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1.
Am Heart J ; 142(6): 970-4, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11717599

RESUMO

OBJECTIVES: Serial intravascular ultrasonographic (IVUS) studies have shown that in-stent restenosis is the result of intimal hyperplasia (IH). However, routine preintervention IVUS imaging has suggested that many restenotic stents were inadequately deployed. The purpose of this IVUS study was to determine the incidence of mechanical problems contributing to in-stent restenosis (ISR). METHODS: Between April 1994 and June 2000, 1090 patients with ISR were treated at the Washington Hospital Center. All underwent preintervention IVUS imaging. IVUS measurements included proximal and distal reference lumen areas and diameters; stent, minimum lumen, and IH (stent minus lumen) areas; and IH burden (IH/stent area). RESULTS: In 49 ISR lesions (4.5%), there were morphologic findings that contributed to the restenosis. These were termed mechanical complications. Examples include (1) missing the lesion (eg, an aorto-ostial stenosis), (2) stent "crush," and (3) having the stent stripped off the balloon during the implantation procedure. Excluding mechanical complications, stent underexpansion was common. In 20% of the ISR cases the stents had a cross-sectional area (CSA) at the site of the lesion <80% of the average reference lumen area. Twenty percent of lesions had a minimum stent area <5.0 mm(2) and an additional 18% had a minimum stent area of 5.0 to 6.0 mm(2). Twenty-four percent of lesions had an IH burden <60%. CONCLUSION: Mechanical problems related to stent deployment procedures contribute to a significant minority of ISR lesions (approximately 25%).


Assuntos
Estenose Coronária/diagnóstico por imagem , Estenose Coronária/terapia , Stents/efeitos adversos , Análise de Falha de Equipamento , Feminino , Humanos , Hiperplasia/diagnóstico por imagem , Masculino , Recidiva , Estudos Retrospectivos , Túnica Íntima/diagnóstico por imagem , Ultrassonografia de Intervenção
2.
Circulation ; 104(8): 856-9, 2001 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-11514368

RESUMO

BACKGROUND: The efficacy of coronary gamma-irradiation in preventing recurrent in-stent restenosis (ISR) is well established. However, brachytherapy may be less effective in very long, diffuse ISR lesions. METHODS AND RESULTS: We used serial intravascular ultrasound (IVUS) to study patients with long, diffuse ISR lesions (length, 36 to 80 mm) who were enrolled in (1) Long WRIST (Washington Radiation In-Stent Restenosis Trial), a double-blind, placebo-controlled trial of intracoronary gamma-irradiation (15 Gy at 2 mm from the source) and (2) high-dose (HD) Long WRIST, a registry that used a dose prescription of 18 Gy at 2 mm from the source. IVUS was performed using automated pullback (0.5 mm/s). Stent, lumen, and intimal hyperplasia were measured at 2-mm intervals. Complete postintervention and follow-up IVUS imaging was available in 30 irradiated and 34 placebo patients from Long WRIST and in 25 patients from HD Long WRIST. Stent length was longer in HD Long WRIST than in placebo or treated patients in Long WRIST (P=0.0064 and P=0.0125, respectively). Otherwise, baseline measurements were similar. At follow-up, the minimum lumen area was largest in the HD Long WRIST patients (4.0+/-1.4 mm(2)); areas were 2.9+/-1.0 mm(2) in irradiated patients in Long WRIST and 1.9+/-1.1 mm(2) in placebo patients in Long WRIST (P<0.005 for all comparisons). CONCLUSIONS: - Serial IVUS analysis shows that gamma-irradiation reduces recurrent in-stent neointimal hyperplasia in long, diffuse ISR lesions; however, it is even more effective when given at a higher dose.


Assuntos
Raios gama/uso terapêutico , Oclusão de Enxerto Vascular/prevenção & controle , Revascularização Miocárdica , Stents , Ultrassonografia de Intervenção , Braquiterapia/métodos , Doença das Coronárias/cirurgia , Relação Dose-Resposta à Radiação , Método Duplo-Cego , Oclusão de Enxerto Vascular/classificação , Oclusão de Enxerto Vascular/diagnóstico , Humanos , Pessoa de Meia-Idade , Revascularização Miocárdica/efeitos adversos , Revascularização Miocárdica/métodos , Fatores de Risco , Prevenção Secundária , Stents/efeitos adversos , Resultado do Tratamento , Grau de Desobstrução Vascular/efeitos da radiação
3.
Circulation ; 103(2): 188-91, 2001 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-11208674

RESUMO

BACKGROUND: The relation between lesion length and effectiveness of brachytherapy is not well studied. METHODS AND RESULTS: We compared serial (postintervention and follow-up) intravascular ultrasound findings in 66 patients with native coronary artery in-stent restenosis (ISR) who were treated with (192)Ir (15 Gy delivered 2 mm away from the radiation source). Patients were enrolled in the Washington Radiation for In-Stent Restenosis Trial (WRIST; ISR length, 10 to 47 mm; n=36) or Long WRIST (ISR length, 36 to 80 mm; n=30). External elastic membrane, stent, lumen, and intimal hyperplasia (IH; stent minus lumen) areas and source-to-target (intravascular ultrasound catheter to external elastic membrane) distances were measured. Postintervention stent areas were larger in WRIST and smaller in Long WRIST patients (P:<0.0001). At follow-up, maximum IH area significantly increased in both WRIST and Long WRIST patients (P:<0.0001 for both), but this increase was greater in Long WRIST patients (P:=0.0006). Similarly, minimum lumen cross-sectional area significantly decreased in both WRIST and Long WRIST patients (P:<0.05 and P:<0.0001, respectively), but this decrease was more pronounced in Long WRIST patients (P:=0.0567). The maximum source-to-target distance was longer in Long WRIST than in WRIST, and it correlated directly with ISR length (r=0.547, P:<0.0001). Overall, the change in minimum lumen area and the change in maximum IH area correlated with the maximum source-to-target distance (r=0.352, P:=0.0038 and r=0.523, P:<0.0001 for WRIST and Long WRIST, respectively). The variability (maximum/minimum) in IH area at follow-up also correlated with the maximum source-to-target distance (r=0.378, P:<0.0001). CONCLUSIONS: Brachytherapy may be less effective in longer ISR lesions because of the greater variability and longer source-to-target distances in diffuse ISR.


Assuntos
Braquiterapia , Estenose Coronária/diagnóstico por imagem , Estenose Coronária/radioterapia , Raios gama/uso terapêutico , Stents , Ultrassonografia de Intervenção , Braquiterapia/normas , Reestenose Coronária/prevenção & controle , Estenose Coronária/prevenção & controle , Vasos Coronários/diagnóstico por imagem , Seguimentos , Humanos , Hiperplasia , Radioisótopos de Irídio/uso terapêutico , Ensaios Clínicos Controlados Aleatórios como Assunto , Resultado do Tratamento , Túnica Íntima/diagnóstico por imagem , Ultrassonografia de Intervenção/métodos
5.
Am J Cardiol ; 86(12): 1318-21, 2000 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-11113405

RESUMO

We sought to determine if axial and circumferential distribution of plaque before stenting determines the axial and circumferential distribution of subsequent intimal hyperplasia (IH). We studied 22 patients with a single Palmaz-Schatz stent implanted in a native coronary artery, who underwent intravascular ultrasound (IVUS) imaging before intervention, after stenting, and at 6-month follow-up. For each lesion, 7 locations were analyzed: proximal and distal reference, proximal and distal edge of the stent, proximal and distal location within the body of the stent, and the articulation. Pre- and postintervention and follow-up image slices were precisely aligned and analyzed for pre- and postintervention plaque area and follow-up IH area and thickness. The location of maximal IH area was at or adjacent to the location of maximal preintervention plaque in 17 of 22 of the patients (77%). Similiarly, the circumferential distribution of IH at follow-up paralleled the eccentricity pattern of the native plaque burden in 69% (24 of 35 slices). Using multivariant analysis, the strongest predictor of IH was preintervention plaque area (p = 0.001). IH accumulates axially and circumferentially preferentially at the site of maximal preintervention plaque.


Assuntos
Doença da Artéria Coronariana/patologia , Vasos Coronários/patologia , Stents , Túnica Íntima/patologia , Angioplastia Coronária com Balão/instrumentação , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/terapia , Vasos Coronários/diagnóstico por imagem , Feminino , Seguimentos , Humanos , Hiperplasia , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Túnica Íntima/diagnóstico por imagem , Ultrassonografia de Intervenção
6.
Am J Cardiol ; 84(11): 1298-303, 1999 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-10614794

RESUMO

Two hundred eighty-four consecutive patients with 438 native coronary artery stenoses were enrolled prospectively in a study of intravascular ultrasound (IVUS)-guided provisional percutaneous transluminal coronary angioplasty (PTCA): (1) IVUS-guided, aggressive lesion-site media-to-media balloon sizing, (2) IVUS assessment of residual lumen dimensions to identify optimal PTCA results (minimum lumen area > or =65% of the average of the proximal and distal reference lumen areas or > or =6.0 mm2 and no major dissection), and (3) liberal stent crossover. Overall, 206 stenoses in 134 patients were treated with PTCA alone. Reasons for crossover were flow-limiting or lumen compromising dissections in 28% of patients or a suboptimal IVUS minimum lumen area in 72% of patients. Sixty-three stenoses (27%) were treated with Gianturco-Roubin stents and 169 (73%) with Palmaz-Schatz stents. The clinical success rate and major in-hospital complication rates were similar in the optimal PTCA and stent crossover groups. At 1 year, 42 patients (15%) with 53 stenoses (12%) underwent revascularization: 8% of stenoses in the PTCA group and 16% in the stent crossover group. In approximately half of the patients treated using an IVUS guided aggressive PTCA strategy, stent implantation could be avoided without sacrificing an increase in acute complications or late clinical outcome. This provides an alternative strategy for interventionalists less inclined to use routine elective stenting.


Assuntos
Angioplastia Coronária com Balão/métodos , Doença das Coronárias/terapia , Vasos Coronários/diagnóstico por imagem , Stents , Ultrassonografia de Intervenção , Angiografia Coronária , Doença das Coronárias/diagnóstico por imagem , Estudos Cross-Over , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Implantação de Prótese , Recidiva , Resultado do Tratamento
7.
Am J Cardiol ; 83(10): 1427-32, 1999 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-10335756

RESUMO

Serial volumetric intravascular ultrasound (IVUS) was used to study de novo, nontreated left main coronary arteries (LMCAs) in 31 patients. Using an automated contour detection algorithm, analysis of 7.2 +/- 2.5 mm long segments included arterial, lumen, and plaque volumes and plaque burden (plaque/arterial volumes). During follow-up (7.7 +/- 2.4 months), the percent change in lumen volume correlated with the percent change in arterial volume (r = 0.897, p <0.0001), but not with the percent change in plaque volume (r = 0.066, p = 0.7263). Percent changes in arterial volume correlated with percent changes in plaque + media volume (r = 0.448, p = 0.0115), indicating arterial remodeling. However, there was a spectrum of responses ranging from inadequate remodeling (decrease in lumen volume despite no increase or a decrease in plaque volume: i.e., arterial shrinkage) to overcompensation (an increase in lumen volume despite an increase in plaque volume). Serial volumetric IVUS (1) confirms the existence of both positive and negative remodeling in LMCA, and (2) shows that in moderate LMCA disease, luminal changes resulted primarily from positive versus negative remodeling, not plaque progression and/or regression.


Assuntos
Doença das Coronárias/diagnóstico por imagem , Doença das Coronárias/patologia , Vasos Coronários/diagnóstico por imagem , Vasos Coronários/patologia , Ultrassonografia de Intervenção , Idoso , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/patologia , Progressão da Doença , Humanos , Processamento de Imagem Assistida por Computador , Pessoa de Meia-Idade , Estudos Prospectivos
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