|
Home
FOCUS ON CARDIOVASCULAR DISORDERS
Omar Badawi, Section Advisor
Cardiac resynchronization therapy for patients with asymptomatic
mild heart failure
Key point: Results from a large trial involving more
than 1,800 patients with New York Heart Association (NYHA) Class I or II
heart failure showed that patients randomized to cardiac
resynchronization therapy (CRT) defibrillators had a 34% relative
reduction in the risk of all-cause mortality or first heart failure
event compared with patients who received a standard implantable
cardioverter defibrillator (ICD).
Finer points: The results of MADIT-CRT (Multicenter
Automatic Defibrillator Implantation Trial with Cardiac
Resynchronization Therapy) were simultaneously presented at the 2009
European Society of Cardiology Congress in Barcelona and published in
the New England Journal of Medicine. Patients with ischemic or
nonischemic NYHA Class I or II heart failure with an ejection fraction
of 30% or less and a wide QRS complex (130 ms or more) were randomized
in a 3:2 ratio to CRT with an ICD (CRT–ICD, n = 1,089) or a
standard ICD (n = 731). Death from any cause or nonfatal heart failure
events was assessed as the primary endpoint.
Baseline demographic characteristics were similar between the two
groups; patients had a mean age of 64.5 years, 75% were male, 90% were
white, and approximately 55% of patients in both groups had ischemic
heart disease. After a mean duration of 2.4 years, the primary endpoint
occurred in 17.2% of patients in the CRT–ICD group compared with
25.3% of patients in the standard ICD group (hazard ratio [HR] 0.66 [95%
CI 0.52–.84], P = 0.001). This significant difference was
driven by a reduction in heart failure events in the CRT–ICD group
(13.9% vs. 22.8%, HR 0.59 [0.41–0.74], P < 0.001) that
was primarily noted in patients with a QRS duration of 150 ms or more.
Death from any cause occurred at a similar rate in the two groups (6.8%
for CRT–ICD vs. 7.3% for standard ICD), and similar results were
observed for patients with ischemic and nonischemic heart failure. The
investigators also reported that left ventricular volume was reduced,
and that the ejection fraction was increased to a significantly greater
degree, in patients in the CRT–ICD group. Serious adverse events
occurred with similar frequency in the two groups.
What you need to know: In 2008, the American College
of Cardiology/American Heart Association in collaboration with the
American Association for Thoracic Surgery and Society of Thoracic
Surgeons published guidelines on the use of implantable devices. These
guidelines recommend that CRT–ICDs be used in patients with NYHA
Class III or IV heart failure who have an ejection fraction of 35% or
less and a QRS duration of 120 ms or more. The results of the current
trial may be used to support the expanded use of CRT–ICDs for
certain patients with NYHA Class I or II heart failure. In an
accompanying editorial, Mariell Jessup, MD, pointed out that based on
the results of MADIT-CRT, 12 patients would need to be treated to
prevent a single heart failure event without a mortality benefit. Jessup
recommended that any expanded indication for a CRT–ICD in patients
with NYHA Class I or II heart failure be limited to patients with
“a QRS duration of more than 150 ms in whom marked symptoms have
been controlled with optimal medical therapy,” given the cost of
this intervention and lack of mortality benefit.
What your patients need to know: Educate patients
with asymptomatic to mild heart failure that a new study shows that
CRT–ICD reduces heart failure events and appears to slow the
progression of the disease but showed no effect on mortality. Patients
interested in CRT–ICDs should consult their cardiologists to
determine if they are candidates.
Sources:
Related resource on www.pharmacist.com:
|
