Prognostic Value of High-sensitive Troponin T for Predicting Cardiovascular Events After Atrial Fibrillation Ablation

Shota Tamura MD; Atsushi Doi MD, PhD; Masanori Matsuo MD; Hisashi Katayama MD; Tomotaka Yoshiyama MD; Hiroaki Tatsumi MD, PhD; Yasuhiro Izumiya MD, PhD; Minoru Yoshiyama MD, PhD

Disclosures

J Cardiovasc Electrophysiol. 2019;30(9):1475-1482. 

In This Article

Discussion

The findings of our study were as follows: (a) Patients with hs-TnT greater than or equal to 0.014 μg/L were more likely to be older; had the highest prevalence of hypertension and eGFR lesser than 60 mL·min−1·1.73 m−2; and had the highest CHA2DS2-VASc score, BNP levels, LAD, and E/e′ ratio among the three groups. (b) The incidence of MACE occurrence after AF ablation was the highest in patients with hs-TnT greater than or equal to 0.014 μg/L. (c) In the univariate analysis, hs-TnT greater than or equal to 0.014 μg/L, CHA2DS2-VASc score, and persistent AF were associated with the composite endpoint including AF recurrence or MACE after AF ablation. Multivariate analysis revealed that hs-TnT greater than or equal to 0.014 μg/L and persistent AF were independent predictors of the composite endpoint. To our knowledge, this is the first study to show that the hs-TnT level is a useful predictor of AF recurrence or MACE after CF-RFCA and CBA, beyond the CHA2DS2-VASc score.

Atrial Fibrillation Ablation

Previous meta-analyses of clinical trials showed that CF-RFCA and CBA led to a higher rate of durable PVI and freedom from AF than non–CF-RFCA and that the incidence of freedom from AF was approximately 80% at greater than or equal to 12 months of follow-up.[13,14] In our study, during a mean follow-up period of 15 ± 8 months, AF recurrence occurred in 25% of the patients after a single procedure, and the incidence of freedom from AF recurrence was relatively high. Previous studies reported that the presence of an atrial low-voltage area on contact mapping and delayed enhancement on magnetic resonance imaging were independent predictors of AF recurrence after the ablation,[15–17] and that the severity of the atrial arrhythmogenic substrate was associated with AF recurrence. Recently, Nakanishi et al reported that an elevated hs-TnT level was associated with AF recurrence after non–F-guided PVI.[18] We demonstrated that patients with hs-TnT greater than or equal to 0.014 μg/L tended to have the highest incidence of AF recurrence after a single procedure with CF-RFCA or CBA. Moreover, we showed that patients with hs-TnT greater than or equal to 0.014 μg/L had the largest E/e′ ratio and LAD. Previous studies reported that a high E/e′ ratio and large left atrial volume were associated with the presence of left atrial low-voltage areas and that these parameters were useful markers for predicting AF recurrence after the ablation.[16] This finding suggests that an elevated hs-TnT level may also be associated with an advanced atrial arrhythmogenic substrate.

Clinical Outcomes

Previous studies have shown that catheter ablation of AF reduced the incidence of mortality and MACE compared with medical therapy.[5,6] However, some high-risk patients often develop MACE after AF ablation. In our study, MACE occurred in 4% of the patients during a mean follow-up of 15 ± 8 months (mortality: 0%, stroke: 0.9%, acute coronary syndrome: 0.4%, and heart failure hospitalization: 3.1%). Previous studies showed that the incidence of mortality and stroke is approximately 0.5% to 0.8% and 0.7% to 2.0% per year, respectively,[5,6] and our result was almost consistent with those findings.

The hs-TnT level has been shown to improve the risk assessment for future AF occurrence in patients without AF. Moreover, the ARISTOTLE Investigators reported that an elevated hs-TnT was independently associated with an increased risk of stroke, cardiac death, and major bleeding in patients with AF and that hs-TnT improved the risk stratification beyond the CHA2DS2-VASc score.[11] We demonstrated that hs-TnT greater than or equal to 0.014 μg/L was associated with MACE after AF ablation. Some studies have shown that the maintenance of sinus rhythm reduced the mortality and MACE rates after AF ablation.[3–6] We showed that the AF recurrence rate tended to be higher in patients with hs-TnT greater than or equal to 0.014 μg/L, and this finding provides a convincing explanation for the relationship between an elevated hs-TnT level and MACE after AF ablation. However, the presence of underlying cardiovascular diseases and other comorbidities can be related to the occurrence of MACE even after a successful AF ablation. Previous studies have shown the prognostic value of left atrial volume and E/e′ ratio in nonischemic-dilated cardiomyopathy.[19] We demonstrated that patients with an elevated hs-TnT level had a large LAD and E/e′ ratio and a high prevalence of chronic renal diseases. These findings also suggest that an elevated hs-TnT level might be associated with MACE after AF ablation. Moreover, we showed that hs-TnT was associated with MACE after AF ablation, regardless of the presence of chronic renal diseases and previous ischemic disease. Therefore, we believe that hs-TnT is useful for predicting MACE occurrence after AF ablation.

In our study, multivariate analysis revealed that hs-TnT greater than or equal to 0.014 μg/L was an independent predictor of the composite endpoint including AF recurrence or MACE, beyond the CHA2DS2-VASc score. It is noteworthy that the determination of hs-TnT levels can identify high-risk patients among those with a low CHA2DS2-VASc score. We believe that our data are useful in the decision making about oral anticoagulant use, medical treatments, and aggressive cardiovascular risk factor management for individual patients after AF ablation.

Study Limitations

Our study has several limitations. First, this was a single-center retrospective study with a relatively small number of patients and a short follow-up period (15 ± 8 months). Prospective randomized studies with a longer follow-up period and a much larger patient population are needed to confirm whether hs-TnT is a useful marker for risk stratification after AF ablation. Second, the incidence of AF recurrence may have been underestimated because long-term monitoring methods based on 7-day ambulatory monitoring or implantable loop recorders were not used. Third, individualized therapy may have influenced the risk of MACE. However, system-wide guidelines have been established, and some cardiologists at our hospital carried out the individual patient management after AF ablation according to those guidelines. Forth, the hs-TnT level was evaluated only at once before the procedure. We think that a future study should be needed to measure hs-TnT levels before and after the procedure. Fifth, we did not measure several inflammatory markers or myocardial damage markers. Finally, we could not show the mechanism by which hs-TnT predicts AF recurrence and MACE after AF ablation. We believe that the mechanisms for this independent relationship are multifactorial because hs-TnT is related to many clinical risk factors.

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