Early mortality following atrial fibrillation (AF) ablation affects nearly one in 200 patients, with the majority of deaths occurring during 30-day readmission, an analysis of a nationally representative US cohort has revealed. Writing in the Journal of the American College of Cardiology (JACC), Edward P Cheng (Weill Cornell Medicine-New York Presbyterian Hospital, New York, USA) et al report that procedural complications, congestive heart failure, and low hospital AF ablation volume were predictors of early death after ablation. They recommend: “Prompt management of post-procedure complications and congestive heart failure may be critical for reducing mortality rates following AF ablation.”
Although procedure-related deaths during the index admission following catheter ablation of AF have been reported to be low, adverse outcomes can also occur after discharge. Because data on early mortality after AF ablation are limited, Cheng and colleagues aimed to examine mortality occurring soon after discharge from admission for AF ablation. They write: “As the overall volume of AF ablation procedures performed worldwide continues to grow, an understanding of the real-world rates of serious complications after AF ablation is needed. Recent studies have suggested an increasing trend in AF ablation related complication rates, despite advances in catheter technology and operator experience.”
The authors evaluated 60,203 admissions for AF ablation in patients ≥18 years between 2010 and 2015 from the all-payer, US Nationwide Readmissions Database (NRD). The definition of early mortality was death during initial admission or 30-day readmission. Other endpoints included procedural complications such as perforation/tamponade, other iatrogenic cardiac complications, central nervous system complications, vascular complications, and pneumothorax. Only the first readmission within 30 days after discharge was included in the analysis. Comorbidities, procedural complications, and causes of readmission (by organ system and by cardiac cause) were identified by International Classification of Diseases–9th Revision, Clinical Modification (ICD-9-CM) codes.
Cheng et al found that early mortality occurred in 0.46% cases (95% confidence interval [CI] 0.37–0.52) following AF ablation. Of the 276 patients who died early after AF ablation, 126 (45.7%) died during index admission, and 150 (54.3%) died during 30-day readmission after AF ablation. Patients who died early following AF ablation were older, and had a higher burden of comorbidities such as congestive heart failure, coronary artery disease, previous placement of pacemakers, pulmonary hypertension, chronic lung disease, chronic kidney disease, anaemia, and coagulopathy than those who survived. Patients who died early also had a higher burden of comorbidities than survivors (40.1% vs. 14.4%, respectively, p<0.001), and were less likely to have had procedures performed at higher-volume centres and teaching hospitals. They also lived in lower household-income neighbourhoods, and had longer lengths of index hospitalisations than those who survived.
Between 2010 and 2015, quarterly rates of early mortality post-ablation increased from 0.25% to 1.35% (p for trend <0.001). This paralleled significant increases in the mean age of patients at time of ablation, and in the prevalence of comorbidities such as CHF, coronary artery disease, chronic lung disease, and chronic kidney disease. The median time from ablation to death was 11.6 days (interquartile range [IQR] 4.2–22.7).
Following adjustment for age and comorbidities, procedural complications (adjusted odds ratio [aOR] 4.06, p<0.001), congestive heart failure (CHF) (aOR 2.20, p=0.011) and low AF ablation hospital volume (aOR 2.35, p=0.003) were associated with early mortality. Other associated complications were cardiac perforation (aOR 2.98, p=0.007), other cardiac (aOR 12.8, p<0.001), and neurological aetiologies (aOR 8.72, p<0.001).
Cheng and colleagues say: “Our study provides real-world evidence that the rates of early mortality after AF ablation are not insignificant and can occur in nearly one of 200 procedures. The 0.46% rate of early mortality found in our study exceeds the rates of procedural death reported by other large studies examining AF ablation outcomes.” They attribute this to the fact that other studies have been based on voluntary responses to surveys, or did not include deaths occurring after discharge from index admission, which “could have led to significant underestimation of the true mortality rate”.
They also highlight the “alarming rise in the rate of early deaths between 2010 and 2015”. According to the authors, this trend can be explained by two main factors—the increased number of comorbidities that they identified in the analysis, and a greater volume of procedures being performed at lower volume centres.
Among the limitations they point to are that it was a retrospective study based on an administrative database, and was therefore limited by the accuracy of ICD-9-CM codes. In addition, any sudden deaths outside the hospital prior to readmission would not have been included: “Therefore, the early mortality rate after AF ablation reported in this study likely represents an underestimation of the true rate.”
Concluding, Cheng et al write: “Sepsis and CHF were the leading primary causes of readmission associated with mortality. Implementation of strategies to reduce procedural complications, optimise CHF management, and reduce nosocomial infections may help reduce early mortality after AF ablation. Protocols that optimise management of heart failure and minimise procedural complications warrant further study to reduce the impact of these factors on the outcomes of AF ablation.”
In an accompanying editorial comment, also published in JACC, Hugh Calkins (John Hopkins Hospital, Baltimore, USA) describes the analysis as “a very important study that should serve as a wake-up call to all electrophysiologists who perform AF ablation, all cardiologists who refer patients for this procedure, and all patients who are considering undergoing AF ablation”, adding: “What is clear is that AF ablation is not a benign procedure, and mortality is a very real complication of the procedure. Cheng et al have also taught us that we need to define early mortality as mortality during the index hospitalisation as well as a subsequent hospitalisation within 30 days. It is also clear that experience matters. There is no doubt that the best outcomes are obtained at high-volume hospitals by high-volume operators.”
Jim W Cheung, the senior author of the study, told Cardiac Rhythm News; “This study offers some sobering findings. It clearly highlights the gap between the published outcomes by high volume centres in clinical trials and the outcomes seen in the real world. Efforts are needed to bridge this gap and to ensure that outcomes from AF ablation procedures performed in widespread practice match the benchmarks of efficacy and excellent safety that have been established by experienced centres. It is essential for practising clinicians to recognise that patients should be followed closely after discharge from AF ablation, as adverse events can occur late and may require timely intervention before they became life-threatening.”