Tibial bypass using complex autologous conduit: patency and limb salvage.

Over an 8-year period, we performed 93 lower extremity bypasses using complex autologous conduits, which included (1) contralateral greater saphenous vein (GSV), (2) composite GSV, (3) superficial femoral vein, (4) lesser saphenous vein, (5) cephalic or basilic veins, and (6) composite-sequential (PTFE and vein) grafts. These grafts represented 16% of all infrainguinal bypasses during this period, and all grafts were performed to treat limb-threatening ischemia. Survival, patency, and limb salvage were examined by the life-table method. Primary graft patency was 46 and 38% at 3 and 5 years. Assisted-primary patency was 62 and 59%, and secondary graft patency rates were 68 and 64% at 3 and 5 years. Twenty-nine bypasses (31%) required revision to restore or maintain patency. The 3-year limb salvage rate was significantly better when revision was performed for graft stenosis than for graft thrombosis (90% vs. 46%, p < 0.05). Overall limb salvage rate was 73% at 5 years. The mortality rate was 5.4% and the 5-year survival was 51%. Complex autologous tibial bypasses provided acceptable long-term limb salvage in patients with severe ischemia and inadequate ipsilateral GSV. The increased operating time and complexity required did not produce prohibitive operative risks. Postoperative graft surveillance in these complex vein bypasses allowed revision in many cases before graft occlusion occurred and significantly improved long-term limb salvage.

Arterial reconstruction with deep leg veins for the treatment of mycotic aneurysms.

PURPOSE: Mycotic pseudoaneurysms (MPA) remain challenging clinical problems. Primary surgical management includes control of hemorrhage and debridement of the infected arterial wall. Because critical ischemia may develop after arterial resection, revascularization has been a secondary goal of treatment. Standard anatomic graft placement or prosthetic bypass grafting has been compromised by a high rate of recurrent infection. Extra-anatomic reconstruction is preferred, with the basic goals being threefold: (1) the use of autogenous graft material to reduce the risk of reinfection; (2) the avoidance of significant size mismatches; and (3) graft placement that is anatomically inaccessible, because drug abuse causes many of these lesions. This study reviews a recent series of MPAs applying these treatment goals. METHODS: In a 2-year period, the superficial femoral and proximal popliteal veins were used in the repair of eight MPAs of the common femoral (5), common iliac (1), and brachial (1) arteries, and the infrarenal aorta (1). Most patients (5 of 7) were known intravenous drug users, who had a painful pulsatile mass in an injection area. Two patients had systemic sepsis, one patient with an infected common iliac pseudoaneurysm and one patient with an MPA of the infrarenal aorta. The diagnosis of MPA was made by means of duplex/computed tomography scanning and confirmed by means of arteriography in all cases. RESULTS: Obturator bypass grafting was performed by using a reversed deep leg vein in the five femoral MPAs. An ilioiliac, cross-pelvic bypass grafting procedure with a deep vein was used to repair an MPA of the common iliac artery. A deep vein was also used as a "pantaloon" aortobiiliac graft and for a brachial artery repair. Staphylococcus aureus was revealed by means of cultures in nearly all cases. Distal arterial perfusion was normal after reconstruction. Patients had no significant postoperative leg swelling. No new venous thrombosis below the level of deep vein harvest was revealed by means of duplex scanning. There were no septic complications. CONCLUSION: The superficial femoral/popliteal veins may be particularly useful for limb revascularization in patients with MPAs. This autogenous conduit provides an excellent size-match and a suitable length for reconstruction, because peripheral, axial arteries are generally affected. No clinically significant limb morbidity was related to deep vein removal. Late follow-up is challenging in such cases, but will be required to accurately determine the durability of this strategy.

Duplex ultrasound insertion of inferior vena cava filters in multitrauma patients.

BACKGROUND: Techniques for placement of inferior vena cava (IVC) filters have undergone continued evolution from open surgical exposure of the venous insertion site to percutaneous insertion in most cases today. However, the required transport either to an operating room or interventional suite can be complex and potentially hazardous for the multiply injured trauma patient who may require ventilator support, controlled intravenous infusions, or skeletal immobilization. Increased experience with color-flow duplex scanning for routine IVC imaging and portability of ultrasound equipment have suggested the usefulness of duplex-guided IVC filter insertion (DGFI) in critically ill trauma and intensive care unit (ICU) patients. METHODS: A total of 25 multitrauma/ICU patients were considered for DGIF. Screening color-flow duplex scans were performed on all patients, and obesity or bowel gas prevented ultrasound imaging in 2 cases, leaving 23 patients suitable for DGFI. In each case, the IVC was imaged in the transverse and longitudinal planes. The right renal artery was identified as it passed posterior to the IVC and was used as a landmark of the infrarenal segment of the IVC. All procedures were performed at the bedside in a monitored ICU setting using percutaneous placement of titanium Greenfield filters. Duplex scanning after insertion was used to document proper placement, and circumferential engagement of the filter struts in the IVC wall. An abdominal radiograph was also obtained in each case to confirm proper filter location. Duplex ultrasound imaging was repeated within 1 week of insertion to assess IVC and insertion site patency. RESULTS: DGFI was successful in all cases. The filter was deployed at a suprarenal level in one case, as was recognized at the time of postprocedural scanning. Three patients died as a result of their injuries but there were no pulmonary embolism deaths. Repeat duplex scanning was obtained in 17 patients, and revealed no case of IVC or insertion site thrombosis. CONCLUSIONS: Vena caval interruption can be safely performed under ultrasound guidance in a monitored, ICU environment. In selected multiply injured trauma patients, this will reduce the risk, complexity and cost of transport for these critically ill patients. DGFI also reduces procedural costs compared with an operating room or interventional suite, and eliminates intravenous contrast exposure. Preprocedural scanning is essential to identify patients suitable for DGFI, and careful attention must be paid to the known ultrasonographic anatomical landmarks.

Assessment of ocular perfusion after carotid endarterectomy with color-flow duplex scanning.

PURPOSE: The purpose of this study was to assess the effect of carotid endarterectomy (CEA) on ocular perfusion with the measurement of the ophthalmic artery (OA) and the central retinal artery (CRA) flow velocities with color-flow ocular duplex scanning (ODS). Ocular hemodynamics also were examined in a subset of patients with visual symptoms in an attempt to characterize the origin of the ocular symptoms and their response to surgery. METHODS: Twenty-five patients with internal carotid artery stenoses (>/=70%) underwent 29 CEAs. All the patients underwent ODS for the measurement of the peak systolic velocity (PSV) in the OA and the CRA of the ipsilateral eye before and after CEA. The preoperative and postoperative flow velocities were compared in all the patients and in the patients with and without visual symptoms. RESULTS: The preoperative PSV in the OA was 21.6 +/- 2.2 cm/s and in the CRA was 7.7 +/- 0.7 cm/s. These values were reduced as compared with normative values (OA, 37.8 cm/s; CRA, 10.7 cm/s). After CEA, the PSV increased significantly in both vessels (postoperative OA, 38.6 +/- 2.5 cm/s, P <.0001; postoperative CRA, 12.1 +/- 0.9 cm/s, P =.0008). Fifteen of the 29 CEAs were performed for visual symptoms. The patients with ocular symptoms had significantly lower preoperative PSVs in the CRA as compared with those patients without visual symptoms (CRA with ocular symptoms, 6.5 +/- 0.8 cm/s; CRA with no ocular symptoms, 9.4 +/- 0.9 cm/s; P =.02). The PSV in the OA was not significantly lower in the patients with ocular symptoms. Eight patients (28%) were found to have reversed OA flow before surgery, but only three patients had ocular symptoms. All eight patients had normal antegrade flow in the OA after surgery. CONCLUSION: Severe carotid stenosis may be associated with reduced ocular perfusion, which can be quantitatively evaluated with ODS. Reduced OA and CRA flow velocities are corrected with successful CEA. The patients with ocular symptoms were observed to have significant reductions in CRA flow velocities. Reversed flow in the OA was not a marker for ocular symptoms in this study. ODS can identify global ocular ischemia and may be helpful in the evaluation of patients with atypical visual symptoms or with amaurosis fugax and no evidence of retinal emboli.

Can intrarenal duplex waveform analysis predict successful renal artery revascularization?

PURPOSE: No currently available noninvasive test can preoperatively predict a successful outcome to renal revascularization. Resistance measurements from the renal parenchyma obtained with duplex sonography reflect the magnitude of intraparenchymal disease, and patients with extensive intrarenal disease may respond less favorably to revascularization. To address this question, we reviewed our (primarily) operative experience in patients undergoing renal artery revascularization, and compared the blood pressure (BP) and renal function response with resistance measurements obtained from the kidney both before and after revascularization. METHODS: During a 56-month period, 31 consecutive renal artery revascularizations (25 surgical and 6 percutaneous angioplasties) were performed in 23 patients (21 atherosclerotic, 2 fibromuscular dysplasia). Duplex sonography was performed in each patient before and after revascularization, and parenchymal diastolic/systolic (d/s) ratios were calculated. BP and renal function response to intervention were compared with measurements of intrarenal flow patterns before and after revascularization. RESULTS: Mean parenchymal peak systolic velocity was significantly higher after repair in all patients (pre-repair: 19.5 +/- 1.3, postrepair: 27.2 +/- 1.7; P < .0001). Despite this, there were no statistical differences between preoperative and postoperative parenchymal d/s ratios. A favorable (cured or improved) BP response was seen in 81% (17 of 21) of revascularizations performed for hypertension. Among these successes, parenchymal d/s ratios were in the normal range (ie, > or = 0.30) both before and after repair (mean prerepair: 0.34 +/- 0.03, mean postrepair: 0.31 +/- 0.03; not significant). In 4 patients in which BP failed to improve after intervention, the d/s ratio was abnormal before surgery (< 0.3), and remained so after revascularization (mean preoperative d/s ratio: 0.18 +/- 0.04, mean postoperative d/s ratio: 0.11 +/- 0.04; P = .003). Mean preoperative parenchymal d/s ratios were significantly higher in all patients with a successful BP response when compared with failures (P = .048). Similarly, among patients with single artery repairs, mean preoperative d/s ratios approached significance in successes vs. failures (success: 0.40 +/- 0.03, failure: 0.21 +/- 0.03; P = .054). A decrease in serum creatinine greater than or equal to 20% was seen in 8 of 18 patients (44%) with ischemic nephropathy. These patients also had normal d/s ratios preoperatively (mean 0.39 +/- 0.04), whereas the 10 patients who failed to improve had significantly lower ratios (mean 0.24 +/- 0.03; P = .041). Kidney length did not correlate with d/s ratio. CONCLUSION: Although we do not believe that duplex sonographic measurement of intrarenal flow patterns alone is an accurate means of assessing main renal artery occlusive disease, the resistive indices seem to reflect the magnitude of intraparenchymal disease, and thus may provide important prognostic information for patients undergoing surgical revascularization. Our data suggest that a preoperative d/s ratio below 0.3 correlates with clinical failure relative to BP and renal function responses.

Nitric oxide synthase inhibition negates septic-induced alterations in cytoplasmic calcium homeostasis and membrane dynamics.

This study was undertaken to evaluate the role of nitric oxide (NO) in the sepsis-induced disruption of intracellular calcium homeostasis and membrane dynamics. Anticoagulated whole blood was obtained from 10 healthy volunteers. Equal aliquots were incubated with saline (control), 2 microg/mL Escherichia coli endotoxin (lipopolysaccharide), 8 microg/mL NO inhibitor, N-monomethyl arginine (NMA), and endotoxin plus NO inhibitor (lipopolysaccharide/NMA). Erythrocytes were harvested, washed, and loaded with the calcium chelator, FURA-2AM, and the fluorescent membrane probe TMA-DPH. Cells were evaluated for both intracellular calcium concentration and membrane viscosity (anisotropy) by fluorescent spectrophotometry. Endotoxin induced a significant increase in both intracellular calcium concentration and anisotropy. NMA had no intrinsic affect on either of these cellular characteristics. NMA was, however, effective in preventing the endotoxin-induced changes. These results suggest that NO may play a role in the disruption of intracellular calcium homeostasis and erythrocyte membrane deformability noted in sepsis.