Real-Time Multiplanar Reconstruction Imaging Using 3-Dimensional Transesophageal Echocardiography in Structural Heart Interventions.

The complexity of structural heart interventions has led to a demand for sophisticated periprocedural imaging guidance. Although traditional 2-dimensional (2D) transesophageal techniques are used widely, new-generation 3D ultrasound probes enable high temporal and spatial resolution. Multiplanar reconstruction of acquired 3D datasets has gained considerable momentum for precise imaging and to increase the validity of measurements. Previously, this technique was used after the acquisition of suitable 3D datasets. Recent advances in technology have enabled the use of live mode for multiplanar reconstruction across different ultrasound vendor platforms. The use of live multiplanar reconstruction can enhance the precision in real-time imaging, enable simultaneous visualization of structures of interest in multiple planes, reduce the need for probe manipulation, and thereby contribute to the success of the procedures. In this narrative review, the authors describe the rationale and utility for 3D transesophageal live multiplanar reconstruction, and outline its use for the structural heart interventions of mitral and tricuspid valve edge-to-edge repair, left atrial appendage occlusion, and the Lampoon procedure. A 3D transesophageal echocardiogram with live-multiplanar reconstruction has the potential to advance guidance of these complex interventions.

The Association Between Hypophosphatemia and Lactic Acidosis After Cardiac Surgery With Cardiopulmonary Bypass: A Retrospective Cohort Study.

OBJECTIVES: The clinical significance of hypophosphatemia in cardiac surgery has not been investigated extensively. The aim of this study was to evaluate the association of postoperative hypophosphatemia and lactic acidosis in cardiac surgery patients at the time of intensive care unit (ICU) admission. DESIGN: A retrospective cohort study. SETTING: At a single academic center. PARTICIPANTS: Patients who underwent nontransplant cardiac surgery with cardiopulmonary bypass between August 2009 and December 2020. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Serum phosphate and lactate levels were measured upon ICU admission in patients undergoing nontransplant cardiac surgery with cardiopulmonary bypass. There were 681 patients in the low-phosphate (<2.5 mg/dL) group and 2,579 patients in the normal phosphate group (2.5-4.5 mg/dL). A higher proportion of patients in the low phosphate group (26%; 179 of 681; 95% CI: 23-30) had severe lactic acidosis compared to patients in the normal phosphate group (16%; 417 of 2,579; 95% CI: 15-18). In an unadjusted logistic regression model, patients in the low phosphate group had 1.9-times the odds of having severe lactic acidosis (serum lactate ≥4.0 mmol/L) when compared to patients in the normal phosphate group (95% CI: 1.5-2.3), and still 1.4-times the odds (95% CI: 1.1-1.7) after adjusting for several possible confounders. CONCLUSIONS: Hypophosphatemia is associated with lactic acidosis in the immediate postoperative period in cardiac surgery patients. Future studies will need to investigate it as a potential treatment target for lactic acidosis.

Initial experience with the fourth generation MitraClip™: Outcomes, procedural aspects, and considerations for device selection.

OBJECTIVES: We present our initial experience with the fourth-generation MitraClip™ (G4) system and propose preliminary criteria for device selection. BACKGROUND: The MitraClip™ G4 system recently underwent a "controlled release" for transcatheter edge-to-edge mitral valve repair. The four new devices include technical improvements such as controlled gripper actuation (independent leaflet capture) and continuous left atrial pressure monitoring. To date, a patient-specific device selection algorithm, and the technology's impact on procedural times and success, have not been described. METHODS: We present an initial multi-center experience and short-term outcomes with the new system, suggest procedural and imaging considerations, and propose initial guidance for device selection. RESULTS: Sixty-one procedures performed by three operators at two centers between November 2019 and May 2020 were analyzed. At 30-day follow-up, there were three deaths (4.9%), four neurological events (6.6%), and seven re-hospitalizations (11.5%). Fifty-nine patients achieved device and procedural success (96.7%), and there was one device-related technical issue (1.6%). Compared to the same operators utilizing the third generation MitraClip™, the G4 system resulted in a significant reduction in the median number of clips used per patient (1 IQR 1-2 vs. 2 IQR 1-3, p = .023) and a trend toward shorter device times. CONCLUSION: Based on our initial experience, we found that the MitraClip™ G4 system is associated with high procedural success and fewer devices needed per procedure. The expanded device options may allow a more targeted approach to the myriad of pathologic presentations of mitral regurgitation. This early experience should provide a foundational opportunity for further refinement.

Novel Transcatheter Approach to Treat Primum Atrial Septal Defects.

•Degenerative common AVC defect can mimic rheumatic MV stenosis.•Closure of primum ASD can be achieved percutaneously.•Live 3D multiplanar TEE is crucial for procedural guidance.

The transforming growth factor-beta type III receptor mediates distinct subcellular trafficking and downstream signaling of activin-like kinase (ALK)3 and ALK6 receptors.

Bone morphogenetic proteins (BMPs) signal through the BMP type I and type II receptors to regulate cellular processes, including embryonic development. The type I BMP receptors activin-like kinase (ALK)3 and ALK6 share a high degree of homology, yet possess distinct signaling roles. Here, we report that although the transforming growth factor (TGF)-beta type III receptor (TbetaRIII) enhanced both ALK3 and ALK6 signaling, TbetaRIII more potently enhanced ALK6-mediated stimulation of the BMP-responsive promoters XVent2 and 3GC2, and up-regulation of the early response gene Smad6. In contrast, TbetaRIII specifically enhanced ALK3-mediated up-regulation of the early response gene ID-1. TbetaRIII associated with ALK3 primarily through their extracellular domains, whereas its interaction with ALK6 required both the extracellular and cytoplasmic domains. TbetaRIII, along with its interacting scaffolding protein beta-arrestin2, induced the internalization of ALK6. In contrast, TbetaRIII colocalized with and resulted in the cell surface retention of ALK3, independently of beta-arrestin2. Although complex formation between TbetaRIII, ALK6, and beta-arrestin2 and TbetaRIII/ALK6 internalization resulted in maximal BMP signaling, the TbetaRIII mutant unable to interact with beta-arrestin2, TbetaRIII-T841A, was unable to do so. These studies support a novel role for TbetaRIII in mediating differential ALK3 and ALK6 subcellular trafficking resulting in distinct signaling downstream of ALK3 and ALK6.