Renal dysfunction after thoracic aortic surgery requiring deep hypothermic circulatory arrest: definition, incidence, and clinical predictors

Risk factors for the in-hospital mortality of CRRT-therapy patients with cardiac surgery-associated AKI: a single-center clinical study in China

OBJECTIVE

We retrospectively analyzed risk factors on in-hospital mortality in CRRT-therapy patients with open cardiac surgery (CS)-induced acute kidney injury (AKI), to provide the clinical basis for predicting and lowering the in-hospital mortality after CS.

METHODS

84 CS-AKI patients with CRRT were divided into survival and death groups according to discharge status, and the perioperative data were analyzed with R version 4.0.2.

RESULTS

There were significant differences between the two groups, including: urea nitrogen, Sequential Organ Failure Assessment (SOFA) score and vasoactive-inotropic score (VIS) on the first day after operation; VIS just before CRRT; SOFA score and negative balance of blood volume 24 h after CRRT; the incidence rate of bleeding, severe infection and MODS after operation; and the interval between AKI and CRRT. Univariate logistic regression analysis showed that SOFA score and VIS on the first day after operation; VIS just before CRRT; VIS and negative balance of blood volume 24 h after CRRT; the incidence rate of bleeding, infection and multiple organ dysfunction syndrome (MODS) after operation; bootstrap resampling analysis showed that SOFA score and VIS 24 h after CRRT, as well as the incidence of bleeding after operation were the independent risk factors.

CONCLUSION

Maintaining stable hemodynamics and active prevention of bleeding are expected to decrease the in-hospital mortality.

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.

Does deeper hypothermia reduce the risk of acute kidney injury after circulatory arrest for aortic arch surgery?

OBJECTIVES

The impact of hypothermic circulatory arrest (HCA) temperature on postoperative acute kidney injury (AKI) has not been evaluated. This study examined the association between circulatory arrest temperatures and AKI in patients undergoing proximal aortic surgery with HCA.

METHODS

A total of 759 consecutive patients who underwent proximal aortic surgery (ascending ± valve ± root) including arch replacement requiring HCA between July 2005 and December 2016 were identified from a prospectively maintained institutional aortic surgery database. The primary outcome was AKI as defined by Risk, Injury, Failure, Loss, End Stage Renal Disease (ESRD) criteria. The association between minimum nasopharyngeal (NP) and bladder temperatures during HCA and postoperative AKI was assessed, adjusting for patient-level factors using multivariable logistic regression.

RESULTS

A total of 85% (n = 645) of patients underwent deep hypothermia (14.1-20.0°C), 11% (n = 83) low-moderate hypothermia (20.1-24.0°C) and 4% (n = 31) high-moderate hypothermia (24.1-28.0°C) as classified by NP temperature. When analysed by bladder temperature, 59% (n = 447) underwent deep hypothermia, 22% (n = 170) low-moderate, 16% (n = 118) high-moderate and 3% mild (n = 24) (28.1-34.0°C) hypothermia. The median systemic circulatory arrest time was 17 min. The incidence of AKI did not differ between hypothermia groups, whether analysed using minimum NP or bladder temperature. In the multivariable analysis, the association between degree of hypothermia and AKI remained non-significant whether analysed as a categorical variable (hypothermia group) or as a continuous variable (minimum NP or bladder temperature) (all P > 0.05).

CONCLUSIONS

In patients undergoing proximal aortic surgery including arch replacement requiring HCA, degree of systemic hypothermia was not associated with the risk of AKI. These data suggest that moderate hypothermia does not confer increased risk of AKI for patients requiring circulatory arrest, although additional prospective data are needed.

Acute kidney injury in patients operated on for type A acute aortic dissection: incidence, risk factors and short-term outcomes

OBJECTIVES

Acute kidney injury (AKI) is a relatively common complication after an operation for type A acute aortic dissection and is indicative of a poor prognosis. We examined the risk factors for and the outcomes of developing AKI in patients being operated on for thoracic aortic diseases.

METHODS

We retrospectively analysed 712 patients with acute type A dissection who had deep hypothermic circulatory operations from January 2014 to December 2018, emphasizing those who developed AKI. Logistic regression models were used to identify predisposing factors for the postoperative development of AKI.

RESULTS

Among all enrolled patients, 359 (50.4%) had AKI; of these, 133 were diagnosed as stage 1 (18.7%), 126 were stage 2 (17.7%) and 100 were stage 3 (14.0%). Postoperative haemodialysis was required in 111 patients (15.9%). The development of AKI after aortic surgery contributed to the higher mortality rate within 30 days after surgery (P < 0.001), longer stay in the intensive care unit (P = 0.01) and longer hospital stay (P < 0.001). Binary logistic regression analysis showed that preoperative cystatin C levels [odds ratio (OR) 2.615, 95% confidence interval (CI) 1.139-6.002; P = 0.023] and postoperative ventilation time (OR 1.019, 95% CI 1.005-1.034; P = 0.009) were independent risk factors for developing AKI. Multiple ordinal logistic regression analyses showed that the preoperative cystatin C level (OR 2.921, 95% CI 1.542-5.540; P = 0.001) was an independent risk factor associated with the severity of AKI.

CONCLUSIONS

Our data suggested that the development of AKI after surgery for type A acute aortic dissection was common and associated with an increased short-term mortality rate. The preoperative cystatin C level was identified as an indicator for the occurrence and severity of AKI postoperatively. Furthermore, we discovered that longer postoperative ventilation time was also associated with the development of AKI.

Blood cytokine expression correlates with early multi-organ damage in a mouse model of moderate hypothermia with circulatory arrest using cardiopulmonary bypass

Cardiopulmonary bypass (CPB) with moderate hypothermic cardiac arrest (MHCA) is essential for prolonged complex procedures in cardiac surgery and is associated with postoperative complications. Although cytokine release provoked through MHCA under CPB plays a pivotal role in postoperative organ damage, the pathomechanisms are unclear. Here, we investigated the cytokine release pattern and histological organ damage after MHCA using a recently described mouse CPB model. Eight BALB/c mice underwent 60 minutes of circulatory arrest under CPB, were successively rewarmed and reperfused. Blood cytokine concentrations and liver and kidney function parameters were measured and histological changes to these organs were compared to control animals. Our results showed a marked increase in proinflammatory cytokines and histological changes in the kidney, lung, and liver after CPB. Furthermore, clinical chemistry showed signs of hemolysis and acute kidney injury. These results suggest early onset of solid organ injury which correlates with increased leukocyte infiltration. A better understanding of the interplay between pro-inflammatory cytokine activation and solid organ injury in this model of CBP with MHCA will inform strategies to reduce organ damage during cardiac surgeries in the clinic.

Whole body perfusion strategy for aortic arch repair under moderate hypothermia

INTRODUCTION

Aortic arch reconstruction under moderate hypothermia is commonly performed with antegrade cerebral perfusion (ACP) for brain protection; however, hypothermia alone is often solely relied upon for visceral and lower body protection. We investigated whether the addition of simultaneous lower body perfusion to ACP (whole body perfusion - WBP) may ameliorate the metabolic derangements of moderate hypothermic circulatory arrest (MHCA).

METHODS

Between 2008 and 2014, 106 consecutive patients underwent elective or emergent aortic arch surgery with MHCA, with either ACP only (44 patients, 66±12 years, 30% female) or WBP (62 patients, 61±15 years, 31% female). Primary outcomes included 30-day/in-hospital mortality, intensive care unit (ICU) and hospital lengths of stay (LOS) and specific parameters of metabolic recovery.

RESULTS

There were no significant differences between the groups in 30-day/in-hospital mortality (ACP: 3 (6.8%), WBP: 2 (3.2%); p=0.65), stroke (ACP: 1 (2.3%), WBP: 1 (1.6%); p=1.0) or renal failure (ACP: 2 (4.5%), WBP: 1 (1.5%); p=0.57). In the WBP group, we identified a significant reduction in lactate level at ICU admission (ACP 5.5 vs. WBP 3.5 mmol/L; p=0.002), time to lactate normalization (p=0.014) and median ICU length-of-stay (ACP 3 vs. WBP 1 days; p=0.049). There was no difference in post-operative creatinine (ACP: 104, WBP: 107 μmol/L; p=0.66). After multivariable regression adjustment, perfusion strategy no longer remained an independent predictor of ICU discharge time (p=0.09), however, cardiopulmonary bypass time (p=0.02), age (p=0.012) and emergent surgery (p=0.02) were.

CONCLUSIONS

A WBP strategy during aortic arch reconstruction with MHCA may be associated with more rapid normalization of metabolic parameters and reduced ICU length of stay compared to using ACP alone. Further evaluation with a randomized trial is warranted.

Immediate ICU Care for Patients Following Aortic Arch Surgery

Patients undergoing aortic arch surgery are at high risk for stroke, delirium, low cardiac output, respiratory failure, renal failure, and coagulopathy. A significantly higher mortality is seen in patients experiencing any of these complications when compared with those without complications. As surgical, perfusion, and anesthetic techniques improve, the incidence of major complications have decreased. A recent paradigm shift in cardiac surgery has focused on rapid postoperative recovery, and a similar change has affected the care of patients after arch surgery. Nevertheless, a small subset of patients experience significant morbidity and mortality after aortic arch surgery, and rapid identification of any organ dysfunction and appropriate supportive care is critical in these patients. In this article, the current state of postoperative care of the patient after open aortic arch surgery will be reviewed.

Prediction and Prevention of Acute Kidney Injury after Cardiac Surgery

The incidence of acute kidney injury after cardiac surgery (CS-AKI) ranges from 33% to 94% and is associated with a high incidence of morbidity and mortality. The etiology is suggested to be multifactorial and related to almost all aspects of perioperative management. Numerous studies have reported the risk factors and risk scores and novel biomarkers of AKI have been investigated to facilitate the subclinical diagnosis of AKI. Based on the known independent risk factors, many preventive interventions to reduce the risk of CS-AKI have been tested. However, any single preventive intervention did not show a definite and persistent benefit to reduce the incidence of CS-AKI. Goal-directed therapy has been considered to be a preventive strategy with a substantial level of efficacy. Many pharmacologic agents were tested for any benefit to treat or prevent CS-AKI but the results were conflicting and evidences are still lacking. The present review will summarize the current updated evidences about the risk factors and preventive strategies for CS-AKI.

Risk factors for acute kidney injury in overweight patients with acute type A aortic dissection: a retrospective study

BACKGROUND

To identify risk factors for acute kidney injury (AKI) in overweight patients who underwent surgery for acute type A aortic dissection (TAAD).

METHODS

A retrospective study including 108 consecutive overweight patients [body mass index (BMI) ≥24] between December 2009 and April 2013 in Beijing Anzhen Hospital has been performed. AKI was defined by Acute Kidney Injury Network (AKIN) criteria, which is based on serum creatinine (sCr) or urine output.

RESULTS

The mean age of the patients was 43.69±9.66 years. Seventy-two patients (66.7%) developed AKI during the postoperative period. A logistic regression analysis was performed to identify two independent risk factors for AKI: elevated preoperative sCr level and 72-h drainage volume. Renal replacement therapy (RRT) was required in 15 patients (13.9%). The overall postoperative mortality rate was 7.4%, 8.3% in AKI group and 5.6% in non-AKI group. There is no statistically significant difference between the two groups (P=0.32).

CONCLUSIONS

A higher incidence of AKI (66.7%) in overweight patients with acute TAAD was confirmed. The logistic regression model identified elevated preoperative sCr level and 72-h drainage volume as independent risk factors for AKI in overweight patients. We should pay more attention to prevent AKI in overweight patients with TAAD.

Reduction in the incidence of acute kidney injury after aortic arch surgery with low-dose atrial natriuretic peptide: a randomised controlled trial

BACKGROUND

Acute kidney injury (AKI) after surgery is associated with an increased risk of adverse events and death. Atrial natriuretic peptide (ANP) dilates the preglomerular renal arteries and inhibits the renin-angiotensin axis. A low-dose ANP infusion increases glomerular filtration rate after cardiovascular surgery, but it is not known whether it reduces the incidence of AKI or the mortality rate.

OBJECTIVE

To evaluate whether an intravenous ANP infusion prevents AKI in patients undergoing aortic arch surgery requiring hypothermic circulatory arrest.

DESIGN

A randomised controlled study.

SETTING

Operating room and intensive care unit at Kawasaki Saiwai Hospital, Kanagawa, Japan.

PATIENTS

Forty-two patients with normal preoperative renal function undergoing elective repair of an aortic arch aneurysm.

INTERVENTION

Patients were assigned randomly to receive a fixed dose of ANP (0.0125 μg (-1) kg(-1)  min) or placebo. The infusion was started after induction of anaesthesia and continued for 24  h postoperatively.

MAIN OUTCOME MEASURES

The primary end-point was the incidence of AKI within 48 h after surgery.

RESULTS

AKI developed in 30% of patients who received ANP compared with 73% of patients who received placebo (P = 0.014). Intraoperative urine output was almost 1 l greater in patients who received ANP (1865 ± 1299 versus 991 ± 480  ml in the control group, P = 0.005). However, there were no differences in mean arterial pressure or number of episodes of hypotension between the groups. Length of hospital and intensive care stays were not significantly different, nor was there a difference in 30-day mortality. No patients required haemodialysis or continuous renal replacement therapy.

CONCLUSION

We found that an intravenous infusion of ANP at 0.0125  μg  kg(-1)  min(-1) is an effective intervention for reducing the incidence of postoperative AKI, and appears to afford a degree of renal protection during and after cardiovascular surgery.

TRIAL REGISTRATION

Kawasaki ANP trial, UMIN Clinical Trials Registry ID: UMIN000011650.

Potentially modifiable risk factors for acute kidney injury after surgery on the thoracic aorta: a propensity score matched case-control study

Perioperative risk factors were identified for acute kidney injury (AKI) defined by the RIFLE criteria (RIFLE = risk, injury, failure, loss, end stage) after surgery on the thoracic aorta with cardiopulmonary bypass (CPB) in this case-control study. A retrospective review was completed for 702 patients who underwent surgery on the thoracic aorta with CPB. A total of 183 patients with AKI were matched 1:1 with patients without AKI by a propensity score. Matched variables included age, gender, body-mass index, preoperative creatinine levels, estimated glomerular filtration rate, a history of hypertension, diabetes mellitus, cerebrovascular accident, smoking history, or chronic obstructive pulmonary disease to exclude the influence of patient demographics, preoperative medical status, and baseline renal function. Multivariate logistic regression analysis was used to evaluate for independent risk factors in the matched sample of 366 patients. The incidence of AKI was 28.6% and 5.9% of patients from the entire sample required renal replacement therapy. AKI was associated with a prolonged postoperative hospital stay and a higher one-month and one-year mortality both in the entire and matched sample set. Independent risk factors for AKI were a left ventricular ejection fraction <55%, preoperative hemoglobin level <10 g/dL, albumin <4.0 g/dL, diagnosis of dissection, operation time >7 hours, deep hypothermic circulatory arrest (DHCA) time >30 min, pRBC transfusion >1000 mL, and FFP transfusion >500 mL. Although the incidence of poor glucose control (blood glucose >180 mg/dL) was higher in patients with AKI in matched sample, it was not an independent risk factor.AKI was still associated with a poor clinical outcome in the matched sample. Potentially modifiable risk factors included preoperative anemia and hypoalbuminemia. Efforts to minimize operation time and DHCA time along with transfusion amount may protect patients undergoing aortic surgery against AKI.

Low levels of urinary liver-type fatty acid-binding protein may indicate a lack of kidney protection during aortic arch surgery requiring hypothermic circulatory arrest

STUDY OBJECTIVE

To examine the change in liver-type fatty acid-binding protein (L-FABP) levels in patients undergoing aortic arch surgery and the correlation between L-FABP and postoperative acute kidney injury.

DESIGN

Prospective observational study.

SETTING

Operating room of a general hospital.

PATIENTS

36 adult patients.

INTERVENTIONS AND MEASUREMENTS

Urine samples were obtained to measure urinary L-FABP at initiation of cardiopulmonary bypass (CPB) and 5 minutes after termination of hypothermic circulatory arrest.

MAIN RESULTS

22 (61.1%) patients developed acute kidney injury within a 48-hour period. L-FABP increases more than a thousand-fold were found. In patients who subsequently developed acute kidney injury, significant increases in L-FABP were noted from 2.9 (3.6) ng/mg of creatinine before CPB to 62.1 (995.6) ng/mg of creatinine 5 minutes after termination of circulatory arrest. Values in patients who did not develop acute kidney injury increased from 1.1 (5.7) ng/mg before CPB to 1133.0 (6358.8) ng/mg of creatinine showing a significant mean difference (P = 0.011). The area under the L-FABP receiver operating characteristic curve at 5 minutes after termination of circulatory arrest was 0.758. A cutoff value of 75.13 ng/mg of creatinine yielded both good sensitivity (1.000) and specificity (0.546) for detecting non-acute kidney injury. Patients who developed acute kidney injury after aortic arch surgery demonstrated lower levels of urinary L-FABP.

CONCLUSIONS

Low levels of urinary L-FABP may indicate kidney injury and lack of renal protection.

Simplified clinical risk score to predict acute kidney injury after aortic surgery

OBJECTIVE

The authors identified risk factors for acute kidney injury (AKI) defined by risk, injury, failure, loss, end-stage (RIFLE) criteria after aortic surgery with cardiopulmonary bypass and constructed a simplified risk score for the prediction of AKI.

DESIGN

Retrospective and observational.

SETTING

Single large university hospital.

PARTICIPANTS

Patients (737) who underwent aortic surgery with cardiopulmonary bypass between 1997 and 2010.

MAIN RESULTS

Multivariate logistic regression analysis was used to evaluate risk factors. A scoring model was developed in a randomly selected derivation cohort (n = 417), and was validated on the remaining patients. The scoring model was developed with a score based on regression β-coefficient, and was compared with previous indices as measured by the area under the receiver operating characteristic curve (AUC). The incidence of AKI was 29.0%, and 5.8% required renal replacement therapy. Independent risk factors for AKI were age older than 60 years, preoperative glomerular filtration rate <60 mL/min/1.73 m(2), left ventricular ejection fraction <55%, operation time >7 hours, intraoperative urine output <0.5 mL/kg/h, and intraoperative furosemide use. The authors made a score by weighting them at 1 point each. The risk score was valid in predicting AKI, and the AUC was 0.74 [95% confidence interval (CI): 0.69 to 0.79], which was similar to that in the validation cohort: 0.74 (95% CI: 0.69 to 0.80; p = 0.97). The risk-scoring model showed a better performance compared with previously reported indices.

CONCLUSIONS

The model would provide a simplified clinical score stratifying the risk of postoperative AKI in patients undergoing aortic surgery.

Aortic arch surgery using moderate hypothermia and unilateral selective antegrade cerebral perfusion

BACKGROUND

Cerebral protection and circulatory management remains a controversial issue in aortic arch surgery. The present study reported surgical outcomes of arch repair using moderate hypothermic circulatory arrest (MHCA) and unilateral selective antegrade perfusion (uSACP).

METHODS

From January 2004 and December 2012, 500 patients underwent hemiarch repair (HARCH) and 124 underwent total arch replacement (TARCH) utilizing moderate hypothermic circulatory arrest with unilateral selective antegrade cerebral perfusion of the right axillary artery. Emergent surgery was required in 142 (28.4%) of HARCH patients and 18 (14.5%) of TARCH patients. Mean arrest temperature ranged from 25.6-27.2 °C for elective and emergent operations in both groups. Mean circulatory arrest was 26.8 minutes for hemiarch repairs and 54.2 minutes for total arch replacement.

RESULTS

Overall mortality was 6.6% for hemiarch repairs and 9.7% for total arch replacements. Hospital mortality was 4.5% (16/358) and 10.4% (11/106) in elective cases, and 12% (17/142) and 5.6% (1/18) in elective cases, for hemiarch and total arch replacements respectively. Permanent neurological deficit (PND) occurred in 3 total arch replacement cases (2.4%). Multivariate analysis demonstrated that temperature was not found to be an independent risk factor during hemiarch or total arch replacements for mortality, permanent or neurological deficits, or renal failure.

CONCLUSIONS

Our approach for hemiarch and total arch repair utilizing MHCA and uSACP via the right axillary artery was associated excellent neurological and survival outcomes. Moderate hypothermia did not adversely impact cerebral or visceral organ protection.

The effect of the time interval between coronary angiography and on-pump cardiac surgery on risk of postoperative acute kidney injury: a meta-analysis

Background

Reports of the association between the time interval from coronary angiography (CAG) to cardiac surgery and risk of postoperative acute kidney injury (AKI) are controversial. We attempted to examine this association by conducting a meta-analysis.

Methods

We searched the Pubmed, MEDLINE, EMBASE, Web of Science databases, and the Cochrane Library from January 1966 to March 2013. A meta-analysis of studies reporting data for 1-day and 3-day time intervals between CAG and cardiac surgery was conducted after evaluation of heterogeneity and publication bias. Study-specific estimates were combined with inverse variance-weighted averages of logarithmic odds ratios (ORs) in fixed-effects models.

Results

From 8 studies involving 11542 persons, the pooled OR of AKI associated with an interval of 1 day or less between CAG and surgery was 1.21 (95% confidence interval (CI), 1.04 to 1.39) relative to an interval of more than 1 day. From 4 studies involving 5420 persons in the cardiopulmonary-bypass subgroup, the pooled OR of AKI associated with an interval of 3 days or less between CAG and surgery was 1.25 (95% CI, 1.07 to 1.43) relative to an interval of more than 3 days. The adjusted OR of the study in the cardiopulmonary bypass/ deep hypothermic circulatory arrest subgroup was 0.35 (95% CI, 0.17 to 0.73).

Conclusions

A time interval of 1 day or less between CAG and on-pump cardiac surgery was significantly associated with increased risk of AKI. A delay of on-pump cardiac surgery until 24 hours after CAG can potentially decrease postoperative AKI.

Outcome of elective total aortic arch replacement in patients with non-dialysis-dependent renal insufficiency stratified by estimated glomerular filtration rate

OBJECTIVE

Little is known about the impact of preoperative renal function stratified by estimated glomerular filtration rate (eGFR) on outcomes of total aortic arch replacement (TAR). The current study addressed this issue and identified a cutoff value of eGFR for the requirement of postoperative renal replacement therapy.

METHODS

From January 2000 to May 2011, 229 consecutive patients who did not require preoperative hemodialysis were retrospectively studied after elective TAR. Patients were grouped into the following categories: those with normal renal function (eGFR >90 mL/min/1.73 m(2); n = 11) and those with mild (eGFR, 60-90 mL/min/1.73 m(2); n = 86), moderate (eGFR, 30-59 mL/min/1.73 m(2); n = 111), or severe (eGFR <30 mL/min/1.73 m(2); n = 21) renal dysfunction. Linear trend tests demonstrated that the lower categories of eGFR were associated with a higher age, hypertension, coronary artery disease, peripheral arterial disease, and a higher EuroSCORE II.

RESULTS

The overall hospital mortality was 2.2%. A lower categories of eGFR were an independent risk factor for hospital mortality (odds ratio, 0.91; P = .002) and postoperative renal replacement therapy (odds ratio, 0.94; P < .002). A cutoff value for the requirement of postoperative renal replacement therapy was 26.0 mL/min/1.73 m(2). Patients in the lower categories of eGFR had significantly higher hospital mortality (P = .03) and more morbidities, such as renal replacement therapy (P < .01), postoperative permanent neurologic deficits (P = .013), and prolonged mechanical ventilatory support (P < .01). Midterm survival and freedom from major adverse cerebrocardiovascular events were worse across the levels of the lower categories of eGFR.

CONCLUSIONS

Preoperative eGFR is a strong predictor of short- and midterm outcomes in contemporary TAR.

The year in Cardiothoracic and Vascular Anesthesia: selected highlights from 2011

There have been rapid advances in oral anticoagulation. The oral factor Xa inhibitors rivaroxaban and apixaban and the oral direct thrombin inhibitor dabigatran recently have been rigorously evaluated. These novel anticoagulants will usher in a new paradigm for perioperative anticoagulation. Perioperative blood conservation in cardiac surgery recently has been highlighted in the updated guidelines by the Society of Cardiovascular Anesthesiologists and the Society of Thoracic Surgeons. These recommendations reflect a comprehensive evaluation of the recent evidence to optimize transfusion practice. Transcatheter mitral valve repair continues to mature. Transcatheter aortic valve implantation for aortic stenosis has entered the clinical mainstream, with randomized trials showing its superiority over medical management and its equivalency to surgical valve replacement in high-risk patients. This transformational technology represents a major leadership opportunity for the cardiac anesthesiologist. Minimally invasive valve surgery has shown effectiveness in high-risk patients. Radial access is equivalent to femoral access for percutaneous coronary intervention in acute coronary syndromes but significantly reduces the risk of local vascular complications. Recent trials have further clarified the roles of medical therapy, percutaneous coronary intervention, and coronary artery bypass surgery in patients with significant coronary artery disease and left ventricular dysfunction. The past year has witnessed major advances in cardiovascular practice with new drugs, new devices, and new guidelines. The coming year most likely will advance these achievements to enhance the care of patients.

Clinical and biochemical outcomes for additive mesenteric and lower body perfusion during hypothermic circulatory arrest for complex total aortic arch replacement surgery

Surgical repair of transverse aortic arch aneurysms frequently employ hypothermia and antegrade cerebral perfusion as protective strategies during circulatory arrest. However, prolonged mesenteric and lower limb ischemia can lead to significant lactic acidosis and end organ dysfunction, which remains a significant cause of post-operative morbidity and mortality. We report our experience with additive warm mesenteric and lower body perfusion (1-3 L/min, 30°C) in addition to continuous cerebral and myocardial perfusion in 5 patients who underwent total aortic arch replacement with trifurcated head vessel re-implantation and distal elephant trunk reconstruction. Concomitant surgical procedures included re-operations (2), aortic root operations (2), coronary artery bypass (2) and descending thoracic aortic replacement (1). Serum lactate levels demonstrated a rapid decline from a peak 9.9±2.6 post circulatory arrest to 3.4±2.0 in the intensive care unit (ICU). The lowest serum bicarbonate levels were 19.3±3.5 mmol/L, intra-operatively, which normalized to 28.4±2.4 mmol/L on return to the ICU. The lowest pH levels were 7.25±0.10, corrected to 7.43±0.04 on return to the ICU. Mean cardiopulmonary bypass and aortic cross-clamp times were 361±104 and 253±85 minutes, respectively. Mean cerebral and lower body circulatory arrest times were 0 (0) and 50±35 minutes, respectively. The mean time required for systemic rewarming was 95±66 minutes. There were no in-hospital mortalities and no patient experienced any neurological, mesenteric, renal or lower limb ischemic complications. Two patients required mechanical ventilation >24 hours, and one patient returned for reoperation for bleeding. Median intensive care unit and total hospital lengths of stay were 5 and 16 days, respectively. Our results suggest early serum lactate clearance, normalization of acidosis, and metabolic recovery when utilizing a simultaneous cerebral perfusion and warm body protection strategy for complex aortic arch surgery. This additive perfusion strategy may attenuate visceral and lower body ischemia that normally develops during periods of deep hypothermic circulatory arrest.

Incidence and risk factors of acute kidney injury after thoracic aortic surgery for acute dissection

BACKGROUND

Previous studies have reported a high incidence of acute kidney injury (AKI) after thoracic aortic surgery in heterogeneous patient cohorts, including various aortic diseases and the use of deep hypothermic circulatory arrest. Moderate hypothermia with cerebral perfusion makes deep hypothermia nonessential, but can make end organs susceptible to ischemia during circulatory arrest. We investigated the incidence and risk factors of AKI after thoracic aortic surgery with and without moderate hypothermic circulatory arrest for acute dissection.

METHODS

We reviewed the medical records of 98 patients undergoing graft replacement of the thoracic aorta for acute dissection between 2008 and 2011 at a university hospital. Acute kidney injury was defined by RIFLE criteria, which is based on serum creatinine or glomerular filtration rate.

RESULTS

The mean age was 55±15 years. The surgical procedures, 96% of which were emergencies, involved the ascending aorta (67%), aortic arch (41%), descending aorta (41%), and aortic valve (5%). Moderate hypothermic circulatory arrest was performed in 75%. The overall incidence of AKI was 54%, and 11% of 98 patients required renal replacement therapy. Thirty-day mortality increased with AKI severity (p=0.002). Independent risk factors for AKI were long cardiopulmonary bypass duration (>180 minutes; odds ratio, 7.50; p=0.008) and preoperative serum creatinine level (odds ratio, 8.43; p=0.016).

CONCLUSIONS

Acute kidney injury was common after thoracic aortic surgery for acute dissection with or without moderate hypothermic circulatory arrest and worsened 30-day mortality. Prolonged cardiopulmonary bypass and increased preoperative serum creatinine were independent risk factors for AKI, but moderate hypothermic circulatory arrest was not.

Acute kidney injury after composite valve-graft replacement for ascending aorta aneurysms

Acute kidney injury (AKI) following cardiac surgery is a continuing source of morbidity and mortality. Although several studies have attempted to determine its etiology and prophylactic measures, limited data exist after thoracic aortic surgery. The aim of this study was to evaluate the incidence and predictors of AKI in patients undergoing aortic root replacement (ARR) with valve conduit for ascending aorta aneurysms. A multi-center observational study of 414 patients undergoing ARR with a valve conduit was conducted, focusing on clinical outcome and AKI defined by consensus RIFLE (risk, injury, failure, loss of function, end-stage renal disease) criteria. Mean age was 62.5 years (range: 21-82 years) with 327 males (79%). Emergent operations were performed in 5% of the cases, while concomitant surgical procedures were performed in 24.9%. Postoperative AKI (all RIFLE classes) occurred in 69 (16.7%) patients, while eight (1.9%) required dialysis. Independent AKI predictors were packed red blood cells (pRBCs) >4 units (OR 2.28; 95% CI 1.20-4.30), cardiopulmonary bypass (CPB) time longer than 180 min (OR, 2.08; 95% CI, 1.16-3.73), and concomitant surgical procedures (OR, 1.85; 95% CI, 1.04-3.29). The severity of RIFLE class was associated with longer ICU stay, hospitalization, and higher hospital mortality (p < 0.001 for each variable). AKI after ARR operations with valve conduit for ascending aorta aneurysms increases utilization of health resources and is associated with adverse events. Concomitant surgical procedures, prolonged CPB-time, and pRBCs >4 units as independent AKI predictors merit further researches enhancing possible preventive strategies.

Cardiac catheterization within 1 to 3 days of proximal aortic surgery is not associated with increased postoperative acute kidney injury

OBJECTIVE

Cardiac catheterization shortly before coronary artery bypass grafting or valve surgery has been associated with increased postoperative acute kidney injury. The relationship between catheterization timing and acute kidney injury after proximal aortic surgery remains unknown.

METHODS

Between August 2005 and February 2011, a total of 285 consecutive patients underwent cardiac catheterization before elective proximal aortic surgery with cardiopulmonary bypass at a single institution. The association between timing of catheterization and postoperative acute kidney injury (defined as postoperative increase in serum creatinine ≥ 50% of baseline) was assessed using logistic regression analysis.

RESULTS

Of 285 patients, 152 (53%) underwent catheterization on preoperative days 1 to 3 and 133 (47%) underwent catheterization on preoperative day 4 or before. Acute kidney injury occurred in 88 (31%) patients, 3 (1.1%) requiring dialysis. Acute kidney injury occurred in 37 (24%) patients catheterized on preoperative days 1 to 3, and 51 (38%) patients catheterized on preoperative day 4 or before. Catheterization on preoperative days 1 to 3 was not associated with an increased risk of acute kidney injury relative to catheterization on preoperative day 4 or before (unadjusted odds ratio, 0.52; 95% confidence interval, 0.31-0.86; P = .01; adjusted odds ratio, 0.35; 95% confidence interval, 0.17-0.73; P = .005).

CONCLUSIONS

Cardiac catheterization within 1 to 3 days of elective proximal aortic surgery appears safe and should be considered acceptable practice for patients at low risk of acute kidney injury.

Impact of aprotinin and renal function on mortality: a retrospective single center analysis

BACKGROUND

An estimated up to 7% of high-risk cardiac surgery patients return to the operating room for bleeding. Aprotinin was used extensively as an antifibrinolytic agent in cardiac surgery patients for over 15 years and it showed efficacy in reducing bleeding. Aprotinin was removed from the market by the U.S. Food and Drug Administration after a large prospective, randomized clinical trial documented an increased mortality risk associated with the drug. Further debate arose when a meta-analysis of 211 randomized controlled trials showed no risk of renal failure or death associated with aprotinin. However, only patients with normal kidney function have been studied.

METHODS

In this study, we look at a single center clinical trial using patients with varying degrees of baseline kidney function to answer the question: Does aprotinin increase odds of death given varying levels of preoperative kidney dysfunction?

RESULTS

Based on our model, aprotinin use was associated with a 3.8-fold increase in odds of death one year later compared to no aprotinin use with p-value = 0.0018, regardless of level of preoperative kidney dysfunction after adjusting for other perioperative variables.

CONCLUSIONS

Lessons learned from our experience using aprotinin in the perioperative setting as an antifibrinolytic during open cardiac surgery should guide us in testing future antifibrinolytic drugs for not only efficacy of preventing bleeding, but for overall safety to the whole organism using long-term clinical outcome studies, including those with varying degree of baseline kidney function.

Acute kidney injury during aortic arch surgery under deep hypothermic circulatory arrest

PURPOSE

The aim of this investigation was to describe the renal outcome and to identify risk factors for acute kidney injury (AKI), as defined by the Acute Kidney Injury Network (AKIN), during aortic arch surgery (AAS) under deep hypothermic circulatory arrest (DHCA).

METHODS

A retrospective and observational study has been performed. One hundred thirty-five patients requiring AAS under DHCA were studied.

RESULTS

Seventy-one patients (52.6%) developed AKI during the postoperative period. A logistic regression analysis identified three independent risk factors for AKI: preoperative hypertension (HT), emergency surgery, and duration of DHCA. Renal replacement therapy (RRT) was required in four patients (3.0%). The postoperative mortality rate among the patients with AKI was 2.8%, which was not statistically different from the rate of 1.6% observed in the non-AKI group (P = 0.62).

CONCLUSIONS

A high incidence of AKI during AAS under DHCA was confirmed. Because AKI is highly associated with aortic surgery, novel approaches for protecting the kidneys other than deep hypothermia are needed. The logistic regression model identified HT, emergency surgery, and duration of DHCA as independent risk factors for AKI.

Renal Dysfunction Induced by Bacterial Infection other than Spontaneous Bacterial Peritonitis in Patients with Cirrhosis: Incidence and Risk Factor

Background/Aims

Deterioration of renal function in cirrhotic patients with spontaneous bacterial peritonitis (SBP) is a predictor for in-hospital mortality; however, the clinical significance of renal dysfunction during bacterial infection other than SBP is unknown. The aim of this study was to investigate the prevalence and clinical significance of renal dysfunction due to bacterial infections other than SBP in patients with liver cirrhosis.

Methods

Retrospective data from inpatients with bacterial infections other than SBP were analyzed.

Results

Eighty patients were recruited for the analysis. The types of infections included that of urinary tract (37.5%), pneumonia (23.8%), biliary tract (20%), cellulitis (12.5%), and bacteremia of unknown origin (6.3%). Renal dysfunction developed in 29 patients (36.3%), of which 11 patients had irreversible renal dysfunction. The initial MELD score, neutrophil count, albumin, and blood pressure were significant risk factors in the univariate analysis, whereas only the MELD score was an independent risk factor for the development of renal dysfunction (p<0.001) after multivariate analysis.

Conclusions

The prevalence of renal dysfunction during bacterial infection other than SBP in patients with liver cirrhosis was 36.3%, and its development was related to the severity of the liver disease. Occurrence of irreversible renal dysfunction seemed to affect the prognosis of these patients.

Preoperative and intraoperative risk factors for prolonged intensive care unit stay after aortic arch surgery

OBJECTIVE

The present study was performed to evaluate preoperative and intraoperative risk factors for prolonged intensive care unit (ICU) stay after aortic arch surgery.

DESIGN

A retrospective study. Prolonged ICU stay was defined as >5 days (120 hours).

SETTING

Cardiovascular operating rooms and the ICU.

PARTICIPANTS

Adults requiring aortic arch surgery with deep hypothermic circulatory arrest plus antegrade selective cerebral perfusion.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

After 11 patients who underwent 1-stage total or subtotal aortic replacement were excluded, 298 patients were enrolled in the study. The average age of patients was 44.9 +/- 10.7 years with male predominance (74.8%). Sixty-one patients (20.5%) stayed longer than 5 days in the ICU. Univariate analyses found age, body mass index, New York Heart Association classification, preoperative serum creatinine, creatinine clearance, emergency, inotropes, cardiopulmonary bypass time, myocardial ischemia time, and fresh-frozen plasma transfused intraoperatively were significantly associated with prolonged ICU stay (p < 0.05). Independent risk factors for prolonged ICU stay were found to be New York Heart Association classification (class III and IV), emergency, inotropes used intraoperatively, and prolonged cardiopulmonary bypass time (p < 0.05).

CONCLUSION

The authors identified 4 preoperative and intraoperative risk factors for prolonged ICU stay. This is helpful to identify patients with increased risk for prolonged ICU stay, implement specific strategies, and allocate medical resources.

Aprotinin and renal dysfunction

Aprotinin is a polypeptide serine protease inhibitor used to prevent bleeding and need for transfusions in patients having heart surgery. A recent analysis of an observational study data set suggested the use of aprotinin was associated with an increased risk of developing renal failure. The present article reviews the data from basic science studies in tissues, animals and man together with the data from observational studies and randomised controlled trials. The interpretation of the data is hampered owing to the use of different endpoints to describe mild/moderate renal impairment. Nonetheless, the evidence points to aprotinin use being associated with a transient small rise in plasma creatinine concentration in certain patients. There is no evidence for an increased risk of developing new renal failure requiring dialysis/renal replacement therapy.

RIFLE criteria for acute kidney injury in aortic arch surgery

OBJECTIVE

The RIFLE criteria are new international consensus definitions for acute kidney injury introduced to facilitate research across disciplines. We identified risk factors for acute kidney injury, renal replacement therapy, and mortality using the RIFLE criteria (RIFLE = risk, injury, failure, loss, end stage) in patients undergoing deep hypothermic circulatory arrest for aortic arch reconstruction.

METHODS

A single-center retrospective cohort study of 267 patients undergoing aortic arch surgery with deep hypothermic circulatory arrest was conducted between July 2001 and October 2005. Known predictors (age, chronic kidney disease, surgery status, redo, diabetes, hypertension, blood transfusion, bypass, and deep hypothermic circulatory arrest time) were used in multivariate logistic regression models for acute kidney injury, renal replacement therapy, and mortality.

RESULTS

Mean age was 64 years (range 23-89 years) with 166 men (62%). Seventy-five (28%) had RIFLE scores of I or F, and 22 (8%) required dialysis. Risk factors for acute kidney injury were hypertension (odds ratio [OR] = 2.17; 95% confidence intervals [CI], 1.14-4.15), chronic kidney disease (OR = 9.04; 95% CI, 1.97-41.59), packed red blood cells greater than 5 units (OR = 2.37; 95% CI, 1.20-4.69), and admission creatinine/Modification of Diet in Renal Disease predicted creatinine ratio greater than 1 (OR = 3.54; 95% CI, 1.95-6.45). Risk factors for mortality were age (per 10 years) (OR = 2.35; 95% CI, 1.35-4.06), AKI (RIFLE class R, I, or F) (OR = 4.60; 95% CI, 1.34-15.77), and cerebrovascular accident (OR = 19.1; 95% CI, 4.96-73.58). Mortality increased with each RIFLE stratification (RIFLE class 0 = 3%, R = 9%, I = 12%, and F = 38%).

CONCLUSIONS

Acute kidney injury as defined according to the RIFLE classification is a risk factor for mortality and will be useful in future studies of renal dysfunction in thoracic aortic surgery.

Aprotinin in Cardiac Surgery: A Review of Conventional and Novel Mechanisms of Action

Induction of the coagulation and inflammatory cascades can cause multiorgan dysfunction after cardiopulmonary bypass (CPB). In light of these observations, strategies that can stabilize the coagulation process as well as attenuate the inflammatory response during and after cardiac surgery are important. Aprotinin has effects on hemostasis. In addition, aprotinin may exert multiple biologically relevant effects in the context of cardiac surgery and CPB. For example, it decreases neutrophil and macrophage activation and chemotaxis, attenuates release and activation of proinflammatory cytokines, and reduces oxidative stress. Despite these perceived benefits, the routine use of aprotinin in cardiac surgery with CPB has been called into question. In this review, we examined this controversial drug by discussing the classical and novel pathways in which aprotinin may be operative in the context of cardiac surgery.

Atrial Fibrillation After Aortic Arch Repair Requiring Deep Hypothermic Circulatory Arrest: Incidence, Clinical Outcome, and Clinical Predictors

OBJECTIVE

To delineate the incidence, outcome impact, and clinical predictors of atrial fibrillation (AF) after adult aortic arch repair requiring deep hypothermic circulatory arrest (AAR-DHCA) AIMS: To determine the incidence of AF after AAR-DHCA, to determine whether AF after AAR-DHCA affects mortality or stay in the intensive care unit (ICU), to determine multivariate predictors for AF after AAR-DHCA, and to determine whether aprotinin protects against AF after AAR-DHCA.

STUDY DESIGN

Retrospective and observational.

STUDY SETTING

Single large university hospital.

PARTICIPANTS

All adults undergoing AAR-DHCA in 2000 and 2001.

MAIN RESULTS

The cohort size was 144. Antifibrinolytic exposure was 100%, aprotinin 66% and aminocaproic acid 34%. The incidence of AF was 34.0%. AF was not significantly associated with increased mortality or prolonged ICU stay. Advanced age was a multivariate risk factor for AF. Lower temperature nadir during DHCA was protective against postoperative AF. Aprotinin had no demonstrable effect on AF after AAR-DHCA.

CONCLUSIONS

AF after AAR-DHCA is common but does not independently increase mortality or ICU stay. The risk of AF after AAR-DHCA increases with age but decreases with the degree of hypothermia during DHCA. Aprotinin does not appear to affect the risk of AF after AAR-DHCA.