Prosthetic valve endocarditis

Homograft Aortic Root Replacement for Destructive Prosthetic Valve Endocarditis: Results in the Current Era

Background: Destructive aortic prosthetic valve endocarditis portends a high morbidity and mortality, and requires complex high-risk surgery. Homograft root replacement is the most radical and biocompatible operation and, thus, the preferred option. Methods: A retrospective analysis was conducted on 61 consecutive patients who underwent a cardiac reoperation comprising homograft aortic root replacement since 2010. The probabilities of survival were calculated with the Kaplan-Meier method, whereas multivariable regression served to outline the predictors of adverse events. The endpoints were operative/late death, perioperative low cardiac output and renal failure, and reoperations. Results: The operative (cumulative hospital and 30-day) mortality was 13%. The baseline aspartate transaminase (AST) and associated mitral procedures were predictive of operative death (p = 0.048, OR [95% CIs] = 1.03 [1-1.06]) and perioperative low cardiac output, respectively (p = 0.04, OR [95% CIs] = 21.3 [2.7-168.9] for valve replacement). The latter occurred in 12 (20%) patients, despite a normal ejection fraction. Survival estimates (±SE) at 3 months, 6 months, 1 year, and 3 years after surgery were 86.3 ± 4.7%, 82.0 ± 4.9%, 75.2 ± 5.6, and 70.0 ± 6.3%, respectively. Survival was significantly lower in the case of AST ≥ 40 IU/L (p = 0.04) and aortic cross-clamp time ≥ 180 min (p = 0.01), but not when excluding operative survivors. Five patients required early (two out of the five, within 3 months) or late (three out of the five) reoperation. Conclusions: Homograft aortic root replacement for destructive prosthetic valve endocarditis can currently be performed with a near 90% operative survival and reasonable 3-year mortality and reoperation rate. AST might serve to additionally stratify the operative risk.

Infection of Transcatheter Valvular Devices

PURPOSE OF REVIEW

This review explores the epidemiology, clinical traits, and diagnosis of Transcatheter Aortic Valve Replacement-Associated Infective Endocarditis (TAVR-IE) and mitral transcatheter edge-to-edge repair infective endocarditis (TEER-IE), focusing on a multimodal imaging approach. It addresses the rising prevalence of TAVR and TEER, emphasizing the need to understand long-term complications and clinical consequences, which poses significant challenges despite advancements in valve technology.

RECENT FINDINGS

Studies report a variable incidence of TAVR-IE and TEER-IE influenced by diverse patient risk profiles and procedural factors. Younger age, male gender, and certain comorbidities emerge as patient-related risk factors. Procedure-related factors include intervention location, valve type, and technical aspects. Microbiologically, Staphylococcus aureus, Viridans Group Streptococcus, and Enterococcus are frequently encountered pathogens. TAVR-IE and TEER-IE diagnosis involves a multimodal imaging approach due to limitations in echocardiography. Blood cultures and imaging aid identification, with Fluorescence in situ hybridization is showing promise. Treatment encompasses medical management with antibiotics and, when necessary, surgical intervention. The management approach requires a multidisciplinary "Endocarditis Team." This review underscores the need for continued research to refine risk prediction, enhance diagnostic accuracy, and optimize management strategies for TAVR-IE, considering the evolving landscape of transcatheter interventions.

Infective endocarditis after surgical aortic or mitral valve replacement: A nationwide population-based study

OBJECTIVE

Evidence regarding the incidence of prosthetic valve endocarditis and its association with the use of mechanical or biologic prosthetic valves is limited.

METHODS

Patients who underwent aortic or mitral valve replacement in the years 2000 to 2017 were identified from Taiwan's National Health Insurance Research Database and grouped according to the type of prosthesis used (mechanical or biologic). Propensity score matching was performed to reduce confounding.

RESULTS

A total of 22,844 patients were included, with 11,950 (52.2%) and 10,934 (47.8%) in the mechanical prosthesis and biologic prosthesis groups, respectively. After matching, each group contained 5441 patients. During follow-up, patients with a biologic prosthesis had a significantly higher risk of infective endocarditis (IE) than those with a mechanical valve (3.4% vs 1.9%; subdistribution hazard ratio, 1.78; 95% CI, 1.40-2.26). Moreover, biologic prostheses were associated with greater risks of all-cause mortality and redo valve surgery, but lesser risks of ischemic stroke, hemorrhagic stroke, major bleeding, and gastrointestinal bleeding. In subgroup analysis, biologic prostheses were consistently associated with a greater risk of IE in all subgroups, specifically single-valve replacement-aortic, single-valve replacement-mitral, double-valve replacement, active IE (IE diagnosed during index hospitalization), any IE (active or old), and not having a history of IE.

CONCLUSIONS

In this nationwide population-based retrospective cohort study, biologic prosthesis use was associated with a greater risk of IE during follow-up compared with mechanical valve use. However, mechanical valve use was associated with a greater risk of ischemic stroke and hemorrhagic complications.

Multiple Recurrent Infective Endocarditis Secondary to Streptococcus mitis Bacteremia Despite Proper Antibiotic and Surgical Treatment

Infective endocarditis (IE) is a rare and potentially fatal disease. It is an infection of the endocardium of the heart and heart valves. One of the major complications faced by patients who have recovered from a first episode of IE is recurrent IE. Risk factors for recurrent IE include intravenous (IV) drug use, prior episodes of IE, poor dentition, recent dental procedures, male gender, age over 65, prosthetic heart valve endocarditis, chronic dialysis, positive valve culture(s) obtained at the time of surgical intervention, and persistent postoperative fever. We present a case of a 40-year-old male with a history of former IV heroin use who experienced multiple episodes of recurrent IE caused by the same pathogen, Streptococcus mitis. This recurrence occurred despite the patient completing the appropriate course of antibiotic therapy, undergoing valvular replacement, and maintaining drug abstinence for two years. This case highlights the challenges associated with identifying the source of infection and emphasizes the need to develop guidelines for surveillance and prophylaxis against recurrent IE.

Surgical Outcomes After Reconstruction of the Aortomitral Curtain

Repair of concomitant aortic and mitral valvular disease with involvement of the aortomitral curtain requires a technically complex operation colloquially termed the commando procedure. Surgical outcomes of this procedure are not well described. The objective of this study was to examine outcomes of the commando procedure at our center. We identified all patients undergoing concomitant aortic and mitral valve replacements from 2004-2021. Of 363 patients, 41 underwent reconstruction of the aortomitral curtain. Survival analysis and multivariable modeling were used to examine outcomes and risk factors for mortality. The median age was 52 (IQR 44-71) years. Preoperatively, 4 of 41 (9.8%) patients had renal failure, and 10 of 41 (24.4%) had a stroke. The most common surgical indication was endocarditis in 25 of 41 (61.0%) patients. 25 of 41 (61.0%) patients underwent redo sternotomy, and 23 of 41 (56.1%) had previous prosthetic valves. Operative mortality was 14 of 41 (34.1%), and 8 of 41 (9.5%) patients received a permanent pacemaker. Survival at 1, 3, and 5 years was 55.4% (95% confidence interval (CI), 40.6-75.5%), 50.3% (35.0-72.3%), and 37.7% (19.3-73.9%) respectively. Cox proportional hazards regression identified previous sternotomy (HR 4.76, 95% CI 1.21-18.73), and female gender (HR 1.39, 95% CI 1.17-13.82) as risk factors for mortality. Patients undergoing reconstruction of the aortomitral curtain represent a high-risk population with complex surgical indications. Due to high perioperative morbidity and mortality, this procedure should be performed only when necessary. Despite a high up front morbidity burden, outcomes remain favorable for patients who survive the initial hospitalization.

Microbiological etiology in prosthetic valve endocarditis: A nationwide registry study

BACKGROUND

Prosthetic valve endocarditis (PVE) is a feared complication after heart valve surgery. Studies on differences in bacteriology in various types of PVE are limited.

OBJECTIVES

This study aimed to investigate the microbiology of PVE depending on the type of prosthetic valve and timing of diagnosis.

METHODS

A retrospective study based on the Swedish Registry on Infective Endocarditis focusing on PVE was conducted. The cohort was divided into mechanical and bioprosthetic valves; into endocarditis localization in the aortic, mitral, or tricuspid valve; and into early and late PVE. The microbiology in these groups was compared. Predictors of Staphylococcus aureus as the cause of PVE were examined by multivariable logistic regression.

RESULTS

A total of 780 episodes of PVE in 749 patients were compared regarding the distribution of causative microbiological agents. The most common agents included alpha-hemolytic streptococci (29%), S. aureus (22%), enterococci (14%), coagulase-negative staphylococci (CoNS) (12%), and Cutibacterium acnes (6%). S. aureus was more commonly found on mechanical valves compared to bioprosthetic ones (36% vs. 17%, p < 0.001) whereas alpha-hemolytic streptococci, enterococci, and CoNS were more common on bioprosthetic valves. There were no significant differences in the microbiology of PVE affecting mitral or aortic valves or in cases of early and late PVE. Predictors for S. aureus as the cause of PVE were end-stage renal disease, intravenous drug use, mechanical valve, and tricuspid localization of endocarditis.

CONCLUSIONS

The type of prosthetic heart valve is associated with the causative pathogen. Patients with mechanical valves are more likely to have PVE caused by S. aureus.

The prevalence of persistent bacteraemia in patients with a non-staphylococcal infective endocarditis, a retrospective cohort study

BACKGROUND

Current guidelines on the management of infective endocarditis (IE) recommend follow-up blood cultures (FUBCs) to identify persistent bacteraemia, as this has prognostic value and guides treatment decisions. While persistent bacteraemia frequently occurs in Staphylococcus aureus bacteraemia and IE, its prevalence and impact in non-staphylococcal IE is largely unknown. We determined prevalence and prognostic value of persistent bacteraemia in non-staphylococcal IE.

METHODS

We conducted a retrospective analysis of all patients diagnosed with definite non-staphylococcal endocarditis according to the modified Duke Criteria in two university hospital endocarditis registries We determined the prevalence and prognostic value of persistent bacteraemia.

RESULTS

Of the included 159 patients 70 (44%) had prosthetic valve endocarditis (PVE). A median number of two [IQR 1-3] FUBCs were taken during the first week, with 134/159 (84%) having at least one FUBC in the first four days. Seven patients (4,4%) had persistent bacteraemia 48 h after start of antibiotic treatment: 5/70 patients (7.1%) with PVE and 2/89 (2.2%) with native valve endocarditis. Among 97 patients with streptococcal IE, nine patients with HACEK IE and six patients with Cutibacterium IE, no persistent bacteraemia was observed. Enterococcus faecalis was the causative microorganism in five patients with persistent bacteraemia, the other two had non-HACEK Gram-negative endocarditis.

CONCLUSION

Persistent bacteraemia in non-staphylococcal endocarditis was rare. It was more frequently observed in PVE and was restricted to more resilient microorganisms such as enterococci and non-HACEK Gram-negative bacteria. Routine collection of FUBCs in patients with streptococcal endocarditis has a low yield and may require re-evaluation.

Recurrent Staphylococcus capitis Prosthetic Valve Endocarditis Presenting With ST-Segment Elevation Myocardial Infarction: A Case Report

We report a case of ST-elevation myocardial infarction (STEMI) due to septic emboli secondary to Staphylococcus capitis endocarditis in a 32-year-old male patient with a past medical history of infectious endocarditis requiring mechanical aortic, mitral and tricuspid valve replacement presented with sharp chest pain and shortness of breath. Electrocardiogram demonstrated an acute inferior STEMI.

Coronary angiography revealed occlusion of the terminal left anterior descending (LAD) artery associated with a large apical wrap-around segment exhibiting TIMI 0 flow. Primary angioplasty was not performed given the distal location of the embolus. Clinical suspicion for septic or thrombotic coronary artery embolism was high given the patient’s history of mechanical valve prosthesis and in the setting of sub-therapeutic INR. Transesophageal echocardiography revealed a new mobile echodensity on the mitral prosthesis consistent with vegetation. S. capitis was isolated from blood cultures, confirming the diagnosis of endocarditis.

S. capitis is a rare cause of prosthetic valve endocarditis and should remain in the differential of septic coronary artery embolism among patients with features of infectious endocarditis.

The role of antiaggregant agents and anticoagulants in the prevention of aortic valve endocarditis: A double-cohort retrospective study

Objective

Antiaggregants (Ag) could prevent infective endocarditis (IE) in preclinical studies. In this study we investigated whether Ag or anticoagulants (Ac) were also protective in humans.

Methods

In part I we determined the incidence of IE of bioprosthetic aortic valves (PVE) in 333 consecutive patients who underwent aortic valve replacement for noninfective aortic insufficiency between 2009 and 2019. In part II we retrospectively analyzed data of 137 patients who had developed IE of the native aortic valve (NVE) between 2007 and 2015. Multivariable Fine–Gray and logistic regression models were used to investigate associations between Ag and Ac therapy and IE.

Results

Sixteen of 333 (4.8%) aortic valve replacement recipients developed PVE after a median of 3.72 years. There was no association between Ag and PVE, whereas Ac was associated with a higher IE occurrence (no association for vitamin K antagonists but significant for fondaparinux or low molecular-weight heparins; hazard ratio, 4.61; 95% CI, 1.01-21.9). In contrast, among the 137 patients in part II, vitamin K antagonists (odds ratio [OR], 7.52; 95% CI, 2.51-22.6), double antiplatelet therapy (OR, 44.3; 95% CI, 4.83-407), novel oral Ac (OR, 4.17; 95% CI, 1.15-15.1), and fondaparinux or low molecular-weight heparins (OR, 9.87; 95% CI, 1.81-53.9), but not acetylsalicylic acid, were associated with NVE.

Conclusions

Ac were associated with IE in both cohorts, whereas Ag were not associated with PVE. This might reflect differences in the studied populations, with Ag and Ac being prescribed for conditions associated with long-term IE risk in the NVE cohort. Therefore, determining the potential protective effect of Ag and Ac will necessitate further well–controlled studies.

Catheter-based Closure of a Post-infective Aortic Paravalvular Pseudoaneurysm Fistula With Severe Regurgitation After Two Valve Replacement Surgeries: A Case Report

Backgsround: Infective endocarditis (IE) of prosthetic valves is a dire complication of cardiac valve replacement surgery and is associated with high rates of morbidity and mortality. Case Summary: A 72-year-old woman with multiple comorbidities underwent surgical replacement of the aortic valve with a mechanical prosthetic valve after recurrent IE. After 10 years, IE recurred and the mechanical valve was surgically replaced with a bioprosthetic valve. Ten years later, severe heart failure developed due to severe paravalvular leak (PVL) caused by an aortic annulus abscess complicated by a paravalvular pseudoaneurysm fistula (PPF). The patient was deemed at prohibitive surgical risk and a catheter-based PVL closure procedure was planned. However, the interventional procedure was delayed several months due to the Covid-19 pandemic with progressive heart failure worsening. Despite an acute satisfactory result of the PPF transcatheter closure and a significant clinical improvement, the patient died 10 months later due to multiorgan failure. It is likely that this was due, at least in part, to the long treatment delay caused by the unprecedented strain on the healthcare system. Discussion: In patients at high surgical risk, early diagnosis and prompt interventional treatment of severe PVL are crucial for improving expectancy and quality of life. However, the recent outbreak of COVID-19 caused deferral of elective and semi-elective structural heart disease procedures (SHD) as in our case. Thus, a proactive and vigilant stance on managing SHD should be a priority even in the context of the COVID-19 pandemic.

A case series of medically managed Candida parapsilosis complex prosthetic valve endocarditis

Background

In recent years, Candida parapsilosis is recognized as a species complex and is composed of Candida parapsilosis sensu stricto, Candida orthopsilosis and Candida metapsilosis. Candida parapsilosis complex prosthetic valve endocarditis (PVE) is rare and the survival rate is still low despite of optimal therapeutic strategies. In our report, it is novel to report cases as Candida parapsilosis complex PVE at species and identify Candida parapsilosis using MALDI-TOF MS.

Case presentation

A series of 4 cases of Candida parapsilosis complex PVE from our institution was reported. Three were infected by Candida parapsilosis sensu stricto and one was infected by Candida metapsilosis. The condition of two cases got better and the other died.

Conclusions

More attention should be paid to Candida parapsilosis complex PVE and early diagnosis and prompt antibiotic therapy may play a role in the treatment for Candida parapsilosis complex PVE. It is recommended to identify Candida parapsilosis complex at species level and MALDI-TOF MS as an easy, fast and efficient identification method is worth promoting in clinical microbiology

Infective Endocarditis After Surgical and Transcatheter Aortic Valve Replacement: A State of the Art Review

Prosthetic valve endocarditis (PVE) after surgical aortic valve replacement and transcatheter aortic valve replacement (TAVR) carries significant morbidity/mortality. Our review aims to compare incidence, predisposing factors, microbiology, diagnosis, management, and outcomes of PVE in surgical aortic valve replacement/TAVR patients. We searched PubMed and Embase to identify published studies from January 1, 2015 to March 13, 2020. Key words were indexed for original reports, clinical studies, and reviews. Reports were evaluated by 2 authors against a priori inclusion/exclusion criteria. Studies were included if they reported incidence and outcomes related to surgical aortic valve replacement/TAVR PVE and excluded if they were published pre-2015 or included a small population. We followed the Cochrane methodology and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for all stages of the design and implementation. Study quality was based on the Newcastle-Ottawa Scale. Thirty-three studies with 311 to 41 025 patients contained relevant information. The majority found no significant difference in incidence of surgical aortic valve replacement/TAVR PVE (reported as 0.3%-1.2% per patient-year versus 0.6%-3.4%), but there were key differences in pathogenesis. TAVR has a specific set of infection risks related to entry site, procedure, and device, including nonstandardized protocols for infection control, valve crimping injury, paravalvular leak, neo-leaflet stress, intact/calcified native leaflets, and intracardiac hardware. With the expansion of TAVR to lower risk and younger patients, a better understanding of pathogenesis, patient presentation, and guideline-directed treatment is paramount. When operative intervention is necessary, mortality remains high at 20% to 30%. Unique TAVR infection risks present opportunities for PVE prevention, therefore, further investigation is imperative.

Stroke Risk Following Infection in Patients with Continuous-Flow Left Ventricular Assist Device

BACKGROUND

Infection has been associated with stroke in patients with left ventricular assist devices (LVAD); however, little data exist on the timing, type and mortality impact of infection-related stroke.

METHODS

Prospectively collected data of HeartMate II (N = 332) and HeartWare (N = 70) LVAD patients from a single center were reviewed. Only strokes (ischemic or hemorrhagic) that occurred within 6 weeks following a LVAD infection were considered in analyses. The association between LVAD infections (wound, pump pocket, driveline and/or bloodstream infection [BSI]), specific pathogens and ischemic and hemorrhagic strokes was evaluated using multivariable logistic regression analysis. The impact of infection-related stroke on cumulative survival was assessed using Kaplan-Meier analysis.

RESULTS

Of 402 patients, LVAD infection occurred in 158 (39%) including BSI in 107 (27%), driveline infection in 67 (17%), wound infection in 31 (8%) and pump pocket infection in 24 (6%). LVAD infection-related stroke occurred in 20/158 (13%) patients in a median of 4 days (0-36 days) from documented infection. In multivariable analysis, ischemic stroke was associated with wound infection (aOR 9.0, 95% CI 2.4-34.0, P = 0.001) and BSI (aOR 7.7, 95% CI 0.9-66.0, P = 0.064), and hemorrhagic stroke was associated with BSI in 100% of cases (P = 0.01). There was no association with driveline or pump pocket infection. The cumulative survival rate among patients with infection-related stroke was significantly lower compared to those with LVAD infection but no stroke (log-rank P < 0.001). There was a trend toward shorter stroke-free survival among patients with LVAD infection.

CONCLUSIONS

LVAD infections, particularly BSI, are significantly associated with stroke, and infection-related stroke conferred significantly lower cumulative survival.

Dehiscence of a Mechanical Aortic Valve Secondary to Culture-Negative Endocarditis Complicated by Acute Heart Failure

•

The authors describe culture-negative endocarditis causing mechanical AV dehiscence.

•

Early diagnosis and prompt surgical treatment are necessary.

•

TEE is useful in identifying the etiology of AR in this instance.

•

Pseudoaneurysm involving aortic homograft is rare and can occur without reinfection.

Infective endocarditis after transcatheter aortic valve implantation: a nationwide study

AIMS

Transcatheter aortic valve implantation (TAVI), now a common procedure to treat high-risk patients with severe aortic stenosis, has rapidly been expanding into younger and lower-risk populations, creating a need to better understand long-term outcome after TAVI. The aim of the present investigation was to determine the incidence, risk factors for, clinical presentation of, and outcome after prosthetic valve endocarditis (PVE) in patients treated with TAVI in a nationwide study.

METHODS AND RESULTS

Three registries were used: a national TAVI registry, a national diagnosis registry, and a national infective endocarditis registry. Combining these registries made it possible to perform a nationwide, all-comers study with independent and validated reporting of PVE in 4336 patients between 2008 and mid-2018. The risk for PVE after TAVI was 1.4% (95% confidence interval 1.0-1.8%) the first year and 0.8% (0.6-1.1%) per year thereafter. One-year survival after PVE diagnosis was 58% (49-68%), and 5-year survival was 29% (17-41%). Body surface area, estimated glomerular filtration rate <30 mL/min/1.73 m2, critical pre-operative state, mean pre-procedural valve gradient, amount of contrast dye used, transapical access, and atrial fibrillation were identified as independent risk factors for PVE. Staphylococcus aureus was more common in early (<1 year) PVE. Infection with S. aureus, root abscess, late PVE, and non-community acquisition was associated with higher 6-month mortality.

CONCLUSION

The incidence of PVE was similar to that of surgical bioprostheses. Compromised renal function was a strong risk factor for developing PVE. In the context of PVE, TAVI seems to be a safe option for patients.

CLINICAL TRIAL REGISTRATION

NCT03768180 (http://clinicaltrials.gov/).

Virulence of beta-hemolytic streptococci in infective endocarditis

BACKGROUND

Streptococci involved in infective endocarditis (IE) primarily comprise alpha- or non-hemolytic streptococci (ANHS). Moreover, beta-hemolytic streptococci (BHS) can be involved, and guidelines recommend the addition of gentamicin for the first 2 weeks of treatment and the consideration of early surgery in such cases. This study compared the morbidity and mortality associated with IE depending on the microorganisms involved (BHS, ANHS, staphylococci, and enterococci).

METHODS

We conducted a retrospective observational study between 2012 and 2017 in a single hospital in France. The endpoints were overall in-hospital mortality, 1-year mortality and the occurrence of complications.

RESULTS

We analyzed 316 episodes of definite IE including 150 (38%), 96 (25%), 46 (12%), and 24 cases (6%) of staphylococcal, ANHS, enterococcal, and BHS IE, respectively. In-hospital mortality was significantly higher in the staphylococcal (n = 40; 26.7%) and BHS groups (n = 6; 25.0%) than in the ANHS (n = 9; 9.4%) and enterococcal groups (n = 5; 10.9%) (all p < 0.01). The rates of septic shock and cerebral emboli were also higher in the BHS group than in the ANHS group [n = 7 (29.2%) vs. n = 3 (3.1%), p < 0.001; n = 7 (29.2%) vs. n = 12 (12.5%); p = 0.05, respectively].

CONCLUSION

This study confirmed that BHS IE has a more severe prognosis than ANHS IE. The virulence of BHS may be similar to that of staphylococci, justifying increased monitoring of these patients and more 'aggressive' treatments such as early surgery.

Methicillin-Resistant Staphylococcus aureus Prosthetic Valve Endocarditis: Pathophysiology, Epidemiology, Clinical Presentation, Diagnosis, and Management

Staphylococcus aureus prosthetic valve endocarditis (PVE) remains among the most morbid bacterial infections, with mortality estimates ranging from 40% to 80%. The proportion of PVE cases due to methicillin-resistant Staphylococcus aureus (MRSA) has grown in recent decades, to account for more than 15% of cases of S. aureus PVE and 6% of all cases of PVE. Because no large studies or clinical trials for PVE have been published, most guidelines on the diagnosis and management of MRSA PVE rely upon expert opinion and data from animal models or related conditions (e.g., coagulase-negative Staphylococcus infection). We performed a review of the literature on MRSA PVE to summarize data on pathogenic mechanisms and updates in epidemiology and therapeutic management and to inform diagnostic strategies and priority areas where additional clinical and laboratory data will be particularly useful to guide therapy. Major updates discussed in this review include novel diagnostics, indications for surgical management, the utility of aminoglycosides in medical therapy, and a review of newer antistaphylococcal agents used for the management of MRSA PVE.

Predictors of surgical outcome in isolated prosthetic mitral valve endocarditis

Background Most previous studies dealing with predictors of surgical outcome in prosthetic valve endocarditis included patients with aortic and/or mitral valve prostheses. Here, we concentrate on isolated prosthetic mitral endocarditis due to heterogeneity of epidemiological data, anatomical factors, and surgical techniques between mitral, prosthetic mitral, and aortic endocarditis between prosthetic mitral and prosthetic aortic endocarditis. Methods Data of 40 patients reoperated upon due to isolated prosthetic mitral endocarditis between July 2015 and March 2017 were retrospectively collected and analyzed. Results Independent predictors of major postoperative complications on multivariate analysis were: no blood cultures before referral (odds ratio 6.36, 95% confidence interval: 1.44-28.15), inadequate response to medical treatment (odds ratio 11.38, 95% confidence interval: 1.29-100.25), and serum creatinine ≥2.0 mg·dL^-1 (odds ratio 4.56, 95% confidence interval: 1.07-19.36). Independent predictors of hospital mortality were: congestive heart failure (odds ratio 30.91, 95% confidence interval: 2.02 to 473.87), embolization (odds ratio 18.24, 95% confidence interval:1.94-171.91), peri-annular extension of infection (odds ratio 12.68, 95% confidence interval: 1.30-123.43), serum creatinine on admission > 2 mg·dL^-1 (odds ratio 9.67, 95% confidence interval: 1.97-47.48), and early prosthetic valve endocarditis (odds ratio 7.80, 95% confidence interval: 1.35-45.00). EuroSCORE II > 5.93% was associated with the highest predictive value for hospital mortality (area under the curve 0.813). Conclusion Certain factors can predict morbidity and mortality in surgery for isolated mitral prosthetic valve endocarditis. EuroSCORE II has a good ability to predict hospital mortality in surgery for mitral prosthetic valve endocarditis.

Outcomes of Reoperative Valve Replacement in Patients with Prosthetic Valve Endocarditis: A 20-Year Experience

Background

Prosthetic valve endocarditis (PVE) is a serious complication of cardiac valve replacement, and many patients with PVE require reoperation. The aim of this study was to review our institutional 20-year experience of surgical reoperative valve replacement in patients with PVE.

Methods

A retrospective study was performed on 84 patients (mean age, 54.8±12.7 years; 51 males) who were diagnosed with PVE and underwent reoperative valve replacement from January 1995 to December 2016.

Results

PVE was found in 1 valve in 61 cases (72.6%), and in 2 or more valves in 23 cases (27.4%). The median follow-up duration was 47.3 months (range, 0 to 250 months). Postoperative complications occurred in 39 patients (46.4%). Reinfection occurred in 6 cases, all within 1 year. The freedom from reinfection rate at 5 years was 91.0%±3.5%. The overall survival rates at 5 and 10 years were 64.4%±5.8% and 54.3%±7.3%, respectively. In stepwise multivariable Cox proportional hazard models, older age (hazard ratio [HR], 1.48; 95% confidence interval [CI], 1.05 to 2.10; p=0.027) and cardiopulmonary bypass (CPB) time (HR, 1.03; 95% CI, 1.00 to 1.01; p=0.033) emerged as independent risk factors for death.

Conclusion

Older age and a longer CPB time were associated with an increased risk of overall mortality in PVE patients.

Afebrile Pannus-Induced Blood Culture-Negative Mechanical Valve Endocarditis

The diagnosis of prosthetic valve endocarditis may be challenging in patients with an atypical clinical presentation. Virtually all infections associated with mechanical prosthetic valves are localized to the prosthesis-tissue junction at the sewing ring and are accompanied by tissue destruction around the prosthesis. Because the orifice of the mechanical prosthetic valve is made of metal and pyrolytic carbon, which do not enable the adherence of microorganisms, any vegetation originating from the interior of the valve orifice is usually rare. Here we present a rare case of pannus-induced mechanical prosthetic valve endocarditis that was difficult to diagnose.

Resistance to infection of long-term cryopreserved human aortic valve allografts

OBJECTIVE

To analyze the in vitro antimicrobial activity of 3 antibiotic regimens (group A, gentamicin-piperacillin-vancomycin-metronidazole-amphotericin B; group B, gentamicin-piperacillin-flucloxacillin-metronidazole-amphotericin B; and group C, meropenem-vancomycin-tobramycin-colistin-amphotericin B) used in the processing of cryopreserved human ascending aortic tissue and aortic valves against Staphylococcus epidermidis and Staphylococcus aureus. The results were additionally compared with the infection resistance of cryopreserved ascending aortic tissue against Escherichia coli and Pseudomonas aeruginosa.

MATERIALS

Each of 10 cryopreserved human allografts (CHAs) was divided into 25 pieces (separating aortic wall and valve). Eighteen segments were microbiologically tested, and 7 pieces underwent scanning electron microscopy. A bacterial solution (4 mL; optical density, 0.20 ± 0.02) was used for contamination. After incubation, the optical density of the solution was measured. CHAs underwent sonication to release viable adherent bacteria. The number of attached bacteria was quantified by the colony forming units per square centimeter of CHA surface.

RESULTS

Antibiotic regimen groups B and C were more efficient than group A in eradicating gram-positive organisms adherent to the aortic wall (P < .001). Group C showed enhanced resistance against E coli compared with group A or B (P < .001), whereas group B appeared to be more effective against P aeruginosa (P < .001). With reference to each antibiotic regimen, ascending aortic tissue showed significantly less bacterial contamination with staphylococcal bacteria than valve grafts (P ≤ .01).

CONCLUSIONS

CHAs possess antibacterial activity despite long-term storage over 5 years. Antibiotic combinations applied during CHA processing have a significant influence on their infection resistance. Ascending aortic tissue shows a significantly enhanced bacterial resistance against staphylococcal bacteria compared with aortic valves.

Ventricular tachycardia: ominous sign of devastating prosthetic aortic valve dehiscence

Prosthetic valve endocarditis (PVE) is the most feared complication after valve implantation. It usually results in substantial morbidity and mortality in the postoperative period. An adverse effect on the annulus can cause conduction disturbances in the atrioventricular (AV) node, resulting in a high-degree AV block. This study describes a case of PVE that predominantly presented with sustained monomorphic ventricular tachycardia, which indicated a severe clinical course of PVE caused by a significant displacement of the aortic valve prosthesis. In our opinion, a very pronounced flap valve motion of the dehisced valve probably caused, in the critical moment, coronary artery blood flow limitation by means of coronary microembolization, which produced temporary ischemia and provoked sustained ventricular tachycardia. Furthermore, disturbances of rhythm such as ventricular tachycardia in the setting of endocarditis indicate a high-risk condition and should mandate fast and thorough noninvasive diagnostic procedures to obtain correct diagnosis even in the case of mild, slowly progressing disease.

Outcomes of nonpledgeted horizontal mattress suture technique for mitral valve replacement

BACKGROUND

Most surgeons favor the pledgeted suture technique for heart valve replacements because they believe it decreases the risk of paravalvular leak (PVL). We hypothesized that the use of nonpledgeted rather than pledgeted sutures during mitral valve replacement (MVR) may decrease the incidence of prosthetic valve endocarditis (PVE) and risk of a major PVL.

METHODS

We analyzed 263 patients, divided into 175 patients who underwent MVR with nonpledgeted sutures from January 2003 to December 2013 and 88 patients who underwent MVR with pledgeted sutures from January 1995 to December 2001. We compared the occurrence of PVL and PVE between these groups.

RESULTS

In patients who underwent MVR with or without tricuspid valve surgery and/or a Maze operation, PVL occurred in 1.1% of the pledgeted group and 2.9% of the nonpledgeted group. The incidence of PVE was 2.9% in the nonpledgeted group and 1.1% in the pledgeted group. No differences were statistically significant.

CONCLUSION

We suggest that a nonpledgeted suture technique can be an alternative to the traditional use of pledgeted sutures in most patients who undergo MVR, with no significant difference in the incidence of PVL.

Surgical treatment of late aortic prosthetic valve endocarditis: 19 years' experience

AIM OF THE STUDY

We retrospectively analyzed the results of operations conducted for aortic prosthetic valve endocarditis in a single center over 19 years.

MATERIAL AND METHODS

From February 1992 to January 2011, we performed operations on 27 patients with aortic prosthetic valve endocarditis. Seventeen patients (63.0%) were male, and the mean age was 39.1 ± 14.2 (16-67) years. Blood cultures were positive in 11 patients (40.7%), and the most commonly identified microorganism was Streptococcus (7 patients, 25.9%). The mean duration of follow-up was 8.6 ± 4.7 years (0.5-18.2), adding up to a total of 136.9 patient/years.

RESULTS

Forty procedures were performed on these 27 patients. The most commonly performed procedure was aortic valve replacement with a prosthetic valve - 16 patients (59.3%). Fifteen patients were operated on during the active phase of infection. In-hospital mortality was observed in 11 patients (40.7%). Postoperatively, 12 patients (44.4%) had low cardiac output, 3 (11.1%) suffered from a heart block; none of them required permanent pacemaker implantation. The actuarial survival for 1 and 5 years was 55.6 ± 9.6% and 47.6 ± 9.7%, respectively.

CONCLUSIONS

Prosthetic valve endocarditis of the aortic valve is a challenging situation for the surgeon. The surgical treatment carries a high mortality rate and long-term survival is low. Among the survivors, however, recurrence and the need for reoperation are unlikely.

Prosthetic valve endocarditis after transcatheter aortic valve implantation: the incidence in a single-centre cohort and reflections on clinical, echocardiographic and prognostic features

AIMS

Transcatheter aortic valve implantation (TAVI) has recently developed into an accepted alternative to conventional surgery in high-risk patients. According to current data, post-TAVI prosthetic valve endocarditis (PVE) seems to occur very rarely.

METHODS AND RESULTS

We followed the first 180 consecutive patients who underwent TAVI at our institution to assess safety and efficacy of the procedure. During follow-up (median, 319 days), PVE was seen more frequently than expected. By applying modified Duke criteria five cases could be confirmed (four early-onset and one late-onset PVE, four cases with "definite diagnosis" and one with "possible diagnosis") representing an estimated PVE incidence of 3.4% at one year. Two patients died subsequently. Clinical summaries of all cases are reported and compared to previously published case reports.

CONCLUSIONS

According to our hypothesis, PVE might be particularly difficult to diagnose after TAVI, whereas TAVI-specific elderly patients might be exceptionally vulnerable. There exists little experience of TEE interpretation in post-TAVI endocarditis which should possess unique characteristics regarding, e.g., valve dehiscence or abscess formation. Therefore, echocardiography as a diagnostic tool often remains initially inconclusive. Because of incongruence between prosthetic device and calcified native aortic valve, some degree of paravalvular leak is common after TAVI. These paravalvular leaks as a nidus for infection, advanced age and abundant comorbidities might predispose TAVI patients for infective endocarditis.

Bloodstream infections occurring in patients with percutaneously implanted bioprosthetic pulmonary valve: a single-center experience

BACKGROUND

Percutaneous pulmonary valve implantation using a stent-based bioprosthetic valve provides an alternative to surgery in select patients. Systemic infections in Melody valve-implanted patients with and without identified valve involvement have been reported, yet the incidence is unknown, and risk factors remain unidentified.

METHODS AND RESULTS

Between 2007 and 2012, a total of 147 consecutive patients with congenital heart disease underwent Melody percutaneous pulmonary valve implantation at our institution. Demographic and clinical variables were collected at baseline and at follow-up and analyzed as predictors. The occurrence of bloodstream infection (BSI), defined as a bacterial infection treated with ≥4 weeks of antibiotics, served as our primary outcome. The mean age at implantation for the study population was 21.5±11 years, and tetralogy of Fallot was the cardiac condition in 59%. During a median follow-up of 19 months, 14 patients experienced BSI (9.5%; 95% confidence interval, 5.3%-15%). Of these, 4 (2.7%) patients had Melody valve endocarditis. Two patients died during the event, neither of whom had known valve involvement. The median procedure to infection time was 15 months (range, 1-56). In univariate analysis, male sex, previous endocarditis, in situ stents in the right ventricular outflow tract, and presence of outflow tract irregularities at the implant site were associated with BSI occurrence.

CONCLUSIONS

In this cohort, 9.5% of patients who underwent Melody percutaneous pulmonary valve implantation experienced subsequent BSI, occurring 1 to 56 months after implant, and 2.7% of patients had prosthetic endocarditis. Our findings suggest that patient and nonvalve anatomic factors may be associated with BSI after percutaneous pulmonary valve implantation.

Technique of managing periprosthetic leakage due to mitral prosthetic valve endocarditis: report of a case

A patient with multiple leaks caused by active mitral prosthetic valve endocarditis with an annular abscess underwent repeat mitral valve replacement. To secure the new mitral prosthesis, sutures were placed through the healthy interatrial septal wall from right to left at the posteromedial region and then to the new prosthetic valve sewing cuff. In the anterolateral region, sutures were placed through the reconstructed annulus after debridement of the abscess and then reinforced with a pericardial xenograft patch. Postoperatively, the perivalvular leakage stopped and the patient recovered uneventfully.

A surgical case of prosthetic valve endocarditis with a difficult diagnosis

Early diagnosis and treatment of prosthetic valve endocarditis (PVE) is important because it has a high mortality rate. We report a case of PVE which was difficult to diagnose. A 36-year-old man, who had undergone an aortic valve replacement (AVR) 7 years prior, was hospitalized with a high fever of unknown origin. We could not detect a stuck valve, vegetations or abscesses using echocardiography, and the peak aortic transvalvular pressure gradient had increased to 81 mmHg. We suspected PVE and initiated intravenous antibiotic therapy immediately. On day 5, echocardiography demonstrated an abnormal shadow directly under the prosthesis, and we definitively diagnosed PVE and performed an operation. Intraoperatively, the prosthesis was not vegetative, but the left ventricular outflow tract was filled with vegetation that was nearly obstructing it. After dissecting the infectious focus, we performed a re-AVR. Postoperative echocardiography showed that the peak left ventricular aortic pressure gradient decreased to 30 mmHg. Obstructive vegetation is difficult to diagnose by preoperative echocardiography.

Streptococcus pneumoniae endocarditis on replacement aortic valve with panopthalmitis and pseudoabscess

A 63-year-old woman with a previous episode of Streptococcus agalactiae endocarditis requiring a bioprosthetic aortic valve replacement presented with a short history of malaise, a right panopthalmitis with a Roth spot on funduscopy of the left eye and Streptococcus pneumoniae grown from vitreous and aqueous taps as well as blood cultures. She developed first degree heart block and her ECG was suggestive of an aortic root abscess. This gradually resolved over 6 weeks, during which she was treated with intravenous antibiotics. After careful consideration, it is likely that what was thought to be an aortic root abscess was instead an area of perivalvular inflammation.

Mycobacterial prosthetic valve endocarditis

Prosthetic valve endocarditis (PVE) due to mycobacteria is a rare but frequently fatal complication that may occur early after the surgical procedure, or even years later. Infection has been described with both mechanical and biologic valvular prosthesis. The most commonly implicated mycobacterial species belong to the rapid-grower group (M. chelonei, M. fortuitum, and M. abscessus) of nontuberculous mycobacteria (NTM). The source of infection in this context is thought to be nosocomial, likely related to preoperative or intraoperative contamination of the prosthesis by contact with aqueous solutions containing the organisms. These infections are difficult to diagnose because blood cultures are often negative. Clinically, it is important to recognize the possibility of NTM-PVE in the differential diagnosis of culture-negative patients who develop signs and symptoms of endocarditis, whether they present early or late in onset after the surgical procedure. These patients should be treated with surgical removal of the infected valve, followed by adequate antimicrobial therapy based on the susceptibility of the species isolated from the valve or perivalvular tissue culture. In a significant number of patients, however, an unstable hemodynamic condition ensues, precluding surgical intervention, and therefore leading to a high mortality rate.

Totally biological composite aortic stentless valved conduit for aortic root replacement: 10-year experience

Objectives

To retrospectively analyze the clinical outcome of a totally biological composite stentless aortic valved conduit (No-React^® BioConduit) implanted using the Bentall procedure over ten years in a single centre.

Methods

Between 27/10/99 and 19/01/08, the No-React^® BioConduit composite graft was implanted in 67 patients. Data on these patients were collected from the in-hospital database, from patient notes and from questionnaires. A cohort of patients had 2D-echocardiogram with an average of 4.3 ± 0.45 years post-operatively to evaluate valve function, calcification, and the diameter of the conduit.

Results

Implantation in 67 patients represented a follow-up of 371.3 patient-year. Males were 60% of the operated population, with a mean age of 67.9 ± 1.3 years (range 34.1-83.8 years), 21 of them below the age of 65. After a mean follow-up of 7.1 ± 0.3 years (range of 2.2-10.5 years), more than 50% of the survivors were in NYHA I/II and more than 60% of the survivors were angina-free (CCS 0). The overall 10-year survival following replacement of the aortic valve and root was 51%. During this period, 88% of patients were free from valved-conduit related complications leading to mortality. Post-operative echocardiography studies showed no evidence of stenosis, dilatation, calcification or thrombosis. Importantly, during the 10-year follow-up period no failures of the valved conduit were reported, suggesting that the tissue of the conduit does not structurally change (histology of one explant showed normal cusp and conduit).

Conclusions

The No-React^® BioConduit composite stentless aortic valved conduit provides excellent long-term clinical results for aortic root replacement with few prosthesis-related complications in the first post-operative decade.

Recommendations for the practice of echocardiography in infective endocarditis

Echocardiography plays a key role in the assessment of infective endocarditis (IE). It is useful for the diagnosis of endocarditis, the assessment of the severity of the disease, the prediction of short- and long-term prognosis, the prediction of embolic events, and the follow-up of patients under specific antibiotic therapy. Echocardiography is also useful for the diagnosis and management of the complications of IE, helping the physician in decision-making, particularly when a surgical therapy is considered. Finally, intraoperative echocardiography must be performed in IE to help the surgeon in the assessment and management of patients with IE during surgery. The current 'recommendations for the practice of echocardiography in infective endocarditis' aims to provide both an updated summary concerning the value and limitations of echocardiography in IE, and clear and simple recommendations for the optimal use of both transthoracic and transoesophageal echocardiography in IE.

Diagnostic evaluation of left-sided prosthetic heart valve dysfunction

Prosthetic heart valve (PHV) dysfunction is a rare, but potentially life-threatening, complication. In clinical practice, PHV dysfunction poses a diagnostic dilemma. Echocardiography and fluoroscopy are the imaging techniques of choice and are routinely used in daily practice. However, these techniques sometimes fail to determine the specific cause of PHV dysfunction, which is crucial to the selection of the appropriate treatment strategy. Multidetector-row CT (MDCT) can be of additional value in diagnosing the specific cause of PHV dysfunction and provides valuable complimentary information for surgical planning in case of reoperation. Cardiac magnetic resonance imaging (CMR) has limited value in the evaluation of biological PHV dysfunction. In this Review, we discuss the use of established imaging modalities for the detection of left-sided mechanical and biological PHV dysfunction and discuss the complementary role of MDCT in this context.

The changing face of prosthetic valve endocarditis at a tertiary-care hospital: 1986-2005

INTRODUCTION AND OBJECTIVES

To investigate changes in the clinical characteristics, etiology and prognosis of prosthetic valve endocarditis at a tertiary-care hospital.

METHODS

Retrospective cohort study of all patients diagnosed with prosthetic valve endocarditis using modified Duke criteria between 1986 and 2005. The analysis covered two time periods: January 1986 to December 1995 (P1) and January 1996 to December 2005 (P2).

RESULTS

In total, 133 episodes of endocarditis occurred in 122 patients. Of these, 73 (54.9%) were diagnosed in P1 and 60 (45.1%) in P2, with incidences of 2.19% and 2.18%, respectively. The patients' mean age (SD) was 52.6+/-16.6 years in P1 and 66.2+/-11.5 years in P2 (P=.0001). Clinical characteristics were similar in the two study periods. The increase in Enterococcus infection was remarkable (12.5% in P2 vs. 4.9% in P1; relative risk [RR]=2.5; 95% confidence interval [CI], 0.7-9.6), as was the decrease in viridans group Streptococcus infection (12.5% in P2 vs. 31.1% in P1; RR=0.4; 95% CI, 0.2-0.9). Some 90.4% of patients (63/73) underwent surgery in P1, while 68.3% (41/60) underwent surgery in P2. The difference was significant (RR=0.8; 95% CI, 0.6-0.9). The in-hospital mortality rate was 28.8% in P1 and 30% in P2 (RR=1; 95% CI, 0.6-1.7).

CONCLUSIONS

Changes in the epidemiology and microbiological etiology of prosthetic valve endocarditis were observed over the 20-year study period. Diagnostic and therapeutic approaches also changed, but mortality remained high.

In-hospital prognosis of prosthetic valve endocarditis after urgent surgery

INTRODUCTION AND OBJECTIVES

Prosthetic valve endocarditis is associated with high morbidity and mortality, particularly when urgent surgery is needed. The identification of factors that predict a poor prognosis is the first step in improving outcomes. The study objectives were to characterize patients with prosthetic valve endocarditis who need urgent surgery and to identify factors that predict in-hospital mortality in this high-risk group.

METHODS

From a database of 648 consecutive patients with infective endocarditis diagnosed between 1996 and 2006 at four tertiary-care centers with cardiac surgery facilities, 46 patients with left-sided prosthetic valve endocarditis who needed urgent surgery were identified. A retrospective study was carried out to determine these patients' main characteristics and to identify predictors of in-hospital mortality.

RESULTS

The main indications for urgent surgery were heart failure (57%) and persistent infection (33%). In-hospital mortality was 41%. Factors significantly associated with a poor prognosis were fever at admission, persistent infection, positive blood cultures, persistently positive cultures, and echocardiographic evidence of vegetations (P< .05). No specific microorganism was associated with a poor prognosis.

CONCLUSIONS

Prosthetic valve endocarditis was associated with high mortality when urgent surgery was needed. Although heart failure was the principle reason for urgent surgery, it did not lead to a worse in-hospital prognosis. The presence of vegetations and uncontrolled infection were the main factors associated with higher in-hospital mortality in patients with left-sided infective endocarditis who needed urgent surgery.

Acute infective endocarditis

Acute infective endocarditis is a complex disease with changing epidemiology and a rapidly evolving knowledge base. To consistently achieve optimal outcomes in the management of infective endocarditis, the clinical team must have an understanding of the epidemiology, microbiology, and natural history of infective endocarditis, as well as a grasp of guiding principles of diagnosis and medical and surgical management. The focus of this review is acute infective endocarditis, though many studies of diagnosis and treatment do not differentiate between acute and subacute disease, and indeed many principles of diagnosis and management of infective endocarditis for acute and subacute disease are identical.

Left ventricular outflow tract obstruction by a bioprosthetic mitral valve: diagnosis by cardiac computed tomography

Echocardiography has long been the mainstay of noninvasive cardiac diagnostic imaging; however, newer imaging modalities have proven useful in cases where echocardiography has been nondiagnostic. We present a case of a 42-year-old woman with hypertrophic obstructive cardiomyopathy, who despite septal myectomy and bioprosthetic mitral valve replacement, continued to have persistent symptoms of left ventricular outflow tract obstruction. Transthoracic echocardiographic evaluation did not demonstrate the etiology of the patient's symptoms. The cause of our patient's symptoms was clarified using cardiac computed tomography, which revealed a strut from the bioprosthetic mitral valve protruding into the left ventricular outflow tract. Although this clinical phenomenon has previously been described, we will discuss the role of cardiac imaging with computed tomography in this setting.