Spinal cord injury after thoracic endovascular aortic aneurysm repair

PURPOSE

Thoracic endovascular aortic aneurysm repair (TEVAR) has become a mainstay of therapy for aneurysms and other disorders of the thoracic aorta. The purpose of this narrative review article is to summarize the current literature on the risk factors for and pathophysiology of spinal cord injury (SCI) following TEVAR, and to discuss various intraoperative monitoring and treatment strategies.

SOURCE

The articles considered in this review were identified through PubMed using the following search terms: thoracic aortic aneurysm, TEVAR, paralysis+TEVAR, risk factors+TEVAR, spinal cord ischemia+TEVAR, neuromonitoring+thoracic aortic aneurysm, spinal drain, cerebrospinal fluid drainage, treatment of spinal cord ischemia.

PRINCIPAL FINDINGS

Spinal cord injury continues to be a challenging complication after TEVAR. Its incidence after TEVAR is not significantly reduced when compared with open thoracoabdominal aortic aneurysm repair. Nevertheless, compared with open procedures, delayed paralysis/paresis is the predominant presentation of SCI after TEVAR. The pathophysiology of SCI is complex and not fully understood, though the evolving concept of the importance of the spinal cord's collateral blood supply network and its imbalance after TEVAR is emerging as a leading factor in the development of SCI. Cerebrospinal fluid drainage, optimal blood pressure management, and newer surgical techniques are important components of the most up-to-date strategies for spinal cord protection.

CONCLUSION

Further experimental and clinical research is needed to aid in the discovery of novel neuroprotective strategies for the protection and treatment of SCI following TEVAR.

Anesthetic Management of Laser Lead Extraction for Cardiovascular Implantable Electronic Devices

Cardiovascular implantable electronic devices (CIEDs) play a significant role in the modern management of cardiovascular disease. CIEDs include implantable pacemakers (PMs), implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy (CRT) devices. These devices improve the quality of life of their recipients and help reduce the incidence of sudden cardiac death. Traditionally, CIEDs have been reliant on the use of transvenous endocardial leads to directly connect with the heart. Over time, these endovascular leads may become endothelialized rendering removal extremely difficult. As the indications for CIEDs expands and with the continuing evolution of these devices, the number of patients requiring explantation for device recall, malfunction, and infection continues to increase. In this manuscript, we review the most common CIEDs, the indications and process of lead removal/device explantation, potential complications associated with the procedure and the anesthetic management of these patients.

A Genome-Wide Association Study to Identify Single-Nucleotide Polymorphisms for Acute Kidney Injury

RATIONALE

Acute kidney injury is a common and severe complication of critical illness and cardiac surgery. Despite significant attempts at developing treatments, therapeutic advances to attenuate acute kidney injury and expedite recovery have largely failed.

OBJECTIVES

Identifying genetic loci associated with increased risk of acute kidney injury may reveal novel pathways for therapeutic development.

METHODS

We conducted an exploratory genome-wide association study to identify single-nucleotide polymorphisms associated with genetic susceptibility to in-hospital acute kidney injury.

MEASUREMENTS AND MAIN RESULTS

We genotyped 609,508 single-nucleotide polymorphisms and performed genotype imputation in 760 acute kidney injury cases and 669 controls. We then evaluated polymorphisms that showed the strongest association with acute kidney injury in a replication patient population containing 206 cases with 1,406 controls. We observed an association between acute kidney injury and four single-nucleotide polymorphisms at two independent loci on metaanalysis of discovery and replication populations. These include rs62341639 (metaanalysis P = 2.48 × 10^-7; odds ratio [OR], 0.64; 95% confidence interval [CI], 0.55-0.76) and rs62341657 (P = 3.26 × 10^-7; OR, 0.65; 95% CI, 0.55-0.76) on chromosome 4 near APOL1-regulator IRF2, and rs9617814 (metaanalysis P = 3.81 × 10^-6; OR, 0.70; 95% CI, 0.60-0.81) and rs10854554 (P = 6.53 × 10^-7; OR, 0.67; 95% CI, 0.57-0.79) on chromosome 22 near acute kidney injury-related gene TBX1.

CONCLUSIONS

Our findings reveal two genetic loci that are associated with acute kidney injury. Additional studies should be conducted to functionally evaluate these loci and to identify other common genetic variants contributing to acute kidney injury.

Anesthetic Management of Patients Undergoing Percutaneous Endocardial and Epicardial Left Atrial Appendage Occlusion

Atrial fibrillation is the most common cardiac arrhythmia in adults affecting almost 6 million adults in the United States. The 2 most common comorbidities associated with atrial fibrillation are heart failure and thromboembolic events. Heart failure symptoms may be treated with rate control, antiarrhythmic medications or by catheter ablation. Unfortunately, despite optimal medical management, thromboembolic events still occur. Recently, there has been a great deal of interest and innovation in finding an alternative to chronic anticoagulation. Several percutaneous left atrial appendage occlusion devices have been developed over recent years, some of which have proven to be noninferior to anticoagulation in preventing strokes in atrial fibrillation patients. The 2 most widely used left atrial appendage occlusion devices are the WATCHMAN (Atritech Inc, Plymouth, MN, USA) and the LARIAT (SentreHEART, Palo Alto, CA, USA) devices. After a detailed description of the procedures, the anesthetic considerations of each procedure and management of specific adverse events are discussed within this review.

Anesthetic Management in Radiofrequency Catheter Ablation of Ventricular Tachycardia

Radiofrequency catheter ablation is increasingly being used to treat patients who have ventricular tachycardia, and anesthesiologists frequently manage their perioperative care. This narrative review is intended to familiarize anesthesiologists with preprocedural, intraprocedural, and postprocedural implications of this ablation. Ventricular tachycardia typically arises from structural heart disease, most often from scar tissue after myocardial infarction. Many patients thus affected will benefit from radiofrequency catheter ablation in the electrophysiology laboratory to ablate the foci of arrhythmogenesis. The pathophysiology of ventricular tachycardia is complex, as are the technical aspects of mapping and ablating these arrhythmias. Patients often have substantial comorbidities and tenuous hemodynamic status, necessitating pharmacologic and mechanical cardiopulmonary support. General anesthesia and monitored anesthesia care, when used for sedation during ablation, can lead to drug interactions and side effects in the presence of ventricular tachycardia, so anesthesiologists should also be aware of potential perioperative complications. We discuss variables that can help anesthesiologists safely guide patients through the challenges of radiofrequency catheter ablation of ventricular tachycardia.

Duration of Postoperative Atrial Fibrillation After Cardiac Surgery Is Associated With Worsened Long-Term Survival

BACKGROUND

Studies of the effects of postoperative atrial fibrillation (poAF) on long-term survival are conflicting, likely because of comorbidities that occur with poAF and the patient populations studied. Furthermore, the effects of poAF duration on long-term survival are poorly understood.

METHODS

We utilized a prospectively collected database on outcomes of cardiac surgery at a large tertiary care institution between August 2001 and December 2010 with survival follow-up through June 2015 to analyze long-term survival of patients with poAF. In addition, we identified patient- and procedure-related variables associated with poAF, and estimated overall comorbidity burden using the Elixhauser comorbidity index. Survival was compared between patients with poAF (n = 513) and a propensity score matched control cohort, both for all patients and separately for subgroups of patients with poAF lasting less than 2 days (n = 218) and patients with prolonged poAF (n = 265).

RESULTS

Patients with poAF were older and had a higher burden of comorbidities. Survival was significantly worse for patients with poAF than for the matched control group (hazard ratio 1.43, 95% confidence interval: 1.11 to 1.86). That was driven by decreased survival among patients with prolonged poAF (hazard ratio 1.97, 95% confidence interval: 1.37 to 2.80), whereas survival of patients with poAF for less than 2 days was not significantly different from that of matched controls (hazard ratio 0.91, 95% confidence interval: 0.60 to 1.39).

CONCLUSIONS

After close matching based on comorbidity burden, prolonged poAF is still associated with decreased survival. Therefore, vigilance is warranted in monitoring and treating patients with prolonged poAF after cardiac surgery.

Length Polymorphisms in Heme Oxygenase-1 and AKI after Cardiac Surgery

Heme oxygenase-1 (HO-1) catalyzes the degradation of heme, which may be involved in the pathogenesis of AKI. Length polymorphisms in the number of GT dinucleotide repeats in the HO-1 gene (HMOX1) promoter inversely associate with HMOX1 mRNA expression. We analyzed the association between allelic frequencies of GT repeats in the HMOX1 gene promoter and postoperative AKI in 2377 white patients who underwent cardiac surgery with cardiopulmonary bypass. We categorized patients as having the short allele (S; <27 GT repeats) or long allele (L; ≥27 GT repeats), and defined AKI as an increase in serum creatinine ≥0.3 mg/dl within 48 hours or ≥50% within 5 days, or the need for RRT. Compared with patients with the SS genotype, patients with the LL genotype had 1.58-fold (95% confidence interval, 1.06 to 2.34; P=0.02) higher odds of AKI. After adjusting for baseline and operative characteristics, the odds ratio for AKI per L allele was 1.26 (95% confidence interval, 1.05 to 1.50; P=0.01). In conclusion, longer GT repeats in the HMOX1 gene promoter associate with increased risk of AKI after cardiac surgery, consistent with heme toxicity as a pathogenic feature of cardiac surgery-associated AKI, and with HO-1 as a potential therapeutic target.

Genetic and clinical risk prediction model for postoperative atrial fibrillation

BACKGROUND

Postoperative atrial fibrillation (PoAF) is common after coronary artery bypass grafting. We previously showed that atrial fibrillation susceptibility single nucleotide polymorphisms (SNPs) at the chromosome 4q25 locus are associated with PoAF. Here, we tested the hypothesis that a combined clinical and genetic model incorporating atrial fibrillation risk SNPs would be superior to a clinical-only model.

METHODS AND RESULTS

We developed and externally validated clinical and clinical/genetic risk models for PoAF. The discovery and validation cohorts included 556 and 1164 patients, respectively. Clinical variables previously associated with PoAF and 13 SNPs at loci associated with atrial fibrillation in genome-wide association studies were considered. PoAF occurred in 30% and 29% of patients in the discovery and validation cohorts, respectively. In the discovery cohort, a logistic regression model with clinical factors had good discrimination, with an area under the receiver operator characteristic curve of 0.76. The addition of 10 SNPs to the clinical model did not improve discrimination (area under receiver operator characteristic curve, 0.78; P=0.14 for difference between the 2 models). In the validation cohort, the clinical model had good discrimination (area under the receiver operator characteristic curve, 0.69) and addition of genetic variables resulted in a marginal improvement in discrimination (area under receiver operator characteristic curve, 0.72; P<0.0001).

CONCLUSIONS

We developed and validated a model for the prediction of PoAF containing common clinical variables. Addition of atrial fibrillation susceptibility SNPs did not improve model performance. Tools to accurately predict PoAF are needed to risk stratify patients undergoing coronary artery bypass grafting and identify candidates for prophylactic therapies.

Plasma corin decreases after coronary artery bypass graft surgery and is associated with postoperative heart failure: a pilot study

OBJECTIVE

Corin is a natriuretic peptide-converting enzyme that cleaves precursor pro-B-type natriuretic peptide to active B-type natriuretic peptide (BNP) (diuretic, natriuretic, and vasodilatory properties). Increased plasma BNP is a known diagnostic and prognostic heart failure (HF) biomarker in ambulatory and surgical patients. Recent studies indicate that plasma corin is decreased significantly in chronic HF patients, yet perioperative plasma corin concentrations have not been assessed in cardiac surgical patients. The objectives of this study were to determine the effect of coronary artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB) on plasma corin concentrations and to assess the association between change in perioperative plasma corin concentration and long-term postoperative HF hospitalization or death. It was hypothesized that plasma corin concentrations decrease significantly from preoperative baseline during postoperative days 1 to 4 and that hospitalization or death from HF during the 5 years after surgery is associated with higher relative difference (preoperative baseline to postoperative nadir) in plasma corin concentrations.

DESIGN

Prospective observational pilot study.

SETTING

Two institutions: Brigham and Women's Hospital, Boston, Massachusetts and the Texas Heart Institute, St. Luke's Hospital, Houston, Texas.

PARTICIPANTS

99 patients of European ancestry who underwent isolated primary CABG surgery with CPB.

INTERVENTIONS

Nonemergency isolated primary CABG surgery with CPB.

MEASUREMENTS AND MAIN RESULTS

Plasma corin concentration was assessed preoperatively and at 4 postoperative time points (postoperative days 1-4). HF hospitalization or HF death events during the 5 years after surgery were identified by review of hospital and death records. Postoperative plasma corin concentrations were significantly lower than preoperative baseline concentrations (p<0.0001). Perioperative corin concentrations were significantly higher in males than in females (p<0.0001). Fifteen patients experienced long-term postoperative HF events. Patients who experienced HF hospitalization or HF death during study follow-up had significantly higher relative difference in plasma corin concentration (preoperative baseline to postoperative nadir) than patients who did not experience HF events during study follow-up (p=0.03).

CONCLUSIONS

Plasma corin concentrations decrease significantly from preoperative concentrations after CABG surgery. HF hospitalization or HF death during the 5 years after CABG surgery with CPB is associated with larger relative decrease in plasma corin concentration from preoperative baseline. Further investigation is warranted to determine the role of corin in postoperative HF biology.

Genetic Variants Associated With Atrial Fibrillation and PR Interval Following Cardiac Surgery

OBJECTIVE

The authors hypothesized that genetic association between atrial fibrillation (AF)-associated and PR-associated genetic loci was biologically mediated through slower conduction velocities for some or all of these loci.

DESIGN

Prospectively collected cohort study.

SETTING

Single tertiary care university hospital.

PARTICIPANTS

A total of 1227 Caucasian patients who underwent coronary artery bypass grafting (CABG).

INTERVENTIONS

A total of 677 single nucleotide polymorphisms previously associated with ambulatory AF or PR interval were tested for association with postoperative atrial fibrillation (poAF) and preoperative PR interval, maximum PR interval, maximum change in PR interval, and maximum change in PR interval from preoperative PR interval.

MEASUREMENTS AND MAIN RESULTS

The incidence of new-onset poAF was 31%. All of the PR interval variables were longer in the poAF cohort. Two variants on 1q21 and 12 on 4q25 were associated with poAF after adjustment for false discovery rate (FDR), but no variants were associated with PR interval variables after adjustment for FDR. Several variants were associated with both poAF and PR interval variables at p<0.05, but none of them remained significant after adjusting for FDR.

CONCLUSION

It was found that patients with poAF have significantly longer PR interval. Genetic variants in both the 1q21 and 4q25 regions associate with poAF after CABG surgery, but the authors were unable to find association between these variants and PR interval after adjusting for FDR.

Increased perioperative b-type natriuretic peptide associates with heart failure hospitalization or heart failure death after coronary artery bypass graft surgery

BACKGROUND

Heart failure (HF) is a leading cause of hospitalization and mortality. Plasma B-type natriuretic peptide (BNP) is an established diagnostic and prognostic ambulatory HF biomarker. We hypothesized that increased perioperative BNP independently associates with HF hospitalization or HF death up to 5 yr after coronary artery bypass graft surgery.

METHODS

The authors conducted a two-institution, prospective, observational study of 1,025 subjects (mean age = 64 ± 10 yr SD) undergoing isolated primary coronary artery bypass graft surgery with cardiopulmonary bypass. Plasma BNP was measured preoperatively and on postoperative days 1-5. The study outcome was hospitalization or death from HF, with HF events confirmed by reviewing hospital and death records. Cox proportional hazards analyses were performed with multivariable adjustments for clinical risk factors. Preoperative and peak postoperative BNP were added to the multivariable clinical model in order to assess additional predictive benefit.

RESULTS

One hundred five subjects experienced an HF event (median time to first event = 1.1 yr). Median follow-up for subjects who did not have an HF event = 4.2 yr. When individually added to the multivariable clinical model, higher preoperative and peak postoperative BNP concentrations each, independently associated with the HF outcome (log10 preoperative BNP hazard ratio = 1.93; 95% CI, 1.30-2.88; P = 0.001; log10 peak postoperative BNP hazard ratio = 3.38; 95% CI, 1.45-7.65; P = 0.003).

CONCLUSIONS

Increased perioperative BNP concentrations independently associate with HF hospitalization or HF death during the 5 yr after primary coronary artery bypass graft surgery. Clinical trials may be warranted to assess whether medical management focused on reducing preoperative and longitudinal postoperative BNP concentrations associates with decreased HF after coronary artery bypass graft surgery.

Polymorphism in the protease-activated receptor-4 gene region associates with platelet activation and perioperative myocardial injury

Protease-activated receptors (PAR)-1 and -4 are the principal receptors for thrombin-mediated platelet activation. Functional genetic variation has been described in the human PAR1 gene, but not in the PAR4 gene (F2RL3). We sought to identify variants in and around F2RL3 and to determine their association with perioperative myocardial injury (PMI) after coronary artery bypass graft surgery. We further explored possible mechanisms for F2RL3 single nucleotide polymorphism (SNP) associations with PMI including altered receptor expression and platelet activation. Twenty-three SNPs in the F2RL3 gene region were genotyped in two phases in 934 Caucasian subjects. Platelets from 43 subjects (23 major allele, 20 risk allele) homozygous for rs773857 (SNP with the strongest association with PMI) underwent flow cytometry to assess PAR4 receptor number and response to activation by a specific PAR4 activating peptide (AYPGKF) measured by von Willebrand factor (vWf) binding and P-selectin release and PAC-1 binding. We identified a novel association of SNP rs773857 with PMI (OR = 2.4, P = 0.004). rs773857 risk allele homozygotes have significantly increased platelet counts and platelets showed a significant increase in P-selectin release after activation (P = 0.004). We conclude that rs773857 risk allele homozygotes are associated with risk for increased platelet count and hyperactivity.

Subclinical changes in serum creatinine and mortality after coronary artery bypass grafting

BACKGROUND

Changes in postoperative serum creatinine levels have been used to define acute renal injury in patients undergoing cardiac surgery with cardiopulmonary bypass. It remains unclear, however, whether subclinical increases in serum creatinine that do not meet current Acute Kidney Injury Network or RIFLE (risk, injury, failure, loss, and end-stage kidney disease) criteria for acute renal injury are predictive of mortality after cardiac surgery.

METHODS

Multivariate logistic regression was performed in a retrospective cohort of 3914 consecutive patients undergoing primary, isolated coronary artery bypass grafting with cardiopulmonary bypass to determine whether postoperative serum creatinine change independently predicts 30-day all-cause mortality in patients with normal renal function and with varying levels of preoperative renal insufficiency. To control further for selection bias, multivariate logistic regression was performed on a propensity-matched cohort (n = 2042) to determine whether subclinical increases in serum creatinine predict mortality.

RESULTS

Negative change in serum creatinine was associated with reduced 30-day all-cause mortality. Even subclinical increases in serum creatinine were associated with increased mortality relative to patients with negative changes in serum creatinine (odds ratio, 3.93; 95% confidence interval, 1.68-9.22; P < .01). After propensity matching, subclinical increases in serum creatinine were still associated with increased mortality (odds ratio, 4.13; 95% confidence interval, 1.37-12.45; P = .01).

CONCLUSIONS

Subclinical increases in serum creatinine that do not meet acute renal injury criteria are independently associated with 30-day all-cause mortality in patients with normal renal function or preoperative renal insufficiency undergoing coronary artery bypass grafting.

Genome-wide assessment for genetic variants associated with ventricular dysfunction after primary coronary artery bypass graft surgery

Background

Postoperative ventricular dysfunction (VnD) occurs in 9–20% of coronary artery bypass graft (CABG) surgical patients and is associated with increased postoperative morbidity and mortality. Understanding genetic causes of postoperative VnD should enhance patient risk stratification and improve treatment and prevention strategies. We aimed to determine if genetic variants associate with occurrence of in-hospital VnD after CABG surgery.

Methods

A genome-wide association study identified single nucleotide polymorphisms (SNPs) associated with postoperative VnD in male subjects of European ancestry undergoing isolated primary CABG surgery with cardiopulmonary bypass. VnD was defined as the need for ≥2 inotropes or mechanical ventricular support after CABG surgery. Validated SNPs were assessed further in two replication CABG cohorts and meta-analysis was performed.

Results

Over 100 SNPs were associated with VnD (P<10⁻⁴), with one SNP (rs17691914) encoded at 3p22.3 reaching genome-wide significance (P_{additive model} = 2.14×10⁻⁸). Meta-analysis of validation and replication study data for 17 SNPs identified three SNPs associated with increased risk for developing postoperative VnD after adjusting for clinical risk factors. These SNPs are located at 3p22.3 (rs17691914, OR_{additive model} = 2.01, P = 0.0002), 3p14.2 (rs17061085, OR_{additive model} = 1.70, P = 0.0001) and 11q23.2 (rs12279572, OR_{recessive model} = 2.19, P = 0.001).

Conclusions

No SNPs were consistently associated with strong risk (OR_{additive model}>2.1) of developing in-hospital VnD after CABG surgery. However, three genetic loci identified by meta-analysis were more modestly associated with development of postoperative VnD. Studies of larger cohorts to assess these loci as well as to define other genetic mechanisms and related biology that link genetic variants to postoperative ventricular dysfunction are warranted.

Chromosome 9p21 variant predicts mortality after coronary artery bypass graft surgery

BACKGROUND

Recent genome-wide association studies have identified several chromosome 9p21 single nucleotide polymorphisms associated with coronary artery disease and myocardial infarction in nonsurgical populations. We have recently demonstrated an independent association between these 9p21 variants and perioperative myocardial injury after isolated primary coronary artery bypass graft (CABG) surgery. This study investigated the association of a 9p21 variant with mortality in patients after CABG surgery and its prognostic value to improve the EuroSCORE.

METHODS AND RESULTS

In a 2-center, prospective, observational study of 846 white primary CABG surgery patients, we genotyped rs10116277, the 9p21 variant with the strongest association to perioperative myocardial injury in our cohort. To estimate the utility of rs10116277 for predicting all-cause mortality within 5 years after surgery, a Cox proportional hazard model was constructed to estimate the hazard ratios (HR) and 95% confidence intervals (CI) while adjusting for demographics and clinical covariates. The homozygote minor allele of rs10116277 was associated with significantly increased risk of all-cause mortality even after adjusting for other clinical predictors of mortality in a Cox proportional hazards model (HR, 1.7; 95% CI, 1.1-2.7; P=0.026). Addition of rs10116277 to the logistic EuroSCORE also significantly improved model prediction for mortality (HR, 1.82; 95% CI, 1.15-2.88; P=0.01).

CONCLUSIONS

The 9p21 variant rs10116277 is independently associated with all-cause mortality after primary CABG surgery in whites and significantly improves the predictive value of the logistic EuroSCORE. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT00281164.

Heart-type fatty acid binding protein is an independent predictor of death and ventricular dysfunction after coronary artery bypass graft surgery

BACKGROUND

Heart-type fatty acid binding protein (hFABP) functions as a myocardial fatty acid transporter and is released into the circulation early after myocardial injury. We hypothesized that hFABP is superior to conventional cardiac biomarkers for predicting early perioperative myocardial injury after coronary artery bypass graft (CABG) surgery.

METHODS

A prospective cohort study of 1298 patients undergoing primary CABG with cardiopulmonary bypass (CPB) was performed at 2 institutions. Four plasma myocardial injury biomarkers (hFABP; cardiac troponin I [cTnI]; creatine kinase, MB [CK-MB] fraction; and myoglobin) were measured at 7 perioperative time points. The association among perioperative cardiac biomarkers and ventricular dysfunction, hospital length of stay (HLOS), and up to 5-year postoperative mortality (median 3.3 years) was assessed using Cox proportional hazard models. We defined in-hospital ventricular dysfunction as a new requirement for 2 or more inotropes, or new placement of an intraaortic balloon pump, or ventricular assist device either during the intraoperative period after the patient separated from CPB or postoperatively in the intensive care unit.

RESULTS

The positive and negative predictive values of mortality for hFABP are 13% (95% confidence interval [CI], 9%-19%) and 95% (95% CI, 94%-96%), respectively, which is higher than for cTnI and CK-MB. After adjusting for clinical predictors, both postoperative day (POD) 1 and peak hFABP levels were independent predictors of ventricular dysfunction (P < 0.0001), HLOS (P < 0.05), and 5-year mortality (P < 0.0001) after CABG surgery. Furthermore, POD1 and peak hFABP levels were significantly superior to other evaluated biomarkers for predicting mortality. In a repeated-measures analysis, hFABP outperformed all other models of fit for HLOS. Patients with POD2 hFABP levels higher than post-CPB hFABP levels had an increased mortality compared with those patients whose POD2 hFABP levels decreased from their post-CPB level (hazard ratio, 10.9; 95% CI, 5.0-23.7; P = 7.2 × 10(-10)). Mortality in the 120 patients (10%) with a later hFABP peak was 18.3%, compared with 4.7% in those who did not peak later. Alternatively, for cTnI or CK-MB, no difference in mortality was detected.

CONCLUSION

Compared with traditional markers of myocardial injury after CABG surgery, hFABP peaks earlier and is a superior independent predictor of postoperative mortality and ventricular dysfunction.

Preoperative evaluation and preparation of the patient for cardiac surgery

Cardiac surgery is associated with significant morbidity, mortality, and socioeconomic costs. Preoperative assessment assists the clinician in identifying potential complications and facilitates discussion of these risks with the patient. Careful patient selection and preparation during preoperative evaluation may minimize morbidity, mortality, and resource use. This article outlines a system-based approach to preoperative evaluation and preparation of the patient undergoing cardiac surgery.

Common genetic variants on chromosome 9p21 predict perioperative myocardial injury after coronary artery bypass graft surgery

OBJECTIVE

Approximately 10% of patients undergoing cardiac surgery have perioperative myocardial injury. A recent genome-wide association study identified an association between myocardial infarction in nonsurgical populations and common genetic variants on chromosome 9p21. We hypothesized that these variants are also associated with perioperative myocardial injury after isolated primary coronary artery bypass graft surgery.

METHODS

In a prospective observational study of 846 Caucasian patients undergoing primary coronary bypass surgery at 2 US centers, we genotyped 61 linkage-disequilibrium tagging single nucleotide polymorphisms, encompassing 436 kbp of the 9p21 region. A multivariable logistic model was used to adjust for previously identified clinical covariates of perioperative myocardial injury. Perioperative myocardial injury was defined as a postoperative day 1 cardiac troponin I in the top 10th percentile (>9.13 microg/L) of the cohort. Multiple testing of single nucleotide polymorphisms was corrected for with family-wise errors.

RESULTS

Prior myocardial infarction and longer cardiopulmonary bypass time were significant independent predictors of perioperative myocardial injury. Levels of postoperative cardiac troponin I were incrementally increased for each additional copy of the risk alleles of 3 single nucleotide polymorphisms: rs10116277, rs6475606, and rs2383207. Adjusted additive odds ratios ranged between 1.64 and 1.79 (asymptotic P value between 3.7 x 10(-3) and 6 x 10(-4)) and remained significantly associated with perioperative myocardial injury even after accounting for clinical covariates including severity of coronary disease, and multiple comparisons.

CONCLUSIONS

We have now demonstrated that common genetic variants in the same 9p21 locus, previously known to be associated with myocardial infarction in nonsurgical populations, are also associated with perioperative myocardial injury after coronary artery bypass grafting. Further investigation is warranted to elucidate functional mechanisms.

Postoperative activity, but not preoperative activity, of antithrombin is associated with major adverse cardiac events after coronary artery bypass graft surgery

BACKGROUND

Low levels of antithrombin (AT) have been independently associated with prolonged intensive care unit stay and an increased incidence of neurologic and thromboembolic events after cardiac surgery. We hypothesized that perioperative AT activity is independently associated with postoperative major adverse cardiac events (MACEs) in patients undergoing coronary artery bypass graft (CABG) surgery.

METHODS

We prospectively studied 1403 patients undergoing primary CABG surgery with cardiopulmonary bypass (CPB) (http://clinicaltrials.gov/show/NCT00281164). The primary clinical end point was occurrence of MACE, defined as a composite outcome of any one or more of the following: postoperative death, reoperation for coronary graft occlusion, myocardial infarction, stroke, pulmonary embolism, or cardiac arrest until first hospital discharge. Plasma AT activity was measured before surgery, after post-CPB protamine, and on postoperative days (PODs) 1-5. Multivariate logistic regression modeling was performed to estimate the independent effect of perioperative AT activity upon MACE.

RESULTS

MACE occurred in 146 patients (10.4%), consisting of postoperative mortality (n = 12), myocardial infarction (n = 108), stroke (n = 17), pulmonary embolism (n = 8), cardiac arrest (n = 16), or a subsequent postoperative or catheter-based treatment for graft occlusion (n = 6). AT activity at baseline did not differ between patients with (0.91 ± 0.13 IU/mL; n = 146) and without (0.92 ± 0.13 IU/mL; n = 1257) (P = 0.18) MACE. AT activity in both groups was markedly reduced immediately after CPB and recovered to baseline values over the ensuing 5 PODs. Postoperative AT activity was significantly lower in patients with MACE than those without MACE. After adjustment for clinical predictors of MACE, AT activity on PODs 2 and 3 was associated with MACE.

CONCLUSIONS

Preoperative AT activity is not associated with MACE after CABG surgery. MACE is independently associated with postoperative AT activity but only at time points occurring predominantly after the MACE.

Preoperative evaluation and preparation of the patient for cardiac surgery

Cardiac surgery is associated with significant morbidity, mortality, and socioeconomic costs. Preoperative assessment assists the clinician in identifying potential complications and facilitates discussion of these risks with the patient. Careful patient selection and preparation during preoperative evaluation may minimize morbidity, mortality, and resource use. This article outlines a system-based approach to preoperative evaluation and preparation of the patient undergoing cardiac surgery.

Variation in the 4q25 chromosomal locus predicts atrial fibrillation after coronary artery bypass graft surgery

BACKGROUND

Atrial fibrillation (AF) is the most common adverse event following coronary artery bypass graft surgery. A recent study identified chromosome 4q25 variants associated with AF in ambulatory populations. However, their role in postoperative AF is unknown. We hypothesized that genetic variants in the 4q25 chromosomal region are independently associated with postoperative AF after coronary artery bypass graft surgery.

METHODS AND RESULTS

Two prospectively collected cohorts of patients undergoing coronary artery bypass graft surgery, with or without concurrent valve surgery, at 3 US centers. From a discovery cohort of 959 patients, clinical and genomic multivariate predictors of postoperative AF were identified by genotyping 45 single-nucleotide polymorphisms (SNPs) encompassing the 4q25 locus. Three SNPs were then assessed in a separately collected validation cohort of 494 patients. After adjustment for clinical predictors of postoperative AF and multiple comparisons, rs2200733, rs13143308, and 5 other linked SNPs independently predicted postoperative AF in the discovery cohort. Additive odds ratios for the 7 associated 4q25 SNPs ranged between 1.57 and 2.17 (P=8.0x10(-4) to 3.4x10(-6)). Association with postoperative AF were measured and replicated for rs2200733 and rs13143308 in the validation cohort.

CONCLUSIONS

In 2 independently collected cardiac surgery cohorts, noncoding SNPs within the chromosome 4q25 region are independently associated with postoperative AF after coronary artery bypass graft surgery after adjusting for clinical covariates and multiple comparisons.

C-Reactive protein gene variants are associated with postoperative C-reactive protein levels after coronary artery bypass surgery

Background

Elevated baseline C-reactive protein (CRP) levels are associated with increased risk for developing cardiovascular disease. Several CRP gene variants have been associated with altered baseline CRP levels in ambulatory populations. However, the influence of CRP gene variants on CRP levels during inflammatory states, such as surgery, is largely unexplored. We describe the association between candidate CRP gene variants and postoperative plasma CRP levels in patients undergoing primary, elective coronary artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB).

Methods

Using a multicenter candidate gene association study design, we examined the association between seventeen candidate CRP single nucleotide polymorphisms (SNPs) and inferred haplotypes, and altered postoperative CRP levels in 604 patients undergoing CABG surgery with CPB. Perioperative CRP levels were measured immediately prior to surgery, post-CPB and on postoperative days (POD) 1–4.

Results

CRP levels were significantly elevated at all postoperative time points when compared with preoperative levels (P < 0.0001). After adjusting for clinical covariates, the minor allele of the synonymous coding SNP, rs1800947 was associated with lower peak postoperative CRP levels (P = 2.4 × 10^-4) and lower CRP levels across all postoperative time points (P = 4.8 × 10^-5). rs1800947 remained highly significant after Bonferroni adjustment for multiple comparisons.

Conclusion

We identified a CRP gene SNP associated with lower postoperative CRP levels in patients undergoing CABG surgery with CPB. Further investigation is needed to clarify the significance of this association between CRP gene variants and the acute-phase rise in postoperative CRP levels with regard to the risk of adverse postoperative outcomes.

Troponin is superior to electrocardiogram and creatinine kinase MB for predicting clinically significant myocardial injury after coronary artery bypass grafting

AIMS

Cardiac biomarkers are routinely elevated after uncomplicated cardiac surgery to levels considered diagnostic of myocardial infarction in ambulatory populations. We investigated the diagnostic power of electrocardiogram (ECG) and cardiac biomarker criteria to predict clinically relevant myocardial injury using benchmarks of mortality and increased hospital length of stay (HLOS) in patients undergoing coronary artery bypass graft (CABG) surgery.

METHODS AND RESULTS

Perioperative ECGs, creatinine kinase MB fraction, and cardiac troponin I (cTnI) were assessed in 545 primary CABG patients. None of the ECG criteria for myocardial injury predicted mortality or HLOS. However, post-operative day (POD) 1 cTnI levels independently predicted 5-year mortality (hazard ratio = 1.42; 95% CI 1.14-1.76 for each 10 microg/L increase; P = 0.009), while adjusting for baseline demographic characteristics and perioperative risk factors. Moreover, cTnI was the only biomarker that significantly improved the prediction of 5-year mortality estimated by the logistic Euroscore (P = 0.02). Furthermore, the predictive value of cTnI for 5-year mortality was replicated in a separately collected cohort of 1031 CABG patients using cardiac troponin T.

CONCLUSION

Electrocardiogram diagnosis of post-operative myocardial injury after CABG does not independently predict an increased risk of 5-year mortality or HLOS. Conversely, cTnI is independently associated with an increased risk of mortality and prolonged HLOS.

Obesity is associated with increased morbidity after coronary artery bypass graft surgery in patients with renal insufficiency

OBJECTIVE

Although obesity is a major risk factor for cardiovascular disease, it is not clear whether obesity increases the risk of postoperative morbidity and mortality in patients undergoing coronary artery bypass grafting surgery. Increasing evidence suggests that both obesity and renal insufficiency are associated with increased systemic inflammation, thrombogenicity, and endothelial dysfunction. Cardiac surgical patients with comorbid obesity and renal insufficiency might thus be at greater risk for systemic proinflammatory and thrombotic states, which in turn might increase the risk of adverse perioperative outcomes. We investigated the influence of obesity on adverse postoperative outcomes after coronary artery bypass grafting surgery in patients with and without renal insufficiency.

METHODS

A retrospective cohort study was performed of patients (n = 10,863) undergoing primary coronary artery bypass grafting surgery with cardiopulmonary bypass between January 1995 and June 2005. Patients with preoperative renal insufficiency (n = 1385) and patients with preoperative normal renal function (n = 9478) were further classified as obese (body mass index, > or =30 kg/m(2)) or nonobese (body mass index, 18.5-29.9 kg/m(2)). Multivariate, stepwise logistic regression was performed, controlling for demographic factors, medications, and perioperative risk factors to determine whether obesity is independently associated with an increased risk of adverse postoperative outcomes after coronary artery bypass grafting surgery in patients with or without renal insufficiency.

RESULTS

Obese patients with preoperative renal insufficiency had higher rates of postoperative myocardial infarction (5.9% vs 3.4%) and low cardiac output syndrome (24.5% vs 18.6%) and increased hospital stay (14.9 +/- 13.7 vs 13.2 +/- 13.0 days) than nonobese patients with preoperative renal insufficiency (all outcomes, P < .05). Multivariate analysis revealed that obese patients with preoperative renal insufficiency were independently associated with an increased risk of postoperative myocardial infarction (odds ratio, 1.82; 95% confidence interval, 1.07-3.07; P < .05) and low cardiac output syndrome (odds ratio, 1.53; 95% confidence interval, 1.15-2.03; P < .01) and increased hospital stay (P < .05). In contrast, obese patients with normal preoperative renal function were independently associated only with an increased risk of postoperative sternal wound infection (odds ratio, 2.55; 95% confidence interval, 1.40-4.67; P < .01) and leg wound infection (odds ratio, 2.27; 95% confidence interval, 1.71-3.02; P < .01).

CONCLUSION

Obesity is an independent risk factor for increased cardiovascular morbidity and prolonged hospital stay in patients with preoperative renal insufficiency undergoing primary coronary artery bypass grafting surgery.

Preoperative B-type natriuretic peptide is as independent predictor of ventricular dysfunction and mortality after primary coronary artery bypass grafting

OBJECTIVE

Elevated B-type natriuretic peptide is associated with increased morbidity and mortality in ambulatory patients with congestive heart failure or acute coronary syndromes. Its utility in predicting adverse cardiac surgical outcomes is less certain. We hypothesized that preoperative plasma B-type natriuretic peptide would independently predict in-hospital postoperative ventricular dysfunction, hospital stay, and up to 5-year mortality after primary coronary artery bypass grafting.

METHODS

This is a prospective, longitudinal study of 1023 patients at two institutions undergoing primary coronary artery bypass grafting with cardiopulmonary bypass. Ventricular dysfunction was defined as requirement for at least two inotropes or new intra-aortic balloon pump or ventricular assist device support after coronary artery bypass grafting. Multivariable analyses assessed independent roles of preoperative B-type natriuretic peptide in predicting postoperative ventricular dysfunction, hospital stay, and 5-year all-cause mortality.

RESULTS

Preoperative plasma B-type natriuretic peptide concentration predicted ventricular dysfunction, hospital stay, and mortality in univariate and multivariable analyses. Logistic regression demonstrated preoperative B-type natriuretic peptide to independently predict ventricular dysfunction (odds ratio 1.92, 95% confidence interval 1.12-3.29, P = .018), after adjustment for preoperative left ventricular ejection fraction, congestive heart failure severity, and other clinical predictors. Multivariable Cox proportional hazards models showed preoperative B-type natriuretic peptide to independently predict hospital stay (hazard ratio 1.42, 95% confidence interval 1.18-1.72, P = .0002) and mortality (hazard ratio 1.89, 95% confidence interval 1.08-3.33, P = .026).

CONCLUSION

Preoperative plasma B-type natriuretic peptide independently predicted in-hospital ventricular dysfunction, hospital stay, and up to 5-year all-cause mortality after primary coronary artery bypass grafting.

The MBL2 'LYQA secretor' haplotype is an independent predictor of postoperative myocardial infarction in whites undergoing coronary artery bypass graft surgery

BACKGROUND

Mannose-binding lectin (MBL) is an important component of innate immunity and activator of the lectin complement pathway. Within the MBL2 gene are seven 5' "secretor" haplotypes that code for altered serum MBL levels and complement activation. However, recent evidence suggests that 3' MBL2 haplotypes may also modify MBL function and circulating levels. Because MBL and the lectin complement pathway have been implicated in cardiovascular injury, we investigated whether MBL2 haplotypes are independently associated with an increased risk of postoperative myocardial infarction (PMI) in patients undergoing coronary artery bypass graft surgery.

METHODS AND RESULTS

Genotyping of 18 polymorphic sites within the MBL2 gene was performed in a prospective, longitudinal multi-institutional study of 978 patients undergoing primary coronary artery bypass graft-only surgery with cardiopulmonary bypass between August 2001 and May 2005. After adjustment for multiple comparisons by permutation testing, multivariate, stepwise logistic regression, including a score test, was performed controlling for patient demographics, preoperative risk factors, medications, and intraoperative variables to determine if MBL2 secretor haplotypes are independent predictors of PMI in whites undergoing primary coronary artery bypass graft surgery. Neither the 5' nor 3' MBL2 haplotypes alone were associated with an increased incidence of PMI. However, the incidence of PMI in whites (n=843) expressing the combined MBL2 5' LYQA secretor haplotype (CGTCGG) and 3' haplotype (CGGGT) was significantly higher than in whites not expressing the haplotype (38% versus 10%; P<0.007). Moreover, the combined MBL2 LYQA secretor haplotype was an independent predictor of PMI in whites after primary coronary artery bypass graft surgery after adjustment for other covariates (P<0.02; adjusted OR: 3.97; 95% CI: 1.30 to 12.07). The combined MBL2 LYQA secretor haplotype in whites was also an independent predictor of postoperative CKMB levels exceeding 60 ng/mL (P<0.02; adjusted OR: 4.48; 95% CI: 1.95 to 16.80). Inclusion of the combined MBL2 LYQA secretor haplotype improved prediction models for PMI based on traditional risk factors alone (C-statistic 0.715 versus 0.705).

CONCLUSIONS

The combined MBL2 LYQA secretor haplotype is a novel independent predictor of PMI and may aid in preoperative risk stratification of whites undergoing primary coronary artery bypass graft surgery.

Fluorochrome-linked immunoassay for functional analysis of the mannose binding lectin complement pathway to the level of C3 cleavage

The humoral response to invading pathogens is mediated by a repertoire of innate immune molecules and receptors able to recognize pathogen-associated molecular patterns. Mannose binding lectin (MBL) and ficolins are initiation molecules of the lectin complement pathway (LCP) that bridge innate and adaptive immunity. Activation of the MBL-dependent lectin pathway, to the level of C3 cleavage, requires functional MASP-2, C2, C4 and C3, all of which have been identified with genetic polymorphisms that can affect protein concentration and function. Current assays for MBL and MASP-2 lack the ability to assess activation of all components to the level of C3 cleavage in a single assay platform. We developed a novel, low volume, fluorochrome linked immunoassay (FLISA) that quantitatively assesses the functional status of MBL, MASP-2 and C3 convertase in a single well. The assay can be used with plasma or serum. Multiple freeze/thaw cycles of serum do not significantly alter the assay, making it ideal for high throughput of large sample databases with minimal volume use. The FLISA can be used potentially to identify specific human disease correlations between these components and clinical outcomes in already established databases.

Non-antiarrhythmic agents for prevention of postoperative atrial fibrillation: role of statins

PURPOSE OF REVIEW

Atrial fibrillation is the most common arrhythmia following cardiac surgery, having both serious medical and socioeconomic consequences. Although there are established antiarrhythmic agents for preventing and treating postoperative atrial fibrillation, these therapies are neither 100% reliable, nor without risks and limitations. Thus, there remains a strong need for non-antiarrhythmic, adjunctive therapies for the prevention of postoperative atrial fibrillation.

RECENT FINDINGS

Long-term statin administration in ambulatory patients is associated with a reduced risk of adverse cardiovascular events, including death, myocardial infarction, stroke, renal dysfunction and atrial fibrillation. Recent evidence suggests, however, that statins may also reduce the risk of acute adverse outcomes following invasive procedures, including postoperative atrial fibrillation. Although the exact mechanisms by which statins may reduce postoperative atrial fibrillation are unclear, accumulating evidence suggests that statins exert multiple effects independent of their effect on LDL cholesterol. For example, in patients with acute coronary syndromes, statin therapy has been shown to modulate remodeling of the cardiac extracellular matrix and to reduce markers of inflammation, including C-reactive protein, serum amyloid A, tumor necrosis factor-alpha, and IL-6.

SUMMARY

Perioperative statin therapy may represent an important non-antiarrhythmic, adjunctive therapeutic strategy for the prevention of postoperative atrial fibrillation.

A Phase II, Double-Blind, Placebo-Controlled, Ascending-Dose Study of Eritoran (E5564), a Lipid A Antagonist, in Patients Undergoing Cardiac Surgery with Cardiopulmonary Bypass

BACKGROUND

Lipid A, the toxic moiety of endotoxin, is linked to multiple complications after cardiac surgery, including fever, vasodilation, and pulmonary and renal dysfunction. The lipid A antagonist eritoran (or E5564) prevents endotoxin-induced systemic inflammation in animals and humans. In this study we assessed the safety of eritoran administration in patients undergoing cardiac surgery and obtained preliminary efficacy data for the prophylaxis of endotoxin-mediated surgical complications.

METHODS

A double-blind, randomized, ascending-dose, placebo-controlled study was conducted at nine hospitals. Patients undergoing coronary artery bypass graft and/or cardiac valvular surgery with cardiopulmonary bypass were enrolled. Patients received a 4-h infusion of placebo (n = 78) vs 2 mg (n = 24), 12 mg (n = 26), or 28 mg (n = 24) of eritoran initiated approximately 1 h before cardiopulmonary bypass.

RESULTS

No significant safety concerns were identified with continuous safety monitoring, and enrollment continued to the highest prespecified dose (28 mg). No statistically significant differences were observed in most variables related to systemic inflammation or organ dysfunction/injury.

CONCLUSIONS

This Phase II safety study suggests that the administration of the novel lipid A antagonist, eritoran, is not associated with overt toxicity in cardiac surgical patients. Blocking lipid A with eritoran does not appear to confer any clear benefit to elective cardiac surgical patients.

Improved Postoperative Outcomes Associated with Preoperative Statin Therapy

Statin therapy is well established for prevention of cardiovascular disease. Statins may also reduce postoperative mortality and morbidity via a pleiotropic (non-lipid-lowering) effect. The authors conducted a meta-analysis to determine the influence of statin treatment on adverse postoperative outcomes in patients undergoing cardiac, vascular, or noncardiovascular surgery. Two independent authors abstracted data from 12 retrospective and 3 prospective trials (n = 223,010 patients). A meta-analysis was performed to evaluate the overall effect of preoperative statin therapy on postoperative outcomes. Preoperative statin therapy was associated with 38% and 59% reduction in the risk of mortality after cardiac (1.9% vs. 3.1%; P = 0.0001) and vascular (1.7% vs. 6.1%; P = 0.0001) surgery, respectively. When including noncardiac surgery, a 44% reduction in mortality (2.2% vs. 3.2%; P = 0.0001) was observed. Preoperative statin therapy may reduce postoperative mortality in patients undergoing surgical procedures. However, the statin associated effects on postoperative cardiovascular morbidity are too variable to draw any conclusion.

The role of statins in cancer therapy

Administration of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or statins, to ambulatory patients is associated with a lower incidence of long-term adverse cardiovascular events, including death, myocardial infarction, stroke, atrial fibrillation, and renal dysfunction. However, increasing clinical evidence suggests that statins, independent of their effects on serum cholesterol levels, may also play a potential role in the prevention and treatment of cancer. Specifically, statins have been shown to exert several beneficial antineoplastic properties, including decreased tumor growth, angiogenesis, and metastasis. The feasibility and efficacy of statins for the prevention and treatment of cancer is reviewed.

Preoperative statin therapy is associated with reduced cardiac mortality after coronary artery bypass graft surgery

OBJECTIVE

Statin therapy in ambulatory populations is associated with a significant reduction in adverse cardiovascular events, including death and myocardial infarction. Much less is known about the beneficial effects of statins on acute perioperative cardiovascular events. The purpose of this study was to determine whether preoperative statin therapy is associated with a reduced risk of early cardiac death or nonfatal, in-hospital postoperative myocardial infarction after primary, elective coronary artery bypass graft surgery requiring cardiopulmonary bypass.

METHODS

The Multicenter Study of Perioperative Ischemia (McSPI) Epidemiology II Study was a prospective, longitudinal study of 5436 patients undergoing coronary artery bypass graft surgery between November 1996 and June 2000 at 70 centers in 17 countries. The present study consisted of a pre-specified subset of these subjects divided into patients receiving (n = 1352) and not receiving (n = 1314) preoperative statin therapy. To control for potential bias related to use of statin therapy, the study estimated propensity scores by logistic regression to determine the predicted probability of inclusion in the "statin" group. Multivariate, stepwise logistic regression was then performed, controlling for patient demographics, medical history, operative characteristics, and propensity score to determine whether preoperative statin therapy was independently associated with a reduction in the risk of early (DOS-POD3) cardiac death and/or nonfatal, in-hospital postoperative myocardial infarction.

RESULTS

Preoperative statin therapy was independently associated with a significant reduction (adjusted odds ratio [OR] 0.25; 95% confidence intervals [CI] 0.07-0.87) in the risk of early cardiac death after primary, elective coronary bypass surgery (0.3% vs 1.4%; P < .03), but was not associated with a reduced risk of postoperative nonfatal, in-hospital myocardial infarction (7.9% vs 6.2%; P = not significant). Discontinuation of statin therapy after surgery was independently associated with a significant increase in late (POD4-discharge) all-cause mortality (adjusted OR 2.64; 95% CI 1.32-5.26) compared with continuation of statin therapy (2.64% vs 0.60%; P < .01). This was true even when controlling for the postoperative discontinuation of aspirin, beta-blocker, or angiotensin-converting enzyme inhibitor therapy. Discontinuation of statin therapy after surgery was also independently associated with a significant increase in late cardiac mortality (adjusted OR 2.95; 95% CI 1.31-6.66) compared with continuation of statin therapy (1.91% vs 0.45%; P < 0.01).

CONCLUSIONS

Preoperative statin use is associated with reduced cardiac mortality after primary, elective coronary artery bypass grafting. Postoperative statin discontinuation is associated with increased in-hospital mortality. Although further randomized trials are needed to confirm these findings, these data suggest the importance of perioperative statin administration.

Obesity in Diabetic Patients Undergoing Coronary Artery Bypass Graft Surgery Is Associated with Increased Postoperative Morbidity

Background

Despite the fact that obesity is a known risk factor for cardiovascular disease, many studies have failed to demonstrate that obesity is independently associated with an increased risk of cardiovascular morbidity and mortality in nondiabetic patients undergoing coronary artery bypass graft surgery. The authors investigated the influence of obesity on adverse postoperative outcomes in diabetic and nondiabetic patients after primary coronary artery bypass surgery.

Methods

A retrospective cohort study of patients undergoing primary coronary artery bypass surgery (n = 9,862) between January 1995 and December 2004 at the Texas Heart Institute was performed. Diabetic (n = 3,374) and nondiabetic patients (n = 6,488) were classified into five groups, according to their body mass index: normal weight (n = 2,148), overweight (n = 4,257), mild obesity (n = 2,298), moderate obesity (n = 785), or morbid obesity (n = 338). Multivariate, stepwise logistic regression was performed controlling for patient demographics, medical history, and preoperative medications to determine whether obesity was independently associated with an increased risk of adverse postoperative outcomes.

Results

Obesity in nondiabetic patients was not independently associated with an increased risk of adverse postoperative outcomes. In contrast, obesity in diabetic patients was independently associated with a significantly increased risk of postoperative respiratory failure (odds ratio [OR], 2.26; 95% confidence interval [CI], 1.41-3.61; P &lt; 0.001), ventricular tachycardia (OR, 2.27; 95% CI, 1.18-4.35; P &lt; 0.02), atrial fibrillation (OR, 1.56; 95% CI, 1.03-2.38; P &lt; 0.04), atrial flutter (OR, 2.38; 95% CI, 1.29-4.40; P &lt; 0.01), renal insufficiency (OR, 1.66; 95% CI, 1.10-3.41; P &lt; 0.03), and leg wound infection (OR, 5.34; 95% CI, 2.27-12.54; P &lt; 0.001). Obesity in diabetic patients was not independently associated with an increased risk of mortality, stroke, myocardial infarction, sepsis, or sternal wound infection.

Conclusion

Obesity in diabetic patients is an independent predictor of worsened postoperative outcomes after primary coronary artery bypass graft surgery.

QTc interval prolongation predicts postoperative mortality in heart failure patients undergoing surgical revascularization

QTc interval prolongation is associated with increased mortality rates in patients with advanced heart failure. We investigated the predictive value of prolonged QTc interval in 567 patients with heart failure who were undergoing coronary artery bypass graft surgery The patients were in New York Heart Association class III or IV, with left ventricular ejection fractions of 0.40 or less. Before surgery, the QT interval duration was measured in leads II and V4 of the standard electrocardiogram and corrected by use of the Bazett formula. The QTc interval was prolonged (>440 msec) in 243 patients (43%) and normal in 324 (57%). The 2 study groups--prolonged QTc versus normal QTc--did not differ in terms of age (62 +/- 11 years vs 64 +/- 10 years, P=0.65), sex (80% male vs 76% male, P=0.31), ejection fraction (0.29 +/- 0.08 vs 0.29 +/- 0.09, P=0.72), hypertension (82% vs 78%, P=0.34), or diabetes (11% vs 7%, P=0.10). Within 1 month after coronary artery bypass grafting, 22 of 243 patients (9.1%) in the prolonged QTc group died, compared with 5 of 324 in the normal QTc group (1.5%) (P=0.0001). QTc interval prolongation was the only independent predictor of postoperative mortality on multivariate analysis (P=0.002). We conclude that patients with heart failure and preoperative QTc interval prolongation have increased mortality rates after coronary artery bypass grafting.

Pharmacogenetics of Anesthetic and Analgesic Agents

Predicting a patient's response to a particular drug has long been a goal of clinicians. Rapid advances in molecular biology have enabled researchers to identify associations between an individual's genetic profile and drug response. Pharmacogenetics is the study of the molecular mechanisms that underlie individual differences in drug metabolism, efficacy, and side effects. The pharmacogenetics of commonly used anesthetic and analgesic agents are reviewed.

Statins are associated with a reduced incidence of perioperative mortality after coronary artery bypass graft surgery

BACKGROUND

Statin therapy in nonsurgical patient populations is associated with a significant reduction in adverse cardiovascular events, including death, myocardial infarction (MI), and stroke. Recently, statin therapy was shown to be associated with a reduced incidence of postoperative mortality in patients undergoing major noncardiac vascular surgery. We investigated the influence of preoperative statin therapy on adverse outcomes after primary coronary artery bypass graft (CABG) surgery.

METHODS AND RESULTS

A retrospective cohort study of patients undergoing primary CABG surgery with cardiopulmonary bypass (CPB) (n=1663) between January 1, 2000 and December 31, 2001 at the Texas Heart Institute was performed. Patients were classified into 2 groups: patients receiving preoperative statin therapy (n=943) and patients not receiving preoperative antihyperlipidemic therapy (n=720). To determine if preoperative statin therapy was independently associated with a reduction in the risk of adverse postoperative outcomes, multivariate stepwise logistic regression was performed controlling for patient demographics, medical history, and preoperative medications. Multivariate logistic regression analysis demonstrated that preoperative statin therapy was independently associated with a significant reduction ( approximately 50%) in the risk of 30-day all-cause mortality (3.75% versus 1.80%; P<0.05). The adjusted odds ratio for early mortality in patients receiving preoperative statin therapy compared with patients not receiving antihyperlipidemic agents was 0.53 (95% CI, 0.28 to 0.99). Statin therapy was not independently associated with a reduced risk of postoperative MI, cardiac arrhythmias, stroke, or renal dysfunction. In an attempt to further control for selection bias related to the choice of therapy, multivariate analysis of a propensity-matched cohort of 1362 patients revealed that preoperative statin therapy was independently associated with a significant reduction in the composite endpoint of 30-day all-cause mortality and stroke (7.1% versus 4.6%; P<0.05).

CONCLUSIONS

Preoperative statin therapy may reduce the risk of early mortality after primary CABG surgery with CPB.

Clopidogrel and bleeding in patients undergoing elective coronary artery bypass grafting

OBJECTIVE

In an effort to minimize transfusions in patients undergoing elective coronary artery bypass grafting operations after recent clopidogrel exposure, we studied laboratory tests predictive of platelet dysfunction and used a strict algorithm-driven treatment of bleeding.

METHODS

Forty-five patients receiving clopidogrel within 6 days of the operation and 45 control subjects were studied. Prothrombin time, activated partial thromboplastin time, platelet count, and platelet function test results were measured before heparinization, after protamine administration, and then every 2 hours. No transfusions were administered unless a patient met both laboratory and clinical criteria.

RESULTS

Algorithm-driven treatment of bleeding significantly reduced the mean units of all blood components transfused by about one third, as shown by comparison with current control and historical data. Compared with current control subjects, clopidogrel recipients required significantly more transfusions of platelets (9.0 +/- 1.7 vs 1.2 +/- 0.5 U; P <.0001) and packed red blood cells (4.3 +/- 0.6 vs 2.3 +/- 0.5 U; P =.01) and required longer periods of controlled ventilation (12.4 +/- 1.3 vs 8.6 +/- 0.8 hours; P =.02). Preoperative platelet dysfunction before heparin administration for cardiopulmonary bypass, as measured by using adenosine diphosphate aggregometry (response <40%), predicted all but 1 case of severe coagulopathy requiring multiple transfusions (16.6 +/- 2.8 U of platelets and 5.8 +/- 1.0 U of packed red blood cells).

CONCLUSIONS

A strict transfusion algorithm can reduce the transfusion requirement for all blood components. Preheparin testing of platelet function with adenosine diphosphate aggregometry can identify patients at highest risk for perioperative bleeding and transfusions and might further reduce the perioperative transfusion requirement.

Budget Negotiation for Industry-Sponsored Clinical Trials

The specialty of anesthesia is well suited to attract industry-sponsored clinical trials and research revenues because of its fundamental contributions to surgery, critical care, and pain medicine. However, the performance and budgeting of industry-sponsored clinical research over the past decade has been significantly altered by the rapid growth of commercially oriented networks of contract-research organizations and site-management organizations. Further, the competitive nature of today's clinical research climate can make the planning and negotiating of study budgets and contracts stressful, time consuming, frustrating, and full of pitfalls. Because a clinical trial contract is a fixed-price agreement, investigators are obligated to perform the work described in the contract, even if the actual costs exceed the study contract. Successful budgeting for the performance of an industry-sponsored clinical trial thus requires a thorough understanding of the direct and indirect costs associated with performing clinical research. We reviewed budget and contractual considerations for the successful negotiation and performance of industry-sponsored clinical research.

[Gene polymorphism in intensive care patients. Is the course of disease predetermined?]

Die enormen Fortschritte der molekularbiologischen Grundlagenforschung haben unser Verständnis der pathophysiologischen Mechanismen von Erkrankungen entscheidend vorangetrieben. Die große interindividuelle Variabilität von Krankheitsverläufen in der Intensivmedizin lässt sich häufig nicht allein durch bekannte Risikofaktoren erklären. Vielmehr scheint auch der Genotyp des einzelnen Patienten Inzidenz, Verlauf und Mortalität schwerster Krankheitsbilder zu verändern. Im Rahmen von Genassoziationsstudien wurde eine Vielzahl genetischer Polymorphismen untersucht, die in der Intensivmedizin eine Rolle spielen könnten. Beeinflusst werden neben Entzündungsreaktionen [z. B. Tumor-Nekrose-Faktor- (TNF-)α, Interleukin- (Il-)10] auch spezifische Infektionserkrankungen (Pneumonie, Meningitis), Sepsis oder „acute respiratory distress syndrome“ (ARDS) ebenso wie die Letalität schwerst traumatisierter Patienten [Polytrauma, Schädel-Hirn-Trauma (SHT)]. Die weitere Identifizierung solcher Allo- und Haplotypen kann nicht nur erklären, warum intensivmedizinische Patienten unterschiedlich auf vergleichbare Therapien ansprechen, sondern möglicherweise auch mittels verbesserter Risikostratifizierung und an den Genotyp des einzelnen Patienten angepasster Therapie zu einer Verringerung von Morbidität und Mortalität beitragen.

Vascular ischaemia and reperfusion injury

Although restoration of blood flow to an ischaemic organ is essential to prevent irreversible tissue injury, reperfusion per se may result in a local and systemic inflammatory response that may augment tissue injury in excess of that produced by ischaemia alone. Cellular damage after reperfusion of previously viable ischaemic tissues is defined as ischaemia-reperfusion (I-R) injury. I-R injury is characterized by oxidant production, complement activation, leucocyte-endothelial cell adhesion, platelet-leucocyte aggregation, increased microvascular permeability and decreased endothelium-dependent relaxation. In its severest form, I-R injury can lead to multiorgan dysfunction or death. Although our understanding of the pathophysiology of I-R injury has advanced significantly in the last decade, such experimentally derived concepts have yet to be fully integrated into clinical practice. Treatment of I-R injury is also confounded by the fact that inhibition of I-R-associated inflammation might disrupt protective physiological responses or result in immunosuppression. Thus, while timely reperfusion of the ischaemic area at risk remains the cornerstone of clinical practice, therapeutic strategies such as ischaemic preconditioning, controlled reperfusion, and anti-oxidant, complement or neutrophil therapy may significantly prevent or limit I-R-induced injury in humans.