Myocardial protection is of crucial importance for surgical coronary revascularization in patients with ischaemic heart diseases. The investigators proposed loop isolation-based uploading preconditioning to protect heart from ischemic-reperfusion damage (LiuPhD) as a novel cardioprotective strategy, and applied to patients who underwent on-pump coronary artery bypass grafting (CABG).

Myocardial protection is of crucial importance for surgical coronary revascularization in patients with ischaemic heart diseases. Considerable effort has been made to optimize cardioprotective strategy for improving cardiac performances after global myocardial ischemia. Of various strategies, terminal warm blood cardioplegia (TWBC) delivery has been proven to be effective in reducing risk of ischemic attack at the time of myocardial reperfusion. Based on TWBC strategy and Frank-Starling law of heart, the investigators proposed loop isolation-based uploading preconditioning to protect heart from ischemic-reperfusion damage (LiuPhD) as a novel myocardial protective strategy, which procedurally renders coronary loop via brief warm blood delivery independent of extracorporeal loop following TWBC delivery just before declamping. The investigators hypothesize that LiuPhD strategy allows myocardial cells complete depolarization and drives heart into zero-loading heat cycles, contributing to enhancing myocardial physiologic reserve and improving cardiac initiative capacity responding to upcoming loading increases after onset of clamp release. The aim of the present study was to determine whether LiuPhD strategy during on-pump coronary artery bypass grafting (CABG) can attenuate reperfusion injury after global myocardial ischemia.

Inclusion Criteria:

• Patients scheduled for a first, elective, isolated, open thoracotomy, on-pump CABG were eligible for enrollment if they if they had coronary angiography-confirmed unprotected left main disease, 3-vessel disease with or without proximal LAD artery disease, or 2-vessel disease with proximal LAD artery disease.
• Inclusion criteria were evidence of preserved left ventricular function (LVEF≥35%) and normal or mild pulmonary hypertension (sPAP<50mmHg).

Exclusion Criteria:

• Exclusion criteria were secondary CABG, emergency CABG, conversion operations form off-pump CABG or minimally invasive CABG surgery, or any additional cardiac lesions necessitating concomitant surgery, as well as being considered too high risk for surgical revascularization.

The LiuPhD (Loop Isolation-based Uploading Preconditioning to Protect Heart from ischemic-reperfusion Damage) study was a prospective, open-label, single-arm, first-in-man trial on the use of LiuPhD strategy for myocardial protection in patients who underwent surgical coronary revascularization.