Inflation Of Balloon Catheter Research Articles

Pulmonary Artery Elastic Properties After Balloon Pulmonary Angioplasty in Patients With Inoperable Chronic Thromboembolic Pulmonary Hypertension

BackgroundA significant proportion of the right ventricular afterload is determined by the elastic properties of the pulmonary artery (PA). We aimed to assess the effect of balloon pulmonary angioplasty (BPA) on PA elastic properties in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH). MethodsWe enrolled adult patients with CTEPH treated with BPA and controls without PH. Total PA compliance (CPa) was calculated as stroke volume/PA pulse pressure. PA distensibility (DC) and compliance (CC) coefficients were assessed by intravascular ultrasound to denote local elastic properties of the treated PA segments. ResultsWe performed 103 BPA sessions in 17 patients with CTEPH (5 men [29%], aged 66 [64 to 73] years) who were followed for 6 (5 to 7) months after the last BPA. The median time between BPA sessions was 39 (28 to 52) days. The CPa, CC, and DC were lower in patients with CTEPH than in controls without PH (n = 10). Complete BPA treatment led to increase of CPa from 1.02 (0.70 to 1.39) to 2.08 (1.49 to 2.39) mL/mm Hg (P < 0.001) at the 6-month follow up, and this increase was in proportion to a decrease in pulmonary vascular resistance (PVR) (R2 = 0.74; P = 0.001). CPa increased immediately after BPA session by 0.13 (–0.05; 0.33) mL/mm Hg (P = 0.001) and remained unchanged until the next BPA session. CC and DC exhibited no immediate change after catheter balloon inflation (Δ=0 [–0.03; 0.02] mm2/mm Hg, P = 0.52, and Δ = 0 [–0.13; 0.13] %/mm Hg, P = 0.91, respectively) and remained unchanged at the 6-month follow-up. ConclusionsBPA improved total CPa in proportion to a decrease in PVR despite no improvement in local elastic properties of the treated PA segments.

Percutaneous Epidural Adhesiolysis Using Inflatable Balloon Catheter and Balloon-less Catheter in Central Lumbar Spinal Stenosis with Neurogenic Claudication: A Randomized Controlled Trial

Background: When conventional interventional procedures fail, percutaneous epidural adhesiolysis (PEA), which has moderate evidence for successful treatment of lumbar spinal stenosis (LSS), has been recommended over surgical treatments. In a previous study, we demonstrated the efficacy of a newly developed inflatable balloon catheter for overcoming the access limitations of pre-existing catheters for patients with severe stenosis or adhesions. Objectives: This study compared the treatment response of combined PEA with balloon decompression and PEA only in patients with central LSS over 6 months of follow-up. Study Design: This study used a randomized, single-blinded, active-controlled trial design. Setting: This study took place in a single-center, academic, outpatient interventional pain management clinic. Methods: This randomized controlled study included 60 patients with refractory central LSS who suffered from chronic lower back pain and/or lumbar radicular pain. Patients failed to maintain improvement for &gt; 1 month with epidural steroid injection or PEA using a balloon-less catheter. Patients were randomly assigned to one of 2 interventions: balloon-less (n = 30) and inflatable balloon catheter (n = 30). The Numeric Rating Scale (NRS-11), Oswestry Disability Index (ODI), Global Perceived Effect of Satisfaction (GPES), and Medication Quantification Scale III were each measured at 1, 3, and 6 months after PEA. Results: There was a significant difference between groups in NRS-11 reduction ≥ 50% (or 4 points), ODI reduction ≥ 30% (or 10 points), GPES ≥ 6 and ≥ 4 points at 6 months, and NRS11 reduction ≥ 50% (or 4 points) at 3 months after PEA (P &lt; .03). The proportion of successful responders was higher in the balloon group than in the balloon-less group throughout the total follow-up period. Furthermore, there was a statistically significant difference between groups at 6 months after PEA (P = .035). Limitations: The results may vary according to the definition of successful response. Follow-up loss in the present study seemed to be high. Conclusion: PEA using the inflatable balloon catheter leads to significant pain reduction and functional improvement compared to PEA using the balloon-less catheter in patients with central LSS. The study protocol was approved by our institutional review board (2012-0235), and written informed consent was obtained from all patients. The trial was registered with the Clinical Research Information Service (KCT 0002093). Key words: Balloon decompression, central, chronic pain, epidural adhesiolysis, lumbar, percutaneous, radiculopathy, spinal stenosis

Active Reperfusion Hemorrhage during Thrombectomy: Angiographic Findings and Real-Time Correlation with the CT “Spot Sign”

Introduction: Symptomatic intracranial hemorrhage represents one of the most feared complications of endovascular reperfusion. We aim to describe a series of patients that experienced immediate reperfusion injury with active intraprocedural extravasation within the territory of the deep penetrating arteries and provide real-time correlation with CT “spot sign.” Methods: This was a retrospective analysis of patients that suffered reperfusion injury with active arterial extravasation during endovascular stroke treatment in two tertiary care centers. Results: Five patients were identified. Median age was 63 (58–71) years, 66% were male. Median NIHSS was 13.5 (9.5–23.0), platelet level 212,000 (142,000–235,000), baseline systolic blood pressure 152 (133–201) mm Hg, and non-contrast CT ASPECTS 7.0 (6.5–9.0). Two patients were taking aspirin and one had received intravenous thrombolysis. There were three middle cerebral artery M1, one internal carotid artery terminus, and one vertebrobasilar junction occlusion. Three patients had anterior circulation tandem occlusions. Stroke etiology was extracranial atherosclerosis (n = 2), intracranial atherosclerosis (n = 2), and cervical dissection (n = 1). The median time from onset to puncture was 5.5 (3.9–8.6) h. Intravenous heparin was administered in all patients (median dose of 4,750 [3,250–6,000] units) and intravenous abciximab in four. All tandem cases had the cervical lesion addressed first. Four lenticulostriates and one paramedian pontine artery were involved. Intraprocedural flat-panel CT was performed in four (80%) cases and provided real-time correlation between the active contrast extravasation and the “spot sign.” The bailout included use of protamine, blood pressure control, and balloon guide catheter or intracranial compliant balloon inflation plus coiling of targeted vessel. All patients had angiographic cessation of bleeding at the end of the procedure with parenchymal hemorrhage type 1 in one case and type 2 in four. Three patients had modified Rankin score of 4 and two were dead at 90 days. Conclusions: Active reperfusion hemorrhage involving perforator arteries was observed to correlate with the CT “spot sign” and to be associated with poor outcomes.

Su1449 EUS-GUIDED GASTROJEJUNOSTOMY USING A LUMEN APPOSING METAL STENT IN PATIENTS WITH SYMPTOMATIC GASTRIC OUTLET OBSTRUCTION

EUS gastrojejunostomy (GJ) is emerging as an alternative novel technique in patients with symptomatic gastric outlet obstructions (GOO) who have advanced malignancy. Recent studies have shown that the EUS-guided approach has less adverse events and is more cost-effective compared to laparoscopic GJ. We share our experience of 5 patients who underwent EUS Guided GJ with favourable outcomes. Five patients with symptomatic gastric outlet obstruction underwent EUS-guided GJ interventions from May 2017 to November 2017. Patients were informed of the potential risks of this novel procedure and informed consent was taken. Technical success was defined as successful deployment of lumen apposing metal stents (LAMS); while clinical success was the ability to tolerate diet. Median age was 61.5 (Range 53-83) years. GOO was secondary to advanced pancreatic malignancy (4) and duodenal malignancy (1). Two patients had altered anatomy from previous post bilroth gastrectomy and Roux-en-Y hepaticojejunostomy. For all five patients with GOO, LAMS 15mm diameter with electrocautery-enhanced delivery system was used to create the GJ anastomosis. Identification of the distal jejunal limb was done with an inflated balloon catheter and this was use as a target for direct puncture with a 19G needle. All five interventions had technical success with median procedure time of 80min (38-163 range). All stents were dilated up to their corresponding diameters. Duration of stay after procedure was 3-7 days and there were no adverse events post procedure such as bleeding or perforation. There were no stent migrations and stents were left in place for the rest of their life expectancy. One patient developed intermittent vomiting four weeks after stent deployment. This was possibly secondary to proximal stomach deployment, as repeated endoscopy showed a patent stent. The rest of the patients had clinical success and could tolerate diet on discharge. Range of follow up time was 1-6 months and at time of analysis GOO did not recur in all 5 patients. Three patients died due to disease progression with no symptoms of GOO prior to terminal event. EUS guided GJ is a novel procedure with favourable outcomes in patients with symptomatic GOO. Further prospective studies with larger number of patients are required to compare this new technique against the gold standard laparoscopic approach.

Characterisation of human urethral rupture thresholds for urinary catheter inflation related injuries.

Data on urethral catheter related injuries is sparse. In this study we aimed to characterise urethral diametric strain and urinary catheter inflation pressure thresholds that precede human urethral trauma during urethral catheterisation (UC). Human urethras were obtained from patients undergoing male to female gender reassignment surgery [(n = 9; age 40 ± 13.13 (range: 18-58)) years]. 12Fr urinary catheters were secured in the bulbar urethra and the catheter's anchoring balloon was inflated with a syringe pump apparatus. Urethral diametric strain and balloon pressure were characterised with video extensometry and a pressure transducer respectively. Immunohistochemistry, Masson's trichrome and Verhoeff-Van Gieson stains evaluated urethral trauma microscopically. Morphological characterisation of the urethral lumen was performed by examining non-traumatised histological sections of urethra and recording luminal area, perimeter and major/minor axis length. Tearing (n = 3) and rupture (n = 3) of the urethra were observed following catheter balloon inflation. The threshold for human urethral rupture occurred at an external urethral diametric strain ≥ 27% and balloon inflation pressure ≥ 120kPa. Significant relationships were identified between urethral wall thickness and the level of trauma induced during catheter balloon inflation (p = 0.001) and between the pressure required to inflate the catheter balloon and the length of the major axis of the urethral lumen (p = 0.004). Ruptured urethras demonstrated complete transection of collagen, elastin and muscle fibres. In conclusion, urethral rupture occurs at an external urethral diametric strain ≥ 27% or with balloon inflation pressures ≥ 120 kPa. Incorporation of these parameters may be useful for designing a safety mechanism for preventing catheter inflation related urethral injuries.

Clinical Evaluation of a Safety-device to Prevent Urinary Catheter Inflation Related Injuries

To evaluate the feasibility of a novel "safety-valve" device for preventing catheter related urethral trauma during urethral catheterization (UC). To assess the opinions of clinicians on the performance of the safety-valve device. A validated prototype "safety-valve" device for preventing catheter balloon inflation related urethral injuries was prospectively piloted in male patients requiring UC in a tertiary referral teaching hospital (n = 100). The device allows fluid in the catheter system to decant through an activated safety threshold pressure valve if the catheter anchoring balloon is misplaced. Users evaluated the "safety-valve" with an anonymous questionnaire. The primary outcome measurement was prevention of anchoring balloon inflation in the urethra. Secondary outcome measurement was successful inflation of urinary catheter anchoring balloon in the bladder. Patient age was 76 ± 12 years and American Society of Anaesthesiologists grade was 3 ± 1.4. The "safety-valve" was utilized by 34 clinicians and activated in 7% (n = 7/100) patients during attempted UC, indicating that the catheter anchoring balloon was incorrectly positioned in the patient's urethra. In these 7 cases, the catheter was successfully manipulated into the urinary bladder and inflated. 31 of 34 (91%) clinicians completed the questionnaire. Ten percent (n = 3/31) of respondents had previously inflated a urinary catheter anchoring balloon in the urethra and 100% (n = 31) felt that a safety mechanism for preventing balloon inflation in the urethra should be compulsory for all UCs. The safety-valve device piloted in this clinical study offers an effective solution for preventing catheter balloon inflation related urethral injuries.

8-F balloon guide catheter for embolization of anterior circulation aneurysms: an institutional experience in 152 patients.

ABSTRACTThe use of 8-F balloon guide catheter (BGC) for proximal flow control was previously shown to prevent distal embolic complications during mechanical clot retrieval in patients with acute ischemic stroke. In this retrospective study, the utility of 8-F BGCs for proximal flow control during endovascular coiling of anterior circulation aneurysms was investigated. Patients who underwent endovascular coiling for anterior circulation aneurysms between August 2013 and December 2016 were retrospectively analyzed. Among a total of 152 patients included in this series, 64 patients presented with aneurysmal rupture, whereas the aneurysms were detected incidentally or due to mass effects in the remaining patients. 8-F BGCs were successfully navigated in all patients. The balloon was inflated during navigation in 19 patients. Inflation of the catheter balloon during coil embolization was required in 34 patients; this was performed as an emergency maneuver in six of these patients. Thromboembolic complications occurred in one patient. 8-F BGC can be effectively used for proximal flow control during endovascular treatment of anterior circulation aneurysms. The other advantages included improved navigation of tortuous arterial anatomy, coil stabilization during aneurysmal coiling, and freedom to utilize aneurysmal neck-remodeling balloons for additional adjunctive techniques or to deploy rescue stents. This novel approach might be safely and effectively used in patients undergoing endovascular treatment for anterior circulation aneurysms.

Evidence of bone marrow downregulation in brain-dead rats.

Experimental findings support the evidence of a persistent leucopenia triggered by brain death (BD). This study aimed to investigate leucocyte behaviour in bone marrow and blood after BD in rats. BD was induced using intracranial balloon catheter inflation. Sham-operated (SH) rats were trepanned only. Thereafter bone marrow cells were harvested every six hours from the femoral cavity and used for total and differential counts. They were analysed further by flow cytometry to characterize lymphocyte subsets, granulocyte adhesion molecules expression and apoptosis/necrosis [annexin V/propidium iodide (PI) protocol]. BD rats exhibited a reduction in bone marrow cells due to a reduction in lymphocytes (40%) and segmented cells (45%). Bone marrow lymphocyte subsets were similar in BD and SH rats (CD3, P=0.1; CD4, P=0.4; CD3/CD4, P=0.4; CD5, P=0.4, CD3/CD5, P=0.2; CD8, P=0.8). Expression of L-selectin and beta2 -integrins on granulocytes did not differ (CD11a, P=0.9; CD11b/c, P=0.7; CD62L, P=0.1). There were no differences in the percentage of apoptosis and necrosis (Annexin V, P=0.73; PI, P=0.21; Annexin V/PI, P=0.29). In conclusion, data presented suggest that the downregulation of the bone marrow is triggered by brain death itself, and it is not related to changes in lymphocyte subsets, granulocyte adhesion molecules expression or apoptosis and necrosis.

Integration of optical applicator with balloon catheter for photothermal treatment of biliary stricture.

Bile duct stricture is an uncommon disease in gastroenterology resulting from postoperative trauma. In spite of non-surgical treatments, clinical outcomes for the biliary strictures still encounter high restenosis and stent migration. The objective of the current study was to investigate the feasible application of a balloon catheter-integrated diffing applicator to thermally treat the bile duct stricture. 400-μm optical fibers were micro-machined and then integrated with an inflatable balloon catheter. The fabricated applicator was tested on porcine bile ducts with 20-W 980 nm laser light for 60 s, and a thermal camera was used to measure thermal response of the tissue. Due to mechanical pressure, the inflated balloon was able to expand the tissue lumen up to 6 mm in diameter. Compared to control, the inner area of the treated tissue was increased by four fold (i.e., 2.74±0.05 mm2 for treated vs. 0.73±0.14 mm2 for control) during the balloon catheter-assisted laser irradiation. The laser-induced tissue temperature reached up to 80.1±6.4 °C (thermal gradient = 1.2 °C/s). A thin layer of coagulation necrosis (0.5±0.1 mm) consistently formed around the lumen. The proposed balloon catheter-integrated diffusing applicator can be a feasible minimally invasive device to photothermally treat the obstructive bile ducts. Lasers Surg. Med. 49:781-786, 2017. © 2017 Wiley Periodicals, Inc.

685 - Preventing urethral trauma from inadvertent inflation of catheter balloon in the urethra during catheterization: Evaluation of a novel safety syringe after correlating trauma with urethral distension and catheter balloon pressure

685 - Preventing urethral trauma from inadvertent inflation of catheter balloon in the urethra during catheterization: Evaluation of a novel safety syringe after correlating trauma with urethral distension and catheter balloon pressure

Effective Management of Bone Fractures with the Illuminoss® Photodynamic Bone Stabilization System: Initial Clinical Experience from the European Union Registry.

The IlluminOss® system (IS) uses a light-curable polymer contained within an inflatable balloon catheter, forming a patient customized intramedullary implant. A registry was established in Germany and The Netherlands to prospectively collect technical and clinical outcomes in patients treated with IS for fractures of the phalange, metacarpal, radius, ulna, distal radius, fibula, clavicle and/or olecranon. Humeral, femoral, tibial and pelvic fractures were included under compassionate use. Procedural success included successful placement of the device at the target fracture site and achievement of fracture stabilization. Clinical and radiographic assessments were made postoperatively through 12 months. One hundred thirty two patients (149 fractures) were enrolled with most fractures (85%) resulting from low-energy trauma. Simple fractures predominated (47%) followed by complex (23%) and wedge (16%) fractures. Procedural success was achieved in all patients and no implants required removal or revision. Normal range of motion was realized in 87% of fractures. Radiographically, there was substantial cortical bridging, total dissolution of the fracture line, and complete fracture healing. Across a variety of fracture types, the IS provides a safe and effective approach for rapid healing and functional recovery.

Quantification of User and Manufacturer Variabilities in Urinary Catheter Anchoring Balloon Inflation and Mitigation of Variability by Flow Resistance

To quantify user variability and manufacturer variability in urinary catheter anchoring balloon inflation pressure and to mitigate any significant variance by incorporating flow resistance into the anchoring balloon inflation process. Inflation of a urinary catheter anchoring balloon was performed at atmospheric pressure by different users (n = 8) to investigate user variability. A calibrated pressure transducer measured inflation pressures, and a video extensometer measured balloon inflation profiles. Manufacturer variability was investigated by applying constant forces to the plunger of conventional syringes to mimic "heavy-," "intermediate-," and "light"-handed users for 3 brands of catheter. Flow restrictors of variable reduced cross-sectional areas were introduced to the outflow of the inflation syringes to investigate the effect of flow resistance on anchoring balloon inflation profiles. Variations in maximum inflation pressures (range: 75-355 kPa) were observed among the different users. There were no significant differences in maximum inflation pressure between brands at any of the 3 simulated hand forces (P = .97). Increasing the flow resistance significantly reduces the applicable inflation pressure of all hand forces (P < .001). Specifically, the difference in inflation pressure between heavy- and light-handed forces is reduced from over 405 kPa to under 65 kPa. Introducing flow resistance does not result in a significant difference in inflation pressure between brands (P = .254). There is significant user variability in urinary catheter balloon inflation pressure. This variation can be significantly reduced by introducing flow resistance to the inflation technique.

Technique of spinal cord compression induced by inflation of epidural balloon catheter in rabbits (Oryctologus cuniculus): efficient and easy to use model.

The most common cause of spinal cord injury are high impact trauma, which often result in some motor impairment, sensory or autonomic a greater or lesser extent in the distal areas the level of trauma. In terms of survival and complications due to sequelae, veterinary patients have a poor prognosis unfavorable. Therefore justified the study of experimental models of spinal cord injury production that could provide more support to research potential treatments for spinal cord injuries in medicine and veterinary medicine. Preclinical studies of acute spinal cord injury require an experimental animal model easily reproducible. The most common experimental animal model is the rat, and several techniques for producing a spinal cord injury. The objective of this study was to describe and evaluate the effectiveness of acute spinal cord injury production technique through inflation of Fogarty(r) catheter using rabbits as an experimental model because it is a species that has fewer conclusive publications and contemplating. The main requirements of a model as low cost, handling convenience, reproducibility and uniformity. The technique was adequate for performing preclinical studies in neuro-traumatology area, effectively leading to degeneration and necrosis of the nervous tissue fostering the emergence of acute paraplegia.

The risk of intra-urethral Foley catheter balloon inflation in spinal cord-injured patients: Lessons learned from a retrospective case series.

BackgroundInflating the balloon of Foley catheter in urethra is a complication of urethral catheterisation. We report five patients in whom this complication occurred because of unskilled catheterisation. Due to lack of awareness, the problem was not recognised promptly and patients came to harm.Case seriesA tetraplegic patient developed pain in lower abdomen and became unwell after transurethral catheterisation. CT pelvis revealed full bladder with balloon of Foley catheter in dilated urethra.Routine ultrasound examination in an asymptomatic tetraplegic patient with urethral catheter drainage, revealed Foley balloon in the urethra. He was advised to get catheterisations done by senior health professionals.A paraplegic patient developed bleeding and bypassing after transurethral catheterisation. X-ray revealed Foley balloon in urethra; urethral catheter was changed ensuring its correct placement in urinary bladder. Subsequently, balloon of Foley catheter was inflated in urethra several times by community nurses, which resulted in erosion of bulbous urethra and urinary fistula. Suprapubic cystostomy was performed.A tetraplegic patient developed sweating and increased spasms following urethral catheterisations. CT of abdomen revealed distended bladder with the balloon of Foley catheter located in urethra. Flexible cystoscopy and transurethral catheterisation over a guide-wire were performed. Patient noticed decrease in sweating and spasms.A paraplegic patient developed lower abdominal pain and nausea following catheterisation. CT abdomen revealed bilateral hydronephrosis and hydroureter and Foley balloon located in urethra. Urehral catheterisation was performed over a guide-wire after cystoscopy. Subsequently suprapubic cystostomy was done.ConclusionSpinal cord injury patients are at increased risk for intra-urethral Foley catheter balloon inflation because of lack of sensation in urethra, urethral sphincter spasm, and false passage due to previous urethral trauma. Education and training of doctors and nurses in proper technique of catheterisation in spinal cord injury patients is vital to prevent intra-urethral inflation of Foley catheter balloon. If a spinal cord injury patient develops bypassing or symptoms of autonomic dysreflexia following catheterisation, incorrect placement of urethral catheter should be suspected.

Endoscopic endonasal control of the paraclival internal carotid artery by Fogarty balloon catheter inflation: an anatomical study.

OBJECTIVE Neurosurgical management of many vascular and neoplastic lesions necessitates control of the internal carotid artery (ICA). The aim of this study was to investigate the feasibility of achieving control of the ICA through the endoscopic endonasal approach by temporary occlusion with a Fogarty balloon catheter. METHODS Ten endoscopic endonasal paraseptal approaches were performed on cadaveric specimens. A Fogarty balloon catheter was inserted through a sellar bony opening and pushed laterally and posteriorly extraarterially along the paraclival carotid artery. The balloon was then inflated, thus achieving temporary occlusion of the vessel. The position of the catheter was confirmed with CT scans, and occlusion of the ICA was demonstrated with angiography. The technique was performed in 2 surgical cases of pituitary macroadenoma with cavernous sinus invasion. RESULTS Positioning the Fogarty balloon catheter at the level of the paraclival ICA was achieved in all cadaveric dissections and surgical cases through a minimally invasive, quick, and safe approach. Inflation of the Fogarty balloon caused interruption of blood flow in 100% of cases. CONCLUSIONS Temporary occlusion of the paraclival ICA performed through the endoscopic endonasal route with the aid of a Fogarty balloon catheter may be another maneuver for dealing with intraoperative ICA control. Further clinical studies are required to prove the efficacy of this method.

Duplex derived intrarenal resistance index correlates with invasive pressure gradient measurements in detecting relevant unilateral renal artery stenosis.

The purpose of this study was to assess the correlation between the transstenotic pressure gradient as determined by a pressure wire and the decrease in the intrarenal resistance index (RI) > 0.05 measured by duplex ultrasound in significant unilateral renal artery stenosis (RAS). Intravascular ultrasound (IVUS) was correlated to the angiographic degree of RAS. In 17 patients, transstenotic pressure gradient measurements, IVUS and RI measurements were obtained before and after stenting. After stenting, graded stenosis was created by progressive balloon catheter inflation. Stenosis severity was expressed as the ratio of the distal pressure (Pd) corrected for aortic pressure (Pa). The balloon inflation pressure was adjusted to create a stenosis with Pd/Pa ratio 1.0 to 0.7. In parallel, RI measurements were performed in the affected kidney and compared to the contralateral kidney for the calculation of the side-difference in RI. IVUS was performed to correlate the cross-sectional degree of stenosis with quantitative angiography (QA). In 60 out 68 measurements, the RI difference (decline > 0.05) correlated with a Pd/Pa ratio < 0.9; this correlation was significant by linear regression analysis (p < 0.001). The preinterventional mean degree of stenosis was 63.4 % + 16.1 (24.6 - 84.6 %) as assessed by QA and 76.7 % + 13.2 % (47 - 92 %) as assessed by IVUS, showing a significant correlation (p < 0.035). In unilateral RAS, a drop in RI > 0.05 as compared to the unaffected kidney correlates to an invasively measured Pd/Pa ratio < 0.9, which is regarded as a significant pressure gradient associated with increased renin production, which promotes renovascular hypertension. QA underestimates RAS severity as compared to IVUS.

Two-Point Stretchable Electrode Array for Endoluminal Electrochemical Impedance Spectroscopy Measurements of Lipid-Laden Atherosclerotic Plaques.

Four-point electrode systems are commonly used for electric impedance measurements of biomaterials and tissues. We introduce a 2-point system to reduce electrode polarization for heterogeneous measurements of vascular wall. Presence of endoluminal oxidized low density lipoprotein (oxLDL) and lipids alters the electrochemical impedance that can be measured by electrochemical impedance spectroscopy (EIS). We developed a catheter-based 2-point micro-electrode configuration for intravascular deployment in New Zealand White rabbits. An array of 2 flexible round electrodes, 240µm in diameter and separated by 400µm was microfabricated and mounted on an inflatable balloon catheter for EIS measurement of the oxLDL-rich lesions developed as a result of high-fat diet-induced hyperlipidemia. Upon balloon inflation, the 2-point electrode array conformed to the arterial wall to allow deep intraplaque penetration via alternating current (AC). The frequency sweep from 10 to 300kHz generated an increase in capacitance, providing distinct changes in both impedance (Ω) and phase (ϕ) in relation to varying degrees of intraplaque lipid burden in the aorta. Aortic endoluminal EIS measurements were compared with epicardial fat tissue and validated by intravascular ultrasound and immunohistochemistry for plaque lipids and foam cells. Thus, we demonstrate a new approach to quantify endoluminal EIS via a 2-point stretchable electrode strategy.

Aortic Dissection Caused by Percutaneous Coronary Intervention: 2 New Case Reports and Detailed Analysis of 86 Previous Cases

Aortic dissection, a rare sequela of percutaneous coronary intervention, can be fatal when it is not recognized and treated promptly. Treatment varies from conservative management to invasive aortic repair and revascularization. We report the cases of 2 patients whose aortic dissection was caused by percutaneous coronary intervention. In addition, we present detailed analyses of 86 previously reported cases. Aortic dissection was most often seen during intervention to the right coronary artery (in 76.7% of instances). The 2 most frequently reported causes were catheter trauma (in 54% of cases) and balloon inflation (in 23.8%). The overall mortality rate was 7.1%. We conclude that most patients can be treated conservatively or by means of stenting alone, with no need for surgical intervention.

Right heart catheterisation: best practice and pitfalls in pulmonary hypertension.

Right heart catheterisation (RHC) plays a central role in identifying pulmonary hypertension (PH) disorders, and is required to definitively diagnose pulmonary arterial hypertension (PAH). Despite widespread acceptance, there is a lack of guidance regarding the best practice for performing RHC in clinical practice. In order to ensure the correct evaluation of haemodynamic parameters directly measured or calculated from RHC, attention should be drawn to standardising procedures such as the position of the pressure transducer and catheter balloon inflation volume. Measurement of pulmonary arterial wedge pressure, in particular, is vulnerable to over- or under-wedging, which can give rise to false readings. In turn, errors in RHC measurement and data interpretation can complicate the differentiation of PAH from other PH disorders and lead to misdiagnosis. In addition to diagnosis, the role of RHC in conjunction with noninvasive tests is widening rapidly to encompass monitoring of treatment response and establishing prognosis of patients diagnosed with PAH. However, further standardisation of RHC is warranted to ensure optimal use in routine clinical practice.

Foley balloon catheter to prevent or manage bleeding during treatment for cervical and Cesarean scar pregnancy.

To demonstrate the efficacy of placement and inflation of Foley balloon catheters prophylactically to prevent, or as an adjuvant therapy to control, bleeding in women undergoing treatment for Cesarean scar pregnancy (CSP) or cervical pregnancy (CxP). This was a retrospective study of 18 women with either CSP (n = 16) or CxP (n = 2), who underwent Foley balloon catheter placement under continuous transvaginal or transabdominal ultrasound guidance to prevent or manage bleeding following treatment, which in most cases comprised local (intragestational sac) and intramuscular (IM) methotrexate (MTX) injections. In eight cases, the balloon catheter was placed immediately following local and/or IM MTX treatment, either because of bleeding or prophylactically; in eight cases, the catheter was placed as part of a two-step protocol, with patients first treated with local and IM MTX injection, then suction aspiration on Day 4 or 5, followed by planned insertion of a balloon catheter; in one patient the balloon was placed on Day 21 after local and IM MTX treatment, due to sudden bleeding; and in one case of a heterotopic pregnancy, one intrauterine and one cervical, the balloon was placed due to severe bleeding. Human chorionic gonadotropin (hCG) levels were evaluated weekly following MTX injection. Gestational ages at balloon placement ranged between 5 and 12 + 2 weeks. All embryos/fetuses, with the exception of the cervical heterotopic one, had heart activity and catheter placement was well-tolerated by all women. The balloon tamponade effectively reduced or prevented maternal vaginal bleeding in all except one patient; this woman had a heterotopic CxP and required abdominal robotic cerclage to control the bleeding. Catheters were kept in place for a mean of 3.6 (range, 1-6) days. hCG levels returned to low or zero levels within 19-82 days following MTX injection. Fifteen women required antibiotic treatment following the procedure. One woman with CSP developed an arteriovenous malformation requiring uterine artery embolization. Ultrasound-guided placement and inflation of Foley balloon catheters was easy to perform and well-tolerated by patients undergoing treatment for CSP or CxP, and successfully prevented or helped in the management of bleeding complications. Based on our experience and previous publications we suggest having the option of balloon catheter insertion available when local treatment of CSP or CxP is undertaken.