Microcirculatory changes during cardiac surgery with cardiopulmonary bypass

Area of Science:

• Cardiovascular Surgery
• Intensive Care Medicine
• Microcirculation Research

Background:

• Intermediate and high mortality risk patients undergoing cardiac surgery (CS) with cardiopulmonary bypass (CPB) represent a vulnerable population.
• Assessing microcirculatory function is crucial for understanding tissue perfusion and predicting outcomes in these patients.

Purpose of the Study:

• To evaluate microcirculation in patients at intermediate and high risk for mortality undergoing CS with CPB.
• To identify potential alterations in microcirculatory parameters and their correlation with clinical outcomes.

Main Methods:

• A prospective study involving 22 patients with Euroscore >3.
• Utilized Videomicroscopy Side Stream Dark Field (SSD-BF) to assess capillary density, perfused capillaries, microcirculatory flow index (MFI), and heterogeneity flow index.
• Microcirculation was evaluated at four time points: post-anesthesia, start of CPB, end of CPB, and post-surgery.

Main Results:

• Mean arterial pressure decreased and blood lactate increased significantly from initial to final measurements.
• The microcirculatory flow index (MFI) showed a significant increase at the end of CPB and post-surgery.
• Postoperative complications were associated with significant differences in Euroscore, left ventricular ejection fraction, and MFI at the end of CPB.

Conclusions:

• Cardiac surgery with cardiopulmonary bypass in high-risk patients can lead to increased MFI and blood lactate.
• These microcirculatory changes suggest potential functional shunts at the tissue perfusion level.
• Further investigation is required to elucidate the underlying mechanisms of these observed alterations.