Volumetric assessment of neointimal hyperplasia in iliac arteries after metal stent implantation

OBJETIVO: Quantificar a hiperplasia neointimal em artérias ilíacas após stent, correlacionando fatores clínicos, arteriais e materiais dos stents. MATERIAIS E MÉTODOS: De junho de 2003 a agosto de 2005, 60 pacientes realizaram angioplastia transluminal percutânea e stent. Desses, 30 foram reestudados com ultrassonografia intravascular. Os dados foram analisados no laboratório de análise quantitativa. RESULTA-DOS: Dezesseis pacientes eram do sexo masculino (53,3%) e 14 (46,7%), do sexo feminino. A média de idade foi de 60,3 anos. Apresentaram hipertensão arterial 22 pacientes (73,3%), tabagismo, 18 (62,1%), hiperlipidemia, 20 (66,7%), e diabetes, 9 (30%). Foram implantados 20 stents de nitinol (66,7%) e 10 de aço inoxidável (33,3%). Quatro pacientes eram TASC A (13,3%), 15 eram TASC B (50%) e 11, TASC C (36,7%). O volume da hiperplasia variou de 49,02 mm³ a 112,87 mm³ (média de 80,33 mm³). O percentual de obstrução intra-stent variou de 18% a 47% (média de 27,4%). Os resultados clínicos obtidos com stent se mantiveram até o reestudo. CONCLUSÃO: A hiperplasia neointimal sempre ocorre após a angioplastia transluminal percutânea e stent, porém os percentuais de obstrução não foram superiores a 50% em nenhum caso. Não houve diferença estatisticamente significante dos percentuais de obstrução intra-stent quanto aos materiais dos stents, aos fatores clínicos e aos fatores arteriais. OBJECTIVE: To quantify neointimal hyperplasia in iliac arteries after stent implantation, correlating clinical, arterial factors and stent material. MATERIALS AND METHODS: In the period from June/2003 to August/ 2005, 60 patients were submitted to percutaneous transluminal angioplasty and stenting. Among these patients, 30 were followed-up with intravascular ultrasonography. Data were analyzed in a laboratory of quantitative analysis by means of a specific software. RESULTS: Sixteen (53.3%) patients were men, and 14 (46.7%), women, and the mean age was 60.3 years. Arterial hypertension was observed in 22 patients (73.3%), smoking in 18 (62.1%), hyperlipidemia in 20 (66.7%), and diabetes in 9 (30%). A total of 20 nitinol stents (66.7%) and 10 stainless steel stents (33.3%) were implanted. Four patients were classified as TASC A (13.3%), 15 TASC B (50%) and 11 TASC C (36.7%). The neointimal hyperplasia volume ranged from 49.02 mm³ to 112.87 mm³ (mean, 80.33 mm³). The rate of intrastent obstruction ranged from 18% to 47% (mean, 27.4%). The clinical outcomes achieved with stenting were sustained through the follow-up. CONCLUSION: Neointimal hyperplasia is a common finding after percutaneous transluminal angioplasty and stenting, but in the present study the stenosis rate was never higher than 50%. There was no statistically significant difference in intrastent stenosis rates in relation to stents materials, clinical and arterial risk factors.