Infrarenal Aortic Aneurysm Research Articles

Endovascular repair of aortic aneurysms: Critical events and adjunctive procedures

Objective: We sought to define the learning curve relative to the incidence and range of intraoperative problems and to establish guidelines for troubleshooting during the endovascular repair of infrarenal aortic aneurysms. Methods: We prospectively evaluated our first 75 consecutive cases over a 12-month period and focused on perioperative critical events and adjunctive procedures as categorical outcome measures collected during the operation. Patients were separated into three groups on the basis of the date of their operation, such that group 1 consisted of our first 25 cases, group 2 our next 25 cases, and group 3 our last 25 cases. Results: At least one critical event and adjunctive procedure marked 67 (89%) of 75 cases. In 51%, there were at least two critical events and adjunctive procedures. There were no immediate open conversions or intraoperative deaths. Access problems occurred in 28% of the 75 cases and were addressed by use of brachial-femoral artery access (30%), iliac artery/aortic bifurcation balloon angioplasty (8%), and iliofemoral conduits (4%). Graft foreshortening was the most common deployment event (44%), necessitating distal covered extensions. Iliac graft limb twists and kinks occurred in 12% of cases and were managed with balloon angioplasty and uncovered stents. General incidents included balloon ruptures (10%), arterial dissections (6%), iliac artery rupture (2.6%), and lower extremity ischemia (4%). The two cases of iliac artery rupture were managed with distal covered extensions, and there were no cases of atheroemboli. Intraoperative endoleaks were encountered in 44% of the cases and included proximal attachment sites (15%), distal attachment sites (9%), type 2 sources, and “blushes.” Management of intraoperative endoleaks included proximal/distal covered extensions and re-ballooning. Our 30-day endoleak rate was 20%. The incidence of critical events did not decrease in the latter one third compared with the first two thirds of cases. Conclusions: Critical events occur frequently during endovascular repair of aortic aneurysms. The intraoperative problems range from the common endoleaks, access and deployment issues, and balloon ruptures, to rare but life-threatening complications such as iliac artery rupture. A toolbox of accessories that includes wires, catheters, large balloons, covered proximal and distal extensions, and uncovered stents is essential given the frequency of adjunctive procedures. Successful aortic endografting requires more than mere familiarity with basic endovascular techniques. (J Vasc Surg 2001;33:1226-32.)

Carbon dioxide angiography for endovascular grafting in high-risk patients with infrarenal abdominal aortic aneurysms

Allergic reactions to contrast media, preexisting renal dysfunction, and hyperthyroidism are relative contraindications for angiography with conventional contrast medium. Carbon dioxide (CO2) angiography is an alternative method in high-risk patients because CO2 is nontoxic, without allergic potential, and not iodic. CO2-related complications are extremely rare. Because renal insufficiency often occurs in vascular patients, this method will become increasingly important for endovascular surgery. We report on three consecutive patients with asymptomatic infrarenal aortic aneurysm and concomitant renal dysfunction or allergic reactions to standard contrast media. Aortic stent grafts were deployed under CO2 angiographic control without complications or worsening of renal function. (J Vasc Surg 2001;33:646-9.)

Renal Artery Endarterectomy for Treatment of Renovascular Hypertension Combined with Infrarenal Aortic Reconstruction: Analysis of Surgical Results

From June 1995 to February 2000, 16 patients with renovascular hypertension had bilateral transaortic renal artery endarterectomy (RA TEA) combined with either infrarenal aortic aneurysm repair (8 patients) or infrarenal aortodistal bypass for occlusive disease (8 patients). Aortic clamp level for RA TEA was supraceliac in eight patients and suprarenal in eight patients with a mean clamp time of 19 min (range 14 to 25 min). Perioperative complications occurred in four patients. These included respiratory insufficiency with prolonged intubation (1 patient), prolonged intubation with transient renal failure requiring temporary dialysis (1 patient), acute thrombosis of right limb of aortofemoral bypass graft (1 patient) and major left hemispheric cerebrovascular accident (1 patient). Results from this contemporary patient series demonstrate acceptable perioperative morbidity and mortality when RA TEA for treatment of renovascular hypertension is combined with infrarenal aortic reconstruction. In this setting, either supraceliac or suprarenal aortic clamping for short time periods appears to be well tolerated. Clinical outcome is enhanced by salvage of renal function, decrease in medication requirement, and improvement in blood pressure control.

Results of an aortic endograft trial: Impact of device failure beyond 12 months

Purpose: Analysis endpoints of patient survival and aortic rupture at a reporting interval of 12 months are regularly used to compare endograft aortic aneurysm (EAG) repair to conventional open surgical (COS) repair. This study reports a multicenter EAG repair versus COS repair parallel cohort trial at 12 months and additional observations of specific device failure types and their impact on an aortic endograft design beyond that follow-up period. Methods: From August 1997 to September 1998, 240 patients who were treated with bifurcation EAG repairs and 28 patients who were treated with straight EAG repairs were compared with 98 patients who were treated with COS repair for elective infrarenal aortic aneurysm repair. Allocation to treatment was based on aneurysm anatomy. All cohorts underwent infrarenal procedures. Data from concurrent, nonrandomized patient accrual from 17 United States institutions were prospectively gathered and independently adjudicated for safety and efficacy. An independent core laboratory evaluated all imaging data. Results: There were 308 men and 58 women (mean age, 72 years; range, 42-94 years) treated for infrarenal aortic aneurysm (mean diameter, 55 mm; range, 40-115 mm). Mean preoperative aneurysm diameters were clinically similar (EAG repair, 54 mm vs COS repair, 57 mm). The two cohorts were not significantly different in terms of gender (P = .30) or age (P = .32). EAG repair technical success (aneurysm exclusion, graft patency, patient survival) at 30 days was 89.2%. Five patients required immediate conversion to COS repair, four caused by access complications and one caused by operator-induced EAG repair malposition. The 30-day mortality rate was 1.5% for EAG repair and 3.1% for COS repair (P = .59). The 12-month survival rate was 94.3% for EAG repair and 95.9% for COS repair. The intermediate-term cumulative survival rate at 24 months was 84.9% for EAG repair and 80.3% for COS repair (P = .48). EAG repair device failure occurred from fabric erosion in six patients, with two deaths from ruptured aneurysm at 18 and 28 months after endografting and four device failures resolved by secondary procedures. Five endograft limb dislocations were all resolved by secondary endovascular procedures. Major or minor endograft migration required secondary procedures in five patients, including conversion in two patients. Conclusion: The clinical outcome at 12 months demonstrated effective aneurysm treatment and comparable safety between EAG repair and COS repair by conventional endpoints. Ongoing follow-up beyond 12 months revealed device-related adverse events that required endograft design changes. Diligent surveillance of outcomes beyond 12 months is necessary to adequately evaluate EAG repair devices. (J Vasc Surg 2001;33:S55-63.)

Gender-related differences in infrarenal aortic aneurysm morphologic features: Issues relevant to Ancure and Talent endografts

Purpose: The purpose of this study was to determine whether gender-related anatomic variables may reduce applicability of aortic endografting in women. Methods: Data on all patients evaluated at our institution for endovascular repair of their abdominal aortic aneurysm were collected prospectively. Ancure (Endovascular Technologies (EVT)/Guidant Corporation, Menlo Park, Calif) and Talent (World Medical/Medtronic Corporation, Sunrise, Fla) endografts were used. Preoperative imaging included contrast-enhanced computed tomography and arteriography or magnetic resonance angiography. Results: One hundred forty-one patients were evaluated (April 1998–December 1999), 19 women (13.5%) and 122 men (86.5%). Unsuitable anatomy resulted in rejection of 63.2% of the women versus only 33.6% of the men (P = .026). Maximum aneurysm diameter in women and men were similar (women, 56.94 ± 8.23 mm; men, 59.29 ± 13.22 mm; P = .5). The incidence of iliac artery tortuosity was similar across gender (women, 36.8%; men, 54.9%; P = .2). The narrowest diameter of the larger external iliac artery in women was significantly smaller (7.29 ± 2.37 mm) than in men (8.62 ± 2.07 mm; P = .02). The proximal neck length was significantly shorter in women (10.79 ± 12.5 mm) than in men (20.47 ± 19.5 mm; P = .02). The proximal neck width was significantly wider in women (30.5 ± 2.4 mm) than in men (27.5 ± 2.5 mm; P = .013). Proximal neck angulation (>60 degrees) was seen in a significantly higher proportion of women (21%) than men (3.3%; P = .012). Of the patients accepted for endografting, a significantly higher proportion of women required an iliofemoral conduit for access (women, 28.6%; men, 1.2%; P = .016). Conclusion: Gender-related differences in infrarenal aortic aneurysm morphologic features may preclude widespread applicability of aortic endografting in women, as seen by our experience with the Ancure and Talent devices. In addition to a significantly reduced iliac artery size, women are more likely to have a shorter, more dilated, more angulated proximal aortic neck. (J Vasc Surg 2001;33:S77-84.)

Endograft treatment of anastomotic aneurysms following conventional open surgery for infrarenal aortic aneurysms.

to evaluate the use of endograft therapy for treating anastomotic aneurysm following open surgical repair of infrarenal aneurysms of the abdominal aorta. four male patients (age 47-75 years) at high surgical risk (ASA IV n=3, ASA III n=1) developed secondary aneurysms at the site of the central (four aneurysms) and additional peripheral (two aneurysms) anastomosis of their tube or bifurcation prosthesis an average of 13 years (range 1-23 years) after conventional open surgical correction of infrarenal aneurysm of the abdominal aorta. In two patients, there was covered rupture of the aneurysm sac. The aneurysm diameter was 4.8 cm, 8.0 cm, 7.4 cm, 7.0 cm, respectively (mean 6.8 cm). Follow-up included helical CT imaging at 1 week, 3 months and 6 months postoperatively. anastomotic aneurysm was successfully treated in all four cases. No evidence of endoleak was observed during the follow-up period. Two patients died 14 and 18 days after surgery due to myocardial infarction and cerebrovascular accident. The endovascular repair of the two patients who died was intact. although no long-term results are available, the use of a graft-in-graft method to repair anastomotic aneurysms following conventional implantation of tube or bifurcation prostheses appears to be effective, particularly in patients at high surgical risk.

Explantation of aortic stent-grafts

Endoluminal stent graft placement for the treatment of infrarenal aortic aneurysms (AAA) has gained widespread acceptance because it is associated with lower perinterventional morbidity than conventional transabdominal surgery. In this study the long-term morbidity of the procedure was evaluated. Between 9/94 and 12/98, 150 patients (age = 69.6 +/- 8.5 y; m = 142, f = 8) with AAA were treated by placing an intravascular nitinol stent graft (Stentor, n = 55; Vanguard-System, n = 95; 8 tubular grafts, 142 bifurcated grafts). Initial placement of the stent graft was successful in 144 patients. In 12 % of stent graft placements we encountered one of the following complications (n, days after stent placement): migration or dislocation of the prosthesis (4, 914 +/- 220 d), rupture of the aorta (2, 452 d/802 d), recurrent thrombosis of the stent graft (3, 478 +/- 359 d), endoleak (3, 955 +/- 472 d), infection of the prosthesis (5, 798 +/- 495 d). There was no correlation between the complications and the type of stent used. All of these patients were treated by surgical replacement of the prosthesis with a dacron graft. 1. The results suggest that most complications are due to a continuation of the disease process leading to loosening of the prosthesis. 2. Explantation of the prosthesis and surgical repair is feasible but bears additional risks. 3. Since the onset of reperfusion of the excluded aneurysm can not be predicted, all patients with infrarenal aortic stent grafts require frequent computer tomographic follow up. 4. Lastly, the results call for further improvements in the design of the stent graft.

Unusual hypotension in the ITU

Dear Sir A 71-year-old man presented to the emergency department with a history of sudden onset of abdominal pain and feeling extremely unwell. He was taken ill suddenly while waiting for a bus. The vascular surgeons made a diagnosis of a leaking aortic aneurysm (but which was contained), and he was rushed to the operating theatre. The patient was stable cardiovascularly in the emergency room, and was actually hypertensive, with systolic blood pressure above 170 mmHg. He was found to be even more hypertensive in the anaesthesia room, with a systolic blood pressure of 200 mmHg. A 5-cm infrarenal aortic aneurysm was found at laparotomy, but it was not ruptured. There seemed to be no other pathology in the abdomen to explain his condition. This aneurysm was repaired uneventfully and the anaesthesia management was unremarkable, with stable cardiovascular and respiratory parameters. On closer examination of his medical notes, it was apparent the patient had moderate chronic obstructive airways disease, along with mild-to-moderate aortic and mitral valve regurgitation and some inferior wall hypokinesia that had been identified in a previous echocardiogram. It was thus felt prudent to transfer him to the intensive care unit for overnight monitoring and further stabilization. It was decided to keep him sedated, with his trachea intubated and lungs ventilated until the morning. After approximately half an hour of his arrival to the intensive care unit, his blood pressure began to decrease. This responded initially to fluid administration, but subsequently decreased, with a lowering of the central venous pressure. Examination of his abdomen and drains did not indicate any leak from his recently repaired aneurysm. While a diagnosis of primary myocardial failure was being considered (given his previous history), it was discovered that a 10-mg glyceryl trinitrate patch had been applied to the lateral chest wall. This was promptly removed, and it was then revealed that the patch had been applied in the anaesthesia room as an adjunct to lower his high blood pressure. This information had not been passed on to the intensive care personnel on transfer of the patient by the theatre team. The adrenaline infusion, which was being prepared, was no longer required and the patient remained stable thereafter. This illustrates not only the importance of communication when patients are transferred from one area to another, but also the importance of re-examining them completely, even when all seems to be in perfect order at first glance.

Morphology and diameter of infrarenal aortic aneurysms: a prospective autopsy study

Purpose: To determine the diameter and morphology of infrarenal aortic aneurysms in 78 fresh autopsy specimens. Methods: To avoid underestimation of the arterial diameter postmortem and to re-establish aneurysm morphology, a device was designed and introduced into the vessel, inflated to 80 mm Hg, and the largest external diameter was measured. Results: The ages of the individuals ranged from 40 to 97 yr (mean 70). Thirty-eight aneurysms were ruptured with diameters ranging from 5.3 to 17.0 cm (mean 7.97), and 40 aneurysms were nonruptured with variations in diameters from 2.8 to 6.1 cm, mean 4.02 cm ( P<0.01). Fusiform aneurysms were more frequent, and when they ruptured their diameters were smaller than the diameters of the spherical aneurysms ( P<0.05). Aneurysms ruptured more frequently in the posterior wall (67%) and in the inferior portion (61%). A mural thrombus was found at the site of rupture in 80% of the specimens. Conclusion: In our samples, rupture was found solely in those aneurysms with a diameter over 5.0 cm, ruptures occurred earlier in fusiform aneurysms, mural thrombus was not a protective factor, and finally, aneurysms ruptured mainly in the posterior and inferior portions.

3D vascular imaging with power mode in planning and controlling percutaneously implanted abdominal aortic stent grafts

Evaluation of the reliability of vascular ultrasound with power mode and 3D-power mode for preinterventional planning before endovascular treatment of abdominal aortic aneurysms and postoperative follow-up after endografting. A new real-time 3D technique with power mode flow imaging was used in a prospective study of 75 patients with infrarenal aortic aneurysms, in 25 cases before and in 50 cases after stentgraft implantation. The results of vascular ultrasound with color-coded duplex sonography (CCDS), power mode and 3D power mode were compared with CTA and DSA in all cases. Only the length and diameter of the aneurysm could be reliably measured by sonography. Additional 3D reconstructions could show flow parameters in the aneurysm more clearly, but imaging of the proximal and distal anchoring zone was only achieved insufficiently. After stentgraft implantation, possible complications like thrombus formation in the graft (4/50) and endoleaks (15/50) were clearly seen by power sonography. 9 anchoring leaks and 6 side-branch endoleaks were found. 3D power mode made localizing and imaging of aneurysm reperfusion easier. Detection of the origin of side-branch endoleaks was achieved only by DSA. Stent frame fractures (4/50) were difficult to see by ultrasound. Vascular ultrasound with power mode and 3D power mode makes the imaging of complications after endoaortic stentgraft implantation like endoluminal thrombus formation or endoleaks and the documentation of aneurysm reperfusion easier compared to CCDS. 3D reconstructions show the dimensions of the aneurysm but are not able to substitute CTA and DSA with measuring catheter for preinterventional planning.

Incidence and risk factors of late rupture, conversion, and death after endovascular repair of infrarenal aortic aneurysms: The EUROSTAR experience

Objective: The EUROSTAR (European Collaborators on Stent/graft techniques for aortic aneurysm repair) Registry was established in 1996 to collect data on the outcome of treatment of patients with infrarenal aortic aneurysms with endovascular repair. To date, 88 European centers of vascular surgery have contributed. The purpose of the study was to evaluate the results of this treatment in the medium term (up to 4 years) according to the analysis of “hard” or primary end points of rupture, late conversion, and death. Patients and Methods: Patients with aortic aneurysms suitable for endovascular aneurysm repair were notified to the EUROSTAR Data Registry Centre before treatment to eliminate bias due to selective reporting. The following information was collected on all patients: (1) demographic details and the anatomic characteristics of their aneurysms, (2) details of the endovascular device used, (3) complications encountered during the procedure and the immediate outcome, (4) results of contrast enhanced computed tomographic imaging at 3, 6, 12, and 18 months after operation and at yearly intervals thereafter, and (5) all adverse events. Life table analysis was performed to determine the cumulative rates of (1) death from all causes, (2) rupture, and (3) late conversion to open repair. Risk factors for rupture and late conversion were identified through regression analysis. Results: By March 2000, 2464 patients had been registered, and their mean duration of follow-up was 12.19 months (SD, 12.3 months). There were 14 patients with confirmed rupture of their aneurysms. The cumulative rate (risk) of rupture was approximately 1% per year. Emergency surgery was undertaken in 12 (86%) patients, of whom five (41.6%) survived. Two patients who were not treated surgically also died, which resulted in an overall death rate of 64.5% (9/14) of the patients. Significant risk factors for rupture were proximal type I endoleak (P =.001), midgraft (type III) endoleak (P =.001), graft migration (P =.001), and postoperative kinking of the endograft (P =.001). Forty-one patients underwent late conversion to open repair with a perioperative mortality rate of 24.4% (10/41). The cumulative rate (risk) of late conversion was approximately 2.1% per year. Risk factors (indications) for late conversion were proximal type I endoleak (P =.001), midgraft (type III) endoleak (P =.001), type II endoleak (P =.003), graft migration (P =.001), graft kinking (P =.001), and distal type I endoleak (P =.001). Conclusions: Endovascular repair of infrarenal aortic aneurysms with the first- and second-generation devices that predominated in this study was associated with a risk of late failure, according to an analysis of observed hard end points of 3% per year. Action taken to address the risk factors identified by the study may improve results in the future. (J Vasc Surg 2000;32:739-49.)

Changes in the region and the proximal aneurysm neck after endovascular repair of infrarenal aortic aneurysms

To analyze short and mid-term changes of the proximal aneurysm neck and to evaluate renal function after endovascular repair of infrarenal abdominal aortic aneurysms. 24 of 29 patients, who were treated endoluminally with the bifurcated Vanguard Stent graft between 1997 and 1999 underwent spiral CT follow-up after 1, 3, 6 and every 12 months. Mean follow-up period was 10.5 months (3-32 months). Follow-up included spiral CT scanning. The aortic diameter as well as cross-sectional area were measured. Stent graft position and renal perfusion were checked by spiral CT. Serum creatinine levels were determined preoperatively and during follow-up. Supra- and infrarenal aortic sizes remained stable. No correlation to the distance between the stent-graft and the renal arteries was observed. Caudal migration of the stent-graft with an average of 6.5 (3-15) mm occurred in 13 patients. Cranial migration was observed in 3 patients. Uncovered stent wires partially overlapped at least one renal artery in 18 patients. No renal infarction occurred. No significant increase of the serum creatinine level was found. The risk of proximal endoleakage due to post-interventional dilatation of the aorta abdominalis seems to be low. Insufficient stent graft fixation requires a wide distance between the proximal end of the stent graft and the aneurysm. In the mid-term uncovered stent wires overlapping the renal arteries had no relevant influence on renal function.

Relationship between preoperative patency of the inferior mesenteric artery and subsequent occurrence of type II endoleak in patients undergoing endovascular repair of abdominal aortic aneurysms

Objectives: The purpose of this study was (1) to find out whether preoperative inferior mesenteric artery (IMA) patency (on radiographic imaging) predicts IMA-related endoleaks after endovascular repair of infrarenal abdominal aortic aneurysms, (2) to determine feasibility of measuring aneurysm sac pressures in patients with endoleaks, and (3) to report early evidence of effective endovascular obliteration of IMA endoleaks. Methods: We studied 76 consecutive cases of infrarenal aortic aneurysms that were repaired with an endovascular approach (March 1998–April 1999). Results: There were 13 (17%) endoleaks persistent 30 days after the procedure. Eleven (85%) of these 13 were IMA-related endoleaks, which were documented with selective superior mesenteric artery angiography. The preoperative finding (on computed tomographic scan) of a patent IMA does not always predict an IMA-related endoleak, but results in a statistically and clinically significant higher ratio of patients with IMA-related endoleaks in the immediate postoperative period (24% versus 3%, P <.035). In eight of the 11 patients with persistent IMA-related endoleaks, measurement of intra-aneurysm sac pressures was possible, and six of these patients had systemic pressures within the excluded aneurysm sac. Nine (82%) of 11 IMA-related endoleaks were successfully obliterated by means of selective IMA embolization. Conclusions: Many endoleaks are caused by a patent IMA, and this can result in persistence of systemic pressure within the aneurysm sac. The preoperative finding (on computed tomographic scan) of a patent IMA is a predictor of increased rates of IMA endoleaks, and IMA endoleaks can be successfully obliterated through endovascular procedures, after endovascular abdominal aortic aneurysm repair. (J Vasc Surg 2000;32:777-88.)

The relationship between visceral ischemia, proinflammatory cytokines, and organ injury in patients undergoing thoracoabdominal aortic aneurysm repair.

Plasma proinflammatory, anti-inflammatory cytokine, and soluble tumor necrosis factor (TNF) receptor concentrations were examined in hospitalized patients after abdominal and thoracoabdominal aortic aneurysm (TAAA) repair, with and without left atrial femoral bypass. Changes in plasma cytokine concentrations were related to the duration of visceral ischemia and the frequency rate of postoperative, single, or multiple system organ dysfunction (MSOD). Prospective, observational study. Two academic referral centers in the United States and The Netherlands. We included 16 patients undergoing TAAA repair without left atrial femoral bypass, 12 patients undergoing TAAA repair with left atrial femoral bypass, and nine patients undergoing infrarenal aortic aneurysm repair. Timed, arterial blood sampling for proinflammatory and anti-inflammatory cytokine and soluble TNF receptor concentrations (p55 and p75), and prospective assessment of postoperative single and MSOD. Plasma appearance of TNF-alpha, interleukin (IL)-6, IL-8, and IL-10 peaked 1 to 4 hrs after TAAA repair, and concentrations were significantly elevated compared with infrarenal abdominal aortic aneurysm repair (p < .05). Left atrial femoral bypass significantly reduced the duration of visceral ischemia (p < .05) and the systemic TNF-alpha, p75, and IL-10 responses (p < .05). Plasma TNF-alpha concentrations >150 pg/mL were more common in patients with extended visceral ischemia times (>40 mins). Additionally, patients with early peak TNF-alpha concentrations >150 pg/mL and IL-6 levels >1,000 pg/mL developed MSOD more frequently than patients without these elevated plasma cytokine levels (both p < .05). Thoracoabdominal aortic aneurysm repair results in the increased plasma appearance of TNF-alpha, IL-6, IL-8, IL-10, and shed TNF receptors. The frequency and magnitude of postoperative organ dysfunction after TAAA repair is associated with an increased concentration of the cytokines, TNF-alpha, and IL-6 and the increased plasma levels of these cytokines appear to require extended visceral ischemia times.

Influence of Respiratory Disease on Perioperative Cardiac Risk in Patients Undergoing Elective Surgery for Abdominal Aortic Aneurysm

We retrospectively reviewed perioperative cardiac complications in a series of 214 patients who underwent surgical treatment for infrarenal aortic aneurysm between 1992 and 1996. There were 192 men and 22 women, with a mean age of 68.3 years. Cardiac risk factors included angina in 28% of patients and previous myocardial infarction in 25%. Resting electrocardiography was normal in 80 patients (37.5%). Depending on clinical findings, thallium-201 scintigraphy was undertaken in 76 patients (35.5%) and led to elective coronary arteriography in 22 patients (10%). Results of coronary arteriography revealed lesions in 14 patients. Aortic reconstruction was performed by the transperitoneal route in all patients. Procedures consisted of aortoaortic bypass (63%), aortobiiliac bypass (27.5%), or aortobifemoral bypass (9.5%). Nine patients (4.2%) died within the first 30 postoperative days. The cause of death was myocardial infarction (MI) in two patients (1%), colonic necrosis in two (1%), acute pancreatitis in one (0.5%), acute renal insufficiency in three (1.4%), and multiple organ failure in one patient (0.5%). Nonfatal cardiac complications were observed in 15 patients (7%). Statistical analysis of risk factors revealed two predictors of perioperative cardiac complications, i.e., history of chronic bronchitis and reoperation. On review of the literature, we cannot propose a routine preoperative work-up. Prospective multicentric studies are needed to determine the predictive value of current preoperative screening methods.

In vitro evaluation of the accuracy of open-configuration MRI in endovascular techniques.

The purpose of this study was to determine the accuracy of an interventional magnetic resonance imaging (iMRI) system to position an endovascular catheter in an in vitro model that simulated an infrarenal aortic aneurysm. Adequate visualization of abdominal aortic aneurysms (AAAs) was shown previously in humans. A dedicated near-real-time imaging protocol readily available on a Signa SP 0.5T open configuration MRI unit (General Electric Medical Systems, Milwaukee, WI, USA) was used to image the AAAs of ten human volunteers. A pulsatile in vitro model that simulated an AAA was built, which included the kidneys, the renal arteries, the aorta, and the iliac arteries. A catheter was advanced to a predetermined target through one of the iliac limbs of the model. Using two different techniques, the accuracy with which an interventionist could position the endovascular catheter under the near-real-time guidance of the iMRI system was evaluated. The AAAs of all ten patients were visualized, including the aneurysm wall, the thrombus within it, and the residual lumen, while maintaining adequate contrast, signal, and imaging speed. The position of the catheter was evaluated on target in 42 in vitro procedures. This series of tests showed an average accuracy of 1 mm for catheter positioning. The near-real-time imaging mode of the iMRI system enabled satisfactory evaluation of human AAAs, and it showed great accuracy for catheter positioning in the in vitro model. These results provide optimism regarding the potential of iMRI in endovascular surgery.

An evaluation of the costs to health care institutions of endovascular aortic aneurysm repair

Background: Endovascular graft techniques hold great potential as a less invasive means for the repair of aortic aneurysms, yet the impact of these new modalities remains poorly elucidated. Methods: Over a 10-month period at a single institution, 139 patients underwent infrarenal aortic aneurysm repair through a traditional open surgical technique (OS group, 94 patients) or an endovascular approach (ES group, 45 patients). Coated polyester prostheses (Hemashield; Boston Scientific Corporation, Boston, Mass) were used in the OS patients, whereas a modular nitinol polyester device (AneuRx; Medtronic, Sunnyvale, Calif) was used in the ES group. The hospital costs exclusive of professional charges were tabulated for the two groups using the hospital cost accounting system. Outliers were included in the data analysis. Results: The mean operating room time was longer in the OS group than in the ES group (285 minutes vs 166 minutes). The average length of stay was also longer in the OS group (9.7 days vs 3.2 days). Hospital costs related to the length of stay were higher in the OS group, including laboratory costs ($327 higher), pharmacy costs ($688 higher), and nursing costs ($780 higher). Anesthesia costs were also higher in the OS group ($493 higher). Despite these marked differences, the total hospital cost averaged $7205 more in the ES group, a finding that was driven by the cost of the implantable devices themselves ($8976 in the ES group vs $597 in the OS group). Conclusions: Despite reductions in the length of hospitalization, the cost of care was substantially greater in patients undergoing endovascular aneurysm repair than in patients in whom an open surgical technique was used. These differences are driven by the cost of the endograft device itself, a cost that must not exceed $6000 if the economic impact of endovascular repair is to be in parity with traditional methods. Unless these economic disparities can be ameliorated, the economic impact of endovascular aneurysm repair may limit the widespread application of this technology. (J Vasc Surg 2000;32:148-52.)

SCVIR Annual Meeting Film Panel Session: Diagnosis and Discussion of Case 7

A 74-year-old man underwent Dacron tube graft surgical repair of a large infrarenal aortic aneurysm. Eleven months thereafter, he presented with weight loss, anorexia, and left sciatic pain. Physical examination demonstrated a tender, pulsatile, midabdominal mass. Laboratory studies revealed a leukocytosis of 18,000 L. Images from abdominal computed tomography (CT) (Fig 1) and frontal and lateral abdominal aortography (Fig 2) are presented.

Is Non-specific Aneurysmal Disease of the Infrarenal Aorta Also a Peripheral Microvascular Disease?

Objectives to examine whether aneurysmal disease of the aorta has a functional component in the peripheral microÍvasculature. Materials ten normal persons; and 15 patients who had been operated on for ruptured non-specific infrarenal aortic aneurysm months to years previously were studied. Methods blood flow rates were measured: (a) in the subcutaneous adipose tissue of the forefoot by the133xenon local washout method (perfusion through nutritive capillaries supplied by arterioles with elastin in the tunica media); and (b) in the arteriovenous anastomoses of the pulp of the first toe as measured by the heat washout method (perfusion predominantly through thick-walled tubes without elastin). Perfusion rates were measured in supine subjects at heart level, at 30 cm above and at 30 cm below heart level. Results in subcutaneous adipose tissue, the capillary blood flow rate was four times higher in patients with aneurysmal disease than in normal subjects. Both groups exhibited autoregulation of blood flow and a normal veno-arteriolar sympathetic axon reflex. Blood flow rates in the arteriovenous anastomoses of the pulp did not differ between aneurysm patients and normal subjects. Autoregulation and the axon reflex were absent in the arteriovenous anastomoses of normal subjects as well as in aneurysm patients. Conclusions non-specific aneurysmal disease of the infrarenal aorta has a peripheral functional component affecting arterioles but not arteriovenous anastomoses.

Changing patterns of resident operative experience from 1990 to 1997.

Resident operative experience has increased or decreased with respect to 12 specific operations. A retrospective analysis of resident operative experience reported to the Accreditation Committee for Graduate Medical Education for academic years 1990-1997. Residents completing an Accreditation Committee for Graduate Medical Education surgical program. The total number of residents, average number of operations performed per resident, and the most common operations performed. The number of house staff completing surgical residency training programs has remained constant, while operative volume has increased from 1991 to 1997. Comparison of the frequencies of 12 selected operative procedures performed in academic years 1990-1991 and 1996-1997 found increases in the following procedures: carotid endarterectomy (137%), pancreaticoduodenectomy (66.7%), laparoscopic cholecystectomy (64.8%), parathyroidectomy (51.2%), thyroidectomy (19.2%), colectomy (14.1% to 44.4% depending on subtype), and elective infrarenal aortic aneurysm repair (10.7%). Conversely, frequencies decreased for open cholecystectomy (63.4%), open parietal cell vagotomy (40%), modified radical mastectomy (15.2%), gastroesophageal antireflux procedure (10.4%), and subtotal gastric resection (8.93%). Resident experience was essentially unchanged for emergent infrarenal aortic aneurysm repair and laparoscopic proximal gastric vagotomy. The number and variety of operative interventions in surgical therapeutics is changing. Continued analysis of the operative experience during surgical training will indicate the need for changing requirements for surgical resident experience. The causes of these shifts are not specifically addressed by this study. Perhaps technological advances in the diagnosis and management of surgical patients or the increase in subspecialty training programs have affected the experience of general surgery trainees.