Mario Montealegre-Gallegos

Three-Dimensional Printing of Mitral Valve Using Echocardiographic Data

Three-dimensional (3D) printing has steadily gained traction as a clinical tool. Current applications include developing patient-specific implants, prostheses, and realistic anatomic models for surgical education and planning [(1,2)][1]. In cardiac surgery, patient-specific 3D models of hearts with

Perioperative Ultrasound Training in Anesthesiology: A Call to Action.

The purpose of this position paper is to define the scope of perioperative ultrasound (US), review the current status of US training practices during anesthesiology residency, and suggest the recommendations for current and future trainees on how to obtain perioperative US proficiency. We define per

Echocardiography derived three-dimensional printing of normal and abnormal mitral annuli

AIMS AND OBJECTIVES The objective of this study was to assess the clinical feasibility of using echocardiographic data to generate three-dimensional models of normal and pathologic mitral valve annuli before and after repair procedures. MATERIALS AND METHODS High-resolution transesophageal echocardiographic data from five patients was analyzed to delineate and track the mitral annulus (MA) using Tom Tec Image-Arena software. Coordinates representing the annulus were imported into Solidworks software for constructing solid models. These solid models were converted to stereolithographic (STL) file format and three-dimensionally printed by a commercially available Maker Bot Replicator 2 three-dimensional printer. Total time from image acquisition to printing was approximately 30 min. RESULTS Models created were highly reflective of known geometry, shape and size of normal and pathologic mitral annuli. Post-repair models also closely resembled shapes of the rings they were implanted with. Compared to echocardiographic images of annuli seen on a computer screen, physical models were able to convey clinical information more comprehensively, making them helpful in appreciating pathology, as well as post-repair changes. CONCLUSIONS Three-dimensional printing of the MA is possible and clinically feasible using routinely obtained echocardiographic images. Given the short turn-around time and the lack of need for additional imaging, a technique we describe here has the potential for rapid integration into clinical practice to assist with surgical education, planning and decision-making.

Combined Epidural-General Anesthesia vs General Anesthesia Alone for Elective Abdominal Aortic Aneurysm Repair

Importance Epidural analgesia (EA) is used as an adjunct procedure for postoperative pain control during elective abdominal aortic aneurysm (AAA) surgery. In addition to analgesia, modulatory effects of EA on spinal sympathetic outflow result in improved organ perfusion with reduced complications. Reductions in postoperative complications lead to shorter convalescence and possibly improved 30-day survival. However, the effect of EA on long-term survival when used as an adjunct to general anesthesia (GA) during elective AAA surgery is unknown. Objective To evaluate the association between combined EA-GA vs GA alone and long-term survival and postoperative complications in patients undergoing elective, open AAA repair. Design, Setting, and Participants A retrospective analysis of prospectively collected data was performed. Patients undergoing elective AAA repair between January 1, 2003, and December 31, 2011, were identified within the Vascular Society Group of New England (VSGNE) database. Kaplan-Meier curves were used to estimate survival. Cox proportional hazards regression models and multivariable logistic regression models assessed the independent association of EA-GA use with postoperative mortality and morbidity, respectively. Data analysis was conducted from March 15, 2015, to September 2, 2015. Interventions Combined EA-GA. Main Outcomes and Measures The primary outcome measure was all-cause mortality. Secondary end points included postoperative bowel ischemia, respiratory complications, myocardial infarction, dialysis requirement, wound complications, and need for surgical reintervention within 30 days of surgery. Results A total of 1540 patients underwent elective AAA repair during the study period. Of these, 410 patients (26.6%) were women and the median (interquartile range) age was 71 (64-76) years; 980 individuals (63.6%) received EA-GA. Patients in the 2 groups were comparable in terms of age, comorbidities, and suprarenal clamp location. At 5 years, the Kaplan-Meier-estimated overall survival rates were 74% (95% CI, 72%-76%) and 65% (95% CI, 62%-68%) in the EA-GA and GA-alone groups, respectively (P < .01). In adjusted analyses, EA-GA use was associated with significantly lower hazards of mortality compared with GA alone (hazard ratio, 0.73; 95% CI, 0.57-0.92; P = .01). Patients receiving EA-GA also had lower odds of 30-day surgical reintervention (odds ratio [OR], 0.65; 95% CI, 0.44-0.94; P = .02) as well as postoperative bowel ischemia (OR, 0.54; 95% CI, 0.31-0.94; P = .03), pulmonary complications (OR, 0.62; 95% CI, 0.41-0.95; P = .03), and dialysis requirements (OR, 0.44; 95% CI, 0.23-0.88; P = .02). No significant differences were noted for the odds of wound (OR, 0.88; 95% CI, 0.38-1.44; P = .51) and cardiac (OR, 1.08; 95% CI, 0.59-1.78; P = .82) complications. Conclusions and Relevance Combined EA-GA was associated with improved survival and significantly lower HRs and ORs for mortality and morbidity in patients undergoing elective AAA repair. The survival benefit may be attributable to reduced immediate postoperative adverse events. Based on these findings, EA-GA should be strongly considered in suitable patients.

Cardiac Output Calculation and Three-Dimensional Echocardiography

OBJECTIVE To compare the determination of stroke volume (SV) and cardiac output (CO) using 2-dimensional (2D) versus 3-dimensional (3D) transesophageal echocardiography (TEE). DESIGN Prospective observational study. SETTING Tertiary care university hospital. PARTICIPANTS 35 patients without structural valve abnormalities undergoing isolated coronary artery bypass grafting. INTERVENTIONS Left ventricular outflow tract (LVOT) diameter determined with 2D TEE was used to estimate LVOT cross-sectional area (CSALVOT). LVOT area was measured directly with 3D TEE by planimetry on an en face view. SV and CO were calculated for both methods using the continuity equation. MEASUREMENTS AND MAIN RESULTS The area of the LVOT differed significantly between methods, being significantly larger in the 3D method (3.57±0.70 cm(2)v 3.98±0.93 cm(2)) . This resulted in a 10% lower CO with the 2D method of LVOT area estimation. CONCLUSIONS LVOT area is underestimated with the single- axis 2D method when compared with 3D planimetered area. This results in a CO that is approximately 10% lower with the 2D method.

Manual Skill Acquisition During Transesophageal Echocardiography Simulator Training of Cardiology Fellows: A Kinematic Assessment

OBJECTIVE To investigate whether a transesophageal echocardiography (TEE) simulator with motion analysis can be used to impart proficiency in TEE in an integrated curriculum-based model. DESIGN A prospective cohort study. SETTING A tertiary-care university hospital. PARTICIPANTS TEE-naïve cardiology fellows. INTERVENTIONS Participants underwent an 8-session multimodal TEE training program. Manual skills were assessed at the end of sessions 2 and 8 using motion analysis of the TEE simulators probe. At the end of the course, participants performed an intraoperative TEE; their examinations were video captured, and a blinded investigator evaluated the total time and image transitions needed for each view. Results are reported as mean±standard deviation, or median (interquartile range) where appropriate. MEASUREMENTS AND MAIN RESULTS Eleven fellows completed the knowledge and kinematic portions of the study. Five participants were excluded from the evaluation in the clinical setting because of interim exposure to TEE or having participated in a TEE rotation after the training course. An increase of 12.95% in post-test knowledge scores was observed. From the start to the end of the course, there was a significant reduction (p<0.001 for all) in the number of probe. During clinical performance evaluation, trainees were able to obtain all the required echocardiographic views unassisted but required a longer time and had more probe transitions when compared with an expert. CONCLUSION A curriculum-based approach to TEE training for cardiology fellows can be complemented with kinematic analyses to objectify acquisition of manual skills during simulator-based training.

Three-Dimensional Printing of the Mitral Annulus Using Echocardiographic Data: Science Fiction or in the Operating Room Next Door?

Address reprint requests to Feroze Mahmood, MD. Beth Israel Deaconess Medical Center One Deaconess Road, CC-470, Boston, MA 02215. E-mail: hwarraic@bidmc.harvard.edu

Hemodynamic Testing of Patient-Specific Mitral Valves Using a Pulse Duplicator: A Clinical Application of Three-Dimensional Printing

OBJECTIVE To evaluate the feasibility of obtaining hemodynamic metrics of echocardiographically derived 3-dimensional printed mitral valve models deployed in a pulse-duplicator chamber. DESIGN Exploratory study. SETTING Tertiary-care university hospital. PARTICIPANTS Percutaneous MitraClip procedure patient. INTERVENTIONS Three-dimensional R-wave gated, full-volume transesophageal echocardiography images were obtained after deployment of the MitraClip device. A high-quality diastolic frame of the mitral valve was segmented using Mimics Innovation Suite and merged with a flange. The data were exported as a stereolithography (.stl) file, and a rigid 3-dimensional model was printed using a MakerBot Replicator 2 printer. A flexible silicone cast then was created and deployed in the pulse-duplicator chamber filled with a blood-mimicking fluid. MEASUREMENTS AND MAIN RESULTS The authors were able to obtain continuous-wave Doppler tracings of the valve inflow with a transesophageal echocardiography transducer. They also were able to generate diastolic ventricular and atrial pressure tracings. Pressure half-time and mitral valve area were computed from these measurements. CONCLUSION This pulse duplicator shows promising applications in hemodynamic testing of patient-specific anatomy. Future modifications to the system may allow for visualization and data collection of gradients across the aortic valve.

Multimodal Perioperative Ultrasound Course for Interns Allows for Enhanced Acquisition and Retention of Skills and Knowledge.

The ability to apply perioperative ultrasound techniques is a desirable skill for clinicians. We implemented a multimodal 13-day basic ultrasound course for 6 anesthesia interns. Their scores on a knowledge test increased after the course and were sustained and similar to those of 6 senior residents 90 days later. The interns acquired images of the heart in volunteers with little assistance after the course. They maintained their ability to acquire echocardiographic images on a simulator 90 days later with kinematic measures superior to the same seniors. Through this course, interns gained knowledge and skills equal to or greater than seniors.

Tricuspid Annulus: A Three-Dimensional Deconstruction and Reconstruction

BACKGROUND Before clinical manifestation of regurgitation, the tricuspid annulus dilates and flattens when right ventricular dysfunction is potentially reversible. That makes the case for a prophylactic tricuspid annuloplasty even in the absence of significant tricuspid regurgitation. Owing to the appreciation of the favorable prognostic value of tricuspid annuloplasty, the geometry of the normal tricuspid annulus merits critical analysis. METHODS Three-dimensional transesophageal echocardiographic data from 26 patients were analyzed using Image Arena (TomTec, Munich, Germany) software. Cartesian coordinate data from tricuspid annuli were exported to MATLAB (Mathworks, Natick, MA) for further processing. Annular metrics related to size, shape, and motion were computed. RESULTS The tricuspid annulus demonstrated significant changes in area (p<0.01) and perimeter (p<0.03) during the cardiac cycle, with maximum values attained at end diastole. There was significant correlation between two- and three-dimensional area changes, indicating true expansion in the annulus. The anterolateral region of the annulus demonstrated the greatest dynamism (p<0.01), and the anteroseptal region showed the least. The anteroseptal region also displayed the most nonplanarity in the annulus. In addition, vertical translational motion was observed, with a mean distance of 11.3±3.7 mm between end systolic and end diastolic annular centroids. CONCLUSIONS The tricuspid annulus is a dynamic, multiplanar structure with heterogeneous regional behavior. These characteristics should be taken into account for optimal annuloplasty device design and efficacy.