The Application and Teaching Value of a Ventricular Septal Defect Canine Model Established by Transcatheter Puncture.

This study aimed to improve and further explore a ventricular septal defect (VSD) canine model on the basis of the transcatheter puncture method and to evaluate its application and teaching value.In order to lessen the complications of VSD closure, it is necessary to improve the currently available treatment devices using appropriate animal models.In this study, we used 16 healthy adult canines as our models. After anesthesia, the VSD puncture was performed, followed by balloon dilatation of the perforation. VSD was confirmed by angiography. The venous-artery orbit was established, and the VSD was then closed once the catheter and occluder were across the defect.Of the experimental canines, 14 of the 16 canines were successfully modeled, giving a success rate of 87.5%. The canines underwent an immediate creation of a venous-artery orbit for teaching practice and were implanted with an occluder during the procedure. After 4 weeks, 13 canines survived. As per our findings, most VSD types established by the puncture were perimembranous (10 of 13, 77%).The current model has a high success rate. The model can not only avoid the risk of infection and hemodynamic disorders associated with an open thoracotomy, but can also be effectively used in evaluating the impact of occluders. It can also directly measure the parameters of the devices during the procedure, thus having a very high experimental and teaching value.

Outcomes and Complications of Lead Removal: Can We Establish a Risk Stratification Schema for a Collaborative and Effective Approach?

BACKGROUND: Removal of an entire cardiovascular implantable electronic device is associated with morbidity and mortality. We sought to establish a risk classification scheme according to the outcomes of transvenous lead removal in a single center, with the goal of using that scheme to guide electrophysiology lab versus operating room extraction. METHODS: Consecutive patients undergoing transvenous lead removal from January 2001 to October 2012 at Mayo Clinic were retrospectively reviewed. RESULTS: A total of 1,378 leads were removed from 652 (age 64 ± 17 years, M 68%) patients undergoing 702 procedures. Mean (standard deviation) lead age was 57.6 (58.8) months. Forty-four percent of leads required laser-assisted extraction. Lead duration (P < 0.001) and an implantable cardioverter defibrillator (ICD) lead (P < 0.001) were associated with the need for laser extraction and procedure failure (P < 0.0001 and P = 0.02). The major complication rate was 1.9% and was significantly associated with longer lead duration (odds ratio: 1.2, 95% confidence interval: 1.1-1.3; P < 0.001). High-risk patients (with a >10-year-old pacing or a >5-year-old ICD lead) had significantly higher major events than moderate-risk (with pacing lead 1-10 years old or ICD lead 1-5 years old) and low-risk (any lead ≤1-year-old) patients (5.3%, 1.2%, and 0%, respectively; P < 0.001). CONCLUSIONS: Transvenous lead removal is highly successful, with few serious procedural complications. We propose a risk stratification scheme that may categorize patients as low, moderate, and high risk for lead extraction. Such a strategy may guide which extractions are best performed in the operating room.

Outcomes of lead revision for myocardial perforation after cardiac implantable electronic device placement.

INTRODUCTION: Cardiac perforation is an infrequent but potentially life-threatening complication associated with placement of a cardiac implantable electronic device (CIED). The objective of this study was to determine the outcomes of percutaneous lead revision in patients who had lead perforation of the myocardium after CIED placement. METHODS AND RESULTS: We reviewed records of 1,458 patients who underwent CIED lead extraction or repositioning. Of these, 31 (2.1%) had the procedure performed for lead perforation as a complication of CIED placement. Demographic, clinical, and follow-up characteristics of the patients were analyzed. Mean (SD) patient age was 65 (23) years. Cardiac perforation was detected within 24 hours after implantation in 9 patients, within 1 month in 17, and greater than 1 month in 5. Pericardiocentesis was performed with a pigtail drainage catheter in place before the lead revision in 17 patients (55%) who had pericardial effusion, with or without hemodynamic compromise. All culprit leads were successfully managed with percutaneous lead removal (n = 3 [10%]), new lead placement (n = 12 [38%]), or lead repositioning (n = 16 [52%]). Of the 17 patients with pericardiocentesis before the reoperation, none had tamponade develop; in contrast, 3 of the remaining 14 patients had tamponade develop and required urgent pericardiocentesis. All patients survived without requiring open chest surgery. CONCLUSION: Percutaneous removal or repositioning of the perforating lead is feasible and appears effective. Placement of a prophylactic pericardial drain catheter may reduce the incidence of urgent pericardiocentesis during or after a procedure.

Symptomatic sinus tachycardia with perpetuating slow pathway: successful treatment with radiofrequency ablation.

We report a case of sinus tachycardia with perpetuating slow pathway (SP) conduction in a 42-year-old woman who developed severe symptoms as a result of atrioventricular (AV) desynchronization. The restoration of an AV synchrony, achieved with selective radiofrequency ablation of the SP, eliminated the symptomatic arrhythmia and may represent a reasonable therapeutic option despite the fact that the patient has no AV-node reentrant tachycardia. This case demonstrates the importance of AV timing.

Outcome and management of pacemaker-induced superior vena cava syndrome.

BACKGROUND: We aimed to determine the long-term outcomes of percutaneous lead extraction and stent placement in patients with pacemaker-induced superior vena cava (SVC) syndrome. METHODS: The study retrospectively screened patients who underwent lead extraction followed by central vein stent implantation at Mayo Clinic (Rochester, MN, USA), from January 2005 to December 2012, to identify the patients with pacemaker-induced SVC syndrome. Demographic, clinical, and follow-up characteristics of those patients were collected from electronic medical records. RESULTS: Six cases were identified. The mean (standard deviation) age was 56 (15) years (male, 67%). All patients had permanent dual-chamber pacemakers, with a mean 11-year history of pacemaker placement. The entire device system was explanted in five patients; one patient had a 21-year-old pacemaker lead that could not be removed. Eight stents were implanted in six patients: five patients had one stent, one patient had three. A new pacemaker system was reimplanted through the stented vein in five patients. Technical success was achieved in all patients, without any complication. Symptoms rapidly resolved in all patients after stent deployment. The mean follow-up duration was 48 months (range, 10-100 months). Three patients remained symptom free. Reintervention with percutaneous balloon venoplasty was successful in three patients with symptom recurrence. CONCLUSION: Percutaneous stent implantation after lead removal followed by reimplantation of leads is a feasible alternative therapy for pacemaker-induced SVC syndrome, although some cases may require repeat intervention.

Development and preclinical evaluation of a biodegradable ventricular septal defect occluder.

OBJECTIVES: This study evaluated the feasibility, effectiveness, and safety of a biodegradable (BD) occluder for closure of ventricular septal defect (VSD) in an acute canine model. BACKGROUND: All current available VSD occluders are permanent implants which consist of a metal framework and synthetic fabrics. However, the septal occluder in vivo plays the role of a temporary bridge that facilitates the ingrowth of fibrous connective tissue and endothelialization. The ideal occluder may be a temporary scaffold which can be gradually absorbed in vivo and replaced by "native" tissue. METHODS: The BD VSD occluder consists of a polydioxanone (PDO) framework and two pieces of poly-L-lactic acid (PLLA) fabrics. Percutaneous transcatheter closure of interventionally created VSDs was performed in 16 dogs using the BD occluders. Follow-up consisted of electrocardiography, transthoracic echocardiography, and fluoroscopy from 1 week to 24 weeks post-implantation. Gross pathology and histopathology were obtained at 6, 12, and 24 weeks follow-up. RESULTS: Implantation of the BD occluders was successful in 15 animals. The devices became well integrated into the ventricular septum with complete endothelialization at 12 weeks after implantation. After 24 weeks in vivo, the PDO framework of devices was largely absorbed and replaced by the ingrowth of collagenous fibers, and the PLLA fabric within disks was partly degraded. Neither occluder dislocation nor VSD recanalization occurred during follow-up. CONCLUSIONS: The BD occluder proved safe and effective for VSD closure. This device is characterized by compatible mechanical properties, a fully BD property, and a good match between the degradation of occluder and the healing response of organism.

Animal experimental study of the fully biodegradable atrial septal defect (ASD) occluder.

This study was conducted to evaluate the feasibility, safety, biocompatibility, and degradation features of a fully biodegradable occluder for closure of atrial septal defect (ASD) in an acute canine model. The ASD was created in 20 healthy mongrel dogs by the brockenbrough needle, and the fully biodegradable occluders were implanted by self-made delivery system. The success rate and complications were observed. Acute ASD models were successfully created in 18 dogs, and 16 occluders were successfully implanted in the ASD models. Animals were sacrificed at different times after procedure. The cardiac gross anatomy showed that all occluders were stable in the interatrial septum, no vegetation or thrombus formation was observed on the surface of all occluders. They were embedded into endogenous host tissue gradually at 12-week follow-up. Different periods of pathological observations suggested that the occluders degraded gradually over about 24 weeks and essentially became an integral part of the septum. Transcatheter closure of ASD in acute canine model using the fully biodegradable ASD occluder has the potential of a high successful rate of technique, excellent biocompatibility, and fewer complications with adequate, immediate, and short-term results.

Early diagnosis and rescue pericardiocentesis for acute cardiac tamponade during radiofrequency ablation for arrhythmias. Is fluoroscopy enough?

BACKGROUND: With the number of complex catheter ablation procedures increasing, procedure-related acute cardiac tamponade is encountered more frequently in the cardiac catheterization laboratory. Survival depends on prompt recognition and rescue pericardiocentesis. OBJECTIVE: The aim of this report was to validate fluoroscopic heart silhouette characteristics associated with cardiac tamponade as a diagnostic method, and evaluate the safety and effectiveness of fluoroscopy-guided pericardiocentesis during catheter ablation. METHODS: All cases of acute cardiac tamponade that occurred in the cardiac catheterization laboratory during radiofrequency catheter ablation from March 2004 to November 2009 were reviewed retrospectively. RESULTS: Of 1,832 catheter ablation procedures performed during a 5-year period, 10 (0.55%) were complicated by cardiac tamponade. Fluoroscopic examination confirmed the diagnosis in all 10 patients and demonstrated effusions before hypotension in four patients. All patients were stabilized by fluoroscopy-guided pericardiocentesis with placement of an indwelling catheter and autologous transfusion. The time interval between recognition of cardiac tamponade and completion of pericardiocentesis was 6.0 ± 1.8 minutes (range 3-9 minutes). The mean aspirated blood volume was 437 mL (range 110-1,400 mL), and the mean autotransfused blood volume was 425 mL (range 100-1,384 mL). Surgical repair of the cardiac perforation was needed in one patient. No procedure-related death occurred. CONCLUSION: A reduction in the excursion of cardiac silhouette on fluoroscopy is an early diagnostic sign of cardiac tamponade during radiofrequency ablation. Fluoroscopy-guided pericardiocentesis is a safe and effective management strategy for cardiac tamponade developed in the cardiac catheterization laboratory.

Safety and efficacy of transcatheter closure of large patent ductus arteriosus in adults with a self-expandable occluder.

Most occurrences of large patent ductus arteriosus (PDAs) of > or =10 mm have been surgically closed, and transcatheter closure of these large PDAs was only reported in a few case reports. The present study reviewed our experience in transcatheter closure of such large PDAs with a Chinese self-expandable occluder, which is similar to but much cheaper than the Amplatzer occluder. From July 2000 to January 2008, 23 patients underwent transcatheter closure of large PDA > or =10 mm with this kind of occluder. The mean (SD) age of the patients was 38.0 (15.6) years (range 18-75 years). Radiographs of the chest, electrocardiograms, and echocardiograms were used for follow-up evaluation of the treatment within 1 day, 1 month, 6 months, and then every year after successful closure. The mean (SD) angiographic PDA diameter was 12.8 (2.6) mm (range 10-18 mm) and the mean occluder diameter was 18.0 (2.9) mm (range 16-22 mm). The occluders were delivered successfully and closed the PDA completely in 19 out of the 23 patients. Pulmonary arterial pressures decreased significantly after occlusion in patients with successful treatment: 67.3 (24.7) mmHg (range 29-122 mmHg) before occlusion and 42.3 (22.0) mmHg (range 19-98 mmHg) immediately after the procedure. Radiographs of the chest and echocardiograms showed that the diameters of the left atrium, left ventricle, and the main pulmonary artery decreased, and the ejection fraction (EF) increased at a mean (SD) follow-up of 36.3 (18.7) months (range 6-72 months). No severe complication occurred. The immediate and long-term outcomes suggested that transcatheter closure of PDAs with the native PDA occluder is a safe and effective treatment for adults with large PDA > or =10 mm.

[Transcatheter pulmonary valve replacement in sheep: 6-month evaluation of self-expanding valved stents].

OBJECTIVE: The purpose of this study was to determine the feasibility of transcatheter pulmonary valve replacement in sheep up to 6 months post procedure. METHODS: Fresh sheep pericardium treated with a 0.6% glutaraldehyde solution for 36 hours was sutured to a valvular ring and then fixed onto a newly designed nitinol self-expandable stent. Thoracotomy was performed in sheep (23.5 +/- 3.1) kg under general anesthesia and the device was delivered into the native pulmonary valve of the sheep via the anterior wall of right ventricle by catheter and fooled for 6 months. RESULTS: One sheep died 4 months after the procedure due to in-stent thrombosis. Another 4 animals survived the 6-month observing period. Angiographic and hemodynamic measurements confirmed good positioning and function of the stents with a competent valve immediately post procedure and 6 months post the procedure in surviving animals. CONCLUSION: Implantation of the nitinol self-expandable stent in the pulmonary valve position by a transcatheter approach is feasible and good function of transcatheter implanted memory nitinol valved stents was shown after 6 months of implantation in sheep.

Outcomes of Transvenous Lead Extraction for Cardiovascular Implantable Electronic Device Infections in Patients With Prosthetic Heart Valves.

BACKGROUND: Lead-related or valve-related endocarditis can complicate cardiovascular implantable electronic device (CIED) infection in patients with both CIED and prosthetic valves. The objective of this study was to determine the outcomes of transvenous lead extraction for CIED infection in patients with prosthetic valves. METHODS AND RESULTS: We retrospectively screened 794 transvenous lead extraction procedures, between September 1, 2001 and August 31, 2012, at Mayo Clinic to identify patients with prosthetic valves who underwent lead extraction for infection. Demographic, clinical, and follow-up characteristics were analyzed. In total, 51 patients (6%) met the study inclusion criteria, of whom 20 had pocket infection and 31 had lead-related or valve-related, or both, endocarditis or bloodstream infection (mean age, 67 [18] years). Staphylococcal species were the most common pathogens, including Staphylococcus aureus in 20 cases (39%) and coagulase-negative staphylococci in 19 cases (37%). Overall, 127 transvenous leads (median lead age, 52 months) were extracted. Of these leads, 123 (97%) were removed completely. The in-hospital mortality rate was 9.8%; no deaths were attributable to the extraction procedure. Ninety-five percent of patients who survived had no evidence of recurrent device-related or valve-related infection. CONCLUSIONS: Transvenous lead extraction seems safe and curative in patients with CIED infection and prosthetic valves. Cure of infection can be achieved in the majority of patients with complete CIED removal and antimicrobial therapy and without valve surgery.

Extraction of superfluous device leads: A comparison with removal of infected leads.

BACKGROUND: Although increasingly more lead extraction was performed for superfluous leads, the extraction of such leads remains controversial. OBJECTIVE: The objective of this study was to determine the outcomes and complications of transvenous extraction of superfluous leads in a single center in the era of laser technology. METHODS: Four hundred eighty transvenous lead extraction procedures performed from January 2001 through October 2012 at Mayo Clinic (Rochester, Minnesota) were retrospectively reviewed. Of these, 123 procedures were performed for superfluous functional or nonfunctional leads. Data were collected from electronic medical records and an institutional database of cardiovascular implantable electronic devices. RESULTS: A total of 167 superfluous leads (mean [SD] lead duration 53 [53] months; median 34 months) were removed during the 123 procedures. Forty-one percent of procedures were for lead malfunction. The procedural complete-success rate was 96.7%. Major complications occurred in 1 patient (0.8%), who had a superior vena cava tear that required thoracotomy. Superfluous leads had been implanted for a shorter period of time than infected leads (mean [SD] 53 [53] vs 81 [59] months; P < .001). The procedural complete-success rate was higher for the removal of superfluous leads than for leads associated with infection (97% vs 92%; P = .05). CONCLUSION: Transvenous extraction of superfluous leads is highly successful, with few procedural complications. Extraction of superfluous leads at the time of device upgrade or lead revision is considered reasonable to avoid the increasing risk of extraction complications with lead aging.

Relative efficacy of catheter ablation vs antiarrhythmic drugs in treating premature ventricular contractions: a single-center retrospective study.

BACKGROUND: It is unknown whether radiofrequency ablation (RFA) or antiarrhythmic therapy is superior when treating patients with symptomatic premature ventricular contractions (PVCs). OBJECTIVE: To determine the relative efficacy of RFA and antiarrhythmic drugs (AADs) on PVC burden reduction and increasing left ventricular systolic function. METHODS: Patients with frequent PVCs (>1000/24 h) were treated either by RFA or with AADs from January 2005 through December 2010. Data from 24-hour Holter monitoring and echocardiography before and 6-12 months after treatment were compared between the 2 groups. RESULTS: Of 510 patients identified, 215 (40%) underwent RFA and 295 (60%) received AADs. The reduction in PVC frequency was greater by RFA than with AADs (-21,799/24 h vs -8,376/24 h; P < .001). The left ventricular ejection fraction (LVEF) was increased significantly after RFA (53%-56%; P < .001) but not after AAD (52%- 52%; P = .6) therapy. Of 121 (24%) patients with reduced LVEF, 39 (32%) had LVEF normalization to 50% or greater. LVEF was restored in 25 of 53 (47%) patients in the RFA group compared with 14 of 68 (21%) patients in the AAD group (P = .003). PVC coupling interval less than 450 ms, less impaired left ventricular function, and RFA were independent predictors of LVEF normalization performed by using multivariate analysis. CONCLUSION: RFA appears to be more effective than AADs in PVC reduction and LVEF normalization.

Plasma ghrelin and obestatin levels are increased in spontaneously hypertensive rats.

Obestatin, encoded by the same gene as ghrelin, was first described as a physiological opponent of ghrelin. We investigated fasting plasma ghrelin and obestatin levels in spontaneously hypertensive rats and Wistar-Kyoto rats. We found that ghrelin levels, obestatin levels and the ratio of ghrelin to obestatin were significantly higher in spontaneously hypertensive rats than Wistar-Kyoto rats. Systolic blood pressure and diastolic blood pressure were positively correlated; however, heart period and baroreflex sensitivity were negatively correlated with ghrelin levels. Systolic blood pressure was positively correlated, whereas baroreflex sensitivity was negatively correlated with obestatin levels. In addition, systolic blood pressure was a significantly independent variable of ghrelin levels, obestatin levels, and the ghrelin to obestatin ratio in a multiple regression analysis. Our data suggests that there is a disturbance of ghrelin and obestatin in the circulation of spontaneously hypertensive rats and the ghrelin/obestatin system might play a role in blood pressure regulation.