Effect of Postconditioning on Myocardial Reperfusion during Primary Percutaneous Coronary Intervention Joo-Yong Hahn / Hyeon-Cheol Gwon On behalf of the POST Trial Investigators Samsung Medical Center, Sungkyunkwan University School of Medicine Thank you chairman. I’m very honored to present the results of POST trial.

Ischemic Postconditioning Repetitive reversible ischemia during early reperfusion after the prolonged ischemic insult Comparable protective effects to preconditioning in animal studies Zhao ZQ et al. Am J Physiol Heart Circ Physiol 2003 Ischemic postconditioning is repetitive reversible ischemia during early reperfusion after the prolonged ischemic insult. Animal studies have demonstrated that postconditioning has cardioprotective effects that are comparable to preconditioning.

Ischemic Postconditioning Postconditioning reduced enzymatic infarct size in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). Staat P et al. Circulation 2005, the first report in human Inconsistent results of studies using CE-MRI for infarct size Lonborg J et al. Circ Cardiovasc Interv 2010 Thuny F et al. J Am Coll Cardiol 2012 Sorensson P et al. Heart 2010 Freixa X et al. Eur Heart J 2012 Tarantini G et al. Int J Cardiol 2012 No large scale trials PostC is Protective! Enzymatic infarct size was significantly reduced in the postconditioning group compared with the control group in patients undergoing primary PCI. However, the results of studies using magnetic resonance imaging to evaluate the effects of postconditioning on infarct size are inconsistent. While 2 studies have reported that postconditioning reduces infarct size or increases myocardial salvage, infarct size did not differ significantly between the 2 treatment groups in 1 study. Notably, postconditioning showed harmful effects in other 2 studies. Until now, the efficacy and safety of postconditioning have not been demonstrated in a large-scale trial. PostC is harmful!

Objective of Study Hypothesis To evaluate the safety and efficacy of ischemic postconditioning in patients with STEMI undergoing primary PCI. Hypothesis Ischemic postconditioning can improve myocardial reperfusion after primary PCI. The objective of study was to test the safety and efficacy of postconditioning in patients with ST-segment elevation myocardial infarction undergoing primary PCI. Our hypothesis was that ischemic postconditioning can improve myocardial perfusion after primary PCI.

Trial Design A multicenter, prospective, randomized, open-label, blinded endpoint (PROBE) trial STEMI patients undergoing primary PCI Randomization after diagnostic coronary angiogram (n=700) Web-based P:C = 1:1 Stratification by infarct-related artery Postconditioning with primary PCI (n=350) Conventional primary PCI (n=350) This study was a multicenter, prospective, randomized, open-label, blinded endpoint (PROBE) trial. Patients were randomly assigned to either the postconditioning group or the conventional primary PCI group in a 1:1 ratio after diagnostic angiography. Randomization was performed using a web-based response system  and was stratified by the site of enrollment and infarct-related artery (left anterior descending artery versus non-left anterior descending artery). Myocardial reperfusion was assessed by ECG and angiogram. Patients were clinically followed-up. Assessment of myocardial reperfusion ST-segment resolution Myocardial blush grade Clinical follow-up ClinicalTrials.gov identifier: NCT00942500

Eligible patients Patients with STEMI undergoing primary PCI Inclusion criteria ST-segment elevation more than 1 mm in 2 or more contiguous leads The presence of chest pain for less than 12 hours after symptom onset Thrombolysis in Myocardial Infarction (TIMI) flow grade 0 or 1 in the infarct-related artery Target lesion in a native coronary vessel with reference diameter of 2.25 to 4.25 mm. Patients were eligible for the trial if they had acute ST-segment elevation myocardial infarction and primary PCI was planned. Inclusion criteria were as follows: 1) the presence of chest pain for less than 12 hours after symptom onset; 2) ST-segment elevation more than 1 mm in 2 or more contiguous leads; 3) Thrombolysis in Myocardial Infarction (TIMI) flow grade of 0 or 1 in the infarct-related artery; and 4) target lesion in a native coronary vessel with reference diameter of 2.25 to 4.25mm.

Exclusion Criteria Hemodynamic instability or cardiogenic shock Left bundle branch block on electrocardiogram (ECG) Left main lesion Rescue PCI after thrombolysis or facilitated PCI Non-cardiac co-morbid conditions with life expectancy <1 year or that may result in protocol non-compliance (per site investigator's medical judgment) Female of childbearing potential, unless a recent pregnancy test is negative, who possibly plan to become pregnant any time after enrollment into this study. Exclusion criteria were as follows: 1) hemodynamic instability or cardiogenic shock; 2) left bundle branch block on electrocardiogram (ECG); 3) left main lesion; 4) rescue PCI after thrombolysis or facilitated PCI; 5) non-cardiac co-morbid conditions with life expectancy <1 year or that may result in protocol non-compliance (per site investigator's medical judgment); or 6) female of childbearing potential, unless a recent pregnancy test was negative, who possibly plans to become pregnant any time after enrollment in this study.

*Staat P et al. Circulation 2005;112:2143-2148 Study Protocol Postconditioning Four episodes of 1-minute balloon occlusion and 1-minute deflation* Immediately (within 1 minute) after restoration (TIMI grade ≥2) of coronary flow (without regard to method of achieving reflow) Aspirin 300 mg and clopidogrel 600 mg Thrombus aspiration, predilation before stenting, or use of glycoprotein IIb/IIIa inhibitors were left to the operators’ discretion. PCI was performed according to standard techniques. Before the index procedure, all patients received 300 mg of aspirin and 600 mg of clopidogrel as loading doses. In the postconditioning group, immediately after restoration (TIMI grade ≥2) of coronary flow (without regard to method of restoration), an angioplasty balloon was positioned at the culprit lesion or stented segment and inflated 4 times for 1 minute with low-pressure (<6 atm) inflations, each instance of inflation separated by 1 minute of reflow. Thrombus aspiration, predilation before stenting, or use of glycoprotein IIb/IIIa inhibitors were left to the operators’ discretion. Ischemia Reperfusion Conventional PCI Postconditioning Ballooning for 1 min X 4 *Staat P et al. Circulation 2005;112:2143-2148

Endpoints Primary End point Complete ST-segment resolution (STR >70%) at 30 minutes after the procedure Secondary End Points TIMI flow grade after PCI Myocardial blush grade Major adverse cardiac events (MACE: a composite of death, reinfarction, severe heart failure*, or stent thrombosis†) at 30 days Each component of MACE at 30 days Target vessel revascularization at 30 days The primary end point was the rate of complete ST-segment resolution on ECG obtained at 30 minutes after the procedure. Complete ST-segment resolution was defined as the percentage resolution of ST-segment elevation >70%. Secondary end points included TIMI flow after PCI, myocardial blush grade, and major adverse cardiac events (a composite of death, reinfarction, severe heart failure, or stent thrombosis) at 30 days. * Heart failure with documented arterial partial pressure of oxygen less than 60 mmHg or with pulmonary edema documented radiographically or requiring intubation, 100% oxygen, or insertion of a mechanical support device. †Definite or probable stent thrombosis by the ARC definition

Sample Size Calculation Primary Endpoint The rate of complete STR The rate of complete STR in the conventional PCI group: 50% The expected rate of complete STR in the postconditioning group: 62.5% (relative increase 25%) Type I error 0.05 Sampling ratio of postconditioning : conventional PCI = 1:1 We assumed that the rate of complete ST-segment resolution in the conventional primary PCI group would be 50%. We expected that postconditioning would increase the rate of complete ST-segment resolution by 12.5% (relative increase of 25%), leading to a final percentage of 62.5%. Based on the estimated improvement in the primary endpoint, we selected a target sample size of 700 subjects, which would provide 91.7% power at the .05 significance level to detect anticipated differences and offer some protection against the inability of measuring the ECG, losses to follow-up, or smaller effect size than anticipated. A target sample size of 700 subjects would provide 91.7% power.

Independence in Trial Coordination Steering Committee 17 study investigators DSMB Data Safety Monitoring Board CTC-SMC Trial Coordinating Center CEAC Clinical Event Adjudication Committee Core Laboratory ECG and angiographic data analyses The steering committee was comprised of 17 study investigators. This study was coordinated by the Clinical Trial Center of Samsung Medical Center. ECG and angiographic data were analyzed at the core laboratory (Samsung Medical Center, Seoul, Korea) by independent observers, who were blinded to the study randomization. The independent clinical event adjudication committee, whose members were unaware of the study-group assignments, assessed all of the clinical end points. An independent data safety monitoring board reviewed data once per year. The sponsors were not involved with the protocol development or the study process, including site selection, management, and data collection and analysis. Grant Support 1) The Korean Society of Interventional Cardiology 2) The Sungkyunkwan University Foundation for Corporate Collaboration 3) Medtronic Korea

Participating Centers 17 Hospitals in Republic of Korea Samsung Medical Center Samsung Changwon Hospital Kyungpook National University Hospital Hanil General Hospital Konyang University Hospital Korea University Anam Hospital Gyeongsang National University Hospital Eulji University School of Medicine Kangbuk Samsung Hospital Chungbuk National University Hospital Sejong General Hospital Daegu Catholic University Hospital Chung-Ang University Hospital Boramae Medical Center Yeungnam University Hospital Dankook University Hospital Kyung Hee Medical Center Seventeen hospitals in Republic of Korea participated in our trial.

3916 Patients were assessed 3216 Were not enrolled 478 Declined to participate 1053 Had TIMI flow grade of 2 or 3 412 Had hemodynamic instability or cardiogenic shock 47 Had left main lesions 36 Underwent rescue PCI or facilitated PCI 94 Non-cardiac co-morbid conditions with life expectancy <1 year 401 Participated in other studies 695 Had other reasons Between July 2009 and June 2012 700 Underwent randomization 350 Were assigned to postconditioning 350 Were assigned to conventional PCI 27 Did not undergo postconditioning per protocol 1 underwent coronary artery bypass grafting surgery Between July 2009 and June 2012, we screened 3916 patients with ST-segment elevation myocardial infarction undergoing primary PCI at 17 centers (Fig. 1). Of the screened patients, a total of 700 (17.9%) were enrolled and randomly assigned to either the postconditioning group (n=350) or to the conventional PCI group (n=350). One patient in the conventional PCI group underwent emergent coronary artery bypass grafting surgery due to failure of guidewire passage. Among the patients assigned to the postconditioning group, balloon occlusion immediately after reflow was performed for 4 cycles per protocol in 323 patients (92.3%). Baseline and follow-up ECG data were available for analysis in 341 patients (97.4%) of the postconditioning group and 335 patients (95.7%) of the conventional PCI group (P=0.21). 323 Underwent postconditioning per protocol 349 Underwent conventional primary PCI 341 Were included in analysis of STR 335 Were included in analysis of STR 350 Had clinical follow-up 350 Had clinical follow-up

Baseline Clinical Characteristics Postconditioning (n=350) Conventional PCI P Value Age ― yr 60±12 0.96 Male sex 276/350 (78.9%) 261/350 (74.6%) 0.18 Body mass index* 24.1±3.2 24.4±3.0 0.34 Diabetes mellitus 84/346 (24.3%) 87/346 (25.1%) 0.79 Hypertension 161/341 (46.4%) 159/349 (45.6%) 0.82 Dyslipidemia 139/345 (40.3%) 0.16 Current smoking 184/349 (52.7%) 182/348 (52.3%) 0.91 Previous myocardial infarction 10/344 (2.9%) 9/348 (2.6%) 0.80 Previous revascularization 20/346 (5.8%) 16/349 (4.6%) 0.48 Cerebrovascular disease 10/346 (2.9%) 16/348 (4.6%) 0.24 Chronic renal failure 4/345 (1.2%) 2/348 (0.6%) 0.45 Ejection fraction (%) 50·0 (10.9) 50·2 (11.6) 0.88 Baseline clinical characteristics were well-balanced between the 2 groups. Mean age was 60 and most patients were male.

Angiographic Findings Postconditioning (n=350) Conventional PCI P Value Number of diseased vessels 0.19 1 189/350 (54.0%) 165/350 (47.1%) 2 99/350 (28.3%) 115/350 (32.9%) 3 62/350 (17.7%) 70/350 (20.0%) Infarct-related artery 0.90 Left anterior descending 163/350 (46.6%) 157/350 (44.9%) Left circumflex 38/350 (10.9%) 40/350 (11.4%) Right coronary artery 149/350 (42.6%) 153/350 (43.7%) TIMI flow before PCI 328/350 (93.7%) 324/347 (93.4%) 8/350 (2.3%) 7/347 (2.0%) 2/3 14/350 (4.0%) 16/347 (4.6%) Angiographic findings were also similar. Although patients had to have TIMI flow grade of 0 or 1 in the infarct-related artery, preprocedural TIMI flow was graded as 2 or 3 after core laboratory analysis in a minor portion of patients. TIMI = thrombolysis in myocardial infarction.

Procedural Findings Postconditioning (n=350) Conventional PCI P Value Symptom onset-to-reperfusion time ― min 196 (123-263) 195 (123-354) 0.91 Door-to-reperfusion time ― min 54 (43-73) 56 (44-74) 0.14 Thrombus aspiration 158/350 (45.1) 178/350 (50.9) 0.13 Direct stenting 43/350 (12.3) 51/350 (14.6) 0.38 Obtaining method of reflow 0.69 Wire passage 36/350 (10.3%) 45/349 (12.9%) 111/350 (31.7%) 114/349 (32.7%) Predilation ballooning 202/350 (57.7%) 189/349 (54.2%) 1/350 (0.3%) 1/349 (0.3%) Use of glycoprotein IIb/IIIa inhibitor 81/350 (23.1) 80/350 (22.9) 0.93 Stent implantation 337/350 (96.3) 342/350 (97.7) 0.28 Drug-eluting stent 291/337 (86.4) 295/342 (86.3) 0.97 Total stent length, mm 28.2±11.8 28.7±12.6 0.60 Stent diameter, mm 3.3±0.5 0.31 Symptom onset-to-balloon time and door-to-balloon time were not significantly different between the two groups. Predilation before stenting was performed in most patients and thrombus aspiration was performed in about half of the patients. Obtaining reflow (TIMI flow grade ≥2) in the infarct-related artery was achieved in a similar way in the postconditioning and conventional PCI groups, mostly by ballooning or thrombus aspiration.

Complete ST-segment Resolution 1˚ Endpoint Complete ST-segment Resolution (%) 100 Intention-to-treat analysis PostC Conv 20 40 60 80 100 (%) Per-protocol analysis 80 P=0.79 P=0.80 60 40.5% 41.5% 40.6% 41.6% 40 20 The primary end point of complete ST-segment resolution occurred in 138 of the 341 patients (40.5%) in the postconditioning group and 139 of the 335 patients (41.5%) in the postconditioning group. The rates were very similar and difference was not significantly different (P=0.79). Among the 323 patients who completed 4 cycles of occlusion immediately after reflow per-protocol, baseline and follow-up ECG data were available for analysis in 315 patients (97.5%) and the rate of complete ST-segment resolution was 40.6%, a rate which was similar to that of the conventional PCI group (P=0.75). PostC Conv Postconditioning Conventional PCI P Value ECG analysis 341/350 (97.4%) 335/350 (95.7%) 0.21 Time to ECG ― min 31 (29-38) 31 (29-37) 0.77 Per-protocol analysis 315/323 (97.5%) 334/349 (95.7%) 0.19

Difference (95% Confidence Interval) Postconditioning Conventional PCI Difference (95% Confidence Interval) P value n / total n (%) Age <65 87/211 (41.2%) 88/205 (42.9%) -1.7 (-11.1 to 7.7) 0.73 65 51/130 (39.2%) 0.0 (-11.7 to 11.7) 0.99 Sex   Male 105/269 (39.0%) 98/249 (39.4%) -0.3 (-8.7 to 8.0) 0.94 Female 33/72 (45.8%) 41/86 (47.7%) -1.8 (-17.0 to 13.5) 0.82 Infarct-related artery LAD 32/158 (20.3%) 28/151 (18.5%) 1.7 (-7.2 to 10.5) 0.70 Non-LAD 106/183 (57.9%) 111/184 (60.3%) -2.4 (-12.3 to 7.6) 0.64 Symptom onset-to-reperfusion time <3 hours 71/154 (46.1%) 75/153 (49.0%) -2.9 (-13.9 to 8.2) 0.61 3 hours 67/187 (35.8%) 64/181 (35.4%) 0.5 (-9.3 to 10.2) 0.93 Thrombus aspiration Yes 60/154 (39.0%) 67/170 (39.4%) -0.5 (-11.0 to 10.1) No 78/187 (41.7%) 72/165 (43.6%) -1.9 (-12.2 to 8.3) 0.72 Direct stenting 17/41 (41.5%) 19/45 (42.2%) -0.7 (-20.7 to 19.4) 0.97 121/300 (40.3$) 120/290 (41.4%) -1.1 (-8.9 to 6.9) 0.80 Glycoprotein IIb/IIIa inhibitors 35/79 (44.3%) 36/78 (46.2%) -1.9 (-17.0 to 13.4) 103/262 (39.3%) 103/257 (40.1%) -0.8 (-9.1 to 7.6) 0.86 According to the pre-specified subgroup analyses, results between the 2 groups were consistent across various subgroups. A significant or strong trend suggesting that postconditioning leads to improved ST-segment resolution was not found in any of the subgroups. -20 -15 -10 -5 5 10 15 20 Conventional PCI Better Postconditioning Better CP1089228 Rihal,CS CW 11-22-2002

Angiographic Outcomes Postconditioning (n=350) Conventional PCI P Value TIMI flow after PCI 0.08 0/1 8/349 (2.3%) 19/348 (5.5%) 2 20/349 (5.7%) 23/348 (6.6%) 3 321/349 (92.0%) 306/348 (87.9%) Myocardial blush grade after PCI 0.20 60/349 (17.2%) 78/348 (22.4%) 108/349 (30.9%) 106/348 (30.5%) 181/349 (51.9) 164348 (47.1) The postprocedural myocardial blush grade and TIMI flow grade could be assessed in 349 patients (99.7%) in the postconditioning group and 348 patients (99.4%) in the conventional PCI group. Patients in the postconditioning group tended to have a higher rate of postprocedural TIMI flow grade of 3 than those in the conventional PCI group, but statistical significance was not achieved (92.0% versus 87.9%, P=0.08). There was no significant difference in the postprocedural myocardial blush grade of 0 or 1 between the 2 groups (17.2% versus 22.4%, P=0.20). TIMI = thrombolysis in myocardial infarction.

Clinical Outcomes at 1-month Postconditioning (n=350) Conventional PCI Relative risk (95% CI)* P Value Death 13 (3.7%) 10 (2.9%) 1.30 (0.58-2.92) 0.53 Cardiac death 9 (2.6%) 1.11 (0.46-2.70) 0.82 Reinfarction 2 (0.6%) 1 (0.3%) 2.00 (0.18-21.74) 0.99† Severe heart failure 5 (1.4%) 0.40 (0.08-2.05) 0.29† Stent thrombosis 7 (2.0%) 6 (1.7%) 1.17 (0.40-3.44) 0.78 Target-vessel revascularization 3 (0.9%) 1.00 (0.20-4.92) MACE‡ 15 (4.3%) 1.15 (0.56-2.39) 0.70 Complete clinical follow-up 1-month data were obtained in all patients. No significant differences were observed between the 2 groups with regard to 1-month clinical outcomes (Table 3). Major adverse cardiac events occurred in 15 patients (4.3%) of the postconditioning group and 13 patients (3.7%) of the conventional PCI group (P=0.70). * Relative risk is for the postconditioning group as compared with the conventional PCI group. † The P value was calculated with the use of Fisher’s exact test. ‡ Major adverse cardiac event was a composite of death, reinfarction, severe heart failure, or stent thrombosis.

Outcomes according to STR, postprocedural MBG and TIMI flow grade Figure 2 Outcomes according to STR, postprocedural MBG and TIMI flow grade P<0.001 P<0.001 20 18.5% 20 18.5% Major Adverse Cardiac Events (%) 18 16.3% 18 16.3% P<0.001 16 P<0.001 16 Death (%) 14 14 10.9% 12 10.1% 12 P=0.02 10 P=0.04 10 8 8 5.3% 6 4.3% 6 2.8% 4 2.3% 4 2.4% 1.4% 1.6% 1.8% 1.7% 2 0.9% 2 ST-segment resolution, myocardial blush grade, and postprocedural TIMI flow grade were significantly associated with clinical outcomes at 1-month. Patients with complete ST-segment resolution had significantly lower rates of death and major adverse cardiac events while those with myocardial blush grades of 0 or 1 had significantly higher rates of major adverse cardiac events and death. >70 ≤70 3 2 0/1 3 2 0/1 >70 ≤70 3 2 0/1 3 2 0/1 Resolution of ST-Segment Elevation (%) Myocardial Blush Grade Postprocedural TIMI flow grade Resolution of ST-Segment Elevation (%) Myocardial Blush Grade Postprocedural TIMI flow grade

Study Limitations The sample size was inadequate to make definite conclusion on clinical outcomes. This study was not a double-blinded study. Postconditioning was not performed per protocol (4 cycles of ballooning) in about 8% of patients in the postconditioning group. ECGs before and 30 minutes after the procedure were not available in 3.5% of all patients. We excluded patients with hemodynamic instability, cardiogenic shock, or left main lesion who might have lethal reperfusion injury and receive potential benefits from postconditioning.

Conclusions In this multicenter, prospective, randomized, open-label, blinded endpoint trial, Ischemic postconditioning with primary PCI did not improve myocardial reperfusion compared with conventional primary PCI. Clinical outcomes at 1-month were not significantly different between the randomized groups. Cardioprotective effect of ischemic postconditioning was not found in any of prespecified subgroups.