Translating Imaging Into 3D Printed Cardiovascular Phantoms: A Systematic Review of Applications, Technologies, and Validation.

Translation of imaging into 3-dimensional (3D) printed patient-specific phantoms (3DPSPs) can help visualize complex cardiovascular anatomy and enable tailoring of therapy. The aim of this paper is to review the entire process of phantom production, including imaging, materials, 3D printing technologies, and the validation of 3DPSPs. A systematic review of published research was conducted using Embase and MEDLINE, including studies that investigated 3DPSPs in cardiovascular medicine. Among 2,534 screened papers, 212 fulfilled inclusion criteria and described 3DPSPs as a valuable adjunct for planning and guiding interventions (n = 108 [51%]), simulation of physiological or pathological conditions (n = 19 [9%]), teaching of health care professionals (n = 23 [11%]), patient education (n = 3 [1.4%]), outcome prediction (n = 6 [2.8%]), or other purposes (n = 53 [25%]). The most common imaging modalities to enable 3D printing were cardiac computed tomography (n = 131 [61.8%]) and cardiac magnetic resonance (n = 26 [12.3%]). The printing process was conducted mostly by material jetting (n = 54 [25.5%]) or stereolithography (n = 43 [20.3%]). The 10 largest studies that evaluated the geometric accuracy of 3DPSPs described a mean bias <±1 mm; however, the validation process was very heterogeneous among the studies. Three-dimensional printed patient-specific phantoms are highly accurate, used for teaching, and applied to guide cardiovascular therapy. Systematic comparison of imaging and printing modalities following a standardized validation process is warranted to allow conclusions on the optimal production process of 3DPSPs in the field of cardiovascular medicine.

Imaging-Based, Patient-Specific Three-Dimensional Printing to Plan, Train, and Guide Cardiovascular Interventions: A Systematic Review and Meta-Analysis.

BACKGROUND: To tailor cardiovascular interventions, the use of three-dimensional (3D), patient-specific phantoms (3DPSP) encompasses patient education, training, simulation, procedure planning, and outcome-prediction. AIM: This systematic review and meta-analysis aims to investigate the current and future perspective of 3D printing for cardiovascular interventions. METHODS: We systematically screened articles on Medline and EMBASE reporting the prospective use of 3DPSP in cardiovascular interventions by using combined search terms. Studies that compared intervention time depending on 3DPSP utilisation were included into a meta-analysis. RESULTS: We identified 107 studies that prospectively investigated a total of 814 3DPSP in cardiovascular interventions. Most common settings were congenital heart disease (CHD) (38 articles, 6 comparative studies), left atrial appendage (LAA) occlusion (11 articles, 5 comparative, 1 randomised controlled trial [RCT]), and aortic disease (10 articles). All authors described 3DPSP as helpful in assessing complex anatomic conditions, whereas poor tissue mimicry and the non-consideration of physiological properties were cited as limitations. Compared to controls, meta-analysis of six studies showed a significant reduction of intervention time in LAA occlusion (n=3 studies), and surgery due to CHD (n=3) if 3DPSPs were used (Cohen's d=0.54; 95% confidence interval 0.13 to 0.95; p=0.001), however heterogeneity across studies should be taken into account. CONCLUSIONS: 3DPSP are helpful to plan, train, and guide interventions in patients with complex cardiovascular anatomy. Benefits for patients include reduced intervention time with the potential for lower radiation exposure and shorter mechanical ventilation times. More evidence and RCTs including clinical endpoints are needed to warrant adoption of 3DPSP into routine clinical practice.

Early Experience With a Novel Suture Device for Sternal Closure in Pediatric Cardiac Surgery.

BACKGROUND: Sternal closure by absorbable suture material is an established method for chest closure in pediatric cardiac surgical procedures. However, the formation of granuloma around knotted suture material is frequently observed and has potential for prolonged wound healing and infection, particularly in newborns and infants. This retrospective study analyzed the suitability and reliability of a novel absorbable, self-locking, multianchor knotless suture with antibacterial technology for sternal closure in pediatric cardiac surgical procedures. METHODS: The applied material (STRATAFIX Symmetric PDS Plus, Ethicon) presents a polydioxanon (PD) suture with a self-locking, multianchor design that enables a sternal closure in a continuous knotless suture technique. All children undergoing knotless closure after standard median sternotomy were examined for the occurrence of sternal wound infection or sternal instability by applying the screening criteria of the Centers for Disease Control and Prevention at hospital discharge and at 30 and 60 days. RESULTS: The new knotless sternal closure was used in 130 patients. Patients were a mean age of 19.0 ± 31.9 months (range, 0-142 months), and mean bodyweight was 7.8 ± 6.6 kg (range, 2.4-35 kg). Delayed sternal closure occurred in 23 patients, with a mean closure time after 2.9 ± 2.6 days. One superficial incisional sternal site infection occurred, but no cases of deep sternal site infection or sternal instability were observed. CONCLUSIONS: The application of the absorbable, knotless suture technique provides excellent results regarding the rate of sternal wound infection and improved healing after median sternotomy in pediatric patients.

Multimodality Imaging for Evaluation of Bicaval Valved Stent Implantation in Severe Tricuspid Regurgitation.

Preprocedural planning and postprocedural evaluation after transcatheter treatment of severe tricuspid regurgitation remain challenging and require further research and standardization. We illustrate the use of multimodality imaging techniques in 3 patients undergoing implantation of a novel custom-made bicaval valved stent for symptomatic treatment of severe tricuspid regurgitation. (Level of Difficulty: Advanced.).

Symptomatic Coronary Anomalies and Ischemia in Teenagers - Rare but Real.

Three cases of teenagers with anomalous aortic origin of the coronary arteries (AAOCA) are presented with typical exercise induced symptoms (chest pain, syncope or dizziness). Using multimodal imaging, diagnoses was confirmed showing interarterial and/or intramural course of the coronary artery explaining the ischemia induced symptoms. Successful surgical correction with unroofing of the AAOCA was performed in all three cases with a favorable outcome. Even though AAOCA are rare, some variants may be relevant and potentially life threatening, therefore treating physicians should be aware of correctly diagnosing and treating these individuals.

Evaluation of ventricular septal defects using high pitch computed tomography angiography of the chest in children with complex congenital heart defects below one year of age.

BACKGROUND: Aim of this study was to assess the accuracy of ventricular septal defects (VSD) using high pitch computed tomography angiography (CTA) of the chest in children below 1 year of age, compared to the intraoperative findings and echocardiography. METHODS: Out of 154 patients that underwent Dual-Source CTA of the chest using a high-pitch protocol at low tube voltages (70-80 kV), 55 underwent surgical repair of a VSD (median age 8 days, range 1-348 days). The margins of the VSDs and their relation to the surrounding structures were reproduced by en-face views using multiplanar reformations (MPR). Absolute diameter, normalized area and relative area compared to the aortic valve annulus were used for discrimination between restrictive and non-restrictive defects. Localization was classified into four subtypes. The results were compared to two-dimensional echocardiography and intraoperative findings. RESULTS: Median absolute size of VSDs did not differ significantly between CTA-measurements (10.8 mm, range 2.8-18.1 mm) and intraoperative findings (12.0 mm, 3.0-25.0 mm, p = 0.09). Echocardiographic values were significantly lower (9.6 mm, 3.0-18.5 mm, both p < 0.01). The classification of the location and orientation matched the intraoperative situs in 96.4% of all cases using CT and in 87.3% using echocardiography. Echocardiography missed the relation to valves in 11% of all cases. Pre-interventional sensitivity and specificity for detection of a VSD were 97.2/98.9% compared to echocardiography. Median radiation dose was 0.32 mSv (range 0.12-2.00 mSv) and differed significantly between second and third generation Dual-Source CT (0.43 vs. 0.22 mSv, p = 0.003). CONCLUSION: Size and subtype of VSDs can be accurately assessed by CTA of the chest in patients with complex congenital heart defects at a very low radiation dose.

Contrast medium application in pediatric high-pitch cardiovascular CT angiography: manual or power injection?

BACKGROUND: Dual-source CT offers accurate depiction of cardiac structures in children with congenital heart disease. For cardiac CT, optimal enhancement of the cardiovascular structures is essential. There is considerable controversy about the administration of contrast medium (CM) in infants and small children, with either a power injector or a manual (hand) injection. OBJECTIVE: The aim of this study was to compare image quality with power injection of CM (study group) and manual injection (control group). METHODS: Thirty-four patients (study group, 6.8 ± 9.6 months and control group, 4.6 ± 8.9 months, nonrandomized) underwent dual-source CT angiography of the chest using a prospective electrocardiography-triggered high-pitch spiral mode (pitch, 3.4; 80 kV). In the study group (17 patients), a power injector was used, and in the control group (17 patients, historical group), manual CM injection had been performed. To assess image quality, both subjective and objective parameters were evaluated independently by 2 experienced radiologists. RESULTS: Subjective overall image quality, signal-to-noise ratio, and contrast-to-noise ratio were significantly higher using power injection compared with manual injection (P < .05). However, depiction of cardiovascular structures did not differ significantly between both groups in all evaluated regions except the superior vena cava and the coronary arteries. CONCLUSION: In infants and small children with congenital heart disease, both manual and power injector protocols allowed for diagnostic imaging of cardiac and extracardiac structures. However, image quality and vascular attenuation were superior using a power injector.

Dual source computed tomography in patients with congenital heart disease.

OBJECTIVES: The objective of this study was to review our early experience with the dual source computed tomography (DSCT), a recently available scanner technique equipped with two X-ray tubes and two detectors, in the context of congenital cardiac malformations. PATIENTS AND METHODS: We reviewed 40 pediatric patients with congenital heart disease (CHD) who underwent DSCT between September 2009 and December 2011 as diagnostic imaging tool for surgical procedures. RESULTS: The median age was 0.36 years (range: 3 days to 44 years). Great vessels (n = 13), cardiac anatomy (n = 13), trachea and vascular rings (n = 7), pulmonary veins (n = 4), and coronary arteries (n = 3) were focused on, which revealed important information for surgery. Scanning quality was affected in only two cases (metal artifacts and tachycardia). Overall median age-specific dose was 1.47 mSv. In patients younger than 1 year (n = 26), median dose was 1.28 mSv. CONCLUSION: DSCT allows a very rapid scan speed, examinations are performed in spontaneously breathing patients, and the radiation exposure is relatively low. It is very valuable in the setting of complex surgery by revealing the position of anatomical structures in their relation to each other. Missing information can be acquired less invasively in addition to echocardiography and might replace cardiac catheterization for several morphological indications.

Hybrid pulmonary valve implantation: injection of a self-expanding tissue valve through the main pulmonary artery.

An 8-year-old (35 kg) boy presented with progressive right ventricular outflow tract enlargement (28 mm) and progressive tricuspid regurgitation after transannular repair of tetralogy of Fallot and was scheduled for pulmonary valve replacement. To spare reoperation on full sternotomy, a transverse mini-thoracotomy through the third intercostal space was used to implant an injectable 29-mm stented porcine valve directly through an incision of the pulmonary artery bifurcation. The procedure was performed while rapid ventricular pacing and right ventricular unload by a short running femorally implanted cardiopulmonary bypass. The stented valve was fixed with three single sutures to avoid embolization. The interventional result was well with full competence of the valve. The boy was discharged at day 4 after the procedure.