Secondary end-point results
Table 2 shows the echocardiographic parameters at baseline, 6 months and
the changes during the 6 months of follow-up. Mean reduction in LVESV
(reverse remodeling) was 25.3% and mean increase in LVEF was 9.4
absolute points. The subjects with device programmed using anatomical
approach had a non-significant higher reverse remodeling than those
using the electrical approach (32.2%±25.2% vs. 19.4%±36.2%, p= 0.12)
and a significant higher increase in LVEF (14.2%±11.9% vs 8%±12.6%,
p=0.04). Finally, non-ischemic patients had a significant higher reverse
remodeling in comparison to ischemic patients (32.6±34.1% vs
10.5±28.4%, p=0.04) and a significant higher increase in LVEF
(12.5%±12.1% vs 6.4%±12.8%, p=0.04).
The percentage of super-responder (mean absolute LVEF increase of
>14% at 6 months post-implant compared to no pacing at
baseline) was 35.1%. It was observed a non-significant increase in
percentage of super-responders in patients with device programmed using
anatomical vs electric approach (48.0% vs 27.8%, p=0.08) and in
non-ischemic vs ischemic patients (39.1% vs 27.3%, p=0.26)
The New York Heart Association (NYHA) class changes at 6 months are
shown in Table 3. Before implant 35% of patients were on class III,
whereas at 6 months only 12% of patients were on class III and most
remained in class I or II. At 6 months, 8% and 14% of patients
programmed using the anatomical and electrical approach, respectively,
remained in class III.
We also evaluated the percentage of responders using the clinical
composite score. A subject was defined as non-responder if suffered any
of the following: death, heart failure hospitalization or worsening of
the NYHA class. At 6 months of follow-up only 5% of patients were
considered as clinical non-responders.
All 105 patients that consented to participate in the study were
included for the evaluation of clinical outcomes. Mortality was 1.9%
and 11.4% of patients were admitted to the hospital for any reason.
Finally, we compared the QUARTO III with QUARTO II clinical outcomes to
evaluate potential benefits of MPP over conventional biventricular
pacing. There were significant differences in baseline characteristics
between both cohorts (Table 4). Statistically significant differences
were evident for baseline age, NYHA class, LVEF and prevalence of
hypertension and diabetes mellitus. The response rate in Quarto II was
61.8%, that was similar to the response rate found in Quarto III
(p=0.684). Incidence of the combined endpoint of mortality and or
all-cause hospitalizations was lower in Quarto III in comparison to
QUARTO II (12.4% vs 25.4%, p=0.004, figure 2). A multivariate analysis
was performed using a Cox’s proportional hazard regression model to
evaluate the benefits in clinical outcomes observed in the MPP cohort
adjusting the demographic and baseline covariates. Patients included in
QUARTO II had a significant higher risk of mortality and or all cause
hospitalizations (HR: 1.99 (95% CI, 1.69-2.29), p=0.03).