Transvenous Cryoablation Reduces Platelet Activation During Pulmonary Vein Ablation Compared with Radiofrequency Energy in Patients with Atrial Fibrillation

Multi-Omics Signatures Link to Ticagrelor Effects on Vascular Function in Patients With Acute Coronary Syndrome

BACKGROUND

Long-term antiplatelet agents including the potent P2Y12 antagonist ticagrelor are indicated in patients with a previous history of acute coronary syndrome. We sought to compare the effect of ticagrelor with that of aspirin monotherapy on vascular endothelial function in patients with prior acute coronary syndrome.

METHODS

This was a prospective, single center, parallel group, investigator-blinded randomized controlled trial. We randomized 200 patients on long-term aspirin monotherapy with prior acute coronary syndrome in a 1:1 fashion to receive ticagrelor 60 mg BD (n=100) or aspirin 100 mg OD (n=100). The primary end point was change from baseline in brachial artery flow-mediated dilation at 12 weeks. Secondary end points were changes to platelet activation marker (CD41_62p) and endothelial progenitor cell (CD34/133) count measured by flow cytometry, plasma level of adenosine, IL-6 (interleukin-6) and EGF (epidermal growth factor), and multi-omics profiling at 12 weeks.

RESULTS

After 12 weeks, brachial flow-mediated dilation was significantly increased in the ticagrelor group compared with the aspirin group (ticagrelor: 3.48±3.48% versus aspirin: -1.26±2.85%, treatment effect 4.73 [95% CI, 3.85-5.62], P<0.001). Nevertheless ticagrelor treatment for 12 weeks had no significant effect on platelet activation markers, circulating endothelial progenitor cell count or plasma level of adenosine, IL-6, and EGF (all P>0.05). Multi-omics pathway assessment revealed that changes in the metabolism and biosynthesis of amino acids (cysteine and methionine metabolism; phenylalanine, tyrosine, and tryptophan biosynthesis) and phospholipids (glycerophosphoethanolamines and glycerophosphoserines) were associated with improved brachial artery flow-mediated dilation in the ticagrelor group.

CONCLUSIONS

In patients with prior acute coronary syndrome, ticagrelor 60 mg BD monotherapy significantly improved brachial flow-mediated dilation compared with aspirin monotherapy and was associated with significant changes in metabolomic and lipidomic signatures.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT03881943.

Measurements of immature platelet fraction and inflammatory markers in atrial fibrillation patients - Does persistency or ablation affect results?

PURPOSE

Atrial fibrillation (AF) is associated with platelet hyperactivity and a higher proportion of immature platelets. We aimed to examine whether immature platelet fraction (IPF) and inflammatory markers differ between AF types and whether they are affected by ablation.

METHODS

A prospective study included patients with atrial fibrillation/flutter (AFL). We excluded patients with hematologic, inflammatory, or acute coronary states. Blood samples for IPF, white blood cells (WBC), neutrophil-to-lymphocyte ratio (NLR), and C-reactive protein (CRP) were collected at baseline, within one-hour postablation in those undergoing ablations, and the day after ablation. IPF was measured by an autoanalyzer (Sysmex 2100 XE).

RESULTS

One hundred and four patients were included (paroxysmal AF-63, persistent AF-36, AF and AFL-7, AFL alone-5), (Mean age 67.7 ± 12.8 years, 54.8% male, CHA₂ D₂ -VASC₂ 3.2 ± 1.8). Seventy-two patients underwent ablation (cryoballoon AF ablation-60, AFL radiofrequency ablation-5, both-7). There was no difference between paroxysmal and persistent AF regarding baseline markers. There was a significant change in the following parameters after ablation: WBC (baseline 6.9 ± 2.0, 1-h post 8.0 ± 2.4, and 1-day post 9.0 ± 2.8 ×10⁹ /L), NLR (2.9 ± 2.2, 3.0 ± 2.4, 4.2 ± 2.9, respectively), and CRP (3.6 ± 3.7, 3.6 ± 3.5, 12.4 ± 9.0 mg/L, respectively) (P < .05 for all). However, there were no differences in immature platelet count (8.6 ± 4.8, 8.5 ± 4.9, 8.4 ± 5.2 ×10⁹ /L) or IPF (4.6 ± 3.2, 4.7 ± 3.3, 4.9 ± 3.6%) from baseline to postablation (p = NS).

CONCLUSIONS

AF persistency does not affect IPF and inflammation. In patients undergoing cryoablation of AF, there is a postablation inflammatory process; however, platelet activation is probably not affected.

Comparative efficacy and safety of catheter ablation interventions for atrial fibrillation: comprehensive network meta-analysis of randomized controlled trials

PURPOSE

Point-by-point radiofrequency (RF) ablation has been the cornerstone of pulmonary vein isolation (PVI) for patients with atrial fibrillation (AF); however, it remains a complex and time-consuming procedure. Many novel AF catheter ablation (CA) techniques have been introduced, but whether they represent valuable alternatives remains controversial. Thus, we conducted a network meta-analysis to comprehensively evaluate the efficacy and safety of different CA interventions.

METHODS

We systematically searched several databases (Embase, PubMed, the Cochrane Library, and ClinicalTrials.gov ) from inception to March, 2020. The primary outcomes of interest were freedom from atrial tachyarrhythmia (AT) and procedure-related complications; secondary outcomes included procedure time and fluoroscopy time.

RESULTS

Finally, 33 randomized controlled trials (RCTs) with a total of 4801 patients were enrolled. No significant differences were found among the different interventions in terms of primary efficacy or safety outcomes. PVAC was most likely to have the shortest procedure time (Prbest = 61.5%) and nMARQ the shortest fluoroscopy time (Prbest = 60.6%); compared with conventional irrigated RF (IRF) ablation, cryoballoon ablation (CBA) showed comparable clinical efficacy and safety; CBA with second-generation CB (CB2) had a significantly shorter procedure time than IRF with contact force technology (CF-IRF) (WMD = - 20.75; p = 0.00).

CONCLUSION

There is insufficient evidence to suggest that one CA technique is superior to another. However, PVAC may be associated with a shorter procedural duration, and the CB2 catheters also seemed to reduce the procedure time compared with that of CF-IRF. Further large-scale studies are warranted to compare the available CA techniques and provide an up-to-date optimum recommendation.

Uninterrupted use of direct oral anticoagulants versus vitamin K antagonists for catheter ablation of atrial fibrillation with PVAC gold: incidence of silent cerebral microembolic events

BACKGROUND

Silent cerebral microembolic events (SCE) after duty-cycled ablation of atrial fibrillation using PVAC have been detected by cerebral magnet resonance imaging (MRI) in a substantial number of patients. The purpose of this study was to investigate if uninterrupted oral anticoagulation with non-vitamin K antagonists (NOACs) compared with vitamin K antagonists (VKA) affects the incidence of SCE after pulmonary vein isolation (PVI) using PVAC Gold.

METHODS

Eighty-four consecutive patients (62 ± 15 years, 58% male) undergoing a first PVI were prospectively enrolled. Of these, 42 were on VKA and 42 on uninterrupted NOAC treatment. An activated clotting time (ACT) ≥ 350 s was targeted for ablation.

RESULTS

Cerebral MRI the day after PVI revealed acute diffusion-weighted positive lesions in 11/42 (26%) VKA compared with 14/42 (33%) in NOAC patients (p = 0.634). No differences were found for lesion size, number of lesions/patient, and number of lesions indicating cerebral infarction (2.4% for VKA and 4.8% for NOAC patients). Seventy-five percent of NOAC patients with sporadic ACT levels < 300 s during PVI developed SCE compared with 22% of corresponding VKA patients (p = 0.030). VKA and NOAC subgroups with ACT ≥ 350 s had no reduced incidence of SCE compared with ACT 300-350 s.

CONCLUSIONS

A significant, but comparable, number of patients under uninterrupted anticoagulation with VKA or NOACs still experience SCE after PVAC Gold PVI. NOAC patients with sporadic subtherapeutic ACT levels during PVI are at the highest risk for SCE while permanent ACT levels ≥ 350 s did not further reduce the incidence of SCE in both groups.

Meta-Analysis Comparing Cryoballoon Versus Radiofrequency as First Ablation Procedure for Atrial Fibrillation

Pulmonary vein isolation is the cornerstone of atrial fibrillation (AF) ablation. Radiofrequency (RF) represents a standard of care for pulmonary vein isolation, whereas cryoballoon (CB) ablation has emerged as a valid alternative. The aim of our meta-analysis was to explore the efficacy and safety of CB compared with RF as first ablation procedure for AF. We searched the literature for studies that investigated this issue. The primary efficacy outcome was AF recurrence. The safety outcomes were: pericardial effusion, cardiac tamponade, phrenic nerve palsy, vascular complications, and major bleedings. Fourteen randomized controlled studies and 34 observational studies were included in the analysis. A total of 7,951 patients underwent CB ablation, whereas 9,641 received RF ablation. Mean follow-up was 14 ± 7 months. Overall, CB reduced the incidence of AF recurrence compared with RF ablation (relative risk [RR] 0.86; 95% confidence interval [CI] 0.78 to 0.94; p = 0.001), and this result was consistent across different study design and AF type. CB had a significantly higher rate of phrenic nerve palsy, whereas it was related to a lower incidence of pericardial effusion, cardiac tamponade (RR 0.58; 95% CI 0.38 to 0.88; p = 0.011) and vascular complications (RR 0.61; 95% CI 0.48 to 0.77; p <0.001) compared with RF. There was no significant difference in major bleedings between the 2 strategies. CB ablation had a shorter procedural time compared with RF (mean difference -20.76 minutes; p <0.001). In conclusion, considered its efficacy/safety profile and short procedural time, CB ablation represents the preferable option for first AF ablation procedure.

Acute Procedural Complications of Cryoballoon Ablation: A Comprehensive Review

Catheter ablation is increasingly performed for treatment of atrial fibrillation (AF). Balloon based procedures have been developed aiming at safer, easier and more effective treatment as compared to point to point ablation. In the present review article, we aimed to discuss acute procedural complications of cryoballoon ablation.

Myocardial injury during radiofrequency and cryoablation of typical atrial flutter

PURPOSE

Cardiac enzyme elevation after radiofrequency (RF) catheter ablation of atrial flutter (AFL) is common. Some studies found that cryoablation (CRYO) of AFL, compared to RF, is associated with higher levels of troponin, a finding that may indicate CRYO causes a greater amount of myocardial injury than RF. However, other investigations found no significant differences between troponin levels after CRYO versus RF. We have in a randomized study compared the post-procedural troponin I levels in RF and CRYO and the possible relation to procedural outcome and complications.

METHODS

We randomized 153 patients with cavotricuspid isthmus (CTI)-dependent AFL to CRYO or RF (78 CRYO; 75 RF). RF was performed with a 3.5-mm open-irrigated-tip catheter, and CRYO was performed with an 8-mm-tip catheter. Troponin I levels were measured before and 6 h after ablation.

RESULTS

Acute procedural success was achieved in 71/75 patients in the RF and in 72/78 patients in the CRYO. Troponin I levels were significantly elevated in both groups (baseline 0.012, 6th hour 0.35 ng/ml; p < 0.001). Troponin I levels were similar for RF and CRYO. Troponin I levels were higher in patients with acute failure compared to patients with acute success (0.48 ± 0.4 and 0.34 ± 0.16 ng/ml, p = 0.029); however, there was no difference between patients with or without late recurrence. There were no major complications in any group.

CONCLUSION

RF and CRYO for CTI-dependent AFL resulted in similar amounts of procedural myocardial injury. Troponin I levels had no prognostic value for late recurrence of AFL and there were no complications related to high troponin I levels.

Short-Term Heparin Kinetics during Catheter Ablation of Atrial Fibrillation

BACKGROUND

Percutaneous catheter ablation of atrial fibrillation (CA-AF) is a treatment option for symptomatic drug-refractory atrial fibrillation (AF). CA-AF carries a risk for thromboembolic complications that has been minimized by the use of intraprocedural intravenous unfractionated heparin (UFH). The optimal administration of UFH as well as its kinetics are not well established and need to be precisely determined.

METHODS AND RESULTS

A total 102 of consecutive patients suffering from symptomatic drug-refractory AF underwent CA-AF. The mean age was 61 ± 10 years old. After transseptal puncture of the fossa ovalis, weight-adjusted UFH bolus (100 U/kg) was infused. A significant increase in activated clotting time (ACT) was observed from an average value of 100 ± 27 seconds at baseline, to 355 ± 94 seconds at 10 min (T10), to 375 ± 90 seconds at 20 min (T20). Twenty-four patients failed to reach the targeted ACT value of ≥300 seconds at T10 and more than half of these remained with subtherapeutic ACT values at T20. This subset of patients showed similar clinical characteristics and amount of UFH but were more frequently prescribed preprocedural vitamin K1 than the rest of the study population.

CONCLUSIONS

In a typical intervention setting, UFH displays unexpected slow anticoagulation kinetics in a significant proportion of procedures up to 20 minutes after infusion. These findings support the infusion of UFH before transseptal puncture or any left-sided catheterization with early ACT measurements to identify patients with delayed kinetics. They are in line with recent guidelines to perform CA-AF under therapeutic anticoagulation.

Effects of cryoablation and radiofrequency ablation on endothelial and blood clotting activation

Cryoablation (CA) emerged as an alternative procedure to radiofrequency (RF). The aim of this study was to compare haemostatic system alterations in patients undergoing RF or CA for atrioventricular nodal reentrant tachycardia ablation. von Willebrand factor (vWF), spontaneous whole blood platelet aggregation, prothrombin fragment F1 + 2 (F1 + 2), thrombin-antithrombin complex (TAT), plasminogen activator inhibitor type-1 (PAI-1), and clot lysis time (CLT) were determined in 48 patients (27 CA; 21 RF; 19M/29F, mean age 49.6 ± 17.6 years). Blood samples were obtained before the procedure (T0), immediately after (T1), and 24 h later (T2). At T1 both procedures were associated with a significant increase in levels of the endothelial activation marker vWF. At T2 vWF levels were lower in CA than in RF group. No changes in whole blood platelet aggregation before and after ablation procedures were observed. At T1 both groups determined an increase in blood clotting activation markers, F1 + 2, TAT, and DD. At T2 F1 + 2, TAT and DD levels were similar to baseline values. The comparison between RF and CA showed no significant differences in F1 + 2 and TAT levels, whereas at T1 DD levels were higher in CA group than in RF group. Both procedures induced a significant decrease in CLT, whereas no changes in PAI-1 levels were found. There were no significant differences in CLT and PAI-1 levels. The fibrinolytic efficiency analysis showed that at T1 DD/TAT and DD/F1 + 2 ratios were lower in RF group and remained lower in RF than in CA group at T2. CA procedure may be associated with a lower degree of endothelial damage and with a higher fibrinolytic capacity respect to RF.

Atrial Fibrillation and Stroke: Increasing Stroke Risk with Intervention

This article focuses on the important newly recognized appreciation for the paradoxic increase in stroke and transient ischemic attack as a result of intervention meant to treat atrial fibrillation (AF) with the hope of decreasing stroke risk in the long term. The impact of silent cerebral lesions has recently been identified as a potentially major limitation, and the risks with AF ablation, as well as the present understanding of how risk can be minimized, are explained. This article provides a platform for newer study, changes in the way procedures are done, and possibly vascular-based stroke-reduction strategies.

Silent Cerebral Embolism during Atrial Fibrillation Ablation:Pathophysiology, Prevention and Management

Although many efforts have been directed to improve atrial fibrillation transcatheter ablation safety, thromboembolism to the brain remains one of the major complications. In fact several studies have confirmed occurrence of silent cerebral embolic lesions by post-procedure magnetic resonance imaging. The present review will focus on the possible mechanisms leading to silent cerebral embolism in an attempt to provide recommendations holding the potential to reduce the incidence of this clinically relevant complication.

Catheter ablation for paroxysmal and persistent atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is the most common cardiac arrhythmia seen in cardiovascular departments. Treatments include medical interventions and catheter ablation. Due to uncertainties in medical therapies for AF, and the need to continue sinus rhythm, ablation has been recently considered as a viable alternative. Many new ablation methods based on pulmonary vein isolation (PVI) have been developed.

OBJECTIVES

The primary objective of this review was to assess the beneficial and harmful effects of catheter ablation (CA) in comparison with medical treatment in patients with paroxysmal and persistent AF. The secondary objective was to determine the best regimen of CA.

SEARCH METHODS

Searches were run on The Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library Issue 3 2009, MEDLINE (1950 to August 2009), EMBASE (1980 to August 2009), the Chinese Biomedical Literature Database (1978 to August 2009) and the CKNI Chinese Paper Database (1994 to 2009) . Several journals published in Chinese were also handsearched.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in people with paroxysmal and persistent AF treated by any type of CA method. Two reviewers independently selected the trials for inclusion.

DATA COLLECTION AND ANALYSIS

Assessments of risk of bias were performed by two reviewers, and relative risk (RR) and 95% confidence intervals (CI) were used for dichotomous variables. Meta-analysis were performed where appropriate.

MAIN RESULTS

A total of 32 RCTs (3,560 patients) were included. RCTs were small in size and of poor quality.CA compared with medical therapies: seven RCTs indicated that CA had a better effect in inhibiting recurrence of AF [RR 0.27; 95% CI 0.18, 0.41)] but there was significant heterogeneity. There was limited evidence to suggest that sinus rhythm was restored during CA (one small trial: RR 0.28, 95% CI 0.20-0.40), and at the end of follow-up (RR 1.87, 95% CI 1.31-2.67; I(2)=83%). There were no differences in mortality (RR, 0.50, 95% CI 0.04 to 5.65), fatal and non-fatal embolic complication (RR 1.01, 95% CI 0.18 to 5.68) or death from thrombo-embolic events (RR 3.04, 95% CI 0.13 to 73.43).Comparisons of different CAs; 25 RCTs compared CA of various kinds. Circumferential pulmonary vein ablation was better than segmental pulmonary vein ablation in improving symptoms of AF (p<=0.01) and in reducing the recurrence of AF (p<0.01). There is limited evidence to suggest which ablation method was the best.

AUTHORS' CONCLUSIONS

There is limited evidence to suggest that CA may be a better treatment option compared to medical therapies in the management of persistent AF. This review was also unable to recommend the best CA method.

Mechanisms of thrombogenesis in atrial fibrillation: Virchow's triad revisited

Atrial fibrillation is the most common sustained cardiac arrhythmia, which is associated with a high risk of stroke and thromboembolism. Increasing evidence suggests that the thrombogenic tendency in atrial fibrillation is related to several underlying pathophysiological mechanisms. Abnormal changes in flow are evident by stasis in the left atrium, and seen as spontaneous echocontrast. Abnormal changes in vessel walls-essentially, anatomical and structural defects-include progressive atrial dilatation, endocardial denudation, and oedematous or fibroelastic infiltration of the extracellular matrix. Additionally, abnormal changes in blood constituents are well described, and include haemostatic and platelet activation, as well as inflammation and growth factor changes. These changes result in the fulfilment of Virchow's triad for thrombogenesis, and accord with a prothrombotic or hypercoagulable state in this arrhythmia. In this Review, we present an overview of the established and purported mechanisms for thrombogenesis in atrial fibrillation.