Characterizing Predictors and Severity of Vasoplegia Syndrome After Heart Transplantation

Vasoplegic syndrome during heart transplantation: A systematic review and meta-analysis

BACKGROUND

Vasoplegic syndrome (VS) is a common occurrence during heart transplantation (HT). It currently lacks a uniform definition between transplant centers, and its pathophysiology and treatment remain enigmatic. This systematic review summarizes the available published clinical data regarding VS during HT.

METHODS

We searched databases for all published reports on VS during HT. Data collected included the incidence of VS in the HT population, patient and intraoperative characteristics, and postoperative outcomes.

RESULTS

Twenty-two publications were included in this review. The prevalence of VS during HT was 28.72% (95% confidence interval: 27.37%, 30.10%). Factors associated with VS included male sex, higher body mass index, hypothyroidism, pre-HT left ventricular assist device or venoarterial extracorporeal membrane oxygenation (VA-ECMO), pre-HT calcium channel blocker or amiodarone usage, longer cardiopulmonary bypass time, and higher blood product transfusion requirement. Patients who developed VS were more likely to require postoperative VA-ECMO support, renal replacement therapy, reoperation for bleeding, longer mechanical ventilation, and a greater 30-day and 1-year mortality.

CONCLUSIONS

The results of our systematic review are an initial step for providing clinicians with data that can help identify high-risk patients and avenues for potential risk mitigation. Establishing guidelines that officially define VS will aid in the precise diagnosis of these patients during HT and guide treatment. Future studies of treatment strategies for refractory VS are needed in this high-risk patient population.

Predictors and Impact of Prolonged Vasoplegia After Continuous-Flow Left Ventricular Assist Device Implantation

Background

Vasoplegia after cardiac surgery is associated with adverse outcomes. However, the clinical effects of vasoplegia and the significance of its duration after continuous-flow left ventricular assist device (CF-LVAD) implantation are less known.

Objectives

This study aimed to identify predictors of and outcomes from transient vs prolonged vasoplegia after CF-LVAD implantation.

Methods

The study was a retrospective review of consecutive patients who underwent CF-LVAD implantation between January 1, 2005, and December 31, 2017. Vasoplegia was defined as the presence of all of the following: mean arterial pressure ≤65 mm Hg, vasopressor (epinephrine, norepinephrine, vasopressin, or dopamine) use for >6 hours within the first 24 hours postoperatively, cardiac index ≥2.2 L/min/m2 and systemic vascular resistance <800 dyne/s/cm5, and vasodilatory shock not attributable to other causes. Prolonged vasoplegia was defined as that lasting 12 to 24 hours; transient vasoplegia was that lasting 6 to <12 hours. Patient characteristics, outcomes, and risk factors were analyzed.

Results

Of the 600 patients who underwent CF-LVAD implantation during the study period, 182 (30.3%) developed vasoplegia. Mean patient age was similar between the vasoplegia and no-vasoplegia groups. Prolonged vasoplegia (n = 78; 13.0%), compared with transient vasoplegia (n = 104; 17.3%), was associated with greater 30-day mortality (16.7% vs 5.8%; P = 0.02). Risk factors for prolonged vasoplegia included preoperative dialysis and elevated body mass index.

Conclusions

Compared with vasoplegia overall, prolonged vasoplegia was associated with worse survival after CF-LVAD implantation. Treatment to avoid or minimize progression to prolonged vasoplegia may be warranted.

Use of intraoperative haemoadsorption in patients undergoing heart transplantation: a proof-of-concept randomized trial

AIMS

The aim of this trial was to compare the clinical effects of intraoperative haemoadsorption versus standard care in patients undergoing orthotopic heart transplantation (OHT).

METHODS AND RESULTS

In a randomized, controlled trial, OHT recipients were randomized to receive intraoperative haemoadsorption or standard care. Outcomes were vasoactive-inotropic score (VIS), frequency of vasoplegic syndrome (VS) in the first 24 h; post-operative change in procalcitonin (PCT) and C-reactive protein (CRP) levels; intraoperative change in mycophenolic acid (MPA) concentration; frequency of post-operative organ dysfunction, major complications, adverse immunological events and length of in-hospital stay and 1-year survival. Sixty patients were randomized (haemoadsorption group N = 30, control group N = 25 plus 5 exclusions). Patients in the haemoadsorption group had a lower median VIS and rate of VS (VIS: 27.2 [14.6-47.7] vs. 41.9 [22.4-63.2], P = 0.046, and VS: 20.0% vs. 48.0%, P = 0.028, respectively), a 6.4-fold decrease in the odds of early VS (OR: 0.156, CI: 0.029-0.830, P = 0.029), lower PCT levels, shorter median mechanical ventilation (MV: 25 [19-68.8] hours vs. 65 [23-287] hours, P = 0.025, respectively) and intensive care unit stay (ICU stay: 8.5 [8.0-10.3] days vs. 12 [8.5-18.0] days, P = 0.022, respectively) than patients in the control group. Patients in the haemoadsorption versus control group experienced lower rates of acute kidney injury (AKI: 36.7% vs. 76.0%, P = 0.004, respectively), renal replacement therapy (RRT: 0% vs. 16.0%, P = 0.037, respectively) and lower median per cent change in bilirubin level (PCB: 2.5 [-24.6 to 71.1] % vs. 72.1 [11.2-191.4] %, P = 0.009, respectively) during the post-operative period. MPA concentrations measured at pre-defined time points were comparable in the haemoadsorption compared to control groups (MPA pre-cardiopulmonary bypass: 2.4 [1.15-3.60] μg/mL vs. 1.6 [1.20-3.20] μg/mL, P = 0.780, and MPA 120 min after cardiopulmonary bypass start: 1.1 [0.58-2.32] μg/mL vs. 0.9 [0.45-2.10] μg/mL, P = 0.786). The rates of cardiac allograft rejection, 30-day mortality and 1-year survival were similar between the groups.

CONCLUSIONS

Intraoperative haemoadsorption was associated with better haemodynamic stability, mitigated PCT response, lower rates of post-operative AKI and RRT, more stable hepatic bilirubin excretion, and shorter durations of MV and ICU stay. Intraoperative haemoadsorption did not show any relevant adsorption effect on MPA. There was no increase in the frequency of early cardiac allograft rejection related to intraoperative haemoadsorption use.

Management of Vasoplegic Shock in the Cardiovascular Intensive Care Unit after Cardiac Surgery

Vasoplegic shock after cardiac surgery is characterized by hypotension, a high cardiac output, and vasodilation. Much of the understanding of this pathologic state is informed by the understanding of septic shock. Adverse outcomes and mortality are increased with vasoplegic shock. Early recognition and a systematic approach to its management are critical. The need for vasopressors to sustain an adequate blood pressure as well as pharmacologic adjuncts to mitigate the inflammatory inciting process are necessary. The rationale behind vasopressor escalation and consideration of adjuncts are discussed.

Incidence of Intraoperative Vasoplegic Syndrome in Lung Transplantation

OBJECTIVES

Severe hypotension and low systemic vascular resistance in the setting of adequate cardiac output, known as "vasoplegic syndrome" (VS), is a physiologic disturbance reported in 9% to 44% of cardiac surgery patients. Although this phenomenon is well-documented in cardiac surgery, there are few studies on its occurrence in lung transplantation. The goal of this study was to characterize the incidence of VS in lung transplantation, as well as identify associated risk factors and outcomes.

DESIGN

Retrospective study of single and bilateral lung transplants from April 2013 to September 2021.

SETTING

The study was conducted at an academic hospital.

PARTICIPANTS

Patients ≥18 years of age who underwent lung transplantation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The authors defined VS as mean arterial pressure <65 mmHg, cardiac index ≥2.2 L/min/m2, and ≥30 minutes of vasopressor administration after organ reperfusion. The association between VS and risk factors or outcomes was assessed using t tests, Mann-Whitney U, and chi-square tests. The authors ran multivariate logistic regression models to determine factors independently associated with VS. The incidence of VS was 13.9% (CI 10.4%-18.4%). In the multivariate model, male sex (odds ratio 2.85, CI 1.07-7.58, p = 0.04) and cystic fibrosis (odds ratio 5.76, CI 1.43-23.09, p = 0.01) were associated with VS.

CONCLUSIONS

The incidence of VS in lung transplantation is comparable to that of cardiac surgery. Interestingly, male sex and cystic fibrosis are strong risk factors. Identifying lung transplant recipients at increased risk of VS may be crucial to anticipating intraoperative complications.

Perioperative Management of Heart Transplantation: A Clinical Review

In this clinical review, the authors summarize the perioperative management of heart transplant patients with a focus on hemodynamics, immunosuppressive strategies, hemostasis and hemorrage, and the prevention and treatment of infectious complications.

Postoperative vasoplegia in lung transplantation: incidence and relation to outcome

BACKGROUND

The incidence and clinical importance of vasoplegia after lung transplantation remains poorly studied. We describe the incidence of vasoplegia and its association with complications after lung transplantation.

METHODS

Perioperative data of 279 lung transplant recipients operated on from 2015 to 2020 were retrospectively analysed.

RESULTS

Vasoplegia occurred in 41.6% of patients after lung transplantation (mild, 31.0%; moderate, 55.2%; severe, 13.8%). Compared with non-vasoplegic patients, vasoplegic patients had a higher incidence of any acute kidney injury, defined by Kidney Disease Improving Global Outcomes (KDIGO) criteria (78.5% vs 65%, P=0.015), renal replacement therapy (47.4% vs 24.5%, P<0.001), and delayed chest closure (18.4% vs 9.2%, P=0.025); were ventilated longer (70 [32-368] vs 34 [19-105] h, P<0.001); and stayed longer in the ICU (12.9 [5-30] vs 6.8 [3-20] days, P<0.001). Mortality at 30 days and 1 yr was higher in patients with vasoplegia (11.2% vs 5.5% and 20.7% vs 11.7%, P=0.039, respectively). Severe vasoplegia represented a predictor of longer-term mortality (hazard ratio=1.65, P=0.008). Underlying infectious disease, increased BMI, higher preoperative pulmonary artery systolic pressure and bilirubin levels, lower glomerular filtration rate, and increased fresh frozen plasma transfusion were predictors of vasoplegia severity. Neutrophilia, leucocytosis, and increased C-reactive protein were associated with vasoplegia, but release of the neutrophil activation markers myeloperoxidase and heparin-binding protein was similar between groups.

CONCLUSIONS

Influenced by preoperative status as well as procedural factors and inflammatory response, vasoplegia is a common and critical condition after lung transplantation with worse short-term outcomes and long-term survival.

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.

Blood Type A1 Mismatch Does Not Affect Heart Transplant Outcomes at One Year

There are subtypes within blood type A, termed non-A1, that have reduced expression of A antigen on cell surfaces. This can result in the development of anti-A1 antibodies. There is limited information regarding the impact of this in heart transplant (HTx) recipients. We conducted a single-center cohort study of 142 Type A HTx recipients in which we compared outcomes of a match group (an A1/O heart into an A1 recipient or a non-A1/O heart into a non-A1 recipient) with a mismatch group (an A1 heart into a non-A1 recipient or a non-A1 heart into an A1 recipient). At one year post-transplant, there were no differences between the groups in survival, freedom from non-fatal major adverse cardiovascular events, freedom from any treated rejection, or freedom from cardiac allograft vasculopathy. There was an increased hospital length of stay in the mismatch group (13.5 vs. 17.1 days, p = 0.04). Our study showed that A1 mismatch was not associated with worse outcomes at one year post-HTx.

The impact of the United Network of Organ Sharing allocation change on waitlist trajectories of inpatients listed with inotropic support: A single-center analysis

BACKGROUND

In the United Network of Organ Sharing (UNOS) allocation scheme prior to October 18, 2018, heart transplant (HTx) candidates with extracorporeal membrane oxygenation (ECMO), temporary mechanical circulatory support (MCS), or pulmonary artery (PA) catheter inotropic support all received Status 1A priority. In revised scheme, patients with PA catheter and inotropic support are Status 3 after those on ECMO (Status 1) or temporary MCS (Status 2). We examined the impact of the allocation change on HTx candidates listed Status 1A versus Status 3 at a high-volume transplant center.

METHODS

Between January 2017 and January 2021, 75 patients were listed with a PA catheter and inotropic support prior to the allocation change (Era 1) and 48 were listed after (Era 2). Clinical characteristics and outcomes were compared for these 123 patients.

RESULTS

Heart transplant (HTx) candidates in Era 2 had higher median inotrope doses at listing. There was no significant difference in inpatient wait list days (12 vs. 20 days, P = .15), transition to temporary MCS (33.3% vs. 22.7%, P = .15), or wait list mortality (6.3% vs. 4.0%, P = .68). There was also no significant difference in survival to transplantation (91.7% vs. 94.7%, P = .71). There were no differences in post-transplant outcomes including 1-year survival (88.6% vs. 93.0%, P = .38).

CONCLUSION

At a high-volume transplant center, the UNOS allocation change did not result in increased wait list time, use of temporary MCS, or mortality on the waitlist or post-transplant for candidates on inotropic support with continuous hemodynamic monitoring.

Clinical approach to vasoplegia in the transplant patient from the Pediatric Heart Transplant Society

This manuscript outlines a clinical approach to vasoplegia incorporating the current state of knowledge regarding vasoplegia in pediatric patients immediately post-transplant and to identify modifiable factors both pre- and post-transplant that may reduce post-operative morbidity, end-organ dysfunction, and mortality. Centers participating in the Pediatric Heart Transplant Society (PHTS) were asked to provide their internal protocols and rationale for vasoplegia management, and applicable adult and pediatric data were reviewed. The authors synthesized the above protocols and literature into the following description of clinical approaches to vasoplegia highlighting areas of both broad consensus and of significant practice variation.

VASOplegia is Predicted by Preoperative Platelet-LEucocyte conGlomerate Indices in Cardiac Surgery (VASOPLEGICS): A retrospective single-center study

Background

Post-cardiotomy vasoplegia syndrome (VS) is often linked to an exaggerated inflammatory response to cardiopulmonary bypass (CPB). At the same time, the prognostic role of platelet-leucocyte indices (PLIs) and leucocyte indices (LIs), (platelet-lymphocyte ratio [PLR], systemic immune-inflammation index [SII = platelet × neutrophil/lymphocyte], aggregate index of systemic inflammation [AISI = platelet × monocyte × neutrophil/lymphocyte], and neutrophil-lymphocyte ratio [NLR], systemic inflammation response index [SIRI = monocyte × neutrophil/lymphocyte), respectively] has been recently described in diverse inflammatory settings.

Methods

The retrospective study was conducted to evaluate the VS predictive performance of PLIs and LIs in 1,045 adult patients undergoing elective cardiac surgery at a tertiary care center. VS was defined by mean blood pressure <60 mmHg, low systemic vascular resistance (SVRI <1,500 dynes.s/cm 5/m2), a normal or high CI (>2.5 L/min/m2), and a normal or reduced central filling pressure despite high-dose vasopressors.

Results

About 205 (19.61%) patients developed VS postoperatively. On univariate analysis, age, diabetes, dialysis-dependent renal failure, preoperative congestive heart failure (CHF), the European System for Cardiac Operative Risk Evaluation (EuroSCORE) II, ejection fraction, NLR, PLR, SII, SIRI, AISI, CPB, and aortic cross clamp (ACC) duration, packed red blood cell (PRBC) transfusion, and time-weighted average blood glucose predicted VS. Subsequent to the multivariate analysis, the predictive performance of EuroSCORE II (OR: 3.236; 95% CI: 2.345-4.468; P < 0.001), CHF (OR: 1.04; 95% CI: 1.02-1.06; P = 0.011), SII (OR: 1.09; 95% CI: 1.02-1.18; P = 0.001), AISI (OR: 1.11; 95% CI: 1.05-1.17; P < 0.001), PRBC (OR: 4.747; 95% CI: 2.443-9.223; P < 0.001), ACC time (OR: 1.003; 95% CI: 1.001-1.005; P = 0.004), and CPB time (OR: 1.016; 95% CI: 1.004-1.028; P = 0.001) remained significant. VS predictive cut-offs of SII and AISI were 1,045 1045×109 /mm3 and 137532×109/mm3, respectively. AISI positively correlated with the postoperative vasoactive-inotropic score (R = 0.718), lactate (R = 0.655), mechanical ventilation duration (R = 0.837), and ICU stay (R = 0.757).

Conclusions

Preoperative elevated SII and AISI emerged as independent predictors of post-cardiotomy VS.

Heart transplantation in muscular dystrophy: Single-center analysis

INTRODUCTION

Cardiac involvement may occur in many forms of muscular dystrophy (MD). While cardiac disease may progress to warrant heart transplantation (HTx), there may be contraindications related to extra-cardiac disease including pulmonary and skeletal muscle involvement that limit overall survival and impairs post-transplant rehabilitation efforts. This study describes the MD HTx experience at a single high-volume center.

METHODS

We examined the clinical characteristics and outcomes of patients with MD with heart failure (HF) (n = 28), patients with MD status post HTx (n = 20) and non-MD HTx control group (n = 40) matched 2:1 for age at transplant, sex, listing status, and antibody sensitization.

RESULTS

Patients with MD who underwent HTx had increased ventilator days (2 vs 1 days, p = 0.013), increased hospital length of stay (20 vs 12 days, p = 0.022), and increased discharge to inpatient rehab (60% vs 8%, p<0.001). By one year post HTx, patients with MD more often required assistive devices for walking (55% vs 10%, p = 0.01). Nonetheless, post-HTx survival was similar at 1 year (100% vs 97.5%, p = 0.48) and 5 years (95.0% vs 87.5%, p = 0.36). Of the HTx recipients with MD, 95% were followed by a neurologist, 60% by a neuromuscular specialist as part of the Muscular Dystrophy Association Clinic at our center.

CONCLUSION

Transplantation is a feasible option for patients with MD and advanced heart failure. MD patients who undergo transplantation may benefit from multidisciplinary specialized care to optimize MD-related morbidity. This article is protected by copyright. All rights reserved.

Vasoplegia Following Orthotopic Heart Transplantation: Prevalence, Predictors and Clinical Outcomes

BACKGROUND

Patients undergoing heart transplant are at high risk for postoperative vasoplegia. Despite its frequency and association with poor clinical outcomes, there remains no consensus definition for vasoplegia, and the predisposing risk factors for vasoplegia remain unclear. Accordingly, the aim of this study was to evaluate the prevalence, predictors, and clinical outcomes associated with vasoplegia in a contemporary cohort of patients undergoing heart transplantation.

METHODS

This was a retrospective cohort study of patients undergoing heart transplantation from January 2015 to December 2019. A binary definition of vasoplegia of a cardiac index of 2.5 L/min/m² or greater and requirement for norepinephrine (≥5 µg/min), epinephrine (≥4 µg/min), or vasopressin (≥1 unit/h) to maintain a mean arterial blood pressure of 65 mm Hg, for 6 consecutive hours during the first 48 hours postoperatively, was used in determining prevalence. Given the relatively low threshold for the binary definition of vasoplegia, patients were divided into tertiles based on their cumulative vasopressor requirement in the 48 hours following transplant. Outcomes included all-cause mortality, intubation time, intensive care unit length of stay, and length of total hospitalization.

RESULTS

After exclusion of patients with primary cardiogenic shock, major bleeding, or overt sepsis, data were collected on 95 eligible patients. By binary definition, vasoplegia incidence was 66.3%. We separately stratified by actual vasopressor requirement tertile (high, intermediate, low). Stratified by tertile, patients with vasoplegia were older (52.7 ± 10.2 vs 46.8 ± 12.7 vs 44.4 ± 11.3 years, P = .02), with higher rates of chronic kidney disease (18.8% vs 32.3% vs 3.1%, P = .01) and were more likely to have been transplanted from left ventricular assist device support (n = 42) (62.5% vs 32.3% vs 37.5%, P = .03). Cardiopulmonary bypass time was prolonged in those that developed vasoplegia (155 min [interquartile range 135-193] vs 131 min [interquartile range 117-152] vs 116 min [interquartile range 102-155], P = .003). Intubation time and length of intensive care unit and hospital stay were significantly increased in those that developed vasoplegia; however, this difference did not translate to a significant increase in all-cause mortality at 30 days or 1 year.

CONCLUSIONS

Vasoplegia occurs at a high rate after heart transplantation. Older age, chronic kidney disease, mechanical circulatory support, and prolonged bypass time are all associated with vasoplegia; however, this study did not demonstrate an associated increase in all-cause mortality LAY SUMMARY: Patients undergoing heart transplantation are at high risk of vasoplegia, a condition defined by low blood pressure despite normal heart function. We found that vasoplegia was common after heart transplant, occurring in 60%-70% of patients after heart transplant after excluding those with other causes for low blood pressure. Factors implicated included age, poor kidney function, prolonged cardiopulmonary bypass time and preoperative left ventricular assist device support. We found no increased risk of death in patients with vasoplegia despite longer lengths of stay in intensive care and in hospital.

Advanced heart failure and heart transplantation in adult congenital heart disease in the current era

BACKGROUND

Adults with congenital heart disease (ACHD) may undergo heart transplantation (HTx) despite increased risk of poor short-term outcomes due to factors including surgical complexity and antibody sensitization. We assessed the clinical characteristics and outcomes of patients with ACHD in the current era referred for HTx at a single high-volume transplant center.

METHODS

From 2010-2020, 37 ACHD patients were evaluated for HTx. ACHD HTx recipients were compared to non-ACHD HTx recipients matched for age, sex, listing status, and prior cardiac surgery.

RESULTS

Of the 37 patients with ACHD, 8 (21.6%) were declined for HTx. Of 29 ACHD patients listed, 19 (65.5%) underwent HTx. Compared with non-ACHD HTx controls, the ACHD HTx recipients had more treated cellular (21.1% vs 15.8%, p = 0.010) and antibody-mediated (15.8% vs 10.5%, p = 0.033) rejection. There was no difference in hospital readmission or allograft vasculopathy at 1 year. There was a nonsignificant higher 1-year mortality in ACHD HTx recipients (21.1% vs 7.9%, p = 0.21).

CONCLUSION

At a high-volume transplant center, ACHD patients undergoing HTx appear to have a marginally higher risk of rejection, but no significant increase in 1-year mortality. With careful selection and management, HTx for patients with ACHD may be feasible in the current era. This article is protected by copyright. All rights reserved.

Vasoplegia from Continuous Flow Left Ventricular Assist Devices

PURPOSE OF REVIEW

The contribution of continuous flow left ventricular assist devices (c-LVAD) to vasoplegic syndrome and postoperative outcomes after orthotopic heart transplant (OHT) is contested in the literature. A standardized definition of vasoplegic syndrome (VS) is needed to better recognize and manage vasoplegic shock.

RECENT FINDINGS

Vasoplegic syndrome occurs after orthotopic heart transplant more frequently than after other surgeries requiring cardiopulmonary bypass. c-LVADs lead to small vessel endothelial dysfunction and desensitized adrenal receptors; however, their contribution to the development of vasoplegia is debated in clinical studies. Pulsatility may mitigate vascular dysfunction resulting from long-term continuous flow, and should be further explored in the clinical setting when considering risk factors for vasoplegic syndrome. The incidence of vasoplegic syndrome after orthotopic heart transplant is rising with the increasing use of c-LVAD bridge to therapy. Robust clinical studies are needed to advance our understanding and approach to mitigating VS after OHT.

Vasoplegia in patients following ventricular assist device explant and heart transplantation

BACKGROUND

Vasoplegia has been shown to be associated with increased morbidity and mortality in patients undergoing cardiac surgery. It has been previously stated that low pulsatile states as seen with current left ventricular assist devices (LVADs) may contribute to vasoplegia post LVAD-explant and heart transplant. We sought to examine the literature regarding vasoplegia in the post-operative setting for patients undergoing LVAD explant and heart transplant.

METHOD

A literature review was conducted to firstly define vasoplegia in the setting of LVAD patients, and secondly to better understand the relationship between vasoplegia and LVAD explantation in the postoperative heart transplant patient cohort. A keyword search of 'vasoplegia' OR 'vasoplegic' AND 'transplant' was used. Search engines used were PubMed, Cochrane Library, ClinicalTrials.gov, Ovid, Scopus and grey literature.

RESULTS

17 studies met the selection criteria for review. Three key themes emerged from the literature. Firstly, there is limited consensus regarding the definition of vasoplegia. Secondly, patients with LVADs experienced higher rates of vasoplegia following heart transplant than their counterparts and thirdly, increased cardiopulmonary bypass time was associated with a higher rate of vasoplegia.

CONCLUSION

Vasoplegia is not clearly defined in the literature as it pertains to the LVAD patient cohort. Patients bridged with LVADs appear to have higher rates of vasoplegia, however the aetiology of this is unclear and may be associated with continuous flow physiology or prolonged cardiopulmonary bypass time. A universal definition will aid in risk stratification, early recognition and management.

Altered kinetics of circulating progenitor cells in cardiopulmonary bypass (CPB) associated vasoplegic patients: A pilot study

Vasoplegia observed post cardiopulmonary bypass (CPB) is associated with substantial morbidity, multiple organ failure and mortality. Circulating counts of hematopoietic stem cells (HSCs) and endothelial progenitor cells (EPC) are potential markers of neo-vascularization and vascular repair. However, the significance of changes in the circulating levels of these progenitors in perioperative CPB, and their association with post-CPB vasoplegia, are currently unexplored. We enumerated HSC and EPC counts, via flow cytometry, at different time-points during CPB in 19 individuals who underwent elective cardiac surgery. These 19 individuals were categorized into two groups based on severity of post-operative vasoplegia, a clinically insignificant vasoplegic Group 1 (G1) and a clinically significant vasoplegic Group 2 (G2). Differential changes in progenitor cell counts during different stages of surgery were compared across these two groups. Machine-learning classifiers (logistic regression and gradient boosting) were employed to determine if differential changes in progenitor counts could aid the classification of individuals into these groups. Enumerating progenitor cells revealed an early and significant increase in the circulating counts of CD34+ and CD34+CD133+ hematopoietic stem cells (HSC) in G1 individuals, while these counts were attenuated in G2 individuals. Additionally, EPCs (CD34+VEGFR2+) were lower in G2 individuals compared to G1. Gradient boosting outperformed logistic regression in assessing the vasoplegia grouping based on the fold change in circulating CD 34+ levels. Our findings indicate that a lack of early response of CD34+ cells and CD34+CD133+ HSCs might serve as an early marker for development of clinically significant vasoplegia after CPB.

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.

Incidence of vasoplegic syndrome after cardiac transplantation in patients treated with sacubitril/valsartan

Vasoplegic syndrome (VS) is associated with poor outcomes after heart transplantation (HT). Our aim was to determine whether SAC/VALS is associated with VS after HT. We retrospectively analyzed all consecutive HT performed in three centers between January 2017 and August 2018. VS was defined as vasopressor need (norepinephrine or epinephrine >.5 mcg/kg/min or vasopressin) for more than 24 hours to maintain a mean arterial pressure >70 mm Hg. Ninety-six recipients underwent HT in the study period: 60 elective HT with no LVAD, 5 elective HT on long term LVAD, and 31 emergent HT: 3 on long-term LVAD and 28 on temporary mechanical circulatory support. Fourteen patients were on SAC/VALS treatment at the time of transplant, and 82 were not. The global incidence of VS was 15.6%, with no significant differences between the groups (7.14% in with SAC/VALS vs 17.07% in no-SAC/VALS). In conclusion, in our small cohort SAC/VALS was not associated with VS development.

Vasoplegia During Cardiopulmonary Bypass: Current Literature and Rescue Therapy Options

Vasoplegia syndrome in the cardiac surgical intensive care unit and postoperative period has been an area of interest to clinicians because of its prevalence and effects on morbidity and mortality. However, there is a paucity of evidence regarding the treatment of vasoplegia syndrome during cardiopulmonary bypass (on-CPB VS). This review aims to detail the incidence, outcomes, and possible treatment options for patients who develop vasoplegia during bypass. The pharmacologic rescue agents discussed are used in cases in which vasoplegia during CPB is refractory to standard catecholamine agents, such as norepinephrine, epinephrine, and phenylephrine. Methods to improve vasoplegia during CPB can be both pharmacologic and nonpharmacologic. In particular, optimization of CPB parameters plays an important nonpharmacologic role in vasoplegia during CPB. Pharmacologic agents that have been demonstrated as being effective in vasoplegia include vasopressin, terlipressin, methylene blue, hydroxocobalamin, angiotensin II (Giapreza), vitamin C, flurbiprofen (Ropion), and hydrocortisone. Although these agents have not been specifically evaluated for vasoplegia during CPB, they have shown signs of effectiveness for vasoplegia postoperatively to varying degrees. Understanding the evidence for, dosing, and side effects of these agents is crucial for cardiac anesthesiologists when treating vasoplegia during CPB bypass.

Predictors and Clinical Outcomes of Vasoplegia in Patients Bridged to Heart Transplantation With Continuous-Flow Left Ventricular Assist Devices

Background

The presence of a durable left ventricular assist device (LVAD) is associated with increased risk of vasoplegia in the early postoperative period following heart transplantation (HT). However, preoperative predictors of vasoplegia and its impact on survival after HT are unknown. We sought to examine predictors and outcomes of patients who develop vasoplegia after HT following bridging therapy with an LVAD.

Methods and Results

We identified 94 patients who underwent HT after bridging with continuous‐flow LVAD from 2008 to 2018 at a single institution. Vasoplegia was defined as persistent low vascular resistance requiring ≥2 intravenous vasopressors within 48 hours after HT for >24 hours to maintain mean arterial pressure >70 mm Hg. Overall, 44 patients (46.8%) developed vasoplegia after HT. Patients with and without vasoplegia had similar preoperative LVAD, echocardiographic, and hemodynamic parameters. Patients with vasoplegia were significantly older; had longer LVAD support, higher preoperative creatinine, longer cardiopulmonary bypass time, and higher Charlson comorbidity index; and more often underwent combined organ transplantation. In a multivariate logistic regression model, older age (odds ratio: 1.08 per year; P=0.010), longer LVAD support (odds ratio: 1.06 per month; P=0.007), higher creatinine (odds ratio: 3.9 per 1 mg/dL; P=0.039), and longer cardiopulmonary bypass time (odds ratio: 1.83 per hour; P=0.044) were independent predictors of vasoplegia. After mean follow‐up of 4.0 years after HT, vasoplegia was associated with increased risk of all‐cause mortality (hazard ratio: 5.20; 95% CI, 1.71–19.28; P=0.003).

Conclusions

Older age, longer LVAD support, impaired renal function, and prolonged intraoperative CPB time are independent predictors of vasoplegia in patients undergoing HT after LVAD bridging. Vasoplegia is associated with worse prognosis; therefore, detailed assessment of these predictors can be clinically important.

Impact of Bridge to Transplantation With Continuous-Flow Left Ventricular Assist Devices on Posttransplantation Mortality

BACKGROUND

Bridge to transplantation (BTT) with left ventricular assist devices (LVADs) is a mainstay of therapy for heart failure in patients awaiting heart transplantation (HT). Criteria for HT listing do not differ between patients medically managed and those mechanically bridged to HT. The objectives of the present study were to evaluate the impact of BTT with LVAD on posttransplantation survival, to describe differences in causes of 1-year mortality in medically and mechanically bridged patients, and to evaluate differences in risk factors for 1-year mortality between those with and those without LVAD at the time of HT.

METHODS

Using the United Network of Organ Sharing database, we identified 5486 adult, single-organ HT recipients transplanted between 2008 and 2015. Patients were propensity matched for likelihood of LVAD at the time of HT. Kaplan-Meier survival estimates were used to assess the impact of BTT on 1- and 5-year mortality. Logistic regression analysis was used to evaluate the odds ratio of 1-year mortality for patients BTT with LVAD compared with those with medical management across clinically significant variables at various thresholds.

RESULTS

Early mortality was higher in mechanically bridged patients: 9.5% versus 7.2% mortality at 1 year (P<0.001). BTT patients incurred an increased risk of 1-year mortality with an estimated glomerular filtration rate of 40 to 60 mL·min^-1·1.73 m^-2 (odds ratio, 1.69; P=0.003) and <40 mL·min^-1·1.73 m^-2 (odds ratio, 2.16; P=0.005). A similar trend was seen in patients with a body mass index of 25 to 30 kg/m² (odds ratio, 1.88; P=0.024) and >30 kg/m² (odds ratio, 2.11; P<0.001). When patients were stratified by BTT status and the presence of risk factors, including age >60 years, estimated glomerular filtration rate <40 mL·min^-1·1.73 m^-2, and body mass index >30 kg/m², there were significant differences in 1-year mortality between medium- and high-risk medically and mechanically bridged patients, with 1-year mortality in high-risk BTT patients at 17.6% compared with 10.4% in high-risk medically managed patients.

CONCLUSIONS

Bridge to HT with LVAD, although necessary because of organ scarcity and capable of improving wait list survival, confers a significantly higher risk of early posttransplantation mortality. Patients bridged with mechanical support may require more careful consideration for transplant eligibility after LVAD placement.

Management of primary graft failure after heart transplantation: Preoperative risks, perioperative events, and postoperative decisions

Primary graft failure (PGF) after heart transplantation (HT) is a devastating and unexpected event characterized by failure of the graft to adequately support recipient circulation necessitating high doses of vasopressors and inotropes and/or temporary mechanical circulatory support. Although it represents an increasingly common event in the current era, there remains a high degree of variability in prevalence, reported risk factors, and approach to this clinical entity. The purpose of the current review is to highlight preoperative considerations including known incidence and risk factors, perioperative issues involving the identification and management of PGF, and postoperative decisions related to weaning of mechanical circulatory support and titration of immunosuppressive therapy. Lastly, we highlight future directions in PGF research, involving basic and translational research, that have the potential to uncover novel strategies of risk stratification and treatment. CASE: Our patient is a 53-year-old man with end-stage non-ischemic dilated cardiomyopathy complicated by ventricular tachycardia (VT), post-capillary pulmonary hypertension, and renal insufficiency. After progressing to NYHA Class IV symptoms, he underwent implantation of a durable left ventricular assist device (LVAD) as bridge to transplant (BTT). On device support, he developed recurrent VT resulting in multiple defibrillator discharges and hospital admission for intravenous anti-arrhythmic therapy. He is subsequently upgraded to a higher status on the waiting list. A suitable donor is identified, with an appropriate predicted heart mass and an anticipated ischemic time of <4 hours. He is taken to the operating room, where at the time of anesthesia induction he develops vasodilatory shock, requiring high-dose vasopressors, and cardiopulmonary bypass (CPB) support for dissection. After surgical anastomosis, cross clamp removal and reperfusion, graft function is extremely poor, there is significant bradycardia requiring pacing, and the patient is unable to be weaned successfully from CPB. Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is initiated, and the patient is transferred to the intensive care unit. Retrospective flow crossmatch is negative. This patient is suffering from severe primary graft failure.

Postoperative kidney oxygen saturation as a novel marker for acute kidney injury after adult cardiac surgery

OBJECTIVE

Acute kidney injury is a severe complication and one of the stronger risk factors for death in patients undergoing cardiac surgery. The relationship between postoperative brain oxygen saturation and kidney oxygen saturation with acute kidney injury in adults undergoing cardiac surgery has not been determined. We designed a single-center prospective study to determine if the continuous monitoring of postoperative brain oxygen saturation and kidney oxygen saturation could predict postoperative acute kidney injury.

METHODS

We conducted a prospective open cohort study from January to September 2017. The primary outcome was postoperative acute kidney injury using the Kidney Disease: Improving Global Outcomes criteria. Brain oxygen saturation and kidney oxygen saturation, the metrics of which were area measurements (%-min), were recorded during the surgery and the first 48 hours after the cardiac procedure. Receiver operating characteristic curve analysis was used to evaluate the predictive power of kidney oxygen saturation for acute kidney injury.

RESULTS

A total of 121 consecutive patients were enrolled. Thirty-five patients (28.9%) developed acute kidney injury. Brain oxygen saturation showed no statistical difference in both groups; however, kidney oxygen saturation was related to acute kidney injury (P = .001). Receiver operating characteristic curve analysis showed that kidney oxygen saturation could predict the risk of acute kidney injury. Kidney oxygen saturation less than 65% (area under the curve-receiver operating characteristic, 0.679 ± 0.054, 95% confidence interval, 0.573-0.785, P = .002) and 20% decrease from baseline (area under the curve-receiver operating characteristic, 0.639 ± 0.059, 95% confidence interval, 0.523-0.755, P = .019) showed the better performance, respectively.

CONCLUSIONS

Postoperative kidney oxygen saturation is related to the development of cardiac surgery-associated acute kidney injury. Continuous kidney saturation monitoring might be a promising, noninvasive tool for predicting acute kidney injury during the postoperative period for adult patients after cardiac surgery.

Determinants and Outcomes of Vasoplegia Following Left Ventricular Assist Device Implantation

BACKGROUND

Vasoplegia is associated with adverse outcomes following cardiac surgery; however, its impact following left ventricular assist device implantation is largely unexplored.

METHODS AND RESULTS

In 252 consecutive patients receiving a left ventricular assist device, vasoplegia was defined as the occurrence of normal cardiac function and index but with the need for intravenous vasopressors within 48 hours following surgery for >24 hours to maintain a mean arterial pressure >70 mm Hg. We further categorized vasoplegia as none; mild, requiring 1 vasopressor (vasopressin, norepinephrine, or high-dose epinephrine [>5 μg/min]); or moderate to severe, requiring ≥2 vasopressors. Predictors of vasoplegia severity were determined using a cumulative logit (ordinal logistic regression) model, and 1-year mortality was evaluated using competing-risks survival analysis. In total, 67 (26.6%) patients developed mild vasoplegia and 57 (22.6%) developed moderate to severe vasoplegia. The multivariable model for vasoplegia severity utilized preoperative Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile, central venous pressure, systolic blood pressure, and intraoperative cardiopulmonary bypass time, which yielded an area under the curve of 0.76. Although no significant differences were noted in stroke or pump thrombosis rates (P=0.87 and P=0.66, respectively), respiratory failure and major bleeding increased with vasoplegia severity (P<0.01). Those with moderate to severe vasoplegia had a significantly higher risk of mortality than those without vasoplegia (adjusted hazard ratio: 2.12; 95% confidence interval, 1.08-4.18; P=0.03).

CONCLUSIONS

Vasoplegia is predictive of unfavorable outcomes, including mortality. Risk factors for future research include preoperative INTERMACS profile, central venous pressure, systolic blood pressure, and intraoperative cardiopulmonary bypass time.