Survival and Reintervention Risk by Patient Age and Preoperative Abdominal Aortic Aneurysm Diameter after Endovascular Aneurysm Repair.

BACKGROUND: Endovascular aneurysm repair (EVAR) has become the standard of care for abdominal aortic aneurysm (AAA), but questions remain regarding the benefit in high-risk and elderly patients. The purpose of this study was to examine the effect of age, preoperative AAA diameter, and their interaction on survival and reintervention rates after EVAR. METHODS: Our integrated health system's AAA endograft registry was used to identify patients who underwent elective EVAR between 2010 and 2014. Of interest was the effect of patient age at the time of surgery (≤80 vs. >80 years old), preoperative AAA diameter (≤5.5 cm vs. >5.5 cm), and their interaction. Primary endpoints were all-cause mortality and reintervention. Between-within mixed-effects Cox models with propensity score weights were fit. RESULTS: Of 1,967 patients undergoing EVAR, unadjusted rates for survival at 4 years after EVAR was 76.1%, and reintervention-free rate was 86.0%. For mortality, there was insufficient evidence for an interaction between age and AAA size (P = 0.309). Patient age >80 years was associated with 2.53-fold higher mortality risk (hazard ratios [HR] = 2.53; 95% confidence intervals [CI], 1.73-3.70; P < 0.001), whereas AAA > 5.5 cm was associated with 1.75-fold higher mortality risk (HR = 1.75; 95% CI, 1.26-2.45; P = 0.001). For reintervention risk, there were no significant interactions or main effects for age or AAA diameter. CONCLUSIONS: Age and AAA diameter are independent predictors of reduced survival after EVAR, but the effect is not amplified when both are present. Age >80 years or AAA size >5.5 cm did not increase the risk of reintervention. No specific AAA size, patient age, or combination thereof was identified that would contraindicate AAA repair.

A multiregional registry experience using an electronic medical record to optimize data capture for longitudinal outcomes in endovascular abdominal aortic aneurysm repair.

OBJECTIVE: Registries have been proven useful to assess clinical outcomes, but data entry and personnel expenses are challenging. We developed a registry to track patients undergoing endovascular aortic aneurysm repair (EVAR) in an integrated health care system, leveraging an electronic medical record (EMR) to evaluate clinical practices, device performance, surgical complications, and medium-term outcomes. This study describes the registry design, data collection, outcomes validation, and ongoing surveillance, highlighting the unique integration with the EMR. METHODS: EVARs in six geographic regions of Kaiser Permanente were entered in the registry. Cases were imported using a screening algorithm of inpatient codes applied to the EMR. Standard note templates containing data fields were used for surgeons to enter preoperative, postoperative, and operative data as part of normal workflows in the operating room and clinics. Clinical content experts reviewed cases and entered any missing data of operative details. Patient comorbidities, aneurysm characteristics, implant details, and surgical outcomes were captured. Patients entered in the registry are followed up for life, and all relevant events are captured. RESULTS: Between January 2010 and June 2013, 2112 procedures were entered in the registry. Surgeon compliance with data entry ranges from 60% to 90% by region but has steadily increased over time. Mean aneurysm size was 5.9 cm (standard deviation, 1.3). Most patients were male (84%), were hypertensive (69%), or had a smoking history (79%). The overall reintervention rate was 10.8%: conversion to open repair (0.9%), EVAR revision (2.6%), other surgical intervention (7.3%). Of the reinterventions, 27% were for endoleaks (I, 34.3%; II, 56.9%; III, 8.8%; IV and V, 0.0%), 10.5% were due to graft malfunction, 3.4% were due to infection, and 2.3% were due to rupture. CONCLUSIONS: Leveraging an EMR provides a robust platform for monitoring short-term and midterm outcomes after abdominal aortic aneurysm repair. Use of standardized templates in the EMR allows data entry as part of normal workflow, improving compliance, accuracy, and data capture using limited but expert personnel. Assessment of patient demographics, device performance, practice variation, and postoperative outcomes benefits clinical decision-making by providing complete and adjudicated event reporting. The findings from this large, community-based EVAR registry augment other studies limited to perioperative and short-term outcomes or small patient cohorts.

No increased mortality with early aortic aneurysm disease.

OBJECTIVE: In addition to increased risks for aneurysm-related death, previous studies have determined that all-cause mortality in abdominal aortic aneurysm (AAA) patients is excessive and equivalent to that associated with coronary heart disease. These studies largely preceded the current era of coronary heart disease risk factor management, however, and no recent study has examined contemporary mortality associated with early AAA disease (aneurysm diameter between 3 and 5 cm). As part of an ongoing natural history study of AAA, we report the mortality risk associated with presence of early disease. METHODS: Participants were recruited from three distinct health care systems in Northern California between 2006 and 2011. Aneurysm diameter, demographic information, comorbidities, medication history, and plasma for biomarker analysis were collected at study entry. Survival status was determined at follow-up. Data were analyzed with t-tests or χ(2) tests where appropriate. Freedom from death was calculated via Cox proportional hazards modeling; the relevance of individual predictors on mortality was determined by log-rank test. RESULTS: The study enrolled 634 AAA patients; age 76.4 ± 8.0 years, aortic diameter 3.86 ± 0.7 cm. Participants were mostly male (88.8%), not current smokers (81.6%), and taking statins (76.7%). Mean follow-up was 2.1 ± 1.0 years. Estimated 1- and 3-year survival was 98.2% and 90.9%, respectively. Factors independently associated with mortality included larger aneurysm size (hazard ratio, 2.12; 95% confidence interval, 1.26-3.57 for diameter >4.0 cm) and diabetes (hazard ratio, 2.24; 95% confidence interval, 1.12-4.47). After adjusting for patient-level factors, health care system independently predicted mortality. CONCLUSIONS: Contemporary all-cause mortality for patients with early AAA disease is lower than that previously reported. Further research is warranted to determine important factors that contribute to improved survival in early AAA disease.

Keyhole technique for autologous brachiobasilic transposition arteriovenous fistula.

BACKGROUND: Autologous brachiobasilic transposition arteriovenous fistulas (AVFs) are desirable but require long incisions and extensive surgical dissection. To minimize the extent of surgery, we developed a catheter-based technique that requires only keyhole incisions and local anesthesia. METHODS: The technique involves exposure and division of the basilic vein at the elbow. A guidewire is introduced into the vein, and a 6F "push catheter" is advanced over the guidewire and attached to the vein with sutures. Gently pushing the catheter proximally inverts, or intussuscepts, the vein. Side branches that are felt as resistances when pushing the catheter forward are localized, clipped, and divided under direct vision. Throughout the procedure, the endothelium always remains intraluminal. The basilic vein is externalized at the axilla without dividing it proximally and is tunneled subcutaneously, where it is anastomosed to the brachial artery. RESULTS: Thirty-two patients underwent the procedure--31 as outpatients. The mean duration of operation was less than 90 minutes. All patients tolerated the procedure well, and 31 required only intravenous sedation and local anesthesia. At a mean follow-up of 8 months, the primary patency rate of AVFs in patients with basilic vein diameters of 4 mm or more on preoperative duplex ultrasonography was 80%, vs 50% for those with vein diameters less than 4 mm. Overall, 78% of patent AVFs were being successfully accessed and 22% were still maturing at last follow-up. CONCLUSIONS: Autologous brachiobasilic transposition AVFs can be created by using catheter-mediated techniques that facilitate the mobilization and tunneling of the basilic vein through small incisions. Medium-term data suggest that the inversion method results in acceptable maturation and functionality of AVFs created with this technique.

"Over-the-wire" inversion saphenectomy: a simple, minimally invasive vein harvesting technique for arterial bypass.

PURPOSE: To examine the feasibility and clinical outcome of a novel, minimally invasive technique for harvesting the great saphenous vein (GSV) for use in peripheral arterial bypass surgery. METHODS: Between May 2001 through March 2003, 27 patients (15 men; mean age 71+/-10 years) underwent extremity bypass procedures for limb salvage (88%) or disabling claudication (12%) using the inversion technique to harvest the GSV. The veins were turned "inside out" using a unique catheter and guidewire system. With the endothelial surface exposed, valve leaflets were excised, and adherent thrombus was washed away. Veins were inverted again to turn the endothelial surface back inside the lumen for use as a bypass conduit. RESULTS: Inversion vein harvesting and arterial bypass were completed in 24 (89%) of 27 patients; 2 patients were treated with synthetic grafts because of small GSVs. Another patient was found after vein harvesting to have inadequate arterial outflow despite a good quality conduit. The average vein length was 45+/-10 cm; a mean 4+/-1 incisions were made, including those for arterial exposure. Incisions made to divide vein tributaries averaged 2 cm in length. Duration of vein harvesting was 25 minutes (range 5-80). Wound complications were minor (2 hematomas, 2 cases of erythema, 2 seromas). Of 6 grafts that occluded after 30 days, 5 involved small-diameter vein grafts (< 3.5 mm). At a mean 12 months, primary and assisted primary graft patency rates were 88% (14/16) and 94% (15/ 16), respectively, for grafts with minimum diameters > or = 4 mm versus 38% (3/8) primary patency for veins < 4 mm (n = 8, p < 0.001). The limb salvage rate was 92% (22/24). CONCLUSIONS: Over-the-wire inversion saphenectomy is a simple and reliable minimally invasive technique for arterial bypass. Incisions are small and cosmetically superior to those of the traditional long incision method. One-year follow-up suggests that grafts harvested by inversion technique have excellent durability when the minimum vein diameter is > or = 4 mm, as determined by preoperative vein mapping.

Hypogastric artery bypass to preserve pelvic circulation: improved outcome after endovascular abdominal aortic aneurysm repair.

OBJECTIVE: This study was carried out to compare the functional outcomes after hypogastric artery bypass and coil embolization for management of common iliac artery aneurysms in the endovascular repair of aortoiliac aneurysms (EVAR). METHODS: Between 1996 and 2002, 265 patients underwent elective or emergent EVAR. Data were retrospectively reviewed for 21 (8%) patients with iliac artery aneurysms 25 mm or larger that involved the iliac bifurcation. Patients underwent hypogastric artery bypass (n = 9) or coil embolization (n = 12). Interviews about past and current levels of activity were conducted. A disability score (DS) was quantitatively graded on a discrete scale ranging from 0 to 10, corresponding to "virtually bed-bound" to exercise tolerance "greater than a mile." Worsening or improvement of symptoms was expressed as a difference in DS between two time points (-, worsening; +, improvement). RESULTS: There was no difference in age (72.6 +/- 7.3 years vs 73.1 +/- 6.4 years), sex (male-female ratio, 8:1 vs 11:1), abdominal aortic aneurysm size (60.1 +/- 5.9 mm vs 59.3 +/- 7.0 mm), or number of preoperative comorbid conditions (1.9 +/- 0.8 vs 2.1 +/- 0.8) between hypogastric bypass and coil embolization groups, respectively. Mean follow-up was shorter after hypogastric bypass (14.8 vs 20.5 months; P <.05). There was no difference in the mean overall baseline DS between the bypass and the embolization groups (8.0 vs 7.8). Six (50%) of the 12 patients with coil embolization reported symptoms of buttock claudication ipsilateral to the occluded hypogastric artery. No symptoms of buttock claudication were reported after hypogastric bypass (P <.05). There was a decrease in the DS after both procedures; however, coil embolization was associated with a significantly worse DS compared with hypogastric artery bypass (4.5 vs 7.3; P <.001). In 4 (67%) of 6 patients with claudication after coil embolization symptoms improved, with a DS of 5.4 at last follow-up. This was significantly worse than in patients undergoing hypogastric artery bypass, with a DS of 7.8 at last follow-up (P <.001). There was no difference between the groups in duration of procedure, blood loss, length of hospital stay, morbidity, or mortality (0%). CONCLUSIONS: Hypogastric artery bypass to preserve pelvic circulation is safe, and significantly decreases the risk for buttock claudication. Preservation of pelvic circulation results in significant improvement in the ambulatory status of patients with common iliac artery aneurysms, compared with coil embolization.

Morphologic changes and outcome following endovascular abdominal aortic aneurysm repair as a function of aneurysm size.

HYPOTHESIS: Small infrarenal abdominal aortic aneurysms have a more favorable clinical and morphologic outcome compared with medium and large abdominal aortic aneurysms following endovascular aneurysm repair(EVAR). DESIGN: A prospective clinical series of 206 patients undergoing elective EVAR between 1996 and 2001. SETTING: A tertiary care academic health center. PATIENTS: Patients were grouped according to aneurysm size: small (<50 mm), medium (50-60 mm), and large (>60 mm). INTERVENTIONS: Primary EVAR and secondary procedures to secure fixation of the stent graft and surgical conversions. MAIN OUTCOME MEASURES: Aneurysm diameter, endoleaks, and long-term morphologic changes were analyzed postoperatively with 3-dimensional reconstructions of computed tomographic angiograms. RESULTS: Groups were similar in age, comorbidities, and follow-up (mean +/- SD, 32.1 +/- 11.8 months). There were 30 small aneurysms, 92 medium aneurysms, and 84 large aneurysms, with a mean size of 45.1 +/- 3.7 mm, 53.8 +/- 3.1 mm, and 66.1 +/- 6.8 mm, respectively (P<.01). There was no significant difference in proximal neck or iliac artery diameter among the 3 groups. The proximal aortic neck length (28.1 +/- 11.6 mm [small]; 23.9 +/- 11.3 mm [medium]; and 22.1 +/- 11.6 mm [large]; P<.05) was significantly shorter in large aneurysms. Furthermore, there was a significant increase (6% [small]; 15% [medium]; and 21% [large]; P<.05) in angulated necks in large aneurysms. Following treatment, aneurysm diameter remained stable in most patients (83% [small]; 82% [medium]; and 83% [large]), with a mean decrease of 2.0 +/- 6.5 mm, 2.1 +/- 6.1 mm, and 3.7 +/- 7.7 mm in each group, respectively (P =.45). There was no difference in the incidence of endoleaks, aneurysm contraction, or aneurysm expansion based on preoperative aneurysm diameter. Secondary procedures were performed in 5 (20%) of 25, 9 (5.2%) of 170, and 5 (36%) of 11 aneurysms that contracted, remained stable, or expanded, respectively, following EVAR (P<.05). CONCLUSIONS: There is a 15% increase in neck angulation and a 27% decrease in neck length in large compared with small infrarenal abdominal aortic aneurysms, with no difference in outcome. Aneurysms that are stable following EVAR have a significantly lower incidence of requiring secondary procedures.

Early and late functional outcome assessments following endovascular and open aneurysm repair.

PURPOSE: To compare early and late functional outcomes, as well as survival and recovery, following endovascular or open repair of abdominal aortic aneurysm (AAA). METHODS: Between 1996 and 2000, 294 patients underwent AAA repair (141 open and 153 endovascular); 57 patients from each group had 12-month follow-up for functional outcome assessment. Recovery was measured as hospital length of stay, skilled nursing requirement, and hospital readmission within 1 year to determine cumulative hospital utilization. Early (<6 months) functional outcomes were measured by activity level and convalescence days following surgery. Late (>6 months) functional outcomes were measured as ambulation, independent living, and employment status pre- and postoperatively. RESULTS: Operative mortality for open repair was 5 (3.5%) compared to 1 (0.6%) after an endovascular procedure (p<0.05). The endovascular group had a shorter hospital stay (2.8+/-2.8 versus 8.3+/-4.5 days) and fewer skilled nursing requirements (0% versus 26%; p<0.001). Cumulative hospital utilization over 12 months was 3.8 days for endovascular patients and 13.8 days for open repair (p<0.001). Recovery time was 99.3+/-84.1 days (range 14-365) in conventionally treated patients and 32.1+/-43.5 days (range 7-180) in the stent-graft group (p<0.001). At 6 months, 43 (75%) open and 54 (95%) endovascular patients had full recovery (p<0.01). Activity levels decreased in 13 (23%) open and 3 (5%) endovascular patients after surgery (p<0.01). There were no differences in ambulation, independent living, or employment status before and after treatment. CONCLUSIONS: Periprocedural survival following aneurysm repair is improved with endovascular grafting compared to open surgery, and recovery is more rapid, with a 78% reduction in total hospital days. Early functional outcomes are markedly improved with endovascular repair, while there is no difference in late functional outcomes between the procedures.

Aneurysm-related death: primary endpoint analysis for comparison of open and endovascular repair.

PURPOSE: The purpose of this study was to utilize an objective endpoint analysis of aneurysm treatment, which is based on the primary objective of aneurysm repair, and to apply it to a consecutive series of patients undergoing open and endovascular repair. METHOD: Aneurysm-related death was defined as any death that occurred within 30 days of primary aneurysm treatment (open or endovascular), within 30 days of a secondary aneurysm or graft-related treatment, or any death related to the aneurysm or graft at any time following treatment. We reviewed 417 consecutive patients undergoing elective infrarenal aortic aneurysm repair: 243 patients with open repair and 174 patients with endovascular repair. RESULTS: There was no difference between the groups (open vs endovascular) with regard to mean age +/- standard deviation (73 +/- 8 years vs 74 +/- 8 years) or aneurysm size (64 +/- 2 mm vs 58 +/- 10 mm) (P = not significant [NS]). The 30-day mortality for the primary procedure after open repair was 3.7% (9/243) and after endovascular repair was 0.6% (1/174, P <.05). The 30-day mortality for secondary procedures after open repair was 14% (6/41) compared to 0% after endovascular repair (P <.05). The aneurysm-related death rate was 4.1% (10/243) after open surgery and 0.6% (1/174) after endovascular repair (P <.05). Mean follow-up was 5 months longer following open repair (P <.05). Secondary procedures were performed in 41 patients following open surgery and 27 patients following endovascular repair (P = NS). Secondary procedures following open repair were performed for anastomotic aneurysms (n = 18), graft infection (n = 6), aortoenteric fistula (n = 5), anastomotic hemorrhage (n = 4), lower extremity amputation (n = 4), graft thrombosis (n = 3), and distal revascularization (n = 1). Secondary procedures following endovascular repair consisted of proximal extender cuffs (n = 11), distal extender cuffs (n = 11), limb thrombosis (n = 3), and surgical conversion (n = 2). The magnitude of secondary procedures following open repair was greater with longer operative time 292 +/- 89 minutes vs 129 +/- 33 minutes (P <.0001), longer length of stay 13 +/- 10 days vs 2 +/- 2 days (P <.0001) and greater blood loss 3382 +/- 4278 mL vs 851 +/- 114 mL (P <.0001). CONCLUSIONS: The aneurysm-related death rate combines early and late deaths and should be used as the primary outcome measure to objectively compare the results of open and endovascular repair in the treatment of infrarenal abdominal aortic aneurysms. In our experience, endovascular aneurysm repair reduced the overall aneurysm-related death rate when compared to open repair. Secondary procedures are required after both open and endovascular repair. However, the magnitude, morbidity, and mortality of secondary procedures are reduced significantly with endovascular repair.

Open versus endovascular AAA repair in patients who are morphological candidates for endovascular treatment.

PURPOSE: To compare the outcomes of open versus endovascular repair of abdominal aortic aneurysm (AAA) in a cohort of patients who fulfill morphological criteria for endovascular repair. METHODS: A retrospective review of 229 consecutive AAA patients treated over a 3-year period identified 149 patients who were candidates for endovascular repair based on preoperative computed tomography and angiography. Of the 149 patients, 79 (68 men; mean age 74 +/- 8 years) underwent endovascular repair with the AneuRx stent-graft; the remaining 70 (56 men; mean age 72 +/- 8 years) had open repair. Short-term outcome measures were 30-day mortality and procedure-related morbidity, length of stay in the intensive care unit and hospital, intraoperative blood loss, interval to oral diet, and time to ambulation. Long-term outcome measures included death and secondary procedures. RESULTS: There was no difference in the 30-day mortality between endovascular repair (2, 2.5%) and open repair (2, 2.9%), even though endovascular patients had more comorbidities (p<0.05). Overall length of stay was reduced for endovascular patients (3.9 +/- 2.4 days versus 7.7 +/- 3.1 days for surgical patients, p<0.0001). Fewer endograft patients had complications (24% versus 40% for open repair, p<0.05), and the severity of these complications was less, as evidenced by the shorter hospital stays for endovascular patients with complications compared to conventionally treated patients with complications (6.7 +/- 2.4 days versus 22.5 +/- 35.2 days, p<0.05). There were no aneurysm ruptures or late surgical conversions in either group. CONCLUSIONS: Patients with AAA who were endograft candidates but who were treated with open repair experienced more morbidity and had more complications than patients treated with stent-grafts. Despite increased comorbidities in the endograft patients, there was no increase in mortality compared to open repair. Both treatments required secondary procedures and appeared to be equally effective in preventing aneurysm rupture up to 3 years.

The first 150 endovascular AAA repairs at a single institution: how steep is the learning curve?

PURPOSE: To determine whether increasing experience with endovascular abdominal aortic aneurysm (AAA) repair in a single institution will result in improved outcome. METHODS: A retrospective review was undertaken of 150 consecutive cases of endovascular AAA repairs performed using the AneuRx device between October 1996 and April 2000 in a university-based medical center. The population was divided into early and late groups of 75 patients each. Endpoints included technical success; complications; early (< or =30-day) morbidity, mortality and rupture; endoleak at discharge and at 1 month; early secondary intervention; proximal neck and iliac tortuosity; extender cuff placement; femoral reconstructions beyond primary repair; total fluoroscopy time; and contrast load. RESULTS: Baseline patient and aneurysm characteristics were similar between the 2 groups. Technical success was 98.7%; 2 cases were converted intraprocedurally owing to difficult iliac access (early group) and a severely angulated proximal neck (late group). There was a tendency toward more frequent use of intraoperative proximal extender cuffs in the early group (12% versus 4% in the late group, p=0.13). Femoral reconstructions were more frequent in the early group (36% versus 19%, p<0.025). While total contrast volume was similar (111 +/- 56 versus 105 +/- 45 mL, p=NS), total fluoroscopy time was significantly reduced (p<0.05) between the early and late groups. CONCLUSION: With attention to detail and careful patient selection, successful endovascular AAA repair can be achieved with very few conversions and low perioperative mortality even during the center's early experience. Evidence indicates, however, that a learning curve definitely exists, as shown by fewer access site problems, more accurate device deployments, and decreased fluoroscopy times as proficiency is attained.

Gender differences in endovascular abdominal aortic aneurysm repair with the AneuRx stent graft.

OBJECTIVE: The objective of this study was to evaluate gender differences in the selection, procedure, and outcome of endovascular abdominal aortic aneurysm repair (EVAR). PATIENTS: Between October 1996 and January 2001, 378 patients were evaluated for EVAR and 189 patients underwent EVAR with the Medtronic AneuRx stent graft at a single center. RESULTS: Women constituted 17% of patients considered for EVAR. Their eligibility rate (49%) did not differ significantly from that of men (57%), and they constituted 14% of patients who underwent EVAR (26/189). Women who underwent EVAR were older (77.9 +/- 6.3 years versus 73.1 +/- 8.1 years; P <.005) with a higher rate of chronic obstructive lung disease (50% versus 28%; P <.05). Maximal aneurysm diameter (57.2 +/- 10.9 mm versus 57.8 +/- 9.4 mm; not significant) did not differ between men and women. Mean diameters of the proximal neck (20.4 +/- 2.3 mm versus 22.3 +/- 2.0 mm; P <.01), common iliac arteries (11.4 +/- 1.2 mm versus 13.5 +/- 3.6 mm; P <.001), and external iliac arteries (7.9 +/- 0.7 mm versus 9.4 +/- 1.4 mm; P <.001) were all smaller in women, and abdominal aortic aneurysm/neck diameter ratio was larger (2.82 +/- 0.59 versus 2.60 +/- 0.49; P <.05). The length of the proximal aortic neck was shorter in women (20.7 +/- 8.2 mm versus 24.5 +/- 11.8 mm; P <.05). Women had significantly more intraoperative complications (31% versus 13%; P <.05), primarily related to arterial access, and needed more frequent arterial reconstruction (42% versus 21%; P <.05), without a difference in postoperative mortality rate (0/26 versus 2/163; not significant) and complication rate (23% versus 20%: not significant). During a follow-up period of 13.8 +/- 11.7 months, no gender-related difference was found in survival rate, endoleak rate, or reintervention rate or in the rate of change in aneurysm diameter or volume. CONCLUSION: Eligibility rates of women for EVAR are similar to those of men. Women are at an increased risk for access-related complications during EVAR, but outcome is equivalent to that of men.

Noninvasive measurement of extraction fraction and single-kidney glomerular filtration rate with MR imaging in swine with surgically created renal arterial stenoses.

PURPOSE: To test whether magnetic resonance (MR) imaging enables accurate measurement of extraction fraction (EF) in swine with unilateral renal ischemia and to evaluate effects of renal arterial stenosis on EF and single-kidney glomerular filtration rate. MATERIALS AND METHODS: High-grade unilateral renal arterial stenoses were surgically created in eight pigs. Direct measurements of renal venous and arterial inulin concentration provided reference standard estimates of single-kidney EF. Pigs were imaged with a 1.5-T imager to estimate EF, renal blood flow, and glomerular filtration rate. A breath-hold inversion-recovery spiral sequence was used to measure T1 of blood in the infrarenal inferior vena cava and renal veins after intravenous administration of gadopentetate dimeglumine, and these data were used to calculate EF. Cine-phase contrast material-enhanced imaging of the renal arteries provided quantitative renal blood flow measurements. Bilateral single-kidney glomerular filtration rate was then determined: glomerular filtration rate = renal blood flow x (1 - hematocrit level) x EF. RESULTS: A statistically significant linear correlation was found between EF, as determined with MR imaging, and inulin (r = 0.77). As compared with kidneys without renal arterial stenosis, kidneys with renal arterial stenosis showed 50% (0.14/0.28) EF reduction (P <.01) and 59% glomerular filtration rate reduction (P <.01). CONCLUSION: MR imaging shows promise for in vivo measurement of EF and glomerular filtration rate, which may be useful in assessing the clinical importance of renal arterial stenosis.

Late endoleak after endovascular repair of an abdominal aortic aneurysm with multiple proximal extender cuffs.

Late onset graft or attachment site-related endoleaks may be hazardous, and early identification of patients at risk is important. We describe a patient who underwent implantation of a bifurcated stent graft 5.5 cm below the renal arteries because of a technical error with three extender cuffs implanted proximally to bridge the gap. During the 1st year, aneurysm diameter decreased from 68 to 52 mm. After 1 year, the patient had an acute endoleak develop, which originated between two of the extender cuffs and which was accompanied by severe abdominal pain and reexpansion of the aneurysm. This endoleak was treated with insertion of an additional bifurcated stent graft within the extender cuff segment. The patient has been subsequently followed for 6 months and has had no endoleak or symptoms, and aortic diameter has decreased once again to 55 mm.

Endovascular repair reduces early and late morbidity compared to open surgery for abdominal aortic aneurysm.

PURPOSE: To compare systemic complications between standard surgery and endovascular repair of abdominal aortic aneurysms (AAA) for both primary and late secondary procedures. METHODS: At a single center between July 1993 and May 2000, 297 patients (255 men; mean age 73.4 +/- 8.1 years, range 50-93) were treated with open surgical repair; beginning in 1996, 200 (166 men; mean age 73.6 +/- 8.0 years, range 45-96) patients were treated with the AneuRx stent-graft. In a comparison of the cohorts, which were similar in terms of age, gender, and aneurysm diameter, the main outcomes were early major systemic morbidity following the primary procedure to treat the aneurysm and late (>30 days) organ system morbidity for any secondary procedures. RESULTS: Mean length of follow-up for open patients was 20.1 +/- 17.1 months (range 1-150) compared to 12.4 +/- 9.6 months (range 1-60) after endovascular repair (p<0.05). There were 36 (12.1%) systemic complications after the primary open surgery and 15 (7.5%) after endovascular repair (p=NS). There were 43 (14.5%) combined primary and secondary morbidities in the open surgery group versus 15 (7.5%) for patients undergoing endovascular repair (p<0.01). The need for invasive procedures to treat these primary and secondary systemic complications was 4 times greater in the open group (17, 5.7%) than in endograft patients (3, 1.5%) (p<0.05). After secondary procedures (32 in the open group and 30 in the endovascular patients) for graft-related complications, there were 7 (21.9%) adverse events in the open group versus none (0%) for endograft patients (p<0.01). Hospital lengths of stay following both primary and secondary procedures were lower for the endograft patients (p<0.01 and p<0.001, respectively). CONCLUSIONS: Endovascular stent-graft repair compared to open surgery has reduced the early and late morbidity by half. Complications that require invasive or secondary surgical procedures and hospitalization are reduced with endovascular repair.