Objective:

To summarize the physiology of microcirculation and examine the mechanisms by which cardiopulmonary bypass (CPB) impairs microvascular function, highlighting its significance in postoperative outcomes, as well as to review current tools for microcirculatory assessment and cardioprotective strategies.

Key Findings:

• CPB is associated with significant microvascular dysfunction despite normal macro-hemodynamic stability, impacting postoperative recovery.
• Endothelial glycocalyx shedding occurs rapidly during ischemia-reperfusion, leading to microvascular instability and potential organ dysfunction.
• Clinical evidence for cardioprotective strategies remains heterogeneous and often relies on indirect measures of organ dysfunction, indicating a need for more direct assessments.

Interpretation:

There are important gaps in translating findings from experimental models to clinical practice, particularly in understanding the mechanisms of microcirculatory dysfunction, and greater integration of imaging and biomarkers with biophysiological principles is needed.

Limitations:

• Technical challenges limit the clinical use of microcirculatory assessment tools, necessitating advancements in technology.
• Lack of standardized endpoints for assessing microcirculatory function hinders comparability across studies.

Conclusion:

Focusing on microcirculation may provide new pathways to improve outcomes in cardiac surgery, emphasizing the need for targeted strategies in clinical practice.