The biomechanical rupture risk assessment (BRRA) of abdominal aortic aneurysms (AAA) has higher sensitivity than maximal diameter criterion (DSEX) but its estimation is time-consuming and relies on an uncertain estimation of wall thickness. The aim of this study is to test tension-based criterion in the BRRA of AAA which removes the necessity of wall thickness measurement and should be faster. For that, we retrospectively analyzed 99 patients with intact AAA (25 females). Nineteen of them experienced a rupture later. BRRA was performed with wall tension PRRIT as a primary criterion. The ability of criterion to separate intact and ruptured AAAs at 1,3,6,9 and 12 months was estimated. Next, the receiver operating characteristics and the percentage of true negative cases for a different time to an outcome were estimated. Finally, the computational time was recorded. The results were compared to stress-based criterion PRRI and DSEX which served as a reference. All three criterions were able to discriminate between intact and ruptured AAAs up to 9 months (p < 0.05) while none of them could do for a 12 month prediction. PRRIT exhibited a significantly higher percentage of true negatives for 12 and 9 month predictions (45 % and 20 % respectively) and similar to other criteria for other prediction times. The mean computational time for estimating PRRIT was 19 h per patient compared to 67 h for PRRI. The tension- based BRRA of AAA leads to better outcomes for a 9 and 12 month prediction while the computational time drops by more than 70 % compared to PRRI.

• MeSH
• aneurysma břišní aorty * patofyziologie   diagnostické zobrazování   MeSH
• biomechanika MeSH
• hodnocení rizik metody   MeSH
• lidé středního věku MeSH
• lidé MeSH
• modely kardiovaskulární MeSH
• retrospektivní studie MeSH
• ruptura aorty * patofyziologie   diagnostické zobrazování   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

OBJECTIVE: Several studies of biomechanical rupture risk assessment (BRRA) showed its advantage over the diameter criterion in rupture risk assessment of abdominal aortic aneurysm (AAA). However, BRRA studies have not investigated the predictability of biomechanical risk indices at different time points ahead of rupture, nor have they been performed blinded for biomechanical analysts. The objective of this study was to test the predictability of the BRRA method against diameter-based risk indices in a quasi-prospective patient cohort study. METHODS: In total, 12 women and 31 men with intact AAAs at baseline have been selected retrospectively at two medical centers. Within 56 months, 19 cases ruptured, whereas 24 cases remained intact within 2 to 56 months. This outcome was kept confidential until all biomechanical activities in this study were finished. The biomechanical AAA rupture risk was calculated at baseline using high-fidelity and low-fidelity finite element method models. The capability of biomechanics-based and diameter-based risk indices to predict the known outcomes at 1 month, 3 months, 6 months, 9 months, and 12 months after baseline was validated. Besides common cohort statistics, the area under the curve (AUC) of receiver operating characteristic curves has been used to grade the different rupture risk indices. RESULTS: Up to 9 months ahead of rupture, the receiver operating characteristic analysis of biomechanics-based risk indices showed a higher AUC than diameter-based indices. Six months ahead of rupture, the largest difference was observed with an AUC of 0.878 for the high-fidelity biomechanical risk index, 0.859 for the low-fidelity biomechanical risk index, 0.789 for the diameter, and 0.821 for the sex-adjusted diameter. In predictions beyond 9 months, none of the risk indices proved to be superior. CONCLUSIONS: High-fidelity biomechanical modeling improves the predictability of AAA rupture. Asymptomatic AAA patients with high biomechanical AAA rupture risk indices have an increased risk of rupture. Integrating biomechanics-based diagnostic indices may significantly decrease the false-positive rate in AAA treatment. CLINICAL RELEVANCE: Rupture of abdominal aortic aneurysm (AAA) is the tenth leading cause of death in men older than 60 years; however, the currently used maximal diameter criterion has a high false-positive rate. In this study, we have compared this criterion with biomechanical rupture risk assessment on the unique data set of 43 asymptomatic AAAs, of which 19 ruptured later. Moreover, the AAA outcome was blinded to the operator for the first time. Our data demonstrated that the biomechanical rupture risk assessment is superior to maximal diameter in predicting AAA rupture up to 9 months ahead and significantly decreases the false-positive rate.

• MeSH
• aneurysma břišní aorty diagnóza   epidemiologie   patofyziologie   MeSH
• asymptomatické nemoci MeSH
• biomechanika MeSH
• hodnocení rizik metody   MeSH
• kohortové studie MeSH
• lidé středního věku MeSH
• lidé MeSH
• prediktivní hodnota testů MeSH
• retrospektivní studie MeSH
• ruptura aorty diagnóza   epidemiologie   patofyziologie   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• senzitivita a specificita MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

A rupture risk assessment is critical to the clinical treatment of abdominal aortic aneurysm (AAA) patients. The biomechanical AAA rupture risk assessment quantitatively integrates many known AAA rupture risk factors but the variability of risk predictions due to model input uncertainties remains a challenging limitation. This study derives a probabilistic rupture risk index (PRRI). Specifically, the uncertainties in AAA wall thickness and wall strength were considered, and wall stress was predicted with a state-of-the-art deterministic biomechanical model. The discriminative power of PRRI was tested in a diameter-matched cohort of ruptured (n = 7) and intact (n = 7) AAAs and compared to alternative risk assessment methods. Computed PRRI at 1.5 mean arterial pressure was significantly (p = 0.041) higher in ruptured AAAs (20.21(s.d. 14.15%)) than in intact AAAs (3.71(s.d. 5.77)%). PRRI showed a high sensitivity and specificity (discriminative power of 0.837) to discriminate between ruptured and intact AAA cases. The underlying statistical representation of stochastic data of wall thickness, wall strength and peak wall stress had only negligible effects on PRRI computations. Uncertainties in AAA wall stress predictions, the wide range of reported wall strength and the stochastic nature of failure motivate a probabilistic rupture risk assessment. Advanced AAA biomechanical modelling paired with a probabilistic rupture index definition as known from engineering risk assessment seems to be superior to a purely deterministic approach.

• MeSH
• aneurysma břišní aorty * patologie   patofyziologie   MeSH
• biomechanika MeSH
• hodnocení rizik MeSH
• lidé MeSH
• modely kardiovaskulární * MeSH
• ruptura aorty * patologie   patofyziologie   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Abdominal aortic aneurysms (AAAs) involve complex interplays between inflammatory and biomechanical factors that can be elucidated with anatomical and functional imaging. Although AAA size has been well-established in the literature to correlate with risk of rupture (and subsequent need for vascular intervention), there are other less-well-known characteristics about AAAs that also contribute to higher risk of rupture. This review focuses on biomechanical, radiological, and epidemiological characteristics of AAAs that are associated with higher rupture risk. For clinicians, knowing and considering a wide variety of risk factors in addition to AAA size is important to initiate early and proper intervention for AAA repair. Although there is no official quantitative risk score of AAA rupture risk that takes other non-size-related variables into account, if clinicians are aware of these other parameters, it is hoped that intervention can be appropriately performed for higher-risk AAAs that have not met the size-threshold for elective repair.

• MeSH
• aneurysma břišní aorty diagnóza   epidemiologie   patologie   patofyziologie   MeSH
• hodnocení rizik MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   MeSH
• počítačová rentgenová tomografie metody   MeSH
• pozitronová emisní tomografie metody   MeSH
• rizikové faktory MeSH
• ruptura aorty diagnóza   epidemiologie   patologie   patofyziologie   MeSH
• trombóza komplikace   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

Ruptura je nejzávažnější a smrtící komplikací aneurysmatu abdominální aorty. I přes zlepšení situace za posledních 50 let jsou ruptury aneurysmat abdominální aorty spojeny s vysokou mortalitou. Mortalita z ruptury aneurysmatu abdominální aorty je 90 %, zejména se zahrnutím pacientů, kteří zemřou dříve než jsou transportováni do nemocnice. Na druhé straně počet aneurysmat abdominální aorty se za posledních 20 let výrazně zvýšil. Jeden z důvodů je stárnutí populace ve většině zemí, a proto počet degenerativních AAA se zvyšuje. Stejně tak je tomu u pacientů s rupturou aneurysmatu břišní aorty. Věk nesmí být důvodem odmítnutí léčby. Je nutné nalézt optimální léčebné možnosti. Následující práce je založena na analýze literatury včetně součaných doporučení, ale také na významných zkušenostech naší kliniky. Tento článek dále představuje možnosti vaskulární medicíny v rozvojových zemích, kde nelze aplikovat endovaskulární metody na dostačující úrovni a v dostatečném rozsahu. V tuto chvíli je jasné následující. 30denní mortalita po ošetření ruptur AAA je významně nižší v tzv. high-volume nemocnicích. Z odlišných důvodů nejsou všechny ruptury aneurysmat břišní aorty vhodné k EVAR. Otevřené řešení ruptur aneurysmat břišní aorty by mělo být operováno zkušeným cévním chirurgem pro otevřené výkony. Stejné by mělo platit pro léčbu endovaskulárních komplikací, které vyžadují konverzi v otevřený chirurgický výkon. Neexistuje ideální výkon pro léčbu AAA. Každý výkon má své výhody a nevýhody, své limity a komplikace, a také indikace a kontraindikace. Další snížení mortality u ruptur AAA bude záležet na zavedení populačně založeného skríningu, na strategii prevence pooperačního poškození orgánů, a také na pokroku nové lékařské technologie. Z toho důvodu je vzdělávání nových mladých cévních chirurgů nejen v endovaskulární, ale i v otevřené aortální chirurgii nesmírně důležité. Klíčová slova: břišní aorta – výduť – ruptura

Rupture is the most serious and lethal complication of the abdominal aortic aneurysm. Despite all improvements during the past 50 years, ruptured abdominal aortic aneurysms are still associated with very high mortality. Namely, including patients who die before reaching the hospital, the mortality rate due to abdominal aortic aneurysm rupture is 90%. On the other hand, during the last twenty years, the number of abdominal aortic aneurysms significantly increased. One of the reasons is the fact that in majority of countries the general population is older nowadays. Due to this, the number of degenerative AAA is increasing. This is also the case for patients with abdominal aortic aneurysm rupture. Age must not be the reason of a treatment refusal. Optimal therapeutic option ought to be found. The following article is based on literature analysis including current guidelines but also on my Clinic’s significant experience. Furthermore, this article show cases options for vascular medicine in undeveloped countries that can not apply endovascular procedures at a sufficient level and to a sufficient extent. At this moment the following is evident. Thirty-day-mortality after repair of ruptured abdominal aortic aneurysms is significantly lower in high-volume hospitals. Due to different reasons all ruptured abdominal aortic aneurysms are not suitable for EVAR. Open repair of ruptured abdominal aortic aneurysm should be performed by experienced open vascular surgeons. This could also be said for the treatment of endovascular complications that require open surgical conversion. There is no ideal procedure for the treatment of AAA. Each has its own advantages and disadvantages, its own limits and complications, as well as indications and contraindications. Future reductions in mortality of ruptured abdominal aortic aneurysms will depend on implementation of population-based screening; on strategies to prevent postoperative organ injury and also on new medical technology improvements. Taking this into consideration, education of young vascular surgeons in endovascular but also in open aortic surgery, is of vast importance. Key words: abdominal aorta – aneurysm – rupture

• MeSH
• aneurysma břišní aorty * diagnóza   chirurgie   mortalita   patofyziologie   MeSH
• aorta abdominalis * chirurgie   patofyziologie   MeSH
• endovaskulární výkony využití   MeSH
• lidé MeSH
• perioperační péče MeSH
• pooperační péče MeSH
• předoperační péče MeSH
• rizikové faktory MeSH
• ruptura aorty * chirurgie   komplikace   mortalita   patofyziologie   MeSH
• statistika jako téma MeSH
• výkony cévní chirurgie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• přehledy MeSH

OBJECTIVES: To validate a porcine model of ruptured abdominal aortic aneurysm (rAAA) repair. DESIGN: Experimental study. METHODS: Ten experimental and five sham-operated pigs were studied. Instrumentation for cardiac output (CO) measurement, regional blood flow (renal-REN and portal-PORT) and blood sampling (inferior vena cava (IVC), renal and portal vein) was done. Microcirculation was visualised sublingually and in ileostoma. Protocol: simulation of rAAA with bleeding (mean arterial pressure (MAP) 45 mmHg) and increased abdominal pressure (25 mmHg) for 4 h; 2 h of infrarenal clamp with shed blood retransfusion; 11 h of post-surgery care. RESULTS: Six experimental pigs completed the protocol and are presented. Bleeding decreased CO to 95%, PORT to 80% and REN to 10% of baseline. From clamping on CO and PORT increased above baseline whereas REN (47%) with creatinine clearance remained compromised till the end. Microcirculation was affected more in ileum than sublingually. Approximately threefold increase in cytokines (tumour necrosis factor-α (TNF-alpha), interleukin (IL)-6 and IL-10) and oxidative stress markers (thiobarbituric acid-reactive substances (TBARs) and 4-hydroxy-2-trans-nonenal (HNE) was observed. Only mild increase in IL-6 and TBARs was observed in sham-operated animals. Organ histology did not reveal differences between groups. CONCLUSIONS: This near-lethal model of rAAA induced expected severe deterioration of haemodynamics and metabolism accompanied with a moderate inflammatory and oxidative stress response.

• MeSH
• aneurysma břišní aorty krev   etiologie   patofyziologie   chirurgie   MeSH
• biologické markery krev   MeSH
• časové faktory MeSH
• cytokiny krev   MeSH
• hemodynamika MeSH
• hypertenze etiologie   MeSH
• krvácení etiologie   MeSH
• mediátory zánětu krev   MeSH
• mikrocirkulace MeSH
• modely nemocí na zvířatech MeSH
• monitorování fyziologických funkcí MeSH
• oxidační stres MeSH
• reprodukovatelnost výsledků MeSH
• ruptura aorty krev   etiologie   patofyziologie   chirurgie   MeSH
• Sus scrofa MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• validační studie MeSH

• Klíčová slova
• aortální disekce,
• MeSH
• aneurysma břišní aorty MeSH
• aneurysma hrudní aorty MeSH
• aortální aneurysma MeSH
• balónková angioplastika * metody   MeSH
• disekce MeSH
• endovaskulární výkony metody   MeSH
• lidé MeSH
• nemoci aorty * patologie   MeSH
• ruptura aorty * etiologie   klasifikace   patofyziologie   terapie   MeSH
• Check Tag
• lidé MeSH

OBJECTIVES: The role of the intraluminal thrombus (ILT) in abdominal aortic aneurysm (AAA) rupture is controversial, and it is still not clear if an ILT increases or decreases AAA rupture risk. Specifically, signs of bleeding in the ILT are considered to increase AAA rupture risk. To further explore this hypothesis, intact AAAs (n = 4) with clear signs of fissures in the ILT, identified by computed tomography angiography (CTA) were investigated. METHODS: Two different cases of ILT fissuring were investigated, where (1) ILT fissures were extracted directly from the CTA data and (2) a hypothetical fissure was introduced in the otherwise-intact ILT tissue. Wall stress distributions were predicted based on detailed Finite Element (FE) models. RESULTS: ILT fissures extracted from CTA data locally increase the mechanical stress in the underlying wall by up to 30%. The largest impact on wall stress was observed if the ILT crack reaches the aneurysm wall, or if it involves large parts of the ILT. By contrast, a concentric failure in the medial ILT, which does not reach the aneurysm wall, has almost no impact on wall stress distribution. Hypothetical ILT fissures that connect the lumen with the wall cause a twofold increase of the stress in the underlying wall. CONCLUSIONS: ILT fissures increase the stress in the underlying wall, whereas regions other than that remain unaffected. If ILT fissures reach the wall or involve large parts of the ILT, the resulting increase in wall stress could possibly cause AAA rupture.

• MeSH
• analýza metodou konečných prvků MeSH
• aneurysma břišní aorty komplikace   patofyziologie   radiografie   MeSH
• aortografie metody   MeSH
• hodnocení rizik MeSH
• lidé MeSH
• mechanický stres MeSH
• modely kardiovaskulární MeSH
• počítačová rentgenová tomografie MeSH
• počítačová simulace MeSH
• prognóza MeSH
• ruptura aorty etiologie   patofyziologie   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• trombóza komplikace   patofyziologie   radiografie   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH