Modeling Endoleaks and Collateral Reperfusion following Endovascular AAA Exclusion

2003 ◽  
Vol 10 (3) ◽  
pp. 424-432 ◽  
Author(s):  
Chuh K. Chong ◽  
Thien V. How ◽  
Geoffrey L. Gilling-Smith ◽  
Peter L. Harris
Keyword(s):  
Stent Graft ◽  
Aortic Pressure ◽  
Type I ◽  
Type Ii ◽  
Pump System ◽  
Type Ii Endoleak ◽  
Type I Endoleak ◽  
The Impact ◽  
Mean Aortic Pressure

Purpose: To investigate the effect on intrasac pressure of stent-graft deployment within a life-size silicone rubber model of an abdominal aortic aneurysm (AAA) maintained under physiological conditions of pressure and flow. Methods: A commercial bifurcated device with the polyester fabric preclotted with gelatin was deployed in the AAA model. A pump system generated physiological flow. Mean and pulse aortic and intrasac pressures were measured simultaneously using pressure transducers. To simulate a type I endoleak, plastic tubing was placed between the aortic wall and the stent-graft at the proximal anchoring site. Type II endoleak was simulated by means of side branches with set inflow and outflow pressures and perfusion rates. Type IV endoleak was replicated by removal of gelatin from the graft fabric. Results: With no endoleak, the coated graft reduced the mean and pulse sac pressures to negligible values. When a type I endoleak was present, mean sac pressure reached a value similar to mean aortic pressure. When net flow through the sac due to a type II endoleak was present, mean sac pressure was a function of the inlet pressure, while pulse pressure in the sac was dependent on both inlet and outlet pressures. As perfusion rates increased, both mean and pulse sac pressures decreased. When there was no outflow, mean sac pressure was similar to mean aortic pressure. In the presence of both type I and type II endoleaks, mean sac pressure reached mean aortic pressure when the net perfusion rate was low. Conclusions: In vitro studies are useful in gaining an understanding of the impact of different types of endoleaks, in isolation and in combination, on intrasac pressure after aortic stent-graft deployment.

Distribution of Sac Pressure in an Experimental Aneurysm Model after Endovascular Repair: The Effect of Endoleak Types I and II

2003 ◽  
Vol 10 (3) ◽  
pp. 516-523 ◽  
Author(s):  
Eleftherios S. Xenos ◽  
Scott L. Stevens ◽  
Michael B. Freeman ◽  
John P. Pacanowski ◽  
David C. Cassada ◽  
...  
Keyword(s):  
Type I ◽  
Type Ii ◽  
Experimental Aneurysm ◽  
Pump System ◽  
Type Ii Endoleak ◽  
Proximal Neck ◽  
Aneurysm Wall ◽  
Type I Endoleak ◽  
Aneurysm Model ◽  
P Distribution

Purpose: To study in an experimental aneurysm model the differential distribution of strain/pressure (S/P) on the aneurysm wall before and after endograft exclusion and in the presence of individual type I and type II endoleaks. Methods: Two tapered elliptical Gore-Tex patches were sutured to an anterior and posterior longitudinal arteriotomy of an 8-mm Gore-Tex tube graft, thus creating a fusiform aneurysm. Two S/P transducers were placed at the proximal sac adjacent to the proximal neck, 2 at the site of the widest sac diameter, and 2 at the sac adjacent to the distal neck. The aneurysm, which was connected to a pulsatile pump system, was excluded using a 10-mm endograft. Type I and type II endoleaks were created and tested individually. S/P measurements were obtained at systemic systolic pressures (BP) of 80, 110, and 150 mmHg. Thrombosis of the sac contents was induced by injection of thrombin and calcium in the sac. Angiography was used to verify presence or absence of flow in the sac. Results: Aneurysm exclusion resulted in significant S/P reductions at all 3 BP levels versus prior to exclusion (p<0.05). Thrombus in the sac did not alter S/P in the excluded sac (p>0.05 for all 3 BP levels). In the presence of a proximal type I endoleak, S/P distribution was not uniform, and S/P at the proximal neck was close to S/P prior to exclusion (p>0.05 no graft versus type I endoleak for all 3 BP levels). This was also true in the presence of thrombus. With a type II endoleak, S/P was more evenly distributed and was not significantly elevated compared to the pressure without an endoleak (p>0.05, graft versus type II endoleak for all 3 BP levels). Thrombus had no effect on intrasac S/P with a type II endoleak. Intrasac S/P was significantly higher in the presence of a type I endoleak compared to a type II endoleak when BP=150 mmHg (p=0.008). Conclusions: Endovascular exclusion of an aneurysm results in uniform S/P reduction in the aneurysm sac. Type I endoleak, but not type II endoleak, results in significantly higher S/P in an area of the sac adjacent to the proximal neck. Thrombus does not result in significantly different S/P distribution in the aneurysm sac.

Noninvasive Diagnosis of Incomplete Endovascular Aneurysm Repair: D-Dimer Assay to Detect Type I Endoleaks and Nonshrinking Aneurysms

2002 ◽  
Vol 9 (1) ◽  
pp. 90-97 ◽  
Author(s):  
Francesco Serino ◽  
Damiano Abeni ◽  
Elisabetta Galvagni ◽  
Savino G. Sardella ◽  
Alberto Scuro ◽  
...  
Keyword(s):  
Thrombotic Event ◽  
Endovascular Aneurysm Repair ◽  
Test Group ◽  
Type I ◽  
Type Ii ◽  
Type Ii Endoleak ◽  
Blood Samples ◽  
Type I Endoleak ◽  
D Values ◽  
D Dimer

Purpose: To test the hypothesis that D-dimer (D-D), a cross-linked fibrin degradation product of an ongoing thrombotic event, could be a marker for incomplete aneurysm exclusion after endovascular abdominal aortic aneurysm (AAA) repair. Methods: In a multicenter study, 83 venous blood samples were collected from 74 AAA endograft patients and controls. Twenty subjects who were >6 months postimplantation and had evidence of an endoleak and/or an unmodified or increasing AAA sac diameter formed the test group. Controls were 10 nondiseased subjects >65 years old, 18 AAA surgical candidates, and 26 postoperative endograft patients with no endoleak and a shrinking aneurysm. Blood samples were analyzed for D-D through a latex turbidimetric immunoassay. The endograft patients were stratified into 5 clinical groups for analysis: no endoleak and decreasing sac diameter, no endoleak and increasing/unchanged sac diameter, type II endoleak and decreasing sac diameter, type II endoleak and increasing/unchanged sac diameter, and type I endoleak. Results: Individual D-D values were highly variable, but differences among clinical groups were statistically significant (p < 0.0001). D-D values did not vary significantly between patients with stable, untreated AAAs and age-matched controls (238 ± 180 ng/mL versus 421 ± 400 ng/mL, p > 0.05). Median D-D values increased at 4 days postoperatively (963 ng/mL versus 382 ng/mL, p > 0.05) and did not vary thereafter if there was no endoleak and the aneurysm sac decreased. D-D mean values were higher in patients with type I endoleak (1931 ± 924 ng/mL, p < 0.005) and those with unchanged/increasing sac diameters (1272 ± 728 ng/mL) than in cases with decreasing diameters (median 638 ± 238 ng/mL) despite the presence of endoleak (p < 0.0005). Conclusions: Elevated D-D may prove to be a useful marker for fixation problems after endovascular AAA repair and may help rule out type I endoleak, thus excluding patients from unnecessary invasive tests.

Assessment of a New Type I Endoleak Repair Technique Using an Anchoring Device

2013 ◽  
Vol 8 (4) ◽  
pp. 289-295
Author(s):  
Pham Minh Tuan ◽  
Hiroshi Ohtake ◽  
Seguchi Ryuta ◽  
Go Watanabe
Keyword(s):  
Stent Graft ◽  
Aortic Pressure ◽  
Type I ◽  
Repair Procedure ◽  
Life Threatening ◽  
Type I Endoleak ◽  
New Type ◽  
Descending Aortic Aneurysm ◽  
The Mean ◽  
Upper Rim

Objective Type I endoleaks are one of the most frequent and life-threatening complications of thoracic endovascular aortic repair. This study aimed to assess the use of suture-anchoring devices for repairing type I endoleaks. Methods The descending aortic aneurysm model (saccular type) was made by side-to-end anastomosis to a Dacron graft. A Matsui-Kitamura stent graft was deployed to create a proximal type I endoleak. Approximately 5 mm above the upper rim of the anastomosis, the aorta was punctured by the pistol of the suture-anchoring device with a T-shaped bar under fluoroscopy. Sutures were applied until angiography showed the absence of a type I endoleak. During the process, two pressure measurements were used to perform continuous assessments of aortic pressure and intra-aneurysm sac pressure. Results A mean ± SD of 5 ± 1 anchoring shots were used to eliminate type I endoleaks. The device performed well, and no complications were observed. The mean ± SD intrasac pressures before stent graft deployment, during endoleak maintenance, and after repair were 118 ± 5, 61 ± 4, and 26 ± 5 mm Hg, respectively. The postrepair pressure was significantly decreased ( P < 0.001; Student t test). Conclusions Despite some anatomic and clinical limitations identified during the experiments, the effectiveness of the suture-anchoring device was confirmed. Further improvement of the device will soon lead to its use as a less invasive endoleak repair procedure.

Homemade Fenestrated Stent-Grafts for Complete Endovascular Repair of Aortic Arch Dissections

2019 ◽  
Vol 26 (5) ◽  
pp. 645-651 ◽  
Author(s):  
Ludovic Canaud ◽  
Baris Ata Ozdemir ◽  
Lucien Chassin-Trubert ◽  
Julien Sfeir ◽  
Pierre Alric ◽  
...  
Keyword(s):  
Aortic Arch ◽  
Stent Graft ◽  
Endovascular Repair ◽  
Covered Stent ◽  
Type I ◽  
Type Ii ◽  
Stent Grafts ◽  
Fenestrated Stent Graft ◽  
Type I Endoleak

Purpose: To evaluate outcomes of homemade fenestrated stent-grafts for complete endovascular aortic repair of aortic arch dissections. Materials and Methods: From July 2014 through September 2018, 35 patients (mean age 66±11 years; 25 men) underwent homemade fenestrated stent-graft repair of acute (n=16) or chronic (n=10) complicated type B aortic dissections (n=16) and dissecting aortic arch aneurysms subsequent to surgical treatment of acute type A dissections (n=9). Nineteen (54%) procedures were emergent. Results: Zone 2 single-fenestrated stent-grafts were used in 25 cases; the remaining 10 were double-fenestrated stent-grafts deployed in zone 0. Median time for stent-graft modification was 18 minutes (range 16–20). Technical success was achieved in all cases. An immediate distal type I endoleak was treated intraoperatively. Among the double-fenestrated stent-graft cases, the left subclavian artery fenestration could not be cannulated in 2 patients and revascularization was required. Partial coverage of the left common carotid artery necessitated placement of a covered stent in 3 cases. One (3%) patient had a stroke without permanent sequelae. Two type II endoleaks required additional covered stent placement at 5 and 7 days postoperatively, respectively. The 30-day mortality was 6% (2 patients with ruptured aortic arch aneurysm). During a mean follow-up of 17.6±13 months, there was no aortic rupture or retrograde dissection. One late type I endoleak was treated with additional proximal fenestrated stent-graft placement. One type II endoleak is currently under observation. One additional patient died (unrelated to the aorta); overall mortality was 9%. All supra-aortic trunks were patent. Conclusion: The use of homemade fenestrated stent-grafts for endovascular repair of aortic arch dissections is feasible and effective for total endovascular aortic arch repair. Durability concerns will need to be assessed in additional studies with long-term follow-up.

Effects of Major Endoleaks on a Stented Abdominal Aortic Aneurysm

2005 ◽  
Vol 128 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Z. Li ◽  
C. Kleinstreuer
Keyword(s):  
Stent Graft ◽  
Three Dimensional ◽  
Wall Stress ◽  
Aortic Aneurysms ◽  
Type I ◽  
Abdominal Aortic ◽  
Wave Forms ◽  
Type I Endoleak ◽  
Graft Migration ◽  
The Impact

Insertion of a stent-graft into an aneurysm, especially abdominal aortic aneurysms (AAAs), is a very attractive surgical intervention; however, it is not without major postoperative complications, such as endoleaks. An endoleak is the transient accumulation of blood in the AAA cavity, which is formed by the stent-graft and AAA walls. Of the four blood pathways, a type I endoleak constitutes the major one. Thus, focusing on both proximal and distal type I endoleaks, i.e., the minute net influx of blood past the attachment points of a stent-graft into the AAA cavity, the transient three-dimensional interactions between luminal blood flow, stent-graft wall, leakage flow, and AAA wall are computationally simulated. For different type I endoleak scenarios and inlet pressure wave forms, the impact of type I endoleaks on cavity pressure, wall stress, and stent-graft migration force is analyzed. The results indicate that both proximal type I-a and distal type I-b endoleaks may cause cavity pressures close to a patient’s systemic pressure; however, with reduced pulsatility. As a result, the AAA-wall stress is elevated up to the level of a nonstented AAA and, hence, such endoleaks render the implant useless in protecting the AAA from possible rupture. Interestingly enough, the net downward force acting on the implant is significantly reduced; thus, in the presence of endoleaks, the risk of stent-graft migration may be mitigated.

scholarly journals The ability of maize Lancaster inbreds to callusogenesis in vitro under varying environmental conditions

2018 ◽  
Vol 22 ◽  
pp. 228-234 ◽  
Author(s):  
K. V. Derkach ◽  
V. V. Borysova ◽  
V. O. Maletskyi ◽  
T. M. Satarova
Keyword(s):  
Environmental Conditions ◽  
Callus Formation ◽  
Type I ◽  
Type Ii ◽  
Donor Plant ◽  
Culture In Vitro ◽  
Total Frequency ◽  
Plant Cultivation ◽  
The Impact

Aim. This work is focused on the estimation of the callusogenic potential of 10 maize Lancaster germplasm inbreds in comparison with well-known inbreds-standards with high callusogenic ability A188, Chi31 and PLS61, and the identification of genotypes with stable morphogenic callus formation under varying conditions of donor plant cultivation during three years of researches. Methods. Method of cell, tissue and organ culture in vitro. Field method. One-way and two-way analysis of variance. Results. For the investigated Lancaster inbreds the average multi-annual value of the total frequency of callusogenesis was 80.1 %, the frequency of morphogenic type I callus formation was 25.7 %, type II callus formation was 43.8 %, but for inbreds-standards these ones reached, respectively, 96.2 %, 12.2 % and 65.4 %. The level of callusogenesis varied depending on the year of investigations for all studied genotypes. The influence of genotype, year conditions and the combination of these factors on callus induction for most of the studied inbreds was significant. Conclusions. The impact of the interaction of a genotype and ecological factors of donor plant cultivation on morphogenic callusogenesis of type I as well as type II was the most significant forLancaster inbreds.Lancaster inbreds ДK298, ДK6080, ДK212 and ДK420-1 were the most stable under varying environmental conditions on the total frequency of callusogenesis, the frequencies of morphogenic and type II callus formation. None of the studied inbreds revealed the stability on type I callus formation frequency. Keywords: maize (Zea mays L.), Lancaster germplasm, callusogenesis, culture in vitro.

Type VI collagen expression is upregulated in the early events of chondrocyte differentiation

Development ◽  
1993 ◽  
Vol 117 (1) ◽  
pp. 245-251
Author(s):  
R. Quarto ◽  
B. Dozin ◽  
P. Bonaldo ◽  
R. Cancedda ◽  
A. Colombatti
Keyword(s):  
Suspension Culture ◽  
Type I Collagen ◽  
Type Ii Collagen ◽  
Type I ◽  
Type Ii ◽  
Type Vi Collagen ◽  
Full Spectrum ◽  
Collagen Expression ◽  
Hypertrophic Chondrocyte

Dedifferentiated chondrocytes cultured adherent to the substratum proliferate and synthesize large amounts of type I collagen but when transferred to suspension culture they decrease proliferation, resume the chondrogenic phenotype and the synthesis of type II collagen, and continue their maturation to hypertrophic chondrocyte (Castagnola et al., 1986, J. Cell Biol. 102, 2310–2317). In this report, we describe the developmentally regulated expression of type VI collagen in vitro in differentiating avian chondrocytes. Type VI collagen mRNA is barely detectable in dedifferentiated chondrocytes as long as the attachment to the substratum is maintained, but increases very rapidly upon passage of the cells into suspension culture reaching a peak after 48 hours and declining after 5–6 days of suspension culture. The first evidence of a rise in the mRNA steady-state levels is obtained already at 6 hours for the alpha 3(VI) chain. Immunoprecipitation of metabolically labeled cells with type VI collagen antibodies reveals that the early mRNA rise is paralleled by an increased secretion of type VI collagen in cell media. Induction of type VI collagen is not the consequence of trypsin treatment of dedifferentiated cells since exposure to the actin-disrupting drug cytochalasin or detachment of the cells by mechanical procedures has similar effects. In 13-day-old chicken embryo tibiae, where the full spectrum of the chondrogenic differentiation process is represented, expression of type VI collagen is restricted to the articular cartilage where chondrocytes developmental stage is comparable to stage I (high levels of type II collagen expression).(ABSTRACT TRUNCATED AT 250 WORDS)

Congenital Dyserythropoietic Anemia

PEDIATRICS ◽  
1973 ◽  
Vol 51 (5) ◽  
pp. 957-958
Author(s):  
G. Bennett Humphrey ◽  
Bahaod-Din Mojab ◽  
Ingomar Mutz
Keyword(s):  
Carbohydrate Metabolism ◽  
Morphological Characteristics ◽  
Type I ◽  
Type Ii ◽  
Congenital Dyserythropoietic Anemia ◽  
The 1950S ◽  
Deja Vu ◽  
Déjà Vu ◽  
Excellent Article

Reading the excellent article by Drs. Murphy and Oski, "Congenital Dyserythropoietic Anemia (CDA)",1 which further defines type II, produced a sense of deja vu. In the 1950s, nonspherocytic, hemolytic anemias (HNHA) were categorized as type I and II based on the in vitro autohemolysis test.2 This group of anemias has subsequently been demonstrated to be due to a series of enzymatic abnormalities in carbohydrate metabolism.3 In CDA, the morphological characteristics which define types I, II, and III probably reflect nuclear rather than cytoplasmic abnormalities.

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