Normal Diameter and Growth Rate of Infrarenal Aorta and Common Iliac Artery in Chinese Population Measured by Contrast-Enhanced Computed Tomography.

BACKGROUND: In previous studies, the growth rate and diameter of infrarenal aorta was paucity of Chinese data. This study aim to evaluate the normal inside diameter and growth rate of the infrarenal aorta and common iliac artery in Chinese adult population and to explore the relationship between related factors and the arterial diameter. METHODS: A retrospective study was performed among 1,340 hospitalized adult patients undergoing contrast-enhanced abdominopelvic computed tomography from April 2017 to March 2018 in our hospital. The inside diameter of infrarenal aorta and common iliac artery was measured. Linear regression was used to analyze the relationship between various factors and arterial diameter. Kruskal-Wallis H test was used to analyze the relationship between the arterial diameter and age. Mann-Whitney U test was used to analyze the relationship between arterial diameter and sex. RESULTS: The inside diameter of the infrarenal aorta was 16.49 ± 2.12 mm in male patients and 14.50 ± 1.73 mm in female patients. In male patients, the right common iliac artery was 9.77 ± 1.75 mm, and the left was 9.65 ± 1.76 mm. In female patients, the right common iliac artery was 8.59 ± 1.31 mm and the left was 8.45 ± 1.28 mm. Comparing the oldest group with the youngest, the infrarenal aortic diameter increased 27.32% in male patients and 30.11% in female patients. Right common iliac artery increased 25.13% in male patients and 30.30% in female patients. Left common iliac artery increased 25.19% in male patients and 34.26% in female patients. The growth rate increased at the beginning, reached its peak at the age of 50-60 years, and then decreased. Multiple linear regression analysis results showed that sex, age, body surface area (BSA), hypertension, and cancer were significantly correlated with the diameter of infrarenal aorta. Sex, age, BSA, and hypertension were correlated with the diameter of right common iliac artery. Sex, age, BSA, and cancer were correlated with the diameter of left common iliac artery. CONCLUSIONS: The diameter of the infrarenal abdominal aorta and common iliac artery of Chinese people is smaller than that of other countries. The abdominal aortic aneurysm (AAA) guideline might be developed based on the basic diameter to suit patients with AAA and a different basic abdominal aortic diameter. Artery diameter was increased by the age, and female patients have smaller diameter and larger arterial growth rate than male patients. Female and young patients with AAA may choose more oversize grafts for endovascular AAA repair.

Sexo e idade e sua influência sobre a anatomia da aorta abdominal e seus ramos / Age and sex and their influence on the anatomy of the abdominal aorta and its branches

Resumo Contexto Não se sabe ao certo como a idade e o sexo do paciente influenciam na anatomia da aorta abdominal e de seus ramos. Objetivos Determinar os padrões anatômicos (diâmetro e angulações) mais frequentes da aorta abdominal e de seus ramos e a influência do sexo e da idade dos pacientes sobre esses padrões. Métodos Foram avaliadas tomografias computadorizadas de abdome com contraste endovenoso de 157 pacientes. Foram aferidos calibre e angulação de artérias abdominais em indivíduos de ambos os sexos, agrupados em cinco faixas etárias: 20 a 30 anos, 31 a 40 anos, 41 a 50 anos, 51 a 60 anos e 61 a 70 anos. Foram analisadas 18 variáveis: seis ângulos de emergências arteriais, nove diâmetros arteriais, taxas de dilatação, sexo e faixa etária. Para a obtenção das medidas, utilizou-se o programa de computador RadiAnt 4.2.1 DICOM viewer (Medixant, Poznan, Polônia). Resultados Entre as 157 tomografias, 69 eram de homens e 88, de mulheres. Apresentaram diferença estatística (p < 0,05): ângulo de origem e diâmetro da artéria mesentérica superior; ângulo e diâmetro das artérias renais; diâmetro das artérias ilíacas comuns; diâmetro e taxa de dilatação em diversos segmentos da aorta, exceto na porção proximal ao tronco celíaco. Conclusões Os diâmetros da aorta (em diversos segmentos) e de seus ramos (exceto da artéria renal esquerda) aumentam progressivamente com o passar da idade em ambos os sexos e são maiores e possuem taxa de dilatação mais elevada em homens do que em mulheres da mesma faixa etária. Entre os sexos, o ângulo de emergência da artéria mesentérica superior foi maior em homens, exceto entre 20 e 30 anos; o ângulo de origem da artéria renal esquerda foi maior em mulheres entre 51 e 60 anos.

Abstract Background It is not clear how patients' age and sex influence the anatomy of the aorta and its branches. Objectives To determine the most frequent anatomical patterns of diameter and angulation of the abdominal aorta and its branches and the influence of patients' sex and age on these patterns. Methods CT scans with intravenous contrast from 157 patients were analyzed. Diameter and angulations of the abdominal aorta and its branches were measured in individuals of both sexes, classified into five age groups: 20 to 30 years, 31 to 40 years, 41 to 50 years, 51 to 60 years, and 61 to 70 years. Eighteen variables were analyzed: 6 arterial origin angles, 9 arterial diameters, rate of diameter enlargement, and patient's sex and age. RadiAnt 4.2.1 DICOM viewer software was used for measurements. Results The total of 157 CT scans were from 69 men and 88 women. There were statistical differences (p <0.05) in the following results: angle of origin and diameter of the superior mesenteric artery; renal artery angle and diameter; diameter of the common iliac arteries, and diameter and rate of diameter enlargement of the aorta in several segments, but not the segment immediately proximal to the celiac trunk. Conclusions The diameters of several aorta segments and of its branches (except the left renal artery) increase progressively with age in both sexes and are larger and have a higher rate of diameter enlargement in men than in women in the same age ranges. Between sexes, the angle of origin of the superior mesenteric artery was larger in men, except between 20 and 30 years, and the angle of origin of the left renal artery was larger in women between 51 and 60 years old.

Aortic Elastic Properties in Preschool Children Born Preterm.

OBJECTIVE: Preterm birth predisposes children to the development of cardiovascular diseases in adulthood. The aim of this study was to characterize elastic properties of the aorta at preschool age and test the hypothesis that prematurity is associated with decreased aortic distensibility and increased stiffness, both of which are predictors of increased cardiovascular risk. APPROACH AND RESULTS: In an observational study of 76 five- to seven-year-old children born at a gestational age <32 weeks and 79 term-born controls, elastic parameters of the ascending and descending abdominal aorta were determined noninvasively by means of M mode echocardiographic tracings and calculated using computerized wall contour analysis. Compared with children born at term, the preterm group showed significantly reduced distensibility and increased stiffness of the descending abdominal aorta. These results remained significant under multivariable adjustment for birth weight z score, maternal smoking in pregnancy, maternal education, family history of cardiovascular disease, breastfeeding, childhood nutrition, and current body mass index z score (multivariable odds ratios and 95% confidence intervals 5.1, 1.7-15.9; P=0.005 and 2.8, 1.0-7.9; P=0.046, respectively). Further adjustment for intravenous lipid therapy attenuated the strength of association. Elastic properties of the ascending aorta did not differ between the 2 study groups. CONCLUSIONS: Children born preterm are characterized by decreased elastic properties of the descending abdominal aorta potentially attributable to impaired viscoelastic properties of and lipid damage to the aorta. Clinical follow-up of preterm infants with a focus on aortic elastic properties may be useful for tailoring early prevention programs and counteracting cardiovascular risk in adulthood.

Segmental and age differences in the elastin network, collagen, and smooth muscle phenotype in the tunica media of the porcine aorta.

The porcine aorta is often used in studies on morphology, pathology, transplantation surgery, vascular and endovascular surgery, and biomechanics of the large arteries. Using quantitative histology and stereology, we estimated the area fraction of elastin, collagen, alpha-smooth muscle actin, vimentin, and desmin within the tunica media in 123 tissue samples collected from five segments (thoracic ascending aorta; aortic arch; thoracic descending aorta; suprarenal abdominal aorta; and infrarenal abdominal aorta) of porcine aortae from growing domestic pigs (n=25), ranging in age from 0 to 230 days. The descending thoracic aorta had the greatest elastin fraction, which decreased proximally toward the aortic arch as well as distally toward the abdominal aorta. Abdominal aortic segments had the highest fraction of actin, desmin, and vimentin positivity and all of these vascular smooth muscle markers were lower in the thoracic aortic segments. No quantitative differences were found when comparing the suprarenal abdominal segments with the infrarenal abdominal segments. The area fraction of actin within the media was comparable in all age groups and it was proportional to the postnatal growth. Thicker aortic segments had more elastin and collagen with fewer contractile cells. The collagen fraction decreased from ascending aorta and aortic arch toward the descending aorta. By revealing the variability of the quantitative composition of the porcine aorta, the results are suitable for planning experiments with the porcine aorta as a model, i.e. power test analyses and estimating the number of samples necessary to achieving a desirable level of precision. The complete primary morphometric data, in the form of continuous variables, are made publicly available for biomechanical modeling of site-dependent distensibility and compliance of the porcine aorta.

Growth rate of affected aorta in patients with type B partially closed aortic dissection.

BACKGROUND: Our purpose was to evaluate the growth rate (GR) of the affected aorta and to clarify whether a partially closed false lumen can affect aortic enlargement in patients with type B double-barrelled aortic dissection (AD). METHODS: Seventy-one patients (mean age, 64.4 years) who had experienced AD were enrolled in this study. Regular follow-up computed tomography studies (mean, 48.9 months) were performed. During the follow-up period, aortic diameter was measured with computed tomography. The fastest GR was calculated. RESULTS: Based on final computed tomography findings, the patients were divided into three groups: those with completely closed false lumens (n = 8), those with partially closed false lumens (n = 20), and those with patent false lumens (n = 43). Among the patients with partially closed false lumens, 3 of 20 (15%) had a sac formation type and 17 (85%) had a non-sac formation type. The mean fastest GRs for groups with a completely closed false lumen, partially closed false lumen, and patent false lumen were -0.2 +/- 0.6, 4.0 +/- 4.3, and 4.9 +/- 4.5 mm/year, respectively. The differences among the three groups were statistically significant (p = 0.0149). In the partially closed false lumen group, the mean fastest GRs of the sac and non-sac formation types were 12.7 +/- 1.1 and 2.6 +/- 2.7 mm/year, respectively; this difference is statistically significant (p = 0.007). CONCLUSIONS: Affected aortas with partially closed false lumens do not exhibit the highest GR. The status of a partially closed false lumen is not a significant risk factor for enlargement; however, careful follow-up study is needed whenever the sac formation type of partially closed false lumen is identified.

Lymphotoxin beta receptor signaling promotes tertiary lymphoid organogenesis in the aorta adventitia of aged ApoE-/- mice.

Atherosclerosis involves a macrophage-rich inflammation in the aortic intima. It is increasingly recognized that this intimal inflammation is paralleled over time by a distinct inflammatory reaction in adjacent adventitia. Though cross talk between the coordinated inflammatory foci in the intima and the adventitia seems implicit, the mechanism(s) underlying their communication is unclear. Here, using detailed imaging analysis, microarray analyses, laser-capture microdissection, adoptive lymphocyte transfers, and functional blocking studies, we undertook to identify this mechanism. We show that in aged apoE(-/-) mice, medial smooth muscle cells (SMCs) beneath intimal plaques in abdominal aortae become activated through lymphotoxin beta receptor (LTbetaR) to express the lymphorganogenic chemokines CXCL13 and CCL21. These signals in turn trigger the development of elaborate bona fide adventitial aortic tertiary lymphoid organs (ATLOs) containing functional conduit meshworks, germinal centers within B cell follicles, clusters of plasma cells, high endothelial venules (HEVs) in T cell areas, and a high proportion of T regulatory cells. Treatment of apoE(-/-) mice with LTbetaR-Ig to interrupt LTbetaR signaling in SMCs strongly reduced HEV abundance, CXCL13, and CCL21 expression, and disrupted the structure and maintenance of ATLOs. Thus, the LTbetaR pathway has a major role in shaping the immunological characteristics and overall integrity of the arterial wall.

Angiographic, ultrasonographic, and macroscopic assessment of aortic growth after VCS clips, interrupted polypropylene, or running polyglycolic acid anastomosis.

BACKGROUND/PURPOSE: Lack of growth after surgery is still an unsolved issue in growing vessels. Aortic surgery is an integral part of vascular pediatric surgery. As an alternative to address this lack of growth in this scenario, we propose the use of titanium clips for vascular anastomosis. METHODS: Thirty-two domestic swine were used in this study. Animals entered the study when they were 55 days old and were subjected to an end-to-end aortic anastomosis using vascular closure stapler (VCS) clips, interrupted polypropylene, or running polyglycolic acid suture. Control group animals were sham-operated. Pigs were allowed to grow for 6 months, during which time they were subjected to serial ultrasonographic and angiographic studies to assess vascular growth. RESULTS: VCS clip anastomosis outcome was comparable with polypropylene or polyglycolic acid suture anastomosis. No significant differences in either longitudinal or transversal vascular growth were seen between the 3 studied suturing techniques and the control group. CONCLUSIONS: Our vascular growth and patency results suggest that VCS clips may provide a suitable alternative to conventional suture in pediatric aortic vascular surgery.

Digital-image analysis of the angiographic patterns of the popliteal artery in patients with aorto-iliac occlusive disease (Leriche syndrome).

Angiographic patterns of the popliteal artery are of great clinical relevance in vascular surgery below the knee. Using radiological, digital and statistical methods the variants and Luminal diameters of the popliteal artery branching in 46 men and 30 women with Lerich syndrome were studied. Statistical analysis did not reveal any gender or syntopic dimorphisms (P > or = 0.05). In subtype IA (87.5%) the anterior tibial artery and the short type of posterior tibioperoneal trunk were found. In subtype IB (2.63%) an arterial trifurcation was observed. In subtype IC (1.97%) the posterior tibial artery and the short type of anterior tibioperoneal trunk were seen. In two subtypes: IIA-1 (1.32%) and IIA-2 (0.66%) the anterior tibial artery and the long type of posterior tibioperoneal trunk were found. In subtype II B (5.92%) the long type of anterior tibioperoneal trunk and the posterior tibial artery were observed. The symmetry of the left and right poptiteal patterns was seen in two most frequent subtypes: I A (r1 = 0.80) and II B (r2 = 0.83). Either the anterior or posterior tibial artery had a smaller diameter than the coexisting tibioperoneal trunk (P<0.01). In a trifurcation the luminal diameters formed a decreasing sequence of the following arteries: anterior tibial, posterior tibial and peroneal. The angiometric analysis of luminal diameters showed the predominant vessel in each subtype: anterior tibioperoneal trunk (IC, IIB), posterior tibioperoneal trunk (IA, IIA-1, IIA-2) and anterior tibial artery (IB).

Dual role of VEGF in pretreated experimental ePTFE arterial grafts.

BACKGROUND: Lack of endothelialization and abnormal smooth muscle cell (SMC) growth adversely affect the outcome of vascular synthetic grafts. The aims of our study were to investigate how a coating of extracellular matrix (ECM) and vascular endothelial growth factor (VEGF) might affect the endothelialization rate, smooth muscle cells (SMC) proliferation, and myointimal hyperplasia in experimental arterial ePTFE grafts. METHODS: In each of 30 male Lewis rats, a 1-cm-long ePTFE graft was inserted at the level of the abdominal aorta. Animals were randomized in five groups (six animals each): groups A and A1 received ePTFE grafts coated with a synthetic extracellular matrix (growth factor-reduced matrigel) containing VEGF; groups B and B1 received ePTFE grafts coated with synthetic ECM; and group C received ePTFE grafts alone. The grafts were explanted at 30 days from surgery for immunohistochemical analysis. RESULTS: Both endothelialization rate and myointimal hyperplasia were augmented in group A versus groups B and C, and these findings were statistically significant. SMC density resulted significantly higher in group A versus groups B and C, and this was associated with an altered expression of bFGF and TGFbeta. CONCLUSIONS: Pretreating ePTFE grafts with synthetic ECM and VEGF results in better endothelialization, but also in undesired higher SMC density and myointimal hyperplasia.

Cryosurgical effects on growing vessels.

Cryosurgical treatment of unresectable hepatic malignancies has proven beneficial in adults. Concerns regarding its use in children include the effect on growth and the risk of injury to adjacent structures. To test the effect of cryoablation on adjacent vascular structures in a growing animal, liquid nitrogen cryoablation was performed on a juvenile murine model. Sprague Dawley rats underwent double freeze-thaw cryoablation of the abdominal aorta with interposed liver tissue. Serial sacrifices were performed over 120 days. Comparisons were made with sham-operated controls. Overall, animal growth paralleled that of sham controls through all time points. Gross examination of aortic diameter also showed similar growth in vessel size between the groups. Histologic analysis demonstrated injury after cryoablation with smooth muscle cell vacuolization, followed by cell death. Aortic media layer collapse resulted from cellular loss, however, elastin fiber composition was maintained. Aortic patency was preserved despite evidence of cellular injury and aortic wall remodeling. An associated thermal sink effect on the opposing wall was identified. After cryoablation adjacent to the abdominal aorta in adolescent rats, vascular patency is maintained and animal growth and structural function is preserved, despite cellular injury and wall compression. These observations suggest that cryoablation may be a useful treatment adjunct in young subjects.

Growth potential of aortic autografts and allografts: effects of cryopreservation and immunosuppression in an experimental model.

OBJECTIVE: An animal model has been used to evaluate the potential of growth of vascular autografts and allografts, and the effects of cryopreservation, rejection and immunosuppression on this growth. METHODS: In 35 animals (seven groups of five female NZW rabbits; age 5-6 weeks; weight 1.1 kg), a graft interposition was performed at the level of the infrarenal aorta. Different groups included fresh autografts, fresh and cryopreserved consanguineous allografts (donor: litter sister), fresh and cryopreserved immunosuppressed (IS) consanguineous allografts (receiving cyclosporin 10 mg/kg per day) and fresh and cryopreserved allografts. Animals were allowed to grow normally and were sacrificed at the mean weight of 2.89 kg. We studied the growth of the native aorta and of the graft and calculated the growth ratio (growth of the graft/growth of native vessel). Grafts and adjacent aorta were histologically studied. RESULTS: Growth of the graft was normal (mean ratio 1.08; S.D. = 0.21) for autografts, and for fresh and cryopreserved IS consanguineous grafts. Growth was absent (mean ratio 0.12; S.D. = 0.15) for fresh and cryopreserved allografts (P = 0.0001). In consanguineous grafts without IS, growth was absent or normal, presumably according to genetic compatibility, but never intermediate. Histological study showed normal optic microscopic aspects when growth was normal and, when growth was absent, aspects compatible with rejection including mainly intimal hyperplasia and medial thinning. CONCLUSIONS: (1) Normal growth of arterial autografts was confirmed; (2) cryopreservation did not prevent potential growth of an arterial graft; and (3) in an allogenic situation, without IS, an aortic graft, fresh or cryopreserved, never showed any growth potential.

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.

Age-related changes of aorta in Syrian hamsters of APA strain.

Age related changes in thoracic aorta (TA) and abdominal aorta (AA) of male APA hamsters from 3 to 12 months of age were examined morphometrically and ultrastructurally. The nuclear density of smooth muscle cells (SMCs) was larger in AA than in TA, and it decreased with advancing age. In contrast, the collagen fibre density was larger in TA than in AA, and it increased correlatively with aging, especially in TA. Electron microscopic examinations revealed that subendothelial cystic spaces and aggregations of fragments of elastic and collagen fibres were found at 3 months of age and progressed with advancing age in TA, while they were not evident in AA even at 12 months of age. Irregularity of medial SMC contours and an amount of SMC-associated collagen fibres were more prominent in TA than in AA throughout the experimental period. Degenerative changes of endothelial cells and medial SMCs progressed with aging in both TA and AA, and degenerated SMCs were characterized by aggregations of swollen mitochondria.

Increased production of tumor necrosis factor and interleukin-6 by arterial wall of aged rats.

Plasma cytokine levels are enhanced in aged animals and in elderly people. Vascular cells are known to be both targets and sources of cytokines. To investigate the effect of aging on vascular cytokine synthesis, we studied tumor necrosis factor (TNF), interleukin-6 (IL-6), and prostacyclin (PGI2) production by the arterial wall using organoid culture of aorta from 10- (n = 8) and 30-mo-old (n = 8) rats, after activation by lipopolysaccharide (LPS). Biological activity of TNF and IL-6 was measured in supernatant from incubated vessels. 6-Ketoprostaglandin F1 alpha (6-keto-PGF1 alpha), a stable metabolite of PGI2, a secondary inflammatory mediator, was measured using enzyme immunoassay. In the absence of LPS, TNF production was undetectable in most animals and was not significantly increased in the aged group. By contrast IL-6 and 6-keto-PGF1 alpha productions, in the absence of LPS, were significantly greater in 30- (8,140 +/- 1,350 U/micrograms DNA and 23.2 +/- 6.4 ng/micrograms DNA, respectively) than in 10-mo animals (3,060 +/- 350 U/micrograms DNA and 8.4 +/- 1.6 ng/micrograms DNA, P < 0.01 and P < 0.05, respectively). LPS-induced production of TNF, IL-6, and 6-keto-PGF1 alpha was significantly increased in old rats, being increased respectively by 3.2-, 3.5-, and 2.4-fold at 1 ng/ml LPS, compared with the production in young rats. Because TNF and IL-6 are capable of regulating vascular cell function such as proliferation protein synthesis and contractility, these cytokines might play a major role in age-related remodeling of arteries and age-related vascular diseases.

Vascular Ca overload produced by vitamin D3 plus nicotine diminishes arterial distensibility in rats.

In humans, aging produces many structural changes in blood vessels, one of the most pronounced being arterial calcium overload. Simultaneously arteries become increasingly rigid. The slow evolution of the two processes renders it difficult to evaluate the importance of vascular calcium overload in the development of decreased compliance. To gain insight into this relationship, rapid vascular calcium overload was produced by treating young rats with vitamin D3 and nicotine. When rats were allowed 16 days or longer to recover from such treatment, analysis of plasma parameters revealed no overt toxicity, and growth rate was similar to that of controls. Pronounced calcium overload was seen primarily in compliance arteries. Changes in systemic arterial compliance, characteristic impedance, pulse-wave velocity, and carotid compliance all reflected a substantial increase in arterial rigidity. Linear regression analysis revealed significant correlations between the various indicators of arterial distensibility and arterial calcium content. In conclusion, treatment of young rats with vitamin D3 and nicotine may provide a suitable model with which to investigate how calcium overload is involved in the induration of compliance arteries.

[Growth of the aortic anastomosis in puppies--comparison of monofilament suture materials, whether absorbable or nonabsorbable, and of suture techniques, whether continuous or interrupted].

This study compared the growth of vascular anastomoses performed with either polypropylene or polydioxanone sutures and with either continuous running suture or interrupted suture technique. Primary end-to-end anastomoses of the infrarenal aorta were performed in 38 puppies. Nineteen were performed with 5-0 polypropylene sutures; in ten all sutures were placed in continuous fashion, and in nine in interrupted fashion. The other nineteen were performed with 5-0 polydioxanone sutures; in ten the sutures were placed in continuous fashion, and in nine in interrupted fashion. The animals were subjected to the repeated aortograms at 2, 4, 8 weeks, 6 months and 1 year following operation. Each abdominal aorta was subjected to burst test, and pathological examination. All anastomoses were patent and tolerated burst-test (300 mmHg). Neither aneurysm nor dilatation of anastomotic site was observed. Anastomotic area was significantly smaller and more stenotic in the continuous polypropylene suture group than in other three groups at 8 weeks, 6 months and 1 year following operation. There was no significant difference among these three groups. No suture materials were observed in the polydioxanone suture groups after 6 months following operation. This study suggests that polydioxanone suture will be useful for the repair of cardiovascular anomalies where growth of the suture line is required.

Results of aortic anastomoses made under tension using polydioxanone suture.

After early repair of congenital cardiovascular defects, such as coarctation of the aorta, late stenosis may become a problem. Use of absorbable sutures has been shown to be superior to use of nonabsorbable sutures in allowing growth of an anastomotic site along with the individual. Some concern has been raised, however, about the potential for aneurysm formation at the site of anastomosis when absorbable sutures are used. This study was undertaken to observe the effects of longitudinal tension on anastomoses made with absorbable polydioxanone suture in growing animals. Six piglets (aged 3 to 4 weeks) underwent a 1-cm resection of the infrarenal aorta and reanastomosis with polydioxanone suture. One animal died prematurely of respiratory illness. The 5 remaining animals were killed after 6 months. The excised aortas demonstrated no stenosis, no dilatation, and no burst-test failure to 250 mm Hg. Histological examination showed disrupted elastic laminae without thinning of aortic wall in all samples of aorta. We conclude that polydioxanone suture is a suitable suture material for vascular anastomoses made under tension where growth of the anastomotic site is expected.