Neuroendocrine predictors of vasoplegia after cardiopulmonary bypass

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.

Vasoplegic Syndrome in Cardiac Surgery: A Narrative Review of Etiologic Mechanisms and Therapeutic Options

Vasoplegic syndrome, a form of distributive shock that may manifest during or after cardiopulmonary bypass, is a serious complication that increases morbidity and mortality after cardiac surgery. No consensus definition exists, but vasoplegic syndrome is generally described as a state of pathologic vasodilation causing hypotension refractory to fluid resuscitation and vasopressor therapy, and resulting in organ malperfusion despite a normal or increased cardiac output. Diagnosis can be complex as there is a broad differential diagnosis for low systemic vascular resistance in the cardiac surgical patient. Interpretation of hemodynamic data can also be challenging in the setting of mixed shock states and mechanical support. This narrative review summarizes the pathophysiology of vasoplegic syndrome, the literature concerning its incidence and risk factors, the hemodynamic parameters important to the diagnosis of vasoplegic syndrome, a consensus definition of the syndrome, and a proposed goal-directed treatment framework.

Vasoplegia in Cardiac Surgery: A Systematic Review and Meta-analysis of Current Definitions and Their Influence on Clinical Outcomes

OBJECTIVES

To identify differences in the reported vasoplegia incidence, intensive care unit (ICU) length of stay (LOS), and 30-day mortality rates as influenced by different vasoplegia definitions used in cardiac surgery studies.

DESIGN

A systematic review was performed covering the period 1977 to 2023 using PubMed/MEDLINE, Embase, Web of Science, Cochrane Library, and Emcare and a meta-analysis (PROSPERO: CRD42021258328) was performed.

SETTING AND PARTICIPANTS

One hundred studies defining vasoplegia in cardiac surgery patients were systematically reviewed. Sixty studies with 20 or more patients, irrespective of design, reporting vasoplegia incidence, ICU LOS, or 30-day mortality were included for meta-analysis.

INTERVENTIONS

Cardiac surgery on cardiopulmonary bypass.

MEASUREMENTS AND MAIN RESULTS

Studies were categorized depending on the used mean arterial pressure (MAP) thresholds. Random intercept logistic regression models were used for meta-analysis of incidence and mortality. Random effect meta-analysis was used for ICU LOS. One hundred studies were reviewed systematically. MAP and cardiac index thresholds varied considerably (<50-80 mmHg and 2.0-3.5 L·min-1m-2, respectively). Vasopressor dosages also differed between definitions. The reported incidence (60 studies; mean incidence, 19.9%; 95% confidence interval [CI], 16.1-24.4) varied largely between studies (2.5%-66.3%; I2 = 97%; p < 0.0001). Meta-regression models, including the MAP-threshold, did not explain this heterogeneity. Similarly, the effect of vasoplegia on ICU LOS, and 30-day mortality was very heterogeneous among studies (I2 = 99% and I2 = 73%, respectively).

CONCLUSIONS

The large variability in vasoplegia definitions is associated with significant heterogeneity regarding incidence and clinical outcomes, which cannot be explained by factors included in our models. Such variations in definitions leads to inconsistent patient diagnosis and renders published vasoplegia research incomparable.

Effectiveness of Copeptin, MR-proADM and MR-proANP in Predicting Adverse Outcomes, Alone and in Combination with Traditional Severity Scores, a Secondary Analysis in COVID-19 Patients Requiring Intensive Care Admission

Objective: To investigate whether copeptin, MR-proADM and MR-proANP, alone or integrated with the SOFA, MuLBSTA and SAPS II scores, are capable of early recognition of COVID-19 ICU patients at increased risk of adverse outcomes. Methods: For this predefined secondary analysis of a larger cohort previously described, all consecutive COVID-19 adult patients admitted between March and December 2020 to the ICU of a referral, university hospital in Northern Italy were screened, and clinical severity scores were calculated upon admission. A blood sample for copeptin, MR-proADM and MR-proANP was collected within 48 h (T1), on day 3 (T3) and 7 (T7). Outcomes considered were ICU and in-hospital mortality, bacterial superinfection, recourse to renal replacement therapy (RRT) or veno-venous extracorporeal membrane oxygenation, need for invasive mechanical ventilation (IMV) and pronation. Results: Sixty-eight patients were enrolled, and in-hospital mortality was 69.1%. ICU mortality was predicted by MR-proANP measured at T1 (HR 1.005, 95% CI 1.001-1.010, p = 0.049), although significance was lost if the analysis was adjusted for procalcitonin and steroid treatment (p = 0.056). Non-survivors showed higher MR-proADM levels than survivors at all time points, and an increase in the ratio between values at baseline and at T7 > 4.9% resulted in a more than four-fold greater risk of in-hospital mortality (HR 4.417, p < 0.001). Finally, when considering patients with any reduction in glomerular filtration, an early copeptin level > 23.4 pmol/L correlated with a more than five-fold higher risk of requiring RRT during hospitalization (HR 5.305, p = 0.044). Conclusion: Timely evaluation of MR-proADM, MR-proANP and copeptin, as well as changes in the former over time, might predict mortality and other adverse outcomes in ICU patients suffering from severe COVID-19.

Copeptin adaptive response to SGLT2 inhibitors in patients with type 2 diabetes mellitus: The GliRACo study

Introduction

In type 2 diabetes mellitus (T2DM), the antidiuretic system participates in the adaptation to osmotic diuresis further increasing urinary osmolality by reducing the electrolyte-free water clearance. Sodium glucose co-transporter type 2 inhibitors (SGLT2i) emphasize this mechanism, promoting persistent glycosuria and natriuresis, but also induce a greater reduction of interstitial fluids than traditional diuretics. The preservation of osmotic homeostasis is the main task of the antidiuretic system and, in turn, intracellular dehydration the main drive to vasopressin (AVP) secretion. Copeptin is a stable fragment of the AVP precursor co-secreted with AVP in an equimolar amount.

Aim

To investigate the copeptin adaptive response to SGLT2i, as well as the induced changes in body fluid distribution in T2DM patients.

Methods

The GliRACo study was a prospective, multicenter, observational research. Twenty-six consecutive adult patients with T2DM were recruited and randomly assigned to empagliflozin or dapagliflozin treatment. Copeptin, plasma renin activity, aldosterone and natriuretic peptides were evaluated at baseline (T0) and then 30 (T30) and 90 days (T90) after SGLT2i starting. Bioelectrical impedance vector analysis (BIVA) and ambulatory blood pressure monitoring were performed at T0 and T90.

Results

Among endocrine biomarkers, only copeptin increased at T30, showing subsequent stability (7.5 pmol/L at T0, 9.8 pmol/L at T30, 9.5 pmol/L at T90; p = 0.001). BIVA recorded an overall tendency to dehydration at T90 with a stable proportion between extra- and intracellular fluid volumes. Twelve patients (46.1%) had a BIVA overhydration pattern at baseline and 7 of them (58.3%) resolved this condition at T90. Total body water content, extra and intracellular fluid changes were significantly affected by the underlying overhydration condition (p < 0.001), while copeptin did not.

Conclusion

In patients with T2DM, SGLT2i promote the release of AVP, thus compensating for persistent osmotic diuresis. This mainly occurs because of a proportional dehydration process between intra and extracellular fluid (i.e., intracellular dehydration rather than extracellular dehydration). The extent of fluid reduction, but not the copeptin response, is affected by the patient's baseline volume conditions.

Clinical trial registration

Clinicaltrials.gov, identifier NCT03917758.

Copeptin and Stress

Vasopressin (AVP) and copeptin are released in equimolar amounts from the same precursor. Due to its molecular stability and countless advantages as compared with AVP, copeptin perfectly mirrors AVP presence and has progressively emerged as a reliable marker of vasopressinergic activation in response to osmotic and hemodynamic stimuli in clinical practice. Moreover, evidence highlighting the prognostic potential of copeptin in several acute diseases, where the activation of the AVP system is primarily linked to stress, as well as in psychologically stressful conditions, has progressively emerged. Furthermore, organic stressors induce a rise in copeptin levels which, although non-specific, is unrelated to plasma osmolality but proportional to their magnitude: suggesting disease severity, copeptin proved to be a reliable prognostic biomarker in acute conditions, such as sepsis, early post-surgical period, cardiovascular, cerebrovascular or pulmonary diseases, and even in critical settings. Evidence on this topic will be briefly discussed in this article.

Perspectives on glucocorticoid treatment for COVID-19: a systematic review

Coronavirus disease 2019 (COVID-19) is a viral pneumonia that can lead to acute respiratory distress syndrome (ARDS). Until the commercialization of a vaccine, pharmacological treatment still represents an important strategy to fight against the ongoing pandemic. Glucocorticoids (GC) were widely used in the past coronavirus pandemics and have been used against the coronavirus 2 severe acute respiratory syndrome (SARS-CoV-2). This article aimed to review the studies that described the treatment with GC in COVID-19 patients. Randomized or nonrandomized clinical trials and retrospective or prospective-controlled longitudinal studies were screened for this systematic review. Studies in English, Portuguese, and Spanish published since 2019, with participants of any clinical status, geographic location, age, and sex were included. The most significant interest was related to the length of stay, radiological profile changes, viremia, and mortality. The research was done electronically on the Pubmed database using the following terms: "corticosteroids", "glucocorticoids", "dexamethasone", "methylprednisolone", "COVID-19", "SARS- CoV-2", "ADRS". We identified 6332 publications, and at the end, 14 retrospective observational studies that met all the inclusion criteria were selected. These studies included only patients infected with SARS-CoV-2 confirmed by RT-PCR, involving 2,713 participants. The results showed great heterogeneity in their designs and results, which precludes a reliable conclusion on the use of GCs in the treatment of COVID-19.