Related Experiment Videos
Differential characterization of human coronary collateral blood flow velocity
C Tron1, T J Donohue, R G Bach
1Department of Internal Medicine, St. Louis University, MO, USA.
Insights
This study quantifies coronary collateral blood flow velocity in patients during angioplasty, revealing predominantly systolic flow and distinct patterns. These findings offer new insights into assessing interventions on collateral circulation.
Area of Science:
- Cardiovascular Physiology
- Interventional Cardiology
Background:
- The protective role of coronary collateral circulation is known, but its phasic nature and velocity in patients remain understudied.
- Understanding collateral flow dynamics is crucial for evaluating its functional significance during interventions.
Purpose of the Study:
- To characterize and quantify ipsilateral coronary collateral blood flow velocity in patients undergoing coronary angioplasty.
- To define patterns of collateral flow (phasic, monophasic, bidirectional) and their relationship to anatomic pathways and angiographic grading.
Main Methods:
- Coronary collateral flow velocity was measured using a Doppler-tipped guidewire in 49 patients during balloon occlusion.
- Collateral filling was graded using the Rentrop scale, and pathways were classified (epicardial, intramyocardial, acutely recruited).
- Flow patterns were analyzed for systolic/diastolic components and directionality.
Main Results:
- Three distinct collateral flow patterns were identified: biphasic (47%), monophasic (35%), and bidirectional (18%).
- Predominantly systolic flow was observed in 73% of patients.
- Epicardial collateral pathways exhibited the highest total flow velocity integral compared to intramyocardial and acutely recruitable pathways.
Conclusions:
- Coronary collateral blood flow exhibits distinct phasic patterns, with a majority occurring during systole.
- Flow velocity measurements provide a novel method for assessing interventions on human collateral circulation.
- Rentrop grading did not correlate with flow velocity integrals, suggesting velocity measurement offers complementary information.
Abstract:
The functional importance and protective nature of the coronary collateral circulation has been well established. There are few data, however, regarding the phasic nature and absolute velocities of collateral flow in patients. The aim of this study was to characterize and quantify ipsilateral coronary collateral blood flow velocity in patients during coronary angioplasty. Coronary collateral flow velocity was measured in 49 patients during coronary angioplasty. Angiographic collateral filling was categorized by the Rentrop grading scale (0 to 3) and by anatomic pathway (epicardial, intramyocardial, or unknown [acutely recruited]). Collateral blood flow velocity was measured with a Doppler-tipped guide wire placed distal to the balloon occlusion in the collateralized vessel. Collateral flow velocity was characterized as predominantly systolic or diastolic, and phasic flow patterns were defined as biphasic (both systolic and diastolic), monophasic (only systolic or diastolic), or bidirectional (antegrade and retrograde velocity). Twenty-three (47%) patients had biphasic flow; 17 (35%) patients had monophasic flow; and 9 (18%) patients had bidirectional flow. Thirty-six (73%) of 49 patients had predominantly systolic flow signals. Epicardial collateral pathways had the highest total flow velocity integral, at 15.0 +/- 7.0 (vs intramyocardial [8.4 +/- 5.7] and acutely recruitable [5.4 +/- 2.1]; p < 0.05). There were no differences in flow velocity integrals among the Rentrop angiographic grades of collateral filling. These data establish three patterns of coronary collateral blood flow and demonstrate that the majority of collateral flow in the ipsllateral receiving vessel occurs during systole. The measurement of coronary collateral flow velocity provides a unique means to study the effects of pharmacologic or mechanical interventions on human collateral blood flow.