Ashleigh Xie

Surgical ablation for treatment of atrial fibrillation in cardiac surgery: a cumulative meta-analysis of randomised controlled trials

Introduction Concomitant surgical ablation is a treatment modality for patients with atrial fibrillation (AF) undergoing cardiac surgery, however, its efficacy and clinical outcomes are not well established. The present study is the first cumulative meta-analysis of randomised controlled trials (RCT) on clinical outcomes of surgical ablation versus no ablative treatment in all patients with cardiac surgery. Methods Electronic searches were performed using six databases from their inception to October 2013, identifying all relevant RCTs comparing surgical ablation versus no ablation in patients with AF undertaking cardiac surgery. Data were extracted and analysed according to predefined clinical endpoints. Results Sixteen relevant RCTs were identified for the present study. Higher prevalence of sinus rhythm in the surgical ablation group was evident at all ≥12 month follow-up (OR, 6.72; 95% CI 4.88 to 9.25; p<0.00001). There were no significant differences between surgical ablation versus no ablation in terms of mortality (OR, 1.05; 95% CI 0.66 to 1.68; p=0.83), pacemaker implantations (OR, 0.88; 95% CI 0.51 to 1.51; p=0.64), and neurological events (OR, 0.86; 95% CI 0.37 to 2.04; p=0.74). Cumulative meta-analysis demonstrated that these trends have remained consistent over the years, with recent studies narrowing the CIs of the summary estimates. Conclusions The evaluation of the current randomised trials demonstrates that concomitant surgical ablation and cardiac surgery is safe and effective at restoring sinus rhythm.

Venoarterial Extracorporeal Membrane Oxygenation for Cardiogenic Shock and Cardiac Arrest: A Meta-Analysis

OBJECTIVE To evaluate the effect of extracorporeal membrane oxygenation (ECMO) on survival and complication rates in adults with refractory cardiogenic shock or cardiac arrest. DESIGN Meta-analysis. SETTING University hospitals. PARTICIPANTS One thousand one hundred ninety-nine patients from 22 observational studies. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Observational studies published from the year 2000 onwards, examining at least 10 adult patients who received ECMO for refractory cardiogenic shock or cardiac arrest were included. Pooled estimates with 95% confidence intervals were calculated based on the Freeman-Tukey double-arcsine transformation and DerSimonian-Laird random-effect model. Survival to discharge was 40.2% (95% confidence intervals [CI], 33.9-46.7), while survival at 3, 6, and 12 months was 55.9% (95% CI, 41.5-69.8), 47.6% (95% CI, 25.4-70.2), and 54.4% (95% CI, 36.6-71.7), respectively. Survival up to 30 days was higher in cardiogenic shock patients (52.5%, 95% CI, 43.7%-61.2%) compared to cardiac arrest (36.2%, 95% CI, 23.1%-50.4%). Concurrently, complication rates were particularly substantial for neurologic deficits (13.3%, 95% CI, 8.3-19.3), infection (25.1%, 95%CI, 15.9-35.5), and renal impairment (47.4%, 95% CI, 30.2-64.9). Significant heterogeneity was detected, although its levels were similar to previous meta-analyses that only examined short-term survival to discharge. CONCLUSIONS Venoarterial ECMO can improve short-term survival in adults with refractory cardiogenic shock or cardiac arrest. It also may provide favorable long-term survival at up to 3 years postdischarge. However, ECMO also is associated with significant complication rates, which must be incorporated into the risk-benefit analysis when considering treatment. These findings require confirmation by large, adequately controlled and standardized trials with long-term follow-up.

Systematic review and meta-analysis of surgical ablation for atrial fibrillation during mitral valve surgery.

BACKGROUND Surgical ablation has emerged as an acceptable treatment modality for patients with atrial fibrillation (AF) undertaking concomitant cardiac surgery. However, the efficacy of surgical ablation in patient populations undergoing mitral valve surgery is not well established. The present meta-analysis aims to establish the current randomized evidence on clinical outcomes of surgical ablation versus no ablative treatment in patients with AF undergoing mitral valve surgery. METHODS Electronic searches were performed using six databases from their inception to September 2013, identifying all relevant randomized controlled trials (RCTs) comparing surgical ablation versus no ablation in AF patients undergoing mitral valve surgery. Data were extracted and analyzed according to predefined clinical endpoints. RESULTS Nine relevant RCTs were identified for inclusion in the present analysis. The number of patients in sinus rhythm (SR) was significantly improved in the surgical ablation group compared to the non-ablation group at discharge. This effect on SR remained at all follow-up periods until >1 year. Results indicated that there was no significant difference between surgical ablation and no ablation in terms of 30-day mortality, all-cause mortality, pacemaker implantation, stroke, thromboembolism, cardiac tamponade, reoperation for bleeding and myocardial infarction. CONCLUSIONS Results from the present meta-analysis demonstrate that the addition of surgical ablation for AF leads to a significantly higher rate of sinus rhythm in mitral valve surgical patients, with no increase in the rates of mortality, pacemaker implantation, stroke and thromboembolism. Further research should be directed at correlating different surgical ablation subtypes to cardiac and cerebrovascular events at long-term follow-up.

Ministernotomy or minithoracotomy for minimally invasive aortic valve replacement: a Bayesian network meta-analysis

BACKGROUND Establishing the relative merits of ministernotomy (MS) and minithoracotomy (MT) approaches to minimally invasive aortic valve replacement (MIAVR) is difficult given the limited available direct evidence. Network meta-analysis is a Bayesian approach that can combine direct and indirect evidence to better define the benefits and risks of MS and MT. METHODS Electronic searches were performed using six databases from their inception to June 2014. Relevant studies utilizing a minimally invasive approach for aortic valve replacement were identified. Data were extracted and analyzed according to predefined clinical endpoints. Both traditional and Bayesian meta-analysis approaches were conducted. RESULTS Compared to full sternotomy, MT was associated with longer cardiopulmonary bypass (CPB) duration (WMD, 9.99; 95% CI, 3.91, 16.07; I(2)=55%; P=0.001) and cross-clamp duration (WMD, 7.64; 95% CI, 2.86, 12.42; P=0.002; I(2)=74%). When compared to MS using network meta-analysis, no significant difference in duration was detected. Postoperative outcomes including 30-day mortality, stroke, and reoperation for bleeding and wound infection were comparable between MS and MT using both traditional and Bayesian meta-analysis techniques. CONCLUSIONS The current evidence demonstrates that MIAVR via MS or MT is a safe and efficacious alternative to conventional median sternotomy. MT may be associated with longer CPB and cross-clamp durations, but has similar post-operative outcomes compared to MS. An individualized approach tailored to both the patient and surgical team is likely to provide optimal outcomes.

Biatrial ablation vs. left atrial concomitant surgical ablation for treatment of atrial fibrillation: a meta-analysis

AIMS Surgical ablation performed concomitantly with cardiac surgery has emerged as an effective curative strategy for atrial fibrillation (AF). Left atrial (LA) lesion sets for ablation have been suggested to reduce procedural times and post-surgical bradycardia compared with biatrial (BA) lesions. Given the inconclusive literature regarding BA vs. LA ablation, the present meta-analysis sought to assess the current evidence. METHODS AND RESULTS Electronic searches were performed using six databases from their inception to December 2013, identifying all relevant randomized trials and observational studies comparing BA vs. LA surgical ablation AF patients undertaking cardiac surgery. In 10 included studies, 2225 patient results were available for analysis to compare BA (n = 888) vs. LA (n = 1337) ablation. Sinus rhythm prevalence was higher in the BA cohort compared with the LA cohort at 6-month and 12-month follow-up, but similar beyond 1 year. Permanent pacemaker implantations were higher in the BA cohort, but 30-day and late mortality, neurological events, and reoperation for bleeding were similar between BA and LA groups. CONCLUSIONS Biatrial and LA ablations produced comparable 30-day and late mortality but LA was associated with significantly reduced permanent pacemaker implantation rates. Biatrial ablation appeared to be more efficacious than LA ablation in achieving SR at 1 year, but this difference was not maintained beyond 1 year. Trends appear to be driven by the preferential selection of long-standing and persistent AF patients for the BA approach. Future randomized studies of adequate follow-up are required to validate risks and benefits of BA vs. LA surgical ablation.

Durability of continuous-flow left ventricular assist devices: a systematic review

BACKGROUND Left ventricular assist devices (LVADs) are becoming an increasingly viable alternative therapy for heart failure, either as a bridge to heart transplantation (BTT) or destination therapy (DT). The latter has become increasingly popular in recent years, in the face of a donor organ shortage and a rise in elderly patients ineligible for heart transplants. For these patients in particular, device durability is a key contributor to survival, morbidity, and quality of life. This systematic review aimed to assess the long-term durability of current continuous-flow LVADs. METHODS Six electronic databases were searched from their dates of inception to August 2014 for original studies reporting on patients receiving continuous-flow LVADs. LVAD failure was defined as device malfunction necessitating exchange or explantation, or causing patient mortality. Pooled averages were calculated for outcomes and rates of device failure were reconstructed from digitized graph curves using the software, WebPlotDigitizer v3.3. RESULTS Twelve retrospective observational studies with a total of 5,471 patients were included for analysis. The mean duration of LVAD support was 504.7 (range, 303-568) days, and the overall weighted incidence of device failure was 3.9% (range, 1-11.3%). On average, pump thrombosis was the most common cause of device failure (50.5%), followed by lead or cable damage (21.7%), mechanical pump failure (11.6%), device-related infection (11.1%), and surgical complications from implantation (2.5%). Long-term device failure rates at 2-, 6-, 12-, 18- and 24-months post-implantation were 0.5%, 1.8%, 2.9%, 4.5% and 6.5%, respectively. CONCLUSIONS With the expected rise in LVAD usage for end-stage heart failure, particularly as a DT, the steady minority of patients experiencing device failure is likely to increase. Further investigation is required into the incidence and mechanism of major causes of failure, as well as design improvements that may address these complications. There is currently a lack of guidelines and large randomized studies reporting on the etiology and outcomes of LVAD failure.

Comparing energy sources for surgical ablation of atrial fibrillation: a Bayesian network meta-analysis of randomized, controlled trials

Simplified maze procedures involving radiofrequency, cryoenergy and microwave energy sources have been increasingly utilized for surgical treatment of atrial fibrillation as an alternative to the traditional cut-and-sew approach. In the absence of direct comparisons, a Bayesian network meta-analysis is another alternative to assess the relative effect of different treatments, using indirect evidence. A Bayesian meta-analysis of indirect evidence was performed using 16 published randomized trials identified from 6 databases. Rank probability analysis was used to rank each intervention in terms of their probability of having the best outcome. Sinus rhythm prevalence beyond the 12-month follow-up was similar between the cut-and-sew, microwave and radiofrequency approaches, which were all ranked better than cryoablation (respectively, 39, 36, and 25 vs 1%). The cut-and-sew maze was ranked worst in terms of mortality outcomes compared with microwave, radiofrequency and cryoenergy (2 vs 19, 34, and 24%, respectively). The cut-and-sew maze procedure was associated with significantly lower stroke rates compared with microwave ablation [odds ratio <0.01; 95% confidence interval 0.00, 0.82], and ranked the best in terms of pacemaker requirements compared with microwave, radiofrequency and cryoenergy (81 vs 14, and 1, <0.01% respectively). Bayesian rank probability analysis shows that the cut-and-sew approach is associated with the best outcomes in terms of sinus rhythm prevalence and stroke outcomes, and remains the gold standard approach for AF treatment. Given the limitations of indirect comparison analysis, these results should be viewed with caution and not over-interpreted.

Video-assisted thoracoscopic surgery versus open thymectomy for thymoma: a systematic review

BACKGROUND Video-assisted thoracoscopic surgery (VATS) thymectomy is an increasingly utilized alternative to traditional open approaches for the resection of thymomas. Recent studies have suggested comparable survival and oncological efficacy as well as reduced perioperative morbidity when using the VATS approach. This current systematic review thus aimed to critically evaluate existing evidence for the efficacy and safety of VATS versus open (transsternal or transthoracic) thymectomy for thymomas. METHODS Six electronic databases were searched from their date of inception to April 2015. Relevant studies were identified using specific eligibility criteria and data were extracted and analyzed based on predefined primary and secondary endpoints. RESULTS Fourteen comparative observational studies with a total of 1,061 patients were obtained for qualitative assessment, data extraction and analysis. Five-year overall survival and 10-year recurrence-free survival was similar or higher in patients undergoing VATS compared to open thymectomy. On average, the VATS group also demonstrated reduced intraoperative blood loss (131.8 vs. 340.5 mL), shorter hospital stays (7.0 vs. 9.8 days), and lower rates of postoperative pneumonia (1.9% vs. 4.1%). The mean rate of conversion from VATS to open thymectomy was relatively low (3.1%), while 30-day mortality remained low in both the VATS and open groups (0 vs. 0.3%). CONCLUSIONS The current evidence suggests that VATS thymectomy for thymoma has at least equal if not superior oncological efficacy and survival outcomes, as well as reduced perioperative complications, compared to open surgery. Further adequately powered studies and future randomized trials are required to confirm these findings.

Neurologic Complications of Extracorporeal Membrane Oxygenation: A Review

OBJECTIVE To review the evidence on neurologic complications in adult extracorporeal membrane oxygenation (ECMO) patients with regard to incidence, pathophysiology, risk factors, diagnosis, monitoring techniques, prevention, and management. DESIGN Literature review. SETTING Observational studies and case reports from a variety of institutions. PARTICIPANTS Adult ECMO patients. INTERVENTIONS Six electronic databases were searched from their dates of inception to October 2016. MEASUREMENTS AND MAIN RESULTS The range of neurologic complications reported in adult ECMO patients included stroke, intracranial hemorrhage, and brain death. Due to a lack of standardized reporting, their true incidence may have been underestimated significantly. A variety of pathophysiologic mechanisms and risk factors have been proposed. Some of these are specific to venoarterial ECMO, whereas others may be more relevant to venovenous ECMO (eg, rapid correction of hypercarbia). With regard to diagnosis and monitoring, clinical examination alone can be challenging and insufficiently sensitive, particularly for the confirmation of brain death. Computed tomography is the main imaging modality for acute neurologic assessment because magnetic resonance imaging is not feasible in these patients. Options for neuromonitoring are limited, although cerebral near-infrared spectroscopy may be useful. There are very limited data to guide the management of specific complications such as intracranial hemorrhage, which remains a leading cause of mortality in ECMO patients. CONCLUSIONS ECMO can be lifesaving and is being used increasingly for severe respiratory and/or cardiac failure. However, it remains associated with significant neurologic morbidity and mortality. Greater research clearly is needed to determine the best approach to the assessment and management of neurologic complications in this rapidly growing patient population.

Implantable cardioverter defibrillator therapy in hypertrophic cardiomyopathy: an updated systematic review and meta-analysis of outcomes and complications

BACKGROUND Since the introduction of the implantable cardioverter-defibrillator (ICD) in patients with hypertrophic cardiomyopathy (HCM), the incidence of sudden cardiac death (SCD) has been significantly reduced. Given its widespread use, it is important to identify the outcomes associated with ICD use in patients with HCM. The present paper is a systematic review and meta-analysis of the rates of appropriate and inappropriate interventions, mortality, and device complications in HCM patients with an ICD. METHODS We conducted a systematic review and meta-analysis on 27 studies reporting outcomes and complications after ICD implantation in patients with HCM. ICD interventions, device complications, and mortality were extracted for analysis. RESULTS A total of 3,797 patients with HCM and ICD implantation were included (mean age, 44.5 years; 63% male), of which 83% of patients had an ICD for primary prevention of SCD. The cardiac mortality was 0.9% (95% CI: 0.7-1.3) per year and non-cardiac mortality was 0.8% (95% CI: 0.6-1.2) per year. Annualized appropriate intervention rate was 4.8% and annualized inappropriate intervention was 4.9%. The annual incidence of lead malfunction, lead displacement and infection was 1.4%, 1.3%, and 1.1%, respectively. CONCLUSIONS ICD use in patients with HCM produces low rates of cardiac and non-cardiac mortality, and an appropriate intervention rate of 4.8% per year. However, moderate rates of inappropriate intervention and device complications warrant careful patient selection in order to optimize the risk to benefit ratio in this select group of patients.