KBTBD13 is a novel cardiomyopathy gene

KBTBD13 variants cause nemaline myopathy type 6 (NEM6). The majority of NEM6 patients harbors the Dutch founder variant, c.1222C>T, p.Arg408Cys (KBTBD13 p.R408C). Although KBTBD13 is expressed in cardiac muscle, cardiac involvement in NEM6 is unknown. Here, we constructed pedigrees of three families with the KBTBD13 p.R408C variant. In 65 evaluated patients, 12% presented with left ventricle dilatation, 29% with left ventricular ejection fraction< 50%, 8% with atrial fibrillation, 9% with ventricular tachycardia, and 20% with repolarization abnormalities. Five patients received an implantable cardioverter defibrillator, three cases of sudden cardiac death were reported. Linkage analysis confirmed cosegregation of the KBTBD13 p.R408C variant with the cardiac phenotype. Mouse studies revealed that (1) mice harboring the Kbtbd13 p.R408C variant display mild diastolic dysfunction; (2) Kbtbd13-deficient mice have systolic dysfunction. Hence, (1) KBTBD13 is associated with cardiac dysfunction and cardiomyopathy; (2) KBTBD13 should be added to the cardiomyopathy gene panel; (3) NEM6 patients should be referred to the cardiologist.

The use of a probe stabilizer to reduce musculoskeletal overload of ultrasound operators in routine diagnostic echocardiographic imaging

Introduction: Echocardiography is essential in the evaluation of patients with cardiovascular disease. Repetitive movements, however, expose ultrasound operators to a high risk of musculoskeletal strain injuries. Aim: We investigated to what extent a probe stabilizer could reduce repetitive movements. Materials and methods: The study population consisted of 31 male patients referred for routine transthoracic echocardiography. A good apical acoustic window was prerequisite for inclusion. Standard apical views and measurements were first recorded without using the probe stabilizer. Afterwards, the same apical views and measurements were acquired with utilization of the probe stabilizer. During the entire procedure, shoulder abduction and muscle activity of right forearm flexor and extensor muscles were recorded. To this purpose, an EMG-sensor was attached to the right lower arm and a gyroscope to the right shoulder blade. Results: Extreme right arm abduction (>30˚) occurred in 58% of the time with use of the stabilizer and in 98% of the time without (p <0.01). Activity of right forearm extensor muscles was 42% with and 60% without stabilizer (p = 0.04). For the flexor muscles these percentages were 47% and 87%, respectively (p <0.01). Use of the stabilizer did not affect the time needed for image acquisition (308s versus 309s, respectively, p = 0.46). Conclusions: This study demonstrated that the use of a stabilizer during acquisition of apical views in routine transthoracic echocardiography reduces the total time of shoulder abduction and the use of the right forearm muscles, while acquisition time was not affected.

Geriatric rehabilitation in older patients with cardiovascular disease: a feasibility study

PURPOSE

Cardiac rehabilitation in older patients after hospitalization because of cardiovascular disease is recommended. However, many older patients do not receive cardiac rehabilitation in daily practice, due to lack of referral and poor adherence. This can be related to impaired clinical and functional status of these patients, who are more likely to present with frailty, frequent comorbidities, and disability. Geriatric rehabilitation might be a possible solution to reduce barriers to cardiac rehabilitation attendance. We developed and implemented an inpatient geriatric rehabilitation programme that was provided immediately after discharge from the hospital, for older patients with a significant functional decline during hospital admission because of cardiovascular disease: 'the GR-cardio programme'. The primary aim of the present study is to investigate feasibility of the GR-cardio programme.

METHODS

This is a retrospective real-life feasibility study describing a consecutive series of older patients receiving the GR-cardio programme, with no control group. All patients had been hospitalized because of cardiovascular disease. Data on patient characteristics, functional status, health-related quality of life (HRQoL), readmissions, and mortality were collected from the patients file on admission, at discharge and 6 months after discharge from the GR-cardio programme. Feasibility of the programme was evaluated using the following outcomes: recruitment, resulting sample characteristics, safety, and preliminary evaluation of patients' responses to the GR-cardio programme.

RESULTS

In total, 58 patients [mean age 78.8 (± 9.8) years; 43% male] were included in the study. On admission, functional status and HRQoL were severely impaired but showed clinically relevant improvements. During the programme, three patients died. Eighty-three percent of all patients were discharged back home after completing the rehabilitation programme with a mean length of 38 days. Mortality rate during follow-up was the highest in patients with heart failure (32%).

CONCLUSIONS

This study indicates that geriatric rehabilitation for patients with cardiovascular disease is feasible. Furthermore, our results show that the GR-cardio programme can probably offer substantial benefits for patients in terms of improving functional status and HRQoL.

Truncating titin mutations are associated with a mild and treatable form of dilated cardiomyopathy

AIMS

Truncating titin mutations (tTTN) occur in 25% of dilated cardiomyopathy (DCM) cases, but the phenotype and severity of disease they cause have not yet been systematically studied. We studied whether tTTN variants are associated with a clinically distinguishable form of DCM.

METHODS AND RESULTS

We compared clinical data on DCM probands and relatives with a tTTN mutation (n = 45, n = 73), LMNA mutation (n = 28, n = 29), and probands who tested negative for both genes [idiopathic DCM (iDCM); n = 60]. Median follow-up was at least 2.5 years in each group. TTN subjects presented with DCM at higher age than LMNA subjects (probands 47.9 vs. 40.4 years, P = 0.004; relatives 59.8 vs. 47.0 years, P = 0.01), less often developed LVEF <35% [probands hazard ratio (HR) 0.38, P = 0.002], had higher age of death (probands 70.4 vs. 59.4 years, P < 0.001; relatives 74.1 vs. 58.4 years, P = 0.008), and had better composite outcome (malignant ventricular arrhythmia, heart transplantation, or death; probands HR 0.09, P < 0.001; relatives HR 0.21, P = 0.02) than LMNA subjects and iDCM subjects (HR 0.36, P = 0.07). An LVEF increase of at least 10% occurred in 46.9% of TTN subjects after initiation of standard heart failure treatment, while this only occurred in 6.5% of LMNA subjects (P < 0.001) and 18.5% of iDCM subjects (P = 0.02). This was confirmed in families with co-segregation, in which the 10% point LVEF increase occurred in 55.6% of subjects (P = 0.003 vs. LMNA, P = 0.079 vs. iDCM).

CONCLUSIONS

This study shows that tTTN-associated DCM is less severe at presentation and more amenable to standard therapy than LMNA mutation-induced DCM or iDCM.

Incremental prognostic power of novel biomarkers (growth-differentiation factor-15, high-sensitivity C-reactive protein, galectin-3, and high-sensitivity troponin-T) in patients with advanced chronic heart failure

Elevated natriuretic peptides provide strong prognostic information in patients with heart failure (HF). The role of novel biomarkers in HF needs to be established. Our objective was to evaluate the prognostic power of novel biomarkers, incremental to the N-terminal portion of the natriuretic peptide (NT-proBNP) in chronic HF. Concentrations of circulating NT-proBNP, growth differentiation factor 15 (GDF-15), high-sensitivity C-reactive protein (hs-CRP), galectin-3 (Gal-3), and high-sensitivity troponin T (hs-TnT) were measured and related to all-cause long-term mortality. Of 209 patients (age 71 ± 10 years, 73% male patients, 97% New York Heart Association class III), 151 (72%) died during a median follow-up of 8.7 ± 1 year. The calculated area under the curve for NT-proBNP was 0.63, GDF-15 0.78, hs-CRP 0.66, Gal-3 0.68, and hs-TnT 0.68 (all p <0.01). Each marker was predictive for mortality in univariate analysis. In multivariate analysis, elevated concentrations of GDF-15 (hazard ratio [HR] 1.41, confidence interval [CI] 1.1 to 178, p = 0.005), hs-CRP (HR 1.38, CI 1.15 to 1.67, p = 0.001), and hs-TnT (HR 1.27, CI 1.06 to 1.53, p = 0.008) were independently related to mortality. All novel markers had an incremental value to NT-proBNP, using the integrated discrimination improvement. In conclusion, in chronic HF, GDF-15, hs-CRP, and hs-TnT are independent prognostic markers, incremental to NT-proBNP, in predicting long-term mortality. In this study, GDF-15 is the most predictive marker, even stronger than NT-proBNP.

Galectin-3 is an independent marker for ventricular remodeling and mortality in patients with chronic heart failure

BACKGROUND

Galectin-3 (Gal-3) is a recently discovered marker for myocardial fibrosis and elevated levels are associated with an impaired outcome after short-term follow-up in heart failure (HF) patients. However, whether Gal-3 is related to cardiac remodeling and outcome after long-term follow-up is unknown. Therefore, we determined the utility of Gal-3 as a novel biomarker for left ventricular remodeling and long-term outcome in patients with severe chronic HF.

METHODS AND RESULTS

A total of 240 HF patients with New York Heart Association (NYHA) Class III and IV were included. Patients were followed for 8.7 ± 1 years, had a mean age of 71 ± 0.6 years and 73 % of the study population was male. Circulating levels of NT-proBNP and Gal-3 were measured. Serial echocardiography was performed at baseline and at 3 months. At baseline median left ventricular end-diastolic volume (LVEDV) was 267 mL [interquartile range 232-322]. Patients were divided into three groups according to the change in LVEDV. Patients in whom the LVEDV decreased over time had significant lower levels of Gal-3 at entry compared to patients in whom the LVEDV was stable or increased (14.7 vs. 17.9 vs. 19.0 ng/mL; p = 0.004 for trend), whereas no significant differences were seen in levels of NT-proBNP (p = 0.33). Multivariate linear regression analyses revealed that Gal-3 levels were positively correlated to change in LVEDV (p = 0.007). In addition, Gal-3 was a significant predictor of mortality after long-term follow-up (p = 0.001).

CONCLUSION

Gal-3 is associated with left ventricular remodeling determined by serial echocardiography and predicts long-term mortality in patients with severe chronic HF.

The diagnostic value of physical examination and additional testing in primary care patients with suspected heart failure

BACKGROUND

Early diagnosis of nonacute heart failure is crucial because prompt initiation of evidence-based treatment can prevent or slow down further progression. To diagnose new-onset heart failure in primary care is challenging.

METHODS AND RESULTS

This is a cross-sectional diagnostic accuracy study with external validation. Seven hundred twenty-one consecutive patients suspected of new-onset heart failure underwent standardized diagnostic work-up including chest x-ray, spirometry, ECG, N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurement, and echocardiography in specially equipped outpatient diagnostic heart failure clinics. The presence of heart failure was determined by an outcome panel using the initial clinical data and 6-month follow-up data, blinded to biomarker data. Of the 721 patients, 207 (28.7%) had heart failure. The combination of 3 items from history (age, coronary artery disease, and loop diuretic use) plus 6 from physical examination (pulse rate and regularity, displaced apex beat, rales, heart murmur, and increased jugular vein pressure) showed independent diagnostic value (c-statistic 0.83). NT-proBNP was the most powerful supplementary diagnostic test, increasing the c-statistic to 0.86 and resulting in net reclassification improvement of 69% (P<0.0001). A simplified diagnostic rule was applied to 2 external validation datasets, resulting in c- statistics of 0.95 and 0.88, confirming the results.

CONCLUSIONS

In this study, we estimated the quantitative diagnostic contribution of elements of the history and physical examination in the diagnosis of heart failure in primary care outpatients, which may help to improve clinical decision making. The largest additional quantitative diagnostic contribution to those elements was provided by measurement of NT-proBNP. For daily practice, a diagnostic rule was derived that may be useful to quantify the probability of heart failure in patients with new symptoms suggestive of heart failure.

Added value of a physician-and-nurse-directed heart failure clinic: results from the Deventer-Alkmaar heart failure study

AIM

To determine whether an intensive intervention at a heart failure (HF) clinic by a combination of a clinician and a cardiovascular nurse, both trained in HF, reduces the incidence of hospitalisation for worsening HF and/or all-cause mortality (primary end point) and improves functional status (including left ventricular ejection fraction, New York Heart Association (NYHA) class and quality of life) in patients with NYHA class III or IV.

SETTING

Two regional teaching hospitals in The Netherlands.

METHODS

240 patients were randomly allocated to the 1-year intervention (n = 118) or usual care (n = 122). The intervention consisted of 9 scheduled patient contacts-at day 3 by telephone, and at weeks 1, 3, 5, 7 and at months 3, 6, 9 and 12 by a visit-to a combined, intensive physician-and-nurse-directed HF outpatient clinic, starting within a week after hospital discharge from the hospital or referral from the outpatient clinic. Verbal and written comprehensive education, optimisation of treatment, easy access to the clinic, recommendations for exercise and rest, and advice for symptom monitoring and self-care were provided. Usual care included outpatient visits initialized by individual cardiologists in the cardiology departments involved and applying the guidelines of the European Society of Cardiology.

RESULTS

During the 12-month study period, the number of admissions for worsening HF and/or all-cause deaths in the intervention group was lower than in the control group (23 vs 47; relative risk (RR) 0.49; 95% confidence interval (CI) 0.30 to 0.81; p = 0.001). There was an improvement in left ventricular ejection fraction (LVEF) in the intervention group (plus 2.6%) compared with the usual care group (minus 3.1%; p = 0.004). Patients in the intervention group were hospitalised for a total of 359 days compared with 644 days for those in the usual care group. Beneficial effects were also observed on NYHA classification, prescription of spironolactone, maximally reached dose of beta-blockers, quality of life, self-care behaviour and healthcare costs.

CONCLUSION

A heart failure clinic involving an intensive intervention by both a clinician and a cardiovascular nurse substantially reduces hospitalisations for worsening HF and/or all-cause mortality and improves functional status, while decreasing healthcare costs, even in a country with a primary-care-based healthcare system.

Heart failure programmes in countries with a primary care-based health care system. Are additional trials necessary? Design of the DEAL-HF study

BACKGROUND

Several randomised studies of heart failure (HF) management programmes in the United States, Australia and Europe have shown a considerable reduction in hospitalisation rates for HF. In this article, a comprehensive review of these studies will be provided and their applicability to countries, with a primary care-based healthcare system, will be discussed. In addition, the design of the Deventer-Alkmaar HF Project (DEAL-HF), a randomised study of the effect of a nurse and physician-directed intervention over 1 year in The Netherlands, will also be presented.

AIM

To discuss the applicability of the results of available studies on heart failure management programmes to countries with well-structured primary care facilities and to determine whether additional trials should be conducted in these countries.

METHODS

We performed a literature search in PubMed. In a review of the available studies, essential methodological aspects, in particular, the population involved, the sample size, follow-up period, setting, type of intervention, and the outcome parameters, are discussed critically. Also, the applicability of these studies to countries with a primary care-based healthcare system and easy access to medical care is evaluated.

CONCLUSION

Applicability of the results of the available studies on the efficacy of heart failure management programmes to countries with a primary care-based health care system is doubtful. An efficacy trial in a country with a well-established primary care-based healthcare system, such as The Netherlands, is due to report soon (DEAL-HF).

Ring vaccination and smallpox control

We present a stochastic model for the spread of smallpox after a small number of index cases are introduced into a susceptible population. The model describes a branching process for the spread of the infection and the effects of intervention measures. We discuss scenarios in which ring vaccination of direct contacts of infected persons is sufficient to contain an epidemic. Ring vaccination can be successful if infectious cases are rapidly diagnosed. However, because of the inherent stochastic nature of epidemic outbreaks, both the size and duration of contained outbreaks are highly variable. Intervention requirements depend on the basic reproduction number R₀, for which different estimates exist. When faced with the decision of whether to rely on ring vaccination, the public health community should be aware that an epidemic might take time to subside even for an eventually successful intervention strategy.