Immediate responses of collateral vessels to abrupt arterial occlusion

¹ Department of Surgery, Beth Israel Hospital, and Harvard Medical School, Boston, Massachusetts

The vascular bed of the hamster cheek pouch was observed in vivo under the microscope as a major artery within the field was occluded. Two changes were noted: 1) an alteration in pattern of blood flow and 2) the opening of previously unseen branches on each side of the ligature. Both responses were immediate and persisting. Besides providing for new flow patterns, the newly opened arterial branches preserve additional length of the ligated artery which becomes obliterated on each side of the ligature to the nearest open branch. Comparison of in vivo with postmortem observations indicated that latent and open branches of the artery under observation were about equal in number, and that about half of the latent branches opened in response to the ligation. Induced vasoconstriction delayed the opening of latent branches, cold prevented it. Priscoline opened all latent vessels, with or without arterial ligation. In connection with Burton's data on "critical closing pressure" of fine vessels, the ligation of a large artery appears to establish a "critical opening pressure" within latent branches.

Key Words: collateral arterial circulation • latent vessels • small vessel critical opening pressure • effect of drugs on latent vessels • effect of temperature on latent vessels

Submitted on November 15, 1963