All consecutive patients with AMI, who were admitted and underwent primary or rescue PCI at The Heart Center of Chonnam National University Hospital between January 1997 and December 1999, were included in this study. All patients had chest pain for a duration of less than 6 hours and prolonged chest pain for more than 30 minutes not responsive to nitroglycerin or ST elevation of more than 1 mV in two or more limb leads or 2 mV in two consecutive precordial leads. Primary PCI was performed in 177 patients (59.4±9.7 years-old, M:F=141:36) and rescue PCI in 31 patients (59.7±11.4 years-old, M:F=25:6). The two hundred and eight patients were divided into two groups; Group I (n=86, 59.9±9.3 years-old, M:F=64:22, CRP less than 1 mg/dL) and Group II (n=122, 59.1±10.4 years-old, M:F=102:20, CRP higher than 1 mg/dL), and the clinical and angiographic characteristics, success rate of the PCI and the one-month, six-month and 12-month mortality were compared retrospectively between the two groups during a one-year clinical follow-up.

A blood sample was obtained on arrival at the emergency room and stored in a refrigerator. The serum level of the CRP was measured by the latex photometric immunoassay method, and 1 mg/dL was set as the cut-off value for the comparison between the high and low groups. The left ventricular ejection fraction was compared by the Simpson method using two-dimensional echocardiography. A coronary angiogram was performed through the femoral or radial arteries. Coronary artery lesions were classified using the American College of Cardiology/American Heart Association system, in which a stenosis of more than 75% defined as a significant lesion¹¹⁾. The lesion location, involved vessel number, lesion characteristics and presence of an intracoronary thrombus on the coronary angiogram were compared between the two groups, and the vessel patency of the infarct-related artery was assessed by the Thrombolysis in Myocardial Infarction (TIMI) flow score¹²⁾. TIMI 0 was defined as a total occlusion without any distal flow below the lesion, TIMI 1 as trivial distal flow without complete visualization of the entire artery, TIMI 2 as complete visualization of the entire coronary artery with a slow flow rate and TIMI 3 as complete visualization of the entire artery with a normal flow rate. Successful revascularization was defined as a TIMI flow score of more than grade 2 and residual stenosis less than 50%¹³⁾.

Rescue PCI was defined as a dilation of the occluded infarct-related artery less than 6 hours after the onset of chest pain in patients with persistent ST segment elevation and persistent chest pain after thrombolytic therapy. Urokinase or tissue plasminogen activator was used for thrombolysis and 100–300 mg of aspirin was administered daily. Heparin was administered to maintain an activated partial thromboplastin time of about 2 times above the normal control. After discharge from the hospital, the patients were observed at the out-patient clinic at 4 week intervals, and the cardiovascular mortality was assessed at 1, 6 and 12 months after the PCI. Restenosis was defined as diameter stenosis more than 50% by the Phillips quantitative coronary angiogram analysis system.

For the statistical analysis, the unpaired t-test, Chi-square test and multiple logistic regression analysis were performed using SPSS-PC 10.0 (Statistical package for the social sciences, SPSS Inc. Chicago, IL, U.S.A.) and MS Windows®, and the results were designated as mean±standard deviation. A value of p less than 0.05 was considered as significant.

The age and sex ratios did not differ between the two groups (p=0.599, 0.104 respectively). There were no differences in these risk factors between the two groups (p=0.472, 0.373, 0.054 and 0.346, respectively) (Table 1). The incidence of cardiogenic shock was 3 cases in Group I (3.5%) and 15 in Group II (12.3%), and was higher in Group II than in group I (p=0.026) (Table 1). The values of Troponin I and T and ESR were higher than those in Group I (p<0.001, <0.001 and =0.026, respectively) (Table 1).

The time interval between the onset of symptoms and arrival at the emergency room, and the interval between the onset of symptoms and the time of the PCI did not differ between the two groups (p=0.860 and 0.843, respectively) (Table 1). The number of patients that underwent rescue PCI or primary PCI did not differ between the two groups (p=0.747) (Table 1). The number of vessels involved on diagnostic coronary angiography did not differ between the two groups (p=0.753) (Table 2). The mean number of vessels involved was 1.60±0.71 in group I and 1.54±0.71 in group II. The order of frequency in the number of vessels involved was single vessel disease, two vessel disease and three vessel disease.

Lesions involving the left anterior descending artery were the most common, but the lesion distribution did not differ between the two groups (p=0.642) (Table 2). The lesion morphology assessed according to the ACC/AHA classification was not significantly different between the two groups (p=0.634) (Table 2). An intracoronary thrombus was not different between the two groups (p=0.450) (Table 2). The mean TIMI flow grade did not differ between the two groups (p=0.087) (Table 2).

The mean TIMI flow grade represented a significant improvement after the PCI (p<0.001) (Table 4), and there was no significant difference between the two groups (p=0.863) (Table 3). The primary success rate resulted in no difference between the two groups (p=0.776) (Table 3).

The ejection fraction measured by two-dimensional echocardiography on admission did not differ between the two groups (p=0.673) (Table 1). After the PCI, the ejection fraction significantly improved in both groups (p<0.001) (Table 4).

The in-hospital death at the time of admission that presented with cardiogenic shock occurred in 2 cases in group I and 7 cases in group II. Major adverse cardiac events were observed in all patients at one, six and twelve months. Restenosis represented a significantly higher occurrence in group II (p=0.009) and the number of cases with target lesion revascularization was higher in group II (p=0.017) (Table 5).

The survival rate was analyzed during the clinical follow-up at 1, 6 and 12 months after the PCI and the survival rate was significantly lower in group II than in group I for each time period (p=0.043, 0.040 and 0.018, respectively) (Table 3).

Multiple logistic regression analysis was performed for the prediction of the one-year mortality after primary or rescue PCI. Cardiogenic shock at the time of admission, a CRP higher than 1 mg/dL and an ejection fraction lower than 40% after the PCI were independent risk factors (p<0.001, 0.001 and 0.043, respectively), whereas cardiac tropanin-T was a strong albeit not independent predictor indicating a one-year mortality. Age, sex, risk factors for atherosclerosis, target lesion location, involved vessel number and TIMI flow grade were not independent risk factors (Table 6).