NatIonal Danish endocarditis stUdieS - Design and objectives of the NIDUS registry.

AIMS: The NatIonal Danish endocarditis stUdieS (NIDUS) registry aims to investigate the mechanisms contributing to the increasing incidence of infective endocarditis (IE) and to discover risk factors associated to the course, treatment and clinical outcomes of the disease. METHODS: The NIDUS registry was created to investigate a nationwide unselected group of patients hospitalized for IE. The National Danish healthcare registries have been queried for validated IE diagnosis codes (International Classification of Disease, 10th edition [ICD-10]: DI33, DI38, and DI398). Subsequently, a team of 28 healthcare professionals, including experts in endocarditis, will systematically review and evaluate all identified patient records using the modified Duke Criteria and the 2015 European Society of Cardiology modified diagnostic criteria. The registry will contain all cases with definite or possible IE found in primary data sources in Denmark between January 1, 2016, and December 31, 2021. We will gather individual patient data, such as clinical, microbiological, and echocardiographic characteristics, treatment regimens, and clinical outcomes. A digital data collection form will be used to the gathering of data. A sample of approximately 4,300 individual patients will be evaluated using primary data sources. CONCLUSIONS AND PERSPECTIVES: The NIDUS registry will be the first comprehensive nationwide IE registry, contributing critical knowledge about the course, treatment, and clinical outcomes of the disease. Additionally, it will significantly aid in identifying areas in which future research is needed.

Attainment of Target Antibiotic Levels by Oral Treatment of Left-Sided Infective Endocarditis: A POET Substudy.

BACKGROUND: In the POET (Partial Oral Endocarditis Treatment) trial, oral step-down therapy was noninferior to full-length intravenous antibiotic administration. The aim of the present study was to perform pharmacokinetic/pharmacodynamic analyses for oral treatments of infective endocarditis to assess the probabilities of target attainment (PTAs). METHODS: Plasma concentrations of oral antibiotics were measured at day 1 and 5. Minimal inhibitory concentrations (MICs) were determined for the bacteria causing infective endocarditis (streptococci, staphylococci, or enterococci). Pharmacokinetic/pharmacodynamic targets were predefined according to literature using time above MIC or the ratio of area under the curve to MIC. Population pharmacokinetic modeling and pharmacokinetic/pharmacodynamic analyses were done for amoxicillin, dicloxacillin, linezolid, moxifloxacin, and rifampicin, and PTAs were calculated. RESULTS: A total of 236 patients participated in this POET substudy. For amoxicillin and linezolid, the PTAs were 88%-100%. For moxifloxacin and rifampicin, the PTAs were 71%-100%. Using a clinical breakpoint for staphylococci, the PTAs for dicloxacillin were 9%-17%.Seventy-four patients at day 1 and 65 patients at day 5 had available pharmacokinetic and MIC data for 2 oral antibiotics. Of those, 13 patients at day 1 and 14 patients at day 5 did only reach the target for 1 antibiotic. One patient did not reach target for any of the 2 antibiotics. CONCLUSIONS: For the individual orally administered antibiotic, the majority reached the target level. Patients with sub-target levels were compensated by the administration of 2 different antibiotics. The findings support the efficacy of oral step-down antibiotic treatment in patients with infective endocarditis.

Rifampicin reduces plasma concentration of linezolid in patients with infective endocarditis.

BACKGROUND: Linezolid in combination with rifampicin has been used in treatment of infective endocarditis especially for patients infected with staphylococci. OBJECTIVES: Because rifampicin has been reported to reduce the plasma concentration of linezolid, the present study aimed to characterize the population pharmacokinetics of linezolid for the purpose of quantifying an effect of rifampicin cotreatment. In addition, the possibility of compensation by dosage adjustments was evaluated. PATIENTS AND METHODS: Pharmacokinetic measurements were performed in 62 patients treated with linezolid for left-sided infective endocarditis in the Partial Oral Endocarditis Treatment (POET) trial. Fifteen patients were cotreated with rifampicin. A total of 437 linezolid plasma concentrations were obtained. The pharmacokinetic data were adequately described by a one-compartment model with first-order absorption and first-order elimination. RESULTS: We demonstrated a substantial increase of linezolid clearance by 150% (95% CI: 78%-251%), when combined with rifampicin. The final model was evaluated by goodness-of-fit plots showing an acceptable fit, and a visual predictive check validated the model. Model-based dosing simulations showed that rifampicin cotreatment decreased the PTA of linezolid from 94.3% to 34.9% and from 52.7% to 3.5% for MICs of 2 mg/L and 4 mg/L, respectively. CONCLUSIONS: A substantial interaction between linezolid and rifampicin was detected in patients with infective endocarditis, and the interaction was stronger than previously reported. Model-based simulations showed that increasing the linezolid dose might compensate without increasing the risk of adverse effects to the same degree.

Surgical treatment of patients with infective endocarditis: changes in temporal use, patient characteristics, and mortality-a nationwide study.

BACKGROUND: Valve surgery guidelines for infective endocarditis (IE) are unchanged over decades and nationwide data about the use of valve surgery do not exist. METHODS: We included patients with first-time IE (1999-2018) using Danish nationwide registries. Proportions of valve surgery were reported for calendar periods (1999-2003, 2004-2008, 2009-2013, 2014-2018). Comparing calendar periods in multivariable analyses, we computed likelihoods of valve surgery with logistic regression and rates of 30 day postoperative mortality with Cox regression. RESULTS: We included 8804 patients with first-time IE; 1981 (22.5%) underwent surgery during admission, decreasing by calendar periods (N = 360 [24.4%], N = 483 [24.0%], N = 553 [23.5%], N = 585 [19.7%], P = < 0.001 for trend). For patients undergoing valve surgery, median age increased from 59.7 to 66.9 years (P ≤ 0.001) and the proportion of males increased from 67.8% to 72.6% (P = 0.008) from 1999-2003 to 2014-2018. Compared with 1999-2003, associated likelihoods of valve surgery were: Odds ratio (OR) = 1.14 (95% CI: 0.96-1.35), OR = 1.20 (95% CI: 1.02-1.42), and OR = 1.10 (95% CI: 0.93-1.29) in 2004-2008, 2009-2013, and 2014-2018, respectively. 30 day postoperative mortalities were: 12.7%, 12.8%, 6.9%, and 9.7% by calendar periods. Compared with 1999-2003, associated mortality rates were: Hazard ratio (HR) = 0.96 (95% CI: 0.65-1.41), HR = 0.43 (95% CI: 0.28-0.67), and HR = 0.55 (95% CI 0.37-0.83) in 2004-2008, 2009-2013, and 2014-2018, respectively. CONCLUSIONS: On a nationwide scale, 22.5% of patients with IE underwent valve surgery. Patient characteristics changed considerably and use of valve surgery decreased over time. The adjusted likelihood of valve surgery was similar between calendar periods with a trend towards an increase while rates of 30 day postoperative mortality decreased.

Self-assessed health status and associated mortality in endocarditis: secondary findings from the POET trial.

PURPOSE: Self-assessed poor health status is associated with increased risk of mortality in several cardiovascular conditions, but has not been investigated in patients with endocarditis. We examined health status and mortality in patients with endocarditis. METHODS: This is a re-specified substudy of the randomized POET endocarditis trial, which included 400 patients. Patients completed the single-question self-assessed health status from the Short-Form 36 questionnaire at time of randomization and were categorized as having poor or non-poor (excellent/very good, good, or fair) health status. Self-assessed health status and all-cause mortality were examined by a Cox regression model. RESULTS: Self-assessed health status was completed by 266 (67%) patients with a mean age of 68.0 years (± 11.8), 54 (20%) were females, and 86 (32%) had one or more major concurrent medical conditions besides endocarditis. The self-assessed health status distribution was poor (n = 21, 8%) and non-poor (n = 245, 92%). The median follow-up was 3.3 years and death occurred in 9 (43%) and 48 (20%) patients reporting poor and non-poor health status, respectively, and mortality rates [mortality/100 person-years, 95% confidence interval (CI)] were 18.1 (95% CI 9.4-34.8) and 5.4 (95% CI 4.1-7.2), i.e., the crude hazard ratio for death was 3.4 (95% CI: 1.7-7.0, p < 0.01). CONCLUSION: Self-assessed poor health status compared with non-poor health status as assessed by a single question was associated with a threefold increased long-term mortality in patients with endocarditis. POET ClinicalTrials.gov number, NCT01375257. TRIAL REGISTRY: POET ClinicalTrials.gov number, NCT01375257.

Inhibition of KV7 Channels Protects the Rat Heart against Myocardial Ischemia and Reperfusion Injury.

The voltage-gated KV7 (KCNQ) potassium channels are activated by ischemia and involved in hypoxic vasodilatation. We investigated the effect of KV7 channel modulation on cardiac ischemia and reperfusion injury and its interaction with cardioprotection by ischemic preconditioning (IPC). Reverse-transcription polymerase chain reaction revealed expression of KV7.1, KV7.4, and KV7.5 in the left anterior descending rat coronary artery and all KV7 subtypes (KV7.1-KV7.5) in the left and right ventricles of the heart. Isolated hearts were subjected to no-flow global ischemia and reperfusion with and without IPC. Infarct size was quantified by 2,3,5-triphenyltetrazolium chloride staining. Two blockers of KV7 channels, XE991 [10,10-bis(4-pyridinylmethyl)-9(10H)-anthracenone] (10 µM) and linopirdine (10 µM), reduced infarct size and exerted additive infarct reduction to IPC. An opener of KV7 channels, flupirtine (10 µM) abolished infarct size reduction by IPC. Hemodynamics were measured using a catheter inserted in the left ventricle and postischemic left ventricular recovery improved in accordance with reduction of infarct size and deteriorated with increased infarct size. XE991 (10 µM) reduced coronary flow in the reperfusion phase and inhibited vasodilatation in isolated small branches of the left anterior descending coronary artery during both simulated ischemia and reoxygenation. KV7 channels are expressed in rat coronary arteries and myocardium. Inhibition of KV7 channels exerts cardioprotection and opening of KV7 channels abrogates cardioprotection by IPC. Although safety issues should be further addressed, our findings suggest a potential role for KV7 blockers in the treatment of ischemia-reperfusion injury.

Impact of mandatory preoperative dental screening on post-procedural risk of infective endocarditis in patients undergoing transcatheter aortic valve implantation: a nationwide retrospective observational study.

Background: Guidelines recommend preoperative dental screening (PDS) prior to cardiac valve surgery, to reduce the incidence of prosthetic valve infective endocarditis (IE). However, limited data support these recommendations, particular in patients undergoing transcatheter aortic valve implantation (TAVI). We aimed to investigate the effect of mandatory PDS on risk of IE in patients undergoing TAVI. Methods: In this observational study, a total of 1133 patients undergoing TAVI in Western-Denmark from 2020 to 2022 were included. Patients were categorized based on two implemented PDS practices: mandatory PDS (MPDS group), and no referral for PDS (NPDS group). Outcome data were retrieved from Danish registries and confirmed using medical records. The primary outcome was incidence of IE. Secondary outcomes were all-cause mortality and composite outcome of all-cause mortality and IE. Findings: Of 568 patients in the MPDS group 126 (22.2%) underwent subsequent oral dental surgery, compared to 8 (1.4%) among 565 patients in the NPDS group. During a median follow-up of 1.9 years (interquartile range 1.4-2.5 years), 31 (2.7%) developed IE. The yearly incidence IE rate was 1.4% (0.8-2.3) and 1.5% (0.8-2.4) in MPDS and NPDS, respectively, p = 0.86. All-cause mortality rates were similar between groups (estimated 2-year overall mortality of 6.7% (4.8-9.2) vs. 4.7% (3.2-6.9), MPDS and NPDS, respectively, p = 0.15). Consistent findings were found in 712 propensity score-matched patients. Interpretation: Mandatory PDS did not demonstrate reduced risk of IE or all-cause mortality compared to targeted PDS in patients undergoing TAVI. Funding: The funder had no role in the study design, data management, or writing.

Association Between Vegetation Size and Outcome in the Partial Oral Antibiotic Endocarditis Treatment Trial.

Step-down oral antibiotic therapy is associated with a non-inferior long-term outcome compared with continued intravenous antibiotic therapy in the treatment of left-sided infective endocarditis. We aimed to analyze whether step-down oral therapy compared with continued intravenous antibiotic therapy is also associated with a non-inferior outcome in patients with large vegetations (vegetation length ≥ 10 mm) or among patients who underwent surgery before step-down oral therapy. We included patients without presence of aortic root abscess at diagnosis from the POET (Partial Oral Antibiotic Endocarditis Treatment) study. Multivariable Cox regression analyses were used to find associations between large vegetation, cardiac surgery, step-down oral therapy, and the primary end point (composite of all-cause mortality, unplanned cardiac surgery, embolic event, or relapse of positive blood cultures during follow-up). A total of 368 patients (age 68 ± 12, 77% men) were included. Patients with large vegetations (n = 124) were more likely to undergo surgery compared with patients with small vegetations (n = 244) (65% vs 20%, p <0.001). During a median 1,406 days of follow-up, 146 patients reached the primary end point. Large vegetations were not associated with the primary end point (hazard ratio 0.74, 95% confidence interval 0.47 to 1.18, p = 0.21). Step-down oral therapy was non-inferior to continued intravenous antibiotic in all subgroups when stratified by the presence of a large vegetation at baseline and early cardiac surgery. Step-down oral therapy is safe in the presence of a large vegetation at diagnosis and among patients who underwent early cardiac surgery.

Cardioprotective effect of combination therapy by mild hypothermia and local or remote ischemic preconditioning in isolated rat hearts.

A multitargeted strategy to treat the consequences of ischemia and reperfusion (IR) injury in acute myocardial infarction may add cardioprotection beyond reperfusion therapy alone. We investigated the cardioprotective effect of mild hypothermia combined with local ischemic preconditioning (IPC) or remote ischemic conditioning (RIC) on IR injury in isolated rat hearts. Moreover, we aimed to define the optimum timing of initiating hypothermia and evaluate underlying cardioprotective mechanisms. Compared to infarct size in normothermic controls (56 ± 4%), mild hypothermia during the entire or final 20 min of the ischemic period reduced infarct size (34 ± 2%, p < 0.01; 35 ± 5%, p < 0.01, respectively), while no reduction was seen when hypothermia was initiated at reperfusion (51 ± 4%, p = 0.90). In all groups with effect of mild hypothermia, IPC further reduced infarct size. In contrast, we found no additive effect on infarct size between hypothermic controls (20 ± 3%) and the combination of mild hypothermia and RIC (33 ± 4%, p = 0.09). Differences in temporal lactate dehydrogenase release patterns suggested an anti-ischemic effect by mild hypothermia, while IPC and RIC preferentially targeted reperfusion injury. In conclusion, additive underlying mechanisms seem to provide an additive effect of mild hypothermia and IPC, whereas the more clinically applicable RIC does not add cardioprotection beyond mild hypothermia.