Clinical Outcome Comparison of Everolimus- and Biolimus-eluting Stents in Patients with Acute Myocardial Infarction / 대한내과학회지

BACKGROUND/AIMS: We compared the efficacy and safety of the second-generation everolimus-eluting stent (EES) and the third generation biolimus-eluting stent (BES) in patients with acute myocardial infarction (AMI). METHODS: We analyzed 629 consecutive patients (mean age 65.1 +/- 11.2 years, 426 males) with AMI undergoing percutaneous coronary intervention from February 2008 to April 2012. They were divided into two groups according to stent type (EES group, n = 426; BES group, n = 203). The primary end-point was 2-year major adverse cardiac events (MACEs), defined as the composite of all-cause death, myocardial infarction, target vessel revascularization, non-target vessel revascularization and target lesion revascularization. The secondary end-point was 2-year target lesion failure (TLF). RESULTS: There were no significant differences in baseline characteristics, except that the patients with EES had a significantly higher prevalence of diabetes mellitus (34.7 vs. 22.7%, p = 0.002) and were older (67.1 +/- 11.3 vs. 64 +/- 12.9 years, p = 0.039) compared with the patients with BES. After propensity score matching, 2-year clinical outcomes showed no differences in composite MACEs or TLF between the two groups. Multivariate Cox regression analysis showed that stent type was not a predictor of 2-year mortality or MACEs. However, older age (hazard ratio [HR] 1.037, 95% confidence interval [CI] 1.014-1.060, p = 0.001), diabetes mellitus (HR 2.247, 95% CI 1.426-3.539, p = 0.001) and a left ventricular ejection fraction < or = 45% (HR 3.007, 95% CI 1.978-4.573, p = 0.001) were independent predictors for 2-year MACEs in patients undergoing EES or BES. CONCLUSIONS: Patients with BES had similar clinical 2-year outcomes compared with EES patients with AMI.

Comparison of Clinical Outcomes after Implantation of First- and Second-Generation Overlapping Drug-Eluting Stents to Treat Diffuse Long Coronary Lesions / 대한내과학회지

BACKGROUND/AIMS: Despite improved revascularization techniques, the clinical outcomes of patients with diffuse coronary artery lesions after percutaneous coronary intervention are unsatisfactory. However, few studies have compared the efficacy of first- and second-generation drug-eluting stents (DES) in patients with diffuse long coronary artery lesions. METHODS: Between January 2006 and July 2012, 364 patients who were treated with DES for long coronary artery stenosis (> 30 mm) were enrolled in this study and assigned to either Group I (first-generation DES, 62.3 +/- 10.4 years, 136 males, n = 183) or Group II (second-generation DES, 64.3 +/- 10.7 years, 134 males, n = 181). The incidence of major adverse cardiac events (MACE) was compared between the two groups over 2 years of follow-up, and predictive factors associated with MACE were evaluated through a multivariate analysis. RESULTS: Although several coronary angiographic characteristics were different between the two groups, most demographic and baseline clinical variables were the same. The cumulative incidence of MACE was significantly higher in Group I than in Group II (25.7 vs. 6.6%; p < 0.001), mainly due to reduced target lesion revascularization (21.9 vs. 2.2%; p < 0.001). According to the results of the multivariate analysis, the use of a paclitaxel-eluting stent (PES) (hazard ratio [HR], 5.168; 95% confidence interval [CI], 2.515-10.617; p < 0.001), decreased left ventricular function (< or = 45%; HR, 3.586; 95% CI, 1.839-6.990; p < 0.001), and diabetes mellitus (HR, 2.984; 95% CI, 1.605-5.548; p < 0.001) were independent contributors to MACE. CONCLUSIONS: For patients with diffuse long coronary artery stenosis, the use of second-generation DES improved the clinical outcome compared with first-generation DES. In addition, the use of a PES, left ventricular dysfunction, and diabetes were predictors of MACE after overlapping stenting.

Statistical Methods for Multivariate Missing Data in Health Survey Research / 예방의학회지

Missing observations are common in medical research and health survey research. Several statistical methods to handle the missing data problem have been proposed. The EM algorithm (Expectation-Maximization algorithm) is one of the ways of efficiently handling the missing data problem based on sufficient statistics. In this paper, we developed statistical models and methods for survey data with multivariate missing observations. Especially, we adopted the Em algorithm to handle the multivariate missing observations. We assume that the multivariate observations follow a multivariate normal distribution, where the mean vector and the covariance matrix are primarily of interest. We applied the proposed statistical method to analyze data from a health survey. The data set we used came from a physician survey on Resource-Based Relative Value Scale(RBRVS). In addition to the EM algorithm, we applied the complete case analysis, which used only completely observed cases, and the available case analysis, which utilizes all available information. The residual and normal probability plots were evaluated to access the assumption of normality. We found that the residual sum of squares from the EM algorithm was smaller than those of the complete-case and the available-case analyses.