Phase II Clinical Trial to Evaluate the Benefits of Postconditioning in ST-Elevation Myocardial Infarction (STEMI)

• Infarct size on baseline cMRl [ Time Frame: Day 3-5 post-PCI ] [ Designated as safety issue: No ]
• Myocardial Salvage Index (MSI) on baseline cMRI [ Time Frame: Day 3-5 post-PCI ] [ Designated as safety issue: No ]
• Micro vascular Obstruction (MVO) on baseline cMRI [ Time Frame: Day 3-5 post-PCI ] [ Designated as safety issue: No ]
• Plasma levels of reactive oxidative stress chemicals: 8-isoprostane and MDA (ROS) [ Time Frame: pre and post-reperfusion ] [ Designated as safety issue: No ]

• Global Left Ventricular Ejection Fraction [ Time Frame: baseline, 3 and 12 months ] [ Designated as safety issue: No ]
• Infarct size by CK and troponin area under the curve [ Time Frame: over the first 72 hours post pci ] [ Designated as safety issue: No ]
• LV Remodeling (LVEDV, LVESV) as measured by cMRl [ Time Frame: baseline and 3 and 12 months ] [ Designated as safety issue: No ]
• Plasma and whole blood levels of chemical compounds altered by complete artery occlusion: nitrite anion and hydrogen sulfide [ Time Frame: pre and post-reperfusion ] [ Designated as safety issue: No ]

This study will evaluate change in heart muscle function from baseline to three months and twelve months in participants who present with a heart attack and a completely occluded coronary artery. These subjects will be randomized to receive standard Percutaneous transluminal coronary angioplasty (PTCA)/Stenting to open the artery or routine PTCA/Stenting plus post conditioning. Post conditioning commences immediately upon reperfusion using four cycles of thirty second inflations with a standard angioplasty balloon followed by a thirty seconds of reperfusion. The investigators hypothesize that Postconditioning reduces the size of the heart attack when utilized with successful primary Angioplasty/stent.

Single center study involving 140 patients randomized to Post Conditioning + Percutaneous coronary intervention (PCI) versus routine PCI during their ST-Elevation Myocardial Infarction (STEMI, Heart Attack) presentation. The Post Conditioning protocol consists of performing four, 30-second PTCA (Angioplasty) balloon occlusions followed by 30-seconds of reperfusion over a total of 4 minutes. The first balloon inflation occurs immediately after an angioplasty guidewire is placed through the obstruction in the artery. Following this protocol the vessel is stented as part of the usual practice for treatment of STEMI. No other treatment differences will occur between the two groups and all patients will receive the usual post-STEMI care. Patients in both groups will receive a cardiac MRI 3-5 days following their STEMI for measurement of heart attack size and heart muscle function, among other measures. Patients will undergo collection of blood for CK MB and troponin I every 8 hours for 72 hours following PCI. Blood will be collected from the arterial sheath for measurements of plasma nitrite and hydrogen sulfide levels and surrogates of reactive oxygen species (ROS) prior to reperfusion and at two timepoints following reperfusion. Patients in both groups will receive a follow-up MRI at 3 and 12 months to assess the long term effects of Post Conditioning on Heart Muscle function Heart chamber volumes (remodeling). All patients will be seen in cardiology clinic at 3 and 12 months to undergo physical exam and recording of adverse events (death, recurrent STEMI, repeat revascularization, arrhythmias and ICD placement, hospitalization for Congestive Heart Failure). All patients will be required to take clopidogrel (Plavix) and aspirin for the duration of the trial. All patients will be treated with ACEI, beta blockers and statins.

• Procedure: Post Conditioning + Primary PCI
  Four, 30-second PTCA balloon occlusions followed by 30-seconds of reperfusion over a total of 4 minutes, in addition to Percutaneous Coronary Intervention as clinically indicated.
• Procedure: Standard Primary PCI
  Routine Percutaneous Coronary Intervention as clinically indicated.

• Experimental: Post conditioning + PCI
  Intervention: Procedure: Post Conditioning + Primary PCI
• Active Comparator: Standard PCI
  Intervention: Procedure: Standard Primary PCI

Inclusion Criteria:

• Age > 18 years old, < 80 years old
• Able to give informed consent
• Able to undergo cMRl
• ST-segment elevation infarction with 100% occlusion of a major epicardial vessel (> 2.5 mm)
• No angiographic evidence of collateral flow distal to occluded artery
• Ischemic duration between 1.0 and 6 hours
• TIMI 3 Flow following PCI

Exclusion Criteria:

• Visible collateral blood flow to the distal vasculature of the occluded vessel
• Previous Coronary Artery Bypass Graft surgery
• Previous q-wave myocardial infarction in the same territory
• Inability to give informed consent
• Inability to undergo cMRl
• Life expectancy less than one year
• History of Non-compliance or alcohol or drug addiction
• Patients with cardiogenic shock, cardiac arrest, hypothermia on presentation
• Chronic dialysis or significant renal insufficiency (CrCl < 35 mI/mm/i .73 m2)
• TIMI Flow > 0 on presentation
• Ischemic Time > 6 hours or < 1.0 hours
• Presence of significant valvular heart disease (>mod AS, >2+ MR)
• Known LV systolic dysfunction (LVEF < 50% prior to STEMI)