CHAPTER 37 



Situations which lead to changes 

 in vascular patterns 



AVE RILL A. LIEBOW 



Department of Pathology, Yale University School of Medicine, 

 New Haven, Connecticut 



CHAPTER CONTENTS 



Normally Occurring Arteriovenous Communications 



Structure 



Distribution and Size 



Development and Fate 



Function 



Role in Bodily Economy 

 Abnormal Arterial Communications 



Traumatic or Surgically Induced Arteriovenous Connections 

 Collateral Circulation 



Some Aspects of Angiogenesis in General 



Types of Collaterals 



Forces Affecting the Development of Collateral Circulation 

 Mechanical factors 

 Neural factors 

 Chemical factors 



Rate of Development 



Regression of Collaterals 



Arterial Versus Venous Collaterals 



Some Effects of Collateral Circulation 



Structure of Collateral Vessels 

 Measurement of Collateral Circulation 

 Some Outstanding Problems 



AFTER WILLIAM HARVEY HAD DISCOVERED the circu- 

 lation of the blood, there remained the mystery of its 

 transfer from arteries to veins. A solution was provided 

 by Marcello Malpighi in 1 66 1 when he first saw the 

 capillaries in the transparent lung of the frog (146). 

 It took another half century before direct connections 

 between an artery and vein (the spermatic), in this 

 instance probably anomalous, were reported by Lealis 

 Leali (43). Precapillary arteriovenous anastomoses 

 are now known to exist normally in many organs and 



tissues. Masson (117) credits Berres (14) with their 

 discovery in 1832 in erectile tissue where they were 

 later described in considerable detail by Johannes 

 Miiller (123). The transparent wing of the bat pro- 

 vided an opportunity for observing the vessels in the 

 living subject and here Paget (130) saw large arterio- 

 venous anastomoses. Hyrtl (88) noted that when these 

 structures were open there was pulsation of veins and 

 arterialization of the blood within them. Sucquet (172) 

 soon found precapillary arteriovenous connections to 

 be widely distributed in man, but his results were dis- 

 credited by such observers as Hover (80) and Berliner- 

 blau (13) for the reason that they were based on 

 injection of fluids of low viscosity. Arnold (4, 7) recog- 

 nized the "coccygeal gland," which had been dis- 

 covered by Luschka in 1859, to be analogous to the 

 glomeruli caudales of animals and to represent in 

 reality vascular complexes replete with arteriovenous 

 anastomoses. He remarked on the muscular nature of 

 some of the vessels. The first detailed histological 

 description of the specialized transitional segment was 

 by Hover (80) and this was elaborated by Grosser (65) 

 in 1902. Max Clara (29, 30), author of the most 

 extensive monographs on these structures, considered 

 Schumacher (159) to be the discoverer of the epi- 

 thelioid cells. The relationship of arteriovenous an- 

 astomoses to nerves was definitely demonstrated by 

 Masson (1 16-1 18), and was subsequently investigated 

 by Brown (25), and, with special reference to tumors, 

 by Popoff (134). 



Both normal and abnormal arteriovenous shunts 

 can exert physiological effects, but these have been 

 explored only in part. The observations of Grant (61) 



1 251 



