Rationale and design of the steroids in cardiac surgery trial

Pulmonary reperfusion injury in post-palliative intervention of oligaemic cyanotic CHD: a new catastrophic consequence or just revisiting the same old story?

Pulmonary reperfusion injury is a well-recognised clinical entity in the setting pulmonary artery angioplasty for pulmonary artery stenosis or chronic thromboembolic disease, but not much is known about this complication in post-palliative intervention of oligaemic cyanotic CHD. The pathophysiology of pulmonary reperfusion injury in this population consists of both ischaemic and reperfusion injury, mainly resulting in oxidative stress from reactive oxygen species generation, followed by endothelial dysfunction, and cytokine storm that may induce multiple organ dysfunction. Other mechanisms of pulmonary reperfusion injury are "no-reflow" phenomenon, overcirculation from high pressure in pulmonary artery, and increased left ventricular end-diastolic pressure. Chronic hypoxia in cyanotic CHD eventually depletes endogenous antioxidant and increased the risk of pulmonary reperfusion injury, thus becoming a concern for palliative interventions in the oligaemic subgroup. The incidence of pulmonary reperfusion injury varies depending on multifactors. Despite its inconsistence occurrence, pulmonary reperfusion injury does occur and may lead to morbidity and mortality in this population. The current management of pulmonary reperfusion injury is supportive therapy to prevent deterioration of lung injury. Therefore, a general consensus on pulmonary reperfusion injury is necessary for the diagnosis and management of this complication as well as further studies to establish the use of novel and potential therapies for pulmonary reperfusion injury.

Lung injury after cardiopulmonary bypass: Alternative treatment prospects

Although the lung injury caused by cardiopulmonary bypass (CPB) has been extensively investigated, the incidence and mortality of lung injury after CPB remain a prominent clinical problem. The poor outcome has been attributed to multifactorial etiology, including the systemic inflammatory response and ischemia reperfusion (I/R) injury during CPB. Lung injury after CPB is a complex pathophysiological process and has many clinical manifestations of mild to severe disease. Which is associated with prognosis. To alleviate this lung injury, interventions that address the pathogenesis are particularly important. This review summarizes the pathogenesis, mechanism and treatment options of lung injury after CPB, such as lung protection with intralipid.

Insight into atrial fibrillation through analysis of the coding transcriptome in humans

Atrial fibrillation is the most common sustained cardiac arrhythmia in humans, and its prevalence continues to increase because of the aging of the world population. Much still needs to be learned about the molecular pathways involved in the development and the persistence of the disease. Analysis of the transcriptome of cardiac tissue has provided valuable insight into diverse aspects of atrial remodeling, in particular concerning electrical remodeling-related to ion channels-and structural remodeling identified by dysregulation of processes linked to inflammation, fibrosis, oxidative stress, and thrombogenesis. The huge amount of data produced by these studies now represents a valuable source for the identification of novel potential therapeutic targets. In addition, the shift from cardiac tissue to peripheral blood as a substrate for transcriptome analysis revealed this strategy as a promising tool for improved diagnosis and therefore better patient care.

Definitions of post-coronary artery bypass grafting myocardial infarction: variations in incidence and prognostic significance

OBJECTIVES

Using data from the CORONARY trial (n = 4752), we evaluated the incidence and prognostic significance of myocardial infarction (MI) applying different definitions based on peak postoperative creatine kinase-MB isoenzyme and cardiac troponin levels. We then aimed to identify the peak cardiac troponin during the first 3 postoperative days that was independently associated with a 2-fold increase in 30-day mortality.

METHODS

To combine different assays, we analysed cardiac troponins in multiples of their respective upper limit of normal (ULN). We identified the lowest threshold with a hazard ratio (HR) >2 for 30-day mortality independent of EuroSCORE and on- versus off-pump surgery.

RESULTS

Depending on the definition used based on creatine kinase-MB, the incidence of MI after coronary artery bypass grafting (CABG) ranged from 0.6% to 19% and the associated HRs for 30-day mortality ranged from 2.7 to 6.9. Using cardiac troponin (1528 patients), the incidence of MI ranged from 1.7% to 13% depending on the definition used with HRs for 30-day mortality ranging from 5.1 to 7.2. The first cardiac troponin threshold we evaluated, 180xULN, was associated with an adjusted HR for 30-day mortality of 7.6 [95% confidence interval (CI) 3.4-17.1] when compared to <130xULN. The next independent threshold was 130xULN with an adjusted HR for 30-day mortality of 7.8 (95% CI 2.3-26.1). The next cardiac troponin tested threshold (70xULN) did not meet criteria for significance.

CONCLUSIONS

Our results illustrate that the incidence and prognosis of a post-CABG MI varies based on the definition used. Validated post-CABG MI diagnostic criteria formulated from their independent association with important clinical outcomes are needed.

Methylprednisolone Does Not Reduce Acute Postoperative Pain After Cardiac Surgery: Subanalysis of a Randomized Clinical Trial

BACKGROUND

Pain after cardiac surgery is largely treated with opioids, but their poor safety profile makes nonopioid medications attractive as part of multimodal pathways. Anti-inflammatory drugs reduce acute postoperative pain, but the role of steroids in reducing acute poststernotomy pain is unclear. We evaluated the association between the intraoperative administration of methylprednisolone and postoperative analgesia, defined as a composite of pain scores and opioid consumption, during the initial 24 hours after cardiac surgery.

METHODS

We conducted a post hoc retrospective analysis of a large clinical trial in which adults having cardiac surgery were randomized 1:1 to receive 2 intraoperative doses of 250 mg IV methylprednisolone or placebo. Pain scores and opioid consumption were collected during the initial 24 hours after surgery. Methylprednisolone was considered to be associated with better pain control than placebo if proven noninferior (not worse) on both pain scores (defined a priori with delta of 1 point) and opioid consumption (delta of 20%) and superior to placebo in at least 1 of the 2 outcomes. This test was repeated in the opposite direction (testing whether placebo is better than methylprednisolone on postoperative pain management).

RESULTS

Of 251 eligible patients, 127 received methylprednisolone and 124 received placebo. Methylprednisolone was noninferior to placebo on pain with difference in mean (CI) pain scores of -0.25 (-0.71 to 0.21); P < .001. However, methylprednisolone was not noninferior to placebo on opioid consumption (ratio of geometric means [CI]: 1.11 [0.64-1.91]; P = .37). Because methylprednisolone was not noninferior to placebo on both outcomes, we did not proceed to superiority testing based on the a priori stopping rules. Similar results were found when testing the opposite direction.

CONCLUSIONS

In this post hoc analysis, we could not identify a beneficial analgesic effect after cardiac surgery associated with methylprednisolone administration. There are currently no data to suggest that methylprednisolone has significant analgesic benefit in adults having cardiac surgery.

Effect of methylprednisolone on acute kidney injury in patients undergoing cardiac surgery with a cardiopulmonary bypass pump: a randomized controlled trial

BACKGROUND

Perioperative corticosteroid use may reduce acute kidney injury. We sought to test whether methylprednisolone reduces the risk of acute kidney injury after cardiac surgery.

METHODS

We conducted a prespecified substudy of a randomized controlled trial involving patients undergoing cardiac surgery with cardiopulmonary bypass (2007-2014); patients were recruited from 79 centres in 18 countries. Eligibility criteria included a moderate-to-high risk of perioperative death based on a preoperative score of 6 or greater on the European System for Cardiac Operative Risk Evaluation I. Patients (n = 7286) were randomly assigned (1:1) to receive intravenous methylprednisolone (250 mg at anesthetic induction and 250 mg at initiation of cardiopulmonary bypass) or placebo. Patients, caregivers, data collectors and outcome adjudicators were unaware of the assigned intervention. The primary outcome was postoperative acute kidney injury, defined as an increase in the serum creatinine concentration (from the preoperative value) of 0.3 mg/dL or greater (≥ 26.5 μmol/L) or 50% or greater in the 14-day period after surgery, or use of dialysis within 30 days after surgery.

RESULTS

Acute kidney injury occurred in 1479/3647 patients (40.6%) in the methylprednisolone group and in 1426/3639 patients (39.2%) in the placebo group (adjusted relative risk 1.04, 95% confidence interval 0.96 to 1.11). Results were consistent across several definitions of acute kidney injury and in patients with preoperative chronic kidney disease.

INTERPRETATION

Intraoperative corticosteroid use did not reduce the risk of acute kidney injury in patients with a moderate-to-high risk of perioperative death who had cardiac surgery with cardiopulmonary bypass. Our results do not support the prophylactic use of steroids during cardiopulmonary bypass surgery. Trial registration: ClinicalTrials.gov, no. NCT00427388.

Steroids in cardiac surgery trial: a substudy of surgical site infections

PURPOSE

Postoperative infection, particularly in cardiac surgery, results in significant morbidity, mortality, and healthcare cost. Identification of novel predictors of postoperative infection can target high-risk populations for prophylactic intervention.

METHODS

Steroids in cardiac surgery (SIRS) was a multi-centre randomized-controlled trial assessing intraoperative administration of methylprednisone during cardiac surgery, which enrolled 7,507 patients across 80 centres in 18 countries. It demonstrated that administration of steroids had no effect on mortality or major morbidity after cardiac surgery. Our primary objective was to identify risk factors for postoperative surgical site infections using SIRS participants as a cohort. We excluded patients who did not undergo surgery, died intraoperatively, or died within 48 hr of the operation. Patients were assessed for development of "surgical site infection" over the first 30 days postoperatively. Using theoretical and previously identified risk factors, we used forward stepwise entry to create a binary logistic regression model.

RESULTS

Follow-up at 30 days was complete for all patients; 7,406 were included in the cohort. Surgical site infection occurred in 180 (4.8%) and 184 (5.0%) of patients in the placebo and steroid arms respectively. Significant risk factors (P < 0.05 level) included: diabetes managed with insulin (adjusted odds ratio [aOR]: 1.55; 95% confidence interval [CI] 1.13 to 2.12), oral hypoglycemics (aOR 1.60; 95% CI 1.18 to 2.16), or diet (aOR 1.81; 95% CI 1.16 to 2.83), female sex (aOR 1.34; 95% CI 1.05 to 1.71), renal failure with (aOR 2.03; 95% CI 1.06 to 3.91), and without (aOR 1.50; 95% CI 1.04 to 2.14) dialysis, > 96 min cardiopulmonary bypass (CPB) time (aOR 1.84; 95% CI 1.44 to 2.35), body mass index (BMI) < 22.3 (aOR 0.44; 95% CI 0.28 to 0.71) or > 30 (aOR 1.49; 95% CI 1.17 to 1.89), peak intensive care unit blood glucose (aOR 1.02 per mmol·L^-1; 95% CI 1.00 to 1.04), and coronary artery bypass grafting (CABG) operation type (aOR 2.59; 95% CI 1.87 to 3.59).

CONCLUSIONS

Patients undergoing CABG, requiring longer CPB, with higher BMI, or with diabetes, are at elevated risk of surgical site infection. Strategies to mitigate this risk warrant further investigation.

New-onset atrial fibrillation: an update

New-onset atrial fibrillation (NOAF) is the most common perioperative complication of heart surgery, typically occurring in the perioperative period. NOAF commonly occurs in patients who are elderly, or have left atrial enlargement, or left ventricular hypertrophy. Various factors have been identified as being involved in the development of NOAF, and numerous approaches have been proposed for its prevention and treatment. Risk factors include diabetes, obesity, and metabolic syndrome. For prevention of NOAF, β-blockers and amiodarone are particularly effective and are recommended by guidelines. NOAF can be treated by rhythm/rate control, and antithrombotic therapy. Treatment is required in patients with decreased cardiac function, a heart rate exceeding 130 beats/min, or persistent NOAF lasting for ≥ 48 h. It is anticipated that anticoagulant therapies, as well as hemodynamic management, will also play a major role in the management of NOAF. When using warfarin as an anticoagulant, its dose should be adjusted based on PT-INR. PT-INR should be controlled between 2.0 and 3.0 in patients aged < 70 years and between 1.6 and 2.6 in those aged ≥ 70 years. Rate control combined with antithrombotic therapies for NOAF is expected to contribute to further advances in treatment and improvement of survival.

Effects of HV-CRRT on PCT, TNF-α, IL-4, IL-6, IL-8 and IL-10 in patients with pancreatitis complicated by acute renal failure

The aim of the study was to investigate the effects of high-volume continuous renal replacement therapy (HV-CRRT) on procalcitonin (PCT), tumor necrosis factor-α (TNF-α), interleukin-4 (IL-4), IL-6, IL-8 and IL-10 in acute pancreatitis complicated by acute renal failure. Eighty-six patients with acute pancreatitis complicated with acute renal failure were selected from September 2014 to September 2016 in our hospital, and were treated by continuous veno-venous hemofiltration (CVVH). The patients were randomly divided into the observation group, treated by the HV-CVVH model with a displacement rate of 4 l/h, and the control group, treated by the normal capacity model with a displacement rate of 2 l/h. The levels of PCT, TNF-α, IL-4, IL-6, IL-8, and IL-10 in serum were measured by ELISA before and 2, 6 and 12 h after treatment, and 12 h after CVVH. The serum PCT and TNF-α levels in the two groups were decreased at 2 h after treatment. The lowest levels appeared at 6 h after treatment, and then recovered, but remained lower than those before treatment (p<0.05). The levels of IL-4, IL-6, IL-8 and IL-10, as well as PCT and TNF-α in the two groups were significantly lower than those before treatment, and the decreases in the observation group were more obvious than those in the control group (p<0.05). In conclusion, compared with the standard volume method, HV-CRRT can more effectively remove various inflammatory factors and reduce the levels of serum PCT for the treatment of pancreatitis complicated by acute renal failure. Additionally, replacement of the blood filter at appropriate time-points can improve the treatment efficacy.

Gene Expression Profiles for the Identification of Prevalent Atrial Fibrillation

BACKGROUND

Diagnosis of atrial fibrillation (AF) can be difficult, requiring cumbersome investigations. We aimed to determine the association of established whole-blood gene expression scores with prevalent AF and to evaluate their performance for the identification of AF in a SIRS (Steroids in Cardiac Surgery) trial cohort.

METHODS AND RESULTS

Whole-blood, transcriptome-wide gene expression profiling was performed using the Illumina HumanHT-12 Expression BeadChip in 416 participants (65% men) before surgery, including 91 with a diagnosis of AF. An AF gene score (GS) calculated from 7 genes reported to be upregulated in AF and a validated GS for biological age based on 1254 genes related to aging were both independently associated with AF diagnosis before surgery in multivariate logistic regression analyses adjusting for known risk factors (P=0.0006 and P=0.003). Addition of AF and biological age GSs to clinical risk factors led to significant improvement in area under the receiver operating characteristic curve (from 0.77 to 0.80; P=0.03), continuous net reclassification improvement index (P<0.0001), and integrated discrimination improvement index (P=0.0002). When stratifying AF by subtype, AF GS was mainly associated with paroxysmal AF (P=0.003), whereas the biological age GS was mainly associated with permanent AF (P=0.017).

CONCLUSIONS

We validated the existence of a blood gene expression signature for prevalent AF and showed that biological age derived from gene expression is significantly associated with prevalent AF. These findings suggest a potential utility of blood gene expression for the identification of patients with AF, particularly paroxysmal AF. This result could have implications for the prevention and management of cryptogenic stroke.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00427388.

Postoperative atrial fibrillation: The role of the inflammatory response

OBJECTIVE

Abnormal atrial conduction has been shown to be a substrate for postoperative atrial fibrillation (POAF). This study aimed to determine the relationship between the location of the atrial reentry responsible for POAF, and degree of atrial inflammation.

METHODS

Normal mongrel dogs (n = 18) were divided into 3 groups: anesthesia alone (anesthesia), lateral right atriotomy (atriotomy), and lateral right atriotomy with anti-inflammatory therapy (steroid). Conduction properties of the right and left atria (RA and LA) were examined 3 days postoperatively by mapping. Activation was observed during burst pacing-induced AF. The RA and LA myeloperoxidase activity was measured to quantitate the degree of inflammation.

RESULTS

Sustained AF (>2 minutes) was induced in 5 of 6 animals in the atriotomy group, but in none in the anesthesia or steroid groups. All sustained AF originated from around the RA incision. Three of these animals had an incisional reentrant tachycardia around the right atriotomy and 2 had a focal activation arising from the RA during AF. The LA activations in these animals were passive from the RA activation. The RA activation of the atriotomy group was more inhomogeneous than that of the anesthesia group (inhomogeneity index: 2.0 ± 0.2 vs 1.0 ± 0.1, P < .01). Steroid therapy significantly normalized the RA activation after the atriotomy (1.2 ± 0.1, P < .01). The inhomogeneity of the atrial conduction correlated with the myeloperoxidase activity (r = 0.774, P < .001).

CONCLUSIONS

Reentrant circuits responsible for POAF are dependent on the degree of inflammation and rotate around the atriotomy. Anti-inflammatory therapy decreased the risk of postoperative AF.

Anesthetic Management for Resection of Bilateral Pulmonary Artery Sarcoma

We describe a patient who presented with a bilateral pulmonary artery sarcoma, initially treated as pulmonary embolism, that necessitated concomitant pulmonary endarterectomy and pneumonectomy. We reviewed the anesthetic management used for this procedure, which bears many similarities to the management of patients undergoing pulmonary thromboendarterectomy. Right ventricular failure, pulmonary hemorrhage, and cerebral ischemia due to circulatory arrest are life-threatening perioperative complications. The anesthesiologist can play a key role in the prevention (or timely recognition and treatment) of these perioperative complications by establishing adequate hemodynamic, echocardiographic, and neurologic monitoring and by optimizing cardiopulmonary function and coagulation.

Effects of remote ischemic preconditioning in high-risk patients undergoing cardiac surgery (Remote IMPACT): a randomized controlled trial

BACKGROUND

Remote ischemic preconditioning is a simple therapy that may reduce cardiac and kidney injury. We undertook a randomized controlled trial to evaluate the effect of this therapy on markers of heart and kidney injury after cardiac surgery.

METHODS

Patients at high risk of death within 30 days after cardiac surgery were randomly assigned to undergo remote ischemic preconditioning or a sham procedure after induction of anesthesia. The preconditioning therapy was three 5-minute cycles of thigh ischemia, with 5 minutes of reperfusion between cycles. The sham procedure was identical except that ischemia was not induced. The primary outcome was peak creatine kinase-myocardial band (CK-MB) within 24 hours after surgery (expressed as multiples of the upper limit of normal, with log transformation). The secondary outcome was change in creatinine level within 4 days after surgery (expressed as log-transformed micromoles per litre). Patient-important outcomes were assessed up to 6 months after randomization.

RESULTS

We randomly assigned 128 patients to remote ischemic preconditioning and 130 to the sham therapy. There were no significant differences in postoperative CK-MB (absolute mean difference 0.15, 95% confidence interval [CI] -0.07 to 0.36) or creatinine (absolute mean difference 0.06, 95% CI -0.10 to 0.23). Other outcomes did not differ significantly for remote ischemic preconditioning relative to the sham therapy: for myocardial infarction, relative risk (RR) 1.35 (95% CI 0.85 to 2.17); for acute kidney injury, RR 1.10 (95% CI 0.68 to 1.78); for stroke, RR 1.02 (95% CI 0.34 to 3.07); and for death, RR 1.47 (95% CI 0.65 to 3.31).

INTERPRETATION

Remote ischemic precnditioning did not reduce myocardial or kidney injury during cardiac surgery. This type of therapy is unlikely to substantially improve patient-important outcomes in cardiac surgery.

TRIAL REGISTRATION

ClinicalTrials.gov, no. NCT01071265.

Methylprednisolone Does Not Reduce Persistent Pain after Cardiac Surgery

Background

Persistent incisional pain is common after cardiac surgery and is believed to be in part related to inflammation and poorly controlled acute pain. Methylprednisolone is a corticosteroid with substantial antiinflammatory and analgesic properties and is thus likely to ameliorate persistent surgical pain. Therefore, the authors tested the primary hypothesis that patients randomized to methylprednisolone have less persistent incisional pain than those given placebo.

Methods

One thousand forty-three patients having cardiopulmonary bypass for cardiac surgery via a median sternotomy were included in this substudy of Steroids in Cardiac Surgery (SIRS) trial. Patients were randomized to 500 mg intraoperative methylprednisolone or placebo. Incisional pain was assessed at 30 days and 6 months after surgery, and the potential risk factors were also evaluated.

Results

Methylprednisolone administration did not reduce pain at 30 days or persistent incisional pain at 6 months, which occurred in 78 of 520 patients (15.7%) in the methylprednisolone group and in 88 of 523 patients (17.8%) in the placebo group. The odds ratio for methylprednisolone was 0.93 (95% CI, 0.79 to 1.09, P = 0.37). Furthermore, there was no difference in worst pain and average pain in the last 24 h, pain interference with daily life, or use of pain medicine at 6 months. Younger age, female sex, and surgical infections were associated with the development of persistent incisional pain.

Conclusions

Intraoperative methylprednisolone administration does not reduce persistent incisional pain at 6 months in patients recovering from cardiac surgery.

Methylprednisolone in patients undergoing cardiopulmonary bypass (SIRS): a randomised, double-blind, placebo-controlled trial

BACKGROUND

Cardiopulmonary bypass initiates a systemic inflammatory response syndrome that is associated with postoperative morbidity and mortality. Steroids suppress inflammatory responses and might improve outcomes in patients at high risk of morbidity and mortality undergoing cardiopulmonary bypass. We aimed to assess the effects of steroids in patients at high risk of morbidity and mortality undergoing cardiopulmonary bypass.

METHODS

The Steroids In caRdiac Surgery (SIRS) study is a double-blind, randomised, controlled trial. We used a central computerised phone or interactive web system to randomly assign (1:1) patients at high risk of morbidity and mortality from 80 hospital or cardiac surgery centres in 18 countries undergoing cardiac surgery with the use of cardiopulmonary bypass to receive either methylprednisolone (250 mg at anaesthetic induction and 250 mg at initiation of cardiopulmonary bypass) or placebo. Patients were assigned with block randomisation with random block sizes of 2, 4, or 6 and stratified by centre. Patients aged 18 years or older were eligible if they had a European System for Cardiac Operative Risk Evaluation of at least 6. Patients were excluded if they were taking or expected to receive systemic steroids in the immediate postoperative period or had a history of bacterial or fungal infection in the preceding 30 days. Patients, caregivers, and those assessing outcomes were masked to allocation. The primary outcomes were 30-day mortality and a composite of death and major morbidity (ie, myocardial injury, stroke, renal failure, or respiratory failure) within 30 days, both analysed by intention to treat. Safety outcomes were also analysed by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00427388.

FINDINGS

Patients were recruited between June 21, 2007, and Dec 19, 2013. Complete 30-day data was available for all 7507 patients randomly assigned to methylprednisolone (n=3755) and to placebo (n=3752). Methylprednisolone, compared with placebo, did not reduce the risk of death at 30 days (154 [4%] vs 177 [5%] patients; relative risk [RR] 0·87, 95% CI 0·70-1·07, p=0·19) or the risk of death or major morbidity (909 [24%] vs 885 [24%]; RR 1·03, 95% CI 0·95-1·11, p=0·52). The most common safety outcomes in the methylprednisolone and placebo group were infection (465 [12%] vs 493 [13%]), surgical site infection (151 [4%] vs 151 [4%]), and delirium (295 [8%] vs 289 [8%]).

INTERPRETATION

Methylprednisolone did not have a significant effect on mortality or major morbidity after cardiac surgery with cardiopulmonary bypass. The SIRS trial does not support the routine use of methylprednisolone for patients undergoing cardiopulmonary bypass.

FUNDING

Canadian Institutes of Health Research.

Pulmonary complications of cardiopulmonary bypass

Pulmonary complications after the use of extracorporeal circulation are common, and they range from transient hypoxemia with altered gas exchange to acute respiratory distress syndrome (ARDS), with variable severity. Similar to other end-organ dysfunction after cardiac surgery with extracorporeal circulation, pulmonary complications are attributed to the inflammatory response, ischemia-reperfusion injury, and reactive oxygen species liberated as a result of cardiopulmonary bypass. Several factors common in cardiac surgery with extracorporeal circulation may worsen the risk of pulmonary complications including atelectasis, transfusion requirement, older age, heart failure, emergency surgery, and prolonged duration of bypass. There is no magic bullet to prevent or treat pulmonary complications, but supportive care with protective ventilation is important. Targets for the prevention of pulmonary complications include mechanical, surgical, and anesthetic interventions that aim to reduce the contact activation, systemic inflammatory response, leukocyte sequestration, and hemodilution associated with extracorporeal circulation.

Systemic inflammatory response syndrome after transcatheter or surgical aortic valve replacement

OBJECTIVE

An inflammatory response after cardiac surgery is associated with worse clinical outcomes, but recent trials to attenuate it have been neutral. We evaluated the association between systemic inflammatory response syndrome (SIRS) and mortality after transcatheter (TAVR) and surgical aortic valve replacement (SAVR) for aortic stenosis (AS) and evaluated whether diabetes influenced this relationship.

METHODS

Patients (n=747) with severe AS treated with TAVR (n=264) or SAVR (n=483) between January 2008 and December 2013 were included and 37% had diabetes mellitus. SIRS was defined by four criteria 12-48 h after aortic valve replacement (AVR): (1) white blood cell count <4 or >12; (2) heart rate >90; (3) temperature <36 or >38°C; or (4) respiratory rate >20. Severe SIRS was defined as meeting all four criteria. The primary endpoint was 6-month all-cause mortality (60 deaths occurred by 6 months). Inverse probability weighting (IPW) was performed on 44 baseline and procedural variables to minimise confounding.

RESULTS

Severe SIRS developed in 6% of TAVR patients and 11% of SAVR patients (p=0.02). Six-month mortality tended to be higher in those with severe SIRS (15.5%) versus those without (7.4%) (p=0.07). After adjustment, severe SIRS was associated with higher 6-month mortality (IPW adjusted HR 2.77, 95% CI 2.04 to 3.76, p<0.001). Moreover, severe SIRS was more strongly associated with increased mortality in diabetic (IPW adjusted HR 4.12, 95% CI 2.69 to 6.31, p<0.001) than non-diabetic patients (IPW adjusted HR 1.74, 95% CI 1.10 to 2.73, p=0.02) (interaction p=0.007). The adverse effect of severe SIRS on mortality was similar after TAVR and SAVR.

CONCLUSIONS

Severe SIRS was associated with a higher mortality after SAVR or TAVR. It occurred more commonly after SAVR and had a greater effect on mortality in diabetic patients. These findings may have implications for treatment decisions in patients with AS, may help explain differences in outcomes between different AVR approaches and identify diabetic patients as a high-risk subgroup to target in clinical trials with therapies to attenuate SIRS.

AKI associated with cardiac surgery

Approximately 18% of patients undergoing cardiac surgery experience AKI (on the basis of modern standardized definitions of AKI), and approximately 2%-6% will require hemodialysis. The development of AKI after cardiac surgery portends poor short- and long-term prognoses, with those developing RIFLE failure or AKI Network stage III having an almost 2-fold increase in the risk of death. AKI is caused by a variety of factors, including nephrotoxins, hypoxia, mechanical trauma, inflammation, cardiopulmonary bypass, and hemodynamic instability, and it may be affected by the clinician's choice of fluids and vasoactive agents as well as the transfusion strategy used. The risk of AKI may be ameliorated by avoidance of nephrotoxins, achievement of adequate glucose control preoperatively, and use of goal-directed therapy hemodynamic strategies. Remote ischemic preconditioning is an exciting future strategy, but more work is needed before widespread implementation. Unfortunately, there are no pharmacologic agents known to reduce the risk of AKI or treat established AKI.