Supine bicycle exercise during cardiac catheterization was safe and effective in patients with severe aortic stenosis, according to recent data published in the Journal of the American College of Cardiology.

The data suggest that invasive coronary physiological evaluation can be safely performed during exercise in this patient population.

Matthew Lumley, BSc, of the British Heart Foundation Centre of Excellence and National Institute for Healthat King’s College, London, UK, and colleagues sought to describe the coronary physiological changes during exercise and hyperemia in 22 patients with severe aortic stenosis compared with 38 control patients with healthy hearts.


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Researchers recorded simultaneous intracoronary pressure and flow velocity readings from the unobstructed arteries at rest, during supine bicycle exercise, and during hyperemia. Patients also underwent stress echocardiography to estimate myocardial work. Researchers used wave intensity analysis to quantify waves that affect coronary blood flow.

Catheterization was performed via the right radial artery with standard coronary catheters, and a specially adapted supine cycle ergometer was attached to the catheter laboratory table.

Data showed a greater myocardial workload in patients with aortic stenosis compared with healthy controls at rest (12 721 vs 9707 mm Hg/min-1; P=.003) and during peak exercise (27 467 vs 20 841 mm Hg/min-1; P=.02), but coronary blood flow was similar in both groups. Cardiac output in the 13 patients with aortic stenosis who underwent a stress echocardiography was 5.4 ± 1.6 l/min-1 at rest and increased to 9.3 ± 2.5 l/min-1 during peak exercise (P=.001).

In addition, researchers found that hyperemic coronary blood flow was less among patients with severe aortic stenosis compared with controls (2170 vs 2716 cm/min-1; P=.05). Patients with severe aortic stenosis also had greater diastolic time fraction, and minimum microvascular resistance was similar between both groups.

In the healthy heart, the efficiency of perfusion improved with exercise and hyperemia. However, in patients with severe aortic stenosis, perfusion efficiency decreased “due to augmentation of early systolic deceleration and an attenuated rise in systolic acceleration waves.”

“We resolved the debate regarding the cause of ischemia in AS with normal coronary arteries by showing that AS [aortic stenosis] patients have a higher workload, normal minimum MR [microvascular resistance], and shorter diastolic perfusion time compared with controls, thereby demonstrating that microvascular disease is not a factor in AS,” the authors wrote.

“Moreover, the data suggested that a greater increase in early systolic deceleration (associated with isovolumetric systolic myocardial compression) was responsible for reduced CFR [coronary flow reserve] in AS vs controls.”

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Reference

Lumley M, Williams R, Asrress KN, et al. Coronary physiology during exercise and vasodilation in the healthy heart and in severe aortic stenosis. J Am Coll Cardiol. 2016;68(7): 688-697. doi: 10.1016/j.jacc.2016.05.071.