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J Vasc Interv Radiol. 1994 May-Jun;5(3):425-32.

Repeat dilation of Palmaz stents in pulmonary arteries: study of safety and effectiveness in a growing animal model.

Author information

1
Department of Interventional Radiology/Cardiovascular Diagnostic Laboratory, Johns Hopkins Medical Institutions, Baltimore, Md.

Abstract

PURPOSE:

This study assessed the technical feasibility and safety of repeat dilation of Palmaz stents in growing pulmonary arteries.

MATERIALS AND METHODS:

Palmaz stents (1.2 cm long) were placed percutaneously into the pulmonary arteries of 20 newborn lambs. After 4 months, pulmonary arteriography was performed. Where vessel growth in excess of stent diameter had created a stenosis (> 15%), stents were dilated again percutaneously. Six months later, pulmonary arteriography was performed, before the animal was killed and histologic examination performed.

RESULTS:

Twenty-four pulmonary artery stent placements were attempted; 23 were successful. One stent placement was unsuccessful owing to stent displacement from the balloon. Acute complications included branch pulmonary artery occlusion (n = 3) and stent displacement from the delivery balloon (n = 2). At 4 months, the desired degree of stenosis (> 15%) was achieved in 11 animals. The average stenosis was 35% (standard deviation, 16%; range, 17%-66%). The mean predilation stent diameter was 6 mm +/- 1.1 (range, 4-8 mm), and the final diameter of 8 mm +/- 1.4 (range, 6-10 mm), represented a 35% mean increase (P < .001). Complications included stent (n = 1) and branch vessel (n = 1) thrombosis. At 6-month follow-up, all stents were patent. Areas of previously noted branch thrombosis were fully recanalized in all cases. At histologic inspection, only a thin layer of neointima was found on the stents.

CONCLUSION:

Repeat dilation of Palmaz stents may be safely performed in growing pulmonary arteries in an animal model. Neointimal hyperplasia is minimal in pulmonary artery stents.

PMID:
8054740
DOI:
10.1016/s1051-0443(94)71520-7
[Indexed for MEDLINE]

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