Defecation Induced by Stimulation of Sacral S2 Spinal Root in Cats

The aim of this study was to determine if stimulation of sacral spinal nerve roots can induce defecation in cats. In anesthetized cats, bipolar hook electrodes were placed on the S1-S3 dorsal and/or ventral roots. Stimulus pulses (1-50 Hz, 0.2 ms) were applied to an individual S1-S3 root to induce proximal/distal colon contractions and defecation. Balloon catheters were inserted into the proximal and distal colon to measure contraction pressure. Glass marbles were inserted into the rectum to demonstrate defecation by videotaping the elimination of marbles. Stimulation of the S2 ventral root at 7 Hz induced significantly (p<0.05) larger contractions (32±9 cmH2O) in both proximal and distal colon than stimulation of the S1 or S3 ventral root. Intermittent (5 times) stimulation (1 minute on and 1 minute off) of both dorsal and ventral S2 roots at 7 Hz produced reproducible colon contractions without fatigue, while continuous stimulation of 5-minute duration caused significant fatigue in colon contractions. Stimulation (7 Hz) of both dorsal and ventral S2 roots together successfully induced defecation that eliminated 1-2 marbles from the rectum. This study indicates the possibility to develop a novel neuromodulation device to restore defecation function after spinal cord injury using a minimally invasive surgical approach to insert a lead electrode via the sacral foramen to stimulate a sacral spinal root.

Abstract 1122‐000092: Safety and Efficacy of Dual Lumen Balloon Catheters for Neurointervention: Systematic Review and Pooled Analysis

Introduction : Dual‐lumen balloon catheters (DLBCs) are used routinely in the endovascular treatment of cerebral vascular malformations and reportedly, they have been noted to present significant advantages compared to single‐lumen catheters (SLCs). We conducted a systematic review and a pooled analysis in order to assess DLBCs’ overall safety and efficacy and complication rates. Methods : In this PROSPERO registered, PRISMA compliant systematic review, we sought to identify all MEDLINE and EMBASE published single‐arm (DLBCs) and double‐arm (DLBCs versus SLCs) cohorts where DLBCs were used for the treatment of cerebral arteriovenous malformations (AVMs) and dural arteriovenous fistulas (dAVFs). A pooled analysis was conducted for the included single‐arm studies. Immediate angiographic outcome, complications related to the catheter, reflux episodes and entrapment were the primary outcomes, summarized in the pooled analysis. Secondary outcomes included mortality and reported navigability. A meta‐analysis of the double‐arm studies summarized the primary outcomes of total procedural time and immediate angiographic outcome. Registration‐URL: https://www.crd.york.ac.uk/prospero/ Unique Identifier: CRD42021269096 Results : Of the 298 records that were screened by title and abstract, 24 underwent full‐text review. Ultimately, 19 studies were included and combined into a pooled analysis. Of the 227 lesions that were treated, complete (100%) nidal occlusion was achieved in 171 (75%; 95% CI: [69.1‐80.7%]), near‐complete (90‐99%) in 18 (8%; [4.9‐12.4%]), partial/incomplete (25‐89%) in 36 (16%; [11.5‐21.4%]) and none (<25%) in 2 (1%; [0.2‐3.5%]). In total, 13 complications related to the catheter were reported (5.73%; [3.2‐9.8%]), 14 reflux events (6%; [1.9‐10.4%]), 2 entrapment events (1%; [0.2‐3.5%]) and 0 deaths (mortality rate 0%; [0‐2.1%]). Based on two independent reviewers, the navigability of the catheter was judged to be reported as “very good” in 4 studies, “subjectively good” in 9, “slightly more difficult than SLCs” in 5 and “significantly more difficult than SLCs” in 1 study. Of the 19 included studies, only two were double‐armed and combined into a meta‐analysis. The mean total procedural time (SD) was 64.9 minutes (37.5) for DLBCs compared to 125.7 (81.8) for SLCs (P<0.0001), while complete nidal occlusion was noted in 39/45 (86.7%; [72.5‐94.5%]) with the DLBCs compared to 17/29 (58.6%; [39.1‐75.9%]) with the SLCs (P = 0.00596), when only dAVFs where combined. The mean total procedural time was 65.5 minutes (39.1) for DLBCs compared to 106.2 (78.3) for SLCs (P = 0.001), while complete nidal occlusion was noted in 46/59 (78%; [65‐87.3%]) with the DLBCs compared to 52/69 (75.3%; [63.3‐84.6%]) with the SLCs (P = 0.726), when both AVMs and dAVFs where combined. Conclusions : DLBCs are safe and effective for the embolization of cerebral AVMs and dAFVs. More importantly, they can achieve faster and potentially superior results compared to SLCs, when used in the appropriate context. A lack of well‐designed controlled comparative studies has been identified in the literature.

A novel paclitaxel coated balloon with increased drug transfer for treatment of complex vascular lesions

Background Drug coated balloons (DCB) with paclitaxel (Ptx) dose of 2–3.5 μg/mm2 balloon surface inhibit restenosis with different effectiveness and duration of success. A clinical dose finding study is not known for any of the currently marketed products. The aim of the present preclinical trial was to investigate a novel DCB coated with 6 μg Ptx/mm2 in a porcine model. Methods and results The current study investigated a DCB with a novel, modified iopromide based matrix with 6 μg Ptx/mm2. Drug transfer to the vessel wall of peripheral arteries was compared with a dose of 3 μg Ptx/mm2 and two fully overlapping DCB with 3 μg Ptx/mm2, each. Ptx concentration in the vessel wall after drug transfer was about twice as high for balloons with 6 μg/mm2 (1957±1472 μg/g) and two overlapping DCB with 3 μg Ptx/mm2, each (1287±619 μg/g) compared to a single balloon with 3 μg Ptx/mm2, (787±738 μg/g), with statistical significant differences for 1x6 μg/mm2 vs. 1x3 μg/mm2 (p = 0.017) but not for 2x3 μg/mm2 vs. 1x3 μg/mm2 (p = 0.184) and 1x6 μg/mm2 vs. 2x3 μg/mm2 (p = 0.178). The proportion of residual Ptx on balloon after treatment was similar for all groups between 6±1% and 10±3% of dose on balloon. Conclusion The dose of 6 μg Ptx/mm2 was successfully as well as reproducibly coated on conventional balloon catheters. Increased Ptx on balloons resulted in increased drug concentration in the vessel wall. A single balloon with 6 μg Ptx/mm2 seems to provide double dose compared to 3 μg Ptx/mm2, facilitates the procedure, and may reduce medico-economic cost compared to the use of two standard DCB.

Temperature-dependent tensile properties of polyamide 12 for the use in percutaneous transluminal coronary angioplasty balloon catheters

Background Percutaneous transluminal coronary angioplasty (PTCA) balloon catheters must withstand high pressures required for the lesion treatment, pushing loads during insertion, and pulling loads during withdrawal. These loads pose a challenge especially for polymeric tubular shafts with small cross sections. In order to enable new design innovations and to better understand the mechanics of current catheter technologies, the tensile properties of polyamide (PA) 12 were investigated. PA 12 dog bone specimens and medical PA 12 tubes were either stored at ambient temperature and humidity or conditioned in water, and subjected to tensile loads at different temperatures. In addition, the effect on the tensile properties of the necking process, a forming process to reduce the wall thickness of the tubes, was determined. Results The tested tubes showed a reduction in both Young’s Modulus (− 41.5%) and yield stress (− 29.2%) compared to standardized specimens. Furthermore, an increase in temperature and water absorption softens the material and reduces the mechanical properties like the Young’s Modulus and the yield stress. It was found that the material strengthens during the necking process. Likely due to the orientation of the polymers chain molecules in load direction (Rösler et al., 2007), the Young’s Modulus of the material could be increased by 43.5%. Furthermore, the absence of a yield point after necking allows for a greater loading capacity of the material without unstable neck growth. Besides the strengthening, the ultimate strain is reduced by 50%. This indicates that the necking process induces plastic deformation. Conclusion The investigation showed that the environmental conditions like temperature and humidity can influence mechanical properties. It could also be shown that pre-forming processes such as necking can enhance the mechanical properties, such as the Young’s Modulus, while reducing the wall thickness. These findings suggest possible further development of catheters with a small cross section and higher mechanical strength and highlight the importance to account for the targeted operating temperature during the design process.

Drug-eluting balloon catheters in the treatment of left main coronary artery bifurcation lesions: 4-years follow-up

Aim To evaluate the long-term results of the use of drug-eluting balloon catheters in patients with Left Main (LM) bifurcation stenosis. Methods The analysis involved 142 patients with true bifurcations of the Left Main. Randomization in 2 main groups: Group I (n=52) included patients, who received kissing- dilatation with traditional NC balloon catheters and Group II (n=52), who had a kissing-dilatation of the main bifurcation artery with a traditional NC balloon catheters, and a side branch - with drug-eluting balloon catheters. In retrospectively, the third (III) control group (n=38) was formed, where the two-stent technique was performed. All patients from main groups had previously performed “Provisional T” stenting and final “kissing balloons” dilation technique. Coronary angiography and OCT were performed to evaluate the results of all patients. Inclusion criteria: true LM bifurcation stenoses according to QCA and OCT; SYNTAX score &lt;32. Primary endpoints: incidence of MACE - death, MI, re-interventions. Secondary endpoints: the incidence of restenosis and late stent thrombosis. Results The long-term results after 4-years were observe in 46 patients from Group I and 48 patients from Group II. Restenosis of the side branch of more than 50% according to QCA was detected in 12 patients (26.0%) from Group I and in 5 patients (10.4%) from Group II (p&lt;0.05). In-stent restenosis of the main vessel of more than 50% according to QCA was detected in 4 patients (8.6%) from Group I and in 1 patients (2.1%) from Group II (p&lt;0.05). In patients from group I, the average MLA in the side branch after 4-years compared with data after PCI was 5.58±1.34 and 4.12±1.21 mm2, respectively (p&lt;0.05), in the main branch – 6.34±1.56 and 5.88±1.14 mm2, respectively (p&gt;0.05). In patients from Group II, the average MLA were, respectively, 5.38±1.24 and 5.01±1.14 mm2 in side branch (p&gt;0.05) and 6.68±1.75 and 6.36±1.22 mm2 in main branch (p&gt;0.05). When comparing the data of MLA in the side branch in groups I and II, there was a significant difference (4.12±1.21 vs. 5.01±1.14 mm2; p&lt;0.05).The repeat revascularization, in connection with the detected ischemia was performed in 7 patients (15.2%) from Group I and in 1 patients (2.1%) from Group II (p&lt;0.05). In the Group I was observed non-fatal myocardial infarction in 2 patients (4.3%). The total incidence of MACE were 19.5 vs. 2.1% in groups I and II respectively (χ2=7.321; p&lt;0.001). The survival without MACE was 97.9 and 80.5%, respectively (p=0.0219). Conclusions The use of dug-eluting balloon catheters for the “Provisional T” stenting in patients with true LM bifurcation stenosis, associated with good prognosis and demonstrated significantly lower frequency of MACE and side branch restenosis, according to OCT data, compared with patients who used traditional NC balloon catheters for “kissing-dilatation” and two-stent technique strategy. FUNDunding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Russian academic excellence project 5-100