EHRA 2017: Should VT Ablation Be on the Rise Without Mortality Data?

In a "strong statements and controversies" session at the European Heart Rhythm Association (EHRA) EUROPACE-CARDIOSTIM 2017 meeting, Prof Gerhard Hindricks (University of Leipzig, Germany) said something that surprised me: Ventricular tachycardia (VT) ablation is growing faster than AF ablation in percentage terms.

This comment came during a discussion after a talk titled: "VT ablation does not reduce mortality!" In his short presentation, Dr Lukas Fiedler (Brunn am Gebirge, Austria) easily supported the title of his talk. He simply showed the three major randomized controlled trials (RCTs) of VT ablation.

The US-based SMASH-VT trial showed preventive substrate-based VT ablation plus an ICD implant (vs ICD alone) reduced the incidence of device therapy in patients with old MI who presented with sustained VT.^[1] But this trial had only 64 patients in each group and did not, could not, show a reduction in mortality.
The German-based VTACH trial reported a delay of recurrence of VT with prophylactic VT ablation in patients implanted with ICDs for secondary prevention.^[2] Similarly, this trial enrolled less than 110 patients overall and did not show a reduction in mortality.
The Canadian-based VANISH trial enrolled 259 patients with sustained VT to either ablation or escalated medical therapy.^[3] Ablation reduced the incidence of a composite primary end point of death, recurrent VT, or appropriate ICD shocks, but these positive results did not lead to lower overall mortality.

How can VT ablation, an invasive risky procedure without mortality reduction, be growing at such a fast clip? At least for AF ablation, the anticipated report of the CABANA trial will soon (maybe 2018) provide us with outcomes data.

In this novel type of session, which was well-attended, young physicians gave 5-minute talks meant to provoke, and then a panel of leading experts spent 15 minutes discussing their views on the matter.

Highlights of the Panel Discussion on VT Ablation

Dr Vivek Reddy (Mount Sinai, NY) said: "I think this is right; there are no data that show VT ablation reduces mortality. And I am not sure there ever will be." He explained the difficulty in doing RCTs for VT ablation. "It's always hard randomizing patients to procedure or no procedure." Reddy said both doctors and patients often feel uncomfortable without the procedure—especially at referral centers. He described two separate industry-sponsored trials, which cost millions of dollars but were then closed due to slow enrollment.

Prof Karl-Heinz Kuck (Asklepios Klinik St Georg, Hamburg, Germany) echoed the sentiments on the challenge of doing a mortality trial. He said to show a reduction in overall mortality, it would take more than 1000 patients and many years of follow-up. "I would not survive that trial; maybe Vivek will survive the trial and he would be sitting here at age 90 to present it."

Kuck also made an interesting policy comment when asked about barriers to doing a big VT-ablation trial. He said that favorable reimbursement for procedures in Germany have led to great competition among hospitals in urban centers. For instance, Hamburg, Kuck said, had 45 hospitals to serve 2 million people. German hospitals encourage procedures, and this leads to very late VT referrals, and these patients are too sick to randomize into a trial. This fee-for-procedure model will look familiar to US physicians.

The absence of data, Kuck said, exacerbates the referral problem, because without guidance or guidelines "people will do what they want."

Prof Hindricks finished the session by introducing efforts to begin a VT management registry and to share this registry with North American doctors. "We would miss an opportunity if we don't line up for that registry," he said.

My Comments

I covered VT ablation because the increasing longevity of our patients (a good thing) means patients presenting with VT are older and sicker. Rare is the young sturdy man with a single morphology of a stable VT from an old inferior infarct.

VT ablation can be damn hard. A paper presented in a "best-graded abstract" session here at EHRA supports this contention. Dr Adrianus Wijnmaalen (Leiden, the Netherlands) presented results of an international registry of VT ablation in dilated cardiomyopathy. This data, from nine respected centers in the US, Western Europe, and Japan, included 251 patients who had ablation between 2013 and 2016. Slightly more than half the group had epicardial access. Over a mean follow-up of 10 months and multiple procedures, VT-free survival was only 55%. The rate of procedural complications was 13%, including three deaths.

Also challenging in VT ablation is the timing of the decision to go to the EP lab in the first place. The sweet spot of when to ablate can hardly be defined by algorithm.

I've seen the extremes: some patients go to the lab too early, say, after a single drug-free episode that was terminated painlessly with overdrive pacing. This seems silly; why expose a person with well-controlled arrthymia to the risks of the procedure? Other patients are treated with drugs for too long. After a relatively easy VT ablation, I've kicked myself for not doing it earlier in the course. Hindsight is sharp.

Shared decision-making rarely helps. The truth with shared decision-making surrounding VT ablation is that it turns on how confident the operator is of achieving success. A confident operator frames the choice in a positive light, an unconfident one in a negative light. Patients depend on this framing. Even when our words are neutral, patients can sense our gut feeling about the choice.

In conclusion, a mortality trial in VT ablation hardly seems necessary. Death is not always the best end point. The vast majority of patients with VT who are considered for ablation have severe or life-threatening symptoms. In this case, relief from ICD shocks, medication side effects, and a better quality of life are worthy surrogates.

What I think would help most in VT ablation is widespread buy-in that it should be done in expert centers. Selling that concept may prove far harder than any procedure.

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