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

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.

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.

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.

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.

Proteolytic Degradation Is a Major Contributor to Bioprosthetic Heart Valve Failure

Background Whereas the risk factors for structural valve degeneration (SVD) of glutaraldehyde-treated bioprosthetic heart valves (BHVs) are well studied, those responsible for the failure of BHVs fixed with alternative next-generation chemicals remain largely unknown. This study aimed to investigate the reasons behind the development of SVD in ethylene glycol diglycidyl ether-treated BHVs. Methods and Results Ten ethylene glycol diglycidyl ether-treated BHVs excised because of SVD, and 5 calcified aortic valves (AVs) replaced with BHVs because of calcific AV disease were collected and their proteomic profile was deciphered. Then, BHVs and AVs were interrogated for immune cell infiltration, microbial contamination, distribution of matrix-degrading enzymes and their tissue inhibitors, lipid deposition, and calcification. In contrast with dysfunctional AVs, failing BHVs suffered from complement-driven neutrophil invasion, excessive proteolysis, unwanted coagulation, and lipid deposition. Neutrophil infiltration was triggered by an asymptomatic bacterial colonization of the prosthetic tissue. Neutrophil elastase, myeloblastin/proteinase 3, cathepsin G, and matrix metalloproteinases (MMPs; neutrophil-derived MMP-8 and plasma-derived MMP-9), were significantly overexpressed, while tissue inhibitors of metalloproteinases 1/2 were downregulated in the BHVs as compared with AVs, together indicative of unbalanced proteolysis in the failing BHVs. As opposed to other proteases, MMP-9 was mostly expressed in the disorganized prosthetic extracellular matrix, suggesting plasma-derived proteases as the primary culprit of SVD in ethylene glycol diglycidyl ether-treated BHVs. Hence, hemodynamic stress and progressive accumulation of proteases led to the extracellular matrix degeneration and dystrophic calcification, ultimately resulting in SVD. Conclusions Neutrophil- and plasma-derived proteases are responsible for the loss of BHV mechanical competence and need to be thwarted to prevent SVD.

Extent of Left Ventricular Mass Regression and Impact of Global Left Ventricular Afterload on Cardiac Events and Mortality after Aortic Valve Replacement

Patient-prosthesis mismatch (PPM) causes a high transvalvular pressure gradient and residual left ventricular (LV) hypertrophy, consequently influencing long-term results. This study aimed to find the relationships between hemodynamic parameters and LV mass regression and determine the risk predictors of major adverse cardiovascular and cerebral events (MACCE) after aortic valve replacement (AVR) for aortic stenosis. Methods and Results: Preoperative and postoperative Doppler echocardiography data were evaluated for 120 patients after AVR. The patients' mean age was 67.7 years; 55% of the patients were male. Forty-four (37%) patients suffered from MACCE during a mean follow-up period of 3.6 ± 2 years. The following hemodynamic parameters at follow-up were associated with lower relative indexed LV mass (LVMI) regression: lower postoperative indexed effective orifice area, greater mean transvalvular pressure gradient (MPG), greater stroke work loss (SWL), and concentric or eccentric LV remodeling mode. The following hemodynamic parameters at follow-up were associated with a higher risk of MACCE: higher valvuloarterial impedance (Z_VA), greater SWL, greater MPG, greater relative wall thickness, greater LVMI, and hypertrophic LV remodeling mode. Lower relative LVMI regression was associated with a higher risk of MACCE (hazard ratio, 1.01: 95% confidence interval, 1.003-1.03). The corresponding cutoff of relative LVMI regression was -14%. Conclusions: Changes in hemodynamic parameters were independently associated with relative LVMI regression. Impaired reverse remodeling and persistent residual LV hypertrophy were independent risk predictors of MACCE. An LVMI regression lower than 14% indicated higher MACCE. A postoperative Z_VA greater than 3.5 mmHg/mL/m² was an independent risk predictor of cardiac events and mortality after AVR. Preventive strategies should be used at the time of the operation to avoid PPM.

Review of bioprosthetic structural valve deterioration: Patient or valve?

BACKGROUND

With guidelines progressively recommending bioprosthetic aortic valves in younger patients, a greater emphasis is placed on structural valve deterioration (SVD) as an important clinical endpoint for both transcatheter and surgically implanted valves. However, SVD of bioprosthetic valves is a complex entity with varying definitions in the literature and a multifaceted pathogenesis.

AIM

This review first aims to establish the most updated definitions of SVD as per the literature. We then explore the patient- and valve-related factors that play the greatest roles in facilitating early SVD.

METHODS

A PubMed literature review was conducted to identify the relevant research in this field within the past two decades.

CONCLUSION

Increasing rates of obesity and metabolic syndrome pose a significant risk to the longevity of bioprosthetic valves. Additionally, externally mounted valves have proven to sacrifice durability for superior haemodynamics. Bioprosthetic SVD continues to be a multifactorial issue that will require various patient- and valve-related factors to be addressed.

Clinical Features and Survival Analysis of Patients after Mechanical Heart Valve Replacement, with an Emphasis on Prosthetic Valve Thrombosis

BACKGROUND

Valvular heart diseases are highly prevalent in the world, and surgical valve replacement has improved patients' survival.

OBJECTIVES

To describe clinical and laboratory data of patients undergoing mechanical valve replacement, and to determine the incidence of prosthetic valve thrombosis (PVT).

METHODS

Retrospective cohort study with a follow-up of up to nine years. The study variables were collected from conventional and electronic medical charts. Statistical calculations were performed using the Jamovi software version 1.2.2.; a p<0.05 was considered statistically significant. Kaplan Meier curves were constructed, and Cox regression analysis was performed for analysis of factors related to mortality.

RESULTS

A total of 473 patients were included, mean age of 46.9 ±11.3 years. Rheumatic disease was the most common etiology. In a mean follow-up period of 4.43 years, mortality rate was 16.1%. Patients with aortic prosthesis showed higher survival than patients with double implant (mitral and aortic) (p=0.026). Of the factors adjusted for mortality, only functional class and chronic renal failure showed statistically significant association. The incidence of PVT was 0.24/100 patients/year, and the first event occurred more than 1000 days after the implant. Smoking and pannus formation were significantly associated with PVT. No differences were found in INR variability between patients with and without thrombosis by prosthetic position, but significant differences were found in INR before thrombosis as compared with patients without thrombosis (INR= 2.20 [1.80-2.20] vs. 2.80 [2.20-3.40]; p= 0.040). The incidence of stroke and bleeding was 4.4% and 5.2% respectively.

CONCLUSIONS

The study population was young, and rheumatic valve disease was common in this group. The prevalence of PVT was similar to that described in the literature, despite the low income and low educational level of our sample.

Incidence and mechanisms of bioprosthetic dysfunction after transcatheter implantation of a mechanically-expandable heart valve

BACKGROUND

The mechanically-expandable transcatheter valve is no longer commercially available, yet clinical and echocardiographic surveillance is imperative for thousands of patients who received transcatheter aortic valve implantation (TAVI) with this platform.

AIMS

We aimed to determine the incidence and mechanism of bioprosthetic valve dysfunction (BVD) following TAVI with mechanically-expandable valves.

METHODS

From 2013 to 2020, all 234 patients who underwent TAVI with the LOTUS valve were included. BVD was categorised as (i) structural valve deterioration (SVD), (ii) non-structural valve dysfunction (NSVD), (iii) clinical valve thrombosis and (iv) endocarditis, according to the Valve Academic Research Consortium-3 criteria.

RESULTS

The mean age was 79±7 years, 60% were male, and the mean Society of Thoracic Surgeons score was 4.2±2.9%. The technical success rate was 94% and the 30-day device success rate was 78%. All-cause mortality at 1 year was 15%; median follow-up duration was 36 (IQR 18-60) months during which 47% of patients died. One hundred and three patients had ≥1 type of BVD (44%), which predominantly consisted of NSVD (39%, mostly because of ≥moderate patient-prosthesis mismatch). BVD during follow-up included endocarditis (3.4%), clinical valve thrombosis (3.4%) and SVD (1.3%). Both endocarditis and clinically apparent valve thrombosis occurred early and late after TAVI and resulted in valve-related deaths in 38% and 13% of patients, respectively. Overall, ≥moderate haemodynamic valve deterioration occurred in 5.5% and bioprosthetic failure in 7.3%, leading to valve-related deaths in 36% of cases.

CONCLUSIONS

BVD represents a relevant health issue after TAVI with a mechanically-expandable valve. Serious but reversible causes of BVD include endocarditis and clinically apparent valve thrombosis, both carrying a time-independent hazard post-TAVI.

Characterization of main pulmonary artery and valve annulus region of piglets using echocardiography, uniaxial tensile testing, and a novel non-destructive technique

Characterization of cardiovascular tissue geometry and mechanical properties of large animal models is essential when developing cardiovascular devices such as heart valve replacements. These datasets are especially critical when designing devices for pediatric patient populations, as there is often limited data for guidance. Here, we present a previously unavailable dataset capturing anatomical measurements and mechanical properties of juvenile Yorkshire (YO) and Yucatan (YU) porcine main pulmonary artery (PA) and pulmonary valve (PV) tissue regions that will inform pediatric heart valve design requirements for preclinical animal studies. In addition, we developed a novel radial balloon catheter-based method to measure tissue stiffness and validated it against a traditional uniaxial tensile testing method. YU piglets, which were significantly lower weight than YO counterparts despite similar age, had smaller PA and PV diameters (7.6-9.9 mm vs. 10.1-12.8 mm). Young's modulus (stiffness) was measured for the PA and the PV region using both the radial and uniaxial testing methods. There was no significant difference between the two breeds for Young's modulus measured in the elastic (YU PA 84.7 ± 37.3 kPa, YO PA 79.3 ± 15.7 kPa) and fibrous regimes (YU PA 308.6 ± 59.4 kPa, YO PA 355.7 ± 68.9 kPa) of the stress-strain curves. The two testing techniques also produced similar stiffness measurements for the PA and PV region, although PV data showed greater variation between techniques. Overall, YU and YO piglets had similar PA and PV diameters and tissue stiffness to previously reported infant pediatric patients. These results provide a previously unavailable age-specific juvenile porcine tissue geometry and stiffness dataset critical to the development of pediatric cardiovascular prostheses. Additionally, the data demonstrates the efficacy of a novel balloon catheter-based technique that could be adapted to non-destructively measure tissue stiffness in situ.

Implants with Sensing Capabilities

Because of the aging human population and increased numbers of surgical procedures being performed, there is a growing number of biomedical devices being implanted each year. Although the benefits of implants are significant, there are risks to having foreign materials in the body that may lead to complications that may remain undetectable until a time at which the damage done becomes irreversible. To address this challenge, advances in implantable sensors may enable early detection of even minor changes in the implants or the surrounding tissues and provide early cues for intervention. Therefore, integrating sensors with implants will enable real-time monitoring and lead to improvements in implant function. Sensor integration has been mostly applied to cardiovascular, neural, and orthopedic implants, and advances in combined implant-sensor devices have been significant, yet there are needs still to be addressed. Sensor-integrating implants are still in their infancy; however, some have already made it to the clinic. With an interdisciplinary approach, these sensor-integrating devices will become more efficient, providing clear paths to clinical translation in the future.

Device Failure in Bicuspid Aortic Stenosis Following Transcatheter Aortic Valve Implantation

Recent studies showed the favorable outcomes of transcatheter aortic valve implantation (TAVI) in patients with bicuspid aortic valve (BAV) stenosis. However, data on the relation between BAV morphology and optimal transcatheter heart valve (THV) selection are limited. This study sought to evaluate the determinants of device performance in patients with BAV who underwent TAVI. Consecutive patients with BAV who underwent TAVI with the SAPIEN 3 from multicenters were evaluated. Outcomes were the incidence and predictors of device failure. Device failure was defined as peak aortic velocity >3.0 m/s, mean pressure gradient >20 mm Hg, moderate or severe paravalvular leakage and/or procedure mortality. A total of 187 patients with BAV were identified, aged 77 years, and 38.0% were women. A total of 37 patients (19.8%) were treated with 23-mm valve, 58 (31.0%) with 26-mm valve, and 92 (49.2%) with 29-mm valve. Predischarge echocardiogram demonstrated 37 patients (19.8%) with device failure. BAV with excessive leaflet calcification plus calcified raphe (EC-BAV) (OR 16.7, 95% CI 1.99 to 39.6) and smaller THV (OR 4.41, 95% CI 1.43 to 13.6) were independently associated with increased risk of device failure. In addition, 4.0%, 5.1%, and 11.1% of device failures were observed in patients without EC-BAV who underwent TAVI with 23-, 26- and 29-mm THV (p = 0.47), respectively, and 91.7%, 31.6% and 23.2% in those with EC-BAV, respectively (p <0.001). In conclusion, EC-BAV morphology was the major determinant of a device failure after TAVI. Moreover, TAVI in patients with EC-BAV requiring small SAPIEN 3 could be challenging. Further data on device and treatment selection in patients with BAV are still warranted.

Surgical Management of Complex Aortic Valve Disease in Young Adults: Repair, Replacement, and Future Alternatives

The ideal aortic valve substitute in young adults remains unknown. Prosthetic valves are associated with a suboptimal survival and carry a significant risk of valve-related complications in young patients, mainly reinterventions with tissue valves and, thromboembolic events and major bleeding with mechanical prostheses. The Ross procedure is the only substitute that restores a survival curve similar to that of a matched general population, and permits a normal life without functional limitations. Though the risk of reintervention is the Achilles' heel of this procedure, it is very low in patients with aortic stenosis and can be mitigated in patients with aortic regurgitation by tailored surgical techniques. Finally, the Ozaki procedure and the transcatheter aortic valve implantation are seen by many as future alternatives but lack evidence and long-term follow-up in this specific patient population.

Mechanical aortic valve prostheses offer a survival benefit in 50-65 year olds: AUTHEARTVISIT study

BACKGROUND

The present population-based cohort study investigated long-term mortality after surgical aortic valve replacement (AVR) with bioprosthetic (B) or mechanical aortic valve prostheses (M) in a European social welfare state.

METHODS

We analysed patient data from health insurance records covering 98% of the Austrian population between 2010 and 2018. Subsequent patient-level record linkage with national health data provided patient characteristics and clinical outcomes. Further reoperation, myocardial infarction, heart failure and stroke were evaluated as secondary outcomes.

RESULTS

A total of 13,993 patients were analysed and the following age groups were examined separately: <50 years (727 patients: 57.77% M, 42.23% B), 50-65 years (2612 patients: 26.88% M, 73.12% B) and >65 years (10,654 patients: 1.26% M, 98.74% B). Multivariable Cox regression revealed that the use of B-AVR was significantly associated with higher mortality in patients aged 50-65 years compared to M-AVR (HR = 1.676 [1.289-2.181], p < 0.001). B-AVR also performed worse in a competing risk analysis regarding reoperation (HR = 3.483 [1.445-8.396], p = 0.005) and myocardial infarction (HR = 2.868 [1.255-6.555], p = 0.012). However, the risk of developing heart failure and stroke did not differ significantly after AVR in any age group.

CONCLUSIONS

Patients aged 50-65 years who underwent M-AVR had better long-term survival, and a lower risk of reoperation and myocardial infarction. Even though anticoagulation is crucial in patients with M-AVR, we did not observe significantly increased stroke rates in patients with M-AVR. This evident survival benefit in recipients of mechanical aortic valve prostheses aged <65 years critically questions current guideline recommendations.

Meta-Analysis Comparing Risk Factors, Incidence, and Outcomes of Patients With Versus Without Prosthesis-Patient Mismatch Following Transcatheter Aortic Valve Implantation

Current guidelines on the management of patients with aortic valvular disease have widened the use of transcatheter aortic valve implantation (TAVI) with an emphasis on avoidance of prosthesis-patient mismatch (PPM). This study sought to examine the incidence, risk factors, and all-cause mortality of PPM after TAVI. Medline and Embase databases were searched from inception to August 10, 2021. Patients were compared along 2 arms: (1) any degree of PPM and those without PPM, (2) severe PPM, and nonsevere PPM. A total of 22 articles involving 115,442 patients after TAVI were included. Pooled incidence for any degree of PPM was 30.1% and 10.7% in severe PPM. Incidence was significantly higher (p <0.001) for any degree of PPM in Europe (33.1%) and North America (34.4%) compared with Asia (10.4%). Incidence of severe PPM was higher (p = 0.015) in older generation (13.6%) compared with current-generation valves (6.3%). Severe PPM increased the risk of all-cause mortality relative to nonsevere PPM (hazard ratio: 1.86, 95% confidence interval: 1.05 to 3.29, p = 0.034). Patients of younger age, increased body surface area, lower left ventricular ejection fraction, and classified New York Heart Association Class III/IV were at greater risk of both any degree and severe PPM. Smaller prosthesis size increased the risk of any degree of PPM, whereas postdilation and larger prostheses were protective factors. In conclusion, all-cause mortality was significantly affected in severe PPM compared with nonsevere cases, whereas this excess mortality was not observed between those with any degree of PPM and those without. Closer attention to patient and bioprosthetic valve factors is required to minimize the occurrence of severe PPM.

Bioprosthetic aortic valve replacement in patients aged 50 years old and younger: Structural valve deterioration at long-term follow-up. Retrospective study

Background

Structural valve deterioration (SVD) remains the major determinant of bioprosthesis durability. The aim of this study was to investigate the SVD incidence, predictors and outcomes in patients aged 50 years and younger after bioprosthetic aortic valve replacement (bAVR).

Methods

We retrospectively analyzed 73 consecutive patients ≤50 years old who underwent bioprosthetic AVR at our center between 2005 and 2015. Median age at surgery was 44 (interquartile range [IQR]: 39-47) years. Follow-up was 93.2% complete at a median time of 7.2 (IQR: 5.5-9.5) years. Cumulative follow-up was 545.5 valve-years. Bioprosthesis SVD was determined by strict echocardiographic assessment.

Results

The overall survival-rate at 10/15 years and freedom from SVD at 10/12.5 years were 89.6 ± 5.2%/81.5 ± 9.1% and 73.5 ± 8.2%/41.9 ± 18.9%, respectively. SVD occurred at a median time of 8.2 (IQR: 6.0-9.9) years after bAVR. Age was not found as an independent predictor for SVD at the multivariable model, despite a higher rate of SVD in the age group ≤30 years. Freedom from reoperation due to SVD at 10/15 years was 71.3 ± 14.1%/13.6 ± 12.3%. Reoperation was performed at a median time of 10.0 (IQR: 8.9-11.9) years since first bAVR and was associated with a 100% 12-month survival.

Conclusions

In our study, the rate and time of SVD occurrence were comparable to those of other studies' older age groups. Strict echocardiographic monitoring of valve performance is mandatory to set the appropriate timing of eventual reoperation. This attitude can improve outcomes of bAVR in younger patients.

Mechanical versus Bioprosthetic Valve for Aortic Valve Replacement: Systematic Review and Meta-Analysis of Reconstructed Individual Participant Data

OBJECTIVES

To compare biological versus mechanical aortic valve replacement.

METHODS

We searched MEDLINE, Scopus, and Cochrane Library databases for randomized clinical trials and propensity-score matched studies published by October 14th, 2021 according to PRISMA statement. Individual patient data on overall survival were extracted. One- and two-stage survival analyses, and random-effects meta-analyses were conducted.

RESULTS

25 studies were identified, incorporating 8,721 bioprosthetic and 8,962 mechanical valves:. In the one-stage meta-analysis, mechanical valves cumulatively demonstrated decreased hazard for mortality (Hazard Ratio [HR] : 0.79, 95% Confidence interval [CI] : 0.74-0.84, p < 0.0001). Overall survival was similar between the compared arms for patients <50 years old (HR: 0.88, 95% CI : 0.71-1.1, p = 0.216), increased in the mechanical valve arm for patients 50-70 years old (HR : 0.76, 95% CI : 0.70-0.83, p < 0.0001), and increased in the bioprosthetic arm for patients >70 years old (HR : 1.35, 95% CI : 1.17-1.57, p < 0.0001). Meta-regression analysis revealed that the survival in the 50-70 years old group was not influenced by the publication year of the individual studies. No statistically significant difference was observed regarding in-hospital mortality, post-operative strokes and post-operative reoperation. All-cause mortality was found decreased in the mechanical group, cardiac mortality was comparable between the two groups, major bleeding rates were increased in the mechanical valve group, and reoperation rates were increased in the bioprosthetic valve group.

CONCLUSIONS

Survival rates seem to not be influenced by the type of prosthesis in patients <50 years old. A survival advantage in favour of mechanical valves is observed in patients 50-70 years old, while in patients >70 years old bioprosthetic valves offer better survival outcomes.

When Is It Preferable to Use Warfarin?

Warfarin Versus Direct Oral AnticoagulantsDespite the growing popularity of DOACs, data in specific populations have provided a stark reminder that the equivalence (or superiority) of DOACs to warfarin cannot be assumed across the board. These results have raised an increasingly common clinical question: When is it preferable to use warfarin?

Dynamic Echocardiographic Imaging of a Valve-in-Valve Mitral Prosthesis

Dynamic imaging of heart valves and specifically prosthetic valves is a central benefit of echocardiography. Most bioprosthetic heart valves degenerate over a given time and hence require repeat valve replacement which carries a significant risk of morbidity and mortality. Reoperation is the standard of care and may still be required after the first successful surgery due to complications disrupting either mechanical or bioprosthetic valves. Such complications can be delayed or even prevented if optimal prosthesis selection is individualized according to patients’ medical and postimplantation follow-up. We present the case of an 84-year-old woman where an open-heart valve-in-valve approach, implanting a mechanical valve in a failed bioprosthetic valve, produced a unique image on transthoracic echocardiography which needs to be recognized by imagers for appropriate patient diagnosis and management.

Poly-2-methyl-2-oxazoline–modified bioprosthetic heart valve leaflets have enhanced biocompatibility and resist structural degeneration

Bioprosthetic heart valves (BHV) fabricated from glutaraldehyde-fixed heterograft tissue, such as bovine pericardium (BP), are widely used for treating heart valve disease, a group of disorders that affects millions. Structural valve degeneration (SVD) of BHV due to both calcification and the accumulation of advanced glycation end products (AGE) with associated serum proteins limits durability. We hypothesized that BP modified with poly-2-methyl-2-oxazoline (POZ) to inhibit protein entry would demonstrate reduced accumulation of AGE and serum proteins, mitigating SVD. In vitro studies of POZ-modified BP demonstrated reduced accumulation of serum albumin and AGE. BP-POZ in vitro maintained collagen microarchitecture per two-photon microscopy despite AGE incubation, and in cell culture studies was associated with no change in tumor necrosis factor-α after exposure to AGE and activated macrophages. Comparing POZ and polyethylene glycol (PEG)–modified BP in vitro, BP-POZ was minimally affected by oxidative conditions, whereas BP-PEG was susceptible to oxidative deterioration. In juvenile rat subdermal implants, BP-POZ demonstrated reduced AGE formation and serum albumin infiltration, while calcification was not inhibited. However, BP-POZ rat subdermal implants with ethanol pretreatment demonstrated inhibition of both AGE accumulation and calcification. Ex vivo laminar flow studies with human blood demonstrated BP-POZ enhanced thromboresistance with reduced white blood cell accumulation. We conclude that SVD associated with AGE and serum protein accumulation can be mitigated through POZ functionalization that both enhances biocompatibility and facilitates ethanol pretreatment inhibition of BP calcification.

Surgical Management of Valvular Heart Disease in Mucopolysaccharidoses: A Review of Literature

Mucopolysaccharidoses are extremely rare diseases that are frequently presenting with structural heart problems of the aortic and mitral valve in combination with myocardial dysfunction. In a substantial proportion, this leads to heart failure and is a leading cause of death in these patients. As this glycosaminoglycan degradation defect is associated with other conditions strongly influencing the perioperative risk and choice of surgical technique, multidisciplinary planning is crucial to improve short- and long-term outcomes. The extensive variance in clinical presentation between different impaired enzymes, and further within subgroups, calls for personalised treatment plans. Enzyme replacement therapies and bone marrow transplantation carry great potential as they may significantly abrogate the progress of the disease and as such reduce the clinical burden and improve life expectancy. Nevertheless, structural heart interventions may be required. We reviewed the existing literature of the less than 50 published cases regarding surgical management, technique, and choice of prostheses. Although improvement in therapy has shown promising results in protecting valvar tissue when initiated in infancy, concerns regarding stability of this effect and durability of biological prostheses remain.

Effects of membrane and flexural stiffnesses on aortic valve dynamics: identifying the mechanics of leaflet flutter in thinner biological tissues

Valvular pathologies that induce deterioration in the aortic valve are a common cause of heart disease among aging populations. Although there are numerous available technologies to treat valvular conditions and replicate normal aortic function by replacing the diseased valve with a bioprosthetic implant, many of these devices face challenges in terms of long-term durability. One such phenomenon that may exacerbate valve deterioration and induce undesirable hemodynamic effects in the aorta is leaflet flutter, which is characterized by oscillatory motion in the biological tissues. While this behavior has been observed for thinner bioprosthetic valves, the specific underlying mechanics that lead to leaflet flutter have not previously been identified. This work proposes a computational approach to isolate the fundamental mechanics that induce leaflet flutter in thinner biological tissues during the cardiac cycle. The simulations in this work identify reduced flexural stiffness as the primary factor that contributes to increased leaflet flutter in thinner biological tissues, while decreased membrane stiffness and mass of the thinner tissues do not directly induce flutter in these valves. The results of this study provide an improved understanding of the mechanical tissue properties that contribute to flutter and offer significant insights into possible developments in the design of bioprosthetic tissues to account for and reduce the incidence of flutter.

Patient-Prosthesis Mismatch in Contemporary Small-Size Mechanical Prostheses Does Not Impact Survival at 10 Years

BACKGROUND

The effect of PPM in mechanical prostheses on long-term survival is not well-established.

METHODS

Patients who received a 21 mm or smaller aortic valve between 2000 and 2011 were retrospectively analyzed (n = 416). Propensity matching was used in order to account for baseline differences in patient subgroups (PPM vs. no PPM; severe PPM vs. no severe PPM).

RESULTS

Five- and ten-year survival was 78 ± 3.52% and 64.51 ± 4.51% in patients with PPM, versus 83.3 ± 3.12% and 69.37 ± 4.36% in patients without (p = 0.28) when analyzed at 10.39 ± 5.25 years after the primary procedure. Independent risk factors for impaired survival, after matching, were age, serum creatinine, and severe pulmonary hypertension. Five- and ten-year survival in patients with severe PPM was 73.34 ± 6.01% and 61.76 ± 8.17%, respectively, versus 74.72 ± 5.68% and 67.50 ± 7.09% in those without (p = 0.49), at 8.82 ± 5.17 years after SAVR. Age was the only independent variable that influenced long-term survival when severe PPM was added to the model.

CONCLUSIONS

PPM or severe PPM does not impact long-term survival up to 10 years in mechanical valve recipients when matching for preoperative variables.

Anisotropic elastic behavior of a hydrogel-coated electrospun polyurethane: Suitability for heart valve leaflets

Although xenograft biomaterials have been used for decades in replacement heart valves, they continue to face multiple limitations, including limited durability, mineralization, and restricted design space due to their biological origins. These issues necessitate the need for novel replacement heart valve biomaterials that are durable, non-thrombogenic, and compatible with transcatheter aortic valve replacement devices. In this study, we explored the suitability of an electrospun poly(carbonate urethane) (ES-PCU) mesh coated with a poly(ethylene glycol) diacrylate (PEGDA) hydrogel as a synthetic biomaterial for replacement heart valve leaflets. In this material design, the mesh provides the mechanical support, while the hydrogel provides the required surface hemocompatibility. We conducted a comprehensive study to characterize the structural and mechanical properties of the uncoated mesh as well as the hydrogel-coated mesh (composite biomaterial) over the estimated operational range. We found that the composite biomaterial was functionally robust with reproducible stress-strain behavior within and beyond the functional ranges for replacement heart valves, and was able to withstand the rigors of mechanical evaluation without any observable damage. In addition, the composite biomaterial displayed a wide range of mechanical anisotropic responses, which were governed by fiber orientation of the mesh, which in turn, was controlled with the fabrication process. Finally, we developed a novel constitutive modeling approach to predict the mechanical behavior of the composite biomaterial under in-plane extension and shear deformation modes. This model identified the existence of fiber-fiber mechanical interactions in the mesh that have not previously been reported. Interestingly, there was no evidence of fiber-hydrogel mechanical interactions. This important finding suggests that the hydrogel coating can be optimized for hemocompatibility independent of the structural mechanical responses required by the leaflet. This initial study indicated that the composite biomaterial has mechanical properties well-suited for replacement heart valve applications and that the electrospun mesh microarchitecture and hydrogel biological properties can be optimized independently. It also reveals that the structural mechanisms contributing to the mechanical response are more complicated than what was previously established and paves the pathway for more detailed future studies.

Leaflet Tissue Generation from Microfibrous Heart Valve Leaflet Scaffolds with Native Characteristics

Mechanical and bioprosthetic valves that are currently applied for replacing diseased heart valves are not fully efficient. Heart valve tissue engineering may solve the issues faced by the prosthetic valves in heart valve replacement. The leaflets of native heart valves have a trilayered structure with layer-specific orientations; thus, it is imperative to develop functional leaflet tissue constructs with a native trilayered, oriented structure. Its key solution is to develop leaflet scaffolds with a native morphology and structure. In this study, microfibrous leaflet scaffolds with a native trilayered and oriented structure were developed in an electrospinning system. The scaffolds were implanted for 3 months in rats subcutaneously to study the scaffold efficiencies in generating functional tissue-engineered leaflet constructs. These in vivo tissue-engineered leaflet constructs had a trilayered, oriented structure similar to native leaflets. The tensile properties of constructs indicated that they were able to endure the hydrodynamic load of the native heart valve. Collagen, glycosaminoglycans, and elastin─the predominant extracellular matrix components of native leaflets─were found sufficiently in the leaflet tissue constructs. The residing cells in the leaflet tissue constructs showed vimentin and α-smooth muscle actin expression, i.e., the constructs were in a growing state. Thus, the trilayered, oriented fibrous leaflet scaffolds produced in this study could be useful to develop heart valve scaffolds for successful heart valve replacements.

Impact of Healthcare-Associated Infections Connected to Medical Devices-An Update

Healthcare-associated infections (HAIs) are caused by nosocomial pathogens. HAIs have an immense impact not only on developing countries but also on highly developed parts of world. They are predominantly device-associated infections that are caused by the planktonic form of microorganisms as well as those organized in biofilms. This review elucidates the impact of HAIs, focusing on device-associated infections such as central line-associated bloodstream infection including catheter infection, catheter-associated urinary tract infection, ventilator-associated pneumonia, and surgical site infections. The most relevant microorganisms are mentioned in terms of their frequency of infection on medical devices. Standard care bundles, conventional therapy, and novel approaches against device-associated infections are briefly mentioned as well. This review concisely summarizes relevant and up-to-date information on HAIs and HAI-associated microorganisms and also provides a description of several useful approaches for tackling HAIs.

Transcatheter solutions for transcatheter aortic valve replacement dysfunction: is redo transcatheter aortic valve replacement a durable option?

As transcatheter aortic valve replacement (TAVR) expands into a younger and lower risk cohort of patients, many important clinical questions are raised, including the one of overall valve durability. Bioprosthetic valve dysfunction (BVD) is a complex clinical issue, of which structural valve deterioration (SVD) is a subcategory. Similar to surgical bioprosthesis, transcatheter heart valves (THVs) can fail over the years however, data on long-term THVs durability is lacking, especially in the lower risk cohort. Surgical explant with open aortic surgery or a second THV, described as redo-TAVR, are feasible options when the first THV fails. However long-term data in these patients is even more limited. Important clinical considerations such as the mechanism(s) of THV dysfunction, the type and timing of the second procedure must be carefully considered. There are also inherently important clinical concerns regarding redo-TAVR, such as coronary access and higher post procedure gradients. In the present keynote lecture, we review the diagnosis of THV dysfunction and transcatheter options available when SVD occurs.

Prognostic impact of identifying etiology of prosthetic valve dysfunction with CT

BACKGROUND

In patients with prosthetic heart valves (PHV), there are distinct treatment implications based on prosthetic valve dysfunction (PVD) etiology. We investigated whether evaluation for PVD etiology on computed tomography (CT) has prognostic value for adverse clinical outcomes.

METHODS

Consecutive patients with suspected PVD that had a clinically indicated contrast chest CT and echocardiogram done within 1 year of each other were identified retrospectively from the Prosthetic Heart Valve CT Registry at the University of Minnesota. CTs and echocardiograms were assessed for potential PVD etiologies of pannus, structural valve degeneration (SVD) and thrombus, as per standard guidelines. Kaplan-Meier and Cox regression analyses were performed to assess association with a composite outcome of reoperation and all-cause mortality.

RESULTS

132 patients (51.5% male, mean age 62.1 ​± ​19.3 years) with suspected PVD were included. There were 97 tissue valves, 31 mechanical valves and 4 transcatheter valves. The location of the valve was as follows: 72 aortic, 45 mitral, 8 tricuspid, and 7 pulmonic. A PVD etiology was diagnosed on CT in 80 (60.6%) patients, and on echocardiography in 45 (34.1%) patients, largely driven by a diagnosis of SVD on both modalities. Significant univariate predictors of the composite outcome included CT diagnosis of SVD (P ​< ​0.001), echocardiography diagnosis of SVD (P ​< ​0.001), degree of prosthetic stenosis (P ​< ​0.001) and degree of prosthetic regurgitation (P ​< ​0.001). On multivariable analyses adjusted for age, sex, left ventricular function, degree of prosthetic stenosis and degree of prosthetic regurgitation, CT diagnosis of SVD was significantly associated with the composite outcome (HR: 1.79, 1.09-2.95) whereas echocardiography diagnosis of SVD was not (HR: 1.56, 0.98-2.46).

CONCLUSION

In patients with suspected PVD, CT assessment of SVD had prognostic significance for hard outcomes. CT should be considered in the diagnostic evaluation of patients with suspected PVD.

Early outcomes of transatrial mitral valve replacement in severe mitral annular calcification

Objective

Mitral valve replacement (MVR) in the setting of severe mitral annular calcification is a technically challenging operation with increased morbidity and mortality. Transseptal/apical transcatheter MVR (TMVR) in mitral annular calcification has emerged as an option for these cases, although may not be feasible due to anatomical reasons. Transatrial TMVR is a potential treatment option for this subgroup of patients.

Methods

Patients who underwent transatrial TMVR between June 2018 and November 2020 at a single institution were included. Patients were selected by a structural heart team based on their surgical risk, pattern of mitral annular calcification, risk of valve migration, left ventricular outflow obstruction, and paravalvular leak.

Results

A total of 11 patients underwent transatrial TMVR. Mean patient age was 74.2 years and mean Society of Thoracic Surgeons predicted risk of mortality score was 9.1%. All patients had the presence of both mitral stenosis and regurgitation—dominant etiology—was mitral stenosis in 81.2%, and mitral regurgitation in 18.8%. Among patients, 54.5% had a concomitant cardiac procedure. There was no in-hospital or 30-day mortality. Technical success defined by the Mitral Valve Academic Research Consortium was achieved in 90.9% of patients. Postoperative paravalvular leak was mild or less in all patients.

Conclusions

In this series, transatrial TMVR was shown to be a safe and effective treatment option for patients who are high risk for surgical MVR and should be in surgeons' armamentarium in the treatment of this high-risk patient population. Dissemination of safe technique will be critical in the successful conduct of this surgery.

Long-Term Stability and Biocompatibility of Pericardial Bioprosthetic Heart Valves

The use of bioprostheses for heart valve therapy has gradually evolved over several decades and both surgical and transcatheter devices are now highly successful. The rapid expansion of the transcatheter concept has clearly placed a significant onus on the need for improved production methods, particularly the pre-treatment of bovine pericardium. Two of the difficulties associated with the biocompatibility of bioprosthetic valves are the possibilities of immune responses and calcification, which have led to either catastrophic failure or slow dystrophic changes. These have been addressed by evolutionary trends in cross-linking and decellularization techniques and, over the last two decades, the improvements have resulted in somewhat greater durability. However, as the need to consider the use of bioprosthetic valves in younger patients has become an important clinical and sociological issue, the requirement for even greater longevity and safety is now paramount. This is especially true with respect to potential therapies for young people who are afflicted by rheumatic heart disease, mostly in low- to middle-income countries, for whom no clinically acceptable and cost-effective treatments currently exist. To extend longevity to this new level, it has been necessary to evaluate the mechanisms of pericardium biocompatibility, with special emphasis on the interplay between cross-linking, decellularization and anti-immunogenicity processes. These mechanisms are reviewed in this paper. On the basis of a better understanding of these mechanisms, a few alternative treatment protocols have been developed in the last few years. The most promising protocol here is based on a carefully designed combination of phases of tissue-protective decellularization with a finely-titrated cross-linking sequence. Such refined protocols offer considerable potential in the progress toward superior longevity of pericardial heart valves and introduce a scientific dimension beyond the largely disappointing 'anti-calcification' treatments of past decades.

Transcatheter Mitral Valve Implantation: Current Status and Future Perspectives

Mitral transcatheter therapies represent the treatment of choice for all patients deemed unsuitable for cardiac surgery. So far, the largest clinical experience has been limited to percutaneous repair techniques. However, given the complexity and heterogeneity of mitral valve anatomy and pathology, transcatheter mitral valve implantation will widen the mitral valve therapies horizon, toward a patient-tailored approach. Current data about transcatheter mitral valve implantation is still limited and, although some data are promising, there are still some issues to be addressed. This review provides a comprehensive insight into the available devices and describes potential advantages and limitations of transcatheter mitral valve implantation.

A novel alternative: transapical transcatheter mitral valve-in-valve implantation using J-Valve for failed bioprosthesis

BACKGROUND

Failed mitral bioprosthesis has conventionally been treated with redo surgical mitral valve replacement (SMVR). Transcatheter mitral valve-in-valve implantation (TM-VIVI) is emerging as an alternative to SMVR in high-risk patients. We report our experience with transapical TM-VIVI using the J-Valve system.

METHODS

From May 2020 to January 2021, 21 patients with a failed mitral bioprosthesis underwent transapical TM-VIVI without concomitant procedures at Guangdong Provincial People's hospital. The mean age was 74.62 years. All patients were heavily symptomatic with severe mitral regurgitation and increased trans-prosthetic gradient. The Society of Thoracic Surgeons predicted risk of mortality (STS PROM) and European System for Cardiac Operative Risk Evaluation II (EuroScore II) scores were used and predicted high mortality (STS PROM, 12.91%±9.94%; EuroScore II, 12.04%±10.5%). All the procedures were performed in a hybrid room.

RESULTS

The success rate was 100% with no conversion to median sternotomy and no intraprocedural death. The mean ventilation time and intensive care unit (ICU) stay were 25±21.44 minutes and 4.14±7.08 days, respectively. No major postoperative complications were observed, except 1 patient suffered pneumonia and required tracheostomy. All patients recovered well. Postoperative echocardiography revealed excellent hemodynamics with no residual mitral regurgitation in 19 patients and mild regurgitation in 2 patients. In a subgroup analysis, no significant differences among procedural and postoperative outcomes were detected in patients with previous aortic-mitral double valve replacement (DVR) compared to other patients.

CONCLUSIONS

Our results demonstrate the safety and feasibility of transapical TM-VIVI using the J-Valve system, even in patients following DVR.