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Background Although often short-lived and self-limiting, postoperative atrial fibrillation (POAF) is a well-recognized postoperative complication of cardiac surgery and is associated with a 2-fold increase in cardiovascular mortality and morbidity. Objective Our aim was to determine whether intraoperative bilateral pulmonary vein radiofrequency ablation decreases the incidence of POAF in patients undergoing coronary artery bypass grafting (CABG). Methods A total of 175 patients undergoing CABG was prospectively randomized to undergo adjuvant bilateral radiofrequency pulmonary vein ablation in addition to CABG (group A; n=89) or CABG alone (group B; n=86). Intraoperative pulmonary vein isolation was confirmed by the inability to pace the heart via the pulmonary veins after ablation. All patients received postoperative β-blocker. Results There was no difference in the incidence of POAF in the treatment group who underwent adjuvant pulmonary vein ablation (group A; 37.1%) compared with the control group who did not (group B; 36.1%) ( P = .887). There were no differences in postoperative inotropic support, antiarrhythmic drug use, need for oral anticoagulation, and complication rates. The mean length of postoperative hospital stay was 8.2 ± 6.5 days in the ablation group and 6.7 ± 4.6 days in the control group ( P Conclusion Adjuvant pulmonary vein isolation does not decrease the incidence of POAF or its clinical impact but increases the mean length of stay in the hospital. The mechanism of POAF does not appear to depend on the pulmonary veins.

Current guideline-based recommendations for oral dual-antiplatelet therapy in an acute coronary syndrome (ACS) include the use of newer adenosine diphosphate receptor inhibitor (ADPri) regimens and agents. The Canadian ACS Reflective Program is a multicenter observational quality-enhancement project that compared the use of ADPri therapy in 2 phases (November 2011-March 2013 and April 2013-November 2013) and also compared ADPri use with previous national data from the Canadian Global Registry of Acute Coronary Events (2000-2008). Of 3099 patients with ACS, 30.6% had ST-segment elevation myocardial infarction (STEMI), 52.3% had non-STEMI, and 17% had unstable angina. There was high use of dual-antiplatelet therapy for ≤ 24 hours, with important increases noted when compared with previous national experience (P for trend, < 0.0001). Clopidogrel was the most commonly used ADPri (82.2%), with lower use of the newer agents ticagrelor (9.0%) and prasugrel (3.1%). Ticagrelor and prasugrel use was most frequent in patients with STEMI undergoing percutaneous coronary intervention PCI (34.3%). There was relatively lower use of ADPri therapy at discharge; it was given mainly to patients who did not undergo PCI (68.2%) and to those with non-ST-elevation ACS (82%). When comparing the 2 consecutive phases of data collection in the ACS Reflective, there was an approximate 3- and 2-fold increase in the early and discharge use of the newer ADPri agents, respectively. In conclusion, there has been a temporal increase in ADPri use compared with previous national experience and an increased uptake of newer ADPri agents. Additional work is needed to identify and address barriers limiting optimal implementation of these newer guideline-recommended agents into routine Canadian practice.

Introduction: Ascertaining the biological age of patients with advanced vascular disease could advance risk assessment and management. The extent to which telomeres shorten in leukocytes could be a marker of biological age because it reflects the accumulation of replication stresses imposed on leukocyte progenitors. However, because of wide, genetic variability in leukocyte telomere length (TL), a single leukocyte TL measurement does not reliably indicate telomere shortening. Hypothesis: We hypothesized that the difference in length of telomeres in “non-replicating” muscle-rich tissue and that of circulating leukocytes provides a patient-specific index of telomere shortening in patients with advanced vascular disease. Methods: TL in leukocytes, skeletal muscle, and right atrial cardiac muscle were measured from 134 patients undergoing coronary or thoracic aortic surgery, using quantitative polymerase chain reaction. Relationships between leukocyte TL or the muscle-leukocyte TL difference (ΔTL) and early post-operative outcomes were tested using Cox proportional hazard and binary logistic regression analyses. Results: Telomeres in cardiac muscle and skeletal muscle were significantly longer than those in leukocytes (p Conclusions: Right atrium-leukocyte ΔTL provides an index of telomere shortening and may inform outcomes in patients with advanced vascular disease. This two-component telomere measurement may reflect the biological age of individuals with chronic vascular disease.

Background Randomized trials have established the efficacy of clopidogrel in acute coronary syndromes (ACS). The benefit of clopidogrel has also been observed in the subgroup of ACS patients who subsequently undergo coronary artery bypass surgery (CABG); however, this therapy is discontinued preoperatively and the frequency with which clopidogrel is restarted post-CABG is unknown. Methods We examined the pattern of clopidogrel use in the Canadian Global Registry of Acute Coronary Events (GRACE), GRACE2, and CANRACE (2003-2008) post-CABG ACS patients. We stratified the patients according to whether they underwent CABG during their index hospitalization for ACS and whether they were prescribed clopidogrel at discharge. Results Among those patients in whom clopidogrel status at discharge was known, 5904 (60%) of 9841 were discharged from hospital on clopidogrel. Use of clopidogrel at discharge was observed in 2222 (40.8%) of 5443 patients who were medically managed (ie, did not undergo percutaneous coronary intervention [PCI] or CABG) and in 3585 (90.1%) of 3980 patients who underwent in-hospital PCI. Overall, 455 (3.3%) of 13,776 patients underwent CABG during the index hospitalization; 255 (56%) patients were started on clopidogrel during the first 24 hours, and 66 of these patients (25.9%) were discharged on clopidogrel. In contrast, 5681 (61.3%) of the 9262 patients who did not undergo in-hospital CABG were discharged on clopidogrel. Conclusions Although current guidelines recommend the use of clopidogrel post-CABG in patients with ACS, our observations suggest that only 1 in 4 or 5 Canadian patients are discharged on this therapy.

We present a case of a 48-year-old female patient successfully bridged to recovery with the Impella 5.0 microaxial pump (Abiomed, Danvers, MA USA) after presenting with cardiogenic shock secondary to acute fulminant viral myocarditis. After 1 week of flu-like symptoms, the patient presented to her community emergency department with chest pain and hypotension. A diagnosis of inferior ST elevation myocardial infarction was made; subsequent angiography demonstrated normal coronary arteries and a left ventricular ejection fraction of 10%. A provisional diagnosis of viral myocarditis was made. As her condition deteriorated further, she underwent insertion of an Impella 5.0 after failure of supportive medical therapy. Myocardial recovery occurred, and the Impella was removed after 1 week. After a prolonged cardiac intensive care unit stay requiring temporary hemodialysis, the patient recovered sufficiently to tolerate device explant, transfer to the recovery ward, and ultimate discharge home. This case report highlights the benefit of mechanical circulatory support in a patient with cardiogenic shock from viral myocarditis as well as some of the complications that can occur in this critically ill subset of patients.

Background Off-pump coronary artery bypass (OPCAB) surgery has been successfully used in diverse patient populations and has been postulated to be safer than conventional coronary artery bypass (CCAB) surgery in some high-risk patients, including the elderly. Objective To compare the safety of OPCAB surgery versus CCAB surgery in the octogenarian population of two large southwestern Ontario cardiac surgical units. Results Two hundred thirty-six consecutive octogenarians underwent primary isolated coronary artery bypass sugery from November 2000 to March 2005. Patients undergoing OPCAB surgery tended to have higher Parsonnet scores, while patients undergoing CCAB surgery had a greater number of emergent operations. The Canadian Cardiovascular Network predicted that mortality risk was similar in both groups. In-hospital mortality was similar between groups, as was postoperative myocardial infarction and new onset of renal dysfunction. However, in the OPCAB group, there was a decreased incidence of postoperative neurological dysfunction (2.3% in the OPCAB group versus 10.5% in the CCAB group, P=0.01), in particular cerebrovascular accidents (1.5% in the OPCAB group versus 7.6% in the CCAB group, P=0.05), and a decreased incidence of prolonged intubation (5.3% in the OPCAB group versus 13.3% in the CCAB group, P=0.04). Multivariable analysis found that cardiopulmonary bypass had no significant impact on mortality or length of stay. Conclusions In octogenarian patients, OPCAB surgery is as safe as CCAB surgery in terms of mortality and major morbidity. Furthermore, a significant reduction in neurological dysfunction and prolonged intubation was seen in the OPCAB group compared with the CCAB group.

Clopidogrel (Plavix) is a potent inhibitor of platelet aggregation used concomitantly with percutaneous coronary interventions and in patients with acute coronary syndromes. Its favorable effects on preventing thrombus formation may have deleterious effects on hemostasis in patients undergoing coronary surgery.Data were collected prospectively on 312 consecutive urgent or emergent coronary artery bypass patients from July 1999 through April 2001 at a tertiary care center. Patients were stratified into three groups: clopidogrel within 4 days of operation (n = 41), clopidogrel continued until 5 to 8 days before operation (n = 39), and clopidogrel discontinued more than 8 days before operation or were never taking clopidogrel (n = 232).Preoperative and intraoperative characteristics were similar among all groups. Mediastinal and pericardial chest tube losses in the first 24 hours were 1,044 +/- 750 mL in the clopidogrel within 4 days group, 528 +/- 250 mL in the clopidogrel 5 to 8 days group, and 573 +/- 329 mL in the clopidogrel more than 8 days group (p0.01). The mean total blood product transfusions were 12.2 +/- 15.4 U, 1.2 +/- 2.0 U, and 2.6 +/- 5.7 U, respectively (p0.001). Reoperation for bleeding was noted in 14.6%, 2.6%, and 1.7%, respectively (p = 0.002). The median hospital lengths of stay for the three groups were 9 days, 7 days, and 7 days, respectively (p = 0.018). There were no statistically significant differences in mortality rate, myocardial infarction, stroke, mediastinitis, or postoperative renal failure among the groups. Multivariable analysis revealed that clopidogrel within 0 to 4 days of operation was an independent predictor of transfusion requirements (OR 4.22, 95% confidence interval [CI] 2.07, 9.34, p = 0.001), intensive care unit (ICU) length of stay (OR 3.14, 95% CI 1.40, 7.04, p = 0.006), and total hospital length of stay (coefficient 7.65, se 2.41, p = 0.002).Clopidogrel within 4 days of coronary bypass surgery is associated with increased blood losses and reoperation for bleeding and, according to multivariable models, is an independent risk factor for increased transfusion requirements and prolonged ICU and hospital length of stay.

Background Pulmonary function testing is an integral part of evaluating patients who are being considered for cardiac transplantation. The accurate measurement of diffusing capacity (D lco ) and alveolar volume (VA) is dependent on a 10-s breath-holding maneuver that may be difficult for patients with congestive heart failure to perform. The intrabreath (IB) technique is not dependent on a breath-holding maneuver and may provide more accurate pulmonary function testing results in chronically debilitated patients. Methods Seventy-five patients performed maneuvers with IB and single-breath (SB) techniques during evaluation for heart transplantation and at 3 and 12 months following transplantation. The D lco , VA, and total lung capacity (TLC) were compared using Pearson correlation coefficients, a Student t test, and intercorrelation coefficients. Results The D lco and VA, when determined with the IB technique, had excellent correlations to the SB technique over all ranges of D lco values. VA values that were determined by the IB technique were greater than those determined by the SB technique and more closely approximated the TLC values. The satisfactory correlation between the two techniques was maintained when D lco was corrected for VA. However, due to the lower values for VA as determined by the SB method, the corrected measurements were consistently higher for the SB technique. Conclusion Pulmonary function can be measured accurately in a population of patients with long-standing congestive heart failure, both before and after cardiac transplantation, using the IB technique. Furthermore, the IB technique may provide a more accurate measurement of VA.

Background and Aim: We have shown that cumulative sum (CUSUM) failure analysis may be more sensitive than standard statistical methods in detecting a cluster of adverse patient outcomes after cardiac surgical procedures. We therefore applied CUSUM, as well as standard statistical techniques, to analyze a surgeon's experience with off-pump coronary artery bypass grafting (OPCAB) and on-pump procedures to determine whether the two techniques have similar or different outcomes. Methods: In 320 patients undergoing nonemergent, first time coronary artery bypass grafting, preoperative patient characteristics, rates of mortality and major complications, and ICU and hospital lengths of stay were compared between the on-pump and OPCAB cohorts using Fisher's exact tests and Wilcoxon two sample tests. Predicted mortality and length of stay were determined using previously validated models of the Cardiac Care Network of Ontario. Observed versus expected ratios of both variables were calculated for the two types of procedures. Furthermore, CUSUM curves were constructed for the on-pump and OPCAB cohorts. A multivariable analysis of the predictors of hospital length of stay was also performed to determine whether the type of coronary artery bypass procedure had an independent impact on this variable. Results: The predicted mortality risk and predicted hospital length of stay were almost identical in the 208 on-pump patients ( 2.2 ± 3.9% ; 8.2 ± 2.5 days) and the 112 OPCAB patients ( 2.0 ± 2.2% ; 7.8 ± 2.1 days). The incidence of hospital mortality and postoperative stroke were 2.9% and 2.4% in on-pump patients versus zero in OPCAB patients (p= 0.09 and 0.17, respectively). Mechanical ventilation for greater than 48 hours was significantly less common in OPCAB (1.8%) than in on-pump patients (7.7%, p= 0.04). The rate of 10 major complications was 14.9% in on-pump versus 8.0% in OPCAB patients (p= 0.08). OPCAB patients experienced a hospital length of stay that was a median of 1.0 day shorter than on-pump patients (p= 0.01). The observed versus expected ratio for length of stay was 0.78 in OPCAB patients versus 0.95 in on-pump patients. On CUSUM analysis, the failure curve in OPCAB patients was negative and was flatter than that of on-pump patients throughout the duration of the study. Furthermore, OPCAB was an independent predictor of a reduced hospital length of stay on multivariable analysis. Conclusions: OPCAB was associated with better outcomes than on-pump coronary artery bypass despite a similar predicted risk. This robust finding was documented on sensitive CUSUM analysis, using standard statistical techniques and on a multivariable analysis of the independent predictors of hospital length of stay.(J Card Surg 2002;17:520-528)

Introduction Steroids In caRdiac Surgery trial (SIRS) is a large international randomised controlled trial of methylprednisolone or placebo in patients undergoing cardiac surgery with the use of a cardiopulmonary bypass pump. At the time of surgery, compared with placebo, methylprednisolone divided into two intravenous doses of 250 mg each may reduce the risk of postoperative acute kidney injury (AKI). Methods and analysis With respect to the study schedule, over 7000 substudy eligible patients from 81 centres in 18 countries were randomised in December 2013. The authors will use a logistic regression to estimate the adjusted OR of methylprednisolone versus placebo on the primary outcome of AKI in the 14 days following surgery (a postoperative increase in serum creatinine of ≥50%, or ≥26.5 μmol/L, from the preoperative value). The stage of AKI will also be considered, as will the outcome of AKI in those with and without preoperative chronic kidney disease. After receipt of grant funding, the authors began to record additional perioperative serum creatinine measurements in consecutive patients enrolled at substudy participating centres, and patients were invited to enroll in a 6-month serum creatinine collection. In these trial subpopulations, the authors will consider the outcome of AKI defined in alternate ways, and the outcome of a 6-month change in kidney function from the preoperative value. Ethics and dissemination The authors were competitively awarded a grant from the Canadian Institutes of Health Research for this SIRS AKI substudy. Ethics approval was obtained for additional serum creatinine recordings in consecutive patients enrolled at participating centres. The additional kidney data collection first began for patients enrolled after 1 March 2012. In patients who provided consent, the last 6-month kidney outcome data will be collected in 2014. The results will be reported no later than 2015. Clinical Trial Registration Number NCT00427388.

Background and Objective: Human leukocyte antigen (HLA) compatibility has been shown to improve the outcome of renal and cardiac transplantation. However, its impact on outcome following lung transplantation is not clear, with several single-center studies reporting inconsistent results. We studied the influence of HLA matching on survival and the development of rejection and obliterative bronchiolitis after lung transplantation, using data from the United Network for Organ Sharing/International Society for Heart and Lung Transplantation registry. Methods The study population included adult patients who received cadaveric lung transplants between October 1987 and June 1997 for whom HLA data were available. Two cohorts were examined, depending on the era of transplantation: (1) October 1987 to June 1997 ( n = 3,549): Differences in actuarial survival as stratified by either the total number of HLA mismatches or the number of mismatches at each HLA locus were determined using a log-rank test. Multivariate logistic regression models were developed to determine independent predictors of survival at 1, 3, and 5 years following lung transplantation. (2) April 1994 to June 1997 ( n = 1,796): The association of HLA mismatching with acute rejection and obliterative bronchiolitis was determined using a chi-squared analysis. Results Only 164 patients (4.6%) received lung grafts with 2 or fewer HLA mismatches. Univariate analyses demonstrated a significant difference in post-transplant survival by mismatch level, with the total number of HLA mismatches ( p = 0.0008) and mismatching at the HLA-A locus ( p = 0.002) associated with worse survival. Multivariate logistic regression demonstrated that the number of mismatches at the HLA-A and HLA-DR loci predicted 1-year mortality (incremental odds ratios 1.18, p = 0.01, and 1.15, p = 0.03, respectively). The total number of HLA mismatches predicted 3- and 5-year mortality (incremental odds ratios 1.13 at 3 years, p = 0.0004, and 1.14 at 5 years, p = 0.0002). However, other covariates such as repeat transplantation, transplantation for congenital heart disease, advanced recipient age, and an early era of transplantation were stronger predictors of mortality. We found no significant association between HLA mismatching and the development of obliterative bronchiolitis, although there was an association between mismatching at the HLA-A locus and acute rejection episodes requiring hospital admission ( p = 0.008). We also found no association between mismatching at the HLA-B locus and rejection episodes requiring either hospitalization or the alteration of anti-rejection medications ( p = 0.034). Conclusion Although the number of HLA mismatches at the HLA-A and HLA-DR loci predicted 1-year mortality and the total number of mismatches predicted 3- and 5-year mortality following lung transplantation, the effect of each covariate was small in this multicenter study of 3,549 patients. Further close follow-up of registry patients is necessary to determine the effect of HLA matching on long-term survival and freedom from obliterative bronchiolitis and rejection following lung transplantation. A prospective study of HLA matching for lung transplantation should not yet be considered in view of the small number of grafts with 2 or fewer mismatches and the modest effect of HLA matching on outcome.

Objective To compare measurements obtained by transesophageal echocardiography (TEE) and epicardial echocardiography (EE) for evaluation of the tricuspid valve (TV) and pulmonary valve (PV). Design Prospective observational. Setting University hospital. Participants Patients undergoing elective coronary artery bypass grafting with or without aortic valve replacement. Interventions After routine intraoperative TEE, EE was performed to compare measurements obtained by the 2 methods. Measurements and main results After institutional review board approval, 25 patients >18 years old were recruited. Biases with EE versus TEE for E and A waves were 11.9 cm/second (95% confidence interval [CI], 48.2 to −24.4) and 6.8 cm/second (95% CI, 28 to −15), respectively, and for E/A ratio was 0.08 (95% CI, 1.2 to −1). Pulmonary velocity bias was 57.94 cm/second (95% CI, 192.9 to −76.98), with higher values using EE. Bias for pulmonary trunk diameter was −0.31 cm (95% CI, 1.5 to −2.1). For quality of images, means were 2.4 (standard deviation [SD], 1.0) for EE and 2.3 (SD, 0.57) with TEE for TV and 2.4 (SD, 1.0) with EE and 2.5 (SD, 1.0) with TEE for PV. For the number of leaflets visualized, means were 2.2 (SD, 1.0) with EE and 2.5 (SD, 0.5) with TEE for TV and 2.5 (SD, 0.5) for EE and 1.3 (SD, 1.1) with TEE for PV. Conclusions There was good agreement for Doppler measurements across TVs; however, measurements across PVs were significantly higher with EE versus TEE. TV Doppler measurements were difficult to acquire even for surgeons experienced in epiaortic scanning.

Objective The purpose of this study was to compare transvalvular flow velocities obtained by transesophageal echocardiography and epicardial echocardiography (EE) during aortic valve replacement (AVR). Design Prospective observational study. Setting University hospital. Participants Patients undergoing AVR for aortic stenosis. Interventions After institutional review board approval, 17 patients undergoing AVR consented. Deep transgastric (deep TG LAX) and transgastric long-axis (TG LAX) views and epicardial aortic valve long-axis views (S8 probe) were obtained on a SONOS 5500 (Phillips Medical Systems, Bothell, WA) before and after AVR. Transvalvular flow velocity and velocity time integral (VTI) were recorded via each technique. Measurements were made offline by 2 independent reviewers. Agreement between measurements made by different views was evaluated by using Bland-Altman analysis. Measurements and Main Results The epicardial probe was well tolerated. Quality images were obtained in all patients with TEE and 30 of 34 studies via epicardial scanning. The mean bias for peak velocities derived through EE and deep TG LAX was 96.3 cm/s (95% confidence interval [CI], 51.1-141.4) before AVR and 58 cm/s (95% CI, 32.4-83.7) after AVR. The mean bias for peak velocities between EE and TG LAX was 70 cm/s (95% CI, 31.1-108.9) before and 84.7 cm/s (95% CI, 55.6-113.7) after AVR. Similar results were obtained for VTI. Conclusions Peak transaortic valve velocities and VTI measured with epicardial echocardiography are higher in comparison to measurements via TEE in patients undergoing AVR. The precise role of epicardial echocardiography in the comprehensive echocardiographic examination of patients undergoing aortic valve replacement needs further evaluation.

Background Serial measurements of pulmonary function to indicate decreasing respiratory muscle strength in patients with amyotrophic lateral sclerosis (ALS) is well documented. Quantitative outcome measures include declining FVC, FEV1, maximal inspired pressure, maximal expired pressure, and maximal voluntary ventilation. Increasing peak expiratory flow time (PEFT) may represent a further sensitive measure of declining respiratory muscle strength in ALS. Methods Fifty-five patients with ALS performed flow-volume loops serially after presentation. The percentage change from baseline values for FVC, peak expiratory flow (PEFR), and PEFT were compared using Spearman correlation coefficients. The prolongation of PEFT with serial tests was analyzed using a Kruskal-Wallis with a Dunn multiple comparison test. Bulbar-onset and limb-onset PEFT was compared using the Mann-Whitney test. Results PEFT was significantly increased from baseline values at all follow-up tests. However, PEFTs measured at the third, fourth, fifth, and sixth visits, although higher, were not significantly different. Significant negative correlations existed between the increase in PEFT and the decrease in PEFR and FVC. Significant positive correlations existed between the increase in PEFT and days from diagnosis and the decrease in PEFR and decrease in FVC. Conclusion PEFT increases significantly and linearly with time in patients with ALS and may begin to plateau with bulbar symptoms. PEFT increases at a faster rate than the rate of decline in both FVC and PEFR. PEFT is a quantitative measure of decreasing pulmonary function in ALS that is easily measured.

The purpose of these experiments was to determine the frequency dependence of the effects of amiodarone and its active desethyl metabolite on slow-channel tissues. Intravenous amiodarone and desethylamiodarone (10 or 25 mg/kg) increased atrioventricular conduction time (AVCT) and refractory period (AVERP) in open-chest, chloralose-anesthetized dogs. Drug effects on AVCT and AVERP were greatly augmented by increasing atrial stimulation frequency. The frequency dependence of drug effects was quantified by studying the response of atrioventricular (AV) conduction to changes in coupling interval. Under control conditions, premature atrial stimulation increased AVCT with a time constant of 70 msec. In the presence of amiodarone and desethylamiodarone, a biexponential relationship between AVCT and coupling interval was observed. One component had a time constant similar to control, and a slower component with a time constant of about 1 sec appeared. Slow-channel action potentials produced in canine cardiac false tendons by elevated potassium (25 mM) and isoproterenol in vitro showed interval-dependent changes in Vmax with a time constant averaging 74 msec in the absence of amiodarone. In the presence of amiodarone, a slower recovery phase of Vmax with a time constant averaging 0.94 sec was observed. These results indicate that amiodarone and its metabolite produce heart rate-dependent changes in AV nodal function in vivo and suggest use-dependent calcium-channel blockade as a mechanism of this action. Amiodarone's rate-related effects on slow-channel properties should produce selective depression of supraventricular tachyarrhythmias involving rapid activation of the AV node.