Page 102 - Coronary hemodynamics in acute myocardial infarction - Matthijs Bax

Chapter 6
Statistical Analysis
Cumulative event rates were estimated using the Kaplan–Meier method and were compared with the log-rank test. Event rates are presented as Kaplan–Meier estimates at 12-year follow-up. The association of reference vessel CFVR with long- term fatal events was evaluated in 2 sets of Cox proportional hazards models. A univariable analysis was performed to identify variables associated with all- cause mortality (P<0.1). Subsequent multivariable analysis was performed with adjustments for these variables. The multivariable analysis was subsequently repeated to evaluate the association of reference vessel CFVR with cardiac mortality. Variables are presented as mean (±SD), median with first and third quartiles (Q1–Q3), or frequency (percentage), where appropriate. Comparison between groups was performed using Student t test or Fisher exact test, where appropriate. A 2-sided α level of 0.05 was considered statistically significant.
Results
Baseline and Procedural Characteristics
Reference vessel CFVR was measured in a total of 178 patients. Long-term follow- up was obtained in all these patients. Mean age of the study population was 59±13 years. Most patients had moderate-to-severe stable anginal complaints (15% Braunwald class I, 58% Canadian Cardiovascular Society class 3, 21% Canadian Cardiovascular Society class 2, and 6% Canadian Cardiovascular Society class 1). Two-vessel CAD was present in 69% of patients (123 of 178 patients). In 36% of patients (64 of 178 patients), the coronary lesion of interest was treated during the index procedure. All baseline clinical and procedural characteristics are presented in Table 1. The location of the reference vessel relative to the target vessel is presented in Table 2.
Clinical Characteristics of Patients With Normal Versus Abnormal Reference Vessel CFVR
Clinical and procedural characteristics stratified by normal or abnormal reference vessel CFVR (>2.7, and ≤2.7, respectively) are presented in Table 1. On average, patients with an abnormal reference vessel CFVR were older at the time of cardiac catheterization and less frequently had hyperlipidemia. All other clinical characteristics were balanced between the 2 groups. Lesion characteristics and epicardial lesion severity assessed either angiographically
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