Aortic Diameter Measurements Research Articles

Intravascular ultrasound is a critical tool for accurate endograft sizing in the management of blunt thoracic aortic injury

Accurate measurement of true aortic luminal diameter (ALD) is critical for endograft sizing in endovascular treatment of blunt thoracic aortic injury (BTAI), but ALD is dynamic and changes with respect to patients' hemodynamic status. This study aimed to characterize how ALD at the time of diagnosis of BTAI compares with ALD at the time of endovascular repair and later at follow-up. This is an Institutional Review Board-approved, single-institution retrospective analysis of prospectively obtained data. Patients were included who presented between July 2007 and December 2012 with computed tomography angiography (CTA)-diagnosed BTAI; who underwent thoracic endovascular aortic repair (TEVAR); and who underwent preoperative CTA, intraoperative intravascular ultrasound (IVUS), and postimplantation CTA. Comparison measurements of the ALD were made among CTA and IVUS images at the level of the left subclavian artery (LSCA) and between initial CTA and postimplantation CTA at 10, 15, and 20 cm distal to the LSCA. Theoretical endograft sizes were determined and compared for each ALD at the LSCA. Twenty-two patients were included in the analysis. Mean age was 38 ± 14 years (range, 17-61 years), with 82% men and mean Injury Severity Score of 43 ± 11 (range, 24-66). Mean time from emergency department admission to initial CTA was -1.2 ± 5 hours (range, -13 to 11.5 hours; negative time implies imaging at an outside facility before admission). Mean time from initial CTA to IVUS was 1.2 ± 1.4 days (range, 2.5 hours-5.7 days) and from IVUS to postimplantation CTA 33 ± 45 days (range, 17 hours-169 days). Overall, ALD measured by IVUS was significantly larger than that by initial CTA (Δ2.5 ± 3.1 mm; P < .05). ALD was also larger at 10, 15, and 20 cm distal to the LSCA in comparing the postimplantation CTA with the initial CTA (Δ2.4, 2.0, and 2.0 mm, respectively; all P < .05). More than half the devices would be sized differently with ALD measured by IVUS at the time of TEVAR vs initial CTA. The ALD of patients with BTAI is significantly larger when it is measured by IVUS at the time of TEVAR compared with at the time of initial CTA. This difference in ALD may translate to undersizing of endografts used in TEVAR for BTAI. IVUS at the time of TEVAR provides a more accurate measurement of the actual ALD and should be used for endograft sizing for patients with BTAI.

Transabdominal ultrasonographic evaluation of fetal well-being in the late-term mare and cow.

In the equine practice, attempts have been made to examine the fetus in the second and third trimester of pregnancy but all of the available methods have limitations. Until now, transabdominal ultrasonography has been regarded as the most informative examination. This method allows us to measure fetal heart rate, fetal activity as well as the quality and quantity of the fetal fluids. A modified biophysical profile for horses was used by several researchers in the USA from the 1990s as a gold standard. However, it is not sensitive enough and, in the authors' experience, professionals can face difficulties during its application (e.g. for measuring aortic diameter and fetal breathing movements). In cows, this method was first used for this purpose by a Canadian research group in 2007. They reported that transabdominal ultrasound was promising but showed low sensitivity in this species. The present studies show that birth weight cannot be predicted from fetal aortic diameter measurement in cows as suggested by other researchers. Transabdominal ultrasound needs special equipment (2-3.5 MHz convex transducer) and basic ultrasonographic knowledge; however, we suggest that in most cases it can be performed with the dam placed in a stock and without shaving the examination area. The method provides useful information within 30-40 minutes, enabling the examiner to determine whether or not the fetus is alive and to recognise placentitis or twins. This technique also allows measuring the combined thickness of the uteroplacental unit, and the authors' ongoing study showed higher normal values in Lipizzaner mares compared to values in other breeds. In conclusion, with the help of advanced techniques, simple and low-cost methods should be developed for the evaluation of the pregnant dam and its fetus to assess fetal viability in the veterinary practice.

Comparison of Aortic Diameter and Area After Endovascular Treatment of Aortic Dissection

Different methods have been used to assess remodeling of the thoracic aorta after endovascular treatment of Stanford type B aortic dissections. Changes in morphology may be described using diameter, area, or volume. The aim of this study was to determine if aortic diameter measurements could be used to approximate aortic area in order to refine reporting standards. The study population encompassed 100 patients enrolled in the VIRTUE registry (designed to assess thoracic endografting with the Valiant Stent Graft System [Medtronic, Minneapolis, MN] for the treatment of type B aortic dissections). Diameter and area measurements of the true lumen, false lumen, and whole aorta were made using three-dimensional computed tomographic (3D CT) workstations, at different anatomic locations. Measurements included preoperative, postoperative, and follow-up scans. The Pearson test was used to determine general correlation between diameter and volume at each location. Scatter plots were drawn and linear regression models were used to draw a line of best fit. Comparison of these with nonlinear models was performed. Aortic true and false lumen diameter and area showed good correlation (p < 0.001) in the majority of anatomic locations. This relationship was present preoperatively and during follow-up (p < 0.001). The linear regression models fit well with high R(2) values. At very large aortic sizes nonlinear models were a slightly better fit, but this was not significant. Aortic diameter measurements correlate with luminal areas in patients with type B aortic dissection. This implies area increases proportionately with diameter over time. Therefore, diameter measurements using multiplanar reconstructions based on a central luminal line appear to be adequate when assessing aortic remodeling after endovascular treatment of aortic dissection.

Abdominal Aortic Diameter Is Increased in Males with a Family History of Abdominal Aortic Aneurysms: Results from the Danish VIVA-trial

To investigate, at a population level, whether a family history of abdominal aortic aneurysm (AAA) is independently related to increased aortic diameter and prevalence of AAA in men, and to elucidate whether the mean aortic diameter and the prevalence of AAA are different between participants with male and female relatives with AAA. Observational population-based cross-sectional study. 18,614 male participants screened for AAA in the VIVA-trial 2008-2011 with information on both family history of AAA and maximal aortic diameter. Standardized ultrasound scan measurement of maximum antero-posterior aortic diameter. Family history obtained by questionnaire. Multivariate regression analysis was used to test for confounders: age, sex, smoking, comorbidity and medication. From the screened cohort, 569 participants had at least one first degree relative diagnosed with AAA, and 38 had AAA. Participants with a family history of AAA (+FH) had a significantly larger mean maximum aortic diameter (20.50 mm) compared with participants without family history of AAA (-FH) (19.07 mm, p < .0001), and +FH with female relatives with AAA had significantly larger mean maximum aortic diameter (21.8 mm) than +FH with male relatives (19.9 mm, p = .007). Furthermore the prevalence of AAA was significantly higher among +FH (6.7%) compared with -FH (3.0%) with an odds ratio (OR) of 2.2 (95% CI: 1.6 to 3.2, p < .001) and +FH with female relatives with AAA had a more than two and a half times increased prevalence of AAA compared with +FH with male relatives with AAA with an OR of 2.65. First-degree male relatives of AAA patients have wider aortas and a twofold higher prevalence of AAA compared with the age adjusted background population. The prevalence of AAA was markedly higher in participants related to female, rather than male, patients with AAA.

Inhibiting the Th17/IL-17A-related inflammatory responses with digoxin confers protection against experimental abdominal aortic aneurysm.

T helper 17 cells and interleukin-17A have been implicated in the progression of abdominal aortic aneurysm (AAA). Retinoic acid-related orphan receptor gamma thymus, the master transcription factor of T helper 17 cell differentiation, is selectively antagonized by digoxin. However, the effect of antagonizing retinoic acid-related orphan receptor gamma thymus on AAA has not been investigated. We used human aortic sample analysis and 2 different experimental AAA models: (a) Angiotensin II (Ang II)-induced ApoE(-/-) male mice (Ang II/APOE model) and (b) porcine pancreatic elastase perfusion C57BL/6 mice (porcine pancreatic elastase/C57 model). In the Ang II/APOE model, all mice (n=80) were divided into 4 groups: sham group (saline+0.5% dimethyl sulfoxide treatment), control group (Ang II+0.5% dimethyl sulfoxide treatment), low-dose group (Ang II+low-dose digoxin, 20 μg/d per mouse), and high-dose group (Ang II+high-dose digoxin, 40 μg/d per mouse). All treatments began on day 0 after surgery. Efficacy was determined via aortic diameter and systolic blood pressure measurements, histopathology and protein expression, and flow cytometry analysis when euthenized. Human aortic tissue analysis showed that both interleukin-17A and retinoic acid-related orphan receptor gamma thymus increased in AAA tissues. The low-dose and high-dose groups had AAA incidences of 60% and 35%, respectively, compared with 70% in the control group. The T helper 17- and interleukin-17A-related inflammatory responses were dose-dependently attenuated by digoxin treatment. Digoxin was also highly effective in the porcine pancreatic elastase/C57 model. Digoxin attenuates experimental AAA progression in a model-independent manner. Antagonizing retinoic acid-related orphan receptor gamma thymus activity by digoxin may become a novel strategy for nonsurgical AAA treatment.

Automatic measurement of aortic annulus diameter in 3-dimensional Transoesophageal echocardiography

BackgroundTranscatheter aortic valve implantation involves percutaneously implanting a biomechanical aortic valve to treat severe aortic stenosis. In order to select a proper device, precise sizing of the aortic valve annulus must be completed.MethodsIn this paper, we describe a fully automatic segmentation method to measure the aortic annulus diameter in patients with aortic calcification, operating on 3-dimensional transesophageal echocardiographic images. The method is based on state estimation of a subdivision surface representation of the left ventricular outflow tract and aortic root. The state estimation is solved by an extended Kalman filter driven by edge detections normal to the subdivision surface.ResultsThe method was validated on echocardiographic recordings of 16 patients. Comparison against two manual measurements showed agreements (mean ±SD) of -0.3±1.6 and -0.2±2.3 mm for perimeter-derived diameters, compared to an interobserver agreement of -0.1±2.1 mm.ConclusionsWith this study, we demonstrated the feasibility of an efficient and fully automatic measurement of the aortic annulus in patients with aortic disease. The algorithm robustly measured the aortic annulus diameter, providing measurements indistinguishable from those done by cardiologists.

Disaster-Related Exposures and Health Effects Among U.S. Coast Guard Responders to Hurricanes Katrina and Rita: A Cross-Sectional Study

The objective of this study was to assess long-term durability of bridging stents in branched and combined branched and fenestrated endovascular aneurysm repair (B/F-EVAR) for thoracoabdominal aortic aneurysm (TAAA) and pararenal abdominal aortic aneurysm.A retrospective database analysis was performed of patients treated by B/F-EVAR for TAAA. Computed tomography angiography images were analyzed to assess patency, bridging stent angulation and migration, aneurysm diameter, and migration of the endograft.Twenty-eight patients with a median age of 70 years (interquartile range [IQR], 67-77 years) were included. Assisted technical success was 89%. Within 30 days postoperatively, five patients died. In the remaining 23 patients, median follow-up was 5.3 years (IQR, 2.9-7.2 years), and 1-, 3-, and 5-year estimated overall survival was 69%, 65%, and 44%, respectively. During follow-up, 12 of 47 (26%) branches occluded and 5 of 47 (11%) branches developed a 70% to 99% stenosis. The 1-, 3-, and 5-year estimated freedom from adverse events was 78%, 76%, and 59% for branch stents and 100%, 96%, and 90% for fenestration stents, respectively. The median distal bridging stent migration was 0.5 mm (IQR, −1.9 to 1.4; P > .05 mm). In 10 branches, migration >10 mm was seen, ranging from 14.1 mm sliding in to 23.0 mm sliding out. The angulation between branch and stent became 4 degrees more angulated (IQR, −14 to +2 degrees). In 23 branches, the angulation changed 10 degrees or more, leading to an occlusion in 7 branches, a 70% to 99% stenosis in 3 branches, and a 50% to 70% stenosis in 4 branches. In three cases, the endograft migrated >5 mm caudally, with a breach in a fenestration stent in one and a breach in a branch stent in another.The anatomic configuration of branches in B/F-EVAR of TAAAs and pararenal abdominal aortic aneurysms changes over time. The change in angle of branches and the bridging stent influences the likelihood of stenosis and occlusion. Follow-up of B/F-EVAR should include computed tomography angiography measurements of aortic diameter, endograft migration, target vessel stent length, and angulation to detect disconnection, stenosis, and occlusion.

Risk markers of cardiac events in patients with Marfan syndrome diagnosed during childhood

Risk markers of cardiovascular events in children with Marfan syndrome remain little known. We assessed the prognostic value of aortic root Z-score in patients with Marfan syndrome diagnosed during childhood. From the French multicenter database, 457 patients with Marfan syndrome, diagnosed before 18 y.o., were prospectively included in this cohort study. Echocardiographic measurements of aortic root diameters were performed at each visit. We calculated the Z-score of aortic root measurements using the Bichat formula. Mean Z-score was defined as the mean of the Z-score (mean ZS15) calculated for each measurement before the age of 16. Median age at end of FU was 15.9 years (interquartile 10.9–20.3). FU was complete for 69.5% of patients. Median FU was 4.6 years. A cardiovascular event occurred in 17 patients (3.7%, prophylactic aortic surgery n = 14, aortic dissection n = 1 and deaths n = 2). Survival free of cardiac events was 85.1% in patients with a mean ZS15 of the Valsalva diameter < 3 and 56.4% in patients with a mean ZS15 of the Valsalva diameter ≥ 3 ( P < 0.0001 by log-rank test) ( Fig. 1 ). In univariate analysis, Valsalva mean ZS15 ≥ 3, age at inclusion in the database, a lower heart rate and an increased arm/height ratio were associated with an increasing risk of cardiac events ( P < 0.0001, P = 0.04, P = 0.01 and P = 0.04 respectively). After multivariate adjustment using a cox proportional hazards model, only Valsalva mean ZS15 ≥ 3 and lack of FBN1 or TGBB mutation identified were associated with an increasing risk of cardiac events, P < 0.0001 and P = 0.04 respectively) ( Fig. 1 ). Valsalva mean ZS15 may help to identify high-risk children.

Standards of the Polish Ultrasound Society - update. Ultrasound examination of the aorta and arteries of the lower extremities.

A Doppler ultrasound examination has an advantage over other vessel imaging methods as it can be carried out by the patient's bedside and allows to make a diagnosis without exposing the patient to the inconveniency of transportation or an X-ray scan. The purpose of testing the lower extremities and the aorta is to objectively confirm a preliminary clinical diagnosis, localize lesions responsible for the symptoms of the disease, determine their severity and nature (e.g., if they are calcifications or soft lesions), and finally evaluate the hemodynamic criteria. In assessment of the aorta attention is paid not only to aortic diameter measurements, but also to the vascular lumen (dissections with the formation of two flow channels, detachments, balloting of atherosclerotic plaques, etc.) and the presence of atherosclerotic plaques with influx into them (PAU – penetrating ulcer in the plaque or lesions surrounding the aorta, such as retroperitoneal fibrosis or mycotic aneurysm). A correct diagnosis of an abdominal aortic aneurysm requires repeated measurements of the abdominal aorta diameter, and in particular its transverse dimension. When assessing the degree of peripheral arterial stenosis on the basis of hemodynamic parameters, degree of morphological stenosis must be taken into consideration. Collateral circulation may reduce the flow through the main vessel, and thus, the achieved systolic velocities are lower and may understate the degree of the assessed stenosis. Calf vessels are difficult to detect, which results both from the thickness of the muscle and the presence of calcifications. This article has been prepared on the basis of Standards of the Polish Ultrasound Society (2011) and updated on the basis of the latest reports from relevant literature.

Can non-contrast-enhanced CT (NECT) triage patients suspected of having non-traumatic acute aortic syndromes (AAS)?

This work was conducted to determine whether non-contrast-enhanced CT (NECT) of patients with suspected acute aortic syndrome (AAS) can identify patients with a very low likelihood of a positive diagnosis. In the derivation phase, patients who received both NECT and contrast-enhanced CT angiography (CTA) for suspected AAS were identified. Two readers blinded to CTA results analyzed NECTs from AAS positive and negative cases, recording maximal aortic diameters and qualitative findings of aortic disease. Logistic regression analysis was performed to identify independent positive predictors for AAS; those predictors were then used to create a decision rule. For the validation phase, NECTs from patients evaluated for AAS at a second institution were reviewed by two independent readers who recorded the presence of decision rule predictors while blinded to CTA results. In the derivation phase, 34 CTA positive and 83 CTA negative cases were reviewed. Measurements of aortic diameter alone achieved mean sensitivity and specificity of 82 % and of 83 %, respectively. Logistic regression identified aortic diameter, displaced calcifications, high attenuation aortic wall and abnormal aortic contour as independent predictors of AAS. The decision rule incorporating these findings achieved higher mean sensitivity (93 %), negative predictive value (96 %), and moderate reader agreement (kappa = 0.59). For the validation phase, application of the decision rule to 35 AAS positive and 45 AAS negative cases at the second institution yielded sensitivity of 100 % and specificity of 74 % for both readers. NECT can identify patients with a very low likelihood of AAS and potentially mitigate the urgency of performing CTA.

Abstract 305: Myeloid Cell-Specific VEGF-A Deletion Inhibits Experimental Abdominal Aortic Aneurysms

Mural macrophage infiltration and angiogenesis are histopathological hallmarks of abdominal aortic aneurysms (AAA). Macrophages produce angiogenic cytokine VEGF-A in many pathologic settings. It is not known whether VEGF-A produced by macrophages plays a role in aneurysm disease. In this study, we generated myeloid cell-specific VEGF-A conditional knockout (CKO) mice using the Cre/LoxP technology, and evaluated the influences of myeloid VEGF-A ablation on the formation and progression of aneurysm disease. AAAs were created in 10-12 week old male CKO and wild type (WT) mice via intra-aortic porcine pancreatic elastase (PPE) infusion and assessed by serial ultrasound measurements of aortic diameters followed by histology at sacrifice. Following PPE infusion, aneurysmal degeneration was significantly blunted in CKO mice. Histologically, medial elastin fragmentation, macrophage density, and mural angiogenesis were significantly diminished in the aortae of CKO mice compared to those in WT mice. Additionally, myeloid VEGF-A deletion caused marked reduction in peritoneal CD115-positive or F4/80-positive macrophages following thioglycollate injection. In conclusion, targeted deletion of VEGF-A in myeloid cells suppresses aneurysm initiation and progression in association with reduced mural macrophage accumulation and angiogenesis.

Dietary phytoestrogens inhibit experimental aneurysm formation in male mice

BackgroundThe purpose of these experiments was to test the hypothesis that dietary phytoestrogens would diminish experimental aortic aneurysm formation. Materials and methodsSix-wk-old C57BL/6 mice were divided into groups, fed either a diet with minimal phytoestrogen content or a regular commercial rodent diet with high phytoestrogen content for 2 wk. At the age of 8 wk, aortic aneurysms were induced by infusing the isolated infrarenal abdominal aorta with 0.4% elastase for 5 min. Mice were recovered and the diameter of the infused aorta was measured at postoperative days 3, 7, and 14. Abdominal aorta samples were collected for histology, cytokine array, and gelatin zymography after aortic diameter measurement. Blood samples were also collected to determine serum phytoestrogens and estradiol levels. Multiple-group comparisons were done using an analysis of variance with post hoc Tukey tests. ResultsCompared with mice on a minimal phytoestrogen diet, mice on a regular rodent diet had higher levels of serum phytoestrogens (male, 1138 ± 846 ng/dL; female, 310 ± 295 ng/dL). These serum phytoestrogen levels were also much higher than their own endogenous estradiol levels (109-fold higher for males and 35.5-fold higher for females). Although aortic diameters of female mice were unaffected by the phytoestrogen concentration in the diets, male mice on the regular rodent diet (M+ group) developed smaller aortic aneurysms than male mice on the minimal phytoestrogen diet (M− group) on postoperative day 14 (M+ 54.8 ± 8.8% versus M− 109.3 ± 37.6%; P < 0.001). During aneurysm development (postoperative days 3 and 7), there were fewer neutrophils, macrophages, and lymphocytes in the aorta from the M+ group than from the M− group. Concentrations of multiple proinflammatory cytokines (matrix metalloproteinases [MMPs]; interleukin 1β [IL-1β]; IL-6; IL-17; IL-23; monocyte chemoattractant protein-1; regulated on activation, normal T cell expressed and secreted; interferon γ; and tumor necrosis factor α) from aortas of the M+ group were also lower than those from the aortas of the M− group. Zymography also demonstrated that the M+ group had lower levels of aortic MMP-9s than the M− group on postoperative day 14 (P < 0.001 for pro-MMP-9, P < 0.001 for active MMP-9). ConclusionsThese results suggest that dietary phytoestrogens inhibit experimental aortic aneurysm formation in male mice via a reduction of the inflammatory response in the aorta wall. The protective effect of dietary phytoestrogens on aneurysm formation warrants further investigation.

Reliability of the measurement of the abdominal aortic diameter by novice operators using a pocket-sized ultrasound system

Despite favorable results of randomized studies and several guidelines, screening for abdominal aortic aneurysm is poorly implemented in most countries. In order to implement an effective abdominal aortic aneurysm screening programme, training of physicians other than cardiovascular imaging specialists is necessary. Also, the use of pocket-sized ultrasound systems seems an appealing alternative to conventional echography machines for large-scale screening. To test the hypothesis that, after a short period of specific training with a pocket-sized ultrasound system, novice operators could reliably measure the abdominal aortic diameter. We assessed the agreement between abdominal aortic diameter measurements from novice operators using a pocket-sized ultrasound system and experts using conventional machines. After focused training of novice operators, the abdominal aortic diameter was independently measured at least four times: by two experts using conventional ultrasound, by one expert using a pocket-sized ultrasound system and by at least one novice operator using the pocket-sized system; each operator was blinded to the others. The aortic diameters of 56 patients were measured. The intraclass correlation coefficients between the four sets of measurement were all>0.91 and the mean difference between the measurements was negligible (<1mm). The interoperator variability for experts using conventional machines versus novices using pocket-sized machines was ≤ 4mm in 92.0% of cases. No learning curve over time was noted. In order to screen for abdominal aortic aneurysm, the abdominal aortic diameter can be accurately measured by non-specialist physicians with pocket-sized ultrasound devices after a short period of training.

CT scan measurement of aortic annulus diameter before TAVI: Which is the most reliable method?

CT scan measurement of aortic annulus diameter before TAVI: Which is the most reliable method?

Importance of Pressure Pulse Amplification in the Association of Resting Heart Rate and Arterial Stiffness

The study by Whelton et al1 shows that resting heart rate is independently associated with arterial stiffness. Arterial stiffness was quantified as distensibility and determined from ultrasound measurements of carotid diameter and MRI measurements of aortic diameter. Distensibility, computed from the relative change in carotid diameter and relative change in aortic area for a cardiac cycle divided by the brachial pulse pressure, was related to heart rate that spanned an average range of 50.9 to 78.1 bpm between the first and the last quintile, respectively (Table 1 …

Comparison of two- and three-dimensional transthoracic echocardiography for measurement of aortic annulus diameter in children

Accurate evaluation of aortic root geometry is necessary in congenital aortic valve lesions in children, to guide surgical or angiographical intervention. To compare aortic annulus diameters measured by two- and three-dimensional transthoracic echocardiography (2D- and 3D-TTE), to determine the feasibility and reproducibility of 3D imaging and assess the dynamic changes during the cardiac cycle. Thirty children without heart disease were prospectively included. Two orthogonal aortic annulus diameters were measured offline using multiplanar reconstruction in diastole and in systole and were compared with the measurement of the aortic annulus diameter by 2D-TTE. Mean age was 11±3.6 years. Feasibility of 3D imaging was 100%. The coefficients of intra- and interobserver variability were 3.5% and 6%, respectively. The 2D mean diameter was significantly smaller than the 3D maximum diameter in systole (1.94 vs. 2.01mm; p=0.005). 2D and 3D measurements were well correlated (p<0.0001). The maximum and minimum diameters in 3D were significantly different both in systole and in diastole (p<0.001) underlining an aortic annulus eccentricity. The mean aortic annulus diameters were not significantly different between systole and diastole, with important individual variability during the cardiac cycle. This study demonstrated the feasibility and reproducibility of 3D-TTE for the assessment of the aortic annulus diameter in a normal paediatric population. Because of an underestimation of the maximum diameter by 2D-TTE and the asymmetry of the aortic annulus, 3D measurements could be important before percutaneous aortic valvuloplasty or surgical replacement.

Comparison of the AMI 9700 Aorta Scanner to Computed Tomography Imaging for Abdominal Aortic Diameter Measurement

An abdominal aortic aneurysm (AAA) is a localized dilation of the aorta to greater than 1.5 times its normal diameter. AAA is diagnosed if the diameter of the aorta is greater than 3cm, which is determined through imaging of the vessel. Elective repair before aneurysm rupture can significantly decrease mortality; thus, early detection is critical for AAA management. Despite increased point-of-care ultrasound (US) training in the medical community, the use of 2D ultrasonography is not yet ubiquitous. The AMI 9700 provides an automated way to screen for AAA at the bedside which allows for faster assessment in the emergency department (ED) compared to computed tomography (CT). This device may allow physicians to quickly detect AAA in acutely symptomatic patients, leading to decreased time to intervention and reduced mortality. Additionally, users may not need formal training in US to use the device. The primary objective of this study is to compare measurements of the abdominal aorta obtained using the AMI 9700 device with those obtained through CT imaging. A secondary objective of this study is to assess the ease of use of the AMI 9700 by comparing measurements obtained by US-trained and untrained physicians. US-trained physicians are defined as those who have completed or are currently enrolled in an US fellowship. This prospective study was conducted in the ED of North Shore University Hospital, a suburban, university-affiliated institution. A convenience sample was obtained, based on investigator availability, of patients 18 years and older undergoing an abdominal CT scan with intravenous contrast for abdominal or flank pain. Subjects received AMI 9700 scans by two user groups, US-trained and untrained physicians. The diameter of the abdominal aorta was measured at four distinct locations of the abdomen. The groups were blinded to each other's measurements, and the maximum diameter was used for comparison. The abdominal CT studies were viewed on a standard GE PACS image monitor, and the maximum diameter of the abdominal aorta was recorded. Sensitivity and specificity were calculated, along with associated 95% exact binomial confidence intervals (CI). A total of 33 subjects received both AMI 9700 and abdominal CT scans. The number of abdominal aorta diameters greater than or equal to 3cm as measured by the AMI 9700 were 9 (27.3%) and 5 (15.2%) for the US-trained and untrained groups, respectively. The number of abdominal aorta diameters less than 3cm were 24 (72.7%) and 28 (84.8%) for the US-trained and untrained groups, respectively. For the abdominal CT studies, 2 (6.1%) aorta measurements were greater than or equal to 3cm, and 31 (93.9%) were less than 3cm. Sensitivity was 100% (95% CI: 22.4-100%) and 50% (95% CI: 1.3-98.7%) for the US-trained and untrained groups, respectively. Specificity was 75.9% (95% CI: 56.5-89.7%) and 84.6% (95% CI: 65.1-95.6%) for the US-trained and untrained groups, respectively. In the hands of a clinician with US training, the AMI 9700 was highly sensitive and may be an effective screening tool for AAA in symptomatic ED patients. While specificity was high, positive results should be followed by a formal US or CT to confirm and better characterize the abdominal aorta. Enrollment will continue to improve the CI and further evaluate the role of this device as a screening tool for untrained operators.

Sources of error in the measurement of aortic diameter in computed tomography scans

This study was conducted to determine the differences in the diameter of the thoracic aorta when measured from electrocardiographic (ECG)-gated and nongated computed tomography (CT) angiography. Another aim was to define the difference in the aortic diameter when it is measured at peak systole and end diastole in ECG-gated scans. The gated and nongated CT angiograms of 27 patients (mean age, 58 ± 16 standard deviation [SD] years) obtained on a 256-slice multidetector CT scanner were used. The transverse and anteroposterior diameters and the lumen areas were measured at 1, 4, and 8 cm below the origin of the left subclavian artery. There was a significant difference in the aortic measurements of diameter between gated and nongated scans found in samples taken at 1, 4, and 8 cm distal to the left subclavian artery (P < .0001). We found a considerable difference between the systolic and diastolic diameters (P < .0001). The maximum change in diameter between systole and diastole was 2.9 ± 0.9 (SD) mm (14.5%, P < .0001) at 1 cm, 5.4 mm (22.6%; median, 1.7 mm; P < .0001) at 4 cm, and 4.4 mm (16.9%; median, 1.3 mm; P < .0001) at 8 cm. There was a significant difference between the transverse and anteroposterior diameters in systole and diastole at all locations (P < .0001): The maximum change in diameter between transverse and anteroposterior diameters in systole was 5.4 ± 1.1 (SD) mm (15.7%, P < .0001) at 1 cm, 5.8 mm (19%; median, 1.4 mm; P < .0001) at 4 cm, and 5 mm (15%; median, 1.02 mm; P < .0001) at 8 cm. There was also a substantial difference between measuring the transverse diameter directly and deriving it from the lumen area (P < .0001). Our results showed an important difference between systolic and diastolic diameters measurements in ECG-gated scans. The standard protocol for measuring aortic diameters in gated scans of the thoracic aorta uses images at end diastole because the lack of wall motion at this time provides better resolution. This is likely to result in undersizing that, in some instances, may threaten stability and the proper seal of the stent graft. The dimensions of the aorta in a gated CT should be measured at peak systole rather than the conventional end diastole used today. Most medical centers use nongated CT or gated CT scans in end diastole to calculate sizes of endografts. In view of our findings, the latter method could result in potential complications.

Abstract 515: Anti-Inflammatory Cytokine Interleukin-19 Suppresses the Formation and Progression of Experimental Abdominal Aortic Aneurysms

Inflammation plays an important role in the progression of abdominal aortic aneurysms (AAAs). Interleukin (IL)-19 is an anti-inflammatory cytokine that have been show to inhibit inflammatory process. However, its pathogenic role in AAAs is unknown. This study evaluated the effect of IL-19 treatment on the formation and progression of AAAs using transient intra-aortic infusion of porcine pancreatic elastase (PPE) in male C57BL/6 mice. Treatment efficacy was analyzed via serial in vivo transabdominal ultrasound measurements of aortic diameters and histology at sacrifice. PPE infusion significantly increased aortic IL-19 message and protein expression as well as aortic diameter through day 14 in mice. In contrast, exogenous IL-19 therapy initiated one day prior to PPE infusion significantly suppressed subsequent aortic enlargement. Additionally, IL-19 treatment initiated four days following PPE infusion limited further progression of existing aneurysms. Exogenous IL-19 treatment, initiated either pre- or post-PPE infusion, was associated with retained medial smooth muscle cellularity and elastin fibers and attenuated mural inflammation (including reduced T &amp; B cell and macrophage infiltration) in developing aneurysms. In conclusion, IL-19 limits the formation and progression of experimental AAAs.

Comparison of Aortic Annulus Diameter Measurement between Multi-Detector Computed Tomography and Echocardiography: A Meta-Analysis

Background and PurposeAccurate measurement of aortic annulus diameter is crucial for choosing suitable prosthetic size for transcatheter aortic valve implantation (TAVI). Several imaging methods are available for the measurement, but significant variability between different modalities has been observed. The purpose of this study was to systematically compare the measurements of aortic annulus diameter between multi-detector computed tomography (MDCT), transthoracic echocardiography (TTE), and transesophegeal echocardiography (TEE).MethodsPubMed and EMBASE databases between January 2000 and January 2012 were searched. We extracted data from eligible studies evaluating the aortic annulus diameter by MDCT and echocardiography (TTE, TEE, or both). We performed a random-effects meta-analysis to calculate the weighted mean differences of aortic annulus diameter measurement between MDCT, TTE, and TEE.ResultsA total of 10 eligible studies involving 581 subjects with aortic valve stenosis were included. Aortic annulus diameter measured on coronal view by MDCT (25.3±0.52 mm) was respectively larger than that measured on sagittal view by MDCT (22.7±0.37 mm), TTE (22.6±0.28 mm), and TEE (23.1±0.32 mm). The weighted mean difference of aortic annulus diameter between coronal view by MDCT and TTE these two methods was 2.97 mm, followed by the weighted mean difference of 2.53 mm between coronal view and sagittal view by MDCT, and the mean difference of 1.74 mm between coronal view on MDCT and TEE (P<0.0001 for all). The weighted mean difference of aortic annulus diameter measurement between TEE and TTE was significant but somewhat small (0.45 mm, P = 0.007).ConclusionAortic annulus diameter measured on coronal view by MDCT was robustly and significantly larger than that obtained on sagittal view by MDCT, TTE, or TEE. Such variability of aortic annulus diameter measurement by different imaging modalities cannot be ignored when developing optimal strategies for selection of prosthetic valve size in TAVI.