Warm heart surgery: experience with long cross-clamp times

Area of Science:

• Cardiovascular Surgery
• Cardiothoracic Anesthesia
• Myocardial Protection

Background:

• Hypothermic cardioplegic arrest reduces myocardial oxygen demand but relies on anaerobic metabolism and causes hypothermia-related injury.
• Current methods limit safe aortic occlusion to 120 minutes due to compromised myocardial protection.
• Electromechanical arrest accounts for 90% of myocardial oxygen consumption, suggesting alternative strategies are needed.

Purpose of the Study:

• To evaluate the safety and efficacy of warm aerobic arrest for myocardial protection.
• To assess the feasibility of prolonged aortic occlusion times using warm aerobic arrest.
• To compare outcomes of warm aerobic arrest with traditional hypothermic methods in high-risk patients.

Main Methods:

• A prospective application of warm aerobic arrest in 308 consecutive cardiac procedures.
• Retrospective review of 22 high-risk patients with aortic cross-clamp times ≥ 3 hours (mean 204 minutes).
• Assessment of spontaneous rhythm, weaning from bypass, and need for inotropic support.

Main Results:

• All hearts resumed spontaneous sinus rhythm without defibrillation.
• 21 out of 22 patients were weaned from bypass easily without additional support.
• Low rates of mortality (4.5%) and low-output syndrome (4.5%), with no perioperative myocardial infarctions.

Conclusions:

• Warm aerobic arrest is a safe and effective myocardial protection strategy for prolonged, high-risk cardiac surgeries.
• This method virtually eliminates ischemia, limits reperfusion injury, and avoids hypothermia-related detrimental effects.
• Warm aerobic arrest facilitates successful outcomes in complex cardiac procedures exceeding traditional safety limits.