Infrarenal Group Research Articles

Effects of Suprarenal Aortic Cross-Clamping and Adjunctive Renal Reconstruction on Outcomes of Open Abdominal Aortic Aneurysm Repair.

Purpose: To analyze our contemporary experience in open abdominal aortic aneurysm (AAA) repair. We focused on the effects of suprarenal (SR) aortic cross-clamping and adjunctive renal reconstruction (RR) on postoperative outcomes.Methods: We retrospectively reviewed our institutional data of 141 consecutive patients who received elective open AAA repair between January 2014 and December 2020.Results: Seventy-five procedures were performed with SR aortic cross-clamping, 20 of which required an adjunctive RR. Patients in the SR group had a higher incidence of postoperative acute kidney injury (AKI) (18.7% vs. 7.6%, P = 0.045). There were no significant between-group differences in other major complications. The 30-day mortality rate in the infrarenal (IR) and SR groups was 0% and 1.3%, respectively. After a median follow-up of 33 months, the rates of chronic renal decline in the IR (18.2%) and SR (21.3%) groups were similar. All reconstructed renal arteries were patent without reintervention. The 5-year overall survival rate in the IR and SR groups was 88.8% and 83.2%, respectively.Conclusions: SR aortic cross-clamping was associated with postoperative AKI but neither SR aortic cross-clamping nor RR affected the long-term renal function or mortality. Open repair remains an essential option for patients with AAA, especially those with complex anatomy.

Time-to-Event Analysis of the Impact of Endovascular Aortic Aneurysm Repair on Chronic Renal Decline

Although randomized studies have revealed the long-term outcomes of the endovascular repair (ER) of abdominal aortic aneurysm (AAA) compared to open repair (OR), there is controversy surrounding chronic renal decline (CRD) after ER. This study reviewed our propensity-matched cohorts of ER and OR to compare CRD rates using a time-to-event analysis. The ER groups undergoing suprarenal (SR) or infrarenal (IR) proximal fixation were also compared with the OR group. This retrospective review of infrarenal AAA repair was conducted from June 2007-December 2017. Patients with ≥1 year of follow-up were included. Cases of supra/pararenal AAAs, infectious AAAs, rupture, or severe chronic kidney disease (CKD) (estimated glomerular filtration rate (eGFR) <15 mL/min/1.73 m2 or dependence on renal replacement therapy) were excluded. CRD was defined as eGFR decline of >20% or de novo hemodialysis during follow-up. Patients treated with ER (ER group) and OR (OR group) were propensity-score matched for age, sex, comorbidities, ejection fraction, respiratory function, and baseline eGFR. Kaplan-Meier analysis compared the freedom from CRD rates of the matched cohorts (mER and mOR groups). Patients treated with SR and IR fixation devices (SR and IR groups) were also separately matched to the OR group, followed by analysis. In total, 1087 patients underwent elective AAA repair. Among them, 944 (512 ER and 432 OR) were enrolled. The ER group was older than the OR group (median age 79 vs 71; P<0.001). The ER group had significantly lower baseline eGFR and more comorbidities than the OR group. Among 187 propensity-score matched pairs (187 mER and 187 mOS patients), background characteristics, including age and baseline eGFR, were comparable, but median renal function follow-up was significantly longer in the mER group than in the mOR group (48 vs 26 months; P<0.001). CRD was observed in 57 patients in the mER group and 30 patients in the mOR group. Kaplan-Meier analysis of the freedom from CRD showed no significant difference between the matched groups (P=0.268); however, in the later follow-up of >4 years, CRD was more common in the mER group. The matched analyses between the OR group and specific fixation groups, comprising 102 OR-SR and 73 OR-IR pairs, demonstrated no significant differences in CRD. Compared to OR, there was no significant impact of ER on CRD at up to 4 years, supporting the safety of ER in terms of the mid-term renal outcome of our present clinical practice.

The Impact of Suprarenal Cross-Clamping on Kidney Function in Patients Undergoing Retroperitoneal Abdominal Aortic Aneurysm Repair following an Enhanced Recovery Protocol

The retroperitoneal approach (RP) is a well-established procedure for juxtarenal and infrarenal (IR) abdominal aortic aneurysm (AAA) repair when an endovascular option is not available. The aim of this study is to compare the effect of suprarenal (SR) and IR aortic clamping on postoperative renal function following an Enhanced Recovery Protocol (ERP). Since there are no defined guidelines within aortic surgery, we focused our attention on the role of fluid and vasopressor administration in the development of postoperative acute kidney injury (AKI). This is a single-center retrospective cohort study on 140 RP aortic aneurysm repair patients operated between 2009 and 2019. Patients were divided in 2 groups: 24 had SR clamping and 116 IR clamping. Since 2009, at our institution all patients have followed an Enchanced Recovery Program which has been implemented as standard care for patients undergoing open AAA repair. The 2 groups were well matched for baseline characteristics, preoperative renal function, and comorbidity. There was an increased need for intraoperative fluids (P=0.015), and vasopressors (P=0.002) in the SR group compared to the IR group. Patients in the SR group showed a higher trend of postoperative AKI as opposed to the control group (37.5% vs. 19.8%), although this event was not statistically significant (P=0.106). Acute Kidney Injury Network stage III requiring temporary dialysis occurred in only 3 patients who all belonged to the IR group. Conversely, stage I and II with a 2- or 3-fold increase in postoperative creatinine were more frequent in the SR group. However, these normalized before discharge in all cases. To the best of our knowledge, none of the above required permanent dialysis. The results from this study show that SR clamping during RP juxtarenal aortic aneurysm repair does not have an adverse effect on postoperative renal function in the short term. However, patients undergoing SR clamping require greater fluid and vasopressor usage, in contrast with the restrictive fluid therapy established by traditional protocols. This could be an important benchmark for future implementation of ERPs in vascular surgery, especially in open procedures requiring visceral clamping.

Comparison of Supraceliac and Infrarenal Aortic Conduits in Liver Transplantation: Is There a Difference in Patency and Postoperative Renal Dysfunction?

Background.Aorto-hepatic conduits can provide arterial inflow for liver transplants in cases where the native hepatic artery is unsuitable for use.Methods.Clinical outcomes of all patients undergoing liver transplantation (LT) with an aorto-hepatic conduit between 2000 and 2016 were included. Recipients were divided into 2 groups: those with a supraceliac (SC) aortic conduit (N = 22) and those with an infrarenal (IR) aortic conduit (N = 82).Results.There was no difference in calculated model for end-stage liver disease score between the 2 groups. The SC group received grafts with a higher mean donor risk index (1.69 versus 1.48; P = 0.02). Early allograft dysfunction was 18.2% in the SC group and 29.3% in the IR group (P = 0.30). In the SC group, 10.5% of patients required initiation of postoperative continuous renal replacement therapy compared to 12.1% of patients in the IR group (P = 0.69). No difference in the rate of postoperative acute kidney injury was seen between the 2 groups (P = 0.54). No significant difference in median creatinine at 1 year was seen between the SC (1.2 mg/dL; IQR 1–1.3) and IR (1.2 mg/dL; IQR 0.9–1.5) groups (P = 0.85). At a median follow-up of 5.3 years, thrombosis of the aortic conduit occurred in 0% of patients in the SC group and 6.1% of patients in the IR group (P = 0.24). Graft survival was not significantly different between the 2 groups (P = 0.47).Conclusions.No difference in renal dysfunction as demonstrated by need for post-LT continuous renal replacement therapy, acute kidney injury, or creatinine at 1 year post-LT was seen between SC and IR aortic conduits. A slight trend of higher conduit thrombosis rate was seen with IR compared to SC aortic conduits; however, this did not reach statistical significance. Both SC and IR aortic conduits represent reasonable options when the native hepatic artery is unsuitable for use.

Suprarenal fixation is associated with worse midterm renal function after endovascular abdominal aortic aneurysm repair compared with infrarenal fixation

BackgroundSeveral reports have indicated that suprarenal (SR) fixation may impair renal function after endovascular abdominal aortic aneurysm repair (EVAR). However, most were short-term or at most, 1-year observational studies; therefore, the midterm effects on renal function remain unclear. This study aimed to identify predictors of midterm renal dysfunction after EVAR and compare renal outcomes in patients after EVAR with SR and infrarenal (IR) fixation. MethodsA total of 467 patients who underwent EVAR of nonruptured IR abdominal aortic aneurysm between 2007 and 2014 were reviewed in a prospectively collected database. Patients on hemodialysis at baseline were excluded. Among the remaining patients, those with 3-year laboratory testing were included in this study. Patients who developed acute kidney injury were excluded from the late renal function estimation. Predictors of 3-year renal function decline were estimated using logistic regression analysis. In addition, patients undergoing EVAR with IR (IR group) and SR fixation devices (SR group) were propensity matched by age, sex, baseline renal function, baseline aneurysm diameter, comorbidities, smoking habits, and regular use of medicines that may act on kidney function. Changes in renal function after surgery were compared between the IR group and the SR group. ResultsDuring the study period, 237 patients (102 IRs and 135 SRs) were followed up with laboratory testing 3 years after surgery. Logistic regression analysis revealed that the use of a SR fixation device was independently predictive of a more than 20% decrease in the estimated glomerular filtration rate at 3 years after EVAR (odds ratio, 2.06; 95% confidence interval, 1.18-3.58; P = .011). Eleven patients who developed acute kidney injury (1 IR and 10 SRs) were excluded from the subsequent analysis. After propensity score matching, 87 pairs were selected (mean age, 77.2 ± 6.3 years; 151 males [86.8%]). The mean follow-up duration was 5.5 ± 1.8 years. In the SR group, estimated glomerular filtration rate at 3 years after surgery decreased significantly more than that in the IR group (mean of 17.8% vs 11.6%, respectively; P = .034). ConclusionsThis study suggests that, compared with EVAR with IR endograft fixation, EVAR with SR endograft fixation is associated with worse outcomes for midterm renal function.

Extraperitoneal Para-Aortic Lymphadenectomy by Robot-Assisted Laparoscopy

Study ObjectiveTo evaluate the outcomes of extraperitoneal para-aortic lymphadenectomy by robot-assisted laparoscopy. DesignA retrospective study (Canadian Task Force classification III). SettingAn academic institution. PatientsTwenty-three consecutive patients with gynecologic cancer who presented for para-aortic lymphadenectomy between March 2016 and May 2017 were reviewed retrospectively. InterventionsExtraperitoneal para-aortic lymphadenectomy by robot-assisted laparoscopy was performed. Measurements and Main ResultsOf the 23 patients reviewed retrospectively, 10 had cervical cancer, 7 had endometrial cancer, 5 had adnexal cancer, and 1 had vaginal cancer. Data regarding patient characteristics, indication for para-aortic lymphadenectomy, type of surgery (infrarenal or inframesenteric), operative time, surgical complications, number of nodes retrieved, and postoperative hospital length of stay were collected. Two patients were excluded because of early perforation of the peritoneum. In total, 21 para-aortic lymphadenectomies were performed (16 infrarenal and 5 inframesenteric). The median skin-to-skin operating time of infrarenal extraperitoneal para-aortic lymphadenectomy by robot-assisted laparoscopy was 170 minutes (range, 90–225 minutes), the median lymph node count was 18 (range, 11–38), and the median estimated blood loss was 50 mL (range, 10–600 mL). The median skin-to-skin operating time of inframesenteric extraperitoneal para-aortic lymphadenectomy by robot-assisted laparoscopy was 120 minutes (range, 90–220 minutes), the median lymph node count was 10 (range, 7–19), and the median estimated blood loss was 30 mL (range, 10–100). Intraoperative complications included 1 thermal lesion of the left genitofemoral nerve, 1 thermal lesion of the left mesoureter (a ureteral stent was placed to avoid ureteric necrosis and fistula without after effect), and 1 lesion of the inferior vena cava that was sutured by robot-assisted laparoscopy. There were 2 additional cases of perforation of the peritoneum that occurred in the infrarenal group. The median hospital length of stay was 1 day (range, 0–7 days). Three patients were readmitted for symptomatic lymphocysts. ConclusionExtraperitoneal para-aortic lymphadenectomy by robot-assisted laparoscopy provides good visualization of the operative field without arm conflict. Still, perforation of the peritoneum and symptomatic lymphocysts are a postoperative concern.

Is Suprarenal Fixation of Aortic Stent Grafts Really without Consequence on the Renal Function?

The renal safety of suprarenal (SR) fixation stent grafts has not been demonstrated yet. The principal objective of this study was to analyze the effect of the type of fixation of stent grafts on the renal function at 1 year, by calculating the estimated glomerular filtration rate (eGFR). The secondary objective was the evaluation of the morphological repercussion of the implants at the renal level by computed tomography. This is a monocentric retrospective study, including all the patients treated electively between 2008 and 2014 with a bifurcated aortic stent graft. We compared the characteristics of the SR and infrarenal (IR) populations and the evolution of the preoperative and 1-year postoperative renal function. Renal function was evaluated by eGFR, according to the Chronic Kidney Disease Epidemiology Collaboration formula, and expressed as mL/min/1.73m2. Regarding morphological evolution, we sought renal infarctions and thromboses or stenoses of the renal arteries (RAS). During the study period, 102 patients were treated: 42 IR and 60 SR. The populations were comparable in terms of operative risk factors and impaired renal function. Preoperative eGFR was similar (SR 71.7±17.8 vs. IR 70.3±17.5, P=0.7). There was no variation in eGFR at 1 year in the IR group (-0.9; P=0.4), whereas a significant decrease was observed in the SR group (-5.6, P<0.0001), a difference which proved to be significant in the intergroup comparison (P=0.0065). This difference persisted after the exclusion of the patients in which at least one polar renal artery had been covered (P=0.019). The proportion of patients with a degradation ≥20% of the eGFR was significantly higher in the SR group (SR 13.3%, n=8 vs. IR 2.4%, n=1; P=0.046). We observed significantly more new or progressing RAS in the SR group (SR 21.67%, n=13 vs. IR 2.38%, n=1; P=0.0035). Overall, 15 infarctions were detected but 9 were due to the cover of a polar artery including 8 in the SR group SR, which were thus excluded (SR 6.7%, n=4 vs. IR 4.8%, n=2; P=0.52). No renal artery thrombosis was diagnosed. The report of a significant difference in the evolution of the renal function and the progression of renal stenoses makes us wonder about the real harmlessness of SR fixation stent grafts. If further reflection is necessary, their systematic use should be called into question, in particular in the presence of an anatomy authorizing the use of IR fixation stent grafts.

Endovascular treatment of isolated abdominal aortic dissection and postoperative aortic remodeling

We report our experience of endovascular management and postoperative aortic remodeling of all types of isolated abdominal aortic dissection (IAAD). This was retrospective study of 28 IAAD patients treated by endovascular means in our department between January 2007 and July 2013. We reviewed the risk factors, clinical features, computed tomography images, follow-up results, and aortic remodeling of these IAAD patients and propose a new morphologic classification into three types-supraceliac, paravisceral, and infrarenal-according to the location of the primary entry site. There were four supraceliac IAADs, one paravisceral IAAD, and 23 infrarenal IAADs in our case series. Suprarenal (supraceliac + paravisceral) IAAD patients were relatively younger than infrarenal patients (45.2 ± 8.6 years vs 60.6 ± 15.5 years; P < .05). No difference was observed between suprarenal and infrarenal IAADs with respect to true lumen, false lumen, and dissection length on imaging (P > .05). All patients received endovascular treatment. The primary technical success rate was 100%. During a follow-up of 35.7 ± 19.9 months, only one infrarenal patient needed an endovascular reintervention. All patients with supraceliac or infrarenal IAADs were alive at the time of follow-up; however, a paravisceral patient died of a dissecting abdominal aortic aneurysm rupture 21 months after endovascular treatment. In the suprarenal and infrarenal groups, endovascular treatment was associated with a significant decrease in the false lumen size and increase in the true lumen size (P < .05). The maximum abdominal aorta diameter decreased after endovascular treatment in both groups but was statistically significant only in the infrarenal group (P < .05). IAAD is a rare vascular disease. We propose it should be categorized as supraceliac, paravisceral, and infrarenal IAAD according to the location of the primary entry site. Endovascular treatment for supraceliac and infrarenal IAADs is a safe method with a high technical success rate and promising aortic remodeling, whereas endovascular treatment for paravisceral IAADs remains difficult.

Analysis of Effects of Fixation Type on Renal Function After Endovascular Aneurysm Repair

To report a prospective nonrandomized study comparing the effects of suprarenal (SR) vs. infrarenal (IR) stent-graft fixation on renal function in patients undergoing endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA). Patients with AAA undergoing elective EVAR between June 2008 and June 2010 were eligible for the comparative study of fixation method on renal function. Patients with impaired renal function [estimated creatinine clearance (eCrCl) <30 mL/min] or a history of renal impairment were not eligible. Renal function was assessed by measuring serum creatinine (SCr) and total proteins and microalbumin in the urine preoperatively, on postoperative day 1, and at 1, 6, and 12 months. The eCrCl was calculated using the Cockcroft-Gault formula. A standard preoperative hydration protocol was followed in all patients, and stent-graft choice was at the operator's discretion. Of 116 patients undergoing elective EVAR in the study period, 16 were ineligible, leaving 100 patients (95 men; median age 74 years) enrolled in the study (49 SR and 51 IR). There was no statistically significant difference between the groups in the prevalence of any risk factor, the baseline SCr and eCrCl values, contrast usage, or procedure duration. At the postoperative measurement, there was no significant deterioration of renal function in either group, although total urinary proteins increased significantly in both groups (IR p=0.01, SR p<0.001). At the 12-month follow-up, patients in the IR group had no significant alteration in any marker vs. baseline, while patients in the SR group had significant alterations in SCr (p=0.001), eCrCl (p<0.001), and microalbumin (p=0.04) in urine. The number of patients with a >20% decrease in eCrCl was not significantly different between the groups. No patient had an adverse renal event. Deterioration in renal function was observed 12 months after EVAR in patients receiving a stent-graft with suprarenal fixation, even though this did not seem to increase the likelihood of postoperative renal impairment. Furthermore, suprarenal fixation may be responsible for progressively significant proteinuria. Further studies are needed to determine the long-term impact of suprarenal fixation on renal function and investigate the potential risk of progressive renal disease in relation to type of fixation.

Suprarenal graft fixation in endovascular abdominal aortic aneurysm repair is associated with a decrease in renal function

Suprarenal endograft fixation is routinely used in the endovascular repair of abdominal aortic aneurysms (EVAR) to enhance proximal endograft attachment but can be associated with an adverse outcome in renal function. This prospective study assessed the effect of suprarenal fixation on serum creatinine concentration and estimated glomerular filtration rate (eGFR), calculated by the Modified Diet in Renal Disease equation, 12 months after elective EVAR. Patients undergoing elective EVAR were divided into suprarenal vs infrarenal fixation groups matched for age, sex, smoking, and aneurysm diameter. Serum creatinine and eGFR were measured at baseline, 6, and 12 months. Included were 92 patients (two women) with a mean age of 71 ± 7 years, with 46 in each group. No device-related complications were noted. Serum creatinine did not differ significantly between groups at 6 (P = .24) or 12 (P = .08) months but significantly increased in the suprarenal group at 12 months (1.08 ± 0.36 to 1.16 ± 0.36 mg/dL; P < .001) vs baseline. The eGFR (mL/min/1.73 m(2)) did not differ significantly at baseline between the suprarenal (85 ± 27) and infrarenal (80 ± 28; P = .33) groups or at 6 months (88 ± 29 vs 77 ± 24, respectively; P = .07). At 12 months, the suprarenal group had a lower eGFR (73 ± 23) than the infrarenal group (84 ± 26; P = .027). The eGFR at 12 months showed a significant decrease in the suprarenal (80 ± 28 to 73 ± 23; P < .001) but not in the infrarenal group (85 ± 27 to 84 ± 26; P = .48). The drop in eGFR differed significantly at 12 months in the infrarenal vs the suprarenal (0.82 vs -6.94; P < .001) group. No patient progressed to end-stage renal disease or disclosed a drop in eGFR > 30%. In contrast to previous studies, this study suggests that suprarenal endograft fixation in elective EVAR is associated with a drop in eGFR at 12 months.

Effect of suprarenal fixation on renal function in endovascular abdominal aneurysm repair patients

to assess the the mid-term renal function of abdominal aortic aneurysm (AAA) patients following supra-renal endovascular repair. from March 2005 to December 2009, 290 AAA patients were included and grouped depending upon whether they had received infra-renal (IR) or supra-renal (SR) EVAR. SR was performed in 173 patients, with a mean age of (72 ± 8) years and 85.0% for male. IR was performed in 117 patients, with a mean age of (71 ± 9) years and 90.6% for male. Preoperative and 1 week, 1-, 3-, 6-, 12-month postoperative serum creatinine (Cr) and cystatin C (Cys-C) were detected. Estimated glomerular filtration rate (eGFR) were calculated by Cystatin-based formula and Cr-based Cockcroft formula. T test were used to determine statistical difference between or within groups. all Patients received Talent or Zenith endograft. The ratio of device-used were 67/106 in SR group and 25/92 in IR group (P < 0.05). The other characteristics and operative files in two groups were well matched. Preoperative Cr and Cys-C were (82 ± 8) µmol/L and (0.89 ± 0.11) mg/L for SR group, (81 ± 11) µmol/L and (0.87 ± 0.15) mg/L for IR group, no difference between groups. Compared to preoperative renal markers within each group, Cr, Cys-C and eGFR worsening were found at 1 week and 12 months postoperative (P < 0.05). At 1 week postoperative, Cr in SR group and IR group were (98 ± 11) µmol/L and (95 ± 13) µmol/L, Cys-C were (1.01 ± 0.10) mg/L or (0.99 ± 0.10) mg/L. At 12 months postoperative, Cr in SR group and IR group were (91 ± 15) µmol/L or (90 ± 12) µmol/L, Cys-C were (1.03 ± 0.20) or (1.02 ± 0.21) mg/L. Also, Cys-C [SR: (0.93 ± 0.17) mg/L, IR: (0.92 ± 0.31) mg/L] and eGFR by Cys-C worsening were found at 6 months postoperative. There was no difference between groups in patients Cr, Cys-C and eGFR at each follow-up time interval. the use of SR fixation was not significantly associated with mid-term postoperative renal injury.

Suprarenal aortic cross-clamp position: A reappraisal of its effects on outcomes for open abdominal aortic aneurysm repair

With the increasing use of endovascular aneurysm repair, a greater proportion of open aneurysm repairs in the future are expected to be more complex and require suprarenal cross-clamping. We sought to evaluate the effects of suprarenal (SR) vs infrarenal (IR) aortic cross-clamp position in abdominal aortic aneurysm (AAA) repair in an updated single center series. All elective open AAA repairs performed at our institution between 1990 and 2006 were entered into a prospective database and reviewed retrospectively. Our main stratification variable was SR vs IR. The SR group was further subdivided into those requiring an adjunctive renal revascularization procedure (SR+RRP; n = 54) and those who did not (SR-RRP; n = 117). Univariate and multivariate models were used to analyze the effect of baseline variables and operative variables on our primary endpoint 30-day mortality as well as secondary endpoints such as major adverse events, postoperative decline in renal function (defined as doubling of baseline creatinine to level >2 mg/dL, or new-onset dialysis) and long-term survival. A propensity score model was developed to control for confounding variables associated with the use of an SR cross-clamp. A total of 1020 patients underwent elective AAA repair, of which 849 (83.2%) were IR and 171 (16.8%) were SR. Diabetes (14.6% vs 9.1%, P = .027), hypertension (70.2% vs 61.4%, P = .03), and chronic renal failure (14.0% vs 4.7%, P = .001) were more prevalent in the SR group, and mean aneurysm size was larger (6.0 cm vs 5.6 cm, P = .001). Estimated blood loss was higher (1919 mL vs 1257 mL, P = .001) in the SR group, as was mean length of stay (12.6 days vs 10.7 days, P = .047). Perioperative (30-day) mortality rate was 1.8% for the SR group and 1.2% for the IR group (P = .44). Postoperative decline in renal function was 17.0% in SR vs 9.5% in IR (P = .003), however, new-onset dialysis was rare (0.6% SR, 0.8% IR, P = NS). The combination of SR+RRP was associated with an increased risk for postoperative decline in renal function (14.8% SR+RRP, 4.3% SR-RRP, P = .016). Preoperative renal failure was strongly associated with postoperative renal decline (odds ratio [OR] 8.15, 2.92-22.8, P < .0001). Propensity score analysis demonstrated that the use of an SR cross-clamp was associated with an increased risk for postoperative renal decline (OR 2.66, 1.28-5.50, P = .009). Major adverse events were more prevalent in the SR group compared to the IR group (17.0% vs 9.5%, P = .003). Five-year survival was 69.1% + 1.9% for the IR group and 67.7% + 4.3% for the SR group (P = 0.38) by life table analysis. Suprarenal cross-clamping is associated with low mortality and significant but acceptable morbidity, including postoperative decline in renal function. The results from this series may serve as relevant background data when evaluating emerging branched and fenestrated endograft technologies.

Renal Function after Endovascular Aortic Aneurysm Repair: A Single-Center Experience with Transrenal versus Infrarenal Fixation

To describe the short-term consequences of endovascular aortic aneurysm repair (EVAR) on renal function after infrarenal (IR) versus transrenal (TR) stent-graft fixation. Between December 1996 and January 2006, 369 consecutive patients were treated with EVAR. All patients had an AneuRx or a Talent stent-graft implanted using IR (AneuRx) or transrenal (Talent) fixation. Post-EVAR, a standardized follow-up scheme included computed tomography (CT) scanning and serum creatinine measurements at 2 days, 3 months, and 12 months. Postoperative renal dysfunction was defined as a >20% decrease in serum creatinine clearance compared to baseline, the presence of new-onset dialysis, or both. Of the 369 patients, 309 (291 men; mean age 71+/-7 years, range 63-82) had complete 1-year follow-up and were included in this study. An IR stent-graft was placed in 190 patients, and a TR stent-graft was placed in the remaining 119 patients. At discharge, renal dysfunction occurred in 3.7% of the patients in the IR group versus 5.9% in the TR group (p = NS) and rose significantly to 13.7% in the IR group (p = 0.001) and 15.1% in the TR group (p = 0.02) at the 1-year follow-up. However, no significant difference was noted between the IR and TR groups at either time point. At the 1-year follow-up, at least 50% of renal dysfunction was caused by obstructions of (accessory) renal arteries and renal infarctions. During the follow-up interval, 3 (0.97%) of 309 patients underwent new-onset dialysis. Both infrarenal and transrenal fixation techniques in EVAR will lead to a significant rise in renal dysfunction during the first year. A few patients with dysfunction will require dialysis.

Iliac fixation inhibits migration of both suprarenal and infrarenal aortic endografts

To evaluate the role of iliac fixation in preventing migration of suprarenal and infrarenal aortic endografts. Quantitative image analysis was performed in 92 patients with infrarenal aortic aneurysms (76 men and 16 women) treated with suprarenal (n = 36) or infrarenal (n = 56) aortic endografts from 2000 to 2004. The longitudinal centerline distance from the superior mesenteric artery to the top of the stent graft was measured on preoperative, postimplantation, and 1-year three-dimensional computed tomographic scans, with movement more than 5 mm considered to be significant. Aortic diameters were measured perpendicular to the centerline axis. Proximal and distal fixation lengths were defined as the lengths of stent-graft apposition to the aortic neck and the common iliac arteries, respectively. There were no significant differences in age, comorbidities, or preoperative aneurysm size (suprarenal, 6.0 cm; infrarenal, 5.7 cm) between the suprarenal and infrarenal groups. However, the suprarenal group had less favorable aortic necks with a shorter length (13 vs 25 mm; P < .0001), a larger diameter (27 vs 24 mm; P < .0001), and greater angulation (19 degrees vs 11 degrees ; P = .007) compared with the infrarenal group. The proximal aortic fixation length was greater in the suprarenal than in the infrarenal group (22 vs 16 mm; P < .0001), with the top of the device closer to the superior mesenteric artery (8 vs 21 mm; P < .0001) as a result of the 15-mm uncovered suprarenal stent. There was no difference in iliac fixation length between the suprarenal and infrarenal groups (26 vs 25 mm; P = .8). Longitudinal centerline stent graft movement at 1 year was similar in the suprarenal and infrarenal groups (4.3 +/- 4.4 mm vs 4.8 +/- 4.3 mm; P = .6). Patients with longitudinal centerline movement of more than 5 mm at 1 year or clinical evidence of migration at any time during the follow-up period comprised the respective migrator groups. Suprarenal migrators had a shorter iliac fixation length (17 vs 29 mm; P = .006) and a similar aortic fixation length (23 vs 22 mm; P > .999) compared with suprarenal nonmigrators. Infrarenal migrators had a shorter iliac fixation length (18 vs 30 mm; P < .0001) and a similar aortic fixation length (14 vs 17 mm; P = .1) compared with infrarenal nonmigrators. Nonmigrators had closer device proximity to the hypogastric arteries in both the suprarenal (7 vs 17 mm; P = .009) and infrarenal (8 vs 24 mm; P < .0001) groups. No migration occurred in either group in patients with good iliac fixation. Multivariate logistic regression analysis revealed that iliac fixation, as evidenced by iliac fixation length (P = .004) and the device to hypogastric artery distance (P = .002), was a significant independent predictor of migration, whereas suprarenal or infrarenal treatment was not a significant predictor of migration. During a clinical follow-up period of 45 +/- 22 months (range, 12-70 months), there have been no aneurysm ruptures, abdominal aortic aneurysm-related deaths, or surgical conversions in either group. Distal iliac fixation is important in preventing migration of both suprarenal and infrarenal aortic endografts that have longitudinal columnar support. Secure iliac fixation minimizes the risk of migration despite suboptimal proximal aortic neck anatomy. Extension of both iliac limbs to cover the entire common iliac artery to the iliac bifurcation seems to prevent endograft migration.

Endovascular aneurysm repair with suprarenal vs infrarenal fixation: A study of renal effects

Although suprarenal fixation may be of benefit during endovascular aneurysm repair (EVAR), its safety with regards to renal effects remains uncertain. To date, there has been no controlled study of the topic, with most reports relying upon single-center experiences that use heterogeneous patient populations and devices from different manufacturers. The purpose of this analysis was to evaluate the effect of suprarenal fixation on renal function by comparing homogeneous patient populations receiving EVAR grafts from a single manufacturer that are identical in design and delivery method, except for utilizing either suprarenal (SR) or infrarenal (IR) fixation. During two pivotal US Food and Drug Administration trials, 283 patients underwent EVAR with the Powerlink bifurcated graft. The trials' inclusion and exclusion criteria and grafts were identical except for fixation scheme. Clinical, laboratory, and computed tomographic (CT) data were retrospectively reviewed. A comparison of preoperative, perioperative (1 to 7 days), and postoperative (>7 days) alterations in serum creatinine (SCr), creatinine clearance (CrCl), and blood pressure was performed. Renal adverse events were determined by CT scan and clinical chart review and included renal infarction, renal artery stenosis (either progressive or requiring renal stent placement), and renal artery occlusion. Both SR and IR groups demonstrated a significant increase in SCr and a decrease in CrCl over time. No significant difference in SCr or CrCl existed between groups during any time period. There were no differences in postoperative renal impairment (IR, 10.2%; SR, 7.6%, P = .634), the need for hemodialysis (IR, 0.7%; SR, 0%, P = 1.00), or systolic and diastolic blood pressure during subsequent follow-up between treatment groups. There was no significant difference in the number of renal adverse events detected by CT between the IR (10, 6.8%) and SR (3, 3.8%) groups (P = .550). Suprarenal fixation does not lead to a significant increase in acute renal events, renal impairment, or alteration in blood pressure compared with infrarenal fixation. Patients undergoing aneurysm repair with devices that use either suprarenal or infrarenal fixation develop progressive renal dysfunction over time. Further studies are needed to determine the long-term effects of suprarenal fixation on renal function and progression of renal artery stenosis.

Relationship of proximal fixation to postoperative renal dysfunction in patients with normal serum creatinine concentration

Objectives This study was performed to determine whether there is deterioration in renal function during follow-up in patients who have undergone endovascular aneurysm repair (EVAR), as recommended by the device manufacturers; to determine whether suprarenal fixation correlates with impairment of renal function; and to explore the potential implication of life-long surveillance of renal function with contrast-enhanced computed tomography. Methods One hundred forty-six consecutive patients underwent EVAR at our institution. Data from 113 of these patients who were free from preoperative renal insufficiency or postoperative renal disease were analyzed. Fifty-three patients received infrarenal (IR) fixation devices, and 60 patients received suprarenal (SR) fixation devices. All SR fixation devices were placed under investigational device exemption protocols. The average follow-up was 688 days. Sixty-five consecutive patients who had undergone open repair of an abdominal aortic aneurysm (AAA) served as the control group. Results Preoperative creatinine concentration, intraoperative blood loss, contrast volume, and number of contrast-enhanced procedures were not significantly different between the IR and SR groups. Two renal artery occlusions (1 SR, 1 IR; P = NS) were identified, and 8 renal infarcts (5 SR, 3 IR; P = NS). There was an increase in mean creatinine concentration in the open AAA, IR, and SR fixation groups at each time point in the analysis. Mean elevation in creatinine concentration at 12, 24, and 36 months was 0.10, 0.10, and 0.04 mg/dL, respectively, for open AAA repair; 0.20, 0.21, and 0.28 mg/dL for IR fixation; and 0.15, 0.21, and 0.12 mg/dL for SR fixation. At life table analysis, renal impairment at 36 months was seen in 36% ± 9% of patients in the IR group, 25% ± % of patients in the SR group, and 19% ± 6% of patients in the open AAA group ( P = .04 for IR fixation vs open AAA repair). Conclusions A decrease in kidney function is seen after EVAR, regardless of fixation level, that is independent of renal disease and renal arterial occlusion. In patients with normal renal function the site of proximal fixation does not affect postoperative creatinine concentration. The decrease in renal function is likely related to the repetitive administration of contrast agent.

Hemostatic alterations associated with supraceliac aortic cross-clamping

Purpose: The causative role of consumptive coagulopathy in the development of bleeding complications after supraceliac (SC) aortic cross-clamping (AXC) has been challenged by recent reports that ascribe this coagulopathy to primary fibrinolysis. This theory is made on the basis of evidence that tissue plasminogen activator (t-PA) antigen (Ag) levels increase after SC AXC. However, t-PA Ag levels reflect both active and inactive (bound to serum t-PA inhibitors) forms of serum t-PA, and elevations confirm the presence of fibrinolysis only in conjunction with an increase in t-PA activity. Methods: To investigate the etiology of this coagulopathy, we submitted eight pigs to SC AXC and six pigs to infrarenal (IR) AXC for 30 minutes. Blood was drawn from the portal vein, the hepatic vein, and the carotid artery before AXC, just before unclamping, and 5, 30, and 60 minutes after unclamping. Prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen (FBG), platelets (PLT), thrombin-antithrombin complexes (TAT), t-PA Ag, t-PA activity, plasminogen activator inhibitor-1 (PAI-1), and α2-antiplasmin (AP) activities were measured. Statistical analysis was performed by using repeated measures analysis of variance and t tests Results: The PT did not differ between the two groups at any point. After unclamping, in the SC group there was a drop in PLT levels (P =.005), a decrease in FBG levels (P <.001), and a trend toward PTT prolongation (P =.06) compared with baseline. In contrast, there were no changes in PTT, PLT levels, or FBG levels in the IR group. TAT, a serum marker of thrombin generation, increased with SC AXC (P =.04), remained elevated 5 minutes after unclamping (P =.08), and returned to normal 30 minutes after unclamping. In contrast, TAT levels did not change in the IR control group. In the SC AXC group, the TAT levels did not differ between the three test sites at any time. SC AXC was associated with an increase in t-PA Ag just before unclamping (P <.001) and 5 minutes after unclamping (P =.002), but IR AXC was not. t-PA activity levels decreased in both experimental groups 30 and 60 minutes after unclamping. Levels of α2-AP activity decreased to a similar degree in both groups after unclamping when compared with baseline Conclusion: Thirty minutes of SC AXC results in intravascular thrombosis that cannot be localized to the ischemic visceral circulation. This intravascular thrombosis is associated with consumption of clotting factors. Thirty minutes of SC AXC causes an activation of fibrinolytic pathways that does not result in a hyperfibrinolytic state. An increase in t-PA Ag without a rise in t-PA activity does not represent true fibrinolysis, but rather an increase in the bound, inactive forms of serum t-PA. Both IR and SC AXC result in decreased fibrinolytic activity (“fibrinolytic shutdown”) after release of the aortic clamp. (J Vasc Surg 2002;35:100-8.)

Analysis of Coagulation Changes Associated with Supraceliac Aortic Crossclamping Using Thromboelastography

Introduction. The etiology of the coagulation changes seen with supraceliac (SC) aortic crossclamping (AXC) remains controversial; both primary fibrinolysis and clotting factor consumption have been implicated. The cause of these changes was investigated with thromboelastography (TEG), a test that measures the viscoelastic properties of thrombus to dynamically assess coagulation and fibrinolysis.Methods. Eight pigs underwent SC AXC for 30 min; 5 pigs undergoing 30 min of infrarenal (IR) aortic clamping served as controls. Blood was drawn before AXC, before unclamping, and 5 and 60 min after unclamping. Thromboelastography and standard coagulation tests [prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen, and platelet count] were performed. Measured TEG parameters included fibrinolytic index (a measure of fibrinolysis), r value (a reflection of intrinsic coagulation cascade activity), and the α angle and K values (measures of the speed of solid clot formation). Repeated measures ANOVA and t test were used for statistical analysis.Results. There was no difference in the fibrinolytic index at any time point between the two groups. Increased activity of the intrinsic coagulation cascade during SC clamping was reflected by a lower R value just before unclamping (12.6 ± 3.0 vs 20.0 ± 3.0, P = 0.048) compared to IR AXC. Decreased speed of solid clot formation was noted 5 min after unclamping in the SC group but not the IR group [as defined by an increased K value (ANOVA, P = 0.010) and a decreased α angle value (ANOVA, P = 0.005)]. Fibrinogen levels were lower in the SC than in the IR group 5 (P = 0.013) and 60 min after unclamping (P = 0.02), but PT, PTT, and platelets did not differ between the groups at any time points.Conclusions. Thirty minutes of SC AXC does not result in fibrinolysis. There is increased clotting activity during SC clamping followed by decreased speed of clot formation and decreased fibrinogen levels after unclamping. These changes are consistent with clotting factor consumption.

Supraceliac, but not infrarenal, aortic cross-clamping upregulates neutrophil integrin CD11b

To evaluate the effects of supraceliac and infrarenal aortic cross-clamping on the expression of neutrophil integrin in CD11b (a marker of systemic cytokine release). Two groups, determined by anatomic placement of aortic cross-clamp. Laboratory personnel were blinded as to group assignment. University teaching and community hospitals. Laboratory facilities used were university and Veteran's Affairs medical centers. Patients scheduled for aortic surgery. Blood sampling was performed at baseline, after 30 minutes of aortic cross-clamp duration, 30 and 90 minutes after reperfusion (for tumor necrosis factor-alpha plasma levels in infrarenal cross-clamp group), and at baseline and 90 minutes reperfusion (for neutrophil CD11b expression quantification) in both groups. Tumor necrosis factor-alpha measured by ELISA technique did not change at any time period in the infrarenal clamping group. Neutrophil CD11b expression, measured by double antibody staining and FACScan analysis, did not change significantly at 90 minutes of reperfusion in the infrarenal group, but increased significantly (p < 0.05) in the supraceliac aortic cross-clamp group. Neutrophil integrin CD11b has been demonstrated to be the primary adhesive glycoprotein responsible for neutrophil organ entrapment and subsequent neutrophil-mediated reperfusion injury. These results suggest that upregulation of neutrophil integrin CD11b after supraceliac aortic clamping may in part be responsible for the higher incidence of acute lung injury after thoracic aortic aneurysm repair requiring supraceliac clamping when compared with infrarenal aneurysm surgery.

Supraceliac clamping in the surgical treatment of abdominal aortic aneurysm. An experimental study in dogs.

Previous reports have suggested the use of supraceliac aortic clamping in the surgical treatment of abdominal aortic aneurysm of difficult approach. The objective of the present report was to study the hepatic and renal metabolic changes of three groups of dogs submitted to temporary clamping (30 minutes) of the abdominal aorta at three different levels: below the renal arteries, infrarenal group (8 dogs); above the renal arteries, suprarenal group (9 dogs); above the celiac artery, supraceliac group (9 dogs). Blood bilirubin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea nitrogen, and creatinine levels were measured before clamping and 5 minutes and 24 hours after reperfusion of the aorta. Bilirubin levels remained unchanged 5 minutes and 24 hours after reperfusion in all three groups. Alkaline phosphatase levels were significantly increased in all three groups 24 hours after reperfusion. ALT levels increased significantly in the supraceliac group and AST levels increased significantly in the infrarenal and supraceliac groups 24 hours after reperfusion of the aorta. However, despite these significant increases after reperfusion, the levels of these hepatic enzymes were still within the normal range for dogs. Urea nitrogen and creatinine levels showed that renal function did not change in any of the three groups. We conclude that supraceliac, infrarenal or suprarenal aortic clamping for 30 minutes do not promote any important changes in the hepatic or renal function of dogs.