Follow-up: mortality outcomes, long-term predictors
The median follow-up time was 54 months (4.5 years). We found that 182 out of the 435 total enrolled patients died, with a global mortality rate of 41%. In particular, early mortality (first 30 post-operative days) rate accounted for 32 patients (7%) and long-term mortality rate for 150 patients (34%) of the total population. With regard to early mortality causes, the most frequent was sepsis (accounting for 16 patients, 50% of deaths), followed by cardiovascular non-arrhythmic causes (10 patients, 31% of deaths, including ischemia, pulmonary embolism and heart failure), intra-procedural complications (2 patient 6%), non-cardiovascular events (3 patients 9%) and arrhythmic cause (1 patient, 3%). The most frequent cause of long-term mortality was represented by multiple chronic diseases (94 patients out of 150 deaths, 62%); secondly, non-arrhythmic cardiovascular causes accounted for 36 patients (24% of deaths), sepsis for 6 patients (4%) (Figure 1).
At univariate analysis, as showed in Table II, long-term mortality predictors were: chronic kidney disease defined as severe reduction of eGFR (<30ml/min/1.73m2), elderly, referral from spoke centres, diabetes, left ventricular (LV) systolic dysfunction defined as LVEF ≤40%, infective indication to TLE, sepsis at admission, number of extracted leads, intravenous antibiotic therapy and diuretics. At multivariate analysis, long-term mortality independent predictors were represented by advanced age, severe chronic kidney disease and reduced LVEF (Table III, Figure 2).
Kaplan-Meier curves summarized the different survival on the basis of three independent predictors of long-term mortality (Figures 3a-c). At 54 months of follow-up, elderly patients with severe chronic kidney disease and patients with LV systolic dysfunction had a higher mortality rate compared to younger, patients with normal or mild chronic kidney disease and patients with LVEF >40% (Figure 3a-c). Particularly, Kaplan–Meier analysis demonstrated a cumulative mortality rate of 83% in patients with age ≥77 years, 68% in patients with severe chronic kidney disease, and 73% in those with LV systolic dysfunction at 90 days from discharge.