Long-term Renal Function Following Endovascular Aneurysm Repair With Infrarenal and Suprarenal Aortic Stent-Grafts

Predictors of creatinine rise post-endovascular abdominal aortic aneurysm repair

BACKGROUND

Endovascular abdominal aortic aneurysm repair involves manipulation of the aorta around the renal arteries. Fenestrated grafts involve the direct cannulation, stenting and injecting of contrast into the renal arteries. These procedures may be associated with an acute post-operative creatinine rise.

METHODS

We retrospectively examined data from all endovascular aortic repairs at our institution from 2005 to 2009, where contrast dosage had been recorded. Renal impairment was defined as a 25% increase in creatinine during the 5-day postoperative period. Univariable analysis was undertaken for a number of likely predictors, including: age, contrast dosage, preoperative creatinine, graft type (fenestrated or standard), diabetes mellitus, hypertension, hypercholesterolaemia, ischaemic heart disease, aspirin therapy, statins therapy, non-steroidal anti-inflammatory drug use, preoperative N-acetyl-cysteine and intravenous pre-hydration. Multivariable analysis was then applied to variables with a univariable P-value of < 0.05.

RESULTS

We identified 106 consecutive cases, with complete data for 102. Twenty per cent of patients developed renal impairment (22/102). Contrast dose (P = 0.043) and fenestrated grafts (P = 0.006) were identified as significant risk factors for post-operative creatinine increase (P = 0.043). Multivariable analysis demonstrated that fenestrated grafts were a risk factor independent of contrast dosage (P < 0.05).

CONCLUSIONS

Patients who received a fenestration graft (P < 0.01) and increased contrast dose (P < 0.05) were at a significant increased risk of a 25% post-operative creatinine rise. The risk of fenestration grafts persisted when multivariable regression was performed to control for contrast dosage (P < 0.05). Other variables investigated were not found to be significant in this study.

Endovascular treatment of elective abdominal aortic aneurysms: independent predictors of early and late mortality

BACKGROUND

The purpose of this study was to review our personal experience with patients who underwent elective endovascular repair of abdominal aortic aneurysms so as to detect the predictors of early and late mortality.

METHODS

Between November 2000 and June 2008, a total of 235 consecutive patients (218 men; mean age: 71.9 ± 8.0 years, range: 48-95 years) underwent endovascular repair of abdominal aortic aneurysms. Comorbidities were defined by using the Society for Vascular score grading system and the preoperative risk grade on the basis of the classification of the American Society of Anesthesiologists (ASA). Physical examination and spiral computed tomography were planned at 1, 4, and 12 months after the procedure, and on a yearly basis thereafter. Contrast-enhanced ultrasonography and plain X-rays were also performed.

RESULTS

Primary technical success rate was 97% (228 of 235 cases). The overall hospital mortality was 2.1% (n = 5), ranging from 1.2% and 2.8% for patients with an ASA of score 2 and 3, respectively, to 7.7% for patients with an ASA score of 4. Multivariable analysis confirmed chronic renal failure (OR: 12.12, 95% CI: 1.83-80.17, p = 0.010) and transrenal endograft (OR: 9.61, 95% CI: 1.01-91.57, p = 0.049) as the only independent predictors of early mortality. Follow-up was completed for all 230 patients who were discharged, with a mean follow-up period of 26.3 ± 22.7 months (maximum: 92 months). Kaplan-Meier analysis revealed a reduced survival rate for older patients (p < 0.001) and patients with a larger aneurysm (p < 0.001). A reduced survival rate was also demonstrated for women and patients with higher ASA scores (p = 0.007, and p = 0.003, respectively). In multivariate Cox analysis, ASA score, age, diameter of the aneurysm, and being female independently affected long-term survival.

CONCLUSION

On the basis of our experience, it was concluded that chronic renal failure and the endograft configuration were independent predictors of early mortality. Also, older patients, women, and patients with larger aneurysms and higher ASA scores had the poorest late survival rates.

Long-term risk of mortality and other adverse outcomes after acute kidney injury: a systematic review and meta-analysis

BACKGROUND

Acute kidney injury (AKI) is common in hospitalized patients. The impact of AKI on long-term outcomes is controversial.

STUDY DESIGN

Systematic review and meta-analysis.

SETTING & PARTICIPANTS

Persons with AKI.

SELECTION CRITERIA FOR STUDIES

MEDLINE and EMBASE databases were searched from 1985 through October 2007. Original studies describing outcomes of AKI for patients who survived hospital discharge were included. Studies were excluded from review when participants were followed up for less than 6 months.

PREDICTOR

AKI, defined as acute changes in serum creatinine level or acute need for renal replacement therapy.

OUTCOMES

Chronic kidney disease (CKD), cardiovascular disease, and mortality.

RESULTS

48 studies that contained a total of 47,017 participants were reviewed; 15 studies reported long-term data for patients without AKI. The incidence rate of mortality was 8.9 deaths/100 person-years in survivors of AKI and 4.3 deaths/100 patient-years in survivors without AKI (rate ratio [RR], 2.59; 95% confidence interval, 1.97 to 3.42). AKI was associated independently with mortality risk in 6 of 6 studies that performed multivariate adjustment (adjusted RR, 1.6 to 3.9) and with myocardial infarction in 2 of 2 studies (RR, 2.05; 95% confidence interval, 1.61 to 2.61). The incidence rate of CKD after an episode of AKI was 7.8 events/100 patient-years, and the rate of end-stage renal disease was 4.9 events/100 patient-years.

LIMITATIONS

The relative risk for CKD and end-stage renal disease after AKI was unattainable because of lack of follow-up of appropriate controls without AKI.

CONCLUSIONS

The development of AKI, defined as acute changes in serum creatinine level, characterizes hospitalized patients at increased risk of long-term adverse outcomes.

Comparative analysis of renal function after treatment of infrarenal abdominal aortic aneurysms with a suprarenal fixation device as opposed to open surgery

We analyzed the repercussions on renal function between suprarenal endograft fixation and open surgery in the treatment of infrarenal abdominal aortic aneurysms (IAAAs) and determined the influential factors. Between 1999 and 2005, 59 IAAAs were treated with elective OS and 56 with SEF. The serum creatinine (Cr) level and its clearance were determined before the procedure, in the intensive care unit (ICU), on discharge, and after 1, 6, 12, and 24 months. A deterioration in renal function was considered to be a >30% increase in Cr or a Cr >2 mg/dL. A univariate statistical analysis and a logistical regression analysis were carried out to determine the predictive factors for repercussions on renal function. There were no statistically significant differences in the rate of renal exacerbation between the groups either on discharge (p = 0.52) or after 1 month (p = 0.483), 6 months (p = 0.451), 12 months (p = 0.457), and 24 months (p = 0.682). The only significant difference was that detected in the ICU (p = 0.033). Diabetes mellitus, time spent in the ICU, postoperative intubation time, intraoperative transfusion, and transfusion in the ICU were factors that influenced the deterioration of renal function in the univariate analysis. The only significant factor in the multivariate analysis was the need for transfusion in the ICU. Exacerbation of renal function occurred in both groups independently of treatment type. In the immediate postoperative period, hemodynamic deterioration is more frequent in the open surgery group. Renal exacerbation tended to disappear in both groups during follow-up.

Endovascular Aneurysm Repair Alters Renal Artery Movement: A Preliminary Evaluation Using Dynamic CTA

PURPOSE

To observe the natural renal artery motion during cardiac cycles in patients with abdominal aortic aneurysm (AAA) and how the implantation of stent-grafts may distort this movement.

METHODS

Data on 29 renal arteries from 15 male patients (mean age 72.6 years, range 66-83) treated with Talent or Excluder stent-grafts were acquired using an electrocardiographically (ECG)-gated dynamic 64-slice CT scanner. ECG-triggered retrospective reconstructions were made at 8 equidistant time points over the R-R cardiac cycle. The gated datasets were reconstructed perpendicular to the center flow lumen of each renal artery at 1.2 and 2.4 cm from the renal ostium. Center of mass displacement was determined per cardiac cycle for pre- and post-EVAR renal arteries and compared.

RESULTS

Normal renal artery motion in AAA patients was impressive, with up to 3-mm movement both near and distant from the aorta (mean 2.0+/-0.6 mm, range 1.1-3.0). EVAR inhibited proximal renal motion, resulting in a 31% decrease in maximal movement (mean 1.4+/-0.7 mm, range 0.7-2.0; p < or = 0.05). Distal renal artery motion was unaffected by EVAR, with motion similar to the pre-EVAR state.

CONCLUSION

ECG-gated dynamic CTA is feasible on a 64-slice scanner with a standard radiation dose and can detect potentially serious consequences of EVAR. EVAR alters renal artery motion by limiting proximal motion while leaving distal motion unaffected.

Transrenal Fixation of Aortic Stent-Grafts: Short- to Midterm Effects on Renal Function—A Systematic Review

PURPOSE

To perform a systematic review of the short- to midterm effects of transrenal fixation of aortic stent-grafts on renal function in patients with abdominal aortic aneurysms.

MATERIALS AND METHODS

A search of the PubMed, MEDLINE, and EMBASE databases for English-language literature was performed. Studies with at least 10 patients were included for data analysis. Only studies on transrenal fixation of aortic stent-grafts that included follow-up results for renal function were included. A log-linear model was used for meta-analysis to compare transrenal fixation with infrarenal fixation.

RESULTS

Twenty-two studies met the inclusion criteria. Because two studies analyzed the same group of patients, one was excluded, for a total of 21 studies. Comparisons between transrenal fixation and infrarenal fixation were found in seven studies. For transrenal versus infrarenal fixation, the combined odds ratio, 95% confidence interval, and P value were found to be statistically significant with respect to postprocedural renal infarction only (combined odds ratio, 5.189; 95% confidence interval: 3.198, 8.420; P < .001). No significant difference was found between transrenal and infrarenal fixation with respect to renal dysfunction, renal artery occlusion, or endoleaks (P > .05).

CONCLUSION

Transrenal fixation of aortic stent-grafts seems to be a relatively safe alternative compared with infrarenal fixation in terms of short- to midterm follow-up. Postprocedural renal infarction, however, was significantly higher for transrenal fixation.

Three-dimensional visualization of suprarenal aortic stent-grafts: evaluation of migration in midterm follow-up

PURPOSE

To investigate the midterm results of transrenal fixation of abdominal aortic stent-grafts with regard to device migration and encroachment of stent wires on the renal and visceral branches.

METHODS

Imaging data from 18 patients (15 men; mean age 75 years, range 63-84) undergoing transrenal stent-graft fixation for abdominal aortic aneurysm (AAA) were included in the study. Computed tomographic angiographic data acquired within 1 week of stent-graft implantation were compared to the latest follow-up images. Postprocessing methods generated 3-dimensional (3D) maximum intensity projections (MIP) and virtual intravascular endoscopy (VIE) for evaluation of the relationship between suprarenal stents and aortic branches. Aortic neck angulation was measured in each patient for correlation with the incidence of stent migration.

RESULTS

The mean follow-up period was 40 months. 3D image visualizations showed that the stent-graft moved caudally in all patients (range 2.6-14.2 mm), with migration (>10 mm) observed in 4 (22%) patients. Corresponding VIE images documented changes in stent wire encroachment on the aortic branch ostia in 11 patients, including the number and position of crossing stent wires. There was no close relationship between aortic neck angulation and stent migration.

CONCLUSION

The current study demonstrated that migration occurs at midterm follow-up in transrenally deployed stent-grafts. 3D images were valuable for the assessment of stent migration, as well as its relationship with aortic branch ostia. Long-term follow-up of transrenal fixation deserves to be investigated, especially after observing stent migration relative to aortic ostial encroachment.

Suprarenal stents and other advances in endovascular aneurysm repair

The history of endovascular aneurysm repair has already passed through its phases of "endoexuberance" and "endoscepticism" and there is now a balanced and broad understanding of the technology,its limits and advantages. Current endovascular technique and stent-graft design is the refinement of the accumulated endovascular experience til now. It is important to make note of these technological features incorporated in current stent-grafts and the clinical experience that precipitated their introduction as the technology progresses and new applications are proposed.