Background: The main long-term complication of percutaneous transluminal coronary angioplasty (PTCA) is restenosis that occurs in 30-50 percent of all primary successful cases. The purpose of this study was to evaluate the predictive value of changes in plasminogen activator inhibitor-1 (PAI-1) activity and of thallium dipyridamole perfusion imaging performed 3 months after successful angioplasty. All patients were asymptomatic at evaluation. The results of these two noninvasive tests were compared with the angiographic outcome after 6 months.
Method and patients: Twenty-five patients were included in this prospective study. All patients had single vessel disease, successful angioplasty and were free of clinical symptoms 3 months after angioplasty that would suggest late restenosis. In 12/25 patients (48%) angiographic restenosis (percent diameter stenosis >50%) was determined by follow-up angiography 6 months after angioplasty. PAI-1 plasma activity was determined by a functional titration assay and increase or decrease of PAI-1 plasma activity was evaluated between values obtained before and 3 months after angioplasty. In 7/25 (28%) patients PAI-1 plasma activity increased to more than 90% of pre-angioplasty values. This increase correlated with angiographic restenosis evaluated 6 months after angioplasty (sensitivity 42%, specificity 85%, positive predictive value 71%, and negative predictive value 61%). T1-201-perfusion imaging was performed 3 months after angioplasty. This test was indicative for subsequent restenosis in 5/25 patients (sensitivity 33%, specificity 100%, positive predictive value 62%, and negative predictive value 100%). In 10/25 (40%) patients at least one of the two non-invasive tests performed 3 months after angioplasty predicted angiographic restenosis at 6 months: the combined use of PAI-1 and T1-201-perfusion imaging resulted in increased sensitivity (67%) and high specificity (85%).
Conclusion: The results of this study indicate that an increase of PAI-1 plasma activity may improve the predictive value for restenosis of T1-201-scintigraphy performed 3 months after angioplasty even in asymptomatic patients.