Precision medicine: myocardial fibrosis burden and genotype predict outcome in non-ischemic dilated cardiomyopathy (DCM)

Introduction

Myocardial fibrosis occurs during pathological remodeling of the heart and can be associated with worse outcome in affected patients. Genetic background is also known to affect patients' survival. In this study we sought to estimate patients' overall fibrosis burden by combining independent modalities including left ventricular endomyocardial biopsy (LV-EMB), circulating biomarkers, and cMRI. We also aimed to use patients' genetics information to predict outcome. Furthermore, we investigated the correlation between cardiac fibrosis and genetic variations to detect novel susceptibility loci for fibrosis in DCM.

Methods

A total number of 542 DCM patients were included. Collagen volume fraction (CVF) was automatically estimated from biopsies. 13 circulating fibrosis biomarkers were measured using Human Magnetic Luminex Screening Assays, and the cMRIs were screened for presence of LGE. Whole exome sequencing (WES) was performed in 410 patients of the cohort using illumina HiSeq 2000. Common (MAF ≥0.05 in the study population OR gnomAD NFE AF ≥0.01) and non-common missense variants (MAF <0.05 in the study population AND gnomAD NFE AF <0.01) in 42 DCM genes were tested for associations with end points using single variants and burden analyses respectively. Analyses were adjusted for age and sex and performed using R and SKAT. End points were all-cause mortality and a composite of heart failure (HF) associated events.

Results

The median follow-up time was 43.2 months (2084 patient-years). Sixty-two patients reached the composite end point and 55 died. LV-EMB proved to be a safe procedure with a total complication rate of 2.3%. Machine learning based characterization of biopsies was highly accurate. Although the 3 different modalities did not significantly correlate with one another, the extent of CVF, levels of MMP-2, TIMP-1, OPN, and GDF-15, and presence of LGE were each significantly associated with worse outcome. Four possible susceptibility loci for cardiac fibrosis in DCM were introduced and underwent eQTL analyses. Rare missense variants in a list of 11 DCM-related genes showed to be associated with the 2 outcome measures or fibrosis burden.

Conclusions

LV-EMB, fibrosis biomarkers, and cMRI likely capture different aspects of a detrimental fibrosis process and may be combined to estimate patients' prognosis and monitor therapeutic success. Phenotype-genotype association studies help elucidate novel disease pathomechanisms and individualize patients' treatment.

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): German Centre for Cardiovascular Research: DZHK

Increased adherence after switch from twice daily calcineurin inhibitor based treatment to once daily modified released tacrolimus in heart transplantation: a pre-experimental study

BACKGROUND

Modified release tacrolimus (TAC) is a new, once-daily oral formulation of the established immunosuppressive agent TAC. Simplification of regimen has been associated with better adherence. This study evaluated patient adherence, as well as safety and efficacy among chronic stable heart transplantation (HT) patients switched from a conventional twice daily calcineurin inhibitor-based regimen (TAC or cyclosporine A [CsA]) to (once daily) modified release TAC.

METHODS

We switched 54 chronic stable patients (41 males and 13 females) from twice daily dosing with conventional TAC or CsA to once daily dosing with modified release TAC. Self-reported adherence was assessed at baseline and at 4 months after the switch using the Basel Assessment of Adherence with Immunosuppressive Medication Scale [BAASIS]), a 4-item validated questionnaire including also a Visual Analogue Scale (VAS). Nonadherence was defined as any self-reported nonadherence on any item.

RESULTS

Modified release TAC was discontinued in 4 patients because of diarrhea (n = 1) or gastrointestinal discomfort (n = 3) leaving 50 evaluable patients. Overall nonadherence at baseline for any of the 4 items was 74% versus 38% after 4 months (P = .0001). Thereafter, adherence improved in 28 patients (56.0%), was unchanged in 18 (36.0%), and decreased in 4 subjects (8.0%). The VAS score improved from 82.3% ± 2.6% to 97.5% ± 4.8% (P < .0001). No significant changes were observed after 4 months regarding hematologic, renal, or liver function parameters (all P = NS).

CONCLUSIONS

Therapeutic regimens for transplant recipients are often complex, contributing to a high incidence of medication nonadherence. This study in chronic, stable, heart transplantation patients demonstrated a significant improvement in patient adherence after a switch to modified release TAC, which was generally well tolerated.

Malignancies after heart transplantation: incidence, risk factors, and effects of calcineurin inhibitor withdrawal

The objectives of the present study were to evaluate the incidence of malignancies and to describe the effects of immunosuppression on survival and recurrence of malignancies after heart transplantation (HTX). Data were analyzed in 211 cardiac allograft recipients, in whom HTX was performed between 1989 and 2005. All of these patients survived for more than 2 years after HTX and received induction therapy with antithymocyte globulin (RATG) guided by T-cell monitoring since 1994. An immunosuppressive regimen consisting of cyclosporine A (CsA) combined with azathioprine was followed by CsA and mycophenolate mofetil (MMF) in 2001; mammalian target of rapamycin (mTOR) inhibitors (everolimus/sirolimus) were used since 2003. Mean patient age at HTX was 51.4 ± 10.5 years; mean follow-up time after HTX 9.2 ± 4.7 years. Overall incidence of neoplasias was 30.8%. Individual risk factors associated with a higher risk of malignancy after HTX were higher age at transplantation (P = .003), male gender (P = .005) and ischemic cardiomyopathy before HTX (P = .04). Administration of azathioprine (P < .0001) or a calcineurin inhibitor (CNI) (P = .02) for more than 1 year was associated with development of malignancy, whereas significantly fewer malignancies were noticed in patients receiving an mTOR-inhibitor (P < .0001). Kaplan-Meier analysis demonstrated a strong statistical trend toward an improved survival in patients with a noncutaneous neoplasia switched to a CNI-free protocol (P = .05). This study demonstrated the impact of a variety of individual risk factors and immunosuppressive drugs on development of malignancy after HTX. Markedly fewer patients with noncutaneous malignancies died after switch to a CNI-free regimen, not quite reaching statistical significance by Kaplan-Meier analysis, however.

Gender and age related predictive value of walk test in heart failure: Do anthropometrics matter in clinical practice?

BACKGROUND

The six-minute walk test (6 WT) is a valid and reliable predictor of morbidity and mortality in chronic heart failure (CHF) patients, frequently used as an endpoint or target in clinical trials. As opposed to spiroergometry, improvement of its prognostic accuracy by correction for height, weight, age and gender has not yet been attempted comprehensively despite known influences of these parameters.

METHODS

We recorded the 6 WT of 1035 CHF patients, attending clinic from 1995 to 2005. The 1-year prognostic value of 6 WT was calculated, alone and after correction for height, weight, BMI and/or age. Analysis was performed on the entire cohort, on males and females separately and stratified according to BMI (<25, 25-30 and >30 kg/m(2)).

RESULTS

6 WT weakly correlated with age (r=-0.32; p<0.0001), height (r=0.2; p<0.0001), weight (r=0.11; p<0.001), not with BMI (r=0.01; p=ns). The 6 WT was a strong predictor of 1-year mortality in both genders, both as a single and age corrected parameter. Parameters derived from correction of 6 WT for height, weight or BMI did not improve the prognostic value in univariate analysis for either gender. Comparison of the receiver operated characteristics showed no significant gain in prognostic accuracy from any derived variable, either for males or females.

CONCLUSION

The six-minute walk test is a valid tool for risk prediction in both male and female CHF patients. In both genders, correcting 6 WT distance for height, weight or BMI alone, or adjusting for age, does not increase the prognostic power of this tool.

Prognostic impact of peakVO2-changes in stable CHF on chronic beta-blocker treatment

BACKGROUND

Peak oxygen uptake (pVO2) is used for risk stratification in chronic heart failure (CHF), but little is known about the prognostic impact of pVO2-changes in patients on chronic beta-blocker (BBL) therapy. We therefore prospectively evaluated individual pVO2-changes at a 6-month interval in patients all receiving BBL.

METHODS

194 patients with stable CHF on stable medication were included (V1) and underwent clinical evaluation and exercise testing. Testing was repeated (V2) at 5.7+/-1.5 months after V1 and patients were followed >12 months after V2. Death or hospitalisation due to cardiac reasons was the predefined EP (EPP, end-point positive; n=62; EPN, end-point negative; n=113).

RESULTS

Initial characteristics did not differ between EPP and EPN. Multivariate cox regression analysis revealed that change of pVO2 (EPP: -0.6+/-2.6 ml/kg min; EPN: +2.5+/-3.3 ml/kg min; p<0.001) was independent to pVO2, LVEF, NTproBNP and NYHA at V2 for prediction of the combined end-point during follow-up. An increase of pVO2 by 10% was identified as an adequate cut-off value for risk stratification and ROC-analysis showed the significant incremental prognostic value of the determination of pVO2 changes in combination with pVO2.

CONCLUSIONS

Serial measurements of pVO2 yield additional information for risk stratification in clinically homogenous CHF patients receiving BBL. This is the first study demonstrating this fact within a narrow predefined interval with all patients on BBL.

[Telemonitoring in chronic heart failure patients. Which diagnostic finding prevents hospital readmission?]

Heart failure exhibits a significant clinical and health economic problem. The implementation of new therapeutic strategies favorably affecting the course of disease is still insufficient in day-to-day practice. Thus, the usage of telemedicine offers a central instrument for service and information, so that an optimized therapy can be achieved by consequent surveillance of the patient with chronic heart disease. Predefined vital parameters are automatically transmitted to the telemedicine center; if individually predefined limits are exceeded, therapeutic means are immediately initiated. For the patient, the center is attainable 24 h throughout the year in case he experiences cardio-pulmonary symptoms. This patient-oriented usage of technology should not replace the physician-patient relationship, but improves and supports the participation and self-management of patients. Furthermore, the results show that this technology can significantly reduce the amount of emergency physician services, hospital admissions and primary care physician visits, and displays for health economics purposes a clearly more cost-effective treatment strategy, while allowing for additional costs inherent to the system. The usage of telemonitoring in chronic heart failure patients may be a trendsetting form of care, which can be used to drastically optimize the information and data flow between patient, hospital and primary care physician individually and at any time.

Exercise capacity and Doppler pressure measurements in symptomatic peripheral arterial obstructive disease

BACKGROUND

Doppler pressure measurements are a useful diagnostic tool in peripheral arterial obstructive disease. The aim of our study was to determine whether these pressure values do predict the degree of impairment of the walking capacity in symptomatic patients.

PATIENTS AND METHODS

We compared the claudication distances (CDI: initial claudication distance, CDA: absolute claudication distance) of 939 patients (63 +/- 11 years) with stable intermittent claudication (Fontaine IIb) with the ankle pressure values at rest (APR) and after exercise (APE), with the ankle/brachial pressure index at rest (ABIR) and after exercise (ABIE), and with the ratio (ABIRATIO = ABIE/ABIR). Ankle systolic pressures were obtained using an 8 MHz Doppler probe. CD was measured by a treadmill test at constant-load conditions (3 km/hr; inclination 12%). Brachial systolic pressures were obtained using an automated blood pressure monitor. The values of the objectively worse leg were correlated with CDI and CDA.

RESULTS

Low Doppler pressure values were not accompanied by significantly shorter walking distances in symptomatic patients. The resting pressure values (APR, ABIR) did not correlate with the claudication distances (CDI: 54 +/- 31 m; CDA: 87 +/- 41 m). For the exercise values (APE, ABIE), even a very slight inverse correlation with the claudication distances was found. In addition, the correlation between the pressure index ratio and the walking distances (ABIRATIO vs. CDI: r = -0.25, p < 0.01; ABIRATIO vs. CDA: r = -0.20, p < 0.01) was inverse, too, but slightly more pronounced.

CONCLUSIONS

In patients with intermittent claudication the ankle artery pressures and the indices derived from these pressure values do not predict the walking distance. Therefore, the decision for angioplasty or bypass surgery should be made with regards to the impairment of quality of life rather than Doppler pressure values.

High frequency intra-QRS signals in idiopathic dilated cardiomyopathy

We extracted and quantified high frequency intra-QRS signals in idiopathic dilated cardiomyopathy (IDC). In IDC the analysis of late potentials in the terminal QRS complex often fails in predicting clinical events because of intraventricular conduction abnormalities and the absence of a circumscribed arrhythmogenic substrate. Therefore, new approaches are required to assess the electrical state of the myocardium. We investigated 21 patients suffering from IDC with (n = 14) and without (n = 7) bundle branch block. High resolution 31 lead magnetocardiograms were filtered with a 67 point 4th order Savitzky-Golay filter. The difference of the measured and filtered signals was calculated (67-200 Hz). The spatio-temporal properties and the areas under the curves of the resulting high frequency intra-QRS signals (IQCs) were studied. We detected IQCs in all patients. The patients had individual patterns regarding the temporal and spatial properties of the IQCs during depolarisation. The IQCs predominantly appeared in the initial portion of the QRS. The ratios of the areas under the curves of the IQCs and the measured signals were linearly correlated to the left ventricular enddiastolic diameter (r = 0.71, significance 0.0012). In IDC the ventricular depolarization is accompanied by individual spatial and temporal patterns of high frequency intra-QRS signals. They can be studied non-invasively from body surface mapping data with the algorithm used in this study. This provides access to the assessment of the electrical status in patients with IDC.

Temporal properties of high frequency intra-QRS signals in myocardial infarction and healthy hearts

The prevalence of late potentials after myocardial infarction depends on the site of the infarction. This may be caused by the different activation onsets of the anterior and inferior myocardial segments. Therefore, in anterior infarcts the high frequency signals may be concealed within the QRS whereas in the inferior infarcts they last beyond the end of the QRS. We compared the timing and the spatial patterns of high frequency intra-QRS signals (IQSs) in the different infarction sites. We investigated 14 patients with anterior infarcts, 17 patients with inferior infarcts, and 10 healthy subjects. 31-lead magnetocardiograms were recorded in left precordial position and averaged. The QRS signals were smoothed with a Savitzky-Golay filter. The smoothed QRS signals were subtracted from the measured ones. The difference of the signals (frequency band of about 60-200 Hz) representing the high frequency components was quantified. The percentage of the high frequency signals was calculated for the entire QRS, for the first and for the second half, respectively. We found that in patients with anterior infarcts the high frequency components predominantly appeared in the first half of the QRS whereas in inferior infarcts these components predominantly appeared in the second half of the QRS. The different infarction sites were associated with different spatial patterns of the high frequency signals on the body surface. In healthy subjects there was not such a preferential association of time intervals and high frequency signals. Late potentials are the special case of high frequency signals appearing in the terminal QRS. It is the general property of the myocardium to generate high frequency signals associated with the depolarization of infarcted tissue. The timing of such signals and the spatial distribution patterns on the body surface may help to identify the location of the sources.