Intravascular Ultrasound in Stent Implantation for Coronary Artery Disease

BACKGROUND: Stent under-expansion and procedurally related abnormal lesion morphologies (e.g. dissection, thrombus) are associated with stent restenosis and acute, subacute and chronic thrombosis. OBJECTIVE: To explore whether larger post-procedural final minimum stent area can be acquired and more procedurally related complications can be identified in stent implantation guided by intravascular ultrasound. DESIGN, TIME AND SETTING: Retrospective analysis was performed at the Heart Center of Beijing Chaoyang Hospital, Capital Medical University between January 2004 and February 2005. PARTICIPANTS: Fifty patients with coronary artery disease with 52 lesions were enrolled in the study and underwent stenting guided by intravascular ultrasound. The patients were characterized as non-diffused lesion with vessel diameter ≥ 2.5 mm. Patients with severe left main lesion were excluded. METHODS: Qualitative and quantitative analyses were carried out in 50 patients with 52 lesions before and after stent implantation. The stent diameter and the end-point of therapy were determined by intravascular ultrasound standard. MAIN OUTCOME MEASURES: The differences of end point for stent implantation and the enlargement of lumen area gained by stent implantation were compared between cardioangiography and by intravascular ultrasound. RESULTS: The average stent diameter guided by intravascular ultrasound was larger than by cardioangiography (P=0.011); the peak balloon pressure was higher in intravascular ultrasound group than cardioangiography group (P＜0.001), and area stenosis percentage measured by quantitative coronary angiogram was smaller in intravascular ultrasound group than cardioangiography group (P=0.044). ② Cardioangiography showed success rate was 96.2% and intravascular ultrasound showed the success rate was only 37.7% after first balloon high-pressure dilation. Intravascular ultrasound subgroup analysis showed higher peak balloon pressure (P＜0.001), larger lumen diameter (P＜0.001), larger lumen area (P＜0.001), and smaller area stenosis percentage (P ＜ 0.001). No obvious stenosis was found at the proximal and distal segments of the stent observed by cardioangiography, while atherosclerotic lesions at proximal segment were found in 39 cases (75.0%) and at distal segment were in 23 cases (44.2%) observed by intravascular ultrasound. The lumen area was larger in non-fatty plaque than in fatty plaque after stent implantation (P＜0.001). Compared with non-fatty plaque, the enlargement of vessel area was 1.30 mm2 smaller, while plaque compression was 0.48 mm^2 larger. CONCLUSION: Stent implantation guided by intravascular ultrasound can acquire larger final lumen area and identify more procedurally related complications.