Interaction of compliant coronary stenoses in series in a XXXX model.

@entity235 @entity3979 @entity850
Resistance and flow across compliant coronary stenoses may be altered by changes in intraluminal pressure. The effects of a distal circumflex @entity3979 on a proximal compliant circumflex @entity850 were evaluated in 17 open-chest @entity235 . In ten @entity235 , both stenoses were produced with external snares. As the distal @entity850 was tightened, a point was reached at which flow through the circumflex coronary artery paradoxically increased (8 +/- 1 to 11 +/- 1 ml/min; p less than 0.001). At the point of flow increase, there was an increase in intraluminal pressure between the stenoses (35 +/- 4 to 61 +/- 5 mmHg; p less than 0.001), and a decrease in pressure gradient (69 +/- 5 to 43 +/- 4 mmHg; p less than 0.001) and resistance (10.5 +/- 2.7 to 4.7 +/- 0.8 units; p less than 0.025) across the proximal @entity850 . A similar increase in circumflex blood flow was found in @entity235 in which the @entity850 was produced with an intraluminal balloon. In six additional @entity235 in which the proximal @entity850 was produced with fixed noncompliant plastic tubing, tightening the distal snare did not result in an increase in circumflex blood flow. Thus, the increase in flow occurred only when the proximal @entity850 was compliant. Increasing the severity of the distal @entity850 caused an increase in intraluminal pressure in the area of the proximal @entity850 and may have passively distended the compliant proximal @entity850 decreasing its severity. Therefore, in the presence of compliant coronary stenoses in series, increasing severity of the distal @entity850 may cause a paradoxical increase in flow through the stenotic artery.
