The role of CHA2DS2-VASc score in predicting atrial fibrillation recurrence in patients undergoing pulmonary vein isolation with cryoballoon ablation

Funding Acknowledgements

Type of funding sources: None.

Background

Pulmonary vein isolation by cryoablation (PVI-C) is a standard therapy for the treatment of atrial fibrillation (AF) with high safety and efficacy profiles. The CHA2DS2 -VASc score is also a well-established predictor of AF stroke. Importantly, the role of CHA2DS2-VASc score is still unknown regarding the long-term clinical outcomes following PVI-C.

Purpose

The aim of this analysis is to evaluate the role of CHA2DS2-VASc score in predicting AF recurrence during long term follow up after PVI-C.

Methods

Patients with recurrent and symptomatic AF underwent an index PVI-C. Data were collected prospectively in the framework of 1STOP ClinicalService® project. Patients were categorized into two groups Low risk (LR) and high risk (HR) (CHA2DS2-VASc score = 0-1 and CHA2DS2 -VASc score ≥2, respectively).

Results

Out of 3313 patients, 1910 (57.6%) had CHA2DS2-VASc score = 0-1, while 1403 (42.3%) were in the HR score group (CHA2DS2 -VASc score ≥2). As expected, patient baseline characteristics were significantly different between the two cohorts including: age, sex, BMI, percentage of paroxysmal AF, history of stroke, diabetes, ischemic cardiomyopathy. On the contrary, procedural times and the incidence of acute complications were comparable between the two groups. The 36-month freedom from AF after a single procedure was 72.5% (95% CI 69.8% - 75.0%) in the LR group and 65.9% (62.3% - 69.2%) in the HR score group (HR: 1.26, 95% CI 1.08-1.47, p= 0003, Figure 1). At multivariate analysis, higher CHA2DS2 -VASc score was still a significant predictor of the risk of AF recurrence [HR: 1.33 (1.10 - 1.60, p=0.003]

Conclusions

PVI-C is highly effective in the treatment of AF over the long term. A CHA2DS2 -VASc score ≥2 is an independent predictor of AF recurrence during the follow-up and should be taken into account in the clinical management after the index procedure.

Comparison of hepatitis C virus subtyping by ns5b sequencing with 5'utr based methods

AIM

We compared Hepatitis C virus (HCV) genotyping by direct sequencing of the non-structural 5b region (NS5b) and a commercial PCR/hybridization method based on the conserved 5´-untranslated region (5'UTR).

METHODS

One hundred twenty HCV containing plasma samples were analyzed by NS5b sequencing with focus on samples with undetermined results or 1b subtype identification in the used combination of Cobas® AmpliPrep/Cobas® TaqMan96® PCR and subsequent Versant® HCV Genotype 2.0 Assay (LiPA).

RESULTS

There was 100% concordance between the two methods for genotyping but only 83% for subtyping. Seventeen samples were designated 1b by hybridization but subtype 1a by NS5b sequencing. This is a general 5'UTR problem as the discordant results were additionally confirmed by 5'UTR sequencing. Thus our routine combination not only misclassified 38.6% of subtype 1a isolates as 1b but in contrast to NS5b sequencing was unable to discriminate between subtypes 2a/c, or 4a/c/d and also failed on a newly described subtype (10a/3k). [corrected].

CONCLUSIONS

[corrected] The applied 5'UTR methods allow the rapid determination of HCV genotypes but failed to correctly identify the subtype in many samples. This has implications for epidemiological studies or forensic evaluation of chains of infection and NS5b sequencing therefore is our method of choice under those circumstances.