Establishing 3D Printing at the Point of Care: Basic Principles and Tools for Success.

As the medical applications of three-dimensional (3D) printing increase, so does the number of health care organizations in which adoption or expansion of 3D printing facilities is under consideration. With recent advancements in 3D printing technology, medical practitioners have embraced this powerful tool to help them to deliver high-quality patient care, with a focus on sustainability. The use of 3D printing in the hospital or clinic at the point of care (POC) has profound potential, but its adoption is not without unanticipated challenges and considerations. The authors provide the basic principles and considerations for building the infrastructure to support 3D printing inside the hospital. This process includes building a business case; determining the requirements for facilities, space, and staff; designing a digital workflow; and considering how electronic health records may have a role in the future. The authors also discuss the supported applications and benefits of medical 3D printing and briefly highlight quality and regulatory considerations. The information presented is meant to be a practical guide to assist radiology departments in exploring the possibilities of POC 3D printing and expanding it from a niche application to a fixture of clinical care. An invited commentary by Ballard is available online. ©RSNA, 2022.

Distribution of C-arm projections in native and bioprosthetic aortic valves cusps: Implication for BASILICA procedures.

OBJECTIVES: We sought to document aortic cusps fluoroscopic projections and their distributions using leaflet alignment which is a novel concept to optimize visualization of leaflets and for guiding BASILICA (bioprosthetic or native aortic scallop intentional laceration to prevent coronary artery obstruction) and determine whether these projections were feasible in catheter laboratory. BACKGROUND: Optimal fluoroscopic projections of aortic valve cusps have not been well described. METHODS: A total of 128 pre-transcatheter aortic valve replacement (pre-TAVR) computed tomographies (CT) (72 native valves and 56 bioprosthetic surgical valves) were analyzed. Using CT software (3Mensio, Pie medical imaging, the Netherlands), leaflet alignment was performed and the feasibility of these angles, which were defined as rate of obtainable with efforts (within LAO/RAO of 85° and CRA/CAU of 50°) were evaluated. RESULTS: High feasibility was seen in right coronary cusp (RCC) front view (100%) and left coronary cusp (LCC) side view (99.2%), followed by noncoronary cusp side view (95.3%). In contrast, low feasibility of RCC side view (7.8%) and LCC front view (47.6%) was observed. No statistical differences were seen between the distribution of native valves and bioprosthetic surgical valves. With patient/table tilt of 20°LAO and 10°CRA, the feasibility of RCC side view and LCC front view increased to 43.7 and 85.2%, respectively. CONCLUSION: Distributions of each cusp's leaflet alignment follows "sigmoid curve" which can provide better understanding of aortic valve cusp orientation in TAVR and BASILICA. RCC side view used in right cusp BASILICA is commonly unachievable in catheter laboratory and may improve with patient/table tilt.

Establishing Quality and Safety in Hospital-based 3D Printing Programs: Patient-first Approach.

The adoption of three-dimensional (3D) printing is rapidly spreading across hospitals, and the complexity of 3D-printed models and devices is growing. While exciting, the rapid growth and increasing complexity also put patients at increased risk for potential errors and decreased quality of the final product. More than ever, a strong quality management system (QMS) must be in place to identify potential errors, mitigate those errors, and continually enhance the quality of the product that is delivered to patients. The continuous repetition of the traditional processes of care, without insight into the positive or negative impact, is ultimately detrimental to the delivery of patient care. Repetitive tasks within a process can be measured, refined, and improved and translate into high levels of quality, and the same is true within the 3D printing process. The authors share their own experiences and growing pains in building a QMS into their 3D printing processes. They highlight errors encountered along the way, how they were addressed, and how they have strived to improve consistency, facilitate communication, and replicate successes. They also describe the vital intersection of health care providers, regulatory groups, and traditional manufacturers, who contribute essential elements to a common goal of providing quality and safety to patients. ©RSNA, 2021.

Contemporary Transcatheter Mitral Valve Replacement for Mitral Annular Calcification or Ring.

OBJECTIVES: The aim of this study was to evaluate outcomes of commercial transcatheter mitral valve replacement (TMVR) for annular rings and calcification using contemporary techniques. BACKGROUND: TMVR is evolving in the absence of other viable treatment options for severe mitral annular calcification and failing ring repairs. The concomitant use of laceration of the anterior mitral valve leaflet to prevent left ventricular outflow tract obstruction and pre-emptive alcohol septal ablation is not well studied in clinical practice. METHODS: A single-center study was conducted of valve-in-mitral annular calcification (ViMAC) and valve-in-ring (ViRing) TMVR from September 2015 to April 2020. In-hospital and 30-day outcomes were assessed. RESULTS: Forty patients underwent TMVR (28 ViMAC and 12 ViRing). Sixteen ViMAC (57%) and 5 ViRing (42%) patients underwent attempted laceration of the anterior mitral valve leaflet to prevent left ventricular outflow tract obstruction. Three patients underwent pre-emptive alcohol septal ablation. The median index hospitalization was 7 days. Six patients died within 30 days of the procedure, 6 (21%) in the ViMAC group and none in the ViRing group. Five patients (13%) had left ventricular outflow tract obstruction: 4 (14%) in the ViMAC cohort and 1 (8%) in the ViRing cohort. Five patients (13%) had either intraprocedural valve embolization or late migration (4 ViMAC and 1 ViRing). Technical success defined according to Mitral Valve Academic Research Consortium criteria was present in 25 patients (63%): 9 (75%) in the ViRing cohort and 16 (57%) in the ViMAC cohort. At 30 days, the mitral valve gradient was significantly reduced (5.5 ± 2.1 vs. 10.6 ± 4.8; p < 0.01). Three patients (8%) had at least moderate residual mitral regurgitation. CONCLUSIONS: Transcatheter ViMAC and ViRing can be successfully performed but frequently require the use of contemporary adjunctive techniques.

Coronary ostial eccentricity in severe aortic stenosis: Guidance for BASILICA transcatheter leaflet laceration.

BACKGROUND: Eccentricity of coronary ostial positions in relation to the aortic valve cusp may influence the target laceration location in BASILICA (Bioprosthetic or native Aortic Scallop Intentional Laceration to prevent Coronary Artery obstruction). Eccentricity of the coronary ostia in relation to coronary cusps of native and valve-in-valve transcatheter aortic valve replacement (TAVR) was not well described before. METHODS: A total of 121 pre-TAVR patients' CT data (72 native valves TAVR and 49 bioprosthetic surgical valves TAVR) was included and coronary ostial eccentricity angles were measured and compared. Coronary ostial angles were measured between mid-cusp line to coronary ostium in CT perpendicular images. RESULTS: In the overall cohort, the right coronary artery (RCA) had an eccentric origin in the majority of cases, favoring the commissure between the right and the non coronary cusp (17.0°, IQR; 10-25). On the other hand, the left coronary artery (LCA) originated most commonly near center of the cusp position (0°, IQR; -8 -7.5) In comparison of native and bioprosthetic valves, RCA ostial angles were more eccentric in native valves (19.0°, IQR; 12-26) than in bioprosthetic valves (14.0°, IQR; 3-20) (p = 0.004). Whereas, LCA ostial angle has no significant differences between native valves (-2.0°, IQR;-7.75-5.75) and bioprosthetic valves (1°, IQR;-8-13), (p = 0.6). CONCLUSION: RCA ostia often have an eccentric origin towards the non-coronary cusp, especially in native aortic valves, while LCA ostia commonly originate near the center of the cusp. This finding may contribute to better performance of BASILICA procedures.

Intact and Isolated Human Cadaveric Coronary Artery Perfusion Models to Facilitate Research and Education Regarding Coronary Anatomy and Pathology.

Cadaveric tissue-perfusion models are well established in the fields of structural heart and peripheral vascular disease; however, less consideration has been given toward coronary artery disease despite comparable prevalence and morbidity. Two tissue-perfusion models were developed to address this need. The first, an intact heart model, allows simulation of percutaneous coronary interventional procedures. The second focuses upon isolated arteries, allowing quantification of simulated procedures. Both models were applied for clinical training and for investigations into medical device behavior. The manner of preparation facilitates access to clinically relevant disease, thus providing a platform to further research on coronary artery disease.

Anatomy and Function of the Normal and Diseased Mitral Apparatus: Implications for Transcatheter Therapy.

Transcatheter mitral valve therapy requires an in-depth understanding of the mitral valve apparatus (annulus, leaflets, chordae tendinae, and papillary muscles) and the impact of various disease states. Adjacent structures (left atrium, left ventricular outflow tract, aortic valve, coronary sinus, and circumflex artery) must also be respected. This article reviews the anatomy and function of the normal and diseased mitral valve apparatus and the implications for catheter-based intervention.