Low systemic vascular resistance after cardiopulmonary bypass: incidence, etiology, and clinical importance

Nicardipine or Nitroprusside for Postoperative Blood Pressure Control in Infants After Surgery for Congenital Heart Disease: Single-Center Retrospective Noninferiority and Cost Analysis, 2016-2020

OBJECTIVES

Postoperative hypertension frequently occurs after surgery for congenital heart disease. Given safety concerns when using calcium channel blockers in infants along with the cost and side-effect profile of nitroprusside, we retrospectively assessed our experience of using nicardipine and nitroprusside for postoperative blood pressure control in infants who underwent surgery for congenital heart disease. We also investigated the cost difference between the medications.

DESIGN

This study was a single-center retrospective, pre-post chart review of patients who had surgery for congenital heart disease between 2016 and 2020. The primary aim was a noninferiority comparison of achievement of blood pressure goal at 1-hour post-initiation of an antihypertensive agent. Secondary comparisons included achievement of blood pressure goal at 2 hours after medication initiation, Vasoactive-Inotropic Score (VIS), and blood transfusion, crystalloid volume, and calcium needs.

SETTING

Academic quaternary-care center.

PATIENTS

Infants under 1 year old who required treatment for hypertension with nitroprusside (n = 71) or nicardipine (n = 52) within 24 hours of surgery for congenital heart disease.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We failed to identify any difference in proportion of patients that achieved blood pressure control at 1-hour after medication initiation (nitroprusside 52% vs. nicardipine 54%; p = 0.86), with nicardipine noninferior to nitroprusside within a 15% margin. Of patients who did not achieve control at 1-hour post-medication initiation, receiving nicardipine was associated with blood pressure control at 2 hours post-medication initiation (79% vs. 38%; p = 0.003). We also failed to identify an association between antihypertensive types and mean VIS scores, blood transfusion volumes, crystalloid volumes, and quantities of calcium administered. Index cost of using nitroprusside was 16 times higher than using nicardipine, primarily due to difference in wholesale cost.

CONCLUSIONS

In our experience of achieving blood pressure control in infants after surgery for congenital heart disease (2016-2020), antihypertensive treatment with nicardipine was noninferior to nitroprusside. Furthermore, nicardipine use was significantly less expensive than nitroprusside. Our contemporary practice is therefore to use nicardipine in preference to nitroprusside.

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.

Myocardial protection in cardiac surgery-hindsight from the 2020s

Myocardial protection and specifically cardioplegia have been extensively investigated in the beginnings of cardiac surgery. After cardiopulmonary bypass had become routine, more and more cardiac operations were possible, requiring reliable and reproducible protection for times of blood flow interruptions to the most energy-demanding organ of the body. The concepts of hypothermia and cardioplegia evolved as tools to extend cardiac ischaemia tolerance to a degree considered safe for the required operation. A plethora of different solutions and delivery techniques were developed achieving remarkable outcomes with cross-clamp times of up to 120 min and more. With the beginning of the new millennium, interest in myocardial protection research declined and, as a consequence, conventional cardiac surgery is currently performed using myocardial protection strategies that have not changed in decades. However, the context, in which cardiac surgery is currently performed, has changed during this time. Patients are now older and suffer from more comorbidities and, thus, other organs move more and more into the centre of risk assessment. Yet, systemic effects of cardioplegic solutions have never been in the focus of attention. They say hindsight is always 20-20. We therefore review the biochemical principles of ischaemia, reperfusion and cardioplegic extension of ischaemia tolerance and address the concepts of myocardial protection with 'hindsight from the 2020s'. In light of rising patient risk profiles, minimizing surgical trauma and improving perioperative morbidity management becomes key today. For cardioplegia, this means accounting not only for cardiac, but also for systemic effects of cardioplegic solutions.

Role of Pv-aCO2 gradient and Pv-aCO2/Ca-vO2 ratio during cardiac surgery: a retrospective observational study

INTRODUCTION

Arterial lactate, mixed venous O2 saturation, venous minus arterial CO2 partial pressure (Pv-aCO2) and the ratio between this gradient and the arterial minus venous oxygen content (Pv-aCO2/Ca-vO2) were proposed as markers of tissue hypoperfusion and oxygenation. The main goals were to characterize the determinants of Pv-aCO2 and Pv-aCO2/Ca-vO2, and the interchangeability of the variables calculated from mixed and central venous samples.

METHODS

35 cardiac surgery patients were included. Variables were measured or calculated: after anesthesia induction (T1), end of surgery (T2), and at 6...8.ßhours intervals after ICU admission (T3 and T4).

RESULTS

Macrohemodynamics was characterized by increased cardiac index and low systemic vascular resistances after surgery (p.ß<.ß0.05). Hemoglobin, arterial-pH, lactate, and systemic O2 metabolism showed significant changes during the study (p.ß<.ß0.05). Pv-aCO2 remained high and without changes, Pv-aCO2/Ca-vO2 was also high and decreased at T4 (p.ß<.ß0.05). A significant correlation was observed globally and at each time interval, between Pv-aCO2 or Pv-aCO2/Ca-vO2 with factors that may affect the CO2 hemoglobin dissociation. A multilevel linear regression model with Pv-aCO2 and Pv-aCO2/Ca-vO2 as outcome variables showed a significant association for Pv-aCO2 with SvO2, and BE (p.ß<.ß0.05), while Pv-aCO2/Ca-vO2 was significantly associated with Hb, SvO2, and BE (p.ß<.ß0.05) but not with cardiac output. Measurements and calculations from mixed and central venous blood were not interchangeable.

CONCLUSIONS

Pv-aCO2 and Pv-aCO2/Ca-vO2 could be influenced by different factors that affect the CO2 dissociation curve, these variables should be considered with caution in cardiac surgery patients. Finally, central venous and mixed values were not interchangeable.

Review of Postoperative Care for Heart Transplant Recipients

The early postoperative management strategies after heart transplantation include optimizing the function of the denervated heart, correcting the causes of hemodynamic instability, and initiating and maintaining immunosuppressive therapy, allograft rejection surveillance, and prophylaxis against infections caused by immunosuppression. The course of postoperative support is influenced by the quality of allograft myocardial protection prior to implantation and reperfusion, donor-recipient heart size matching, surgical technique of orthotopic heart transplantation, and patient factors (eg, preoperative condition, immunologic compatibility, postoperative vasomotor tone, severity and reversibility of pulmonary vascular hypertension, pulmonary function, mediastinal blood loss, and end-organ perfusion). This review provides an overview of the early postoperative care of recipients and includes a brief description of the surgical techniques for orthotopic heart transplantation.

Prolonged cardiovascular pharmacological support and fluid management after cardiac surgery

OBJECTIVE

To identify potentially modifiable risk factors related to prolonged cardiovascular pharmacological support after weaning from cardiopulmonary bypass (CPB).

METHODS

This is a secondary analysis of two prospective cohort study in a specialized cardiac surgery institution in adult patients undergoing cardiac surgery with the use of CPB between August 2016 and July 2017. Prolonged cardiovascular pharmacological support was defined by the need for at least one vasopressor or one inotropic agent 24 hours after separation from CPB. Risk factors were identified among baseline characteristics and peri-operative events through multivariable logistic regression.

RESULTS

A total of 247 patients were included and 98 (39.7%) developed prolonged pharmacological support. In multivariable analysis, left ventricular ejection fraction ≤ 30% (OR 9.52, 95% confidence interval (CI) 1.14; 79.25), elevated systolic pulmonary artery pressure (sPAP) > 30 and ≤ 55 mmHg (moderate) (OR 2.52, CI 1.15; 5.52) and sPAP > 55 mmHg (severe) (OR 8.12, CI 2.54; 26.03), as well as cumulative fluid balance in the first 24 hours after surgery (OR 1.76, CI 1.32; 2.33) were independently associated with the development of prolonged pharmacological support.

CONCLUSIONS

Prolonged cardiovascular pharmacological support is frequent after cardiac surgery on CPB. Severe LV systolic dysfunction, preoperative pulmonary hypertension and postoperative fluid overload are risk factors. Further studies are required to explore if those risk factors could be modified or not.

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.

Prevention of vasoplegia with CytoSorb in heart failure patients undergoing cardiac surgery (CytoSorb-HF trial): protocol for a randomised controlled trial

INTRODUCTION

Vasoplegia is a common complication after cardiac surgery and is associated with poor prognosis. It is characterised by refractory hypotension despite normal or even increased cardiac output. The pathophysiology is complex and includes the systemic inflammatory response caused by cardiopulmonary bypass (CPB) and surgical trauma. Patients with end-stage heart failure (HF) are at increased risk for developing vasoplegia. The CytoSorb adsorber is a relatively new haemoadsorption device which can remove circulating inflammatory mediators in a concentration based manner. The CytoSorb-HF trial aims to evaluate the efficacy of CytoSorb haemoadsorption in limiting the systemic inflammatory response and preventing postoperative vasoplegia in HF patients undergoing cardiac surgery with CPB.

METHODS AND ANALYSIS

This is an investigator-initiated, single-centre, randomised, controlled clinical trial. In total 36 HF patients undergoing elective cardiac surgery with an expected CPB duration of more than 120 min will be randomised to receive CytoSorb haemoadsorption along with standard surgical treatment or standard surgical treatment alone. The primary endpoint is the change in systemic vascular resistance index with phenylephrine challenge after CPB. Secondary endpoints include inflammatory markers, sublingual microcirculation parameters and 30-day clinical indices. In addition, we will assess the cost-effectiveness of using the CytoSorb adsorber. Vascular reactivity in response to phenylephrine challenge will be assessed after induction, after CPB and on postoperative day 1. At the same time points, and before induction and on postoperative day 4 (5 time points in total), blood samples will be collected and the sublingual microcirculation will be recorded. Study participants will be followed up until day 30.

ETHICS AND DISSEMINATION

The trial protocol was approved by the Medical Ethical Committee of Leiden The Hague Delft (METC LDD, registration number P20.039). The results of the trial will be published in peer-reviewed medical journals and through scientific conferences.

TRIAL REGISTRATION NUMBER

NCT04812717.

Effect of preoperative renin-angiotensin system blockade on vasoplegia after cardiac surgery: A systematic review with meta-analysis

BACKGROUND

Vasoplegia is a common complication of cardiac surgery but its causal relationship with preoperative use of renin angiotensin system (RAS) blockers [angiotensin converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARB)] is still debated.

AIM

To update and summarize data on the effect of preoperative use of RAS blockers on incident vasoplegia.

METHODS

All published studies from MEDLINE, EMBASE, and Web of Science providing relevant data through January 13, 2021 were identified. A random-effects meta-analysis method was used to pool estimates, and post-cardiac surgery shock was differentiated from vasoplegia.

RESULTS

Ten studies reporting on a pooled population of 15672 patients (none looking at ARBs exclusively) were included in the meta-analysis. All were case-control studies. Use of ACEIs was associated with an increased risk of vasoplegia [pooled adjusted odds ratio (Aor) of 2.06, 95%CI: 1.45-2.93] and increased inotropic/vasopressor support requirement (pooled aOR 1.19, 95%CI: 1.10-1.29). Post-cardiac surgery shock was increased in the presence of left ventricular dysfunction (pooled aOR 2.32, 95%CI: 1.60-3.36; I² 49%) but not increased by the use of beta blockers (pooled aOR 0.78, 95%CI: 0.36-1.69; I² 77%). Two randomized control trials (RCTs), not eligible for the meta-analysis, did not show an association between continuation of RAS blockers and vasoplegia.

CONCLUSION

Preoperative continuation of ACEIs is associated with an increased need for inotropic support postoperatively and with an increased risk of vasoplegia in observational studies but not in RCTs. The absence of a consensus definition of vasoplegia should lead to the use of perioperative cardiovascular monitoring when designing RCTs to better understand this discrepancy.

The effect of calcium gluconate administration during cardiopulmonary bypass on hemodynamic variables in infants undergoing open-heart surgery

Background

The incidence of complications after heart surgery is a critical factor in disability, deaths, lengthening hospital stays, and increasing treatment costs. The metabolic balance of certain hormones and electrolytes is necessary for proper cardiac function. In children, various biochemical conditions may cause calcium depletion during heart surgery. The purpose of this study was to determine the effect of calcium gluconate administration during cardiopulmonary bypass on hemodynamic variables and clinical outcomes in infants undergoing open-heart surgery. This study was conducted at Rajaie Cardiovascular Medical and Research Center in 2021 using a controlled randomized clinical trial. A total of 60 patients with open-heart surgery weighing up to 10 kg were included in the study. The first group received an intravenous injection of calcium gluconate 20 min after opening the aortic clamp, and the second group was monitored as a control group. Data collection tools included checklists containing demographics, surgical information, and intensive care unit measures.

Results

The Chi-square test or Fisher's exact test showed that the frequency distribution of gender, blood group, Rhesus factor (RH), and clinical diagnosis in the two groups of intervention and control was not statistically significant (p < 0.05). The mean and standard deviation of Ejection Fraction (EF) changes (before and after) were 13.27 ± 9.16 in the intervention group and 8.31 ± 9.80 in the control group (p = 0.065). The results of two-way repeated measures ANOVA showed that mean systolic blood pressure (p = 0.030), mean diastolic blood pressure (p = 0.021), mean heart rate (p = 0.025), mean arterial pressure (p = 0.020), mean pH (p < 0.001), and mean hemoglobin (p = 0.018) in the intervention, and control groups were statistically significant.

Conclusions

In the present study, unlike systolic pressure, mean diastolic blood pressure decreased, and mean arterial pressure increased significantly. As a result, the slope of changes during the study period was different in the intervention and control groups.

Effects of methylene blue on microcirculatory alterations following cardiac surgery: A prospective cohort study

BACKGROUND

Methylene blue is used as rescue therapy to treat catecholamine-refractory vasoplegic syndrome after cardiac surgery. However, its microcirculatory effects remain poorly documented.

OBJECTIVE

We aimed to study microcirculatory abnormalities in refractory vasoplegic syndrome following cardiac surgery with cardiopulmonary bypass and assess the effects of methylene blue.

DESIGN

A prospective open-label cohort study.

SETTING

20-Bed ICU of a tertiary care hospital.

PATIENTS

25 Adult patients receiving 1.5 mg kg-1 of methylene blue intravenously for refractory vasoplegic syndrome (defined as norepinephrine requirement more than 0.5 μg kg-1 min-1) to maintain mean arterial pressure (MAP) more than 65 mmHg and cardiac index (CI) more than 2.0 l min-1 m-2.

MAIN OUTCOME MEASURES

Complete haemodynamic set of measurements at baseline and 1 h after the administration of methylene blue. Sublingual microcirculation was investigated by sidestream dark field imaging to obtain microvascular flow index (MFI), total vessel density, perfused vessel density and heterogeneity index. Microvascular reactivity was assessed by peripheral near-infrared (IR) spectroscopy combined with a vascular occlusion test. We also performed a standardised measurement of capillary refill time.

RESULTS

Despite normalised CI (2.6 [2.0 to 3.8] l min-1 m-2) and MAP (66 [55 to 76] mmHg), patients with refractory vasoplegic syndrome showed severe microcirculatory alterations (MFI < 2.6). After methylene blue infusion, MFI significantly increased from 2.0 [0.1 to 2.5] to 2.2 [0.2 to 2.8] (P = 0.008), as did total vessel density from 13.5 [8.3 to 18.5] to 14.9 [10.1 to 14.7] mm mm-2 (P = 0.02) and perfused vessel density density from 7.4 [0.1 to 11.5] to 9.1 [0 to 20.1] mm mm-2 (P = 0.02), but with wide individual variation. Microvascular reactivity assessed by tissue oxygen resaturation speed also increased from 0.5 [0.1 to 1.8] to 0.7 [0.1 to 2.7]% s-1 (P = 0.002). Capillary refill time remained unchanged throughout the study.

CONCLUSION

In refractory vasoplegic syndrome following cardiac surgery, we found microcirculatory alterations despite normalised CI and MAP. The administration of methylene blue could improve microvascular perfusion and reactivity, and partially restore the loss of haemodynamic coherence.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04250389.

Closed-Loop Bowel Obstruction Years After an Open Abdominal Aortic Aneurysm Repair

A 68-year-old male has a significant past medical history of severe aortic stenosis, peripheral arterial disease, chronic kidney disease, and an abdominal aortic aneurysm treated with a bifurcated interposition aortobiiliac graft. He was admitted to the hospital for an elective one-vessel coronary artery bypass graft and placement of a bioprosthetic aortic valve. Postoperatively, he developed worsening abdominal pain, leukocytosis, and inability to tolerate nutrition by mouth. Computed tomography revealed moderately dilated loops of the small bowel with two transition points in the right lower quadrant. He was taken emergently to the operating room for an exploratory laparotomy, and a 28-cm necrotic jejunal loop was entrapped posterior to the right iliac segment of the graft. In a patient with an intra-abdominal synthetic vascular graft, a closed-loop bowel obstruction caused by entrapment by the vascular graft is exceptionally rare; however, it should be considered in the presence of bowel obstruction.

Prediction of Short-Term Mortality With Renal Replacement Therapy in Patients With Cardiac Surgery-Associated Acute Kidney Injury

Objective: We aimed to: (1) explore the risk factors that affect the prognosis of cardiac surgery-associated acute kidney injury (CS-AKI) in patients undergoing renal replacement therapy (RRT) and (2) investigate the predictive value of the Acute Physiology and Chronic Health Evaluation (APACHE) III score, Sequential Organ Failure Assessment (SOFA) score, and Vasoactive-Inotropic Score (VIS) for mortality risk in patients undergoing RRT. Methods: Data from patients who underwent cardiac surgery from January 2015 through February 2021 were retrospectively reviewed to calculate the APACHE III score, SOFA score, and VIS on the first postoperative day and at the start of RRT. Various risk factors influencing the prognosis of the patients during treatment were evaluated; the area under the receiver operating characteristics curve (AUCROC) was used to measure the predictive ability of the three scores. Independent risk factors influencing mortality were analyzed using multivariable binary logistic regression. Results: A total of 90 patients were included in the study, using 90-day survival as the end point. Of those patients, 36 patients survived, and 54 patients died; the mortality rate reached 60%. At the start of RRT, the AUCROC of the APACHE III score was 0.866 (95% CI: 0.795-0.937), the VIS was 0.796 (95% CI: 0.700-0.892), and the SOFA score was 0.732 (95% CI: 0.623-0.842). The AUCROC-value of the APACHE III score on the first postoperative day was 0.790 (95% CI: 0.694-0.885). After analyzing multiple factors, we obtained the final logistic regression model with five independent risk factors at the start of RRT: a high APACHE III score (OR: 1.228, 95% CI: 1.079-1.397), high VIS (OR: 1.147, 95% CI: 1.021-1.290), low mean arterial pressure (MAP) (OR: 1.170, 95% CI: 1.050-1.303), high lactate value (OR: 1.552, 95% CI: 1.032-2.333), and long time from AKI to initiation of RRT (OR: 1.014, 95% CI: 1.002-1.027). Conclusion: In this study, we showed that at the start of RRT, the APACHE III score and the VIS can accurately predict the risk of death in patients undergoing continuous RRT for CS-AKI. The APACHE III score on the first postoperative day allows early prediction of patient mortality risk. Predictors influencing patient mortality at the initiation of RRT were high APACHE III score, high VIS, low MAP, high lactate value, and long time from AKI to the start of RRT.

Rapid 500 mL albumin bolus versus rapid 200 mL bolus followed by slower continuous infusion in post-cardiac surgery patients: a pilot before-and-after study

Objective: To evaluate the haemodynamic effects of rapid fluid bolus therapy (FBT) (500 mL of 4% albumin over several minutes) versus combined FBT (rapid 200 mL FBT followed by a 300 mL infusion over 30 minutes). Design: Single centre, prospective, before-and-after trial. Setting: A tertiary intensive care unit in Australia. Participants: Fifty mechanically ventilated post-cardiac surgery patients. Interventions: Rapid 4% albumin FBT versus combined FBT. Main outcome measures: We recorded haemodynamic parameters from before FBT to 30 minutes after FBT. A mean arterial pressure (MAP) response was defined by a MAP increase > 10%, and a cardiac index (CI) response was defined by a CI increase > 15%. Results: Immediately after rapid FBT versus combined FBT, there was a CI response in 13 patients (52%) compared with five patients (20%) respectively (P = 0.038), and a MAP response in 11 patients (44%) in each group. However, from FBT administration to 30 minutes, there was a time and group interaction such that MAP was higher in the rapid FBT group (P = 0.003), as was the case for central venous pressure (P = 0.002) and mean pulmonary artery pressure (P < 0.001). Body temperature fell immediately and was lower with rapid FBT but became warmer than with combined FBT later (P < 0.001). At 30 minutes, a MAP response was seen in ten patients (40%) compared with nine patients (36%) (P < 0.99) and a CI response was present in eight patients (32%) compared with 11 patients (44%) (P = 0.56) in the rapid versus combined FBT groups respectively. Conclusion: Rapid FBT was superior to combined FBT in terms of mean MAP levels and immediate CI response. However, the number of MAP responders or CI responders was similar at 30 minutes.

Postoperative hemodynamics after high spinal block with or without intrathecal morphine in cardiac surgical patients: a randomized-controlled trial

PURPOSE

There is some evidence for the use of intrathecal morphine as a means to provide prolonged analgesia in selective cardiac surgical patients; however, the hemodynamic effects of intrathecal morphine are not well defined. This study was designed to study the effect of intrathecal morphine on hemodynamic parameters in cardiac surgery patients.

METHODS

In a prospective, double-blind study, 100 adult cardiac surgical patients were randomized to receive either intrathecal 40 mg of 0.5% hyperbaric bupivacaine alone (intrathecal bupivacaine [ITB] group, n = 50) or intrathecal 250 µg of morphine added to 40 mg of 0.5% bupivacaine (intrathecal bupivacaine and morphine [ITBM] group, n = 50). Hemodynamic data, pain scores, rescue analgesic use, spirometry, and vasopressor use were recorded every four hours after surgery for 48 hr. The primary outcome was the incidence of vasoplegia in each group, which was defined as a cardiac index > 2.2 L·min-1·m-2 with the requirement of vasopressors to maintain the mean arterial pressure > 60 mmHg with the hemodynamic episode lasting > four hours.

RESULTS

Eighty-seven patients were analyzed (ITB group, n = 42, and ITBM group, n =45). The incidence of vasoplegia was higher in the ITBM group than in the ITB group [14 (31%) vs 5 (12%), respectively; relative risk, 2.6; 95% confidence interval [CI], 1.0 to 6.6; P = 0.04]. The mean (standard deviation [SD]) duration of vasoplegia was significantly longer in the ITBM group than in the ITB group [8.9 (3.0) hr vs 4.3 (0.4) hr, respectively; difference in means, 4.6; 95% CI, 3.7 to 5.5; P < 0.001].

CONCLUSION

Intrathecal morphine added to bupivacaine for high spinal anesthesia increases the incidence and duration of vasoplegia in cardiac surgery patients.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT02825056); registered 19 June 2016.

Defining Vasoplegia Following Durable, Continuous Flow Left Ventricular Assist Device Implantation

This study aimed to develop a definition of vasoplegia that reliably predicts clinical outcomes. Vasoplegia was evaluated using data from the electronic health record for each 15-minute interval for 72 hours following cardiopulmonary bypass. Standardized definitions considered clinical features (systemic vascular resistance [SVR], mean arterial pressure [MAP], cardiac index [CI], norepinephrine equivalents [NEE]), threshold strategy (criteria occurring in any versus all measurements in an interval), and duration (criteria occurring over multiple consecutive versus separated intervals). Minor vasoplegia was MAP < 60 mm Hg or SVR < 800 dynes⋅sec⋅cm with CI > 2.2 L/min/m and NEE ≥ 0.1 µg/kg/min. Major vasoplegia was MAP < 60 mm Hg or SVR < 700 dynes⋅sec⋅cm with CI > 2.5 L/min/m and NEE ≥ 0.2 µg/kg/min. The primary outcome was incidence of vasoplegia for eight definitions developed utilizing combinations of these criteria. Secondary outcomes were associations between vasoplegia definitions and three clinical outcomes: time to extubation, time to intensive care unit discharge, and nonfavorable discharge. Minor vasoplegia detected anytime within a 15-minute period (MINOR_ANY_15) predicted the highest incidence of vasoplegia (61%) and was associated with two of three clinical outcomes: 1 day delay to first extubation (95% CI: 0.2 to 2) and 7 day delay to first intensive care unit discharge (95% CI: 1 to 13). The MINOR_ANY_15 definition should be externally validated as an optimal definition of vasoplegia.

Temperature and haemodynamic effects of a 100 mL bolus of 20% albumin at room versus body temperature in cardiac surgery patients

Objective: To study the temperature and haemodynamic effects of room versus body temperature 20% albumin fluid bolus therapy (FBT). Design: Single-centre, prospective, before-after trial. Setting: A tertiary intensive care unit (ICU) in Australia. Participants: Sixty ventilated post-cardiac surgery patients. Intervention: Room versus body temperature 100 mL 20% albumin FBT. Main outcome measures: We recorded haemodynamic data from FBT start to 30 minutes after FBT. The cardiac index (CI) response was defined by a CI increase > 15%, and the mean arterial pressure (MAP) response was defined by a MAP increase > 10%. Outcomes: Immediately after FBT, median blood temperature decreased by -0.1°C (interquartile range [IQR], -0.1 to 0.0°C) with room temperature albumin versus 0.0°C (IQR, -0.1 to 0.0°C) with body temperature albumin (P < 0.001). The CI or MAP responses were similar. There was, however, a time and study group interaction for blood temperature (P < 0.001) for absolute and relative changes. In addition, mean pulmonary arterial pressure (PAP) (P = 0.002) increased more with body temperature albumin and remained higher for most of the observation period. Conclusion: Compared with room temperature albumin FBT, body temperature 20% albumin FBT prevents FBT-associated blood temperature fall and increases mean PAP. However, CI and MAP changes were the similar between the two groups, implying that fluid temperature has limited haemodynamic effects in these patients.

Cardiac and Vascular α1-Adrenoceptors in Congestive Heart Failure: A Systematic Review

As heart failure (HF) is a devastating health problem worldwide, a better understanding and the development of more effective therapeutic approaches are required. HF is characterized by sympathetic system activation which stimulates α- and β-adrenoceptors (ARs). The exposure of the cardiovascular system to the increased locally released and circulating levels of catecholamines leads to a well-described downregulation and desensitization of β-ARs. However, information on the role of α-AR is limited. We have performed a systematic literature review examining the role of both cardiac and vascular α1-ARs in HF using 5 databases for our search. All three α1-AR subtypes (α1A, α1B and α1D) are expressed in human and animal hearts and blood vessels in a tissue-dependent manner. We summarize the changes observed in HF regarding the density, signaling and responses of α1-ARs. Conflicting findings arise from different studies concerning the influence that HF has on α1-AR expression and function; in contrast to β-ARs there is no consistent evidence for down-regulation or desensitization of cardiac or vascular α1-ARs. Whether α1-ARs are a therapeutic target in HF remains a matter of debate.

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.

Vasoplegia after cardiopulmonary bypass: A narrative review of pathophysiology and emerging targeted therapies

Cardiovascular disease remains the leading cause of death in the United States, and cardiopulmonary bypass is a cornerstone in the surgical management of many related disease states. Pathophysiologic changes associated both with extracorporeal circulation and shock can beget a syndrome of low systemic vascular resistance paired with relatively preserved cardiac output, termed vasoplegia. While increased vasopressor requirements accompany vasoplegia, related pathophysiologic mechanisms may also lead to true catecholamine resistance, which is associated with further heightened mortality. The introduction of a second non-catecholamine vasopressor, angiotensin II, and non-specific nitric oxide scavengers offers potential means by which to manage this challenging phenomenon. This narrative review addresses both the definition, risk factors, and pathophysiology of vasoplegia and potential therapeutic interventions.

Comparison of the Hemodynamic and Temperature Effects of a 500-mL Bolus of 4% Albumin at Room Versus Body Temperature in Cardiac Surgery Patients

OBJECTIVE

To compare the hemodynamic effect of room temperature (cold) 4% albumin fluid bolus therapy (FBT) with body temperature (warm) albumin FBT.

DESIGN

Prospective, before-after trial.

SETTING

A tertiary intensive care unit (ICU).

PARTICIPANTS

Sixty ventilated, post-cardiac surgery patients prescribed with 4% albumin FBT.

INTERVENTION

Cold or warm 4% albumin 500 ml FBT.

MEASUREMENTS AND MAIN RESULTS

We recorded hemodynamic parameters before and for 30 minutes after FBT. Cardiac index (CI) and mean arterial pressure (MAP) responses were defined by a CI increase >15% and a MAP increase >10%, respectively. Immediately after FBT, median [interquartile range] core temperature changed by -0.3 [-0.4; -0.3] °C with cold albumin vs. 0.0 [0.0; 0.1]°C with warm albumin (P<0.001). The median CI increase was 0.3 [0.0; 0.5] L/min/m2 with 14 CI-responders (47%) in both groups (P>0.99). The median immediate MAP increase was 9 [3; 15] mmHg with cold albumin vs. 11 [5; 13] mmHg with warm albumin (P=0.79), with a MAP-response in 16 vs. 17 patients (P=0.99). There was an interaction between group and time for MAP (P=0.002), mean pulmonary artery pressure (PAP) (P=0.002) and core temperature (P<0.001). In the cold albumin group, after the initial response, MAP and mean PAP decreased more slowly than with warm albumin and, after the initial fall, core temperature increased toward baseline.

CONCLUSION

In postoperative cardiac surgery patients, warm albumin FBT prevents the decrease in core temperature and, after an initial similar increase, is associated with a faster return of MAP and mean PAP toward baseline.

Vasoplegic syndrome following cardiothoracic surgery-review of pathophysiology and update of treatment options

Vasoplegic syndrome is a common occurrence following cardiothoracic surgery and is characterized as a high-output shock state with poor systemic vascular resistance. The pathophysiology is complex and includes dysregulation of vasodilatory and vasoconstrictive properties of smooth vascular muscle cells. Specific bypass machine and patient factors play key roles in occurrence. Research into treatment of this syndrome is limited and extrapolated primarily from that pertaining to septic shock, but is evolving with the expanded use of catecholamine-sparing agents. Recent reports demonstrate potential benefit in novel treatment options, but large clinical trials are needed to confirm.

Longer term hemodialysis-dependent chronic renal failure increases the risk of post-cardiac surgery vasoplegic syndrome

PURPOSE

We evaluated whether longer term hemodialysis (HD) is associated with a higher incidence of vasoplegic syndrome (VS) after cardiac surgery.

METHODS

This retrospective, single-center cohort study included 562 consecutive patients who underwent cardiac surgery in a tertiary hospital from January 2015 to December 2016. We assessed VS occurrence and its relationship with HD duration and other risk factors. To assess the effect of the HD duration on VS occurrence, we constructed ordinal variables: HD = 0 (non-HD), 0 < HD ≤ 5 (HD ≤ 5 years), 5 < HD ≤ 10, and 10 < HD.

RESULTS

The overall mean (± standard deviation) age of patients was (73 ± 11) years, and there were 60.9% men. Forty-one patients (7.3%) were HD dependent. Cardiac surgeries included all coronary artery bypass graft procedures, all valvular procedures, and aortic surgery involving cardiopulmonary bypass (CPB). Sixty-six patients (10%) developed VS. Most preoperative patient characteristics were comparable between the VS and no-VS groups; a chronic HD status and a total CPB time of > 180 min were significantly more common in the VS group (P < 0.0001 and P = 0.02, respectively). Longer term HD significantly correlated with VS incidence (P < 0.0001). Ordinal variables for the HD duration and age and known risk factors for VS (preoperative use of angiotensin-converting enzyme inhibitors and beta-blockers, low left-ventricular ejection fraction, and CPB time > 180 min) were subjected to multivariate regression analysis. Long-term HD was identified as an independent predictor of VS (odds ratio, 2.29, 95% confidence interval, 1.66-3.18).

CONCLUSIONS

Longer term HD may be associated with a higher VS incidence after cardiac surgery. VS should be given attention after cardiac surgery in chronic HD-dependent patients.

Comparison of Angiotensin-Converting Enzyme Inhibitor and Angiotensin Receptor Blocker Management Strategies Before Cardiac Surgery: A Pilot Randomized Controlled Registry Trial

Background

Postoperative clinical outcomes associated with the preoperative continuation or discontinuation of angiotensin‐converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) before cardiac surgery remain unclear.

Methods and Results

In a single‐center, open‐label, randomized, registry‐based clinical trial, patients undergoing nonemergent cardiac surgery were assigned to ACEI/ARB continuation or discontinuation 2 days before surgery. Among the 584 patients screened, 261 met study criteria and 126 (48.3%) patients were enrolled. In total,121 patients (96% adherence; 60 to continuation and 61 to ACEI/ARB discontinuation) underwent surgery and completed the study protocol, and follow‐up was 100% complete. Postoperative intravenous vasopressor use (78.3% versus 75.4%, P=0.703), vasodilator use (71.7% versus 80.3%, P=0.265), vasoplegic shock (31.7% versus 27.9%, P=0.648), median duration of vasopressor (10 versus 5 hours, P=0.494), and vasodilator requirements (10 versus 9 hours, P=0.469) were not significantly different between the continuation and discontinuation arms. No differences were observed in the incidence of acute kidney injury (1.7% versus 1.6%, P=0.991), stroke (no events, mortality (1.7% versus 1.6%, P=0.991), median duration of mechanical ventilation (6 versus 6 hours, P=0.680), and median intensive care unit length of stay (43 versus 27 hours, P=0.420) between the treatment arms.

Conclusions

A randomized study evaluating the routine continuation or discontinuation of ACEIs or ARBs before cardiac surgery was feasible, and treatment assignment was not associated with differences in postoperative physiological or clinical outcomes. These preliminary findings suggest that preoperative ACEI/ARB management strategies did not affect the postoperative course of patients undergoing cardiac surgery.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02096406.

Factors Affecting Cardiovascular Physiology in Cardiothoracic Surgery: Implications for Lumped-Parameter Modeling

Cardiothoracic surgeries are complex procedures during which the patient cardiovascular physiology is constantly changing due to various factors. Physiological changes begin with the induction of anesthesia, whose effects remain active into the postoperative period. Depending on the surgery, patients may require the use of cardiopulmonary bypass and cardioplegia, both of which affect postoperative physiology such as cardiac index and vascular resistance. Complications may arise due to adverse reactions to the surgery, causing hemodynamic instability. In response, fluid resuscitation and/or vasoactive agents with varying effects may be used in the intraoperative or postoperative periods to improve patient hemodynamics. These factors have important implications for lumped-parameter computational models which aim to assist surgical planning and medical device evaluation. Patient-specific models are typically tuned based on patient clinical data which may be asynchronously acquired through invasive techniques such as catheterization, during which the patient may be under the effects of drugs such as anesthesia. Due to the limited clinical data available and the inability to foresee short-term physiological regulation, models often retain preoperative parameters for postoperative predictions; however, without accounting for the physiologic changes that may occur during surgical procedures, the accuracy of these predictive models remains limited. Understanding and incorporating the effects of these factors in cardiovascular models will improve the model fidelity and predictive capabilities.

Evaluation of Vasopressin for Vasoplegic Shock in Patients With Preoperative Left Ventricular Dysfunction After Cardiac Surgery: A Propensity-Score Analysis

PURPOSE

Postoperative vasoplegic shock after cardiac surgery seems to be a frequent complication with poor outcomes. We hypothesized that vasopressin may increase the risk of poor outcomes in patients with preoperative Left Ventricular Dysfunction (pLVD) rather than norepinephrine. The aim of this study was to assess whether vasopressin is superior to norepinephrine to improve outcomes in patients with pLVD after cardiac surgery.

METHODS

This retrospective cohort study included 1,156 patients with postoperative vasoplegic shock (mean arterial pressure <65 mmHg resistant to fluid challenge and cardiac index >2.20 L/min m) and pLVD (left ventricular ejection fraction ≤35%, left ventricular end-diastolic diameter ≥60 mm, New York Heart Association ≥III) from 2007 to 2017. To address any indicated biases, we derived a propensity score predicting the functions of vasopressin (0.02-0.07 U/min) and norepinephrine (10-60 μg/min) on postoperative vasoplegic shock. The primary outcomes were 30-day mortality, mechanical ventilation more than 48 h, cardiac reoperation, extracorporeal membrane oxygenation, stroke, and acute kidney injury, whereas the secondary outcomes included infection, septic shock, atrial fibrillation and ventricular arrhythmias.

RESULTS

There were 338 patients (169 vasopressin and169 norepinephrine) with a similar risk profile in propensity score-matched cohort. In propensity-matched patients, the primary outcomes of vasopressin and norepinephrine showed no significant difference (50.89% vs. 58.58%, P = 0.155). However, compared with norepinephrine, secondary outcomes of vasopressin were increased due to the high rate of atrial fibrillation (11.83% vs. 20.12%, P = 0.038) and ventricular arrhythmias (14.20% vs. 24.85%, P = 0.014).

CONCLUSIONS

Compared with norepinephrine, vasopressin could not improve the postoperative outcomes in patients with pLVD after cardiac surgery. Vasopressin should be cautious to be used as a first-line vasopressor agent in postcardiac vasoplegic shock.

Intraoperative vasoplegic syndrome in patients with fulminant myocarditis on ventricular assist device placement

PURPOSE

Fulminant myocarditis is uncommon, but life-threatening, and some patients need mechanical circulatory support. This study was performed to evaluate how different types of mechanical circulatory support-biventricular assist device (BiVAD) or left ventricular assist device (LVAD) placement-affect intraoperative hemodynamic status.

METHODS

From January 2013 to September 2016, the patients who underwent BiVAD or LVAD placement for fulminant myocarditis were analyzed. The mean arterial pressure (MAP), mean pulmonary arterial pressure, central venous pressure (CVP), vasoactive score, and inotropic score were recorded at five time points: after the induction of anesthesia; at weaning, 30 min after weaning, and 60 min after weaning from cardiopulmonary bypass (CPB); and at the end of surgery. The vasoactive and inotropic scores were calculated as follows: vasoactive score = norepinephrine (µg/kg/min) × 100 + milrinone (µg/kg/min) × 10 + olprinone (µg/kg/min) × 25: inotropic score = dopamine (µg/kg/min) × 1 + dobutamine (µg/kg/min) × 1 + epinephrine (µg/kg/min) × 100.

RESULTS

We enrolled 16 patients of fulminant myocarditis. Ten of them underwent BiVAD placement, and the other underwent LVAD placement. After weaning from CPB, the BiVAD group had a significantly lower MAP but no difference in CVP. The vasoactive score was significantly higher in the BiVAD group at weaning of CPB (p = 0.015), 30 min after weaning (p = 0.004), 60 min after weaning (p = 0.005), and at the end of surgery (p < 0.016).

CONCLUSION

Patients with BiVAD placement required more vasoactive support to maintain optimal hemodynamic status compared with those with LVAD placement. This result indicates that BiVAD placement was more associated with vasoplegic syndrome.

Vasoplegia after implantation of a continuous flow left ventricular assist device: incidence, outcomes and predictors

Background

Vasoplegia after routine cardiac surgery is associated with severe postoperative complications and increased mortality. It is also prevalent in patients undergoing implantation of pulsatile flow left ventricular assist devices (LVAD). However, less is known regarding vasoplegia after implantation of newer generations of continuous flow LVADs (cfLVAD). We aim to report the incidence, impact on outcome and predictors of vasoplegia in these patients.

Methods

Adult patients scheduled for primary cfLVAD implantation were enrolled into a derivation cohort (n = 118, 2006–2013) and a temporal validation cohort (n = 73, 2014–2016). Vasoplegia was defined taking into consideration low mean arterial pressure and/or low systemic vascular resistance, preserved cardiac index and high vasopressor support. Vasoplegia was considered after bypass and the first 48 h of ICU stay lasting at least three consecutive hours. This concept of vasoplegia was compared to older definitions reported in the literature in terms of the incidence of postoperative vasoplegia and its association with adverse outcomes. Logistic regression was used to identify independent predictors. Their ability to discriminate patients with vasoplegia was quantified by the area under the receiver operating characteristic curve (AUC).

Results

The incidence of vasoplegia was 33.1% using the unified definition of vasoplegia. Vasoplegia was associated with increased ICU length-of-stay (10.5 [6.9–20.8] vs 6.1 [4.6–10.4] p = 0.002), increased ICU-mortality (OR 5.8, 95% CI 1.9–18.2) and one-year-mortality (OR 3.9, 95% CI 1.5–10.2), and a higher incidence of renal failure (OR 4.3, 95% CI 1.8–10.4). Multivariable analysis identified previous cardiothoracic surgery, preoperative dopamine administration, preoperative bilirubin levels and preoperative creatinine clearance as independent preoperative predictors of vasoplegia. The resultant prediction model exhibited a good discriminative ability (AUC 0.80, 95% CI 0.71–0.89, p <  0.01). Temporal validation resulted in an AUC of 0.74 (95% CI 0.61–0.87, p <  0.01).

Conclusions

In the era of the new generation of cfLVADs, vasoplegia remains a prevalent (33%) and critical condition with worse short-term outcomes and survival. We identified previous cardiothoracic surgery, preoperative treatment with dopamine, preoperative bilirubin levels and preoperative creatinine clearance as independent predictors.

Electronic supplementary material

The online version of this article (10.1186/s12871-018-0645-y) contains supplementary material, which is available to authorized users.

Definitions and pathophysiology of vasoplegic shock

Vasoplegia is the syndrome of pathological low systemic vascular resistance, the dominant clinical feature of which is reduced blood pressure in the presence of a normal or raised cardiac output. The vasoplegic syndrome is encountered in many clinical scenarios, including septic shock, post-cardiac bypass and after surgery, burns and trauma, but despite this, uniform clinical definitions are lacking, which renders translational research in this area challenging. We discuss the role of vasoplegia in these contexts and the criteria that are used to describe it are discussed. Intrinsic processes which may drive vasoplegia, such as nitric oxide, prostanoids, endothelin-1, hydrogen sulphide and reactive oxygen species production, are reviewed and potential for therapeutic intervention explored. Extrinsic drivers, including those mediated by glucocorticoid, catecholamine and vasopressin responsiveness of the blood vessels, are also discussed. The optimum balance between maintaining adequate systemic vascular resistance against the potentially deleterious effects of treatment with catecholamines is as yet unclear, but development of novel vasoactive agents may facilitate greater understanding of the role of the differing pathways in the development of vasoplegia. In turn, this may provide insights into the best way to care for patients with this common, multifactorial condition.

Post cardiac surgery stunning reduces stroke work, but leaves cardiac power output unchanged in patients with normal ejection fraction

This study assesses positional changes in cardiac power output and stroke work compared with classic hemodynamic variables, measured before and after elective coronary artery bypass graft surgery. The hypothesis was that cardiac power output was altered in relation to cardiac stunning. The study is a retrospective analysis of data from two previous studies performed in a tertiary care university hospital. Thirty-six patients scheduled for elective coronary artery bypass graft surgery, with relatively preserved left ventricular function, were included. A pulmonary artery catheter and a radial artery catheter were placed preoperatively. Cardiac power output and stroke work were calculated through thermodilution both supine and standing prior to induction of anesthesia and again day one postoperatively. Virtually all systemic hemodynamic parameters changed significantly from pre- to postoperatively, and from supine to standing. Cardiac power output was maintained at 0.9-1.0 (±0.3) W both pre- and postoperatively and from supine to standing on both days. Stroke work fell from pre- to postoperatively from 1.1 to 0.8 J (P < 0.001), there was a significant fall in stroke work with positional change preoperatively from 1.1 to 0.9 J (P < 0.001). Postoperatively the stroke work remained at 0.8 J despite positional change. Cardiac power output was the only systemic hemodynamic variable which remained unaltered during all changes. Stroke work appears to be a more sensitive marker for temporary cardiovascular dysfunction than cardiac power output. Further studies should explore the relationship between stroke work and cardiac performance and whether cardiac power output is an autoregulated intrinsic physiological parameter.

Early negative fluid balance is associated with lower mortality after cardiovascular surgery

BACKGROUND

Early fluid expansion could prevent postoperative organ hypoperfusion. However, excessive fluid resuscitation adversely influences multiple organ systems. This retrospective, observational study aimed to investigate the relationship between early negative fluid balance and postoperative mortality in critically ill adult patients following cardiovascular surgery.

METHODS

In total, 567 critically ill patients who had undergone cardiovascular surgery and whose intensive care unit length of stay (LOS) was more than 24 hours were enrolled. The baseline characteristics, daily fluid balance and cumulative fluid balance were obtained. Patients were followed until discharge or day 28. Multivariate logistic regressions adjusted by propensity score were used to analyze the relationship between early negative fluid balance and postoperative mortality.

RESULTS

Overall, postoperative mortality was 6.2% (35/567). Acute Physiology and Chronic Health Evaluation II on admission (odd ratios [OR] 1.110), acute kidney injury stage (OR 1.639) and renal replacement therapy received (OR 3.922) were the independent risk factors of postoperative mortality, whereas negative daily fluid balance at day 2 (OR 0.411) was the protective factor. Patients with a negative daily fluid balance at day 2 had lower postoperative mortality (3.4% vs. 12.2% in the positive fluid balance group), lower acute kidney injury (AKI) stage, were less likely to receive renal replacement therapy (RRT) and experienced shorter hospital LOS compared with those with a daily positive fluid balance.

CONCLUSION

This retrospective, observational study indicates that early negative fluid balance is associated with lower postoperative mortality in critically ill patients following cardiovascular surgery. Further prospective, randomized trials are needed to prove the benefits from the restrictive fluid management strategy.

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.

Vitamin D and Postoperative Vasopressor Use in Cardiopulmonary Bypass

The use of cardiopulmonary bypass (CPB) in cardiac surgery often leads to a systemic inflammatory response. Up to 25% of patients undergoing CPB for cardiac surgery are reported to develop vasoplegic syndrome in the acute postoperative period, in which the patients are refractory to vasopressors. The purpose of this study is to assess vitamin D deficiency as a risk factor for vasoplegia after using CPB. We performed a retrospective review of 1322 patients undergoing adult cardiac surgery requiring CPB. Forty-six patients with previously recorded 25-hydroxy vitamin D (25(OH)D) levels within 6 months of surgery met the conditions of this study. The mean level of 25(OH)D was 32.7 ng/mL (standard deviation [SD] = 15.1). The mean age of patients was 67 (SD = 10.1) years old, most were male (63%) and white (78%). Average CPB time was 140 ± 44 minutes. Postoperative vasopressor use was compared to individual preoperative 25(OH)D levels. As a secondary end point, postoperative vasopressor use and vasoplegia were analyzed between 3 groups: Vitamin D deficient defined as 25(OH)D ≤20 ng/mL (n = 7), vitamin D insufficient defined as 25(OH)D between 20 and 29 ng/mL (n = 15), and vitamin D sufficient defined as 25(OH)D ≥30 ng/mL (n = 24). There was no correlation between vitamin D levels and postoperative vasopressor use. The mean doses of postoperative vasopressor use were 0.088 µg/kg/min (standard error of the mean [SEM] = 0.032), 0.085 µg/kg/min (SEM = 0.037), and 0.072 µg/kg/min (SEM = 0.024) of norepinephrine equivalents for the vitamin D deficient, insufficient, and sufficient groups, respectively. Incidence of vasoplegia for each group was the following: 0.143 for vitamin D deficient, 0.067 for vitamin D insufficient, and 0.125 for vitamin D sufficient. In this pilot study, there does not appear to be a relationship between vitamin D and vasopressor use following cardiac surgery utilizing CPB; however, there appears to be a trend toward an increased vasopressor usage in patients with decreased vitamin D levels. A larger sample size and a prospective analysis are warranted to further assess the significance of the relationship between vasoplegia and vitamin D deficiency. With further investigation, vitamin D has the potential to become a low-cost, low-risk therapeutic for improving outcomes in CPB surgery.

Impact of intraoperative cytokine adsorption on outcome of patients undergoing orthotopic heart transplantation-an observational study

AIM

The aim of this study was to assess the influence of intraoperative cytokine adsorption on the perioperative vasoplegia, inflammatory response and outcome during orthotopic heart transplantation (OHT).

METHODS

Eighty-four OHT patients were separated into the cytokine adsorption (CA)-treated group or controls. Vasopressor demand, inflammatory response described by procalcitonin and C-reactive protein, and postoperative outcome were assessed performing propensity score matching.

RESULTS

In the 16 matched pairs, the median noradrenaline requirement was significantly less in the CA-treated patients than in the controls on the first and second postoperative days (0.14 vs 0.3 μg*kg^-1 *min^-1 , P = .039 and 0.06 vs 0.32 μg*kg^-1 *min^-1 , P = .047). The inflammatory responses were similar in the two groups. There was a trend toward shorter length of mechanical ventilation and intensive care unit (ICU) stay in the CA-treated group compared to the controls. No difference in adverse events was observed between the two groups. The frequency of renal replacement therapy was less in the CA‐treated patients than in the controls.

CONCLUSIONS

Intraoperative CA treatment was associated with reduced vasopressor demand with a favorable tendency in length of mechanical ventilation, ICU stay and renal replacement therapy. CA treatment was not linked to higher rates of adverse events.

Vasoplegia after heart transplantation: outcomes at 1 year

OBJECTIVES

Vasoplegia syndrome is a potentially life-threatening condition that can occur following cardiopulmonary bypass. Heart transplantation is a recognized risk factor for developing this vasodilatory state. The objective of this study was to determine the effects of vasoplegia syndrome on 1-year heart transplant outcomes.

METHODS

A retrospective review of orthotopic heart transplants at a single institution between November 2010 and December 2014 was performed. Of the 347 consecutive adult patients, 107 patients (30.8%) met criteria for vasoplegia syndrome. Preoperative factors and intraoperative variables were collected and compared between vasoplegia and non-vasoplegia cohorts. The incidence of postoperative complications, transplant rejection and patient survival within 1 year were evaluated.

RESULTS

Demographics and preoperative medication profiles were similar in both groups, while mechanical circulatory support device use was associated with vasoplegia syndrome (30.8% vs 20.0%; P = 0.039). Perioperative characteristics such as longer cardiopulmonary bypass [165.0 (interquartile range [IQR] 74) min vs 140.0 (IQR 42.7) min; P < 0.001] and increased blood product usage (24.7 ± 17.2 units vs 17.7 ± 14.3 units; P < 0.001) were associated with vasoplegia. Non-vasoplegia patients were more likely to be extubated [42.9 (IQR 37.3) h vs 66.8 (IQR 50.2) h; P < 0.001] and discharged earlier [10.0 (IQR 6) days vs 14.0 (IQR 11.5) days; P < 0.001]. One-year patient survival (92.0% vs 88.6%; P = 0.338) and any-treated rejection rates (82.7% vs 84.3%; P = 0.569) were not significantly different between groups.

CONCLUSIONS

Although vasoplegia syndrome was associated with an increase in perioperative morbidity, including greater mechanical ventilation time and hospital length of stay, no significant differences in survival or allograft rejection at 1 year was demonstrated.

Anesthetic management of the patient undergoing heart transplantation

Cardiac transplantation is the treatment of choice for patients with end-stage heart failure. Over the years, significant advances in patient selection, donor optimization and selection, and optimization of immunosuppression strategies have markedly improved outcomes. In this review, we highlight patient selection, donor management and procurement, heart transplantation procedure, and intraoperative and postoperative management of heart transplants.