Virtual ACC: Ethanol infusion in vein of Marshall improves catheter ablation outcomes 

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Miguel Valderrabano ACC virtual event
Miguel Valderrabano

The infusion of ethanol via the vein of Marshall (VOM), coupled with catheter ablation, leads to improved outcomes for patients with persistent atrial ablation, according to the findings of a study presented by Miguel Valderrabano (Baylor College of Medicine, Houston, USA) at the American College of Cardiology/World Congress of Cardiology’s virtual scientific sessions (ACC.20/WCC Virtual). 

Findings from the Venus TrialVein Of Marshall ethanol infusion for persistent atrial fibrillationwere presented on day two of the virtual conference, which was originally scheduled to take place on 28–30 March in Chicago, USA. 

Opening his presentation, Valderrabano noted that the treatment of persistent AF remains a challenge due to the limited success of catheter ablation, including low singleprocedure success and a frequent need for repeat procedures. Procedural strategies beyond pulmonary vein isolation (PVI) have failed to consistently improve results, he said.  

Valderrabano noted that the VOM contains innervation and AF triggers that can be ablated by retrograde ethanol infusion. Therefore, the study team hypothesised, VOM ethanol and de novo catheter ablation of persistent AF could improve the results of persistent AF ablation, as well as increasing the chances of maintaining normal rhythm. 

The study was designed with a primary endpoint of freedom from AF or atrial tachycardia (AT) of greater than 30 seconds after a single procedure, without anti-arrhythmic drugs, after a three-month period. Secondary endpoints included success after more than one procedure, or with drug-treatment. Patients aged between 18 and 85 years of age, symptomatic of persistent AF, and refractory to at least one antiarrhythmic agent, were eligible for inclusion in the trial. Patients with previous ablation attempts, with a left atrial diameter or volume exceeding 65mm or 200mL, or an ejection fraction greater than 30%, were excluded. 

The study team randomised 343 patients, from 11 healthcare centres, in a 1:1.15 ratio to receive either catheter ablation alone, or catheter ablation combined with VOM ethanol. They predict that in around 15% of the patients randomised to the VOM group, the vein would not be amenable to cannulation. These patients would continue undergoing the catheter ablation, and would remain in the study for analysis.  

One hundred and eighty five patients were randomised to the VOM ethanol infusion plus catheter ablation group, and 158 to catheter ablation only. Patients had a mean age of 66 years. Outcomes were tracked at one, three, six, nine and 12 months, with continuous, one-month monitoring taking place at the six- and 12-month stages. Valderrabano said that ablation failures could be clinical if the patients presented with symptomatic AF or AT after three months, or by monitoring if more than 30 seconds of AF or AT were detected. 

Trial procedures, for patients randomised to the VOM group prior to catheter ablation, included coronary sinus venogram to identify the VOM and angioplasty balloon cannulation with up to four injections of 1cc of ethanol from distal VOM to proximal. Left atrial voltage maps were performed before and after the injection of ethanol to quantify the alcohol-induced scar. Catheter ablation included pulmonary vein isolation in all of the patients. All patients were required to undergo a final left atrial voltage map to quantify the extent of the total tissue ablated. 

The VOM procedure was unsuccessful in 30 patients, who underwent catheter ablation, with 155 receiving both VOM ethanol infusion plus catheter ablation. Three patients died, while 10 had missing data, resulting in a final number of 142 included in the per treatment analysis. Valderrabano noted in his presentation that there was a greater presence of hypertension in the VOM group (77% vs. 66%) and a slight difference in atrial diameter between the two groups (44.8mm vs. 47mm). Longstanding persistent AF was present in 54% of VOM plus catheter ablation patients, compared to 52% of catheter ablation only patients.  

Discussing the procedural parameters, Valderrabano pointed to differences between the two patient groups, noting that the total fluoroscopy time and procedure time were longer in the VOM group, as well as noting that more patients in the VOM group underwent ablation of the mitral isthmus compared to the catheter ablation group (85% vs. 72%). Bidirectional perimetral block was achieved more commonly in the VOM plus catheter ablation group (74% vs. 51.3%), Valderrabano said. 

Ablation successdefined as freedom from AF or AT for more than 30 seconds after three monthsValderrabano said, was achieved in 38% of the patients randomised to the catheter ablation group, and 51.6% among those in the VOM plus catheter ablation group (p=0.015). AF/AT recurrence was seen in 51.9% of the catheter ablation group, compared to 40% of those undergoing VOM infusion plus catheter ablation. 

In his concluding remarks, Valderrabano said: “In persistent atrial fibrillation, vein of Marshall ethanol added to catheter ablation reduces the recurrence of atrial fibrillation and tachycardia, reduces the atrial fibrillation and may reduce the need for repeat procedures.” He noted that the limitations of the study include that VOM ethanol infusion could only be completed in 83.8% of patients, and that the procedure may increase the risk of fluid overload. 


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