A balloon-expandable intravascular stent for obliterating experimental aortic dissection.

Acute aortic dissection is a life-threatening condition. Aggressive hypotensive drug therapy is the initial treatment of choice, although emergent surgical intervention is often warranted. We evaluated the efficacy of a balloon-expandable intravascular stent for the internal obliteration of aortic dissection. It is a flexible, continuous, complex coil cut to the length needed at the time of insertion. It can be positioned in curved vessels, including the aortic arch. The stent was inserted in the thoracic and abdominal aorta of 12 dogs (group I). Six weeks after implantation the dogs underwent angiography and the stents were explanted for light and scanning electron microscopy. There were no instances of stent migration or change in configuration. The aortas did not rupture. All branch vessels remained patent. Light and scanning electron microscopy illustrated neointimal incorporation into the vascular wall except at orifices. Thoracic dissections were created surgically in an additional 24 mongrel dogs. Twelve dogs received stents immediately after creation of the dissection (group II). All 12 dissections were obliterated. Twelve dogs were allowed to recover after creation of the dissection to observe the natural history of that lesion (group III). Within 1 week, in group III, there were three deaths because of aortic rupture; eight dissections persisted, and one resealed spontaneously. Stents were placed in the eight persistent dissections. All eight dissections were obliterated. In both groups, after 6 weeks of stent placement, aortography was repeated, and stents were explanted for light and scanning electron microscopy. There were no instances of rupture. All branch vessels remained patent with no evidence of thrombosis. We conclude that because of its unique characteristics, the stent effectively obliterates the false lumen of experimental acute aortic dissections without occlusing side branches, damaging the aorta, or inducing thrombosis.

Prognostic value of morphometry in papillary thyroid carcinoma.

The value of morphometric analysis in addition to standard prognostic indicators was studied in 28 cases of papillary thyroid carcinoma. Standard features included age, sex, lymph node status, tumor size, and encapsulation. The mean follow-up was 47 months (maximum, 140 months). Recurrences were documented in six patients at a mean time of 34 months; five patients recurred with distal metastases and one patient recurred with local disease. Univariate analysis most closely associated tumor recurrence with nuclear anisotropism (the standard deviation of the estimated nuclear area [ENASD]) and tumor size. With forward stepwise incremental analysis, the value of tumor size was lost and only the ENASD and the cellularity mean index (CMI), defined as the percentage of tumor volume composed of tumor cells, significantly correlated with recurrence. Fifty-five percent of patients with an ENASD greater than 17 microns2 and a CMI greater than 40% developed recurrence as compared with 5% of patients with lesser values (P = .0001). Morphometric analysis may significantly contribute to the role of histopathology in the evaluation of papillary thyroid carcinoma and may also provide information regarding prognosis not obtained by standard methods.

Xanthogranulomatous pyelonephritis in a renal allograft.

We report a case of xanthogranulomatous pyelonephritis in a cadaver kidney allograft. The patient had diabetic glomerulosclerosis. The predisposing factors that led to this condition included hyperglycemia, a previous rejection reaction and Escherichia coli urinary infection. Persistent fever, pyuria, bacilluria and a nonfunctioning allograft resulted in allograft nephrectomy. The diagnosis was made on histological examination. Diagnostic criteria for xanthogranulomatous pyelonephritis in the allografted kidney are similar to those in the native kidney.