High precision isotope measurements reveal poor control of copper metabolism in parkinsonism.

Disordered copper metabolism may be important in the aetiology of Parkinsonism, as caeruloplasmin is a key enzyme in handling oxidative stress and is involved in the synthesis pathway of dopamine. The human Cu metabolism of ten Parkinsonism patients was compared to ten healthy controls with the aid of a stable (65)Cu isotope tracer. The analyses of blood serum (65)Cu/(63)Cu ratios yielded individual isotopic profiles, which indicate that the Cu metabolism is less controlled in patients with Parkinsonism. Modelling based on both isotope tracer and total Cu concentrations suggests that 30% of the subjects affected by Parkinsonism have abnormally large Cu stores in tissues. To detect the small differences in Cu metabolism between Parkinsonism and controls, the analysis of stable isotope composition must be performed using multiple-collector inductively coupled plasma mass spectrometry and the associated sample preparation techniques. This pilot investigation supports full-scale medical studies into the Cu metabolism of those with Parkinsonism.

Accuracy of intravascular ultrasound for diameter measurement of phantom arteries.

BACKGROUND: Uniplanar quantitative angiography (QA) is the standard method for measuring vessel diameter during surgical and endovascular procedures. Intravascular ultrasound (IVUS), a relatively new technology, is another means of obtaining this measurement. This study was designed to validate the accuracy of these two modalities by comparing each to direct caliper measurement, the gold standard, using phantom femoral artery segments (PAS). MATERIALS AND METHODS: PAS diameter was measured with a 12.5-MHz mechanically rotating IVUS catheter (Boston Scientific Corp.) and QA (OEC Corp.) was compared to the direct caliper measurement (Mitutoyo Corp.) at 60 different locations within PAS. At each location minimal lumen diameter and perpendicular lumen diameter were measured and their mean was calculated. The intraclass correlation coefficients (ICCC) between direct caliper measurement and IVUS and uniplanar and biplanar angiography were calculated. Fisher's Z transformation was used to compare the correlation coefficients. RESULTS: The ICCC for IVUS was 0.89. The ICCCs for uniplanar and biplanar angiography were 0.73 and 0.82, respectively. IVUS correlated more closely with direct caliper measurement than uniplanar and biplanar angiography (P = 0.00008, 0.02) Biplanar angiography correlated more closely with direct caliper measurement than uniplanar angiography (P = 0.04). CONCLUSIONS: IVUS more accurately measures lumen diameter than uniplanar or biplanar angiography. Diameter measurement with biplanar angiography is more accurate than uniplanar angiography.

Identification of uric acid and xanthine oxidase in atherosclerotic plaque.

Concentrations of uric acid in carotid endarterectomy specimens in men and women were measured using high-performance liquid chromatography in comparison wo nonatherosclerotic control specimens.

Analysis of nonpenetrating clips versus sutures for arterial venous graft anastomosis.

The use of nonpenetrating clips (NPC) for vascular anastomosis is quickly becoming accepted. Studies attest to decreased anastomotic time, comparable patency rates, and decreased blood loss. Few human studies on the use of NPC have been done to date. The purpose of this study was to evaluate primary patency rates, operative time, and complications associated with NPC compared to those with standard sutures for arterial venous graft (AVG). We retrospectively reviewed the clinical course of 82 patients with a mean age of 45 years (range, 22 to 87) from February 1996 to July 1999. All patients underwent upper extremity AVG construction. The procedures were performed at a single institution, by a single, well-experienced surgeon who has extensive experience with NPC. Primary patency rates, operative time, and complications were analyzed. Overall thrombotic incidence of AVG when NPC were used (27/48, 56%) was similar to that of sutures (17/34, 50%). Thrombotic incidence within the first year was similar as well (23/48, 48% and 13/34, 38%). The mean time to primary thrombosis was similar in both groups (6.9 and 6.8 months). The operative time required to construct an AVG with NPC (83 min) was significantly less than that with sutures (96 min) (p = 0.015). There was no significant difference in incidence of graft infection or pseudoaneurysm formation. NPC for AVG reduced operative time and resulted in primary patency and complication rates similar to those associated with use of sutures. The mean time to primary thrombosis was similar for both groups. Our findings suggest an intimal hyperplastic response of a similar nature resulting in thrombosis of both NPC and sutured AVGs.

Impaired venous hemodynamics in a minority of patients with chronic leg ulcers due to sickle cell anemia.

BACKGROUND: Chronic or recurrent leg ulceration occurs in 25% of sickle cell anemia patients, but not in the remaining 75%. Doppler studies of venous function were normal in 16 sickle cell anemia patients with leg ulcers. PATIENTS AND METHODS: Venous Duplex Ultrasound was used to study 33 sickle cell anemia patients with chronic leg ulcers. RESULTS: Six of the 33 patients had venous reflux in at least one leg. CONCLUSIONS: Venous insufficiency may contribute to the development of leg ulcers in a minority of sickle cell anemia patients. A minority of sickle cell anemia patients with chronic leg ulcers can be shown to have leg venous reflux by duplex ultrasound imaging.

Can preoperative spiral CT scans alone determine the feasibility of endovascular AAA repair? A comparison to angiographic measurements.

PURPOSE: To determine whether computed tomography (CT) alone can be used for excluding patients from endovascular repair for abdominal aortic aneurysms (AAA). METHODS: Among 71 patients evaluated for endovascular AAA repair using spiral CT imaging and angiography, 31 were selected who had both studies performed within 6 months of each other using a graduated measuring catheter or guidewire. Measurements of aneurysm neck diameter, neck length, and infrarenal aortic length were made from the CT and angiographic images using handheld calipers with calibration markers as guides. Infrarenal aortic length and neck length were determined from CT images by multiplying the width of the cuts by the number of slices between the lowest renal artery and the aortic bifurcation or the top of the aneurysm, respectively. RESULTS: CT neck diameter measurements differed significantly from the angiographic dimensions (6.3 +/- 5.1-mm mean difference, p < 0.001). In the majority of patients (25, 81%), CT neck diameters were larger (mean 7.3 +/- 3.8 mm). The mean difference in neck length measurements was 0.5 +/- 15.9 mm (p = NS). Twenty-two (71%) patients had aortic length measurements that were longer on the angiogram (mean 15.4 +/- 17.2 mm, p = NS). Five patients who would have been excluded as candidates based on overestimated CT neck diameter measurements subsequently underwent successful endovascular aneurysm repair. CONCLUSIONS: Considerable discrepancies exist between preoperative neck diameter and infrarenal aortic length measurements obtained from CT scans and angiograms used to evaluate candidates for endovascular aortic aneurysm repair. CT alone may not be adequate for predicting the feasibility of endovascular AAA repair.

Histology and electron microscopy of explanted bifurcated endovascular aortic grafts: evidence of early incorporation and healing.

PURPOSE: To report an examination of explanted bifurcated endovascular aortic grafts for histologic evidence of early healing and incorporation. METHOD: Two bifurcated endovascular aortic grafts composed of polycarbonate urethane and Elgiloy wire were explanted 42 and 21 days after successful endovascular exclusion of abdominal aortic aneurysms. Both patients expired from causes unrelated to endograft deployment. The explanted devices were examined using immunohistochemical analysis and electron microscopy. RESULTS: On explantation, both grafts appeared to have excluded the aneurysm with no evidence of endoleak, graft migration, or thrombosis. Histological examination showed numerous inflammatory cells and good ingrowth of tissue into the proximal 2 cm of the graft. Collagen and smooth muscle cells were evident in the proximal portion of the graft with only collagen in the distal segments. Neointimal formation was seen within the proximal 2 cm also, but not at the distal segments. Macrophages were present in the graft. Scanning electron microscopy showed an extensive matrix of fibers that most likely represented collagen. CONCLUSIONS: Bifurcated endovascular aortic grafts show inflammatory and mild foreign body reactions, collagen formation, and intimal ingrowth during healing. These findings are similar to some of the healing properties reported for sutured grafts, as well as other endovascular grafts.

Endoluminal repair of aneurysms containing ostia of essential branch arteries: an experimental model.

PURPOSE: To examine experimentally the feasibility of transfemoral endoluminal repair of aneurysms containing the ostia of essential branch arteries. METHODS: In a canine model (n = 4), suprarenal aortic aneurysms were created by suturing an artificial patch onto an anterior arteriotomy. Following a 2-week recovery period, the dogs underwent endovascular exclusion of their aneurysms using an aortic stent-graft with separate renal artery branch grafts. Outcome was evaluated using angiography, intravascular ultrasound (IVUS), Doppler flow, invasive pressure monitoring, and autopsy, respectively. RESULTS: Successful creation and subsequent endovascular exclusion of the aneurysm using aortic stent-grafts and separate bilateral renal artery stent-grafts was achieved in all trials. Angiographically, all aneurysms were excluded from aortic flow and all renal arteries were patent at completion of the procedure. With IVUS, good graft apposition and absence of perigraft flow were demonstrated in all animals. Mean pressure in the aneurysmal sac at completion of the procedure was 40 +/- 7 mmHg, compared to a mean systemic blood pressure of 105 +/- 8 mmHg (p < 0.05). At autopsy, no gross intimal damage was seen in the aorta or the renal arteries, and intact aortic grafts and branch grafts without twisting, coiling, or kinking were found in all trials. CONCLUSIONS: In an acute animal model, suprarenal aortic aneurysms can be excluded from the circulation with preservation of renal flow using an endoluminally placed aortic stent-graft with separate branch grafts.

Repair of type IV thoracoabdominal aneurysm with a combined endovascular and surgical approach.

We report an unusual case of type IV Thoracoabdominal Aneurysm (TAA) with Superior Mesenteric Artery (SMA), celiac artery, and bilateral renal artery aneurysms in a patient who underwent an earlier repair of two infrarenal Abdominal Aortic Aneurysm (AAA) ruptures. Because of the presence of the visceral artery aneurysms and the earlier operation through the retroperitoneum, standard surgical treatment via a retroperitoneal approach with an inclusion grafting technique was considered difficult. A combined surgical approach achieving retrograde perfusion of all four visceral vessels and endovascular grafting allowing exclusion of the TAA was accomplished. Complete exclusion of the aneurysm and normal perfusion of the patient's viscera was documented by means of follow-up examinations at 3 and 6 months. The repair of a type IV TAA with a Combined Endovascular and Surgical Approach (CESA) allowed us to manage both the aortic and visceral aneurysms without thoracotomy or re-do retroperitoneal exposure and minimized visceral ischemia time. If the durability of this approach is confirmed, it may represent an attractive alternative in patients with aneurysmal involvement of the visceral segment of the aorta.

Medium molecular weight pentastarch reduces reperfusion injury by decreasing capillary leak in an animal model of spinal cord ischemia.

PURPOSE: The medium molecular weight fraction of pentastarch (HES-Pz) has been shown to decrease reperfusion injury to myocardium and brain by reducing capillary leak. This study was undertaken to assess the effects of HES-Pz on neurologic function, microvascular permeability, and spinal cord infarction after temporary aortic cross-clamping in a rabbit model. METHODS: In 30 New Zealand White rabbits, a snare occlusion device was placed around the infrarenal aorta and tunneled into a subcutaneous position. Animals were allowed to recover for 48 hours and were randomized into three groups. In each group, the infrarenal aorta was occluded by tightening the snare in the awake animal for 21 minutes. Immediately after unclamping, animals received an intravenous infusion of 4% of their estimated blood volume of one of the following solutions: normal saline solution (NS; group 1); 6% standard hydroxyethyl starch (HES), molecular weight 10 to 3400 kD (group 2); and 6% HES-Pz, molecular weight 100 to 1000 kD (group 3). During 5 days of observation, neurologic recovery was graded by an independent observer using the Tarlov scale. Animals were then killed and their spinal cords harvested for histologic examination using hematoxylin-eosin and 2,3,5-triphenyltetrazolium chloride staining. In a separate group of animals (n = 15), the occurrence of spinal cord capillary permeability after NS, HES, and HES-Pz infusions was evaluated by spectrophotometric analysis of extravasated Evans blue. RESULTS: Complete paraplegia and marked histologic evidence of spinal cord cellular injury were seen in 90% of group 1 (NS) and in 78% of group 2 (HES). Treatment with HES-Pz (group 3) resulted in full neurologic recovery in 89% of animals (p < 0.05) and a threefold reduction of extravasated Evans blue compared with controls (p < 0.05). CONCLUSIONS: These results indicate that microvascular hyperpermeability plays an important role in reperfusion injury to the spinal cord. Treatment with HES-Pz reduced the capillary permeability, neuron membrane injury, and incidence of paraplegia after reperfusion of ischemic spinal cord in a rabbit model.

Endoluminal treatment of vascular occlusive disease.

The logical desire to avoid major cutaneous incisions and surgical dissection in the treatment of vascular occlusive disease has, in recent years, led to a surge of new therapeutic options whereby access to the diseased blood vessel is obtained via a distant site and treatment is effected from within the vessel. Such endoluminal treatment modalities include thrombolysis, balloon angioplasty, atherectomy, stenting, and stent grafting. For the purpose of this surgically oriented article, the latter two techniques are discussed.

Combined carotid endarterectomy, innominate artery reconstruction, and coronary artery bypass grafting: case report.

Neurologic injury is one of the most devastating complications of combined carotid and cardiac procedures. Although the cause of the deficit is usually embolic, the exact cause is often not apparent at the time of surgery. We present a complex case of combined carotid endarterectomy, innominate artery reconstruction, and coronary artery bypass procedures in which intraoperative monitoring with somatosensory evoked potentials and transcranial Doppler ultrasonography combined with postoperative acetazolamide single photon emission computed tomographic scans was used to correlate intraoperative events with cerebral activity and functional results. Although computed tomographic scan, magnetic resonance imaging, and clinical evaluation were negative for any evidence of stroke, the patient exhibited subtle postoperative changes in neuropsychologic function. These changes were correlated with intraoperative microemboli detected by transcranial Doppler monitoring, and postoperative acetazolamide single photon emission computed tomographic scanning, which revealed bilateral cortical defects.

Somatosensory evoked potential monitoring during carotid surgery.

Controversy exists over the value of intraoperative monitoring and shunting in patients undergoing carotid endarterectomy. Although it is widely believed that contralateral carotid occlusion and previous stroke mandate intraoperative shunting, the susceptibility of these two groups of patients to cerebral ischemia during carotid artery endarterectomy is not well defined. Somatosensory evoked potentials (SSEPs) were monitored in 113 carotid artery endarterectomy patients. Of these, 32 (28.3%) had a previous stroke, 24 (21.2%) had a contralateral carotid occlusion and 33 (29.2%) were diabetic. There were no deaths and only one perioperative stroke (0.9%). Cerebral ischemia occurred in 14 patients (12.4%). Six of these patients had a contralateral carotid occlusion. Some 29 patients (25.7%) were shunted, including 10 with contralateral carotid occlusions that did not have major SSEP changes. In the latter half of the study, 14 patients with contralateral carotid occlusions were selectively shunted (six shunted, eight not shunted) with no neurological complications. Thirty-two patients with prior strokes were selectively shunted (nine shunted, 23 not shunted); of these, one shunted patient undergoing combined carotid artery endarterectomy and coronary artery bypass grafting had a perioperative stroke. Intraoperative monitoring with SSEPs accurately identifies cerebral ischemia secondary to carotid clamping as well as patients requiring shunts. With use of intraoperative SSEP monitoring, selective shunting may be safely performed in patients with a contralateral carotid occlusion or a previous stroke.

Atrial natriuretic peptide replacement therapy in rats subjected to biatrial appendectomy.

The postoperative fluid retention found in some patients after the Cox maze procedure has been attributed to surgically induced loss of atrial natriuretic peptide. We postulated that exogenous atrial natriuretic peptide could reverse this antidiuresis. A rat model was used to investigate this hypothesis. In group I, the sham group, the atrial appendages were left intact and the animals were then subjected to a fluid challenge equivalent to 1% of the animal's body weight. In group II, after biatrial appendectomy, the animals were subjected to a fluid challenge similar to that in group I. Animals in group III underwent the same protocol as that for group II plus intravenous administration of atriopeptin III at varying concentrations. Urine output and plasma atrial natriuretic peptide levels were significantly decreased after biatrial appendectomies (p < or = 0.01). Urine output returned to control levels after biatrial appendectomies with low-dose atrial natriuretic peptide infusion (0.5 pmol/min = 25.5 pg/min), although circulating atrial natriuretic peptide levels were lower. Urine output and plasma atrial natriuretic peptide levels increased with atrial natriuretic peptide infusions between 0.5 and 50 pmol/min. Heart rate and mean blood pressure did not vary significantly with atrial natriuretic peptide infusions. Thus atrial natriuretic peptide can be used effectively in low doses to induce a diuresis after biatrial appendectomies. Atrial natriuretic peptide may have clinical application after the Cox maze procedure.

Transluminally placed endovascular stented graft repair for arterial trauma.

PURPOSE: Intravascular stents have become important tools for the management of vascular lesions; however, stents in combination with vascular grafts have only recently reached clinical application. This report describes an experience with stented grafts for the treatment of penetrating arterial trauma. METHODS: Seven transluminally placed stented grafts were used to treat one arteriovenous fistula and six pseudoaneurysms. These grafts were successfully inserted percutaneously or through open arteriotomies that were remote from the site of vascular trauma. The devices were composed of balloon-expandable stainless steel stents covered with polytetrafluoroethylene grafts. RESULTS: Patency up to 14 months was achieved (mean follow-up 6.5 months) with these stented grafts. The use of stented grafts appears to be associated with decreased blood loss, a less invasive insertion procedure, reduced requirements for anesthesia, and a limited need for an extensive dissection in the traumatized field. These advantages are particularly important in patients with central arteriovenous fistulas or false aneurysms who are critically ill from other coexisting injuries or medical comorbidities. CONCLUSIONS: The use of stented grafts already appears justified to treat traumatic arterial lesions in critically ill patients. Although the early results with the seven cases in this report are encouraging, documentation of long-term effectiveness must be obtained before these devices can be recommended for widespread or generalized use in the treatment of major arterial injuries.