Safe Use of Vasopressin and Angiotensin II for Patients with Circulatory Shock

Adjunctive Vasopressors in Patients with Septic Shock: Protocol for a Systematic Review and Meta-Analysis

Background

Over one-third of patients with septic shock have adjunctive vasopressors added to first-line vasopressors. However, no randomized trial has detected improved mortality with adjunctive vasopressors. Published systematic reviews and meta-analysis have sought to inform the use of adjunctive vasopressors, yet each published review has limitations that hinder its interpretation. This review aims to overcome the limitations of previous reviews by systematically synthesizing the direct evidence for adjunctive vasopressor therapy use in adult patients with septic shock.

Methods

We will conduct a systematic review and meta-analysis of randomized controlled trials evaluating adjunctive vasopressors (vasopressin analogues, angiotensin II, hydroxocobalamin, methylene blue, and catecholamine analogues) in adult patients with septic shock. Relevant studies will be identified through comprehensive searches of MEDLINE, Embase, CENTRAL, and reference lists of previous systematic reviews. Only randomized trials comparing adjunctive vasopressors (>75% of subjects on vasopressors at enrollment) to standard care vasopressors in adults with septic shock (>75% of subjects having septic shock) will be included. Titles and abstracts will be screened, full-text articles assessed for eligibility, and data extracted from included studies. Outcomes of interest include short-term mortality, intermediate-term mortality, kidney replacement therapy, digital/peripheral ischemia, and venous thromboembolism. Pairwise meta-analysis using a random-effects model will be utilized to estimate the risk ratio for the outcomes. Risk of bias will be adjudicated with the Cochrane Risk of Bias 2 tool, and GRADE will be used to rate the certainty of the body of evidence.

Discussion

Although adjunctive vasopressors are commonly used in patients with septic shock their effect on patient-important outcomes is unclear. This study is planned to use rigorous systematic review methodology, including strict adhere to established guidelines, in order to overcome limitations of previously-published reviews and inform clinical practice and treatment guidelines for the use of adjunctive vasopressors in adults with septic shock.

Systematic review registration

PROSPERO CRD4202327984.

Echocardiographic profiles and hemodynamic response after vasopressin initiation in septic shock: A cross-sectional study

PURPOSE

Vasopressin, used as a catecholamine adjunct, is a vasoconstrictor that may be detrimental in some hemodynamic profiles, particularly left ventricular (LV) systolic dysfunction. This study tested the hypothesis that echocardiographic parameters differ between patients with a hemodynamic response after vasopressin initiation and those without a response.

METHODS

This retrospective, single-center, cross-sectional study included adults with septic shock receiving catecholamines and vasopressin with an echocardiogram performed after shock onset but before vasopressin initiation. Patients were grouped by hemodynamic response, defined as decreased catecholamine dosage with mean arterial pressure ≥ 65 mmHg six hours after vasopressin initiation, with echocardiographic parameters compared. LV systolic dysfunction was defined as LV ejection fraction (LVEF) <45%.

RESULTS

Of 129 included patients, 72 (56%) were hemodynamic responders. Hemodynamic responders, versus non-responders, had higher LVEF (61% [55%,68%] vs. 55% [40%,65%]; p = 0.02) and less-frequent LV systolic dysfunction (absolute difference  -16%; 95% CI -30%,-2%). Higher LVEF was associated with higher odds of hemodynamic response (for each LVEF 10%, response OR 1.32; 95% CI 1.04-1.68). Patients with LV systolic dysfunction, versus without LV systolic dysfunction, had higher mortality risk (HR(t) = e^[0.81-0.1*t]; at t = 0, HR 2.24; 95% CI 1.08-4.64).

CONCLUSIONS

Pre-drug echocardiographic profiles differed in hemodynamic responders after vasopressin initiation versus non-responders.

Vasoplegic syndrome in patients undergoing heart transplantation

Objectives

To summarize the risk factors, onset time, and treatment of vasoplegic syndrome in patients undergoing heart transplantation.

Methods

The PubMed, OVID, CNKI, VIP, and WANFANG databases were searched using the terms "vasoplegic syndrome," "vasoplegia," "vasodilatory shock," and "heart transplant*," to identify eligible studies. Data on patient characteristics, vasoplegic syndrome manifestation, perioperative management, and clinical outcomes were extracted and analyzed.

Results

Nine studies enrolling 12 patients (aged from 7 to 69 years) were included. Nine (75%) patients had nonischemic cardiomyopathy, and three (25%) patients had ischemic cardiomyopathy. The onset time of vasoplegic syndrome varied from intraoperatively to 2 weeks postoperatively. Nine (75%) patients developed various complications. All patients were insensitive to vasoactive agents.

Conclusions

Vasoplegic syndrome can occur at any time during the perioperative period of heart tranplantation, especially after the discontinuation of bypass. Methylene blue, angiotensin II, ascorbic acid, and hydroxocobalamin have been used to treat refractory vasoplegic syndrome.

Updates in the Management of Perioperative Vasoplegic Syndrome

Vasoplegic syndrome occurs relatively frequently in cardiac surgery, liver transplant, major noncardiac surgery, in post-return of spontaneous circulation situations, and in pateints with sepsis. It is paramount for the anesthesiologist to understand both the pathophysiology of vasoplegia and the different treatment strategies available for rescuing a patient from life-threatening hypotension.

Catecholamine-Sparing Effect of Angiotensin II in an Anephric Patient With Mixed Shock After Cardiac Revascularization Surgery: A Case Report

Vasodilatory shock is common following cardiac surgery, caused by an inflammatory response to cardiopulmonary bypass (CPB). Some cases are refractory to volume resuscitation, high-dose catecholamines, arginine vasopressin, and established adjunctive therapies. Angiotensin II (ANG-2), an endogenous hormone in the renin-angiotensin-aldosterone system (RAAS), has several direct and indirect vasoconstrictive properties that make it a promising potential treatment. This case describes the successful use of ANG-2 in an anephric patient who suffered from severe refractory shock following CPB, offering a unique potential mechanism of benefit in a broader population of patients with baseline impaired RAAS.

Preadmission Antihypertensive Drug Use and Sepsis Outcome: Impact of Angiotensin-Converting Enzyme Inhibitors (ACEIs) and Angiotensin Receptor Blockers (ARBs)

BACKGROUND

Several studies have reported improved sepsis outcomes when certain preadmission antihypertensive drugs, namely, calcium channel blockers (CCBs), are used. This study aims to determine whether preadmission antihypertensive drug use, especially angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), is associated with decreased total hospital mortality in sepsis.

METHODS

This study was conducted using the unique database of a sepsis cohort from the National Health Insurance Research Database in Taiwan. Frequency matching for age and sex between preadmission antihypertensive drug users (study cohort) and nonusers (comparison cohort) was conducted. The primary outcome was total hospital mortality. Logistic regression analyses were performed to calculate the odds ratios (ORs) of important variables. Further joint effect analyses were carried out to examine the impacts of different combinations of antihypertensive drugs.

RESULTS

A total of 33,213 sepsis antihypertensive drug use patients were retrieved as the study cohort, and an equal number of matched sepsis patients who did not use antihypertensive drugs were identified as the comparison cohort. The study cohort had a higher incidence rate of being diagnosed with septic shock compared with the comparison cohort (4.36%-2.31%, P < 0.001) and a higher rate of total hospital mortality (38.42%-24.57%, P < 0.001). In the septic shock condition, preadmission antihypertensive drug use was associated with a decreased adjusted OR (OR = 0.66, 95% confidence interval [CI], 0.55-0.80) for total hospital mortality, which was not observed for the nonseptic shock condition. Compared with antihypertensive drug nonusers, both ACEI and ARB users had decreased adjusted ORs for total hospital mortality in sepsis (adjusted OR = 0.93, 95% CI, 0.88-0.98 and adjusted OR = 0.85, 95% CI, 0.81-0.90); however, CCB, beta-blocker, and diuretic users did not. In the septic shock condition, ACEI, ARB, CCB, and beta-blocker users all had decreased ORs for total hospital mortality. Joint effect analysis showed ACEI use, except in combination with diuretics, to be associated with a decreased adjusted OR for total hospital mortality in sepsis. Similar results were observed for ARB users.

CONCLUSIONS

Preadmission ACEI or ARB use is associated with a decreased risk of total hospital mortality, regardless of a nonshock or septic shock condition.

Hemodynamic Response to Vasopressin Dosage of 0.03 Units/Min vs. 0.04 Units/Min in Patients With Septic Shock

BACKGROUND

Arginine vasopressin (AVP) is suggested as an adjunct to norepinephrine in patients with septic shock. Guidelines recommend an AVP dosage up to 0.03 units/min, but 0.04 units/min is commonly used in practice based on initial studies. This study was designed to compare the incidence of hemodynamic response between initial fixed-dosage AVP 0.03 units/min and AVP 0.04 units/min.

METHODS

This retrospective, multi-hospital health system, cohort study included adult patients with septic shock receiving AVP as an adjunct to catecholamine vasopressors. Patients were excluded if they received an initial dosage other than 0.03 units/min or 0.04 units/min, or AVP was titrated within the first 6 hours of therapy. The primary outcome was hemodynamic response, defined as a mean arterial pressure ≥65 mm Hg and a decrease in catecholamine dosage at 6 hours after AVP initiation. Inverse probability of treatment weighting (IPTW) based on the propensity score for initial AVP dosage receipt was utilized to estimate adjusted exposure effects.

RESULTS

Of the 1536 patients included in the observed data, there was a nearly even split between initial AVP dosage of 0.03 units/min (n = 842 [54.8%]) and 0.04 units/min (n = 694 [45.2%]). Observed patients receiving AVP 0.03 units/min were more frequently treated at the main campus academic medical center (96.3% vs. 52.2%, p < 0.01) and in a medical intensive care unit (87.4% vs. 39.8%, p < 0.01). The IPTW analysis included 1379 patients with achievement of baseline covariate balance. There was no evidence for a difference between groups in the incidence of hemodynamic response (0.03 units/min 50.0% vs. 0.04 units/min 53.1%, adjusted relative risk 1.06 [95% CI 0.94, 1.20]).

CONCLUSIONS

Initial AVP dosing varied by hospital and unit type. Although commonly used, an initial AVP dosage of 0.04 units/min was not associated with a higher incidence of early hemodynamic response to AVP in patients with septic shock.

Angiotensin II Infusion for Shock: A Multicenter Study of Postmarketing Use

BACKGROUND

Vasodilatory shock refractory to catecholamine vasopressors and arginine vasopressin is highly morbid and responsible for significant mortality. Synthetic angiotensin II is a potent vasoconstrictor that may be suitable for use in these patients.

RESEARCH QUESTION

What is the safety and effectiveness of angiotensin II and what variables are associated with a favorable hemodynamic response?

STUDY DESIGN AND METHODS

We performed a multicenter, retrospective study at five tertiary medical centers in the United States. The primary end point of hemodynamic responsiveness to angiotensin II was defined as attainment of mean arterial pressure (MAP) of ≥ 65 mm Hg with a stable or reduced total vasopressor dosage 3 h after drug initiation.

RESULTS

Of 270 included patients, 181 (67%) demonstrated hemodynamic responsiveness to angiotensin II. Responders showed a greater increase in MAP (+10.3 mm Hg vs +1.6 mm Hg, P < .001) and reduction in vasopressor dosage (-0.20 μg/kg/min vs +0.04 μg/kg/min; P < .001) compared with nonresponders at 3 h. Variables associated with favorable hemodynamic response included lower lactate concentration (OR 1.11; 95% CI, 1.05-1.17, P < .001) and receipt of vasopressin (OR, 6.05; 95% CI, 1.98-18.6; P = .002). In severity-adjusted multivariate analysis, hemodynamic responsiveness to angiotensin II was associated with reduced likelihood of 30-day mortality (hazard ratio, 0.50; 95% CI, 0.35-0.71; P < .001). Arrhythmias occurred in 28 patients (10%) and VTE was identified in 4 patients.

INTERPRETATION

In postmarketing use for vasopressor-refractory shock, 67% of angiotensin II recipients demonstrated a favorable hemodynamic response. Patients with lower lactate concentrations and those receiving vasopressin were more likely to respond to angiotensin II. Patients who responded to angiotensin II experienced reduced mortality.

Angiotensin II for Critically Ill Patients With Shock After Heart Transplant

Patients undergoing heart transplant are at high risk for vasodilatory shock in the postoperative period, due to a combination of vascular dysfunction from end-stage heart failure and inflammatory response to cardiopulmonary bypass and, increasingly, long-term exposure to nonpulsatile blood flow in those who have received a left ventricular assist device as a bridge to transplant. Patients who have this vasoplegic syndrome, which may be refractory to traditional agents used in the treatment of shock, are vulnerable to organ dysfunction and death. Angiotensin II (ANG-2) is of increasing interest as an adjunct to traditional therapy, both for improvement in blood pressure and for sparing the use of high-dose catecholamine vasopressors. This case series describes the use of ANG-2 in 4 clinical scenarios for the treatment of shock due to heart transplant surgery, supporting its use in this role and justifying further prospective studies to clarify the appropriate place for ANG-2 in the hierarchy of adjunctive therapies.

Mortality, Morbidity, and Costs After Implementation of a Vasopressin Guideline in Medical Intensive Care Patients With Septic Shock: An Interrupted Time Series Analysis

Background: Vasopressin decreases vasopressor requirements in patients with septic shock. However, the optimal norepinephrine dose for initiation or cessation of vasopressin is unclear. Objective: Analyze monthly intensive care unit (ICU) mortality rates 1 year preimplementation and postimplementation of a guideline suggesting a norepinephrine dose of 50 µg/min or more for initiation of vasopressin and early cessation of vasopressin. Methods: This retrospective quasi-experimental study included adult patients with septic shock admitted to the medical ICU of a tertiary care medical center over 2 years. Time periods were evaluated with interrupted time series analysis. Results: A total of 1148 patients were included: 573 patients preguideline and 575 patients postguideline. Group characteristics were well balanced at baseline, except patients postguideline had higher sequential organ failure assessment scores. Postguideline, fewer patients were initiated on vasopressin (305 [53.2%] vs 217 [37.7%], absolute difference -15.5% [95% CI -21.2% to -9.8%]), and the norepinephrine dose at vasopressin initiation was higher (median 25 [interquartile range 18, 40] µg/min vs 40 [22, 52] µg/min; median difference 15 [95% CI 11 to 19] µg/min; P < 0.01). After guideline implementation, there was no evidence for a difference in ICU mortality rate slope (slope change 0.07% [95% CI -0.8% to 1.0%] per month; P 0.87), but the vasoactive cost level decreased by US$183 (95% CI -US$327 to -US$39) per patient immediately after implementation. Conclusion and Relevance: Implementation of a guideline suggesting a high norepinephrine dose threshold for vasopressin initiation and early vasopressin cessation in patients with septic shock appears to be safe and may decrease vasoactive costs.

Cost-effectiveness of second-line vasopressors for the treatment of septic shock

PURPOSE

To determine the cost-effectiveness of escalating doses of norepinephrine or norepinephrine plus the adjunctive use of vasopressin or angiotensin II as a second-line vasopressor for septic shock.

MATERIALS AND METHODS

Decision tree analysis was performed to compare costs and outcomes associated with norepinephrine monotherapy or the two adjunctive second-line vasopressors. Short- and long-term outcomes modeled included ICU survival and lifetime quality-adjusted-life-years (QALY) gained. Costs were modeled from a payer's perspective, with a willingness-to-pay threshold set at $100,000/unit gained. One-way (tornado diagrams) and probabilistic sensitivity analyses were performed.

RESULTS

Adjunctive vasopressin was the most cost-effective therapy, and dominated both norepinephrine monotherapy and adjunctive angiotensin II by producing higher ICU survival at less cost. For the lifetime horizon, while norepinephrine monotherapy was least expensive, adjunctive vasopressin was the most cost-effective with an incremental cost-effectiveness ratio of $19,762 / QALY gained. Although adjunctive angiotensin II produced more QALYs compared to norepinephrine monotherapy, it was dominated in the long-term evaluation by second-line vasopressin. Sensitivity analyses demonstrated model robustness and medication costs were not significant drivers of model results.

CONCLUSIONS

Vasopressin is the most cost-effective second-line vasopressor in both the short- and long-term evaluations. Vasopressor price is a minor contributor to overall cost.

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.

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.