Role of Intracoronary Ultrasound After High-Pressure Stent Implantation
Background: Poststent high-pressure balloon inflation has been shown to improve clinical outcomes. However, it is unknown whether intracoronary ultrasound (ICUS) provides additional clinical guidance after initial high-pressure balloon inflation is used during stent placement. Thus the purpose of this study was to determine if stent deployment techniques are improved with ICUS imaging despite an optimal angiographic result achieved with high-pressure balloon inflation.
Methods and Results: Prospective data were collected on 96 consecutive patients in whom 151 stents were deployed. Stents and high-pressure balloons were angiographically sized 1:1 by visual estimation. High-pressure (>=12 atm in all cases) balloon inflations were continued until angiographic completion (<10% residual stenosis), after which index ICUS imaging was performed. Stent apposition, symmetry, and lumen dimensions were evaluated. An optimal ICUS result was defined as full apposition of the stent, symmetry ratio >=0.80, and acute gain >=0.80 of the reference lumen area. If inadequate ICUS results were found, further dilations with higher pressures or larger balloons and subsequent stent reevaluation with ICUS were performed. Sixty-nine (46%) stents required additional balloon inflations. Of these stents, 35 (23%) had initial acute gains that were <80% of the reference lumen area. Forty-six (30%) stents were found to have unapposed struts and 24 (16%) had a symmetry ratio <0.80. In patients requiring additional inflations, minimum stent area increased from 7.6 ± 2.2 mm to 9.2 ± 2.4 mm (P < .0001). Similarly, complete stent apposition improved from 33% to 68% of total stents (P < .0001). After initial ICUS, higher-pressure dilations were performed in 40 patients, whereas larger balloons greater than or equal to ICUS reference vessel diameter were used in 33 patients. Follow-up was obtained in 95 (99%) patients. The overall major adverse cardiac event rate at 6 months was 9.3%, which consisted of 8 target vessel revascularizations and 1 abrupt closure requiring repeat intervention.
Conclusions: Even when poststent high-pressure balloon inflation achieves an optimal angiographic result, ICUS assists in optimizing acute gain, symmetry, and apposition of intracoronary stents in approximately 50% of patients. Moreover, ICUS guidance is associated with low rates for target vessel revascularization and major adverse cardiac events at 6-month follow-up.
The use of stents as initial interventional treatment of coronary artery disease has been shown to be clinically superior to that of balloon percutaneous transluminal coronary angioplasty and to provide long-term benefits. Stents have been used successfully in de novo coronary lesions, chronic total occlusions, and saphenous vein bypass graft stenoses. Despite the superior results of stents, suboptimal deployment may lead to subacute thrombosis and/or restenosis caused by neointimal hyperplasia. Moreover, reductions in restenosis rates have been demonstrated by increasing acute gain and decreasing elastic recoil of the treated vessel wall.
Previous work with intracoronary ultrasound (ICUS) has proven that visual or quantitative angiographic measurements of vessel dimensions for stent expansion and deployment appear to be inadequate. Repeat inflations with larger balloons or higher-pressure inflations are often necessary to improve stent apposition and optimize luminal cross-sectional area (CSA). Furthermore, high-pressure dilation under ICUS guidance may improve luminal CSA and reduce stent restenosis. Currently, high-pressure balloon dilation with the use of a balloon with a diameter equal to or slightly larger than the angiographic reference segment is used routinely. Despite this accepted practice, it is unknown whether stent apposition, symmetry, and optimal expansion are routinely achieved after angiographically guided high-pressure balloon dilation. It has been suggested that ICUS is not routinely necessary after high-pressure dilation. The purpose of this study was to determine if stent deployment techniques are improved by ICUS imaging despite an optimal angiographic result achieved with high-pressure balloon dilation.
Background: Poststent high-pressure balloon inflation has been shown to improve clinical outcomes. However, it is unknown whether intracoronary ultrasound (ICUS) provides additional clinical guidance after initial high-pressure balloon inflation is used during stent placement. Thus the purpose of this study was to determine if stent deployment techniques are improved with ICUS imaging despite an optimal angiographic result achieved with high-pressure balloon inflation.
Methods and Results: Prospective data were collected on 96 consecutive patients in whom 151 stents were deployed. Stents and high-pressure balloons were angiographically sized 1:1 by visual estimation. High-pressure (>=12 atm in all cases) balloon inflations were continued until angiographic completion (<10% residual stenosis), after which index ICUS imaging was performed. Stent apposition, symmetry, and lumen dimensions were evaluated. An optimal ICUS result was defined as full apposition of the stent, symmetry ratio >=0.80, and acute gain >=0.80 of the reference lumen area. If inadequate ICUS results were found, further dilations with higher pressures or larger balloons and subsequent stent reevaluation with ICUS were performed. Sixty-nine (46%) stents required additional balloon inflations. Of these stents, 35 (23%) had initial acute gains that were <80% of the reference lumen area. Forty-six (30%) stents were found to have unapposed struts and 24 (16%) had a symmetry ratio <0.80. In patients requiring additional inflations, minimum stent area increased from 7.6 ± 2.2 mm to 9.2 ± 2.4 mm (P < .0001). Similarly, complete stent apposition improved from 33% to 68% of total stents (P < .0001). After initial ICUS, higher-pressure dilations were performed in 40 patients, whereas larger balloons greater than or equal to ICUS reference vessel diameter were used in 33 patients. Follow-up was obtained in 95 (99%) patients. The overall major adverse cardiac event rate at 6 months was 9.3%, which consisted of 8 target vessel revascularizations and 1 abrupt closure requiring repeat intervention.
Conclusions: Even when poststent high-pressure balloon inflation achieves an optimal angiographic result, ICUS assists in optimizing acute gain, symmetry, and apposition of intracoronary stents in approximately 50% of patients. Moreover, ICUS guidance is associated with low rates for target vessel revascularization and major adverse cardiac events at 6-month follow-up.
The use of stents as initial interventional treatment of coronary artery disease has been shown to be clinically superior to that of balloon percutaneous transluminal coronary angioplasty and to provide long-term benefits. Stents have been used successfully in de novo coronary lesions, chronic total occlusions, and saphenous vein bypass graft stenoses. Despite the superior results of stents, suboptimal deployment may lead to subacute thrombosis and/or restenosis caused by neointimal hyperplasia. Moreover, reductions in restenosis rates have been demonstrated by increasing acute gain and decreasing elastic recoil of the treated vessel wall.
Previous work with intracoronary ultrasound (ICUS) has proven that visual or quantitative angiographic measurements of vessel dimensions for stent expansion and deployment appear to be inadequate. Repeat inflations with larger balloons or higher-pressure inflations are often necessary to improve stent apposition and optimize luminal cross-sectional area (CSA). Furthermore, high-pressure dilation under ICUS guidance may improve luminal CSA and reduce stent restenosis. Currently, high-pressure balloon dilation with the use of a balloon with a diameter equal to or slightly larger than the angiographic reference segment is used routinely. Despite this accepted practice, it is unknown whether stent apposition, symmetry, and optimal expansion are routinely achieved after angiographically guided high-pressure balloon dilation. It has been suggested that ICUS is not routinely necessary after high-pressure dilation. The purpose of this study was to determine if stent deployment techniques are improved by ICUS imaging despite an optimal angiographic result achieved with high-pressure balloon dilation.
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