Clinical Experience With IV Angiotensin II Administration: A Systematic Review of Safety

Angiotensin ii therapy in refractory septic shock: which patient can benefit most? A narrative review

Patients with septic shock who experience refractory hypotension despite adequate fluid resuscitation and high-dose noradrenaline have high mortality rates. To improve outcomes, evidence-based guidelines recommend starting a second vasopressor, such as vasopressin, if noradrenaline doses exceed 0.5 µg/kg/min. Recently, promising results have been observed in treating refractory hypotension with angiotensin II, which has been shown to increase mean arterial pressure and has been associated with improved outcomes. This narrative review aims to provide an overview of the pathophysiology of the renin-angiotensin system and the role of endogenous angiotensin II in vasodilatory shock with a focus on how angiotensin II treatment impacts clinical outcomes and on identifying the population that may benefit most from its use.

Target flow deviations on the cardiopulmonary bypass cause postoperative delirium in cardiothoracic surgery-a retrospective study evaluating temporal fluctuations of perfusion data

OBJECTIVES

Postoperative delirium (POD) is common, costly and associated with long-term morbidity and increased mortality. We conducted a cohort study to assess the contribution of cardiopulmonary bypass (CPB) to the development of POD by means of algorithm-based data processing.

METHODS

A database was compiled from 3 datasets of patients who underwent cardiac surgery between 2014 and 2019: intensive care unit discharge files, CPB protocols and medical quality management records. Following data extraction and structuring using novel algorithms, missing data were imputed. Ten independent imputations were analysed by multiple logistic regression with stepwise deletion of factors to arrive at a minimal adequate model.

RESULTS

POD was diagnosed in 456/3163 patients (14.4%). In addition to known demographic risk factors and comorbidities like male sex, age, carotid disease, acute kidney failure and diabetes mellitus, cardiopulmonary parameters like total blood volume at the CPB [adjusted odds ratio (AOR) 1.001; confidence interval (CI) 1.1001-1.002] were independent predictors of POD. Higher values of the minimal blood flow were associated with a lower risk of POD (AOR 0.993; CI 0.988-0.997). Flow rates at least 30% above target did emerge in the minimal adequate model as a potential risk factor, but the confidence interval suggested a lack of statistical significance (AOR 1.819; 95% CI: 0.955-3.463).

CONCLUSIONS

CPB data processing proved to be a useful tool for obtaining compact information to better identify the roles of individual operational states. Strict adherence to perfusion limits along with tighter control of blood flow and acid-base balance during CPB may help to further decrease the risk of POD.

Medical therapy of cardiogenic shock: Contemporary use of inotropes and vasopressors

Cardiogenic shock is a primary cardiac disorder that results in both clinical and biochemical evidence of tissue hypoperfusion and can lead to multi-organ failure and death depending on its severity. Inadequate cardiac contractility or cardiac power secondary to acute myocardial infarction remains the most frequent cause of cardiogenic shock, although its contribution has declined over the past two decades, compared with other causes. Despite some advances in cardiogenic shock management, this clinical syndrome is still burdened by an extremely high mortality. Its management is based on immediate stabilization of haemodynamic parameters so that further treatment, including mechanical circulatory support and transfer to specialized tertiary care centres, can be accomplished. With these aims, medical therapy, consisting mainly of inotropic drugs and vasopressors, still has a major role. The purpose of this article is to review current evidence on the use of these medications in patients with cardiogenic shock and discuss specific clinical settings with indications to their use.

Angiotensin II for Vasodilatory Hypotension in Patients Requiring Mechanical Circulatory Support

Background: Patients supported on mechanical circulatory support devices experience vasodilatory hypotension due to high surface area exposure to nonbiological and non-endothelialized surfaces. Angiotensin II has been studied in general settings of vasodilatory shock, however concerns exist regarding the use of this vasopressor in patients with pre-existing cardiac failure. The objective of this study was to assess the systemic and central hemodynamic effects of angiotensin II in patients with primary cardiac or respiratory failure requiring treatment with mechanical circulatory support devices. Methods: Multicenter retrospective observational study of adults supported on a mechanical circulatory support device who received angiotensin II for vasodilatory shock. The primary outcome was the intraindividual change from baseline in mean arterial pressure (MAP) and vasopressor dosage after angiotensin II. Results: Fifty patients were included with mechanical circulatory devices that were primarily used for cardiac failure (n = 41) or respiratory failure (n = 9). At angiotensin II initiation, the norepinephrine equivalent vasopressor dosage was 0.44 (0.34, 0.64) and 0.47 (0.33, 0.73) mcg/kg/min in the cardiac and respiratory groups, respectively. In the cardiac group, MAP increased from 60 to 70 mmHg (intraindividual P < .001) in the 1 h after angiotensin II initiation and the vasopressor dosage declined by 0.04 mcg/kg/min (intraindividual P < .001). By 12 h, the vasopressor dosage declined by 0.16 mcg/kg/min ( P = .001). There were no significant changes in cardiac index or mean pulmonary artery pressure throughout the 12 h following angiotensin II. In the respiratory group, similar but nonsignificant effects at 1 h on MAP (61-81 mmHg, P = .26) and vasopressor dosage (decline by 0.13 mcg/kg/min, P = .06) were observed. Conclusions: In patients requiring mechanical circulatory support for cardiac failure, angiotensin II produced beneficial systemic hemodynamic effects without negatively impacting cardiac function or pulmonary pressures. The systemic hemodynamic effects in those with respiratory failure were nonsignificant due to limited sample size.

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.

Alternatives to norepinephrine in septic shock: Which agents and when?

Vasopressors are the cornerstone of hemodynamic management in patients with septic shock. Norepinephrine is currently recommended as the first-line vasopressor in these patients. In addition to norepinephrine, there are many other potent vasopressors with specific properties and/or advantages that act on vessels through different pathways after activation of specific receptors; these could be of interest in patients with septic shock. Dopamine is no longer recommended in patients with septic shock because its use is associated with a higher rate of cardiac arrhythmias without any benefit in terms of mortality or organ dysfunction. Epinephrine is currently considered as a second-line vasopressor therapy, because of the higher rate of associated metabolic and cardiac adverse effects compared with norepinephrine; however, it may be considered in settings where norepinephrine is unavailable or in patients with refractory septic shock and myocardial dysfunction. Owing to its potential effects on mortality and renal function and its norepinephrine-sparing effect, vasopressin is recommended as second-line vasopressor therapy instead of norepinephrine dose escalation in patients with septic shock and persistent arterial hypotension. However, two synthetic analogs of vasopressin, namely, terlipressin and selepressin, have not yet been employed in the management of patients with septic shock, as their use is associated with a higher rate of digital ischemia. Finally, angiotensin Ⅱ also appears to be a promising vasopressor in patients with septic shock, especially in the most severe cases and/or in patients with acute kidney injury requiring renal replacement therapy. Nevertheless, due to limited evidence and concerns regarding safety (which remains unclear because of potential adverse effects related to its marked vasopressor activity), angiotensin Ⅱ is currently not recommended in patients with septic shock. Further studies are needed to better define the role of these vasopressors in the management of these patients.

Vasopressors and Risk of Acute Mesenteric Ischemia: A Worldwide Pharmacovigilance Analysis and Comprehensive Literature Review

Vasodilatory shock, such as septic shock, requires personalized management which include adequate fluid therapy and vasopressor treatments. While these potent drugs are numerous, they all aim to counterbalance the vasodilatory effects of a systemic inflammatory response syndrome. Their specific receptors include α- and β-adrenergic receptors, arginine-vasopressin receptors, angiotensin II receptors and dopamine receptors. Consequently, these may be associated with severe adverse effects, including acute mesenteric ischemia (AMI). As the risk of AMI depends on drug class, we aimed to review the evidence of plausible associations by performing a worldwide pharmacovigilance analysis based on the World Health Organization database, VigiBase®. Among 24 million reports, 104 AMI events were reported, and disproportionality analyses yielded significant association with all vasopressors, to the exception of selepressin. Furthermore, in a comprehensive literature review, we detailed mechanistic phenomena which may enhance vasopressor selection, in the course of treating vasodilatory shock.

A Multicenter Observational Cohort Study of Angiotensin II in Shock

INTRODUCTION

Angiotensin II (Ang-2) is a non-catecholamine vasopressor that targets the renin-angiotensin-aldosterone system by agonism of the angiotensin type 1 receptor. Its utility as a vasopressor and a catecholamine-sparing agent was demonstrated in the pivotal ATHOS-3 trial, and numerous post-hoc analyses have shown reduced mortality in certain subsets of the population.

METHODS

Consecutive adult patients at 5 centers who received Ang-2 from 2017-2020 were included in this multicenter, retrospective observational cohort study. Patient demographics, hemodynamics, and adverse events were collected. The primary outcomes of the study were the mean difference in MAP and norepinephrine (NEpi)-equivalent dose at hours 0 and 3 following initiation of Ang-2 therapy.

RESULTS

One hundred and sixty-two patients were included in this study. The primary outcomes of an increase in MAP (mean difference 9.3 mmHg, 95% CI 6.4-12.1, p < 0.001) and a reduction in NEpi equivalent dose (mean difference 0.16 µg/kg/min, 95% CI 0.10-0.22, p < 0.001) between hours 0 and 3 were statistically significant. The median time to reach a MAP ≥65 was 16 minutes (IQR 5-60 min). After stratifying patients by the NED dose and number of vasopressors administered prior to the initiation of Ang-2, those with a NED dose < 0.2 µg/kg/min, NED dose < 0.3 µg/kg/min, or those on ≤ 3 vasopressors had a significantly greater reduction in NED by hour 3 than those patients above these thresholds.

CONCLUSION

Ang-2 is an effective vasopressor and reduces catecholamine dose significantly. Its effect is rapid, with target MAP obtained within 30 minutes in most patients. Given the critical importance of adequate blood pressure to organ perfusion, Ang-2 should be considered when target MAP cannot be achieved with conventional vasopressors. Ang-2 should be utilized early in the course of shock, before the NED dose exceeds 0.2-0.3 µg/kg/min and before the initiation of the fourth-line vasopressor.

Beyond the bundle: Clinical controversies in the management of sepsis in emergency medicine patients

Sepsis is a condition characterized by life-threatening organ dysfunction caused by a dysregulated host response to infection. The emergency department (ED) serves as a crucial entry point for patients presenting with sepsis. Given the heterogeneous presentation and high mortality rate associated with sepsis and septic shock, several clinical controversies have emerged in the management of sepsis. These include the use of novel therapeutic agents like angiotensin II, hydrocortisone, ascorbic acid, thiamine ("HAT") therapy, and levosimendan, Additionally, controversies with current treatments in vasopressor dosing, and the use of and balanced or unbalanced crystalloid are crucial to consider. The purpose of this review is to discuss clinical controversies in the management of septic patients, including the use of novel medications and dosing strategies, to assist providers in appropriately determining what treatment strategy is best suited for patients.

Dysregulation of the renin-angiotensin system in septic shock: Mechanistic insights and application of angiotensin II in clinical management

Synergistic physiologic mechanisms involving the renin-angiotensin system (RAS), the sympathetic nervous system, and the arginine-vasopressin system play an integral role in blood pressure homeostasis. A subset of patients with sepsis experience septic shock with attendant circulatory, cellular, and metabolic abnormalities. Septic shock is associated with increased mortality because of an inadequacy to maintain mean arterial blood pressure (MAP) despite volume resuscitation and the use of vasopressors. Vasodilatory shock raises the dose of vasopressors required to maintain a MAP of > 65 mm Hg. The diminished response to endogenous angiotensin II in sepsis-induced vasoplegia may be related to the aberrant RAS activation that stimulates a proinflammatory beneficial antibacterial response, increasing the secretion of proinflammatory cytokines that downregulate AT-1 receptors expression. Moreover, excessive systemic upregulation of nitric oxide synthase, stimulation of prostaglandin synthesis, and activation of ATP-sensitive potassium channels followed by reduced vascular entry of calcium ions are putative mechanisms in the reduced responsiveness to vasopressors. However, intravenous angiotensin II in catecholamine-resistant septic shock patients showed substantial evidence of raising the MAP to target hemodynamic levels, thus allowing time to treat underlying conditions. Nevertheless, evidence of catecholamine-sparing effect by adding angiotensin II, aimed at increasing the therapeutic index of vasopressor therapy, does not show an attenuation of end-organ damage. The use of angiotensin II in septic shock has not been evaluated in patients who are not catecholamine resistant. This, in conjunction with an evolving definition of catecholamine resistance, provides an opportunity for further evaluation of exogenous angiotensin II in septic shock.

Angiotensin II: A Review of Current Literature

Up to one-third of all patients admitted to intensive care units carry a diagnosis of shock. The use of angiotensin II is becoming widespread in all forms of shock, including cardiogenic, after the U.S. Food and Drug Administration's (FDA's) initial approval for vasoplegic shock in 2017. Here, the authors review the literature on angiotensin II's mechanism of action, benefits, and future therapeutic opportunities.

Renin-Angiotensin-Aldosterone System and Immunomodulation: A State-of-the-Art Review

The renin–angiotensin system (RAS) has long been described in the field of cardiovascular physiology as the main player in blood pressure homeostasis. However, other effects have since been described, and include proliferation, fibrosis, and inflammation. To illustrate the immunomodulatory properties of the RAS, we chose three distinct fields in which RAS may play a critical role and be the subject of specific treatments. In oncology, RAS hyperactivation has been associated with tumor migration, survival, cell proliferation, and angiogenesis; preliminary data showed promise of the benefit of RAS blockers in patients treated for certain types of cancer. In intensive care medicine, vasoplegic shock has been associated with severe macro- and microcirculatory imbalance. A relative insufficiency in angiotensin II (AngII) was associated to lethal outcomes and synthetic AngII has been suggested as a specific treatment in these cases. Finally, in solid organ transplantation, both AngI and AngII have been associated with increased rejection events, with a regional specificity in the RAS activity. These elements emphasize the complexity of the direct and indirect interactions of RAS with immunomodulatory pathways and warrant further research in the field.

LP2, the first lanthipeptide GPCR agonist in a human pharmacokinetics and safety study

Introduction of a lanthionine into a peptide may enhance target affinity, target specificity and proteolytic resistance. This manuscript reports preclinical safety studies and the first-in-human study with the lanthipeptide AT₂R agonist LP2, a structural analog of cAng-(1-7), whose N-terminus was protected against aminopeptidases by the presence of a d-lysine. None of the preclinical studies, including an in vitro multitarget panel, behavioral, respiratory and cardiovascular measurements, genotoxicity and toxicity studies in rat and dog, posed any safety concern. Due to lack of toxicity the maximum tolerated dose was not reached neither in rat nor in dog. In the human dose escalation study, healthy male volunteers received a single 1 mL subcutaneous injection (0.001 mg, 0.01 mg or 0.1 mg) of LP2 or matching placebo. In contrast to angiotensin II which has a T_1/2 in plasma of < 1 min, LP2 has a T_1/2 of approximately 2.1-2.6 hours. The fraction of the dose excreted unchanged in urine ranged from 84.73 ± 10.4 % at a dose of 0.001 mg to 66.4 ± 3.9 % at 0.1 mg. There were no deaths, serious adverse events or subject withdrawals as a result of an adverse event. The incidence of adverse events was 16.7 %; each was mild in severity. One adverse event, peripheral coldness, was considered to be possibly related to LP2 at 0.001 mg LP2. None of the results was considered to pose a clinically relevant safety concern. This study supports the potential for the therapeutic use of lanthipeptides.

Another Role for Angiotensin II?: Vasopressin-Refractory Shock After Pheochromocytoma Resection: A Case Report

A patient presented with multiple unrelated tumors and was found to have a small but functional adrenal pheochromocytoma. After pheochromocytoma resection, shock developed unresponsive to vasopressin in recommended doses (0.04 U/min infusion plus repeated 1-U boluses) but responded dramatically to an angiotensin II infusion (20 ng/kg/min) with a mean arterial pressure >100 mm Hg. The patient's blood pressure was maintained for 42 hours postoperatively with an infusion rate that ranged from 2 to 38 ng/kg/min. Because vasopressin may not always be effective for postresection shock in people with pheochromocytomas, angiotensin II may prove to be an effective alternative.

The emerging role of cell senescence in atherosclerosis

Cell senescence is a fundamental mechanism of aging and appears to play vital roles in the onset and prognosis of cardiovascular disease, fibrotic pulmonary disease, liver disease and tumor. Moreover, an increasing body of evidence shows that cell senescence plays an indispensable role in the formation and development of atherosclerosis. Multiple senescent cell types are associated with atherosclerosis, senescent human vascular endothelial cells participated in atherosclerosis via regulating the level of endothelin-1 (ET-1), nitric oxide (NO), angiotensin II and monocyte chemoattractant protein-1 (MCP-1), senescent human vascular smooth muscle cells-mediated plaque instability and vascular calcification via regulating the expression level of BMP-2, OPN, Runx-2 and inflammatory molecules, and senescent macrophages impaired cholesterol efflux and promoted the development of senescent-related cardiovascular diseases. This review summarizes the characteristics of cell senescence and updates the molecular mechanisms underlying cell senescence. Moreover, we also discuss the recent advances on the molecular mechanisms that can potentially regulate the development and progression of atherosclerosis.

Roles of angiotensin II as vasopressor in vasodilatory shock

Shock is an acute condition of circulatory failure resulting in life-threatening organ dysfunction, high morbidity and high mortality. Current management includes fluid and catecholamine therapy to maintain adequate mean arterial pressure and organ perfusion. Norepinephrine is recommended as first-line vasopressor, but other agents are available. Angiotensin II is an alternative potent vasoconstrictor without chronotropic or inotropic properties. Several studies, including a large randomized controlled trial have demonstrated its ability to increase blood pressure with catecholamine-sparing effects. Angiotensin II was consequently approved by the US FDA in 2017 and the EU in 2019 as an add-on vasopressor in vasodilatory shock. This review aims to discuss its basic pharmacology, clinical efficacy, safety and future perspectives.

Vasopressor Therapy and Blood Pressure Management in the Setting of Acute Kidney Injury

Acute kidney injury (AKI) is common in the setting of shock. Hemodynamic instability is a risk factor for the development of AKI, and pathophysiological mechanisms include loss of renal perfusion pressure and impaired microcirculation. Although restoration of mean arterial pressure (MAP) may mitigate the risk of AKI to some extent, evidence on this is conflicting. Also debatable is the optimal blood pressure needed to minimize the risk of kidney injury. A MAP of 65 mm Hg traditionally has been considered adequate to maintain renal perfusion pressure, and studies have failed to consistently show improved outcomes at higher levels of MAP. Therapeutic options to support renal perfusion consist of catecholamines, vasopressin, and angiotensin II. Although catecholamines are the most studied, they are associated with adverse events at higher doses, including AKI. Vasopressin and angiotensin II are noncatecholamine options to support blood pressure and may improve microcirculatory hemodynamics through unique mechanisms, including differential vasoconstriction of efferent and afferent arterioles within the nephron. Future areas of study include methods by which clinicians can measure renal blood flow in a macrocirculatory and microcirculatory way, a personalized approach to blood pressure management in septic shock using patient-specific measures of perfusion adequacy, and novel agents that may improve the microcirculation within the kidneys without causing adverse microcirculatory effects in other organs.

Vasopressor and Inotrope Therapy in Cardiac Critical Care

Patients admitted to the cardiac intensive care unit (CICU) are often in shock and require hemodynamic support. Identifying and addressing the pathophysiology mechanisms operating in an individual patient is crucial to achieving a successful outcome, while initiating circulatory support therapy to restore adequate tissue perfusion. Vasopressors and inotropes are the cornerstone of supportive medical therapy for shock, in addition to fluid resuscitation when indicated. Timely initiation of optimal vasopressor and inotrope therapy is essential for patients with shock, with the ultimate goals of restoring effective tissue perfusion in order to normalize cellular metabolism. Use of vasoactive agents for hemodynamic support of patients with shock should take both arterial pressure and tissue perfusion into account when choosing therapeutic interventions. For most patients with shock, including cardiogenic or septic shock, norepinephrine (NE) is an appropriate choice as a first-line vasopressor titrated to achieve an adequate arterial pressure due to a lower risk of adverse events than other catecholamine vasopressors. If tissue and organ perfusion remain inadequate, an inotrope such as dobutamine may be added to increase cardiac output to a sufficient level that meets tissue demand. Low doses of epinephrine or dopamine may be used for inotropic support, but high doses of these drugs carry an excessive risk of adverse events when used for vasopressor support and should be avoided. When NE alone is inadequate to achieve an adequate arterial pressure, addition of a noncatecholamine vasopressor such as vasopressin or angiotensin-II is reasonable, in addition to rescue therapies that may improve vasopressor responsiveness. In this review, we discuss the pharmacology and evidence-based use of vasopressor and inotrope drugs in critically ill patients, with a focus on the CICU population.

Angiotensin II and Vasopressin for Vasodilatory Shock: A Critical Appraisal of Catecholamine-Sparing Strategies

Vasodilatory shock is a serious medical condition that increases the morbidity and mortality of perioperative and critically ill patients. Norepinephrine is an established first-line therapy for this condition, but at high doses, it may lead to diminishing returns. Oftentimes, secondary noncatecholamine agents are required in those whose hypotension persists. Angiotensin II and vasopressin are both noncatecholamine agents available for the treatment of hypotension in vasodilatory shock. They have distinct modes of action and unique pharmacologic properties when compared to norepinephrine. Angiotensin II and vasopressin have shown promise in certain subsets of the population, such as those with acute kidney injury, high Acute Physiology and Chronic Health Evaluation II scores, or those receiving cardiac surgery. Any benefit from these drugs must be weighed against the risks, as overall mortality has not been shown to decrease mortality in the general population. The aims of this narrative review are to provide insight into the historical use of noncatecholamine vasopressors and to compare and contrast their unique modes of action, physiologic rationale for administration, efficacy, and safety profiles.

Role of angiotensin II in treatment of refractory distributive shock

OBJECTIVE

Clinical data and gaps in knowledge regarding angiotensin II (AT2), which was approved by the Food and Drug Administration in December 2017 via priority review for treatment of septic and other vasodilatory shock, is discussed.

SUMMARY

AT2 is an endogenous peptide that raises blood pressure via vasoconstriction and increased aldosterone release. It was previously available but withdrawn from the US market; previous low-quality research describes increases in mean arterial pressure (MAP). The recent approval of AT2 was based on data from a Phase III randomized trial comparing i.v. AT2 (n = 163) with placebo use (n = 158) in patients with vasodilatory shock receiving high doses of other vasopressors. AT2 significantly increased achievement of the primary endpoint, MAP response at 3 hours after the start of infusion, relative to placebo use (69.9% [n = 114] versus 23.4% [n = 37], p < 0.0001). Serious adverse events occurred in 60.7% (n = 99) and 67.1% (n = 106) of patients treated with AT2 and placebo recipients, respectively, including venous and arterial thromboembolic events (12.9% [n = 21] and 5.1% [n = 8], respectively). No significant effects of AT2 on 7- or 28-day mortality were seen among all patients in the ATHOS-3 trial. However, post hoc analyses suggested that AT2 may reduce mortality in patients with low baseline AT2 levels, exaggerated response to AT2, and acute kidney injury receiving concomitant renal replacement therapy. Overall, due to shortcomings of the ATHOS-3 trial data and the absence of confirmatory studies, the optimal place in therapy of AT2 for vasodilatory shock cannot be determined with confidence.

CONCLUSION

Intravenous AT2 represents a novel treatment strategy for refractory septic or other vasodilatory shock, although findings of safety and efficacy have not been replicated and the drug's optimal place in therapy is uncertain.

Adrenergic Downregulation in Critical Care: Molecular Mechanisms and Therapeutic Evidence

Catecholamines remain the mainstay of therapy for acute cardiovascular dysfunction. However, adrenergic receptors quickly undergo desensitization and downregulation after prolonged stimulation. Moreover, prolonged exposure to high circulating catecholamines levels is associated with several adverse effects on different organ systems. Unfortunately, in critically ill patients, adrenergic downregulation translates into progressive reduction of cardiovascular response to exogenous catecholamine administration, leading to refractory shock. Accordingly, there has been a growing interest in recent years toward use of noncatecholaminergic inotropes and vasopressors. Several studies investigating a wide variety of catecholamine-sparing strategies (eg, levosimendan, vasopressin, β-blockers, steroids, and use of mechanical circulatory support) have been published recently. Use of these agents was associated with improvement in hemodynamics and decreased catecholamine use but without a clear beneficial effect on major clinical outcomes. Accordingly, additional research is needed to define the optimal management of catecholamine-resistant shock.

A Retrospective Review of Angiotensin II Use in Adult Patients With Refractory Distributive Shock

PURPOSE

Catecholamines are first-line vasopressors for hemodynamic support in distributive shock but are associated with adverse effects, which may be mitigated with noncatecholamine vasopressors. Angiotensin II (ATII) is a noncatecholamine vasopressor recently approved for the management of distributive shock, but limited data support its clinical utility. The purpose of this study was to describe our institution's usage of ATII including patient outcomes (eg, response to therapy, safety profile).

MATERIALS AND METHODS

Patients who received ATII at our institution were included. Patient demographics, degree of concordance with institutional ATII use guidelines, safety profile of ATII, and response to therapy (1 and 3 hours after ATII initiation) were collected.

RESULTS

A total of 16 patients received ATII for distributive shock. The median Sequential Organ Failure Assessment score at the time of ATII initiation was 16.5 (interquartile range: 15.8-20.0). Fourteen (87.5%) patients met institutional guidelines for ATII use; 10 (62.5%) and 8 (50.0%) patients met our definition for response at 1 and 3 hours, respectively. No patients developed thrombotic or infectious complications after receiving ATII.

CONCLUSIONS

In this cohort, ATII appears to be well tolerated in patients with a high predicted mortality. Future studies evaluating the clinical efficacy of ATII are needed to determine its role in the management of distributive shock.

Synthetic Human Angiotensin II in Pediatric Patients With Vasodilatory Shock: A Report on Two Patients

Severe sepsis and septic shock continue to be an important problem in children, with hospital mortality rates for pediatric severe sepsis as high as 25%.

Successful Treatment of Antihypertensive Overdose Using Intravenous Angiotensin II

BACKGROUND

Despite multiple treatment options, antihypertensive overdose remains a cause of significant morbidity and mortality. Intravenous angiotensin II (AG II) is approved for use in vasodilatory shock. We describe 2 cases of refractory shock from antihypertensive overdose that were successfully treated using AG II.

CASE REPORTS

A 24-year-old female presented after an overdose of multiple antihypertensive medications, including an angiotensin converting enzyme inhibitor (ACEI). She developed hypotension that was refractory to norepinephrine, epinephrine, and vasopressin, with a mean arterial pressure (MAP) of 57 mm Hg 9 h after emergency department arrival. Fifteen minutes after starting AG II at 10 ng/kg/min, her heart rate and MAP rose by 7 beats/min and 12 mm Hg, respectively. Her hemodynamic parameters continued to improve thereafter. She developed acute kidney injury, which resolved prior to discharge. The second patient, a 65-year-old male, presented after an overdose of multiple antihypertensive medications, including an ACEI. Despite norepinephrine, epinephrine, and hyperinsulinemia-euglycemia, he remained bradycardic and hypotensive, with a heart rate of 47 beats/min and MAP of 59 mm Hg. Thirty minutes after starting AG II at 10 ng/kg/min, his heart rate was 61 beats/min and MAP was 66 mm Hg. He recovered without apparent sequelae. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Antihypertensive overdose can lead to shock refractory to catecholamine and vasopressin therapy. Our experience suggests that AG II is efficacious in antihypertensive overdose and may be particularly efficacious in instances of ACEI overdose. However, further study is required to confirm the appropriate indication(s).

Vasodilatory shock in the ICU and the role of angiotensin II

PURPOSE OF REVIEW

There are limited vasoactive options to utilize for patients presenting with vasodilatory shock. This review discusses vasoactive agents in vasodilatory, specifically, septic shock and focuses on angiotensin II as a novel, noncatecholamine agent and describes its efficacy, safety, and role in the armamentarium of vasoactive agents utilized in this patient population.

RECENT FINDINGS

The Angiotensin II for the Treatment of High-Output Shock 3 study evaluated angiotensin II use in patients with high-output, vasodilatory shock and demonstrated reduced background catecholamine doses and improved ability to achieve blood pressure goals associated with the use of angiotensin II. A subsequent analysis showed that patients with a higher severity of illness and relative deficiency of intrinsic angiotensin II and who received angiotensin II had improved mortality rates. In addition, a systematic review showed infrequent adverse reactions with angiotensin II demonstrating its safety for use in patients with vasodilatory shock.

SUMMARY

With the approval and release of angiotensin II, a new vasoactive agent is now available to utilize in these patients. Overall, the treatment for vasodilatory shock should not be a one-size fits all approach and should be individualized to each patient. A multimodal approach, integrating angiotensin II as a noncatecholamine option should be considered for patients presenting with this disease state.

Noteworthy Literature in 2018 for Cardiovascular Anesthesiologists and Intensivists

In this article, we present the annual review of the literature relevant for the practice of cardiovascular critical care.

Angiotensin II in septic shock

Septic shock is a life threatening condition and a medical emergency. It is associated with organ dysfunction and hypotension despite optimal volume resuscitation. Refractory septic shock carries a very high rate of mortality and is associated with ischemic and arrhythmogenic complications from high dose vasopressors. Angiotensin II (AT-II) is a product of the renin-angiotensin-aldosterone system. It is a vasopressor agent that has been recently approved by FDA to be used in conjunction with other vasopressors (catecholamines) in refractory shock and to reduce catecholamine requirements. We have reviewed the physiology and current literature on AT-II in refractory septic/vasodilatory shock. Larger trials with longer duration of follow-up are warranted to address the questions which are unanswered by the ATHOS-3 trial, especially pertaining to its effects on lungs, brain, microcirculation, inflammation, and venous thromboembolism risk.

Vasoactive Agent Use in Septic Shock: Beyond First-Line Recommendations

Septic shock is a life-threatening disorder associated with high mortality rates requiring rapid identification and intervention. Vasoactive agents are often required to maintain goal hemodynamics and preserve tissue perfusion. However, guidance regarding the proper administration of adjunct agents for the management of septic shock is limited in patients who are refractory to norepinephrine. This review summarizes vasopressor agents and describes the nuanced application of these agents in patients with septic shock, specifically focusing on clinical scenarios with limited guidance including patients who are nonresponsive to first-line agents and individuals with mixed shock states, tachyarrhythmias, obesity, valvular abnormalities, or other comorbid conditions.

FDA Approval of Angiotensin II for the Treatment of Hypotension in Adults with Distributive Shock

Distributive shock is a subset of shock marked by decreased systemic vascular resistance, organ hypoperfusion and altered oxygen extraction. Despite the use of intravenous fluids and either higher dose of catecholamines or other additional exogenous vasopressors to maintain blood pressure in the target range, the rate of mortality remains higher in patients with septic shock. Therefore, there is clearly an unmet need for additional safe and effective treatments. The use of angiotensin II to raise the mean arterial pressure (MAP) could provide additional therapy and the opportunity to evaluate a catecholamine-sparing effect by decreasing the dose of concomitant catecholamines while maintaining a target MAP. ATHOS-3 (Angiotensin II for the Treatment of High-Output Shock phase 3; ClinicalTrials.gov number, NCT02338843) was an adequate and well-controlled trial. The primary endpoint was the rate of MAP response at hour 3 of treatment with study drug, defined as either a 10-mmHg increase from baseline in MAP or a MAP of at least 75 mmHg. The secondary endpoints were changes from baseline in Sequential Organ Failure Assessment (SOFA) scores (total and cardiovascular). Mortality was an exploratory endpoint. The trial provided substantial evidence of the effectiveness of angiotensin II in raising blood pressure over placebo in patients with distributive shock, while keeping catecholamine levels constant. There was no change in the secondary endpoint of total SOFA scores relative to placebo when catecholamine use was reduced in lieu of angiotensin II treatment. There was a slight decrease in the secondary endpoint of cardiovascular SOFA score relative to placebo during the catecholamine-sparing phase, reflecting the catecholamine-sparing effect. There was a consistent trend in decreased mortality relative to placebo over the 28-day study period. Based on the agreements emanating from the special protocol assessment to assess blood pressure effects, the data from this single study supported approval of angiotensin II by the Food and Drug Administration for marketing in the USA.

Angiotensin II in Vasodilatory Shock

The Angiotensin II for the Treatment of Vasodilatory Shock (ATHOS-3) trial demonstrated the vasopressor effects and catecholamine-sparing properties of angiotensin II. As a result, the Food and Drug Administration has approved angiotensin II for the treatment of vasodilatory shock. This review details the goals of treatment of vasodilatory shock in addition to the history, current use, and recent research regarding the use of angiotensin II. An illustrative case of the use of angiotensin II is also incorporated for understanding the clinical utility of the drug.

When All Else Fails: Novel Use of Angiotensin II for Vasodilatory Shock: A Case Report

Angiotensin (AT) II is an endogenous hormone that acts on venous and arterial smooth muscle to cause vasoconstriction. Recent trials have sparked great interest in its ability to be used as a vasopressor for catecholamine-refractory hypotension. Herein, we describe the successful use of AT II in a patient with a colonic perforation with septic shock refractory to conventional treatment. After AT II initiation, there was an immediate reduction in catecholamine requirement, and the patient survived.

Angiotensin II: a new therapeutic option for vasodilatory shock

Angiotensin II (Ang II), part of the renin-angiotensin-aldosterone system (RAS), is a potent vasoconstrictor and has been recently approved for use by the US Food and Drug Administration in high-output shock. Though not a new drug, the recently published Angiotensin II for the Treatment of High Output Shock (ATHOS-3) trial, as well as a number of retrospective analyses have sparked renewed interest in the use of Ang II, which may have a role in treating refractory shock. We describe refractory shock, the unique mechanism of action of Ang II, RAS dysregulation in shock, and the evidence supporting the use of Ang II to restore blood pressure. Evidence suggests that Ang II may preferentially be of benefit in acute kidney injury and acute respiratory distress syndrome, where the RAS is known to be disrupted. Additionally, there may be a role for Ang II in cardiogenic shock, angiotensin converting enzyme inhibitor overdose, cardiac arrest, liver failure, and in settings of extracorporeal circulation.

Angiotensin II

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A Blast From the Past: Revival of Angiotensin II for Vasodilatory Shock

OBJECTIVE

To review and summarize data on angiotensin II (AT-II), approved by the Food and Drug Administration (FDA) in December 2017 to increase blood pressure in adults with septic or other distributive shock.

DATA SOURCES

A PubMed/MEDLINE search was conducted using the following terms: (angiotensin ii OR angiotensin 2) AND (shock) from 1966 to February 2018.

STUDY SELECTION AND DATA EXTRACTION

A total of 691 citations were reviewed with only relevant clinical data extracted.

DATA SYNTHESIS

AT-II is a peptide hormone with a multitude of physiological effects-namely, vasoconstriction of venous and arterial smooth muscle. The priority approval granted by the FDA was secondary to a phase 3 study of patients receiving at least 0.2 µg/kg/min of norepinephrine or equivalent for vasodilatory shock. Compared with placebo, AT-II had a significantly higher rate of response, defined as a mean arterial pressure of 75 mm Hg or an increase of 10 mm Hg. No significant difference was found in death by day 28.

CONCLUSIONS

AT-II is a newly available vasoactive agent with a novel mechanism for the treatment of distributive shock. Further research is needed to define its exact role in therapy of shock states, identify patients most likely to benefit, and further study its safety profile in critical illness.

Angiotensin in Critical Care

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2018. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2018 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901 .

The effect of angiotensin II on blood pressure in patients with circulatory shock: a structured review of the literature

BACKGROUND

Circulatory shock is a common syndrome with a high mortality and limited therapeutic options. Despite its discovery and use in clinical and experimental settings more than a half-century ago, angiotensin II (Ang II) has only been recently evaluated as a vasopressor in distributive shock. We examined existing literature for associations between Ang II and the resolution of circulatory shock.

METHODS

We searched PubMed, MEDLINE, Ovid, and Embase to identify all English literature accounts of intravenous Ang II in humans for the treatment of shock (systolic blood pressure [SBP] ≤ 90 mmHg or a mean arterial pressure [MAP] ≤ 65 mmHg), and hand-searched the references of extracted papers for further studies meeting inclusion criteria. Of 3743 articles identified, 24 studies including 353 patients met inclusion criteria. Complete data existed for 276 patients. Extracted data included study type, publication year, demographics, type of shock, dosing of Ang II or other vasoactive medications, and changes in BP, lactate, and urine output. BP effects were grouped according to type of shock, with additional analyses completed for patients with absent blood pressure. Shock was distributive (n = 225), cardiogenic (n = 38), or from other causes (n = 90). Blood pressure as absent in 18 patients.

RESULTS

For the 276 patients with complete data, MAP rose by 23.4% from 63.3 mmHg to 78.1 mmHg in response to Ang II (dose range: 15 ng/kg/min to 60 mcg/min). SBP rose by 125.2% from 56.9 mmHg to 128.2 mmHg (dose range: 0.2 mcg/min to a 1500 mcg bolus). A total of 271 patients with complete data were determined to exhibit a BP effect which was directly associated with Ang II. Subgroups (patients with cardiogenic, septic, and other types of shock) exhibited similar increases in BP. In patients with absent BP, deemed to be cardiac arrest, return of spontaneous circulation (ROSC) was achieved, and BP increased by an average of 107.3 mmHg in 11 of 18 patients. The remaining seven patients with cardiac arrest did not respond.

CONCLUSIONS

Intravenous Ang II is associated with increased BP in patients with cardiogenic, distributive, and unclassified shock. A role may exist for Ang II in restoring circulation in cardiac arrest.

Urinary Oxygenation as a Surrogate Measure of Medullary Oxygenation During Angiotensin II Therapy in Septic Acute Kidney Injury

OBJECTIVES

Angiotensin II is an emerging therapy for septic acute kidney injury, but it is unknown if its vasoconstrictor action induces renal hypoxia. We therefore examined the effects of angiotensin II on intrarenal PO2 in ovine sepsis. We also assessed the validity of urinary PO2 as a surrogate measure of medullary PO2.

DESIGN

Interventional study.

SETTING

Research Institute.

SUBJECTS

Sixteen adult Merino ewes (n = 8/group).

INTERVENTIONS

Sheep were instrumented with fiber-optic probes in the renal cortex, medulla, and within a bladder catheter to measure PO2. Conscious sheep were infused with Escherichia coli for 32 hours. At 24-30 hours, angiotensin II (0.5-33.0 ng/kg/min) or saline vehicle was infused.

MEASUREMENTS AND MAIN RESULTS

Septic acute kidney injury was characterized by hypotension and a 60% ± 6% decrease in creatinine clearance. During sepsis, medullary PO2 decreased from 36 ± 1 to 30 ± 3 mm Hg after 1 hour and to 20 ± 2 mm Hg after 24 hours; at these times, urinary PO2 was 42 ± 2, 34 ± 2, and 23 ± 2 mm Hg. Increases in urinary neutrophil gelatinase-associated lipocalin (12% ± 3%) and serum creatinine (60% ± 23%) were only detected at 8 and 24 hours, respectively. IV infusion of angiotensin II, at 24 hours of sepsis, restored arterial pressure and improved creatinine clearance, while not exacerbating medullary or urinary hypoxia.

CONCLUSIONS

In septic acute kidney injury, renal medullary and urinary hypoxia developed several hours before increases in currently used biomarkers. Angiotensin II transiently improved renal function without worsening medullary hypoxia. In septic acute kidney injury, angiotensin II appears to be a safe, effective therapy, and urinary PO2 may be used to detect medullary hypoxia.