Die dilatative Kardiomyopathie als genetische Erkrankung

Outcome predictors in dilated cardiomyopathy or myocarditis

BACKGROUND

The objective of this study was to identify parameters of prognostic relevance in patients presenting with chronic left ventricular dysfunction who underwent endomyocardial biopsy.

MATERIALS AND METHODS

A total of 351 consecutive patients (age 47·7 ± 12·6 years, 281 male) with a chronic left ventricular dysfunction were enrolled. Endomyocardial biopsies were analysed by histopathology according to Dallas criteria and immunohistological WHO criteria. Virus genome was detected by polymerase chain reaction. The combined end point was time to death or heart transplantation.

RESULTS

About 19% of patients (n = 67) showed positive Dallas criteria and 39% (n = 118) immunohistochemical signs of inflammation. Viral genome was present in 58% (n = 155). During follow-up, 25% (n = 89; 76 death, 13 HTx) reached the end point. Dallas-positive histopathology (hazard ratio: 0·42; 95% CI: 0·29-0·84, P = 0·031), ejection fraction (hazard ratio: 0·97; 95% CI: 0·94-0·99, P = 0·019) and β-blocker therapy (hazard ratio: 0·41; 95% CI: 0·23-0·69, P = 0·003) were independent outcome predictors. For patients under β-blocker therapy, Dallas-positive histopathology (hazard ratio: 0·37; 95% CI: 0·25-0·76, P = 0·009) and NYHA class III and class IV (hazard ratio: 2·11; 95% CI: 1·04-3·12, P = 0·006) were independent predictors.

CONCLUSIONS

For patients with a chronic left ventricular dysfunction, Dallas-positive histopathology, β-blocker therapy and left ventricular ejection fraction are the most striking parameters for outcome prediction.

Etiology-specific assessment of predictors of long-term survival in chronic systolic heart failure

BACKGROUND

We sought to identify prognostic factors of long-term mortality, specific for the underlying etiology of chronic systolic heart failure (CHF).

METHODS AND RESULTS

Between 1995 and 2009 baseline characteristics, treatment and follow-up data from 2318 CHF-patients due to ischemic (ICM; 1100 patients) or dilated cardiomyopathy (DCM; 1218 patients) were prospectively compared. To calculate hazard ratios with 95%-confidence intervals cox regression was used. We respectively established etiology-specific multivariable models of independent prognostic factors. During the follow-up period of up to 14.8 years (mean = 53.1 ± 43.5 months; 10,264 patient-years) 991 deaths (42.8%) occurred. In the ICM-cohort, 5-year-survival was 53.4% (95% CI: 49.9-56.7%), whereas in DCM-patients it was higher (68.1% (95% CI: 65.1-71.0%)). Age, ejection fraction, or hyponatremia were independent predictors for mortality in both cohorts, whereas diabetes, COPD, atrial fibrillation and a heart rate of ≥ 80/min carried independent predictive power only in ICM-patients.

CONCLUSION

This study demonstrates the disparity of prognostic value of clinically derived risk factors between the two main causes of CHF. The effects of covariables in DCM-patients were lower, suggesting a less modifiable disease through risk factors considering mortality risk. An etiology-specific prognostic model may improve accuracy of survival estimations in CHF.

Targeted next-generation sequencing for the molecular genetic diagnostics of cardiomyopathies

BACKGROUND

Today, mutations in more than 30 different genes have been found to cause inherited cardiomyopathies, some associated with very poor prognosis. However, because of the genetic heterogeneity and limitations in throughput and scalability of current diagnostic tools up until now, it is hardly possible to genetically characterize patients with cardiomyopathy in a fast, comprehensive, and cost-efficient manner.

METHODS AND RESULTS

We established an array-based subgenomic enrichment followed by next-generation sequencing to detect mutations in patients with hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). With this approach, we show that the genomic region of interest can be enriched by a mean factor of 2169 compared with the coverage of the whole genome, resulting in high sequence coverage of selected disease genes and allowing us to define the genetic pathogenesis of cardiomyopathies in a single sequencing run. In 6 patients, we detected disease-causing mutations, 2 microdeletions, and 4 point mutations. Furthermore, we identified several novel nonsynonymous variants, which are predicted to be harmful, and hence, might be potential disease mutations or modifiers for DCM or HCM.

CONCLUSIONS

The approach presented here allows for the first time a comprehensive genetic screening in patients with hereditary DCM or HCM in a fast and cost-efficient manner.