PubMed · 7253170
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
1981-08-28. Indications and contraindications for exercise testing.. https://pubmed.ncbi.nlm.nih.gov/7253170/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
To determine the reliability of geometric (edge-detection) quantitative coronary angiographic analysis (QCA) of restenosis within a new Cordis tantalum stent, QCA and intracoronary ultrasound (ICUS) measurements were compared in both an experimental restenosis model and in the clinical follow-up of patients. In the experimental series, Plexiglas phantom vessels with concentric stenosis channels ranging from 0.75 to 3.0 mm in diameter and with a reference diameter of 3.0 mm were imaged both before and after their insertion in tantalum stents. In the clinical series, the agreement of QCA and ICUS measurements were studied in 23 patients who had undergone coronary implantation of the new tantalum stent and in 23 patients who had undergone balloon angioplasty 6 months previously. The reliability of QCA declined in the presence of the radiopaque stent (accuracy of QCA decreased from -0.07 to -0.12 mm), whereas the reliability of lumen measurements by ICUS was independent of the presence of the radiopaque stent (-0.12 and -0.13 mm). Without the stent, the average minimal luminal diameter (MLD) obtained by QCA of the 1.00 mm Plexiglas vessel was 1.00 +/- 0.01 mm, and the 3.00 mm reference vessel diameter was 2.81 +/- 0.05 mm, providing a 64 +/- 1% diameter stenosis. After introduction of the stent, the average MLD and reference vessel diameter were 0.99 +/- 0.06 and 3.36 +/- 0.17 mm, respectively, providing a diameter stenosis of 71 +/- 2%. ICUS measurements (2.77 mm) of the reference vessel diameter (3.00 mm) were unaffected by the presence of the stent.(ABSTRACT TRUNCATED AT 250 WORDS)
BACKGROUND: An aggressive and potentially fatal form of coronary artery disease may develop after cardiac transplantation. We studied the role of vascular tissue plasminogen activator (t-PA), the primary mediator of fibrinolysis, in the development of this problem. METHODS: We studied 78 consecutive recipients of cardiac allografts over a five-year period, and we collected follow-up data over a mean (+/- SE) of 32.5 +/- 2.0 months. The patients were studied with ventricular function tests, serial endomyocardial biopsies (16.6 +/- 0.5 per patient), and annual coronary angiography. Measurements of t-PA and its inhibitor were performed immunocytochemically on unfixed cryostat sections of endomyocardial-biopsy specimens with the use of monoclonal antibodies to t-PA and its inhibitor. RESULTS: In biopsy specimens obtained during the first three months of follow-up, 38 allografts had a normal distribution of t-PA in arteriolar smooth-muscle cells, whereas in 40 allografts there was depletion of t-PA that persisted in subsequent follow-up. Coronary artery disease developed during follow-up in 31 of 40 allografts (78 percent) with depletion of t-PA, but the disease developed in only 9 of the 38 allografts (24 percent) with normal t-PA levels (P < 0.001). Allografts with depletion of t-PA also had the t-PA inhibitor and were at greater risk for earlier and more severe disease than were allografts with normal arteriolar t-PA levels. Twelve patients whose allografts were depleted of t-PA either received a second transplant or died, whereas only one of the patients whose allografts had persistently normal t-PA levels died (P < 0.001). CONCLUSIONS: These findings reveal an association between the depletion of t-PA from arteriolar smooth-muscle cells and the subsequent development of coronary artery disease and decreased graft survival. Although we cannot be certain about a cause-and-effect relation, our data suggest a possible role for deficient fibrinolysis in the development of coronary artery disease in transplanted human hearts.
Explore the source record for details and available documents.