Chapter 72: Abdominal Vascular Injuries October 24, 2005

Abdominal trauma zones

Trauma algorithms

Damage control procedures Persistent attempts to reconstruct or repair all abdominal injuries may result in increased mortality ‘damage control’ approach All complex venous injuries are ligated Arterial injuries may be shunted Any diffuse retroperitoneal or parenchymal bleeding is controlled by tight gauze packing

Abdominal compartment syndrome Normal pressure resting supine is near zero Elevation of pressure above 25 to 30 cm of water may cause severe organ dysfunction Abdominal compartment syndrome characterized by Tense abdomen Tachycardia with or without hypotension Respiratory dysfunction with high peak inspiratory pressures Oliguria Risk factors Massive blood transfusions Prolonged hypotension Hypothermia Aortic cross clamping Damage control procedures Tight closure of abdominal wall

Abdominal compartment syndrome High risk patients can be followed with clinical exam and serial bladder pressure measurements Pressures greater than 30 indicate need for surgical decompression of abdomen Temporary abdominal wall closure can be performed with large dialysis bag or synthetic mesh When bowel edema improves several days later the abdomen can be closed

Abdominal aortic injuries Blunt injury is rare 0.04% of all blunt trauma admissions Intimal dissections and thrombosis most common lesions Penetrating trauma more likely 2.7% of gunshot wounds to abdomen 1.5% of knife wounds to abdomen 21% of all abdominal vascular injuries, second most commonly injured vascular structure

Abdominal aortic injuries Operative exposure by medial visceral rotation

Celiac artery injuries Rare, 302 cases of vascular injury, the celiac artery was involved in 3.3% of cases Operative exposure through lesser sac or medial visceral rotation, this does not need to include the left kidney Ligation is tolerated well secondary to rich collateral blood supply Mortality ranges from 38 to 75%, probably secondary other concominant injuries

SMA injuries Zone 1 aortic origin to inferior pancreaticoduodenal artery Zone 2 to the middle colic artery Zone 3 distal to middle colic artery Zone 4 segmental intestinal branches Ligation of SMA in zones 1 and 2 results in severe ischemia of small bowel and right colon Ligation of SMA in zones 3 and 4 may result in localized ischemia

SMA injuries Penetrating injuries are the most common mechanism of injury SMA injuries diagnosed in 0.09% of trauma admissions and account for 10% of all abdominal vascular injuries, Asensio Am J Surg. Blunt trauma responsible for 10 to 20% of these injuries

SMA injuries Any hematoma injury involving bowel ischemia should be explored Author does not explore stable hematomas if the bowel is not compromised, they are followed post-operatively by angiography or doppler ultrasound Sharp partial transections can be managed by lateral arteriorrhaphy in 40% of cases Mobilization of SMA made difficult by surrounding dense neuroganglionic tissue and multiple branches, thus end to end anastomosis rarely possible Ligation of SMA below middle colic artery associated with moderate risk of bowel ischemia

SMA injuries Ligation of SMA proximally only in the presence of necrotic bowel, otherwise may result in short bowel syndrome In critical ill patients with hypothermia, acidosis, and coagulopathy a damage control procedure with a temporary endoluminal shunt may be performed Later reconstruction may be performed with saphenous vein or PTFE from the aorta, if there is any associated pancreatic injury all attempts should be made to keep the anastomosis away from the pancreas and should be protected by omentum and soft tissue Some authors mandate a second look operation in 24 hours, others look for persistent metabolic acidosis despite adequate fluid hydration

SMA injuries Reported mortality with SMA injuries varies from 33 to 68% in multiple series This is difficult to assess as patient typically have multiple other associated injuries

IMA injuries Rare and almost always due to penetrating traumas, 1% of all abdominal vascular injuries Ligation is well tolerated with no cases of colorectal ischemia have been reported in trauma

Iliac vascular injuries Low reported incidence from WW2, Korean war and Vietnam war, 1.7 to 2.6% Urban trauma centers report 10% of all abdominal vascular injuries for both arteries and veins 26% have combined injures Penetrating trauma involves common iliac vessels Blunt usually involves branches of internal iliac artery Also pelvic fractures can directly tear iliac vessels or result in stretching of the vessel resulting in intimal tear and subsequent thrombosis

Iliac vascular injuries Blunt trauma explore if Intraperitoneal leak Expanding hematoma Absent or dimished femoral pulse Penetrating trauma should be explored Ureter should be identified and protected Avoid iatrogenic injuries to underlying vein Isolation and control of internal iliac artery important even proximal and distal control is present If exposure is difficult an additional transverse lower abdominal incision or longitudinal groin incision can be made

Iliac vascular injuries Small arterial injuries can be repaired with 4-0 and 5-0 sutures Venous or PTFE patch can be used to avoid stenosis With most gunshot wounds and blunt trauma, reconstruction by an end to end anastomosis can be undertaken size 6 to 8mm Balloon tipped catheter should be passed proximally and distally to remove clots Author recommends local heparin, role for systemic heparin? Author suggests no significant role for extraanatomic bypasses in trauma Burch (Trauma 1990) suggests that enteric spillage is not a contraindication to prosthetic graft

Iliac vascular injuries Ligation of the common or external iliacs a bad choice Instead a temporary intraluminal shunt should be used Author believe transection of the right common iliac artery to gain better access to the iliac veins is “extreme and should rarely be considered.” Instead careful mobilization and retraction of the artery should be performed Ligation and division of the internal iliac artery may also be helpful Ligation of an iliac vein is preferable to a repair that causes stenosis that can lead to thrombosis and pulmonary embolism Role of filters in narrowed iliac veins yet to be determined Patient tend to develop transient leg ischemia

Iliac vascular injuries Many patients develop compartment syndrome of their extremities and require fasciotomies Role of prophylactic fasciotomies controversial If fasciotomy is not performed, close clincal examination and pressure measurements are warranted Mannitol may be useful to reduce effects of reperfusion injury and inhibiting the development of compartment syndrome

Renovascular injuries 16% of all abdominal vascular injuries Left renal artery 1.3 to 1.6 times more likely to be injured than right renal artery, thought to be due to its course underneath IVC 50% of cases of blunt arterial injury result in intimal tears and subsequent arterial thrombosis 12% of cases involve avulsion 9 to 14% of cases involve both arteries When possible abdominal CT scan a very good diagnostic tool

Renovascular injuries For penetrating injuries generally reconstruction or nephrectomy is performed depending on extent of injury All zone 2 hematomas secondary to penetrating injury should be explored Blunt trauma is very time dependent Renal function severly affected after three hours of total ischemia and six hours after partial ischemia More aggressive approaches to those with bilateral injuries or those with injuries to a solitary kidney, some authors have attempted revascularization up to 20 hours after initial injury Cumulative success of revascularization is 28% with subsequent hypertension developing in 12 to 58% of patients 32 to 40% of patient managed non-operatively develop renovascular hypertension

Renovascular injuries Ligation of the left renal vein well tolerated near IVC because of drainage through left gonadal vein, left adrenal vein and lumbar veins Ligation of the right renal vein should be followed by nephrectomy Endovascular techniques useful to treat selected cases of intimal tears, false aneurysms, and AV fistulas

IVC injuries Most commonly injured abdominal vessel accounting for 25% of all injuries Blunt trauma account for 10% of these injuries and typically retrohepatic With penetrating injuries also 18% of patients have associated aortic injury All hematomas secondary to penetrating trauma should be explored, except for stable retrohepatic hematomas Infrarenal/juxtarenal IVC best exposed by medial rotation of the right colon, hepatic flexure of colon, and duodenum Exposure of retrohepatic IVC by dividing ligaments, extending incision to include right subcostal Median sternotomy if atriocaval shunt is planned

IVC injuries Hepatic vascular isolation Atriocaval shunt Cross clamping infradiagphragmatic aorta, suprahepatic IVC, infrahepatic IVC above renals, and portal triad Failure to clamp aorta first may result in severe hypotension and then cardiac arrest due to reduced venous return Atriocaval shunt Typically with poor results but some case reports describe some successes

IVC injuries Liver can be divided along gallbladder IVC plane to provide direct exposure Most IVC injuries repaired with 3-0/4-0 prolene Cava can be rotated to expose posterior injuries With anterior and posterior injuries, the posterior injury can be repaired through the anterior injury (can also be lenghtened) Ligation can be considered above the renal veins in very unstable patients or those with significant stenosis after repair Post-op patient should have lower extremities wrapped in firm elastic bandages and elevated, edema usually subsides in several weeks Patients may develop compartment syndrome and require fasciotomies

IVC injuries Mortality Half of patients with IVC injuries die before reaching the hospital Those reaching the hospital have reported survival rates of 20 to 57% Kuene (Am Surg, 1999) reported an overall mortality of 52%, the mortality decreased to 35% if the patient reached the operating room Associated higher mortality with suprarenal injuries

Portal vein system injuries Injury is very rare, about 1% of those patients undergoing laparotomy for trauma About 5% of abdominal vascular injuries SMV injuries about 11% and splenic vein about 4% of abdominal vascular injuries Majority of portal vein injuries secondary to penetrating trauma 90% Associated vascular injuries reported to be high, 70 to 90% due to anatomy

Portal vein system injuries Blunt trauma usually involves SMV and direct blow to abdomen or deceleration forces Results in thrombosis of vessels and sometimes avulsion and bleeding With isolated thrombosis, diagnosis made on CT scan Stapled division of the pancreatic neck should be considered early Suprapancreatic portal vein exposure by medial rotation of right colon and hepatic flexure and a Kocher maneuver

Portal vein system injuries Portal vein injuries should be repaired with lateral venorrhaphy Complex reconstructions often fail and only undertaken if hepatic artery is out Ligation of both hepatic artery and portal vein is not compatible with life, in this case reconstruction of the portal vein should be undertaken with saphenous vein Ligation of the portal vein with an open hepatic artery survival ranges from 55 to 85% Patients with ligated SMV or portal veins will need further attention Bowel will become massively edematous resulting in abdominal compartment syndrome, thus the abdomen should not be closed Can develop patch bowel wall necrosis and a re-look operation should be performed in 48 to 72 hours Patients require massive fluid replacement Long term evidence is limited but survivors do not develop portal hypertension

Portal vein system injuries Mortality is high and ranges between 50% to 72%

Advances Introduction of the policy of scoop and run in addition to early surgical control of bleeding is now standard of care Concept of damage control Recognition of abdominal compartment syndrome and use of temporary prosthetic Endovascular techniques to specific vascular occlusions, av fistulas and false aneurysms