Background and Objectives：Some reports suggested that microvascular dysfunction is important factor for the recovery of myocardial function in obstructive coronary artery disease. However, the assessment of microvascular dysfunction is relatively difficult, so its clinical application is limited. Recently, TIMI frame count(TFC) is regarded as a simple, reliable method to evaluate the microvascular function. So we evaluated the microvascular function by TFC immediately after coronary intervention and compared it with the left ventricular systolic function after 1 year.
Subjects and Methods：We included 68 patients of obstructive coronary artery disease who underwent coronary intervention. Just after intervention, TFC was calculated by standard method in each left and right coronary artery. Left ventricular systolic function was assessed by echocardiographic parameters such as left ventricular diastolic dimension(LVEDd), ejection fraction(EF), and echocardiographic score(ES). After 1 year of intervention, we repeated follow-up coronary angiography and echocardiography as a same method. We statistically defined slow coronary flow(SCF) as if TFC was more than 20.
Results：Nine patients were in SCF group and 56 patients were in normal coronary flow(NCF) group. There was also no difference in baseline cardiovascular characteristics and angiographic findings. Just after intervention, the SCF group showed higher LVEDd(54±9mm), ES(1.5±0.4) and lower EF(47.6±14.9%) compared to those of NCF group (50±6mm, 1.3±0.3, 56.6±15.2%, respectively), but they were not statistically significant. One year after intervention, LVEDd of SCF group (61±12mm) was significantly higher than that of NCF group(50±7mm, p<0.01). There was also significant difference of ES between groups(SCF;1.64±0.54, NCF;1.25±0.35. p<0.05). The SCF group showed lower EF(50.8±19.2%) compared to that of NCF group(62.2±13.8%), but it was not statistically significant.
Conclusion：Increased TFC is a important poor prognostic factor of myocardial systolic function after 1 year of coronary intervention. Microvascular dysfunction after intervention could influence the recovery of myocardium of obstructive coronary artery disease.
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