Progress on a Novel, 3D-Printable Heart Valve Prosthesis.

(1) Background: Polymeric heart valves are prostheses constructed out of flexible, synthetic materials to combine the advantageous hemodynamics of biological valves with the longevity of mechanical valves. This idea from the early days of heart valve prosthetics has experienced a renaissance in recent years due to advances in polymer science. Here, we present progress on a novel, 3D-printable aortic valve prosthesis, the TIPI valve, removing the foldable metal leaflet restrictor structure in its center. Our aim is to create a competitive alternative to current valve prostheses made from flexible polymers. (2) Methods: Three-dimensional (3D) prototypes were designed and subsequently printed in silicone. Hemodynamic performance was measured with an HKP 2.0 hemodynamic testing device using an aortic valve bioprosthesis (BP), a mechanical prosthesis (MP), and the previously published prototype (TIPI 2.2) as benchmarks. (3) Results: The latest prototype (TIPI 3.4) showed improved performance in terms of regurgitation fraction (TIPI 3.4: 15.2 ± 3.7%, TIPI 2.2: 36.6 ± 5.0%, BP: 8.8 ± 0.3%, MP: 13.2 ± 0.7%), systolic pressure gradient (TIPI 3.4: 11.0 ± 2.7 mmHg, TIPI 2.2: 12.8 ± 2.2 mmHg, BP: 8.2 ± 0.9 mmHg, MP: 10.5 ± 0.6 mmHg), and effective orifice area (EOA, TIPI 3.4: 1.39 cm2, TIPI 2.2: 1.28 cm2, BP: 1.58 cm2, MP: 1.38 cm2), which was equivalent to currently used aortic valve prostheses. (4) Conclusions: Removal of the central restrictor structure alleviated previous concerns about its potential thrombogenicity and significantly increased the area of unobstructed opening. The prototypes showed unidirectional leaflet movement and very promising performance characteristics within our testing setup. The resulting simplicity of the shape compared to other approaches for polymeric heart valves could be suitable not only for 3D printing, but also for fast and easy mass production using molds and modern, highly biocompatible polymers.

Gender-Related Outcomes after Surgical Resection and Level of Satisfaction in Patients with Left Atrial Tumors.

BACKGROUND: Cardiac tumors are rare, with a low incidence of between 0.0017 and 0.19%. The majority of cardiac tumors are benign and predominantly occur in females. The aim of our study was to examine how outcomes differ between men and women. METHODS: From 2015 to 2022, 80 patients diagnosed with suspected myxoma were operated on. In all patients, preoperative, perioperative, and postoperative data were recorded. Such patients were identified and included in a retrospective analysis focused on gender-related differences. RESULTS: Patients were predominantly female (n = 64; 80%). The mean age was 62.76 ± 13.42 years in female patients and 59.65 ± 15.84 years in male patients (p = 0.438). The body mass index (BMI) was comparable in both groups: between 27.36 ± 6.16 in male and 27.09 ± 5.75 (p = 0.945) in female patients. Logistic EuroSCORE (LogES) (female: 5.89 ± 4.6; male: 3.95 ± 3.06; p = 0.017) and EuroSCORE II (ES II) (female: 2.07 ± 2.1; male: 0.94 ± 0.45; p = 0.043), both scores to predict the mortality in cardiac surgery, were significantly higher in female patients. Two patients died early, within 30 days after surgery: one male and one female patient. Late mortality was defined as the 5-year survival rate, which was 94.8%, and 15-year survival rate, which was 85.3% in our cohort. Causes of death were not related to the primary tumor operation. The follow up showed that satisfaction with surgery and long-term outcome was high. CONCLUSION: Predominately female patients presented with left atrial tumors over a 17-year period. Relevant gender differences aside from that were not evident. Surgery could be performed with excellent early (within 30 days after surgery) and late results (follow up after discharge).

What Exactly Makes Age a Risk Factor for an Unfavorable Outcome after Mitral Valve Surgery?

Objective: Age has an undeniable impact on perioperative mortality. However, it is not necessarily a predictor of frailty per se, as older patients have different outcomes. To verify specific conditions underlying frailty, we examined demographics, comorbidities, frequency, and distribution of postoperative complications influencing outcomes in a challenging cohort of patients undergoing mitral valve surgery. Methods: The study enrolled 1627 patients who underwent mitral valve surgery. Patients younger than 40 years who had been diagnosed with endocarditis were excluded. Patients were divided into three groups with ages ranging from 40−59 (n = 319), 60−74 (n = 795), and >75 years (n = 513). Baseline, comorbidities, postoperative complications, and mortality were recorded. Results: The older the patients were, the more frequently they suffered from pre- and postoperative renal insufficiency (p < 0.001). The likelihood of postoperative renal failure requiring dialysis was significantly higher with pre-existing renal failure. There was a significant association between postoperative renal insufficiency and the development of postoperative pleural or pericardial effusion (p < 0.001, p = 0.016). A significant decrease in BMI was observed in patients >75 years of age compared to the 60−74 years group (27.3 vs. 28.2 kg/m2, p = 0.007). The development of critical illnesses such as myopathy and neuropathy (CIP/CIM) was age-dependent and increased significantly with age (p = 0.04). Hospitalization duration and mortality also increased significantly with age (p = 0.013, p < 0.001). Conclusions: It appears that elderly patients with advanced renal failure have a significantly higher risk of mortality, postoperative renal failure, need for dialysis, and possibly the development of pleural and pericardial effusions in mitral valve surgery. In addition, more frequent CIP/CIM with concomitant decrease in BMI in the most advanced age group indicate sarcopenia and thus an additional feature of frailty besides renal failure.

Engineering a New Polymeric Heart Valve Using 3D Printing-TRISKELION.

Background and Objectives: Developing a prosthetic heart valve that combines the advantageous hemodynamic properties of its biological counterpart with the longevity of mechanical prostheses has been a major challenge for heart valve development. Anatomically inspired artificial polymeric heart valves have the potential to combine these beneficial properties, and innovations in 3D printing have given us the opportunity to rapidly test silicone prototypes of new designs to further the understanding of biophysical properties of artificial heart valves. TRISKELION is a promising prototype that we have developed, tested, and further improved in our institution. Materials and Methods: STL files of our prototypes were designed with FreeCad 0.19.2 and 3D printed with an Agilista 3200W (Keyence, Osaka, Japan) using silicones of Shore hardness 35 or 65. Depending on the valve type, the support structures were printed in AR-M2 plastics. The prototypes were then tested using a hemodynamic pulse duplicator (HKP 2.0) simulating an aortic valve cycle at 70 bpm with 70 mL stroke volume (cardiac output 4.9 L/min). Valve opening cycles were visualized with a high-speed camera (Phantom Miro C320). The resulting values led to further improvements of the prototype (TRISKELION) and were compared to a standard bioprosthesis (Edwards Perimount 23 mm) and a mechanical valve (Bileaflet valve, St. Jude Medical). Results: We improved the silicone prototype with currently used biological and mechanical valves measured in our setup as benchmarks. The regurgitation fractions were 22.26% ± 4.34% (TRISKELION) compared to 8.55% ± 0.22% (biological) and 13.23% ± 0.79% (mechanical). The mean systolic pressure gradient was 9.93 ± 3.22 mmHg (TRISKELION), 8.18 ± 0.65 mmHg (biological), and 10.15 ± 0.16 mmHg (mechanical). The cardiac output per minute was at 3.80 ± 0.21 L/min (TRISKELION), 4.46 ± 0.01 L/min (biological), and 4.21 ± 0.05 L/min (mechanical). Conclusions: The development of a heart valve with a central structure proves to be a promising concept. It offers another principle to address the problem of longevity in currently used heart valves. Using 3D printing to develop new prototypes provides a fast, effective, and accurate way to deepen understanding of its physical properties and requirements. This opens the door for translating and combining results into modern prototypes using highly biocompatible polymers, internal structures, and advanced valve layouts.

CALA: Cumulative Volume of Calcified Lesions of the Aorta in Cardiac Surgery.

One of the major key questions raised in this retrospective study was to identify any correlation of atherosclerotic plaque volume of the ascending aorta and aortic arch with adverse events such as postoperative stroke, critical illness polyneuropathy and myopathy, as well as delirium and all-cause in-hospital mortality. In a second phase of this study, we investigated the relationship between atherosclerotic plaque volume and adverse events regarding the construction of proximal anastomosis on coronary artery bypass grafting procedures using different clamping techniques such as construction of anastomosis on cross-clamping or cross-clamping plus consecutive partial clamping of the aorta. The key findings of our research were that the size of calcium lesions of the ascending aorta and aortic arch correlates with early mortality, critical illness polyneuropathy/myopathy, and delirium but not with stroke. On the other hand, there were no significant differences between isolated cross-clamping versus cross-clamping plus consecutive partial clamping of the aorta regarding the primary adverse events by means of mean plaque volume.

First successful transcatheter valve-in-valve implantation into a failed mechanical prosthetic aortic valve facilitated by fracturing of the leaflets: a case report.

BACKGROUND: Degenerated and failed bioprosthetic cardiac valves can safely be treated with transcatheter valve-in-valve implantation in patients at high risk for reoperation. So far, non-functional mechanical valves must be treated with a surgical redo. Breaking the carbon leaflets before implanting a transcatheter valve into the remaining ring has never been described before. CASE SUMMARY: Here, we present the case of a 65-year-old male patient with severe heart failure, poor left ventricular function based on a fully immobile disc of his mechanical bileaflet aortic valve implanted 7 years ago. After the heart team declined to reoperate the patient due to his extremely high risk, we considered a transcatheter valve-in-valve implantation as the ultimate treatment approach. After successful interventional cracking of the leaflets in vitro, this approach, together with implanting a balloon-expandable transcatheter aortic valve replacement (TAVR) into the remaining ring, was performed under cerebral protection. The intervention resulted in a fully functional TAVR, improvement of heart function, and early discharge from the hospital. DISCUSSION: This case demonstrates the possibility to implant a transcatheter valve successfully into a non-functional mechanical bileaflet aortic prosthesis after fracturing the carbon discs while the brain is protected by a filter system. Critical steps of the procedure were identified. This new therapeutic approach might be offered to a limited patient cohort who is not eligible for a surgical redo.

Effects of tubing degradation and pump position on extracorporeal circulation performance.

Extracorporeal circulation (ECC) is an integral part of cardiac surgery. Yet, the contact with artificial surfaces, mechanical stress, shear, and suction forces within the ECC pose a pronounced risk for damaging the corpuscular components of the blood. These suction forces may be reduced by a repositioning of the roller pumps employed below the reservoir. Furthermore, the repeated compression of the involved silicone tubing is likely to cause degradation. We present our observations regarding changes in the ECC performance following this degradation process. In vitro experiments were performed in a standard as well as a simplified ECC setup and included measurements of pressure, effective flow, and tubing restoring force over a time frame of 12 hours with two different pump positions utilizing transit time flow measurement. Suction forces within the tubing could be significantly reduced by shifting the pump position below the reservoir. Regardless of the setup, the tubing showed significant loss of restoring force as well as effective flow over time. A shift of the pump position within the ECC setup can be recommended to prevent blood damaging negative pressures. Further research is necessary to evaluate the exact cause of the reduction of restoring force overtime as well as its risks for the patients. Finally, our results underline the importance of transit time flow measurements to collect reliable flow data.