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[Concept of critical stenosis in cardial surgery]
1Moscow Medical Academy im. I.M. Sechenova, Bloshaya Pirogovskaya, Moscow, Russia.
Insights
Critical stenosis, a universal concept in arterial circulation, signifies a severe narrowing (around 75%) where blood flow drastically drops, necessitating collateral circulation for tissue survival. This principle aids bypass surgeries and explains conditions like mitral stenosis.
Area of Science:
- Cardiovascular Science
- Vascular Surgery
- Clinical Medicine
Background:
- Severe arterial stenosis (approx. 75% lumen reduction) leads to abrupt distal blood flow cessation, making the region dependent on collateral circulation.
- This phenomenon is exemplified in coronary artery bypass grafting, allowing temporary artery clamping without cardiopulmonary bypass.
- Mitral stenosis also demonstrates a critical orifice area (1 cm2) triggering decompensation.
Discussion:
- The concept of 'critical stenosis' applies universally across the arterial system.
- It highlights the threshold at which collateral circulation becomes essential for maintaining tissue perfusion.
- Understanding critical stenosis is vital for surgical planning and managing vascular diseases.
Key Insights:
- A critical stenosis threshold exists for large arteries, impacting distal blood flow and survival.
- Collateral pathways are crucial for tissue viability when native inflow is severely compromised.
- This principle is clinically applicable in procedures like coronary artery bypass grafting and understanding valvular stenosis.
Outlook:
- Further research can refine critical stenosis thresholds for various arterial beds.
- Investigating the role and efficiency of collateral networks in different patient populations.
- Exploring novel therapeutic strategies targeting collateral development or managing critical stenosis.
Abstract:
When stenosis of a large artery reaches about 75% of its lumen blood flow distal to obstruction abruptly falls and ceases to play decisive role for the region it supplies. This region survives due to opening of collaterals. This allows to cross-clamp coronary artery for 20-30 minutes and to create distal anastomosis during aorto-coronary venous or mammary coronary artery bypass grafting without artificial circulation. Another example is mitral stenosis. There exists a critical value of an orifice area (1 cm2 or 25% of the lumen) when abrupt decompensation develops. Similar cut off values of inflow (nourishing) vessel stenoses can be demonstrated in other regions of cardiovascular system. Thus conception of a 'critical stenosis' is universal for the arterial part of circulation and finds wide application in clinical practice.