Contemporary outcomes after treatment of aberrant subclavian artery and Kommerell's diverticulum.

OBJECTIVE: Aberrant subclavian artery (ASA) and Kommerell's diverticulum (KD) are rare vascular anomalies that may be associated with lifestyle-limiting and life-threatening complications. The aim of this study is to report contemporary outcomes after invasive treatment of ASA/KD using a large international dataset. METHODS: Patients who underwent treatment for ASA/KD (2000-2020) were identified through the Vascular Low Frequency Disease Consortium, a multi-institutional collaboration to investigate uncommon vascular disorders. We report the early and mid-term clinical outcomes including stroke and mortality, technical success, and other operative outcomes including reintervention rates, patency, and endoleak. RESULTS: Overall, 285 patients were identified during the study period. The mean patient age was 57 years; 47% were female and 68% presented with symptoms. A right-sided arch was present in 23%. The mean KD diameter was 47.4 mm (range, 13.0-108.0 mm). The most common indication for treatment was symptoms (59%), followed by aneurysm size (38%). The most common symptom reported was dysphagia (44%). A ruptured KD was treated in 4.2% of cases, with a mean diameter of 43.9 mm (range, 18.0-100.0 mm). An open procedure was performed in 101 cases (36%); the most common approach was ASA ligation with subclavian transposition. An endovascular or hybrid approach was performed in 184 patients (64%); the most common approach was thoracic endograft and carotid-subclavian bypass. A staged operative strategy was employed more often than single setting repair (55% vs 45%). Compared with endovascular or hybrid approach, those in the open procedure group were more likely to be younger (49 years vs 61 years; P < .0001), female (64% vs 36%; P < .0001), and symptomatic (85% vs 59%; P < .0001). Complete or partial symptomatic relief at 1 year after intervention was 82.6%. There was no association between modality of treatment and symptom relief (open 87.2% vs endovascular or hybrid approach 78.9%; P = .13). After the intervention, 11 subclavian occlusions (4.5%) occurred; 3 were successfully thrombectomized resulting in a primary and secondary patency of 95% and 96%, respectively, at a median follow-up of 39 months. Among the 33 reinterventions (12%), the majority were performed for endoleak (36%), and more reinterventions occurred in the endovascular or hybrid approach than open procedure group (15% vs 6%; P = .02). The overall survival rate was 87.3% at a median follow-up of 41 months. The 30-day stroke and death rates were 4.2% and 4.9%, respectively. Urgent or emergent presentation was independently associated with increased risk of 30-day mortality (odds ratio [OR], 19.8; 95% confidence interval [CI], 3.3-116.6), overall mortality (OR, 3.6; 95% CI, 1.2-11.2) and intraoperative complications (OR, 8.3; 95% CI, 2.8-25.1). Females had a higher risk of reintervention (OR, 2.6; 95% CI, 1.0-6.5). At an aneurysm size of 44.4 mm, receiver operator characteristic curve analysis suggested that 60% of patients would have symptoms. CONCLUSIONS: Treatment of ASA/KD can be performed safely with low rates of mortality, stroke and reintervention and high rates of symptomatic relief, regardless of the repair strategy. Symptomatic and urgent operations were associated with worse outcomes in general, and female gender was associated with a higher likelihood of reintervention. Given the worse overall outcomes when symptomatic and the inherent risk of rupture, consideration of repair at 40 mm is reasonable in most patients. ASA/KD can be repaired in asymptomatic patients with excellent outcomes and young healthy patients may be considered better candidates for open approaches versus endovascular or hybrid modalities, given the lower likelihood of reintervention and lower early mortality rate.

International Multi-Institutional Experience with Presentation and Management of Aortic Arch Laterality in Aberrant Subclavian Artery and Kommerell's Diverticulum.

BACKGROUND: Aberrant subclavian artery (ASA) with or without Kommerell's diverticulum (KD) is a rare anatomic aortic arch anomaly that can cause dysphagia and/or life-threatening rupture. The objective of this study is to compare outcomes of ASA/KD repair in patients with a left versus right aortic arch. METHODS: Using the Vascular Low Frequency Disease Consortium methodology, a retrospective review was performed of patients ≥18 years old with surgical treatment of ASA/KD from 2000 to 2020 at 20 institutions. RESULTS: 288 patients with ASA with or without KD were identified; 222 left-sided aortic arch (LAA), and 66 right-sided aortic arch (RAA). Mean age at repair was younger in LAA 54 vs. 58 years (P = 0.06). Patients in RAA were more likely to undergo repair due to symptoms (72.7% vs. 55.9%, P = 0.01), and more likely to present with dysphagia (57.6% vs. 39.1%, P < 0.01). The hybrid open/endovascular approach was the most common repair type in both groups. Rates of intraoperative complications, death within 30 days, return to the operating room, symptom relief and endoleaks were not significantly different. For patients with symptom status follow-up data, in LAA, 61.7% had complete relief, 34.0% had partial relief and 4.3% had no change. In RAA, 60.7% had complete relief, 34.4% had partial relief and 4.9% had no change. CONCLUSIONS: In patients with ASA/KD, RAA patients were less common than LAA, presented more frequently with dysphagia, had symptoms as an indication for intervention, and underwent treatment at a younger age. Open, endovascular and hybrid repair approaches appear equally effective, regardless of arch laterality.

Closure of a surgically created arteriovenous fistula with a covered stent-graft in a patient with venous ambulatory hypertension--a case report.

The purpose of this paper is to report the use of a covered stent-graft in the endovascular treatment of a surgically created arteriovenous fistula. A 37-year-old woman with symptomatic venous ambulatory hypertension underwent a left common femoral vein-to-right common iliac vein bypass using 10 mm ringed polytetrafluoroethylene (PTFE) with creation of an arteriovenous (AV) fistula from the superficial femoral artery to the PTFE graft. At 1 year postoperatively, recurrent symptoms thought to be due to the arteriovenous fistula were treated by placement of an 8 mm x 10 cm Viabahn covered stent-graft. Placement was via crossover technique from the right common femoral artery using a 9 French sheath. At 2 months' follow-up symptoms had resolved, the AV fistula was occluded, and venous bypass remained patent. Focal arteriovenous fistulas of the proximal superficial femoral artery can be treated safely with a covered stent-graft via an endovascular approach.

Superior vena cava perforation and cardiac tamponade after filter placement in the superior vena cava--a case report.

The purpose of this paper is to report the complication of perforation of the superior vena cava (SVC) leading to cardiac tamponade after the insertion of a Trapease IVC filter in the SVC position. A 29-year-old man was hit by motor vehicle and sustained numerous injuries including a left skull fracture, intracerebral hemorrhage, and left open tibial shaft fracture. During his hospitalization, he developed an extensive symptomatic right upper extremity deep venous thrombosis involving the brachial, axillary, subclavian, internal jugular, and brachiocephalic veins. Owing to an intracerebral bleed, anticoagulation was contraindicated. Therefore, a Trapease filter (Cordis Inc.) was placed in the SVC via the left subclavian vein. Four hours later, the patient became hypotensive with associated tachycardia and tachypnea. Computed tomography of his chest revealed a hematoma around the SVC, a moderate amount of fluid within the pericardium, and a moderate-sized right pleural effusion. The patient was taken to the operating room and a pericardial window was performed. Approximately 500 cc of blood was evacuated from the pericardium and immediate improvement in vital signs was noted. The patient was discharged from the hospital 2 weeks later and at 6-month follow-up had made full recovery. This is the first case of SVC perforation leading to cardiac tamponade after the insertion of a Trapease filter. Owing to the rigid structure of the filter and associated motion of the SVC and pericardium, the Trapease filter may be contraindicated in the SVC.

Morbidity and mortality after extent II thoracoabdominal aortic aneurysm repair.

BACKGROUND: Surgical repair of Crawford extent II thoracoabdominal aortic aneurysms (TAAAs) carries substantial risk for morbidity and mortality. The purpose of this study was to analyze the results of a large consecutive series of extent II TAAA repairs and identify factors that influence morbidity and survival. METHODS: Of 1,415 consecutive patients who underwent TAAA operations over a 13-year period, 442 (31.2%) had extent II repairs. Data from a prospectively maintained database were analyzed to determine which factors were associated with death and major complications. RESULTS: The operative mortality was 10.0% (44 patients). Postoperative complications included paraplegia/paraparesis in 33 patients (7.5%), pulmonary complications in 158 (35.7%), and renal failure in 69 (15.9%). Multivariable analysis revealed that renal insufficiency (odds ratio [OR] 2.6), increasing age (OR 1.1/year), and increasing red blood cell transfusion requirements (OR 1.1/U) were predictors for mortality; renal insufficiency (OR 2.8) and peptic ulcer disease (OR 9.3) were predictors of renal failure; and rupture (OR 6.3) was a predictor of paraplegia. Left heart bypass was an independent protective factor against paraplegia (OR 0.4). CONCLUSIONS: This contemporary experience demonstrates acceptable levels of morbidity and mortality in this high-risk group. Left heart bypass was found to provide protection against paraplegia in these patients.

Estimating group mortality and paraplegia rates after thoracoabdominal aortic aneurysm repair.

BACKGROUND: Most clinical studies regarding thoracoabdominal aortic aneurysm (TAAA) surgery are retrospective comparisons involving heterogeneous groups of patients. Risk models that evaluate susceptibility bias enhance interpretation of these intergroup comparisons. The purpose of this analysis was to derive group risk models for mortality and paraplegia after TAAA repair. METHODS: Data regarding 1,220 consecutive patients undergoing TAAA repair were analyzed via multiple logistic regression with stepwise model selection. Categorical preoperative risk factors that predicted 30-day mortality and paraplegia were used to develop risk models. RESULTS: Fifty-eight patients (4.8%) died within 30 days and 56 patients (4.6%) developed paraplegia or paraparesis. Predictors of mortality were rupture, renal insufficiency, symptomatic aneurysms, and Crawford extent II repairs. Extent of repair and acute presentation were predictors of paraplegia. The derived risk models estimated mortality and paraplegia rates that correlated well with actual frequencies reported in other contemporary series (regression slopes = 0.87 and 1.06, respectively). CONCLUSIONS: The derived risk models accurately estimate paraplegia and mortality rates in groups of patients. Prospective model validation will be required to confirm their accuracy.

BioGlue surgical adhesive impairs aortic growth and causes anastomotic strictures.

BACKGROUND: BioGlue surgical adhesive (CryoLife, Inc, Kennesaw, GA) is currently being used to secure hemostasis at cardiovascular anastomoses in adults. Interference with vessel growth would preclude its use during congenital heart surgery. The purpose of this study was to determine if BioGlue reinforcement of aortic anastomoses impairs vessel growth and causes strictures. METHODS: Ten 4-week-old piglets (8.0 +/- 1.4 kg) underwent primary aorto-aortic anastomoses. Five piglets were randomly assigned to anastomotic reinforcement with BioGlue. After a 7-week growth period, the aortas were excised for morphometric analysis and histopathology. RESULTS: Weight gains were similar in both groups. In BioGlue animals, however, aortic circumference increased only 1.5 +/- 0.8 mm (versus 2.7 +/- 0.8 mm in controls; p = 0.054). BioGlue animals developed a 33.9% stenosis of the aortic lumen area (versus 3.7% in controls, p = 0.038). Adventitial changes reflecting tissue injury and fibrosis were present in all BioGlue animals versus none of the control animals (p = 0.008). CONCLUSIONS: BioGlue reinforcement impairs vascular growth and causes stricture when applied circumferentially around an aorto-aortic anastomosis. This adhesive should not be used on cardiovascular anastomoses in pediatric patients.

Renal perfusion during thoracoabdominal aortic operations: cold crystalloid is superior to normothermic blood.

BACKGROUND: Renal failure remains a common complication of thoracoabdominal aortic aneurysm repair. The purpose of this randomized clinical trial was to compare two methods of selective renal perfusion--cold crystalloid perfusion versus normothermic blood perfusion--and determine which technique provides the best kidney protection during thoracoabdominal aortic aneurysm repair. METHODS: Thirty randomized patients undergoing Crawford extent II thoracoabdominal aortic aneurysm repair with left heart bypass had renal artery perfusion with either 4 degrees C Ringer's lactate solution (14 patients) or normothermic blood from the bypass circuit (16 patients). Acute renal dysfunction was defined as an elevation in serum creatinine level exceeding 50% of baseline within 10 postoperative days. RESULTS: One death occurred in each group. One patient in the blood perfusion group experienced renal failure requiring hemodialysis. Ten patients (63%) in the blood perfusion group and 3 patients (21%) in the cold crystalloid perfusion group experienced acute renal dysfunction (p = 0.03). Multivariable analysis confirmed that the use of cold crystalloid perfusion was independently protective against acute renal dysfunction (p = 0.02; odds ratio, 0.133). CONCLUSIONS: When using left heart bypass during repair of extensive thoracoabdominal aortic aneurysms, selective cold crystalloid perfusion offers superior renal protection when compared with conventional normothermic blood perfusion.

Thrombolysis and mechanical thrombectomy for arterial disease.

Thrombolytic therapy has been around for close to 30 years now,but its exact role in the treatment of acute and chronic arterial occlusive disease continues to be debated. Studies have produced varying and contradictory results. We are still not sure if thrombolysis has any true advantages over surgical thromboembolectomy,or which lytic agent is the best. Nonetheless, the technique still plays an important role in the treatment of arterial occlusions.

Nerve and conduction tissue injury caused by contact with BioGlue.

BACKGROUND: BioGlue-a surgical adhesive composed of bovine albumin and glutaraldehyde-is commonly used in cardiovascular operations. The objectives of this study were to determine whether BioGlue injures nerves and cardiac conduction tissues, and whether a water-soluble gel barrier protects against such injury. MATERIALS AND METHODS: In 18 pigs, diaphragmatic excursion during direct phrenic nerve stimulation was measured at baseline and at 3 and 30 min after nerve exposure to albumin (n = 3), glutaraldehyde (n = 3), BioGlue (n = 6), or water-soluble gel followed by BioGlue (n = 6). Additionally, BioGlue was applied to the cavoatrial junction overlying the sinoatrial node (SAN), either alone (n = 12) or after application of gel (n = 6). RESULTS: Mean diaphragmatic excursions in the BioGlue and glutaraldehyde groups were lower at 3 min and 30 min than in the albumin group (P < 0.05). Mean excursions in the gel group were similar to those of the albumin group (P = 0.9). Five BioGlue pigs (83%) and one gel pig (17%) had diaphragmatic paralysis by 30 min (P < 0.05 and P = 0.3 versus albumin, respectively). Coagulation necrosis extended into the myocardium at the cavoatrial junction in all 12 BioGlue pigs but only two gel pigs (33%, P < 0.01). Two BioGlue pigs (17%), but no gel pigs, had focal SAN degeneration and persistent bradycardia (P < 0.01). CONCLUSIONS: BioGlue causes acute nerve injury and myocardial necrosis that can lead to SAN damage. A water-soluble gel barrier is protective.

Transcutaneous near-infrared spectroscopy for detection of regional spinal ischemia during intercostal artery ligation: preliminary experimental results.

OBJECTIVE: Real-time information about regional spinal cord ischemia can guide intraoperative management and reduce the risk of paraplegia after thoracic aortic surgery. We hypothesized that near-infrared spectroscopy could provide such information during intercostal and lumbar artery ligation in pigs. METHODS: Transcutaneous near-infrared spectroscopic sensors were placed in the midline over the upper and lower thoracic vertebrae of 4 progressively larger pigs (weight range 21-70 kg). After the entire aorta was exposed, segmental arteries from T6 through L1 were sequentially ligated while regional oxygen saturation was monitored. Decreases in regional oxygen saturation were calculated as percentage changes from baseline. The degrees of ischemia in the upper and lower spinal cord were compared histopathologically. RESULTS: Baseline regional oxygen saturations were similar in the upper (68.8% +/- 9.0%) and lower (68.0% +/- 11.5%, P = .82) cord. After ligation, however, regional oxygen saturation levels were significantly lower in the lower cord (41.3% +/- 10.1%) than in the upper cord (64.8% +/- 9.3%, P = .037). The regional oxygen saturation had decreased by 39.0% +/- 11.5% in the lower cord but only by 6.3% +/- 7.6% in the upper cord (P = .026). This difference was confirmed microscopically: upper-cord sections had fewer ischemic neurons (8.8 +/- 9.4) than did lower-cord sections (21.3 +/- 13.6, P = .002). CONCLUSION: Intraoperative spinal cord ischemia was detectable with near-infrared spectroscopy in pigs weighing as much as 70 kg. The potential utility of this technique in patients undergoing thoracic aortic surgery warrants investigation.

The inaccuracy of simple visual interpretation for measurement of carotid stenosis by arteriography.

PURPOSE: To determine intraobserver and interobserver variability of carotid arteriography interpretation as well as the reliability of simple visual interpretation (SVI) or "eyeballing" of arteriography in the measurement of internal carotid artery stenoses. METHODS: Intraobserver and interobserver measurements of 200 carotid arteriograms were performed in a blinded fashion by two vascular surgeons (VS1 and VS2) using a digital caliber computer program similar to software available in catheterization laboratories. The distal normal internal carotid artery was used as a frame of reference. These computer-derived measurements were compared with previous SVI measurements, found by retrospective chart review, that were performed at the initial time of arteriography. RESULTS: Intraobserver agreement (VS1a vs VS1b and VS2a vs VS2b) within +/-5% using the computer program was 94% and 92%. Interobserver agreement within +/-5% using the computer program for the four possible combinations ranged from 43% to 48%. Interobserver agreement using the computer program increased to 83% to 88% for correct stenosis interpretation within +/-20%. In the 16% to 49% category (by computer measurement), SVI would have placed the stenosis in a higher category 40% to 56% of the time. Likewise, in the 50% to 79% category, comparing SVI with the four different computer caliber measurements, SVI overestimated the stenosis to the 80% to 99% category by 30% to 44%. In the 80% to 99% category, SVI overestimated lesions in 27% to 51% of the cases. All occlusions seen on SVI correlated with computer program measurements. The computer readings in many cases downgraded the degree of carotid stenosis into a lower category and in some cases, may have led to a different treatment paradigm. SVI never underestimated carotid stenosis compared with all matched computer program measurements. CONCLUSIONS: Compared with a method of objective measurement similar to that used in a catheterization laboratory, SVI overestimated most carotid artery stenoses. Given the coming era of carotid stenting and a renewed need for arteriography before carotid intervention, knowledge of variability and correct interpretation of carotid stenosis using available technology remains paramount to warranted treatment.

Emergency surgery for thoracoabdominal aortic aneurysms with acute presentation.

PURPOSE: The mortality rate for elective repair of thoracoabdominal aortic aneurysms is as low as 4% in some surgical centers. However, patients with emergent presentation with acute pain, rupture, or complicated acute dissection traditionally have a poor outcome. We evaluated the results of surgery in a large contemporary series of patients with acute presentation at a tertiary referral center with a special interest and experience in aortic surgery. METHODS: Between 1986 and 1998, 1220 patients underwent repair of thoracoabdominal aortic aneurysms. One hundred twelve patients had acute presentation, and 1108 patients underwent elective repair. Data were collected in a prospectively generated database. RESULTS: Seventy-six patients had rupture, and 36 patients had acute dissection without rupture. The operative mortality rate was 6% for elective cases and 17% for acute cases (P =.0004). The long-term survival was longer for the elective group compared with the acute group (mean, 8.3 +/- 0.4 years versus 5.5 +/- 0.7 years; P <.005). Age did not influence survival rate in the acute group. Postoperative pulmonary complications, paraplegia/paraparesis, and renal impairment occurred in 45%, 14%, and 25%, respectively, of acute cases and were significantly more common than in elective cases (P < or =.01). Left heart bypass was used in 34 acute patients (30%), and intercostal arteries were reattached in 66 acute patients (59%). Surgery without the use of either adjunct was associated with significantly higher mortality and renal impairment rates. CONCLUSION: Repair of thoracoabdominal aortic aneurysms with acute presentation is associated with worse outcome compared with elective cases. Nevertheless, repair may be performed with reasonable mortality and morbidity rates at specialized centers. In the acute setting, the use of surgical adjuncts is associated with improved outcome and should be used when possible. Age does not impact on survival rate in patients with acute presentation, and surgery should not be restricted to only younger patients.

Cerebrospinal fluid drainage reduces paraplegia after thoracoabdominal aortic aneurysm repair: results of a randomized clinical trial.

OBJECTIVE: Despite the use of various strategies for the prevention of spinal cord ischemia, paraplegia and paraparesis continue to occur after thoracoabdominal aortic aneurysm (TAAA) repair. Although cerebrospinal fluid drainage (CSFD) is often used as an adjunct for spinal cord protection, its benefit remains unproven. The purpose of this randomized clinical trial was to evaluate the impact of CSFD on the incidence of spinal cord injury after extensive TAAA repair. METHODS: After randomization, 145 patients underwent extent I or II TAAA repairs with a consistent strategy of moderate heparinization, permissive mild hypothermia, left heart bypass, and reattachment of patent critical intercostal arteries. The repairs were performed with CSFD (n = 76) or without CSFD (n = 69). In the former group, CSFD was initiated during the operation and continued for 48 hours after surgery. The target CSF pressure was 10 mm Hg or less. RESULTS: The two groups had similar risk factors for paraplegia. Aortic clamp time, left heart bypass time, and number of reattached intercostal arteries were also similar in both groups. Thirty-day mortality rates were 5.3% (four patients) and 2.9% (two patients) for CSFD and control groups, respectively (P =.68). Nine patients (13.0%) in the control group had paraplegia or paraparesis develop. In contrast, only two patients in the CSFD group (2.6%) had deficits develop (P =.03). No patients with CSFD had immediate paraplegia. Overall, CSFD resulted in an 80% reduction in the relative risk of postoperative deficits. CONCLUSION: Perioperative CSFD reduces the rate of paraplegia after repair of extent I and II TAAAs.

Characterization and probability of upper extremity deep venous thrombosis.

The objective of this study was to characterize patient demographics, risk factors, and anatomic distribution of upper extremity deep venous thrombosis (UEDVT) to develop a probability model for diagnosis. A retrospective review of all patients who underwent color-flow duplex scanning (CDS) for clinically suspected acute UEDVT over a 5-year period was performed. Patient risk factors and clinical symptoms were evaluated as predictors. Technically adequate complete CDS of 177 upper extremities (UEs) of arms were reviewed. CDS scanning identified acute UE venous thrombosis in 53 (30%) of the arms examined with deep system involvement in 40 (23%). Of the UEs affected, the subclavian was involved in 64%, the axillary in 25%, the internal jugular in 32%, the brachial in 36%, the cephalic in 32%, and the basilic in 47%. Multivariate analysis identified limb tenderness (odds ratio 9.3), history of central venous catheterization (odds ratio 7.0), and malignancy (odds ratio 2.9) as positive predictors for UEDVT. Erythema (odds ratio 0.12) and suspected pulmonary embolism (odds ration 0.06) were identified as negative predictors. A predictive model was designed from these variables. The anatomic distribution of UEDVT obtained from this study is consistent with previous reviews. Potential positive and negative risk factors can be identified from which a predictive model can be designed. Use of this model can help focus clinical suspicion, improve color-flow duplex utilization, and provide timely treatment with anticoagulation.

Predictors of complications after a prospective evaluation of diagnostic and therapeutic endovascular procedures.

OBJECTIVE: To prospectively evaluate complications after diagnostic and therapeutic endovascular procedures (DTEPs) and determine what factors are predictive. METHODS: From December 2002 to December 2003, all patients undergoing DTEPs performed by university vascular surgeons in a catheterization laboratory were prospectively evaluated. Medical demographics, procedure-related details, and type and severity of complications were recorded at the time of the procedure, during the first 24 hours, and at 2 to 4 weeks. Complications were classified as local vascular (LV), local nonvascular (LNV), systemic remote (SR), and major, minor, and nonsignificant. RESULTS: Three hundred-three DTEPs were performed (54.5% DEPs, 45.5% TEPs). At the time of DTEP, 28 complications occurred in 23 patients: 10 LV (3.3%), 15 LNV (5.0%), and 3 SR (1.0%). At 24 hours, 26 complications occurred in 25 patients: 5 LV (1.7%), 7 LNV (2.3%), and 14 SR (4.7%). At 2 to 4 weeks, 26 complications occurred 25 patients: 5 LV (1.7%), 7 LNV (2.3%), and 14 SR (4.7%). The combined major (7.3%) and minor (4.3%) complication rate attributed to DTEPs was 11.6%. Significant predictors (P < .05) by multivariate analysis included thrombolysis, prior stroke, an additional procedure during the study period, and diabetes mellitus (odds ratios: 9.1, 3.2, 2.7, and 2.4, respectively). CONCLUSION: According to newly applied reporting standards, the prospective evaluation of DTEPs reveals that complications are uniformly distributed by type and follow-up period. Just over 1 in 10 patients will suffer either a major or minor complication. Potential predictors have been identified that may assist in patient selection and treatment plans to lower complications resulting from DTEPs.

Pancreatitis caused by rheolytic thrombolysis: an unexpected complication.

Two patients developed acute pancreatitis after mechanical thrombolysis with use of the AngioJet system. Patient 1 had undergone a remote complex revascularization of the lower extremities and presented with acute ischemia after thrombosis of his composite distal bypass. Patient 2 presented with superior vena cava (SVC) syndrome and had thrombosis of the SVC and innominate veins. Despite dissimilar presentations, both patients had renal insufficiency, were treated with mechanical and chemical thrombolysis, and had extensive thrombus burden. The pathophysiology of acute pancreatitis in this setting is believed to be secondary to massive hemolysis in the presence of chronic renal insufficiency. This phenomenon should be considered in patients whom develop abdominal pain after mechanical thrombolysis.

Use of near-infrared spectroscopy to monitor regional cerebral oxygen saturation during infrarenal aortic crossclamping in piglets.

PURPOSE: The hemodynamic changes induced by infrarenal aortic crossclamping have been well documented, but the effects of such crossclamping on cerebral perfusion are unknown. To investigate these effects, we used near-infrared spectroscopy (NIRS) to monitor regional cerebral oxygen saturation (rSO2) during infrarenal aortic crossclamping in a piglet model. METHODS: The study involved 19 piglets, each weighing 7.8 +/- 1 kg. The NIRS sensor was placed on each animal's forehead. General anesthesia was induced, and the infrarenal abdominal aorta was mobilized through a laparotomy. After heparin (1 mg/kg) was administered, crossclamps were applied proximally and distally. A 2 mm segment was resected from the proximal aortic stump, and an aorto-aortic anastomosis was performed. RESULTS: Crossclamping lasted for 30.6 +/- 6.7 min. Between the time of baseline measurement and clamp application, the rSO2 did not decrease significantly (65.4%+/- 8.9% vs. 62.4%+/- 7.8%). However, significant decreases in the rSO2 occurred between baseline measurement and clamp removal (65.4%+/- 8.9% vs. 55.7%+/- 8.9%; P<0.01), between baseline measurement and the end of surgery (65.4%+/- 8.9% vs. 57.7%+/- 7.5%; P<0.01), and between clamp application and removal (62.4%+/- 7.8% vs. 55.7%+/- 8.9%; P<0.01). At these same intervals, no intergroup differences occurred in the temperature, heart rate, or mean arterial pressure. CONCLUSION: Infrarenal aortic crossclamping significantly decreases the rSO2. NIRS, which has the advantages of being non-invasive and continuous, may be useful for monitoring this variable intraoperatively.