Sudden cardiac arrest in end-stage renal disease patients on dialysis: A nationwide study.

BACKGROUND: Sudden cardiac arrest (SCA) is frequently encountered in end-stage renal disease (ESRD) patients on dialysis. There is a dearth of national data on SCA-associated outcomes in this specific patient population. The aim of the present study is to study these parameters from a nationally representative US population. METHODS: Data were extracted from National Inpatient Sample database from October 2005 to December 2014. All patients with clinical encounter of dialysis during the study period were enrolled. Patients who underwent SCA, ventricular fibrillation, ventricular tachycardia, and ventricular flutter were then identified by applying relevant International Classification of Diseases, Ninth Revision, Clinical Modification codes. Patients with acute kidney injury and prior renal transplant were excluded. Propensity matching was done to balance covariates among study groups. Logistic regression analysis was done to assess for predictors of SCA-associated mortality in ESRD patients on dialysis. RESULTS: A total of 1 147 760 patients were included in the final analyses. Patients who suffered SCA were older when compared to the non-SCA cohort and had a higher burden of comorbidities. About half (52.10%) of ESRD patients who suffered SCA died. Advanced age, metabolic acidosis, and cardiogenic shock were independently associated with reduced survival after SCA. New implantable cardioverter defibrillator implantation continues to be low in this patient population at discharge. CONCLUSION: SCA in settings of ESRD on dialysis carries high mortality and frequent morbidity. Further research in therapeutic interventions that could prevent SCA in this vulnerable population is utmost needed.

Battery longevity from cardiac resynchronization therapy defibrillators: differences between manufacturers and discrepancies with published product performance reports.

AIMS: Cardiac resynchronization therapy (CRT) is an important treatment for heart failure that requires constant ventricular pacing, placing a high energy burden on CRT defibrillators (CRT-D). Longer battery life reduces the need for device changes and associated complications, thereby affecting patient outcomes and cost of care. We therefore investigated the time to battery depletion of CRT-D from different manufacturers and compared these results with manufacturers' published product performance reports (PPRs). METHODS AND RESULTS: All CRT-D recipients at our institution between January 2008 and December 2010 were included in this study cohort. The patients were followed up to the endpoint of battery depletion and were otherwise censored at the time of death, last follow-up, or device removal for any reason other than battery depletion. A total of 621 patients [173 Boston Scientific (BSC), 391 Medtronic (MDT), and 57 St. Jude Medical (SJM)] were followed up for a median of 3.7 (IQR 1.6-5.0) years, during which time 253 (41%) devices were replaced for battery depletion. Compared with MDT devices, battery depletion was 85 and 54% less likely to happen with BSC and SJM devices, respectively (P < 0.001 for pairwise comparisons). Product performance reports from all manufacturers significantly overestimated battery longevity by more than 20% 6 years after device implantation. CONCLUSIONS: Large differences in CRT-D battery longevity exist between manufacturers. Industry-published PPRs significantly overestimate device longevity. These data have important implications to patients, healthcare professionals, hospitals, and third-party payers.

Lead related complications in quadripolar versus bipolar left ventricular leads.

BACKGROUND: Quadripolar left ventricular (LV) leads are capable of pacing from four different electrodes which allows for easier and more stable intra-operative lead positioning with optimal pacing parameters. We therefore investigated the rate of combined intra-operative and post-operative LV lead related events in quadripolar vs. bipolar LV lead cardiac resynchronization therapy (CRT) recipients in the real world setting. METHODS: We retrospectively collected data for N = 1441 patients at our institution implanted with quadripolar (n = 292) or bipolar (n = 1149) LV leads from 2012 to 2014 and followed them to the primary end-point of composite lead outcome defined as intra-operative lead implant failure or post-operative lead dislodgement or deactivations. RESULTS: Patients implanted with a quadripolar lead were younger (70.6 ± 11.4 vs 72.5 ± 11.6, p = 0.014) and had higher incidence of diabetes (41.8% vs 32.8%, p = 0.004) compared to those with bipolar leads. All other baseline characteristics were comparable. Patients implanted with a quadripolar were significantly less likely to reach the primary endpoint in the first 12 months after LV lead implantation (Hazard Ratio 0.22, 95% Confidence Interval 0.08-0.60, p = 0.001). There were no differences between the two groups in rates of hospitalization for any cause or in mortality. CONCLUSION: In this real world study, quadripolar LV leads have significantly lower rates of implantation failure and post-operative lead dislodgement or deactivation. These results have important clinical implications to CRT recipients.

Risk of Stroke and Death in Atrial Fibrillation by Type of Anticoagulation: A Propensity-Matched Analysis.

BACKGROUND: We examined the effect of novel oral anticoagulants (NOACs) compared to warfarin on the risk of death or stroke in atrial fibrillation (AF) patients in every day clinical practice. METHODS: We examined a cohort of 2,836 AF patients, of whom 2,253 were prescribed warfarin and 583 were prescribed an NOAC. Patients with glomerular filtration rate < 30 mg/mL or history of significant valvular heart disease were excluded. Patients were followed to primary end points of death or stroke. Propensity matching was used to adjust for differences in baseline characteristics between the groups. RESULTS: Compared to patients in the NOAC group, patients on warfarin had more comorbidities and higher CHADS2 and CHA2 DS2 -VASc scores (1.7 vs 1.3 for CHADS2 , 2.8 vs 2.2 for CHA2 DS2 -VASc, P < 0.0001 for both). After adjusting for differences in baseline characteristics, NOAC use was associated with significant reduction in all-cause mortality compared to warfarin (hazard ratio [HR] = 0.47, 95% confidence interval [CI; 0.3-0.8], P = 0.006) but not stroke, over a median follow-up of 42.5 months. The difference in mortality persisted after propensity score matching (HR = 0.51, 95% CI [0.28-0.93], P = 0.03). CONCLUSIONS: Compared to warfarin, NOAC use is associated with decreased all-cause mortality but not stroke risk. These data from real-life clinical practice add to existing evidence for decreased mortality among patients prescribed NOACs compared to warfarin.

Battery longevity in cardiac resynchronization therapy implantable cardioverter defibrillators.

AIMS: Cardiac resynchronization therapy (CRT) implantable cardioverter defibrillators (ICDs) deliver high burden ventricular pacing to heart failure patients, which has a significant effect on battery longevity. The aim of this study was to investigate whether battery longevity is comparable for CRT-ICDs from different manufacturers in a contemporary cohort of patients. METHODS AND RESULTS: All the CRT-ICDs implanted at our institution from 1 January 2008 to 31 December 2010 were included in this analysis. Baseline demographic and clinical data were collected on all patients using the electronic medical record. Detailed device information was collected on all patients from scanned device printouts obtained during routine follow-up. The primary endpoint was device replacement for battery reaching the elective replacement indicator (ERI). A total of 646 patients (age 69 ± 13 years), implanted with CRT-ICDs (Boston Scientific 173, Medtronic 416, and St Jude Medical 57) were included in this analysis. During 2.7 ± 1.5 years follow-up, 113 (17%) devices had reached ERI (Boston scientific 4%, Medtronic 25%, and St Jude Medical 7%, P < 0.001). The 4-year survival rate of device battery was significantly worse for Medtronic devices compared with devices from other manufacturers (94% for Boston scientific, 67% for Medtronic, and 92% for St Jude Medical, P < 0.001). The difference in battery longevity by manufacturer was independent of pacing burden, lead parameters, and burden of ICD therapy. CONCLUSION: There are significant discrepancies in CRT-ICD battery longevity by manufacturer. These data have important implications on clinical practice and patient outcomes.

Failure-free survival of the Durata defibrillator lead.

AIMS: Given design similarities and a common manufacturer, there have been suspicions regarding the Durata™ defibrillator (ICD) lead, in the aftermath of the Riata™ class I recall. We therefore examined the failure-free survival rates of the Durata™ compared with the Riata™ and Sprint Quattro™ ICD leads. METHODS AND RESULTS: All patients (n = 2475) implanted with a Durata (n = 828), Riata [n = 627; 8 Fr. (n = 472) and 7 Fr. (n = 155)], or Sprint Quattro (n = 1020) leads at our institution were included and Kaplan-Meier failure-free survival curves were constructed for all leads. Lead failure was defined as electrical malfunction resulting in lead replacement, excluding dislodgements or perforations. Annual electrical failure rates were 0.3%, 1.7, and 0.3% for the Durata, Riata, and Sprint Quattro leads, respectively (P < 0.0001 for the comparison of Durata to Riata and P = 0.1.0 for the comparison of Durata to Sprint Quattro). The failure-free survival of the Durata lead was significantly better than that of the Riata lead (P < 0.0001) and similar to that of the Sprint Quattro (P = 0.94). The 7 Fr. Riata ST lead had better survival compared with the 8 Fr. Riata lead (P = 0.050) and comparable survival with the Durata lead (P = 0.12). CONCLUSION: The Durata lead failure-free survival is significantly better than the 8 Fr. Riata, albeit at a shorter follow-up time. Riata and comparable with that of the 7 Fr. Riata ST and the Sprint Quattro ICD leads. These data provide an insight into the mechanism of electrical failure of Riata leads and have implications for patient management.

Antimicrobial Agents Based on Metal Complexes: Present Situation and Future Prospects.

The rise in antimicrobial resistance is a cause of serious concern since the ages. Therefore, a dire need to explore new antimicrobial entities that can combat against the increasing threat of antibiotic resistance is realized. Studies have shown that the activity of the strongest antibiotics has reduced drastically against many microbes such as microfungi and bacteria (Gram-positive and Gram-negative). A ray of hope, however, was witnessed in early 1940s with the development of new drug discovery and use of metal complexes as antibiotics. Many new metal-based drugs were developed from the metal complexes which are potentially active against a number of ailments such as cancer, malaria, and neurodegenerative diseases. Therefore, this review is an attempt to describe the present scenario and future development of metal complexes as antibiotics against wide array of microbes.

A Mini-Review on Lichen-Based Nanoparticles and Their Applications as Antimicrobial Agents.

Biological entities such as green plants, fungi, and lichens are now a days persistently explored for the synthesis of nanoparticles. Lichen-based nanoparticles are also becoming increasingly popular owing to their biocompatibility, eco-friendliness, and cost-effectiveness. The lichen-based metal nanomaterials, particularly synthesized using green chemistry approaches, have turned out to be great substitutes to conventional antimicrobial therapies. Many scientific reports established the significant antimicrobial properties exhibited by the lichen nanoparticles. Therefore, the present mini-review summarizes an overview of lichen-based nanomaterials, their synthesis, their applications, and the molecular mechanism of their potential as broad spectrum antimicrobial agents for biomedical applications.

Trends in Hospital Admissions for and Readmissions After Cardiac Implantable Electronic Device Procedures in the United States: An Analysis From 2010 to 2014 Using the National Readmission Database.

OBJECTIVE: To evaluate inpatient trends in de novo complete cardiac implantable electronic device (CIED) procedures and subsequent all-cause 30-day readmissions in the United States. PATIENTS AND METHODS: We accessed the National Readmission Database to identify CIED implantation-related hospitalizations between January 1, 2010, and December 31, 2014, using International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes. In-hospital mortality and postprocedure all-cause 30-day readmissions were also analyzed. RESULTS: During the study period, a total of 800,250 CIED implantation hospitalizations were identified across the United States, with an in-hospital mortality rate of 0.9% (7423 of 800,250) and a 29% decrease in CIED-related index hospitalizations (188,086 in 2010 vs 134,276 in 2014). The all-cause 30-day readmission rate for the entire cohort was 13% (106,505 of 800,250), decreasing from 14% (26,134 of 188,085) in 2010 to only 13% (17,154 of 134,276) by 2014. Dual-chamber pacemakers were the most frequently implanted in-hospital CIEDs (473,615 of 800,250 [59%]). The most common cause for readmission was heart failure exacerbation, which remained unchanged over the study period. CONCLUSION: Our data reveal a steady decline in overall in-hospital CIED implantations and only a modest decline in readmission rates. The cause for this decline may be an impact of medical and regulatory changes guiding CIED implantations, but it deserves further investigation.

Comparative effectiveness of antiarrhythmic drugs for rhythm control of atrial fibrillation.

INTRODUCTION: Although there are many different antiarrhythmic drugs (AADs) approved for rhythm management of atrial fibrillation (AF), little comparative effectiveness data exist to guide drug selection. METHODS: We followed 5952 consecutive AF patients who were prescribed amiodarone (N=2266), dronedarone (N=488), dofetilide (N=539), sotalol (N=1718), or class 1C agents (N=941) to the primary end point of AF recurrence. RESULTS: Median follow-up time was 18.2 months (range 0.1-101.6 months). Patients who were prescribed amiodarone had the highest, while patients on class 1C agents had the lowest baseline CHA2DS2-VASc score, Charlson comorbidity index, and burden of comorbid illnesses including coronary artery disease, congestive heart failure, diabetes mellitus, hyperlipidemia, chronic obstructive lung disease, chronic kidney disease, or cancer (p<0.05 for all comparisons). After adjusting for baseline characteristics, using dronedarone as benchmark, amiodarone [hazard ratio (HR) 0.58, p<0.001], class 1C agents (HR 0.70, p<0.001), and sotalol (HR 0.79, p=0.008), but not dofetilide (HR 0.87, p=0.178) were associated with less AF recurrence. In addition, compared to dronedarone, amiodarone and class 1C agents were associated with lower rates of admissions for AF (HR 0.55, p<0.001 for amiodarone; HR 0.71, p=0.021 for class 1C agents) and all-cause mortality was lowest in patients treated with class 1C agents (HR 0.42, p=0.018). The risk of stroke was similar among all groups. CONCLUSION: Compared with dronedarone, amiodarone, class 1C agents, and sotalol are more effective for rhythm control, while dofetilide had similar efficacy. These findings have important implications for clinical practice.

Patient outcomes according to adherence to treatment guidelines for rhythm control of atrial fibrillation.

BACKGROUND: Although guidelines for antiarrhythmic drug therapy in atrial fibrillation (AF) were published in 2006, it remains uncertain whether adherence to these guidelines affects patient outcomes. METHODS AND RESULTS: We retrospectively evaluated the records of 5976 consecutive AF patients who were prescribed at least 1 antiarrhythmic drug between 2006 and 2013. Patients with 1 or more prescribed antiarrhythmic drugs that did not comply with guideline recommendations comprised the non-guideline-directed group (=2920); the remainder constituted the guideline-directed group (=3056). Time to events was assessed using the survival analysis method and adjusted for covariates using Cox regression. Rates of adherence to the guidelines increased significantly with a higher degree of prescriber specialization in arrhythmias (49%, 55%, and 60% for primary care physicians, general cardiologists, and cardiac electrophysiologists, respectively, P=0.001) for the first prescribed antiarrhythmic drug. Compared to the non-guideline-directed group, the guideline-directed group had higher rates of heart failure, but lower baseline CHADS2-VASc scores (P<0.001) and lower rates of coronary artery disease, valvular disease, hypertension, hyperlipidemia, pulmonary disease, and renal insufficiency (P<0.05 for all). During 45 ± 26 months follow-up, the guideline-directed group had a lower risk of AF recurrence (hazard ratio=0.86, 95% CI=0.80 to 0.93), fewer hospital admissions for AF (hazard ratio=0.87, 95% CI=0.79 to 0.97), and fewer procedures for recurrent AF, including electrical cardioversion, pacemaker implantation, and atrioventricular nodal ablation (P<0.01 for all). The mortality and stroke risks were similar between the groups. CONCLUSIONS: Adherence to published guidelines in the antiarrhythmic management of AF is associated with improved patient outcomes.

Mortality risk of long-term amiodarone therapy for atrial fibrillation patients without structural heart disease.

BACKGROUND: Amiodarone is often prescribed in the management of atrial fibrillation (AF) but is known to cause significant end-organ toxicities. In this study, we examined the impact of amiodarone on all-cause mortality in AF patients with structurally normal hearts. METHODS: We performed a retrospective cohort analysis of all AF patients with structurally normal hearts who were prescribed antiarrhythmic drugs (AAD) for rhythm control of AF at our institution from 2006 to 2013 (n = 2,077). Baseline differences between the amiodarone (AMIO: n = 403) and other AADs (NON-AMIO: n = 1,674) groups were corrected for using propensity score matching. RESULTS: Amiodarone use as first-line therapy decreased significantly with a higher degree of prescriber specialization in arrhythmia management (31%, 22%, and 9% for primary care physicians, general cardiologists and cardiac electrophysiologists, respectively, p < 0.001). After propensity score matching, baseline comorbidities were balanced between the AMIO and NON-AMIO groups. Over a median follow-up of 28.2 months (range 6.0-100.9 months), amiodarone was associated with increased all-cause (HR 2.41, p = 0.012) and non-cardiac (HR 3.55, p = 0.008) mortality, but not cardiac mortality. AF recurrence and cardiac hospitalizations were similar between the two study groups. CONCLUSIONS: Amiodarone treatment of AF is associated with increased mortality in patients without structural heart disease and therefore should be avoided or only used as a second-line therapy, when other AF therapies fail. Adherence to guideline recommendations in the management of AF patients impacts clinical outcome.

Outcomes of Sprint Fidelis and Riata lead extraction: Data from 2 high-volume centers.

BACKGROUND: The Sprint Fidelis (SF) and the Riata (RT) implantable cardioverter-defibrillator leads have been recalled for premature failure. OBJECTIVE: Data on SF and RT extractions are limited; therefore, we performed a pooled analysis to compare the safety and efficacy of lead extraction for the SF and RT lead families. METHODS: We retrospectively reviewed consecutive patients undergoing transvenous extraction of SF and RT leads at Emory University and the University of Pittsburgh Medical Center from January 2007 to October 2013. Patients were placed into 2 groups based on the presence of an SF or RT lead. The primary endpoint was a major procedural complication, defined as death, need for urgent cardiac surgery, and hemopericardium or hemothorax that required an intervention. RESULTS: A total of 462 patients underwent extraction of recalled leads (SF, n = 360; RT, n = 102). The mean number of leads extracted in the RT group was higher than in the SF group (1.8 ± 0.9 vs 1.3 ± 0.7, P < .001), and there was a longer implantation time in the RT group (5.5 ± 2.5 vs 4.3 ± 2.0 years, P < .001). Complete procedural success was higher in the SF group (99.4% vs 96.1%, P =.024). Clinical success was similar (SF 99.4% vs RT 97.1%, P = .075). There were 6 major procedural complications in the entire cohort (1.3%). The rate of major complications was not different between the SF and RT groups (SF 1.1% vs RT 2.0%, P = .618). Total mortality was 0.65%, with no difference between the groups CONCLUSION: Our data from 2 high-volume centers suggest that extraction of SF and RT leads is associated with excellent clinical success and a similar rate of major procedural complications.

Longitudinal follow-up of implantable cardioverter defibrillator leads.

Although implantable cardioverter defibrillator (ICD) leads are prone to failure and Food and Drug Administration recall, comprehensive longitudinal studies investigating contemporary ICD lead survival rate in the United States are lacking. All patients receiving Medtronic, Boston Scientific, or St. Jude Medical transvenous ICD leads at the hospitals of the University of Pittsburgh Medical Center from 2000 to 2012 were included. Leads were classified as (1) functional lead, patient deceased; (2) functional lead, replaced; (3) failed lead, replaced; or (4) functional lead, active. Kaplan-Meier survival curves were constructed for all lead models separately and in aggregate. We followed 5,288 patients (1,020 Quattro, 623 Fidelis, 627 Riata, 828 Durata, and 2,190 Reliance) over 3.7 ± 3.3 years. Functional leads that were replaced included 30 Quattro (3%), 99 Fidelis (16%), 24 Riata (4%), 24 Durata (3%), and 62 Reliance (3%). Leads replaced because of failure included 11 Quattro (1%), 47 Fidelis (8%), 38 Riata (6%), 18 Durata (2%), and 26 Reliance (1%; p <0.001 for Food and Drug Administration recalled vs nonrecalled leads). Overall survival rate of all leads was 89.3% at 5 years. Survival curves of Riata and Fidelis diverged from nonrecalled leads at approximately 2 years. In conclusion, the overall survival rate of ICD leads is nearly 90% at 5 years. Survival curves of recalled leads diverge from nonrecalled leads after 2 years of implantation. These data have important implications on postmarket release monitoring of ICD leads and physicians' choice of leads.

Longitudinal follow-up of externalized Riata leads.

Riata family of implantable cardioverter defibrillator leads have demonstrated in situ conductor externalization, prompting a class I recall and the Food and Drug Administration recommendation for fluoroscopic screening. The natural history of externalized Riata leads, however, remains unclear. In this study, we examined the rate of electrical failure in Riata leads with externalized cables. We reviewed medical and implantable cardioverter defibrillator records of all 329 patients with Riata leads who underwent fluoroscopic screening from December 2011 to March 2012 at the University of Pittsburgh Medical Center hospitals. Externalization was present in 76 patients (23%); of whom, 24 (32%) had the Riata lead replaced shortly after screening. The remaining 52 patients were followed for 7.9 ± 2.9 months, during which 5 patients were lost to follow-up and 2 patients exhibited electrical lead failure resulting in lead replacement, an electrical failure rate of 6.4% per year in externalized leads. In conclusion, prospective follow-up data on externalized Riata leads suggest an electrical failure rate in excess of 6% per year. This high failure rate warrants consideration of prophylactic replacement of externalized Riata leads. Further studies examining the natural history of Riata leads are warranted.

Class I recall of defibrillator leads: a comparison of the Sprint Fidelis and Riata families.

BACKGROUND: In recent years, 2 popular implantable cardioverter-defibrillator (ICD) leads have undergone a class I recall by the Food and Drug Administration (FDA): the Sprint Fidelis and the Riata leads. OBJECTIVE: To examine the failure rates of these 2 leads with respect to their date of FDA recall. METHODS: All patients implanted with a Sprint Fidelis, Riata, or Sprint Quattro lead at our institution were included. Kaplan-Meier failure-free survival curves were constructed with and without censoring at the dates of announcement of the FDA recall for each lead. RESULTS: A total of 2270 patients (623 Sprint Fidelis, 627 Riata, and 1020 Sprint Quattro) were included. The failure-free survival of the Sprint Quattro lead was significantly better than that of the Riata lead (P <.0001), which in turn was better than that of the Sprint Fidelis lead (P = .0214). After censoring events at the time of the FDA recall for each lead, the failure-free survival of the Sprint Quattro lead continued to be superior to that of the Riata (P <.0001) and Sprint Fidelis (P = .0124) leads but the difference between the Riata and Sprint Fidelis leads was eliminated (P = .123). CONCLUSIONS: In this study, a comparative analysis of the failure-free survival of 2 recalled leads demonstrates discrepancies in the timing of the recall despite comparable failure-free survival patterns leading to the recall. The causes of these discrepancies are unclear and raise questions regarding the consistency of postmarketing surveillance and manufacturers' reporting of malfunctions of medical devices.

Fluoroscopic screening of asymptomatic patients implanted with the recalled Riata lead family.

BACKGROUND: The Food and Drug Administration recently issued a class I recall of the St. Jude Medical Riata implantable cardioverter-defibrillator lead presumably because of increased risk of electric failure and mechanical separation via inside-out abrasion. We sought to examine the incidence and time dependence of inside-out abrasion in asymptomatic patients implanted with the Riata lead. METHODS AND RESULTS: Asymptomatic patients implanted with the Riata lead at our institution were offered voluntary fluoroscopic screening in 3 views. Electric testing of the Riata lead with provocative isometric muscle contraction was performed at the time of fluoroscopic screening. Of the 245 patients undergoing fluoroscopic screening, 53 (21.6%) patients showed clear evidence of lead separation. Of these externalized leads, 0%, 13%, and 26% had a dwell time of <3 years, 3 to 5 years, and >5 years, respectively (P=0.037). Externalized leads had a significantly pronounced decrease in R-wave amplitude (-1.7±2.9 mV versus +0.35±2.5 mV; P<0.001), and more patients with externalized leads had ≥25% decrease in R-wave amplitude from baseline (28.0% versus 8.1%; P=0.018). One patient with externalization exhibited new noise on near-field electrogram. CONCLUSIONS: The Riata lead exhibits time-dependent high rates of cable externalization exceeding 20% at >5 years of dwell time. Externalized leads are associated with a more pronounced decrease in R-wave amplitude, which may be an early marker of future electric failure. The use of fluoroscopic and electric screening of asymptomatic patients with the Riata lead remains controversial in the management of patients affected by the recent Food and Drug Administration recall.