Predicting Hospital Mortality and Analysis of Long-Term Survival After Major Noncardiac Complications in Cardiac Surgery Patients

Is surgical risk of aortic arch aneurysm repair underestimated? A novel perspective based on 30-day versus 1-year mortality

OBJECTIVES

The decision to undergo aortic aneurysm repair balances the risk of operation with the risk of aortic complications. The surgical risk is typically represented by perioperative mortality, while the aneurysmal risk relates to the 1-year risk of aortic events. We investigate the difference in 30-day and 1-year mortality after total arch replacement for aortic aneurysm.

METHODS

This was an international two-centre study of 456 patients who underwent total aortic arch replacement for aneurysm between 2006 and 2020. Our primary end-point of interest was 1-year mortality. Our secondary analysis determined which variables were associated with 1-year mortality.

RESULTS

The median age of patients was 65.4 years (interquartile range 55.1-71.1) and 118 (25.9%) were female. Concomitantly, 91 (20.0%) patients had either an aortic root replacement or aortic valve procedure. There was a drop in 1-year (81%, 95% confidence interval (CI) 78-85%) survival probability compared to 30-day (92%, 95% CI 90-95%) survival probability. Risk hazards regression showed the greatest risk of mortality in the first 4 months after discharge. Stroke [hazard ratio (HR) 2.54, 95% CI (1.16-5.58)], renal failure [HR 3.59 (1.78-7.25)], respiratory failure [HR 3.65 (1.79-7.42)] and reoperation for bleeding [HR 2.97 (1.36-6.46)] were associated with 1-year mortality in patients who survived 30 days.

CONCLUSIONS

There is an increase in mortality up to 1 year after aortic arch replacement. This increase is prominent in the first 4 months and is associated with postoperative complications, implying the influence of surgical insult. Mortality beyond the short term may be considered in assessing surgical risk in patients who are undergoing total arch replacement.

Percutaneous dilatation tracheotomy in patients on extracorporeal membrane oxygenation after cardiac surgery

BACKGROUND

Current practices regarding percutaneous dilatational tracheostomy in adult patients treated with extracorporeal membrane oxygenation (ECMO) after cardiac surgery is not completely defined. This study aimed to evaluate the safety of the percutaneous dilatational tracheostomy in patients with ECMO after cardiac surgery.

METHODS

Between July 2017 and May 2021, 371 ECMO procedures were performed in more than 35,000 adult patients who underwent cardiac surgery in our hospital. Sixty-two patients underwent percutaneous dilatational tracheostomy (PDT) during or after ECMO. A retrospective analysis was performed comparing the incidence of complications and clinical outcomes of the two groups.

RESULTS

Of the 371 patients treated with ECMO after adult cardiac surgery during the enrollment period, 22 (7.1%) and 40 (12.8%) underwent PDT during or after ECMO, respectively. The platelet count (PLT) of the day was significantly lower in the PDT during ECMO group (54 (34, 68) vs. 108 (69, 162) (thousands), p < 0.001)). The prothrombin time (PT) and activated partial thromboplastin time (APTT) of the day were longer in the PDT during ECMO group (15.8 (14.6, 19.9) vs. 13.8 (13.2, 15.2) seconds, p = 0.001, 43.8 (38.0, 49.4) vs. 35.2 (28.2, 40.9) seconds, p < 0.001, respectively). There was no significant difference in tracheotomy-related complications between the two groups. Significantly decreased ventilator time was observed in the PDT during ECMO group.

CONCLUSIONS

Despite poor coagulation of the day, PDT during ECMO is safe and can appropriately reduce the duration of mechanical ventilation compared with PDT after ECMO weaning in adult patients who have undergone cardiac surgery.

Impact of postoperative complications after cardiac surgery on long-term survival

PURPOSE

The impact of postoperative complications on long-term survival is not well characterized. We sought to study the prevalence of postoperative complications after cardiac surgery and their impact on long-term survival.

METHODS

Operative survivors (n = 26,221) who underwent coronary artery bypass grafting (CABG) (n = 13,054, 49.8%), valve surgery (n = 8667, 33.1%) or combined CABG and valve surgery (n = 4500, 17.2%) from 1993 to 2019 were included in the study. Records were reviewed for postoperative complications and long-term survival. Propensity-match analysis was performed between patients who did and did not have a postoperative complication. The associations between postoperative complications and survival were assessed using a Cox-proportional model.

RESULTS

Complications occurred in 17,463 (66.6%) of 26,221 operative survivors. A total of 17 postoperative complications were analyzed. Postoperative blood product use was the commonest (n = 12,397, 47.3%), followed by atrial fibrillation (n = 8399, 32.0%), prolonged ventilation (n = 2336, 8.9%), renal failure (n = 870, 3.3%), reoperation for bleeding (n = 859, 3.3%) and pacemaker/ICD insertion (n = 795, 3.0%). Stroke (hazard ratio [HR]: 1.55; 95% confidence interval [CI]: 1.36-1.77), renal failure (HR: 1.45; 95% CI: 1.33-1.58) and pneumonia (HR: 1.23; 95% CI: 1.11-1.36) had the strongest impact on long-term survival. Long-term survival decreased as the number of postoperative complications increased.

CONCLUSIONS

Postoperative complications after cardiac surgery significantly impact outcomes that extend beyond the postoperative period. Stroke, renal failure, and pneumonia are particularly associated with poor long-term survival.

The influence of postoperative albumin levels on the outcome of cardiac surgery

BACKGROUND

The prognostic role of low postoperative serum albumin levels (SAL) after cardiac surgery (CS) remains unclear in patients with normal preoperative SAL. Our aim was to evaluate the influence of SAL on the outcome of CS.

METHODS

Prospective observational study. Patients undergoing CS with normal preoperative SAL and nutritional status were included and classified into different subgroups based on SAL at 24 h after CS. We assessed outcomes (i.e., in-hospital mortality, postoperative complications and long-term survival) and results were analyzed among the different subgroups of SAL.

RESULTS

We included 2818 patients. Mean age was 64.5 ± 11.6 years and body mass index 28.0 ± 4.3Kg·m^- 2. 5.8%(n = 162) of the patients had normal SAL levels(≥35 g·L^- 1), 32.8%(n = 924) low deficit (30-34.9 g·L^- 1), 44.3%(n = 1249) moderate deficit (25-29.9 g·L^- 1), and 17.1%(n = 483) severe deficit(< 25 g·L^- 1). Higher SAL after CS was associated with reduced in-hospital (OR:0.84;95% CI:0.80-0.84; P = 0.007) and long-term mortality (HR:0.85;95% CI:0.82-0.87;P < 0.001). Subgroups of patients with lower SAL showed worst long-term survival (5-year mortality:94.3% normal subgroup, 87.4% low, 83.1% moderate and 72.4% severe;P < 0.001). Multivariable analysis showed higher in-hospital mortality, sepsis, hemorrhage related complications, and ICU stay in subgroups of patients with lower SAL. Predictors of moderate and severe hypoalbuminemia were preoperative chronic kidney disease, previous CS, and longer cardiopulmonary bypass time.

CONCLUSIONS

The presence of postoperative hypoalbuminemia after CS is frequent and the degree of hypoalbuminemia may be associated with worst outcomes, even in the long-term scenario.

Structured review of post-cardiotomy extracorporeal membrane oxygenation: part 1-Adult patients

Cardiogenic shock, cardiac arrest, acute respiratory failure, or a combination of such events, are all potential complications after cardiac surgery which lead to high mortality. Use of extracorporeal temporary cardio-circulatory and respiratory support for progressive clinical deterioration can facilitate bridging the patient to recovery or to more durable support. Over the last decade, extracorporeal membrane oxygenation (ECMO) has emerged as the preferred temporary artificial support system in such circumstances. Many factors have contributed to widespread ECMO use, including the relative ease of implantation, effectiveness, versatility, low cost relative to alternative devices, and potential for full, not just partial circulatory support. While there have been numerous publications detailing the short and midterm outcomes of ECMO support, specific reports about post-cardiotomy ECMO (PC-ECMO), are limited, single-center experiences. Etiology of cardiorespiratory failure leading to ECMO implantation, associated ECMO complications, and overall patient outcomes may be unique to the PC-ECMO population. Despite the rise in PC-ECMO use over the past decade, short-term survival has not improved. This report, therefore, aims to present a comprehensive overview of the literature with respect to the prevalence of ECMO use, patient characteristics, ECMO management, and in-hospital and early post-discharge patient outcomes for those treated for post-cardiotomy heart, lung, or heart-lung failure.

Structured review of post-cardiotomy extracorporeal membrane oxygenation: Part 2-pediatric patients

Veno-arterial extracorporeal membrane oxygenation (ECMO) is established therapy for short-term circulatory support for children with life-treating cardiorespiratory dysfunction. In children with congenital heart disease (CHD), ECMO is commonly used to support patients with post-cardiotomy shock or complications including intractable arrhythmias, cardiac arrest, and acute respiratory failure. Cannulation configurations include central, when the right atrium and aorta are utilized in patients with recent sternotomy, or peripheral, when cannulation of the neck or femoral vessels are used in non-operative patients. ECMO can be used to support any form of cardiac disease, including univentricular palliated circulation. Although veno-arterial ECMO is commonly used to support children with CHD, veno-venous ECMO has been used in selected patients with hypoxemia or ventilatory failure in the presence of good cardiac function. ECMO use and outcomes in the CHD population are mainly informed by single-center studies and reports from collated registry data. Significant knowledge gaps remain, including optimal patient selection, timing of ECMO deployment, duration of support, anti-coagulation, complications, and the impact of these factors on short- and long-term outcomes. This report, therefore, aims to present a comprehensive overview of the available literature informing patient selection, ECMO management, and in-hospital and early post-discharge outcomes in pediatric patients treated with ECMO for post-cardiotomy cardiorespiratory failure.

Mediastinitis in open heart surgery: a systematic review and meta-analysis of risk factors

Objective. We aimed to summarize the evidence from observational studies examining the risk factors of the incidence of mediastinitis in open heart surgery. Design. The study was a systematic review and meta-analysis of cohorts and case-control studies. Material and methods. We searched the literature and 74 studies with at least one risk factor were identified. Both fixed and random effects models were used. Heterogeneity between studies was examined by subgroup and meta-regression analysis. Publication bias or small study effects were evaluated and corrected by limit meta-analysis. Results. When correcting for small study effect, presence of obesity as estimated from 43 studies had Odds Ratio OR = 2.26. (95% CI: 2.17-2.36). This risk was increasing with decreasing latitude of study place. Presence of diabetes mellitus from 63 studies carried an OR = 1.90 (95% CI: 1.59-2.27). Presence of Chronic Obstructive Pulmonary Disease (COPD) from 30 studies had an OR = 2.59 (95% CI: 2.22-2.85). Presence of bilateral intramammary graft (BIMA) from 23 studies carried an OR = 2.54 (95% CI: 2.07-3.13). This risk was increasing with increasing frequency of female patients in the study population. Conclusion. Evidence from this study showed the robustness of the risk factors in the pathogenesis of mediastinitis. Preventive measures can be implemented for reducing obesity, especially in lower latitude countries. Furthermore, it is mandatory to monitor perioperative hyperglycemias with continuous insulin infusion. Use of skeletonized BIMA carries higher risk of mediastinitis especially in female patients without evidence of beneficial effect on survival for the time being.

Med-Score 24: A multivariable prediction model for poststernotomy mediastinitis 24 hours after admission to the intensive care unit

OBJECTIVES

Mediastinitis is a serious complication of heart surgery. In this study, we developed a bedside risk score for poststernotomy mediastinitis.

METHODS

Data were prospectively collected from 4625 patients admitted to our intensive care unit after heart surgery (January 2005-June 2011). Mediastinitis was defined according to Centers for Disease Control and Prevention criteria. A logistic model was constructed in a randomly selected subgroup of 2618 patients and validated in a second cohort of 1352, as well as in a prospective cohort of 2615 (June 2011-December 2015). Model discriminatory power was assessed according to the area under the receiver operating characteristic curve (AUROC). The β coefficients of the model were used to define 3 levels of mediastinitis risk as a score designated Med-Score 24. Its performance to predict mediastinitis was compared with that of the logistic EuroSCORE and Society of Thoracic Surgeons score.

RESULTS

Ninety-four (2.36%) patients developed mediastinitis. The risk factors identified as predictive of mediastinitis (AUROC 0.80) were 4 preoperative variables (age >70 years, chronic obstructive lung disease, obesity, and antiplatelet therapy) and 3 perioperative variables (prolonged ischemia, emergency reoperation, and prolonged intubation). AUROCs for the Society of Thoracic Surgeons score and logistic EuroSCORE were 0.63 and 0.55, respectively, both differing significantly from the area calculated for Med-Score 24 (P < .001).

CONCLUSIONS

The score developed showed excellent predictive power 24 hours after admission to the intensive care unit for mediastinitis risk. This simple tool helps stratify patients according to this risk, thus identifying high-risk patients for preventive measures. In our patient cohort, Med-Score 24 performed better than other scores used for this purpose.

Latitude of the study place and age of the patient are associated with incidence of mediastinitis and microbiology in open-heart surgery: a systematic review and meta-analysis

Objective

We aimed to summarize the pooled frequency of mediastinitis following open-heart surgery caused by Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), and Gram-negative bacteria.

Design

This study was a systematic review and a meta-analysis of prospective and retrospective cohort studies.

Materials and methods

We searched the literature, and a total of 97 cohort studies were identified. Random-effect model was used to synthesize the results. Heterogeneity between studies was examined by subgroup and meta-regression analyses, considering study and patient-level variables. Small-study effect was evaluated.

Results

Substantial heterogeneity was present. The estimated incidence of mediastinitis evaluated from 97 studies was 1.58% (95% confidence intervals [CI] 1.42, 1.75) and that of Gram-positive bacteria, Gram-negative bacteria, and MRSA bacteria evaluated from 63 studies was 0.90% (95% CI 0.81, 1.21), 0.24% (95% CI 0.18, 0.32), and 0.08% (95% CI 0.05, 0.12), respectively. A meta-regression pinpointed negative association between the frequency of mediastinitis and latitude of study place and positive association between the frequency of mediastinitis and the age of the patient at operation. Multivariate meta-regression showed that prospective cohort design and age of the patients and latitude of study place together or in combination accounted for 17% of heterogeneity for end point frequency of mediastinitis, 16.3% for Gram-positive bacteria, 14.7% for Gram-negative bacteria, and 23.3% for MRSA bacteria.

Conclusion

Evidence from this study suggests the importance of latitude of study place and advanced age as risk factors of mediastinitis. Latitude is a marker of thermally regulated bacterial virulence and other local surgical practice. There is concern of increasing risk of mediastinitis and of MRSA in elderly patients undergoing sternotomy.

Comparison of the non-invasive Nexfin® monitor with conventional methods for the measurement of arterial blood pressure in moderate risk orthopaedic surgery patients

Objective

Continuous invasive arterial blood pressure (IBP) monitoring remains the gold standard for BP measurement, but traditional oscillometric non-invasive intermittent pressure (NIBP) measurement is used in most low-to-moderate risk procedures. This study compared non-invasive continuous arterial BP measurement using a Nexfin® monitor with NIBP and IBP monitors.

Methods

This was a single-centre, prospective, pilot study in patients scheduled for elective orthopaedic surgery. Systolic BP, diastolic BP and mean arterial blood pressure (MAP) were measured by Nexfin®, IBP and NIBP at five intraoperative time-points. Pearson correlation coefficients, Bland–Altman plots and trending ability of Nexfin® measurements were used as criteria for success in the investigation of measurement reliability.

Results

A total of 20 patients were enrolled in the study. For MAP, there was a sufficient correlation between IBP/Nexfin® (Pearson = 0.75), which was better than the correlation between IBP/NIBP (Pearson = 0.70). Bland–Altman analysis of the data showed that compared with IBP, there was a higher percentage error for MAP_NIBP (30%) compared with MAP_Nexfin® (27%). Nexfin® and NIBP underestimated systolic BP; NIBP also underestimated diastolic BP and MAP. Trending ability for MAP_Nexfin® and MAP_NIBP were comparable to IBP.

Conclusion

Non-invasive BP measurement with Nexfin® was comparable with IBP and tended to be more precise than NIBP.

The influence of body mass index on outcomes in patients undergoing cardiac surgery: does the obesity paradox really exist?

Purpose

Obesity influences risk stratification in cardiac surgery in everyday practice. However, some studies have reported better outcomes in patients with a high body mass index (BMI): this is known as the obesity paradox. The aim of this study was to quantify the effect of diverse degrees of high BMI on clinical outcomes after cardiac surgery, and to assess the existence of an obesity paradox in our patients.

Methods

A total of 2,499 consecutive patients requiring all types of cardiac surgery with cardiopulmonary bypass between January 2004 and February 2009 were prospectively studied at our institution. Patients were divided into four groups based on BMI: normal weight (18.5–24.9 kg∙m⁻²; n = 523; 21.4%), overweight (25–29.9kg∙m⁻²; n = 1150; 47%), obese (≥30–≤34.9kg∙m⁻²; n = 624; 25.5%) and morbidly obese (≥35kg∙m⁻²; n = 152; 6.2%). Follow-up was performed in 2,379 patients during the first year.

Results

After adjusting for confounding factors, patients with higher BMI presented worse oxygenation and better nutritional status, reflected by lower PaO₂/FiO₂ at 24h and higher albumin levels 48h after admission respectively. Obese patients showed a higher risk for Perioperative Myocardial Infarction (OR: 1.768; 95% CI: 1.035–3.022; p = 0.037) and septicaemia (OR: 1.489; 95% CI: 1.282–1.997; p = 0.005). In-hospital mortality was 4.8% (n = 118) and 1-year mortality was 10.1% (n = 252). No differences were found regarding in-hospital mortality between BMI groups. The overweight group showed better 1-year survival than normal weight patients (91.2% vs. 87.6%; Log Rank: p = 0.029. HR: 1.496; 95% CI: 1.062–2.108; p = 0.021).

Conclusions

In our population, obesity increases Perioperative Myocardial Infarction and septicaemia after cardiac surgery, but does not influence in-hospital mortality. Although we found better 1-year survival in overweight patients, our results do not support any protective effect of obesity in patients undergoing cardiac surgery.

Preoperative hydroperoxide concentrations are associated with a risk of postoperative complications after cardiac surgery

This study aimed to assess whether preoperative oxidative stress levels can predict postoperative complications in patients undergoing cardiac surgery. Ninety-five cardiac surgery patients received an assessment of preoperative oxidative stress by measurement of hydroperoxide values in blood via the d-Rom test. Area under the receiver operating characteristic curve and also multivariate logistic regression were used to evaluate the prognostic significance of preoperative hydroperoxide concentrations in predicting the occurrence of major organ morbidity and mortality (MOMM). MOMM included death, deep sternal infection, reoperation, stroke, renal failure requiring haemodialysis and prolonged ventilation (>48 hours). The ability of preoperative hydroperoxide concentrations to predict MOMM was not significantly different from that of the European system for cardiac operative risk evaluation (EuroSCORE) (area under the receiver operating characteristic curve 0.822 versus 0.821 respectively, P=0.983). The optimal threshold value of hydroperoxide concentration to differentiate between patients with and without MOMM was 450 UCarr (sensitivity, 87.0%; specificity, 81.9%). Duration of intensive care unit stay, mechanical ventilation time and hospital stay were significantly longer in patients with preoperative hydroperoxide concentrations ≥450 UCarr (H group) compared to those patients with preoperative hydroperoxide concentrations <450 UCarr (L group). An increase in preoperative hydroperoxide concentrations remained associated with an increased risk of MOMM (odds ratios: 1.01, 95% confidence interval: 1.00 to 1.03) and prolonged intensive care unit stay (odds ratio 1.01, 95% confidence interval: 1.00 to 1.02), after adjusting for age, gender and EuroSCORE. In conclusion, an increased hydroperoxide concentration before cardiac surgery is an independent risk factor for severe postoperative complications.

Impact of hospital infections on patients outcomes undergoing cardiac surgery at Santa Casa de Misericórdia de Marília

Objective

this study aimed to determine the incidence of nosocomial infections, the risk factors and the impact of these infections on mortality among patients undergoing to cardiac surgery.

Methods

Retrospective cohort study of 2060 consecutive patients from 2006 to 2012 at the Santa Casa de Misericórdia de Marília.

Results

351 nosocomial infections were diagnosed (17%), 227 non-surgical infections and 124 surgical wound infections. Major infections were mediastinitis (2.0%), urinary tract infection (2.8%), pneumonia (2.3%), and bloodstream infection (1.7%). The in-hospital mortality was 6.4%. Independent variables associated with non-surgical infections were age > 60 years (OR 1.59, 95% CI 1.09 to 2.31), ICU stay > 2 days (OR 5, 49, 95% CI 2.98 to 10, 09), mechanical ventilation > 2 days (OR11, 93, 95% CI 6.1 to 23.08), use of urinary catheter > 3 days (OR 4.85 95% CI 2.95 -7.99). Non-surgical nosocomial infections were more frequent in patients with surgical wound infection (32.3% versus 7.2%, OR 6.1, 95% CI 4.03 to 9.24). Independent variables associated with mortality were age greater than 60 years (OR 2.0; 95% CI 1.4 to3.0), use of vasoactive drugs (OR 3.4, 95% CI 1.9 to 6, 0), insulin use (OR 1.8; 95% CI 1.2 to 2.8), surgical reintervention (OR 4.4; 95% CI 2.1 to 9.0) pneumonia (OR 4.3; 95% CI 2.1 to 8.9) and bloodstream infection (OR = 4.7, 95% CI 2.0 to 11.2).

Conclusion

Non-surgical hospital infections are common in patients undergoing cardiac surgery; they increase the chance of surgical wound infection and mortality.

Percutaneous Tracheostomy Can be Safely Performed in Patients with Uncorrected Coagulopathy after Cardiothoracic Surgery

Objective

It is a common situation after cardiothoracic surgery that a tracheostomy is required for patients who are coagulopathic or on therapeutic anticoagulation. We present our results of percutaneous tracheostomy with uncorrected coagulopathy.

Methods

Between 2007 and 2012, a total of 149 patients in our Cardiothoracic Surgical Intensive Care Unit underwent percutaneous tracheostomy using the Ciaglia Blue Rhino system (Cook Medical, Bloomington, IN USA). The patients were divided into coagulopathic (platelets, ≤50,000; international normalized ratio of prothrombin time, ≥1.5; and/or partial thromboplastin time, ≥50) and noncoagulopathic groups. Coagulopathy, if present before percutaneous tracheostomy, was not routinely corrected.

Results

A total of 75 patients (49%) were coagulopathic. Twenty-one patients (14%) had two or more criteria. The coagulopathic patients had a lower platelet count [108 (106) vs 193 (111) (thousands), P < 0.001], with the lowest of 10; higher international normalized ratio of prothrombin time [1.7 (0.6) vs 1.2 (0.1), P < 0.001], with the highest of 5.3; longer partial thromboplastin time [40 (13) vs 33 (7) seconds, P < 0.001], with the longest of 85; and higher total bilirubin [4.6 (7.3) vs 1.9 (3.3) mg/dL, P = 0.005]. Patient demographics and comorbidities were comparable between the groups. No patients had overt bleeding. One coagulopathic patient (1.3%) had clinical oozing treated with packing, as opposed to zero in the noncoagulopathic patients ( P = 1.00). There were no patients with posttracheostomy mediastinitis or late tracheal stenosis.

Conclusions

Uncorrected coagulopathy and therapeutic anticoagulation did not increase bleeding risk for percutaneous tracheostomy in our cardiothoracic surgical patients.

Influence of acute kidney injury on short- and long-term outcomes in patients undergoing cardiac surgery: risk factors and prognostic value of a modified RIFLE classification

INTRODUCTION

The development of acute kidney injury (AKI) is associated with poor outcome. The modified RIFLE (risk, injury, failure, loss of kidney function, and end-stage renal failure) classification for AKI, which classifies patients with renal replacement therapy needs according to RIFLE failure class, improves the predictive value of AKI in patients undergoing cardiac surgery. Our aim was to assess risk factors for post-operative AKI and the impact of renal function on short- and long-term survival among all AKI subgroups using the modified RIFLE classification.

METHODS

We prospectively studied 2,940 consecutive cardiosurgical patients between January 2004 and July 2009. AKI was defined according to the modified RIFLE system. Pre-operative, operative and post-operative variables usually measured on and during admission, which included main outcomes, were recorded together with cardiac surgery scores and ICU scores. These data were evaluated for association with AKI and staging in the different RIFLE groups by means of multivariable analyses. Survival was analyzed via Kaplan-Meier and a risk-adjusted Cox proportional hazards regression model. A complete follow-up (mean 6.9 ± 4.3 years) was performed in 2,840 patients up to April 2013.

RESULTS

Of those patients studied, 14% (n = 409) were diagnosed with AKI. We identified one intra-operative (higher cardiopulmonary bypass time) and two post-operative (a longer need for vasoactive drugs and higher arterial lactate 24 hours after admission) predictors of AKI. The worst outcomes, including in-hospital mortality, were associated with the worst RIFLE class. Kaplan-Meier analysis showed survival of 74.9% in the RIFLE risk group, 42.9% in the RIFLE injury group and 22.3% in the RIFLE failure group (P <0.001). Classification at RIFLE injury (Hazard ratio (HR) = 2.347, 95% confidence interval (CI) 1.122 to 4.907, P = 0.023) and RIFLE failure (HR = 3.093, 95% CI 1.460 to 6.550, P = 0.003) were independent predictors for long-term patient mortality.

CONCLUSIONS

AKI development after cardiac surgery is associated mainly with post-operative variables, which ultimately could lead to a worst RIFLE class. Staging at the RIFLE injury and RIFLE failure class is associated with higher short- and long-term mortality in our population.

Evaluating the obtunded patient after cardiac surgery: the role of continuous electroencephalography

PURPOSE

This prospective study was designed to evaluate the role of continuous electroencephalography (EEG) in the management of adult patients with neurological dysfunction early after cardiac surgery.

MATERIALS AND METHODS

Seven hundred twenty-three patients undergoing cardiac surgery between December 2010 and June 2011 were divided into 2 groups based on the presence or absence of post-operative neurological dysfunction. All patients with neurological dysfunction underwent continuous EEG.

RESULTS

Neurological dysfunction was diagnosed in 12 patients (1.7%), of whom 5 (42%) did not regain consciousness after surgery, 4 (33%) had a clinical event suspicious for seizure and 3 (25%) had neurological deficits. Continuous EEG showed that 2 of the 5 patients who failed to regain consciousness, without clinical signs of seizures, were in electrographic non-convulsive focal status epilepticus. Periodic discharges were present in the continuous EEGs of 3 patients. Three additional patients (25%) had abnormal movements that continuous EEG demonstrated was not due to seizure activity.

CONCLUSIONS

Non-convulsive status epilepticus may be an under-recognized cause of obtundation early after cardiac surgery. Continuous EEG monitoring is a non-invasive test that can identify patients that may benefit from anti-epileptic medication. Larger comparative studies are required to establish whether this leads to significant improvements in patient outcomes.

Impact of major non-cardiac complications on outcome following cardiac surgery procedures: logistic regression analysis in a very recent patient cohort

OBJECTIVES

In this study, we sought to analyse the incidence of major non-cardiac complications and their impact on survival following cardiac surgery procedures in a contemporary patient cohort. We further determined independent predictors of perioperative mortality and created a logistic regression model for prediction of outcome after the occurrence of these complications.

METHODS

Prospectively collected data of 5318 consecutive adult patients (mean age 68.9±11.0 years; 29.3% [n=1559] female) undergoing cardiac surgery from January 2009 to May 2012 were retrospectively analysed. Outcome measures were six major non-cardiac complications including respiratory failure, dialysis-dependent renal failure, deep sternal wound infection (DSWI), cerebrovascular accident (CVA), gastrointestinal complications (GIC) and sepsis and their impact on perioperative mortality and hospital length of stay using multivariate regression models. The discriminatory power was evaluated by calculating the area under the receiver operating characteristic curves (C statistic).

RESULTS

A total of 1321 complications were observed in 846 (15.9%) patients: respiratory failure (n=432; 8.1%), dialysis-dependent renal failure (n=295; 5.5%), GIC (n=154; 2.9%), CVA (n=151; 2.8%), DSWI (n=146; 2.7%) and sepsis (n=143; 2.7%). Perioperative mortality was 17.0% in patients with at least one major non-cardiac complication and correlated with the number of complications (single, 9.7%; n=53/549; double, 24.0%; n=44/183; ≥3, 41.2%; n=47/114, P<0.001). Six preoperative and four postoperative independent predictors of operative mortality were identified (age (odds ratio [OR] 1.8; 95% confidence interval [CI] 1.3-2.4), peripheral vascular disease (OR 2.6; 95% CI 1.6-4.2), pulmonary hypertension (OR 2.7; 95% CI 1.5-4.9), atrial fibrillation (OR 1.5; 95% CI 1.0-2.3), emergency (OR 5.0; 95% CI 3.4-7.2), other procedures than CABG (OR 1.5; 95% CI 1.0-2.1), postoperative dialysis (OR 4.0; 95% CI 2.6-6.1), sepsis (OR 3.4; 95% CI 2.0-5.6), respiratory failure (OR 3.2; 95% CI 2.2-4.9), GIC (OR 3.2; 95% CI 1.9-5.3)) and included in the logistic model, which accurately predicted outcome (C statistic, 0.892; 95% CI 0.868-0.916). Length of hospital stay was significantly increased according to the number of complications (single: median 15 (IQR 10-24) days, double: 16 (IQR 8-28) days, ≥3: 20 (IQR 13-39) days, P<0.001).

CONCLUSIONS

With a worsening in the risk profile of patients undergoing cardiac surgery, an increasing number of patients develop major complications leading to increased length of stay and mortality, which is correlated to the number and severity of these complications. Our predictive model based on preoperative and postoperative variables allowed us to determine with accuracy the perioperative mortality in critically ill patients after cardiac surgery.

Delirium in the cardiovascular ICU: exploring modifiable risk factors

OBJECTIVE

Delirium, an acute organ dysfunction, is common among critically ill patients leading to significant morbidity and mortality; its epidemiology in a mixed cardiology and cardiac surgery ICU is not well established. We sought to determine the prevalence and risk factors for delirium among cardiac surgery ICU patients.

DESIGN

Prospective observational study.

SETTING

Twenty-seven-bed medical-surgical cardiac surgery ICU.

PATIENTS

Two hundred consecutive patients with an expected cardiac surgery ICU length of stay >24 hrs.

INTERVENTIONS

None.

MEASUREMENTS

Baseline demographic data and daily assessments for delirium using the validated and reliable Confusion Assessment Method for the ICU were recorded, and quantitative tracking of delirium risk factors were conducted. Separate analyses studied the role of admission risk factors for occurrence of delirium during the cardiac surgery ICU stay and identified daily occurring risk factors for the development of delirium on a subsequent cardiac surgery ICU day.

MAIN RESULTS

Prevalence of delirium was 26%, similar among cardiology and cardiac surgical patients. Nearly all (92%) exhibited the hypoactive subtype of delirium. Benzodiazepine use at admission was independently predictive of a three-fold increased risk of delirium (odds ratio 3.1 [1, 9.4], p = 0.04) during the cardiac surgery ICU stay. Of the daily occurring risk factors, patients who received benzodiazepines (2.6 [1.2, 5.7], p = 0.02) or had restraints or devices that precluded mobilization (2.9 [1.3, 6.5], p < 0.01) were more likely to have delirium the following day. Hemodynamic status was not associated with delirium.

CONCLUSIONS

Delirium occurred in one in four patients in the cardiac surgery ICU and was predominately hypoactive in subtype. Chemical restraints via use of benzodiazepines or the use of physical restraints/restraining devices predisposed patients to a greater risk of delirium, pointing to areas of quality improvement that would be new to the vast majority of cardiac surgery ICUs.

The impact of frailty status on survival after transcatheter aortic valve replacement in older adults with severe aortic stenosis: a single-center experience

OBJECTIVES

This study sought to evaluate the impact of frailty in older adults undergoing transcatheter aortic valve replacement (TAVR) for symptomatic aortic stenosis.

BACKGROUND

Frailty status impacts prognosis in older adults with heart disease; however, the impact of frailty on prognosis after TAVR is unknown.

METHODS

Gait speed, grip strength, serum albumin, and activities of daily living status were collected at baseline and used to derive a frailty score among patients who underwent TAVR procedures at a single large-volume institution. The cohort was dichotomized on the basis of median frailty score into frail and not frail groups. The impact of frailty on procedural outcomes (stroke, bleeding, vascular complications, acute kidney injury, and mortality at 30 days) and 1-year mortality was evaluated.

RESULTS

Frailty status was assessed in 159 subjects who underwent TAVR (age 86 ± 8 years, Society of Thoracic Surgery Risk Score 12 ± 4). Baseline frailty score was not associated with conventionally ascertained clinical variables or Society of Thoracic Surgery score. Although high frailty score was associated with a longer post-TAVR hospital stay when compared with lower frailty score (9 ± 6 days vs. 6 ± 5 days, respectively, p = 0.004), there were no significant crude associations between frailty status and procedural outcomes, suggesting adequacy of the standard selection process for identifying patients at risk for periprocedural complications after TAVR. Frailty status was independently associated with increased 1-year mortality (hazard ratio: 3.5, 95% confidence interval: 1.4 to 8.5, p = 0.007) after TAVR.

CONCLUSIONS

Frailty was not associated with increased periprocedural complications in patients selected as candidates to undergo TAVR but was associated with increased 1-year mortality after TAVR. Further studies will evaluate the independent value of this frailty composite in older adults with aortic stenosis.

Established preoperative risk factors do not predict long-term survival in isolated coronary artery bypass grafting patients

BACKGROUND

Use of isolated coronary artery bypass grafting (CABG) is expected to increase as the population ages. Short-term adverse outcomes models and their application to the decision-making process have greatly increased the safety and effectiveness of CABG. However, similar tools addressing long-term survival have not been developed. We examined the effect of the preoperative risk factors included in short-term outcomes models on long-term survival in patients who survive CABG.

METHODS

A Cox survival model considering preoperative risk factors identified by The Society of Thoracic Surgeons was developed for 8,529 consecutive patients who underwent isolated CABG between January 1, 1997, and August 31, 2010, at Baylor University Medical Center (Dallas, Texas) and were alive 30-days post-CABG.

RESULTS

There were 2,388 (27.9%) deaths during follow-up (≤14 years). Unadjusted survival was 83.8% and 65% at 5 and 10 years, respectively. The Cox model showed that most established preoperative risk factors were significantly associated with survival. Their effect was minimal, however; the variation explained by their cumulative effect in predicting survival was 16.8% (R2=0.168).

CONCLUSIONS

Established operative risk factors may not be good predictors of long-term post-CABG survival. Late mortality may be attributable to many causes, not necessarily related to patients' cardiovascular and general health at the time of operation. Discussions with cardiothoracic surgeons and long-term shared decision making with primary care physicians/cardiologists should therefore not focus solely on patients' preoperative risk profile but should also emphasize the importance of preventing/controlling other diseases through a healthy lifestyle and compliance with disease management protocols.

Gait speed and dependence in activities of daily living in older adults with severe aortic stenosis

BACKGROUND

In the transcatheter aortic valve replacement era, characterization of functional status in older adults with aortic stenosis (AS) is essential. Gait speed (GS) is emerging as a marker of frailty and predictor of outcomes in older adults undergoing cardiovascular intervention. The objective of this study was to delineate the prevalence of slow GS, evaluate the association of GS with factors used in standard cardiovascular assessments, and evaluate the association of GS with dependence in activities of daily living (ADLs) in older adults with AS.

HYPOTHESIS

We hypothesized that gait speed would not be associated with clinical factors, but would be associated with ADLs.

METHODS

We evaluated GS, ADLs dependence, and Society of Thoracic Surgery score along with clinical and functional assessments in 102 older adults with AS being evaluated for transcatheter valve. Gait speed <0.5 m/s was considered slow, and GS ≥0.5 m/s was considered preserved. We assessed the association of covariates with GS as well as with ADLs dependence.

RESULTS

Median GS was 0.37 m/s (interquartile range, 0.0-0.65 m/s). Sixty-four (63%) subjects had slow GS. Of commonly employed clinical covariates, only prior coronary intervention and serum albumin were weakly associated with GS. However, GS was independently associated with ADLs dependence (Odds ratio: 1.52 [1.21-1.91] for every 0.1 m/s decrease in GS; P = 0.0003).

CONCLUSIONS

Although the prevalence of slow GS in a population of elderly patients with severe AS being screened for transcatheter valve was high, there were only weak associations between GS and other risk stratifying tools. The strong association between GS and dependent functional status suggests that assessment of gait speed is a useful, objectively measurable, risk stratification tool in this population.