ACUTE MYOCARDIAL-INFARCTION DUE TO MUSCULAR BRIDGING OF THE LEFT ANTERIOR DESCENDING ARTERY - CLINICAL COURSE COMPLICATED BY CORONARY-ARTERY PERFORATION AFTER STENT IMPLANTATION - CASE-REPORT AND REVIEW OF THELITERATURE

A 47-year-old male patient was admitted to our hospital with acute ant erior myocardial infarction. Immediate coronary angiography was carrie d out, which showed proximal occlusion of the left anterior descending artery (LAD). After mechanical recanalization, a reduction in vessel caliber at the site of occlusion was visible, and balloon angioplasty with consecutive stent implantation because of vessel wall dissection was performed. After the procedure, diameter reduction of the entire v essel segment distal to the stent and muscular bridging with subtotal systolic obliteration of the LAD and one diagonal branch were demonstr ated. Diastolic coronary flow did not appear to be limited (TIMI 3). D ipyridamole-thallium cardiac imaging revealed an incomplete perfusion defect of the anteroseptal region and a reversible perfusion reduction of the anterolateral region. For definitive treatment, we decided to implant a 3.0 mm-stent at the site of muscular bridging. Although ball oon sizing was adapted to the diameter of the proximal reference segme nt. measured by quantitative coronary angiography, coronary perforatio n into the right ventricular outflow tract due to balloon oversizing i n the distal dilation segment occurred. The patient remained asymptoma tic at rest as well as under exercise testing, and hemodynamics remain ed stable. Coronary re-angiography after 1 week demonstrated a persist ent fistula with complete opacification of the LAD and normal coronary flow (TIMI 3). Within the following 3 months, the coronary fistula cl osed spontaneously. Conclusions: Muscular bridging is a ran cause of a cute myocardial infarction. Balloon angioplasty and stent implantation in the bridged segment may be complicated by coronary artery perforat ion due to balloon oversizing. Risks and benefits of this therapeutic option, therefore, have to be critically evaluated, and careful select ion of balloon size using measurements of proximal and distal referenc e diameter assessed hv intravascular ultrasound is recommended. Corona ry artery perforation into the myocardium with subsequent development of a fistula may be treated conservatively as long as the patient rema ins asymptomatic. The frequency of spontaneous closure of the fistula is high.