Atherosclerosis of the ascending aorta is a predictor of renal dysfunction after cardiac operations

Predictive nomogram for 28-day mortality risk in mitral valve disorder patients in the intensive care unit: A comprehensive assessment from the MIMIC-III database

BACKGROUND

Mitral valve disorder (MVD) stands as the most prevalent valvular heart disease. Presently, a comprehensive clinical index to predict mortality in MVD remains elusive. The aim of our study is to construct and assess a nomogram for predicting the 28-day mortality risk of MVD patients.

METHODS

Patients diagnosed with MVD were identified via ICD-9 code from the MIMIC-III database. Independent risk factors were identified utilizing the LASSO method and multivariate logistic regression to construct a nomogram model aimed at predicting the 28-day mortality risk. The nomogram's performance was assessed through various metrics including the area under the curve (AUC), calibration curves, Hosmer-Lemeshow test, integrated discriminant improvement (IDI), net reclassification improvement (NRI), and decision curve analysis (DCA).

RESULTS

The study encompassed a total of 2771 patients diagnosed with MVD. Logistic regression analysis identified several independent risk factors: age, anion gap, creatinine, glucose, blood urea nitrogen level (BUN), urine output, systolic blood pressure (SBP), respiratory rate, saturation of peripheral oxygen (SpO2), Glasgow Coma Scale score (GCS), and metastatic cancer. These factors were found to independently influence the 28-day mortality risk among patients with MVD. The calibration curve demonstrated adequate calibration of the nomogram. Furthermore, the nomogram exhibited favorable discrimination in both the training and validation cohorts. The calculations of IDI, NRI, and DCA analyses demonstrate that the nomogram model provides a greater net benefit compared to the Simplified Acute Physiology Score II (SAPSII), Acute Physiology Score III (APSIII), and Sequential Organ Failure Assessment (SOFA) scoring systems.

CONCLUSION

This study successfully identified independent risk factors for 28-day mortality in patients with MVD. Additionally, a nomogram model was developed to predict mortality, offering potential assistance in enhancing the prognosis for MVD patients. It's helpful in persuading patients to receive early interventional catheterization treatment, for example, transcatheter mitral valve replacement (TMVR), transcatheter mitral valve implantation (TMVI).

The Rationalisation of Intra-Operative Imaging During Cardiac Surgery: A Systematic Review

INTRODUCTION

One critical complication of cardiac surgery is cerebrovascular accidents (CVAs). Ascending aorta atherosclerosis poses a significant risk of embolisation to distal vessels and to cerebral arteries. Epi-aortic ultrasonography (EUS) is thought to offer a safe, high-quality accurate visualisation of the diseased aorta to guide the surgeon on the best surgical approach to the planned procedure and potentially improve neurological outcomes post-cardiac surgery.

METHOD

The authors conducted a comprehensive search of PubMed, Scopus and Embase. Studies that reported on epi-aortic ultrasound use in cardiac surgery were included. Major exclusion criteria were: (1) abstracts, conference presentations, editorials, literature reviews; (2) case series with <5 participants; (3) epi-aortic ultrasound in trauma or other surgeries.

RESULTS

A total of 59 studies and 48,255 patients were included in this review. Out of the studies that reported patient co-morbidities prior to cardiac surgery, 31.6% had diabetes, 59.5% had hyperlipidaemia and 66.1% had a diagnosis of hypertension. Of those that reported significant ascending aorta atherosclerosis found on EUS, this ranged from 8.3% of patients to 95.2% with a mean percentage of 37.8%. Hospital mortality ranged from 7% to 13%; four studies reported zero deaths. Long-term mortality and stroke rate varied significantly with hospital duration.

CONCLUSION

Current data have shown EUS to have superiority over manual palpation and transoesophageal echocardiography in the prevention of CVAs following cardiac surgery. Yet, EUS has not been implemented as a routine standard of care. Extensive adoption of EUS in clinical practice is warranted to aid large, randomised trials before making prospective conclusions on the efficacy of this screening method.

A Simple Clinical Risk Score to Predict Post-Discharge Mortality in Chinese Patients Hospitalized with Heart Failure

BACKGROUND

Cardiovascular diseases are the leading causes of death in China. However, present efforts to identify the risk factors for death in patients hospitalized with heart failure (HF) are primarily focused on in-hospital mortality and 30-day mortality in the United States. Thus, a model similar to the model used for predicting the risk in patients considered for cardiovascular surgical procedures is needed to evaluate the risk of the patients admitted with a diagnosis of HF.

OBJECTIVE

To identify variables that can predict post-discharge one-year HF mortality and develop a risk score to assess the risk of dying within one year.

METHODS

In the present study, 1,742 Chinese patients with HF were randomly divided into two groups: a derivation sample group and a test sample group. A Markov Chain Monte Carlo simulation method was used to identify variables that can predict the one-year post-discharge mortality. Variables with a frequency of >1% in the bivariate analysis and that were considered clinically meaningful were eligible for further modeling analyses. The posterior probability that a variable was statistically and significantly associated with the outcome was calculated as the total number of times that the variable's 95% CI did not overlap with 1 (i.e., the reference point) divided by the total number of iterations. A variable with a probability of 0.9 or higher was considered a robust risk factor for predicting the outcome, and this was included in the final variable list. The level of statistical significance adopted was 5%.

RESULTS

Five variables that could robustly predict the one-year post-discharge mortality were identified: age, female gender, New York Heart Association functional classification score >3, left atrial diameter, and body mass index. Both derivation and test models had a receiver operating curve area of 0.79. These selected variables were used to assess the one-year HF mortality risk score, and these were divided into three groups (low, moderate, and high). The high-risk group corresponds to nearly 86% of the deaths, while the moderate group corresponds to 12% of the deaths.

CONCLUSION

A simple 5-variable risk score can be used to assess the one-year post-discharge mortality of hospitalized Chinese patients with HF.

Cholesterol Embolization Syndrome After Carotid Artery Stenting Associated with Delayed Cerebral Hyperperfusion Intracerebral Hemorrhage

BACKGROUND

The cholesterol embolization syndrome (CES) results from the distal embolization of cholesterol crystals from atheromatous plaques in large vessels such as the aorta and results in multiorgan damage.

CASE DESCRIPTION

We present the case of a patient with definite CES with skin manifestations (e.g., blue toes) and renal and neurological dysfunction, including parenchymal hematoma with cytotoxic and vasogenic edema after he had undergone left carotid artery stenting for symptomatic critical left carotid artery stenosis.

CONCLUSIONS

Our patient with CES had cutaneous involvement affecting the lower limbs and renal and neurological involvement. High clinical suspicion and early treatment can reduce the mortality and morbidity after endovascular procedures. The neurological symptoms had most likely resulted from delayed cerebral hyperperfusion syndrome resulting in intracerebral hemorrhage.

Impact of Aortic Atherosclerosis Burden on Outcomes of Surgical Aortic Valve Replacement

BACKGROUND

Epiaortic ultrasound detects and localizes ascending aortic atherosclerosis. In this analysis we investigated the association between epiaortic ultrasound-based atheroma grade during surgical aortic valve replacement (SAVR) and perioperative adverse outcomes.

METHODS

SAVR patients in a randomized trial of 2 embolic protection devices underwent a protocol-defined 5-view epiaortic ultrasound read at a core laboratory. Aortic atherosclerosis was quantified with the Katz atheroma grade, and patients were categorized as mild (grade I-II) or moderate/severe (grade III-V). Multivariable logistic regression was used to estimate associations between atheroma grade and adverse outcomes, including death, clinically apparent stroke, cerebral infarction on diffusion-weighted magnetic resonance imaging, delirium, and acute kidney injury (AKI) by 7 and 30 days.

RESULTS

Precannulation epiaortic ultrasound data were available for 326 of 383 randomized patients (85.1%). Of these, 106 (32.5%) had moderate/severe Katz atheroma grade at any segment of the ascending aorta. Although differences in the composite of death, stroke, or cerebral infarction on diffusion-weighted magnetic resonance imaging by 7 days were not statistically significant, moderate/severe atheroma grade was associated with a greater risk of AKI by 7 days (adjusted odds ratio, 2.63; 95% confidence interval, 1.24-5.58; P = .01). At 30 days, patients with moderate/severe atheroma grade had a greater risk of death, stroke, or AKI (adjusted odds ratio, 1.97; 95% confidence interval, 1.04-3.71; P = .04).

CONCLUSIONS

Moderate/severe aortic atherosclerosis was associated with an increased risk of adverse events after SAVR. Epiaortic ultrasound may serve as a useful adjunct for identifying patients who may benefit from strategies to reduce atheroembolic complications during SAVR.

Prevention of Cardiac Surgery-Associated Acute Kidney Injury

Numerous strategies have been evaluated to prevent early CSA-AKI. Although correction of hemodynamic problems is paramount, there are no clinical studies that compare different hemodynamic management or monitoring strategies with regard to their effect on kidney function. Pharmacologic strategies including diuretics, different classes of vasodilators and drugs with anti-inflammatory effects such as N-acetyl-cysteine, do not appear to be effective. Most of the studies are underpowered and use physiological rather than clinical endpoints. Further trials are warranted with fenoldopam and nesiritide (rhBNP). Observational and underpowered randomized studies show beneficial renal effects of off-pump technique and avoidance of aortic manipulation. There is very limited evidence for preoperative fluid loading and preemptive RRT. Potentially nephrotoxic agents should be used with caution in patients at risk of CSA-AKI. Tranexamic acid or aminocaproic acid should be preferred over aprotinin. No pharmacologic intervention has been adequately tested in the prevention of late CSA-AKI. A single-center study, including a predominance of patients after cardiac surgery, showed a decrease of kidney injury with tight glycemic control.

Aortic Atheroma Increases the Risk of Long-Term Mortality in 20,000 Patients

BACKGROUND

The association between long-term survival and aortic atheroma in cardiac surgical patients has not been comprehensively investigated. In this study we determine the relation between grade of atheroma and the risk of long-term mortality in a retrospective cohort of more than 20,000 patients undergoing cardiac operation during a 20-year period.

METHODS

We included 22,304 consecutive intraoperative transesophageal and epiaortic ultrasound examinations performed at Brigham and Women's Hospital between 1995 and 2014, with long-term follow-up. The extent of atheromatous disease recorded in each examination was used for analysis. Mortality data were obtained from our institution's data registry. Mortality analyses were done using Cox proportional hazard regression models with follow-up as a time scale. We repeated the analysis in a subgroup of 14,728 patients with more detailed demographic characteristics, including postoperative stroke, queried from the institutional Society of Thoracic Surgeons database.

RESULTS

A total of 7,722 mortality events and 872 stroke events occurred. Patients with atheromatous disease demonstrated a significant increase in mortality across all grades of severity, both for the ascending and descending aorta. This relation remained unchanged after adjusting for additional covariates. Adjustments for postoperative stroke resulted in only minimal attenuation in the risk of postoperative mortality related to aortic atheroma.

CONCLUSIONS

Aortic atheromatous disease of any grade in the ascending and descending aorta is a significant long-term risk of long-term, all-cause mortality in cardiac operation patients. This association remains independent of other conventional risk factors and is not related to postoperative cerebrovascular accidents.

The Genetic Determinants of Renal Impairment Following Cardiac Surgery

Cardiac surgery is frequently performed, and acute renal dysfunction is a common adverse event following this procedure. Cardiac surgery-related renal injury independently predicts longer hospital stays and greater rates of morbidity and mortality. Although much work has been completed toward better understanding of this phenomenon, the state of knowledge concerning surgery-related renal injury remains limited. Currently, there is no effective paradigm to identify patients who are at risk for this condition; the specific mechanisms of renal injury during surgery are incompletely understood; and few therapies exist to prevent or treat this phenomenon. To better understand this common clinical problem, recent research has focused on the importance of genetic variability within the physiological and patho-physiological systems that underlie renal dysfunction following cardiac surgery. Emphasizing the importance of using genetics to elucidate molecular mechanisms of this disease, this article reviews the current literature on genetic polymorphisms and post cardiac surgery-related renal dysfunction.

3-D Imaging for Aortic Plaque Assessment

Stroke and neurologic dysfunction continue to complicate cardiac surgery despite improvements in cardiopulmonary bypass. Intra-aortic plaque disrupted during aortic manipulation is a known risk factor contributing to neurologic complications; therefore, avoidance of these plaques during aortic manipulation is important. Intraoperative epiaortic echocardiography, with its high sensitivity and specificity, has become the modality of choice for detecting plaque within the aorta during cardiac surgery and is superior to either transesophageal echocardiography or aortic palpation for this purpose. Recently the matrix x4 three-dimensional (3D) ultrasound probe (Philps Medical Systems) was introduced allowing both real time 3D imaging and electrocardiography-gated “full volume” imaging, which essentially acquires a larger image but requires 8 cardiac cycles. Modification of our routine scanning technique was required, employing a saline (about 30 mL) filled sterile sheath secured with a sterile elastic band (creating a saline pocket). There appears little difference in the sensitivity of either 2D or 3D imaging to detect plaque within the aorta. We found that live 3D was superior to 2D imaging in identifying, localizing, and defining the true extent of plaque in the aorta.

Imaging Techniques for Diagnosis of Thoracic Aortic Atherosclerosis

The most severe complications after cardiac surgery are neurological complications including stroke which is often caused by emboli merging from atherosclerosis in the ascending aorta to the brain. Information about the thoracic aorta is crucial in reducing the embolization risk for both surgical open and closed chest procedures such as transaortic heart valve implantation. Several techniques are available to screen the ascending aorta, for example, transesophageal echocardiography (TEE), epiaortic ultrasound, TEE A-view method, manual palpation, computed tomography, and magnetic resonance imaging. This paper provides a description of the advantages and disadvantages of these imaging techniques.

Risk factors of atheromatous aorta in cardiovascular surgery

Objective

To determine the prevalence and profile of ascending aorta or aortic arch atheromatous disease in cardiovascular surgery patients, its risk factors and its prognostic implication early after surgery.

Methods

Between January 2007 and June 2011, 2042 consecutive adult patients were analyzed, with no exclusion criteria. Atheromatous aorta diagnosis was determined intraoperatively by surgeon palpation of the aorta. Determinants of atheromatous aorta, as well as its prognostic implication were studied by multivariate logistic regression.

Results

Prevalence of atheromatous aorta was 3.3% (68 patients). Determinants were age > 61 years (OR= 2.79; CI95%= 2.43 - 3.15; P<0.0001), coronary artery disease (OR=3.1; CI95%=2.8 - 3.44; P=0.002), hypertension (OR=2.26; CI95%=1.82 - 2.7; P=0.03) and peripheral vascular disease (OR=3.15; CI95%= 2.83 - 3.46; P=0.04). Atheromatous aorta was an independent predictor of postoperative cerebrovascular accident (OR=3.46; CI95%=3.18 - 3.76; P=0.01).

Conclusion

Although infrequent, the presence of atheromatous aorta is associated with advanced age, hypertension, coronary artery disease and peripheral vascular disease. In those patients, a more detailed preoperative and intraoperative assessment of the aorta is justified, due to greater risk of postoperative cerebrovascular accident.

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.

Coronary artery bypass grafting: Part 2--optimizing outcomes and future prospects

Since first introduced in the mid-1960s, coronary artery bypass grafting (CABG) has become the standard of care for patients with coronary artery disease. Surprisingly, the fundamental surgical technique itself did not change much over time. Nevertheless, outcomes after CABG have dramatically improved over the first 50 years. Randomized trials comparing percutaneous coronary intervention (PCI) to CABG have shown converging outcomes for select patient populations, providing more evidence for wider use of PCI. It is increasingly important to focus on the optimization of the short- and long-term outcomes of CABG and to reduce the level of invasiveness of this procedure. This review provides an overview on how new techniques and widespread consideration of evolving strategies have the potential to optimize outcomes after CABG. Such developments include off-pump CABG, clampless/anaortic CABG, minimally invasive CABG with or without extending to hybrid procedures, arterial revascularization, endoscopic vein harvesting, intraprocedural epiaortic scanning, graft flow assessment, and improved secondary prevention measures. In addition, this review represents a framework for future studies by summarizing the areas that need more rigorous clinical (randomized) evaluation.

Bad aorta

As its outcomes improve, cardiac surgery has been performed on more and more cases which were previously considered to be difficult to deal with. However, there are still a number of problems to be solved regarding surgery on patients with severe sclerotic lesions in the ascending aorta, which we collectively call "bad aorta". Concerning a preoperative assessment of the ascending aorta, our report revealed no relationship between the severity of calcification detected with a preoperative non-enhanced CT and the aortic lesion found during the surgery. Meanwhile, an intraoperative epiaortic ultrasound enables us to make high-quality evaluations of the aorta without imposing much burden on the patient. This modality may be essential for cardiac surgery. As for surgical management for bad aorta, quite a few methods have been reported to this point, but the overall operative mortality rate and cerebrovascular accident rate are relatively high, at a little <10 %, respectively. With the recent cross-clamping method under short-term total circulatory arrest (TCA), however, the results are much better; these rates total around 5 %. Further improvement is expected in the outcome of cardiac surgery on bad aorta cases by establishing a modality to evaluate sclerotic lesions in the ascending aorta with epiaortic ultrasound and by selecting a proper procedure for each case.

The association between atherosclerotic renal artery stenosis and acute kidney injury in patients undergoing cardiac surgery

BACKGROUND

Atherosclerotic renal artery stenosis (ARAS) and coronary artery disease (CAD) commonly co-exist. Some patients with unidentified ARAS may undergo cardiac surgery. While acute kidney injury (AKI) is a frequent and serious complication of cardiac surgery, we aim to evaluate the influence of ARAS on the occurrence of postoperative AKI in patients with normal or near-normal baseline renal function following cardiac surgery.

METHODS

A total of 212 consecutive patients undergoing aortography after coronary angiography and cardiac surgery were retrospectively studied for their preoperative and intraoperative conditions. AKI was defined as an absolute increase in serum creatinine of more than or equal to 0.3 mg/dl (≥26.4 µmol/l) or a percentage increase in creatinine of more than or equal to 50% (1.5-fold from baseline) after cardiac surgery. A propensity score-adjusted logistic regression models was used in estimating the effect of ARAS on the risk of postoperative AKI.

RESULTS

ARAS (≥50%) was observed in 50 (23.6%) patients, and 83 (39.2%) developed AKI after cardiac surgery. A correlation existed between renal artery patency and preoperative-to-postoperative %ΔCr in patients with ARAS (r = 0.297, P<0.0001). The propensity score-adjusted regression model showed the occurrence of postoperative AKI in patients with ARAS was significantly higher than those without ARAS (OR 2.858, 95% CI 1.260-6.480, P = 0.011).

CONCLUSION

ARAS is associated with postoperative AKI in patients with normal or near-normal baseline renal function after cardiac surgery.

Interactions between cardiovascular and cerebrovascular disease

OPININION STATEMENT: All patients with ischemic stroke should undergo a comprehensive assessment of cardiovascular risk. Patients with carotid artery disease, symptoms of cerebral ischemia and high cardiovascular risk profiles should be considered for noninvasive testing for coronary artery disease (CAD). Routine testing for CAD before carotid endarterctomy is not recommended. Patients with coexisting coronary and carotid artery disease should be more aggressively treated for reducing their "very high" risk of cardiovascular events. In patients candidates to carotid revascularization, a preoperative coronary angiography and coronary revascularization are not recommended. Warfarin is recommended in all patients with moderate to high risk of stroke. Novel oral anticoagulants represent an attractive alternative to warfarin. However, their place in therapy in clinical practice is not yet established. Percutaneous closure of the left atrial appendage for stroke prophylaxis may be considered in selected patients with atrial fibrillation and contraindications for oral anticoagulant therapy. Warfarin is not indicated in patients with heart failure who are in sinus rhythm. Percutaneous closure of patent foramen does not seem to be superior to medical therapy for the prevention of recurrences in patients with cryptogenic stroke.

Descending aortic calcification increases renal dysfunction and in-hospital mortality in cardiac surgery patients with intraaortic balloon pump counterpulsation placed perioperatively: a case control study

Introduction

Acute kidney injury (AKI) after cardiac surgery increases length of hospital stay and in-hospital mortality. A significant number of patients undergoing cardiac surgical procedures require perioperative intra-aortic balloon pump (IABP) support. Use of an IABP has been linked to an increased incidence of perioperative renal dysfunction and death. This might be due to dislodgement of atherosclerotic material in the descending thoracic aorta (DTA). Therefore, we retrospectively studied the correlation between DTA atheroma, AKI and in-hospital mortality.

Methods

A total of 454 patients were retrospectively matched to one of four groups: -IABP/-DTA atheroma, +IABP/-DTA atheroma, -IABP/+DTA atheroma, +IABP/+DTA atheroma. Patients were then matched according to presence/absence of DTA atheroma, presence/absence of IABP, performed surgical procedure, age, gender and left ventricular ejection fraction (LVEF). DTA atheroma was assessed through standard transesophageal echocardiography (TEE) imaging studies of the descending thoracic aorta.

Results

Basic patient characteristics, except for age and gender, did not differ between groups. Perioperative AKI in patients with -DTA atheroma/+IABP was 5.1% versus 1.7% in patients with -DTA atheroma/-IABP. In patients with +DTA atheroma/+IABP the incidence of AKI was 12.6% versus 5.1% in patients with +DTA atheroma/-IABP. In-hospital mortality in patients with +DTA atheroma/-IABP was 3.4% versus 8.4% with +DTA atheroma/+IABP. In patients with +DTA atheroma/+IABP in hospital mortality was 20.2% versus 6.4% with +DTA atheroma/-IABP. Multivariate logistic regression identified DTA atheroma > 1 mm (P = *0.002, odds ratio (OR) = 4.13, confidence interval (CI) = 1.66 to 10.30), as well as IABP support (P = *0.015, OR = 3.04, CI = 1.24 to 7.45) as independent predictors of perioperative AKI and increased in-hospital mortality. DTA atheroma in conjunction with IABP significantly increased the risk of developing acute kidney injury (P = 0.0016) and in-hospital mortality (P = 0.0001) when compared to control subjects without IABP and without DTA atheroma.

Conclusions

Perioperative IABP and DTA atheroma are independent predictors of perioperative AKI and in-hospital mortality. Whether adding an IABP in patients with severe DTA calcification increases their risk of developing AKI and mortality postoperatively cannot be clearly answered in this study. Nevertheless, when IABP and DTA are combined, patients are more likely to develop AKI and to die postoperatively in comparison to patients without IABP and DTA atheroma.

Renal injury is associated with operative mortality after cardiac surgery for women and men

OBJECTIVES

The purpose of this study was to determine whether acute renal injury develops more frequently in women than in men after cardiac surgery and whether this complication is associated with operative mortality in women.

METHODS

Prospectively collected data were evaluated from 9461 patients undergoing coronary artery bypass graft surgery, cardiac valve surgery, or both (3080 women) and not receiving preoperative dialysis. The glomerular filtration rate was estimated by using the Modification of Diet in Renal Disease equations with the last plasma creatinine level before surgical intervention (baseline) and the highest level of the first postoperative week. The primary renal injury outcome was the composite end point of renal injury according to RIFLE criteria (estimated glomerular filtration rate decrease >50% from baseline value) or failure.

RESULTS

Thirty-day operative mortality and renal injury were more common in women than in men (5.9% vs 2.8%, P = .01; 5.1% vs 3.6%, P < .001, respectively). Nonetheless, patient sex was not independently associated with risk for renal injury when the baseline estimated glomerular filtration rate was included in multivariate modeling. Perioperative complications, intensive care unit length of stay, and mortality were more frequent for patients with than without renal injury (women, 20.6% vs 3.2%, P < .0001; men, 18.3% vs 2.2%, P < .001). Renal injury was independently associated with 30-day mortality for women (odds ratio, 3.96; 95% confidence interval, 1.86-8.44; P < .0001) and men (odds ratio, 4.05; 95% confidence interval, 2.19-7.48; P < .0001).

CONCLUSIONS

Postoperative renal injury is independently associated with 30-day mortality regardless of patient sex. Higher rates of renal injury in women compared with men might be explained in part by a higher prevalence of low estimated glomerular filtration rate before surgical intervention.

Preoperative statin therapy is not associated with a reduced incidence of postoperative acute kidney injury after cardiac surgery

BACKGROUND

Our objective was to examine the association between preoperative statin therapy and the prevalence of postoperative acute kidney injury (AKI) in patients undergoing cardiac surgery with the use of cardiopulmonary bypass.

METHODS

We performed a retrospective investigation of 10,648 consecutive patients undergoing coronary artery bypass grafting using cardiopulmonary bypass and/or valve surgery between January 2002 and December 2006. Patients were divided into 2 groups depending on preoperative therapy with statin drugs. The primary outcome was postoperative AKI based on the RIFLE (Risk, Injury, Failure, Loss, End-stage) criteria. Secondary outcomes included requirement for postoperative dialysis and hospital mortality. Multivariable logistic regression models were developed for the primary and secondary outcomes. To control for selection bias related to statin therapy, a propensity score was developed using a greedy matching technique.

RESULTS

The incidence of AKI was 12.1% (n = 1286). AKI occurred in 13.31% of patients receiving preoperative statins (819 of 6152 patients) versus 10.41% in the no statin group (467 of 4487 patients) (P < 0.001). The incidence of postoperative dialysis was 1.71% (n = 182). Postoperative dialysis was needed in 1.75% of patients in the statin group (108 of 6157 patients) compared with 1.65% of patients (74 of 4491 patients) in the no statin group (P = 0.68). Hospital mortality after surgery occurred in 1.71% (n = 182) of patients. The incidence of mortality for patients in the statin group was 1.71% (105 of 6157 patients) and this was not different from mortality in the no statin group of 1.71% (77 of 4491 patients) (P = 0.97). In multivariate logistic regression analysis, statin therapy was not associated with AKI (odds ratio [OR] 0.97, 95% confidence interval [CI] 0.84-1.12; P = 0.68), postoperative dialysis (OR 0.80, 95% CI 0.55-118; P = 0.23), or hospital mortality (OR 0.803, 95% CI 0.56-1.16; P = 0.24). In 2646 propensity-matched pairs, the incidence of AKI was 12.0% in the statin group versus 12.8% in the no statin group (P = 0.38). The statin group had a 1.63% incidence of postoperative dialysis versus 2.08% in the no statin group (P = 0.22). In the same propensity-matched population, hospital mortality occurred in 1.63% of patients in the statin group compared with 2.1% in the no statin group (P = 0.19).

CONCLUSION

These results suggest that previously reported reductions in perioperative mortality for patients taking preoperative statins and undergoing cardiac surgery is likely not mediated through a reduction in postoperative AKI.

Intra–aortic Filtration in Cardiac Surgery

Cardiac surgery is associated with a significant risk of adverse outcomes, particularly neurologic and renal. Embolic events are the primary source of these deleterious consequences. Intraaortic filtration is the only current technology shown to effectively capture particulates released during cardiac procedures and decrease morbidity and mortality. Although most surgical candidates may potentially benefit from intraaortic filtration, some patients are more likely to experience improved outcomes. Based on the evidence reported in the literature and the extensive experience of the authors, the following opinion details the authors’ rationale and recommendations for patient selection for intraaortic filtration during cardiac surgery.

Reducing emboli in cardiac surgery: does it make a difference?

Particulate embolization remains a serious complication of cardiac surgery. Adverse events associated with particulate embolization affect patient morbidity and long-term survival, and increase the length of hospital stay and the cost of health care. Today, atherosclerosis plays a role in at least two-thirds of all adverse events after coronary artery revascularization, and postoperative stroke is the second most common cause of operative mortality. Because many lower-risk patients now undergo interventional revascularization, higher-risk patients are now typically referred for surgical revascularization. These patients are older and sicker, and have multiple comorbidities, making them more susceptible to adverse events. For these high-risk patients, surgeons should be proactive in attempting to reduce the possibility of emboli. Patients must be carefully assessed before surgery to determine their risk, and if the risk is high, surgeons should consider using newer, innovative devices, and techniques in their operative strategy that have proven to be effective in mitigating some of the potential embolic adverse events. A multifaceted, preventive strategy can make a difference, not only in reducing particulate emboli, but also in reducing morbidity and in lowering the economic burden on the health-care system. This brief review will address three areas of focus that are important for the prevention of particulate embolization: (i) prevalence and morbidity of atherosclerotic disease; (ii) risk factors for adverse neurologic events; and (iii) prevention/mitigation of adverse events for patients undergoing cardiac surgery.

Acute kidney injury and chronic kidney disease after cardiac surgery

Kidney dysfunction is common after cardiac surgery and predicts mortality risk and poorer long-term outcome, particularly when acute injury superimposes upon chronic kidney disease. Numerous insults contribute to perioperative renal impairment including major surgical trespass, procedure-specific interventions (eg, deep hypothermic circulatory arrest), and postoperative complications. Regardless of cause, evidence supports a role for renal impairment and accumulation of "uremic toxins" as direct contributors to adverse outcome. No one has yet characterized a loss of renal function small enough to be insignificant. Despite considerable research focus, progress in development of interventions aimed at perioperative renoprotection has been disappointing. However, practice modifications can influence the likelihood of acute kidney injury, and several recent advances provide hope for the future. We review pathophysiologic understanding of this disorder; evaluate the confusing relationship (causal v epiphenomena) among acute kidney injury, chronic kidney disease, and adverse outcome after cardiac surgery; and provide an evidence-based assessment of the conduct of cardiac surgery and renoprotection strategies.

Risk index for perioperative renal dysfunction/failure: critical dependence on pulse pressure hypertension

BACKGROUND

An acute renal event after coronary bypass graft surgery is associated with high mortality and substantial additive cost.

METHODS AND RESULTS

This prospective and descriptive study of 4801 patients having coronary bypass graft surgery with cardiopulmonary bypass from November 1996 to June 2000 at 70 centers in 16 countries established associations between predictor variables and postoperative renal composite (renal dysfunction and/or renal failure) from a cohort of 2381 patients and developed a risk index assessed in a validation cohort of 2420 patients. Postoperative renal composite occurred in 231 patients (4.8%). Independent and significant risk factors were age >75 years (odds ratio [OR], 2.04; 95% confidence interval [CI], 1.23 to 3.37; P=0.006), preoperative congestive heart failure (OR, 2.38; CI, 1.55 to 3.64; P<0.001), prior myocardial infarction (OR, 1.75; CI, 1.08 to 2.83; P=0.023), preexisting renal disease (OR, 3.71; CI, 2.41 to 5.70; P<0.001), intraoperative multiple inotrope use (OR, 2.75; CI, 1.75 to 4.31; P<0.001), intraoperative intra-aortic balloon pump insertion (OR, 4.41; CI, 2.21 to 8.80; P<0.001), cardiopulmonary bypass >2 hours (OR, 1.78; CI, 1.15 to 2.74; P=0.01), and preoperative pulse pressure such that for every additional 20-mm Hg increment in pulse pressure >40 mm Hg, there was an OR of 1.49 (CI, 1.17 to 1.89; P=0.001). Patients with pulse pressure hypertension >80 mm Hg were 3 times more likely to die a renal-related death compared with those without (3.7% versus 1.1%).

CONCLUSIONS

Beside established risk factors, pulse pressure is independently and significantly associated with increased renal composite.

Aortic assessment for cardiac surgical procedures

Aortic atheromatous disease is associated with stroke in both the ambulatory and perioperative setting. In addition to atheromatous deposits, a reduction in the compliance of the aorta takes place as elastin fibers are replaced by collagen fibers. Both of these distinct processes, termed atherosclerosis, can easily be measured using transesophageal echocardiography during cardiac surgery. A review of the literature demonstrates many studies supporting the benefit of transesophageal echocardiography examination of the aorta for reducing stroke following cardiac surgery, through modification of surgical techniques. There have also been attempts by surgeons to remove atheromatous lesions from the aorta during cardiac surgery. Unfortunately, these procedures currently have a high perioperative mortality. Finally, medical therapy such as warfarin or statins may help reduce the incidence of stroke following heart surgery.

The degree of atherosclerosis in the descending aorta does not predict poor in-hospital outcome after surgery requiring cardiopulmonary bypass

OBJECTIVE

This study examined if the degree of atherosclerosis in the descending aorta is an independent predictor of poor in-hospital outcome for patients presenting for surgery involving cardiopulmonary bypass.

DESIGN

The degree of atherosclerosis of the descending aorta was retrospectively reviewed in patients presenting for surgical procedures involving cardiopulmonary bypass from January 1, 2000, to December 31, 2003. Preoperative risk factors and in-hospital postoperative outcome parameters were obtained.

SETTING

University teaching hospital.

PARTICIPANTS

There were 310 consecutive patients enrolled in the study.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two hundred forty-seven patients had coronary artery bypass grafting with or without valvular surgery, and 63 patients had isolated valvular surgery. The degree of atherosclerosis was rated as normal in 86 (28%), mild in 106 (34%), moderate in 69 (22%), and severe in 49 (16%) patients. Adjusting only for the degree of atherosclerosis, the total intensive care unit (ICU) time and the number of deaths were significantly higher in those patients with severe disease. Multivariable models adjusting for patients' risk factors showed a significant influence of atherosclerosis on total ICU time but not on other outcomes. The strongest predictor of poor outcome was a history of previous stroke (cerebral vascular accident). Other significant factors predicting poor outcome included previous coronary artery bypass surgery, a history of congestive heart failure, a history of dialysis, advanced age, and female sex.

CONCLUSIONS

The degree of atherosclerosis in the descending aorta is not an independent predictor of poor in-hospital outcome after surgery involving cardiopulmonary bypass.

Symmetry™ Aortic Connector Devices and Acute Renal Injury: A Comparison of Renal Dysfunction After Three Different Aortocoronary Bypass Surgery Techniques

Although the pathogenesis of acute renal injury after cardiac surgery is multifactorial, atherosclerosis of the ascending aorta and embolic burden are strong independent predictors. Use of the Symmetry aortic connector device (ACD) for proximal anastomosis of coronary grafts may reduce ascending aortic atheroembolism. Therefore, we tested the hypothesis that off-pump coronary artery bypass (OPCAB) surgery performed using an ACD is associated with less postoperative renal dysfunction compared with conventional OPCAB or on-pump coronary artery bypass graft (CABG) surgery. Three-thousand-three-hundred consecutive patients undergoing non-emergent aortocoronary bypass surgery were retrospectively divided into three groups by surgical procedure; Group A: OPCAB with ACD (n = 124), Group B: standard OPCAB (n = 313), Group C: on-pump CABG (n = 2863). Postoperative peak fractional change in creatinine compared with baseline was used as a measure of renal outcome. Multivariable analysis did not identify ACD use as an independent predictor of postoperative peak fractional change in creatinine (P = 0.71), although the relationships of several known renal risk factors with postoperative peak fractional change in creatinine were confirmed. We could not find evidence that OPCAB surgery using ACDs reduces acute renal injury compared with standard OPCAB or CABG surgery.

[Antithrombotic drugs in the prevention of ischemic stroke]

Stroke prevention cannot be dissociated from cardiovascular prevention in general. It is based on the correction of vascular risk factors, particularly hypertension and tobacco smoking, and on antithrombotic drugs which tackle the thrombo-embolic process which is the immediate cause of the ischemic event. Ischemic strokes exhibit considerable etiopathogenic diversity, the underlying cause modifying thrombus composition. In atherothrombotic brain infarction, platelets play a major role and antiplatelet drugs have a benefit/risk ratio better than that of oral anticoagulants, with a 25% reduction in the combined risk of ischemic stroke, myocardial infarction and vascular death. Antiplatelet drugs are also used in small artery diseases of the brain although the role of thrombosis is unknown and no specific trial has been devoted to this variety of cerebrovascular disease. In emboligenic cardiac diseases, atrial fibrillation in particular, stasis of the dilated left atrium favors coagulation phenomena, hence the much better efficacy of oral anticoagulants (presently vitamin K antagonists) both in primary and secondary prevention with a 70% risk reduction in cerebral infarction, compared with only 20% for aspirin. The expected benefit of antithrombotic drugs must be weighed against their inherent hemorrhagic risk, which is greatest for oral anticoagulants, slightly less for association of antiplatelet drugs and even less for each antiplatelet drug given alone. The use of antithrombotic drugs allows a targeted prevention of cerebral infarction. It is based on a triple case by case evaluation: that of the cause and of the risk it carries, that of the benefit expected from antithrombotic drugs, and that of their inherent hemorrhagic risk.

The Incidence of Emboli during Cardiac Surgery: A Histopathologic Analysis of 2297 Patients

OBJECTIVE

Manipulation of the atherosclerotic aorta during cardiac surgery is assumed to cause embolization, which can contribute to adverse outcomes. Recently, as a result of worldwide trials deploying the Embol-X intraaortic filter during cardiac surgery, such emboli were captured and processed for histopathologic analysis.

METHODS

Filters with a pore size of 120 microns were placed in 2297 patients who underwent the following operations: coronary artery bypass grafting (CABG) (70%), valve (17%), combination CABG/valve (11%), and other (2%).

RESULTS

The filters captured at least one embolus in 98% of the patients. An average of 8.3 particles was captured per filter (range of 0-74). The surface area of the emboli was on an average 5.8 mm2 (range of 0-188 mm2). Histologic analysis of the captured particles indicated that in 79% of the filters fibrous atheromata were noted, in 44% there were platelets and fibrin, 8% had red blood cell thrombus, 3% had fibro-fatty/adventitial tissue, 2% had other material including cartilage, myocardium, lung, suture, and a teflon pledget. Of the patients enrolled, 1569 were high-risk. The average number of particles captured in the high-risk patients was 8.5 versus 5.8 for the low- to moderate-risk patients (P < .0001). Concomitantly,there was an increase in the embolic burden between the higher- and lower-risk patients (surface area 6.6 vs. 4.0 mm2, P < .0001).

CONCLUSION

These data show the ubiquitous incidence of emboli during cardiac procedures. Intraaortic filtration should reduce adverse outcomes as was demonstrated for the high-risk patients in this study. Aortic manipulation during cardiac surgery can cause embolization and increase morbidity. The use of an intraaortic filter can decrease the embolic burden. We now report the histopathologic analysis of these emboli.

Preliminary report on the interaction of apolipoprotein E polymorphism with aortic atherosclerosis and acute nephropathy after CABG

BACKGROUND

Renal dysfunction is a serious complication of cardiac surgery that is highly associated with short- and long-term adverse outcome. While the apolipoprotein E (APOE) epsilon4 allele has been linked to the occurrence of both postcardiac surgery acute renal injury (epsilon4 favorable) and ascending aortic arteriosclerosis (epsilon4 unfavorable), the role of epsilon4 in the relationship between these two conditions is unknown. We hypothesized that patients with and without the epsilon4 allele (E4/non-E4) would have different associations between atheroma burden and postoperative renal dysfunction.

METHODS

Ascending, arch, and descending aorta atheromatous burden and APOE status were evaluated for 130 coronary bypass patients. Multivariable analyses were performed for aortic regions to assess the relationship of atheroma burden and APOE epsilon4 status with peak in-hospital postoperative serum creatinine. All p < 0.05 were considered significant.

RESULTS

We found an interaction between E4 status (E4/non-E4; 24/106) and atheroma burden, with a much greater predicted peak in-hospital postoperative serum creatinine for increases in ascending aorta atheroma load for non-E4 patients versus E4 patients (beta coefficient -0.13; p = 0.002). We also confirmed the association between ascending aorta atheroma and peak creatinine (beta coefficient 0.11; p = 0.0008), after controlling for E4 status, preoperative creatinine, and the E4-atheroma interaction.

CONCLUSIONS

Equivalent ascending aortic atheroma burden is associated with a greater susceptibility to postoperative renal injury among patients undergoing cardiac operation who lack the APOE epsilon4 allele. Findings may be attributable to APOE-related differences in inflammation, susceptibility to atheroma detachment (eg, during operative aortic manipulation), or renal vulnerability to embolic injury.

Evidence-based renal protection in cardiac surgery

Acute renal dysfunction is a common serious complication of cardiac surgery. Although a diversity of mechanisms exist by which the kidney can be damaged during cardiac surgery, atheroembolism, ischemia-reperfusion, and inflammation are believed to be primary contributors to perioperative renal insult. In addition, the high metabolic demands of active tubular reabsorption and the oxygen diffusion shunt characteristic of renal circulation make the kidney particularly vulnerable to ischemic injury. Remote effects of acute renal injury likely contribute to the strong association of this condition with other major postoperative morbidities and mortality and justify the search for renoprotective agents, even when dialysis is never required. Nonpharmacologic preventive strategies include procedure planning that is based on risk stratification, avoidance of nephrotoxins, and meticulous perioperative clinical care, including optimizing intravascular volume and attention to modifiable risk factors such as minimizing hemodilution. Although numerous pharmacologic interventions to prevent or treat acute renal injury have shown promise in animal models, randomized placebo-controlled clinical trials that have looked at measures of significant adverse outcomes such as death and dialysis have not confirmed a benefit.

Transcranial Doppler emboli count predicts rise in creatinine after coronary artery bypass graft surgery

OBJECTIVE

To examine the correlation between transcranial Doppler ultrasonography-detected emboli during coronary artery bypass graft surgery with cardiopulmonary bypass and renal dysfunction as determined by the postoperative change in creatinine.

DESIGN

Retrospective review of data from the anesthesia and cardiothoracic surgery databases.

SETTING

Tertiary care university hospital.

PARTICIPANTS

Two hundred eighty-six patients undergoing coronary artery bypass graft surgery.

INTERVENTIONS

Transcranial Doppler ultrasonography of the right middle cerebral artery was performed after induction of general anesthesia through completion of the operation. Doppler signals were recorded and emboli counts determined using an automated counting system.

MEASUREMENTS AND MAIN RESULTS

Renal dysfunction was assessed as the change in creatinine from the preoperative value to the maximum postoperative value (Delta-Cr). There was a significant (p = 0.0003) univariate correlation between postoperative change in creatinine and total number of Doppler-detected emboli. The effect of total number of emboli remained significant (p = 0.0038) in the multivariable analysis after adjustment for covariables (age, sex, number of grafts, left ventricular ejection fraction, hypertension, history of congestive heart failure, diabetes, cardiopulmonary bypass time, preoperative creatinine, and maximum postoperative creatinine).

CONCLUSIONS

Increased numbers of Doppler-detected emboli during coronary artery bypass graft surgery are associated with postoperative renal dysfunction.

Factors Associated With Presence of Ascending Aortic Atherosclerosis in CABG Patients

BACKGROUND

The indication for epiaortic scanning during coronary artery operation is still a matter of debate. Whether this test should be carried out selectively or on a routine basis is unclear. The aim of this study was to determine factors that predict the presence of atherosclerotic ascending aortic wall thickening in patients undergoing coronary artery bypass grafting (CABG).

METHODS

A total of 500 CABG patients underwent epiaortic scanning using a high-frequency linear ultrasonic probe. Maximum ascending aortic wall thickness was measured and correlated with patient-related variables.

RESULTS

Maximum ascending aortic wall thickness significantly correlated with age (p < 0.001), preoperative creatinine level (p = 0.004), European system for cardiac operative risk evaluation (EuroSCORE, p < 0.001), and maximum descending aortic wall thickness (p < 0.001). Body mass index and left ventricular ejection fraction showed no correlation with maximum ascending aortic wall thickness. Of the categorical variables, hypertension (p = 0.02), unstable angina (p = 0.04), chronic obstructive pulmonary disease (p = 0.02), cerebrovascular disease (p < 0.001), and peripheral vascular disease (p < 0.001) were associated with increased ascending aortic wall thickness whereas sex, diabetes, acute cases, and previous cardiac operation were not. Multivariate analysis revealed maximum descending aortic wall thickness (p < 0.001), cerebrovascular disease (p = 0.03), and peripheral vascular disease (p = 0.04) as independent variables significantly associated with maximum ascending aortic wall thickness.

CONCLUSIONS

If epiaortic scanning is not carried out routinely for detection of ascending aortic arteriosclerosis it should at least be performed in patients with old age, hypertension, unstable angina, chronic obstructive pulmonary disease, cerebrovascular disease, peripheral vascular disease, elevated creatinine levels, higher EuroSCOREs, and increased wall thickness of the descending aorta.

The Use of 3D Epiaortic Scanning to Enhance Evaluation of Atherosclerotic Plaque in the Ascending Aorta: A Case Series

Transesophageal echocardiography (TEE) is becoming the standard of practice for cardiopulmonary bypass (CPB) surgery. Unfortunately, large sections of the ascending aorta are not visible on TEE, and epiaortic scanning has proven superior to TEE and aortic palpation in determining the extent of plaque in the ascending aorta. The recently introduced x4 3-dimensional (3D) ultrasound probe allows both real time 3D imaging and gated acquisition sequences. We present a case series in which 3D ultrasound was used for epiaortic imaging in patients undergoing elective cardiac surgery, and we discuss the benefits and limitations of this imaging modality.

Antithrombotic and Thrombolytic Therapy for Ischemic Stroke

This chapter about treatment and prevention of stroke is part of the 7th ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al). Among the key recommendations in this chapter are the following: For patients with acute ischemic stroke (AIS), we recommend administration of i.v. tissue plasminogen activator (tPA), if treatment is initiated within 3 h of clearly defined symptom onset (Grade 1A). For patients with extensive and clearly identifiable hypodensity on CT, we recommend against thrombolytic therapy (Grade 1B). For unselected patients with AIS of > 3 h but < 6 h, we suggest clinicians not use i.v. tPA (Grade 2A). For patients with AIS, we recommend against streptokinase (Grade 1A) and suggest clinicians not use full-dose anticoagulation with i.v. or subcutaneous heparins or heparinoids (Grade 2B). For patients with AIS who are not receiving thrombolysis, we recommend early aspirin therapy, 160 to 325 mg qd (Grade 1A). For AIS patients with restricted mobility, we recommend prophylactic low-dose subcutaneous heparin or low molecular weight heparins or heparinoids (Grade 1A); and for patients who have contraindications to anticoagulants, we recommend use of intermittent pneumatic compression devices or elastic stockings (Grade 1C). In patients with acute intracerebral hematoma, we recommend the initial use of intermittent pneumatic compression (Grade 1C+). In patients with noncardioembolic stroke or transient ischemic attack (TIA) [ie, atherothrombotic, lacunar or cryptogenic], we recommend treatment with an antiplatelet agent (Grade 1A) including aspirin, 50 to 325 mg qd; the combination of aspirin and extended-release dipyridamole, 25 mg/200 mg bid; or clopidogrel, 75 mg qd. In these patients, we suggest use of the combination of aspirin and extended-release dipyridamole, 25/200 mg bid, over aspirin (Grade 2A) and clopidogrel over aspirin (Grade 2B). For patients who are allergic to aspirin, we recommend clopidogrel (Grade 1C+). In patients with atrial fibrillation and a recent stroke or TIA, we recommend long-term oral anticoagulation (target international normalized ratio, 2.5; range, 2.0 to 3.0) [Grade 1A]. In patients with venous sinus thrombosis, we recommend unfractionated heparin (Grade 1B) or low molecular weight heparin (Grade 1B) over no anticoagulant therapy during the acute phase.