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Functional assessment of collaterals in the human coronary circulation
C Seiler1, M Fleisch, S F de Marchi
1Cardiology, University Hospital, Berne, Switzerland. christian.seiler@insel.ch
Insights
Accurate assessment of coronary collateral circulation is now possible using new guidewire technologies. These methods provide functional data, advancing research into heart blood supply and treatment strategies.
Area of Science:
- Cardiovascular Physiology
- Interventional Cardiology
Background:
- Coronary collateral circulation provides alternative blood supply to jeopardized myocardium.
- Traditional assessment methods (e.g., angina history, ECG, angiography) are qualitative or semiquantitative.
- Accurate functional assessment of coronary collateral circulation was previously limited.
Purpose of the Study:
- To review clinically available methods for functional characterization of coronary collateral circulation.
- To highlight advancements in assessing collateral blood flow in humans.
Main Methods:
- Utilizing coronary wedge pressure measurements during balloon occlusion.
- Employing ultrathin pressure and Doppler angioplasty guidewires for pressure/flow velocity data.
- Calculating functional variables for coronary collateral flow, expressed as a fraction of antegrade flow.
Main Results:
- New guidewire technologies enable accurate measurement of coronary collateral flow indices.
- Pressure- and flow velocity-derived parameters are interchangeable and validated.
- These methods allow for functional characterization previously limited to experimental studies.
Conclusions:
- Clinically available methods now permit accurate functional assessment of coronary collateral circulation.
- Advancements open new avenues for investigating collateral circulation's pathogenesis and pathophysiology.
- Therapeutic promotion of collateral circulation can be further explored using these functional indices.
Abstract:
The coronary collateral circulation is an alternative source of blood supply to a myocardial area jeopardized by the failure of the stenotic or occluded vessel to provide enough blood flow to this region. Until recently, only qualitative or semiqualitative methods have been available for the assessment of the coronary collateral circulation in humans, such as the patient's history of walk-through angina pectoris, the registration of intracoronary ECG signs for myocardial ischaemia or angina pectoris during coronary occlusion, or coronary angiographic classification (score 0-3) of collaterals. Studies of coronary wedge pressure measurements distal of a balloon-occluded coronary artery and the recent advent of ultrathin pressure and Doppler angioplasty guidewires have made it possible to obtain pressure or flow velocity data in remote vascular areas and, thus, to calculate functional variables for coronary collateral flow. Those coronary occlusive pressure- and flow velocity-derived parameters express collateral flow as a fraction of antegrade coronary flow during vessel patency of the collateral-receiving vessel. They are both interchangeable, and they have been validated in comparison to 'traditional' methods and against each other. The possibility of accurately measuring coronary collateral flow indices in humans undergoing coronary balloon angioplasty opens areas of investigation of the pathogenesis, pathophysiology and therapeutic promotion of the collateral circulation previously reserved for exclusively experimental studies. The purpose of this article is to review several clinically available methods for the functional characterization of the coronary collateral circulation.