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Benito-González et al. Mini-invasive Surg 2020;4:67 I http://dx.doi.org/10.20517/2574-1225.2020.54 Page 3 of 9

30 days was defined as the implantation of at least 1 clip with residual MR ≤ 2+ and transmitral
valvular mean gradient < 5 mmHg, in the absence of major adverse events (death, stroke, unscheduled
cardiovascular intervention, or device detachment). Device-related complications such as fracture,
migration, embolization or partial detachment were considered as structural device failure. Functional
failure was defined as the suboptimal result of PMVR during follow up (residual or recurrent MR 3+ or
4+ and/or transmitral mean gradient ≥ 5 mmHg). Anemia was defined according to the World Health
[9]
Organization as a concentration of serum hemoglobin < 12 g/dL in women and < 13 g/dL in men . A
composite primary endpoint of readmission for HF and all-cause death was established to define the
prognostic impact of frailty in this series.

Statistical analysis
Continuous variables were summarized as mean ± standard deviation or as medians and interquartile
range, and were compared using unpaired Student t-tests or the non-parametric Wilcoxon rank sum tests
if the normal distribution of the variables could not be demonstrated. Derangement from the normal
distribution was assessed with the Shapiro-Wilk test. Categorical variables were described as percentages
and compared using Chi-square or Fisher exact tests accordingly to expected frequency over or below
5, respectively. Survival curves for time-to-event were constructed on the basis of all available follow-up
data using Kaplan-Meier estimates, and comparisons between frail and non-frail PMVR patients were
performed using the log-rank test. Cox regression multivariate analysis was performed to evaluate the
prognostic impact of frailty as an independent predictor for HF hospitalizations and all-cause mortality.
Variables found to be statistically significant in the univariate analysis as well as others with clinical interest
were included as covariates in the multivariable model. A P-value < 0.05 was regarded as statistically
significant. Statistical analyses were performed using STATA software version 14.2.

RESULTS
In the study period, 70 patients (age 75.3 ± 9.9 years, 65.7% male) underwent elective PMVR in our center.

Study population
Baseline characteristics of patients included in the study cohort are summarized in Table 1, grouped by
the presence of frailty criteria. Almost all patients (94.3%) had been admitted previously for HF, or were
in advanced NYHA functional class III or IV. The etiology of the MR was predominantly functional, and
patients were considered to be at high risk for conventional surgery according to surgical risk scales or
Heart Team consensus. The prevalence of comorbidities was similar to other contemporary cohorts.

FRAIL questionnaire scores showed the following distribution in the cohort: score 0, 5.71%; score 1, 22.9%;
score 2, 32.9%; score 3, 28.6%; score 4, 10.0%; score 5, 0%. Overall, 27 patients (38.6%) had a FRAIL score
greater than 2, meeting frailty criteria. Patients classified as frail were older (P = 0.043), and had lower body
mass index (0.030), higher prevalence of low serum albumin < 4 g/dL (P = 0.046), and anemia (0.046),
higher number of admissions for HF in the previous year (P = 0.044), and worse prognosis estimated by
Seattle HF risk score (P = 0.005). Likewise, they presented worse pre-procedural NYHA functional class (P
= 0.104), higher levels of NT-proBNP (P = 0.070), and higher surgical risk (P = 0.060), as well as a higher
prevalence of comorbidities (hypertension, advanced kidney disease, chronic obstructive pulmonary
disease, or cognitive impairment), although this did not reach statistical significance.

Procedural results
At least one clip was successfully implanted in all patients, and 28 cases (40%) were treated with 2 or
more clips. No significant differences were found in the duration of the procedure (P = 0.749), the time of
fluoroscopy (P = 0.768), or the number of clips implanted between frail and non-frail patients (P = 0.359,
Table 2). One patient (1.4%) underwent emergency valve replacement due to rupture of the subvalvular