November 15, 1995Circulation
Intracoronary Low-Dose β-Irradiation Inhibits Neointima Formation After Coronary Artery Balloon Injury in the Swine Restenosis Model
Why the study?
Does intracoronary beta-irradiation reduce neointima formation in a swine model of coronary artery balloon injury?
Population
Normal domestic pigs undergoing balloon overstretch injury in the left anterior descending and left…
Comparison
Endovascular beta-radiation using a 2.5-cm… vs Control arteries
Design
Preclinical, random assignment into one of these arteries
Follow-up
14 days
Authors
Discussion
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Implication
Dose-dependent neointima inhibition by beta-irradiation in swine; leaves open translation to human restenosis prevention.
Key Points
- To determine whether intracoronary beta-irradiation using a strontium-90/yttrium-90 source inhibits neointimal hyperplasia after balloon overstretch injury and to characterize its dose-response relationship.
- Domestic pigs received balloon overstretch injury to the left anterior descending and left circumflex coronary arteries, with one artery randomly assigned to endovascular beta-irradiation using an afterloaded 90Sr/Y catheter.
- Vessels received one of four radiation doses (7, 14, 28, or 56 Gy delivered at 2 mm depth) or served as uninjured controls, with arterial histomorphometry and scanning electron microscopy conducted after 14 days.
- Irradiated vessels showed significantly reduced neointima formation, with intimal area-to-medial fracture length ratios decreasing inversely with dose: control (0.47), 7 Gy (0.34), 14 Gy (0.20), 28 Gy (0.08), and 56 Gy (0.02) (r = -0.78, P < 0.000001).
- Inhibition plateaued beyond 28 Gy, while scanning electron microscopy confirmed confluent endothelial-like cell coverage at 14 Gy with no significant necrosis or excess fibrosis in the media or adventitia.
Structured PICO
Does intracoronary beta-irradiation reduce neointima formation in a swine model of coronary artery balloon injury?
P
Population
Normal domestic pigs undergoing balloon overstretch injury in the left anterior descending and left circumflex coronary arteries (swine restenosis model)
I
Intervention
Endovascular beta-radiation using a 2.5-cm ribbon of encapsulated 90Strontium/90Yttrium (90Sr/Y) delivering 7, 14, 28, or 56 Gy to a depth of 2 mm
C
Comparator
Control arteries (balloon overstretch injury with no radiation)
O
Outcome
Neointima formation assessed by histomorphometric analysis (ratio of intimal area to medial fracture length) at 14 dayssurrogate
Intracoronary beta-irradiation with 90Sr/Y safely and dose-dependently inhibits neointima formation after balloon injury in a swine model.
Cite This Study
Waksman et al. (1995) studied this question.