ICD Complications in RCTs vs Registries
ICD Complications in RCTs vs Registries
PubMed was searched on 31 July 2013 for English language RCTs in humans, with abstracts available, using the following criteria: (implantable cardioverter defibrillator OR ICD) AND (complications OR adverse event) NOT ICD-9 NOT ICD-10. This identified 187 articles which were screened and of these, 17 met the criteria for inclusion, which were any RCT reporting explicit data on transvenous, non-thoracotomy ICD complications (except inappropriate ICD intervention) regardless of whether or not the study was primarily of ICDs. In the case of serial publications, only the most recent or most appropriate study was included in the analysis. Exclusion criteria were studies specifically of hypertrophic cardiomyopathy (HCM), children, congenital heart disease, resynchronisation therapy and generator changes. Complications of ICD implantation occurring in patients with HCM have recently been comprehensively presented in a review by Schinkel et al The IRIS study (which was not returned in the original search due to use of the MESH term 'adverse effects' rather than 'adverse events') was also subsequently included in the analysis, thus bringing the total number of RCTs to 18.
Selected RCTs were reviewed and relevant patient characteristics, potential risk factors for complications and follow-up duration were recorded. No time restriction for complications was used. Even after exclusion of studies without explicit complication data, the studies varied greatly in the manner and depth in which complications were reported and not all described a detailed breakdown. The outcome data available therefore varied according to the criteria used in each particular RCT. An inclusive list of the different complication categories used by the studies is as follows: total complications, 30-day mortality, pneumothorax, haemothorax, haematoma, bleeding, dissection, perforation, tamponade, need for transfusion, thrombosis, displacement, displacement requiring repositioning, other displacement, lead failure or dislodgement, need for lead revision/replacement, need for additional lead, lead fracture, insulation failure, lead under sensing, T wave over sense, generator failure, generator migration/erosion, generator revision, infection, erosion and Twiddler's syndrome.
Statistical analysis was performed using Microsoft Excel 2010 (Microsoft Corporation, Redmond, Washington, USA) and COMPREHENSIVE META-ANALYSIS software V.2, Biostat, Englewood, USA. Complication event rates were pooled together using inverse variance weighting. Heterogeneity among the studies was evaluated using the Iindex. Publication bias was assessed by Begg's adjusted rank correlation test and Egger's regression asymmetry test. Continuous variables were reported as mean. Categorical variables were summarised as percentages. From the pooled data, a fixed effects model was used to calculate summary estimates of patient characteristics and potential risk factors for complications. Meta regression analysis was used to investigate if any variable was associated with specific study outcomes. Poisson regression was used to comparing data from RCTs to that from the registry.
Methods
Literature Review, Inclusion and Exclusion Criteria
PubMed was searched on 31 July 2013 for English language RCTs in humans, with abstracts available, using the following criteria: (implantable cardioverter defibrillator OR ICD) AND (complications OR adverse event) NOT ICD-9 NOT ICD-10. This identified 187 articles which were screened and of these, 17 met the criteria for inclusion, which were any RCT reporting explicit data on transvenous, non-thoracotomy ICD complications (except inappropriate ICD intervention) regardless of whether or not the study was primarily of ICDs. In the case of serial publications, only the most recent or most appropriate study was included in the analysis. Exclusion criteria were studies specifically of hypertrophic cardiomyopathy (HCM), children, congenital heart disease, resynchronisation therapy and generator changes. Complications of ICD implantation occurring in patients with HCM have recently been comprehensively presented in a review by Schinkel et al The IRIS study (which was not returned in the original search due to use of the MESH term 'adverse effects' rather than 'adverse events') was also subsequently included in the analysis, thus bringing the total number of RCTs to 18.
Data Extraction
Selected RCTs were reviewed and relevant patient characteristics, potential risk factors for complications and follow-up duration were recorded. No time restriction for complications was used. Even after exclusion of studies without explicit complication data, the studies varied greatly in the manner and depth in which complications were reported and not all described a detailed breakdown. The outcome data available therefore varied according to the criteria used in each particular RCT. An inclusive list of the different complication categories used by the studies is as follows: total complications, 30-day mortality, pneumothorax, haemothorax, haematoma, bleeding, dissection, perforation, tamponade, need for transfusion, thrombosis, displacement, displacement requiring repositioning, other displacement, lead failure or dislodgement, need for lead revision/replacement, need for additional lead, lead fracture, insulation failure, lead under sensing, T wave over sense, generator failure, generator migration/erosion, generator revision, infection, erosion and Twiddler's syndrome.
Statistical Analysis
Statistical analysis was performed using Microsoft Excel 2010 (Microsoft Corporation, Redmond, Washington, USA) and COMPREHENSIVE META-ANALYSIS software V.2, Biostat, Englewood, USA. Complication event rates were pooled together using inverse variance weighting. Heterogeneity among the studies was evaluated using the Iindex. Publication bias was assessed by Begg's adjusted rank correlation test and Egger's regression asymmetry test. Continuous variables were reported as mean. Categorical variables were summarised as percentages. From the pooled data, a fixed effects model was used to calculate summary estimates of patient characteristics and potential risk factors for complications. Meta regression analysis was used to investigate if any variable was associated with specific study outcomes. Poisson regression was used to comparing data from RCTs to that from the registry.
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