Search

Purpose: This experiment was designed for the determination of the optimal epidural cooling temperature for the allowance of spinal cord protection with minimal side effects during an aortic occlusion-induced spinal cord ischemia model in rabbits. Methods: Spinal cord ischemia was induced in rabbits with infrarenal aortic occlusion for 40 minutes. Spinal cord cooling was effected with epidural infusion of normal saline solution at the following different temperatures: group 1, 17°C (n = 6); group 2, 24°C (n = 6); group 3, 32°C (n = 6); and group 4, 39°C (n = 3). Sham-operated rabbits without aortic occlusion were used as controls with epidural infusion at healthy body temperature (39°C; n = 3). Motor function was assessed at 48 hours with Tarlov's criteria, and the animals were killed. The spinal cord was sectioned into multiple segments, and semiquantitative histologic scoring (0 to 5) was used to grade ischemic injury. Results: Cooling solution and spinal cord temperatures showed linear correlation (r = 0.95). All the rabbits in groups 1 (except one with mild weakness), 2, and 3 were neurologically intact, and all in group 4 had paraplegia develop (P

Objective: The purpose of the current study was to identify the possible short- and long-term effects of diabetes on the outcome of carotid endarterectomy. Methods: Medical records were reviewed for 781 carotid endarterectomies (in 734 patients) performed by the same vascular surgeon in a university medical center between January 1994 and December 1998. Patients were divided two groups: those with diabetes (n = 181 patients; 193 operations) and those without diabetes (n = 553; 588 operations). The two groups were similar with respect to mean age, male-female ratio, and contralateral lesions. The only significant differences were a higher prevalence of peripheral vascular disease and dyslipidemia in the diabetic group and a higher prevalence of hemispheric transient ischemic attacks among the nondiabetic patients. Carotid color duplex ultrasound scan had been performed in all patients, and in 56 patients from the diabetic group and 56 patients from the nondiabetic group (matched for age, sex, and contralateral lesions), the distal extension of the lesion from the carotid bifurcation had also been defined. Both of these subgroups were fully representative of their respective groups of origin. Carotid endarterectomy was performed after the induction of general anesthesia; electroencephalographic monitoring was continuous. Results: Except for the significantly higher prevalence of calcified plaques in the diabetic patients (P

Purpose: The experiments were designed to compare the effects of thrombolytic therapy (TL) and balloon-catheter thrombectomy (TX) on valvular competence, thrombogenicity, venous wall morphology, and function after acute deep venous thrombosis (DVT) in canine veins. Methods: The femoral veins of male mongrel dogs were ligated proximally and distally for 48 hours to induce DVT. The thrombosed veins were treated with either TL (n = 5) or TX (n = 9), or no treatment was rendered (n = 6). Sham-operated dogs were used as controls. TL was performed with catheter-directed infusion of urokinase at 4000 U/min for 90 minutes. Three hours after the treatment, the valvular competence was determined with duplex scanning, thrombogenicity determined with deposition of radio-labeled platelet and fibrin, and function determined with response to contractile and relaxing agonists in organ chambers. The structural integrity of the endothelial layer was assessed by means of scanning electron microscopy. Results: The removal or lysis of the thrombus was successful in all cases. The valvular competence did not differ among the groups. The platelet deposition was the highest after TX (P < .05), and the fibrin deposition was not significantly different among the groups. In the organ chamber experiments, relaxations to adenosine diphosphate and nitric oxide were reduced after TX (P < .05). The contractions to serotonin were enhanced after TX. Scanning electron microscopy results showed a comparable (51% to 75%) endothelial loss with either treatment. Conclusions: After experimental acute DVT, the TL and the TX at 3 hours had similar effects on the valvular competence and the endothelial morphology. However, the TL reduced thrombogenicity, which is consistent with the preserved endothelial responses to platelet products. These data suggest that TL may preserve vein function after DVT and may reduce the long-term potential for recurrent DVT and post-thrombotic syndrome. (J Vasc Surg 1998;28:787-99.)

The delay phenomenon in the transverse rectus abdominis myocutaneous (TRAM) flap was studied by means of a laser-Doppler flowmeter and an echo color-flow Doppler device. Twenty-eight patients who underwent breast reconstruction with a TRAM flap in our hospitals were analyzed. Eighteen of them underwent selective delay 1 month before the major surgical procedure, and of them, 15 completed the reconstructive procedure. Ten patients were used as a control group and underwent TRAM flap breast reconstruction without selective delay. Cutaneous blood flow in the TRAM flaps was measured in 20 patients with a laser-Doppler flowmeter, and measurements were taken before, during, and after the surgical procedure, following a standardized protocol, as in Tuominen's original scheme. Variations in the cutaneous blood flow in the standard TRAM flap (10 patients) confirmed data obtained from the literature, i.e., an increase when elevating the cutaneous and subcutaneous parts of the flap and a decrease when ligating the deep inferior and superficial epigastric vessels. Compared with the standard TRAM flap, blood flow in the delayed flaps (10 patients) seemed to be more stable, without falling under the baseline. When elevating the cutaneous and subcutaneous parts of the flap (phase 3), blood flow values reached 120.2 percent (SEM 46.8 percent) on the random side and 131.6 percent (p0.009, SEM 9.58 percent, standard deviation 30.3 percent) on the axial side. During phase 4 (cutting the rectus muscles), blood flow values reached 115.0 percent (SEM 40.5 percent) on the random side and 102.8 percent (SEM 1.2 percent, standard deviation 3.8 percent, p0.049) on the axial side. In order to obtain further hemodynamic data, 10 patients who underwent selective vascular delay 1 month prior to breast reconstruction with a delayed TRAM flap in our hospitals were then studied by means of an echo color-flow Doppler device. Two of these patients also had been studied with the laser-Doppler flowmeter. Superior epigastric artery diameter (in millimeters) and resistivity (expressed as Pourcelot's index) were measured before and after selective delay of the deep and superficial inferior epigastric vessels, following a standardized protocol. Measurements were taken with 7.5- and 10-MHz linear probes at a point located after the origin of the costomarginal artery. In every patient an increase in the superior epigastric artery diameter and a decrease in the resistivity index were observed, and this was statistically significant. In the nonirradiated patients, the increase in the average diameter of the superior epigastric artery was 98.1 percent, and the average resistivity index decrease was 14.1 percent. In the irradiated patients, the increase in the average diameter of the superior epigastric artery was 35.5 percent, and the average resistivity index decrease was 29.8 percent. In conclusion, laser-Doppler flowmeter evaluations show that cutaneous blood flow in the delayed flap is more constant and undergoes fewer variations than that in the standard TRAM flap. In addition, echo color-flow Doppler indicates that the basis for the increase in the vascular territory of the superior epigastric artery caused by the delay maneuver is an increase in the superior epigastric artery diameter, always accompanied by a decrease in the resistivity index. Two different mechanisms seem to us to be related to these modifications in the blood circulation. In the nonirradiated patients, superior epigastric artery dilation prevails, whereas in the irradiated patients, a decrease in the resistivity index is the dominant mechanism of compensation. These hemodynamic findings well support the decrease in flap necrosis reported in our series (standard TRAM: 30 percent; delayed TRAM: 7.1 percent).