Wave intensity, an index of ventriculo-arterial interaction, increases in hypertensive subjects but decreases in normotensive subjects during the cold pressor test

PURPOSE: Cardiovascular reactivity to the cold pressor test (CPT) is considered to be a marker for apparent and potential hypertension. We aimed to elucidate the association between the changes in wave intensity (WI) during CPT and hypertension. METHODS: We recruited 85 volunteers, 33 of whom were hypertensive and 52 normotensive. Using ultrasonic equipment during CPT, we measured carotid arterial WI, which is defined in terms of blood pressure and velocity in the carotid artery. RESULTS: The peak WI (W(1)) increased during CPT in 70.6% of hypertensive individuals, but decreased in 72.6% of normotensive individuals. The chi-square (χ(2)) test showed that the association between the direction of change in W(1) (increase or decrease) and the blood pressure (hypertensive or normotensive) was very strong (P < 0.0001). CONCLUSION: Direction of change in W(1) during CPT is a clear marker to discriminate cardiovascular reactivity that does not vary depending on each investigator’s subjective point of view.