Invasive Hemodynamic and Metabolic Evaluation of HFpEF

Heart failure with preserved ejection fraction (HFpEF) is a complex and heterogeneous condition of multiple causes, characterized by a clinical syndrome resulting from elevated left ventricular filling pressures, with an apparently unimpaired left ventricular systolic function. Although HFpEF has been long recognized as a distinct entity with significant morbidity for patients, its diagnosis remains challenging to this day. In recent years, few diagnostic algorithms have been postulated to aid in the identification of this condition. Invasive hemodynamic and metabolic evaluation is often warranted for the conclusive diagnosis and risk stratification of HFpEF, in patients presenting with undifferentiated DOE.

Rest and provoked hemodynamics remain the golden-standard diagnostic tool to unequivocally confirm the diagnosis of both established and incipient HFpEF, respectively. Cycle exercise hemodynamics is the paramount provocative maneuver to unveil this condition. Rapid saline loading does not offer a significant benefit over that of cycle exercise. Vasoactive agents can also uncover and confirm incipient HFpEF disease. The role of metabolic evaluation in patients presenting with idiopathic dyspnea on exertion (DOE) is of unparalleled value for those who have expertise in cardiopulmonary exercise test (CPET) interpretation; however, the average clinician who focuses solely on oxygen consumption will find it underwhelming. Invasive CPET stands alone as the ultimate diagnostic tool to discriminate between pulmonary, cardiovascular, and skeletal muscle disorders, and their respective contribution to DOE and exercise intolerance.

Several hemodynamic and metabolic parameters have demonstrated not only strong diagnostic value, but also predictive power in HFpEF. Additionally, these diagnostic methods have given rise to several therapeutic interventions that are now part of our clinical armamentarium. Regrettably, due to the heterogeneity and multicausality of HFpEF, none of the targeted interventions have been so far successful in decreasing the mortality burden of this prevalent condition.