An Economic Evaluation of a Streamlined Day-Case Atrial Fibrillation Ablation Protocol and Conventional Cryoballoon Ablation versus Antiarrhythmic Drugs in a UK Paroxysmal Atrial Fibrillation Population

BACKGROUND AND AIMS

Symptom control for atrial fibrillation can be achieved by catheter ablation or drug therapy. We assessed the cost effectiveness of a novel streamlined atrial fibrillation cryoballoon ablation protocol (AVATAR) compared with optimised antiarrhythmic drug (AAD) therapy and a conventional catheter ablation protocol, from a UK National Health Service (NHS) perspective.

METHODS

Data from the AVATAR study were assessed to determine the cost effectiveness of the three protocols in a two-step process. In the first stage, statistical analysis of clinical efficacy outcomes was conducted considering either a three-way comparison (AVATAR vs. conventional ablation vs. optimised AAD therapies) or a two-way comparison (pooled ablation protocol data vs. optimised AAD therapies). In the second stage, models assessed the cost effectiveness of the protocols. Costs and some of the clinical inputs in the models were derived from within-trial cost analysis and published literature. The remaining inputs were derived from clinical experts.

RESULTS

No significant differences between the ablation protocols were found for any of the clinical outcomes used in the model. Results of a within-trial cost analysis show that AVATAR is cost-saving (£1279 per patient) compared with the conventional ablation protocol. When compared with optimised AAD therapies, AVATAR (pooled conventional and AVATAR ablation protocols efficacy) was found to be more costly while offering improved clinical benefits. Over a lifetime time horizon, the incremental cost-effectiveness ratio of AVATAR was estimated as £21,046 per quality-adjusted life-year gained (95% credible interval £7086-£71,718).

CONCLUSIONS

The AVATAR streamlined protocol is likely to be a cost-effective option versus both conventional ablation and optimised AAD therapy in the UK NHS healthcare setting.

Ablation versus anti-arrhythmic therapy for reducing all hospital episodes from recurrent atrial fibrillation: a prospective, randomized, multi-centre, open label trial

AIMS

There is rising healthcare utilization related to the increasing incidence and prevalence of atrial fibrillation (AF) worldwide. Simplifying therapy and reducing hospital episodes would be a valuable development. The efficacy of a streamlined AF ablation approach was compared to drug therapy and a conventional catheter ablation technique for symptom control in paroxysmal AF.

METHODS AND RESULTS

We recruited 321 patients with symptomatic paroxysmal AF to a prospective randomized, multi-centre, open label trial at 13 UK hospitals. Patients were randomized 1:1:1 to cryo-balloon ablation without electrical mapping with patients discharged same day [Ablation Versus Anti-arrhythmic Therapy for Reducing All Hospital Episodes from Recurrent (AVATAR) protocol]; optimization of drug therapy; or cryo-balloon ablation with confirmation of pulmonary vein isolation and overnight hospitalization. The primary endpoint was time to any hospital episode related to treatment for atrial arrhythmia. Secondary endpoints included complications of treatment and quality-of-life measures. The hazard ratio (HR) for a primary endpoint event occurring when comparing AVATAR protocol arm to drug therapy was 0.156 (95% CI, 0.097-0.250; P < 0.0001 by Cox regression). Twenty-three patients (21%) recorded an endpoint event in the AVATAR arm compared to 76 patients (74%) within the drug therapy arm. Comparing AVATAR and conventional ablation arms resulted in a non-significant HR of 1.173 (95% CI, 0.639-2.154; P = 0.61 by Cox regression) with 23 patients (21%) and 19 patients (18%), respectively, recording primary endpoint events (P = 0.61 by log-rank test).

CONCLUSION

The AVATAR protocol was superior to drug therapy for avoiding hospital episodes related to AF treatment, but conventional cryoablation was not superior to the AVATAR protocol. This could have wide-ranging implications on how demand for AF symptom control is met.

TRIAL REGISTRATION

Clinical Trials Registration: NCT02459574.

Rationale and study design of the MINERVA study: Multicentre Investigation of Novel Electrocardiogram Risk markers in Ventricular Arrhythmia prediction-UK multicentre collaboration

INTRODUCTION

The purpose of this study is to assess the ability of two new ECG markers (Regional Repolarisation Instability Index (R2I2) and Peak Electrical Restitution Slope) to predict sudden cardiac death (SCD) or ventricular arrhythmia (VA) events in patients with ischaemic cardiomyopathy undergoing implantation of an implantable cardioverter defibrillator for primary prevention indication.

METHODS AND ANALYSIS

Multicentre Investigation of Novel Electrocardiogram Risk markers in Ventricular Arrhythmia prediction is a prospective, open label, single blinded, multicentre observational study to establish the efficacy of two ECG biomarkers in predicting VA risk. 440 participants with ischaemic cardiomyopathy undergoing routine first time implantable cardioverter-defibrillator (ICD) implantation for primary prevention indication are currently being recruited. An electrophysiological (EP) study is performed using a non-invasive programmed electrical stimulation protocol via the implanted device. All participants will undergo the EP study hence no randomisation is required. Participants will be followed up over a minimum of 18 months and up to 3 years. The first patient was recruited in August 2016 and the study will be completed at the final participant follow-up visit. The primary endpoint is ventricular fibrillation or sustained ventricular tachycardia >200 beats/min as recorded by the ICD. The secondary endpoint is SCD. Analysis of the ECG data obtained during the EP study will be performed by the core lab where blinding of patient health status and endpoints will be maintained.

ETHICS AND DISSEMINATION

Ethical approval has been granted by Research Ethics Committees Northern Ireland (reference no. 16/NI/0069). The results will inform the design of a definitive Randomised Controlled Trial (RCT). Dissemination will include peer reviewed journal articles reporting the qualitative and quantitative results, as well as presentations at conferences and lay summaries.

TRIAL REGISTRATION NUMBER

NCT03022487.

The inaugural meeting of the Africa Heart Rhythm Association (AFHRA)

Cardiorhythm Africa, the inaugural conference of AFHRA, was conceived during the biennial PASCAR congress held in Johannesburg in November 2019, with the ambition to be the largest ever pan-African conference focused purely on arrhythmia. Significant aims were to (1) bring together arrhythmia specialists from across Africa and from the diaspora; and (2) announce the newly formed African Heart Rhythm Association (AFHRA), an affiliate organisation of PASCAR formed from the amalgamation of the Cardiac Pacing and Arrhythmias taskforces. The meeting held in Nairobi (29-31 January 2020) was organised to provide a focus on resource-constrained arrhythmia management within the African context and novel/advanced and potentially home-grown solutions. There was full representation from all five PASCAR regions (North, East, West, Central and Southern Africa). This report summarises the scope and perspective of the first Cardiorhythm Africa meeting and presents the future directions for this annual meeting.

Cryoablation for persistent and longstanding persistent atrial fibrillation: results from a multicentre European registry

Aims

Although cryoballoon pulmonary vein isolation is a well-established treatment for paroxysmal atrial fibrillation (AF), it’s role in persistent AF is unclear. We examined procedural success and long-term outcomes of cryoablation in persistent and longstanding persistent AF.

Methods and results

International multicentre registry from three UK and eight European centres. Consecutive patients undergoing cryoablation for persistent AF included. Procedural data, complications, and follow-up were prospectively recorded. Patients were followed-up at 3, 6, and 12 months with an electrocardiogram with open access to arrhythmia nurses thereafter. Ambulatory monitoring was dictated by symptoms. Success was defined as freedom from AF or atrial tachycardia lasting &gt;30 s off antiarrhythmic drugs (AADs). Six hundred and nine consecutive cryoablation procedures. Mean procedure and fluoroscopy times were 95 ± 65 and 13 ± 10 min. Single procedure success rates were 368/602 (61%) off AADs over a median of 2.4 (1.0–4.0) years. Arrhythmia-free survival off AADs was 64% and 57% for persistent and longstanding persistent AF at 24 months of follow-up (P = 0.02). Rate of repeat ablations was 20% in persistent and 32% in longstanding persistent AF (P = 0.006). Cox regression analyses showed a significant association between duration of AF and left atrial diameter and arrhythmia recurrence [hazard ratio (HR) 1.05, P-value 0.01 and HR 1.02, P-value 0.004].

Conclusion

Cryoablation for persistent AF is safe, fast and has good outcomes at long-term follow-up. Cryoablation is reasonable as a first line option for these patients. Short procedure times may help increase capacity of cardiac units to meet the rising demand for AF ablation. Randomised control trials are needed to compare outcomes with different techniques.

Ablation versus Anti-Arrhythmic Therapy for Reducing All Hospital Episodes from Recurrent Atrial Fibrillation (AVATAR-AF): Design and rationale

Atrial Fibrillation (AF) ablation using the cryoballoon is effective at reducing symptomatic AF episodes. The prevalence of AF is increasing with the aging population and access to such treatment would be enhanced by reducing the resource requirements. Relinquishing electrical mapping of the pulmonary veins (PV) removes the need for PV catheters, electrical recording equipment and staff trained in using this equipment. Moreover, the majority of complications are peri-procedural so overnight hospitalization maybe unnecessary. We tested this streamlined approach to AF ablation against medical therapy using the endpoint of time to all hospital episodes. METHODS: The AVATAR-AF study is a prospective, multicenter, randomized controlled trial testing the primary hypothesis that AF ablation done without PV mapping or overnight hospitalization is more effective than anti-arrhythmic drugs at reducing all hospital episodes related to recurrent atrial arrhythmias. We included a third arm to test a secondary hypothesis that confirming PV entrance block as per consensus guidelines can improve outcomes. Three hundred twenty-one patients with documented paroxysmal AF will be randomized in a 1:1:1 manner to one of three investigation arms: (1) AVATAR protocol cryoballoon ablation without assessment of acute PV isolation or overnight hospitalization; (2) medical therapy with anti-arrhythmic drugs; or (3) conventional cryoballoon ablation with assessment of acute PV isolation. The primary endpoint is defined as the time to all hospital episodes (including outpatient consultation) related to treatment for atrial arrhythmia. CONCLUSION: The AVATAR-AF study will determine whether the resource utilization for AF ablation can be reduced whilst maintaining superiority over medical therapy.

Current Venous Thromboembolism Prevention Practices Following Endovascular Electrophysiological Procedures in the UK: A retrospective study

Objectives

This study aimed to evaluate the incidence of venous thromboembolism (VTE) cases at the Leeds General Infirmary, Leeds, UK, as well as to survey current VTE practices and preventative strategies at other UK-based electrophysiology (EP) centres.

Methods

This retrospective study involved all patients who underwent EP studies at Leeds General Infirmary from January 2014 to December 2016. In addition, a telephone survey was conducted of 35 other UK-based EP centres.

Results

Of 1,020 patients who underwent EP studies at Leeds General Infirmary, 0.3% developed a post-procedural VTE. In addition, 28 other EP centres were surveyed (response rate: 80%), of which 18% reported VTE cases in the last two years. There were wide variations in VTE prevention strategies and the use of post-procedural thromboprophylaxis.

Conclusion

Despite the low incidence of VTE cases, many UK centres continue to experience this complication with no consensus on optimal preventative strategies. As current VTE guidelines do not recommend antithrombotics after EP studies, further research is needed.

Optimal dosing of angiotensin-converting enzyme inhibitors and β-blockers for acute coronary syndrome: up-titration remains a challenge

Objectives

Suboptimal dosing of angiotensin-converting enzyme inhibitors and β-blockers limits the mortality benefit for acute coronary syndrome patients. Recent National Institute for Health and Care Excellence (NICE) guidelines emphasise prompt initiation and up-titration from inpatient to community care to achieve this. The aim of this study was to assess the impact of simple interventions on inpatient and community up-titration of bisoprolol and ramipril for acute coronary syndrome patients admitted to Leeds General Infirmary.

Methods

An initial prospective audit of 37 acute coronary syndrome patients admitted to Leeds General Infirmary in January 2013 assessed inpatient up-titration of bisoprolol and ramipril, discharge advice and doses at 6 weeks after discharge. Following a collective multidisciplinary effort with education, posters and discharge advice templates, a re-audit of 34 acute coronary syndrome patients admitted from November to December 2014 assessed the impact of these interventions. The independent samples t test was used to compare the mean difference between doses of ramipril and bisoprolol from initiation to discharge to dose at 6 weeks after discharge before and after intervention.

Results

There was a statistically significant improvement in the mean difference from initiation to discharge dose for both ramipril and bisoprolol (p=0.012 and p=0.017, respectively). However, there was little difference in community up-titration despite a 68% improvement in discharge advice.

Conclusions

Simple multidisciplinary interventions improved inpatient up-titration of ramipril and bisoprolol but continued up-titration to achieve the target doses remains a challenge in primary care. Acute coronary syndrome patients are precluded from maximum mortality benefit due to suboptimal dosing after discharge.

Characterization of Fractionated Atrial Electrograms Critical for Maintenance of Atrial Fibrillation

Background—

Whether ablation of complex fractionated atrial electrograms (CFAE) modifies atrial fibrillation (AF) by eliminating drivers or atrial debulking remains unknown. This randomized study aimed to determine the effect of ablating different CFAE morphologies compared with normal electrograms (ie, debulking normal tissue) on the cycle length of persistent AF (AFCL).

Methods and Results—

After pulmonary vein isolation left and right atrial CFAE were targeted, until termination of AF or abolition of CFAE before DC cardioversion. Ten-second electrograms were classified according to a validated scale, with grade 1 being most fractionated and grade 5 normal. Patients were randomly assigned to have CFAE grades eliminated sequentially, from grade 1 to 5 (group 1) or grade 5 to 1 (group 2). An increase in AFCL (mean of left and right atrial appendage) ≥5 ms after a lesion was regarded as significant. CFAE (n=968) were targeted in 20 patients. AFCL increased after targeting 51±35% of grade 1 CFAE, 30±15% grade 2, 12±5% grade 3, 33±12% grade 4, and 8±15% grade 5 CFAE ( P <0.01 for grades 1, 2, and 4 versus 5; 3 versus 5, not significant). The proportion of lesions causing AFCL prolongation was unaffected by the order in which CFAE were targeted.

Conclusions—

Targeting CFAE is not simply atrial debulking. Ablating certain grades of CFAE increases AFCL, suggesting they are more important in maintaining AF.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00894400.

South Asian or Afro-Caribbean ethnicity is not associated with altered 1 min heart rate recovery estimates in suspected coronary artery disease patients

Heart rate recovery following a Bruce exercise protocol provides prognostic information on survival. We investigated the impact of ethnicity on HRR in 271 consecutive patients being assessed for CAD in three main ethnic groups (Caucasian (C); South Asian (SA); Afro-Caribbean (AC)). Our sample contained greater referral of younger, male South Asian subjects than would be expected on the basis of census data. The AC group had a low frequency of typical ischaemic pain. The SA sub-group, despite greater prevalence of diabetes, had marginally better HRR and a more preserved response to exercise. Multiple regression analysis revealed that age and not ethnicity was the main independent predictor of HRR (p=0.007) with all three ethnic sub-groups having a similar range of exercise time. There was no evidence of under referral of ethnic minorities. Ethnic effects in raw HRR data are most likely confounded by age.

Abnormal soluble CD40 ligand and C-reactive protein concentrations in hypertension: relationship to indices of angiogenesis

BACKGROUND

Abnormal inflammation, platelets and angiogenesis are involved in the pathophysiology of cardiovascular disease (CVD).

OBJECTIVE

To test the hypothesis that concentrations of high sensitive C-reactive protein (CRP, an index of inflammation) and soluble CD40 ligand (sCD40L, an index of platelet activation) would be abnormal in hypertension, and in turn, be related to plasma indices of angiogenesis, the angiopoietins-1 and -2, and vascular endothelial growth factor (VEGF), in addition to the presence or absence of CVD.

METHODS

Using a cross-sectional approach, we measured plasma concentrations of CRP, sCD40L, VEGF, and angiopoietins-1 and -2 in 147 patients with hypertension (85 with a history of CVD event/s, 62 CVD event-free) and 68 age- and sex-matched healthy controls.

RESULTS

Concentrations of sCD40L (P = 0.039), CRP (P < 0.001), angiopoietin-1 (P < 0.001), angiopoietin-2 (P = 0.003) and VEGF (P < 0.001) were all greater amongst hypertensive patients than in controls. There were no significant differences in sCD40L and VEGF concentrations between hypertensive individuals with and without CVD events, but CRP and angiopoietin-1 concentrations were significantly greater amongst those with CVD events. On multiple regression analysis, sCD40L was associated with angiopoietin-2 (P = 0.01) and VEGF (P = 0.007) in hypertensive individuals, but no such associations were found within the healthy control group.

CONCLUSION

In patients with hypertension, sCD40L was associated with increased circulating markers of abnormal angiogenesis (angiopoietin-2, VEGF). The interaction between sCD40L and angiogenesis may contribute to the pathophysiology of CVD in hypertension.

Circulating endothelial cells, von Willebrand factor, interleukin-6, and prognosis in patients with acute coronary syndromes

Markers of inflammation (eg, interleukin-6 [IL-6]), and endothelial perturbation (von Willebrand factor [VWF], circulating endothelial cells [CECs]) are altered in acute coronary syndromes (ACS). We hypothesized that CECs and IL-6 levels during the first 48 hours of ACS would predict 30-day and 1-year major cardiovascular end points (MACE). A total of 156 patients with ACS were included. Blood was drawn on admission (baseline) and 48 hours later for plasma VWF, IL-6 (both enzyme-linked immunosorbent assay [ELISA]), and CECs (CD146 immunomagnetic separation). CEC phenotyping was performed by indirect immunoperoxidase staining. At 30 days, 48 patients had a MACE, a predicted by baseline and 48-hour CECs and IL-6 levels, 48-hour VWF levels, and by the “admission–48 hour change” (Δ) in CECs, VWF, and IL-6 (all P = .002). On multivariate analysis, 48-hour CECs (P &lt; .001) were the strongest predictor of MACE, followed by ΔIL-6 (P = .01) and ΔVWF (P = .048); 48-hour CECs were the only predictor of death (P = .007). At 1 year, 65 patients had MACE, predicted by 48-hour CECs and ΔIL-6 levels (P &lt; .001); age (P = .046) and 48-hour CECs (P &lt; .001) were the only predictors of death. CECs stained 93% positive for endothelial nitric oxide synthase (eNOS) but were less than 1% positive for CD34, CD36, and CD45 and less than 3% for CD31. Like raised VWF, abnormal CECs and IL-6 levels during the first 48 hours of ACS were strongly associated with 30-day MACE. CECs at 48 hours were the only independent predictor of both death and MACE at 30 days and 1 year, indicating the crucial role of endothelial/vascular damage in ACS pathophysiology.