Coronary artery disease and depression: Patients with more depressive symptoms have lower cardiovascular reactivity during laboratory-induced mental stress

Objective: To investigate the relationship between symptoms of depression and cardiovascular reactivity during mental stress in patients with coronary artery disease (CAD). Depressive symptoms are common in patients with CAD and are related to an increased risk of cardiac events and death. Some researchers have proposed that negative outcomes in depressed patients with CAD may be related to exaggerated cardiovascular reactivity and psychological stress. However, the data are unclear. Methods: Patients with CAD (n = 128; mean age = 64 years) were recruited for this study. Participants underwent psychological stress testing and 2-day (stress/rest) radionuclide imaging. The Beck Depression Inventory (BDI) results were collected at baseline. Cardiac function data were also gathered and stress data were compared with baseline findings. Results: The change in systolic blood pressure (SBP) from rest to stress was 47 +/- 18 (mean +/- standard deviation) mm Hg, diastolic blood pressure (DBP) = 30 +/- 11 mm Hg, double product difference (DP) = 5887 +/- 3095, and heart rate (HR) = 20 +/- 13 beats/minute (p < .001 for all). The BDI score was 8.7 +/- 5.6. The BDI score was negatively correlated with all hemodynamic variables, although only significant with stress SBP and DP, and HR and DP changes. BDI scores also predicted changes in HR and DP. HR remained significant in regression analyses controlling for other sample characteristics. Conclusions: This study showed a negative relationship between depressive symptoms and cardiovascular reactivity to mental stress. In contrast to the mechanism proposed by earlier researchers, this study suggests that decreased cardiovascular reactivity occurs with increased depressive symptomology. The mechanism by which this effect occurs and its clinical significance are still unknown.