Low mortality and low rate of perceived and documented arrhythmias after Cox maze III surgery for atrial fibrillation.

BACKGROUND: To report a long-term single-site experience of the cut-and-sew Cox maze III procedure for atrial fibrillation (AF). METHODS: A total of 232 consecutive patients underwent the Cox maze III procedure for symptomatic therapy-refractory AF, with concomitant surgery in 34 patients. Follow-up data were obtained from electrocardiograms, patient visits, questionnaires, and medical files. RESULTS: There were 103 patients (44%) with paroxysmal AF during 8.8 ± 6.5 years and 129 patients (56%) with nonparoxysmal AF for 7.3 ± 6.7 years. The preoperative New York Heart Association class was better in patients with paroxysmal AF (P < 0.0001); the left ventricular ejection fraction was 59 ± 7% versus 56 ± 8%, P = 0.003, and the left atrial area 24 ± 6 versus 27 ± 6 cm(2) , P = 0.01. Early and late postoperative adverse events occurred at similar rates. Four patients from each group died of reasons unrelated to surgery. The mean follow-up was 66 ± 42 (5-155) months. In total, 184/229 (80%) patients were free of documented AF/atrial flutter/atrial tachycardia (AF/AFl/AT) off antiarrhythmic drugs (AA) and 189/229 (83%) on or off AA. The hazard ratio (HR) for paroxysmal versus nonparoxysmal AF patients regarding documented AF/AFl/AT was 0.8 (95% confidence interval [CI] 0.4-1.4; P = 0.40). For patients without versus with concomitant surgery, the corresponding HR was 0.4 (95% CI 0.2-0.8; P = 0.008). Of 197 patients (89%) responding to the questionnaire, 41 had sought care for symptoms of arrhythmia, 29 of whom had documented AF/AFl/AT, whereas another six had other arrhythmias. CONCLUSION: Cut-and-sew Cox maze III surgery provided long-lasting high efficacy, also in patients with nonparoxysmal AF of long duration and/or concomitant surgery, and was associated with low rates of subsequent adverse events.

A Swedish consensus on the surgical treatment of concomitant atrial fibrillation.

Atrial fibrillation (AF) is a common arrhythmia among patients scheduled for open heart surgery and is associated with increased morbidity and mortality. According to international guidelines, symptomatic and selected asymptomatic patients should be offered concomitant surgical AF ablation in conjunction with valvular or coronary surgery. The gold standard in AF surgery is the Cox Maze III ("cut-and-sew") procedure, with surgical incisions in both atria according to a specified pattern, in order to prevent AF reentry circuits from developing. Over 90% of patients treated with the Cox Maze III procedure are free of AF after 1 year. Recent developments in ablation technology have introduced several energy sources capable of creating nonconducting atrial wall lesions. In addition, simplified lesion patterns have been suggested, but results with these techniques have been unsatisfactory. There is a clear need for standardization in AF surgery. The Swedish Arrhythmia Surgery Group, represented by surgeons from all Swedish units for cardiothoracic surgery, has therefore reached a consensus on surgical treatment of concomitant AF. This consensus emphasizes adherence to the lesion pattern in the Cox Maze III procedure and the use of biatrial lesions in nonparoxysmal AF.

Cardiac function in relation to rhythm outcome after intraoperative epicardial left atrial cryoablation.

OBJECTIVES: To assess the effects of intraoperative left atrial epicardial cryoablation on rhythm and atrial and ventricular function. DESIGN: Thirty five patients with coronary artery disease and documented atrial fibrillation underwent coronary artery bypass surgery and concomitant cryoablation. An age and gender matched control group of 35 patients with atrial fibrillation underwent bypass surgery alone. Echocardiography was performed 9 ? 32 days before and 22 ? 6 months after surgery. RESULTS: The proportion of patients in sinus rhythm at follow-up was 63% and 34% (p = 0.04) in the cryoablation and control groups, respectively. In patients with sinus rhythm both before surgery and at follow-up, the left atrial area increased (p = 0.002) and the mitral annular excursion during atrial contraction decreased (p = 0.01) after cryoablation. The mitral flow velocity during atrial systole decreased after cryoablation (p = 0.002). The LV diameter increased (p = 0.03) and the left ventricular ejection fraction (LVEF) decreased (p = 0.03) in cryoablated but not in control patients. Continued deterioration was seen in patients with atrial fibrillation both pre- and postoperatively. CONCLUSIONS: At long-term follow-up, a significantly higher proportion of patients was in sinus rhythm in the cryoablation than in the control group. The atrial and ventricular function had decreased at follow-up two years after surgery. This decrease was small and occurred within or close to the reference values in patients with sinus rhythm at follow-up, while patients remaining in atrial fibrillation showed a significant continued deterioration. Some subgroups were small, and the findings, although statistically significant, should be interpreted with caution.

Non-inferiority randomized trials, an issue between science and ethics: the case of the SYNTAX study.

Non-inferiority trials are questionable when death and serious complications are included among outcomes. The term itself "non-inferiority" is misleading, since such a study would not demonstrate that a new treatment is non-inferior to a control treatment, but simply that the inferiority would not reach a pre-specified level, deemed as acceptable by the designers of the trial. Group cross-over, assay-sensitivity and the need of a placebo arm are major issues for the reliability of non-inferiority trials. The SYNTAX trial for severe coronary artery disease was designed on a non-inferiority margin of 6.6%. In this paper we show that the SYNTAX designers were ready to accept up to 30% higher rate of death and major adverse events to claim the non-inferiority of percutaneous coronary intervention versus coronary artery bypass grafting. Eventually the SYNTAX study failed because percutaneous patients sustained an even higher rate of adverse events. We propose major caution in performing non-inferiority randomized trials.

Left ventricular diastolic function and right atrial size are important rhythm outcome predictors after intraoperative ablation for atrial fibrillation.

BACKGROUND: Left ventricular (LV) diastolic function and right atrial (RA) size are not routinely included in preoperative echocardiographic examination in patients undergoing cardiac surgery with concomitant ablation for atrial fibrillation (AF). OBJECTIVE: To investigate the role of echocardiographic variables including LV diastolic function and RA area in long-term rhythm outcome prediction, in patients with documented AF undergoing intraoperative ablation concomitant to coronary artery bypass grafting (CABG). METHODS: Thirty-five consecutive patients, scheduled for CABG, and with a history of paroxysmal or permanent AF for 8.5 ± 11.3 years (mean ± SD) (median 5.8 years), were included in this prospective study. Echocardiography was performed prior to and 2.3 ± 0.4 years after the surgical procedure. RESULTS: Both LA and RA areas, LV diastolic function, paroxysmal AF, and sinus rhythm (SR) preoperatively were associated with SR at long-term follow-up. In the multivariate analysis, RA area (P = 0.004), and decreased LV diastolic function preoperatively, measured as the maximal LV long-axis relaxation velocity (P = 0.02), predicted SR at follow-up. CONCLUSIONS: RA size and LV diastolic function may be important variables in prediction of long-term rhythm outcome after intraoperative ablation for AF.

Short-term sinus rhythm predicts long-term sinus rhythm and clinical improvement after intraoperative ablation of atrial fibrillation.

AIMS: Our aim was to compare the long-term effects on rhythm and quality of life (QoL) after left atrial epicardial radiofrequency (RF) ablation vs. no ablation in patients undergoing cardiac surgery. METHODS AND RESULTS: Thirty-nine patients with ECG documented atrial fibrillation (AF) scheduled for coronary artery bypass grafting (CABG) with or without concomitant valve surgery were consecutively elected for epicardial RF ablation. Thirty-nine age- and gender-matched patients scheduled for CABG with or without concomitant valve surgery only and with documented AF served as controls. The follow-up after ablation was 32 +/- 11 months. The percentage of patients in sinus rhythm (SR) at long-term follow-up was 62 vs. 33% (P = 0.03) after ablation and no ablation, respectively. SR at 3 months was highly predictive of that at 32 months (sensitivity 95%, positive predictive value 86%). Long-term SR was associated with better QoL, fewer symptoms, higher ejection fraction, and smaller left and right atria than AF. CONCLUSION: SR at 3 months was highly predictive of long-term SR that was associated with clinical improvement when compared with patients still in AF. AF at 3 months did not preclude a later stabilization to SR.

Microdialysis for myocardial metabolic surveillance: developing a clinical technique.

Metabolic surveillance of the myocardium is of great interest in cardiac surgery. Microdialysis allows sampling of chemical substances from the interstitial fluid for immediate analysis. The two objectives of this study were to develop a technique for simple and safe implantation of a commercially available microdialysis probe (CMA-70) into the myocardium and to obtain reference data for further use and metabolic control. Eighteen pigs were used in an experimental ischaemic heart model where the left anterior descending coronary artery was occluded for 20 min. Microdialysis was performed proximally as well as distally to the arterial occlusion site corresponding to a control and an ischaemic area in the heart. Two techniques were tried for probe implantation, using either a pacemaker wire attached to the probe tip or a needle introducer. Metabolic substrates (glucose, lactate, glycerol and pyruvate) were collected before, during and after ischaemia, for up to 6 h. Both techniques were highly effective in registering metabolic changes due to ischaemia with sharp time resolution, but the needle introducer was superior regarding probe durability. It is concluded that the CMA-70 microdialysis probe implanted with the needle introducer allows for an accurate monitoring of myocardial metabolism during a prolonged period of time. Future studies in the human heart are warranted to further validate the technique.

Angiographic results after the use of a sutureless aortic connector for proximal vein graft anastomoses.

The sutureless aortic connector system was recently developed to create anastomoses between the aorta and saphenous vein grafts for coronary artery bypass grafting. Ten consecutive patients scheduled for coronary artery bypass grafting were studied; in each patient one proximal anastomosis was performed using the aortic connector and another was sutured in the conventional manner to serve as the patient's own control. One graft in the sutured group had a significant stenosis and one of the grafts in which the aortic connector was used, was occluded. In this limited study the use of the sutureless connector system for proximal anastomosis shows satisfactory early graft patency (90%).

Early and long-term mortality in 536 patients after theCox-maze III procedure: a national registry-based study.

BACKGROUND: The cut-and-sew Cox-maze III procedure is the gold standard for surgical treatment of atrial fibrillation. The aim was to study early and long-term mortality based on registry analyses in Swedish Cox-maze III patients. METHODS: Preoperative and early postoperative data were analyzed in 536 patients (male/female (425/111), mean age 57 ± 8.6 years), operated from 1994 to 2009 in 4 centers; 422 (79%) underwent stand-alone Cox-maze III. Atrial fibrillation was paroxysmal in 38% and non-paroxysmal in 62%, mean duration was 7.8 ± 6.3 years. Patients were followed for survival or death in a validated national Cause-of-Death registry. Risk factors associated with observed survival were identified in univariable and multivariable analyses in a standard Cox proportional hazards model. RESULTS: Four early deaths (0.7%) occurred due to technical complications. At follow-up, 41 of 536 (7.6%) patients had died. Cause of death was cardiovascular in 19 of 536 (3.5%). No ischemic stroke-related death was registered. Univariable risk factors for all-cause mortality included hypertension (hazard ratio [HR] 2.8, confidence interval [CI] 1.5 to 5.3), heart failure (HR 2.4, CI 1.3 to 4.3), concomitant surgery (HR 2.2, CI 1.1 to 4.1), and postoperative complications (HR 2.5, CI 1.3 to 4.8). Gender, non-paroxysmal atrial fibrillation and long arrhythmia duration did not confer increased risk of death. Multivariable risk factors were hypertension (HR 2.9, CI 1.5 to 5.5) and postoperative complications (HR 2.4, CI 1.2 to 4.6). Survival for cardiovascular death at 5, 10, and 15 years was 98%, 96%, and 93%, respectively. CONCLUSIONS: Registry-based follow-up showed low early and long-term cardiovascular mortality and no stroke-related mortality. This is important baseline information when evaluating current surgical and nonsurgical treatment of atrial fibrillation.

Atrial function after left atrial epicardial cryoablation for atrial fibrillation in patients undergoing mitral valve surgery.

PURPOSE: To explore the effects on atrial and ventricular function of restoring sinus rhythm (SR) after epicardial cryoablation and closure of the left atrial appendage (LAA) in patients with mitral valve disease and atrial fibrillation (AF) undergoing surgery. METHODS: Sixty-five patients with permanent AF were randomized to mitral valve surgery combined with left atrial epicardial cryoablation and LAA closure (ABL group, n = 30) or to mitral valve surgery alone (control group, n = 35). Two-dimensional and Doppler echocardiography were performed before and 6 months after surgery. RESULTS: At 6 months, 73% of the patients in the ABL group and 46% of the controls were in SR. Patients in SR at 6 months had a reduction in their left ventricular diastolic diameter while the left ventricular ejection fraction was unchanged. In patients remaining in AF, the left ventricular ejection fraction was lower than at baseline. The left atrial diastolic volume was reduced after surgery, more in patients with SR than AF. In patients in SR, the peak velocity during the atrial contraction and the reservoir function were lower in the ABL group than in the control group. CONCLUSIONS: In patients in SR, signs of atrial dysfunction were observed in the ABL but not the control group. Atrial dysfunction may have existed before surgery, but the difference between the groups implies that the cryoablation procedure and/or closure of the LAA might have contributed.

Myocardial metabolism assessed by microdialysis: a prospective randomized study in on- and off-pump coronary bypass surgery.

OBJECTIVE: The aim of the study was to compare energetic metabolism in the myocardium during coronary surgery with and without cardiopulmonary bypass by means of microdialysis. METHODS: Twenty-six low-risk patients were prospectively randomized to off-pump versus on-pump surgery. Microdialysis was used to sample myocardial interstitial fluid during and for 23 hours after surgery. RESULTS: Preoperative characteristics and clinical outcome were similar in both groups. Blood glucose and lactate did not differ between groups throughout the observation time. During surgery, intramyocardial levels of glucose, pyruvate and urea were unaffected in off-pump patients, while the same substances significantly decreased (p<0.05) in on-pump patients during cardioplegic arrest, and increased during reperfusion. Interstitial lactate levels were higher during off-pump surgery (p<0.05). From 3 to 15 hours after surgery, intramyocardial concentrations of glucose, urea and lactate were higher in off-pump patients (p<0.001), while pyruvate was higher in on-pump patients (p<0.01). Intramyocardial lactate/pyruvate ratio never differed between groups. Postoperatively, cumulative blood release of troponin-T was significantly higher in the on-pump group (p<0.005). CONCLUSIONS: Microdialysis could demonstrate significant differences in energetic metabolism between the two groups. Our data confirm and might help in explaining the lower release of myocardial ischemic markers after off-pump surgery.

Surgical Ablation for Atrial Fibrillation in Cardiac Surgery: A Consensus Statement of the International Society of Minimally Invasive Cardiothoracic Surgery (ISMICS) 2009.

OBJECTIVE: : This purpose of this consensus conference was to determine whether surgical atrial fibrillation (AF) ablation during cardiac surgery improves clinical and resource outcomes compared with cardiac surgery alone in adults undergoing cardiac surgery for valve or coronary artery bypass grafting. METHODS: : Before the consensus conference, the consensus panel reviewed the best available evidence, whereby systematic reviews, randomized trials, and nonrandomized trials were considered in descending order of validity and importance. Evidence-based statements were created, and consensus processes were used to determine the ensuing recommendations. The American Heart Association/American College of Cardiology system was used to label the level of evidence and class of recommendation. RESULTS: : The consensus panel agreed on the following statements in patients with AF undergoing cardiac surgery concomitant surgical ablation: CONCLUSIONS: : Given these evidence-based statements, the consensus panel stated that, in patients with persistent and permanent AF undergoing cardiac surgery, concomitant surgical ablation is recommended to increase incidence of sinus rhythm at short- and long-term follow-up (class 1, level A); to reduce the risk of stroke and thromboembolic events (class 2a, level B); to improve EF (class 2a, level A); and to exercise tolerance (class 2a, level A) and long-term survival (class 2a, level B).

Surgical ablation for atrial fibrillation in cardiac surgery: a meta-analysis and systematic review.

OBJECTIVES: : This meta-analysis sought to determine whether surgical ablation improves clinical outcomes and resource utilization compared with no ablation in adult patients with persistent and permanent atrial fibrillation (AF) undergoing cardiac surgery. METHODS: : A comprehensive search was undertaken to identify all randomized (RCT) and nonrandomized (non-RCT) controlled trials of surgical ablation versus no ablation in patients with AF undergoing cardiac surgery up to April 2009. The primary outcome was sinus rhythm. Secondary outcomes included survival and any other reported clinically relevant outcome or indicator of resource utilization. Odds ratios (OR) and weighted mean differences (WMD) and their 95% confidence intervals (95% CI) were analyzed as appropriate using the random effects model. Heterogeneity was measured using the I statistic. Meta-regression was performed to explore the relationship between the benefit from surgical AF and duration of follow-up. RESULTS: : Thirty-three studies met the inclusion criteria (10 RCTs and 23 non-RCTs) for a total of 4647 patients. The number of patients in sinus rhythm was significantly improved at discharge in the surgical AF ablation group versus (68.6%) the surgery alone group (23.0%) in RCTs (OR 10.1, 95% CI 4.5-22.5) and non-RCTs (OR 7.15, 95% CI 3.42-14.95). This effect on sinus rhythm (74.6% vs. 18.4%) remained at follow-up of 1 to 5 years (OR 6.7, 95% CI 2.8-15.7 for RCT, and OR 15.5, 95% CI 6.6-36.7 for non-RCT). The risk of all-cause mortality at 30 days was not different between the groups in RCT (OR 1.20, 95% CI 0.52-3.16) or non-RCT studies (OR 0.99, 95% CI 0.52-1.87). In studies reporting all-cause mortality at 1 year or more (up to 5 years), mortality did not differ in RCT studies (OR 1.21, 95% CI 0.59-2.51) but was significantly reduced in non-RCT studies (OR 0.54, 95% CI 0.31-0.96). Stroke incidence was not reduced significantly; however, in meta-regression, the risk of stroke decreased significantly with longer follow-up. Other clinical outcomes were similar between groups. Operation time was significantly increased with surgical AF ablation; however, overall impact on length of stay was variable. CONCLUSIONS: : In patients with persistent or permanent AF who present for cardiac surgery, the addition of surgical AF ablation led to a significantly higher rate of sinus rhythm in RCT and non-RCT studies compared with cardiac surgery alone, and this effect remains robust over the longer term (1-5 years). Although non-RCT studies suggest the possibility of reduced risk of stroke and death, this remains to be proven in prospective RCTs with adequate power and follow-up.

Surgery for atrial fibrillation in patients with mitral valve disease: results at five years from the International Registry of Atrial Fibrillation Surgery.

OBJECTIVES: We sought to assess the clinical and survival benefit of atrial fibrillation surgery in patients submitted to mitral valve surgery after stabilization of postoperative rhythm at 1 year. METHODS: One thousand seven hundred twenty-three patients were enrolled. Patients with follow-up of longer than 1 year (n = 972) were divided into 3 groups according to surface electrocardiographic rhythm during follow-up visits: stable sinus rhythm, stable atrial fibrillation, and intermittent rhythms. Adverse cardiac event incidence and predictors of long-term outcome were compared among the 3 groups. RESULTS: In-hospital mortality was 2.6%. Risk factors for mortality were the cut-and-sew technique (odds ratio, 8.92; 95% confidence interval, 1.71-46.50; P = .009) and isolated left atrial procedure (odds ratio, 0.16; 95% confidence interval, 0.04-0.56; P = .004). At 1 year, 63.4% patients were in stable sinus rhythm. Stable sinus rhythm was found to be associated with early and late survival (P = .01, log-rank analysis). Multivariate binary logistic regression analysis found that left atrial dimension (odds ratio, 0.97; 95% confidence interval, 0.96-0.99; P = .005) and concomitant coronary revascularization (odds ratio, 0.48; 95% confidence interval, 0.25-0.92; P = .027) were independent predictors of stable sinus rhythm at 1 year after surgical intervention. At 48 months' follow-up, predictors for stable sinus rhythm were biatrial surgical approach and absence of preoperative permanent atrial fibrillation (odds ratio, 3.56; 95% confidence interval, 1.62-7.83; P < .002). Left atrial size (each millimeter) has a borderline statistical significance (odds ratio, 0.97; 95% confidence interval, 0.93-1.00; P = .065). Thromboembolic events were found to be associated with absence of stable sinus rhythm (P = .010, log-rank analysis). CONCLUSIONS: The achievement of stable sinus rhythm is a predictor of better survival and lower incidence of thromboembolic events. Predictors of stable sinus rhythm were smaller dimensions of the left atrium, biatrial approach, absence of preoperative permanent atrial fibrillation, and absence of concomitant coronary artery bypass grafting.

Health care consumption due to atrial fibrillation is markedly reduced by Maze III surgery.

BACKGROUND: Health care consumption and costs for the treatment of atrial fibrillation are high. Atrial fibrillation is effectively treated by the surgical Maze III procedure according to the Cox method. We describe the effects of this procedure on health care consumption and economy. METHODS: From October 1997 through March 2002, 72 patients underwent the Maze III procedure. Medical records of these patients were reviewed, and all data regarding hospitalization and outpatient clinic visits for atrial fibrillation and its related diseases were recorded. Accounting divisions from the contributing hospitals were consulted for the exact cost of each of these services, which were allocated into preoperative, perioperative, and postoperative periods. RESULTS: The perioperative mortality was zero. Long-term freedom from symptomatic atrial fibrillation was verified in 96% of the patients. The number of hospitalization days decreased by 84%, from 471 during the preoperative period to 79 in the postoperative (p < 0.001), and costs during the same periods decreased by 75%, from 7,075,000 Swedish Kronor to 1,757,000 Swedish Kronor (p < 0.001). CONCLUSIONS: The Maze III procedure significantly decreased the postoperative hospitalization costs in patients undergoing surgery primarily for atrial fibrillation. As well as providing an effective treatment for symptomatic arrhythmia, this procedure breaks the undesirable trend of increasing health care consumption resulting from treatment of atrial fibrillation.

A randomized double-blind study of epicardial left atrial cryoablation for permanent atrial fibrillation in patients undergoing mitral valve surgery: the SWEDish Multicentre Atrial Fibrillation study (SWEDMAF).

AIMS: The efficacy of epicardial left atrial (LA) cryoablation in eliminating atrial fibrillation (AF) in patients undergoing mitral valve surgery (MVS) is unknown. We hypothesized that MVS combined with LA cryoablation is superior to MVS alone. METHODS AND RESULTS: Sixty-nine patients with permanent AF, included at four centres, underwent MVS with or without epicardial LA cryoablation. The primary endpoint was regained sinus rhythm. Risk factors for failed AF cryoablation were elucidated. Sixty-five out of 69 patients reached the primary endpoint. At 6 and 12 months follow-up, 73.3% of patients who underwent cryoablation had regained sinus rhythm at both follow-ups, compared with 45.7 and 42.9% of patients, respectively, who underwent MVS alone (group differences, at 6 months P = 0.024, after 12 months P = 0.013). The in-hospital complication rate was 11.4% in the MVS group and 26.5% in the cryoablation group (P = 0.110). Risk factors for failed elimination of AF by cryoablation were duration of permanent AF (P = 0.012) and presence of coronary artery disease (P = 0.047), according to multiple logistic regression analysis. CONCLUSION: This first prospective randomized study showed that combining MVS with epicardial LA cryoablation is significantly better in eliminating pre-operative permanent AF than MVS alone.