Patterns and outcomes of aortofemoral bypass grafting in the era of endovascular interventions.

OBJECTIVES: The aim of the study is to study contemporary presentation patterns and clinical results in patients undergoing aortofemoral bypass (AFB) surgery. DESIGN: This was a retrospective comparative study. MATERIAL AND METHODS: During a 14-year period, 269 consecutive patients (mean age 65 years) underwent AFB. Indications included occlusive disease with severe intermittent claudication (IC) (n = 86), critical limb ischaemia (CLI, n = 97) and aneurysmo-occlusive disease (n = 86). RESULTS: From 2000-07 on, AFB was performed more frequently for occlusive disease with CLI than for other indications (48% vs. 31% before 2000, P = 0.009) and also in women (51% vs. 32% before 2000, P = 0.003), compared to the period before 2000. Thirty-day mortality was reduced during 2000-2007 to 2.4%, compared with 4.3% during 1993-1999, although this difference was not statistically significant (P = 0.73). Morbidity did not change substantially over the study period. Predictors of 30-day mortality included indication (CLI = 4.1% vs. claudication = 1.2% (P = 0.37)) and chronic kidney disease (CKD, serum creatinine > 1.5 mg dl⁻¹) (11.1% vs. 2.9% in normal renal function, P = 0.07), the latter being the single predictor on multivariate analysis (hazard risk 4.2, P = 0.047). Overall 5 and 10-year assisted primary and secondary patency was 95% and 88%, and 99% and 95%, respectively. Survival at 5 and 10 years was 69% and 48%, respectively. Patient age (hazard risk 1.05, P < 0.001), CKD (hazard risk 1.79, P = 0.018) and diabetes (hazard risk 1.56, P = 0.022) were independent predictors of worse long-term survival. Long-term outcome did not change over the course of the study. CONCLUSIONS: In the contemporary era, AFB is more likely to be performed for CLI and in women than in the past. Despite these changes, perioperative mortality and morbidity remain low and long-term outcome excellent.

Factors affecting outcome in proximal abdominal aortic aneurysm repair.

Sixty-five consecutive patients undergoing nonemergent repair of an abdominal aortic aneurysm (AAA) originating above the visceral and/or renal arteries were studied to determine operative results and identify factors influencing outcome of proximal AAA repair. Factors associated with postoperative morbidity were analyzed using multivariate analysis. There were no postoperative deaths, paraplegia/paraparesis, or symptomatic visceral ischemia. Proximal AAA repair can be accomplished with acceptable mortality. If renal artery bypass or reimplantation is anticipated, cold renal perfusion may protect against renal dysfunction. Postoperative pulmonary dysfunction can be reduced by avoiding radial division of the diaphragm.

Role of neuropeptide Y in the development of two-kidney, one-clip renovascular hypertension in the rat.

OBJECTIVE: Along with the renin-angiotensin system, sympathetic stimulation may contribute to renovascular hypertension. The vasoactive peptide neuropeptide Y (NPY) is co-released with and potentiates the pressor effects of norepinephrine through the Y-1 receptor. NPY, by exaggerating sympathetic activity, may contribute to renovascular hypertension, possibly by augmenting adrenergic-mediated renin release. This was studied by determining the effect of continuous Y-1 blockade on the development of two-kidney, one-clip renovascular hypertension and the effect of NPY on in vitro renin release. METHODS: Mean arterial pressure and renal blood flow responses to NPY (10 microg/kg, administered intravenously) were measured in five anesthetized Sprague-Dawley rats before and after BIBO3304TF administration to test the Y-1 antagonist BIBO3304TF. In hypertension studies, 28 rats underwent left renal artery clipping. Of these, 13 were implanted with a mini-osmotic pump for continuous BIBO3304TF infusion (0.3 microg/h, administered intravenously); the other 15 underwent sham implantation. Systolic blood pressure was then monitored for 4 weeks. Finally, in vitro renin release was measured from renal cortical slices (n = 6-12) incubated with NPY (10(-8) to 10(-6) mol/L) or NPY plus the adrenergic agonist isoproterenol (10(-4) mol/L). RESULTS: BIBO3304TF attenuated the NPY-induced increase in mean arterial pressure by 54% (P <.02) and the NPY-induced decrease in renal blood flow by 38% (P <.05). In 4-week hypertension studies, systolic blood pressure in clipped controls increased from 130 +/- 3 mm Hg to 167 +/- 6 mm Hg (P <.01), whereas BIBO3304TF-treated rats had no significant increase (125 +/- 3 mm Hg to 141 +/- 8 mm Hg). Final systolic blood pressure was 26 mm Hg lower in BIBO3304TF-treated rats than in controls (P <.01). In renal cortical slices, no NPY effect was observed in basal or isoproterenol-stimulated renin release. CONCLUSIONS: The Y-1 receptor antagonist BIBO3304TF attenuated acute pressor responses to NPY and blunted the development of two-kidney, one-clip renovascular hypertension in rats. NPY may contribute to the hypertensive response in this renovascular hypertension model. Our in vitro data do not suggest that this is due to NPY enhancement of renin release.

Visceral pseudoaneurysms due to pancreatic pseudocysts: rare but lethal complications of pancreatitis.

OBJECTIVE: Erosion of pancreatic pseudocysts into adjacent vessels is a rare but highly lethal cause of intra-abdominal hemorrhage. Percutaneous angiographic embolization (PAE) of the bleeding artery has recently been advocated as the preferred therapy. This study was undertaken to survey the outcome after treatment of this complication and to make recommendations for its management. METHODS: An 11-year retrospective analysis was performed of all patients treated at a large tertiary care referral center for visceral artery pseudoaneurysms associated with pancreatic pseudocysts. RESULTS: From 1988 to 1998, 256 patients were admitted for complications of pancreatic pseudocysts. Sixteen patients (11 men and 5 women) were identified in whom a pseudocyst had eroded into a major blood vessel with hemorrhage or development of a false aneurysm. The mean age was 45 years (range, 23-67 years). Active bleeding was present in 13 patients, whereas three had evidence of recent hemorrhage. Ten of 16 patients initially underwent operative therapy, four elective and six emergency, whereas six stable patients were initially treated with PAE. Technical failures of the initial treatment or secondary complications required both therapeutic modalities in six patients, which resulted in 13 total surgical interventions and 10 PAEs. The surgical morbidity rate was 62% (8 of 13), whereas that of PAE was 50% (5 of 10). Three deaths occurred after emergency operations, two of which failed to stop the bleeding, accounting for all of the deaths in the series (3 [19%] of 16). A trend was noted toward increased death with necrotizing pancreatitis (P =.07) and emergency surgery (P =.06). Ranson's criteria were not found to be predictive of death in this series. Surgical drainage procedures were required in seven (44%) of 16 patients for infections (n = 3) or mass effect of the pseudoaneurysm (n = 3). The mean size of pseudoaneurysms that required operative intervention for secondary complications was 13.9 cm, compared with 7.7 cm for all others in the series (P =.046). Long-term follow-up was available in all 13 survivors at a mean of 44 months (range, 1-108 months). CONCLUSIONS: The management of pancreatic pseudocyst-associated pseudoaneurysms remains a challenging problem with high morbidity and death rates. Operation and PAE play complementary management roles. PAE is recommended as the initial therapy for hemodynamically stable patients. Surgery should be reserved for actively bleeding, hemodynamically unstable patients; for failed embolization; and for other secondary complications such as infection or extrinsic compression.

Nontraumatic lower-extremity acute arterial ischemia.

BACKGROUND: The outcome of arterial bypass reconstruction in the setting of acute arterial ischemia has not been well defined. METHODS: This retrospective review consists of 71 consecutive patients (54 with native arterial thrombosis, 17 with graft thrombosis) who underwent an urgent/emergent arterial bypass reconstruction for acute arterial ischemia with threatened limb viability. RESULTS: The 30-day mortality and major amputation rates were 9.9% and 7.1%, respectively. Death, limb loss, or both, were associated with a paralytic limb (P = 0.001) and congestive heart failure (P = 0.03). Overall, 45 of 71 (63%) patients were discharged with limb salvage and ambulatory function. Cumulative graft patency was 77% and 65% at 1 and 2 years, respectively, and closely approximated the 1- and 2-year limb-salvage rates of 76% and 63%, respectively. CONCLUSIONS: Arterial bypass reconstructions appear warranted in acute arterial ischemia, in that a majority of patients retain a functional viable limb. Late graft thrombotic complications limit long-term benefit.

Response to angiotensin inhibition in rats with sustained renovascular hypertension correlates with response to removing renal artery stenosis.

PURPOSE: Sustained (late-phase) renovascular hypertension is associated with lower plasma renin activity than is the early phase. It is not clear to what extent this reduced plasma renin activity reflects diminished influence of the renin-angiotensin system. It also is not clear whether this change in the character of the disease influences the effectiveness of surgical removal of the renal artery stenosis in reversing hypertension. Using an animal model of sustained (> or =10 weeks after renal artery clipping) two-kidney, one-clip renovascular hypertension, we hypothesized that the magnitude of the depressor response to selective angiotensin II receptor blockade with losartan would reflect the influence of the renin-angiotensin system on hypertension and enable us to predict the depressor response to subsequent surgical removal of the clip. METHODS: The left renal arteries of 20 male Sprague-Dawley rats weighing 150 to 200 gm were fitted with a silver clip (0.23 mm internal diameter). Systolic blood pressure was measured by means of tail-cuff plethysmography for 10 weeks. Rats were then given losartan orally (30 mg/kg a day) for 1 week while blood pressure was monitored. After an additional week to allow recovery, 13 rats underwent surgical unclipping, and seven underwent sham repair. Blood pressure again was monitored over the final week. RESULTS: All two-kidney one-clip rats had hypertension 10 weeks after clipping (mean systolic blood pressure 206 +/- 10 mm Hg). Losartan decreased systolic blood pressure by 36 +/- 6 mm Hg. The response was variable, ranging from 3 to 66 mm Hg, and overall blood pressure did not normalize (170 +/- 8 mm Hg). Subsequent surgical unclipping decreased systolic blood pressure by 46 +/- 9 mm Hg. Again the response was variable, ranging from 10 to 99 mm Hg, although overall blood pressure did not normalize (164 +/- 7 mm Hg). The decrease in blood pressure after unclipping showed a high correlation with the blood pressure decrease after losartan administration (r = 0.861, p < 0.001). Resting plasma renin activity (before intervention) was 16 +/- 4 ng angiotensin I per milliliter per hour and was not predictive of the response to either losartan or surgical unclipping. The rats subjected to sham operations had no statistically significant changes in blood pressure. Histologic evaluation showed patent renal arteries without appreciable stenosis or intimal hyperplasia after removal of the clips. CONCLUSIONS: In sustained two-kidney, one-clip renovascular hypertension, the depressor response to angiotensin II receptor blockade is attenuated, suggesting that late-phase hypertension becomes increasingly angiotensin II-independent. In our model, the extent to which sustained renovascular hypertension becomes refractory to 7 days of angiotensin II blockade is highly predictive of the ultimate outcome of surgical repair of renal artery stenosis.

Aortoscopy: a guidance system for endoluminal aortic surgery.

PURPOSE: The aim of this project was to evaluate the feasibility of aortoscopy for guidance of endoluminal aortic procedures and to determine whether aortoscopy has advantages over fluoroscopy in a pig model. METHODS: To establish feasibility aortoscopic guidance was used for making endoluminal aortic measurements, cannulating small arteries for arteriograpy, and placing intraaortic stents and grafts in 11 pigs. To compare aortoscopy and fluoroscopy measurements were made and stents were placed by a surgeon using only aortoscopic guidance in 10 pigs and by an interventional radiologist using only fluoroscopic guidance in 10 pigs. Postmortem dissections were performed to determine measurement and device placement accuracy. RESULTS: In the feasibility study aortoscopic measurements differed from postmortem measurements by a mean distance (+/- SD) of 1.2 +/- 0.2 mm. Stents and grafts were placed a mean of 2.3 +/- 1.9 mm distal to the most inferior renal artery with no stent covering an orifice. All attempts at cannulating spinal arteries greater than 2 mm in diameter were successful. In the comparison of aortoscopic and fluoroscopic guidance, fluoroscopic measurements differed from postmortem measurements by 2.6 +/- 2.4 mm (p = 0.223). Stents placed with aortoscopic guidance were 1.1 +/- 1.3 mm distal to the most inferior renal artery, whereas stents placed with fluoroscopic guidance were 3.4 +/- 2.5 mm distal to the most inferior renal artery (p = 0.019). CONCLUSIONS: These results demonstrate that aortoscopy is a useful guidance system for endoluminal aortic procedures and may have advantages over fluoroscopy alone.

Surgical complications of transaxillary arteriography: a case-control study.

PURPOSE: The purpose of this study was to review the complications of transaxillary arteriography (TRAX), determine clinical factors associated with their occurrence, and define optimal treatment methods. METHODS: A retrospective review of 842 consecutive TRAX studies performed in a large, urban, tertiary care, academic medical center was undertaken. Patients with complications were compared with a concurrent randomized control group without complications with the use of a multivariate analysis model. Results of operative therapy for nerve injury were compared with those of nonoperative therapy. RESULTS: Nineteen (2.3%) complications were identified including 14 nerve injuries, four expanding hematomas/pseudoaneurysms without neurologic deficit, and one puncture site thrombosis. Several statistically significant or suggestive findings associated with the occurrence of complications were identified: female sex (odds ratio [OR] = 4.7), systolic blood pressure > or = 150 mm Hg at the conclusion of TRAX (OR = 9.5), periprocedural systemic heparin anticoagulation (OR = 7.9), concomitant use of intraarterial thrombolysis or percutaneous angioplasty (OR = 12.0), and duration of procedure > or = 90 minutes (OR = 4.0). Patients who underwent prompt exploration (< or = 4 hours from symptom onset) for nerve injuries were more likely to have complete resolution of their neurologic deficits (five of six patients) than those who were observed or underwent delayed operation (three of eight patients) (OR = 8.3). CONCLUSIONS: Aggressive treatment of post-TRAX hypertension, limitation of TRAX duration, delay of postprocedure anticoagulation, and use of alternative sites for arterial puncture in female patients or patients undergoing catheter-based intervention may reduce the incidence of TRAX-related complications. In patients who have neurologic deficits prompt surgical exploration of the puncture site with decompression of the involved nerve(s) may reduce the incidence of prolonged deficits.

An angioscopic method for intraluminal aortic evaluation and stent placement.

PURPOSE: The purpose of this study was to develop an angioscopic technique to visualize the endoluminal surface of the aorta and to guide vascular stent placement. METHODS: A fiberoptic angioscope, fitted with a balloon at its tip, was passed via a carotid arteriotomy into the abdominal aorta of seven anesthetized pigs. Saline solution inflation of the balloon allowed for blood displacement and clear visualization of the endoluminal anatomy. After the left renal artery orifice had been identified with angioscopy, a catheter was inserted via a left femoral sheath to cannulate the orifice under direct visualization. The position of the catheter was verified angiographically. A vascular stent was loaded onto an angioplasty balloon, inserted through a right femoral arteriotomy, positioned by use of angioscopic visualization, and deployed immediately below the left renal artery orifice. RESULTS: The aortic trifurcation and the lumbar and renal artery orifices were clearly visualized in every animal. Vascular stents were placed in seven animals within an average of 3.14 +/- 1.14 mm (mean +/- SEM, range 0 to 8 mm) below the inferior rim of the left renal artery orifice. No stents were positioned above a renal artery orifice or obstructed blood flow. CONCLUSIONS: This angioscopic technique permitted detailed evaluation of aortic endoluminal anatomy and precise implantation of vascular stents. Direct endovascular visualization may facilitate other endovascular procedures, including endovascular grafting.

A comparison of operative approaches and parameters predictive of success in multilevel arterial occlusive disease.

BACKGROUND: The correction of abnormal inflow alone in patients with multilevel arterial occlusive disease (MLAOD) may be inadequate to relieve limb-threatening ischemia. This study was undertaken to compare operative approaches and attempt to define preoperative parameters predictive of limb salvage in patients with MLAOD. STUDY DESIGN: The outcome after revascularization for 194 patients with limb-threatening ischemia MLAOD was assessed retrospectively. One hundred fifty-one patients initially underwent an inflow operation alone. Based on whether or not these patients required an outflow operation within one year, they were divided into two groups: group 1, no outflow operation (121 patients, 121 limbs), and group 2, outflow operation required for continued ischemic symptoms (30 patients, 30 limbs). A separate group of forty-three patients (43 limbs) underwent synchronous inflow-outflow operations, or multilevel revascularization, as their initial operative procedure (group 3). RESULTS: Perioperative complications and mortality rates did not differ between groups. Limb salvage rates were similar for groups 1 and 3, whereas in group 2, limb salvage rates were significantly reduced (p = 0.0184). Long-term limb salvage after an isolated inflow procedure was associated with lack of prior vascular reconstructions (p = 0.0002), the absence of tissue loss (p = 0.0019), and an infrageniculate angiographic runoff score of less than 6 (p = 0.054). CONCLUSIONS: In patients with limb-threatening MLAOD, synchronous inflow-outflow operations can be performed with resultant morbidity and mortality rates comparable with inflow alone. After an inflow operation, the approach of "expectant management" may ultimately compromise limb salvage if a subsequent outflow operation is required.

Outpatient duplex scanning for deep vein thrombosis: parameters predictive of a negative study result.

PURPOSE: Although clinical examination has been reported to be unreliable in the diagnosis of deep vein thrombosis (DVT), this conclusion has often been derived from hospitalized patients (HP) and may not be applicable in an outpatient setting. This study was undertaken to define clinical parameters that might predict the diagnostic value of emergency venous duplex scanning (VDS). METHODS: Venous duplex scans performed over a 9-month period (interval I) in 154 outpatients (154 limbs) and 145 HP (145 limbs) with suspected DVT were reviewed. RESULTS: Eighteen percent of scans of outpatients and 31% of scans of HP were interpreted as positive for lower extremity DVT. With stepwise logistic regression analysis, criteria predictive of a negative result of outpatient VDS included (1) duration of symptoms greater than 7 days (p = 0.003), (2) thigh circumference difference relative to the uninvolved side of less than 3 cm (p = 0.001), and (3) no history of neoplasia (p = 0.03). This model, when applied prospectively to 68 outpatients (68 limbs) over the next 5 months (interval II), yielded a negative predictive value (NPV) of 96.7% (sensitivity 90.9%, specificity 50.9%, positive predictive value 26.3%). Of the 222 outpatients examined during intervals I and II, 98 (44%) met these three clinical criteria. Three of these 98 outpatients had DVT on VDS and thus would have been misclassified as having a negative result. With a similar logistic regression analysis for HP, clinical criteria achieved an NPV of only 75% (sensitivity 36%, specificity 90%, positive predictive value 62%). CONCLUSION: Clinical assessment is unreliable in the diagnostic evaluation of HP with suspected DVT. In an outpatient population, however, clinical evaluation with the above criteria achieved an NPV of 96.7% in the diagnosis of DVT. These parameters may be useful as guidelines in determining the appropriateness of emergency outpatient VDS.

Repair of pararenal abdominal aortic aneurysms. An analysis of operative management.

OBJECTIVE: To analyze different operative approaches for repair of pararenal abdominal aortic aneurysm, to define factors associated with perioperative morbidity, particularly renal insufficiency, and to compare the results of pararenal abdominal aortic aneurysm repair with standard infrarenal repair. DESIGN: Case series review of all patients undergoing repair of nonruptured pararenal abdominal aortic aneurysms over 7 consecutive years at a tertiary care teaching hospital. PATIENTS: Fifty-three consecutive patients with nonruptured atherosclerotic pararenal abdominal aortic aneurysms undergoing operative repair. A comparison group of 65 patients randomly selected from a pool of 384 patients undergoing concurrent infrarenal abdominal aortic aneurysm repair. MAIN OUTCOME MEASURES: Operative morbidity and mortality, postoperative renal insufficiency, estimated blood loss, perioperative blood and fluid requirements, and length of hospital stay. RESULTS: Postoperative renal insufficiency was more likely when concomitant renal revascularization was performed (P = .007) or when any major intraoperative complication occurred (P = .008). Retroperitoneal abdominal aortic aneurysm repair was associated with lower estimated blood loss (P = .05) and less fluid requirement within the first 24 hours following operation than transperitoneal repair (P = .03). No differences in outcome measures were identified with regard to site of proximal aortic clamping (supraceliac vs suprarenal). Pararenal abdominal aortic aneurysms were larger and their repair was associated with greater estimated blood loss (P = .007), intraoperative blood replacement (P < .001), and a longer hospital stay (P = .02) than infrarenal abdominal aortic aneurysms. CONCLUSIONS: Pararenal abdominal aortic aneurysm repair is a technically challenging operation associated with significant morbidity. A retroperitoneal approach facilitates repair. The site of proximal aortic cross-clamping should be dictated by technical factors and not by any perceived outcome advantages.

Supraceliac aortic cross-clamping: determinants of outcome in elective abdominal aortic reconstruction.

PURPOSE: A 7-year experience in which 43 patients underwent supraceliac aortic cross-clamping (SC-AXC) during elective abdominal aortic reconstruction was reviewed. METHODS: Operation was performed for abdominal aortic aneurysm (AAA) in 29 (68%) patients, aortoiliac occlusive disease in seven (16%), proximal anastomotic AAA in three (7%), "shaggy" aorta syndrome in three (7%), and in situ grafting of a previously ligated aorta in one (2%) patient. The indications for supraceliac control included pararenal AAA origin (25), pararenal aortic atherosclerosis (18), inflammatory AAA (2), and a short infrarenal aortic stump (1). Vital organ ischemic complications (VOICs) were defined as any major ischemic complication involving the liver, kidneys, bowel, or spinal cord. RESULTS: The incidence of VOICs was significantly increased when concomitant renal or visceral revascularization (CRVR) was required (p = 0.002) and correlated with an increasing SC-AXC time (p = 0.015). In patients undergoing CRVR (n = 16) the perioperative mortality rate was 25%; VOICs developed in six patients and included renal failure (3), mesenteric/colonic ischemia (3), hepatic ischemia with coagulopathy (2), and spinal cord ischemia (1). In contrast, in those not requiring CRVR (n = 27), SC-AXC was well tolerated. There were no VOICs and no deaths; morbidity rate was 33%. CONCLUSIONS: The incidence of VOICs associated with the use of SC-AXC is primarily related to the level of preoperative renal or mesenteric insufficiency, the severity of pararenal aortic atherosclerosis, the extent of the operative procedure, and the duration of proximal aortic cross-clamping. In complex abdominal aortic reconstruction in which infrarenal aortic control is either not possible or deemed hazardous, SC-AXC is a safe and valuable technique for achieving proximal control.

Long-term results of venous reconstruction after vascular trauma in civilian practice.

The natural history of venous reconstruction (VR) in terms of patency and clinical outcome after vascular trauma has not been well documented. This study consists of 32 patients who had VR performed for extremity vascular trauma and were available for long-term assessment (mean follow-up time 49 months, range 6 to 108 months). The types of repair performed were as follows: lateral venorrhaphy (simple repair) (56%), interposition grafting (22%), patch repair (12.5%), and end-to-end repair (9.5%). Seventeen patients underwent venography after the operation with documentation of repair patency in eight patients (46%) and thrombosis in nine (54%). Only two patients had significant clinical edema at follow-up examination. Noninvasive venous evaluation consisted of Doppler ultrasonography, impedance plethysmography, photoplethysmography, and color-flow duplex scanning (CFDS). The photoplethysmography-derived venous refilling time of the injured extremity was 34.9 +/- 16.2 seconds whereas that of the contralateral noninjured extremity was 36.8 +/- 16.1 seconds (p = 0.5). Based on standard criteria for CFDS, 90% of VRs were patent. Eight repairs that were patent in the early postoperative period remained patent on CFDS. Of the nine repairs with early thrombosis, eight were assessed as patent on follow-up CFDS. In conclusion, VR is a durable surgical procedure associated with minimal morbidity, good long-term patency, and preservation of venous competence. The natural history of thrombosed VRs appears to be one of thrombus absorption with recanalization.