intraoperatively and post-transplantation. Our report illustrates the utility of HXC in four LT patients with VS. Two of these cases illustrate the usefulness of HXC in the pre-transplantation period, which has never been previously reported. HXC is a useful pharmaceutical agent in the management of VS, especially if contraindications to MB exist or in cases of MB-resistant vasoplegia. Further studies with large sample sizes are necessary to ascertain the optimal dosage of HXC in LT patients.

The use of intravenous hydroxocobalamin as a rescue in methylene blue-resistant vasoplegic syndrome in cardiac surgery

Vasoplegic syndrome is a well-recognized complication during cardiopulmonary bypass (CPB) and is associated with increased morbidity and mortality, especially when refractory to conventional vasoconstrictor therapy. This is the first reported case of vasoplegia on CPB unresponsive to methylene blue whereas responsive to hydroxocobalamin, which indicates that the effect of hydroxocobalamin outside of the nitric oxide system is significant or that the two drugs have a synergistic effect in one or multiple mechanisms.

Case report of high-dose hydroxocobalamin in the treatment of vasoplegic syndrome during liver transplantation

A 66-year-old man with cryptogenic cirrhosis secondary to nonalcoholic steatohepatitis presented for orthotopic liver transplantation. Following organ reperfusion, the patient developed vasoplegic syndrome, with arterial blood pressures of approximately 60-70/30-40 mm Hg (mean arterial pressure [MAP] <45 mm Hg) for >90 minutes. He required high-dose norepinephrine and vasopressin infusions, as well as i.v. bolus doses of norepinephrine and vasopressin to reach a goal MAP> 60 mm Hg. There was minimal response to a 2 mg/kg i.v. bolus of methylene blue. Following the administration of 5 g of i.v.hydroxocobalamin, the patient had a profound improvement in arterial blood pressure, with subsequent discontinuation of the vasopressin infusion and rapid reduction of norepinephrine infusion from 20 to 2 μg/min. While there have been several reports of the efficacy of hydroxocobalamin for vasoplegia after cardiopulmonary bypass, there have been only limited cases of hydroxocobalamin used in liver transplantation, and none with high-dose administration. We present a case of vasoplegic syndrome during liver transplantation that was refractory to high-dose vasopressors and methylene blue but responsive to high-dose i.v. hydroxocobalamin.

Persistent Hypotension and Cerebral Swelling Resulting From Mesenteric Traction Syndrome After Omental-to-Pial Pedicle Flap Transfer in a Young Woman With Refractory Moyamoya Disease: A Case Report

Superficial temporal arterial to middle cerebral arterial anastomosis is often the initial surgical treatment of Moyamoya disease. In refractory cases, placing a pedicle flap of omentum over the ischemic brain has resulted in clinical improvement or stabilization of symptoms. We present a case of persistent mesenteric traction syndrome manifested by hypotension unresponsive to conventional doses of vasopressors during and after pulling the omentum to the brain. As prostacyclin is a major mediator of hypotension from mesenteric traction syndrome and also a cerebral vasodilator, we discuss the possibility that brain swelling may be a manifestation of mesenteric traction syndrome.