Prognostic impact of hemodynamic response to adenosine in patients older than age 55 years undergoing vasodilator stress myocardial perfusion study

Background - The prognostic importance of various hemodynamic responses to adenosine infusion in patients undergoing adenosine stress myocardial perfusion stress (MPS) has not been defined. Methods and Results - We identified 3444 unique patients (53.5% women, mean age 74.0±8.4 years) who underwent adenosine (with no additional exercise) stress myocardial perfusion single photon emission computed tomography (MPS) and were followed up for 2.0±0.8 years. Multivariable Cox proportional hazards analysis was used to assess the prognostic value of hemodynamic variables in predicting cardiac death (CD). Two hundred twenty-four CDs (6.5%) occurred during follow-up. By multivariable analysis, higher rest heart rate (HR) and to a lesser extent lower peak HR were markers of CD. When added to the multivariable model in place of peak and rest HR, the peak/rest HR ratio was an independent predictor of CD. Peak/rest HR ratio additionally risk-stratified patients within each MPS category. A significant interaction was found between gender and peak systolic blood pressure (SBP), in which there was an increased risk associated with a low peak SBP (<90 mm Hg at end of adenosine infusion) in men but not in women. Conclusions - Patients undergoing adenosine stress MPS with high rest HR and low peak/rest HR ratio have increased risk of CD, as do male patients with a low peak SBP. Assessment of the hemodynamic response to adenosine adds incremental prognostic value to MPS results and enhances identification of patients at risk for CD.