This prospective study enrolled a total of 306 patients with acute STEMI (266 male and 40 female; mean age, 56.4±10 years) treated with PPCI in Beijing Shijitan Hospital (Beijing, China) between April 2011 and December 2012. Patients were included on the basis of the following criteria as described previously (12–14): i) Patients aged between 18 and 75 years; ii) patients underwent continuous ischemic chest pain for ≥30 min; iii) the electrocardiogram examination revealed ST-elevation ≥0.2 mV in leads V2 and V3 or ST-elevation ≥0.1 mV in at least two other continuous leads, and cardiac troponin-I (cTn-I)-elevation >0.05 ng/ml; iv) the coronary arteriography performed within 12 h following the onset of symptoms indicated thrombolysis in myocardial infarction bleeding grade 0–1 in culprit vessels; v) the PPCI was performed only in culprit vessels; and vi) the presence of coronary arteriography corroborated lesions in non-culprit vessel. Non-culprit lesions were defined as angiostenosis ≥70% in one or more coronary vessels with a diameter ≥2 mm vessels other than culprit vessels.

Patients were excluded for the following criteria: i) Patients with left main coronary artery disease, cardiogenic shock or complete left bundle branch block; ii) PPCI performed for both culprit and non-culprit vessels at the same time or a PPCI performance failure; iii) patients who have experienced hemodynamic instability or spontaneous ischemia following PPCI; iv) lesions and angiostenosis ≥70% in vessels remaining following SPCI; v) patients who had a history of coronary artery bypass grafting (CABG) or chronic cardiac failure; and vi) bleeding corporeality, prior administration of thrombolytic therapy, known thrombopenia or leucopenia, sever liver and renal function abnormalities, active infection, immune system and connective tissue diseases, known contraindications to aspirin or heparin, pregnancy, life expectancy <1 year, major operation within 3 months, uncontrolled hypertension, a history of ischemic or hemorrhagic stroke, intracranial diseases including aneurysm and arteriovenous malformation within 30 days, extensive trauma within 6 weeks, oral anticoagulant therapy, severe ongoing myocardial infarction-related complications or perioperative mortality.

The ethical committee of Beijing Shijitan Hospital approved the study protocol and detailed informed consent was obtained from all of the patients or their family members.

Patients were randomly divided into CR and CP groups using a table of random digits. Patients in the CR group underwent SPCI for non-culprit lesions after 7–10 days of PPCI. The PPCI was performed according to standard techniques, during which a drug-eluting stent was used. Patients in the CP group were only treated with CP following PPCI. Echocardiography was performed in both groups using a Doppler echocardiograph (Vivid; GE Healthcare Bio-Sciences, Pittsburgh, PA, USA), and left ventricular function with preserved ejection fraction was diagnosed according to the study of Paulus et al (15). Then, an intra-aortic balloon pump was inserted in patients with poor left ventricular function at the lesion site of infarct-related artery following PPCI. In addition, all patients received a single dose of oral aspirin (300 mg; Bayer Healthcare Co., Ltd., Beijing, China) and clopidogrel (300 mg; Sanofi-Aventis, Paris, France) prior to PPCI, and 100 mg/d aspirin, 75 mg/d clopidogrel orally for ≥1 year. Low molecular weight heparin was administered for 3 days following PPCI, as well as other drugs such as statins, β receptor blocker, angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker, calcium antagonists, nitrates or tirofiban.

The primary endpoints were adjudicated by the incidence of MACE at the 180- and 360-day follow-up, including cardiac death, recurrent myocardial infarction and repeated revascularization of the target-vessel. The secondary endpoints were the recurrence of angina pectoris, newly developed heart failure and bleeding events, and MACE-free survival at the 180- and 360-day follow-up. All the events were adjudicated according to the Bleeding Academic Research Consortium proposed standardized bleeding definitions (16).

Baseline demographics, including gender, age, height, weight, case history, previous medication and other clinical data of patients were collected. The content of cTn-I was recorded prior to PPCI, and thereafter every 8 h after the procedure. The levels of fasting blood glucose, hepatorenal function, blood fat, C-reactive protein and brain natriuretic peptide were detected on the second day following PPCI. The cumulative incidence of MACE, mortality, repeated revascularization of the target-vessel, recurrent myocardial infarction, recurrent angina pectoris, new heart failure and major bleeding were recorded at the 180- and 360-day follow-up. Follow-up was performed by interview.

Qualitative data are expressed as percentages, and differences between groups were analyzed using Fisher's test. Quantitative data showing normal distribution are expressed as the mean ± standard deviation, and differences between the two groups were determined by independent t-test. Quantitative data showing abnormal distribution were expressed by median (interquartile range), and differences between groups were determined by the Mann-Whitney U-test. The survival curves during the 180- and 360-day follow-up were plotted using the Kaplan-Meier method and the analyses were determined using pairwise log-rank test. All statistical tests were two-sided and the analyses were performed using SPSS version 18.0 (SPSS, Inc., Chicago, IL, USA). P<0.05 was considered to indicate a statistically significant difference.

A total of 306 patients in the trial were divided into two groups following PPCI: 148 patients (48%) in the CR group, and 158 patients (52%) in the CP group. As shown in Table I, baseline clinical characteristics were similar in the two groups, except for the mean age (58±10 vs. 55±9 years; P=0.006), patient weight (75±13 vs. 72±10 kg; P=0.024), length of hospital stay (10±6 vs. 8±7 days; P=0.008), disease time (6±4 vs. 5±3 h; P=0.014), body temperature (36.3±0.3 vs. 36.4±0.4°C; P=0.014) and left ventricular end-diastolic dimension (LVEDD; 50±4 vs. 48±4 mm; P<0.001) in the CR and CP groups, respectively. During the hospital stay, patients in the CR and CP groups received similar intra-aortic balloon counterpulsation and administration of drugs (Table II), except that significantly more CP patients were administered nitrates compared with the CR cases (94.3 vs. 75.7%, respectively; P<0.001). The information collected prior to and following PPCI did not differ between the CP and CR groups (all P>0.05; Table III).

All patients were followed-up and the clinical outcomes of the 180- and 360-day follow-up after PPCI are presented in Table IV. The incidence of recurrent angina pectoris in the CP group was significantly higher compared with that in the CR group at the 180-day follow-up (13.9 vs. 5.4%, respectively; P=0.012) and the 360-day follow-up (18.4 vs. 8.1%, respectively; P=0.009). A total of 29 cases had developed MACE symptoms by the 360-day follow-up, and the incidence of MACE in the CP group was significantly higher compared with that in the CR group (6.1 vs. 12.7%; P=0.050), and the same tendency was detected in the incidence of recurrent myocardial infarction (CP group vs. CR group, 10.1 vs. 4.1%; P=0.040). The incidence of mortality, repeated revascularization of the target-vessel, newly developed heart failure and major bleeding did not differ between the two groups (all P>0.05).

The Kaplan-Meier analysis revealed no difference in the MACE-free survival rate of patients between the CR and CP groups at the 180-day follow-up (97.3 vs. 92.4%; P>0.05; Fig. 1A). However, the MACE-free survival rate of the CR group was significantly higher compared with that of the CP group at the 360-day follow-up (93.9 vs. 87.3%; P<0.05; Fig. 1B).