Learning Interpretable Anatomical Features Through Deep Generative Models: Application to Cardiac Remodeling

Alterations in the geometry and function of the heart define well-established causes of cardiovascular disease. However, current approaches to the diagnosis of cardiovascular diseases often rely on subjective human assessment as well as manual analysis of medical images. Both factors limit the sensitivity in quantifying complex structural and functional phenotypes. Deep learning approaches have recently achieved success for tasks such as classification or segmentation of medical images, but lack interpretability in the feature extraction and decision processes, limiting their value in clinical diagnosis. In this work, we propose a 3D convolutional generative model for automatic classification of images from patients with cardiac diseases associated with structural remodeling. The model leverages interpretable task-specific anatomic patterns learned from 3D segmentations. It further allows to visualise and quantify the learned pathology-specific remodeling patterns in the original input space of the images. This approach yields high accuracy in the categorization of healthy and hypertrophic cardiomyopathy subjects when tested on unseen MR images from our own multi-centre dataset (100%) as well on the ACDC MICCAI 2017 dataset (90%). We believe that the proposed deep learning approach is a promising step towards the development of interpretable classifiers for the medical imaging domain, which may help clinicians to improve diagnostic accuracy and enhance patient risk-stratification

Body surface area and baseline blood pressure predict subclinical anthracycline cardiotoxicity in women treated for early breast cancer.

BACKGROUND AND AIMS: Anthracyclines are highly effective chemotherapeutic agents which may cause long-term cardiac damage (chronic anthracycline cardiotoxicity) and heart failure. The pathogenesis of anthracycline cardiotoxicity remains incompletely understood and individual susceptibility difficult to predict. We sought clinical features which might contribute to improved risk assessment. METHODS: Subjects were women with early breast cancer, free of pre-existing cardiac disease. Left ventricular ejection fraction was measured using cardiovascular magnetic resonance before and >12 months after anthracycline-based chemotherapy (>3 months post-Trastuzumab). Variables associated with subclinical cardiotoxicity (defined as a fall in left ventricular ejection fraction of ≥5%) were identified by logistic regression. RESULTS: One hundred and sixty-five women (mean age 48.3 years at enrollment) completed the study 21.7 months [IQR 18.0-26.8] after starting chemotherapy. All received anthracyclines (98.8% epirubicin, cumulative dose 400 [300-450] mg/m2); 18% Trastuzumab. Baseline blood pressure was elevated (≥140/90mmHg, mean 147.3/86.1mmHg) in 18 subjects. Thirty-four subjects (20.7%) were identified with subclinical cardiotoxicity, independent predictors of which were the number of anthracycline cycles (odds ratio, OR 1.64 [1.17-2.30] per cycle), blood pressure ≥140/90mmHg (OR 5.36 [1.73-17.61]), body surface area (OR 2.08 [1.36-3.20] per standard deviation (0.16m2) increase), and Trastuzumab therapy (OR 3.35 [1.18-9.51]). The resultant predictive-model had an area under the receiver operating characteristics curve of 0.78 [0.70-0.86]. CONCLUSIONS: We found subclinical cardiotoxicity to be common even within this low risk cohort. Risk of cardiotoxicity was associated with modestly elevated baseline blood pressure-indicating that close attention should be paid to blood pressure in patients considered for anthracycline based chemotherapy. The association with higher body surface area suggests that indexing of anthracycline doses to surface area may not be appropriate for all, and points to the need for additional research in this area

Sleep-disordered breathing-do we have to change gears in heart failure?

The majority of patients with heart failure have sleep-disordered breathing (SDB)-with central (rather than obstructive) sleep apnoea becoming the predominant form in those with more severe disease. Cyclical apnoeas and hypopnoeas are associated with sleep disturbance, hypoxaemia, haemodynamic changes, and sympathetic activation. Such patients have a worse prognosis than those without SDB. Mask-based therapies of positive airway pressure targeted at SDB can improve measures of sleep quality and partially normalise the sleep and respiratory physiology, but recent randomised trials of cardiovascular outcomes in central sleep apnoea have been neutral or suggested the possibility of harm, likely from increased sudden death. Further randomised outcome studies (with cardiovascular mortality and hospitalisation endpoints) are required to determine whether mask-based treatment for SDB is appropriate for patients with chronic systolic heart failure and obstructive sleep apnoea, for those with heart failure with preserved ejection fraction, and for those with decompensated heart failure. New therapies for sleep apnoea-such as implantable phrenic nerve stimulators-also require robust assessment. No longer can the surrogate endpoints of improvement in respiratory and sleep metrics be taken as adequate therapeutic outcome measures in patients with heart failure and sleep apnoea

Adherence to the European Society of Cardiology (ESC) guidelines for chronic heart failure - A national survey of the cardiologists in Pakistan

<p>Abstract</p> <p>Background</p> <p>The aims of this study were to evaluate the awareness of and attitudes towards the 2005 European Society of Cardiology (ESC) guidelines for Heart Failure (HF) of the cardiologists in Pakistan and assess barriers to adherence to guidelines.</p> <p>Methods</p> <p>A cross-sectional survey was conducted in person from March to July 2009 to all cardiologists practicing in 4 major cities in Pakistan (Karachi, Lahore, Quetta and Peshawar). A validated, semi-structured questionnaire assessing ESC 2005 Guidelines for HF was used to obtain information from cardiologists. It included questions about awareness and relevance of HF guidelines (See Additional File <supplr sid="S1">1</supplr>). Respondents' management choices were compared with those of an expert panel based on the guidelines for three fictitious patient cases. Cardiologists were also asked about major barriers to adherence to guidelines.</p> <suppl id="S1"> <title> <p>Additional file 1</p> </title> <text> <p><b>Questionnaire</b>. Description: Questionnaire that was administered to participants.</p> </text> <file name="1471-2261-11-68-S1.DOC"> <p>Click here for file</p> </file> </suppl> <p>Results</p> <p>A total of 372 cardiologists were approached; 305 consented to participate (overall response rate, 82.0%). The survey showed a very high awareness of CHF guidelines; 97.4% aware of any guideline. About 13.8% considered ESC guidelines as relevant or very relevant for guiding treatment decisions while 92.8% chose AHA guidelines in relevance. 87.2% of respondents perceived that they adhered to the HF guidelines. For the patient cases, the proportions of respondents who made recommendations that completely matched those of the guidelines were 7% (Scenario 1), 0% (Scenario 2) and 20% (Scenario 3). Respondents considered patient compliance (59%) and cost/health economics (50%) as major barriers to guideline implementation.</p> <p>Conclusion</p> <p>We found important self reported departures from recommended HF management guidelines among cardiologists of Pakistan.</p

Running Title: Heart Function Clinic Access -Realist Review

Rationale, aim, and objectives Heart failure (HF) clinics are highly effective, yet not optimally utilized. A realist review was performed to identify contexts (eg, health system characteristics, clinic capacity, and siting) and underlying mechanisms (eg, referring provider knowledge of clinics and referral criteria, barriers in disadvantaged patients) that influence utilization (provider referral [ie, of all appropriate and no inappropriate patients] and access [ie, patient attends ≥1 visit]) of HF clinics. Methods Following an initial scoping search and field observation in a HF clinic, we developed an initial program theory in conjunction with our expert panel, which included patient partners. Then, a literature search of seven databases was searched from inception to December 2019, including Medline; Grey literature was also searched. Studies of any design or editorials were included; studies regarding access to cardiac rehabilitation, or a single specialist for example, were excluded. Two independent reviewers screened the abstracts, and then full‐texts. Relevant data from included articles were used to refine the program theory. Results A total of 29 papers from five countries (three regions) were included. There was limited information to support or refute many elements of our initial program theory (eg, referring provider knowledge/beliefs, clinic inclusion/exclusion criteria), but refinements were made (eg, specialized care provided in each clinic, lack of patient encouragement). Lack of capacity, geography, and funding arrangements were identified as contextual factors, explaining a range of mechanistic processes, including patient clinical characteristics and social determinants of health as well as clinic characteristics that help to explain inappropriate and low use of HF clinics (outcome). Conclusion Given the burden of HF and benefit of HF clinics, more research is needed to understand, and hence overcome sub‐optimal use of HF clinics. In particular, an understanding from the perspective of referring providers is needed

A cluster randomized controlled trial of a clinical pathway for hospital treatment of heart failure: study design and population

<p>Abstract</p> <p>Background</p> <p>The hospital treatment of heart failure frequently does not follow published guidelines, potentially contributing to the high morbidity, mortality and economic cost of this disorder. Consequently the development of clinical pathways has the potential to reduce the current variability in care, enhance guideline adherence, and improve outcomes for patients. Despite enthusiasm and diffusion, the widespread acceptance of clinical pathways remain questionable because very little prospective controlled data demonstrated their effectiveness. The Experimental Prospective Study on the Effectiveness and Efficiency of the Implementation of Clinical Pathways was designed in order to conduct a rigorous evaluation of clinical pathways in hospital treatment of acute heart failure. The primary objective of the trial was to evaluate the effectiveness of the implementation of clinical pathways for hospital treatment of heart failure in Italian hospitals.</p> <p>Methods/design</p> <p>Two-arm, cluster-randomized trial. 14 community hospitals were randomized either to arm 1 (clinical pathway: appropriate use of practice guidelines and supplies of drugs and ancillary services, new organization and procedures, patient education, etc.) or to arm 2 (no intervention, usual care). 424 patients sample (212 in each group), 80% of power at the 5% significance level (two-sided). The primary outcome measure is in-hospital mortality. We will also analyze the impact of the clinical pathways comparing the length and the appropriateness of the stay, the rate of unscheduled readmissions, the customers' satisfaction and the costs treating the patients with the pathways and with the current practice along all the observation period. The quality of the care will be assessed by monitoring the use of diagnostic and therapeutic procedures during hospital stay and by measuring key quality indicators at discharge.</p> <p>Discussion</p> <p>This paper examines the design of the evaluation of a complex intervention. Since clinical pathways are made up of various interconnecting parts we have chosen the cluster-randomized controlled trial because is widely accepted as the most reliable method of determining effectiveness when measuring cost-effectiveness in real practice.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov ID [NCT00519038]</p