[Differential indication for coronary stent implantation. Comparative study of acute cardial and vascular complications in relation to the indication].
BACKGROUND AND OBJECTIVE: Coronary stents are used nowadays not only for the reduction of restenosis and for treating acute vessel occlusions after PTCA but also after acute myocardial infarction. This study was undertaken to determine whether widening the indications has affected the incidence of acute complications and to compare acute cardiac and vascular complications. PATIENTS AND METHODS: The data on 197 consecutive patients (155 men, 42 women; mean age 62 +/- 9 [37-85] years) with coronary stents were analysed retrospectively, divided into 5 groups depending on the indications for the stent implantation: 1) acute or threatened vessel occlusion after elective PTCA ("bail-out"); 2) acute myocardial infarction (AMI); 3) unstable angina with threatened vessel occlusion; 4) suboptimal primary results (angiographically assessed) after PTCA; 5) elective stent implantation to prevent restenosis. Acute or subacute stent thrombosis, side-branch occlusion, intra- and transmural infarction, death and emergency aortocoronary bypass operation were classified as acute cardiac complications. Haemorrhage in the inguinal region requiring blood transfusion, false aneurysm and operative vascular reconstruction were classified as vascular complications. RESULTS: An intended stent implantation was impossible in 18 patients (primary success rate 91%). Independent of indication an acute or chronic stent stenosis occurred in three (1.6%) and seven (3.9%) patients, respectively. Side-branch occlusion was observed in 12 patients (6.7%), transmural infarction in nine (5.6%). No emergency bypass operation had to be performed. Comparing the different indication groups there was a significantly increased rate of "non-Q" infarctions in patients with unstable angina pectoris (P < 0.014). Among acute vascular complications (10 [5%] inguinal haemorrhages requiring transfusion and 5 [2.5%] operative vascular reconstructions), false aneurysm was significantly more common in patients with AMI (P < 0.014). Comparing emergency and elective stent implantations, side-branch occlusions were significantly more common in the former (12% vs. 0%; P < 0.08), as were also "non-Q" infarcts (10% vs. 0%; P < 0.002). CONCLUSION: Coronary stent implantation for these indications, including AMI, can be taken as firmly established. Stent thrombosis was not significantly increased after "bail out". Implantation in an acute ischaemic episode led to a significantly higher incidence of side-branch occlusion and "non-Q" infarction.