Women in the randomized MADIT-CRT trial had
significantly greater reductions in death or HF, HF alone and all-cause
mortality with cardiac resynchronization therapy using defibrillator than men.
Researchers of the Multicenter Automatic Defibrillator
Implantation Trial with Cardiac Resynchronization Therapy (MADIT-CRT) enrolled
1,820 patients (24.9% women) and analyzed sex-specific outcomes comparing the
effect of cardiac resynchronization therapy with defibrillator (CRT-D) against
implantable cardioverter defibrillator therapy.
They found better results with
CRT-D for female patients, culminating with a 70% reduction
in HF (P<.001) and a 69% reduction in death or HF (P<.001),
which were significantly lower when compared with men (P<.01 for
Also reported was a 72% reduction of all-cause mortality
in women (P<.02), as well as an 82% reduction in mortality for those
with QRS of at least 150 ms and 78% reduction in those with left bundle branch
block (LBBB) conduction disturbance. However, for female patients with
non-LBBB, rates of death or HF (HR=1.97; 95% CI, 0.40-9.64), as well as HF
alone (HR=1.95; 95% CI, 0.40-9.53), were nearly two times greater.
Significant differences in baseline characteristics
between women and men, the researchers wrote, could explain part of the
observed findings because a greater proportion of women had a substrate of
nonischemic cardiomyopathy and an underlying LBBB pattern.
“It is possible that among patients with heart
disease, the risk of HF is greater for women than for men, resulting in a
greater benefit from preventive CRT-D therapy in women,” they said.
Cardiology Today’s initial coverage of
MADIT-CRT can be viewed
here. – by Brian Ellis
Dr. Arshad and her colleagues report that women in the MADIT-CRT trial
obtained significantly greater reductions in death or HF, HF alone, and
all-cause mortality with CRT-D therapy than men. Although these findings were
associated with greater echocardiographic evidence of reverse remodeling in
women compared with men, the differences were small. Furthermore, female
patients were more likely to have nonischemic cardiomyopathy and LBBB and less
likely to have renal dysfunction than men; these factors are known to be
associated with improved outcomes. Conversely, men had more ischemic heart
disease, prior revascularization and renal dysfunction. Thus, the overall
findings are not surprising.
On the other hand, it is notable that women with ICDs rather than CRT-Ds
had worse outcomes than men, and women had a significantly overall higher
likelihood of device-related adverse events than men. Despite these findings,
just as in the case of atrial fibrillation and age, male gender should not be
taken to mean that men should not receive CRT-D therapy, since the subset is
less likely to respond. Patients who are male, the elderly and those with
atrial fibrillation simply have blunting of beneficial responses, not absent
response. Why women with nonischemic cardiomyopathy seem to be more responsive
to CRT than are men remains unknown.
– Andrew E. Epstein, MD
Cardiology Today Editorial Board
Disclosure: Dr. Epstein reports having served on the Data and Safety Monitoring Board for Boston Scientific, and has received speaking honoraria, fellowship support and research grants from Boston Scientific. He has also served on Data and Safety Monitoring Boards for and has received research grants, speaking honoraria and fellowship support from Medtronic/Cryocath and St. Jude Medical. Dr. Epstein also reports having received research grants and speaking honoraria from Biotronik, and has received research grants from Cameron Health and Spectranetics.