Biomechanical characterization of normal and pathological human ascending aortic tissues via biaxial testing Experiment, constitutive modeling and finite element analysis

BACKGROUND

Aortic dissection and atherosclerosis are two common pathological conditions affecting the aorta. Aortic biomechanics are believed to be closely associated with the pathological development of these diseases. However, the biomechanical environment that predisposes the aortic wall to these pathological conditions remains unclear.

METHODS

Sixteen ascending aortic specimens were harvested from 16 human subjects and further categorized into three groups according to their disease states: aortic dissection group, aortic dissection with accompanied atherosclerosis group and healthy group. Experimental stress-strain data from biaxial tensile testing were used to fit the anisotropic Mooney-Rivlin model to determine material parameters. Computed tomography images or transesophageal echocardiography images were collected to construct computational models to simulate the stress/strain distributions in aortas at the pre-dissection state. Statistical analyses were performed to identify the biomechanical factors to distinguish three groups of aortic tissues.

RESULTS

Material parameters of anisotropic Mooney-Rivlin model were fitted with average R2 value 0.9749. The aortic diameter showed no significant difference among three groups. Changes of maximum and average stress values from minimum pressure to maximum pressure (△MaxStress and △AveStress) had significantly difference between dissection group and dissection with accompanied atherosclerosis group (p = 0.0201 and 0.0102). Changes of maximum and average strain values from minimum pressure to maximum pressure (△MaxStrain and △AveStrain) from dissection group were significant different from healthy group (p = 0.0171 and 0.0281).

CONCLUSION

Changes of stress and strain values during the cardiac cycle are good biomechanical factors for predicting potential aortic dissection and aortic dissection accompanied with atherosclerosis.

Impact of antithrombotic therapy on clinical outcomes in patients with type B acute aortic syndrome

Objective

Antithrombotic therapy has the potential to interfere with false lumen thrombosis. In type B acute aortic syndrome, the degree of false lumen thrombosis affects clinical outcomes. We aimed to explore the association of antithrombotic therapy with the prognosis of patients with type B acute aortic syndrome.

Methods

We reviewed 406 patients with type B acute aortic syndrome who were discharged alive with and without antithrombotic therapy. The primary outcome was aorta-related adverse events, defined as a composite of aorta-related death, aortic rupture, aortic repair, and progressive aortic dilation.

Results

Of the 406 patients, 64 (16%) were discharged with antithrombotic therapy and 342 (84%) were discharged without antithrombotic therapy. A total of 249 patients (61%) presented with intramural hematoma with complete thrombosis of the false lumen, and 157 patients (39%) presented with aortic dissection. During a median follow-up of 4.6 years, 32 patients (50%) in the antithrombotic group and 93 patients (27%) in the nonantithrombotic group had a primary outcome event. Cumulative incidence of aorta-related events at 1 and 3 years with death as the competing risk was higher in the antithrombotic group than in the nonantithrombotic group (19% ± 5% vs 9% ± 2% at 1 year and 40% ± 7% vs 17% ± 2% at 3 years, P < .001).

Conclusions

Antithrombotic therapy might be associated with an increased risk of aorta-related events in patients with type B acute aortic syndrome.

Integrated single-cell RNA-seq analysis reveals the vital cell types and dynamic development signature of atherosclerosis

Introduction: In the development of atherosclerosis, the remodeling of blood vessels is a key process involving plaque formation and rupture. So far, most reports mainly believe that macrophages, smooth muscle cells, and endothelial cells located at the intima and media of artery play the key role in this process. Few studies had focused on whether fibroblasts located at adventitia are involved in regulating disease process.

Methods and results: In this study, we conducted in-depth analysis of single-cell RNA-seq data of the total of 18 samples from healthy and atherosclerotic arteries. This study combines several analysis methods including transcription regulator network, cell-cell communication network, pseudotime trajectory, gene set enrichment analysis, and differential expression analysis. We found that SERPINF1 is highly expressed in fibroblasts and is involved in the regulation of various signaling pathways.

Conclusion: Our research reveals a potential mechanism of atherosclerosis, SERPINF1 regulates the formation and rupture of plaques through the Jak-STAT signaling pathway, which may provide new insights into the pathological study of disease. Moreover, we suggest that SRGN and IGKC as potential biomarkers for unstable arterial plaques.

A Novel Serum Biomarker Model to Discriminate Aortic Dissection from Coronary Artery Disease

Background

The misdiagnosis of aortic dissection (AD) can lead to a catastrophic prognosis. There is currently a lack of stable serological indicators with excellent efficacy for the differential diagnosis of AD and coronary artery disease (CAD). A recent study has shown an association between AD and iron metabolism. Thus, we investigated whether iron metabolism could discriminate AD from CAD.

Methods

This retrospective and multicenter cross-sectional study investigated the efficacy of biomarkers of iron metabolism for the differential diagnosis of AD. We collected biomarkers of iron metabolism, liver function, kidney function, and other biochemistry test, and further, logistic regression analysis was applied.

Results

Between Oct. 8, 2020, and Mar. 1, 2021, we recruited 521 patients diagnosed with AD, CAD, and other cardiovascular diseases (OCDs) with the main symptoms of chest and back pain and assigned them to discovery set (n = 330) or validation set (n = 191). We found that six serum biomarkers, including serum iron, low-density lipoprotein, uric acid, transferrin, high-density lipoprotein, and estimated glomerular filtration rate, can serve as a novel comprehensive indicator (named FLUTHE) for the differential diagnosis of AD and CAD with a sensitivity of 0.954 and specificity of 0.905 to differentially diagnose AD and CAD more than 72 h past symptom onset.

Conclusion

Our findings provide insight into the role of iron metabolism in diagnosing and distinguishing AD, which might in the future be a key component in AD diagnosis. Furthermore, we establish a novel model named "FLUTHE" with higher efficiency, safety, and economy, especially for patients with chest pain for more than 72 h.

Association of Physical Activity with Aortic Disease in Japanese Men and Women: The Japan Collaborative Cohort Study

AIMS

Evidence of the effects of physical activity on mortality from aortic diseases, especially in Asian populations, remains limited. This study aimed to examine these effects using data from a large long-term cohort study of Japanese men and women.

METHODS

Between 1988 and 1990, 32,083 men and 43,454 women in Japan, aged 40-79 years with no history of coronary heart disease, stroke, aortic diseases, or cancer, filled in questionnaires on time spent walking and participating in sports and were followed up until 2009. Multivariable hazard ratios (HRs) with 95% confidence intervals (CIs) of aortic disease mortality and its types (aortic aneurysm and dissection) according to the time spent walking and participating in sports were calculated after adjusting for potential confounding factors using the Cox proportional hazards model.

RESULTS

During a median follow-up of 19.1 years, a total of 173 deaths from aortic disease (91 cases of aortic dissection and 82 of aortic aneurysm) were documented. Sports participation time was inversely associated with the risk of death from aortic aneurysm: the multivariable HRs (95% CIs) were 0.68 (0.40-1.16) for ＜1 h/week, 0.50 (0.19-1.35) for 3-4 h/week, and 0.31 (0.10-0.93) for ≥ 5 h/week (p for trend=0.23) compared with 1-2 h/week. The time spent walking was not associated with death from aortic aneurysm, dissection, and total aortic diseases.

CONCLUSIONS

Greater time spent in sports participation was associated with a reduced risk of mortality from aortic aneurism in the Japanese population. Further studies are needed to investigate the relationship between physical activity and aortic dissection.

Blood Pressure, Hypertension, and the Risk of Aortic Dissection Incidence and Mortality: Results From the J-SCH Study, the UK Biobank Study, and a Meta-Analysis of Cohort Studies

BACKGROUND

Hypertension or elevated blood pressure (BP) is an important risk factor for aortic dissection (AD); however, few prospective studies on this topic have been published. We investigated the association between hypertension/elevated BP and AD in 2 cohorts and conducted a meta-analysis of published prospective studies, including these 2 studies.

METHODS

We analyzed data from the J-SHC study (Japan-Specific Health Checkups) and UK Biobank, which prospectively followed up 534 378 and 502 424 participants, respectively. Multivariable Cox regression was used to estimate hazard ratios and 95% CIs for the association of hypertension/elevated BP with AD incidence in the UK Biobank and AD mortality in the J-SHC Study. In the meta-analysis, summary relative risks were calculated with random-effects models. A potential nonlinear dose-response relationship between BP and AD was tested with fractional polynomial models, and the best-fitting second-order fractional polynomial regression model was determined.

RESULTS

In the J-SHC study and UK Biobank, there were 84 and 182 ADs during the 4- and 9-year follow-up, and the adjusted hazard ratios of AD were 3.57 (95% CI, 2.17-6.11) and 2.68 (95% CI, 1.78-4.04) in hypertensive individuals, 1.33 (95% CI, 1.05-1.68) and 1.27 (95% CI, 1.11-1.48) per 20-mm Hg increase in systolic BP (SBP), and 1.67 (95% CI, 1.40-2.00) and 1.66 (95% CI, 1.46-1.89) per 10-mm Hg increase in diastolic BP (DBP), respectively. In the meta-analysis, the summary relative risks were 3.07 (95% CI, 2.15-4.38, I2=76.7%, n=7 studies, 2818 ADs, 4 563 501 participants) for hypertension and 1.39 (95% CI, 1.16-1.66, I2=47.7%, n=3) and 1.79 (95% CI: 1.51-2.12, I2 = 57.0%, n=3) per 20-mm Hg increase in SBP and per 10-mm Hg increase in DBP, respectively. The AD risk showed a strong, positive dose-response relationship with SBP and even more so with DBP. The risk of AD in the nonlinear dose-response analysis was significant at SBP >132 mm Hg and DBP >75 mm Hg.

CONCLUSIONS

Hypertension and elevated SBP and DBP are associated with a high risk of AD. The risk of AD was positively dose dependent, even within the normal BP range. These findings provide further evidence for the optimization of BP to prevent AD.

Higher Plasma Aldosterone Concentrations Are Associated With Elevated Risk of Aortic Dissection and Aneurysm: a Case-Control Study

BACKGROUND

Animal models demonstrate circulating aldosterone leads to aortic dissection and aneurysm, whereas data from humans are lacking. Therefore, we aimed to examine the associations of plasma aldosterone concentrations (PAC) with aortic dissection and aneurysm.

METHODS

We identified patients with aortic dissection and aneurysm with assessed PAC before disease onset from hospital-based electronic database and set as case group. Simultaneously, age and gender-matched cohort with PAC measurement whereas without aortic dissection and aneurysm were selected as control group using ratio of 1:4. Multi-variable logistic regression analysis was used to assess the relationship of PAC with aortic dissection and aneurysm.

RESULTS

Totally, 133 cases and 531 controls (all hypertensive) were enrolled between 2004 and 2021, with 77.9% men, mean age of 55.5 years and PAC of 13.9 ng/dL. Case group showed significantly higher PAC(14.51 versus 13.65 ng/dL, P=0.012) than did control group. In logistic regression analysis, higher PAC exhibited 1.68-fold higher odds (95% CI, 1.14-2.48, P=0.008) for presence of aortic dissection and aneurysm, significant in adjusted model (odds ratio, 1.69 [95% CI, 1.11-2.57], P=0.015). In stratified analysis, the association between the 2 was observed in women of all ages and in men with coronary artery disease. Sensitivity analysis by excluding those under interfering agents at PAC measurement and those with primary aldosteronism did not change the relationship of the 2.

CONCLUSIONS

Higher PAC is associated with the increased odd for aortic dissection and aneurysm in patients with hypertension, even in the absence of primary aldosteronism, implying that PAC might be a target for prevention.

Resistin and Cardiovascular Disease: A Review of the Current Literature Regarding Clinical and Pathological Relationships

Serum resistin, mainly secreted by the bone marrow, monocytes, and macrophages, contributes to many processes, including endothelial dysfunction, Vascular Smooth Muscle Cell (VSMC) proliferation, and atherothrombosis demonstrating effects on the development of hypertension and Coronary Artery Disease (CAD). Previously published clinical studies have shown that plasma resistin levels are significantly associated with cardiovascular disease risk factors and adverse clinical outcomes associated with the condition. Resistin is associated with vascular smooth muscle cell dysfunction in vitro, most plausibly due to its relationship with oxidative stress in advanced atherosclerosis whereas in vivo studies have shown resistin to be associated with intimal hyperplasia. We aimed to summarize the role of resistin on cardiovascular disease (CVD), as we could not find any review focused on the role of resistin on CVD.

Patterns of Immune Infiltration and the Key Immune-Related Genes in Acute Type A Aortic Dissection in Bioinformatics Analyses

Background

Immune-inflammatory mechanisms contribute greatly to the complex process leading to type A aortic dissection (TAAD). This study aims to explore immune infiltration and key immune-related genes in acute TAAD.

Methods

ImmuCellAI algorithm was applied to analyze patterns of immune infiltration in TAAD samples and normal aortic vessel samples in the GSE153434 dataset. Differentially expressed genes (DEGs) were screened. Immune-related genes were obtained from overlapping DEGs of GSE153434 and immune genes of the ImmPort database. The hub genes were obtained based on the protein–protein interaction (PPI) network. The hub genes in TAAD were validated in the GSE52093 dataset. The correlation between the key immune-related genes and infiltrating immune cells was further analyzed.

Results

In the study, the abundance of macrophages, neutrophils, natural killer T cells (NKT cells), natural regulatory T cells (nTreg), T-helper 17 cells (Th17 cells) and monocytes was increased in TAAD samples, whereas that of dendritic cells (DCs), CD4 T cells, central memory T cells (Tcm), mucosa associated invariant T cells (MAIT cells) and B cells was decreased. Interleukin 6 (IL-6), C-C motif chemokine ligand 2 (CCL2) and hepatocyte growth factor (HGF) were identified and validated in the GSE52093 dataset as the key immune-related genes. Furthermore, IL-6, CCL2 and HGF were correlated with different types of immune cells.

Conclusion

In conclusion, several immune cells such as macrophages, neutrophils, NKT cells, and nTreg may be involved in the development of TAAD. IL-6, CCL2 and HGF were identified and validated as the key immune-related genes of TAAD via bioinformatics analyses. The key immune cells and immune-related genes have the potential to be developed as targets of prevention and immunotherapy for patients with TAAD.

State of the Art Review: Surgical Treatment of Acute Type A Aortic Dissection

Acute type A aortic dissection (ATAAD) is a life-threatening event that requires immediate surgical treatment. Improvements in surgical treatment, graft technology, organ protection and imaging techniques have led to improved clinical outcomes. Individualized treatment concepts have emerged based on more advanced planning tools that allow for a tailored approach even in complex situations such as multi-level malperfusion. This review provides an overview of the current surgical treatment of ATAAD, focusing on new disease classifications, preoperative computed tomography angiography (CTA) assessment, new prosthesis and stent technologies, and organ-protection strategies.

Non-O blood group is associated with lower risk of in-hospital mortality in non-surgically managed patients with type A aortic dissection

BACKGROUND

The association between different ABO blood groups and mortality of aortic dissection (AD) remains controversial. This study aimed to examine whether different ABO blood groups affect the prognosis of AD.

METHODS

Demographic and clinical data were collected from 877 patients diagnosed with AD from 2015 to 2019 in the First Affiliated Hospital of Shantou University Medical College. The association between in-hospital mortality of AD patients and ABO blood group was analyzed using Cox proportional hazards regression models.

RESULTS

This retrograde cohort study demonstrated that for 877 patients, male gender, non-O blood group, Stanford type B AD (TBAD), higher presenting systolic and diastolic blood pressure, and being a recipient of aortic arch replacement surgery (surgery) or endovascular stent-graft implantation (stent-graft) were associated with decreased in-hospital mortality of AD. In Cox proportional hazards models, non-O blood group was associated with lower risk of early mortality regardless of adjustment (HR = 0.668, 95% confidence interval [CI] 0.473-0.944 before adjustment, HR = 0.662, 95% CI 0.468-0.935 after adjustment for age and sex, and HR = 0.641, 95% CI 0.453-0.906 after adjustment for AD types, SBP and surgery). Further analyses revealed that for patients diagnosed with type A AD (TAAD), non-O blood group renders a significant 34.3% decrease in the risk of in-hospital mortality compared with blood group O. Specifically, this difference in mortality risk was found among TAAD patients who did not undergo surgery (HR = 0.579, 95% CI 0.377-0.889), rather than those who did. There was no significant difference in early mortality for patients with TBAD, whether or not stent-grafts were implanted.

CONCLUSIONS

Non-O blood type decreases the risk of in-hospital mortality, especially for TAAD, in AD patients without surgical intervention. More attention must be paid to blood type O TAAD patients without surgical interventions, and early surgical intervention may be an effective means to decrease in-hospital mortality of TAAD.

Association of renal cyst and type A acute aortic dissection with hypertension

Background

Type A acute aortic dissection (TA-AAD) has high mortality, with 50% of patients dying before hospital admission. Hypertension is the most common comorbidity for acute aortic dissection, and effective antihypertensive therapy is still unable to predict the risk of aortic rupture at the medium- and long-term stages. While the presence of renal cyst has been found to increases the risk of thoracic aortic disease, the correlation between renal cyst and TA-AAD with hypertension remains poorly understood. Thus, this study aimed to determine the relationship of renal cyst and TA-AAD with hypertension.

Methods

A retrospective analysis was performed in 464 hypertension patients from August 2014 to August 2019. A total of 230 TA-AAD patients were enrolled in the AD with hypertension group (age 53.79±11.31 years, male 90.87%), and matched by age, sex, and hypertension control to 234 patients without TA-AAD who were enrolled in the non-AD with hypertension group. Patients were divided into three subgroups according to the numbers of renal cysts: no renal cyst, single renal cyst, and multiple renal cysts.

Results

In this study, the AD with hypertension group had significantly more single renal cyst and multiple renal cyst cases than did the non-AD with hypertension group. The mean age of the multiple renal cyst subgroup was significantly older than that of the single renal cyst subgroup (57.25±13.00 vs. 51.57±10.75 years) in the AD with hypertension group. There was significantly different distribution of dissection starting points and dissection ending points across three renal cyst subgroups. Multivariate logistic regression analysis indicated that having no renal cyst significantly decreased the risk of TA-AAD in middle-aged and elderly patents, but showed no correlations with those of younger ages. Single renal cyst status also significantly decreased the risk of TA-AAD in elderly patients [odds ratio (OR) =0.129, 95% confidence interval (CI): 0.029–0.575, P=0.007].

Conclusions

Renal cyst status correlates with the risk of TA-AAD with hypertension in middle-aged and elderly patients, and exhibits different degrees of vascular lesion in aortic dissection. We therefore suggest that different antihypertensive standards should be adopted in different renal cyst status to more effectively prevent aortic dissection.

Integrative bioinformatics analysis of miRNA and mRNA expression profiles and identification of associated miRNA-mRNA network in aortic dissection

BACKGROUND

Aortic dissection (AD) is one of the most lethal cardiovascular diseases. The aim of this study was to identify core genes and pathways revealing pathogenesis in AD.

METHODS

We screened differentially expressed mRNAs and miRNAs using mRNA and miRNA expression profile data of AD from Gene Expression Omnibus. Then functional and pathway enrichment analyses of differential expression genes (DEGs) was performed utilizing the database for annotation, visualization, and integrated discovery (DAVID). Target genes with differential expression miRNAs (DEMIs) were predicted using the miRWalk database, and the intersection between these predictions and DEGs was selected as differentially expressed miRNA-target genes. In addition, a protein-protein interaction (PPI) network and miRNA-mRNA regulatory network were constructed.

RESULTS

In total, 130 DEGs and 47 DEMIs were identified from mRNA and miRNA microarray, respectively, and 45 DEGs were DEMI-target genes. The PPI and miRNA-mRNA network included 79 node genes and 74 node genes, respectively, while 23 hub genes and 2 hub miRNAs were identified. The DEGs, PPI and modules differential expression miRNA-target genes were all mainly enriched in cell cycle, cell proliferation and cell apoptosis signaling pathways.

CONCLUSION

Taken above, the study reveals some candidate genes and pathways potentially involving molecular mechanisms of AD. These findings provide a new insight for research and treatment of AD.

Plasma Resistin Levels in Patients with Acute Aortic Dissection: A Propensity Score-Matched Observational Case-Control Study

Background

The aim of this observational case-control study was to compare the levels of plasma resistin between patients with acute aortic dissection and matched controls, and to use propensity score matching (PSM) to reduce case selection bias and clinical confounders.

Material/Methods

With the use of PSM, this study included 43 pairs of patients with acute aortic dissection (type-A and type-B dissection) and matched controls. Plasma resistin levels and other laboratory parameters were compared between the two groups, including white blood cell (WBC) count, glucose, high sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and D-dimer. The correlations between resistin and other laboratory parameters were evaluated in patients with acute aortic dissection.

Results

Following PSM adjustment for clinical variables, including age, sex, body mass index, smoking, alcohol drinking, hypertension, diabetes mellitus, coronary heart disease and stroke, plasma resistin levels were significantly increased in patients with acute aortic dissection when compared with controls (35.2±13.8 vs. 18.4±9.1 ng/ml) (p<0.001). WBC counts, and levels of glucose, hs-CRP, IL-6, TNF-α and D-dimer were also significantly increased in the patients with aortic dissection compared with the control group. After adjustment for these variables, the association between plasma resistin levels and acute aortic dissection remained significant (OR, 1.114; 95% CI, 1.036–1.224) (p<0.001). Plasma resistin levels was positively correlated with WBC count (r=0.368, p=0.015), hs-CRP (r=0.359, p=0.022), IL-6 (r=0.306, p=0.046) and TNF-α levels (r=0.315, p=0.040) in patients with acute aortic dissection.

Conclusions

Acute aortic dissection is associated with elevated levels of plasma resistin and other pro-inflammatory cytokines. Plasma resistin levels is positively associated with other pro-inflammatory cytokines in acute aortic dissection.

Impact of aortic plaque on progression rate and prognosis of aortic stenosis

BACKGROUNDS

Patients with aortic stenosis (AS) have a high prevalence of aortic plaque. However, no data exist regarding the clinical significance and prognostic value of aortic plaque in AS patients. This study examines the impact of aortic plaque on the rate of progression and clinical outcomes of AS.

METHODS

We retrospectively investigated 1812 transesophageal echocardiographic examinations between 2008 and 2015. We selected 100 consecutive patients (mean age; 75.1±7.4years) who showed maximal aortic jet velocity (AV-Vel) ≥2.0m/s by transthoracic echocardiography (TTE) and received follow-up TTE (mean follow-up duration 25±17months), and the mean progression rate of AV-Vel was calculated. Clinical and echocardiographic characteristics, including severity of aortic plaque, and cardiac events were examined.

RESULTS

At initial TTE, mean AV-Vel was 3.68±0.94m/s and mean aortic valve area 0.98±0.32cm². Mean progression rate of AV-Vel was 0.41m/s/year in 38 patients with severe aortic plaque, and -0.03m/s/year in the remaining 62 patients without severe aortic plaque. Severe aortic plaque (odds ratio[OR], 8.32) and hemodialysis (OR, 6.03) were independent predictors of rapid progression. The event-free survival rate at 3years was significantly lower in patients with severe aortic plaque than in those without (52% vs 82%, p=0.002). Severe aortic plaque (hazard ratio[HR], 2.89) and AV-Vel at initial TTE (HR, 3.28) were identified as independent predictors of cardiac events.

CONCLUSION

Severe aortic plaque was a predictor of rapid progression and poor prognosis in AS patients. Evaluation of aortic plaque provides additional information regarding surgical scheduling and follow-up.

Sonographic Characterization of Arterial Dissections in Takayasu Arteritis

OBJECTIVES

Takayasu arteritis is a relatively rare chronic nonspecific form of large-vessel vasculitis in which the involved vessels develop stenoses, occlusions, dilatations or aneurysms, and dissections. Dissections of the arteries in patients with Takayasu arteritis are not well understood. In this study, we explored the sonographic characterization of these rare complications secondary to Takayasu arteritis.

METHODS

We evaluated arterial dissections in 72 patients with a clinical diagnosis of Takayasu arteritis by vascular sonography and transthoracic echocardiography. We analyzed the dissection distribution and morphologic characteristics of the dissected intima/layer and lumen of the involved vessels.

RESULTS

Twelve of 72 patients had arterial dissections, in whom 16 dissected segments were identified. The involved arteries included the carotid, subclavian, vertebral, brachial, celiac, and femoral arteries, aortic arch, and abdominal aorta. The dissection lesions occurred at any age and coexisted with the aforementioned injuries. Evaluation of the dissected intima/layer and the involved lumen by sonography was technically complicated. The morphologic characteristics of the dissected intimae and involved lumens were complex, with most of the dissected intimae/layers having the characteristic "macaroni" sign in the arterial wall. High-frequency and high-resolution sonography, color Doppler flow imaging, and other techniques were useful in elucidating greater lesion details.

CONCLUSIONS

Arterial dissections in Takayasu arteritis can involve any anatomic vessel location and have complex morphologic characteristics. Sonography is the optimal technique for diagnosis and follow-up of patients with Takayasu arteritis and dissections.

Expression of matrix metalloproteinase-12 in aortic dissection

BACKGROUND

Aortic dissection(AD) is an acute process of large blood vessels characterized by dangerous pathogenic conditions and high disability and high mortality. The pathogenesis of AD remains debated. Matrix metalloproteinase-12 (MMP-12) participates in many pathological processes such as abdominal aortic aneurysm, atherosclerosis, emphysema and cancer. However, this elastase has rarely been assessed in the presence of AD. The aim of the present study was to investigate the expression of MMP-12 in aortic tissue so as to offer a better understanding of the possible mechanisms of AD.

METHODS

The protein expression levels of MMP-12 were analyzed and compared in aorta tissue and the blood serum samples by reverse transcription polymerase chain reaction(RT-PCR), Western blotting, immuno-histochemistry, fluorescence resonance energy transfer ( FRET ) activity assay and enzyme-linked immuno sorbent assay ( ELISA ), respectively. Ascending aorta tissue specimens were obtained from 12 patients with an acute Stanford A-dissection at the time of aortic replacement, and from 4 patients with coronary artery disease (CAD) undergoing coronary artery bypass surgery. Meanwhile, serum samples were harvested from 15 patients with an acute Stanford A-dissection and 10 healthy individuals who served as the control group.

RESULTS

MMP-12 activity could be detected in both AD and CAD groups, but the level in the AD group was higher than those in the CAD group (P < 0.05). MMP-12 proteolysis existed in both serum samples of the AD and healthy groups, and the activity level in the AD group was clearly higher than in the healthy group (P < 0.05). For AD patients, MMP-12 activity in serum was higher than in the aorta wall (P < 0.05). MMP-12 activity in the aortic wall tissue can be inhibited by MMP inhibitor v (P < 0.05).

CONCLUSION

The present study directly demonstrates that MMP-12 proteolytic activity exists within the aorta specimens and blood samples from aortic dissection patients. MMP-12 might be of potential relevance as a clinically diagnostic tool and therapeutic target in vascular injury and repair.

Acute aortic dissection in China

The clinical profiles and outcomes of acute aortic dissection (AAD) have not been evaluated in China. We retrospectively analyzed, from January 1, 2008 to December 31, 2011, the data from 1,812 patients (mean age 51.1 ± 10.9 years; 77.5% men) with AAD (726 with type A and 1,086 with type B) from 19 large hospitals. Most patients had hypertension and presented with an abrupt onset of chest and/or back pain. Patients with type A AAD were more likely to present with typical symptoms and signs. Computed tomography was the most common initial imaging modality, used in 76.3% of patients with an AAD. The overall in-hospital mortality rate was 17.7%, with most of the deaths occurring within the first week. Surgery was used in 75.3% of patients with type A AAD. The mortality in this cohort was 33.8%. Endovascular treatment was performed in 76.1% of patients with type B AAD. The mortality rate was 2.2%. Multivariate analysis showed that hypertension (odds ratio 2.80, p <0.001), Marfan syndrome (odds ratio 1.76, p = 0.017), anterior chest pain (odds ratio 1.62, p = 0.004), abdominal pain (odds ratio 1.51, p = 0.041), migrating pain (odds ratio 1.56, p = 0.04), and arch vessel involvement (odds ratio 1.70, p <0.001) were predictive factors for increased in-hospital mortality in patients with an AAD. In conclusion, our study has provided insight into the current profiles and outcomes of AAD in China. This knowledge might be useful for clinicians when diagnosing and treating these patients.

Reduction of the PaO2/FiO2 ratio in acute aortic dissection – relationship between the extent of dissection and inflammation –

BACKGROUND

Acute aortic dissection (AAD) often accompanies acute respiratory failure. The aim of this study was to clarify the relationship between the incidence of oxygenation impairment and the extent of distal type AAD.

METHODS AND RESULTS

A total of 49 patients with medically treated distal type AAD were retrospectively examined. AAD% was defined as the percentage of the volume of false lumen to that of aorta in the descending aorta. AAD% was measured by computed tomography. C-reactive protein (CRP) levels, white blood cell (WBC) counts, body temperature and arterial partial pressure of oxygen/fraction of inspired oxygen (PaO(2)/FiO(2)) ratio were measured serially. Oxygenation impairment was defined as a PaO(2)/FiO(2) ratio ≤ 200. This occurred in 19 patients (39%). In patients with oxygenation impairment, AAD% (50.8 ± 10.9% vs 28.0 ± 11.9%, P<0.001), peak CRP levels (15.2 ± 6.5 mg/dl vs 9.6 ± 4.6 mg/dl, P<0.001), peak WBC counts (13,600 ± 3,700/µl vs 10,400 ± 2,800 /µl, P=0.001) and body temperature (38.1 ± 0.5°C vs 37.8 ± 0.4°C, P=0.045) were higher than those without oxygenation impairment. It was found that there were inverse correlations between the PaO(2)/FiO(2) ratio and AAD% (r=-0.604, P<0.001), and between peak CRP levels and the PaO(2)/FiO(2) ratio (r=-0.635, P<0.001). Multivariate analysis demonstrated that the only independent predictor of oxygenation impairment was AAD% (odds ratio, 1.323; 95% confidence interval, 1.035-1.691, P=0.026).

CONCLUSIONS

Respiratory failure in AAD appears to be closely correlated with the amount of aortic injury, possibly mediated by the magnitude of the systemic inflammatory reaction to the aortic injury.

Genetic analysis of young adult patients with aortic disease not fulfilling the diagnostic criteria for Marfan syndrome

BACKGROUND

Although the existence of the young patients with aortic disease not fulfilling the diagnostic criteria for Marfan syndrome (MFS) has been known, the etiology of their disease has not yet been elucidated. The purpose of the present study was to elucidate the genetic and clinical features of the young patients with aortic disease not having MFS.

METHODS AND RESULTS

Eighty young adult patients with aortic disease were examined. They were divided into a definite MFS (n=51) and a non-definite MFS group (n=29) according to the Ghent nosology. Clinical and genetic characteristics were compared between the 2 groups. Among 29 non-definite MFS probands, 1 (3%) FBN1, 2 (7%) TGFBR1, and 3 (10%) TGFBR2 mutations were found, and 4 ACTA2 mutations were found in the 23 probands examined without FBN1, TGFBR1, or TGFBR2 mutations. In total, more than 10 out of 29 (34%) probands in the non-definite MFS group were associated with genetic mutations. Skeletal involvement was less frequent in the non-definite than in the definite MFS group (7% vs 82%, P<0.01).

CONCLUSIONS

In the probands with aortic diseases in young who cannot be diagnosed with MFS, mutations other than FBN1 mutations accounted for at least one-third of all causes of aortic disease.

Increases of cardiac troponin in conditions other than acute coronary syndrome and heart failure

BACKGROUND

Although cardiac troponin (cTn) is a cornerstone marker in the assessment and management of patients with acute coronary syndrome (ACS) and heart failure (HF), cTn is not diagnostically specific for any single myocardial disease process. This narrative review discusses increases in cTn that result from acute and chronic diseases, iatrogenic causes, and myocardial injury other than ACS and HF.

CONTENT

Increased cTn concentrations have been reported in cardiac, vascular, and respiratory disease and in association with infectious processes. In cases involving acute aortic dissection, cerebrovascular accident, treatment in an intensive care unit, and upper gastrointestinal bleeding, increased cTn predicts a longer time to diagnosis and treatment, increased length of hospital stay, and increased mortality. cTn increases are diagnostically and prognostically useful in patients with cardiac inflammatory diseases and in patients with respiratory disease; in respiratory disease cTn can help identify patients who would benefit from aggressive management. In chronic renal failure patients the diagnostic sensitivity of cTn for ACS is decreased, but cTn is prognostic for the development of cardiovascular disease. cTn also provides useful information when increases are attributable to various iatrogenic causes and blunt chest trauma.

SUMMARY

Information on the diagnostic and prognostic uses of cTn in conditions other than ACS and heart failure is accumulating. Although increased cTn in settings other than ACS or heart failure is frequently considered a clinical confounder, the astute physician must be able to interpret cTn as a dynamic marker of myocardial damage, using clinical acumen to determine the source and significance of any reported cTn increase.