Invasive Assessment of Pulmonary Hypertension
Time for a More Fluid Approach?
- heart failure
- heart failure with preserved ejection fraction
- pulmonary hypertension
Pulmonary hypertension (PH) is a significant public health problem that may develop from abnormalities in the pulmonary vasculature, with left-sided heart failure (HF), high cardiac output states, or any combination of these.1,2 The commonest cause is HF (group 2 PH),3 although many clinicians continue to associate the term PH with the much smaller cohort of patients with isolated pulmonary vascular disease (group 1 PH). A host of efficacious therapies improve outcome in group 1 PH, and when on appropriate treatment, this subgroup enjoys the highest survival rates. In contrast, group 2 PH is associated with the worst outcomes.3 Although trials are underway, there is currently no established treatment for group 2 PH, and some pulmonary vasodilators may even worsen outcome in patients with HF.1 Thus, distinction of these entities is of paramount importance.
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Groups 1 and 2 are distinguished by the pulmonary capillary wedge pressure (PCWP), which is elevated (>15 mm Hg) in the latter and normal in the former.1,2 Accurate noninvasive assessment of PCWP is difficult,4 but if there is a low ejection fraction (EF) or significant left-sided valve disease, the diagnosis of group 2 PH is generally rendered with confidence.1,2 The more difficult distinction is between group 1 PH and PH caused by HF with preserved EF (HFpEF).5 Diagnosis of HFpEF is problematic because of the difficulty in noninvasively assessing PCWP and because PCWP is often normal at rest and elevated only during physiological stresses such as exercise6 or volume expansion.7 As such, current guidelines recommend provocative testing (exercise or saline loading) to distinguish HFpEF from group 1 PH among individuals with normal PCWP and typical HFpEF risk factors,2 although there has been little data to support …