Modulation of left ventricular diastolic distensibility by collateral flow recruitment during balloon coronary occlusion.
OBJECTIVE
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.
Remah
H A
HA
Second Department of Internal Medicine, Toyama Medical and Pharmaceutical University, Japan.
Asanoi
H
H
Joho
S
S
Igawa
A
A
Kameyama
T
T
Nozawa
T
T
Inoue
H
H
D000368:Aged; D000369:Aged, 80 and over; D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects; D003097:Collateral Circulation; D003326:Coronary Circulation; D003971:Diastole; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000209:etiology / Q000503:physiopathology; D013318:Stroke Volume; D016277:Ventricular Function, Left