First year after surgery is the optimal period to define early prosthetic valve endocarditis: a cohort study

The definition of early prosthetic valve endocarditis (PVE) remains controversial. This study aims to refine the definition of early PVE by analysing data from the Spanish endocarditis registry (Spanish Collaboration on Endocarditis).

From 2008 to 2022, 1305 consecutive cases of PVE were included. The objective was to identify the time period that best defined early PVE by comparing the frequency of cases due to nosocomial micro-organisms and the frequency of intracardiac complications. For this purpose, the periods most frequently considered in the literature were selected: the first 4, 6 or 12 months after surgery. Each of these three periods was compared with a period immediately thereafter.

Most cases of PVE diagnosed within the first year were caused by nosocomial pathogens, such as coagulase-negative staphylococci (CoNS) (236 cases, 49.3 %) and Candida spp (23 cases, 4.8 %) and was associated with higher rates of intracardiac complications (252 cases 52.6%). In patients diagnosed after the first year, these figures were 197 cases (23.8%, p<0.001); 10 cases (1.2%, p<0.001) and 298 cases (36.1%, p<0.001), respectively. No significant differences were found between the first 4 months and the 5th-6th months. When comparing cases diagnosed in the first 6 months with those diagnosed during the 7^th and 12^th months, there was a higher prevalence of cases due to CoNS (186 cases, 52.1% vs 50 cases 41%; p=0.034). Hospital mortality among patients who did not undergo surgery due to lack of indication was similar in those diagnosed during or after the first 6 months (17.1% vs 13.8%; p=0.663, respectively).

We consider that the first year after surgery is the most appropriate period for defining early PVE. Our results question whether cases diagnosed in the first 6 months after surgery constitute cases of early EVP and the need for valve replacement, as postulated by European guidelines.