Project description:Transcatheter closure of patent ductus arteriosus is the standard of care. Retrieval of a duct occluder device is generally easy until it is detached from the delivery cable. We report two instances of failed retrieval of the device due to sheath tip invagination. The report highlights the importance of prompt identification of the mechanism of unforeseen complications in managing them effectively.
Project description:Lesions and neurologic disability in inflammatory CNS diseases such as multiple sclerosis (MS) result from the translocation of leukocytes and humoral factors from the vasculature, first across the endothelial blood-brain barrier (BBB) and then across the astrocytic glia limitans (GL). Factors secreted by reactive astrocytes open the BBB by disrupting endothelial tight junctions (TJs), but the mechanisms that control access across the GL are unknown. Here, we report that in inflammatory lesions, a second barrier composed of reactive astrocyte TJs of claudin 1 (CLDN1), CLDN4, and junctional adhesion molecule A (JAM-A) subunits is induced at the GL. In a human coculture model, CLDN4-deficient astrocytes were unable to control lymphocyte segregation. In models of CNS inflammation and MS, mice with astrocyte-specific Cldn4 deletion displayed exacerbated leukocyte and humoral infiltration, neuropathology, motor disability, and mortality. These findings identify a second inducible barrier to CNS entry at the GL. This barrier may be therapeutically targetable in inflammatory CNS disease.
Project description:A stent that was being implanted in the left circumflex artery, to treat an iatrogenic dissection, became dislodged at the ostial left circumflex artery on a previously deployed stent implanted for the treatment of a distal left main bifurcation stenosis. We describe here a novel technique to retrieve the device safely. (Level of Difficulty: Advanced.).
Project description:Long-term cuffed hemodialysis catheters are being increasingly used in the management of patients with chronic kidney disease. These tunneled catheters are available in different types and characteristics. Patients undergo imaging, primarily chest radiographs to confirm the position of the catheter tip. It is essential to be aware of the normal imaging appearances of these catheters as they may simulate pathological appearance due to the shape of their tips. This knowledge will help avoid misdiagnosis and unnecessary medical interventions.
Project description:IntroductionStuck tunneled central venous catheters (CVCs) have been increasingly reported. In rare cases, the impossibility of extracting the CVC from the central vein after regular traction is the result of rigid adhesions to the surrounding fibrin sheath. Forced traction during catheter removal can cause serious complications, including cardiac tamponade, hemothorax, and hemorrhagic shock. Knowledge and experience on how to properly manage the stuck catheter are still limited.Case presentationHere, we present two cases that highlight the successful removal of the stuck tunneled CVC via thoracotomy through the close collaboration of multidisciplinary specialists in the best possible way. Both patients underwent an unsuccessful attempt at thrombolytic therapy with urokinase, catheter traction under the guidance of digital subtraction angiography and intraluminal balloon dilation. And we reviewed the literature on stuck catheters in the hope of providing knowledge and effective approaches to attempted removal of stuck catheters.ConclusionThere is no standardized procedure for dealing with stuck catheters. Intraluminal percutaneous transluminal angioplasty should be considered as the first-line treatment, while open surgery represents a second option only in the event of failure. Care must be taken that forced extubation can cause patients life-threatening.
Project description:BackgroundA subeustachian pouch (SEP) often hinders the completion of a cavotricuspid isthmus (CTI) ablation of typical atrial flutter (AFL) and sometimes causes steam-pops during a power-controlled ablation. We hypothesized that real-time bull's-eye monitoring of the catheter surface temperature might be useful to locate the SEP where the temperature can rise rapidly, and a temperature-controlled ablation might avoid steam pops. This study aimed to demonstrate this hypothesis.MethodsA temperature-controlled CTI ablation with a QDOT MICRO™ catheter (n = 10) and a conventional power-controlled CTI ablation (n = 10) were performed with an output power of 35 W. During the RF application, the bull's eye monitor for monitoring the catheter surface temperatures was assessed. A "red-bull sign" was defined as an entire red-colored bull's-eye monitor, indicating that the catheter-tip temperature of all 6 thermocouples rose rapidly over 47°C.ResultsIn a total of 115 lesions (12 ± 3 per patient), a "red-bull sign" was observed in 39 (33.9%) lesions where the RF output was reduced to 26 ± 8 W. All 39 "red-bull sign" lesions corresponded to the location of the SEP as delineated by ICE before the ablation. The red-bull sign accurately indicated the presence of a SEP with a sensitivity of 84.7% and specificity of 100%. Bidirectional block of the CTI was completed in all patients in either catheter group without any steam-pops.ConclusionReal-time surface temperature monitoring and a red-bull sign might be useful to detect the SEP. A temperature-controlled CTI ablation with the QDOT MICRO catheter might be safe for avoiding steam pops.
Project description:BackgroundThe role of catheter tip shape on the safety and efficacy of radiofrequency (RF) ablation has been overlooked, although differences have been observed in clinical and research fields.ObjectiveThe purpose of this study was to analyze the role of electrode tip shape in RF ablation using a computational model.MethodsWe simulated 108 RF ablations through a realistic 3-dimensional computational model considering 2 clinically used, open-irrigated catheters (spherical and cylindrical tip), varying contact force (CF), blood flow, and irrigation. Lesions are defined by the 50°C isotherm contour and evaluated by means of width, depth, depth at maximum width, and volume. Ablations are deemed as safe, critical (tissue temperature >90°C), and pop (tissue temperature >100°C).ResultsTissue-electrode contact is less for the spherical tip at low CF but the relationship is inverted at high CF. At low CF, the cylindrical tip generates deeper and wider lesions and a 4-fold larger volume. With increasing CF, the lesions generated by the spherical tip become comparable to those generated by the cylindrical tip. The 2 tips feature different safety profiles: CF and power are the main determinants of pops for the spherical tip; power is the main factor for the cylindrical tip; and CF has a marginal effect. The cylindrical tip is more prone to pop generation at higher powers. Saline irrigation and blood flow effect do not depend on tip shape.ConclusionTip shape determines the performance of ablation catheters and has a major impact on their safety profile. The cylindrical tip shows more predictable behavior in a wide range of CF values.
Project description:Pulmonary vein reconnection after pulmonary vein isolation (PVI) is a significant problem in the treatment of paroxysmal atrial fibrillation (AF). We report about patients who underwent contact force (CF) guided PVI using CF catheter and compared them to patients with PVI using an ablation catheter with enhanced tip irrigation.A total of 59 patients were included in the analysis. In 30 patients circumferential PVI was performed using the Thermocool Smarttouch(®) ablation catheter (ST) whereas in 29 patients circumferential PVI using the Thermocool Surround Flow SF(®) ablation catheter (SF) was performed. Patients were compared in regard to procedure time, fluoroscopy time/dose as well as RF-application duration and completeness of PVI. Adverse events (pericardial effusion, PV stenosis, stroke, death) were evaluated. The presence of sinus rhythm off antiarrhythmic medication was assessed during 6 months follow-up using multiple 7 day Holter-ECGs.In both groups, all PVs were isolated without serious adverse events. Procedure time was 2.15 ± 0.5 h (ST) vs. 2.37 ± 1.13 h (SF) (p = 0.19). Duration of RF-applications was 46.6 ± 18 min (ST) and 49.8 ± 19 min (SF) (p = 0.52). Fluoroscopy time was 25.2 ± 13 min (ST) vs. 29 ± 18 min (SF), fluoroscopy dose 2675.6 ± 1658 versus 3038.3 ± 1997 cGym(2) (p = 0.36 and 0.46 respectively). Sinus rhythm off antiarrhythmic medication validated with 7 day Holter ECGs was present in both groups in 72% of patients after 6 months of follow up.PVI using the new contact force catheter is safe and effective in patients with paroxysmal AF.