Rate, trends and predictors of early mortality after AF ablation
Risk of Mortality Following Catheter Ablation of Atrial Fibrillation
Introduction and methods
The number of AF ablation procedures performed worldwide increases, therefore, there is a need to understand real-world rates of serious complications after ablation. Studies have suggested there is a increase in AF ablation related complication rates [1,2]. In-hospital mortality related to AF ablation during index admission has been estimated to be between 0% and 0.8% [1,3-9]. But rates of mortality due to complications that can occur during readmission are unknown.
This study examined real-world data on the rate, trends and predictors of early mortality after AF ablation, defined by combined in-hospital mortality during index admission or 30-day readmission following catheter ablation of AF. For this purpose 60,203 admission records of patients undergoing AF ablation from 2010 to 2015 from the Healthcare Cost and Utilization Project (HCUP) and Nationwide Readmissions Database (NRD) were identified.
The primary endpoint was all-cause early mortality following AF ablation, defined as mortality occurring either at index AF ablation admission or at 30-day readmission following ablation.
- Overall mortality rate after AF ablation was 0.46% (95%CI:0.37-0.52%). Of the 276 patients who died, 126 (45.7%) died during index admission and 150 (54.3%) during 30-day readmission. Median time to death was 11.6 (IQR:4.2-22.7) days.
- Compared with survivors, patients who died were older, had a higher burden or comorbidities (40.1% vs. 14.4% with Elixhauser comorbidity scores ≥4, P<0.001), were less likely to have procedures performed at higher-volume centers and teaching hospitals, resided in lower household-income neighborhoods, had longer lengths of index admission and higher rates of procedural complications (25.6 vs. 6.6%; P<0.001).
- There was a significant increase in quarterly rates of early mortality from 0.25% to 1.35% (P for trend <0.001) between 2010 and 2015. This paralleled with an increase in quarterly rates of index procedural complications, increase in the mean age of patients at time of ablation and increase in the prevalence of comorbidities.
- Procedural complications during index admission were independently associated with early mortality (adjOR: 4.06; 95%CI: 2.40 to 6.85; P<0.001). CHF (adjOR: 2.20; 95% CI: 1.20 to 4.03; P=0.011]), anemia (adjOR: 1.83; 95% CI: 1.13 to 2.96; P=0.015), coagulopathy (aOR: 2.14; 95% CI:1.04 to 4.39; P=0.046), and age (adjOR: 1.04; 95%CI: 1.00 to 1.07; P=0.046) were independently predictive of early death after AF ablation. Patients undergoing AF ablation performed at low-volume centers (low-volume vs. high-volume tertile), had significantly higher odds of early mortality (aOR: 2.35; 95% CI: 1.33 to 4.15; P=0.003).
- Leading causes of readmission in patients who died early were: cardiac (30%), infectious (30%), respiratory (17%), and neurological (12%). The four most common individual primary readmission diagnoses were septicemia (15%), CHF (15%), pneumonia (7.4%), and stroke (5.9%).
In this analysis of a nationally representative real-world cohort using data of >60,000 admission records of patients undergoing AF ablation between 2010 and 2015, early mortality rate was 0.46%. Between 2010 and 2015, a trend for increased rate of early mortality after AF ablation was observed, as for procedural complications and prevalence of comorbidities. Index procedural complications, CHF and low hospital ablation volume were significant associated with a higher risk of early mortality after AF ablation. Sepsis and CHF were the leading causes of readmission in those patients who died early. Optimizing management of AF and reducing procedural complications may be approaches to reduce early mortality after AF ablation.
In his editorial comment , Calkins writes that at first he was surprised by the findings of this study. He himself had never had a patient die after AF ablation and landmark trials such as FIRE and ICE, CASTLE AF and CABANA have reported no deaths. But these studies are all based on high volume operators who predominantly perform procedures at academic centers. Instead, the study by Cheng et al. used the Nationwide Readmission Database, including data of AF ablation performed throughout the US by physicians with variable experience.
He briefly mentions the 2017 Consensus Document on Catheter and Surgical Ablation of Atrial Fibrillations defining training requirements for AF ablation as 50 procedures during fellowship and recommending that operators should perform at least 2 ablation procedures per month to maintain competency. He ends by saying: ‘It is clear that experience matters. There is no doubt that the best outcomes are obtained at high-volume hospitals by high-volume operators.’