Heart Failure with Preserved Ejection Fraction (hfpef) Pathophysiology Study (IDENTIFY-HF): Does Increased Arterial Stiffness Associate with HFpEF, in Addition to Ageing and Vascular Effects of Comorbidities? Rationale and Design

AimsComorbidities play a significant role towards the pathophysiology of heart failure with preserved ejection fraction (HFpEF), characterized by abnormal macrovascular function and altered ventricular-vascular coupling. However, our understanding of the role of comorbidities and arterial stiffness in HFpEF remains incomplete. We hypothesized that HFpEF is preceded by a cumulative rise in arterial stiffness as cardiovascular comorbidities accumulate, beyond that associated with ageing. Methods and resultsArterial stiffness was assessed using pulse wave velocity (PWV) in five groups: Group A, healthy volunteers (n = 21); Group B, patients with hypertension (n = 21); Group C, hypertension and diabetes mellitus (n = 20); Group D, HFpEF (n = 21); and Group E, HF with reduced ejection fraction (HFrEF) (n = 11). All patients were aged 70 and above. Mean PWV increased from Groups A to D (PWV 10.2, 12.2, 13.0, and 13.7 m/s, respectively) as vascular comorbidities accumulated independent of age, renal function, haemoglobin, obesity (body mass index), smoking status, and hypercholesterolaemia. HFpEF exhibited the highest PWV and HFrEF displayed near-normal levels (13.7 vs. 10 m/s, P = 0.003). PWV was inversely related to peak oxygen consumption (r = -0.304, P = 0.03) and positively correlated with left ventricular filling pressures (E/e ') on echocardiography (r = -0.307, P = 0.014). ConclusionsThis study adds further support to the concept of HFpEF as a disease of the vasculature, underlined by an increasing arterial stiffness that is driven by vascular ageing and accumulating vascular comorbidities, for example, hypertension and diabetes. Reflecting a pulsatile arterial afterload associated with diastolic dysfunction and exercise capacity, PWV may provide a clinically relevant tool to identify at-risk intermediate phenotypes (e.g. pre-HFpEF) before overt HFpEF occurs.