Assessment of Myocardial Scarring Improves Risk Stratification in Patients Evaluated for Cardiac Defibrillator Implantation
ABSTRACT We tested whether an assessment of myocardial scarring by cardiac magnetic resonance imaging (MRI) would improve risk stratification in patients evaluated for implantable cardioverter-defibrillator (ICD) implantation.
Current sudden cardiac death risk stratification emphasizes left ventricular ejection fraction (LVEF); however, most patients suffering sudden cardiac death have a preserved LVEF, and many with poor LVEF do not benefit from ICD prophylaxis.
One hundred thirty-seven patients undergoing evaluation for possible ICD placement were prospectively enrolled and underwent cardiac MRI assessment of LVEF and scar. The pre-specified primary endpoint was death or appropriate ICD discharge for sustained ventricular tachyarrhythmia.
During a median follow-up of 24 months the primary endpoint occurred in 39 patients. Whereas the rate of adverse events steadily increased with decreasing LVEF, a sharp step-up was observed for scar size >5% of left ventricular mass (hazard ratio [HR]: 5.2; 95% confidence interval [CI]: 2.0 to 13.3). On multivariable Cox proportional hazards analysis, including LVEF and electrophysiological-study results, scar size (as a continuous variable or dichotomized at 5%) was an independent predictor of adverse outcome. Among patients with LVEF >30%, those with significant scarring (>5%) had higher risk than those with minimal or no (≤5%) scarring (HR: 6.3; 95% CI: 1.4 to 28.0). Those with LVEF >30% and significant scarring had risk similar to patients with LVEF ≤30% (p = 0.56). Among patients with LVEF ≤30%, those with significant scarring again had higher risk than those with minimal or no scarring (HR: 3.9; 95% CI: 1.2 to 13.1). Those with LVEF ≤30% and minimal scarring had risk similar to patients with LVEF >30% (p = 0.71).
Myocardial scarring detected by cardiac MRI is an independent predictor of adverse outcome in patients being considered for ICD placement. In patients with LVEF >30%, significant scarring (>5% LV) identifies a high-risk cohort similar in risk to those with LVEF ≤30%. Conversely, in patients with LVEF ≤30%, minimal or no scarring identifies a low-risk cohort similar to those with LVEF >30%.
Full-textDOI: · Available from: Michele Parker, Dec 29, 2014
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ABSTRACT: Cardiovascular magnetic resonance using late gadolinium enhancement (LGE) provides a unique opportunity to assess myocardial tissue in vivo. LGE enables tissue characterization in ischemic and nonischemic cardiomyopathies and other cardiac diseases. LGE is associated with adverse clinical outcomes across a range of different cardiac conditions and may improve risk stratification for death, sudden cardiac death, or serious adverse events beyond traditional prognostic markers. Generally, matching data for the prognostic impact of LGE are frequently reached in cardiac disorders. In other diseases, only a limited number of trials are available, but it is anticipated that the prognostic impact of delayed enhancement will become evident. The development and validation of new cardiovascular magnetic resonance methods for diffuse myocardial fibrosis measurements would even improve the prognostic impact of LGE. The evaluation of diffuse myocardial fibrosis has a great potential in large-scale diseases, including their initial phases, with the possibility to identify patients at risk for subsequent development of clinical heart failure, to assess repeatedly the stage and progression of cardiac diseases, and to monitor the effect of treatment.Cardiology in review 01/2014; 22(3):128-39. DOI:10.1097/CRD.0000000000000002 · 3.24 Impact Factor
- Journal of the American College of Cardiology 07/2012; 60(5):421-2. DOI:10.1016/j.jacc.2012.02.071 · 15.34 Impact Factor
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ABSTRACT: Late Gadolinium Enhancement and Arrhythmias. Introduction : The extent of left ventricular (LV) scar, characterized by late gadolinium enhancement cardiac MRI (LGE-CMR), has been shown to predict the occurrence of ventricular arrhythmias in implantable cardioverter defibrillator (ICD) recipients. However, the specificity of LGE-CMR for sudden cardiac death (SCD) versus non-SCD is unclear. The aim of this retrospective, observational study was to evaluate this relationship in a cohort of ICD recipients. Methods and Results : We included consecutive patients who had undergone LGE-CMR before ICD implantation over a 4-year period (2006-2009). Scar (defined as myocardium with a signal intensity ≥50% of the maximum in scar tissue) was characterized in terms of percent scar and number of transmural LV scar segments in a 17-segment model. The endpoints were appropriate ICD therapy and all-cause mortality. Sixty-four patients (average age 66 ± 11 years, 51 male, median LVEF 30%) were included. During 42 ± 13 months follow-up, appropriate ICD therapy occurred in 28 patients (44%), and 14 patients (22%) died. Number of transmural scar segments (P = 0.005) and percentage LV scar (P = 0.03) were both significantly associated with appropriate ICD therapy. However, neither number of transmural scar segments (P = 0.32) or percent LV scar (P = 0.59) was significantly associated with all-cause mortality. Conclusion : In this observational study, in medium-term follow-up, the extent of LV scar characterized by LGE-CMR was strongly associated with the occurrence of spontaneous ventricular arrhythmias but not all-cause mortality. We hypothesize that scar quantification by LGE-CMR may be more specific for SCD than non-SCD, and may prove a valuable tool for the selection of patients for ICD therapy. (J Cardiovasc Electrophysiol, Vol. pp. 1-7).Journal of Cardiovascular Electrophysiology 10/2012; 24(4). DOI:10.1111/jce.12035 · 2.88 Impact Factor
Questions & Answers about this publication
- When are we going to use cardiac delayed enhancement in the risk stratification of ICD implantation candidates? LVEF is almost the only parameter used to decide upon ICD implantation in patients for primary prevention, all this based upon MADIT and MADIT-affiliated trials. This strategy has led us to over-implant ICD devices in patients with significant consequences on health economics and patient morbidity.
Delayed enhancement, one of the most robust parameters brought to the table by MRI, has now heavy evidence backing up its predictive value on cardiac mortality and ventricular arrhythmias in various types of cardiomyopathies.
We need to re-do the MADIT trials implementing delayed enhancement in the therapeutic management decision.Following