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Balloon Occlusion (balloon + occlusion)
Selected AbstractsA Model of Ischemically Induced Ventricular Fibrillation for Comparison of Fixed-dose and Escalating-dose Defibrillation StrategiesACADEMIC EMERGENCY MEDICINE, Issue 6 2004James T. Niemann MD Abstract Objectives: Fixed- and escalating-dose defibrillation protocols are both in clinical use. Clinical observations suggest that the probability of successful defibrillation is not constant across a population of patients with ventricular fibrillation (VF). Common animal models of electrically induced VF do not represent a clinical VF etiology or reproduce clinical heterogeneity in defibrillation probability. The authors hypothesized that a model of ischemically induced VF would exhibit heterogeneous defibrillation shock strength requirements and that an escalating-dose strategy would more effectively achieve prompt defibrillation. Methods:Forty-six swine were randomized to fixed, lower-energy (150 J) transthoracic shocks (group 1) or escalating, higher-energy (200 J,300 J,360 J) shocks (group 2). VF was induced by balloon occlusion of a coronary artery. After 1 or 5 minutes of VF, countershocks with a biphasic waveform were administered. The primary endpoint was successful defibrillation (termination of VF for 5 seconds) with ,3 shocks. Results: VF was induced with occlusion or after reperfusion in 35 animals. Only five of 17 group 1 animals (29%, 95% CI = 10 to 56) could be defibrillated with ,3 shocks; 15 of 18 group 2 animals (83%, 95% CI = 59 to 96) were defibrillated with ,3 shocks (p < 0.002 vs. group 1). Nine of the group 1 animals (75%) that could not be defibrillated with 150-J shocks were rescued with ,3 shocks ranging from 200 to 360 J. Conclusions: In this ischemic VF animal model, defibrillation shock strength requirements varied among individuals, and when defibrillation was difficult, an escalating-dose strategy was more effective for prompt defibrillation than fixed, lower-energy shocks. [source] The Permanency of Pulmonary Vein Isolation Using a Balloon Cryoablation CatheterJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2010HUMERA AHMED B.A. Chronic PV Isolation With the Cryoballoon.,Background: Because of its technical feasibility and presumed safety benefits, balloon cryoablation is being increasingly employed for pulmonary vein (PV) isolation. While acute isolation has been demonstrated in most patients, little data are available on the chronic durability of cryoballoon lesions. Methods and Results: Twelve atrial fibrillation patients underwent PV isolation using either a 23-mm or 28-mm cryoballoon. For each vein, after electrical isolation was verified with the use of a circular mapping cathether, 2 bonus balloon ablation lesions were placed. Gaps in balloon occlusion were overcome using either a spot cryocatheter or a "pull-down" technique. A prespecified second procedure was performed at 8,12 weeks to assess for long-term PV isolation. Acute PV isolation was achieved in all PVs in the patient cohort (n = 48 PVs), using the cryoballoon alone in 47/48 PVs (98%); a "pull-down" technique was employed for 5 PVs (1 right superior pulmonary vein, 2 right inferior pulmonary veins, and 2 left inferior pulmonary veins). The gap in the remaining vein was ablated with a spot cryocatheter. During the second mapping procedure, 42 of 48 PVs (88%) remained isolated. One vein had reconnected in 2 patients, while 2 veins had reconnected in another 2 patients. All PVs initially isolated with the "pull-down" technique remained isolated at the second procedure. Conclusions: Cryoballoon ablation allows for durable PV isolation with the use of a single balloon. With maintained chronic isolation in most PVs, it may represent a significant step toward consistent and lasting ablation procedures. (J Cardiovasc Electrophysiol, Vol. pp. 731-737, July 2010) [source] Hypertrophied hearts: what of sevoflurane cardioprotection?ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2009J. R. LARSEN Background: Recent studies have demonstrated that inhalation anaesthetics, like sevoflurane, confer cardioprotection both experimentally and clinically. However, coexisting cardiac disease might diminish anaesthetic cardioprotection and could partly explain why the clinical results of cardioprotection with anaesthetics remain controversial , in contrast to solid experimental evidence. Concomitant left ventricular hypertrophy is found in some cardiac surgery patients and could change cardioprotection efficacy. Hypertrophy could potentially render the heart less susceptible to sevoflurane cardioprotection and more susceptible to ischaemic injury. We investigated whether hypertrophy blocks sevoflurane cardioprotection, and whether tolerance to ischaemia is altered by left ventricular hypertrophy, in an established experimental animal model of ischaemia,reperfusion. Methods: Anaesthetized juvenile pigs (n=7,12/group) were subjected to 45 min distal coronary artery balloon occlusion, followed by 120 min of reperfusion. Controls were given pentobarbital, while sevoflurane cardioprotection was achieved by 3.2% inhalation throughout the experiment. Chronic banding of the ascending aorta resulted in left ventricular hypertrophy development in two further groups and these animals underwent identical ischaemia,reperfusion protocols, with or without sevoflurane cardioprotection. Myocardial infarct sizes were compared post-mortem. Results: The mean myocardial infarct size (% of area-at-risk) was reduced from mean 55.0 (13.6%) (±SD) in controls to 17.5 (13.2%) by sevoflurane (P=0.001). Sevoflurane reduced the infarct size in hypertrophied hearts to 14.6 (10.4%) (P=0.001); however, in hypertrophic controls, infarcts were reduced to 34.2 (10.2%) (P=0.001). Conclusion: Sevoflurane abrogated ischaemic injury to similar levels in both normal and left ventricular hypertrophied hearts. [source] Transvenous Intramyocardial Cellular Delivery Increases Retention in Comparison to Intracoronary Delivery in a Porcine Model of Acute Myocardial InfarctionJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 5 2008JON C. GEORGE M.D. Background: Clinical trials using intracoronary (IC) delivery of cells have addressed efficacy but the optimal delivery technique is unknown. Our study aimed to determine whether transvenous intramyocardial (TVIM) approach was advantageous for cellular retention in AMI. Methods: Domestic pigs (n = 4) underwent catheterization with coronary angiography and ventriculography prior to infarction and pre- and post-cells. Pigs underwent 90-minute balloon occlusion of the left anterior descending artery (LAD). After one week they were prepared for IC (n = 2) or TVIM (n = 2) delivery of bone marrow mononuclear cells (MNC) labeled with GFP. IC infusion used an over-the-wire catheter to engage the LAD and balloon inflation to prevent retrograde flow. Venography via the coronary sinus was used for TVIM delivery. The anterior interventricular vein was engaged with a guidewire allowing use of the TransAccessÔ catheter that is outfitted with an ultrasound tip for visualization. Animals were sacrificed one hour after delivery and tissue was analyzed. Results: Procedures were performed without complication and monitoring was uneventful. 1 × 108 MNC were isolated from each bone marrow (BM) preparation and 1 × 107 MNC delivered. Ventriculography at one week revealed wall motion abnormalities consistent with an anterior AMI. TVIM and IC delivery revealed mean 452 cells per section and 235 cells per section on average, respectively, in the infarct zone (P = 0.01). Conclusion: We have demonstrated that TVIM approach for cell delivery is feasible and safe. Moreover, this approach may provide an advantage over IC infusion in retention of the cellular product; however, larger studies will be necessary. [source] Flow-Reversal Device for Cerebral Protection During Carotid Artery Stenting,Acute and Long-Term ResultsJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 1 2006KASJA RABE M.D. Objective: Several types of cerebral (embolic) protection devices have been used in patients undergoing carotid stenting. This study assessed results achieved with a flow-reversal system. Method: Carotid stenting was performed in 56 patients (mean age, 68 ± 9 years). The mean percentage of stenosis was 77%± 10%. During the procedure, cerebral protection was achieved by means of balloon occlusion of the common and external carotid artery with use of a Parodi Anti-Emboli System. The patients' neurologic status was assessed during the intervention; at discharge; 1, 6, and 12 months after the procedure; and yearly thereafter. Results: The procedure was technically successful in all cases. One patient had a minor stroke 6 hours after the intervention. No major strokes, deaths, or myocardial infarctions occurred. During long-term follow-up (to 40 months), 2 patients died of a secondary complication after intracerebral bleeding and stroke and 1 died as a result of ventricular fibrillation. Restenosis did not exceed 50% of vessel diameter in any patient. Conclusions: The acute results indicate that proximal occlusion and flow reversal for cerebral protection during carotid stenting is a safe and effective method. The low restenosis and complication rate during long-term follow-up is in accordance with other series of carotid angioplasty and shows that the occlusion balloons do not cause any long-term side effects. [source] Dynamic observation of pulmonary perfusion using continuous arterial spin-labeling in a pig modelJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2001David A. Roberts MD Abstract The continuous arterial spin-labeling (CASL) method of perfusion MRI is used to observe pulmonary perfusion dynamically in an animal model. Specifically, a respiratory-triggered implementation of the CASL method is used with approximate spatial resolution of 0.9 × 1.8 × 5.0 mm (0.008 cc) and 2-minute temporal resolution. Perfusion MRI is performed dynamically during repeated balloon occlusion of a segmental pulmonary artery, as well as during pharmacological stimulation. A total of three Yorkshire pigs were studied. The results demonstrate the ability of the endogenous spin-labeling method to characterize the dynamic changes in pulmonary perfusion that occur during important physiological alterations. J. Magn. Reson. Imaging 2001;14:175,180. © 2001 Wiley-Liss, Inc. [source] Neurological outcome after experimental cardiopulmonary resuscitation: a result of delayed and potentially treatable neuronal injury?ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 5 2002X. L. Liu Background: In experimental cardiopulmonary resuscitation (CPR) aortic balloon occlusion, vasopressin, and hypertonic saline dextran administration improve cerebral blood flow. Free radical scavenger ,-phenyl-N-tert-butyl-nitrone (PBN) and cyclosporine-A (CsA) alleviate neuronal damage after global ischemia. Combining these treatments, we investigated neurological outcome after experimental cardiac arrest. Methods: Thirty anesthetized piglets, randomly allocated into three groups, were subjected to 8 min of ventricular fibrillation followed by 5 min of closed-chest CPR. The combined treatment (CT) group received all the above-mentioned modalities; group B was treated with balloon occlusion and epinephrine; and group C had sham balloon occlusion with epinephrine. Indicators of oxidative stress (8-iso-PGF2,), inflammation (15-keto-dihydro-PGF2,), energy crisis (hypoxanthine and xanthine), and anoxia/hypoxia (lactate) were monitored in jugular bulb venous blood. Neurological outcome was evaluated 24 h after CPR. Results: Restoration of spontaneous circulation (ROSC) was more rapidly achieved and neurological outcome was significantly better in the CT group, although there was no difference in coronary perfusion pressure between groups. The jugular venous PCO2 and cerebral oxygen extraction ratio were lower in the CT group at 5,15 min after ROSC. Jugular venous 8-iso-PGF2, and hypoxanthine after ROSC were correlated to 24 h neurological outcome Conclusions: A combination of cerebral blood flow promoting measures and administration of ,-phenyl-N-tert-butyl-nitrone and cyclosporine-A improved 24 h neurological outcome after 8 min of experimental normothermic cardiac arrest, indicating an ongoing neuronal injury in the reperfusion phase. [source] Blood transfusion for caesarean delivery complicated by placenta praeviaAUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 6 2009R. K. BOYLE Aim:, This study was undertaken to determine if the need for red cell blood transfusion in placenta praevia could be predicted. Methods:, Data from a retrospective observational study of 246 obstetric patients, with placenta praevia, from 1999 to 2005 were analysed to generate a model to predict requirement for transfusion. Results:, Seventy-one patients were transfused. Independent risk factors for transfusion were gestational age at delivery of 32,35 weeks [odds ratio (OR): 2.6; 95% confidence interval (CI): 1.1,6.4] and caesarean combined with hysterectomy (OR: 29.4; 95% CI: 5.9,145.9; P < 0.001). No independent risk of transfusion was associated with maternal age, race, parity, smoking status, type of anaesthesia, caesarean combined with arterial balloon occlusion, grade of placenta, accreta and previous uterine surgery. Conclusions:, Gestational age at delivery and type of surgery required are predictors of transfusion during caesarean for placenta praevia. Arterial balloon occlusion does not appear to increase transfusion risk and may be considered as one of the techniques in management. [source] Thromboembolism of the leg following prophylactic balloon occlusion of the uterine arteriesBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 9 2009S Chouliaras No abstract is available for this article. [source] Safety and effectiveness of the INVATEC MO.MA® proximal cerebral protection device during carotid artery stenting: Results from the ARMOUR pivotal trial,CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 1 2010Gary M. Ansel MD Abstract Objective: The multicenter ARMOUR (ProximAl PRotection with the MO.MA Device DUring CaRotid Stenting) trial evaluated the 30-day safety and effectiveness of the MO.MA® Proximal Cerebral Protection Device (Invatec, Roncadelle, Italy) utilized to treat high surgical risk patients undergoing carotid artery stenting (CAS). Background: Distal embolic protection devices (EPD) have been traditionally utilized during CAS. The MO.MA device acts as a balloon occlusion "endovascular clamping" system to achieve cerebral protection prior to crossing the carotid stenosis. Methods: This prospective registry enrolled 262 subjects, 37 roll-in and 225 pivotal subjects evaluated with intention to treat (ITT) from September 2007 to February 2009. Subjects underwent CAS using the MO.MA device. The primary endpoint, myocardial infarction, stroke, or death through 30 days (30-day major adverse cardiac and cerebrovascular events [MACCE]) was compared to a performance goal of 13% derived from trials utilizing distal EPD. Results: For the ITT population, the mean age was 74.7 years with 66.7% of the cohort being male. Symptomatic patients comprised 15.1% and 28.9% were octogenarians. Device success was 98.2% and procedural success was 93.2%. The 30-day MACCE rate was 2.7% [95% CI (1.0,5.8%)] with a 30-day major stroke rate of 0.9%. No symptomatic patient suffered a stroke during this trial. Conclusions: The ARMOUR trial demonstrated that the MO.MA® Proximal Cerebral Protection Device is safe and effective for high surgical risk patients undergoing CAS. The absence of stroke in symptomatic patients is the lowest rate reported in any independently adjudicated prospective multicenter registry trial to date. © 2010 Wiley-Liss, Inc. [source] The effect of transient balloon occlusion of the mitral valve on left atrial appendage blood flow velocity and spontaneous echo contrastCLINICAL CARDIOLOGY, Issue 7 2000Jianan Wang M.D. Abstract Background: Spontaneous echo contrast (SEC) is a phenomenon that is commonly seen in areas of blood stasis. It is a slowly moving, cloud-like swirling pattern of "smoke" or increased echogenicity recorded on echocardiography. SEC is commonly seen in the left atrium of patients with mitral stenosis or atrial fibrillation. The prescence of SEC has been shown to be a marker of increased thromboembolic risk. Hypothesis: By using transesophageal echocardiography during percutaneous balloon mitral valvotomy (PBMV), the study investigated the relationship between SEC and varying left atrial appendage (LAA) blood flow velocity in the human heart. Methods: Thirty,five patients with rheumatic mitral stenosis underwent percutaneous balloon mitral valvotomy with intraoperative transesophageal echocardiography monitoring. We alternatively measured LAA velocities and observed the left atrium for various grades of SEC (0 = none to 4 = severe) before and after each balloon inflation. Results: Left atrial appendage maximal ejection velocity was reduced from 35 ± 14 to 6 ± 2 mm/s at peak balloon inflation and increased to 40 ± 16 mm/s after balloon deflation. In comparison with the values before balloon inflation and after balloon deflation, LAA velocities were significantly lower (p < 0.001). New or increased SEC grade was observed during 54 of 61 (88%) inflations and unchanged in 7 (12%) inflations at peak balloon inflation. Spontaneous echo contrast became lower in grade after 55 balloon deflations (90%), completely disappeared after 18 deflations (30%), and remained unchanged after 6 deflations (10%). The mean time to achieve maximal SEC grade (2.5 ± 1.2 s) coincided with the mean time to trough LAA velocities (2.3 ±1.1 s) after balloon inflation. Upon deflation, the mean time to lowest SEC grade (2.9 ± 1.8 s) coincided with mean time to achieve maximal LAA velocities (2.7 ± 1.6s). Conclusion: During balloon inflation, the severity of SEC was enhanced with corresponding reduction in LAA flow velocity. Upon balloon deflation, SEC lightens or disappears with increase in LAA flow velocity. [source] | ||||||||||||||||||||||