Contemporary guidelines highly recommend patients with heart failure with reduced ejection fraction (HFrEF) be on all four drug classes that together have shown clinical clout, including improved survival, in major randomized trials.
Although many such patients don’t receive all four drug classes, the more that are prescribed to those with primary-prevention implantable defibrillators (ICD), the better their odds of survival, a new analysis suggests.
The cohort study of almost 5,000 patients with HFrEF and such devices saw their all-cause mortality risk improve stepwise with each additional prescription they were given toward the full quadruple drug combo at the core of modern HFrEF guideline-directed medical therapy (GDMT). The four classes are sodium-glucose cotransporter 2 inhibitors, beta-blockers, mineralocorticoid receptor antagonists (MRA), and renin-angiotensin system (RAS) inhibitors.
That inverse relation between risk and number of GDMT medications held whether patients had solo-ICD or defibrillating cardiac resynchronization therapy (CRT-D) implants, and were independent of device-implantation year and comorbidities, regardless of HFrEF etiology.
“If anybody had doubts about really pushing forward as much of these guideline-directed medical therapies as the patient tolerates, these data confirm that, by doing so, we definitely do better than with two medications or one medication,” Samir Saba, MD, University of Pittsburgh Medical Center, said in an interview.
The analysis begs an old and challenging question: Do primary-prevention ICDs confer clinically important survival gains over those provided by increasingly life-preserving recommended HFrEF medical therapy?
Given the study’s incremental survival bumps with each added GDMT med, “one ought to consider whether ICD therapy can still have an impact on overall survival in this population,” proposes a report published online in JACC Clinical Electrophysiology, with Dr. Saba as senior author.
In the adjusted analysis, the 2-year risk for death from any cause in HFrEF patients with primary-prevention devices fell 36% in those with ICDs and 30% in those with CRT-D devices for each added prescribed GDMT drug, from none up to either three or four such agents (P < .001 in both cases).
Only so much can be made of nonrandomized study results, Saba observed in an interview. But they are enough to justify asking whether primary-prevention ICDs are “still valuable” in HFrEF given current GDMT. One interpretation of the study, the published report noted, is that contemporary GDMT improves HFrEF survival so much that it eclipses any such benefit from a primary-prevention ICD.
Both defibrillators and the four core drug therapies boost survival in such cases, “so the fundamental question is, are they additive. Do we save more lives by having a defibrillator on top of the medications, or is it overlapping?” Dr. Saba asked. “We don’t know the answer.”
For now, at least, the findings could reassure clinicians as they consider whether to recommended a primary-prevention ICD when there might be reasons not to, as long there is full GDMT on board, “especially what we today define as quadruple guideline-directed medical therapy.”
Recently announced North American guidelines defining an HFrEF quadruple regimen prefer – beyond a beta-blocker, MRA, and SGLT2 inhibitor – that the selected RAS inhibitor be sacubitril/valsartan (Entresto, Novartis), with ACE inhibitors or angiotensin-receptor blockers (ARBs) as a substitute, if needed.
Nearly identical European guidelines on HFrEF quad therapy, unveiled in 2021, include but do not necessarily prefer sacubitril/valsartan over ACE inhibitors as the RAS inhibitor of choice.