Intravascular Ultrasound-guided Treatment For Unprotected Left Main Coronary Artery Disease

Objectives The purpose of this study was to evaluate the efficacy of an intravascular ultrasound(IVUS)-guided strategy for patients with unprotected left main coronary artery disease. The research object of this study was patients with angiographically determinate unprotected left main coronary artery(ULMCA) disease undergoing interventional treatment. Long-term follow-up was to evaluate the efficacy of an intravascular ultrasound(IVUS)-guided strategy for patients in target lesion revascularization(TLR) and major adverse cardiac events(including all-cause mortality, stent thrombosis, and myocardial infarction).Methods ⑴ Determine Lesions: Coronary angiography(CAG) was performed to 85 patients who were found via the radial artery approach, using digital subtraction angiography(X-Ray System, Philips);⑵ Preoperative Evaluation: The IVUS imaging protocol(Boston Scientific) was performed to the IVUS-guided group. Intravascular ultrasound analysis measured minimal lumen diameter(MLD), minimal lumen area(MLA), and area stenosis(AS %). Quantitative coronary angiography was performed to the CAG-guided group. Minimal lumen diameter, minimal lumen area, and area stenosis were measured by angiography; ⑶ Percutaneous transluminal coronary angioplasty(PTCA) and Stent Implantation: The indications for stent implantation of the IVUS-guided group were MLD<2.8mm and MLA<6mm2. The indications for stent implantation of the CAG-guided group were diameter stenosis≧50%. On the basis of the CAG and IVUS evaluation, the operator chose the appropriate stents for the IVUS-guided group. Repeat the IVUS examination after stent implantation. Chose a larger balloon or a higher inflation pressures if the effect was not satisfied because of incomplete expansion or incomplete stent apposition. On the basis of the QCA evaluation, the operator chose the appropriate stents for the CAG-guided group. Repeat the CAG examination after stent implantation. Chose a larger balloon or a higher inflation pressures if the effect was not satisfied because of incomplete expansion or incomplete stent apposition;⑷ Follow-up Indexes: Clinical follow-up was scheduled at 30 days, 3 months, 6 months, and 12 months. Follow-up information was obtained through outpatients’ examination, telephone interviews. The follow-up indexes are target lesion revascularization, and major adverse cardiac events(MACE) included all-cause mortality, stent thrombosis, and myocardial infarction.Results ⑴ Larger MLD, larger MLA, and lower AS% were measured in the IVUS-guided group compared with CAG-guided group(2.16±0.38 mm versus 1.61±0.62 mm, P=0.020; 4.83±1.63mm2 versus 2.52±1.87mm2, P=0.003; 64.43±9.18% versus 77.08±7.31%, P=0.014);⑵ Longer stent lengths and larger stent sizes were used in the IVUS-guided group compared with CAG-guided group(14.40±5.35 mm versus 12.12±4.25 mm, P=0.006; 3.64±0.26 mm versus 3.35±0.36 mm, P=0.026). Larger balloon sizes and higher inflation pressure were also used in the IVUS-guided group compared with CAG-guided group(3.96±0.52 mm versus 3.79±0.41 mm, P=0.031; 17.06±2.92 atm versus 14.52±2.52 atm, P=0.009);⑶ IVUS-guided group was strongly associated lower 12 months rates of MACE without increasing periprocedural MI(6.1% versus 19.2%, P=0.019). IVUS-guided group compared with CAG-guided group was associated with reduced 12 months rates of all-cause mortality which was statistically significant(6.1% versus 13.5%, P=0.044). Time-to-event data were summarized as Kaplan-Meier estimates and were statistically significant(6.1% versus 13.5%, Log rank P=0.044). IVUS-guided group had a lower incidence in myocardial infarction, stent thrombosis, or target lesion revascularization, although long-term follow-up showed no significant difference in these indexes(P>0.05).Conclusions IVUS can make up for the deficiency of CAG. IVUS can fully assess the left main coronary artery disease, and nature of the lesions, which is helpful for adequate assessment of the condition, stent selection, and stents release applications. IVUS guidance was associated with a reduction in postoperative complications.