Penetrating arteriovenous fistulas: Uncommon and challenging entities

Penetrating arteriovenous fistulas (AVFs) are a rare complication of vascular injuries; consequently, few trauma surgeons and trauma centers have significant experience with their management. Most series have been reported during wartime and/or prior to the advent of well-developed vascular surgical techniques and instruments.

Penetrating injuries may involve both the arteries and veins in close proximity, resulting in an anomalous connection between the two vessels—otherwise defined as an AVF. Clinical presentation of these injuries may vary from asymptomatic to exsanguinating hemorrhage. AVFs are a well-reported but very rare complication of penetrating injuries. An AVF is essentially a shunt, with flow from the high arterial pressure system to the low venous pressure system bypassing the high resistance arterioles. As such, there is an increased volume of right-sided venous return to the heart, thus by the Starling mechanism, the stretch reflex causes the heart to increase contractility. This increased stroke volume work imposed upon the heart may result in high-output heart failure (HF) on a long-term basis.

Antyllus (150 bc ), a Greek surgeon, was credited by Sir William Osler for the early description of an AVF and its differentiation from an aneurysm via the characteristic, pulsating “thrill.” Osler also credits Galen, with the first successful treatment of an AVF with the application of a “viscid, conglutinable and obstructive dressing.” William Hunter, in 1757, provided the first description of the physiology of AVFs, while Annandale, in 1875, described the first successful surgical management of a popliteal AVF.

Many wars have transpired since Antyllus’s original description with the management of vascular injuries advancing significantly. Rich reported 262 AVFs following penetrating trauma from 509 combat casualties and identified 7500 vascular injuries from the Vietnam Vascular Registry for an incidence of 0.3%. The mortality for these injuries in this series was 1.8% with surgical repairs performed on all patients. Soubbotich in 1913 strongly recommended that AVFs “be operated on as they had no prospects for spontaneous resolution.” Shumacker, in 1950, reported 245 AVFs, 5 (2%) of which healed spontaneously and within 3 months of the original injury. This observation was also made by Billings in 1973 who reported the spontaneous resolution of an axillary AVF in a 19-year-old marine wounded in Vietnam with multiple fragments. Similarly, Rich described two other patients wounded in Vietnam with spontaneous AVF resolution treated at Walter Reed General Hospital. Thus, surgical intervention remains a requirement for the majority of these patients. With current advances in endovascular surgery, a new and effective weapon has been added to the surgical armamentarium. The objectives of this chapter are to review their incidence, clinical presentation, radiologic identification, management, complications, and outcomes and to provide a review of exposures and surgical techniques for their management.

Mechanism of injury

Data were available in all 291 patients describing their mechanism of injury. The most common mechanism of injury was stab wounds (126 [49%]), followed by gunshot wounds (94 [37%]), miscellaneous etiologies (35 [12%]), and penetrating injuries with an unspecified agent (36 [12.4%]). Examples of miscellaneous mechanisms of injury include penetrating small iron tip, shrapnel, glass shards, and a barb of a stingray (see Table 1 ).

TABLE 1

Mechanism of Injury Resulting in AVF Secondary to Penetrating Trauma Stratified to Anatomic Zone (n = 291)

	n	SW	GSW	Misc.	Penetrating unspecified
Neck	69	34	21	6	8
Thorax	46	26	9	9	2
Abdomen and pelvis	87	46	28	4	9
Extremities	89	20	36	16	17
Total	291	126 (43.3%)	94 (32.3%)	35 (12.0%)	36 (12.4%)

AVF, Arteriovenous fistula; SW, stab wound; GSW, gunshot wound; Misc., miscellaneous.

Data regarding mechanism of injury was stratified according to anatomic region neck (69 [24%]), thorax (46 [16%]), abdomen and pelvis (87 [30%]), as well as upper and lower extremities (89 [30%]). The upper and lower extremities were the most common anatomic regions harboring AVFs secondary to penetrating injuries, with stab wounds being the most common mechanism of injury for all anatomic regions except the extremities, where gunshot wounds predominated: 36 gunshot wounds (50%) versus 20 stab wounds (28%) ( Figs. 1–3 ).