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Modulation of left ventricular diastolic distensibility by collateral flow recruitment during balloon coronary
1Second Department of Internal Medicine, Toyama Medical and Pharmaceutical University, Japan.
Insights
Coronary collateral flow significantly impacts left ventricular (LV) distensibility during balloon coronary occlusion (BCO). Good collateral flow maintains LV distensibility, while poor flow leads to detrimental pressure changes.
Area of Science:
- Cardiology
- Physiology
- Medical Imaging
Background:
- Left ventricular (LV) distensibility is crucial for acute dilation post-myocardial infarction.
- Human responses of LV diastolic pressure-volume (P-V) relations to coronary occlusion are inconsistent.
Purpose of the Study:
- To investigate the scaffolding effect of coronary vasculature.
- To determine the role of collateral flow in modulating LV distensibility during balloon coronary occlusion (BCO).
Main Methods:
- Serial LV pressure-volume (P-V) loops were obtained from 16 patients undergoing percutaneous transluminal coronary angioplasty.
- Coronary collateral flow was assessed angiographically during BCO.
Main Results:
- Poor collateral flow (grades 0-I) shifted diastolic P-V relations downward and rightward, increasing end-diastolic volume (EDV) without significant end-diastolic pressure (EDP) change.
- Good collateral flow (grades II-III) shifted diastolic P-V relations upward and rightward, increasing minimal pressure (min-P), EDP, and EDV.
- Reactive hyperemia post-deflation rapidly shifted P-V relations upward, particularly in poor collateral flow patients.
Conclusions:
- Coronary filling grades (retrograde or anterograde) directly influence LV distensibility.
- The scaffolding effect of coronary vascular turgor rapidly modulates LV distensibility.
Objectives:
The goals of this study were to elucidate the scaffolding effect of blood-filled coronary vasculature and to determine the functional role of recruited collateral flow in modulating left ventricular (LV) distensibility during balloon coronary occlusion (BCO).
Background:
Although LV distensibility is an important factor affecting acute dilation after myocardial infarction, the response of LV diastolic pressure-volume (P-V) relations to coronary occlusion is inconsistent in humans.
Methods:
Micromanometer and conductance derived LV P-V loops were serially obtained from 16 patients undergoing percutaneous transluminal coronary angioplasty. Coronary collateral flow recruitment was angiographically evaluated by contralateral and ipsilateral contrast injection during BCO.
Results:
In the group with poor collateral flow (grades 0-I; n = 8), BCO resulted in a downward and rightward shift of the diastolic P-V relations, where end-diastolic volume (EDV) increased by 13% (p < 0.05) without appreciable change in end-diastolic pressure (EDP; 18 +/- 6 to 18 +/- 8 mm Hg). In contrast, BCO in the group with good collateral flow (grades II-III; n = 8) shifted the diastolic P-V relations upward to the right with a concomitant increase in minimal pressure (min-P; 6 +/- 4 to 10 +/- 5 mm Hg, p < 0.05), EDP (15 +/- 7 to 21 +/- 9 mm Hg, p < 0.05) and EDV (+/- 10%, p < 0.05). Reactive hyperemia after balloon deflation caused a rapid and parallel upward shift of the diastolic P-V relations with a marked increase in min-P and EDP, especially in the group with poor collateral flow, before any improvement in LV contraction or relaxation abnormalities.
Conclusions:
Grades of coronary filling, either retrograde or anterograde, abruptly modulate LV distensibility through the rapid scaffolding effect of coronary vascular turgor.