Emergency Vascular Surgery A Practical Guide - part 8

140 Chapter 11 Vascular Access in Trauma Further Reading Klofas E. A quicker saphenous vein cutdown and a bet-ter way to teach it. J Trauma 1997; 43:985–987 Waisman M, Waisman D. Bone marrow infusion in adults. J Trauma 1997; 42:288–293 Fig.11.1. Cutdown and exposure of a vein in the cubi-tal fossa for acute venous access Complications in Vascular Surgery 12 CONTENTS 12.1 Summary ...........................142 12.2 Background ........................142 12.2.1 Magnitude of the Problem .........142 12.3 IschemicComplications ...........142 12.3.1 Pathophysiology ...................142 12.3.2 Clinical Presentation ...............144 12.3.2.1 Graft Occlusion in the Leg ..........144 12.3.2.2 Ischemia After Aneurysm Operations and Endovascular Procedures .........................144 12.3.3 Diagnostics .........................145 12.3.3.1 Leg Ischemia ........................145 12.3.3.2 VisceralIschemia ...................145 12.3.4 Management and Treatment .......146 12.3.4.1 Management in the Emergency Department, ICU, and the Ward ....146 12.3.4.2 Operation .......................... 147 12.3.4.3 Management After the Operation 147 12.3.5 Results and Outcome .............. 147 12.3.5.1 Graft Occlusion ..................... 147 12.3.5.2 Ischemia After AAA Surgery and Endovascular Procedures ......148 12.4 BleedingComplications ...........148 12.4.1 Causes ..............................148 12.4.2 Clinical Presentation ...............148 12.4.2.1 MedicalHistory. . . . . . . . . . . . . . . . . . . . . 148 12.4.2.2 Physical Examination ...............149 12.4.3 Diagnostics .........................149 12.4.4 Management and Treatment .......149 12.4.4.1 In the Emergency Department, ICU, or Surgical Ward ...............149 12.4.4.2 Operation ..........................150 12.4.4.3 Management After Treatment ..... 151 12.5 Infections .......................... 151 12.5.1 Pathophysiology .................... 151 12.5.1.1 Types of Infection .................. 151 12.5.1.2 Microbiology .......................152 12.5.1.3 Pathophysiology ...................152 12.5.2 Clinical Presentation ...............152 12.5.2.1 MedicalHistory. . . . . . . . . . . . . . . . . . . . . 152 12.5.2.2 Physical Examination ...............152 12.5.2.3 LaboratoryTests ................... 153 12.5.3 Diagnostics ......................... 153 12.5.3.1 Aortic Graft Infection ............... 153 12.5.4 Management and Treatment .......154 12.5.4.1 In the Emergency Department .....154 12.5.4.2 Operation .......................... 155 12.5.4.3 Management After Treatment ..... 155 12.5.5 Results and Outcome ..............156 12.6 LocalComplications ...............156 12.6.1 Lymphocele and Seroma ...........156 12.6.1.1 Background and Causes ............156 12.6.1.2 Clinical Presentation ...............156 12.6.1.3 Management and Treatment .......156 12.6.2 Postoperative Leg Swelling ........157 12.6.2.1 Background and Causes ............157 12.6.2.2 Clinical Presentation ...............157 12.6.2.3 Management and Treatment .......157 12.6.3 Wound Edge Necrosis ..............157 12.6.3.1 Background and Causes ............157 12.6.3.2 Clinical Presentation ................157 12.6.3.3 Management and Treatment .......157 12.6.4 Local Nerve Injuries ................157 12.6.4.1 Background and Causes ............157 12.6.4.2 Clinical Presentation ...............158 12.6.4.3 Management and Treatment .......158 Further Reading ...................158 142 Chapter 12 Complications in Vascular Surgery 12.1 Summary Wound infections may cause life-threaten-ing bleeding by eroding an anastomosis. An infected surgical wound overlying a vascular reconstruction should not be de-brided in the emergency department. A patient with an aortic graft admitted for gastrointestinal bleeding should be treated as having an aortoduodenal fistula. Vascular graft infection should be suspect-ed in a patient with unspecific symptoms and a previously implanted aortic graft. Leg ischemia following thrombotic occlu-sion of a previous vascular reconstruction requires careful consideration before a de-cision to operate, unless the extremity is immediately threatened. Suspected extremity or visceral ischemic complications after aortic procedures should be managed in close cooperation with an experienced vascular surgeon. 12.2 Background The most common complications of vascular sur-gery – myocardial infarction, aggravated angina, renal insufficiency, and pulmonary problems – will not be dealt with in this chapter. Such system-ic complications are consequences of the medical background of vascular surgical patients. In fact, most patients have general manifestations of arte-riosclerosis, diabetes, and chronic obstructive pul-monary disease. These risk factors also contribute to the higher incidence of specific complications in this patient group after vascular as well as gen-eral surgical procedures. The specific complica-tions of vascular surgical procedures can be cate-gorized into four groups: 1. Ischemic, caused by thrombosis, embolization, dissection, and occlusion of vessels 2. Bleeding 3. Infection in wounds and grafts 4. Local complications in the surgical field. In this chapter complications will be discussed under headings corresponding to these catego-ries. 12.2.1 Magnitude of the Problem The number of complications is related to the number of vascular surgical procedures per-formed. In Sweden, for instance, the number of operations increased from approximately 500 per million inhabitants per year in 1982 to almost 1,200 per million in 1995. A similar pattern is common for most Western countries. The number of procedures, especially endovascular, has con-tinued to rise, and one-third of registered proce-dures are classified as reoperations. The latter cov-ers revisions of anastomotic problems, angioplasty of restenosis and graft stenosis, operations for acute bleeding, and extirpation of infected grafts. The incidence of postoperative complications can be estimated from these Swedish data. If ap-proximately 12,000 operations are performed yearly and the risk of complications requiring a visit to the clinic is estimated to be 20%, 2,400 pa-tients will seek medical attention for a complica-tion following a vascular procedure (Table 12.1). In Sweden this corresponds to six or seven patients daily. Most doctors on call will meet such patients and manage their initial work-up and treatment. 12.3 Ischemic Complications 12.3.1 Pathophysiology Ischemic complications after vascular operations are common and influence several organ systems. Examples of such complications are listed in Table 12.2. There are many different causes and some-times several factors contribute simultaneously. The consequence is ischemic symptoms in the affected organ. Vascular reconstructions for chronic leg isch-emia have a high risk for developing graft occlu-sion, especially in the first years after the primary operation. Up to half of the grafts will eventually occlude. The causes for occlusion vary depending on when it occurs. Early (within 30 postoperative days), technical causes dominate, such as a badly sutured anastomosis, intimal tear, and intact valve cusps in an in situ bypass. Other examples are poor vein graft quality and extensive arteriosclero-sis in run-off arteries. Late graft occlusion is sec-ondary to intimal hyperplasia in the graft or the 12.3 Ischemic Complications 143 Table12.1. Frequency of complications after vascular procedures Category Ischemia Bleeding Infection Type of initial procedure/location Suprainguinal Infrainguinal Diagnostic angiography Aortic surgery Aortic surgery All types of proce-dures Wound Aortic graft Femoropopliteal bypass Complication rate of all interventions 15% 20–60% 0.5% 4–5% 1% 1–3% 8–20% 1–3% 2–5% Comment Includes endovascular as well as open procedures Graft occlusions only (varies with the level of the distal anastomosis – more distal = higher risk) Includes symptomatic embolization Renal insufficiency only (higher risk after operations for rupture) Intestinal ischemia only after elective surgery (after surgery for rupture, up to 8%) Bleeding requiring reoperation After inguinal incisions with antibiotic prophylaxis After surgery for aneurysms as well as occlusive disease Synthetic grafts only. Considerably lower for vein grafts Table12.2. Ischemic complications after vascular interventions (PTA percutaneous transluminal angioplasty, AAA abdominal aortic aneurysm) Symptomatic organ Leg and foot Leg and foot, intestine, kidneys Kidneys Colon Leg and foot, intestine Original procedure Bypass Aneurysms, PTA AAA (ruptured) AAA (ruptured) PTA, all vascular operations Mechanism Graft occlusion Embolization Clamping, hypovolemia Clamping Dissection Time when it occurs Early and late Early Early Early (late) Early Main cause Technical errors, intimal hyperplasia Dislodged thrombus Impaired renal perfusion Ligation of inferior mesenteric artery Intimal dissection causes vascular occlusion anastomotic area. Early graft occlusions are gener-ally easier to treat and have a better prognosis. Embolization and dissection complicates mainly percutaneous transluminal angioplasty (PTA) and angiography. The catheters can dislodge a throm-bus located in the abdominal or thoracic aorta that follows the bloodstream to the mesenteric or renal arteries or down into lower extremity vessels. Vig- orous manipulation of the aneurysm during sur-gery for abdominal aortic aneurysms (AAAs) might also cause embolization. This may result in “trash foot,” a specific type of acute leg ischemia affecting the foot rather than the entire leg. The name comes from the consequence – that the foot will end up as “trash.” It is caused by numerous small emboli occluding distal foot arteries. 144 Chapter 12 Complications in Vascular Surgery Dissection, as a complication of angiography or angioplasty, may also cause ischemia. This might happen anywhere an artery was catheterized, but usually in the aorta. The bloodstream then sepa-rates the layers in the vascular wall, creating two separate lumina with blood flow. Most damage occurs when the orifices of the intestinal and renal arteries are occluded by the dissection and these organs become ischemic. This is further described in Chapter 8. Another type of ischemic complication is mul-tifactorial and follows aortic surgery, usually after emergency operations in which hypovolemic shock is common. Arterial clamping, poor perfu-sion due to hypovolemia, and hypotension may cause renal failure and ischemic colitis of the sig-moid colon. Reperfusion injury after declamping makes the ischemic consequences worse. Renal in-sufficiency evolves within 1 week of the operation, but a decrease in urine production is seen imme-diately after the procedure. Intestinal ischemia usually has an early onset because of postoperative hemodynamic problems but might also be delayed. As soon as the intestinal perfusion is below the critical limit damage will occur. 12.3.2 Clinical Presentation 12.3.2.1 Graft Occlusion in the Leg Reappearance of preoperative symptoms is the main reason why patients seek help. Often this is worsened claudication, rest pain, or new ulcer-ations, and the patient describes a sudden onset of symptoms that have deteriorated rapidly. The time of onset coincides with the moment when the graft occludes. It is important to note the time when a venous graft occludes because the endo-thelium is destroyed within 8–10 h. First appear-ance of severe problems is regularly preceded by a period of some deterioration, which is caused by a developing stenosis. It is important to gather as much information as possible about the original operation, the way the graft was tunneled, problems that occurred during the operation (such as poor quality of the vein graft, iatrogenic injuries, problems with in-flow), and the result of follow-up examinations. General risk factors also need to be considered if reoperation or thrombolysis is probable. The physical examination aims to establish the graft occlusion, determining the severity of isch-emia and the level of occlusion. This is accom-plished by inspecting the foot and leg and by pulse palpation. Furthermore, the ankle-brachial index (ABI) is measured to objectively grade the isch-emia. Palpation of pulses along the graft is also helpful to elucidate whether the graft is patent, but interpretation is sometimes difficult. An in situ graft may have pulsations in its proximal parts but be occluded distally with outflow into a residual vein branch. The graft can also be patent despite occlusion of the recipient artery when blood flows in the outflow artery in a retrograde direction. Some grafts are difficult to palpate because they are tunneled deep along the occluded artery. Syn-thetic grafts are also hard to examine, and a pen Doppler can then identify the graft for palpation. The Doppler signal must also be interpreted with care. The signal may emanate from flow in veins or smaller arteries, so its presence does not guar-antee graft patency. Generally, the medical history and physical ex-amination are sufficient to diagnose the ischemia and if there are no pulses along the graft this sug-gests occlusion or obstruction. When the examin-er is in doubt a duplex examination is performed. 12.3.2.2 Ischemia After Aneurysm Operations and Endovascular Procedures These complications are discovered in the post-operative period. A patient in the ward who has undergone endovascular treatment and suddenly starts to complain of abdominal pain, a cold pain-ful leg, or more unspecific symptoms should be suspected to be suffering from embolization. The symptoms vary with the vascular segment that has been obstructed. If the superior mesenteric artery is affected, symptoms are similar to those of acute intestinal ischemia (Chapter 6, p. 67). Abdominal pain may also be caused by renal infarction. If a large artery to a lower extremity is occluded, the symptoms are the ones described in Chapter 10 on acute leg ischemia (page 121). The medical history obtained should include information about the procedure, including whether any problems occurred. For AAA proce-dures it is important to know if the AAA treated involved the suprarenal or juxtarenal area, if it ... - tailieumienphi.vn