Eluting characteristics of a platelet glycoprotein receptor antibody using a PLLA-coated stent.

Drug-eluting stents (DES) have emerged as a recognized alternative to treat stent restenosis but many questions remain regarding the optimal type and eluting characteristics of both drug and stent. The first component of the study examines the extent of surface coating of PLLA (poly(L-lactic acid)) on a Nitinol stent. The second characterizes the adsorption and elution rates of monoclonal mouse anti-human platelet glycoprotein (GP) IIIa antibody SZ-21 from a PLLA-coated surface. The PLLA coating was examined by fluorescence staining and image analysis using the Image Processing Box of MATLAB. Stents exposed to the monoclonal mouse anti-human platelet GP IIIa antibody were tested for their adsorption characteristics by radioisotope technique with (125)I-labelled SZ-21. The elution rates were then measured in looped circuits at different velocities (10 or 20 ml/min) and durations (30 min up to 312 h). Results showed that the fluorescence staining and image analysis showed a striking difference in the extent of coating between PLLA-coated stents and SZ-21 eluting stents on the gray-scale distribution of Nitinol surfaces. The amount of SZ-21 adsorbed onto the PLLA-coated stents was dependent on the concentration and duration of immersion in the solution. The method of preparation the mAb eluting stent significantly influenced the elution characteristics for a continuous perfusion of more than 300 h. The eluting curve was biphasic with initial rapid elution for the first 24 h followed by a gradual slow elution. These results indicate that the Image Processing Box of MATLAB appears to be a useful method for semi-quantitative analysis of fluorescence images. Furthermore, SZ-21 can be passively adsorbed onto PLLA-coated stents and predictably influenced by the concentration and duration of immersion. These studies may pave the way to developing stent-based delivery of a potent anti-platelet agent.

Carotid endarterectomy results in the early years of practice.

BACKGROUND: Newly qualified surgeons, as well as their referring physicians, are understandably anxious when dangerous surgery is contemplated. Carotid endarterectomy (CEA), which requires a low morbidity/mortality rate to be successful, is especially problematic in this realm. There is a paucity of literature indicating the results that can be expected when a less-experienced surgeon is asked to perform this procedure. As the volume of CEA surgery is expected to decrease in the future with improvements in endovascular techniques, there will be fewer highly experienced CEA surgeons around. METHODS: We studied the first consecutive, prospectively recorded 100 CEAs performed by each of two newly qualified surgeons (200 total) between January 1993 and May 1998. Standard technique was used and all cases were done under general anesthesia. The only difference in technique was the more liberal use of shunting and protamine by one individual. RESULTS: There were no significant differences in the patient demographics between the two surgeons. Seventy-five percent of the cases harbored symptomatic stenoses. An overall combined stroke/mortality rate of 5.5% was observed. The rate in those operated on for symptomatic stenosis (n = 150) was 6% while it was 4% for those with asymptomatic pathology. There were no significant differences in outcome between the two surgeons. The average stroke/mortality rate in the first 50 cases for each surgeon was 7%, as opposed to 4% for the second 50 cases. CONCLUSIONS: These data indicate that less-experienced individuals can perform this procedure with good results.

Appropriate imaging before carotid endarterectomy.

The question of which imaging method to use before performing carotid endarterectomy is a common and practical issue confronted by vascular surgeons. The imaging modalities of duplex ultrasonography, angiography, computed tomography (CT) and magnetic resonance angiography (MRA) have all been used in the preoperative assessment of the patient scheduled for carotid endarterectomy. This article focuses on these 4 modalities, with particular emphasis on the advantages and disadvantages of duplex ultrasonography versus angiography. The emergence of duplex ultrasonography as the sole preoperative imaging test has generated controversy among vascular surgeons and other specialists who deal with patients with carotid artery disease. Angiography, which has been the "gold standard" imaging test in the past and has been the reference standard in the large, randomized controlled trials, imposes a small but definite risk of stroke and death. Duplex ultrasonography can be used as the sole preoperative imaging test on a selective basis, provided that there is institutional validation and ongoing quality assurance. Although MRA is not widely available, the combination of MRA and duplex ultrasonography can provide similar diagnostic accuracy to angiography in some institutions. Routine CT appears to be unnecessary but is useful in certain circumstances.

Renal atrophy and arterial stenosis. A prospective study with duplex ultrasound.

Renal artery disease is an important cause of both renal failure and hypertension. Duplex ultrasound is a reliable noninvasive method for classifying the severity of renal artery lesions and can be repeated to follow the course of the disease over time. The purpose of this study was to determine the changes in kidney size associated with various degrees of renal artery disease. Serial kidney lengths were measured as part of a prospective duplex ultrasound study of patients with renal artery narrowing. Fifty-four patients (22 men, 32 women; mean age, 65.8 years) with 101 renal artery and kidney sides eligible for follow-up were evaluated at 6-month intervals for an average of 14.4 months (range, 4 to 24 months). No kidneys with renal arteries classified as normal or less than 60% diameter stenosis by duplex criteria were found to have a decrease in length of greater than 1 cm during follow-up. In kidneys with a high-grade renal artery stenosis (> or = 60% diameter reduction), 26% (13 of 49 sides) were found to have a decrease in length of greater than 1 cm. The average decrease in length was 1.9 cm (range, 1.2 to 3.4 cm). By life table analysis, the estimated risk of a decrease in length of greater than 1 cm for kidneys with 60% stenosis or greater was 19% at 1 year. Loss of renal mass, as documented by ultrasound measurement of kidney length, is an important consequence of high-grade renal artery stenosis.

Primary malignant melanoma of the esophagus with diffuse melanocytic atypia and melanoma in situ.

Primary malignant melanoma is an unusual lesion in the esophagus that is not infrequently seen in association with melanosis. A case of esophageal invasive malignant melanoma with melanosis is described in which the melanosis exhibited melanocytic atypia extending through to melanoma in situ. The authors know of no previously reported such finding.