Brain edema after carotid surgery.

The postoperative hyperperfusion syndrome describes an abrupt increase in blood flow with loss of autoregulation in surgically reperfused brain. Reports described a spectrum of findings, including severe headache, transient ischemia, seizures, and intracerebral hemorrhage. Hypertension is common after carotid artery surgery and often plays a role in the pathophysiology. We now report five patients with severe white matter edema after carotid surgery, a finding not previously included in the hyperperfusion syndrome. Five to 8 days after carotid surgery and after hospital discharge, each patient developed hypertension, headache, hemiparesis, seizures, and aphasia or neglect due to severe white matter edema ipsilateral to the carotid surgery. One patient had a small hemorrhage within the edematous area. Hypertension was severe in four patients and moderate in one. The carotid artery was patent by ultrasound or angiography in each patient after surgery. Transcranial Doppler showed increased velocities ipsilateral to surgery in two patients and bilaterally in one. Computed tomographic abnormalities and neurologic signs resolved within 3 weeks in four of the five patients treated with antihypertensives and anticonvulsants. The fifth patient died from herniation secondary to massive edema. Brain edema with focal neurologic signs should be included as a serious but potentially reversible component of the postoperative hyperperfusion syndrome.

Treatment of calcific aortic stenosis by balloon valvuloplasty.

Recent reports have established the feasibility of using balloon valvuloplasty to reduce left ventricular outflow tract obstruction due to a calcified aortic valve. The present study summarizes experiences with this technique in 9 patients (7 women, 2 men, mean age 78 years) in whom balloon valvuloplasty was used to treat calcific aortic stenosis. Peak aortic valve gradient (mm Hg) decreased from 68 +/- 8 (mean +/- standard error of the mean) before valvuloplasty to 35 +/- 5 after valvuloplasty (p = 0.003). Mean aortic valve gradient decreased from 57 +/- 7 before valvuloplasty to 30 +/- 5 after valvuloplasty (p = 0.006). Calculated aortic valve area increased from 0.42 +/- 0.04 to 0.81 +/- 0.06 cm2 (p = 0.005). Balloon valvuloplasty failed to diminish aortic valve obstruction in only 1 patient who, at subsequent surgery, had a congenitally bicuspid aortic valve. Significant aortic regurgitation was not observed in any of the 9 patients after valvuloplasty. One patient did have a highly focal, presumably embolic, brain stem infarct during the procedure. Femoral arterial blood loss, related to wire-guided exchange of balloon catheters too large for a 12Fr introducer sheath, was minimized by direct arterial exposure in 8 of the 9 patients. Thus, these findings confirm the efficacy of balloon valvuloplasty for the treatment of calcific aortic stenosis. The procedure, however, is not without hazard.

The costs of surgery for limb-threatening ischemia.

The clinical courses of 106 patients with limb-threatening ischemia were traced for as long as 5 years to determine the cost of their care. Seventy-eight patients initially treated with vascular reconstruction accrued an average of $40,769 +/- $3726 in costs over a mean follow-up period of 805 +/- 57 days, during which they had an average of 2.4 +/- 0.2 hospitalizations or 67 +/- 6 inpatient days. Twenty-eight high-risk patients treated with primary amputation accrued $40,563 +/- $4729 in costs over a mean follow-up period of 663 +/- 97 days, during which they had an average of 2.2 +/- 0.3 hospitalizations or 85 +/- 10 inpatient days. Successful revascularization resulted in lower costs ($28,374) than did primary amputation ($40,563) or failed reconstruction ($56,809). Patients with ischemic tissue loss accrued costs more rapidly than did patients with rest pain only. The high cost of providing care for these patients and the advent of diagnosis related group reimbursement mandate that proposed treatment protocols be evaluated not only for their effectiveness but also for their cost-effectiveness.

Endothelial cell seeding of small-caliber synthetic grafts in the baboon.

Endothelial cell (EC) seeding has been proposed as a method to improve the performance of small-caliber synthetic vascular prostheses. Seeding experiments to date have all been carried out in the dog. This study investigates EC seeding of small-caliber Dacron carotid interposition grafts compared with contralateral control grafts in the baboon. Surface thrombogenicity was assessed at 24 hours, 2 weeks, and 4 weeks after implantation with indium 111-labeled autologous platelets. Morphologic and immunohistochemical techniques were used to assess the identity and homogeneity of the EC inoculum before seeding and to identify cell types on the harvested grafts. There was no significant difference in patency rates between seeded and control grafts at 5 weeks. Platelet accumulation on seeded grafts was significantly less (p less than 0.05) than on paired controls at 2 and 4 weeks after implantation. The luminal lining of seeded grafts had more cellular ingrowth, less adherent thrombus, and more surface cells with the morphologic and histochemical characteristics of EC than did the lining of controls. EC seeding reduces the platelet reactivity and accelerates EC coverage of small-caliber grafts in the baboon.

Clinical, hemodynamic, and anatomic follow-up of direct venous reconstruction.

Conventional therapy for the advanced clinical stages of the postthrombotic syndrome is associated with recurrence of symptoms and ulcer. Direct venous reconstruction may relieve the symptoms of patients with either iliac vein obstruction or valvular incompetence, but there are few reports detailing late hemodynamic and anatomic findings. We summarized the clinical, hemodynamic, and anatomic follow-up of six patients with saphenofemoral bypass (SFB) and ten patients with axillary vein valve-to-popliteal vein transplants (PVTs) who were followed up for a minimum of two years. All ten ulcers in the PVT group healed and symptoms of venous claudication, limb swelling, and all ulcers healed in the SFB group. Late (greater than 2 years) anatomic and functional assessment showed that the SFB bypasses were patent and the PVTs were both patent and functional.

The effect of suprarenal cross-clamping on abdominal aortic aneurysm repair.

Two hundred five patients who underwent elective abdominal aortic aneurysm repair were divided into two groups: those who underwent infrarenal cross-clamping alone (n = 166) and those who underwent suprarenal cross-clamping alone or combined with infrarenal cross-clamping (n = 39). Mortality was comparable between groups (1.2% for infrarenal cross-clamping vs 2.6% for suprarenal cross-clamping). Transient renal insufficiency was more frequent in the suprarenal group than in the infrarenal group (28% vs 10%), but dialysis rates (3% for suprarenal vs 2% for infrarenal) were similar. Cardiac morbidity was comparable between groups as well. Operating room data reflected the technical challenge of complex aneurysm repairs. The retroperitoneal approach was the preferred exposure in the suprarenal group since better access to the suprarenal aorta may be achieved with this technique. While abdominal aortic aneurysm repairs requiring suprarenal cross-clamping remain a technical challenge, the risks are not formidable and suprarenal cross-clamping should be considered when confronted with difficult periaortic dissection.

The management of early in situ saphenous vein bypass occlusions.

To determine the causes and optimum management of early in situ bypass occlusions, we reviewed our experience of 13 thromboses occurring within the first 30 postoperative days in 148 in situ saphenous vein reconstructions. All early thrombosed bypasses were performed for limb salvage, with 31% of bypasses to the popliteal level and 69% to infrapopliteal vessels. The median time to occlusion was 24 hours. All patients underwent reoperation. Graft failure was due to retained venous valves in 31% of the procedures, other technical problems in 38%, and inadequate outflow in 31%. Reoperative surgery was individualized. In grafts explored for thrombosis, the one-year graft patency rate was 46%, and the limb salvage rate was 54%. Graft patency did not appear to correlate with the presumed cause of initial graft occlusion. Our results indicate that an aggressive surgical approach is appropriate in early in situ graft thrombosis.

Correlation of B-mode ultrasound imaging and arteriography with pathologic findings at carotid endarterectomy.

Presently most noninvasive methods for assessing extracranial carotid disease have relied on hemodynamic change associated with significant stenosis. Recent evidence has suggested that both ulceration and/or plaque hemorrhage may frequently play an important role in the pathophysiology of carotid disease. To assess the ability of B-mode ultrasound to provide this anatomic information, in a prospective blinded manner we compared B-mode ultrasound and selective four-vessel arteriography to pathologic specimens obtained at the time of 89 carotid endarterectomies. The presence of ulceration, plaque characteristics (particularly hemorrhage), and luminal diameter were described for each modality. While arteriography detected only 16 of 27 ulcerations (sensitivity, 59%), B-mode ultrasound had a greater sensitivity (24/27, 89%). Both modalities had comparable specificities (arteriography, 73%; B-mode ultrasound, 87%). Moreover, B-mode ultrasound was highly sensitive for demonstrating plaque hemorrhage (27/29, 93%), as well as being quite specific (84%). Assessment of luminal reduction by B-mode ultrasound improved with technologist/interpreter experience and was significantly improved by adding real-time spectral analysis. Because of B-mode ultrasound's sensitivity for imaging ulceration and plaque hemorrhage, it offers significant advantages for the noninvasive detection of extracranial carotid disease.

Retroperitoneal approach to high-risk abdominal aortic aneurysms.

During a 14-month period we used a left-flank, retroperitoneal, retrorenal approach in 23 high-risk patients with abdominal aortic aneurysm (AAA). Fourteen patients underwent suprarenal/celiac cross clamp for juxtarenal/suprarenal AAA and/or associated occlusive disease. Other indications for this approach included diminished cardiac and/or pulmonary reserve, previous extensive abdominal surgery, obesity, and inflammatory AAA. There was only one death (4%) in this high-risk group and minimal operative morbidity. The flexibility afforded by this approach for high aortic exposure allowed expeditious proximal anastomoses with minimal postoperative renal dysfunction. Pulmonary complications, ileus, and pain were reduced and patient mobilization was rapid despite the complex nature of the operative procedures. We believe that this approach offers significant advantages for all cases of AAA but particularly for anatomically complex lesions and medically high-risk patients.

Antiplatelet therapy and vascular grafts. Studies in a baboon ex vivo shunt.

Antiplatelet therapy is currently recommended in an effort to improve patency rates of small-caliber vascular grafts. The effect of aspirin and heparin on acute platelet deposition was studied in a baboon ex vivo shunt. Two grafts, expanded polytetrafluoroethylene and knitted Dacron, were exposed to a flow rate of 25 mL/min after administration of aspirin or heparin. Indium 111-labeled platelet uptake by the grafts was determined over 2 1/2 hours. The amount of platelet deposition in the treated groups was significantly less than that of controls after 2 1/2 hours. There was no difference between the aspirin and heparin groups. The finding that heparin inhibited platelet deposition to a degree comparable with aspirin suggests that it may not be necessary to start antiplatelet therapy preoperatively. Intraoperative systemic heparinization will provide sufficient inhibition of platelet deposition. A protocol for perioperative antiplatelet therapy is outlined.

Acute adrenal insufficiency mimicking septic shock: a case report.

Acute adrenal insufficiency is an unusual problem that may mimic overwhelming sepsis. Elevated cardiac output and low systemic vascular resistance in a patient with known risk factors should alert clinicians to the possibility of that condition.

Correlation of clinical findings with venous hemodynamics in 386 patients with chronic venous insufficiency.

Deep venous insufficiency secondary to deep valvular incompetence predominated over superficial venous insufficiency in an unselected patient population with advanced chronic venous insufficiency. Venous obstruction was uncommon (5 percent), suggesting that venous bypass surgery may have limited applicability in the management of chronic venous insufficiency. Although the majority of patients (72 percent) with stage III venous disease (ulcer) had deep venous insufficiency alone and would be potential candidates for deep valvular reconstruction, 13 percent were found to have superficial venous insufficiency alone, and the remaining 15 percent, deep venous insufficiency with a hemodynamically significant component of superficial venous insufficiency. These findings suggest that not all patients with stage III disease have altered hemodynamics on the basis of deep venous valvular incompetency. Although most stage III chronic venous insufficiency is secondary to altered deep venous hemodynamics, as demonstrated by shortened venous refill time, there is a significant group of patients with severe chronic venous insufficiency having superficial venous insufficiency alone or in combination with deep venous insufficiency (28 percent). Thus, it is imperative that those patients with superficial venous insufficiency be identified by a widely available and reproducible method, such as light reflection rheography, since they may respond to surgery of the superficial venous system alone.

Clinical and hemodynamic results of bypass to isolated tibial artery segments for ischemic ulceration of the foot.

Patients with ischemic ulceration of the foot and no continuous tibial or inframalleolar vessels acceptable for bypass are often treated with primary amputation. We have performed autogenous vein bypass to isolated tibial artery segments (ITAS) in nine patients with ischemic foot ulcers and no other outflow options. We reviewed the clinical and hemodynamic results of these bypasses to assess the efficacy of this approach. Hemodynamic comparisons of these ITAS bypasses were made to a concurrent series of 26 bypasses to intact tibial arteries and 24 inframalleolar artery bypasses assessed during routine follow-up. Eight of the bypasses originated from the above-knee popliteal artery and one from the profunda femoris artery. Recipient vessels were the anterior tibial (seven), peroneal (one), and posterior tibial (one) arteries. Although mean ankle brachial indices (ABI) increased significantly from 0.26 +/- 0.06 preoperatively to 0.75 +/- 0.04 postoperatively (p = 0.0015), ITAS bypass patients had lower mean postoperative ABIs than patients with bypasses to intact tibial (ABI = 0.98 +/- 0.03, p = 0.0001) or pedal arteries (ABI = 1.02 +/- 0.04, p = 0.0005). Similarly, duplex scan-derived peak systolic flow velocities of the ITAS bypasses (mean: 52.9 +/- 5.8 cm/sec) were lower than those of intact tibial artery bypasses (mean: 80.1 +/- 6.1 cm/sec, p = 0.02) but did not differ from those of pedal bypasses (mean: 59.5 +/- 3.5 cm/sec, p = 0.34). No ITAS bypass grafts have failed during a mean follow-up of 12.3 +/- 2.7 months. Although wound healing was prolonged (mean: 3.1 +/- 0.6 months), the wounds of eight of nine patients eventually healed, with three patients requiring minor amputations (one digital amputation and two transmetatarsal amputations). Although the hemodynamic results of ITAS bypass are inferior to those of more conventional bypasses, the early patency rates and successful healing of ischemic wounds confirm that it is a valid alternative in the threatened limb with no other outflow options.

Improvements in the diagnosis and management of aortoenteric fistula.

To assess the impact of an aggressive approach (early operation, graft removal, and extraanatomic bypass) adopted by us 5 years ago in patients with aortic synthetic grafts and gastrointestinal bleeding, we reviewed our 15 year experience with aortoenteric fistula in 13 patients. The courses of six patients from the recent series (1979 through 1984) were contrasted with those of seven patients from our earlier series (1968 through 1978). Twelve of 13 patients presented with gastrointestinal bleeding (usually low volume), and no patient presented in shock. Six of seven patients in Series I (earlier series) had positive blood cultures, whereas only two of six in Series II (recent series) had this finding. Of the 13 patients, 10 underwent preoperative endoscopy. It was only with consistent visualization of third and fourth portions of the duodenum that a diagnosis of aortoenteric fistula was established (three of four patients 75 percent). Although the upper gastrointestinal series was abnormal more frequently (five of seven patients, 71 percent) than arteriograms (three of nine patients, 33 percent), the latter was more specific for a predisposing lesion. At surgery, nine (70 percent) patients had an anastomotic fistula and four (30 percent), a false aneurysm. Although only one of seven patients in Series I survived (14 percent), four of six patients in Series II were alive at last follow-up in September 1984 (67 percent). Early diagnosis followed by prompt operation with removal of the synthetic graft and extraanatomic bypass is associated with an improved survival for patients with aortoenteric fistula, but the degree of preoperative sepsis as indicated by positive blood cultures appears to be an important prognostic sign.

Who needs surveillance of the contralateral carotid artery?

BACKGROUND: Although the value of carotid endarterectomy has been proven, postoperative surveillance remains controversial. The purpose of this study was to determine the natural history of disease progression in the contralateral carotid artery by duplex surveillance, and to assess the cost of stroke prevention on this contralateral side. METHODS: Vascular laboratory records were reviewed to identify carotid endarterectomy patients who had two or more duplex studies between 1984 and 1995. Critical stenosis was defined as > or = 75% area reduction. RESULTS: In all, 324 patients were followed up with duplex scans for 1 month to 11 years (mean 30.3 months). The only factors that correlated with progression to critical stenosis were age and initial stenosis. Overall, 19.5% of patients progressed to critical stenosis within 5 years while the high-risk groups with age > 65 years or initial stenosis > or = 50% progressed to critical disease in 27% and 39%, respectively (P < or = 0.05). The cost per stroke prevented ranged from $143,500 to $418,200 when stratified by initial stenosis. CONCLUSION: Patients who have undergone a carotid endarterectomy demonstrate a propensity for progression of carotid stenosis in the unoperated (contralateral) artery. The cost/benefit ratio may be improved by varying the intensity of duplex surveillance of the contralateral carotid based on the patient's age and initial degree of stenosis.

Evaluation of arterial prostheses in a baboon ex vivo shunt: the effect of graft material and flow on platelet deposition.

Surface thrombogenicity is recognized as an important factor in the failure of small caliber vascular prostheses. The baboon ex vivo shunt was developed to study small caliber grafts under controlled conditions at different flow rates. The shunt was created by percutaneous insertion of catheters into the baboon femoral artery and vein. Platelet-graft interactions were studied using autogenous indium 111 labeled platelets. Two graft materials were placed in series and exposed to blood flow for 2 1/2 hours at flow rates of 25 and 200 ml/min. At the end of this period, the grafts were removed for morphologic examination. Platelet adhesion to the grafts, especially with the less thrombogenic materials (PTFE and HUV), was found to be independent of flow rate. PTFE was found to be the least platelet-reactive material, HUV was intermediate, and knitted Dacron was the most thrombogenic surface. Platelet deposition on the flow surface was confirmed by light microscopy and scanning electron microscopy.

Infrarenal aortic occlusion: a reassessment of surgical indications.

Citing a high incidence of proximal propagation of aortic thrombosis, several authors have advocated aortic reconstruction for all patients with infrarenal aortic occlusion irrespective of their preoperative symptoms and potential operative risks. To test this thesis, the records and follow-up data of 38 patients seen at our institution between 1965 and 1982 with infrarenal aortic occlusion were analyzed. Twenty-four of the 38 patients were treated surgically (Group I); 16 (42 percent) had an aortobifemoral graft and 8 (21 percent) had an axillofemoral bypass graft. When the 14 patients who did not have surgery (Group II) and the 8 patients who had an axillofemoral graft were combined, 22 patients (58 percent) did not have aortic reconstruction (Group III), thus the aortic thrombus was left in situ. There was no significant difference in cumulative survival between the three groups at 4 year follow-up. Of 13 patients in Group III who were followed for more than 6 months (mean 48 months), none died from proximal propagation of aortic thrombosis. The decision for surgical intervention in patients with distal aortic occlusion should be arrived at, as in other patients with aortoiliac occlusive disease, by weighing preoperative symptoms and operative risks and not primarily by the level of risk of proximal propagation of thrombosis.

Transesophageal echocardiography for hemodynamic management of thoracoabdominal aneurysm repair.

Maintenance of cardiovascular stability during thoracoabdominal aneurysm repair remains a formidable challenge. Transesophageal echocardiography (TEE) has been shown to be an excellent method for detecting myocardial ischemia and assessing left ventricular volume. We examined the utility of TEE in a group of 17 patients from an overall series of 33 patients who underwent thoracoabdominal aneurysm resection between 1988 and 1992. The mortality rate was 9%, whereas the incidences of myocardial infarction and paraplegia were 13% and 6%, respectively. Intraoperative management was significantly altered by TEE data in nine patients. Two patients were noted to have mitral valve insufficiency, and one had transient ischemia-induced regional wall abnormalities. In six patients, Swan-Ganz-derived filling data failed to identify severe hemodynamic alterations that were noted on TEE. Five patients were hypovolemic and hyperdynamic, whereas one was in florid congestive heart failure. Further investigation is warranted to prospectively validate this technique.

Neuroleptics block the positive reinforcing effects of amphetamine but not of morphine as measured by place conditioning.

The role of dopamine brain systems in mediating the rewarding effects of opiates and stimulants was investigated using the conditioned place preference paradigm. The effects of the neuroleptics alpha-flupentixol (0.8 mg/kg, IP) and haloperidol (1.0 mg/kg, IP) were tested against the place preferences produced by morphine sulphate (1.0 and 5.0 mg/kg, SC), d-amphetamine sulphate (1.0 mg/kg, IP) and cocaine hydrochloride (5.0 mg/kg, IP). Amphetamine place preference was successfully blocked but neuroleptic pretreatment had no effect on the place preferences produced by cocaine and morphine, alpha-Flupentixol alone produced no place conditioning. These results support the hypothesis of dopamine involvement in amphetamine reward. However, morphine reward, as measured by the conditioned place preference paradigm, appears not to be critically dependent on brain dopamine systems.