Prognostic Significance of Serum Creatinine Concentration for In-Hospital Mortality in Patients With Acute Myocardial Infarction Who Underwent Successful Primary Percutaneous Coronary Intervention (from the Heart Institute of Japan Acute Myocardial Infarction [HIJAMI] Registry) Jun-ichi Yamaguchi, MD, Hiroshi Kasanuki, MD, Yasuhiro Ishii, MD, Masahiro Yagi, MD, Hiroshi Ogawa, MD, Shin-ya Fujii, MD, Hiroshi Koganei, MD, Hisayuki Okada, MD, Hirotaka Kimura, MD, Toshinobu Horie, MD, Kazuo Haze, MD, Tetsuya Sumiyoshi, MD, and Takashi Honda, MD, for the HIJC Study Group This study evaluated the impact of serum creatinine levels on in-hospital mortality in 1,359 consecutive patients with acute myocardial infarction (from a Jap- anese prospective multicenter registry) who under- went successful primary percutaneous coronary inter- vention (PCI). Even in the patients who underwent successful primary PCI, the in-hospital mortality of patients with mild (1.2 < creatinine < 2.0 mg/dl) and severe (creatinine >2.0 mg/dl) renal dysfunction was greater (17.1% and 34.5%, respectively) than that of patients without renal dysfunction (3.9%) (relative risk [RR] 1.72, 95% confidence interval [CI] 0.94 to 3.14, p  0.080; and RR 4.26, 95% CI 1.48 to 12.27, p <0.0001, respectively). 2004 by Excerpta Med- ica, Inc. (Am J Cardiol 2004;93:1526 –1528) P atients with renal dysfunction are at an increased risk for cardiovascular disease and for adverse cardiovascular outcomes. 1 In multiple epidemiologic studies and clinical trials, renal dysfunction has also been shown to be an independent predictor of survival in patients with acute coronary syndrome and acute myocardial infarction (AMI). 2–5 Primary percutaneous coronary intervention (PCI) for AMI has demon- strated a superior reperfusion rate compared with fi- brinolytic therapy and is becoming the major strategy for acute reperfusion. After the introduction of intra- coronary stents, primary PCI was shown to be safe and feasible in most patients with AMI. This study therefore examined the impact of the serum creatinine concentration on the in-hospital mortality of patients with AMI who underwent successful primary PCI in the recent reperfusion era. ••• The study population was drawn from a Japanese multicenter observational prospective registered co- hort, the Heart Institute of Japan Acute Myocardial Infarction registry. 6 In brief, 3,021 consecutive pa- tients with AMI admitted alive to 17 Japanese hospi- tals were registered from January 1999 to June 2001. Emergency coronary angiography (24 hours after AMI onset) was performed in 71.9% (2,249 patients), and 48.0% (1,451 patients) received primary PCI. The angiographic success rate of PCI was 93.7%, and stents were implanted in 76.5% (1,040 patients) of the patients who underwent primary PCI. Overall in-hos- pital mortality was 9.7%, whereas it was 6.4% in the patients with successful PCI. The main cause of in- hospital death was cardiogenic shock (3.3%). Primary PCI was defined as percutaneous coronary revascularization 24 hours after the onset of AMI without the use of intravenous or intracoronary fi- brinolytic agents as the initial therapy to restore cor- onary blood flow. Reperfusion success was defined as Thrombolysis In Myocardial Infarction grade 3 flow. 7 We examined 1,359 consecutive patients in whom primary PCI was successful. The patients were ini- tially classified into 3 groups on the basis of the serum creatinine concentration measured in milligrams per deciliter (serum creatinine cut-off points of 1.2 and 2.0 mg/dl) on admittance. Normal renal function and mild and severe renal dysfunction were defined as serum creatinine concentrations of 1.2 mg/dl, 1.2 but 2.0 mg/dl, and 2.0 mg/dl, respectively. Patients receiving regular hemodialysis were excluded from the study. The 3 groups of patients were examined before detailed analyses were done to allow a suffi- cient number of patients in each group for multivariate analysis and to ensure that the cut-off points of the serum creatinine concentration would be clinically meaningful. Univariate and multivariate relative risks (RRs) were calculated for 3 renal risk quartiles using the serum creatinine concentration on presentation. Continuous variables are expressed as means  SDs or medians (25th percentile, 75th percentile) and were From the Department of Cardiology, The Heart Institute of Japan, Tokyo Women’s Medical University, Tokyo; Saitama Cardiovascular and Respiratory Center, Saitama; Osaka City General Hospital, Osaka; The Sakakibara Heart Institute, Tokyo; and Saiseikai Kumamoto Hos- pital, Kumamoto, Japan. Dr. Yamaguchi’s address is: Department of Cardiology, The Heart Institute of Japan, Tokyo Women’s Medical University, 8-1 Kawada-cho Shinjuku-ku, 162-8666, Tokyo, Japan. E-mail: junichi.yamaguchi@nifty.com. Manuscript received January 13, 2004; revised manuscript received and accepted February 24, 2004. 1526 ©2004 by Excerpta Medica, Inc. All rights reserved. 0002-9149/04/$–see front matter The American Journal of Cardiology Vol. 93 June 15, 2004 doi:10.1016/j.amjcard.2004.02.065