Abstract 12229: Myocardial Ischemia During Mental Stress: Role of Coronary Artery Disease Burden and Vasomotion
Background: Myocardial ischemia induced by mental stress (MSI) portends a worse prognosis in patients with CAD, irrespective of traditional risk factors or physical stress ischemia (PSI). Yet, the mechanisms underlying MSI and whether they differ from those underlying PSI remain unclear.
Hypothesis: Compared to PSI that is largely secondary to epicardial atherosclerotic burden, MSI is primarily due to vasomotor changes.
Methods: Patients (n=384) with angiographically documented CAD underwent 99m-Tc-sestamibi myocardial perfusion imaging at rest and following both mental and physical stress testing, performed on separate days. The angiographic severity and extent of CAD were quantified using the Gensini and Sullivan coronary scoring systems. Peripheral arterial tonometry (PAT) was used to assess the digital microvascular tone during mental stress as a ratio of pulse wave amplitude during speech compared to baseline with a ratio≤1 signifying a vasoconstrictor response.
Results: MSI occurred in 52 (14%) patients and PSI in 125 (33%). All hemodynamic measures increased in response to mental stress (P≤0.001), and the increase was similar in those with or without MSI. CAD severity and extent scores were similar in those with and without MSI (P>0.7 for all), whereas they were greater in those with compared to those without PSI (p≤0.001 for all). Notably, in those with PSI, the occurrence of MSI was not associated with more severe CAD (Figure). The PAT ratio was lower in those with compared to those without MSI (0.6±0.4 vs. 0.8±0.5, P=0.009). In a multivariate analysis, a lower PAT ratio during mental stress was the only independent predictor of MSI (P=0.009), whereas angiographic severity and extent of CAD independently predicted PSI.
Conclusions: The degree of digital microvascular constriction, and not the angiographic burden of CAD, is associated with MSI. Varying etiologies of MSI compared to PSI may require different therapeutic interventions that require further study.
- © 2013 by American Heart Association, Inc.