Postoperative Vasoplegic Syndrome Is Associated With Impaired Endothelial Vasomotor Response in Cardiac Surgery: A Prospective, Observational Study

Norepinephrine weaning guided by the Hypotension Prediction Index in vasoplegic shock after cardiac surgery: protocol for a single-centre, open-label randomised controlled trial - the NORAHPI study

INTRODUCTION

Norepinephrine (NE) is the first-line recommended vasopressor for restoring mean arterial pressure (MAP) in vasoplegic syndrome (vs) following cardiac surgery with cardiopulmonary bypass. However, solely focusing on target MAP values can lead to acute hypotension episodes during NE weaning. The Hypotension Prediction Index (HPI) is a machine learning algorithm embedded in the Acumen IQ device, capable of detecting hypotensive episodes before their clinical manifestation. This study evaluates the clinical benefits of an NE weaning strategy guided by the HPI.

MATERIAL AND ANALYSIS

The Norahpi trial is a prospective, open-label, single-centre study that randomises 142 patients. Inclusion criteria encompass adult patients scheduled for on-pump cardiac surgery with postsurgical NE administration for vs patient randomisation occurs once they achieve haemodynamic stability (MAP>65 mm Hg) for at least 4 hours on NE. Patients will be allocated to the intervention group (n=71) or the control group (n=71). In the intervention group, the NE weaning protocol is based on MAP>65 mmHg and HPI<80 and solely on MAP>65 mm Hg in the control group. Successful NE weaning is defined as achieving NE weaning within 72 hours of inclusion. An intention-to-treat analysis will be performed. The primary endpoint will compare the duration of NE administration between the two groups. The secondary endpoints will include the prevalence, frequency and time of arterial hypotensive events monitored by the Acumen IQ device. Additionally, we will assess cumulative diuresis, the total dose of NE, and the number of protocol weaning failures. We also aim to evaluate the occurrence of postoperative complications, the length of stay and all-cause mortality at 30 days.

ETHICS AND DISSEMINATION

Ethical approval has been secured from the Institutional Review Board (IRB) at the University Hospital of Amiens (IRB-ID:2023-A01058-37). The findings will be shared through peer-reviewed publications and presentations at national and international conferences.

TRIAL REGISTRATION NUMBER

NCT05922982.

Perioperative care in infective endocarditis

Patients undergoing surgery for acute infective endocarditis are among those with the highest risk. Their preoperative condition has significant impact on outcomes. There are specific issues related with the preoperative situation, intraoperative findings, and postoperative management. In this narrative review, focus is placed on the most critical aspects in the perioperative period including the management and weaning from mechanical ventilation, the management of vasoplegia, the management of the chest open, antithrombotic therapy, transfusion, coagulopathy, management of atrial fibrillation, the duration of antibiotic therapy, and pacemaker implantation.

Effect of norepinephrine on the vascular waterfall and tissue perfusion in vasoplegic hypotensive patients: a prospective, observational, applied physiology study in cardiac surgery

BACKGROUND

Norepinephrine is a commonly used drug for treating vasoplegic acute circulatory failure in ICU. The prediction of norepinephrine macro- and micro-circulatory response is complicated by its uneven receptors' distribution between the arterial and the venous structures, and by the presence of a physiological vascular waterfall (VW) that disconnects the arterial and the venous circulation in two pressure systems. The objectives of this study were to describe the VW in patients with arterial hypotension due to vasodilatory circulatory shock, and its behavior according to its response to norepinephrine infusion.

METHODS

A prospective, observational, bi-centric study has included adult patients, for whom the physician decided to initiate norepinephrine during the six first hours following admission to the ICU after cardiac surgery, and unresponsive to a fluid challenge. The mean systemic pressure (MSP) and the critical closing pressure (CCP) were measured at inclusion and after norepinephrine infusion.

RESULTS

Thirty patients were included. Norepinephrine increased arterial pressure and total peripheral resistances in all cohort. The cohort was dichotomized as VW responders (patients with a change of VW over the least significant change (≥ 93% increase in VW)), and as VW non-responders. In 19 (63%) of the 30 patients, VW increased from 3.47 [- 14.43;7.71] mmHg to 43.6 [25.8;48.1] mmHg, p < 0.001) with norepinephrine infusion, being classified as VW responders. The VW responders improved cardiac index (from 1.8 (0.6) L min-1 m-2 to 2.2 (0.5) L min-1 m-2, p = 0.002), capillary refill time (from to 4.2 (1.1) s to 3.1 (1) s, p = 0.006), and pCO2 gap (from 9 [7;10] mmHg to 6 [4;8] mmHg, p = 0.04). No baseline parameters were able to predict the VW response to norepinephrine. In comparison, VW non-responders did not significantly change the VW (from 5 [-5;16] mmHg to -2 [-12;15] mmHg, p = 0.17), cardiac index (from 1.6 (0.3) L min-1 m-2 to 1.8 (0.4) L min-1 m-2, p = 0.09) and capillary refill time (from 4.1 (1) s to 3.7 (1.4), p = 0.44).

CONCLUSIONS

In post-cardiac surgery patients with vasoplegic arterial hypotension, the vascular waterfall is low. Norepinephrine did not systematically restore the vascular waterfall. Increase of the vascular waterfall was associated with an improvement of laboratory and clinical parameters of tissue perfusion.

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.

Dynamic Arterial Elastance Is Associated With the Vascular Waterfall in Patients Treated With Norepinephrine: An Observational Study

Introduction: It has been suggested that dynamic arterial elastance (Ea_dyn) can predict decreases in arterial pressure in response to changing norepinephrine levels. The objective of this study was to determine whether Ea_dyn is correlated with determinants of the vascular waterfall [critical closing pressure (CCP) and systemic arterial resistance (SARi)] in patients treated with norepinephrine.

Materials and Methods: Patients treated with norepinephrine for vasoplegia following cardiac surgery were studied. Vascular and flow parameters were recorded immediately before the norepinephrine infusion and then again once hemodynamic parameters had been stable for 15 min. The primary outcomes were Ea_dyn and its associations with CCP and SARi. The secondary outcomes were the associations between Ea_dyn and vascular/flow parameters.

Results: At baseline, all patients were hypotensive with Ea_dyn of 0.93 [0.47;1.27]. Norepinephrine increased the arterial blood pressure, cardiac index, CCP, total peripheral resistance (TPRi), arterial elastance, and ventricular elastance and decreased Ea_dyn [0.40 (0.30;0.60)] and SARi. Ea_dyn was significantly associated with arterial compliance (C_A), CCP, and TPRi (p < 0.05).

Conclusion: In patients with vasoplegic syndrome, Ea_dyn was correlated with determinants of the vascular waterfall. Ea_dyn is an easy-to-read functional index of arterial load that can be used to assess the patient’s macro/microcirculatory status.

Clinical Trial Registration:ClinicalTrials.gov #NCT03478709.

Anaesthesia and ICU sedation with sevoflurane do not reduce myocardial injury in patients undergoing cardiac surgery: A randomized prospective study

BACKGROUND

To evaluate the effect of anaesthesia and ICU sedation with sevoflurane to protect the myocardium against ischemia-reperfusion injury associated to cardiac surgery assessed by troponin release.

METHODS

We performed a prospective, open-label, randomized study in cardiac surgery with cardiopulmonary bypass. Patients were randomized to an algorithm-based intervention group and a control group. The main outcome was the perioperative kinetic of cardiac troponin I (cTnI). The secondary outcomes included composite endpoint, GDF-15 (macrophage inhibitory cytokine-1) value, arterial lactate levels, and the length of stay (LOS) in the ICU.

RESULTS

Of 82 included patients, 81 were analyzed on an intention-to-treat basis (intervention group: n = 42; control group: n = 39). On inclusion, the intervention and control groups did not differ significantly in terms of demographic and surgical data. The postoperative kinetics of cTnI did not differ significantly between groups: the mean difference was 0.44 ± 1.09 μg/ml, P = .69. Incidence of composite endpoint and GDF-15 values were higher in the sevoflurane group than in propofol group. The intervention and control groups did not differ significantly in terms of ICU stay and hospital stay.

CONCLUSION

The use of an anaesthesia and ICU sedation with sevoflurane was not associated with a lower incidence of myocardial injury assessed by cTnI. Sevoflurane administration was associated with higher prevalence of acute renal failure and higher GDF-15 values.

The Use of Angiotensin II for the Treatment of Post-cardiopulmonary Bypass Vasoplegia

Purpose

Vasoplegia is a common complication after cardiac surgery and is related to the use of cardiopulmonary bypass (CPB). Despite its association with increased morbidity and mortality, no consensus exists in terms of its treatment. In December 2017, angiotensin II (AII) was approved by the Food and Drug Administration (FDA) for use in vasodilatory shock; however, except for the ATHOS-3 trial, its use in vasoplegic patients that underwent cardiac surgery on CPB has mainly been reported in case reports. Thus, the aim of this review is to collect all the clinically relevant data and describe the pharmacologic mechanism, efficacy, and safety of this novel pharmacologic agent for the treatment of refractory vasoplegia in this population.

Methods

Two independent reviewers performed a systematic search in PubMed, Embase, Web of Science, and Cochrane Library using relevant MeSH terms (Angiotensin II, Vasoplegia, Cardiopulmonary Bypass, Cardiac Surgical Procedures).

Results

The literature search yielded 820 unique articles. In total, 9 studies were included. Of those, 2 were randomized clinical trials (RCTs) and 6 were case reports and 1 was a retrospective cohort study.

Conclusions

AII appears to be a promising means of treatment for patients with post-operative vasoplegia. It is demonstrated to be effective in raising blood pressure, while no major adverse events have been reported. It remains uncertain whether this agent will be broadly available and whether it will be more advantageous in the clinical management of vasoplegia compared to other available vasopressors. For that reason, we should contain our eagerness and enthusiasm regarding its use until supplementary knowledge becomes available.

Electronic supplementary material

The online version of this article (10.1007/s10557-020-07098-3) contains supplementary material, which is available to authorized users.

Potential risks in using midodrine for persistent hypotension after cardiac surgery: a comparative cohort study

Background

Persistent hypotension is a frequent complication after cardiac surgery with cardiopulmonary bypass (CPB). Midodrine, an orally administered alpha agonist, could potentially reduce intravenous vasopressor use and accelerate ICU discharge of otherwise stable patients. The main objective of this study was to explore the clinical impacts of administering midodrine in patients with persistent hypotension after CPB. Our hypothesis was that midodrine would safely accelerate ICU discharge and be associated with more days free from ICU at 30 days.

Results

We performed a retrospective cohort study that included all consecutive patients having received midodrine while being on vasopressor support in the ICU within the first week after cardiac surgery with CPB, between January 2014 and January 2018 at the Montreal Heart Institute. A contemporary propensity score matched control group that included patients who presented similarly prolonged hypotension after cardiac surgery was formed.

After matching, 74 pairs of patients (1:1) fulfilled inclusion criteria for the study and control groups. Midodrine use was associated with fewer days free from ICU (25.8 [23.7–27.1] vs 27.2 [25.9–28] days, p = 0.002), higher mortality (10 (13.5%) vs 1 (1.4%), p = 0.036) and longer ICU length of stay (99 [68–146] vs 68 [48–99] hours, p = 0.001). There was no difference in length of intravenous vasopressors (63 [40–87] vs 44 [26–66] hours, p = 0.052), rate of ICU readmission (6 (8.1%) vs 2 (2.7%), p = 0.092) and occurrence of severe kidney injury (11 (14.9%) vs 10 (13.5%) patients, p = 0.462) between groups.

Conclusion

The administration of midodrine for sustained hypotension after cardiac surgery with CPB was associated with fewer days free from ICU and higher mortality. Routine prescription of midodrine to hasten ICU discharge after cardiac surgery should be used with caution until further prospective studies are conducted.

Vasoplegic syndrome in cardiac surgery: Definitions, pathophysiology, diagnostic approach and management

Vasoplegic syndrome is a state of vasopressor resistant systemic vasodilation in the presence of a normal cardiac output. Its definition, pathophysiology, risk factors, diagnosis and therapeutic approach will be reviewed in this paper. It occurs frequently during cardiac surgery and is associated with high morbidity and mortality. A search in the LILACS, MEDLINE, and GOOGLE SCHOLAR databases was conducted to find the most relevant papers during the last 18 years. Prompt identification and diagnosis of patients at risk must be undertaken in order to implement an optimal therapeutic approach. This latter includes early treatment with vasopressors with different mechanisms of action.