Very long-term outcomes of patients undergoing catheter ablation of atrial fibrillation: a systematic review and meta-analysis

Background

The efficacy of catheter ablation of atrial fibrillation (AF) is reported to stabilise at 5-year, but most studies report up to 3-year-outcomes only.

Objective

To perform a systematic review and meta-analysis of outcomes at 5-years following AF ablation.

Methods

We searched PubMed and Embase for studies reporting on ≥5-year outcomes following AF ablation, including freedom from atrial arrhythmia, all-cause death, stroke, and major bleeding. All meta-analyses were performed using the “meta” package in R with pooled incidence calculated using log transformation.

Results

Among 5,764 studies screened, 58 (n=41,344 patients) were included for analysis. The pooled mean age was 60.3y, 68.7% male, 78.4% paroxysmal AF, and radiofrequency was the most common ablation energy (72.4%). Most (51.5%) patients had hypertension, but the pooled rates of other comorbidities were low (heart failure: 9.0%, coronary artery disease: 12.8%, diabetes: 11.0%, and previous stroke: 8.5%). Pooled incidence of freedom from atrial arrhythmia at 5-years was 47.6% (95% CI 43.8%-51.6%, I2=98.4%) after a single procedure and increased to 64.3% (95% CI 59.6%-69.3%, I2=98.3%) after multiple procedures (Figure 1). The incidence was higher among patients with paroxysmal compared with non paroxysmal AF (55.9% vs. 28.7% and 82.2% vs. 47.6% after single and multiple procedures respectively). Retrospective studies reported slightly higher incidence of arrhythmia freedom (single procedure: 51.2% vs. 46.7%; multiple procedures: 66.9% vs. 61.9%) than did prospective studies. Few studies reported outcomes other than atrial arrhythmia free survival at 5-years (n=14) and incidences of these outcomes could only be pooled for multiple procedures. Pooled incidences of death, stroke, and major bleeding at 5-years were 8.0% (95% CI 4.2%-15.2%, I2=95.8%), 2.3% (95% CI 1.4%-3.6%, I2=72.9%), and 1.1% (95% CI 0.6%-1.8%, I2=32.5%), respectively (Figure 2).

Conclusion

At five-years, only up to 65% of patients undergoing AF ablations remained free from atrial arrhythmia although there was significant heterogeneity among individual studies. Encouragingly, these patients had low risk of dying, experiencing a stroke or major bleeding (all incidences<10%).

Funding Acknowledgement

Type of funding sources: None.

Long-term outcomes of 265,737 patients hospitalised with atrial fibrillation and atrial flutter from 2008 to 2015

Background

Atrial fibrillation/atrial flutter (AF/AFL) hospitalisations are common, however, little is known about the long-term outcomes of these episodes.

Objective

To examine the incidence of mortality, all-cause and cause-specific re-hospitalisations at up to 8 years after a hospitalisation for AF/AFL.

Methods

Unique patients hospitalised with a primary diagnosis of AF/AFL from 2008–2015 were identified using nation-wide hospitalisation data from Australia and New Zealand. All-cause mortality was the primary outcome. Secondary endpoints included all-cause and cause-specific re-hospitalisations. Results were reported as incident rate per 100 patient-years.

Results

We included 265,737 patients (mean age 69.9±13.9y, female 45.2%, elective 28.7%). The median length of stay was 1 day (Interquartile range [IQR] 0–4 days) and the median CHA2DS2-VASc score was 2 (IQR 1–2). During the index hospitalisation, 9,837 (3.7%) patients underwent catheter or surgical ablation and 52,634 (19.8%) underwent cardioversion. During the median follow-up time of 3.4 years (range 0–8.0 years), 53,669 patients died (incident rate of 5.7/100 patient-years) with a survival probability gradually decreasing from 92.8% (95% CI 92.7–92.9%) at 1-year to 65.4% (95% CI 64.9–65.8%) at 8-years post-discharge (Table 1 and Figure 1). All-cause re-hospitalisations occurred in 210,118 patients (incident rate of 22.2/100 patient-years) with a rehospitalisation-free survival probability of 7.1% (95% CI 6.9—7.3%) at the end of follow-up. Unplanned re-hospitalisations occurred more frequently than planned episodes (incident rate of 17.2 vs. 16.6/100 patient-years respectively). AF/AFL accounted for 25.1% of all-cause re-hospitalisations (incident rate of 8.9/100 patient-years) and the probability of freedom from re-hospitalisations for AF/AFL was 55.4% (95% CI 55.0–55.8%) at 8-years. Incident rates of re-hospitalisations for catheter ablation (1.5/100 patient-years), stroke (1.6/100 patient-years), heart failure (2.7/100 patient-years), and acute myocardial infarction (1.0/100 patient-years) were low. In subgroup analyses, worse survival was observed in female patients, older age groups, patients with comorbid heart failure, hypertension, diabetes, and those who did not undergo ablation during the index hospitalisation.

Conclusion

Nearly two-thirds of patients were surviving by 8-years following an AF/AFL hospitalisation with a low rate of re-hospitalisations for stroke, heart failure, and myocardial infarction. However, re-hospitalisations for recurrent atrial arrhythmia were common. Efforts to reduce re-hospitalisations, especially unplanned encounters, are required to improve patient outcomes.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): National Heart Foundation of Australia

Trends in complications and mortality following catheter ablation of atrial fibrillation: results from 22,582 ablations in Australia and New Zealand from 2010 to 2015

Background

Recent studies from the United States report rising rates of in-hospital complications and mortality following catheter ablation of atrial fibrillation (AF) but whether such a trend is observed in other populations is uncertain.

Purpose

To examine the trends in complications and mortality following AF ablations up to 30 days after discharge in Australia and New Zealand (ANZ) using nationwide data.

Methods

All patients ≥18y undergoing catheter ablation of AF from 2010–2015 were identified using hospitalisation data from all public and most private hospitals in ANZ. The primary endpoint was one or more procedural complications during the hospital stay or within 30 days of discharge. The secondary endpoints were mortality and other specific complications. Unadjusted trend was evaluated using Cochran-Armitage test while that of complications, adjusting for differences in other characteristics, was evaluated using multivariate logistic regression with the year of ablation modelled as a continuous variable. Results are reported as odd ratios (OR) and 95% confidence intervals (CI).

Results

A total of 22,582 AF ablations were included (mean age 62.2±11.6y, 29.1% female, 94.4% elective procedures). The number of ablations increased by 26.4% during the study period (3,097 in 2010 to 3,915 in 2015). Rates of heart failure (8.98% to 10.09%, p for trend=0.010), diabetes (4.52% to 12.46%, p<0.001), chronic kidney disease (2.36% to 4.29%, p<0.001) significantly increased over time but that of hypertension decreased (15.27% to 12.29%, p<0.001). The incidence of overall complications (6.55% in 2010 to 6.67% in 2015, OR 0.99, 95% CI 0.96–1.03) was unchanged during the study period (Figure 1A). When individual complications were considered, mortality rate was low with no statistically significant change with time (0.19% to 0.15%, OR 1.03, 95% CI 0.84–1.28) (Figure 1A) while the rate of acute kidney injury (0.23% to 0.51%, OR 1.17, 95% CI 1.02–1.34) increased and that of venous thromboembolism (0.16% to 0.0%, OR 0.71, 95% CI 0.54–0.94) decreased (Figure 1B). Though the incidence of any bleeding (4.49% to 3.98%, OR 0.97, 95% CI 0.93–1.01) was unchanged, that of major bleeding requiring blood transfusion (0.97% to 0.64%, OR 0.87, 95% CI 0.79–0.96) declined significantly (Figure 1B). No significant trend was observed in other complications or when in-hospital (5.13% to 5.21%, OR 1.00, 95% CI 0.97–1.04) and post-discharge (1.55% to 1.63%, OR 0.97, 95% CI 0.91–1.03) complications were separately evaluated.

Conclusions

Though more patients with heart failure, diabetes and chronic kidney disease underwent catheter ablation of AF over time in ANZ, the overall complication rate was unchanged with a significant decrease in the incidences of major bleeding and venous thromboembolism. However, rate of acute kidney injury nearly doubled, and this could be a potential target for efforts to further improve procedural safety.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): The National Heart Foundation of Australia

Differences between public and private hospitals in complications following catheter ablation of atrial fibrillation: a cohort study in Australia

Background

Comparing outcomes of care between public and private hospitals is critical to inform patients and improve care quality.

Purpose

To compare complication rates following catheter ablation of atrial fibrillation (AF) up to 30-days post discharge between public and private hospitals.

Methods

We included patients ≥18 years who underwent AF ablation in the Australian states of New South Wales, Queensland, Victoria, and Western Australia from 2010–2015. The primary outcome was the occurrence of any complication up to 30-days after discharge. The association between provider type and the risk of complications was examined using logistic regression with inverse probability of treatment weighting (IPTW) propensity scores to account for differences in measured confounders. The minimum strength of association required for an unmeasured confounder to nullify any observed association was estimated using the E value.

Results

We identified 18,074 AF ablations during the study period (mean age 62.3±11.4y, 28.8% female, 78.4% performed in private hospitals). Patients ablated at public hospitals were younger (59.3 vs. 63.1y, p<0.001) but had higher rates of heart failure (10.3% vs. 7.7%, p<0.001), diabetes (10.9% vs. 7.9%, p<0.001), chronic kidney disease (4.9% vs. 2.2%, p<0.001), and chronic lung diseases (4.2% vs. 3.6%, p=0.046) than those at private hospitals. The unadjusted rate of complications was higher in publics hospitals compared with private ones (7.59% vs. 5.26%, p<0.001). After IPTW, there was good covariate balance with a median standardised difference of 0.006 (range 0.0–0.032) and the adjusted difference in procedural complication rates between two sectors remained significant (OR=1.46, 95% CI 1.24–1.73). The difference was mainly driven by an elevated risk of complications requiring cardiac surgery (OR=3.85, 95% CI 1.35–10.98), acute kidney injury (OR=2.95, 95% CI 1.12–7.74), cardiorespiratory failure (OR=2.69, 95% CI 1.19–6.04), postprocedural infection (OR=2.50, 95% CI 1.28–4.86), and bleeding (OR=1.26, 95% CI 1.02–1.56) (Figure 1). The disparity in the complication rates persisted when in-hospital (OR=1.41, 95% CI 1.16–1.70) and post-discharge (OR=1.52, 95% CI 1.12–2.07) complications were analysed separately. The E value was 1.79, suggesting that the disparity might plausibly be explained by unmeasured confounders.

Conclusion

AF ablation at a public hospital was associated with a 46% higher risk of complications compared with ablation at a private hospital, mainly driven by a higher risk of complications requiring cardiac surgery, acute kidney injury, cardiorespiratory failure, infections, and bleeding. The disparity could be due to differences in care quality between two sectors or explained by unmeasured confounders such as higher procedural complexity in public hospitals.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): The National Heart Foundation of Australia

P347Complications of catheter ablation for atrial fibrillation: a nation-wide study in Australia and New Zealand

Background

It is important to investigate complications of catheter ablation for atrial fibrillation (AF) - an increasingly common procedure - to inform patients and guide efforts to improve procedural quality. However, clinical trials and registries are limited by selection bias, while existing population-based studies either lack nation-wide data, or fail to report post-discharge complications. The timing and impact of these complications are also poorly understood.

Purpose

To obtain unbiased and comprehensive estimates of complications of AF ablations using national data from Australia and New Zealand. We also evaluated the impact of in-hospital complications on the length of stay and assessed the timing of post-discharge complications.

Methods

We included patients aged ≥18 years undergoing catheter ablation with a primary diagnosis of AF between 2010–2015 in all public and most private hospitals in Australia and New Zealand. The primary outcome was the occurrence of major complications in-hospital or up to 30-days after discharge. We identified major complications based on a literature review and expert clinical opinion and defined these using International Classification of Diseases – 10th revision, Australian Modification diagnoses codes and Australian Classification of Health Interventions procedure codes. We determined the impact of in-hospital complications on the length of stay, adjusting for other covariates, by using negative binomial regression, and reported results as incident rate ratio (IRR) and 95% confidence intervals (CI). Time to first post-discharge complication was evaluated using Kaplan Meier survival analysis.

Results

A total of 20,057 AF ablations were included (mean age 62.1±11.6 y, 56.7% ≤65 years old; 29.2% female; median length of stay 1 day). Of these, major complications occurred in 6.3% procedures (4.6% occurring in-hospital and a further 2.0% occurring in the 30-day post discharge). The most common complications were bleeding or haematoma formation and perforation (primarily pericardial effusion), which accounted to 60.3% and 14.3% of all complications, respectively. Rate of procedure-related deaths was 0.1%. Occurrence of an in-hospital complication more than doubled the length of stay (IRR: 2.3, 95% CI 2.2–2.4) with complications requiring cardiac surgery (IRR 4.5, 95% CI 3.2–6.4) and vascular injuries (IRR 3.9, 95% CI 3.1–4.9) having the length of stay prolonged the most (Figure 1A). In the first-week, 67.3% of post-discharge complications had occurred, and this number reached 95% within three-weeks (Figure 1B).

Conclusions

Major complications after AF ablation were common. In-hospital complications doubled the length of stay. Approximately 30% of complications occurred after discharge with the risk highest in the first seven days. Efforts to reduce complications should focus on reducing the incidence of bleeding and pericardial effusions which counted for more than 75% of all complications.

Acknowledgement/Funding

National Heart Foundation of Australia, The Hospital Research Foundation