Atrial Fibrillation in the Elderly

To Ablate or Not to Ablate

Avishag Laish-Farkash, M.D., Ph.D.; Vladimir Khalameizer, M.D.; Amos Katz, M.D.

Disclosures

J Cardiovasc Electrophysiol. 2013;24(7):739-741. 

Editorial Comment

The reality that atrial fibrillation (AF) is the most frequently encountered arrhythmia in clinical practice, and that the incidence and prevalence of AF appears to be on the rise, is well known. This reality presents new challenges for cardiovascular practitioners and for the electrophysiology community. There is an increase in incidence of AF with age.[1] The median age of patients with AF is 75 years, with prevalence of 2.3% and 5.9% in people older than 40 years and 65 years, respectively. Approximately 70% of individuals with AF are between 65 and 85 years of age.[2] Beyond the sheer numbers of the elderly with AF, this population presents unique challenges to disease management. Elderly patients are more likely to have comorbid illnesses including hypertension, congestive heart failure, and left ventricular hypertrophy, placing them at increased risk for thromboembolic complications with AF and antithrombotic therapy complications.[3] Age-related degenerative changes in the cardiac conduction system predispose the elderly to sick sinus syndrome and tachycardia–bradycardia syndrome.[4] The age-related pharmacologic and pharmacodynamic changes in the antiarrhythmic drugs (AAD) increase the predilection for side effects and pro-arrhythmias.[5–7] This makes pharmacologic rhythm control difficult to achieve in elderly patients with symptomatic paroxysmal and persistent AF. Until recently, there has been a paucity of data regarding the use of catheter ablation for maintenance of sinus rhythm in the elderly population (particularly those ≥ 70 years of age). Most AF ablation procedures have been performed in white male patients younger than 70 years of age.[8] Probable reasons for this are comorbidities and fragility of elderly patients. Younger patients have fewer periprocedural complications, thus avoiding the age-related atrial substrate modification [2] that leads to AF perpetuation and reduced chance of AF sinus rhythm maintenance. With increasing life expectancy, the elderly are the most rapidly expanding portion of our population, making AF an even more important public health concern. Given that elderly patients with symptomatic paroxysmal or persistent AF may be less tolerant of AAD than their younger counterparts, catheter ablation for the elderly could prove to be an important treatment strategy.

There are no randomized prospective trials comparing the safety and efficacy of catheter ablation with best medical therapy for paroxysmal or persistent AF in the elderly. As AF ablation has become more widespread, the clinical population has broadened, providing us with greater insight into the potential efficacy in elderly patients as well as those with more advanced structural heart disease. Several observational studies analyzing efficacy, safety, and outcomes of AF ablation in septuagenarians and octogenarians have been published.
Zado et al.,[9] in a single-center study, analyzed the procedural outcomes of 1,165 patients with drug refractory AF who underwent 1,506 ablation procedures between 2000 and 2007. The ablation procedure consisted of elimination of all provocable pulmonary vein triggers and nonpulmonary vein triggers of AF. For selected patients all 4 pulmonary veins were isolated. Follow-up patient monitoring consisted of routine office follow-up and surveillance with transtelephonic monitoring, as well as the ability to transmit symptomatic episodes. Patients were subdivided into 3 age groups: < 65 years (n = 948), 65–74 years (n = 185), and ≥ 75 years (n = 32). The periprocedural complication rate was low with no difference among the 3 age groups (major complication rates of 1.6% in group 1, 1.7% in group 2, 2.9% in group 3, P= NS). Among the 781 patients who completed the minimum 1 year of follow-up, there was no difference between the groups for ablation success. However, the oldest group was more likely to demonstrate a partial response to ablation and require AAD and anticoagulation.
Corrado et al. [10] reported a retrospective multicenter experience of 175 patients older than 75 years of age who underwent catheter ablation for symptomatic AF that was refractory to at least one AAD. The ablation procedure consisted of pulmonary vein antrum isolation and isolation of the superior vena cava, guided by circular mapping catheter and intracardiac echo. Patients were followed up at 3, 6, 9, and 12 months after the procedure and every 6 months thereafter. The mean age in this study was a 77 ± 6 year with 55% and 45% of patients with paroxysmal and persistent AF, respectively. Mean follow-up was 20 ± 14 months; 73% (127/174) maintained sinus rhythm (SR) after a single ablation procedure and the complication rate was 1%. After a second ablation, 143/174 (82%) maintained SR without AADs; an additional 22 patients were able to maintain SR with AADs. Thus 94% of patients remained in SR at almost 2 years of follow-up after an ablation strategy with a very low rate of major procedure-related complications.

Santangeli et al.[11] performed AF ablation on a group of 103 octogenarians (age 85 ± 3 years, 4 >90 years). After a mean follow-up of 18 months, 69% of octogenarians were free of AF without AAD after a single procedure versus 71% in those younger than 80 years of age (P = 0.65). The success rate increased to 87% after 2 procedures. Bunch et al.[12] evaluated AF ablation in patients ≥ 80 years (n = 35) and <80 years (n = 717). AF ablation consisted of pulmonary vein antral isolation with or without additional linear lesions. The hospital stay was longer in the older patient cohort (2.9 ± 7.7 vs 2.1±1.1 days, P = 0.001). There was no increased risk of periprocedural complications. One-year survival free of AF or flutter was 78% in those >80 and 75% in those <80 years (P = 0.78).

Alternative strategies in the elderly are AV node (AVN) ablation plus pacemaker placement. In the PABA-CHF study[13] in a relatively young population (mean age 60 ± 8 years) pulmonary-vein isolation was superior to AVN ablation with biventricular pacing in patients with heart failure who had drug-refractory AF. Hsieh et al.[14] compared the long-term results (>4 years) of 71 elderly patients (>65 years old) with medically refractory paroxysmal AF who were assigned to either AVN ablation plus single-chamber (VVI or VVIR) pacemaker, versus pulmonary vein isolation, AF was better controlled in the group with AVN ablation and pacemaker placement than in the group with AF ablation (100% vs 81%, P = 0.013). Most other outcome variables favored the AF ablation.

In this issue of the Journal, Blandino et al.[15] have published the first prospective study that directly compares AADs versus catheter ablation in elderly patients. Four hundred and twelve consecutive patients aged ≥70 years with symptomatic persistent AF refractory to at least one AAD underwent ablation (n = 153) or AAD treatment (n = 259), according to their personal preference. Pulmonary vein isolation (PVI) and cavotricuspid isthmus ablation were performed in the entire ablation group, and 60% underwent left atrial linear lesions at the roof and left isthmus as well. Eighteen percent underwent a second procedure and 25% continued AAD prophylaxis. The AAD group underwent successful electric cardioversion (ECV) after 4 weeks of AAD and continued the AAD thereafter. After a mean follow-up of 60 ± 17 months, catheter ablation was more effective in maintaining sinus rhythm than AAD (76% vs. 46%, respectively, P < 0.001). Due to higher rate of SR maintenance, the ablation group was more likely to discontinue AAD (67% vs 28%, P < 0.001) and oral anticoagulation (74% vs 43%, P < 0.001), with a consequent greater reduction of long-term adverse events (7.7% vs 23.9%, P < 0.001) and greater improvement in quality of life scores. On the other hand, the catheter ablation group was affected by higher acute complication rate (6.7% vs 1%, P < 0.001), mainly periprocedural cerebral thromboembolism (3.3% vs 0.7%, P = 0.058). Previous history of TIA/stroke was found to be the only independent predictor for this complication (OR 1.203, 95% CI 1.113–1.301, P < 0.001). In this first prospective study with randomization of patients to 2 treatment options, the overall results are encouraging and supportive for the ablation approach and add to the view that age should not preclude patients from AF ablation. The relatively high rate of cerebral thromboembolic events emphasizes that appropriate selection of patients for this procedure is crucial to prevent peri- or postprocedural complication. The status "relatively healthy septuagenarian, octogenarian patient" should be considered for inclusion as candidates suitable for the AF ablation procedure.

Current guidelines do not consider elderly patients separately regarding recommendations for AF ablation. Due to lack of prospective studies, this issue cannot be addressed; no support exists for a clinical decision regarding older patients. Whether to ablate or not remains solely the physician's clinical judgment. The 2011 ACCF/AHA/HRS Focused Update on the Management of Patients with Atrial Fibrillation mentioned that the average age of patients undergoing catheter ablation was relatively young at 55.7 years (95% CI, 54.1–57.4), and does not directly address the age issue.[16] The 2012 HRS/EHRA/ECAS Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation states that "It remains uncertain what the safety and efficacy of AF ablation is for other populations of patients, especially patients with persistent and longstanding persistent AF, elderly patients, and patients with heart failure."[17] The 2012 focused update of the ESC Guidelines for the management of AF addresses the age issue only briefly and mentions that the complication rates are also related to age and therefore risk associated with AF ablation needs to be carefully weighed against the individual symptomatic benefit.[18] Future guidelines should address the heterogeneity of AF and the impact of age, and cardiovascular comorbidities.

The ongoing Catheter Ablation versus Anti-arrhythmic Drug Therapy for Atrial Fibrillation Trial (CABANA trial, NCT00578617), enrolling patients up to age 90 years, is expected to be very valuable in this regard.[19] However, it will take many years until the data are conclusive, and perhaps by then the ablation procedure tested will be rendered obsolete. In the meantime, we will have to make the best clinical decision for our patients.

The incidence and prevalence of atrial fibrillation (AF) increase with age. Catheter ablation has been suggested to improve the quality of life of patients with AF. Elderly patients have historically been under-represented in AF clinical trials. As physicians we are often left to extrapolate data and form our own conclusions as to whether we feel an elderly patient may benefit from a new technology that has proven effective in a younger cohort. Several nonrandomized clinical studies have recently addressed the issue of catheter ablation for rhythm control—mostly PVI in elderly patients and show favorable rates of success. Unfortunately, these studies are limited by the relatively small numbers of patients examined and often by their single-center and retrospective nature. Randomized trials of catheter ablation will be necessary before this procedure can be promoted for wider use in the older patient. The current first prospective study supports the benefit of catheter ablation for AF rhythm control in elderly patients and emphasizes the importance of appropriate patient selection, and considers revision of comorbidities such as prior TIA/stroke and the CHADS2 score before considering elderly patients for AF ablation.

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