Risk Factors Associated with Hemodynamic Instability during Stent Implantation in Unprotected Left Main Lesions without Routine IABP: Identification of the High Risk Patients

Background and Objectives : Percutaneous coronary intervention (PCI) of unprotected left main coronary artery (LMCA) stenosis is a promising approach during this era of drug-eluting stents. However, there is no available hemodynamic data on these type patients during the performance of LMCA stenting. The purpose of this study was to determine the risk factors affecting hemodynamic stability during LMCA stenting, and to evaluate whether hemodynamic support such as inotropics or intra-aortic balloon pump (IABP) is needed, based on the risk factors. Subjects and Methods : From July 2003 to January 2006, we enrolled 92 study patients (Male=55) who had visited Yeungnam University Hospital, Keimyung University Dongsan Hospital and InJe University Baik Hospital in Busan and they were all were diagnosed with angiographically detected unprotected LMCA stenosis. Group 1 (n=69) included those patients who did not need hemodynamic support during PCI. Group 2 (n=23) included patients who needed hemodynamic support during PCI. All patients had stents deployed in the LMCA lesions without hemodynamic support; the clinical, angiographic and procedural outcomes were compared between the two groups after the procedure. Results : The baseline patient characteristics were not statistically different between the two groups. On univariate analysis, Group 2 had more patients diagnosed with acute myocardial infarction (AMI) than Group 1 (40% vs. 15%, respectively, p=0.014). Group 1 had a greater frequency of an increased left ventricular (LV) ejection fraction than Group 2 (60±10 vs. 47±11, respectively, p=0.01). Regarding the lesion location in the LMCA, Group 2 had relatively more lesions at bifurcated locations than Group 1 (44% vs. 78%, respectively, p=0.004). Group 2 required more complex techniques to repair lesions, such as kissing or crush stenting, than did Group 1 (19% vs. 48%, respectively, p=0.006). Multivariate logistic regression analysis showed that the presence of AMI (Odds Ratio (OR)=3.74, p=0.014), a complex stenting procedure such as kissing or crushing (OR=3.99, p=0.006), a bifurcated lesion (OR=4.58, p=0.004) and poor LV function (OR=9.95, p=0.0001) were independent risk factors for hemodynamic instability during LMCA stenting. Conclusion : The most important risk factor for hemodynamic instability during LMCA stenting was LV function. Therefore, preparation for hemodynamic support, including IABP before the procedure, is necessary for the high risk patients.