Journal of Endovascular Therapy

To describe a component-based aortomonoiliac stent-graft system and the first clinical results achieved with this device in endovascular abdominal aortic aneurysm (AAA) repair.

From November 1993 to October 1996, 45 patients aged 60 to 86 years underwent endoluminal exclusion of true AAAs (median diameter 60 mm) involving the common iliac arteries (median diameter 16 mm right and 15 mm left) using unilimb stent-grafts deployed with the Ivancev-Malmö system.

Six immediate conversions occurred in the beginning of the series due to endografts that were too short. Complications, including 2 inadvertent renal artery occlusions, 7 kinked grafts, 6 iliac artery dissections, and 3 perioccluder leaks, were prominent features in the first 15 patients. Five patients died in the postoperative period, four of whom were nonsurgical candidates. There were five significant stent-graft migrations: one 3 weeks after surgery due to mechanical injury of the proximal stent and four after 1 year owing to continuous dilation of a wide proximal neck, stent-graft placement in a conical, thrombus-lined proximal neck, and two instances of proximal extension separation from the main graft. Translumbar aneurysm perfusion required embolization in 3 patients.

Despite early complications associated with a learning curve, exclusion of large AAAs using unilimb stent-grafts is feasible. Strict inclusion criteria are necessary in order to improve mortality among nonsurgical candidates and minimize the risk for late migration.

To define the impact of spiral computed tomographic angiography (CTA) with image reconstruction on graft selection for Transfemoral Endovascular Aneurysm Management (TEAM) by comparing it to conventional computed tomography (CT) and contrast arteriography.

Twenty-one candidates for TEAM were included. The diameters of the superior and inferior aneurysm necks and lengths between the graft attachment sites were measured using the three imaging techniques. These measurements and their consequences on graft selection were studied.

The difference in length sizing between spiral CTA and arteriography never exceeded 1 cm; however, lengths measured by conventional CT scanning resulted in underestimation of graft length in 91% of patients. Graft diameters were chosen too small in 62% of the patients when based on arteriographic diameter measurements. A graft of similar diameter was selected by spiral CTA and conventional CT scanning in 81% of the patients, while minor oversizing by conventional CT scanning was found in 14%.

Neither conventional CT scanning nor arteriography is adequate as a sole preoperative radiological investigation for TEAM graft sizing. Spiral CTA with image processing produces all information required for selection of tho-optimal graft size and should be regarded the method of first choice for this purpose.

To report the feasibility and sensitivity of duplex sonography compared to computed tomography (CT) for aortic endograft follow-up surveillance.

In a 26-month period, 113 aortic aneurysm patients received 79 tube and 34 bifurcated stent-grafts. Follow-up used contrast-enhanced CT scanning and duplex sonography with an intravenous ultrasound contrast agent (Levovist).

Eleven patients (9.7%) were converted to open repair; 1 died from hemorrhagic shock secondary to retroperitoneal hematoma. The mean follow-up time was 7.2 months (range 1 to 24), during which 5 patients died of unrelated causes.

Sixteen primary (within 30 days) and 5 secondary endoleaks were detected by duplex after tube graft implantation. Among 5 endoleaks due to retrograde side-branch perfusion, 3 were detected only with contrast-enhanced duplex scanning. Iliac artery occlusion was also documented using duplex; however, 2 stent fractures could not be seen with ultrasound.

Ten primary endoleaks were detected in bifurcated stent-graft patients. One endoleak originating from the distal iliac limb anchoring site was missed by duplex owing to bowel gas. Graft limb thrombosis was clearly identified by lack of a flow signal on duplex.

Duplex sonography could be a valuable, reliable, and economical surveillance tool for endovascular aortic reconstructions. The adjunctive use of an intravenous ultrasound contrast agent increased the sensitivity for detecting endoleak to a level comparable to contrast-enhanced CT scanning. However, stent fractures may not be seen on ultrasound, and bowel gas can interfere with obtaining an adequate image.

To evaluate different ultrasound modalities during implantation and follow-up of endovascular grafts for abdominal aortic aneurysm (AAA) exclusion.

Between February 1995 and May 1996, 18 patients (14 men; aged 49 to 80 years, mean 67) were treated with endovascular intervention for infrarenal AAA. Seventeen patients received Mialhe Stentor bifurcated grafts, while one patient was treated with a straight graft for pseudoaneurysm. During and after the implantation, 3.25- and 5-MHz annular array ultrasound probes were used for transabdominal visualization of the endograft. Intravascular ultrasound was applied in combination with angiography for postoperative control.

Intraprocedurally, transabdominal two-dimensional (2D) ultrasound successfully monitored guidewire passage from the groin into the main part of the bifurcated endograft for implantation of the second limb. All implantation procedures were technically successful, but four endoleaks were identified intraprocedurally by 2D ultrasound and angiography. One healed spontaneously, two were treated with endovascular techniques at 1 and 4 months, and the last leak was scheduled for repair when the patient died of probable myocardial infarction at 2 months. During follow-up, 2D ultrasound successfully visualized all the endografts; no endoleaks were found in up to 18 months of surveillance.

Transabdominal ultrasound imaging could be valuable in bifurcated endograft deployment both for guiding guidewire insertion and for controlling wire position before the second graft limb is connected to the main graft. Provided that satisfactory visualization of the entire endograft can be obtained, ultrasound examination may possibly replace arteriography and computed tomographic scanning as a follow-up investigation.

To assess the effect of abdominal aortic aneurysm (AAA) size on overall aneurysm morphology with special attention to possible relationships among various anatomic variables that determine the feasibility of endovascular repair.

One hundred sixty-eight patients were assessed with spiral computed tomographic angiography to measure the length and diameter of the AAA, the proximal neck, and the common iliac arteries. Anatomic variables were correlated with aneurysm size using Spearman's rank order correlation coefficients (r_s); comparisons among small, intermediate, and large aneurysms were made using the Chi-square test.

Correlations between aneurysm size and the anatomic variables above were weak. The strongest association was between aneurysm size and aortic length (r_s = 0.41, p < 0.001). Subgroup analysis showed no difference in proximal neck length, neck diameter, or overall suitability for endovascular repair between aneurysms greater or smaller than 5.5-cm diameter. However, significantly more short (< 1.5 cm), wide (> 3 cm), and, hence, unsuitable proximal necks were found in patients with aneurysms > 7 cm in diameter (χ² = 7.8, p < 0.01).

Shortening and widening of the proximal neck seems to increase with aneurysm size but only after the aneurysm expands beyond 7 cm in diameter. Aneurysms with diameters in the 4.5- to 5.5-cm range are no more suitable for endovascular repair than those between 5.5 and 7 cm. The lack of any significant correlation between anatomic variables emphasizes the need for accurate preoperative assessment of the anatomy of each individual patient before endovascular repair.

To investigate the feasibility of using predilated thin-wall polytetrafluoroethylene (PTFE) secured by extra-large Palmaz stents for endoluminal repair of abdominal aortic aneurysms (AAA).

Thirty-two patients (26 males; aged 69 to 83 years) from three centers (two in Europe, one in Australia) were selected for endoluminal stent-grafting using predilated 8-mm PTFE graft material fitted with extra-large Palmaz stents at the terminal ends. Aortoaortic tube grafts were implanted in 12 patients, while the remainder received aortomonoiliac endografts and femorofemoral bypass. Follow-up at 5 days and then biannually was by contrast-enhanced computed tomography (CT) or duplex scanning.

There were 13 conversions to open surgery; three patients died within 30 days. Nineteen patients were discharged with functioning endografts within 5 days of treatment. Of these, two have had their grafts removed owing to infection in one and distal stent migration in the other. Two endoleaks have been detected in follow-up; one has been sealed by covered stenting. One twisted graft was repaired by Wallstent implantation. Seventeen patients remain well, one with persistent distal endoleak, but none shows an increase in AAA diameter on imaging over the 6- to 26-month (median 13) follow-up.

These results represent the learning curves of three separate centers. Technical failure and complications were more common early in the study. Advantages of the technique include relative low cost and the ability to tailor the stent-graft to the individual aneurysm.

To develop an animal model for the acute and chronic monitoring of pressure within abdominal aortic aneurysms (AAAs) to be treated with endovascular grafts.

A strain-gauge pressure transducer was placed within an AAA created from a prosthetic vascular graft. Prosthetic aneurysms were implanted into 17 canine infrarenal aortas. The intra-aneurysmal pressure was monitored and correlated with noninvasive forelimb sphygmomanometry for 2 weeks. After this time, an intravascular manometer catheter was passed into the aneurysm. Simultaneous pressure measurements were obtained using the implanted strain-gauge pressure transducer, the manometer catheter, and the forelimb sphygmomanometer. Angiography was performed to assess intraluminal morphology, aneurysm anastomoses, and adjoining aortic vessels. In addition, two control animals underwent intra-aneurysmal pressure monitoring after standard surgical aneurysm repair.

There was excellent correlation (r = 0.97) between the pressure measurements obtained with the implanted strain-gauge pressure transducer and the intravascular manometer. Close correlation was also observed between the implanted strain-gauge transducer and the forelimb sphygmomanometer (r = 0.88) during postprocedural monitoring. Intra-aneurysmal pressure was lowered dramatically by surgical exclusion (aneurysm: 15/5 ± 7/4 mmHg; systemic: 124/66 ± 34/17 mmHg; p < 0.001). The prosthetic aneurysms were successfully imaged with angiography.

This animal model provides an accurate and reproducible means for measuring intra-aneurysmal pressure on an acute and chronic basis. It may be possible to use this model in the assessment of endovascular devices to determine their efficacy in reducing intra-aneurysmal pressure. Evaluation of complications associated with their use, such as patent aneurysm side branches, perigraft channels, and perianastomotic reflux, may also be possible.

To report the outcome of the prospective 11-center Italian Parodi Trial using straight and tapered endografts for the endovascular exclusion of abdominal aortic aneurysms (AAA).

From April 1994 to July 1995, 27 patients were evaluated and selected for endovascular AAA exclusion. The Parodi devices were delivered through femoral arteriotomies using 18 to 22F introducers and deployed by balloon expansion of the terminal stents.

Of 27 cases attempted, 24 endografts (15 tube, 9 aortomonoiliac) were implanted (1 deployment and 2 access failures [11.1%] were converted). Three endoleaks (12.5%) were treated intraoperatively with covered stents, two successfully, and the third sealed within 30 days.

Three (12.5%) of the 24 treated patients died in-hospital of device- (n = 2) and procedure-related (n = 1) causes; the remaining 21 patients were discharged within 8 days. Of the 8 aortomonoiliac grafts in follow-up, only 1 (12.5%) failed in the mean 23-month (range 18 to 30) follow-up; however, 4 (31%) of 13 tube graft patients were converted to surgery within 18 months. Of the 16 (66.7%) surviving endografts at 2 years, 6 (38%) showed no change in the AAA diameter, while 10 (62%) had shrunk.

The tube graft was applicable in only about 5% of cases, and accurate endograft sizing and distal fixation were problematic. The aortomonoiliac design was not appealing to surgeons but fared better in the long term. Given the advent of newer endograft models, the Italian Parodi Trial has been terminated.

To explore a method of combined endovascular/conventional treatment of abdominal aortic aneurysm (AAA), in which the iliac arteries are reconstructed by conventional surgical techniques to provide the anatomic substrate for subsequent endovascular repair of the aortic aneurysm.

A 77-year-old patient with severe cardiac disease was found to have a 6.5-cm AAA, bilateral common iliac artery (CIA) aneurysms, and diffusely narrowed, tortuous external iliac arteries. The left internal iliac artery was occluded. At operation, the right CIA was exposed through a transverse retroperitoneal incision under epidural anesthesia. An iliobifemoral bypass was constructed using a preformed bifurcated graft.

A stent-graft was delivered through the right limb of the bifurcated iliobifemoral graft. The proximal end of the stent-graft was implanted in the neck of the aneurysm, and the distal end was deployed in the common trunk of the iliobifemoral graft, thereby excluding the AAA and both native iliac arteries from prograde arterial flow.

Completion angiography and follow-up contrast computed tomography showed the aneurysm to be excluded from the circulation. The patient was not intubated, was never hemodynamically unstable, and had aortic blood flow interrupted for no more than 20 seconds. In addition, he was able to resume his usual diet on the first postoperative day. He continues to be well and without evidence of endoleak at 6-month follow-up.

This case demonstrates that iliac artery stenosis, tortuosity, and aneurysmal dilatation are not impediments to endovascular AAA exclusion. Any necessary surgical modifications of pelvic arterial anatomy can be performed before stent-graft insertion to minimize aortic occlusion time.

To report the successful endovascular occlusion of a persistent endoleak owing to collateral perfusion in a 1-year-old bifurcated aortic endograft.

An 81-year-old man underwent endovascular repair of a 5.5-cm abdominal aortic aneurysm (AAA) with a bifurcated stent-graft in 1995; collateral perfusion of the excluded aneurysm by retrograde filling of the patent inferior mesenteric artery (IMA) was noted postoperatively. At his 1-year follow-up, the mid-sac endoleak persisted on contrast-enhanced computed tomography. Using the superior mesenteric artery for access, the stump of the IMA was successfully embolized with glue.

This case, which highlights the importance of documenting a patent IMA prior to AAA endografting, illustrates one option for the management of persistent collateral perfusion of endovascularly excluded aneurysms.