Proximal Aortic Segments Research Articles

Managing the Root in Acute Type A Aortic Dissections: Are We Ready for a Standardized Approach?

Surgical repair of Type A aortic dissection (TAAD) requires exclusion of the primary entry tear and reestablishment of flow into the distal true lumen. Provided that the majority of tears occur within the ascending aorta (AA), replacing only that segment seems a safe option; however, this strategy leaves the root susceptible to dilatation and need for reintervention. We aimed to review the outcomes of the two strategies: aortic root replacement (ARR) and isolated ascending aortic replacement. Retrospective analysis of prospectively collected data for all consecutive patients who underwent repair of acute TAAD at our institution from 2015 to 2020 was conducted. Patients were divided into two groups: (1) ARR and (2) isolated AA replacement as index operation for TAAD repair. Primary outcomes were mortality and need for reintervention during the follow-up. A total of 194 patients were included in the study; 68 (35%) in the ARR group and 126 (65%) in the AA group. There were no significant differences in postoperative complications or in-hospital mortality (23%; p = 0.51) between groups. Seven patients (4.7%) died during follow-up and eight patients underwent aortic reinterventions, including proximal aortic segments (two patients) and distal procedures (six patients). Both aortic root and AA replacement are acceptable and safe techniques. The growth of an untouched root is slow, and reintervention in this aortic segment is infrequent compared with distal aortic segments, hence preserving the root could be an option for older patients provided that there is no primary tear within the root.

Morphological Structure of the Aortic Wall in Deep Diving Cetacean Species: Evidence for Diving Adaptation.

Simple SummaryDiving implies cardiovascular adaptations in marine mammals. The work aimed to analyze the aortic wall in nine cetacean species with deep diving habits belonging to four families. We hypothesize that variations in the aortic wall will reflect the diving capability of each species. The analyses showed that the elastic component was higher in the initial part of the artery, the muscular elements increased in the distal portion in all cases, and the apparent organization of the components in the aortic wall did not show essential modifications between the four families. All species presented a decrease in the arterial wall thickness along the aorta. The reduction was dramatic between the initial and thoracic aorta in the sperm whale specimens; meanwhile, the species of the other three families, beaked whale, pygmy sperm whale, and deep-diving dolphins, showed a more uniform decrease between the aortic segments. Because of the diving habits described for the different species, our findings support that a decrease in the arterial wall thickness between the aortic segments is the most relevant characteristic related to diving adaptation.This study analyses the aortic wall structure in nine cetacean species with deep diving habits belonging to four Odontoceti families: Ziphiidae, Kogiidae, Physteridae, and Delphinidae. Samples of ascending, thoracic and abdominal aorta were processed for histological and morphometric studies. The elastic component was higher in the proximal aortic segments, and the muscular elements increased distally in all cases. Morphometric analyses showed that all families presented a decrease in the thickness of the arterial wall and the tunica media along the aorta. The reduction was dramatic between ascending and thoracic aorta in the Physeteridae specimens; meanwhile, the other three families showed a more uniform decrease between the ascending, thoracic and abdominal aorta. The decline was not correlated with a reduced elastic or lamellar unit thickness but with a loss of lamellar units. The organization of the elements in the aortic wall did not show essential modifications between the four families, resembling the structure described previously in the shallow and intermediate diving dolphins. Our findings support that the difference in the morphometric characteristics of the different segments in the aortic wall is likely related to the diving habit more than the absolutes values of any other parameter.

Location of Aortic Enlargement and Risk of Type A Dissection at Smaller Diameters

BackgroundPrevious work has demonstrated that more than one-half of acute type A aortic dissections (ATADs) occur at a maximal aortic diameter (MAD) of <5.5 cm. However, no analysis has investigated whether ATAD risk at smaller MADs is more common with modest dilation of the aortic root (AR) or supracoronary ascending aorta (AA) in patients without genetically triggered aortopathy. ObjectivesThis study sought to determine if the segment of modest aortic dilation affects risk of ATAD. MethodsUsing the International Registry of Acute Aortic Dissection (IRAD) database from May 1996 to October 2016, we identified 667 ATAD patients with MAD <5.5 cm. Patients were stratified by location of the largest proximal aortic segment (AR or AA). Patients with known genetically triggered aortopathy were excluded. MADs at time of dissection were compared between AR and AA groups. Secondary outcomes included operation, postoperative outcomes, and long-term survival. ResultsOf patients with ATAD at an MAD <5.5 cm, 79.5% (n = 530) were in the AA group and 20.5% (n = 137) in the AR group. Modestly dilated ARs (median MAD 4.6 cm [IQR: 4.1-5.0 cm]) dissected at a significantly smaller diameter than modestly dilated AAs (median MAD 4.8 cm [IQR: 4.4-5.1 cm]) (P < 0.01). AR patients were significantly younger than AA patients (58.5 ± 13.0 years vs 63.2 ± 13.3 years; P < 0.01) and more commonly male (78% vs 65%; P < 0.01). Postoperative and long-term outcomes did not differ between groups. ConclusionsATAD appears to occur at smaller diameters in patients with modest dilation in the AR vs the AA (4.6 vs 4.8 cm). These findings may have implications for future consensus guidelines regarding the management of patients with aortic disease.

Enlarged Lumen Volume of Proximal Aortic Segment and Acute Type B Aortic Dissection: A Computer Fluid Dynamics Study of Ideal Aortic Models.

BackgroundRecent study has revealed that enlarged diameters of the ascending aorta and proximal aortic arch enhance the probability of ATBAD. However, little is understood about the relation to ATBAD.ObjectiveThis study explored the differences in proximal aortic segment (PAS) morphology in patients with acute type B aortic dissection (ATBAD), and performed hemodynamic simulations to provide proof of principle.Materials and MethodsThe morphological characteristics of PAS in the ATBAD group (n = 163) and corresponding segment in the control group (n = 120) were retrospectively measured. The morphological parameters were analyzed using comprehensive statistical approaches. Ridge regression analysis was also performed to determine the association between independent variable and dependent variable. P < 0.01 was considered significant. Idealized aortic models were established based on variables of statistical significance, and hemodynamic simulations were performed to evaluate blood flow changes caused by morphology.ResultsDiameters at landmarks of PAS were significantly larger in the ATBAD group. The lumen volume (VPAS) of PAS in the ATBAD group was significantly enlarged than that of the control group (124,659.07 ± 34,089.27 mm3 vs 89,796.65 ± 30,334.40 mm3; P < 0.001). Furthermore, the VPAS was positively correlated to diameters. As the VPAS increased, the fluid kinetic energy in PAS enhanced linearly, and time-averaged wall shear stress and oscillatory shear index at the distal area of the left subclavian artery increased significantly.ConclusionIn the ATBAD group, the enlarged VPAS and increased diameters of PAS are positively correlated. Meanwhile, the enlarged VPAS leads to more aggressive hemodynamic parameters at the distal area of the left subclavian artery, which may create a contributory condition for ATBAD.

Risk stratification of ulcer-like projection in uncomplicated acute type B aortic intramural haematoma

Abstract OBJECTIVES This study aimed to investigate the morphological evolution and risk stratification of ulcer-like projection (ULP) in patients with uncomplicated acute type B aortic intramural haematoma. METHODS A retrospective study was conducted on patients with uncomplicated acute type B intramural haematoma admitted in our institution from January 2015 to June 2020. The primary end points were adverse aortic events (AAE), including aortic rupture, aortic dissection, aortic aneurysm and ULP enlargement. RESULTS The study cohort comprised 140 patients, including 62 (44%) and 78 (56%) patients with and without initial ULP, respectively. AAE occurred in 13 patients (9%) in the early term and 42 patients (33%) in the mid-term. Compared with patients without ULP, patients with initial ULP had no significant difference in early outcomes but a higher mid-term AAE rate [8% vs 11%, odds ratio (OR) 1.5, P = 0.47; 17% vs 55%, OR 6.0, P &amp;lt; 0.001]. Significantly higher AAE rate was observed in patients with high-risk ULP (depth ≥5.0 mm and located in the proximal aortic segments) than those with only low-risk ULP (depth &amp;lt;5.0 mm and/or located in the distal aortic segments) (87% vs 51%, OR 6.2, P = 0.014). In the multivariable analysis, high-risk ULP was an independent predictor of AAE (hazard ratio 2.8, P = 0.009). CONCLUSIONS High-risk ULP is a rapidly evolving entity and a marker of AAE despite optimal medical therapy. Therefore, close follow-up and prompt intervention are recommended for patients with high-risk ULP.

L-Arginine reduces downstream vascular contractility after flow-diverting device deployment: A preliminary study in a rabbit model.

Flow diverters (FDs) are an effective treatment for intracranial aneurysms, though not free from hemorrhagic complications. A previous study demonstrated increased vascular contractility after FD-implantation as a potential mechanism of distal complications. Our study aimed to investigate whether L-arginine medication affects vascular contractility following FD deployment in a rabbit model. FDs were implanted in the aorta of normal rabbits (+FD, n = 10), with sham-operated aorta as controls (n = 5). L-Arginine was given in the drinking water (2.25% L-arginine hydrochloride) of half of the +FD animals (+FD/+Arg). Force contraction vascular contractility studies were performed on the aortic rings proximal and distal to the FD using an organ bath. Total eNOS, eNOS(pS1177), eNOS(pT495), COX-2, and S100A4 were quantified by western analysis on total protein lysates from aortic segments, normalizing to GAPDH. Mean vascular contractility was 53% higher in distal relative to proximal aortic segments (P = 0.0038) in +FD animals, but were not significantly different in +FD/+Arg animals, or in sham-operated controls. The +FD animals expressed significantly reduced levels of eNOS(pS1177) than sham-operated controls (P = 0.0335), while both the +FD and +FD/+Arg groups had reduced levels of eNOS(pT495) relative to sham-operated controls (P = 0.0331 and P = 0.0311, respectively). These results suggest that L-arginine medication reduces distal vascular contractility after FD treatment via nitric oxide production and thus might mitigate risk for downstream complications.

P1448 Thoracic aorta and circulating transforming growth factor-b in marfan syndrome and marfanoid habitus

Abstract Purpose Current understanding of the pathogenesis of thoracic aortic aneurysm (TAA) in Marfan syndrome (MS) focuses upon abnormal activity of the transforming growth factor beta (TGF-β) signalling pathway. Circulating TGF-β predicts cardiovascular events in patients with MS and is elevated in the entire spectrum of aortic syndromes. Marfanoid habitus (MH) patients not meeting the MS criteria (TAA, ectopia lentis, family history), but share the same skeletal features and are the part of the Marfan continuum. Our aim was to evaluate the possible role of elevated TGF-β level in the aortic dilatation at mid-term follow-up in Marfanoid habitus patients. Methods 33 consecutive patients with a presumptive clinical diagnosis of Marfan syndrome were referred to Almazov centre and enrolled in our observational, prospective, single-center study. Nine of them (mean age 27.9 ± 9.3) fulfilled diagnosis of MS according to revised Ghent criteria. 24 subjects (mean age 21.8 ± 3.4) with skeletal features of Marfanoid habitus have had no major findings of MS. Proximal aortic segments were visualized in the parasternal long-axis and suprasternal views. Concentration of TGF-β1 and TGF-β2 in serum was determined using a test system Human Platinum ELISA. End points analyzed during 5 years of follow-up were mortality, aortic-related events, and aortic dimension changes. Results During 122 person-years of the follow-up (median 5.1 years) no deaths or aortic-related events occurred in Marfanoid habitus patients. TGF-β1 and TGF-β2 serum levels were elevated in patients with Marfanoid habitus (14.2 ± 27.6 and 2.1 ± 1.7 ng/ml, respectively) but were lower than in MS group (44.6 ± 47.3 ng/ml, p = 0.03 and 2.7 ± 1.7 ng/ml, p = 0.39, respectively). A high TGF-β1 serum level (cutoff &amp;gt;14.75 ng/ml, provided by the manufacturer of our TGF-β assay) was detected in 44% and TGF-β2 (&amp;gt;2.0 ng/ml) in majority patients (67%) of the MS group. In Marfanoid habitus group we found a high TGF-β1 serum level only in 4 (17%) patients and TGF-β2 in 9 (38%) patients. Aortic diameter at the sinuses of Valsalva and Z-score were significantly lower in Marfanoid habitus group (29.2 ± 2.8 mm and 1.56 ± 0.93) than in MS patients (43.1 ± 15.1 mm, p = 0.0007 and 6.86 ± 5.83, p = 0.004) at the beginning of study and significantly increased during the follow-up (31.3 ± 2.9 mm and 1,69 ± 0,15, p &amp;lt; 0.001 for both). There was no correlation between TGF-β level and aortic dimensions in patients with MS and marfanoid habitus. Conclusion In young adults with Marfanoid habitus and the current absence of ascending aortic aneurysm we found the increased TGF-β level and aortic root enlargement during the follow-up. High TGF-β serum level may contribute to the excessive progression of aortic dilatation later over mid-to-late aging and requires further investigation to establish its role in the aortic aneurysm pathogenesis.

Thoracic Aortic Aneurysms - Diagnosis and Treatment Strategies

Thoracic aortic aneurysms are a relatively uncommon disease, with an incidence of 10.4/100 000, with an increase in the last decades, due to the increased quality of vascular screening. Several imaging techniques like thoracic radiography, echocardiography, magnetic resonance (MRI) or positron emission tomography (PET) can be used for the diagnosis of such condition, whose first diagnosis is usually incidental. The gold standard for aneurysm evaluation is computed tomography angiography (CTA), which allows precise diameter assessment and accurate preoperative planning. Advancements in imaging techniques, through electrocardiography (ECG)-gated CTA, permit to avoid movement artifacts and have a more precise definition of proximal aortic segments (aortic arch, ascending aorta).The urgent or emergent treatment of thoracic aneurysms is indicated in symptomatic patients and in case of rupture, respectively. The current European Society for Vascular Surgery guidelines recommend the elective treatment of thoracic aneurysms with a diameter > 55 mm, since diameters of 55 - 60 mm are associated with a rupture risk of 10 %/year. Lower perioperative morbidity and mortality rates have been demonstrated for endovascular repair in comparison with open surgery. According to the current guidelines, the treatment of choice is endovascular, through the implantation of an aortic stent graft (thoracic endovascular aortic repair, TEVAR), while open surgery is reserved to young patients, fit for open surgery. Hybrid procedures, introduced in 2000, include the debranching of supra aortic vessels and TEVAR and are a well established procedure for the treatment of aneurysms involving the aortic arch. The increasing research and expertise in endovascular surgery lead to the development of complex procedures, like chimney TEVAR, fenestrated and branched TEVAR which allowed to reach proximal landing zone to the ascending aorta.

Air Embolism During TEVAR

Purpose: To investigate the amount of gas released from Zenith thoracic stent-grafts using standard saline flushing vs the carbon dioxide flushing technique. Methods: In an experimental bench setting, 20 thoracic stent-grafts were separated into 2 groups of 10 endografts. One group of grafts was flushed with 60 mL saline and the other group was flushed with carbon dioxide for 5 minutes followed by 60 mL saline. All grafts were deployed into a water-filled container with a curved plastic pipe; the deployment was recorded and released gas was measured using a calibrated setup. Results: Gas was released from all grafts in both study groups during endograft deployment. The average amount of released gas per graft was significantly lower in the study group with carbon dioxide flushing (0.79 vs 0.51 mL, p=0.005). Conclusion: Thoracic endografts release significant amounts of air during deployment if flushed according to the instructions for use. Application of carbon dioxide for the flushing of thoracic stent-grafts prior to standard saline flush significantly reduces the amount of gas released during deployment. The additional use of carbon dioxide should be considered as a standard flush technique for aortic stent-grafts, especially in those implanted in proximal aortic segments, to reduce the risk of air embolism and stroke.

Usefulness of Losartan on the Size of the Ascending Aorta in an Unselected Cohort of Children, Adolescents, and Young Adults With Marfan Syndrome

Since 2008, when angiotensin II type I receptor blockade with losartan was introduced in the prevention of cardiovascular manifestation of Marfan syndrome (MFS), a specific treatment to address the cardiovascular lesions became available. The present study aimed to compare the response of such in an unselected cohort of patients with genotyped MFS. At a tertiary university children's hospital, 20 pediatric and adolescent patients aged 1.7 to 21.6 years with genetically proven MFS were enrolled in a prospective treatment study of losartan for evaluation of the aortic dimensions and elasticity indexes. The mean follow-up period was 33 ± 11 months. A significant reduction in the normalized aortic dimensions with losartan was observed in the valve, root, sinotubular junction, and ascending aortic segments (p = 0.008, p <0.001, p = 0.012, and p = 0.001, respectively). No correlation between elasticity behavior and the decrease in the aortic dimension with losartan therapy was detectable. A significant correlation between stronger improvement and younger age at onset (r = 0.643, p = 0.002) and a longer therapy duration (r = -0.532, p = 0.016) was verifiable. However, no correlation between improvement with therapy and the type of mutation or presentation of clinical forms was remarkable. Elasticity also seemed to improve but not significantly. In conclusion, in our cohort of young patients with MFS, a significant improvement with losartan monotherapy was proved in all affected proximal aortic segments, with a better response to therapy when started at an earlier age and with a longer therapy duration.

Insights into the Pathogenesis of Exercise Limitation and Right Ventricular (RV) Afterload in Pulmonary Arterial Hypertension (PAH)

while there was no difference in the PDA (1.0± 1.2 vs 1.1± 0.49, P= 0.26) and DDA (1.1± 1.1 vs 1.3± 0.9, P= 0.97). Conclusion: This study shows for the first time that aortic stiffening may preferentially occur in the proximal aortic segments in patients with AS. http://dx.doi.org/10.1016/j.hlc.2012.05.049 40 ysis with urokinase, LIBS-MB ultrasound-imaging allows monitoring of the reduction of thrombus area (p< 0.001). Similar trends of results were obtained when comparing the thrombus area reduction to thrombus area greyscale intensity unit reduction. Conclusions: We demonstrate that GPIIb/IIIa-targeted microbubbles specifically bind to activated platelets in vitro and in vivo. We demonstrated high resolution real-time molecular ultrasound imaging of acute arterial thrombosis and in addition we could directly monitor success or failure of pharmacological thrombolysis. This non-invasive and cost-effective imaging modality provides a unique opportunity to detect (micro)thrombi at an early stage allowing for early diagnosis and thus timely therapy. http://dx.doi.org/10.1016/j.hlc.2012.05.050

Transforming growth factor-β signaling in hypertensive remodeling of porcine aorta

A porcine aortic coarctation model was used to examine regulation of gene expression in early hypertensive vascular remodeling. Aortic segments were collected proximal (high pressure) and distal (low pressure) to the coarctation after 2 wk of sustained hypertension (mean arterial pressure>150 mmHg). Porcine 10K oligoarrays used for gene expression profiling of the two regions of aorta revealed downregulation of cytoskeletal and upregulation of extracellular region genes relative to the whole genome. A genomic database search for transforming growth factor-beta (TGF-beta) control elements showed that 19% of the genes that changed expression due to hypertension contained putative TGF-beta control elements. Real-time RT-PCR and microarray analysis showed no change in expression of TGF-beta1, TGF-beta2, TGF-beta3, or bone morphogenetic proteins-2 and -4, yet immunohistochemical staining for phosphorylated SMAD2, an indicator of TGF-beta signaling, and for phosphorylated SMAD1/5/8, an indicator of signaling through the bone morphogenetic proteins, showed the highest percentage of positively stained cells in the proximal aortic segments of occluded animals. For TGF-beta signaling, this increase was significantly different than for sham-operated controls. Western blot analysis showed no difference in total TGF-beta1 protein levels with respect to treatment or aortic segment. Immunohistochemistry showed that the protein levels of latency-associated peptide was decreased in proximal segments of occluded animals. Collectively, these results suggest that activation of TGF-beta, but not altered expression, may be a major mechanism regulating early hypertensive vascular remodeling.

Cardiovascular magnetic resonance-derived aortic distensibility: validation and observed regional differences in the elderly

Applanation tonometry evaluation of pulse wave velocity is widely accepted as the 'gold standard' method for noninvasively assessing arterial stiffness. Newer noninvasive tools such as cardiovascular magnetic resonance can also evaluate arterial stiffness, but have not been validated. The aim of this study was to validate cardiovascular magnetic resonance-derived aortic distensibility with pulse wave velocity and to investigate age-related changes in regional aortic distensibility. Ten young (20-30 years) and ten old (60-70 years) patients underwent applanation tonometry assessment of pulse wave velocity. Cardiovascular magnetic resonance measurements of arterial stiffness were evaluated by aortic distensibility (10-3 mmHg-1) at three separate locations, the ascending aorta, proximal descending aorta and distal descending aorta. Pulse wave velocity correlated strongly with aortic distensibility measurements at each site: ascending aorta R2 = 0.57, proximal descending aorta R2 = 0.60 and distal descending aorta R2 = 0.72. As expected, the old cohort had significantly increased aortic stiffness compared with the young cohort (P < 0.01). Post-hoc comparison showed an increase in proximal stiffness in the old cohort compared with the young cohort (P = 0.018). Cardiovascular magnetic resonance-derived aortic distensibility is an accurate measure of arterial stiffness and can evaluate regional stiffness through the aorta. Furthermore, our results suggest that aortic stiffening may preferentially occur in the proximal aortic segments in the elderly.

Sobrevida tardia de pacientes submetidos à correção aberta eletiva de aneurisma de aorta abdominal

CONTEXTO: Os autores fazem uma revisão dos pacientes operados em hospital privado para determinar a causa da mortalidade tardia, a evolução dos demais segmentos da aorta e as complicações relacionadas à prótese. OBJETIVOS: Relatar o seguimento tardio de uma série de 76 casos operados eletivamente para a correção de aneurisma de aorta abdominal, no período de março de 1995 a janeiro de 2007. MÉTODOS: Convocação dos pacientes para uma consulta de retorno e daqueles que não puderam comparecer pessoalmente através de contato telefônico. RESULTADOS: A mortalidade operatória em 30 dias foi de 5,3%. A sobrevida tardia obtida por curva atuarial foi de 95% em 1 ano, 88% em 3 anos e 72% em 8 anos. As doenças cardiovasculares foram a principal causa de mortalidade tardia, seguidas das neoplasias malignas. A dilatação de segmento de aorta proximal à correção cirúrgica ocorreu em 9,7% dos pacientes operados, e as complicações relacionadas à prótese ocorreram em quatro casos (5,3%), sendo uma infecção de prótese, um pseudo-aneurisma proximal, um pseudo-aneurisma em ilíaca e uma oclusão de ramo. CONCLUSÃO: A cirurgia aberta para correção do aneurisma de aorta abdominal apresenta bom resultado em longo prazo, semelhante ao da literatura nacional e internacional, sendo uma boa opção para o paciente que tenha um baixo risco cirúrgico.

Aortic correlates of clinical markers of large artery structure and function. Effects of aging and hypertension

Non-invasive measures of large artery structure and function--such as aorto-femoral pulse wave velocity (PWV), arterial compliance (AC) and common carotid intima-media thickness (CCA IMT)--can predict new CV events, independently of traditional CV risk factors. However, neither their relations with aorta properties nor the effects of aging and hypertension on those relations are yet clear. 40 subjects (18 M, 22 F; mean age 60+/-16 yrs, range 21-83 yrs) free of any acute CV event, valve disease or atrial fibrillation, were studied. Aortic IMT, diastolic diameter (D) and distensibility (Dist) were measured by transesophageal echocardiography at three different levels: ascending aorta (AA), distal aortic arch (Aarc) and descending aorta (DA). PWV was measured by Complior. AC was measured as the ratio of stroke volume to pulse pressure. CCA IMT was measured by ultrasonography in diastole. The Dist, IMT, and D of each aortic segment were introduced alternatively into the regression models. After controlling for age, sex, traditional risk factors and prevalent CV disease, AC showed a significant positive association with the distensibility of proximal aortic segments, but no significant association with properties of distal aorta; PWV showed a significant positive association with proximal aorta wall thickness and a negative association with distal aorta distensibility; CCA IMT was positively associated with distal aorta wall thickness, but not with any explored property of the proximal aorta. None of these relationships differed between younger or older, normotensive or hypertensive subjects. Non-invasive measures of large artery structure and function are not equivalent with respect to their relations with aortic properties, so that AC seems to reflect proximal aorta function, PWV proximal aorta structure and distal aorta function, and CCA IMT distal aorta structure. Future studies are needed to confirm whether these relations identify a common pathogenetic mechanism, which may be the target for new therapeutic strategies.

Aortic Root Anomalies of the Neck Presenting in Adults. Review of the Literature with Three Case Reports

Aortic Root Anomalies of the Neck Presenting in Adults. Review of the Literature with Three Case Reports

INVITED COMMENTARY

INVITED COMMENTARY

Aortic dissection: new frontiers in diagnosis and management: Part I: from etiology to diagnostic strategies.

Cardiovascular disease is the leading cause of death in most Western societies and is increasing steadily in many developing countries. Aortic diseases constitute an emerging share of the burden. New diagnostic imaging modalities, longer life expectancy in general, longer exposure to elevated blood pressure, and the proliferation of modern noninvasive imaging modalities have all contributed to the growing awareness of acute and chronic aortic syndromes. Despite recent progress in recognition of both the epidemiological problem and diagnostic and therapeutic advances, the cardiology community and the medical community in general are far from comfortable in understanding the spectrum of aortic syndromes and defining an optimal pathway to manage aortic diseases.1–13 This comprehensive review is organized in two parts, with a focus on the etiology, natural history, and classification (with vascular staging) of aortic wall disease in Part I and emphasis on therapeutic management and follow-up in Part II. Both parts may help to better integrate the complexities of acute aortic syndromes.

Guanine nucleotide-binding proteins in aortic smooth muscle from hypertensive rats.

To explore the hypothesis that altered vascular muscle signal transduction may underlie some of the vascular changes observed in hypertensive models, we measured expression of GTP-binding protein (G protein) alpha-subunits, Gs, G(i), and Gq, in aortic muscle of reduced renal mass and sham-operated rats and proximal and distal aortic segments from rats with interrenal aortic coarctation (IR-AC). G protein expression was measured by immunoblot analysis. When we probed aortic muscle membrane with G(i) and Gq alpha-subunit antibodies, we identified 41- and 42-kD immunoreactive proteins, respectively. Three immunoreactive bands specific to Gs alpha-subunit antibody were resolved. Immunoreactive blot densities were compared. In aortic muscle membrane of reduced renal mass rats (blood pressure, 148 +/- 7 mm Hg), we found significantly reduced Gs and G(i) blot densities compared with sham-operated controls (blood pressure, 99 +/- 12 mm Hg). There were no differences in Gq blot densities between reduced renal mass and control rats. Gs and G(i) blot densities were significantly lower in IR-AC proximal aortic segments (carotid pressure, 165 +/- 5 mm Hg) and distal aortic segments (femoral pressure, 121 +/- 4 mm Hg) than in aortas of sham-operated controls. In contrast, Gq expression was significantly increased in the high-pressure proximal aortic segments compared with low-pressure distal aortic segments from IR-AC rats. Thus, altered G protein expression occurs in aortic muscle from nongenetic rat models of hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Age-related modifications of aorta and coronaries in the rabbit: a morphological and morphometrical assessment

Aging seems to be related to various vascular diseases, such as dissecting aneurysm and atherosclerosis. The nature of the relationship between aging and these vascular diseases has not been completely clarified. The goal of this study was to investigate, using morphological and morphometrical methods, the age related modifications of the arterial wall in rabbits of thŕee different ages, evaluating separately two different vascular districts and the various aortic segments. Our results confirm that the most relevant age-related structural aortic changes were the increase of thickness, length, volume and diameter of the vessels, together with the development of an intimal thickening. The latter was diffuse in the aorta and focal in coronary vessels and it appears earlier in the aorta than in the coronaries, being absent in the coronaries of young rabbits. In addition, morphological and ultrastructural studies revealed the presence in aged rabbits of some marked intimal storage of a ground substance into intimal thickening of proximal aortic segments. Morphometric studies demonstrated an age-related decrease of aortic cellularity of tunica media and a parallel increase of the content of collagen and glycosaminoglycans, whereas elastin did not vary. The different relationships between cells and interstitial tissue occuring with aging are most probably a phenomenon of adaptation to the changing forces acting on the arterial wall and they might constitute the structural background of the increased arterial susceptibility to various noxae. Finally, the intimal storage of the ground substance, probably related to a functional disturbance of endothelium and or smooth muscle cells, may play an initiating role in atherogenesis.