Elevated Renal Oxygen Extraction During Open Abdominal Aortic Aneurysm Repair Is Related to Postoperative Renal Dysfunction.

BACKGROUND: Open abdominal aortic aneurysm repair is often followed by elevated plasma creatinine, likely due to impaired renal blood flow. We evaluated whether postoperative elevation in creatinine relates to renal oxygen extraction during surgery as an index of renal blood flow and also monitored frontal lobe oxygenation. METHODS: For 19 patients (66 ± 10 years; mean ± SD) undergoing open infrarenal abdominal aortic aneurysm repair, renal oxygen extraction was determined by arterial and renal vein catheterization. Near-infrared spectroscopy determined frontal lobe oxygenation. RESULTS: During surgery mean arterial pressure (from 102 ± 14 to 65 ± 11 mm Hg; P < .0001), arterial hemoglobin (from 7.7 ± 0.7 to 6.6 ± 0.8 mmol/L; P < 0.0001), and frontal lobe oxygenation (from 74 ± 6% to 70 ± 6%; P = .0414) decreased, while renal oxygen extraction increased (from 5.3% [4.3-8.1]; median [interquartile range] to 10.8% [5.8-17.5]; P = .0405). Plasma creatinine became significantly elevated on the second day after the operation (from 83 [73-101] to 105 µmol/L [79-143]; P = .0062) with a peak increase observed after 2 days (1-2). The peak increase in creatinine correlated to intraoperative renal oxygen extraction ( r = 0.51; P = .026). CONCLUSION: Kidney function was affected after open abdominal aortic aneurysm repair likely related to limited renal blood flow. We take the increase in renal oxygen extraction and reduction in frontal lobe oxygenation to suggest that mean arterial pressure and hemoglobin were too low to maintain renal and cerebral circulation in vascular surgical patients.

ADRB2 gly16gly Genotype, Cardiac Output, and Cerebral Oxygenation in Patients Undergoing Anesthesia for Abdominal Aortic Aneurysm Surgery.

BACKGROUND: Gly16arg polymorphism of the adrenergic ß2-receptor is associated with the elevated cardiac output (Q) in healthy gly16-homozygotic subjects. We questioned whether this polymorphism also affects Q and regional cerebral oxygen saturation (SCO2) during anesthesia in vascular surgical patients. METHODS: One hundred sixty-eight patients (age 71 ± 6 years) admitted for elective surgery were included. Cardiovascular variables were determined before and during anesthesia by intravascular pulse contour analysis (Nexfin) and SCO2 by cerebral oximetry (INVOS 5100C). Genotyping was performed with the TaqMan assay. RESULTS: Before anesthesia, Q and SCO2 were 4.7 ± 1.2 L/min and 66% ± 8%, respectively, and linearly correlated (r = 0.35, P < .0001). In patients with the gly16gly genotype baseline, Q was approximately 0.4 L/min greater than in arg16 carriers (CI95: 0.0-0.8, Pt test = .03), but during anesthesia, the difference was 0.3 L/min (Pmixed-model = .07). Post hoc analysis revealed the change in SCO2 from baseline to the induction of anesthesia to be on average 2% greater in gly16gly homozygotes than in arg16 patients when adjusted for the change in Q (P = .03; CI95: 0.2-4.0%). CONCLUSIONS: This study suggests that the ß2-adrenoceptor gly16gly genotype is associated with the elevated resting Q. An interesting trend to greater frontal lobe oxygenation at induction of anesthesia in patients with gly16gly genotype was found, but because of insufficient sample size and lack of PCO2 control throughout the measurements, the presented data may only serve as the hypothesis generating for future studies. The confidence limits indicate that the magnitude of the effects may range from clinically insignificant to potentially important.

[Lower extremity arterial entrapment syndromes]. / Arterielle afklemningssyndromer i underekstremiteterne.

Iliac endofibrosis or iliac kinking and popliteal artery entrapment syndrome are uncommon causes of arterial insufficiency and intermittent claudication in young physically active adults. Diagnostics can be difficult, as the symptoms often are confused with sport injuries and musculoskeletal disorders. Investigation of these patients relies on accurate clinical history and examination as well as both static and dynamic imaging. Early diagnosis and vascular intervention is essential for continued exercise and to prevent thromboembolic complications and, in worst case, limb loss.

Popliteal artery entrapment syndrome: ultrasound imaging, intraoperative findings, and clinical outcome.

OBJECTIVES: The purpose of this study was to report our experience with popliteal artery entrapment syndrome (PAES) with special emphasis on the applicability of duplex ultrasound scanning (DUS) when diagnosing PAES. In addition to examining the correlation between DUS and intraoperative findings in symptomatic limbs, the ultrasonic effect of plantar flexion in healthy volunteers were also evaluated. METHODS: During a 12-month period, 11 symptomatic limbs in 8 patients with a mean age of 29 years were referred with suspected PAES and enrolled consecutively. The popliteal artery was studied preoperatively with DUS in rest and during active plantar flexion. The popliteal artery was explored in all symptomatic limbs, and the intraoperative findings served as gold standard. Additionally, the popliteal arteries in 11 healthy volunteers (22 limbs) were evaluated with DUS during rest and plantar flexion. RESULTS: Intraoperative findings confirmed PAES in all 11 symptomatic limbs in accordance with the preoperative DUS examination. Surgical release of the popliteal artery was performed in 11 limbs. At a median follow-up of 15 months, all 11 limbs were free of ischemic symptoms and regained normalized popliteal flow on DUS. In the 22 symptom-free limbs, DUS showed normal popliteal flow during both rest and plantar flexion. CONCLUSIONS: In this series of patients with surgically confirmed PAES, we found preoperative DUS to have perfect agreement with the intraoperative findings in diagnosing PAES. The applicability of the method seems to be emphasized by the restoration of popliteal flow and relief of arterial insufficiency after surgical release in all patients, and by the fact, that none of the healthy volunteers were able to compress the popliteal artery during plantar flexion.