Development and validation of a clinical index to predict survival after cardiac resynchronisation therapy
OPEN ACCESS- F Leyva1,
- P W X Foley1,
- B Stegemann2,
- J A Ward3,
- L L Ng4,
- M P Frenneaux5,
- F Regoli6,
- R E A Smith1,
- A Auricchio6
- 1University of Birmingham, Department of Cardiology, Good Hope Hospital, Heart of England NHS Trust, Sutton Coldfield, UK
- 2Medtronic Inc, Bakken Research Center, Maastricht, The Netherlands
- 3University of Birmingham, Birmingham, UK
- 4University of Leicester, Leicester, UK
- 5Queen Elizabeth Hospital, University of Birmingham, Birmingham, UK
- 6Fondazione Cardiocentro Ticino, Lugano, Switzerland
- Correspondence to Dr Francisco Leyva, Department of Cardiology, University of Birmingham, Good Hope Hospital, Rectory Road, Sutton Coldfield, West Midlands B75 7RR, UK; cardiologists{at}hotmail.com
- Accepted 23 June 2009
- Published Online First 9 July 2009
Abstract
Objective: To develop and validate a prognostic risk index of cardiovascular mortality after cardiac resynchronisation therapy (CRT).
Design: Prospective cohort study.
Setting: District general hospital.
Patients: 148 patients with heart failure (mean age 66.7 (SD 10.4) years), New York Heart Association class III or IV, LVEF <35%) who underwent CRT.
Interventions: CRT device implantation.
Main outcome measures: Value of a composite index in predicting cardiovascular mortality, validated internally by bootstrapping. The predictive value of the index was compared to factors that are known to predict mortality in patients with heart failure.
Results: All patients underwent assessment of 16 prognostic risk factors, including cardiovascular magnetic resonance (CMR) measures of myocardial scarring (gadolinium-hyperenhancement) and dyssynchrony, before implantation. Clinical events were assessed after a median follow-up of 913 (interquartile range 967) days. At follow-up, 37/148 (25%) of patients died from cardiovascular causes. In Cox proportional hazards analyses, (DSC) Dyssynchrony, posterolateral Scar location (both p<0.0001) and Creatinine (p = 0.0046) emerged as independent predictors of cardiovascular mortality. The DSC index, derived from these variables combined, emerged as a powerful predictor of cardiovascular mortality. Compared to patients with a DSC <3, cardiovascular mortality in patients in the intermediate DSC index (3–5; HR: 11.1 (95% confidence interval (CI) 3.00 to 41.1), p = 0.0003) and high DSC index (≥5; HR: 30.5 (95% CI 9.15 to 101.8), p<0.0001) were higher. Bootstrap validation confirmed excellent calibration and internal validity of the prediction model.
Conclusion: The DSC index, derived from a standard CMR scan and plasma creatinine before implantation, is a powerful predictor of cardiovascular mortality after CRT.
Footnotes
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Funding The role of the industry sponsors was, exclusively, to fund research fellowships. BS, who was employed by Medtronic Inc, at the time of writing, provided statistical expertise and was involved in the review of the manuscript. The other authors had full independence from the sponsors with regard to study design, data collection, interpretation and manuscript preparation.
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Competing interests SC and PF have research fellowships sponsored by Medtronic Inc. BS was an employee of Medtronic Inc. REAS, PJ and FL have received sponsorship from Medtronic Inc. FL and KK have also received sponsorship from St Jude Medical. MPF is a consultant for Medtronic Inc. AA has research fellowships sponsored by Medtronic Inc, Boston Scientific Corp and St Jude Medical, and is consultant for Medtronic Inc, and Sorin. He has also received speaker fees from Medtronic Inc, Sorin and Biotronik.
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Provenance and peer review Not commissioned; externally peer reviewed.
