High-dose intravascular beta-radiation after de novo stent implantation induces coronary artery spasm.
BACKGROUND
Intracoronary brachytherapy is effective in preventing restenosis after coronary interventions. However, in vitro and animal studies have shown that irradiation produces immediate and sustained endothelial dysfunction. This study assesses the clinical relevance of impaired vasomotoric function induced by brachytherapy.


RESULTS
We analyzed the occurrence of postradiation coronary artery spasms in 1 animal study and 2 clinical trials investigating the effects of high-dose intracoronary beta-radiation after de novo coronary artery stenting. Irradiated segments (IRSs) proximal and distal to the stent were studied by quantitative coronary angiography after stenting, after radiation, and at the end of the procedure. There was an 67% overall incidence of coronary artery spasm in the IRSs immediately after beta-radiation compared with 9% after sham treatment (P<0.001). Whereas in most cases this phenomenon was only minor or moderate, in 12 cases, 4 (22%) animals and 8 (28%) patients, severe coronary spasm (>90% diameter stenosis) with significant ECG-changes or hemodynamic instability was observed. Relief of spasms was protracted (mean time until complete relief of spasm 423+/-122 seconds) and required repetitive intracoronary administration of nitroglycerin (mean dose: 1.2+/-0.6 mg).


CONCLUSIONS
Vasoconstriction is a frequent reaction of coronary arteries after high-dose intracoronary beta-radiation, necessitating repetitive administration of vasodilators.
Scheinert
D
D
Department of Cardiology, University of Erlangen-Nuremberg, Germany. dierk.scheinert@gmx.de
Strnad
V
V
Müller
R
R
Burckhard
R
R
Ropers
S
S
Sauer
R
R
Daniel
W G
WG
Bonan
R
R
Ludwig
J
J
D000818:Animals; D001610:Beta Particles / Q000009:adverse effects*; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects*; D001918:Brachytherapy / Q000009:adverse effects*; D002404:Catheterization / Q000009:adverse effects; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000601:surgery; D003329:Coronary Vasospasm / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology*; D004195:Disease Models, Animal; D004307:Dose-Response Relationship, Radiation; D004562:Electrocardiography; D006801:Humans; D015994:Incidence; D007269:Injections, Intra-Arterial; D005996:Nitroglycerin / Q000008:administration & dosage; D010865:Pilot Projects; D015607:Stents; D013552:Swine; D017539:Tunica Intima / Q000293:injuries / Q000528:radiation effects; D018084:Ultrasonography, Interventional; D014665:Vasodilator Agents / Q000008:administration & dosage
D014665:Vasodilator Agents; D005996:Nitroglycerin