Background: Percutaneous coronary intervention (PCI) is known to induce atherosclerotic plaque rupture, which may affect resting distal microvascular perfusion either through distal microvascular spasm or through embolization. We evaluated the effect of PCI on resting microvascular flow.
Methods: We performed cardiovascular magnetic resonance imaging to assess left ventricular systolic function and microvascular perfusion in 15 patients with stable coronary artery disease before and within 24 hours after PCI and in 10 control subjects without obstructive coronary artery disease on a clinical 1.5-T CMR scanner. Microvascular perfusion was evaluated at rest after injecting a bolus of gadolinium-diethylenetriamine pentaacetic acid (0.1 mmol/kg) by calculating the time to 50% maximum myocardial enhancement (T50% max), as well as the relative upslope, of the myocardial signal intensity curve. Regional perfusion and systolic thickening were evaluated using a 16-segment left ventricular model with the slice locations matched anatomically pre-PCI and post-PCI. The relative contrast delay in the region of myocardium subtended by the PCI artery was calculated by subtracting the T50% max of a remote region from the PCI region.
Results: In subjects with coronary artery disease, PCI resulted in a regional contrast delay (mean delay 0.6 +/- 0.2 seconds post-PCI vs 0.0 +/- 0.2 seconds pre-PCI, P < .05) and a reduction in the relative upslope (8.6 +/- 0.5 post-PCI vs 10.1 +/- 0.7 pre-PCI, P = .02), consistent with reduced microvascular perfusion. This was unaccompanied by any change in regional systolic thickening (54% +/- 7% pre-PCI vs 53% +/- 5% post-PCI, P = NS).
Conclusions: The data show PCI-induced impairment of resting microvascular perfusion in the area of myocardium subtended by the treated artery after PCI, a likely consequence of iatrogenic atherosclerotic plaque rupture.