Impact of PCI on Exercise Hemodynamics in Stable CAD Patients
Study Questions:
What is the impact of percutaneous coronary intervention (PCI) on exercise responses in the coronary circulation, the microcirculation, and systemic hemodynamics in patients with stable coronary artery disease (CAD)?
Methods:
A total of 21 patients with stable CAD and single-vessel coronary stenosis underwent cardiac catheterization. Patients continued all usual medications and were loaded with dual antiplatelet agents as per routine practice of the recruiting center. Pre-PCI, patients exercised on a supine ergometer until rate-limiting angina or exhaustion. Simultaneous trans-stenotic coronary pressure-flow measurements were made throughout exercise. Post-PCI, this process was repeated. Physiological parameters, rate-limiting symptoms, and exercise performance were compared between pre-PCI and post-PCI exercise cycles.
Results:
Mean age was 60.3 years, 91% were male, and 95% had Canadian Cardiovascular Society class II-III angina; 76% were on beta-blockers and angiotensin-converting enzyme inhibitors/angiotensin-receptor blockers (ACEi/ARB), 29% on nitrates, and 38% on calcium channel blockers. Target vessel was left anterior descending artery in 11 and right coronary artery or circumflex artery in 10. Mean stenosis diameter by quantitative coronary angiography was 75.7 ± 10.3%. PCI reduced ischemia as documented by fractional flow reserve value (pre-PCI 0.59 ± 0.18 to post-PCI 0.91 ± 0.07) and coronary flow reserve value (pre-PCI 1.7 ± 0.7 to post-PCI 3.1 ± 1.0; p < 0.001 for all). PCI increased peak-exercise average peak coronary flow velocity (p < 0.0001), coronary perfusion pressure (distal coronary pressure; p < 0.0001), systolic blood pressure (p = 0.01), accelerating wave energy (p < 0.001), and myocardial workload (rate-pressure product; p < 0.01). These changes observed immediately following PCI resulted from the abolition of stenosis resistance (p < 0.0001). PCI was also associated with an immediate improvement in exercise time (± 67 seconds; 95% confidence interval, 31-102 seconds; p < 0.0001) and an 81% reduction in rate-limiting angina symptoms post-PCI (p < 0.001).
Conclusions:
In patients with stable CAD and severe single-vessel stenosis, objective physiological responses to exercise immediately normalize following PCI. This is seen in the coronary circulation, the microcirculation, and systemic hemodynamics.
Perspective:
This interesting elegant study has several limitations, each of which could influence the results. The nitrate, ACEi/ARB, and beta-blocker therapies were given on the morning of the study, and intracoronary nitroglycerin and intravenous adenosine were administered prior to physiologic measurements, each of which influence epicardial and microcirculatory flow. The authors concluded that in contrast to the traditional advice that patients should only resume exercise in a delayed and graduated fashion following PCI, this study demonstrates the safety of performing maximal physical exercise immediately after coronary stenting. Among the several reasons for not embarking on regular intense exercise very early is that in clinical practice, it is not uncommon that the electrocardiographic evidence for ischemia may persist and is thought to be abnormal vasodilator reserve of the epicardial and microcirculation, and the potential of early stent thrombosis.
Clinical Topics: Cardiac Surgery, Cardiovascular Care Team, Diabetes and Cardiometabolic Disease, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Prevention, Atherosclerotic Disease (CAD/PAD), Aortic Surgery, Cardiac Surgery and Arrhythmias, Cardiac Surgery and SIHD, Interventions and Coronary Artery Disease, Interventions and Imaging, Angiography, Nuclear Imaging, Exercise
Keywords: Adenosine, Angina Pectoris, Angiotensin-Converting Enzyme Inhibitors, Blood Pressure, Calcium Channel Blockers, Cardiac Catheterization, Coronary Angiography, Coronary Artery Disease, Coronary Circulation, Coronary Stenosis, Electrocardiography, Exercise, Fractional Flow Reserve, Myocardial, Ischemia, Microcirculation, Myocardial Revascularization, Nitrates, Nitroglycerin, Percutaneous Coronary Intervention, Platelet Aggregation Inhibitors, Primary Prevention, Stents, Thrombosis, Vasodilator Agents, Workload
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