Prosthetic heart valves: selection of the optimal prosthesis and long-term management

4D-Flow MRI and Vector Ultrasound in the In-Vitro Evaluation of Surgical Aortic Heart Valves - a Pilot Study

INTRODUCTION

The aim of this study was the initial investigation of 4D-Flow MRI and Vector Ultrasound as novel imaging techniques in the in-vitro analysis of hemodynamics in anatomical models. Specifically, by looking at the hemodynamic performance of state-of-the-art surgical heart valves in a 3D-printed aortic arch.

METHODS

The mock circulatory loop simulated physiological, pulsatile flow. Two mechanical and three biological aortic valves prostheses were compared in a 3D-printed aortic arch. 4D magnetic resonance imaging and vector flow Doppler ultrasound served as imaging methods. Hemodynamic parameters such as wall shear stress, flow velocities and pressure gradients were analyzed.

RESULTS

The flow analysis revealed characteristic flow-patterns in the 3D-printed aortic arch. The blood-flow in the arch presented complex patterns, including the formation of helixes and vortices. Higher proximal peak velocities and lower flow volumes were found for biological valves.

CONCLUSION

The mock circulatory loop in combination with modern radiological imaging provides a sufficient basis for the hemodynamic comparison of aortic valves.

Long-Term Risk of Hospitalization and Death in Patients With Mechanical Prosthetic Heart Valves

Mechanical prosthetic heart valves (MPHVs) are commonly used for valvular heart disease in patients with a long life expectancy. Few longitudinal data on the specific causes of hospitalization in patients with MPHV are available. We investigated the risk of all-cause hospitalization and mortality in patients with MPHV. We performed a prospective, observational, ongoing study including consecutive patients with MPHVs who were referred to the atherothrombosis outpatient clinic of the Policlinico Umberto I of Rome for the vitamin K antagonist management. Study end points were all-cause, cardiovascular hospitalization, and overall mortality. We included 305 patients with MPHV (38.4% women, median age 60.2 years). The site of MPHV was aortic in 53.5%, mitral in 29.5%, and mitroaortic in 17%. During a median follow-up of 57.3 months, 142 hospitalizations occurred (8.16 per 100 person-years). The most common causes of hospitalization were cardiovascular disease (3.62 per 100 person-years), infections, surgery, and bleeding. The predictors of cardiovascular hospitalization were atrial fibrillation (hazard ratio [HR] 1.75, 95% confidence interval [CI] 1.04 to 2.95, p = 0.035), previous stroke/transient ischemic attack (HR 2.96, 95% CI 1.59 to 5.48, p = 0.001), and peripheral artery disease (HR 2.42, 95% CI 1.09 to 5.36, p = 0.030). During a median follow-up of 97.2 months, 61 deaths occurred (2.43 per 100 person-years). Age was directly associated with the risk of death (HR 1.088, 95% CI 1.054 to 1.122, p <0.001), whereas the time in therapeutic range higher than the median was inversely associated (HR 0.436, 95% CI 0.242 to 0.786, p = 0.006). In conclusion, patients with MPHV had a high incidence of hospitalizations, especially cardiovascular-related. The incidence of death is high; however, it may be decreased by maintaining a good quality of anticoagulation.

Efficacy and safety of TAVR versus SAVR in patients with small aortic annuli: A systematic review and meta-analysis

INTRODUCTION

Patients with a small aortic annulus (SAA) undergoing aortic valve replacement are at increased risk of patient-prosthesis mismatch (PPM), which adversely affects outcomes. Transcatheter aortic valve replacement (TAVR) has shown promise in mitigating PPM compared to surgical aortic valve replacement (SAVR).

METHODS

We conducted a systematic review and meta-analysis following PRISMA guidelines to compare clinical outcomes, mortality, and PPM between SAA patients undergoing TAVR and SAVR. Eligible studies were identified through comprehensive literature searches and assessed for quality and relevance.

RESULTS

Nine studies with a total of 2476 patients were included. There was no significant difference in 30-day Mortality between TAVR vs SAVR groups (OR = 0.65, 95% CI [ 0.09-4.61], P = 0.22). There was no difference between both groups regarding myocardial infarction at 30 days (OR = 0.63, 95% CI [0.1-3.89], P = 0.62). TAVR was associated with a significantly lower 30-day major bleeding and 2-year major bleeding, Pooled studies were homogeneous (OR = 0.44, 95% CI [0.31-0.64], P < 0.01, I2 = 0, P = 0.89), (OR = 0.4 ,95% CI [0.21-0.77], P = 0.03, I2 = 0%, P = 0.62) respectively. TAVR was associated with a lower rate of moderate PPM (OR = 0.6, 95% CI [ 0.44-0.84], p value = 0.01, i2 = 0%, p value = 0.44). The overall effect estimate did not favor any of the two groups regarding short-term Mild AR (OR = 5.44, 95% CI [1.02-28.91], P = 0.05) and Moderate/severe AR (OR = 4.08, 95% CI [ 0.79-21.02], P = 0.08, I2 = 0%, P = 0.59).

CONCLUSION

Our findings suggest that both TAVR and SAVR are viable options for treating AS in patients with a small aortic annulus. TAVR offers advantages in reducing PPM and major bleeding, while SAVR performs better in terms of pacemaker implantation. Future studies should focus on comparing newer generation TAVR techniques and devices with SAVR. Consideration of patient characteristics is crucial in selecting the optimal treatment approach for AS.

Hemodynamic Comparison of the On-X and Top Hat Mechanical Aortic Valve Prostheses

BACKGROUND

There are limited data comparing hemodynamic valve function in mechanical aortic valve prostheses. This study compared the hemodynamic function of 2 commonly used mechanical aortic valve (AV) prostheses, the On-X (Artivion) and Top Hat (CarboMedics Inc) valves.

METHODS

This study was a retrospective analysis of 512 patients who underwent AV replacement with the On-X (n = 252; 49%) or Top Hat (n = 260; 51%) mechanical valves between 2011 and 2019. Patients were matched on the basis of selected variables. Echocardiographic data were collected preoperatively and postoperatively over a median follow-up of 1.39 years.

RESULTS

A total of 320 patients were matched, 160 patients in each group. Despite being matched for left ventricular outflow tract diameter, patients in the Top Hat group received a greater prevalence of smaller tissue annulus diameter valves (≤21 mm) (83% vs 38%; P < .001). Patients in the On-X group had longer aortic cross-clamp times (78 minutes vs 64 minutes; P < .001) during isolated aortic valve replacement. Discharge echocardiography showed no difference in the AV area index between both groups (1.00 cm2/m2 vs 1.02 cm2/m2; P = .377). During longer-term echocardiographic follow-up, the AV area index remained stable for both valves within their respective tissue annulus diameter groups (P = .060).

CONCLUSIONS

There was no difference between the 2 valves with respect to the AV area index at discharge, and hemodynamic function was stable during longer-term follow-up. The longer aortic cross-clamp time observed in the On-X group may indicate increased complexity of implantation compared with the Top Hat group.

Calcification of surgical aortic bioprostheses and its impact on clinical outcome

AIMS

Aortic valve calcification (AVC) of surgical valve bioprostheses (BPs) has been poorly explored. We aimed to evaluate in vivo and ex vivo BP AVCs and its prognosis value.

METHODS AND RESULTS

Between 2011 and 2019, AVC was assessed using in vivo computed tomography (CT) in 361 patients who had undergone surgical valve replacement 6.4 ± 4.3 years earlier. Ex vivo CT scans were performed for 37 explanted BPs. The in vivo CT scans were interpretable for 342 patients (19 patients [5.2%] were excluded). These patients were 77.2 ± 9.1 years old, and 64.3% were male. Mean in vivo AVC was 307 ± 500 Agatston units (AU). The AVC was 562 ± 570 AU for the 183 (53.5%) patients with structural valve degeneration (SVD) and 13 ± 43 AU for those without SVD (P < 0.0001). In vivo and ex vivo AVCs were strongly correlated (r = 0.88, P < 0.0001). An in vivo AVC > 100 AU (n = 147, 43%) had a specificity of 96% for diagnosing Stage 2-3 SVD (area under the curve = 0.92). Patients with AVC > 100 AU had a worse outcome compared with those with AVC ≤ 100 AU (n = 195). In multivariable analysis, AVC was a predictor of overall mortality (hazard ratio [HR] and 95% confidence interval = 1.16 [1.04-1.29]; P = 0.006), cardiovascular mortality (HR = 1.22 [1.04-1.43]; P = 0.013), cardiovascular events (HR = 1.28 [1.16-1.41]; P < 0.0001), and re-intervention (HR = 1.15 [1.06-1.25]; P < 0.0001). After adjustment for Stage 2-3 SVD diagnosis, AVC remained a predictor of overall mortality (HR = 1.20 [1.04-1.39]; P = 0.015) and cardiovascular events (HR = 1.25 [1.09-1.43]; P = 0.001).

CONCLUSION

CT scan is a reliable tool to assess BP leaflet calcification. An AVC > 100 AU is tightly associated with SVD and it is a strong predictor of overall mortality and cardiovascular events.

Tissue versus mechanical mitral valve replacement in patients aged 50-70: a propensity-matched analysis

OBJECTIVES

There remains debate over the optimal mitral valve replacement (MVR) option for patients aged 50-70 years. The objective of this study was to retrospectively compare the long-term outcomes of mechanical and bioprosthetic MVR in this patient population.

METHODS

Data from patients undergoing MVR between 2004 and 2018 were retrospectively reviewed. The primary outcome was all-cause mortality. Secondary outcomes included perioperative and late morbidity.

RESULTS

Two hundred and eight-six propensity-matched patients (n = 143 mechanical; n = 143 bioprosthetic) aged 50-70 years were included in the final analysis. Maximum follow-up was 15.8 years. There was no significant difference in all-cause mortality between the groups at 30 days, 1 year, 5 years, 10 years, and at the longest follow-up. Patients who underwent mechanical MVR experienced significantly lower rates of postoperative atrial fibrillation (P = 0.001). There were no significant differences in rates of sepsis, acute kidney injury, superficial and deep sternal wound infection, mediastinal bleeding, and permanent pacemaker implantation. At the longest follow-up, there were no differences in myocardial infarction, stroke, heart failure or overall rehospitalization. At the same time point, there was an increased rate of MVR in patients receiving a bioprosthetic valve (P = 0.015).

CONCLUSIONS

Survival following mechanical and bioprosthetic MVR in patients 50-70 years of age is similar to up to 15 years of follow-up. Bioprosthetic MVR is associated with an increased risk of repeat MVR. Mechanical MVR is not associated with an increased risk of stroke. Valve selection in this patient population requires diligent consideration of structural valve deterioration and subsequent reoperation risk as well as bleeding and thromboembolic risk.

Durability of transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) is now utilised as a less invasive alternative to surgical aortic valve replacement (SAVR) across the whole spectrum of surgical risk. Long-term durability of the bioprosthetic valves has become a key goal of TAVI as this procedure is now considered for younger and lower-risk populations. The purpose of this article is to present a state-of-the-art overview on the definition, aetiology, risk factors, mechanisms, diagnosis, clinical impact, and management of bioprosthetic valve dysfunction (BVD) and failure (BVF) following TAVI with a comparative perspective versus SAVR. Structural valve deterioration (SVD) is the main factor limiting the durability of the bioprosthetic valves used for TAVI or SAVR, but non-structural BVD, such as prosthesis-patient mismatch and paravalvular regurgitation, as well as valve thrombosis or endocarditis may also lead to BVF. The incidence of BVF related to SVD or other causes is low (<5%) at midterm (5- to 8-year) follow-up and compares favourably with that of SAVR. The long-term follow-up data of randomised trials conducted with the first generations of transcatheter heart valves also suggest similar valve durability in TAVI versus SAVR at 10 years, but these trials suffer from major survivorship bias, and the long-term durability of TAVI will need to be confirmed by the analysis of the low-risk TAVI versus SAVR trials at 10 years.

Thrombocytopenia after Aortic Valve Replacement Using Sutureless Valves

Background

Sutureless valves are widely used in aortic valve replacement surgery, with Perceval valves and Intuity valves being particularly prominent. However, concerns have been raised about postoperative thrombocytopenia with Perceval valves (Corcym, UK). We conducted a comparative analysis with the Intuity valve (Edwards Lifesciences, USA), and assessed how thrombocytopenia affected patient and transfusion outcomes.

Methods

Among 595 patients who underwent aortic valve replacement from June 2016 to March 2023, sutureless valves were used in 53 (Perceval: n=23; Intuity: n=30). Platelet counts were monitored during hospitalization and outpatient visits. Daily platelet count changes were compared between groups, and the results from patients who underwent procedures using Carpentier Edwards Perimount Magna valves were used as a reference group.

Results

Compared to the Intuity group, the Perceval group showed a significantly higher amount of platelet transfusion (5.48±1.64 packs vs. 0.60±0.44 packs, p=0.008). During the postoperative period, severe thrombocytopenia (<50,000/μL) was significantly more prevalent in the Perceval group (56.5%, n=13) than in the Intuity group (6.7%, n=2). After initial postoperative depletion, daily platelet counts increased, with significant differences observed in the extent of improvement between the Perceval and Intuity groups (p<0.001). However, there was no significant difference in early mortality or the incidence of neurological complications between the 2 groups.

Conclusion

The severity of postoperative thrombocytopenia differed significantly between the Perceval and Intuity valves. The Perceval group showed a significantly higher prevalence of severe thrombocytopenia and higher platelet transfusion volumes. However, thrombocytopenia gradually recovered during the postoperative period in both groups, and the early outcomes were similar in both groups.

Survival after partial heart transplantation in a piglet model

Partial heart transplantation (PHT) is a novel surgical approach that involves transplantation of only the part of the heart containing a valve. The rationale for this approach is to deliver growing heart valve implants that reduce the need for future re-operations in children. However, prior to clinical application of this approach, it was important to assess it in a preclinical model. To investigate PHT short-term outcomes and safety, we performed PHT in a piglet model. Yorkshire piglets (n = 14) were used for PHT of the pulmonary valve. Donor and recipient pairs were matched based on blood types. The piglets underwent PHT at an average age of 44 days (range 34-53). Post-operatively, the piglets were monitored for a period of two months. Of the 7 recipient piglets, one mortality occurred secondary to anesthesia complications while undergoing a routine echocardiogram on post-operative day 19. All piglets had appropriate weight gain and laboratory findings throughout the post-operative period indicating a general state of good health and rehabilitation after undergoing PHT. We conclude that PHT has good short-term survival in the swine model. PHT appears to be safe for clinical application.

Phage Therapy for Cardiac Implantable Electronic Devices and Vascular Grafts: A Targeted Literature Review

Infections of cardiac implantable electronic devices (CIEDs) and vascular grafts are some of the most dreaded complications of these otherwise life-saving devices. Many of these infections are not responsive to conventional treatment, such as systemic antibiotics and surgical irrigation and debridement. Therefore, innovative strategies to prevent and manage these conditions are warranted. Among these, there is an increasing interest in phages as a therapeutical option. In this review, we aim to collect the available evidence for the clinical application of phage therapy for CIED and vascular graft infections through literature research. We found 17 studies for a total of 34 patients. Most of the indications were left ventricular assist device (LVAD) (n = 20) and vascular graft infections (n = 7). The bacteria most often encountered were Staphylococcus aureus (n = 18) and Pseudomonas aeruginosa (n = 16). Clinical improvements were observed in 21/34 (61.8%) patients, with microbiological eradication in 18/21 (85.7%) of them. In eight cases, an adverse event related to phage therapy was reported. Phage therapy is a promising option for difficult-to-treat CIED and vascular graft infections by means of an individualized approach. Clinical trials and expanded access programs for compassionate use are needed to further unveil the role of phage therapy in clinical application.

Mechanical versus Bioprosthetic Aortic Valve Replacement in Patients Aged 50 to 70 Years

Background

This study compared the outcomes of surgical aortic valve replacement (AVR) in patients aged 50 to 70 years based on the type of prosthetic valve used.

Methods

We compared patients who underwent mechanical AVR to those who underwent bioprosthetic AVR at our institution between January 2000 and March 2019. Competing risk analysis and the inverse probability of treatment weighting (IPTW) method based on propensity score were employed for comparisons.

Results

A total of 1,580 patients (984 patients with mechanical AVR; 596 patients with bioprosthetic AVR) were enrolled. There was no significant difference in early mortality between the mechanical AVR and bioprosthetic AVR groups (0.9% vs. 1.7%, p=0.177). After IPTW adjustment, the risk of all-cause mortality was significantly higher in the bioprosthetic AVR group than in the mechanical AVR group (hazard ratio [HR], 1.39; 95% confidence interval [CI], 1.07-1.80; p=0.014). Competing risk analysis revealed lower risks of stroke (sub-distributional hazard ratio [sHR], 0.44; 95% CI, 0.28-0.67; p<0.001) and anticoagulation- related bleeding (sHR, 0.35; 95% CI, 0.23-0.53; p<0.001) in the bioprosthetic AVR group. Conversely, the risk of aortic valve (AV) reintervention was higher in the bioprosthetic AVR group (sHR, 6.14; 95% CI, 3.17-11.93; p<0.001).

Conclusion

Among patients aged 50 to 70 years who underwent surgical AVR, those receiving mechanical valves showed better survival than those with bioprosthetic valves. The mechanical AVR group exhibited a higher risk of stroke and anticoagulation-related bleeding, while the bioprosthetic AVR group showed a higher risk of AV reintervention.

Revisiting echocardiographic features of prosthetic heart valves: the necessity of correct differentiation of mono-leaflet vs. bileaflet mechanical heart valves in a case report

BACKGROUND

Mechanical heart valve replacement is a standard treatment for severe valvular disorders. The use of mono-leaflet valves has decreased recently. Recognizing the echocardiographic features of mono-leaflet and bileaflet valves is crucial for accurate complication diagnosis and proper management.

CASE PRESENTATION

A 65-year-old female with mono-leaflet mitral and bileaflet tricuspid valves underwent an echocardiographic assessment. This simple educational case provides a unique opportunity to compare the echocardiographic features of these valves within a single patient.

CONCLUSION

There is a crucial need for clinicians, particularly those in training, to differentiate between mono-leaflet and bileaflet mechanical heart valves adeptly. With mono-leaflet valves decreasing in prevalence, proficiency in recognizing the echocardiographic nuances of each type is imperative. Failure to do so may result in misdiagnoses and inappropriate management. This underscores the significance of continuous education and vigilance in echocardiographic assessments to ensure optimal patient care.

Partial heart transplantation: Growing heart valve implants for children

Heart valves serve a vital hemodynamic function to ensure unidirectional blood flow. Additionally, native heart valves serve biological functions such as growth and self-repair. Heart valve implants mimic the hemodynamic function of native heart valves, but are unable to fulfill their biological functions. We developed partial heart transplantation to deliver heart valve implants that fulfill all functions of native heart valves. This is particularly advantageous for children, who require growing heart valve implants. This invited review outlines the past, present and future of partial heart transplantation.

The Heart Team during the Pandemic: A Case Report of Bio-Prosthesis Degeneration Treated with Valve in Valve Implantation

The pandemic changed the type of patients. The concept of "patient at the center" became concrete. The execution of simple consultancy was overcome to create effective collaboration and fruitful exchanges between specialists. The "Heart Team" model is on increasing affirmation. The TEAM-BASED approach in the cardiology field is successfully used in patients suffering from ischemic heart disease and valvulopathies for the choice of possible treatments. Degenerative type Sao is the most frequent valvulopathy among the valvulopathies in Western countries and its incidence is correlated with age. In high-risk patients, percutaneous valve replacement (transcatheter aortic valve implantation) is the most valid therapeutic option. The implantation of biological prostheses raises the problem of both degeneration and dysfunction of the prosthesis itself over time in subjects of advanced age and with comorbidities. In this scenario, valve-in-valve (VinV) is a valid therapeutic alternative in high-risk patients. A clinical case of aortic prosthetic degeneration, as an outcome of endocarditis, treated with VinV is presented. The therapeutic decision was made by an "Electronic Heart Team" which represents a further evolution of the treatment pathways and reduces the distance between the specialists in "Hub" Centers and the "Spoke" center.

Comparison of two self-expanding transcatheter heart valves for degenerated surgical bioprostheses: the AVENGER multicentre registry

BACKGROUND

There is a lack of comparative data on transcatheter aortic valve implantation (TAVI) in degenerated surgical prostheses (valve-in-valve [ViV]).

AIMS

We sought to compare outcomes of using two self-expanding transcatheter heart valve (THV) systems for ViV.

METHODS

In this retrospective multicentre registry, we included consecutive patients undergoing transfemoral ViV using either the ACURATE neo/neo2 (ACURATE group) or the Evolut R/PRO/PRO+ (EVOLUT group). The primary outcome measure was technical success according to Valve Academic Research Consortium (VARC)-3. Secondary outcomes were 30-day all-cause mortality, device success (VARC-3), coronary obstruction (CO) requiring intervention, rates of severe prosthesis-patient mismatch (PPM), and aortic regurgitation (AR) ≥moderate. Comparisons were made after 1:1 propensity score matching.

RESULTS

The study cohort comprised 835 patients from 20 centres (ACURATE n=251; EVOLUT n=584). In the matched cohort (n=468), technical success (ACURATE 92.7% vs EVOLUT 88.9%; p=0.20) and device success (69.7% vs 73.9%; p=0.36) as well as 30-day mortality (2.8% vs 1.6%; p=0.392) were similar between the two groups. The mean gradients and rates of severe PPM, AR ≥moderate, or CO did not differ between the groups. Technical and device success were higher for the ACURATE platform among patients with a true inner diameter (ID) >19 mm, whereas a true ID ≤19 mm was associated with higher device success - but not technical success - among Evolut recipients.

CONCLUSIONS

ViV TAVI using either ACURATE or Evolut THVs showed similar procedural outcomes. However, a true ID >19 mm was associated with higher device success among ACURATE recipients, whereas in patients with a true ID ≤19 mm, device success was higher when using Evolut.

Bioprosthetic versus mechanical valves for mitral valve replacement in patients < 70 years: an updated pairwise meta-analysis

BACKGROUND

The ideal conduit for mitral valve replacement (MVR) remains elusive, particularly among younger patients due to increased life expectancy. We perform a pairwise meta-analysis comparing the use of bioprosthetic valves (BPV) and mechanical mitral valves (MMV) in patients < 70 years old undergoing MVR.

METHODS

We comprehensively searched medical databases to identify studies comparing the use of BPV and MMV in patients < 70 years old undergoing MVR. Pairwise meta-analysis was performed using the Mantel-Haenszel method in R version 4.0.2. Outcomes were pooled using the random effect model as risk ratios (RR) with their 95% confidence intervals (95% CI).

RESULTS

16,879 patients from 15 studies were pooled. Compared to MMV, BPV was associated with significantly higher rates of 30-day mortality (RR 1.53, p = 0.0006) but no difference in 30-day stroke (RR 0.70, p = 0.43). At a weighted mean follow-up duration of 14.1 years, BPV was associated with higher rates of long-term mortality (RR 1.28, p = 0.0054). No difference was seen between the two groups for risk of long-term stroke (RR 0.92, p = 0.67), reoperation(RR 1.72, p = 0.12), or major-bleeding (RR 0.57, p = 0.10) at a weighted mean follow-up duration of 11.7, 11.3, and 11.9 years, respectively.

CONCLUSION

The use of MMV in patients < 70 undergoing MVR is associated with lower rates of 30-day/long-term mortality compared to BPV. No significant differences were observed for risk of 30-day/long-term stroke, long-term reoperation, and long-term major bleeding. These findings support the use of MMV in younger patients, although prospective, randomized trials are still needed.

Revisiting aortic valve prosthesis choice in patients younger than 50 years: 10 years results of the AUTHEARTVISIT study

OBJECTIVES

This population-based cohort study investigated mid-term outcome after surgical aortic valve replacement with a bioprosthetic or mechanical valve prosthesis in patients aged <50 years in a European social welfare state.

METHODS

We analysed patient data from the main social insurance carriers in Austria (2010-2020). Subsequent patient-level record linkage with national health data provided patient characteristics and clinical outcome. Survival, reoperation, myocardial infarction, heart failure, embolic stroke or intracerebral haemorrhage, bleeding other than intracerebral haemorrhage and major adverse cardiac events were evaluated as outcomes.

RESULTS

A total of 991 patients were analysed. Regarding demographics, no major differences between groups were observed. Multivariable Cox regression revealed no significant difference in overall survival (P = 0.352) with a median follow-up time of 6.2 years. Reoperation-free survival was decreased (hazard ratio = 1.560 [95% CI: 1.076-2.262], P = 0.019) and the risk for reoperation was increased (hazard ratio = 2.770 [95% CI: 1.402-5.472], P = 0.003) in patients who received bioprostheses. Estimated probability of death after reoperation was 0.23 (CL: 0.08-0.35) after 2 years and 0.34 (CL: 0.06-0.53) after 10 years over both groups. Regarding further outcomes, no significant differences between the two groups were observed.

CONCLUSIONS

In patients below 50 years of age receiving aortic valve replacement, implantation of bioprostheses when compared to mechanical heart valve prostheses was associated with a significantly higher rate of reoperations and reduced reoperation-free survival. Nevertheless, we could not observe a difference in overall survival. However, long-term follow-up has to evaluate that a significantly lower rate of reoperations may translate in consistently improved long-term survival.

Incidence of Prosthesis-Patient Mismatch in Valve-in-Valve with a Supra-Annular Valve

BACKGROUND

Transcatheter aortic valve replacement (TAVR) for a degenerated surgical bioprosthesis (valve-in-valve [ViV]) has become an established procedure. Elevated gradients and patient-prosthesis mismatch (PPM) have previously been reported in mixed TAVR cohorts. We analyzed our single-center experience using the third-generation self-expanding Medtronic Evolut R prosthesis, with an emphasis on the incidence and outcomes of PPM.

METHODS

This is a retrospective analysis of prospectively collected data from our TAVR database. Intraprocedural and intrahospital outcomes are reported.

RESULTS

Eighty-six patients underwent ViV-TAVR with the Evolut R prosthesis. Mean age was 75.5 ± 9.5 years, 64% were males. The mean log EuroScore was 21.6 ± 15.7%. The mean time between initial surgical valve implantation and ViV-TAVR was 8.8 ± 3.2 years. The mean true internal diameter of the implanted surgical valves was 20.9 ± 2.2 mm. Post-AVR, 60% had no PPM, 34% had moderate PPM, and 6% had severe PPM. After ViV-TAVR, 33% had no PPM, 29% had moderate, and 39% had severe PPM. After implantation, the mean transvalvular gradient was reduced significantly from 36.4 ± 15.2 to 15.5 ± 9.1 mm Hg (p < 0.001). No patient had more than mild aortic regurgitation after ViV-TAVR. No conversion to surgery was necessary. Estimated Kaplan-Meier survival at 1 year for all patients was 87.4%. One-year survival showed no significant difference according to post-ViV PPM groups (p = 0.356).

CONCLUSION

ViV-TAVR using a supra-annular valve resulted in low procedural and in-hospital complication rates. However, moderate or severe PPM was common, with no influence on short-term survival. PPM may not be a suitable factor to predict survival after ViV-TAVR.

Aortic root enlargement in patients undergoing mitral and aortic replacement: early outcomes in a sub-Saharan population

Introduction

Aortic root enlargement (ARE) is often required to avoid patient-prosthesis mismatch (PPM) in young patients undergoing aortic surgery, including those undergoing combined mitral and aortic valve replacement (double valve replacement, DVR). Adding ARE to DVR may increase the operative risk by extending the surgical time. Herein, we review our experience with ARE in patients who underwent DVR.

Materials and methods

The medical records of 69 patients who underwent DVR at our institution between February 2008 and November 2021 were retrospectively reviewed. The patients were divided into two groups according to the ARE procedure (ARE-DVR: 25 patients; DVR: 44 patients). Descriptive and comparative analyses of demographic, clinical, and surgical data were performed.

Results

Among the 69 patients who underwent DVR, 35 were women (sex ratio, 0.97). The mean age at surgery was 26.7  ±  13.9 years (range: 7-62 years). Among the 47 patients aged ≤30 years, 40.4% (19/47) were aged between 10 and 20 years, and 6.3% (3/47) were aged <10 years. Patients in the ARE-DVR group were younger (23.3 ± 12.9 years vs. 28.5 ± 14.2 years, p < 0.05). The New York Heart Association Class ≥III dyspnea was the most common symptom (89.9%), with no differences between the two groups. Of all the patients, 84.1% had sinus rhythm. Rheumatic disease was the most common etiology in the entire cohort (91.3%). The mean aortic annulus diameter was 20.54 mm, with smaller sizes found in the ARE-DVR group (18.00 ± 1.47 mm vs. 22.50 ± 2.35 mm, p < 0.05). The aortic cross-clamping duration was greater in the ARE-DVR group (177.6 ± 37.9 min vs. 148.3 ± 66.3 min, p = 0.047). The operative mortality rate was 5.6% for the entire cohort (ARE-DVR: 8% vs. DVR: 4.5%, p = 0.46). Among the patients who underwent echocardiographic control at follow-up, the mean aortic gradient was 19.6 ± 7.2 mmHg (range: 6.14-33 mmHg), with no differences among the groups.

Conclusion

The association between ARE and DVR did not significantly affect operative mortality. ARE can be safely used whenever indications arise to reduce the occurrence of PPM, especially in young patients with growth potential.

Case Series of Early Structural Valve Deterioration of Trifecta Bioprosthesis - New Zealand Experience

PURPOSE

Structural valve deterioration (SVD) remains a limitation on the use of bioprosthetic valves, with patient and valve-related factors contributing to early SVD. The Trifecta valve has been reported to have excellent hemodynamics but studies have highlighted early failure. We present a review and case series at a New Zealand tertiary hospital defining early SVD as failure within 3 years of implant.

METHODS

A retrospective review from January 2015 to July 2019 included 525 patients undergoing surgical aortic valve replacement with 263 patients receiving an Abbott Trifecta or Trifecta Glide Technology (GT) valve. Our review found an acceptable safety profile for the valve with excellent hemodynamics, with a low mortality, stroke, and permanent pacemaker rate.

RESULTS

Three patients out of 263 were identified from the study period as having early SVD requiring reintervention within 3 years of valve implantation leading to a 1.14% failure rate. One of the valves that had early SVD was a new generation Trifecta GT. An additional four patients were identified to have valves implanted prior to the study period and had valve failure at greater than 3 years post implantation. Five cases had cusp tears as their mechanism of failure, raising concerns about durability.

CONCLUSION

The Trifecta valve has an acceptable safety profile and offers good hemodynamics due to the externally mounted leaflets. However, our experience of early SVD and failure is concerning for valve durability. Further comparison to other bioprosthetic valves and longer term follow-up are required to characterize the mechanism of failures.

Durability of Biological Valves Implanted in Aortic or Mitral Positions: A Nationwide Cohort Study

BACKGROUND

Biologic prostheses are being increasingly used for aortic and mitral valve replacement (AVR and MVR). This study evaluated the long-term durability of bioprosthetic valves in the mitral and aortic positions, as no well-designed population-based studies have addressed this issue before.

METHODS

Using Taiwan's National Health Insurance Research Database, we compared biologic valve durability in the mitral and aortic positions in patients hospitalized between 2001 and 2017, with reoperation as the primary outcome. Both between-subject and within-subject designs were used, and the propensity score matching cohort (1:1 ratio) was created for the former.

RESULTS

We identified a total of 10,308 patients, 5462 of whom received AVR, 3901 received MVR, and 945 received double valve replacement. Both AVR and MVR cohorts had 2259 patients after matching. During a mean follow-up of 4.2 years (range, 1 day to 17.9 years), the reoperation rate in the MVR cohort (3.5%) was higher than that in the AVR cohort (2.6%) (hazard ratio 1.41; 95% CI, 1.01-1.98). A higher risk of all-cause death was observed in the MVR cohort (36.5%) than in the AVR cohort (32.6%) (hazard ratio 1.21; 95% CI, 1.10-1.34). Among patients receiving double valve replacement with the same prosthesis type, valves implanted in the aortic position were considerably less likely to require reimplantation.

CONCLUSIONS

Bioprosthetic valve placement in the aortic position is associated with superior outcomes in terms of durability, long-term mortality, and perioperative morbidity. Developing novel interventions and enhancing valve durability would expand bioprosthesis use for valve replacement.

Case report: Self-expanding transcatheter valve implantation (Acurate Neo 2) in a very small native aortic annulus

Transcatheter aortic valve replacement (TAVR) is a treatment of choice in patients with symptomatic severe aortic valve stenosis (AS) and intermediate-to-high surgical risk. The presence of a small aortic annulus (SAA) has been associated with a higher incidence of prosthesis-patient mismatch (PPM) when surgical aortic valve replacement (sAVR) is performed. TAVR might be a treatment option offering better hemodynamics with a lower incidence of PPM. When a severe AS with a SAA is treated, TAVR-related risk as the coronary obstruction and the annulus rupture, must be also prevented. We present a case of a TAVR in a very small aortic annulus; to our knowledge, this is the smallest native aortic annulus treated percutaneously in a tricuspid stenotic aortic valve with a Self-Expanding Transcatheter Heart Valve (THV) Acurate Neo 2.

Embedding and Backscattered Scanning Electron Microscopy (EM-BSEM) Is Preferential over Immunophenotyping in Relation to Bioprosthetic Heart Valves

Hitherto, calcified aortic valves (AVs) and failing bioprosthetic heart valves (BHVs) have been investigated by similar approaches, mostly limited to various immunostaining techniques. Having employed multiple immunostaining combinations, we demonstrated that AVs retain a well-defined cellular hierarchy even at severe stenosis, whilst BHVs were notable for the stochastic degradation of the extracellular matrix (ECM) and aggressive infiltration by ECM-digesting macrophages. Leukocytes (CD45+) comprised ≤10% cells in the AVs but were the predominant cell lineage in BHVs (≥80% cells). Albeit cells with uncertain immunophenotype were rarely encountered in the AVs (≤5% cells), they were commonly found in BHVs (≥80% cells). Whilst cell conversions in the AVs were limited to the endothelial-to-mesenchymal transition (represented by CD31+α-SMA+ cells) and the formation of endothelial-like (CD31+CD68+) cells at the AV surface, BHVs harboured numerous macrophages with a transitional phenotype, mostly CD45+CD31+, CD45+α-SMA+, and CD68+α-SMA+. In contrast to immunostaining, which was unable to predict cell function in the BHVs, our whole-specimen, nondestructive electron microscopy approach (EM-BSEM) was able to distinguish between quiescent and matrix-degrading macrophages, foam cells, and multinucleated giant cells to conduct the ultrastructural analysis of organelles and the ECM, and to preserve tissue integrity. Hence, we suggest EM-BSEM as a technique of choice for studying the cellular landscape of BHVs.

The role of multidetector CT scan in the management of prosthetic aortic valve thrombosis: A case report

Key Clinical Message

In this case report, the utility of MDCT in elucidating the pathophysiology and etiology of prosthetic aortic valve dysfunction allowed us to distinguish thrombosis from pannus as an etiology of prosthetic valve dysfunction. MDCT also guided the success of therapy.

Abstract

The diagnosis and management of prosthetic aortic valve thrombosis (PAVT) is challenging. The accurate diagnosis of this entity and its prompt management is vital to improving the prognosis of PAVT patients. Multidetector CT plays a central role in this effort. We present a case of PAVT in which the use of MDCT was useful in guiding management.

Bioactive surface coating for preventing mechanical heart valve thrombosis

BACKGROUND

Prosthetic heart valves are the only treatment for most patients with severe valvular heart disease. Mechanical valves, made of metallic components, are the most long-lasting type of replacement valves. However, they are prone to thrombosis and require permanent anticoagulation and monitoring, which leads to higher risk of bleeding and impacts the patient's quality of life.

OBJECTIVES

To develop a bioactive coating for mechanical valves with the aim to prevent thrombosis and improve patient outcomes.

METHODS

We used a catechol-based approach to produce a drug-releasing multilayer coating adherent to mechanical valves. The hemodynamic performance of coated Open Pivot valves was verified in a heart model tester, and coating durability in the long term was assessed in a durability tester producing accelerated cardiac cycles. Coating antithrombotic activity was evaluated in vitro with human plasma or whole blood under static and flow conditions and in vivo after surgical valve implantation in a pig's thoracic aorta.

RESULTS

We developed an antithrombotic coating consisting of ticagrelor- and minocycline-releasing cross-linked nanogels covalently linked to polyethylene glycol. We demonstrated the hydrodynamic performance, durability, and hemocompatibility of coated valves. The coating did not increase the contact phase activation of coagulation, and it prevented plasma protein adsorption, platelet adhesion, and thrombus formation. Implantation of coated valves in nonanticoagulated pigs for 1 month efficiently reduced valve thrombosis compared with noncoated valves.

CONCLUSION

Our coating efficiently inhibited mechanical valve thrombosis, which might solve the issues of anticoagulant use in patients and the number of revision surgeries due to valve thrombosis despite anticoagulation.

Prosthesis-Patient Mismatch and Aortic Root Enlargement: Indications, Techniques and Outcomes

Prosthesis-patient mismatch (PPM) is defined as implanting a prosthetic that is insufficiently sized for the patient receiving it. PPM leads to high residual transvalvular gradients post-aortic valve replacement and consequently results in left ventricular dysfunction, morbidity and mortality in both the short and long term. Younger patients and patients with poor preoperative left ventricular function are more vulnerable to increased mortality secondary to PPM. There is debate over the measurement of valvular effective orifice area (EOA) and variation exists in how manufacturers report the EOA. The most reliable technique is using in vivo echocardiographic measurements to create tables of predicted EOAs for different valve sizes. PPM can be prevented surgically in patients at risk through aortic root enlargement (ARE). Established techniques include the posterior enlargement through Nicks and Manouguian procedures, and aortico-ventriculoplasty with the Konno-Rastan procedure, which allows for a greater enlargement but carries increased surgical risk. A contemporary development is the Yang procedure, which uses a Y-shaped incision created through the non- and left-coronary cusp commissure, undermining the nadirs of the non- and left-coronary cusps. Early results are promising and demonstrate an ability to safely increase the aortic root by up to two to three sizes. Aortic root enlargement thus remains a valuable and safe tool in addressing PPM, and should be considered during surgical planning.

ACC/AHA and ESC/EACTS Guidelines for the Management of Valvular Heart Diseases: JACC Guideline Comparison

Valvular heart disease (VHD) is common and poses important challenges from the standpoints of diagnosis and therapeutic management. Clinical practice guidelines have been developed to help health care professionals to overcome these challenges and provide optimal management to patients with VHD. The American College of Cardiology, in collaboration with the American Heart Association, and the European Society of Cardiology, in collaboration with the European Association for Cardio-Thoracic Surgery, recently updated their guidelines on the management of VHD. Although these 2 sets of guidelines are generally concordant, there are some substantial differences between these guidelines, which may have significant implications for clinical practice. This review prepared on behalf of the EuroValve Consortium describes the consistencies and discrepancies between the guidelines and highlights the gaps in these guidelines and the future research perspectives to fill these gaps.

Advances in 3D Bioprinting: Techniques, Applications, and Future Directions for Cardiac Tissue Engineering

Cardiovascular diseases are the leading cause of morbidity and mortality in the United States. Cardiac tissue engineering is a direction in regenerative medicine that aims to repair various heart defects with the long-term goal of artificially rebuilding a full-scale organ that matches its native structure and function. Three-dimensional (3D) bioprinting offers promising applications through its layer-by-layer biomaterial deposition using different techniques and bio-inks. In this review, we will introduce cardiac tissue engineering, 3D bioprinting processes, bioprinting techniques, bio-ink materials, areas of limitation, and the latest applications of this technology, alongside its future directions for further innovation.

Differential Immune Response to Bioprosthetic Heart Valve Tissues in the α1,3Galactosyltransferase-Knockout Mouse Model

Structural valve deterioration (SVD) of bioprosthetic heart valves (BHVs) has great clinical and economic consequences. Notably, immunity against BHVs plays a major role in SVD, especially when implanted in young and middle-aged patients. However, the complex pathogenesis of SVD remains to be fully characterized, and analyses of commercial BHVs in standardized-preclinical settings are needed for further advancement. Here, we studied the immune response to commercial BHV tissue of bovine, porcine, and equine origin after subcutaneous implantation into adult α1,3-galactosyltransferase-knockout (Gal KO) mice. The levels of serum anti-galactose α1,3-galactose (Gal) and -non-Gal IgM and IgG antibodies were determined up to 2 months post-implantation. Based on histological analyses, all BHV tissues studied triggered distinct infiltrating cellular immune responses that related to tissue degeneration. Increased anti-Gal antibody levels were found in serum after ATS 3f and Freedom/Solo implantation but not for Crown or Hancock II grafts. Overall, there were no correlations between cellular-immunity scores and post-implantation antibodies, suggesting these are independent factors differentially affecting the outcome of distinct commercial BHVs. These findings provide further insights into the understanding of SVD immunopathogenesis and highlight the need to evaluate immune responses as a confounding factor.

Scientific Evolution of Artificial Heart Valves: A Narrative Review

Cardiovascular disorders have always been the top contributors to the number of mortality occurring worldwide. But the last few decades have seen a drop in those numbers as the lives of millions of people have been saved due to ground-breaking advances in both therapeutic and surgical treatment modalities. Achieving this level of scientific glory in cardiology was a challenging feat. The credit goes to the scientists and physicians of the previous century who, despite their time's technological limitations, made discoveries and laid a solid foundation for modern medicine. Valvular complications are a major part of the global burden of cardiac diseases. The ongoing development of heart valve replacements remains a fascinating subject, as it continues to progress. Valve replacements comprise either mechanical heart valves or bioprosthetic heart valves. Both types of valves have their merits and demerits; their usage depends mostly on individual patient requirements. This article aims to review the evolution of the implantation of heart valves, and it is the objective of this article to give credit to scientists and physicians for their contributions. The article highlights the research gaps in finding more durable materials and the scope of further research in creating a heart valve that can be universally used for better patient outcomes.

Pediatric pulmonary valve replacements: Clinical challenges and emerging technologies

Congenital heart diseases (CHDs) frequently impact the right ventricular outflow tract, resulting in a significant incidence of pulmonary valve replacement in the pediatric population. While contemporary pediatric pulmonary valve replacements (PPVRs) allow satisfactory patient survival, their biocompatibility and durability remain suboptimal and repeat operations are commonplace, especially for very young patients. This places enormous physical, financial, and psychological burdens on patients and their parents, highlighting an urgent clinical need for better PPVRs. An important reason for the clinical failure of PPVRs is biofouling, which instigates various adverse biological responses such as thrombosis and infection, promoting research into various antifouling chemistries that may find utility in PPVR materials. Another significant contributor is the inevitability of somatic growth in pediatric patients, causing structural discrepancies between the patient and PPVR, stimulating the development of various growth-accommodating heart valve prototypes. This review offers an interdisciplinary perspective on these challenges by exploring clinical experiences, physiological understandings, and bioengineering technologies that may contribute to device development. It thus aims to provide an insight into the design requirements of next-generation PPVRs to advance clinical outcomes and promote patient quality of life.

Microbial Biofilm: A Review on Formation, Infection, Antibiotic Resistance, Control Measures, and Innovative Treatment

Biofilm is complex and consists of bacterial colonies that reside in an exopolysaccharide matrix that attaches to foreign surfaces in a living organism. Biofilm frequently leads to nosocomial, chronic infections in clinical settings. Since the bacteria in the biofilm have developed antibiotic resistance, using antibiotics alone to treat infections brought on by biofilm is ineffective. This review provides a succinct summary of the theories behind the composition of, formation of, and drug-resistant infections attributed to biofilm and cutting-edge curative approaches to counteract and treat biofilm. The high frequency of medical device-induced infections due to biofilm warrants the application of innovative technologies to manage the complexities presented by biofilm.

Surgical Aortic Valve Replacement in Patients Aged 50 to 70 Years: Mechanical or Bioprosthetic Valve? A Systematic Review

Although transcatheter aortic valve implantation has emerged as a very attractive treatment option for severe aortic valve disease, surgical aortic valve replacement (SAVR) is still considered the standard-of-care, particularly in younger patients. However, selecting the appropriate type of valve prosthesis for this patient population can pose challenges. The aim of this systematic review was to investigate morbidity and mortality in patients aged 50-70 years who have undergone a first-time SAVR, and to define and compare the outcomes of mechanical valve (MV) and biological valve (BV) prosthesis. A systematic search was conducted to investigate the clinical outcomes of MVs and BVs in patients aged 50-70 years following the PRISMA guidelines. A total of 16,111 patients were included in the studies with an average follow-up of 10 years. A total of 16 studies were selected, 12 of which included propensity-score-matching (PMS) analysis and 4 of which obtained results via multivariate analysis. The vast majority (13 studies) showed no greater survival benefit in either MVs and BVs, while three studies showed an advantage of MVs over BVs. Regarding complications, bleeding was the most common adverse event in patients undergoing MV replacement, while for patients receiving BV prosthesis, it was structural valve deterioration and reoperation. Although the data suggest that the BV option could be a safe option in patients younger than 70 years, more studies with contemporary data are needed to draw firm conclusions on the risks and benefits of BV or MV in SAVR. Physicians should individualize the surgical plan based on patient characteristics.

Dialdehyde xanthan gum and curcumin synergistically crosslinked bioprosthetic valve leaflets with anti-thrombotic, anti-inflammatory and anti-calcification properties

Currently commercial glutaraldehyde (GA)-crosslinked bioprosthetic valve leaflets (BVLs) suffer from thromboembolic complications, calcification, and limited durability, which are the major stumbling block to wider clinical application of BVLs. Thus, developing new-style BVLs will be an urgent need to enhance the durability of BVLs and alleviate thromboembolic complications. In this study, a quick and effective collaborative strategy of the double crosslinking agents (oxidized polysaccharide and natural active crosslinking agent) was reported to realize enhanced mechanical, and structural stability, excellent hemocompatibility and anti-calcification properties of BVLs. Dialdehyde xanthan gum (AXG) exhibiting excellent stability to heat, acid-base, salt, and enzymatic hydrolysis was first introduced to crosslink decellularized porcine pericardium (D-PP) and then curcumin with good properties of anti-inflammatory, anti-coagulation, anti-liver fibrosis, and anti-atherosclerosis was used to synergistically crosslink and multi-functionalize D-PP to obtain AXG + Cur-PP. A comprehensive evaluation of structural characterization, hemocompatibility, endothelialization potential, mechanical properties and component stability showed that AXG + Cur-PP exhibited better anti-thrombotic properties and endothelialization potential, milder immune responses, excellent anti-calcification properties and enhanced mechanical properties compared with GA-crosslinked PP. Overall, this cooperative crosslinking strategy provides a novel solution to achieve BVLs with enhanced mechanical properties and excellent anti-coagulation, anti-inflammatory, anti-calcification, and the ability to promote endothelial cell proliferation.

Diagnosis of Left-Sided Mechanical Prosthetic Valve Thrombosis: A Pictorial Review

Although transcatheter valve therapy is rapidly evolving, surgical valve replacement is still required in many patients with severe left-side valve stenosis or regurgitation, the mechanical bi-leaflet heart valve being the standard prosthesis type in younger patients. Moreover, the prevalence of valvular heart disease is steadily increasing, especially in industrialized countries, and the problem of lifelong efficient anticoagulation of these patients remains fundamental, especially in the context where vitamin K antagonists continue to be the current standard of anticoagulation despite a level of oscillating anticoagulation. In this setting, avoiding prosthetic valve thrombosis after surgery is the number one objective for both the patient and the responsible physicians. Although rare, this complication is life threatening, with the sudden onset of acute cardiac failure such as acute pulmonary edema, cardiogenic shock, or sudden cardiac death and inadequate anticoagulation remaining the leading cause of prosthesis thrombosis, along with other risk factors. The availability of multimodal imaging techniques enables and encompasses to a full extent the diagnosis of mechanical valve thrombosis. The gold-standard diagnostic methods are transthoracic and transesophageal echocardiography. Moreover, 3D ultrasound has undoubted value in giving a more accurate description of the thrombus's extension. When transthoracic and transesophageal echocardiography are uncertain, the multidetector computer tomography examination is an important complementary imaging method. Fluoroscopy is also an excellent tool for evaluating the mobility of prosthetic discs. Each method complements the other to differentiate an acute mechanical valve thrombosis from other prosthetic valve pathologies such as pannus formation or infective endocarditis and aids the physician in accurately establishing the treatment method (surgical or pharmaceutical) and its optimal timing. The aim of this pictorial review was to discuss from an imagistic perspective the mechanical prosthetic aortic and mitral valve thrombosis and to provide an overview of the essential role of non-invasive exploration in the treatment of this severe complication.

Biomechanical analysis of novel leaflet geometries for bioprosthetic valves

Objectives

Although bioprosthetic valves have excellent hemodynamic properties and can eliminate the need for lifelong anticoagulation therapy, these devices are associated with high rates of reoperation and limited durability. Although there are many distinct bioprosthesis designs, all bioprosthetic valves have historically featured a trileaflet pattern. This in silico study examines the biomechanical effect of modulating the number of leaflets in a bioprosthetic valve.

Methods

Bioprosthetic valves with 2 to 6 leaflets were designed in Fusion 360 using quadratic spline geometry. Leaflets were modeled with standard mechanical parameters for fixed bovine pericardial tissue. A mesh of each design was structurally evaluated using finite element analysis software Abaqus CAE. Maximum von Mises stresses during valve closure were assessed for each leaflet geometry in both the aortic and mitral position.

Results

Computational analysis demonstrated that increasing the number of leaflets is associated with reduction in leaflet stresses. Compared with the standard trileaflet design, a quadrileaflet pattern reduces leaflet maximum von Mises stresses by 36% in the aortic position and 38% in the mitral position. Maximum stress was inversely proportional to the square of the leaflet quantity. Surface area increased linearly and central leakage increased quadratically with leaflet quantity.

Conclusions

A quadrileaflet pattern was found to reduce leaflet stresses while limiting increases in central leakage and surface area. These findings suggest that modulating the number of leaflets can allow for optimization of the current bioprosthetic valve design, which may translate to more durable valve replacement bioprostheses.

Acquired Von Willebrand Factor Deficiency at Patient-Prosthesis Mismatch after AVR Procedure-A Narrative Review

Acquired von Willebrand factor deficiency has been described in patients with aortic valve stenosis due to high shear forces developed during passage through the narrowed valve orifice, which determines structural changes in this molecule. Similar flow conditions are present in patients with an aortic prosthesis that presents a patient-prosthesis mismatch. Patient-prosthesis mismatch is described by the smaller effective orifice area of the prosthesis than the native valve, which would probably determine similar changes in the molecules of the von Willebrand factor, leading to acquiring von Willebrand deficiency.

MarioHeart: Novel In-Vitro Flow Model for Testing Heart Valve Prostheses and Anticoagulant Therapies

Mechanical heart valve (MHV) prostheses present a risk of thromboembolic complications despite antithrombotic therapy. Further steps in the development of more hemocompatible MHVs and new anticoagulants are impeded due to the lack of adequate in-vitro models. With the development of a novel in-vitro model (MarioHeart), a pulsatile flow similar to the arterial circulation is emulated. The MarioHeart design owns unique features as 1) a single MHV within a torus with low surface/volume ratio, 2) a closed loop system, and 3) a dedicated external control system driving the oscillating rotational motion of the torus. For verification purposes, a blood analog fluid seeded with particles was used to assess fluid velocity and flow rate using a speckle tracking method on high-speed video recordings of the rotating model. The flow rate resembled the physiological flow rate in the aortic root, in both shape and amplitude. Additional in-vitro runs with porcine blood showed thrombi on the MHV associated with the suture ring, which is similar to the in-vivo situation. MarioHeart is a simple design which induces well-defined fluid dynamics resulting in physiologically nonturbulent flow without stasis of the blood. MarioHeart seems suitable for testing the thrombogenicity of MHVs and the potential of new anticoagulants.

Treatment outcome of patients with prosthetic stuck valves at the Cardiac Center of Ethiopia

BACKGROUND

Prosthetic Valve Thrombosis (PVT) is rare but life threatening condition which requires urgent intervention. Patient treatment outcome is not well studied in resource limited settings and the current study aims to explore the treatment outcome of patients with PVT at the Cardiac Center of Ethiopia.

METHODS

The study was conducted at the Cardiac Center of Ethiopia which provides heart valve surgery. All patients who were diagnosed and managed for PVT in the center during the period July 2017 to March 2022 were included in the study. Data were collected through chart abstraction by using a structured questionnaire. Data analysis was done using SPSS version 20.0 for windows software.

RESULT

Eleven patients (13 episodes of stuck valve) with PVT were included in the study and nine of them were female. The median age was 28 years old (IQR 22.5-34.0) with the youngest and oldest patients being 18 and 46 years old respectively. All the patients had bi-leaflet prosthetic mechanical valves (10 at mitral valve, two at aortic and mitral and one at aortic positions). The median duration of valve replacement before having PVT was 36 months (IQR 5-72). All patients reported good adherence to anticoagulant therapy; yet only five had optimal INR value. Nine patients presented with failure symptoms. Eleven patients received thrombolytic therapy and nine of them responded to it. One patient operated for failed thrombolytic therapy. Two patients responded to heparinization and optimization of anticoagulant therapy. Of the ten patients who received streptokinase, two of them developed fever and one patient developed bleeding as a complication of the treatment. All the patients survived hospital discharge.

CONCLUSION

Prosthetic valve thrombosis was accompanied by sub-optimal anticoagulant therapy. Most patients responded to medical therapy alone.

Low-Dose vs Standard Warfarin After Mechanical Mitral Valve Replacement: A Randomized Trial

BACKGROUND

Current guidelines recommend a target international normalized ratio (INR) range of 2.5 to 3.5 in patients with a mechanical mitral prosthesis. The Prospective Randomized On-X Anticoagulation Clinical Trial (PROACT) Mitral randomized controlled noninferiority trial assessed safety and efficacy of warfarin at doses lower than currently recommended in patients with an On-X (Artivion, Inc) mechanical mitral valve.

METHODS

After On-X mechanical mitral valve replacement, followed by at least 3 months of standard anticoagulation, 401 patients at 44 North American centers were randomized to low-dose warfarin (target INR, 2.0-2.5) or standard-dose warfarin (target INR, 2.5-3.5). All patients were prescribed aspirin, 81 mg daily, and encouraged to use home INR testing. The primary end point was the sum of the linearized rates of thromboembolism, valve thrombosis, and bleeding events. The design was based on an expected 7.3% event rate and 1.5% noninferiority margin.

RESULTS

Mean patient follow-up was 4.1 years. Mean INR was 2.47 and 2.92 (P <.001) in the low-dose and standard-dose warfarin groups, respectively. Primary end point rates were 11.9% per patient-year in the low-dose group and 12.0% per patient-year in the standard-dose group (difference, -0.07%; 95% CI, -3.40% to 3.26%). The CI >1.5%, thus noninferiority was not achieved. Rates (percentage per patient-year) of the individual components of the primary end point were 2.3% vs 2.5% for thromboembolism, 0.5% vs 0.5% for valve thrombosis, and 9.13% vs 9.04% for bleeding.

CONCLUSIONS

Compared with standard-dose warfarin, low-dose warfarin did not achieve noninferiority for the composite primary end point. (PROACT Clinicaltrials.gov number, NCT00291525).

Polymeric prosthetic heart valves: A review of current technologies and future directions

Valvular heart disease is an important source of cardiovascular morbidity and mortality. Current prosthetic valve replacement options, such as bioprosthetic and mechanical heart valves are limited by structural valve degeneration requiring reoperation or the need for lifelong anticoagulation. Several new polymer technologies have been developed in recent years in the hope of creating an ideal polymeric heart valve substitute that overcomes these limitations. These compounds and valve devices are in various stages of research and development and have unique strengths and limitations inherent to their properties. This review summarizes the current literature available for the latest polymer heart valve technologies and compares important characteristics necessary for a successful valve replacement therapy, including hydrodynamic performance, thrombogenicity, hemocompatibility, long-term durability, calcification, and transcatheter application. The latter portion of this review summarizes the currently available clinical outcomes data regarding polymeric heart valves and discusses future directions of research.

Mechanical versus Bioprosthetic Aortic Valve Replacement in Middle-Aged Adults: A Systematic Review and Meta-Analysis

BACKGROUND

Mechanical prostheses and bioprosthetic prostheses have their own advantages and disadvantages. Mechanical ones are recommended for younger patients (<50 years old), and bioprosthetic ones are recommended for older patients (>70 years old). There is still debate regarding which kind of prosthesis is better for middle-aged patients (50 to 70 years old) receiving aortic valve replacement (AVR). To solve this problem, we conducted this meta-analysis. Given that only one randomized controlled trial (RCT) study was included, we conducted a subgroup analysis of RCT and propensity score matching (PSM) retrospective studies to reduce the bias.

METHODS

We systematically searched articles related to clinical outcomes of mechanical and bioprosthetic prostheses in middle-aged patients receiving AVR in the PubMed, Cochrane Library, and China National Knowledge Infrastructure (CNKI) databases. The published date was up to 1 October 2022. Studies were excluded if not only middle-aged patients were included, or if they lacked direct comparisons between mechanical and bioprosthetic prostheses.

RESULTS

In total, 22 studies with 32,298 patients were included in the final analysis. The results show that patients aged between 50 and 70 receiving AVR with mechanical prostheses achieved better long-term survival and fewer reoperations and valve-related events but suffered more with bleeding events. No significant difference could be found in terms of early mortality and long-term cardiac death. The same results could be observed in the subgroup analysis of RCT and PSM retrospective studies.

CONCLUSION

Both mechanical and bioprosthetic prostheses are beneficial to middle-aged patients undertaking AVR procedures. However, mechanical prostheses show better clinical outcomes in long-term survival and comorbidities. Individual recommendation is still necessary.

Impact of Aortic Root Enlargement on Patients Undergoing Aortic Valve Replacement

BACKGROUND

Aortic root enlargement (ARE) can be an important adjunct for aortic valve replacement (AVR). This study compared outcomes of AVR with or without ARE.

METHODS

This was an observational study using an institutional database of AVRs from 2010 to 2020 comparing patients who underwent isolated AVR vs AVR with ARE (AVR+ARE). Kaplan-Meier survival estimation and Cox regression were performed.

RESULTS

Of 2371 patients, 2240 (94.5%) underwent isolated AVR and 131 (5.5%) underwent AVR+ARE. Patients who underwent AVR+ARE were more likely to be women and to be younger than those who underwent isolated AVR. Prosthesis size was smaller in patients undergoing AVR+ARE (23 mm [interquartile range {IQR}, 21-25] vs 25 mm [IQR, 23-25], P < .001), but indexed effective orifice area did not differ between the 2 groups. Operative mortality was comparable for AVR (2.3%) and AVR+ARE (3.8%, P = .28). Patients who underwent AVR+ARE had a longer length of stay (7 days [IQR, 6-13] vs 6 days [IQR 5-10], P < .001), were more likely to have acute kidney injury (6.1% vs 2.5%, P = .01), were more likely to require blood product transfusions (40.5% vs 27.6%, P < .001), and were more likely to require prolonged ventilation > 24 hours (16.0% vs 6.8%, P < .001). Rates of stroke, atrial fibrillation, permanent pacemaker, and reoperation were comparable between groups. Kaplan-Meier survival estimates were similar, and on multivariable regression AVR+ARE was not associated with an increased hazard of death as compared with AVR (hazard ratio, 1.09; 95% confidence interval, 0.81-1.46; P = .59).

CONCLUSIONS

ARE can be safely performed with isolated AVR and should be considered for patients with small annuli to avoid prosthesis-patient mismatch.

Cognitive function and delirium following sevoflurane or propofol anesthesia for valve replacement surgery: A multicenter randomized controlled trial

Cognitive dysfunction is a common postoperative neurological complication in patients undergoing valve replacement surgery. This study aimed to compare the effects of sevoflurane versus propofol-based total intravenous anesthesia on the incidence of cognitive dysfunction following valve replacement surgery. This multicenter, randomized, controlled double-blinded study was conducted in three teaching hospitals in China. Patients receiving on-pump valve replacement surgery were enrolled. Stratified block randomization was used to randomly assign patients 1:1 to receive sevoflurane (1.0-1.5 MAC) or propofol (2.0-3.0 mg/kg/h) for anesthesia maintenance. The primary outcome was the incidence of cognitive dysfunction assessed by four cognitive tests before, as well as 7-14 days after surgery. Patients were randomly assigned to receive sevoflurane anesthesia (n = 144) or propofol-based total intravenous anesthesia (n = 145). The incidence of postoperative cognitive dysfunction in the sevoflurane anesthesia group (31.9%) was significantly lower than that in the total intravenous anesthesia group (43.4%; relative risk 0.61, 95% confidence interval [CI]: 0.38-0.97, p = 0.044). There was no difference in the incidence of delirium between patients receiving sevoflurane and total intravenous anesthesia (27.8% [35/144] vs. 25.9% [35/145], 1.10, 95% CI: 0.64 to 1.90, p = 0.736). There was a significant difference in the Katz Index on day 3 after surgery (3 [0.9) vs. 3 (1.0], 0.095, 95% CI: 0.05 to 0.43, p = 0.012). No difference was observed in other outcomes between the two groups. For patients undergoing on-pump valve replacement surgery, sevoflurane anesthesia had a smaller effect on cognitive function and independence in daily life activities compared with propofol anesthesia.

The ratio of measured and reference effective orifice areas for discriminating prosthetic aortic valve obstruction

AIMS

We aimed to evaluate the efficacy of the measured effective orifice area (EOA)/reference EOA ratio in discriminating mechanical prosthetic aortic valve (PAV) obstruction.

METHODS AND RESULTS

This is a retrospective study of 193 mechanical PAV patients with an elevated mean transprosthetic pressure gradient (PG) over 20 mmHg or peak velocity over 3 m/s. Of those, 143 patients were objectively proven PAV obstruction with cardiac computed tomography or surgical inspection. The EOA was measured using the continuity equation, and the reference EOA values were obtained from previous guidelines. The measured/reference EOA ratio was significantly lower in the obstruction group (0.63 ± 0.18 vs. 0.86 ± 0.17; P < 0.001). The EOA ratio added incremental value for discriminating obstruction from the conventional parameters recommended in the guidelines. Receiver operating characteristic curve analysis revealed that the measured/reference EOA ratio discriminated PAV obstruction from those without obstruction [area under the curve (AUC), 0.840; 95% confidence interval, 0.783-0.898; P < 0.001]. A cutoff of 0.71 had 73.4% sensitivity and 82.0% specificity. The novel diagnostic algorithm adding the EOA ratio had similar accuracy to previous guideline algorithms, including reference EOA, and conventional Doppler parameters (AUC, 0.763 vs. 0.731; P = 0.309). In patients with a large PAV (≥23 mm), the novel algorithm had higher accuracy than the previous algorithm (AUC, 0.788 vs. 0.642; P = 0.019).

CONCLUSION

The ratio of measured/reference EOA adds incremental value over conventional Doppler parameters and might be helpful for distinguishing PAV obstruction.

Mock circulatory loop applications for testing cardiovascular assist devices and in vitro studies

The mock circulatory loop (MCL) is an in vitro experimental system that can provide continuous pulsatile flows and simulate different physiological or pathological parameters of the human circulation system. It is of great significance for testing cardiovascular assist device (CAD), which is a type of clinical instrument used to treat cardiovascular disease and alleviate the dilemma of insufficient donor hearts. The MCL installed with different types of CADs can simulate specific conditions of clinical surgery for evaluating the effectiveness and reliability of those CADs under the repeated performance tests and reliability tests. Also, patient-specific cardiovascular models can be employed in the circulation of MCL for targeted pathological study associated with hemodynamics. Therefore, The MCL system has various combinations of different functional units according to its richful applications, which are comprehensively reviewed in the current work. Four types of CADs including prosthetic heart valve (PHV), ventricular assist device (VAD), total artificial heart (TAH) and intra-aortic balloon pump (IABP) applied in MCL experiments are documented and compared in detail. Moreover, MCLs with more complicated structures for achieving advanced functions are further introduced, such as MCL for the pediatric application, MCL with anatomical phantoms and MCL synchronizing multiple circulation systems. By reviewing the constructions and functions of available MCLs, the features of MCLs for different applications are summarized, and directions of developing the MCLs are suggested.

Surgical Valve Choices for Pulmonary Valve Replacement

The range of valve choices available to the cardiac surgeon for placement in the pulmonary position continues to expand. This article will provide a brief compendium of the most clinically relevant among these choices and review the contemporary literature regarding their relative durability as well as risk factors for structural valve deterioration and reintervention. The unique advantages and disadvantages of each of these valve choices will be discussed as they pertain to unique patient-specific factors, including patient size and the anatomy of the right ventricular outflow tract, that inform the choice of one prosthesis over another. Finally, general principles regarding the approach to valve choice, and future directions will be discussed.

Effects of short-term oral anticoagulation following surgical bioprosthetic aortic valve replacement

BACKGROUND

Short-term oral anticoagulation (OAC) is recommended for patients after surgical bioprosthetic aortic valve replacement (bAVR); however, the potential benefits remain controversial. This study evaluated the effects of short-term OAC following bAVR.

METHODS

From 2010 to 2017, total 450 patients who underwent bAVR were enrolled. The outcomes of patients who did (OAC group) and who did not receive OAC (without-OAC group) after bAVR were compared. Propensity-score matching (PSM) was used to adjust for potential confounders, and a 1:1 matched cohort was formed. The main outcomes were all-cause mortality and bioprosthetic valve dysfunction (BVD).

RESULTS

A total of 175 (39%) patients received OAC after bAVR. The median follow-up period was 2.9 years, the median duration of OAC use was 4 months; 162 pairs of patients were identified after the PSM. There was no significant difference in the prevalence of 1-year embolism/ischemic stroke between the OAC and without-OAC group in PSM cohort (0.62% vs. 1.89% for embolism, p = 0.623; 0 vs. 1.23% for ischemic stroke, p = 0.499). The prevalence of 1-year intracranial hemorrhage (ICH) between OAC and without-OAC group was also comparable (0.62% vs. 0.62%, p = 1). The OAC group had a lower all-cause mortality (adjusted hazard ratio (aHR):0.488, 95% confidence interval (CI): 0.259-0.919). There was also a trend for reduced BVD in the OAC group (aHR: 0.661, 95% CI: 0.339-1.290).

CONCLUSION

Our study demonstrated that short-term OAC use after bAVR was associated with lower all-cause mortality. The prevalence of 1-year embolism/ischemic stroke/ICH were comparable despite of OAC use.