A delay in the decline of systolic blood pressure recovery after graded exercise tests has been suggested as an indicator of coronary artery disease (CAD). Recent studies have supported this idea but were limited because of small patient numbers and no systematic comparison of recovery and exercise blood pressures. McHam and colleagues studied the correlation between the rate of blood pressure decline during recovery with angiographic coronary disease and the increase of systolic blood pressure during exercise.
Adult patients who underwent symptom-limited graded exercise testing were enrolled in the study. Patients were included in the study if they had undergone a coronary angiography within 90 days of the exercise test, had no previous history of invasive coronary artery evaluation and had a history of congestive heart failure, cardiomyopathy, valvular heart disease, congenital heart disease or pre-excitation syndrome. Patients underwent a Bruce or modified Bruce exercise testing protocol, with blood pressure measurements throughout the test and at rest. Severe CAD was defined as: (1) stenosis diameter greater than 50 percent of the left main coronary artery; (2) three-vessel disease with greater than 70 percent stenosis in each major coronary artery system; or (3) two-vessel disease with greater than 70 percent diameter stenosis of the proximal left anterior descending coronary artery. A delayed decline in systolic blood pressure was measured as a ratio of systolic blood pressure measurements at three minutes of recovery to systolic blood pressure at one minute of recovery. A ratio greater than 1.0 was considered a delayed decline.
Of the 493 patients enrolled in the study, 102 had severe CAD according to the study's definition. Patients with severe CAD had higher resting systolic blood pressures, lower peak exercise systolic blood pressures and a slower decline of systolic blood pressure in the resting phase during the first three minutes. Patients with a slower decline in resting systolic blood pressure were more likely to have significant CAD.
The authors conclude that slow recovery of systolic blood pressure after graded exercise testing is an independent predictor of the presence of any and severe CAD. They also state that a blunted systolic blood pressure increase during exercise testing is suggestive of CAD. These two parameters can be used along with established parameters to determine the patients who need invasive cardiac evaluation exercise testing.