Data from experimental, clinical, and pathologic studies have suggested that the process ofrestenosis begins very early after coronary angioplasty. The present study was performed to determine prospectively the incidence of restenosis with use of the four National Heart, Lung, and Blood Institute and the 50% or greater diameter stenosis criteria, as well as a criterion based on a decrease of 0.72 mm or more in minimal luminal diameter. Patients were recatheterized at 30, 60, 90, or 120 days after successful percutaneous transluminal coronary angioplasty (PTCA). After PTCA all patients received 10 mg nifedipine three to six times a day and aspirin once a day until repeat angiography. Of 400 consecutive patients in whom PTCA was successful (<50% diameter stenosis), 342 underwent quantitative angiographic follow-up (86%) by use of an automated edge-detection technique. A wide variation in the incidence of restenosis was found dependent on the criterion applied. The incidence of restenosis proved to be progressive to at least the third month for all except NHLBI criterion II. At 4 months a further increase in the incidence of restenosis was observed when defined as a decrease of 0.72 mm or more in minimal luminal diameter, whereas the criteria based on percentage diameter stenosis showed a variable response. The lack of overlap between the different restenosis criteria applied affirms the arbitrary nature of angiographic definitions currently in use. Restenosis should be assessed by repeat angiography, and preferably ascertained according to the change in absolute quantitative measurements of the luminal diameter.

A computer-assisted technique has been developed to assess absolute coronary arterial dimensions from 35 mm cineangiograms.

L-Carnitine treatment initiated early after acute myocardial infarction and continued for 12 months can attenuate left ventricular dilation during the first year after an acute myocardial infarction, resulting in smaller left ventricular volumes at 3, 6 and 12 months after the emergent event.

To evaluate the efficacy of modern therapeutic procedures in the catheterization laboratory, the effects of vasoactive drugs, as well as the effects of short and long term interventions on the regression or progression of coronary artery disease, an objective and reproducible technique for the assessment of coronary artery dimensions was developed. This paper describes the methodology of such a computer-assisted analysis system, as well as the results from a validation study on the accuracy and precision. A region in a 35 mm cineframe encompassing a selected arterial segment is optically magnified and converted into video format by means of a specially constructed cinevideo converter and digitized for subsequent analysis by computer. Contours of the arterial segment are detected automatically on the basis of first and second derivative functions. Contour data are corrected for pincushion distortion; arterial dimensions are presented in mm, where the calibration factor is derived from a computer-processed segment of the contrast catheter. The accuracy and precision of the edge detection procedure as assessed from cinefilms of perspex models (%-D stenosis =/<70 percent) filled with contrast agent were -30 and 90 mum, respectively. The variablity of the analysis procedure by itself in terms of absolute arterial dimensions was less than 0.12 mm, and in terms of percentage arterial narrowing for coronary obstructions less than 2.74 percent. It is concluded that this system allows the measurement of coronary arterial dimensions in an objective and highly reproducible way.

For the prediction of CAD in patients presenting with acute chest pain and without ST-segment elevation, an admission MCG test was superior to an admission ECG, ECHO, and troponin-I. The results of the study, however, are applicable only to a highly selected population comprising patients in whom immediate coronary angiography can be performed based on their clinical course in the hospital.