Variation of infrarenal aortic diameter: A necropsy study

PURPOSE: To determine anatomicomorphological changes in the infrarenal portion of the abdominal aorta, we performed 645 dissections of the segment in corpses undergoing necropsy. METHODS: The aortas were removed from the corpses with a surgical technique; by means of a device that we designed, the external diameter of the artery was measured after luminal pressure was reestablished. This way, it was possible to avoid underestimation of the arterial diameter postmortem. The influence of age, sex, body size, arterial hypertension, chronic obstructive pulmonary disease, and coronary disease on the aortic diameter and the influence of different degrees of sclerosis on the infrarenal aorta wall were analyzed. Considering the diameters, aortas were regarded as "normal" when they did not present any ectasia, arteriomegaly, aneurysm, or hypoplasia. RESULTS: The sample involved 645 subjects whose ages ranged from 19 to 97 years (mean age, 55.8 years). Of the 645 subjects, 65.5% (423) were men, 34.5% (222) were women, 81% (523) were white, and 19% (122) were of another race. The diameters of arteries showing no anomalous dilatation (ectasis, arteriomegaly, or aneurysm) varied according to subject age, sex, body length, and the degree of atherosclerosis on the aorta wall (P <.01). Aortic diameters of those subjects with arterial hypertension, coronary disease, and chronic obstructive pulmonary disease were compared with the aortic diameters of control subjects, and significant differences were not shown (P >.05). Twenty-nine aneurysms were found (4.5% prevalence). Four were ruptured aneurysms, and all occurred in aortas with diameters larger than 5.0 cm. CONCLUSION: The infrarenal aortic diameter enlarges with aging, and this enlargement occurs earlier in men than in women. Those subjects who had a longer body length and advanced sclerosis on the aorta wall had larger aortic diameters. There was a high prevalence of infrarenal aneurysms (4.5%), with rupture found solely in aortas with diameters larger than 5.0 cm.     

Outcome of common iliac arteries after straight aortic tube-graft placement during elective repair of infrarenal abdominal aortic aneurysms

PURPOSE: To determine the relative rates of common iliac artery (CIA) expansion after elective straight aortic tube-graft replacement of infrarenal abdominal aortic aneurysms (AAA). METHODS: Five participating centers in this 2004 study entered patients they had managed by an aortoaortic tube graft for elective AAA repair. The procedures took place between January 1995 and December 2003. Postoperative computed tomography (CT) scans were obtained for all patients in 2004 to assess changes in CIA diameter. Measurements on preoperative and postoperative CT scans were all made at the same level using the same technique. RESULTS: Entered in the study were 147 patients (138 men, 9 women) with a mean age of 68 years. Mean follow-up from aortic surgery to verification of CIA diameter on the postoperative CT scan was 4.8 years. Mean preoperative CIA diameter was 13.6 mm vs 15.2 mm postoperatively. No patient developed occlusive iliac artery disease during follow-up. Three patients (2%) required repeat surgery during follow-up for a CIA aneurysm. The 147 patients were divided into three groups based on preoperative CIA diameter shown in CT scan: group A (n = 59, 40.1%), both CIA were of normal diameter; group B (n = 53, 36.1%), ectasia (diameter between 12 and 18 mm) of at least one CIA; group C (n = 35, 23.8%), an aneurysm (diameter >18 mm) of at least one CIA. CIA diameter increased by a mean of 1 mm (9.4%) over 5.5 years in group A vs 1.7 mm (12.1%) over 4.3 years in group B and 2.3 mm (12.7%) over 4.2 years in group C. The three patients who required repeat surgery for a CIA aneurysm during follow-up were all in group C. Four variables were associated with aneurysmal change in CIA: initial CIA diameter, celiac aorta diameter on the preoperative CT scan, a coexisting aneurysm site, and the follow-up duration. CONCLUSIONS: Tube-graft placement during AAA surgery is justified even for moderate CIA dilatation (<18 mm). CIA aneurysms with a preoperative diameter > or =25 mm enlarge more rapidly and warrant insertion of a bifurcated graft during the same surgical session as AAA repair. The evolutive potential of CIA between 18 mm and 25 mm in diameter justifies a bifurcated graft when the celiac aorta diameter is >25 mm or the patient's life expectancy is > or =8 years.     

大、小肾下型腹主动脉瘤的CT形态学特点

目的评价大、小肾下型腹主动脉瘤（AAA）的CT形态学特点。方法对45例肾下型AAA患者行64层螺旋CT血管成像（CTA）,并测定AAA形态学指标。以直径5cm为界,将患者分为大、小AAA两组,比较两组AAA的临床危险因素及形态学差异,分析瘤体大小与其他形态学特点的相关性。结果大AAA患者（n=25）收缩压小于小AAA（n=20）（P〈0．05）,吸烟比例大于小AAA（P〈0．05）。大AAA瘤体长度、近远端瘤颈直径、后壁血栓分布几率及瘤壁钙化积分大于小AAA（P〈0．05）。AAA瘤体长度与近端瘤颈角度（r=0．418,P〈0．01）及近端瘤颈直径呈正相关（r=0．411,P〈0．01）,与入口角度（r=-0．478,P〈0．01）及近端瘤颈长度呈负相关（r=-0．562,P％0．01）。结论肾下型AAA的瘤体大小与其他形态学特点具有一定的相关性。     

Computed tomography-detected abnormalities following conventional abdominal aortic aneurysm (AAA) repair

PURPOSE: To determine how time since the operation influences vascular abnormalities following conventional infrarenal abdominal aortic aneurysm (AAA) repair.METHODS: In 47 patients computed tomography was performed 1 to 12 years following the aneurysm repair. Aortic diameters at different levels were measured and other abnormalities recorded.RESULTS: Significant correlation was found between time since operation and diameter of the suprarenal aorta (R=0.51, P<0.001) but not with aortic neck diameter (R=-0.10, P=0.48) or diameter of the prosthetic graft (R=0.07, P=0.66). However, measured diameters of graft and aortic neck showed a significant positive correlation (R=0.40, P=0.005).CONCLUSIONS: Dilatation of the suprarenal aorta has a different pattern from aortic neck dilatation. The latter showed correlation with the diameter of the prosthetic graft. This may be of interest for future design of endovascular stent-grafts.     

Aminoterminal propeptide of type III procollagen and matrix metalloproteinases-2 and -9 failed to serve as serum markers for abdominal aortic aneurysm.

OBJECTIVES: Matrix-metalloproteinase (MMP)-2 and -9 and aminoterminal propeptide of type III collagen (NIIINP) have been reported to be elevated in patients with abdominal aortic aneurysm (AAA). The aim of our study was to test NIIINP, MMP-2 and -9 as potential serum markers for AAA in a large population group at risk for AAA. METHODS: Fifty-five to 70 year old men were screened for AAA by abdominal ultrasound. Simultaneously, blood samples were taken and the patients were interviewed for known risk factors for AAA. Patients with a dilatation of the infrarenal aorta of > or =25mm (Group 1, n=76) were compared to randomly assigned patients with normal aortic diameters (Group 2, n=83). A third group consisted of patients scheduled for operation of AAA (n=19). RESULTS: A total of 987 men were investigated with ultrasound. Seventy-six (7.7%) had an aortic dilatation > or =25mm. Aortic dilatation was correlated with age (P=0.0001). However, serum levels of NIIINP and MMP 2 were not different between the three groups of patients. For MMP-9 there was a weak inverse correlation with lower serum levels in patients with aortic dilatation (P=0.043). CONCLUSIONS: Both MMP-2 and -9 and NIIINP failed to show relevance as serum markers for aortic dilatation. Our results are, therefore, in contradiction to previous published results. AAAs cannot be diagnosed with a simple blood test.     

The value of screening in siblings of patients with abdominal aortic aneurysm.

OBJECTIVES: This study aimed to determine the incidence of abdominal aortic aneurysm (AAA) in a large group of siblings of Australian AAA patients to determine if screening in this group is justified. METHODS: 1254 siblings of 400 index AAA patients were identified and offered aortic ultrasound screening. An age and sex matched control group was recruited from patients having abdominal CT scans for non-vascular indications. AAA was defined by an infrarenal aortic diameter of > or =3 cm or a ratio of the infrarenal to suprarenal aortic diameter of > or =2.0. A ratio of 1.0-1.5 was considered normal, and a ratio of >1.5 to <2.0 was considered ectatic. Aortic enlargement was defined as ectasia or aneurysm. RESULTS: 276 (22%) siblings could be contacted and agreed to screening or had previously been diagnosed with AAA. All 118 controls had normal diameter aortas. 55/276 siblings had previously been diagnosed with AAA. The remaining 221 siblings underwent ultrasound screening. Overall, 30% (84/276) had enlarged aortas (5% ectasia, 25% aneurysmal); 43% of male siblings (64/150) and 16% of females siblings (20/126). The incidence was 45% in brothers of female index patients, 42% in brothers of male patients, 23% in sisters of female patients, and 14% in sisters of male index patients. CONCLUSIONS: The overall incidence of aortic enlargement of 30% found in this study warrants a targeted screening approach with ultrasound for all siblings of patients with AAA. A similar targeted approach for screening of the children of AAA patients would also seem advisable.     

Relationship of age,gender, race,and body size to infrarenal aortic diameter

Purpose: To assess the effects of age, gender, race, and body size on infrarenal aortic diameter (IAD) and to determine expected values for IAD on the basis of these factors.Methods: Veterans aged 50 to 79 years at 15 Department of Veterans Affairs medical centers were invited to undergo ultrasound measurement of IAD and complete a prescreening questionnaire. We report here on 69,905 subjects who had no previous history of abdominal aortic aneurysm (AAA) and no ultrasound evidence of AAA (defined as IAD ≥ 3.0 cm).Results: Although age, gender, black race, height, weight, body mass index, and body surface area were associated with IAD by multivariate linear regression (all p < 0.001), the effects were small. Female sex was associated with a 0.14 cm reduction in IAD and black race with a 0.01 cm increase in IAD. A 0.1 cm change in IAD was associated with large changes in the independent variables: 29 years in age, 19 cm or 40 cm in height, 35 kg in weight, 11 kg/m² in body mass index, and 0.35 m² in body surface area. Nearly all height-weight groups were within 0.1 cm of the gender means, and the unadjusted gender means differed by only 0.23 cm. The variation among medical centers had more influence on IAD than did the combination of age, gender, race, and body size.Conclusions: Age, gender, race, and body size have statistically significant but small effects on IAD. Use of these parameters to define AAA may not offer sufficient advantage over simpler definitions (such as an IAD ≥3.0 cm) to be warranted. (J Vasc Surg 1997;26:595-601.)     

基质金属蛋白酶及抑制因子与腹主动脉瘤临床病理特点的相关性研究

目的：研究基质金属酶（MMP）-2、MMP-9及抑制因子TIMP-1在腹主动脉瘤中的表达及与临床病理特征之间的关系。方法：应用免疫组化PV-9000通用型二步法对70例腹主动脉瘤和15例正常腹主动脉标本中的MMP-2、MMP-9及TIMP-1表达进行检测。结果：腹主动脉瘤组织中MMP-2和MMP-9蛋白表达阳性率明显高于正常腹主动脉组织,TIMP-1蛋白表达阳性率和正常腹主动脉没有统计学差异,（X^2=0.103,P=0.991）;MMP-2蛋白的表达与腹主动脉瘤的直径呈负相关（X^2=13.785,P=0.032）,MMP-9蛋白的表达与患者临床症状,腹主动脉瘤直径、破裂有相关性,（P〈0.05）,TIMP-1蛋白表达阳性率与临床病理特征无相关性（X^2=0.103,P=0.991）。结论：腹主动脉瘤组织中MMP高表达和TIMP的相对弱表达在腹主动脉瘤发生、发展过程中起重要作用,MMP-9可以预测腹主动脉瘤的自然病程从而作为腹主动脉瘤手术治疗的指征之一。     

Abdominal aortic aneurysms are associated with altered matrix proteins of the nonaneurysmal aortic segments

Purpose: Abdominal aortic aneurysms (AAA) are associated with diffuse arteriomegaly and peripheral aneurysms, suggesting a generalized process. Elastin and collagen are the key structural proteins of the aorta, and their relative content is markedly altered in tissue from AAA. Our purpose was to investigate elastin and collagen content in the proximal, nonaneurysmal segments of aortas with infrarenal AAA.Methods: After extraction of lipid, calcium, and soluble proteins, hydroxyproline (collagen) and desmosine-isodesmosine (elastin) contents were determined by high-performance liquid chromatography in the ascending and descending thoracic, supraceliac, and suprarenal aorta. By repeated measures of analysis of covariance, collagen was found to be increased throughout the aorta in AAA as compared with normal aorta or aorta with atherosclerotic occlusive disease. This difference remained significant when adjustments were made for group differences in age and degree of atherosclerosis. This increase in collagen content results in a dilutional decrease in elastin concentration. These data demonstrate that the same matrix protein alterations found in AAA tissue occur throughout the aorta, differing only in magnitude in the aneurysmal and nonaneurysmal segments. These data suggest that aneurysm formation may relate to alterations in the regulation of elastin and collagen. (J VASC SURG 1994;19:797-803.)     

Changes of the Infrarenal Aortic Segment After Conventional Abdominal Aortic Aneurysm Repair

OBJECTIVES: to delineate the natural history of the residual infrarenal aortic segment after conventional abdominal aortic aneurysm (AAA) repair. DESIGN: open prospective study. PATIENTS AND METHODS: between 1990 and 1997, 100 patients, who underwent conventional infrarenal AAA repair at our department, were followed annually by means of colour duplex ultrasonography. Data from 76 patients who had at least 3 scans were analysed. RESULTS: mean duration of follow-up was 4.7 years (range: 3-8 years). The residual infrarenal aorta dilated a mean of 0.57 mm annually. No patient required reoperation. There was no significant correlation between dilatation and any of the recorded risk factors except for the initial neck diameter (p=0.03). CONCLUSIONS: conventional AAA surgery is durable so that surveillance, during the first 5 postoperative years, is not justified in terms of cost-effectiveness. The impact of such a dilatation on endovascular AAA repair requires further investigation.     

血管平滑肌细胞凋亡在腹主动脉瘤发病中的作用

目的：探讨腹主动脉瘤（AAA）中膜血管平滑肌细胞（VSMC）密度降低的机制。方法：选取人体肾下AAA及正常腹主动脉组织（NA）标本,采用免疫组化及原位末端DNA标记技术,测定中膜VSMC,凋亡细胞及其相关蛋白,计算机图像分析并计算VSMC密度及凋亡指数。结果：与NA相比,AAA中膜VSMC密度降低,VSMC凋亡指数及其相关蛋白P53,P21明显增加,而bcl-2无显变化。结论：VSMC凋亡在细胞水平参与腹主动脉结构损伤与重构,促进AAA形成。     

Experience with endovascular grafts in the treatment of infrarenal aortic aneurysms associated with proximal aortic dissection

BACKGROUND: Chronic abdominal and thoracic aortic dissections often present with concomitant infrarenal aortic dilatation. We conducted a retrospective review of 6 patients treated with endovascular stent grafts for coexisting aortic dissection and infrarenal aneurysm. METHODS: Six patients with suprarenal aortic dissections and infrarenal aortic aneurysms (AAA) had their AAAs treated with endovascular grafts. Grafts were constructed of balloon expandable Palmaz stents and expanded polytetrafluoroethylene graft. The device was inserted transfemorally and deployed under fluoroscopy. RESULTS: Successfully primary AAA exclusion was achieved in 5 patients. One patient required a supplemental stent placed above the endograft and into the true lumen to seal the endoleak. No aneurysm has enlarged, and all remain thrombosed for 9 to 24 months (mean 20). One type III dissection enlarged 2 weeks after endograft insertion. One patient had uncomplicated cephalad fenestration of a dissection by the endograft. CONCLUSIONS: Endovascular grafts may be used to treat coexisting AAA and aortic dissection. Attention to the site or sites of reentry of a dissection is essential to insure full aortic aneurysm exclusion. The fate of a chronic aortic dissection cephalad to an endovascularly treated AAA is unclear and will require longer follow-up.     

Pararenal aortic aneurysms: definition, classification, directions for surgery

The formidable impact derived by the endovascular correction (Evar) of abdominal aorta aneurysms (AAA), has risen its classification aspects. The topographical criteria has assumed importance in decisional diagnostic-therapeutic strategy especially in cases of so called pararenal aneurysms (PRAA). DEFINITION: PRAA defines aneurysm being involved underenal juxtarenal aorta (JRA), or more rarely, suprarenal aorta with normal aortic diameter at level of celiac (JRA), or more rarely, suprarenal aorta with normal aortic diameter at level of celiac trunk. CLASSIFICATION: The morphologic-topographic aspect is considered in function of selection or eligibility of patients to Evar or standard open surgery, in the need of a suprarenal clamping for the tailoring of proximal anastomosis or anchorage of endoprotesis. Various specific classifications for these aneurysms have been proposed (Schumacher, 1997; Wolf, 2000; Ayari, 2001) that considers: 1. Aneurysm collar: short/long/tortuous, 2. Relations with renal arteries, 3. Relations with the left renal vein. DIRECTIONS FOR SURGICAL TREATMENT: The choice between the technical solution to prefer either open or endovascular surgery will have to consider a series of additional variables to the standard direction common to every AAA based on dimensions and morphology. Priority will have to be given to evaluating, using shared morphologic-topographical classification criteria, real incidence of PRAA-JRA (3%-20% in literature review); greater post opening mortality (1.3%-15.3%); dimensions (AAA with diameter > or = 5.5 cm in operating risk assessment of single patient, in clinical evolution and increase in the time of the lesion); in common occurrence in AAA of steno-obstructive lesions of renal arteries and involvement of same ones in the aneurysm collar in need of reconstruction and suprarenal aortic clamping.     

Natural history of the residual infrarenal aorta after infrarenal abdominal aortic aneurysm repair

Purpose: We determined the natural history of the residual native infrarenal aortic segment after conventional abdominal aortic aneurysm (AAA) repair. Methods: For the retrospective arteriographic case series, 800 hundred translumbar aortograms (TLAs) were obtained for 272 patients, before and after conventional AAA repair. The main outcome measures were changes in the aortographic diameter and the length of the infrarenal aortic segment, corrected and uncorrected for magnification by normalization to the first lumbar vertebral body height. Results: The mean follow-up time from the preoperative TLA to the most recent postoperative TLA was 42 months (range, 1 to 257 months). Vertebral body height did not change p = 0.35). The length of the native infrarenal aorta cephalad to the proximal anastomosis increased a mean of 3 mm, from 23 to 26 mm p = 0.001). However, in 115 patients (43%), this aortic segment elongated more than 5 mm, and in 63 patients (24%), it elongated more than 10 mm. The native residual infrarenal aorta above the proximal anastomosis dilated a mean of 1 mm, from 23 to 24 mm p = 0.001), but in 21 patients (8%), it dilated more than 5 mm. There was a weak positive correlation between the increase in residual native aortic diameter and duration of follow-up. There was a negative correlation between this increase and the initial size. The diameters of the proximal anastomosis and proximal graft did not change. Marked variability in the changes in aortic dimensions was observed. Conclusions: A mean period of 42 months after conventional AAA repair, the native infrarenal aortic segment elongates and dilates. Although such enlargement is statistically significant, the average increase appears to be small. However, residual aortic cuff diameter increased more than 5 mm and neck length more than 10 mm in a significant number of patients, with potentially serious implications for endovascular treatment of AAA. (J Vasc Surg 1998;27:805-12.)     

Cigarette smoking increases aortic dilatation without affecting matrix metalloproteinase-9 and -12 expression in a modified mouse model of aneurysm formation

OBJECTIVE: The development of abdominal aortic aneurysms (AAA) is presumed to result from multiple genetic and environmental factors, with exposure to tobacco smoke the single largest known factor predisposing to aneurysm growth. We have attempted to adapt the elastase-perfused animal model to determine whether tobacco exposure can lower the threshold of aortic injury necessary for AAA development. METHODS: Adult C57BL/6 mice underwent transient perfusion of the infrarenal aorta with an active solution of elastase: high-dose (HDE, 0.19 U/mL, n=9), standard-dose (SDE, 0.16 U/mL, n=21) or low-dose (LDE, 0.07 U/mL, n=24). Control animals (n=24) were treated with heat inactivated elastase (HIE). Twenty LDE perfused mice were exposed to cigarette smoke (LDE-S) beginning 2 weeks before perfusion and continuing until aortic harvest. Aortic diameter (AD) was measured preperfusion, postperfusion, and at harvest on day 14. AAA was defined as %DeltaAD>or=100% between preperfusion and harvest. Aortas from each group (except HDE) were analyzed for matrix metalloproteinase-9 (MMP-9) and MMP-12 expression by real-time polymerase chain reaction normalized to glyceraldehyde-3-phosphate dehydrogenase. RESULTS: All SDE mice developed large AAA by %DeltaAD (189.3%+/-16.9%, mean+/-standard error of the mean), but control mice had only a small dilatation (69.7%+/-3.7%, P<.01). Higher doses of elastase did not produce larger aneurysms in HDE mice. In contrast, only 63% of LDE mice showed aneurysmal dilatation, and these were significantly smaller (104.3%+/-4.2%, P<.01). When exposed to cigarette smoke, LDE animals developed significantly larger aneurysms (%DeltaAD, 134.5%+/-7.9%, P=.0021). There was no difference in normalized aortic MMP-9 and MMP-12 expression between elastase doses or between smoke-exposed and unexposed animals. Histologic analysis revealed that smoking increased the extent of aortic elastin degradation when compared with LDE-S animals. CONCLUSION: Aneurysm development in the elastase model is dependent on the quantity of active elastase infused. Exposure of animals to tobacco smoke after a relatively minor aortic elastase injury produces increases in elastin degradation and aneurysm size without affecting MMP-9 or MMP-12 expression. To our knowledge, this is the first demonstration in an animal model that smoking can act as a synergistic factor in AAA development. Further understanding of the relationship between smoking and AAA in this model may help unveil the pathophysiologic pathways involved between cigarette smoke and AAAs.     

大鼠腹主动脉瘤残余应力分析

目的 用测量张开角的方法研究大鼠腹主动脉瘤模型的应力分布，研究腹主动脉瘤壁的顺应性和临床预测腹主动脉瘤的破裂风险。方法 用猪弹力蛋白酶灌注Wistar大鼠腹主动脉建立梭形肾下腹主动脉瘤模型，测量并对比腹主动脉瘤动脉环和正常腹主动脉环的蠕变速度，残余应力，对比腹主动脉瘤不同部位的残余应力，动脉环内径和瘤壁厚度。结果 梭形腹主动脉瘤模型建立的成功率90%，腹主动脉瘤动脉环蠕变速度较正常腹主动脉快，腹主动脉瘤入口和出口的残余应力值最大，内径和瘤壁厚度最小，结论 残余应力可以量化腹主动脉瘤瘤壁的顺应性，用测量残余应力的方法发现腹主动脉瘤的顺应性较正常主动脉小，腹主动脉瘤入口和出口附近应力最大，但保护作用最小，是可能破裂的部位。     

True juxta-anastomotic aneurysms in the residual infra-renal abdominal aorta.

INTRODUCTION: abdominal aortic dilatation can occur above the graft following repair of infra-renal abdominal aortic aneurysm (AAA). This study aimed to determine the incidence and possible aetiological associations of recurrent juxta-anastomotic aneurysms following open repair of AAA. METHODS: the diameter of the infra-renal aorta above the graft of 135 patients who had previously undergone open AAA repair was determined using ultrasound. In those where the diameter was greater than 40 mm a CT scan was undertaken. Co-morbid and operative details were determined from the patients and their clinical notes. RESULTS: seven patients had true juxta-anastomotic aneurysms (>40 mm) in the residual infra-renal abdominal aorta, the occurrence of which was associated with tobacco smoking and hypertension. There was no association with other co-morbid factors, surgical operative details or the development of iliac aneurysms (which occurred in 3% of patients). CONCLUSIONS: true juxta-anastomotic aneurysms develop in the residual infra-renal neck of patients following open repair of abdominal aortic aneurysm. Tobacco smoking and hypertension are significant factors associated with the development of these aneurysms. This group of patients may warrant surveillance to prevent aneurysm rupture.     

Results of supraceliac aortic clamping in the difficult elective resection of infrarenal abdominal aortic aneurysm

We have used clamping of the aorta above the celiac axis (SC) in 30 of 431 elective resections of infrainguinal abdominal aortic aneurysms (AAA) during the past five years as an alternative to a difficult aortic cuff dissection. The results of SC clamping in these 30 patients are compared with the results of 379 routine aneurysm resections with infrarenal (IR) clamping and 22 additional aneurysm resections where the clamp was placed immediately above the renal arteries. These difficult cuff dissections occurred in 12 patients with inflammatory AAA, in 11 patients with juxtarenal AAA, and in seven patients with recurrent or noninfected false AAA of the proximal cuff. Patients with ruptured or suprarenal aneurysms and those undergoing combined operation for a visceral ischemic syndrome and an aneurysm were excluded from this study. Patients with SC clamping had similar operative mortality rates, comparable renal function, and frequency of cardiac events as patients with IR clamping. Blood loss was slightly higher in the SC group (p = 0.07) and serum aspartate amino transferase (AST) levels were three times higher than in the IR group; however, this was of no clinical significance. In contrast, those 22 patients whose aortas were clamped immediately above the renal arteries (AR) had higher perioperative mortality rates (2% IR, 3% SC vs 32% AR) and a higher incidence of kidney failure requiring dialysis (1% IR, 3% SC vs 23% AR). The mean values of serum creatinine and blood urea nitrogen were also significantly higher in the AR group when compared with both the IR and the SC groups (IR: 25 and 1.5 mg/dl, respectively; SC: 27 and 1.8 mg/dl; AR: 41 and 3.5 mg/dl). The single most important risk factor accounting for the differences between clamping above the celiac artery and clamping above the renal arteries was the presence of atherosclerotic debris in the nonaneurysmal, juxtarenal aortic segment. Clamping the aorta with juxtarenal atherosclerosis caused either atheroembolization to kidneys, legs, and intestine or injury to the aorta, renal arteries, or both; it was the cause of morbidity in all five cases of kidney failure requiring dialysis and accounted for all seven of the deaths in the AR group. SC clamping does not add risk to the patient undergoing resection of an infrarenal AAA and is the preferred method of achieving proximal control of the infrarenal aorta when a a hazardous cuff dissection is likely.(ABSTRACT TRUNCATED AT 400 WORDS)     

The fate of the infrarenal aortic neck after open aneurysm surgery

Purpose: The long-term success of the endovascular repair of abdominal aortic aneurysms is dependent on the secure fixation of the stent graft at the proximal and distal attachment sites. A progressive dilatation of the infrarenal neck may jeopardize this success. The data regarding this issue are scarce. However, the long-term fate of the infrarenal neck can be studied in patients who have undergone open aneurysm surgery. This was the purpose of the present investigation. Methods: Between January 1989 and December 1993, 64 patients underwent open repair of infrarenal abdominal aortic aneurysms. Of the 36 patients who were eligible for the study, 19 had preoperative computed tomography scans that were available. The 19 patients also underwent a new computed tomography scanning at a mean of 71 ± 12 months after surgery. Results: The mean preoperative aortic diameter was 25.4 ± 3.7 mm at the infrarenal neck, 24.8 ± 3.4 mm at the level of the renal arteries, and 26.7 ± 3.0 mm at the level of the superior mesenteric artery (SMA). The mean aortic diameter increased at all of the 3 levels: +2.8 ± 3.1 mm (P = .0014) at the infrarenal neck, +2.8 ± 3.0 mm (P = .0013) at the level of the renal arteries, and +1.3 ± 3.0 mm (P = .080) at the level of the SMA. The annual growth rate was 0.48 mm/y (P = .0023) at the infrarenal neck, 0.46 mm/y (P = .0010) at the level of the renal arteries, and 0.21 mm/y (P = .5811) at the level of the SMA. No correlation was found between the preoperative infrarenal neck diameter (r = .295, P = .2194), the preoperative aortic diameter at the level of the renal arteries (r = .302, P = .2088), and the preoperative aortic diameter at the level of the SMA (r = .314, P = .2043) and the corresponding growth rates. The patients were stratified into 2 groups—one with a small annual growth rate at the infrarenal neck (n = 11; ≤0.3 mm/y) and one with a larger annual growth rate (n = 8; >0.3 mm/y)—and no differences in the preoperative infrarenal neck diameter or the clinical characteristics were found between the groups. Conclusion: This investigation shows an aortic dilatation of the infrarenal neck and of the aorta at the level of the renal arteries of approximately 0.5 mm annually after open aneurysm surgery. This dilatation raises concern regarding the long-term success after endovascular repair. The data also indicate that 2 populations might exist with regard to the annual growth rate of the infrarenal neck—one with low growth rate and one with higher growth rate. This might be of interest for the future selection of patients for endovascular repair. (J Vasc Surg 1998;28:889-94.)