Comparison of artery diameters in the Aachen minipig serving as a human intracranial in vivo model.

Minipigs are used as in vivo endovascular models, particularly in stroke and aneurysm research. However, detailed knowledge of the diameters of forelimb arteries that are commonly used as surrogates for human brain-supplying arteries are lacking. This study aimed to determine the diameters of forelimb and neck arteries in Aachen minipigs and to compare those to the diameters of human cerebral brain-supplying arteries in order to assess the validity of the Aachen minipig as a human intracranial in vivo model. We measured the diameters in the external carotid artery and eight different branches of the subclavian artery in 12 Aachen minipigs using angiographic imaging. Analysed arteries comprised the external carotid artery, axillary artery, brachial artery, subscapular artery first segment, subscapular artery second segment, external thoracic artery, caudal circumflex humeral artery, suprascapular artery and thoracodorsal artery. We compared these diameters to diameters of the following human brain-supplying arteries: terminal internal carotid artery (carotid-T and petrous segment), M1 segment of the middle cerebral artery, M2 segments of the middle cerebral artery, anterior cerebral artery, vertebral artery and basilar artery. Median diameters of porcine forelimb arteries ranged from 1.8 to 4.9 mm, and human brain supplying arteries ranged in diameter from 1.4 to 4.3 mm. Depending on the intended use, this allows porcine forelimb arteries to be selected which are statistically comparable to human brain-supplying vessels. In conclusion, we identified several equivalent arteries of the porcine subclavian branches that are comparable to human brain-supplying arteries. This may help to validate the minipig as a suitable in vivo model for neurovascular experiments.

Flow control in the middle cerebral artery during thrombectomy: the effect of anatomy, catheter size and tip location.

BACKGROUND: Catheter size, location and circle of Willis anatomy impact the flow conditions during interventional stroke therapy. The aim of the study was to systematically investigate the influence of these factors on flow control in the middle cerebral artery by means of a computational model based on 100 patients with stroke who received endovascular treatment. METHODS: The dimensions of the cervical and intracranial cerebral arteries of 100 patients who received endovascular mechanical thrombectomy for acute ischemic stroke were measured and a three-dimensional model of the circle of Willis was created based on these data. Flow control in the middle cerebral artery with variations in catheter size, catheter location and configurations of collateral vessels was determined using a computational model. A total of 48 scenarios were analyzed. RESULTS: Flow reversal with a distal aspiration catheter alone was not possible in the internal carotid artery and only sometimes possible in the middle cerebral artery (14 of 48 cases). The Catalyst 7 catheter was more often successful in achieving flow reversal than Catalyst 5 or 6 catheters (p<0.001). In a full circle of Willis anatomy, flow reversal was almost never possible. The absence of one or more communicating arteries significantly influenced flow direction compared with the full anatomy with all communicating arteries present (p=0.028). CONCLUSION: Choosing the biggest possible aspiration catheter and locating it in the middle cerebral artery significantly increases the chances of successful flow control. Flow through the collaterals may impair the flow, and circle of Willis anatomy should be considered during aspiration thrombectomy.

Platelet function testing using the Multiplate analyzer after administration of aspirin in Aachen minipigs.

Knowledge of platelet function in pigs and the effectiveness of antiplatelet therapy is important to ensure proper transferability from animal studies to humans. Our aim was to (1) characterize baseline platelet function of Aachen minipigs using the bedside Multiplate analyzer, (2) compare baseline platelet function with Göttingen minipigs, and (3) characterize platelet inhibition within the first 5 minutes after intravenous administration of acetylsalicylic acid (ASA). We characterized the baseline platelet function and hematological parameters in 9 Aachen minipigs. Historical data of 8 unmedicated Göttingen minipigs were used for comparison of baseline values. Platelet inhibition in Aachen minipigs was tested 1-5 minutes after intravenous administration of 500 mg ASA. Multiplate examinations included the following tests: ASPI test (to assess the effect of ASA), adenosine-diphosphate-test (ADP test) and thrombin receptor activating peptide test (TRAP test). Median values and interquartile range (IQR) of the Multiplate baseline tests in Aachen minipigs were as follows: ASPI: 39 U (IQR = 21-71), ADP: 70 U (IQR = 48-73), and TRAP: 8 U (IQR = 6-9), whereas the values in Göttingen minipigs were as follows: ASPI: 70.5 U (IQR = 60-78), ADP: 51 U (IQR = 45-66), and TRAP: 6.5 U (IQR = 4-8). ASPI values of Göttingen minipigs were significantly higher than those of Aachen minipigs (p = 0.046). Intravenous administration of ASA in Aachen minipigs resulted in significant platelet inhibition after 1 minute, which remained stable over a period of 5 minutes (p≤0.038). Aachen minipigs appeared to have a high variance in arachidonic acid-mediated platelet aggregation. In Aachen minipigs, intravenous ASA administration resulted in immediate platelet inhibition.

Seeing faces, when faces can't be seen: Wearing portrait photos has a positive effect on how patients perceive medical staff when face masks have to be worn.

INTRODUCTION: Since the onset of the coronavirus disease 2019 (COVID-19) pandemic, wearing surgical face masks has become mandatory for healthcare staff in many countries when interacting with patients. Recently, it has been shown that wearing face masks impairs social interaction by diminishing a person's ability to read the emotion of their counterparts, an essential prerequisite to respond adequately in social situations. It is easily conceivable that this may have a tangible negative influence on the communication and relationship between patients and healthcare personnel. We therefore investigated whether it has an effect on how patients perceive healthcare professionals when physicians and nursing staff wear portrait photos with their smiling faces in addition to face masks. METHODS: During the study period of 16 days, the medical staff of our Department wore surgical face masks at all times during any kind of interaction with patients. In a pseudorandomized order, all members of our staff additionally affixed their portrait photos to their work clothes on 8 of the 16 days. After completion of their visit, 226 patients were interviewed anonymously in a cross-sectional study design using a questionnaire in which they rated the following three items: friendliness of staff, medical quality of treatment, and how well they felt taken care of during treatment in our Department. RESULTS: On days, on which staff wore photos, mean scores of the questionnaires were significantly higher than on non-photo days (p = 0.013; mean ± standard deviation = 92.8 ± 11.3 vs. 91.0 ± 12.6; median (range) = 97 (98) vs. 96 (76)). When analyzed separately, the increased scores were only significant for the item friendliness of staff (p = 0.009; mean ± standard deviation = 95.8 ± 6.3 vs. 92.2 ± 11.5; median (range) = 98 (39) vs. 97 (54)). CONCLUSION: Our study suggests that the use of portrait photos with smiling faces has a positive effect on how patients perceive healthcare staff.