Influence of increased heart rate and aortic pressure on resting indices of functional coronary stenosis severity.

Accordingly, BMR decreased by 27% (p < 0.01) and velocity increased by 36% (p < 0.05), while Pd/Pa decreased by 0.05 ± 0.02 (p < 0.05) and BSR remained similar to control. Raising Pa to 121 ± 3 mmHg (PE) with concomitant reflex bradycardia increased BMR by 26% (p < 0.001) at essentially unchanged RPP and velocity. Consequently, BSR and Pd/Pa were only marginally affected. During PE + sHR, velocity increased by 21% (p < 0.01) attributable to a 46% higher RPP (p < 0.001). However, BMR, BSR, and Pd/Pa remained statistically unaffected. Nonetheless, the interventions tended to increase functional stenosis severity, causing Pd/Pa and BSR of borderline lesions to cross the diagnostic threshold. In conclusion, coronary microvascular adaptation to physiological conditions affecting metabolic demand at rest influences intracoronary hemodynamics, which may lead to altered basal stenosis indices used for clinical decision-making.