Midterm results of mitral valve repair with lifting annuloplasty strip for acute phase infective endocarditis

Contemporary trends and outcomes of mitral valve surgery for infective endocarditis

BACKGROUND

Contemporary data on mitral valve (MV) surgery in patients with infective endocarditis (IE) are limited.

METHODS

The National Inpatient Sample was queried to identify patients with IE who underwent MV surgery between 2003 and 2016. We assessed (a) temporal trends in the incidence of MV surgery for IE, (b) morbidity, mortality, and cost of MV repair vs replacement, and (c) predictors of in-hospital mortality.

RESULTS

The proportion of MV operations involving patients with IE increased from 5.4% in 2003 to 7.3%, and the proportion of MV repair among those undergoing surgery for IE increased from 15.2% to 25.0% (P_trend  < .001). In-hospital mortality was higher in the replacement group (11.3% vs 8.1%; P < .001), and this excess mortality persisted after propensity score matching (11.2% vs 8.1%; P < .001), and in sensitivity analyses excluding concomitant surgery (unadjusted 11.3% vs 4.8%; adjusted 8.5% vs 4.5%; P < .001), and stratifying patients by the time of operation (within 7 days, 11.3% vs 6.8%; P < .001 and >7 days, 11.9% vs 9.1%; P = .012). In the propensity-matched cohorts, shock and need for tracheostomy were more frequent in the replacement group, but rates of stroke, pacemaker implantation, new dialysis, and blood transfusion were similar. Mitral valve repair was, however, associated with shorter hospitalizations, more home discharges, and less cost. In a multivariate regression analysis, age above 70 and chronic dialysis were the strongest predictors of in-hospital mortality.

CONCLUSION

Mitral valve repair in IE patients is associated with lower in-hospital mortality, resource utilization, and cost compared with MV replacement.

Evaluation of Infection Resistance of Biodegradable versus Conventional Annuloplasty Rings in an in vivo Rat Subcutaneous Model

Background: Biodegradable atrioventricular annuloplasty rings are theoretically more infection resistant due to their intra-annular implantation technique and nonporous structures (monofilament of poly-1,4-dioxanone). The aim of this study was to investigate the infection resistance of a biodegradable annuloplasty ring (Kalangos-Bioring®) in a rat subcutaneous implantation model and to compare it with a commonly used conventional annuloplasty ring (Edwards Physio II®). Methods: This study included 32 Wistar albino rats which were divided into 2 groups according to the implantation of sterile or infected annuloplasty rings as control and study groups. Each animal had 2 implantation pockets (made on the right and left side of the dorsal median line) where 1 cm of the biodegradable annuloplasty ring was implanted into one pocket and 1 cm of the conventional annuloplasty ring was implanted into the other pocket. The infection model was created by topical inoculation of 1 mL Staphylococcus aureus strain (2 × 107 colony-forming units/mL) into the implantation pockets before skin closure. Each group was equally divided into 4 subgroups according to different follow-up schedules. The animals were inspected for local as well as systemic infection signs, and the rings were explanted at weeks 2, 4, 9, and 14 following implantation. Implantation pockets were evaluated macroscopically as well as by histopathological examinations. Microbiological analysis of the explanted implants with surrounding tissue was done by using quantitative sonication method. Results: Conventional ring-implanted pockets showed a more prominent inflammation reaction than the biodegradable ring-implanted pockets, and this characteristic was found to be accentuated with bacterial contamination. The sterile rings did not reveal any positive cultures in either group. The number of positive cultures found in conventional rings contaminated with S. aureus was greater than in the biodegradable ring group (11/16 vs. 2/16 positive cultures, respectively; p = 0.0032). The amounts of growing bacteria in the culture environment were also statistically significantly higher in the conventional ring group (7,175 ± 5,936 vs. 181 ± 130 colony-forming units/mL, respectively; p < 0.0005). Conclusions: This is the first experimental study confirming the theoretical advantage of the infection resistance of the biodegradable annuloplasty ring (Kalangos-Bioring®) when implanted in an active infectious environment. Large animal models mimicking clinical scenarios and clinical comparative studies are needed to verify our results.

HACEK endocarditis: a review

INTRODUCTION

The HACEK group, referring to Haemophilus spp., Aggregatibacter actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae, is a rare cause of infective endocarditis (IE). It causes the majority of Gram-negative endocarditis cases and has an excellent prognosis and simple management if properly identified. However, delay in diagnosis and associated complications can render the infection fatal.

AREAS COVERED

Over the past few decades, there have been tremendous advancements in understanding the manifestations and progression of HACEK endocarditis (HE). This review tackles the epidemiology of HE, the microbiological characteristics of each organism in the HACEK group, the methods used to diagnose HE, the clinical manifestations, complications, and mortality of patients with HE, as well as the recommended treatment and preventive methods. Expert Commentary: The lack of robust randomized controlled trials in diagnosis and treatment of HE makes it difficult to determine the optimal management of such infections. Nevertheless, advancements in culturing methods have shown progress in isolating and identifying these fastidious organisms. Positive blood cultures for any of the HACEK organisms in the setting of no definite focus of infection is highly suggestive of HE. In such cases, treatment with ceftriaxone or a fluoroquinolone, even without obtaining antibiotic susceptibilities, should be initiated. Moreover, the decision to proceed with surgical intervention should be individualized. As is the case for other IE, HE requires the collaboration of a multidisciplinary team consisting of the infectious disease specialist, cardiologist, cardiothoracic surgeon, and the microbiologist.