Amit Kaura

Outcomes with single-coil versus dual-coil implantable cardioverter defibrillators: a meta-analysis

Aims Dual-coil implantable cardioverter defibrillator (ICD) leads have traditionally been used over single-coil leads due to concerns regarding high defibrillation thresholds (DFT) and consequent poor shock efficacy. However, accumulating evidence suggests that this position may be unfounded and that dual-coil leads may also be associated with higher complication rates during lead extraction. This meta-analysis collates data comparing dual- and single-coil ICD leads. Methods and results Electronic databases were systematically searched for randomized controlled trials (RCT) and non-randomized studies comparing single-coil and dual-coil leads. The mean differences in DFT and summary estimates of the odds-ratio (OR) for first-shock efficacy and the hazard-ratio (HR) for all-cause mortality were calculated using random effects models. Eighteen studies including a total of 138,124 patients were identified. Dual-coil leads were associated with a lower DFT compared to single coil leads (mean difference -0.83J; 95% confidence interval [CI] -1.39--0.27; P = 0.004). There was no difference in the first-shock success rate with dual-coil compared to single-coil leads (OR 0.74; 95%CI 0.45-1.21; P=0.22). There was a significantly lower risk of all-cause mortality associated with single-coil leads (HR 0.91; 95%CI 0.86-0.95; P < 0.0001). Conclusion This meta-analysis suggests that single-coil leads have a marginally higher DFT but that this may be clinically insignificant as there appears to be no difference in first-shock efficacy when compared to dual-coil leads. The mortality benefit with single-coil leads most likely represents patient selection bias. Given the increased risk and complexity of extracting dual-coil leads, centres should strongly consider single-coil ICD leads as the lead of choice for routine new left-sided ICD implants.

The Significance of Shocks in Implantable Cardioverter Defibrillator Recipients.

Large-scale implantable cardioverter defibrillator (ICD) trials have unequivocally shown a reduction in mortality in appropriately selected patients with heart failure and depressed left ventricular function. However, there is a strong association between shocks and increased mortality in ICD recipients. It is unclear if shocks are merely a marker of a more severe cardiovascular disease or directly contribute to the increase in mortality. The aim of this review is to examine the relationship between ICD shocks and mortality, and explore possible mechanisms. Data examining the effect of shocks in the absence of spontaneous arrhythmias as well as studies of non-shock therapy and strategies to reduce shocks are analysed to try and disentangle the shocks versus substrate debate.

Inception of the ‘endocarditis team’ is associated with improved survival in patients with infective endocarditis who are managed medically: findings from a before-and-after study

Objective Despite improvements in its management, infective endocarditis (IE) is associated with poor survival. The aim of this study was to evaluate the impact of a multidisciplinary endocarditis team (ET), including a cardiologist, microbiologist and a cardiac surgeon, on the outcome of patients with acute IE according to medical or surgical treatment strategies. Methods We conducted an observational before-and-after study of 196 consecutive patients with definite IE, who were treated at a tertiary reference centre between 2009 and 2015. The study was divided into two periods: period 1, before the formation of the ET (n=101), and period 2, after the formation of the ET (n=95). The role of the ET included regular multidisciplinary team meetings to confirm diagnosis, inform the type and duration of antibiotic therapy and recommend early surgery, when indicated, according to European guidelines. Results The patient demographics and predisposing conditions for IE were comparable between the two study periods. In the time period following the introduction of the ET, there was a reduction in both the time to commencement of IE-specific antibiotic therapy (4.0±4.0 days vs 2.5±3.2 days; P=0.004) and the time from suspected IE to surgery (7.8±7.3 days vs 5.3±4.2 days; P=0.004). A 12-month Kaplan-Meier survival for patients managed medically was 42.9% in the pre-ET period and 66.7% in the post-ET period (P=0.03). The involvement of the ET was a significant independent predictor of 1-year survival in patients managed medically (HR 0.24, 95% CI 0.07 to 0.87; P=0.03). Conclusions A standardised multidisciplinary team approach may lead to earlier diagnosis of IE, more appropriate individualised management strategies, expedited surgery, where indicated, and improved survival in those patients chosen for medical management, supporting the recent change in guidelines to recommend the use of a multidisciplinary team in the care of patients with IE.

51 Outcomes with single-coil versus dual-coil implantable cardioverter-defibrillators: a meta-analysis

Aims Dual-coil implantable cardioverter defibrillator (ICD) leads have traditionally been used over single-coil leads due to concerns regarding high defibrillation thresholds (DFT) and consequent poor shock efficacy. However, accumulating evidence suggests that this position may be unfounded and that dual-coil leads may also be associated with higher complication rates during lead extraction. This meta-analysis collates data comparing dual- and single-coil ICD leads. Methods and results Electronic databases were systematically searched for randomised controlled trials (RCT) and non-randomised studies comparing single-coil and dual-coil leads. The mean differences in DFT and summary estimates of the odds-ratio (OR) for first-shock efficacy and the hazard-ratio (HR) for all-cause mortality were calculated using random effects models. Eighteen studies including a total of 1 38 124 patients were identified. Dual-coil leads were associated with a lower DFT compared to single coil leads (mean difference –0.83J; 95% confidence interval [CI] –1.39–−0.27; p=0.004). There was no difference in the first-shock success rate with dual-coil compared to single-coil leads (OR 0.74; 95% CI 0.45–1.21; p=0.22). There was a significantly lower risk of all-cause mortality associated with single-coil leads (HR 0.91; 95% CI 0.86–0.95; p<0.0001). Conclusion This meta-analysis suggests that single-coil leads have a marginally higher DFT but that this may be clinically insignificant as there appears to be no difference in first-shock efficacy when compared to dual-coil leads. The mortality benefit with single-coil leads most likely represents patient selection bias. Given the increased risk and complexity of extracting dual-coil leads, centres should strongly consider single-coil ICD leads as the lead of choice for routine new left-sided ICD implants.

46 The Impact of Pulmonary Artery Systolic Pressure on New York Heart Association Functional Status After Transcatheter Aortic Valve Implantation

Introduction Transcatheter aortic valve implantation (TAVI) is a therapeutic option for high surgical risk patients with symptomatic aortic stenosis. While improvements in pulmonary artery systolic pressure (PASP) following TAVI have been reported, data regarding the effect of changes in PASP on patient functional status are limited. Methods We performed a retrospective analysis of all consecutive TAVI procedures recorded on the UK TAVI registry from our institution between January 2007 and January 2015. Functional status was defined by the New York Heart Association (NYHA) classification and PASP assessed by transthoracic echocardiography. Repeat measures of PASP and NYHA were performed prior to TAVI and at 1-, 6- and 12-– months following TAVI. Linear mixed model for repeated measures analysis was used to detect changes in PASP and NYHA over the three time points following TAVI and to measure their association. Adjusting for traditional risk factors, we subsequently evaluated whether PASP and NYHA predicted 1-year mortality following TAVI. Results Over eight years, 299 patients (48% male, age 84 ± 8 years) underwent TAVI. During a mean follow-up of 775 days, 114 patients died. One month following TAVI, there was a significant reduction in PASP (37.3 ± 1.7 to 32.4 ± 1.7 mm Hg, p < 0.0001), which remained at 6-months (33.7 ± 1.9 mm Hg, p = 0.03), yet at 12-months the pressure had returned to baseline levels (35 ± 2.2 mm Hg). There was a significant decrease in NYHA at 1-month following TAVI (2.3 ± 0.1 to 1.5 ± 0.1, p < 0.0001). The improvement in NYHA persisted both at 6-months (1.5 ± 0.1, p < 0.0001) and at 12-months (1.6 ± 0.1, p < 0.0001) following TAVI. In linear mixed model analysis, after adjusting for left ventricular ejection fraction (LVEF), we observed an association between changes in PASP and NYHA following TAVI (coefficient 0.030 ± 0.01, p < 0.0001). An improvement in NYHA by one functional class was therefore associated with a reduction in PASP by 42 mm Hg. In univariate Cox regression analyses, PASP, NYHA and LVEF, at 1-month following TAVI, all predicted 1-year mortality (p < 0.05). In multivariate analysis, only NYHA at 1-month following TAVI was independently related to 1-year mortality (hazard ratio 1.80, 95% confidence interval 1.21 to 2.69, p = 0.004). Conclusion These data provide evidence that the reduction in PASP observed following TAVI is closely correlated with an improvement in NYHA functional class along with mortality at 1-year. This study will help enable cardiovascular clinicians to identify those patients likely to have a favourable symptomatic response to TAVI based on the echocardiographic PASP estimate post-procedure.

71 Identifying Patients with Less Potential to Benefit from Implantable Cardiac Defibrillator Therapy

Background Implantable cardiac defibrillator (ICD) therapy reduces mortality in selected patients at high risk of sudden cardiac death. However, patients at high risk of non-sudden cardiac death, whose risk of short-term mortality following device implantation is high, may gain no significant benefit from an ICD. A number of approaches have been proposed to identify these high-risk patients, including single clinical markers and more complex scoring systems. The aims of this study were to use the proposed scoring systems to: (1) establish how many current ICD recipients may be too high risk to derive significant benefit from ICD therapy and (2) evaluate how well the proposed scoring systems predict short-term mortality in an unselected cohort of ICD recipients. Methods We performed asingle-centre retrospective observational study of all new ICD implants over 5years (2009–2013). We used 3 published scoring systems (Kramer et al 1; Barsheshet et al 2; Parkash et al 3) to identify new ICDrecipients whose short-term risk of death following ICD implantation waspredicted to be high. We then evaluated how well the scoring systems predicteddeath during follow-up. Results Over 5 years there were 406 new implants (79% male, age 67 ± 13 years). The majority (58%) were primary prevention implants and 45% were cardiac resynchronisation therapy-defibrillator devices. During a mean follow-up of 936 ± 560 days, 77 patients died. Using the published scoring systems, the proportion of ICD recipients predicted to be at high risk of short-term mortality were 4% (Kramer), 36% (Barsheshet) and 23% (Parkash). Three-year mortality rates in these high-risk groups were 76%, 32% and 36% respectively; in the overall study population 3-year mortality was 20%. In univariate Cox regression analyses, all 3 scoring systems predicted death (p < 0.001 for each model). However, using multivariate analysis, only the Kramer model remained predictive once serum urea was included in the analysis (p < 0.001). The ROC scores for the prediction of death for the 3 scoring systems and urea were 0.73 (Kramer), 0.69 (Barsheshet), 0.65 (Parkash) and 0.70 (urea). Conclusions Using published scoring systems, a significant proportion of current ICD recipients are at high risk of short-term mortality following device implantation. Although all 3 scoring systems predicted mortality during follow-up, only the Kramer model added predictive accuracy compared to renal function alone. RENCES Kramer DB, Friedman PA, Kallinen LM, Morrison TB, Crusan DJ, Hodge DO, Reynolds MR, Hauser RG. Development and validation of a risk score to predict early mortality in recipients of implantable cardioverter-defibrillators. Heart Rhythm 2012;9:42–6 Barsheshet A, Moss AJ, Huang DT, McNitt S, Zareba W, Goldenberg I. Applicability of a risk score for prediction of the long-term (8-year) benefit of the implantable cardioverter-defibrillator. J Am Coll Cardiol 2012;59:2075–9 Parkash R, Stevenson WG, Epstein LM, Maisel WH. Predicting early mortality after implantable defibrillator implantation: a clinical risk score for optimal patient selection. Am Heart J 2006;151:397–403