Surgical treatment of chronic abdominal ischemia

The study includes data of 139 patients with chronic abdominal ischemia, due to hemodynamically significant occlusion of impaired visceral aortic branches. The diagnosis was confirmed by aortography, computed tomoangiography and duplex color angioscanning. Immediate and long-term results of 49 reconstructive and conditionally reconstructive operations, 11 transcutaneous endovascular angioplasty, as well as postoperative complications, were analyzed.     

Colon ischemia accompanying ruptured abdominal aortic aneurysm

Myocardial, cerebral, and renal ischemia are recognized as serious sequelae in patients surviving repair of ruptured abdominal aortic aneurysms. Colonic ischemia, though a documented consequence of aortic reconstruction, has received less emphasis in these patients. In a 5-year review of a single hospital's experience, 50 patients underwent an emergency operation for ruptured abdominal aortic aneurysm. Ninety-six percent of the patients were in shock preoperatively. Of the 37 patients who survived the initial surgical procedure, 12 (32%) were subsequently found to have colon ischemia diagnosed by proctoscopy, repeat laparotomy, or autopsy. Among 20 of the initial survivors who later died at intervals up to 6 weeks after aneurysm repair 8 (40%) had colon ischemia as the sole or major contributing cause of death. Because of the high incidence of this serious but remediable problem in patients undergoing emergency operation for ruptured abdominal aortic aneurysm, we now routinely perform: (a) intraoperative Doppler examination of the colonic arterial tree, with consideration of mesenteric revascularization if necessary, (b) daily postoperative sigmoidoscopy and examination of the stool for blood, and (c) aggressive “second-look” laparotomy in patients exhibiting any signs or symptoms suggesting colonic infarction. Our experience suggests that large bowel infarction is a common, lethal, and underemphasized complication following successful repair of ruptured abdominal aortic aneurysms.     

Spinal ischemia following abdominal aortic surgery.

Serious spinal cord ischemia may follow infrarenal abdominal aortic surgery. Five cases are summarized and added to the 23 previously published cases in order to identify this syndrome, emphasize its importance, and draw attention to the possibility of spontaneous recovery which may occur. The multifactorial complex which comprises each patient's clinical picture clouds a precise and specific cause for paraplegia in these cases. However, neither hypotension, steal phenomena nor emboli are necessary for completion of the syndrome. The relevant spinal cord arterial anatomy indicates that the common anomalies which occur favor development of spinal cord ischemia in the arteriosclerotic population which requires aortic surgery. No means of prevention is possible at this time.     

Intestinal ischemia complicating abdominal aortic surgery.

A 9-year experience with 2137 patients undergoing infrarenal abdominal aortic reconstruction was reviewed to determine both the incidence of intestinal ischemia and the clinical, anatomic, and technical factors associated with this complication of aortic surgery. A total of 24 (1.1%) patients had overt intestinal ischemia, documented by reoperation or endoscopic findings. Of these, colon ischemia occurred in 19 (0.9%) and small bowel ischemia developed in 5 (0.2%) patients. The incidence after elective operation for aneurysmal or occlusive disease did not differ, but patients with ruptured aneurysms and those undergoing reoperative procedures for total graft replacement were at higher risk. Preoperative angiography was most helpful in ascertaining risk. Ligation of a patent inferior mesenteric artery was the most common (74%) feature in patients with colon ischemia. With preexisting inferior mesenteric artery occlusion, impairment of collateral circulation was attributable to superior mesenteric artery disease, dissection or retractor injury, prior colon resection, or exclusion of hypogastric perfusion. Bloody diarrhea was the most frequent postoperative symptom and colonoscopy the most reliable means of diagnosis. One half of patients with colon ischemia required resection after late recognition of perforation. All cases of small bowel ischemia were related to superior mesenteric artery disease or injury or use of suprarenal clamping. The overall mortality rate was 25% but rose to 50% if bowel resection was required. Intestinal ischemia remains an infrequent but serious complication of aortic surgery. Despite a multifactorial cause, identification of patients at increased risk can lead to operative strategies to reduce its occurrence.     

Aortic dissection with ischemia of the abdominal organs

Abdominal organ ischemia associated with aortic dissection is a serious problem, although its incidence is not so high. In particular, the prognosis of bowel ischemia is extremely poor, especially, in cases with the diagnosis delayed and with extensive bowel ischemia. Consequently, 1st it should be suspected, in cases with abdominal pain or distension associated with acute or chronic aortic dissection. Then, its pathology should be assessed quickly with enhanced computed tomography (CT) or ultrasound examination to clarify the mechanism of critical organ ischemia including dynamic obstruction or static obstruction of the visceral arteries. According to the mechanism of abdominal organ ischemia, the best treatment of catheter interventions such as catheter fenestration, endovascular aortic repair, and branch-stenting, or of conventional open surgery such as surgical abdominal aortic fenestration, graft replacement, and branch-bypass should be appropriately chosen without delay.     

腹主动脉阻断导致内脏缺血再灌注损伤的研究

目的观察腹主动脉阻断所引起的肝、肾、小肠等内脏缺血再灌注损伤的改变。方法建立小猪腹主动脉阻断１小时的模型,检测在不同再灌注时点组织及血液中丙二醛（ＭＤＡ）和超氧化物歧化酶（ＳＯＤ）的变化,同时检测肝肾功能和动脉血气分析,观察动物术后的生存情况。结果与缺血前比较,大多数再灌注时点血、组织中ＭＤＡ明显升高,而ＳＯＤ明显降低（Ｐ＜０．０５）。在再灌注２小时,血中谷丙转氨酶（ＡＬＴ）、尿素氮（ＢＵＮ）、肌酐（ＣＲＥ）较缺血前明显升高（Ｐ＜０．０１）,代谢性酸中毒也极为明显。多数动物术后能够存活,但均出现下肢截瘫。结论腹主动脉阻断１小时能引起明显的内脏缺血再灌注损伤改变,多数内脏经处理后其损伤能够得到代偿恢复,而脊髓损伤恢复困难。     

Results of surgical treatment of chronic abdominal ischemia]

The immediate results of surgical treatment for chronic abdominal ischemia were studied in 112 patients. The late-term results were studied in follow-up periods of 6 months to 20 years in 105 (95.5%) patients treated by operation and in 45 patients who were not operated on. In the immediate postoperative period, positive results were recorded in 104 (92.8%), no changes were found in 4 (3.6%) patients, and fatal outcomes occurred in 4 cases (3.6%). In the late-term postoperative period the results were positive in 79 (75.2%) patients, no changes were produced in 3 (2.9%), the disease recurred in 21 (20%) patients, and 2 (1.9%) patients died. Actuarial analysis showed the late-term results of surgical treatment to be higher by 40.8% in a 5-year follow-up period and by 27.7% in a 10-year follow-up period (69.93 +/- 5.8% in a 5-year period and 36.69 +/- 9.43% in a 10-year period) than in nonoperative treatment (29.16 +/- 6.75% and 8.97 +/- 4.27%, respectively) in P less than 0.01.     

Colon ischemia following abdominal aortic aneurysm repair in the era of endovascular abdominal aortic repair

OBJECTIVE: To review, in the era of endovascular abdominal aortic repair (EVAR), the clinical spectrum of colonic ischemia (CI) following abdominal aortic aneurysm (AAA) repair and to assess the rate, overall mortality, and associated factors of occurrence. METHODS: Between 1995 and 2005, 1174 patients with infrarenal AAA were treated either by open surgery (n = 682) or by EVAR (n = 492). Preoperative risk factors, clinical presentation, intraoperative data, and early postoperative outcomes were prospectively assessed. Overt colonic ischemia as proven by colonoscopy and/or by operation was considered as a validating event and was correlated to collected variables. RESULTS: CI occurred in 34 patients (2.9%). Eighteen out of 34 (53%) patients died within 1 month. At 2 years, the survival rate was 35% in the CI group vs 86% in the non-CI group. Associated factors of occurrence of CI were: type of operation (open group = 27/682 [4%] vs EVAR = 7/492 [1.4%] [P = .01]), aneurysm rupture (11/88 [12.5%] vs 23/1086 [2.1%], P < .001), preoperative renal insufficiency (4/30 [13.3%] vs 29/1133 [3.1%], P = .01), preoperative respiratory insufficiency (8/157 [7%] vs 23/1005 [2%], P = .01), duration of operation (<2 hours [518] = 1.7%, between 2 to 4 hours [558] 2.9%, more than 4 hours [66] 13.6%, P = .001). Mean blood loss was greater in patients with CI (CI = 2000 ml [650-3350] than in those without CI = 1000 ml [500-1800] P = .008). Logistic regression analysis showed that rupture (OR 6.03 [interval of confidence (IC) 95% 2.68-13.5] P = .0001), duration of operation (OR 5.73 [IC 95% 2.06-15.9] P = .001) and creatinin > 200 mol/l (OR 4.67 [IC 95% 1.39-15.7] P = .028) were independent factors of CI. The mortality due to colonic ischemia was not statistically different between open surgery 14/27 (52%) and EVAR 4/7 (57%). CONCLUSION: CI remains a serious complication following AAA repair. In the univariate analysis, EVAR was associated with a lower rate of colonic ischemia. However, the logistic regression analysis showed that only rupture, long duration of operation, and prior renal disease were independently associated with CI. Within the two treatment modalities, the mortality rate remained identical.     

Ischemic colitis and mesenteric ischemia after abdominal aortic reconstruction

Ischemic colitis is quite a rare condition, which can be subdivided into two categories, a so-called occlusive form as a complication of various vascular diseases, and a non-occlusive form caused by exogenous administration of drugs, or i.e. higher cocentrations of various endotoxines or cytokines. Besides the most serious cases with transmural ischemia, needing operation and resection, over 50% of all cases suffer from non-transmural or mucosal ischemia which can be treated conservatively. These cases usually show a rather favourable outcome. A part of these patients will suffer from bowel stenosis or strictures later on and may need secondary resections. Ischemic colitis following aorto-iliac reconstructive surgery is a rare but well known complication. Although it should be suspected much more frequently, only 1 to 2% of the patients will present a condition of clinical importance. The complication is more frequent in patients who undergo surgery as an emergency, especially reconstruction for aneurysmal disease, and it is less frequent in patients who undergo aorto-iliac reconstruction for occlusive disease; probably because the latter have already developed collateral vessels in the visceral area. A preoperative evaluation of this specific risk is rarely possible by angiography. Intraoperative strong pulsating backflow from the inferior mesenteric artery is considered as a quite reliable prognostic factor for a sufficient mesenteric circulation. Measurement of inferior mesenteric stump pressure, fluoresceine instillation and doppler ultrasound have been proposed as more reliable predictive elements. Wherever mesenteric circulation seems to be doubtful, inferior mesenteric replantation is advisable. In the postoperative course, a thorough clinical surveillance and probably systematic sigmoidoscopy especially on patients with prolonged intubation in strongly advisable in order to detect ischemic lesions in an early stage. Early operations on transmural lesions will help to improve this otherwise very serious and life threatening complication.     

Leg ischemia following surgery for abdominal aortic aneurysm.

Resection of an abdominal aortic aneurysm was associated with intraoperative or postoperative leg ischemia in seven of 100 consecutive survivors of this procedure. Distal embolization of thrombus and debris is the apparent cause in the majority of cases (six). One case of stenosis at a graft-to-vessel anastomosis was identified. Early (intraoperative) thromboembolectomy averted tissue loss in four cases. The role of concurrent lumbar sympathectomy in ameliorating ischemic tissue loss is evaluated. Postaneurysmectomy leg ischemia may accompany other serious complications, particularly hypotension and renal failure.     

Spinal cord ischemia following operations on the abdominal aorta

Spinal cord ischemia following operations on the abdominal aorta is considered an unpredictable event attributable to variations in spinal cord blood supply. Our experience with seven cases of spinal cord ischemia contradicts this hypothesis. All patients had a bifurcation graft implanted. Three patients had bilateral interruption of hypogastric circulation. Each had gluteal necrosis and two had left colon ischemia. Two patients had unilateral hypogastric ligation. In both of these patients, early postoperative hypotension preceded recognition of spinal cord ischemia. Two patients without known interruption of hypogastric flow had proximal side-to-end anastomoses placed in an atheromatous aorta. Intraoperative peripheral emboli occurred in one and postoperative visceral emboli occurred in the other patient. In the latter case spinal cord ischemia occurred late concomitantly with embolization. The surmised important details in patients' courses with spinal cord ischemia are (1) interference with pelvic blood flow (five of seven patients) severe enough in three cases to cause gluteal necrosis and (2) a high incidence of perioperative complications. Interruption of an anomalous spinal artery was probably not a factor as cord lesions were mostly distal and no case of spinal cord ischemia occurred after a cylinder graft was placed. Spinal cord ischemia is potentially preventable. Our experience reemphasizes the importance of hypogastric perfusion, the dangers of handling the atheromatous aorta, and the necessity for avoiding postoperative hypotension.     

Perioperative predictors of colonic ischemia after ruptured abdominal aortic aneurysm

Purpose: Colonic ischemia and colonic resection occur frequently after ruptured abdominal aortic aneurysm (rAAA). The purpose of this study was to identify the perioperative risk factors that might help to determine earlier in the postoperative period which patients are at risk for colonic ischemia and colonic resection. Methods: The medical records of the 43 patients who underwent repair of rAAA from January 1989 to November 1997 were reviewed. The data were reviewed for the following factors: acidosis, pressor agents, lactate levels, guaiac status, cardiac index, coagulopathy, early postoperative bowel movement, the lowest intraoperative pH level, the temperature at the conclusion of the case, the location and duration of aortic cross clamping, the amount of fluid boluses administered after surgery, the amount of packed red blood cells administered during the case, and the average systolic blood pressure at admission and during surgery. Univariate analysis was performed with Fisher exact test, χ² test, and Student t test. Multivariate analyses also were performed with the variables that were found to be significant on the univariate analysis. Results: Thirteen of the 43 patients (30.2%) had colonic ischemia, and seven of the 13 underwent colonic resection (53.8%). The overall mortality rate was 51.2% (22/43)—five of the deaths were intraoperative and excluded from the study. In a comparison of the patients who had colonic ischemia with those who did not, statistically significant differences were found in the following variables: average systolic blood pressure at admission 90 mm Hg or less, hypotension of more than 30 minutes' duration, temperature less than 35°C, pH less than 7.3, fluid boluses administered after surgery 5 L or more, and packed red blood cells 6 units or more. Multivariate analysis indicated that the number of these variables present correlated significantly with the positive predicted probability of colonic ischemia occurring. No patient with two factors or fewer had an ischemic bowel, and the positive predictive probability of colonic ischemia for those patients with six factors was 80%. Conclusion: The results of this study show that: (1) colonic ischemia after rAAA may be predicted with the presence of two or more specific perioperative factors, (2) the lack of a guaiac-positive bowel movement may be misleading for the early diagnosis of colonic ischemia, and (3) more than 50% of the patients with colonic ischemia will require a colonic resection. We recommend that any patient with rAAA with more than two perioperative factors undergo sigmoidoscopy every 12 hours after surgery for 48 hours to rule out colonic ischemia without waiting for early or guaiac-positive bowel movement. (J Vasc Surg 1999;29:40-7.)     

腹主动脉瘤手术并发结肠缺血的临床分析

目的：探讨腹主动脉瘤（abdominal aortic aneurysm,AAA)手术并发结肠缺血的病因和防治措施。方法：对140例AAA手术并发经肠缺血的7例患者进行回顾性分析。结果：3例患者为AAA破裂急诊手术,7例患者均行AAA切除,人工血管置换术及肠系膜下动脉（inferior mesenteric artery,IMA)结扎术,有2例患者同时结扎双侧髂内动脉（internal iliac artery,IIA),2例患者同时结扎一侧IIA,3例患者行肠切除术,1例患者行IMA重,3例患者行保守疗法,术后3例患者因多器官功能衰竭死亡。结论：正确防治结肠缺血和坏死可有效降低AAA 手术病死率,有利于术后的康复。