Effects of Beta-Blocker Therapy and Phosphodiesterase Inhibition on Cardiac Neurohormonal Activation

Previous clinical investigations have demonstrated the utility of β-adrenergic blockade in reducing perioperative ischaemic events, ultimately translating into a decrease in cardiac morbidity and mortality. However, β-blocker therapy remains underutilized in clinical practice because of concerns of potential adverse effects such as a reduced inotropic state, which might result in acute congestive heart failure or hypotension. Therefore, additional treatment with a positive inotropic agent might be needed. Phosphodiesterase inhibitors (PDEIs) offer a favourable pharmacological profile in this setting and stimulate cardiac function in the absence of the β-adrenergic receptor. We hypothesize that the combination of PDEI and β-blocker therapy would decrease perioperative plasma concentrations of brain natriuretic peptide (BNP) in patients requiring major vascular surgery. BNP is chosen as our primary outcome variable because of its importance as a sensitive correlate of myocardial dysfunction and its prognostic value for predicting the risk of cardiac death across the entire spectrum of acute coronary syndromes.