Vascular graft selection

Twenty to thirty per cent of patients with arterial injuries and some patients with venous injuries require interpositional grafting. The first choice of grafting material for both arterial and venous injuries is autogenous vein. Injuries to large vessels such as the aorta and superior vena cava may necessitate synthetic prostheses. Synthetic aortic prostheses have excellent long-term patency rates, but the same materials are much less likely to remain patent in the vena cava. Panel or spiral grafts constructed from saphenous vein appear to be the best replacement for this vessel. Autogenous veins are present in different diameters ranging from a mean of 6.4 mm in the saphenous vein to a mean of 1.8 cm in the internal jugular vein. The thickest autogenous vein is the saphenous vein, and thus it is preferred for medium-sized and small arteries. The authors prefer the larger 7.5-mm cephalic vein for replacement of medium-sized veins. In the absence of suitable saphenous vein, the cephalic vein is also the choice for arterial interposition grafts. Although there are few reports of the use of arterial autografts in vascular trauma, the surgeon should be aware that autografts may be ideal for vascular injuries in children and for isolated injuries with severe contamination. Finally, the use of synthetic grafts in injuries where adequate tissue coverage is not possible may result in immediate limb salvage, but the incidence of limb loss in this situation will be extremely high.

Thoracic great vessel injury

Thoracic great vessel injury may be secondary to blunt, penetrating, blast, or iatrogenic trauma. A surgeon should be the initial evaluator of and decision maker for these patients, and the aortogram remains the gold standard for specific diagnosis of the arterial injuries except in those patients requiring emergency thoracotomy. Two general types of incisions are employed for these injuries: resuscitative and elective.

Central venous catheter stiffness and its relation to vascular perforation

Delayed central venous perforation is an uncommon but serious complication of central venous catheter insertion. An increase in catheter stiffness may have been responsible for our association of venous perforation with use of a guidewire insertion technique. A bench model was used to investigate the stiffness characteristics of thirty-four different types of catheters. The initial stiffness is poorly described by material or catheter gauge. A large range of values is seen between apparently similar catheters--the 16 gauge polyethylene catheter associated with two perforations at our institution had an initial stiffness value 7.5 Nm2 X 10(-5) at 37 degrees C in comparison with our previous standard--the 16 gauge Deseret Intracath with an initial stiffness of 2 Nm2 X 10(-5). Multilumen catheters had a similar range of stiffness to single lumen catheters, while paediatric catheters in general were less stiff. Dialysis catheters were up to five times as stiff as the stiffest central venous catheter. Stiffness decayed at a rate and to an extent which differed from catheter to catheter. Absorption of water by the catheter appears to be one factor involved in stress relaxation.

Diagnostic evaluation of extremity vascular injuries

Diagnostic evaluation of patients with possible vascular injuries presents the physician with a number of circumstantial impediments that may limit the applicability of clinical signs and symptoms, noninvasive testing, and angiography. The challenge is to know these limitations and learn to work around them while still applying clinical skills, noninvasive tests, and angiography when appropriate and feasible and to the limits of their worth, rather than to resort to either routine angiography or blind exploration in every case.

Abdominal vascular injuries

Abdominal vascular injuries remain rare in centers that primarily treat victims of blunt trauma, but when penetrating wounds of the abdomen are commonly treated, the incidence of abdominal vascular injuries is surprisingly high. With suitable management, many of these patients survive.

Upper-extremity vascular injuries

Although upper-extremity injuries alone are usually not life-threatening, they can produce significant immediate or long-term morbidity, especially if there is an associated nerve injury. The diagnosis of an arterial injury may be readily apparent, but the excellent upper-extremity collateral circulation may create palpable distal pulses despite a significant proximal arterial injury. Therefore, a high index of suspicion and the liberal use of arteriography are necessary to avoid missing these injuries. Compression of the brachial plexus by a hematoma can produce a serious neurologic deficit. Prompt evacuation of the hematoma may significantly reduce the deficit, another fact that supports an aggressive surgical approach in these patients. The long-term results of upper-extremity vascular injuries are usually determined by the extent of any associated nerve injuries.

Traumatic internal mammary arteriovenous fistula. A case report and review of the literature

A rare case of arteriovenous fistula of the right mammary artery following penetrating chest wound is reported. The patient was treated one week later because of right-sided hemothorax associated with diastolic machinary murmur. Selective digital subtraction angiography showed a fistulous communication connecting the right internal mammary vessels. The fistula was cured through a right anterolateral thoracotomy. The surgical literature is reviewed.

Inadvertent catheterization of the internal thoracic vein mimicking pulmonary embolism: a case report

Although aberrant locations are typical complications of central venous catheterization, the right internal thoracic vein (mammary vein) is an exceptional one. A case of this unusual aberrant location occurring after right internal jugular venous cannulation for total parenteral nutrition, is described. This aberrant position caused signs and symptoms resembling pulmonary embolism. This is the first known description of the symptoms induced by the infusion of parenteral solution into the right internal thoracic vein.

Thromboembolic reaction following wall puncture in arterioles and venules of the rabbit mesentery

The walls of rabbit mesenteric arterioles and venules (diameter 20 to 40 microns) were punctured with glass micropipets (tip diameter 6 to 8 microns). Thromboembolic reactions resulting from this standardized, small mechanical vessel wall injury could be quantified in vivo with the use of intravital video-microscopy. Following induction of the injury thrombus growth started immediately (less than 0.1 s). Bleeding times were short, on the average less than 2 s, and did not differ between arterioles and venules. The duration of the embolization process was significantly longer in arterioles than in venules (median 101 and 17 s, respectively), and more emboli were produced in arterioles than in venules (median 6 and 1, respectively). Arteriolar thrombi were more effective in plugging the punctured holes than venular thrombi. The differences in thromboembolic reaction between arterioles and venules, as found in the present study, can probably not be explained by fluid dynamic factors.

Long-term results with autogenous tissue repair of traumatic extremity vascular injuries

With extensive vascular injuries in which a vascular conduit is required, there is controversy as to whether an autogenous or prosthetic graft is preferable. The authors reviewed their experience with 91 extremity arterial injuries in which autogenous tissue was used to repair vascular injuries of the extremities. Twenty-two patients also had concomitant repair of associated venous injuries with autogenous vein grafts. Ten patients required amputations, despite patent grafts in five patients, because of severe muscle necrosis. Two patients had thrombosis of their vein grafts develop in the early postoperative period but did not require amputation. The authors identified only one late vein graft failure in a patient in whom an infected pseudoaneurysm developed. Three patients with extensive soft tissue injuries had infection develop in vein grafts, with subsequent massive bleeding that ultimately required arterial ligation. Among the 22 patients with repair of their venous injuries, occlusion of popliteal vein repairs was documented in two patients and suspected in three others. The remainder of patients had satisfactory results. The excellent results obtained in the vast majority of the authors' patients with extremity vascular injuries reinforces their preference for using autogenous tissue whenever a vascular conduit is required. Exceptions include patients with extensive soft tissue loss precluding adequate graft coverage, the repair of large vessels, and life-threatening emergencies when there is insufficient time to harvest and prepare a vein.

A decade of lower extremity venous trauma: patency and outcome

Eighty-two patients with infrailiac venous injuries were reviewed. Veins were repaired in 75 patients and ligated in 7 patients. Clinical outcome could be correlated with anatomic patency for 41 patients who had postoperative venograms. Sixty-three percent of the repairs proved to be patent. Simple repairs were successful more often than complex ones. Site of injury and perioperative therapeutic adjuncts did not affect results. Eleven limbs were amputated, none solely because of venous injury. Edema was present at last follow-up in fewer patients with patent repairs than occluded repairs or ligations. Repair of major lower extremity venous injuries should be attempted routinely in stable patients. Improved patency of complex repairs may require increased use of balloon catheter thrombectomy and other adjunctive procedures. Postoperative venography is very useful for the evaluation of results.

Incomplete biochemical adaptation of vein grafts to the arterial environment in terms of prostacyclin production

Biochemical (or functional) adaptation of venoarterial grafts has been demonstrated recently. We reexamined one aspect of this biochemical "arterialization" process: prostacyclin (PGI2) production by canine venoarterial autologous grafts and the responsiveness of this biosynthetic pathway to maximal stimulation with substrate enhancement. Four reversed autologous grafts (femoral vein) were interposed into both carotid and femoral arteries in eight dogs. After 12 weeks, the grafts were removed, and radioimmunoassay was used to determine luminal surface production of 6-keto-PGF1 alpha (the stable metabolite of PGI2) in both the basal and stimulated (27 mumol/L arachidonic acid [AA]) states. PGI2 production by the venous autologous grafts was compared with that of control native artery and vein. We confirmed that PGI2 production (measured in nanograms per milliliter) by control artery was greater than vein under both basal conditions (5.8 +/- 0.4 [+/- SEM] vs. 2.7 +/- 0.5, p less than 0.001) and stimulated conditions (8.8 +/- 0.8 vs. 5.5 +/- 0.4, p = 0.002); moreover, AA stimulation significantly increased PGI2 production in both native artery and vein compared with basal PGI2 production. Under basal conditions, graft PGI2 production (6.3 +/- 1.6 ng/ml) was not significantly different than basal arterial levels (p = 0.8) but was higher than basal venous levels (p = 0.05). However, in marked contrast to both native artery and vein, the vein graft flow surface showed no significant response to substrate enhancement with AA: basal (6.3 +/- 1.6 ng/ml) vs. stimulated (5.9 +/- 0.9 ng/ml) (p = 0.8). These observations confirm that canine venoarterial autologous grafts undergo biochemical "arterialization"; however, this process appears to be an incomplete one.(ABSTRACT TRUNCATED AT 250 WORDS)

The tide is stemmed. A method of catheter traction for the control of venous haemorrhage following transurethral resection of prostate

Local pressure for the control of venous haemorrhage during the performance of surgery is the primary method of control of bleeding when ligation is technically impossible. A method of catheter traction for the control of profuse bladder neck venous haemorrhage is described.