Secondary and Tertiary Prevention at Different Stages in the Development of Heart Failure

Abstract

Heart failure (HF), an important public health problem, is associated with high mortality and morbidity. Today, the spiralling cost of HF, due to hospitalisations and universal provision of evidence-based therapy, is unmanageable. This makes HF prevention, along a continuum starting with risk factors, a priority. The key challenges include recognition and control of antecedent conditions, early detection and treatment of subclinical disease, and limiting disease progression. This thesis, which is presented in two sections, aims to enhance early detection of heart disease in high-risk individuals and improve risk stratification in those with established heart disease. Part A is based on the Natriuretic Peptides in the Community 2 study, which had a prospective cross-sectional design. It compared the utility of NT-proBNP with electrocardiography for the detection of left ventricular hypertrophy among patients with type 2 diabetes mellitus (T2DM) without cardiovascular disease. A total of 375 participants were recruited between 2006 and 2007. The key finding is that previously undetected structural heart disease is common in this cohort, leading to an underestimation of cardiovascular risk. Both tests evaluated in this study (electrocardiography and NT-proBNP) were insensitive and unsuitable for screening. Routine echocardiography for all individuals with T2DM may be more appropriate than a screening test, given the high prevalence of disease. Part B contains 3 literature-based meta-analyses undertaken using standardised methodology. It focuses on assessing risk of disease progression in HF. Prospective observational studies reporting the outcomes of interest (death and HF hospitalisation) were included. Echocardiographic measures of left ventricular systolic (ejection fraction) and diastolic (mitral filling pattern) function were shown to predict mortality and HF morbidity. These data support the routine measurement of the studied parameters and their use in evaluating prognosis. Heart failure remains one of the most burdensome cardiovascular conditions to manage. Patients with HF are heterogeneous and have multiple comorbidities. Identification of those at risk of initial and recurrent hospitalisation requires a multi-pronged approach, incorporating both clinical and echocardiographic parameters. The contribution of each varies over the disease spectrum. An understanding of this complex nature will ultimately lead to enhanced management and improved survival amongst patients with HF.