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Quantitating coronary collateral flow velocity in patients during coronary angioplasty using a Doppler guidewire
M J Kern1, T J Donohue, R G Bach
1Cardiology Division, St. Louis University Hospital, Missouri 63110.
Insights
Quantifying coronary collateral flow in patients using a Doppler-tipped guidewire revealed mean collateral flow velocity was 30% of normal antegrade flow. Pharmacologic agents did not increase flow, but mechanical stimulation did, offering new insights into coronary collateral circulation.
Area of Science:
- Cardiovascular Medicine
- Interventional Cardiology
- Hemodynamics
Background:
- Coronary collateral flow quantitation in patients has historically relied on angiographic methods with inherent limitations.
- Assessing collateral circulation is crucial for understanding myocardial perfusion in occlusive coronary artery disease.
Purpose of the Study:
- To quantitatively measure coronary collateral flow velocity in patients with occluded vessels using a novel Doppler-tipped guidewire.
- To investigate the response of collateral flow to pharmacologic and mechanical stimuli.
Main Methods:
- Utilized a Doppler-tipped angioplasty guidewire to measure antegrade and retrograde flow velocity in 17 patients with totally or subtotally occluded coronary vessels.
- Quantitated mean collateral flow velocity and analyzed its phasic pattern.
- Assessed collateral flow response to intracoronary nitroglycerin, adenosine, and mechanical balloon occlusion.
Main Results:
- Mean collateral flow velocity was approximately 30% of normal postangioplasty antegrade flow velocity.
- Retrograde diastolic and systolic flow velocity integrals were 20% and 40% of post-procedure antegrade flow velocity, respectively.
- Intracoronary nitroglycerin and adenosine did not significantly increase collateral flow, whereas mechanical balloon occlusion markedly augmented it.
Conclusions:
- The Doppler-tipped guidewire provides a quantitative method for assessing coronary collateral flow in humans.
- Coronary collateral flow is variably modulated, with mechanical stimulation showing a greater augmentation effect than common pharmacologic agents.
- These findings represent initial quantitative observations and pave the way for future research into factors influencing collateral circulation and myocardial ischemia.
Abstract:
Quantitation of coronary collateral flow in patients has been limited to angiographic techniques, which are subject to well-known methodologic limitations. The use of a Doppler-tipped angioplasty guidewire permits measurement of both antegrade and retrograde flow distal to totally or subtotally occluded vessels that may be supplied with acutely recruitable or angiographically mature collateral conduits. Using coronary flow velocity as an indicator of collateral flow, retrograde flow velocity was quantitated in 17 patients. Mean collateral flow velocity was approximately 30% of normal postangioplasty antegrade flow velocity. The phasic pattern of collateral flow was highly variable, but the retrograde diastolic and systolic flow velocity integrals were 20% and 40% (respectively) of post-procedure antegrade flow velocity. Preliminary studies with pharmacologic stimulation of the contralateral supply artery suggests that collateral flow is not increased by intracoronary nitroglycerin (200 micrograms) or adenosine (12 micrograms), but may be markedly augmented during mechanical stimulation of balloon occlusion. These data represent the first in a series of quantitative observations on control of the coronary collateral circulation in humans. Future investigations using the Doppler Flowire (Cardiometrics) will enhance understanding of factors modulating ischemia through collateral supply.