Suprarenal Cross-clamping Research Articles

A study of mortality frequency and clinical course of postoperative renal and abdominal visceral complications following open aortic surgery for abdominal aortic aneurysm requiring supra renal aortic cross-clamp

ABSTRACT Background: Endovascular interventions for abdominal aortic aneurysms (AAAs) are fast evolving; however, due to higher rates of reintervention and no survival benefits after 2 years, open surgical procedures are pivotal. Here, we present mortality and morbidity analysis of open surgical procedures requiring suprarenal cross clamping for AAA repair. Materials and Methods: The present study is a retrospective hospital record-based study selecting 34 cases that required suprarenal cross-clamping out of 200 abdominal aortic aneurysm surgeries. Out of the total 34 patients, 22 (64.7%) were males and 12 (35.3%) were females. The mean age of all participants was 58.05 years (with an 8.1 standard deviation). Out of 34 cases, 20 cases (58.8%) were classified as suprarenal and pararenal aneurysms and 14 cases were juxtarenal aneurysms (41.2%). Out of the 14 juxtrarenal aneurysm cases, 7 (50%) were atherosclerotic and 2 (14.3%) were Marfan’s Syndrome, while inflammatory were 2 (14.3%) and infected were 2 (14.3%) and 1 was a case of Takayasu’s arteritis (7.1%). Mortality and morbidity, including renal function decline, need for hemodialysis, acute pancreatitis, and hepatic and gastrointestinal (GI) complications, were recorded as early (up to 30 days) and late (up to 1 year). The results were recorded separately for suprarenal, pararenal, and juxtarenal aneurysm types and presented in that way, which is the highlight of our study. Results: Early mortality occurred in 3/34 (8.8%) cases, where late mortality happened in 2/34 (5.9%) cases, which are exclusive of early mortality cases. Considering the early mortality and complications, 2 out of 4 cases (50.0%) of the suprarenal group died early, renal dysfunction happened in 4/34 cases (11.8%), of which 3 (8.8%) required dialysis. No cases of pancreatitis, while acute liver failure complicated 3 out of 34 (8.8%) cases. GI bleed and mesentric ischemia each complicated 2 out of 34 cases (5.9%). Prolonged ileus was noticed as the most common GI complication complication. Early mortality was highest in the suprarenal group with renal dysfunction. Considering late mortality and complications, 1 out of 16 cases (6.3%) of the pararenal group died late, and 1 out of 14 cases (7.1%) of the juxta renal cases died late. There was no late mortality in the suprarenal group. Renal dysfunction happened in 2/34 cases (5.9%), of which none required dialysis. Complete data have been presented as per the aneurysm type. Conclusions: Patients requiring suprarenal aortic cross-clamping for open surgical repair of abdominal aorta aneurysm are usually high-risk surgical candidates, considering both early and late mortality and morbidity. Early mortality was maximum in the suprarenal group (50.0%), as were postoperative renal dysfunction and hemodialysis requirements. Visceral complications (acute liver failure and GI complications) were also maximum with the suprarenal group. Late mortality was recorded in the pararenal and juxtarenal groups, with renal dysfunction being recorded in the suprarenal and juxtarenal groups. Visceral complications were recorded in both pararenal and juxtarenal groups. One confounding factor could be the high early mortality in the suprarenal group, resulting in less number of survivors for late postoperative recording. Overall, we conclude that suprarenal aortic aneurysms carry the highest burden of early mortality with renal and visceral complications postoperative.

Contemporary indications for open abdominal aortic aneurysm repair in the endovascular era

ObjectiveDespite the emergence of endovascular aneurysm repair (EVAR) as the most common approach to abdominal aortic aneurysm repair, open aneurysm repair (OAR) remains an important option. This study seeks to define the indications for OAR in the EVAR era and how these indicatioxns effect outcomes. MethodsA retrospective cohort study was performed of all OAR at a single institution from 2004 to 2019. Preoperative computed tomography scans and operative records were assessed to determine the indication for OAR. These reasons were categorized into anatomical contraindications, systemic factors (connective tissue disorders, contraindication to contrast dye), and patient or surgeon preference (patients who were candidates for both EVAR and OAR). Perioperative and long-term outcomes were compared between the groups. ResultsWe included 370 patients in the analysis; 71.6% (265/370) had at least one anatomic contraindication to EVAR and 36% had two or more contraindications. The most common anatomic contraindications were short aortic neck length (51.6%), inadequate distal seal zone (19.2%), and inadequate access vessels (15.7%). The major perioperative complication rate was 18.1% and the 30-day mortality was 3.0%. No single anatomic factor was identified as a predictor of perioperative complications. Sixty-one patients (16.5%) underwent OAR based on patient or surgeon preference; these patients were younger, had lower incidences of coronary artery disease and chronic obstructive pulmonary disease, and were less likely to require suprarenal cross-clamping compared with patients who had anatomic and/or systemic contraindications to EVAR. The patient or surgeon preference group had a lower incidence of perioperative major complications (8.2% vs 20.1%; P = .034), shorter length of stay (6 days vs 8 days; P < .001) and no 30-day mortalities. The multivariable adjusted risk for 15-year mortality was lower for patient or surgeon preference patients (adjusted hazard ratio, 0.44; 95% confidence interval, 0.24-0.80; P = .007) compared with those anatomic or systemic contraindications. ConclusionsWithin a population of patients who did not meet instruction for use criteria for EVAR, no single anatomic contraindication was a marker for worse outcomes with OAR. Patients who were candidates for both aortic repair approaches but elected to undergo OAR owing to patient or surgeon preference have very low 30-day mortality and morbidity, and superior long-term survival rates compared with those patients who underwent OAR owing to anatomic and/or systemic contraindications to EVAR.

Adjuncts to the Management of Graft Aorto-Enteric Erosion and Fistula with in situ Reconstruction

The objective of this retrospective single centre study was to determine whether different enteric reconstruction methods and adjuncts confer a benefit after in situ reconstructions (ISRs) of graft aorto-enteric erosion (AEnE) and fistula (AEnF).Primary endpoints were in hospital mortality and AEnE/F recurrence. Survival was estimated using the Kaplan-Meier method and explanatory factors were searched for using uni- ± multivariable Cox regression analysis. In 2013, a multidisciplinary team meeting was convened and since then the primary operator has always been a senior surgeon.Sixty-six patients were treated for AEnE (n = 38) and AEnF (n = 28, 42%) from 2004 to 2020. All patients with AEnF presented with gastrointestinal bleeding (vs. 0 for AEnE; p < .001). Signs of infection were seen in 50 patients (76% [37 for AEnE vs. 13 for AEnF]; p < .001). Referrals for endograft infection increased over time (n = 15, 23%; one before 2013 vs. 14 after; p = .002). Most patients underwent complete graft excision (n = 52, 79%) with increasing suprarenal cross clamping (n = 21, 32%; four before 2013 vs. 17 after; p = .015). Complex visceral reconstructions decreased over time (n = 31, 47%; 17 before 2013 vs. 14 after; p = .055), while "open abdomens" (OAs) increased (one before 2013 vs. 22 after; p < .001), reducing operating time (p = .012). In hospital mortality reached 42% (n = 28). Estimated survival reached 47.6% (95% confidence interval [CI] 35.0 - 59.1) at one year and 45.6% (95% CI 33.0 - 57.3) at three years and was higher for AEnE than for AEnF (log rank p = .029). AEnE/F recurrence was noted in 12 patients (18%). Older age predicted in hospital mortality in multivariable analysis (p = .034). AEnE/F recurrence decreased with the presence of a primary senior surgeon (vs. junior; p = .003) and OA (1 [4.4%] vs. 11 [26%] for primary fascial closure; p = .045) in univariable analysis.Mortality and recurrence rates remain high after ISR of AEnE/F. Older age predicted in hospital mortality. Primary closure of enteric defects ≤ 2 cm in diameter reduced operating time without increasing the recurrence of AEnF.

Contemporary Indications for Open Abdominal Aortic Aneurysm Repair in the Endovascular Era

Despite the emergence of endovascular abdominal aortic aneurysm repair (EVAR) as the most common approach to repair, open aneurysm repair (OAR) remains a critical option. We sought to define the indications for OAR in the EVAR era and how these indications affect the outcomes. We performed a retrospective review of all OAR cases at a single institution from 2004 to 2020. Preoperative computed tomography scans and operative records were assessed to determine the indications for OAR. These reasons were categorized into anatomic contraindications, systemic factors (ie, connective tissue disorders, contraindication to contrast dye), and patient and/or surgeon preference (candidates for both EVAR and OAR). The perioperative and long-term outcomes were compared. A total 370 patients were included in the analysis. Of the 370 patients, 265 (71.6%) had at least one anatomic contraindication to EVAR (36% had two or more contraindications). The most common anatomic contraindications were a short aortic neck length (51.6%), an inadequate distal seal zone (19.2%), and inadequate access vessels (15.7%). The major perioperative complication rate was 18.1%, and the 30-day mortality was 3.6%. No single anatomic factor was identified as a predictor of perioperative complications. Sixty-one patients (16.5%) had undergone OAR by patient and/or surgeon preference. These patients were younger, had a lower incidence of coronary artery disease and chronic obstructive pulmonary disease, and were less likely to require suprarenal cross-clamping than were the patients who had had anatomic and/or systemic contraindications to EVAR. The patient/surgeon preference group had a lower incidence of perioperative major complications (8.2% vs 20.1%; P = .034), a shorter length of stay (6 vs 8 days; P < .001), and no 30-day mortality. The multivariable adjusted risk for 15-year mortality was lower for the patient/surgeon preference group (19.7% vs 39.5%; adjusted hazard ratio, 0.44; 95% confidence interval, 0.24-0.80; P = .007) than for the anatomic/systemic contraindications group (Table). Within a population of patients who did not meet the instructions for use criteria for EVAR, no single anatomic contraindication was a marker for worse outcomes after OAR. Patients who were candidates for both aortic repair approaches but who had elected to undergo OAR had 30-day mortality of 0% and superior perioperative morbidity and long-term survival rates.TableShort- and long-term outcomes stratified by OAR indicationVariableSurgeon/patient preference (n = 61)Anatomical/systemic contraindication (n = 309)P valueEstimated blood loss, mL1177 ± 9531656 ± 1653.060ICU LOS, days2 (1-2)2 (1-4).14Hospital LOS, days6 (6-9)8 (6-11)<.00130-day mortality0 (0)11 (3.6).22Long-term outcomes, adjusted 15-Year death12 (19.7)122 (39.5).007ICU, Intensive care unit; LOS, length of stay; OAR, open aneurysm repair.Data presented as mean ± standard deviation, median (interquartile range), or number (%). Open table in a new tab

Is Mini-Invasive Surgery an Alternative for the Treatment of Juxtarenal Aortic Aneurysms?

Aim of our study is to evaluate the outcomes of mini-laparotomy, suprarenal cross-clamping, and enhanced recovery after elective open surgical repair for juxta-renal abdominal aortic aneurysms (JAAA) in a tertiary referral center. Data of all consecutive patients with abdominal aortic aneurysms (AAA) electively treated with left sub-costal mini-laparotomy requiring infrarenal or suprarenal cross-clamping between 2013 and 2018 were retrospectively collected. Patients were divided into two groups: infra-renal cross-clamping (group A) and JAAA requiring supra-renal cross-clamping (group B). Early and mid-term mortality, postoperative renal dysfunction according to RIFLE criteria and factors affecting postoperative outcome were analysed. Four hundred one patients, 356 (88.8%) men, mean age 70.8 yrs, underwent open surgical repair (OSR), 343 (85.5%) AAA in group A, 58 (14.5%) JAAA in group B. Mean diameter of the aneurysms was 54 ± 11.4 mm vs. 52 ± 9 mm and mean time of intervention 154.9 ± 56.3 min vs. 180.1 ± 65.7 min respectively. Total clamp time was 72.27 ± 31.4 vs. 75 ± 33.1 and suprarenal clamp time in group B 27.82 ± 14.1 min. Mean hospital length of stay was 5.1 ± 2.8 vs. 5.37 ± 3.4 days respectively. At 30 days, 3 (0.9%) patients died in group A and no one in group B; at 24 months 7 (2%) deaths in group A and 4 (6.9%) in group B. Preoperative, postoperative and discharge serum creatinine mean value, in group B, were 1.07 ± 0.32, 1.31 ± 0.36 and 1.83 ± 1.24 respectively. Based on RIFLE criteria for renal function, we observed Risk in 14.2% and Injury in 12.7% of patients after suprarenal cross clamping. Our results show that mini-invasive open repair for JAAA with a suprarenal cross-clamping can be performed with acceptable morbidity and mortality rates similar to traditional surgical approach without significant modifications of renal functions.

Incidence and predictors of early and delayed renal function decline after aortic aneurysm repair in the Vascular Quality Initiative database

BackgroundPostoperative acute kidney injury (AKI) may complicate both open and endovascular aortic aneurysm repair (EVAR) and is associated with substantial morbidity, mortality, and health care expense. We aim to evaluate the incidence of postoperative AKI and factors associated with its occurrence and the effects of postoperative AKI on long-term renal function and mortality after open and EVAR in the Society for Vascular Surgery Vascular Quality Initiative registry. MethodsElective aneurysm cases were identified including thoracic endovascular aortic aneurysm repair (TEVAR) and complex endovascular aortic aneurysm repair (cEVAR), infrarenal endovascular repair (EVAR) and infrarenal open repair (OAR) from 2003 to 2019. The preoperative estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease formula and stratified based on chronic kidney disease (CKD) grades. Postoperative AKI was defined per the Vascular Quality Initiative definition as a creatinine increase of 0.5 mg/dL or if postoperative dialysis was required. Patients on preprocedural hemodialysis and those with previous renal transplant were excluded. Demographics and procedural factors were evaluated for predicting in-hospital postoperative AKI (all approaches) and at 9 to 21 months of long-term follow-up (EVAR only) using logistic regression modeling. ResultsWe identified a total of 2813 cEVAR, 2995 TEVAR, 39,945 EVAR, and 8143 OAR patients. Of those, postoperative AKI occurred in 377 cEVAR (13.5%), 199 TEVAR (6.7%), 1099 EVAR (2.8%), and 1249 OAR (15.5%). Risk factors for postoperative AKI across all groups were worse preoperative eGFR, total number of blood transfusions, perioperative anemia, reinterventions, and postoperative respiratory complications. Additional procedure-specific risk factors of postoperative AKI were preoperative hemoglobin of less than 10 and contrast volume of 125 to 150 mL, hypertension, a low ejection fraction, and a history of percutaneous revascularization for EVAR; for both EVAR/cEVAR, renal artery coverage was a risk factor, whereas for OAR, male sex, non-White race, hypertension, suprarenal aortic cross-clamp, and increased renal ischemic time were risk factors. Among 8133 EVAR patients with long-term follow-up, a decrease in kidney function occurred in 56.7% of patients with postoperative AKI vs 19.9% without postoperative AKI (P < .001). The following risk factors were associated with a decrease in renal function at long-term follow-up: postoperative AKI, a preoperative eGFR of less than 90, and hypertension. A preoperative hemoglobin of greater than 12 was protective. Postoperative AKI was associated with significantly lower survival compared with no postoperative AKI across all procedures (log rank <0.001). ConclusionsPostoperative AKI occurs more often in patients with worse preoperative renal function, lower preoperative hemoglobin, and in open surgeries with inter-renal or suprarenal cross-clamping. Importantly, postoperative AKI is associated with increased mortality across all types of aortic repair. Given the long-term impact of postoperative AKI on outcomes for all aortic repairs and the limitations of current insensitive functional indices, there is a need to seek more sensitive indicators of decreases in early renal structural in this population.

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.

Cold Renal Perfusion During Simulation of Juxtarenal Aortic Aneurysm Repair Reduces Systemic Oxidative Stress and Sigmoid Damage in Rats

Juxtarenal aortic surgery induces renal ischaemia reperfusion, which contributes to systemic inflammatory tissue injury and remote organ damage. Renal cooling during suprarenal cross clamping has been shown to reduce renal damage. It is hypothesised that renal cooling during suprarenal cross clamping also has systemic effects and could decrease damage to other organs, like the sigmoid colon. Open juxtarenal aortic aneurysm repair was simulated in 28 male Wistar rats with suprarenal cross clamping for 45 min, followed by 20 min of infrarenal aortic clamping. Four groups were created: sham, no, warm (37 °C saline), and cold (4 °C saline) renal perfusion during suprarenal cross clamping. Primary outcomes were renal damage and sigmoid damage. To assess renal damage, procedure completion serum creatinine rises were measured. Peri-operative microcirculatory flow ratios were determined in the sigmoid using laser Doppler flux. Semi-quantitative immunofluorescence microscopy was used to measure alterations in systemic inflammation parameters, including reactive oxygen species (ROS) production in circulating leukocytes and leukocyte infiltration in the sigmoid. Sigmoid damage was assessed using digestive enzyme (intestinal fatty acid binding protein - I-FABP) leakage, a marker of intestinal integrity. Suprarenal cross clamping caused deterioration of all systemic parameters. Only cold renal perfusion protected against serum creatinine rise: 0.45 mg/dL without renal perfusion, 0.33 mg/dL, and 0.14 mg/dL (p = .009) with warm and cold perfusion, respectively. Microcirculation in the sigmoid was attenuated with warm (p = .002) and cold renal perfusion (p = .002). A smaller increase of ROS production (p = .034) was seen only after cold perfusion, while leukocyte infiltration in the sigmoid colon decreased after warm (p = .006) and cold perfusion (p = .018). Finally, digestive enzyme leakage increased more without (1.5AU) than with warm (1.3AU; p = .007) and cold renal perfusion (1.2AU; p = .002). Renal ischaemia/reperfusion injury after suprarenal cross clamping decreased microcirculatory flow, increased systemic ROS production, leukocyte infiltration, and I-FABP leakage in the sigmoid colon. Cold renal perfusion was superior to warm perfusion and reduced renal damage and had beneficial systemic effects, reducing sigmoid damage in this experimental study.

Comparison of Fenestrated Stentgrafts and Open Repair for Juxtarenal Aortic Aneurysms Using A Propensity Score Matching

Introduction: The purpose of this study is to compare the short- and mid-term results of fenestrated stentgrafts (FEVAR) and open repair (OR) for juxtarenal aortic aneurysms (JRAA). Methods: This cohort study was conducted in two tertiary centers between 2005 and 2017. Preoperative CT scans of patients who underwent FEVAR for complex abdominal AAA in both centers were reviewed by two experienced surgeons to select JRAA and exclude suprarenal and thoracoabdominal aneurysms. JRAA were defined as requiring suprarenal cross clamping but infrarenal proximal suture if treated by OR. Patients with JRAA treated by FEVAR were compared to patients with JRAA treated by OR using a propensity score matching. Propensity score was calculated on age, sex, smoking, diabetes, obesity, coronary artery disease, heart/renal/respiratory failure, ASA score, history of aortic surgery, aneurysm diameter and center. Results: Of 277 patients with JRAA, 102 (36,8%) received FEVAR and 175 (63,2%) received OR. Before propensity score matching, 30-day, in-hospital, 12 months and 36 months mortality rates were 5,9% / 5,9% / 17,5% / 27,8% (n= 6/n=6/n=17/n=27) in the FEVAR group and 1,7%/4%/6,5%/9,4% (n=3/n=7/n=11/n=16) in the OR group, respectively. After propensity score matching, 102 FEVAR patients (66,7%) and 51 OR patients (33,3%) were included in the analysis. 30-day and in-hospital mortality rates were 5.9% (N = 6) in the FEVAR group vs. 3,9% (N=2) / 7,8% (N=4) in the OR group (p=0,61 / p=0,64). The median follow-up period was 40 months (range: 0,2-112) in the FEVAR group and 41 months (range: 1-149) in the OR group. During follow-up, overall mortality at 12 months was similar in both groups (FEVAR: 17,7% vs. OR: 12 %, p = 0,31). At 36 months, there was a non-significant trend towards higher overall mortality rates in the FEVAR group (27,1% vs. 14,0%, p = 0,07). FEVAR- patients experienced significantly fewer moderate to severe complications (FEVAR group: n=19, 18,8%; OR group: n=21, 41,2%, Odd Ratio = 0,32; 95% CI: 0.15-0.71; p = 0,05), especially renal (18,0% vs. 26,0%; p = 0,005) and respiratory (4,9% vs. 17,7%; p = 0,029). In total, twenty-five patients required reintervention (16,4%), with no difference between the two groups (FEVAR: 16,7% vs. OR: 15,7%, p = 0,88). In the FEVAR group, two aortic ruptures occurred during follow-up. Persistent endoleak was observed in 17 patients (16,7%) in the FEVAR group (3 type IA, 13 type II and 1 unclassified). Conclusion: This comparative study did not show a significant difference in mid-term mortality, although a trend towards higher mortality rates was observed at 36 months in the FEVAR group. Moderate to severe complications, especially renal and respiratory, were more frequent in the OR group. Propensity score matching mainly selected the most fragile patients in the OR group. This study highlights the need for a randomized study to compare FEVAR and OR for juxtarenal AAA. Disclosure: Frederic Cochennec is a proctor for Cook MEdical

Cold Renal Perfusion During Simulation of Juxtarenal Aortic Aneurysm Repair Reduces Systemic Oxidative Stress and Sigmoid Damage in Rats

Juxtarenal aortic surgery induces renal ischaemia reperfusion, which contributes to systemic inflammatory tissue injury and remote organ damage. Renal cooling during suprarenal cross clamping has been shown to reduce renal damage. It is hypothesised that renal cooling during suprarenal cross clamping also has systemic effects and could decrease damage to other organs, like the sigmoid colon. Open juxtarenal aortic aneurysm repair was simulated in 28 male Wistar rats with suprarenal cross clamping for 45min, followed by 20min of infrarenal aortic clamping. Four groups were created: sham, no, warm (37°C saline), and cold (4°C saline) renal perfusion during suprarenal cross clamping. Primary outcomes were renal damage and sigmoid damage. To assess renal damage, procedure completion serum creatinine rises were measured. Peri-operative microcirculatory flow ratios were determined in the sigmoid using laser Doppler flux. Semi-quantitative immunofluorescence microscopy was used to measure alterations in systemic inflammation parameters, including reactive oxygen species (ROS) production in circulating leukocytes and leukocyte infiltration in the sigmoid. Sigmoid damage was assessed using digestive enzyme (intestinal fatty acid binding protein - I-FABP) leakage, a marker of intestinal integrity. Suprarenal cross clamping caused deterioration of all systemic parameters. Only cold renal perfusion protected against serum creatinine rise: 0.45mg/dL without renal perfusion, 0.33mg/dL, and 0.14mg/dL (p=.009) with warm and cold perfusion, respectively. Microcirculation in the sigmoid was attenuated with warm (p=.002) and cold renal perfusion (p=.002). A smaller increase of ROS production (p=.034) was seen only after cold perfusion, while leukocyte infiltration in the sigmoid colon decreased after warm (p=.006) and cold perfusion (p=.018). Finally, digestive enzyme leakage increased more without (1.5AU) than with warm (1.3AU; p=.007) and cold renal perfusion (1.2AU; p=.002). Renal ischaemia/reperfusion injury after suprarenal cross clamping decreased microcirculatory flow, increased systemic ROS production, leukocyte infiltration, and I-FABP leakage in the sigmoid colon. Cold renal perfusion was superior to warm perfusion and reduced renal damage and had beneficial systemic effects, reducing sigmoid damage in this experimental study.

Administration of Tetrahydrobiopterin (BH4) Protects the Renal Microcirculation From Ischemia and Reperfusion Injury.

Abdominal aortic aneurysm surgery with suprarenal cross-clamping is often associated with renal injury. Although the mechanism underlying such injury is unclear, tissue ischemia and reperfusion, which induces endothelial dysfunction and decreases the availability of tetrahydrobiopterin (BH4), may play a role. We evaluated whether BH4 administration prevents renal ischemia/reperfusion injury in an animal model of aortic cross-clamping. Nineteen anesthetized, mechanically ventilated, and invasively monitored adult sheep were randomized into 3 groups: sham animals (n = 5) that underwent surgical preparation but no aortic clamping; an ischemia/reperfusion group (n = 7), where the aorta was clamped above the renal arteries for 1 hour, and a BH4 group (n = 7), in which animals received 20 mg/kg of BH4 followed by aortic cross-clamp for 1 hour. Animals were followed for a maximum of 6 hours after reperfusion. The renal microcirculation was evaluated at baseline (before clamping), and 1, 4, and 6 hours after reperfusion using side-stream dark field videomicroscopy. The renal lactate-to-pyruvate ratio was evaluated using microdialysis. The primary outcome was the change in proportion of small perfused vessels before and after injury. Secondary outcomes were renal tissue redox state and renal function. Ischemia/reperfusion injury was associated with increases in heart rate and mean arterial pressure, which were blunted by BH4 administration. From the first to the sixth hour after reperfusion, the small vessel density (estimated mean difference [EMD], 1.03; 95% confidence interval [CI], 0.41-1.64; P = .003), perfused small vessel density (EMD, 0.84; 95% CI, 0.29-1.39; P = .005), and proportion of perfused small vessels (EMD, 8.60; 95% CI, 0.85-16.30; P = .031) were altered less in the BH4 than in the ischemia/reperfusion group. The renal lactate-to-pyruvate ratios were lower in the cortex in the BH4 than in the ischemia/reperfusion group from the first to the sixth hour after reperfusion (EMD, -19.16; 95% CI, -11.06 to 33.16; P = .002) and in the medulla from the first to the fourth hour (EMD, -26.62; 95% CI, -18.32 to 38.30; P = .020; and EMD, -8.68; 95% CI, -5.96 to 12.65; P = .019). At the sixth hour, serum creatinine was lower in the BH4 than in the ischemia/reperfusion group (EMD, -3.36; 95% CI, -0.29 to 1.39; P = .026). In this sheep model of renal ischemia/reperfusion, BH4 pretreatment reduced renal microvascular injury and improved renal metabolism and function. Further work is needed to clarify the potential role of BH4 in ischemia/reperfusion injury.

Prevention of renal injury due to suprarenal cross-clamping with ischemic preconditioning and carnitine: an experimental study

Prevention of renal injury due to suprarenal cross-clamping with ischemic preconditioning and carnitine: an experimental study

Treatment of Hostile Proximal Necks During Endovascular Aneurysm Repair.

Endovascular aneurysm repair (EVAR) is a therapy that continues to evolve rapidly as advances in technology are incorporated into new generations of devices and surgical practice. Although EVAR has emerged as a safe and effective treatment for patients with favorable anatomy, treatment of patients with unfavorable anatomy remains controversial and is still an off-label indication for endovascular treatment with some current stent-grafts. The proximal neck of the aneurysm remains the most hostile anatomic barrier to successful endovascular repair with long-term durability. Open surgery for unfavorable necks is still considered the gold standard treatment in contemporary practice, despite the increased mortality and morbidity attributed to suprarenal cross-clamping, particularly in high-risk patients. Evolving technology may overcome the obstacles preventing endovascular treatment of unfavorable proximal neck anatomy; current approaches include purely endovascular as well as hybrid approaches, and generally include strategies that either extend the length of the short neck, move the proximal neck more proximally, or keep the short neck intact. These approaches include the use of debranching techniques, banding, chimneys, fenestrated and branched devices, filling the sac with endobags, endoanchors, and other novel devices. These newer-generation devices appear to have promising short- and midterm results. However, lack of good evidence of efficacy with long-term results for these newer approaches still precludes wide dissemination of endovascular solutions for the hostile proximal neck.

Evolución de la función renal en la cirugía del aneurisma de aorta abdominal con clampaje suprarrenal

ObjectiveTo analyse the effects of suprarenal cross-clamping (SC) as opposed to the infrarenal position (IC) in the evolution of the renal function abdominal aorta aneurysm (AAA) surgery. Material and methodA retrospective cohort study of AAAs treated by elective open surgery between 1998 and 2011. The preoperative level of serum creatinine (mg/dL) was determined and compared to postoperative level at 24, 48, 72 and 96hours, and on discharge. A deterioration in the renal function was defined as a creatinine > 2mg/dL in patients with a normal baseline creatinine level or an increase of double the baseline creatinine in patients with a previous chronic renal insufficiency (CRI). A deterioration of the glomerular filtrate (GF) was defined as a > 25% decrease. Multivariable analysis was performed on the evolution of the renal function. ResultsA total of 464 AAA's were analysed, 359 (77.4%) with IC, and 105 (22.6%) with SC. The prevalence of preoperative CRI was similar in both groups. The type of clamp was not associated with a deterioration in the renal function (SC=8.6% vs. IC=5.7%; p=.13) but was associated with a deterioration of the GF (SC=27.6% vs. IC=13.4%; p=.001). The time the clamp was in place, the blood loss, and the preoperative CRI were independent risk factors for the deterioration of the renal function. The type of clamp increased the risk of deterioration of the renal function beyond 30minutes (p=.001), being independently associated with a deterioration in the GF (OR 2.04; 95% CI: 0.94-4.47). ConclusionWith SC less than 30min, in patients with a creatinine level, a deterioration in the renal function is not foreseeable. With prior CRI, or if a prolonged SC is foreseen, a deterioration in the renal function can be expected, thereby making it necessary to evaluate methods for renal protection.

Postoperative Renal Function After Juxtarenal Aortic Aneurysm Repair With Simple Cross-Clamping

We report our 11-year experience of juxtarenal aortic aneurysm (JAA) repair with suprarenal aortic cross-clamping. We retrospectively reviewed 51 consecutive JAA repairs performed between 2000 and 2010. In all 51 patients, aneurysms were replaced by prosthetic grafts with simple suprarenal aortic cross-clamping. No special renal protective measures (except inter-renal cross-clamping) were performed during interruption of perfusion to kidneys. For inter-renal cross-clamping, the aortic cross-clamp was placed from below one renal artery to above the other renal artery to maintain hemilateral renal perfusion. This technique was applied in 27 patients (54%). Postoperative complications, renal function, and survival were evaluated. There were no deaths. The average renal ischemia time was 28.9 ± 9.7 minutes. Postoperatively, transient renal failure (defined as an estimated glomerular filtration rate of <30 mL/min/1.73 m(2)) occurred in 14% of the patients. The postoperative decrease of estimated glomerular filtration rate compared with the preoperative value was significantly smaller in the inter-renal clamp group (7.4% ± 16%) than in the suprarenal clamp group (17.5% ± 16%) (P < 0.05, unpaired t test). However, renal dysfunction was temporary and recovered to baseline before discharge with conservative therapy in all patients except one. In addition, renal function was generally preserved at 1 year after surgery. Surgical repair of JAA can be performed with simple cross-clamping and an acceptable renal ischemic time, achieving excellent results. Inter-renal cross-clamping reduces renal damage compared with suprarenal cross-clamping.

Increasing Complexity in the Open Surgical Repair of Abdominal Aortic Aneurysms

Patient selection and techniques for the operative management of abdominal aortic aneurysms (AAAs) continue to evolve. We sought to examine trends in open surgical repair (OSR) over a 15-year period in which endovascular aneurysm repair (EVAR) has become increasingly prevalent. Patients undergoing elective repair of infra- and pararenal AAAs were identified through our center's prospective vascular surgery registry during two time periods: 1995 to 2004 (era 1) and 2004 to 2010 (era 2). Data collected included comorbidities, demographics, and operative characteristics. A total of 1,188 elective AAAs were repaired during the study period, including 828 (70%) OSRs and 360 (30%) EVARs. The proportion of OSRs requiring suprarenal cross-clamping increased from 14.2% during era 1 to approximately 50% by the end of era 2. Compared with era 1, increases were seen in the unadjusted mortality rates during era 2 for OSR with infrarenal clamping (from 0.62% to 1.73%) and OSR with suprarenal clamping (from 1.22% to 3.98%); after adjusting for other variables, however, no significant temporal trends were seen. Similarly, no significant change in major complication rate was seen after adjusting for other factors. The incidence of major comorbidities among the OSR group was largely unchanged between the two eras. OSR of AAAs has become increasingly complex, with the increased utilization of EVAR. Despite this complexity, risk-adjusted outcomes may remain good in high-volume centers.

Laparoscopic-assisted treatment of abdominal aortic aneurysm requiring suprarenal cross-clamping

Hand-assisted laparoscopic surgery (HALS) was previously employed to treat patients with infrarenal abdominal aortic aneurysm (IAAA). The use of HALS for juxtarenal abdominal aortic aneurysm (JAAA) has never been validated. In this study, we report our experience with this technique to demonstrate its feasibility and prove its safety in dealing with JAAA. From October 2000 to October 2008, we have selectively treated 271 patients with abdominal aortic aneurysm with the HALS technique. Of these, 83 were JAAAs which required a suprarenal aortic clamping (group A), and 188 were IAAA (group B). General data of the two groups were analyzed for comparability purposes and operative and postoperative data were prospectively collected. Additionally, patients in group A were stratified in three classes according to their pre-existing degree of renal function impairment. Statistical significance was defined at the P < .05 level. Mean operative time was 220 minutes +/- 66 in group A and 231 minutes +/- 64 in group B (P > .05). The mean duration of suprarenal clamping was 28 minutes +/- 6; whereas infrarenal clamping lasted an average of 25 minutes +/- 5 (P > .05). Mean intraoperative blood loss was 1023 +/- 584 mL for group A and 961 +/- 633 mL for group B (P > .05). No conversion or 30-day postoperative mortality was recorded in either group. Sixteen percent of the patients in group A developed a postoperative complication, vs 11% in group B (P > .05). Mean postoperative stay for group A and B was 4.2 +/- 1.5 and 4.2 +/- 1.9 days, respectively (P > .05). Postoperative kidney function significantly worsened in 5 patients in group A (6%). A prolonged warm ischemia time (>40), pre-existing renal dysfunction, and diabetes, correlated to the development of postoperative renal insufficiency. Follow-up of patients averaged 37.9 +/- 20 months. The incidence of incisional hernias in group A and B was 15.5% vs 11.1%, respectively (P > .05). The HALS technique proved to be feasible and safe not only for patients with IAAA, but also for the management of patients with JAAA. No significant difference could be shown in the comparison between the two groups, apart from the expected higher rate of postoperative renal dysfunction after suprarenal clamping. In view of the demonstrated benefit of this minimally invasive approach, we believe that it should be included among the alternative options of treatment for these patients.

Open Abdominal Aortic Aneurysm Repair in the Endovascular Era

To describe a contemporary series of open abdominal aortic aneurysm (AAA) repairs in patients not anatomically suitable for endovascular AAA repair. A prospectively maintained database including consecutive nonruptured open aneurysm repairs from March 1, 2000, through July 31, 2007, was reviewed. Patient demographic characteristics and perioperative outcomes were evaluated and stratified based on proximal aortic cross-clamp placement. A total of 185 patients with AAA underwent 103 infrarenal and 82 suprarenal cross-clamp repairs. Overall, the complication rate was 37.0% with infrarenal and 61.0% with suprarenal cross-clamps (P = .001). The 30-day mortality was 2.9% with infrarenal and 6.1% with suprarenal cross-clamps (P = .18). Postoperative renal insufficiency (29.3% vs 7.8%; P < .001) and pulmonary complications (25.6% vs 12.6%; P = .03) were more frequent with suprarenal cross-clamps. Suprarenal cross-clamps were associated with greater intraoperative blood loss (2586 mL vs 1638 mL; P = .006), operative duration (391 min vs 355 min; P = .005), use of adjunctive renal and/or visceral grafts (43.9% vs 1.9%; P < .001), duration of intensive care unit stay (4.5 days vs 3.0 days; P = .006), and hospital length of stay (9 days vs 7 days; P = .04). Of patients who received a suprarenal cross-clamp, 25.6% required temporary nursing home placement vs 17.5% with an infrarenal cross-clamp (P = .14). Until fenestrated and branched endografts are available, open AAA repairs will become increasingly complex. Suprarenal cross-clamping is associated with increased rates of complications but similar mortality rates and need for nursing home placement. With the disappearance of straightforward open aneurysm repair, trainees in vascular surgery will have to learn AAA repair almost exclusively by operating on patients with complex AAAs. Fewer surgeons will perform these repairs, and fewer fellows will be able to complete the operation independently immediately after training.

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.

Statin use is associated with early recovery of kidney injury after vascular surgery and improved long-term outcome

Acute kidney injury (AKI) after major vascular surgery is an important risk factor for adverse long-term outcomes. The pleiotropic effects of statins may reduce kidney injury caused by perioperative episodes of hypotension and/or suprarenal clamping and improve long-term outcomes. Of 2170 consecutive patients undergoing lower extremity bypass or abdominal aortic surgery from 1995 to 2006, cardiac risk factors and medication were noted. A total of 515/1944 (27%) patients were statin users. Creatinine clearance (CrCl) was assessed preoperatively at 1, 2 and 3 days after surgery. Outcome measures were postoperative AKI and long-term mortality. Postoperative kidney injury was defined as a >10% decrease in CrCl on Day 1 or 2, compared to the baseline. Recovery of kidney function was defined as a CrCl >90% of the baseline value at Day 3 after surgery. Multivariable Cox regression analysis, including baseline cardiovascular risk factors, baseline CrCl and propensity score for statin use, was applied to evaluate the influence of statins on early postoperative kidney injury and long-term survival. AKI occurred in 664 (34%) patients [median -25% CrCl, range (-10% to -71%)]. Of these 664 patients, 313 (47%) had a complete recovery of kidney function at Day 3 after surgery. Age, hypertension, suprarenal cross-clamping and baseline CrCl predicted the development of kidney injury during the postoperative period. The incidence of kidney injury was similar among statin users and non-users (29% versus 25%, OR 1.15, 95% CI 0.9-1.5). However, if kidney function deteriorated, statin use was associated with increased odds of complete kidney function recovery (OR 2.0, 95% CI 1.0-3.8). During a mean follow-up of 6.24 years, half of the patients died (55%). Importantly, statin use was also associated with an improved long-term survival, irrespective of kidney function change (HR 0.60, 95% CI 0.48-0.75). Statin use is associated with improved recovery from AKI after major surgery and has a beneficial effect on long-term survival.