Incomplete endothelialization of an intravascular implant and fatal late-onset bacterial ductal arteritis in a dog with occluded patent ductus arteriosus.

An 18-month-old male Akita Inu dog developed fever and lameness 8 months after successful transcatheter closure of a patent ductus arteriosus with an Amplatz Canine Duct Occluder (ACDO). Corynebacterium species were cultured from 3 blood samples. Echocardiography showed a vegetative process on the aortic valves. The dog died spontaneously 3 days after development of the initial signs. Necropsy confirmed the presence of bacterial ductal arteritis and myocarditis, and revealed an incomplete endothelialization of the intraductal metal implant. The reason for the lack of (neo)endothelialization of the ACDO remains unknown. We conclude that late-onset bacterial device-related ductal arteritis can develop in dogs where the implant is incompletely covered by a protective endothelial layer.

Vascular ultrasound studies for the non-invasive assessment of vascular flow and patency in experimental surgery in the pig.

Vascular ultrasound is a reliable non-invasive tool used for the routine assessment of vascular flow and patency in human recipients. We describe the use at three different time points (immediately, 1 week and 4 weeks postsurgery) of ultrasound studies and its validation by angiographic studies in 37 swine undergoing carotid graft replacement. We calculated predictive values (>92%), sensitivity (>85%) and specificity (>92%) with high results at all time points. Ultrasound appeared as an accessible non-invasive technique, providing rapid, safe, repeatable and reliable results. It is an excellent alternative to angiography, avoiding risks inherent to invasive methods and therefore contributing to animal welfare.

Histological study of right ventricle-pulmonary artery valved conduit implantation (RPVC) in dogs with pulmonic stenosis.

We examined whether right ventricle-pulmonary artery valved conduit (RPVC) implantation can overcome the disadvantages of current procedures for pulmonic stenosis (PS). We histologically evaluated the feasibility of RPVC using a homograft in PS model dogs. Eight dogs underwent pulmonary artery banding (PAB) and then 12 weeks later were assigned to PAB (n=4) or PAB+RPVC (n=4) groups. Dogs in the PAB group received no treatment throughout the experimental period, whereas the PAB+RPVC group underwent RPVC. At 1 year after PAB, hearts and conduits were explanted from euthanized dogs and histologically evaluated. The ratios (%) of myocardial fibrosis on right ventricle (RV) epicardial, median and endocardial layers were significantly lower in the PAB+RPVC, than in the PAB group. The ratio of myocardial fibrosis on left ventricular (LV) epicardial and endocardial layers were significantly lower in the PAB+RPVC, than in the PAB group. Neo-intimal thickness in the anastomosis areas of the Denacol and PAB+RPVC groups was 42.77 +/- 30.19 and 88.30 +/- 27.24 microm, respectively, with no significant differences between the groups. Calcification and neo- intima hypertrophy were not obvious in the valve area. Immunohistological staining showed that the internal surface of the anastomosis and intermediate areas were positive for endothelial cells. We concluded that RPVC using a bioprosthetic graft can apparently overcome the disadvantages of current procedures for pulmonic stenosis.

Cardiovascular effects of right ventricle-pulmonary artery valved conduit implantation in experimental pulmonic stenosis.

Right ventricle (RV)-pulmonary artery (PA) valved conduit (RPVC) implantation decreases RV systolic pressure in pulmonic stenosis (PS) by forming a bypass route between the RV and the PA. The present study evaluates valved conduits derived from canine aortae in a canine model of PS produced by pulmonary artery banding (PAB). Pulmonary stenosis was elicited using PAB in 10 conditioned beagles aged 8 months. Twelve weeks after PAB, the dogs were assigned to one group that did not undergo surgical intervention and another that underwent RPVC using denacol-treated canine aortic valved grafts (PAB+RPVC). Twelve weeks later, the rate of change in the RV-PA systolic pressure gradient was significantly decreased in the PAB+RPVC, compared with the PAB group (60.5 +/- 16.7% vs. 108.9 +/- 22.9%; p<0.01). In addition, the end-diastolic RV free wall thickness (RVFWd) was significantly reduced in the PAB+RPVC, compared with the PAB group (8.2 +/- 0.2 vs. 9.4 +/- 0.7 mm; p<0.05). Thereafter, regurgitation was not evident beyond the conduit valve and the decrease in RV pressure overload induced by RPVC was confirmed. The present results indicate that RPVC can be performed under a beating heart without cardiopulmonary bypass and adapted to dogs with various types of PS, including "supra valvular" PS or PS accompanied by dysplasia of the pulmonary valve. Therefore, we consider that this method is useful for treating PS in small animals.

Percutaneous transcatheter coil embolization of a ventricular septal defect in a dog.

A 4-month-old male French Bulldog weighing 5.0 kg (11 lb) was referred for a heart murmur. A grade 3/6 systolic murmur was detected at the left heart base and a grade 4/6 systolic murmur was detected at the right heart base. By use of color-flow Doppler ultrasonography and cardiac catheterization, a diagnosis of supracristal ventricular septal defect (VSD) with accompanying aortic regurgitation was made. Percutaneous transcatheter coil embolization was used to close the VSD. Because residual shunt was detected via echocardiography after coil implantation, the residual shunt was followed periodically via echocardiography to detect spontaneous closure of the VSD. Volume overload in the left ventricle was detected in the dog 131 days after admission. Additional coils were placed 137 days after admission. Hemolysis resulting in hemoglobinuria was detected, but this complication was mild. In the dog of this report, results of coil occlusion for correction of VSD were promising. Thus, coil occlusion should be considered as an alternative treatment for VSD in dogs.

Use of a jugular vein autograft for reconstruction of the cranial vena cava in a dog with invasive thymoma and cranial vena cava syndrome.

A spayed female dog was evaluated because of edema of the ventral cervical region, lethargy, cough, and reduced exercise tolerance. Invasive thymoma and cranial vena cava syndrome were diagnosed by use of ultrasound-guided fine-needle biopsy and contrast-enhanced helical computed tomography. Resection of the cranial vena cava and an autogenous jugular vein graft were used for restoration of normal venous return to the right atrium and alleviation of the cranial vena cava syndrome.

Liver blood perfusion as a possible instrument for fetal growth regulation.

Placental and fetal liver blood perfusions are reduced in intrauterine growth-restricted human fetuses. We hypothesized that changes in fetal liver blood supply can alter fetal growth. In nine ewes with twin pregnancies at a gestational age of 119+/-2 days, a stent (4 mm) was placed into the ductus venosus of one twin (DV(stent) group). Alternatively, in 17 near term sheep with twin (n=11) or singleton (n=6) pregnancies, a DV was blocked with an embolization coil (DV(coil) group) for about one week. The cell proliferation rate (pKi-67) was determined in the liver, heart, skeletal muscle, kidneys and placenta. The dilatation or occlusion of the DV did not change placental perfusion on the first day or later after surgery. The liver blood supply was decreased in the DV(stent) group by more than half from 499+/-371 to 278+/-219 ml min(-1) (mean+/-s.d., n=4), and increased two-fold in the DV(coil) group (P< 0.05). The percentage of liver/body weight was decreased from 3.9+/-0.6 per cent in control twin to 3.0+/-0.2 per cent (n=3) in the DV(stent) group. Occlusion of the DV lead to an increase in the percentage of liver/body weight from 3.4+/-0.8 per cent to 4.3+/-0.8 per cent (n=11, P< 0.05). Reduced liver blood supply in the DV(stent) group was associated with a decrease of cell proliferation in the liver from 12.43+/-2.31 to 6.5+/-0.62 (nuclei microm(2) 10(-4), n=3, P=0.058), in heart from 1.14+/-0.03 to 0.93+/-0.02 (nuclei microm(2) 10(-4), P< 0.05), and in skeletal muscle from 0.82+/-0.05 to 0.54+/-0.01 (nuclei microm(2) 10(-4), P< 0.05). The increased liver blood perfusion following occlusion of the DV increased cell proliferation sixfold in the liver, (n=9, P< 0.005) and twofold in heart muscle, skeletal muscle and the kidneys (P< 0.05), whereas no significant difference was seen in the placenta. The expression of mRNA for IGF-I and IGF-II in the liver was increased in the DV(coil) group. In conclusion, these results suggest that liver blood perfusion can regulate fetal growth.

Permanent implantation of a reinforced polytetrafluoroethylene vascular graft for treatment of artificial defects of the teat cistern mucosa in cows.

OBJECTIVE: To evaluate use of a reinforced polytetrafluoroethylene vascular graft for treatment of an artificial defect of mucosa of the teat cistern in lactating cows. DESIGN: Prospective study. ANIMALS: 9 clinically normal lactating dairy cows. PROCEDURE: A 20-mm wide circumferential area of mucosa was sharply excised from the cistern of 1 teat on each cow 10 days after spontaneous calving, and the lesion was covered by a graft. After 14 days of passive milk drainage, routine milking was resumed. Follow-up examinations were performed during the next 2 lactation periods and included evaluation of wound healing, location and sonographic appearance of the implant, milk flow and yield, and somatic cell counts. Cows were slaughtered, and teats and mammary glands were examined microscopically. RESULTS: Implants had partially to totally collapsed within 30 to 90 days. Milk flow was significantly increased by day 15 of the first lactation, but decreased significantly by day 300 of lactation 1. At the end of lactation 1, milk flow had ceased in 3 out of 7 quarters. Only 3 of 9 quarters drained through grafted teats were milkable at the end of the study. Somatic cell counts of these quarters were significantly increased in the first lactation period. At necropsy, 2 grafts were in the teat cistern, but only 1 was incorporated into the mucosa by connective tissue. The mucosa was thickened in all teats with grafts, and there was epithelial metaplasia and granulation tissue proliferation. CLINICAL RELEVANCE: Use of a polytetrafluoroethylene graft can preserve patency in the first lactation period. However, the graft may not be sufficiently incorporated into the mucosa if routine machine milking is resumed 2 weeks after implantation. )

[Surgical treatment of an obliterating thrombosis of the jugular vein in a horse. Use of synthetic vessel prosthesis]. / Chirurgische behandeling van een oblitererende trombose van de vena jugularis van een paard. Gebruik van een synthetische vaatprothese.

A 6-year-old trotter gelding presented with exercise intolerance and swelling of the left side of the head during exercise and grazing. The complaints were caused by a complete thrombosis of the left jugular vein. In this case report a surgical approach is described in which a bypass was created with a synthetic vascular graft. After treatment the horse was capable of racing at his former level. The patency of the synthetic graft was 11 months.