Surgical treatment for infective endocarditis over three decades: a nationwide study
Authors: Dalsgaard Jensen A , Smerup M.H , Bundgaard H , Butt J.H , Bruun N.E , Torp-Pedersen C , Gislason G , Iversen K , Koeber L , Oestergaard L , Fosboel E.L 
Published: November 2020

Abstract

Background
An increasing number of patients with infective endocarditis (IE) are treated surgically over time. It is important to know how this affects patient outcome. Current studies are mainly from tertiary centres which may bias estimations of outcomes. We have therefore conducted a nationwide study of surgical outcomes during admission for IE over three decades.

Purpose
We set out to examine temporal trends in use of valve surgery for IE and these patients' characteristics and related outcomes in Denmark in the period 1998–2017.

Methods
Using Danish nationwide registries, we included patients with first-time IE (1998–2017). The study population was categorized into four groups of five-year intervals (1998–2002, 2003–2007, 2008–2012, 2012–2017). Annual number of patients with IE and the proportion who underwent valve surgery during admission were reported. Kaplan-Meier estimates and multivariable logistic regression analyses were used to compare the associated 30-day mortality risk between calendar periods. Kaplan-Meier estimates and multivariable adjusted Cox proportional hazard analyses were used compare the associated 1-year mortality risk between calendar periods.

Results
A total of 8,455 patients with first-time IE were identified in the period of 1998–2017 of which 1,906 (22.5%) underwent valve surgery (1998–2002; N=320, 2003–2007; N=468, 2008–2012; N=528, 2013–2017; N=595). The proportion of patients who underwent surgery was 21.5% in 1998 and 19.4% in 2017 (P=0.02 for trend). See figure.
For patients undergoing surgery, the median age and proportion of males increased from 58.3 years (P25-P75: 48.2–67.4) and 69.1% to 66.7 years (P25-P75: 55.2–73.0) and 73.1% in 1998–2002 and 2013–2017, respectively. Patients had an increasing burden of comorbidities including diabetes (10.3% to 14.3%), hypertension (16.9% to 37.5%) and renal disease (9.1% to 9.6%) across calendar periods. The 30-day mortality risk for patients with IE who underwent valve surgery was 10.0% (1998–2002), 10.8% (2003–2007), 6.4% (2008–2012) and 8.5% (2013–2017), respectively (P=0.09). One-year mortality risk for patients with IE who underwent valve surgery was 16.7% (1998–2002), 21.2% (2003–2007), 15.2% (2008–2012) and 16.6% (2013–2017), respectively (P=0.08). The declining 30-day and 1-year mortality was statistically significant over time when adjusting for patient characteristics (P=0.01 and P≤0.0001, respectively).

Conclusion
From a nationwide, unselected cohort of patients with first-time IE, around 1/5 undergo surgery during admission. Surgical IE-cases are older and sicker now compared to 10–20 years ago. In spite of this, there was a trend towards a decreased associated 30-day and 1-year mortality over time. Our data show a lower rate of surgery in IE than in most prior studies and we believe that this is due to the nationwide, unselected nature of our study.
Infective endocarditis and surgery

Funding Acknowledgement
Type of funding source: None