Xenograft seeding of Dacron grafts in dogs.

The benefit of autologous endothelial cell seeding in dogs has been widely accepted. This experiment seeks to determine if a similar effect accompanies the use of xenograft (porcine) endothelial cells in dogs. Thirty-two mongrel dogs underwent thoracoabdominal aortic bypass with 25- to 30-cm segments of double velour Dacron 8-mm grafts. Endothelial cell seeding was performed with whole blood suspensions of either autologous endothelial cells (Group I) or heterologous endothelial cells from pigs (Group II). Cell-free culture medium was added to whole blood for preclotting in unseeded control animals (Group III). Ten animals in each group were sacrificed at 30 days and all grafts were patent. Thrombus-free surface areas were Group I = 61.7 (+/- 6.4%, SEM); Group II = 53.2 (+/- 6.8%, SEM); and Group III 42.2 (+/- 8.0%, SEM). There was a significant difference between autologous-seeded and unseeded grafts (P less than 0.04). Endothelialization was confirmed by scanning and transmission electron microscopy in all groups but was better in both seeded groups: Group I-9/10 grafts, Group II-8/10 grafts, and Group III-4/10 grafts. Factor VIII immunofluorescent staining confirmed the presence of endothelium on selected grafts in each group. These results raise questions concerning the proposed mechanism of endothelial seeding since xenograft cells seem to facilitate healing in the canine model. If heterograft cells can be effective, it may not be necessary to harvest cells from the recipient in order to achieve the benefits of seeding.

Are seeded endothelial cells the origin of neointima on prosthetic vascular grafts?

Although endothelial cell seeding has been demonstrated to be effective in producing uniform endothelial coverage on prosthetic grafts, no one has demonstrated that the seeded cells are the genetic precursors of the endothelial cells that ultimately line the graft. This study was performed to determine whether seeded endothelial cells were the source of the neoendothelial surface on Dacron vascular grafts implanted in the pig. Eight pairs of littermate male and female pigs were selected at birth and allowed to grow until their weight reached 20 to 25 kg. Endothelial cells were enzymatically harvested from the jugular vein of the female siblings and seeded onto 8 mm diameter grafts, 25 cm in length. The grafts were then implanted as a thoracoabdominal bypass into the male siblings. Seven other randomly selected pigs of similar size (four males and three females) had thoracoabdominal bypass with similar grafts, which were preclotted with autologous blood only, but not seeded. After 4 weeks, grafts in both groups were covered with a neointima that was more than 90% thrombus-free. The graft surface cells were grown in culture and were documented to be endothelium. Chromosome analysis demonstrated that the surface cells on the seeded grafts were from the male host and did not originate from the donor female cells. We conclude that seeded endothelial cells are not the source for the neointima on Dacron grafts in the porcine model. In addition, we have again documented that spontaneous endothelial coverage of grafts does occur without endothelial seeding.

Inflammatory abdominal aortic aneurysms: a thirty-year review.

The operative records of 2816 patients undergoing repair for abdominal aortic aneurysm (AAA) from 1955 to 1985 were reviewed. Inflammatory aortic or iliac aneurysms were present in 127 patients (4.5%), 123 men and four women. Most patients were heavy smokers (92.1%). Clinical evidence of peripheral arterial occlusive disease and coronary artery disease was found in 26.6% and 39.4%, respectively. Additional aneurysms occurred in half of the patients; iliac aneurysms were the most common (55 patients), followed by thoracic or thoracoabdominal (17 patients), femoral (16 patients), and popliteal aneurysms (10 patients). Ultrasound and computed tomography suggested the diagnosis in 13.5% and 50%, respectively; angiography was not helpful. Excretory urographic findings of medial ureteral displacement or obstruction suggested the diagnosis in 31.4%. The aneurysm was repaired in 126 patients. Only one patient experienced acute aneurysm rupture, but eight patients had chronic contained leakage. When compared with patients who have ordinary atherosclerotic aneurysms, patients with inflammatory aneurysms are significantly more likely to have an elevated erythrocyte sedimentation rate (ESR, 73% vs. 33%, p less than 0.0001); weight loss (20.5% vs. 10%, p less than 0.05); symptoms (66% vs. 20%, p less than 0.0001); and an increased operative mortality rate (7.9% vs. 2.4%, p less than 0.002). The triad of chronic abdominal pain, weight loss, and elevated ESR in a patient with an abdominal aortic aneurysm is highly suggestive of an inflammatory aneurysm and may be beneficial in the preoperative preparation of the patient for aneurysm repair.

Management of severe gastroesophageal reflux in children.

To evaluate response to fundoplication, clinical results for 66 consecutive pediatric patients operated on for gastroesophageal reflux were retrospectively reviewed. Indications for operation were gastroesophageal reflux with apnea, repeated emesis, recurrent pneumonia, failure to thrive, stricture, and esophagitis. All patients had preoperative documentation of significant gastroesophageal reflux by either cinefluoroscopic reflux esophagogram or reflux nuclear scan. Fundoplication was effective in 56 (87%) of 64 patients. None of the patients considered to be operative failures had persistent gastroesophageal reflux. Operative failures occurred primarily in patients with gastroesophageal reflux and apnea or recurrent pneumonia. More advanced diagnostic tests, such as pH monitoring, may help to select patients whose symptoms of apnea and recurrent pneumonia are truly due to reflux. Gastroesophageal reflux produces significant morbidity in pediatric patients and is well treated operatively by fundoplication.