We detected embolic particles liberated from plaque during percutaneous coronary intervention (PCI) as high-intensity transient signals (HITS) with a Doppler guidewire and studied their impact on coronary flow dynamics and the myocardium in patients with stable angina pectoris.Background:
These embolic particles during PCI may cause myocardial injury. However, this was difficult to confirm because it was impossible to detect embolic particles.Methods:
We performed balloon angioplasty followed by stenting in 31 patients while monitoring coronary flow velocity. After PCI, we measured average peak velocity at baseline and after infusion of adenosine 5′-triphosphate to calculate coronary flow velocity reserve (CFVR) and coronary resistance index (CRI). In patients with PCI to the left coronary artery (n= 21), we calculated relative CFVR as the ratio of CFVR in the target vessel to that in the reference vessel. We measured cardiac troponin T (cTnT) the day after PCI.Results:
HITS were detected in 27 (87%) of 31 patients and the majority were observed after stenting. The total number of HITS was correlated with CRI (r= 0.36,P= 0.049) or relative CFVR (r= 0.65,P= 0.0036) but not with CFVR (r= 0.048,P= 0.82). Thirteen patients showed elevated cTnT (range, 0.05–0.31 ng/ml) and the total number of HITS was greater in those with elevated cTnT than in those without elevated cTnT (24 ± 9 vs. 10 ± 7,P= 0.0007).Conclusions:
Embolic particles are frequently observed during PCI to stable plaque and the majority are liberated after stenting. There appears to be a quantitative relationship between amounts of HITS and coronary microvessel dysfunction and minor myocardial injury.