Biomedical subjects

M Lachat

Publications and source records attributed to M Lachat.

At least 55 records · Page 3Linked to original sources

PubMed1997

New approach to patency and flow assessment after left internal thoracic artery hypoperfusion syndrome with additional saphenous vein graft to the left anterior descending artery with phase-contrast magnetic resonance angiography.

OBJECTIVE: Perioperative and early postoperative flow reduction of a left internal thoracic artery conduit is a rare complication of myocardial revascularization and may lead to the potentially fatal left internal thoracic artery hypoperfusion syndrome. It has been advocated that an additional vein graft be placed to the distal left anterior descending artery to provide sufficient myocardial perfusion. Some evidence exists, however, that this high-flow vein might lead to competing or even backward flow through the internal thoracic artery. METHODS: In the past 2 years, 21 patients received an additional vein graft to the distal left anterior descending artery for left internal thoracic artery hypoperfusion syndrome. Nineteen of these patients were available for magnetic resonance imaging. Early (< 6 months) and late (> 12 months) postoperative flow measurements, both in the left internal thoracic artery and in the saphenous vein grafts, were performed by means of conventional and a segmented k-space phase-contrast magnetic resonance angiography technique. RESULTS: Early magnetic resonance examinations indicated that all conduits had adapted to the coronary flow type with predominant diastolic perfusion. Patency rate both at the early and at the late study was 100%. No concurrent flow, flow reversal, or steal phenomena were observed. Mean flow rates were 49.2 ml/min for the left internal thoracic artery and 72.6 ml/min for the saphenous vein graft. CONCLUSION: On the basis of the flow data obtained with magnetic resonance angiography, the use of an additional saphenous vein graft as the treatment of choice in left internal thoracic artery hypoperfusion syndrome does not lead to occlusion of the artery. Conduit flow adaptation to the diastolic predominance occurs in the first 6 months after operation.

Coronary Vessels↗

PubMed1997

Congenital aortopulumonary window: diagnosis, surgical technique and long-term results.

OBJECTIVE: Congenital aortopulmonary window is rare, often associated with other cardiac anomalies. Surgical repair as the only treatment should be performed before pulmonary vascular changes have developed. This study presents the long-term outcome after surgical correction for this condition. MATERIALS AND METHODS: Between 1971 and 1993, 13 patients with congenital aortopulmonary window were found. 10 had type I, 2 type II and 1 had type III. Concomitant cardiac anomalies were present in 10/13. Eleven patients were operated on at a mean age of 31.2 +/- 48.3 months (range 6 days-10 years). Thoracotomy was used in 3 and sternotomy in 9 patients. In 4/11, the aorto-pulmonary window was simply ligated, 4 had a transpulmonary approach and 1 combined with a transaortic approach. The aortopulmonary window was closed directly in 2 and with a Dacron patch in 1. Cardiopulmonary bypass was used in 6 patients. Associated anomalies in 10/11 patients. RESULTS: There was one operative death (9%): a six-day old boy with interrupted aortic arch died 6 h postoperatively due to low-cardiac output. The mean follow-up period is 8.1 +/- 7.3 years (range 2-24 years). Clinical examination, transaortic echocardiography and/or cardiac catheterization were obtained in the follow-up. There was no late death. All are in New York Heart Association (NYHA) class I. One had to be reoperated on for a recurrent shunt 29 months after ligation and one had angioplasty after 23 months for residual stenosis of the reimplanted right pulmonary artery. The actuarial survival rate is 90% after 1, 5 and 10 years. CONCLUSIONS: The surgical treatment of aortopulmonary window has a low risk, even if associated with major cardiac anomalies. Prompt operative treatment achieves excellent long-term results.

Actuarial Analysis↗

PubMed1997

Aortobronchial and aortoesophageal fistulae as risk factors in surgery of descending thoracic aortic aneurysms.

OBJECTIVE: Assess outcome of patients with descending thoracic aortic aneurysms complicated by aortobronchial and aortoesophageal fistulae in comparison to patients undergoing repair of aortic aneurysms without fistulae. METHODS: In a consecutive series of 145 patients (age 60 +/- 12 years) with repair of descending thoracic and thoracoabdominal aortic aneurysms, 11 patients (8%; age 63 +/- 9; NS) primarily presented for hematemesis and/or hemoptysis. In 8/11 patients (73%) an aortobronchial fistula was identified, and 3/11 patients (27%) suffered from an aortoesophageal fistula. Five of 11 patients (45%) had undergone previous aortic surgery in the same region. RESULTS: Extent of aortic segments (range 1-8) replaced was 3.1 +/- 1.4 for all versus 2.6 +/- 0.9 for fistulae (NS). Aortic cross clamp time was 38 +/- 22 min for all versus 45 +/- 15 min for fistulae (NS). Mortality at 30 days was 18/145 (12%) for all versus 16/134 (12%) without fistulae versus 2/11 (18%) with fistulae (NS). Paraparesis and or paraplegia was observed in 11/145 (8%) for all versus 10/134 (7%) without fistulae versus 1/11 (9%) for cases with fistulae (NS). Nine additional patients died after hospital discharge, seven without fistulae and two with fistulae (days 80, and 120) bringing the 1-year mortality up to 23/134 (17%) without fistulae versus 4/11 (36%) with fistulae (NS). Further analysis shows that the 1-year mortality accounts for 1/8 patients (13%) with aorto-bronchial fistulae versus to 3/3 patients (100%) with aorto-esophageal fistulae (esophageal versus bronchial fistula: P = 0.018; esophageal versus no fistula: P = 0.006). CONCLUSIONS: Outcome of patients suffering from descending thoracic aortic aneurysms complicated by aorto-bronchial fistulae can be similar to that without fistulae, whereas for cases complicated by aorto-esophageal fistulae the prognosis seems to remain poor even after successful hospital discharge.

Aged↗

PubMed1997

Ivemark syndrome. A case with successful surgical intervention.

A 19-day-old boy with Ivemark syndrome (splenic agenesis associated with complex cardiac malformations and visceral abnormality) underwent palliative surgery including Glenn and hemi-Fontan procedures. Five months later the child is alive and well. We believe that early palliative surgery is worthwhile in Ivemark syndrome with a single ventricle.

Abnormalities, Multiple↗

PubMed1996

Kartagener's syndrome: clinical presentation and cardiosurgical aspects.

BACKGROUND: Long-term observations in patients with Kartagener's syndrome (situs inversus, bronchiectasis, and sinusitis) are rare. The role of additional cardiac malformations and their surgical repair is not well known. METHODS: Nine patients (5 female and 4 male) with Kartagener's syndrome were identified and followed. Four patients had associated cardiac anomalies; 4 underwent total surgical repair at the ages of 4 (2 patients), 7, and 34 years. RESULTS: The postoperative period was uneventful, and these 4 patients are doing well 7 months and 2, 9, and 19 years after repair. The other patients are being treated with conservative therapy and are in relatively good condition. CONCLUSIONS: This disease can be temporarily benign when treated with antibiotics and physiotherapy. Associated cardiac anomalies seem to be quite common, and such patients need careful cardiologic follow-up. Surgical intervention can be safely performed in patients suffering from Kartagener's syndrome associated with a congenital cardiac malformation and produces good long-term results. Bilateral lung transplantation seems to be the therapy of choice in patients with respiratory insufficiency but without concomitant cardiac anomalies.

Aftercare↗

PubMed1996

Improved growth with bioabsorbable sutures in both high- and low-pressure zones.

BACKGROUND: Compromised growth after operation remains a significant problem in the cardiovascular field. Some benefit of absorbable suture materials has been demonstrated for arterial anastomoses. However, for the low-pressure zone, few data are available. METHODS: To assess growth in high- versus low-pressure zones we transected the abdominal aorta (high-pressure zone) as well as the inferior vena cava (low-pressure zone) in 10 young mongrel dogs using for reanastomosis 7-0 nonabsorbable versus absorbable running sutures in random order. RESULTS: All animals survived and were evaluated over 12 months including body weight (gain, 212% +/- 45% for nonabsorbable versus 218% +/- 8% for absorbable; not significant), angiography, and, after elective sacrifice, detailed studies of aorta and vena cava. Systematic complication of angiographic data at 12 months showed at the suture level an area of 13.8 mm2 for nonabsorbable versus 24.3 +/- 14.4 mm2 for absorbable sutures in the high-pressure zone as compared with 12.9 +/- 4.9 mm2 for nonabsorbable versus 25.3 +/- 15.4 mm2 for absorbable sutures in the low-pressure zone. Residual lumen, calculated as a function of the area above and below the suture, accounted for 35% +/- 10% for nonabsorbable versus 92% +/- 12% for absorbable sutures (p < 0.001) in the high-pressure zone as compared with 37% +/- 13% for nonabsorbable versus 75% +/- 15% for absorbable sutures (p < 0.003) in the low-pressure zone (high versus low, not significant). Poststenotic dilatation accounted for 199% +/- 22% for nonabsorbable versus 126% +/- 43% for absorbable sutures (p < 0.01) in the high-pressure zone. In the low-pressure zone, poststenotic dilatation remained below the inflow area, and the residual poststenotic lumen accounted for 52% +/- 14% for nonabsorbable versus 77% +/- 16% for absorbable sutures (p < 0.004). Macroscopic, light, and scanning electron microscopic studies confirmed different growth patterns in high- versus low-pressure zones. CONCLUSIONS: Aortic narrowing resulted in poststenotic dilatation and unrestricted outflow path (hourglass-type stenosis). Caval narrowing was followed by restriction of poststenotic outflow path (funnel-type stenosis). Absorbable suture material allows for superior growth in both high- and low-pressure zones.

Absorption↗

PubMed1996

Eradication of aortic infections with the use of cryopreserved arterial homografts.

BACKGROUND: The surgical treatment of vascular infection is associated with a substantial early and late mortality. Cryopreserved homografts were evaluated for in situ reconstruction in aortic infections. METHODS: Between January 1991 and July 1995, homografts were used in 19 patients (mean age, 61 +/- 13 years; range, 40-85 years) with mycotic aneurysms (9/19; 47%) or infected grafts (10/19; 53%) in the thoracic (7/19; 37%) or abdominal (12/19; 63%) aorta. Sepsis was present preoperatively in 14 of 19 (74%) patients, and 18 of 19 (95%) had received antibiotic treatment for 6.4 +/- 6 months (range, 1-36 months). Up to ten previous vascular procedures had been done in 11 of 19 patients (58%). RESULTS: There was one (5.2%) early and two (11%) late deaths, with one (5.5%) of the late deaths being homograft related. The mean hospital stay was 27 +/- 26 days (range, 7-84 days). Antibiotics were given postoperatively for 30 +/- 12 days (range, 4-84 days). During the follow-up period of 18.6 +/- 13 months (range, 7-60 months), there were no instances of reinfection, suture line rupture, homograft stenosis, or anastomotic aneurysms. CONCLUSIONS: Cryopreserved arterial homografts allow safe in situ reconstruction, decrease early and midterm mortality, and reduce antibiotic requirements. Early and midterm reoperations are unnecessary.

Adult↗

PubMed1996

Aortic valve preservation in acute type A dissection: is it sound?

A series of 200 consecutive patients with acute Stanford type A dissection (157 men, 78%; 43 women, 22%) was analyzed to assess the validity of aortic valve preservation or repair. Indication for the operation in most cases was based on echocardiographic examination alone, to reduce the delay. In the majority of patients (111/200, 56%) the aortic valve was preserved or repaired if necessary. Aortic root replacement with a composite graft was performed in 66 of 200 patients (33%), mainly because of an enlarged aortic anulus and sinus. Replacement of the aortic valve and the supracoronary ascending aorta was performed in 23 of 200 patients (12%) with a diseased aortic valve (e.g., bicuspid valve) but an acceptable aortic sinus. Follow-up totaled 656 patient-years (maximum 14 years). Actuarial analyses as a function of type of repair and type of aortic valve provided the following probabilities plus or minus errors (95%): overall survival of the 200 patients was 78.3% +/- 2.9% after 30 days, 74.95% +/- 3.1% after 1 year, 67.9% +/- 3.6% after 5 years, and 48.5% +/- 6.1% after 10 years. Actuarial probability of freedom from reoperation for valve failure in the complete series was calculated as 100.0% +/- 0.0% after 30 days, 99.3% +/- 0.7% after 1 year, 97.5% +/- 1.5% after 5 years, and 95.1% +/- 2.8% after 10 years. During long-term follow-up, there was no significant difference among groups with regard to structural deterioration, valve thrombosis, thromboembolic complications, anticoagulant-induced hemorrhage, and endocarditis. Freedom from valve failure and valve-related complications are similar for preserved, repaired, mechanical, and biologic valves. Valve-related reoperations are rare during at least 5 years of follow-up. Hence preservation or repair of the aortic valve can be recommended in the majority of patients with acute type A dissection.

Actuarial Analysis↗

PubMed1996

Endothelial cell seeding improves patency of synthetic vascular grafts: manual versus automatized method.

Lack of an endothelial surface is the most important variable causing the relatively poor patency of synthetic bypass grafts. This study was designed to investigate the effect of endothelial cell seeding on small-diameter Dacron grafts seeded with microvascular endothelial cells from omentum, and to evaluate two methods (manual vs automatized) for one-stage seeding in a canine carotid artery model. In 30 mongrel dogs microvascular endothelial cells were harvested from omentum, either by a manual or an automatized method, and seeded onto 6-mm internal diameter Dacron prostheses prior to the graft interposition into the common carotid arteries. Non-seeded Dacron grafts were used as control grafts. All dogs received dipyridamole (75 mg/day) and acetylsalicylic acid (325 mg/day) for 4 weeks. The prostheses were explanted between 2 and 26 weeks after insertion. The results were assessed by patency, angiography, light and scanning electron microscopy, transmission electron microscopy, and morphometry. Endothelial cell seeding improved the patency rate significantly, regardless of the seeding methods used. The overall actuarial patency rates at 5, 12, and 26 weeks were 98%, 94% and 94%, respectively, for the seeded Dacron grafts, and 92%, 62% and 54%, respectively, for the non-seeded grafts. The automatized method yielded more endothelial cells per gram of omental tissue than the manual method (P = 0.0002), but there was no difference (P = 0.34) between the seeding densities per square centimeter of the graft surface. The harvesting and seeding by the automatized method took 55 min for the whole procedure, 20 min less than the manual method. We concluded that one-stage endothelial cell seeding with omental microvascular endothelial cells improved the patency of small-diameter Dacron grafts in a canine model. The automatized method obtained excellent results comparable to the manual procedure, and also reduced the time necessary for the cell seeding.

Animals↗

PubMed1996

Surgery for ruptured thoracic and thoraco-abdominal aortic aneurysms.

OBJECTIVE: To assess the outcome of patients with ruptured descending thoracic and thoracoabdominal aortic aneurysms undergoing emergency repair, in comparison to elective surgery for chronic lesions. METHODS: A prospective study of 100 consecutive patients operated upon the descending aorta (1-8 segments) using proximal unloading and distal protection with partial cardiopulmonary bypass, heparin surface-coated perfusion equipment and low systemic heparinization (loading dose 100 IU/kg, activated coagulation time > 180 s), staged cross-clamping, sealed grafts and graft inclusion. RESULTS: Arteriosclerotic lesions were present in 53/100 patients (53%) for all, 30/53 (56%) for chronic, and 21/33 (63%) for ruptured, aneurysms (NS). Dissecting lesions were found in 38/100 patients (38%) for all, 20/53 (38%) for chronic, and 8/33 (24%) for ruptured aneurysms (NS). Preoperative hematocrit was 38 +/- 6% for all, 40 +/- 5% for chronic, and 33 +/- 5% for ruptured aneurysmal patients (P < 0.001 ruptured versus chronic). The extent of aortic repair (1-8 segments) was 3.3 +/- 1.6 for all, 3.5 +/- 1.5 for chronic, and 3.2 +/- 1.4 for ruptured, aneurysms (NS). Transdiaphragmatic repair was performed in 51/100 (51%) of all, 28/53 (53%) of chronic, and 17/33 (51%) of ruptured aneurysms (NS). Aortic cross-clamp time was 38 +/- 21 min for all, 39 +/- 24 min for chronic, and 38 +/- 17 min for ruptured, aneurysmal patients (NS). The amount of red cells washed and autotransfused was 2792 +/- 2239 ml in all, 3143 +/- 2531 ml in chronic, and 2074 +/- 1350 ml in ruptured, aneurysmal patients (P < 0.025). The amount of packed red cells required was 2181 +/- 1830 ml for all, 1736 +/- 1333 ml for chronic, and 2947 +/- 2395 ml for ruptured aneurysmal patients (P < 0.010). Thirty-day mortality was 9/100 (9%) for all, 3/53 (6%) for chronic, and 5/33 (15%) for ruptured aneurysmal patients (NS). Parapareses/plegias occurred in 9/100 (9%) of all, 6/53 (11%) of chronic, and 3/33 (9%) of ruptured, aneurysmal patients (NS). Stepwise regression analysis identified aortic cross-clamp time as a predictor of early mortality (P = 0.002) and parapareses and paraplegias (P = 0.001). Age (P = 0.001), extent of repair (P = 0.008) and preoperative hematocrit (P = 0.001) were predictors for homologous transfusion requirements. CONCLUSION: Emergency repair of ruptured descending thoracic and thoracoabdominal aortic aneurysms can be achieved with acceptable results.

Aortic Dissection↗

PubMed1996

Long-term function of vascular access for hemodialysis.

OBJECTIVES: To compare the outcome of autogenous arteriovenous fistulas (AVF) with interposition graft fistulas for hemodialysis access. DESIGN: Retrospective clinical study. SETTING: Department of Surgery, Zurich University Hospital. METHODS: Primary and secondary patency rates were calculated by life tables. Factors potentially affecting patency were studied by comparison of life tables using the log rank test. MAIN RESULTS: From 1980 to 1992, 414 patients were operated on for long-term vascular access. 720 fistulas were created including 429 AVF and 291 interposition grafts (150 bovine xenografts, 69 PTFE grafts, 59 sheep collagen grafts, 10 autologous and 1 homologous vein grafts). Secondary patency rates after 1 and 3 yr were 74/64% in AVF, 56/24% in bovine xenografts, 58/40% in PTFE grafts and 71/45% in sheep collagen grafts. The latter performed not significantly worse than AVF. Primary and secondary patency rates were significantly lower in women.

Adolescent↗

PubMed1995

Seeding with omental cells prevents late neointimal hyperplasia in small-diameter Dacron grafts.

BACKGROUND: The influence of complete endothelialization of a prosthetic graft on development of late neointimal hyperplasia is unknown. This study was designed to investigate the effect of complete coverage with endothelial-like cells on late neointimal hyperplasia in small-diameter Dacron grafts seeded with omental cells in a canine model. METHODS AND RESULTS: Four-mm-ID Dacron grafts were seeded with cells from omentum and implanted in the carotid arteries in 24 mongrel dogs. Each dog received one seeded and one nonseeded graft. The graft patencies were assessed by angiography at 1, 5, 12, 26, and 52 weeks after surgery. The prostheses were explanted at 5, 12, 26, and 52 weeks after surgery and underwent microscopic studies. The actuarial patency rates at 1, 5, 12, 26, and 52 weeks were 100%, 95%, 95%, 95% and 95% for seeded grafts and 100%, 86%, 49%, 40%, and 13% for nonseeded grafts, respectively. The seeded grafts exhibited a uniform endothelial-like luminal monolayer without the development of late neointimal proliferation or anastomotic neointimal hyperplasia. Neointimal tissue thickness increased up to 6 months; no additional progression of the subendothelial tissue thickness was observed, in fact there was an insignificant decrease. CONCLUSIONS: Seeding with omental cells prevents development of late neointimal hyperplasia of small diameter prosthetic vascular grafts in a canine model.

Animals↗

PubMed1994

Superior late patency of small-diameter Dacron grafts seeded with omental microvascular cells: an experimental study.

The purpose of the study was to investigate the effect of omental microvascular cell seeding on the patency of small-diameter Dacron prostheses usable for coronary artery bypass grafting. In a canine carotid artery model, each dog (n = 64) received one seeded and one similar nonseeded Dacron prosthesis (internal diameter = 4 or 6 mm). Enzymatically harvested omental microvascular cells (omentum = 27.6 +/- 5.9 g [+/- the standard deviation]; range, 17 to 50 g) were seeded prior to implantation. The seeding density was 1.91 +/- 0.26 [+/- the standard error] x 10(6) cells/cm2 of graft surface. Dipyridamole (75 mg/d) and acetylsalicylic acid (325 mg/d) were administered orally for 4 weeks postoperatively. The prostheses were explanted between 2 and 52 weeks after placement. The results were assessed by angiography; light, scanning electron, and transmission electron microscopy; and morphometry. The seeded grafts developed a uniform luminal monolayer of endothelial cells with minimal platelet or cellular deposition. These grafts also had a significantly higher overall patency rate and significantly larger thrombus-free surface areas than the nonseeded grafts. The overall actuarial patency rates at 1 week, 5, 12, 26, and 52 weeks were 100%, 98%, 93%, 93%, and 93%, respectively, for seeded Dacron grafts and 100%, 91%, 61%, 54%, and 18%, respectively, for nonseeded grafts. The patency rates of Dacron grafts usable for coronary artery bypass grafting are significantly improved by seeding with omental microvascular cells in a canine model.

Actuarial Analysis↗

PubMed1994

[Do resorbable suture materials permit safe vascular anastomoses?].

Vascular surgery in growing organisms is still problematic. Especially in surgical therapy of coarctation of the aorta, high restenose rates are documented if non-absorbable polypropylene and running suture technique ist used. Theoretically, absorbable suture material allows a running suture technique with less restenose rates. Our study compares absorbable (polyglyconat and polydioxanon) with non-absorbable (polypropylene) suture material for repair of aorta in growing dogs. Anastomoses performed with absorbable suture material show after one year very good functional results without any local complications. In conclusion we can say that absorbable suture material allows formation of safety vascular anastomoses and doesn't impair growth of anastomoses.

Age Factors↗

PubMed1993

[Hemodynamic effects of the implantation of an intracaval oxygenator].

Treatment of severe respiratory failure by extracorporeal membrane oxygenation (ECMO) is complex. However, there is now an intravascular gas exchanger (IVOX) available that provides extrapulmonary gas transfer without requiring an extracorporeal blood path. The present study was performed to determine the hemodynamic effects resulting from the intracaval placement of the intravascular device. A bovine model (n = 6; body-weight = 72 +/- 5 kg) was selected for temporary lung support with the intravascular device. The latter was placed in the caval axis under fluoroscopic control after full instrumentation of the animal for hemodynamic measurements including a pulmonary artery catheter for determination of cardiac output by thermodilution and continuous readout of mixed venous oxygen saturation. All measurements were taken after a stabilization period of 15 min. The heart rate moved from 65 +/- 8 before to 72 +/- 10 after implantation and 68 +/- 9 after onset of intravascular gas exchange (NS). Right atrial pressure was 13 +/- 3 mm Hg before, 12 +/- 3 mm Hg after implantation and 10 +/- 3 mm Hg after onset (NS) whereas femoral venous pressure moved from 14 +/- 3 mm Hg to 17 +/- 4 mm Hg (p < 0.05) and remained at 17 +/- 4 mm Hg after onset. Cardiac output was 5.3 +/- 0.7 l/min before, 5.4 +/- 0.7 l/min after implantation and 5.3 +/- 1.1 l/min after onset (NS) while mixed venous oxygen saturation dropped from 60 +/- 7% to 54 +/- 11% and moved to 57 +/- 11 after onset of the device (NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Immediate shear stress resistance of endothelial cell monolayers seeded in vitro on fibrin glue-coated ePTFE prostheses.

The shear stress resistance of endothelial cells (EC) previously seeded onto ePTFE grafts was assessed by morphometric determination of the number of cells per cm2 of graft surface before and after exposure of 6 h of arterial blood flow interposed in the canine femoral artery. Autologous venous endothelial cells (AVEC) were harvested from the extrajugular veins of five dogs. The AVEC were cultured in vitro and seeded at a density of 150 x 10(3) cells per cm2 onto 4 mm ID ePTFE grafts precoated with fibrin glue and human fibronectin. Subsequently, the AVEC monolayers on the grafts were cultured for 8 days using a perfusion system and then implanted end-to-end in the femoral artery. All grafts remained patent (5/5). Scanning electron microscopy demonstrated complete, thrombus-free monolayers of AVEC after 6 h of arterial blood flow. The cell densities were 124 +/- 14 and 129 +/- 7 x 10(3) cells per cm2 respectively before and after implantation. It is concluded that in vitro lining of 4 mm ePTFE vascular prostheses is feasible and results in EC monolayers on the graft surface which are shear stress resistant and athrombogenic.

Animals↗

PubMed1993

[Long-term results in the dog carotid artery with small lumen vascular prostheses with microvascular endothelial cells].

In this study we evaluated the long-term results of microvascular endothelial cell seeding of small diameter Dacron grafts with omentally derived cells in a canine model. 6 cm long and 4 mm I.D. seeded Dacron prostheses were implanted end-to-end in the carotid position in 12 dogs for 6 to 12 months. Microvascular endothelial cells were enzymatically harvested from omentum prior to implantation and seeded onto Dacron grafts with a seeding density of 1.5 x 10(6) cells/cm2 of the graft. The antiplatelet therapy (Aspirin, Dipyridamol) was administered for 4 weeks postoperatively. All seeded grafts were patent throughout the study. The thrombus-free surface area for seeded grafts was 99.6 +/- 0.8% and 99.6 +/- 0.9% at 6 months and one year, respectively. Scanning electron microscopy revealed a confluent endothelial layer. We concluded that endothelial cell seeding of smaller-diameter prosthetic vascular grafts with omentally derived endothelial cells obtained excellent long-term patency rate in the canine model.

Animals↗

PubMed1993

Long-term results of tissue development and cell differentiation on Dacron prostheses seeded with microvascular cells in dogs.

PURPOSE: The purpose of this study was to investigate in vivo the long-term development, differentiation, and proliferation of the subendothelial tissue on Dacron prostheses seeded with microvascular cells (MVC). METHODS: Autologous MVC from omental adipose tissue were seeded on 4 mm Dacron prostheses and the prostheses interposed in the carotid arteries of mongrel dogs for 5, 13, and 26 weeks. RESULTS: Light and electron microscopic evaluation of patent seeded prostheses demonstrated an almost complete monolayer of endothelial cells and well-organized subendothelial tissue, whereas patent control prostheses were mainly covered by red and white thrombi, which were partially replaced by organized tissue with increased implantation time. The measurements of the thickness of the luminal cell layer in seeded and control grafts showed no statistically significant increase between 5 and 26 weeks of implantation. The subendothelial tissue of seeded prostheses demonstrated a time-dependent maturation of highly synthesizing myofibroblasts embedded in a collagen matrix to cells with features of smooth muscle cells located in a collagen-elastin matrix. In control grafts examined after 26 weeks the spontaneous endothelialization was accompanied by a delayed or incomplete maturation of subendothelial tissue. CONCLUSIONS: Our study indicates that MVC seeded onto Dacron prostheses are able to generate a vascular wall that does not continue to proliferate after prolonged implantation and that increasingly resembles the wall of a normal artery in cell differentiation and intercellular matrix.

Animals↗