PCI May Improve Blood Flow During Exercise for Patients With Stable Coronary Artery Disease

August 21, 2018—A small study from Christopher M. Cook, MD, et al found that objective physiological responses to exercise normalized immediately after percutaneous coronary intervention (PCI) in patients with stable coronary artery disease (SCD) and severe single-vessel stenosis. The study was published in Journal of the American College of Cardiology (JACC; 2018;72:970–983).

The study was undertaken to address challenges to the therapeutic benefits of PCI for patients with SCD. Researchers set out to examine the impact of PCI on exercise responses in the coronary circulation, the microcirculation, and systemic hemodynamics in patients with SCD.

To assess the impact of PCI, researchers performed cardiac catheterization on 21 patients (mean age, 60.3 ± 8.4 years) with SCD and single-vessel coronary stenosis. Before PCI, patients were evaluated on a supine ergometer until rate-limiting angina or exhaustion while researchers collected transstenotic coronary pressure-flow measurements. This test was then repeated after PCI. Pre- and post-PCI physiological parameters, rate-limiting symptoms, and exercise performance were compared.

According to researchers in JACC, PCI reduced ischemia as documented by fractional flow reserve value (pre-PCI 0.59 ± 0.18 to post-PCI 0.91 ± 0.07), instantaneous wave-free ratio value (pre-PCI 0.61 ± 0.27 to post-PCI 0.96 ± 0.05), and coronary flow reserve value (pre-PCI 1.7 ± 0.7 to post-PCI 3.1 ± 1.0; P < .001 for all).

Additional findings reported include increased peak-exercise average peak coronary flow velocity (P < .0001), coronary perfusion pressure (distal coronary pressure; P < .0001), systolic blood pressure (P = .01), accelerating wave energy (P < .001), and myocardial workload (rate-pressure product; P < .01) after PCI.

Investigators reported that these changes observed immediately after PCI resulted from the abolition of stenosis resistance (P < .0001). PCI was also associated with an immediate improvement in exercise time (+67 seconds; 95% confidence interval: 31 to 102 seconds; P < .0001) and a reduction in rate-limiting angina symptoms (81% reduction in rate-limiting angina symptoms post-PCI; P < .001).

Improved physiological responses to exercise in patients with SCD and severe single-vessel stenosis after PCI can be seen through improvements in coronary circulation, the microcirculation, and systemic hemodynamics outcomes, concluded the investigators in JACC.