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Regional ischemic preconditioning enhances myocardial performance in off-pump coronary artery bypass grafting
Jari Laurikka1, Zhong-Kai Wu, Pekka Iisalo
1Department of Surgery, Tampere University Hospital, Tampere, Finland.
Insights
Ischemic preconditioning (IP) improved heart function after off-pump coronary artery bypass grafting (CABG). This safe procedure enhanced stroke volume recovery and reduced heart rate increases post-surgery.
Area of Science:
- Cardiology
- Cardiac Surgery
- Ischemic Physiology
Background:
- Off-pump coronary artery bypass grafting (CABG) is a surgical procedure to improve blood flow to the heart.
- Myocardial stunning can occur during CABG, potentially impacting cardiac performance.
- Ischemic preconditioning (IP) is a phenomenon where brief episodes of ischemia protect the heart.
Purpose of the Study:
- To investigate the effects of ischemic preconditioning (IP) on myocardial performance in patients undergoing off-pump CABG.
- To determine if IP can mitigate myocardial stunning and improve postoperative cardiac function.
Main Methods:
- A randomized, controlled, prospective study involving 32 patients undergoing off-pump CABG.
- Patients were divided into an IP group and a control group.
- IP was induced by two 2-minute occlusions of the left anterior descending artery (LAD) with 3-minute reperfusion periods before grafting.
Main Results:
- Ischemic preconditioning (IP) led to complete recovery of stroke volume index (SVI) post-surgery, unlike the control group (p=0.039).
- IP patients showed a significantly lower increase in heart rate (HR) on postoperative day 1 and reduced cardiac troponin I (CTnI) levels (p=0.043).
- No increase in mechanical ventilation duration, ICU stay, or inotropic medication use was observed in the IP group.
Conclusions:
- Two cycles of regional ischemic preconditioning (IP) in the LAD are safe and applicable for off-pump myocardial revascularization.
- IP demonstrated a trend towards decreased immediate myocardial enzyme release.
- The protocol prohibited postoperative HR increase and enhanced SVI recovery.
Objectives:
We intended to investigate whether ischemic preconditioning (IP) enhances myocardial performance in patients who undergo off-pump coronary artery bypass grafting (CABG).
Design:
A controlled, randomized, prospective study.
Setting:
A university hospital.
Patients:
Thirty-two patients with left anterior descending coronary artery (LAD) or two-vessel heart disease (including LAD) who were to undergo off-pump CABG were randomized into an IP group and a control group.
Interventions:
IP was induced by occluding the LAD twice for a 2-min period followed by 3-min LAD reperfusion before bypass grafting of the first coronary vessel.
Measurements And Results:
Registration included hemodynamic data from the peripheral artery and the pulmonary artery, and the measurement of cardiac troponin I (CTnI) and creatine kinase isoenzyme MB (CK-MB) values. IP resulted in a complete recovery of the mean stroke volume index (SVI) after the operation. In the control subjects, the mean SVI showed a significant reduction postoperatively (p = 0.039). On the first postoperative day, the increase in the mean heart rate (HR) was also significantly lower in the IP patients. The CTnI level was statistically significantly lower in the IP group (p = 0.043), and IP patients tended to have a smaller CK-MB release after surgery (not significant). The duration of mechanical ventilation, the length of stay in the ICU, and the use of inotropic medication did not increase after the IP protocol.
Conclusions:
Two cycles of regional 2-min IP in the LAD, followed by 3 min of reperfusion, proved to be applicable and safe in patients undergoing off-pump myocardial revascularization, it tended to decrease the immediate myocardial enzyme release, it prohibited the postoperative increase in HR, and it enhanced the recovery of SVI.