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.