The Diagnosis and Management of Heart Failure across Primary and Secondary Care

Abstract

This thesis is centred on the complex arena of heart failure diagnosis and management across the primary-secondary care interface, including service delivery models and the utility of natriuretic peptides in triage of patients. The thesis combines qualitative and quantitative methodologies to identify barriers to heart failure care and to test strategies for overcoming these. The findings were:1. GPs found heart failure difficult to diagnose and treat due to clinical uncertainty, lack of awareness of the relevant research evidence and organisational issues including lack of access to diagnostics.2. With regard to specialists variable opinions and practice in diagnosis and management of heart failure in hospitals and across primary- secondary care were confirmed, these centred on diagnostic difficulties, treatment issues and service delivery problems.3. A GP-specialist led one-stop diagnostic clinic facilitated expedient, accurate diagnosis of left ventricular systolic dysfunction.4. An integrated heart failure service across primary and secondary care delivered evidence based therapy, patient and carer education and access to social and palliative care for patients with heart failure.5. Natriuretic peptide measurement had high negative predictive value for excluding heart failure in a consecutive GP referred cohort.6. Electrocardiography was not as accurate at excluding heart failure as suggested by national guidelines. 7. Use of N-terminal pro B-type natriuretic peptide as a pre-screening test for secondary care referral may have reduced potential referrals, but the low specificity of the test and high prevalence of confounding factors in the screened population increased demand on diagnostic services and did not lead to cost savings. Conclusions The diagnostic and treatment difficulties identified by GPs and hospital specialists are dependent on a complex interplay of patient, clinician and organisational factors. Barriers need to be overcome in locality specific and multi-faceted implementation strategies across primary-secondary care. This thesis described an integrated heart failure diagnosis and management system that overcame these barriers and delivered accurate diagnosis and modern evidence based treatment. The relatively poor positive predictive value and low specificity of natriuretic peptides in real life practice meant that large numbers of patients with raised BNP/NT proBNP did not have heart failure due to left ventricular systolic dysfunction. This thesis demonstrated that the prognostic power of BNP/NT proBNP extended beyond LVSD to most cardiac conditions. Ideally, all patients with raised natriuretic peptides deserve a full cardiac assessment including echocardiography, followed by optimal use of evidenced based pharmacotherapy and health professional support. We need to find ways of providing expedient diagnostic and treatment services to these patients especially in rationed health care systems such as the NHS. Until this issue is addressed widespread natriuretic peptide use is unlikely within the UK.