FACTORS OF INFLUENCE ON RESTENOSIS-RATE A FTER IMPLANTATION OF PALMAZ-SCHATZ-STENTS AND AVE-MICRO-STENTS

Late results of interventional procedures utilizing coronary stents ar e lamely determined by the rate of restenosis. So far few data are ava ilable addressing the effect of stent design, implantation pressure an d morphologic factors on this crucial variable. Therefore we analyzed the coronary angiogramms obtained in 259 patients before, immediately after and at 3 to 6 months following stent implantation for obstructiv e coronary disease. A total of 196 AVE-Micro-Stents and 142 Palmaz-Sch atz-Stents were implanted into 307 stenoses. in 126 stenoses there wer e implanted only Palmaz-Schatz-Stents, in 170 only AVE-Micro-Stents an d in 11 stenoses there were implanted Palmaz-Schatz-as well as Micro-S tents. Restenosis was defined as an over 50 % stenosis at follow up, N o significant difference was detected with regard to global restenosis rate at an average of 4 months following implantation (Palmaz-Schatz 33 %, Micro;Stent 27 %). If results were analyzed according to implant ation pressure however, there was a significantly lower restenosis rat e for AVE-Micro-Stents implanted with > 10 atm (17 %) as compared to l ess than or equal to 10 atm (35 %, p < 0.02) and as compared to Palmaz -Schatz-Stents (34 %. p < 0.02), which were also implanted with high p ressure over 10 atm. In addition to implantation pressure, vessel segm ent and morphology of stenosis proved to be important determinants of late results. In this series of patients the AVE-Micro-Stent compared favourably to the Palmaz-Schatz-Stent not only with respect to a signi ficantly lower restenosis rate, when inplanted with pressures > 10 atm , but also with regard to its superior flexibility and handling charac teristics.