Construction and Validation of a Benchtop Model for Testing of Mechanical Thrombectomy Devices for Pulmonary Embolism.

PURPOSE: This study aims to define the process of designing and manufacturing 3D printed and glass models of the pulmonary artery (PA) and utilizing them in a test bed for evaluation of devices for mechanical thrombectomy of pulmonary embolism (PE). MATERIALS AND METHODS: Patient derived computed tomography angiography (CTA) images of the PA were digitally converted into a hollowed-out structure and translated into clear 3D printed and glass models. A test bed was created using a peristaltic pump and silicone tubing connected to the models. Human clot analogs were then prepared and injected within the models. Thrombectomy testing was done using clinically used predicates and baseline characteristics of the models were evaluated by independent interventionalists. RESULTS: The mean sizes of the main pulmonary artery (MPA) for the 3D printed model and glass model were 30.4 mm and 29.2 mm, mimicking those of the patient's PA obtained on CTA. Heterogeneous human clot analogs were created with fibrin composition ranging from 60 to 30%. Mechanical thrombectomy was successfully attempted by independent interventionalists. Both the 3D printed, and glass model were appraised as very good for multiple attributes. CONCLUSION: A complete test bed using 3D printed and glass models of the PA with human clot analogs was created for testing of mechanical thrombectomy devices for PE.

Evaluation of absorbable PLA nasal implants in an ovine model.

OBJECTIVE: To examine biocompatibility and absorption profile of a poly (L-lactide-co-D,L-lactide) 70:30 nasal implant. METHODS: In an ovine model, 66 rod-shaped absorbable implants were placed in 11 nasal dorsa. The sheep were sacrificed at 1.5 (N = 3), 6 (N = 3), 12 (N = 3), 18 (N = 1), and 24 months (N = 1). The nasal dorsum was harvested from each animal. Gross and histopathological examinations were performed. RESULTS: There were no postoperative complications, signs of infection, or tissue rejection throughout follow-up time points. Upon sacrifice, no abnormalities were identified during gross pathological examinations. The histology of the implant sites at all time points showed the implants were fully encapsulated through 12 months. The inflammatory reaction to the implants was minimal to mild at 1.5, 6, and 12 months. At 18 months the implant material was in the mass loss phase, being actively absorbed. During this phase, the inflammatory reaction within the fibrous connective tissue capsule reached expected moderate levels. By 24 months, the inflammatory reaction had diminished in most implantation sites and complete absorption of the rod implants was noted at some sites with nodular bundles of mature collagenized fibrous tissue replacing the implant, devoid of an inflammatory infiltrate. CONCLUSION: Biocompatibility of the poly (L-lactide-co-D,L-lactide) 70:30 material was demonstrated when used as a nasal implant in the nasal dorsum ovine model. Absorption of the implant occurred approximately 18 to 24 months postoperatively, and the implant site was replaced with collagenized fibrous tissue. LEVEL OF EVIDENCE: NA.

Double balloon angioplasty for unstentable large-caliber right coronary stenosis.

Despite newer lower-profile stent technologies, placing coronary stents may still remain challenging when vessels are extremely tortuous. We describe a case of a tortuous, very largecaliber right coronary with a near-180 degrees switchback "shepherd's crook" turn, which could not be stented, and for which double balloon angioplasty was successfully performed.

High levels of HDL cholesterol do not predict protection from cardiovascular disease in women.

Elevated levels >or= 60 mg/dL) of high-density lipoprotein cholesterol have been felt to be protective for cardiovascular disease in women. While cardiovascular disease is the leading killer of women in the United States, this is underrecognized, and women's symptoms are often atypical, leading to underdiagnosis. When high-density lipoprotein cholesterol is high, physicians may underestimate a woman's cardiovascular risk. This tendency may have adverse health consequences.

Behavioral training increases local astrocytic metabolic activity but does not alter outcome of mild transient ischemia.

Functional neurological outcome after transient ischemia might be improved by timely therapeutic intervention. To determine if restorative behavioral therapy influences damage, improves task learning, or alters astrocyte metabolic activity after ischemia, rats (food-restricted to 85% of free-feeding weight) were (a) first trained to respond on one of two levers under a fixed-ratio 20 schedule of food presentation (FR20), then (b) subjected to sham manipulation of carotid arteries or 10 min ischemia by four-vessel occlusion, followed by (c) 4 days of operant testing or inactivity, (d) then all rats were tested under a FR20 lever reversal task for 4 weeks, and (e) 3 days after the last behavioral session astrocyte metabolism was assayed by local uptake of [2-14C]acetate. Mild loss of hippocampal neurons occurred in ischemic rats with or without training after ischemia. Glial fibrillary acidic protein-positive astrocytes were present in similar numbers throughout brains of sham control and ischemic rats. Mild ischemia did not impair learning, and no changes in FR20 reversal learning were detected in sham vs. ischemic rats. Net [14C]acetate uptake was unaffected by ischemia but [14C]acetate uptake increased 15-24% (P<0.05; n=12-15/group) in specific structures (caudate, primary motor and sensorimotor cortex, CA1 hippocampus, subcortical white matter) in the pooled groups of rats that had 4 days FR20 testing vs. inactivity before reversal learning. 'Behavioral therapy' (operant testing on the 4 days immediately following either sham manipulation or ischemia) did not alter ischemic outcome, but was associated with higher acetate utilization in regions involved in motor activities.