Use of Intravenous Hydroxocobalamin for Vasoplegic Syndrome in Simultaneous Liver-Kidney Transplant: A Case Report

Vasoplegia in Heart, Lung, or Liver Transplantation: A Narrative Review

Vasoplegia is a pathophysiologic state of hypotension in the setting of normal or high cardiac output and low systemic vascular resistance despite euvolemia and high-dose vasoconstrictors. Vasoplegia in heart, lung, or liver transplantation is of particular interest because it is common (approximately 29%, 28%, and 11%, respectively), is associated with adverse outcomes, and because the agents used to treat vasoplegia can affect immunosuppressive and other drug metabolism. This narrative review discusses the pathophysiology, risk factors, and treatment of vasoplegia in patients undergoing heart, lung, and liver transplantation. Vasoplegia in this patient population is associated with acute kidney injury, hospital length of stay, and even survival. The mechanisms of vasoplegia in this patient population likely involve multiple pathways, including nitric oxide synthase, cyclic guanylate cyclase, cytokine release, hydrogen sulfide, adrenal axis abnormalities, and vasopressin deficiency. Contributors to vasoplegia in this population include mechanical circulatory support such as extracorporeal membrane oxygenation and cardiopulmonary bypass, organ ischemia time, preexisting infection, and medications such as angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and excessive sedation. Treatment of vasoplegia in this population begins with conventional catecholamines and vasopressin analogs. Occasionally, agents, including methylene blue, hydroxocobalamin, and angiotensin II, are administered. Though retrospective literature suggests a hemodynamic response to these agents in the transplant population, minimal evidence is available to guide management. In what follows, we discuss the treatment of vasoplegia in the heart, lung, and liver transplant populations based on patient characteristics and potential risk factors associated with non-catecholamine agents.

A retrospective cohort analysis comparing the effectiveness and safety of perioperative angiotensin II to adrenergic vasopressors as a first-line vasopressor in kidney transplant recipients

BACKGROUND

Perioperative adrenergic vasopressors in kidney transplantation have been linked to negative outcomes and arrhythmias. Synthetic angiotensin II (AT2S) could improve renal hemodynamics, preserve allograft function, and reduce arrhythmias.

OBJECTIVE

We aimed to compare the effectiveness and safety of AT2S to adrenergic vasopressors when used for perioperative hypotension in kidney transplant.

METHODS

This single-center, retrospective cohort study included adults with perioperative shock requiring AT2S or adrenergic agents as first-line vasopressors during kidney transplant. The primary outcome was the need for a second continuous infusion vasopressor agents beyond the first-line agent. Secondary outcomes assessed adverse events and early allograft outcomes.

RESULTS

Twenty patients receiving AT2S and 60 patients receiving adrenergic vasopressor agents were included. Intraoperatively, 1 of 20 patients (5%) in the AT2S group needed a second continuous vasopressor compared to 7 of 60 patients (11.7%) who needed a second continuous vasopressor in the adrenergic vasopressor group (P = 0.672). Postoperatively, 1 of 20 patients (5%) in the AT2S group compared to 12 of 60 patients (20%) in the adrenergic vasopressor group required a second vasopressor (P = 0.168). There were significantly fewer arrhythmias (1/20 [5%] vs. 17/60 [28.3%]), P = 0.03) and ischemic complications (0/20 [0%] vs. 11/20 [18.3%], P = 0.031) in patients who received AT2S. There were no differences in immediate, slow, or delayed graft function or in discharge, 1-month, and 3-month glomerular filtration rates (p > 0.05). CONCLUSION AND RELEVANCE: Both AT2S and adrenergic vasopressors are effective for perioperative hypotension in kidney transplant, with AT2S showing a lower incidence of arrhythmias and ischemic complications.

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.

Use of Intramuscular Ephedrine Sulfate During Kidney Transplantation

Hypotension during kidney transplantation can be common. Vasopressor use during these procedures is often avoided, with a fear of decreasing renal perfusion in the transplanted kidney. However, adequate perfusion for the rest of the body is also necessary, and given that these patients often have underlying hypertension or other comorbid conditions, an appropriate mean arterial pressure (MAP) has to be maintained. Intramuscular injections of ephedrine have been studied in the anesthesiology literature in a variety of case types, and it is seen as a safe and effective method to boost MAP. We present a case series of three patients who underwent renal transplantation and who received an intramuscular injection of ephedrine for hypotension control. The medication worked well for increasing blood pressures without apparent side effects. All three patients were followed for more than one year, and all patients had good graft function at the end of that time period. This series shows that while further research is necessary in this arena, intramuscular ephedrine may have a place in the management of persistent hypotension in the operating room during kidney transplantation.

Hydroxocobalamin for Vasodilatory Hypotension in Shock: A Systematic Review With Meta-Analysis for Comparison to Methylene Blue

Hydroxocobalamin inhibits nitric oxide-mediated vasodilation, and has been used in settings of refractory shock. However, its effectiveness and role in treating hypotension remain unclear. The authors systematically searched Ovid Medline, Embase, EBM Reviews, Scopus, and Web of Science Core Collection for clinical studies reporting on adult persons who received hydroxocobalamin for vasodilatory shock. A meta-analysis was performed with random-effects models comparing the hemodynamic effects of hydroxocobalamin to methylene blue. The Risk of Bias in Nonrandomized Studies of Interventions tool was used to assess the risk of bias. A total of 24 studies were identified and comprised mainly of case reports (n = 12), case series (n = 9), and 3 cohort studies. Hydroxocobalamin was applied mainly for cardiac surgery vasoplegia, but also was reported in the settings of liver transplantation, septic shock, drug-induced hypotension, and noncardiac postoperative vasoplegia. In the pooled analysis, hydroxocobalamin was associated with a higher mean arterial pressure (MAP) at 1 hour than methylene blue (mean difference 7.80, 95% CI 2.63-12.98). There were no significant differences in change in MAP (mean difference -4.57, 95% CI -16.05 to 6.91) or vasopressor dosage (mean difference -0.03, 95% CI -0.12 to 0.06) at 1 hour compared to baseline between hydroxocobalamin and methylene blue. Mortality was also similar (odds ratio 0.92, 95% CI 0.42-2.03). The evidence supporting the use of hydroxocobalamin for shock is limited to anecdotal reports and a few cohort studies. Hydroxocobalamin appears to positively affect hemodynamics in shock, albeit similar to methylene blue.

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.

Intraoperative Use of Angiotensin II for Severe Vasodilatory Shock During Liver Transplantation: A Case Report

Refractory hypotension is a known entity in liver transplantation. Catecholamine and vasopressin infusions are first-line therapies. There has been recent interest in angiotensin II (Ang-2) as an alternative vasopressor; however, liver failure patients were excluded from the original trials. Ang-2 has potential in this patient population. This case discusses a patient who received an infusion of Ang-2 during a liver transplant for combined liver failure-induced distributive shock and septic shock. It is the first known successful use of intraoperative Ang-2 in this situation, and it shows that Ang-2 may be safe in liver transplantation when traditional therapies fail.