Bacterial adherence to graft tissues in static and flow conditions

A high throughput microphysiological model of prosthetic valve endocarditis for investigating factors that influence bacterial adhesion under fluid shear stress

Prosthetic heart valves are associated with almost one quarter of cases of infective endocarditis, a rare but serious condition with a staggering 25 % mortality rate. Without the endothelium of native valves, the risk of infection is exacerbated for implanted devices exposed to blood. There are currently no physiologically relevant in vitro or animal models of prosthetic valve endocarditis (PVE). Of particular importance, Staphylococcus aureus, a common agent of PVE, has demonstrated enhanced binding to blood plasma proteins (e.g., fibrinogen) and exposed matrix under fluid shear stress (FSS). An in vitro platform that mimics the multiple physiological determinants for S. aureus adhesion to prosthetic valve materials would facilitate the discovery of new treatments to minimize PVE. To this end, we developed a first-of-its-kind microphysiological model of PVE to study the effects of several key variables (endothelial cell coverage, fibrinogen deposition, surface treatments, and FSS) on S. aureus adhesion to bioprosthetic material surfaces. Our model demonstrated that viable endothelial monolayers diminished the deposition of fibrinogen and that fibrinogen was required for the subsequent adhesion of S. aureus to the bioprosthetic surface model. Next, we examined factors that affected endothelial cell coverage, such as FSS and glutaraldehyde, a common chemical treatment for bioprosthetic materials. In particular, glutaraldehyde treatment obstructed endothelialization of otherwise biocompatible collagen-coated surfaces, further enabling fibrinogen and S. aureus deposition. In future work, this model could impact multiple research areas, such as screening candidate bioprosthetic valve materials and new surface treatments to prevent PVE and further understanding host-pathogen interactions.

Infective Endocarditis Risk with Melody versus Sapien Valves Following Transcatheter Pulmonary Valve Implantation: A Systematic Review and Meta-Analysis of Prospective Cohort Studies

BACKGROUND

Transcatheter pulmonary valve implantation (TPVI) is an effective non-surgical treatment method for patients with right ventricle outflow tract dysfunction. The Medtronic Melody and the Edwards Sapien are the two valves approved for use in TPVI. Since TPVI patients are typically younger, even a modest annual incidence of infective endocarditis (IE) is significant. Several previous studies have shown a growing risk of IE after TPVI. There is uncertainty regarding the overall incidence of IE and differences in the risk of IE between the valves.

METHODS

A systematic search was conducted in the MEDLINE, EMBASE, PubMed, and Cochrane databases from inception to 1 January 2023 using the search terms 'pulmonary valve implantation', 'TPVI', or 'PPVI'. The primary outcome was the pooled incidence of IE following TPVI in Melody and Sapien valves and the difference in incidence between Sapien and Melody valves. Fixed effect and random effect models were used depending on the valve. Meta-regression with random effects was conducted to test the difference in the incidence of IE between the two valves.

RESULTS

A total of 22 studies (including 10 Melody valve studies, 8 Sapien valve studies, and 4 studies that included both valves (572 patients that used the Sapien valve and 1395 patients that used the Melody valve)) were used for the final analysis. Zero IE incidence following TPVI was reported by eight studies (66.7%) that utilized Sapien valves compared to two studies (14.3%) that utilized Melody valves. The pooled incidence of IE following TPVI with Sapien valves was 2.1% (95% CI: 0.9% to 5.13%) compared to 8.5% (95% CI: 4.8% to 15.2%) following TPVI with Melody valves. Results of meta-regression indicated that the Sapien valve had a 79.6% (95% CI: 24.2% to 94.4%, p = 0.019; R2 = 34.4) lower risk of IE incidence compared to the Melody valve.

CONCLUSIONS

The risk of IE following TPVI differs significantly. A prudent valve choice in favor of Sapien valves to lower the risk of post-TPVI endocarditis may be beneficial.

Infective endocarditis after transcatheter pulmonary valve implantation in patients with congenital heart disease: Distinctive features

The introduction of transcatheter pulmonary valve implantation (TPVI) has greatly benefited the management of right ventricular outflow tract dysfunction. Infective endocarditis (IE) is a feared complication of TPVI that affects valve durability and patient outcomes. Current recommendations provide only limited guidance on the management of IE after TPVI (TPVI-IE). This article, by a group of experts in congenital heart disease in children and adults, interventional cardiology, infectious diseases including IE, and microbiology, provides a comprehensive review of the current evidence on TPVI-IE, including its incidence, risk factors, causative organisms, diagnosis, and treatment. The incidence of TPVI-IE varies from 13-91/1000 person-years for Melody valves to 8-17/1000 person-years for SAPIEN valves. Risk factors include history of IE, DiGeorge syndrome, immunosuppression, male sex, high residual transpulmonary gradient and portal of bacteria entry. Staphylococci and streptococci are the most common culprits, whereas Staphylococcus aureus is associated with the most severe disease. In addition to the modified Duke criteria, a high residual gradient warrants a strong suspicion. Imaging studies are helpful for the diagnosis. Intravenous antibiotics guided by blood culture results are the mainstay of treatment. Invasive re-intervention may be required. TPVI-IE in patients with congenital heart disease exhibits several distinctive features. Whether specific valve types are associated with a higher risk of TPVI-IE requires further investigation. Patient and parent education regarding IE prevention may have a role to play and should be offered to all patients.

Current development of bovine jugular vein conduit for right ventricular outflow tract reconstruction

Right ventricular outflow tract (RVOT) reconstruction is a common surgical method to treat congenital cardiac lesions, and bovine jugular vein conduit (BJVC) has become a prevalent candidate of prosthetic material for this procedure since 1999. Although many clinical studies have shown encouraging results on BJVCs, complications such as stenosis, aneurysmal dilatation, valve insufficiency, and infective endocarditis revealed in other clinical outcomes still remain problematic. This review describes the underlying mechanisms causing respective complications, and summarizes the current technological development that may address those causative factors. Novel crosslinking agents, decellularization techniques, conduit coatings, and physical reinforcement materials have improved the performances of BJVCs. The authors expect that the breakthroughs in the clinical application of BJVC may come from new genetic research findings and advanced characterization apparatuses and bioreactors, and are optimistic that the BJVC will in the future provide sophisticated therapies for next-generation RVOT reconstruction.

Nationwide Registry-Based Analysis of Infective Endocarditis Risk After Pulmonary Valve Replacement

Background Infective endocarditis (IE) after pulmonary valve replacements in congenital heart disease is a significant concern. This study aimed to identify specific long-term risk factors for IE after percutaneous pulmonary valve implantation or surgical pulmonary valve replacement. Methods and Results All patients with congenital heart disease from the National Register for Congenital Heart Defects with at least 1 pulmonary valve replacement before January 2018 were included. A total of 1170 patients (56.3% men, median age at study inclusion 12 [interquartile range {Q1-Q3} 5-20 years]) received 1598 pulmonary valve replacements. IE occurred in 4.8% of patients during a follow-up of total 9397 patient-years (median 10 [Q1-Q3, 6-10] years per patient). After homograft implantation 7 of 558 (1.3%) patients developed IE, after heterograft implantation 31 of 723 (4.3%) patients, and after Melody valve implantation 18 of 241 (7.5%) patients. Edwards Sapien and mechanical valves were used less frequently and remained without IE. The incidence of IE in heterografts excluding Contegra valves was 7 of 278 (2.5%), whereas the incidence of IE in Contegra valves was 24 of 445 (5.4%). The risk of IE was not increased compared with homografts if Contegra valves were excluded from the heterografts (hazard ratio [HR], 2.60; P=0.075). The risk of IE was increased for bovine jugular vein valves, Contegra valves (HR, 6.72; P<0.001), and Melody valves (HR, 5.49; P<0.001), but did not differ between Melody valves and Contegra valves (HR, 1.01; P=0.978). Conclusions Bovine jugular vein valves have the highest risk of IE, irrespective of the mode of deployment, either surgical or percutaneous.

Comparison of homografts and bovine jugular vein conduits in the pulmonary position in patients <20 years of age

OBJECTIVE

To compare the performance of homografts and bovine jugular vein (BJV) conduits in the pulmonary position.

METHODS

All patients with congenital heart disease up to age 20 years who underwent pulmonary valve replacement with homografts or BJV at 3 centers in Australia were evaluated. There were 674 conduits, with 305 (45%) pulmonary homografts (PHs), 303 (45%) BJV conduits, and 66 (10%) aortic homografts (AHs). Endpoints were freedom from reintervention, structural valve degeneration (SVD), and infective endocarditis (IE). Propensity score matching was used to balance the comparison of PH and BJV conduits.

RESULTS

The median follow-up was 6.4 years (interquartile range, IQR, 3.1-10.7 years). Freedom from reintervention at 5 and 10 years was 92% and 80%, respectively, for PH, 74% and 37% for BJV, and 75% and 47% for AH. BJV conduits had a higher risk of reintervention (P < .001) and SVD (P < .001) compared with PHs. These findings were confirmed with propensity score matching valid for conduit size >15 mm. AHs >15 mm had a higher risk of reintervention (P < .001) and SVD (P < .001) compared with PHs >15 mm. The performance of AHs and BJV conduits was similar across all sizes (reintervention, P = .94; SVD, P = .72). The incidence of IE was 1% for PH, 10% for BJV, and 1.5% for AH.

CONCLUSIONS

In patients age <20 years with a conduit >15 mm, PHs outperformed BJV conduits and AHs in the pulmonary position. The performance of AH and BJV was comparable. Small conduits (≤15 mm) had similar performance across all conduit types.

Mid-term outcomes of Contegra implantation for the reconstruction of the right ventricular outflow tract to proximal branch pulmonary arteries: Japan multicentre study

OBJECTIVES

To reveal the mid-term outcomes of Contegra implantation for the reconstruction of the right ventricular outflow tract to proximal branch pulmonary arteries in a multicentre study.

METHODS

Between April 2013 and December 2019, 178 Contegra conduits were implanted at 5 Japanese institutes. The median age and body weight at operation were 16 months (25th-75th percentile: 8-32) and 8.3 kg (6.4-10.6). Sixteen patients were neonates (9.0%). Selected conduit sizes were 12 mm in 28 patients (15.7%), 14 mm in 67 patients (37.6%), 16 mm in 66 patients (37.1%), 18 mm in 5 patients (2.8%) and <12 mm in 12 patients (6.7%). Fifty-six grafts (31.4%) were ring supported. Proximal branch pulmonary arteries were concomitantly augmented in 85 patients (47.5%). Follow-up was completed in all patients and the median follow-up period was 3.1 years (1.3-5.1).

RESULTS

The overall, conduit explantation-free and conduit infection-free survival rates at 5 years were 91.3%, 71.0% and 83.7%, respectively. Infection (P = 0.009) and common arterial trunk (P = 0.024) were risk factors for explantation. Conduit durability was shorter in smaller one (P < 0.001). Catheter interventions (for conduit to proximal branch pulmonary artery)-free survival rates at 5 years was 52.9%; however, need for catheter interventions was not a risk factor for conduit explantation.

CONCLUSIONS

Mid-term outcomes of reconstruction of the right ventricular outflow tract to the proximal branch pulmonary arteries with Contegra were acceptable. The need for explantation over time was higher in smaller conduits. Conduit infection was a strong risk factor for conduit explantation. Frequently and repeated catheter interventions effectively extended the conduit durability.

Staphylococcus aureus adheres avidly to decellularised cardiac homograft tissue in vitro in the fibrinogen-dependent manner

OBJECTIVE

Infective endocarditis remains a severe complication associated with a high morbidity and mortality in patients after heart valve replacement. Exploration of the pathogenesis is of high demand and we, therefore, present a competent model that allows studying bacterial adherence and the role of plasma fibrinogen in this process using a new in-house designed low-volume flow chamber. Three cardiac graft tissues used for pulmonary valve replacement have been tested under shear conditions to investigate the impact of surface composition on the adhesion events.

METHODS

Tissue pieces of cryopreserved homograft (non-decellularised), decellularised homograft and bovine pericardium patch were investigated for fibrinogen binding. Adherence of Staphylococcus aureus to these graft tissues was studied quantitatively under flow conditions in our newly fabricated chamber based on a parallel plates' modality. The method of counting colony-forming units was reliable and reproducible to assess the propensity of different graft materials for bacterial attachment under shear.

RESULTS

Bacterial perfusions over all plasma-precoated tissues identified cryopreserved homograft with the lowest affinity for S. aureus compared to decellularised homograft presenting a significantly higher bacterial adhesion (p < 0.05), which was linked to a more avid fibrinogen binding (p < 0.01). Bovine pericardial patch, as a reference tissue in this study, was confirmed to be the most susceptible tissue graft for the bacterial adhesion, which was in line with our previous work.

CONCLUSION

The two studied homograft tissues showed different levels of bacterial attachment, which might be postulated by the involvement of fibrinogen in the adhesion mechanism(s) shown previously for bovine tissues.

Infective endocarditis in patients after percutaneous pulmonary valve implantation with the stent-mounted bovine jugular vein valve: Clinical experience and evaluation of the modified Duke criteria

AIMS

Percutaneous pulmonary valve implantation (PPVI) has proven good hemodynamic results. As infective endocarditis (IE) remains a potential complication with limited available clinical data, we reviewed our patient records to improve future strategies of IE prevention, diagnosis and treatment.

METHODS

Medical records of all patients diagnosed with Melody® valve IE according to the modified Duke criteria were retrospectively analyzed in three Belgian tertiary centers.

RESULTS

23 IE episodes in 22 out of 240 patients were identified (incidence 2.4% / patient year) with a clear male predominance (86%). Median age at IE was 17.9 years (range 8.2-45.9 years) and median time from PPVI to IE was 2.4 years (range 0.7-8 years). Streptococcal species caused 10 infections (43%), followed by Staphylococcus aureus (n = 5, 22%). In 13/23 IE episodes a possible entry-point was identified (57%). IE was classified as definite in 15 (65%) and as possible in 8 (35%) cases due to limitations of imaging. Echocardiography visualized vegetations in only 10 patients. PET-CT showed positive FDG signals in 5/7 patients (71%) and intracardiac echocardiography a vegetation in 1/1 patient (100%). Eleven cases (48%) had a hemodynamically relevant pulmonary stenosis at IE presentation. Nine early and 6 late percutaneous or surgical re-interventions were performed. No IE related deaths occurred.

CONCLUSIONS

IE after Melody® valve PPVI is associated with a relevant need of re-interventions. Communication to patients and physicians about risk factors is essential in prevention. The modified Duke criteria underperformed in diagnosing definite IE, but inclusion of new imaging modalities might improve diagnostic performance.

Experience and Outcomes of Surgically Implanted Melody Valve in the Pulmonary Position

BACKGROUND

Multiple congenital cardiac malformations require pulmonary valve replacement and/or right ventricular outflow (RVOT) reconstruction. Pulmonary valve replacement remains challenging in children owing to the limited growth potential of prosthetic valves. We evaluated outcomes in patients undergoing surgical implantation of a Melody valve in the RVOT.

METHODS

Data were retrospectively collected for 23 patients undergoing surgical Melody valve implantation at Boston Children's Hospital between 2009 and 2019. We assessed postoperative valve function, reintervention rates, and mortality.

RESULTS

Median age was 1.7 years (range, 2 months to 6 years); 12 patients were aged greater than 2 years (52%). Diagnosis was tetralogy of Fallot in 15 patients (65%); 15 had a prior RVOT operation (65%). The Melody valve was dilated before surgery to a median diameter of 14 mm (range, 10-20 mm). No patients had acute pulmonary regurgitation. One required transcatheter RVOT reintervention before discharge. Median follow-up was 3.7 years (range, 0.02-8.7 years) with moderate or greater pulmonary regurgitation in 2 patients. Catheter-based interventions (mean, 0.83 ± 1.07/patient) occurred at a median of 1 year (range, 16 days to 5.4 years) and included valve expansion for somatic growth (n = 10) and subsequent valve-in-valve replacement (n = 3). Three patients (13%) required surgical valve explant or replacement at a median of 1.0 year (range, 0.6-3.7 years) for Melody-specific indications. One-, 3-, and 5-year freedom from Melody-driven reoperation was 90%, 90%, and 83%, respectively.

CONCLUSIONS

The Melody valve can be surgically implanted in the RVOT of young patients with acceptable early results. These valves can be successfully dilated through transcatheter reintervention to accommodate growth.

Antiplatelet therapy abrogates platelet-assisted Staphylococcus aureus infectivity of biological heart valve conduits

OBJECTIVE

Although recent advances in pulmonary valve replacement have enabled excellent hemodynamics, infective endocarditis remains a serious complication, particularly for implanted bovine jugular vein (BJV) conduits.

METHODS

We investigated contributions by platelets and plasma fibrinogen to endocarditis initiation on various grafts used for valve replacement. Thus, adherence of Staphylococcus aureus and platelets to 5 graft tissues was studied quantitatively in perfusion chambers, assisted by microscopic analysis. We also evaluated standard antiplatelet therapy to prevent onset of S aureus endocarditis.

RESULTS

Of all tissues, bovine pericardium (BP) showed the greatest fibrinogen binding. Perfusion of all plasma-precoated tissues identified BP and BJV_wall with the greatest affinity for S aureus. Perfusions of anticoagulated human blood over all tissues also triggered more platelet adhesion to BP and BJV_wall as single platelets. Several controls confirmed that both S aureus and platelets were recruited on immobilized fibrinogen. In addition, perfusions (and controls) over plasma-coated tissues with whole blood, spiked with S aureus, revealed that bacteria exclusively bound to adhered platelets. Both the platelet adhesion and platelet-mediated S aureus recruitment required platelet α_IIbβ₃ and coated or soluble fibrinogen, respectively, interactions abrogated by the α_IIbβ₃-antagonist eptifibatide. Also, standard antiplatelet therapy (aspirin/ticagrelor) reduced the adherence of S aureus in blood to BJV 3-fold.

CONCLUSIONS

Binding of plasma fibrinogen to especially BJV grafts enables adhesion of single platelets via α_IIbβ₃. S aureus then attaches from blood to (activated) bound platelet α_IIbβ₃ via plasma fibrinogen. Dual antiplatelet therapy appears a realistic approach to prevent endocarditis and its associated mortality.

3-Year Outcomes of the Edwards SAPIEN Transcatheter Heart Valve for Conduit Failure in the Pulmonary Position From the COMPASSION Multicenter Clinical Trial

OBJECTIVES

This study provides the 3-year follow-up results of the COMPASSION (Congenital Multicenter Trial of Pulmonic Valve Regurgitation Studying the SAPIEN Transcatheter Heart Valve) trial. Patients with moderate to severe pulmonary regurgitation and/or right ventricular outflow tract conduit obstruction were implanted with the SAPIEN transcatheter heart valve (THV).

BACKGROUND

Early safety and efficacy of the Edwards SAPIEN THV in the pulmonary position have been established through a multicenter clinical trial.

METHODS

Eligible patients were included if body weight was >35 kg and in situ conduit diameter was ≥16 and ≤24 mm. Adverse events were adjudicated by an independent clinical events committee. Three-year clinical and echocardiographic outcomes were evaluated in these patients.

RESULTS

Fifty-seven of the 63 eligible patients were accounted for at the 3-year follow-up visit from a total of 69 implantations in 81 enrolled patients. THV implantation was indicated for pulmonary stenosis (7.6%), regurgitation (12.7%), or both (79.7%). Twenty-two patients (27.8%) underwent implantation of 26-mm valves, and 47 patients received 23-mm valves. Functional improvement in New York Heart Association functional class was observed in 93.5% of patients. Mean peak conduit gradient decreased from 37.5 ± 25.4 to 17.8 ± 12.4 mm Hg (p < 0.001), and mean right ventricular systolic pressure decreased from 59.6 ± 17.7 to 42.9 ± 13.4 mm Hg (p < 0.001). Pulmonary regurgitation was mild or less in 91.1% of patients. Freedom from all-cause mortality at 3 years was 98.4%. Freedom from reintervention was 93.7% and from endocarditis was 97.1% at 3 years. There were no observed stent fractures.

CONCLUSIONS

Transcatheter pulmonary valve replacement using the Edwards SAPIEN THV demonstrates excellent valve function and clinical outcomes at 3-year follow-up.

Endocarditis After Transcatheter Pulmonary Valve Replacement

BACKGROUND

Endocarditis has emerged as one of the most concerning adverse outcomes in patients with congenital anomalies involving the right ventricular outflow tract (RVOT) and prosthetic valves.

OBJECTIVES

The aim of this study was to evaluate rates and potential risk factors for endocarditis after transcatheter pulmonary valve replacement in the prospective Melody valve trials.

METHODS

All patients in whom a transcatheter pulmonary valve (TPV) was implanted in the RVOT as part of 3 prospective multicenter studies comprised the analytic cohort. The diagnosis of endocarditis and involvement of the TPV were determined by the implanting investigator.

RESULTS

A total of 309 patients underwent transcatheter pulmonary valve replacement (TPVR) and were discharged with a valve in place. The median follow-up duration was 5.1 years, and total observation until study exit was 1,660.3 patient-years. Endocarditis was diagnosed in 46 patients (median 3.1 years after TPVR), and a total of 35 patients were reported to have TPV-related endocarditis (34 at the initial diagnosis, 1 with a second episode). The annualized incidence rate of endocarditis was 3.1% per patient-year and of TPV-related endocarditis was 2.4% per patient-year. At 5 years post-TPVR, freedom from a diagnosis of endocarditis was 89% and freedom from TPV-related endocarditis was 92%. By multivariable analysis, age ≤12 years at implant (hazard ratio: 2.3; 95% confidence interval: 1.2 to 4.4; p = 0.011) and immediate post-implant peak gradient ≥15 mm Hg (2.7; 95% confidence interval: 1.4 to 4.9; p = 0.002) were associated with development of endocarditis and with development of TPV-related endocarditis (age ≤12 years: 2.8; 95% confidence interval: 1.3 to 5.7; p = 0.006; gradient ≥15 mm Hg: 2.6; 95% confidence interval: 1.3 to 5.2; p = 0.008).

CONCLUSIONS

Endocarditis is an important adverse outcome following TVPR in children and adults with post-operative congenital heart disease involving the RVOT. Ongoing efforts to understand, prevent, and optimize management of this complication are paramount in making the best use of TPV therapy. (Melody Transcatheter Pulmonary Valve [TPV] Study: Post Approval Study of the Original Investigational Device Exemption [IDE] Cohort; NCT00740870; Melody Transcatheter Pulmonary Valve Post-Approval Study; NCT01186692; and Melody Transcatheter Pulmonary Valve [TPV] Post-Market Surveillance Study; NCT00688571).

A microscale, full-thickness, human skin on a chip assay simulating neutrophil responses to skin infection and antibiotic treatments

Human skin models are essential for understanding dermatological diseases and testing new treatment strategies. The use of skin biopsies ex vivo is the most accurate model. However, their use is expensive and exposes the donor to pain and scarring. While bioengineered skin samples provide a cheaper alternative, they have limitations due to their simple structure and functionality compared to human skin. Here, we present a skin-on-a-chip device designed to study neutrophil responses to Staphylococcus aureus skin infections. We integrate human skin microcolumns, which have a cross-section that is ∼100 times smaller than traditional skin biopsies, are full-thickness, and are collected using minimally invasive skin sampling techniques. We use human neutrophils directly from one drop of blood, without the need for blood separation. Using the skin-on-a-chip device with skin and blood samples from healthy donors, we show that the neutrophil responses correlate with the bacteria-load in the skin. A pre-incubation step increases the number of migrating neutrophils in response to a low concentration of bacteria. Antibiotic treatment of S. aureus-infected skin samples reduces the number of neutrophils migrating towards the skin. Overall, we validate a skin on a chip model that enables the study of neutrophil migration to the skin in the presence of microbes and following the administration of antibiotics, two situations relevant to clinical cases of human skin and soft tissue infections.

Outcomes of Prosthetic Valved Conduits for Right Ventricular Outflow Tract Reconstruction

There are limited data regarding the implantation of prosthetic valved conduits for right outflow tract reconstruction in pediatric patients in China. A retrospective review of 128 patients undergoing conduits implantation with a median follow-up of 33.3 months (range, 3.3 months to 10.1 years) was performed between 2009 and 2018. Multivariate Cox regression model was used to analyze the risk factors for mortality, reintervention and endocarditis. Freedom from reintervention and endocarditis were plotted using the Kaplan-Meier curve. Hospital mortality was 7.8%, and the late mortality was 3.1%. Patient survival at 1, 5 and 10 years was 92.2%, 87.1% and 84.3%, respectively. Freedom from reintervention at 1 and 5 years was 94.1% and 60.9%. Small size conduit (p = 0.019) and previous palliation (p < 0.001) were predictive of reintervention. Ten conduits developed endocarditis at a median of 4.8 years after implantation. Freedom from endocarditis at 1, 5 and 10 years was 99.1%, 93.0% and 58.0%, respectively. Diffuse stenosis of the conduit (p = 0.003) was an independent risk factor for late endocarditis. Both bovine jugular venous conduits and bovine pericardial prosthetic conduits are associated with acceptable outcomes. Reintervention remains high in patients who have smaller size conduit and undergo previous palliation. It is plausible that the suboptimal flow may be one of major mechanisms involved in the development of late endocarditis.

Pulmonary Regurgitation- Is the Future Percutaneous or Surgical?

For decades, surgical replacement of the pulmonary valve has been seen as the gold-standard technique. Until the advent of Medtronic's Melody valve, it was the only option. Whilst radical changes in surgical techniques have not been forthcoming, rapid and substantial developments in the techniques and available technology for percutaneous valves now cause us to ask if the gold-standard moniker now belongs in the cath lab. This manuscript explores the recent history and future of a revolution in this large area of congenital cardiac practice.