New Onset Atrial Fibrillation Following Transcatheter and Surgical Aortic Valve Replacement: A Systematic Review and Meta-Analysis

Machine Learning of Cardiac Anatomy and the Risk of New-Onset Atrial Fibrillation After TAVR

BACKGROUND

New-onset atrial fibrillation (NOAF) occurs in 5% to 15% of patients who undergo transfemoral transcatheter aortic valve replacement (TAVR). Cardiac imaging has been underutilized to predict NOAF following TAVR.

OBJECTIVES

The objective of this analysis was to compare and assess standard, manual echocardiographic and cardiac computed tomography (cCT) measurements as well as machine learning-derived cCT measurements of left atrial volume index and epicardial adipose tissue as risk factors for NOAF following TAVR.

METHODS

The study included 1,385 patients undergoing elective, transfemoral TAVR for severe, symptomatic aortic stenosis. Each patient had standard and machine learning-derived measurements of left atrial volume and epicardial adipose tissue from cardiac computed tomography. The outcome of interest was NOAF within 30 days following TAVR. We used a 2-step statistical model including random forest for variable importance ranking, followed by multivariable logistic regression for predictors of highest importance. Model discrimination was assessed by using the C-statistic to compare the performance of the models with and without imaging.

RESULTS

Forty-seven (5.0%) of 935 patients without pre-existing atrial fibrillation (AF) experienced NOAF. Patients with pre-existing AF had the largest left atrial volume index at 76.3 ± 28.6 cm3/m2 followed by NOAF at 68.1 ± 26.6 cm3/m2 and then no AF at 57.0 ± 21.7 cm3/m2 (P < 0.001). Multivariable regression identified the following risk factors in association with NOAF: left atrial volume index ≥76 cm2 (OR: 2.538 [95% CI: 1.165-5.531]; P = 0.0191), body mass index <22 kg/m2 (OR: 4.064 [95% CI: 1.500-11.008]; P = 0.0058), EATv (OR: 1.007 [95% CI: 1.000-1.014]; P = 0.043), aortic annulus area ≥659 mm2 (OR: 6.621 [95% CI: 1.849-23.708]; P = 0.004), and sinotubular junction diameter ≥35 mm (OR: 3.891 [95% CI: 1.040-14.552]; P = 0.0435). The C-statistic of the model was 0.737, compared with 0.646 in a model that excluded imaging variables.

CONCLUSIONS

Underlying cardiac structural differences derived from cardiac imaging may be useful in predicting NOAF following transfemoral TAVR, independent of other clinical risk factors.

Antithrombotic Therapy in Patients Undergoing Transcatheter Aortic Valve Implantation

Transcatheter aortic valve implantation (TAVI) now represents the mainstay of treatment for severe aortic stenosis. Owing to its exceptional procedural efficacy and safety, TAVI has been extended to include patients at lower surgical risk, thus now encompassing a diverse patient population receiving this treatment. Yet, long-term outcomes also depend on optimal medical therapy for secondary vascular prevention, with antithrombotic therapy serving as the cornerstone. Leveraging data from multiple randomized controlled trials, the current guidelines generally recommend single antithrombotic therapy, with either single antiplatelet therapy (SAPT) or oral anticoagulation (OAC) alone in those patients without or with atrial fibrillation, respectively. Yet, individualization of this pattern, as well as specific case uses, may be needed based on individual patient characteristics and concurrent procedures. This review aims to discuss the evidence supporting antithrombotic treatments in patients treated with TAVI, indications for a standardized treatment, as well as specific considerations for an individualized approach to treatment.

Health-related quality of life following TAVI or cardiac surgery in patients at intermediate and low risk: a systematic review and meta-analysis

Recent randomised trials have shown that clinical outcomes with transcatheter aortic valve implantation (TAVI) are non-inferior to surgical aortic valve replacement (SAVR) in patients with symptomatic aortic stenosis at intermediate to low risk. Health-related quality of life (HrQoL) outcomes in these patient groups remain uncertain. A systematic search of the literature was conducted that included nine trials and 11,295 patients. Kansas City Cardiomyopathy Questionnaire (KCCQ), a heart-failure-specific measure and EuroQol-5D (EQ-5D) (a generic health status tool) changes were the primary outcomes. New York Heart Association (NYHA) classification was the secondary outcome. Improvement in KCCQ scores was greater with TAVI (mean difference (MD)=13.56, 95% confidence interval (CI) 11.67-15.46, p<0.001) at 1 month, as was the improvement in EQ-5D (MD=0.07, 95% CI 0.05-0.08, p<0.001). There was no difference in KCCQ (MD=1.05, 95% CI -0.11 to 2.21, p=0.08) or EQ-5D (MD=-0.01, 95% CI -0.03 to 0.01), p=0.37) at 12 months. NYHA functional class 3/4 was lower in patients undergoing TAVI at 1 month (MD=0.51, 95% CI 0.34-0.78, p=0.002), but there was no difference at 12 months (MD=1.10; 95% CI 0.87-1.38, p=0.43). Overall, TAVI offers early benefit in HRQoL outcomes compared with SAVR, but they are equivalent at 12 months.

Incidence and clinical impact of tachyarrhythmic events following transcatheter aortic valve replacement: A review

Transcatheter aortic valve replacement (TAVR) is well established for treating severe symptomatic aortic stenosis. Whereas broad information on the epidemiology, clinical implications, and management of bradyarrhythmias after TAVR is available, data about tachyarrhythmic events remain scarce. Despite the progressively lower risk profile of TAVR patients and the improvement in device characteristics and operator skills, approximately 10% of patients develop new-onset atrial fibrillation (NOAF) after TAVR. The proportion of patients in whom NOAF actually corresponds to previously undiagnosed silent atrial fibrillation (AF) has not been properly determined. The transapical approach, the need for pre- or post- balloon dilation, and the presence of periprocedural complications have been associated with a higher risk of NOAF. Older age, left atrial volume, or worse functional class are patient-derived risk factors shared with preprocedural AF. NOAF after TAVR has been associated with poorer survival and a higher incidence of cerebrovascular events. However, patient management differs markedly among different centers, especially with regard to anticoagulation in patients with short-duration AF episodes detected in the periprocedural setting and in cases of silent NOAF detected during continuous electrocardiographic (ECG) monitoring. Evidence about ventricular arrhythmias is even more scarce than for AF. Some case reports of sudden cardiac death after TAVR in patients with a pacemaker have identified ventricular tachycardia or ventricular fibrillation in device interrogation. TAVR has been shown to reduce the arrhythmic burden, but a significant proportion of patients (16%) present with complex premature ventricular complex arrhythmias within the year after TAVR. Whether these events are related to poorer outcomes is unknown. Continuous ECG monitoring after TAVR may help describe the frequency, risk factors, and prognostic implications of tachyarrhythmias in this population.

Antithrombotic Therapy Following Transcatheter Aortic Valve Replacement

Due to a large technical improvement in the past decade, transcatheter aortic valve replacement (TAVR) has expanded to lower-surgical-risk patients with symptomatic and severe aortic stenosis. While mortality rates related to TAVR are decreasing, the prognosis of patients is still impacted by ischemic and bleeding complications, and defining the optimal antithrombotic regimen remains a priority. Recent randomized control trials reported lower bleeding rates with an equivalent risk in ischemic outcomes with single antiplatelet therapy (SAPT) when compared to dual antiplatelet therapy (DAPT) in patients without an underlying indication for anticoagulation. In patients requiring lifelong oral anticoagulation (OAC), the association of OAC plus antiplatelet therapy leads to a higher risk of bleeding events with no advantages on mortality or ischemic outcomes. Considering these data, guidelines have recently been updated and now recommend SAPT and OAC alone for TAVR patients without and with a long-term indication for anticoagulation. Whether a direct oral anticoagulant or vitamin K antagonist provides better outcomes in patients in need of anticoagulation remains uncertain, as recent trials showed a similar impact on ischemic and bleeding outcomes with apixaban but higher gastrointestinal bleeding with edoxaban. This review aims to summarize the most recently published data in the field, as well as describe unresolved issues.

Incidence of Early Atrial Fibrillation After Transcatheter versus Surgical Aortic Valve Replacement: A Meta-Analysis of Randomized Controlled Trials

Background

Post-operative atrial fibrillation (POAF) is common after aortic valve replacement (AVR) and is associated with worse outcomes. We performed a meta-analysis of randomized controlled trials comparing Surgical Aortic Valve Replacement (SAVR) and Transcatheter Aortic Valve Replacement (TAVR) for incidence of POAF at 30 days.

Methods

We searched databases from 1/1/1990 to 1/1/2020 for randomized studies comparing TAVR and SAVR. POAF was defined as either worsening or new-onset atrial fibrillation. Random effects model was used to estimate the risk of POAF with TAVR vs SAVR in all trials, and in subgroups (low, intermediate, high risk, and in self-expandable vs balloon expandable valves). Sensitivity analysis was performed including only studies reporting new-onset atrial fibrillation.

Results

Seven RCTs were identified that enrolled 7,934 patients (3,999 to TAVR and 3,935 to SAVR). The overall incidence of POAF was 9.7% after TAVR and 33.3% after SAVR. TAVR was associated with a lower risk of POAF compared with SAVR (OR 0.21 [0.18-0.24]; P < 0.0001). Compared with SAVR, TAVR was associated with a significantly lower risk of POAF in the high-risk cohort (OR 0.37 [0.27-0.49]; P < 0.0001), in the intermediate-risk cohort (OR 0.23 [0.19-0.28]; P < 0.0001), low-risk cohort (OR 0.13 [0.10-0.16]; P < 0.0001). Sensitivity analysis of 4 trials including only new-onset POAF showed similar summary estimates (OR 0.21, 95% CI [0.18-0.25]; P< 0.0001).

Conclusions

TAVR is associated with a significantly lower risk of post-operative atrial fibrillation compared with SAVR in all strata. Further studies are needed to identify the contribution of post-operative atrial fibrillation to the differences in clinical outcomes after TAVR and SAVR.