Faculty Bibliography

Spontaneous spinal epidural hematoma is an extraordinarily rare condition for which there are only a few hundred documented cases, none in relation to cardiac ablation procedures. This case describes a 71-year-old woman who develops lower extremity numbness and weakness due to spontaneous spinal epidural hematoma after an atrial fibrillation ablation. (Level of Difficulty: Intermediate.).

Beta-blockers are typically prescribed following myocardial infarction (MI), but no specific beta-blocker is recommended. Of 7,057 patients enrolled in the OBTAIN multi-center registry of patients with acute MI, 4142 were discharged on metoprolol and 1487 on carvedilol. Beta-blocker dose was indexed to the target daily dose used in randomized clinical trials (metoprolol-200 mg; carvedilol-50 mg), reported as %. Beta-blocker dosage groups were >0%-12.5% (n=1428), >12.5%-25% (n=2113), >25%-50% (n=1392), and >50% (n=696). The Kaplan-Meier method was used to calculate three-year survival. Correction for baseline differences was achieved by multivariable adjustment. Patients treated with carvedilol were older (64.4 versus 63.3 years) and had more comorbidities: hypertension, diabetes, prior MI, congestive heart failure, reduced left ventricular ejection fraction, and a longer length of stay. Mean doses for metoprolol and carvedilol did not significantly differ (37.2±27.8% and 35.8±31.0%, respectively). The 3-year survival estimates were 88.2% and 83.5% for metoprolol and carvedilol, respectively, with an unadjusted HR=0.72 (p<0.0001), but after multivariable adjustment HR=1.073 (p=0.43). Patients in the >12.5-25% dose category had improved survival compared to other dose categories. Subgroup analysis of patients with left ventricular ejection fraction ≤40%, showed worse survival with metoprolol versus carvedilol (adjusted HR=1.281; 95% CI: 1.024-1.602, p=0.03). In patients with left ventricular ejection fraction >40%, there were no differences in survival with carvedilol versus metoprolol. In conclusion, overall survival after acute MI was similar for patients treated with metoprolol or carvedilol, but may be superior for carvedilol in patients with left ventricular ejection fraction ≤40%.

OBJECTIVES/OBJECTIVE:The aim of this study was to determine the differences in lead failure mechanisms across the major United States implantable defibrillator lead manufacturers (Boston Scientific, Medtronic, and St. Jude Medical), between all non-recalled and recalled leads, and between two recalled lead families (Medtronic Sprint Fidelis and the St. Jude Medical Riata and Riata ST). METHODS:This was a single-center, non-randomized, retrospective study analyzing 3802 patients with 4078 leads who underwent implantable defibrillator lead implantation between February 1, 1996 and December 31, 2011. Lead failure mechanisms were defined as lead fracture, insulation defect, and other. RESULTS:A total of 153 leads (3.8%) failed during the trial period. Failed Medtronic and St. Jude Medical leads presented predominantly as lead fractures (75.8% and 52.8%, respectively). Failed Boston Scientific leads displayed greater variability, although many also failed by fracture (44.4%). The majority of failed non-recalled and recalled leads presented as fractures (50.7% and 82.9%, respectively). The recalled Medtronic Sprint Fidelis and St. Jude Medical Riata/Riata ST leads primarily presented as fractures (89.3% and 65.0%, respectively). Patients whose lead failed via an insulation defect or other mechanism appeared to have a faster time to mortality following lead failure than patients whose lead failed via fracture (P<.01 and P=.02, respectively). CONCLUSIONS:Lead fracture is the most common form of lead failure regardless of the failure points previously identified in these leads. Patients who experienced a lead failure as a result of an insulation defect or other mechanism appeared to die faster than patients whose lead failed via fracture.

OBJECTIVES/OBJECTIVE:The purpose of this study was to investigate the relationship between operator volume and implantable defibrillator lead failure and patient mortality at a single large implanting center. METHODS:This study analyzed the differences between high-volume and low-volume defibrillator implanters in the Pacemaker and Implantable Defibrillator Lead Survival Study ("PAIDLESS") between February 1, 1996 and December 31, 2011 at NYU Winthrop Hospital. "High-volume" was defined as performing ≥500 implants over the study period, while "low-volume" was defined as performing <500 implants. Comparisons between the procedure volume groups were performed using Fisher's Exact test, Wilcoxon rank-sum test, and Kaplan-Meier analysis as appropriate. RESULTS:Eight operators participated in the study, four of whom were high-volume operators. Of 3801 patients, a total of 3149 (83%) were operated upon by high-volume operators. Low-volume operators implanted fewer recalled leads (12% vs 42%; P<.001) and more often obtained venous access through the cephalic vein cutdown approach (63% vs 38%; P<.001) than high-volume operators. Kaplan-Meier analysis revealed shorter time to lead failure in the low-volume group (P=.02). Time to mortality was not significantly different between the high-volume and low-volume groups (P=.18). When adjusted for lead recall status, patients of high-volume operators were 43% less likely to experience lead failure compared to patients of low-volume operators. CONCLUSIONS:High-volume defibrillator implanters selected a higher percentage of recalled leads, but their patients were less likely to encounter lead failure when adjusted for lead recall status compared to low-volume operators.

OBJECTIVES/OBJECTIVE:The purpose of this study was to determine if implantation of multiple recalled defibrillator leads is associated with an increased risk of lead failure. BACKGROUND:The authors of the Pacemaker and Implantable Defibrillator Leads Survival Study ("PAIDLESS") have previously reported a relationship between recalled lead status, lead failure, and patient mortality. This substudy analyzes the relationship in a smaller subset of patients who received more than one recalled lead. The specific effects of having one or more recalled leads have not been previously examined. METHODS:This study analyzed lead failure and mortality of 3802 patients in PAIDLESS and compared outcomes with respect to the number of recalled leads received. PAIDLESS includes all patients at Winthrop University Hospital who underwent defibrillator lead implantation between February 1, 1996 and December 31, 2011. Patients with no recalled ICD leads, one recalled ICD lead, and two recalled ICD leads were compared using the Kaplan-Meier method and log-rank test. Sidak adjustment method was used to correct for multiple comparisons. All calculations were performed using SAS 9.4. P-values <.05 were considered statistically significant. RESULTS:This study included 4078 total ICD leads implanted during the trial period. There were 2400 leads (59%) in the no recalled leads category, 1620 leads (40%) in the one recalled lead category, and 58 leads (1%) in the two recalled leads category. No patient received more than two recalled leads. Of the leads categorized in the two recalled leads group, 12 experienced lead failures (21%), which was significantly higher (P<.001) than in the no recalled leads group (60 failures, 2.5%) and one recalled lead group (81 failures; 5%). Multivariable Cox's regression analysis found a total of six significant predictive variables for lead failure including the number of recalled leads (P<.001 for one and two recalled leads group). CONCLUSIONS:The number of recalled leads is highly predictive of lead failure. Lead-based multivariable Cox's regression analysis produced a total of six predictive variable categories for lead failure, one of which was the number of recalled leads. Kaplan-Meier analysis showed that the leads in the two recalled leads category failed faster than both the no recalled lead and one recalled lead groups. The greater the number of recalled leads to which patients are exposed, the greater the risk of lead failure.

OBJECTIVES/OBJECTIVE:The purpose of this study was to investigate the influences of gender and age on defibrillator lead failure and patient mortality. BACKGROUND:The specific influences of gender and age on defibrillator lead failure have not previously been investigated. METHODS:This study analyzed the differences in gender and age in relation to defibrillator lead failure and mortality of patients in the Pacemaker and Implantable Defibrillator Leads Survival Study ("PAIDLESS"). PAIDLESS includes all patients at Winthrop University Hospital who underwent defibrillator lead implantation between February 1, 1996 and December 31, 2011. Male and female patients were compared within each age decile, beginning at 15 years old, to analyze lead failure and patient mortality. Statistical analyses were performed using Wilcoxon rank-sum test, Fisher's exact test, Kaplan-Meier analysis, and multivariable Cox regression models. P<.05 was considered statistically significant. No correction for multiple comparisons was performed for the subgroup analyses. RESULTS:A total of 3802 patients (2812 men and 990 women) were included in the analysis. The mean age was 70 ± 13 years (range, 15-94 years). Kaplan-Meier analysis found that between 45 and 54 years of age, leads implanted in women failed significantly faster than in men (P=.03). Multivariable Cox regression models were built to validate this finding, and they confirmed that male gender was an independent protective factor of lead failure in the 45 to 54 years group (for male gender: HR, 0.37; 95% confidence interval, 0.14-0.96; P=.04). Lead survival time for women in this age group was 13.4 years (standard error, 0.6), while leads implanted in men of this age group survived 14.7 years (standard error, 0.3). Although there were significant differences in lead failure, no differences in mortality between the genders were found for any ages or within each decile. CONCLUSIONS:This study is the first to compare defibrillator lead failure and patient mortality in relation to gender and age deciles at a single large implanting center. Within the 45 to 54 years group, leads implanted in women failed faster than in men. Male gender was found to be an independent protective factor in lead survival. This study emphasizes the complex interplay between gender and age with respect to implantable defibrillator lead failure and mortality.

OBJECTIVES/OBJECTIVE:The purpose of the study was to examine survival in the implantable defibrillator subset of implanted leads at a large-volume implanting hospital. BACKGROUND:Implantable lead survival has been the subject of many multicenter studies over the past decade. Fewer large implanting volume single-hospital studies have examined defibrillator lead failure as it relates to patient survival and lead construction. METHODS:This investigator-initiated retrospective study examined defibrillator lead failure in those who underwent implantation of a defibrillator between February 1, 1996 and December 31, 2011. Lead failure was defined as: failure to capture/sense, abnormal pacing and/or defibrillator impedance, visual insulation defect or lead fracture, extracardiac stimulation, cardiac perforation, tricuspid valve entrapment, lead tip fracture and/or lead dislodgment. Patient characteristics, implant approach, lead manufacturers, lead models, recalled status, patient mortality, and core lead design elements were compared using methods that include Kaplan Meier analysis, univariate and multivariable Cox regression models. RESULTS:A total of 4078 defibrillator leads were implanted in 3802 patients (74% male; n = 2812) with a mean age of 70 ± 13 years at Winthrop University Hospital. Lead manufacturers included: Medtronic: [n = 1834; 801 recalled]; St. Jude Medical: [n = 1707; 703 recalled]; Boston Scientific: [n = 537; 0 recalled]. Kaplan-Meier analysis adjusted for multiple comparisons revealed that both Boston Scientific's and St. Jude Medical's leads had better survival than Medtronic's leads (P<.001 and P=.01, respectively). Lead survival was comparable between Boston Scientific and St. Jude Medical (P=.80). A total of 153 leads failed (3.5% of all leads) during the study. There were 99 lead failures from Medtronic (5.4% failure rate); 56 were recalled Sprint Fidelis leads. There were 36 lead failures from St. Jude (2.1% failure rate); 20 were recalled Riata or Riata ST leads. There were 18 lead failures from Boston Scientific (3.35% failure rate); none were recalled. Kaplan Meier analysis also showed lead failure occurred sooner in the recalled leads (P=.01). A total of 1493 patients died during the study (mechanism of death was largely unknown). There was a significant increase in mortality in the recalled lead group as compared with non-recalled leads (P=.01), but no significant difference in survival when comparing recalled leads from Medtronic with St. Jude Medical (P=.67). A multivariable Cox regression model revealed younger age, history of percutaneous coronary intervention, baseline rhythm other than atrial fibrillation or atrial flutter, combination polyurethane and silicone lead insulation, a second defibrillation coil, and recalled lead status all contributed to lead failure. CONCLUSION/CONCLUSIONS:This study demonstrated a significantly improved lead performance in the Boston Scientific and St. Jude leads as compared with Medtronic leads. Some lead construction variables (insulation and number of coils) also had a significant impact on lead failure, which was independent of the manufacturer. Recalled St. Jude leads performed better than recalled Medtronic leads in our study. Recalled St. Jude leads had no significant difference in lead failure when compared with the other manufacturer's non-recalled leads. Defibrillator recalled lead status was associated with an increased mortality as compared with non-recalled leads. This correlation was independent of the lead manufacturer and clinically significant even when considering known mortality risk factors. These results must be tempered by the largely unknown mechanism of death in these patients.

BACKGROUND:Radiofrequency (RF) catheter ablation has provided an effective method for treating drug-refractory symptomatic atrial fibrillation. Recently, a cryoablation balloon approach has also received approval. The purpose of this study was to compare RF catheter ablation to cryoablation for the treatment of atrial fibrillation with respect to safety, immediate efficacy, and effects on procedural and fluoroscopy times. In addition, actual procedural costs were compared. METHODS:This study was approved by the Winthrop University Hospital Institutional Review Board to retrospectively examine cryoablation with the Arctic Front Cardiac CryoAblation balloon catheter (Medtronic, Inc) and compare it to RF catheter ablation for the treatment of drug-refractory symptomatic atrial fibrillation. Patient and procedural characteristics as well as immediate success were compared. Immediate failure was defined as incomplete pulmonary vein isolation of all veins. RESULTS:A total of 124 procedures (62 RFs and 62 cryoablations) were performed from December 2010 through July 2012. The cryoablation procedure took longer to perform than RF (171 ± 61 minutes vs 126 ± 49 minutes, respectively; P<.0001). There was no difference in fluoroscopy times between the two groups (29 ± 20 minutes for RF vs 32 ± 18 minutes for cryoablation; P=.39). The infusion of protamine following procedures was much more common in the cryoablation group (30 patients vs 2 patients in the RF group; P<.0001). The immediate success rate was 93.5% with RF ablation vs 96.7% with cryoablation (P=NS). There was not a significant difference in complications between the two approaches. The cost for each procedure was $24,391.88 ± 4826.77 for RF and $31,874.02 ± 8349.70 for cryoablation (P<.0001). CONCLUSION/CONCLUSIONS:Cryoablation provides an additional and alternative approach to RF ablation for the treatment of symptomatic drug-refractory atrial fibrillation with comparable immediate success and complications. It is synergistic with RF and permits the ability to tackle the entire gamut of atrial fibrillation (ie, paroxysmal and persistent). This study showed no decrease in procedural or fluoroscopy times with our early experience. One significant limitation with cryoablation is the cost. Cryoablation resulted in over $7000 extra cost to the hospital per procedure. The clinical benefits achieved by this additional cost warrant further investigation.