Incorporating a companion test into the noninferiority design of medical device trials.

Noninferiority trials are commonly utilized to evaluate the safety and effectiveness of medical devices. It could happen that the noninferiority hypothesis is rejected while the performance of the active control is clinically not satisfactory. This may pose a great challenge when making a regulatory decision. To avoid such a difficult situation, we propose to conduct a companion test to assess the performance of the active control when testing the main noninferiority hypothesis and to incorporate such a test into the study design. Under our proposal, the noninferiority of the investigational device to the active control can only be claimed when both hypotheses are rejected. The operating characteristics of the proposed study design based on these two tests can be fully evaluated at the design stage. This proposed approach is aimed to facilitate regulatory decision making in a more transparent manner.

Radiofrequency catheter ablation of atrial fibrillation: Electrical modification suggesting transmurality is faster achieved with remote magnetic catheter in comparison with contact force use.

BACKGROUND: Remote magnetic navigation (RMN) and contact force (CF) sensing catheters are available technologies for radiofrequency (RF) catheter ablation of atrial fibrillation (AF). Our purpose was to compare time to electrogram (EGM) modification suggesting transmural lesions between RMN and CF-guided AF ablation. METHODS AND RESULTS: A total of 1,008 RF applications were analyzed in 21 patients undergoing RMN (n = 11) or CF-guided ablation (n = 10) for paroxysmal AF. All procedures were performed in sinus rhythm during general anesthesia. Time to EGM modification was measured until transmurality criteria were fulfilled: (1) complete disappearance of R if initial QR morphology; (2) diminution > 75% of R if initial QRS morphology; (3) complete disappearance of R' of initial RSR' morphology. Impedance drop as well as force time integral (FTI) were also assessed for each application. Mean CF at the beginning of each RF application in the CF group was 11 ± 2 g and mean FTI per application was 488 ± 163 gs. Time to EGM modification was significantly shorter in the RMN group (4.52 ± 0.1 seconds vs. 5.6 ± 0.09 seconds; P < 0.00001). There was no significant difference between other procedural parameters. CONCLUSION: Remote magnetic AF ablation is associated with faster EGM modification suggesting transmurality than optimized CF and FTI-guided catheter ablation.

Guidewire and microcatheter utilization patterns during antegrade wire escalation in chronic total occlusion percutaneous coronary intervention: Insights from a contemporary multicenter registry.

OBJECTIVES: We sought to describe contemporary guidewire and microcatheter utilization for antegrade wire escalation (AWE) during chronic total occlusion (CTO) percutaneous coronary intervention (PCI). BACKGROUND: Equipment utilization for AWE has been variable and evolving over time. METHODS: We examined device utilization during 694 AWE attempts in 679 patients performed at 15 experienced US centers between May 2012 and April 2015. RESULTS: Mean age was 65.6 ± 9.7 years, and 85% of the patients were men. Successful wiring occurred in 436 AWE attempts (63%). Final technical and procedural success was 91% and 89%, respectively. The mean number of guidewire types used for AWE was 2.2 ± 1.4. The most frequently used guidewire types were the Pilot 200 (Abbott Vascular, 56% of AWE procedures), Fielder XT (Asahi Intecc, 45%), and the Confianza Pro 12 (Asahi Intecc, 28%). The same guidewires were the ones that most commonly crossed the occlusion: Pilot 200 (36% of successful AWE crossings), Fielder XT (20%), and Confianza Pro 12 (11%). A microcatheter or over-the-wire balloon was used for 81% of AWE attempts; the Corsair microcatheter (Asahi Intecc) was the most commonly used (44%). No significant association was found between guidewire type and incidence of major adverse cardiac events (MACE). CONCLUSIONS: Our contemporary, multicenter CTO PCI registry demonstrates that the most commonly used wires for AWE are polymer-jacketed guidewires. "Stiff" and polymer-jacketed guidewires appear to provide high crossing rates without an increase in MACE or perforation, and may thus be considered for upfront use. © 2016 Wiley Periodicals, Inc.

Cryoablation with an 8-mm-Tip Catheter for Right-Sided Accessory Pathways in Children.

BACKGROUND: Cryoablation is increasingly utilized in children because of its safety profile. Recently, larger catheter tips have been more widely used to improve long-term success rates. The aim of this study was to assess the safety and efficacy of 8-mm-tip catheters for cryoablation of right-sided accessory pathways (APs) in children. METHODS: Electrophysiological procedures were performed using the EnSite™ system (St. Jude Medical Inc., St. Paul, MN, USA). RESULTS: Between July 2010 and July 2014, 54 patients (mean age: 13.1 ± 3.7 years) underwent cryoablation using an 8-mm-tip catheter. In 18 of 54 (33%) patients where an 8-mm-tip catheter was the first-choice catheter, the success rate was 18 of 18 (100%). There was a history of previous failed attempts or recurrence with radiofrequency ablation and/or 6-mm-tip cryoablation in 36 of 54 (67%) patients. The success rate in these patients was 24 of 36 (67%). No fluoroscopy was used in 34 of 54 procedures. The recurrence rate was six of 42 (14%) during a mean follow-up period of 32 ± 15 months. In one patient, transient atrioventricular block occurred. CONCLUSIONS: Cryoablation with an 8-mm-tip catheter for right-sided APs in children who weigh over 40 kg appears to be safe and acutely effective in cases where conventional ablation methods fail and also as a first choice for ablation procedure. However, the recurrence rate still seems to be high.

Safety and efficacy of second-generation versus first-generation cryoballoons for treatment of atrial fibrillation: a meta-analysis of current evidence.

BACKGROUND: The newer second-generation cryoballoons (CB-2 or Arc-Adv-CB) have been shown to achieve significantly lower temperature and faster pulmonary vein isolation (PVI) time in comparison with first-generation cryoballoons (CB-1 or Arc-CB). To test the premise that second-generation cryoballoons can improve clinical outcomes in comparison to first-generation cryoballoons in terms of safety and efficacy, we pooled data for systemic review and meta-analyses from all available literature comparing their clinical performance. METHODS: The Cochrane Library, PubMed, Google Scholar, and studies presented at various meetings were searched for any published literature comparing safety and efficacy of the second-generation cryoballoons (Arctic Front Advance cryoballoons) with first-generation cryoballoons (Arctic Front Cryoballoons). A total of ten published studies, with 2310 patients, were included in this meta-analysis with 957 patients in second-generation cryoballoon group and 1237 patients in first-generation cryoballoon group. RESULTS: The pooled analysis showed significant superiority of second-generation cryoballoons in terms of less procedure time, less fluoroscopic time, and fewer incidences of arrhythmia recurrences compared to first-generation cryoballoons at the cost of higher incidence of persistent and transient phrenic nerve palsy. The differences in the rate of pericardial effusion and incidence of access site complications were not statistically significant. CONCLUSIONS: Second-generation cryoballoons are associated with a shorter procedure time and fluoroscopy time, along with lower arrhythmia recurrence rates, reflecting higher procedure efficacy when compared to first-generation cryoballoons. However, they are also associated with a higher incidence of transient and persistent phrenic nerve palsies with a non-significant difference in rates of access site complications and pericardial effusion.

Same-day cardiac catheter ablation is safe and cost-effective: Experience from a UK tertiary center.

BACKGROUND: Catheter ablation is a curative intervention for common arrhythmias such as supraventricular tachycardia and atrial flutter. Many centers still admit patients overnight after this procedure. OBJECTIVE: This study was performed to evaluate the safety and cost-effectiveness of same-day standard catheter ablation. METHODS: We conducted a retrospective study of all consecutive elective same-day procedures performed between 2010 and 2014. Data were collected on baseline parameters, procedure details and success, postoperative complications, unplanned overnight hospital admissions, and clinical outcome (including mortality) at 4-month follow-up. A cost analysis of potential savings was also performed. RESULTS: A total of 1142 patients underwent planned same-day electrophysiological study with or without ablation. Radiofrequency ablation was performed in 897 of these patients (mean age ± standard error 56 ± 0.6 years, range 16-95 years, 467 males), with 921 arrhythmias ablated and with complete procedural success in 883 cases (96%). There were 92 unplanned admissions (10.3%): 50 for concealed pathways that required transseptal puncture, 19 for immediate complications (including 9 femoral bleeds and 5 pacemakers for heart block), 12 admitted at the operator's discretion, and 11 for other clinical reasons. All had transthoracic echocardiography after the procedure, and none had significant pericardial effusion. At 4-month follow-up, there were 16 readmissions (1 deep vein thrombosis, 3 pericarditic chest pain, 2 femoral hematomas, 7 palpitations, and 3 others) and 1 death (unrelated to ablation). An overnight stay at our center costs $450 (£300); same-day ablation over this period saved our institution $365,000 (£240,000). CONCLUSION: Same-day standard catheter ablation is safe and cost-effective, with significant benefits for patients and health care providers. This is particularly important given the current financial climate.

Usefulness of Corsair microcatheter to cross stent struts in bifurcation lesions.

Side branch compromise after stenting in bifurcation lesions is a matter of concern. It may happen that even low-profile balloon catheters do not cross stent struts after rewiring. The Corsair catheter is a hybrid catheter that has features of a microcatheter and a support catheter. The present study evaluated usefulness of the Corsair catheter to facilitate advancing a low-profile balloon catheter through stent struts in bifurcation lesions. After rewiring, low-profile balloon catheters failed to cross stent struts of 29 bifurcation lesions. The Corsair microcatheter successfully crossed stent struts in all lesions except one (97 %) where a stent was implanted to treat in-stent restenosis (stent-in-stent). Low-profile balloon catheters were able to advance into the side branch of all bifurcation lesions where the Corsair microcatheter crossed stent struts. In conclusion, the Corsair microcatheter may be utilized if low-profile balloon catheters are unable to cross stent struts in bifurcation lesions.

Device size for transcatheter closure of ovoid interatrial septal defect.

BACKGROUND: For successful transcatheter closure of an atrial septal defect with the Amplatzer septal occluder, the shape of the defect should be considered before selecting the device size. The purpose of this study was to evaluate the results of transcatheter closure of an ovoid atrial septal defect. METHODS: Between January 2010 and February 2012, cardiac computer tomography examinations were performed in 78 patients who subsequently underwent transcatheter closure of an atrial septal defect. In this retrospective study, we reviewed these patients' medical records. We defined an ovoid atrial septal defect as a value of 0.75 for the ratio of the shortest diameter of the defect to the longest diameter, as measured in a computed tomography image. Transthoracic echocardiography examinations were made at 1 day and 6 months after the procedure. RESULTS: Transcatheter closure of an atrial septal defect was successful in 26 patients in the ovoid-defect group and in 52 patients in the round-defect group. There were no serious complications in either group, and the rate of complete closure at 6 months was 92.3% in the ovoid-defect group and 93.1% in the round-defect group (P > .05). The mean (SD) difference between the device size and the defect's longest diameter, and the mean ratio of the device size to the longest diameter were significantly smaller in the ovoid-defect group (1.7 ± 2.9 versus 3.8 ± 2.5 and 1.1 ± 0.1 versus 1.3 ± 0.2, respectively). CONCLUSIONS: Transcatheter closure of an atrial septal defect is indicated even for an ovoid atrial septal defect. Ovoid atrial septal defects can be closed successfully with smaller sizes of the Amplatzer septal occluder than for round atrial septal defects.

Variation in radiographic protocols in paediatric interventional cardiology.

The aim of this work is to determine current radiographic protocols in paediatric interventional cardiology (IC) in the UK and Ireland. To do this we investigated which imaging parameters/protocols are commonly used in IC in different hospitals, to identify if a standard technique is used and illustrate any variation in practice. A questionnaire was sent to all hospitals in the UK and Ireland which perform paediatric IC to obtain information on techniques used in each clinical department and on the range of clinical examinations performed. Ethical and research governance approval was sought from the Office for Research Ethics Committees Northern Ireland and the individual trusts. A response rate of 79% was achieved, and a wide variation in technique was found between hospitals. The main differences in technique involved variations in the use of an anti-scatter grid and the use of additional filtration to the radiation beam, frame rates for digital acquisition and pre-programmed projections/paediatric specific programming in the equipment. We conclude that there is no standard protocol for carrying out paediatric IC in the UK or Ireland. Each hospital carries out the IC procedure according to its own local protocols resulting in a wide variation in radiation dose.

Benefit to decrease esophageal damage using an ablation catheter with increased irrigation channels for pulmonary vein isolation.

INTRODUCTION: An ablation catheter has been developed with six additional irrigation channels at the proximal end of the ablating electrode. We investigated the potential improvement of esophageal damage when the number of irrigation channels of the ablation catheter was increased during pulmonary vein isolation (PVI). METHODS: This study included a total of 296 consecutive patients with atrial fibrillation. One hundred forty-eight patients were randomly assigned to receive PVI using an ablation catheter with six distal irrigation channels (6C) and 148 patients to receive PVI using an ablation catheter with 12 distal irrigation channels (12C). The luminal esophageal temperature (LET) was monitored in all patients. RESULTS: A total of 639 radiofrequency energy applications (in 225 out of 296 patients) reached the cut-off temperature. The time for the LET to reach the cut-off temperature was shorter for the 6C than the 12C group, and the 6C group had a higher T max of the LET than the 12C group. Some patients experienced a transient drop in the LET (TDLET) just before the delivery of the energy. The site that caused a TDLET before the energy delivery always reached the cut-off temperature. TDLET was more frequent in the 6C group than in the 12C group. CONCLUSIONS: The LET only showed a small difference between the 6C and 12C groups. In contrast, there may be a lower risk of esophageal injury with the 6C than the 12C if we use TDLET.

Impact of using a telescoping-support catheter system for left ventricular lead placement on implant success and procedure time of cardiac resynchronization therapy.

BACKGROUND: Proper positioning of the left ventricular (LV) lead improves clinical outcomes and survival in patients receiving cardiac resynchronization therapy (CRT). Techniques of LV lead insertion using contrast injection and a telescoping system of delivery catheters to support advancement of the lead into the target branch may allow more efficient, targeted lead placement. We sought to evaluate the impact of an LV lead implant approach using telescoping-support catheters (group TS) on success rate, lead location, and procedural time compared to standard over-the-wire implant techniques (group OTW). METHODS: Four hundred thirty-seven consecutive patients undergoing CRT implantation were divided into group TS (n = 105) or group OTW (n = 332) based upon a review of the operative technique used for LV lead implantation. The primary outcome was success of LV lead implantation at the index procedure. Secondary endpoints included optimal positioning of the LV lead and reduction in procedural fluoroscopy time. RESULTS: Failed LV lead placement was lower (1.9% vs 8.1%, P = 0.02) and optimal lead positioning was achieved more often for group TS than group OTW (87% vs 75%, P = 0.01). In addition, there were significantly shorter fluoroscopy times for group TS versus group OTW (29.6 minutes vs 41.9 minutes, P < 0.01). CONCLUSION: A CRT-implant approach using contrast injection and a telescoping-support catheter system results in fewer failed LV lead implants, improved LV lead location, and shorter procedure times.