CRT Landscape Shifts After New HF Guidelines in European Survey, Often for Better

May 20, 2017

PARIS, FRANCE — Clinicians in Western Europe continue to implant cardiac resynchronization therapy (CRT) devices in lots of patients with heart failure for whom the clinical-trial evidence base for benefit is weak or nonexistent, such as those older than 75, with atrial fibrillation, or with a narrow QRS interval[1], suggests a recent survey of CRT practice patterns.

Still, compared with previous practice in the region, there was a significant drop in CRT use in patients with a QRS <130 ms on their baseline ECG, for whom the guidelines contraindicate CRT, and improved use of some adjuvant heart-failure meds.

The findings come from a subanalysis of a 42-country, 15-month survey[2] of patients implanted with CRT devices, sponsored and designed by the Heart Failure Association (HFA) and European Heart Rhythm Association (EHRA), that documents the CRT experience of >11,000 patients from 296 centers.

Dr Camilla Normand

In their presentation here at the European Society of Cardiology (ESC) Heart Failure 2017, Dr Camilla Normand (Stavanger University Hospital, Norway) focused on a subset of 5313 patients in 13 countries that had made up the entirety of a previous similar survey reported in 2009, allowing her to directly compare the two experiences separated by at least 8 years. That CRT Survey I had included a total of 2438 CRT recipients.

The countries in both analyses were Austria, Belgium, France, Germany, Ireland, Israel, Italy, Netherlands, Norway, Spain, Sweden, Switzerland, and the UK.

Many changes in CRT use in the new CRT Survey II reflect the updated 2016 European heart-failure guidelines, Normand observed. Of note, she said, one in five CRT recipients now get the pacing therapy for a newly defined class IA indication in NYHA class 3–4 as an alternative to conventional pacing when it involves a high degree of atrioventricular (AV) block.

From Snapshot to Performance Measures

The preponderance of older patients and those with AF or narrow QRS duration and other guideline deviations in the second survey are "concerns," but there are also positive signs, like a high degree of accompanying optimal medical therapy, including increased use of aldosterone antagonists, according to discussant Prof Faiez Zannad (Institut National de la Santé et de la Recherche Médicale, Vandoeuvre-lès-Nancy, France).

He said he encourages designers of the survey, which illustrates how CRT is used in practice, "to move forward from taking a snapshot to implementing performance measures and changing practice." Zannad said across the Atlantic "they've done a good job with the Get with the Guidelines initiative. We still have to see something similar happen here in Europe."

Demographic, Clinical, and Baseline ECG Features in CRT Survey I vs CRT Survey II

Parameter CRT Survey I, n=2438 (%) CRT Survey II subset, n=5313 (%)
Age >75 years 31 39*
Female 27 25
Ischemic etiology 51 42*
NYHA class 2 20 40*
Atrial fibrillation 23 26
LBBB 68 73*
QRS <130 ms 19 15*
QRS <120 ms 9 9
*P<0.01

Importantly, much of the difference in results of the two surveys can be attributed to major trials that had yet to influence practice in 2009, including MADIT-CRT and RAFT, and to last year's revamp of European HF guidelines that presented finely tuned CRT recommendations aimed at more selective treatment of patients mostly likely to benefit.

Speaking with heartwire from Medscape, Normand observed that the presence of a left bundle branch block (LBBB) QRS morphology in the 2016 HF guidelines is associated with a stronger CRT recommendation, although lately there's disagreement about the importance of QRS morphology in identifying likely CRT responders. Still, the prevalence of recipients with LBBB rose slightly but significantly across the surveys to almost three-fourths of the cohort.

More solid is the latest guideline class 1, level B recommendation for CRT in patients with QRS 130–149 ms, and class 1, level A recommendation for QRS >150 ms, both in the presence of LBBB; CRT remains recommended at those QRS durations without LBBB, although to a lesser degree.

Accordingly, the proportion with QRS duration <130 ms fell significantly from 19% to 15%; the guidelines give QRS in that range a "thumbs down," with a class III, level A recommendation. The prevalence of QRS <120 ms held steady at 9%.

Demographics

CRT Survey II saw the proportion of CRT recipients who were older than 75 rise significantly, to almost 40%, from less than one-third in CRT Survey I. Norman said when interviewed that in such older patients and in those with AF, "it's not that we know CRT doesn't work, it's just that we don't have the evidence. If you are over 75, you don't get included in the trials."

Although there's plenty of evidence that CRT improves outcomes in both sexes, "We're still doing very badly when it comes to gender. Still, a majority of patients implanted are males," Normand said; women accounted for only one-fourth of patients in the 13-country analysis.

The proportion of patients getting CRT while in NYHA class 2 doubled from one-fifth to 40% of cases, which is consistent with the expanded guidelines. "But we're also seeing a few in class 1, which is not a guideline indication," she said.

Optimal Medical Therapy

In her presentation, Normand pointed to changes in the proportion of patients discharged on different heart-failure meds, including significant declines in those put on diuretics, ACE inhibitors, or angiotensin-receptor blockers (ARB), antiarrhythmics, and antiplatelet agents. Those decreases, she said, appear consistent with the newer guidelines that extend CRT to patients who are less symptomatic. Use of beta-blockers held steady between the two surveys.

The significant jump in patients put on aldosterone inhibitors, she said, may be related to results of the EMPHASIS-HF trial, released in 2010, in which use of eplerenone (Inspra, Pfizer) significantly benefited patients with even mild systolic heart failure.

Normand said a broader analysis of the treatment's contemporary use in the full roster of countries in CRT Survey II points to some noteworthy regional variation in the treatment's application. The findings are expected to be presented at next month's European Heart Rhythm Association (EHRA) meeting.

Prevalence of Discharge Medications, CRT Survey I vs CRT Survey II

Discharge medications CRT Survey I, n=2438 (%) CRT Survey II subset, n=5313 (%)
Diuretics 88 76*
Beta-blockers 84 86
ACE inhibitors or ARBs 91 84*
Aldosterone antagonists 46 55*
Antiarrhythmics 24 18*
Anticoagulants 45 46
Antiplatelets 50 42*
*P<0.01

Normand said she has no relevant financial relationships. Zannad discloses receiving fees for serving on a s teering committee or data and safety monitoring board for Bayer, Boston Scientific, GE Healthcare, Janssen, Novartis, Pfizer, Resmed, and Takeda; and receiving consultant or scientific advisory board fees from Actelion, AstraZeneca, Amgen, Boehringer, CEVA, CVRx, EDDH, Eli Lilly, Merck, Quantum, Genomics, Relypsa, Vifor, and ZS Pharma.

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