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Objective: While rare variants in the COL5A1 gene have been associated with classical Ehlers-Danlos syndrome and rarely with arterial dissections, recurrent variants in COL5A1 underlying a systemic arteriopathy have not been described. Monogenic forms of multifocal fibromuscular dysplasia (mFMD) have not been previously defined. Approach and Results: We studied 4 independent probands with the COL5A1 pathogenic variant c.1540G>A, p.(Gly514Ser) who presented with arterial aneurysms, dissections, tortuosity, and mFMD affecting multiple arteries. Arterial medial fibroplasia and smooth muscle cell disorganization were confirmed histologically. The COL5A1 c.1540G>A variant is predicted to be pathogenic in silico and absent in gnomAD. The c.1540G>A variant is on a shared 160.1 kb haplotype with 0.4% frequency in Europeans. Furthermore, exome sequencing data from a cohort of 264 individuals with mFMD were examined for COL5A1 variants. In this mFMD cohort, COL5A1 c.1540G>A and 6 additional relatively rare COL5A1 variants predicted to be deleterious in silico were identified and were associated with arterial dissections ( P =0.005). Conclusions: COL5A1 c.1540G>A is the first recurring variant recognized to be associated with arterial dissections and mFMD. This variant presents with a phenotype reminiscent of vascular Ehlers-Danlos syndrome. A shared haplotype among probands supports the existence of a common founder. Relatively rare COL5A1 genetic variants predicted to be deleterious by in silico analysis were identified in ≈2.7% of mFMD cases, and as they were enriched in patients with arterial dissections, may act as disease modifiers. Molecular testing for COL5A1 should be considered in patients with a phenotype overlapping with vascular Ehlers-Danlos syndrome and mFMD.

Objectives Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) has been used clinically to limit torso bleeding and restore central perfusion. The objective of this study was to determine the sequelae of prolonged REBOA in a nonhuman primate animal model. Summary background data Prolonged duration of REBOA is associated with adverse clinical outcomes. Threshold occlusion values tied to relative risk have yet to be determined. Methods Juvenile baboons were subjected to 40% to 55% total blood volume hemorrhage to achieve profound hypotension and shock. Zone I REBOA was performed for 60 minutes to assess acute injury and survival at 4 hours (group 1; n = 7). Post-REBOA 10-day survival and complications were then compared between 60 minutes (group 2; n = 8) and 30 minutes (group 3; n = 6) REBOA animals. Results Overall survival was 20/21 (95%). IL-6 and IL-8 were elevated at 1 and 4 hours in group 1 (P = 0.005; P = 0.001). Comparing 60-minute REBOA with 30-minute REBOA, there was (1) hypertension compared with normotension (P = 0.005), (2) increased base deficit (P = 0.003), (3) elevated Troponin I (P = 0.04), and histological evidence of kidney injury (P = 0.004). In addition, group 2 demonstrated paralysis with histopathologic changes of spinal cord ischemia (SCI) in 4/8 (50%), with no SCI in group 3 (P = 0.033). Conclusions REBOA limits mortality in the primate model of severe hemorrhagic shock. However, unopposed balloon inflation in the distal thoracic aorta for 60 minutes results in high rates of spinal cord ischemia, an effect mitigated by limiting balloon inflation to 30 minutes.

BACKGROUND: The use of partial resuscitative endovascular balloon occlusion of the aorta (pREBOA) in combined hemorrhagic shock (HS) and traumatic brain injury (TBI) has not been well studied. We hypothesized that the use of pREBOA in the setting of TBI would be associated with worse clinical outcomes. METHODS: Female Yorkshire swine were randomized to the following groups: HS + TBI; HS + TBI + pREBOA; and HS + pREBOA, (n=5/cohort). Animals in the HS + TBI group were left in shock for a total of 2 hours, whereas animals assigned to pREBOA groups were treated with supraceliac pREBOA deployment (60 minutes) 1 hour into the shock period. All animals were then resuscitated, and physiologic parameters were monitored for six hours. Further fluid resuscitation and vasopressors were administered as needed. At the end of the observation period, brain hemispheric swelling (%) and lesion size (mm(3)) were assessed. RESULTS: Mortality was highest in the HS + TBI + pREBOA group (40% [2/5] vs 0% [0/5] in the other groups, p = 0.1). Severity of shock was greatest in the HS + TBI + pREBOA group, as defined by peak lactate levels and pH nadir (p < 0.05). Fluid resuscitation and norepinephrine requirements were significantly higher in the HS + TBI + pREBOA group (p < 0.05). No significant differences were noted in brain hemispheric swelling and lesion size between the groups. CONCLUSIONS: Prolonged application of pREBOA in the setting of TBI does not contribute to early worsening of brain lesion size and edema. However, the addition of TBI to HS + pREBOA may worsen the severity of shock. Providers should be aware of the potential physiologic sequelae induced by TBI. LEVEL OF EVIDENCE: not applicable (preclinical study).

Introduction: The E-cigarette form of smoking (e-cig) has rapidly increased. Potential adverse cardiovascular effects are unknown. We sought to determine if e-cig use affects Transgelin (TAGLN), an actin binding protein with multiple important cell-signaling and regulatory actions noted to be targeted by autoantibodies in AAA. Methods: Human aortas and serum from abdominal aortic aneurysm (AAA) (n=26) and non-AAA (n=15), and rat aortas from elastase-perfused (EP) or saline-perfused (SP) animals (n=3 each group) were analyzed for aortic transgelin (TAGLN) and alpha smooth muscle actin (α-sma) content, serum TAGLN content and/or serum anti-TAGLN antibodies (AB). Rats exposed to e-cig vapor (EV) 90 min/day for 4 or 8 weeks , or room air (RA) (n=6 per group), and rats undergoing aortic low-dose topical elastase (LDTE) to induce inflammation followed by EV or RA x 100 days (n=6 per group), were also analyzed. Aortas were assessed by Western blot for TAGLN and actin content, while serum studies used Elisa to detect circulating TAGLN, or anti-TAGLN antibodies. Results: Western blots revealed loss of TAGLN and α-sma in the aortas of AAA compared to control tissues. In rat AAA we observed loss of TAGLN and diminished levels of α-sma in EP compared to SP control aortas. Serum from AAA patients had increased anti-TAGLN antibodies ( P =0.085, 45% more in AAA) and circulating TAGLN (P=0.008) compared to controls. LDTE EV rat aortas had less TAGLN ( P =0.002) and α-sma ( P =0.008) compared to RA rats throughout the aorta. LDTE + EV rat serum had high levels of anti-TAGLN antibodies (P=0.027) and circulating TAGLN (P=0.007) compared to RA rats. Conclusion: These results show that AAA is associated with decreased aortic TAGLN in humans and rats in the region of the aneurysm. EV exposure alone, and especially following LDTE results in marked reduction of TAGLN throughout all segments of the aorta. Human AAA patients and EV rats with LDTE also exhibit elevation of circulating TAGLN and anti-TAGLN antibodies. These results suggest an autoimmune mechanism for TAGLN targeting in the aorta when AAA is present or e-cig vapor exposure occurs, and that e-cig use may result in cardiovascular risk.

The management of hemorrhage shock requires support of central aortic pressure including perfusion to the brain and heart as well as measures to control bleeding. Emerging endovascular techniques including resuscitative endovascular balloon occlusion of the aorta serve as potential lifesaving adjuncts in this setting. The Endovascular Skills for Trauma and Resuscitative Surgery (ESTARS) course was developed to provide fundamental endovascular training for trauma surgeons.ESTARS 2-day course incorporated pretest/posttest examinations, precourse materials, lectures, endovascular and open vascular instruments, Vascular Intervention System Trainer endovascular simulator, and live animal laboratories for training and testing. Curriculum included endovascular techniques for trauma; review of wires, sheaths, and catheters; as well as regional vascular injury management. Animal laboratories integrated arterial access, angiography, coil embolization, resuscitative endovascular balloon occlusion of the aorta, control of iliac artery injury, and vascular shunt placement. Students completed a knowledge test (precourse/postcourse) and a summative skills assessment. The test measured knowledge and judgment in vascular injury management as defined in the course objectives. Vascular Intervention System Trainer and animal laboratory were used for final examinations. Subjective performance was graded by expert observers using a global assessment scale and performance metrics.Four pilot ESTARS courses were completed, with four participants each. Knowledge and performance significantly improved after ESTARS. Mean test examination scores increased by 77% to 85%, with a mean change of 9 percentage points [paired t (15) = 7.82, p0.0001]. The test was unidimensional (Cronbach's α = 0.67). Technical skill significantly improved for both endovascular simulation and live animal laboratory examinations. All participants passed the live animal laboratory practical examination.The ESTARS curriculum is effective at teaching a basic set of endovascular skills for resuscitation and hemorrhage control to trauma surgeons. ESTARS was confirmed as a stepwise and hierarchical curriculum demonstrating measurable improvements in performance metrics and should serve as a model for future competency-based structured training in endovascular trauma skills.

BACKGROUND: Hemorrhage is a leading cause of death in military and civilian trauma. Despite the importance of the aorta as a site of hemorrhage control and resuscitative occlusion, detailed knowledge of its morphometry is lacking. The objective of this study was to characterize aortic morphometry in a trauma population, including quantification of distances as well as and diameters and definition of relevant aortic zones. METHODS: Center line measures were made (Volume Viewer) from contrast computed tomography (CT) scans of male trauma patients (18-45 years). Aortic zones were defined based on branch arteries. Zone I includes left subclavian to celiac; Zone II includes celiac to caudal renal; Zone III includes caudal renal to aortic bifurcation. Zone lengths were calculated and correlated to a novel external measure of torso extent (symphysis pubis to sternal notch). RESULTS: Eighty-eight males (mean [SD], 28 [4] years) had CT scans for the study. The median (interquartile range) lengths (mm) of Zones I, II, and III were 210 mm (202-223 mm), 33 mm (28-38 mm), and 97 mm (91-103 mm), respectively. Median aortic diameters at the left subclavian, celiac, and lowest renal arteries were 21 mm (20-23 mm), 18 mm (16-19 mm), and 15 mm (14-16 mm), respectively, and the terminal aortic diameter was 14 mm (13-15 mm). The correlation of determination for descending aortic length (all zones) against torso extend was r = 0.454. CONCLUSION: This study provides a morphometric analysis of the aorta in a male population, demonstrating consistency of length and diameter while defining distinct axial zones. Findings suggest that center line aortic distances correlate with a simple, external measure of torso extent. Morphometric study of the aorta using CT data may facilitate the development and implementation of occlusion techniques to manage noncompressible torso, pelvic, and junctional femoral hemorrhage.

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a potentially lifesaving maneuver in the setting of hemorrhagic shock. However, emergent use of REBOA is limited by existing technology, which requires large sheath arterial access and fluoroscopy-guided balloon positioning. The objectives of this study were to describe a new, fluoroscopy-free REBOA system and to compare its efficacy to existing technology. An additional objective was to characterize the survivability of 60 minutes of REBOA using these systems in a model of hemorrhagic shock.Swine (70-88 kg) in shock underwent 60 minutes of REBOA using either a self-centering, one component prototype balloon system (PBS, n = 8) inserted (8 Fr) and inflated without fluoroscopy or a two-component, commercially available balloon system (CBS, n = 8) inserted (14 Fr) with fluoroscopic guidance. Following REBOA, resuscitation occurred for 48 hours with blood, crystalloid, and vasopressors. End points included accurate balloon positioning, hemodynamics, markers of ischemia, resuscitation requirements, and mortality.Posthemorrhage mean arterial pressure (mm Hg) was similar in the CBS and PBS groups (35 [8] vs. 34 [5]; p = 0.89). Accurate balloon positioning and inflation occurred in 100% of the CBS and 88% of the PBS group. Following REBOA, mean arterial pressure increased comparably in the CBS and PBS groups (81 [20] vs. 89 [16]; p = 0.21). Lactate peaked in the CBS and PBS groups (10.8 [1.4] mmol/L vs. 13.2 [2.1] mmol/L; p = 0.01) 45 minutes following balloon deflation but returned to baseline by 24 hours. Mortality was similar between the CBS and PBS groups (12% vs. 25%, p = 0.50).This study reports the feasibility and efficacy of a novel, fluoroscopy-free REBOA system in a model of shock. Despite a significant physiologic insult, 60 minutes of REBOA is tolerated and recoverable. Development of lower profile, fluoroscopy-free endovascular balloon occlusion catheters may allow proactive aortic control in patients at risk for hemorrhagic shock and cardiovascular collapse.

BACKGROUND: Temporary vascular shunting to restore flow after vascular injury has been advocated. The effectiveness of this adjunct in protecting against ischemic injury has not been established. This study will assess the temporal impact of shunts on ischemic injury and arterial flow. METHODS: A porcine model of hind-limb ischemia via iliac artery occlusion was used (N = 36; weight [kg] ± SD: 89 ± 4.4). Animals were randomized into one control (Isc(ctrl)) and four study groups (Isc(0), Isc(1), Isc(3), and Isc(6)) according to ischemic time. Shunt placement followed ischemia, and flow and circulating injury markers were collected incrementally during 18 hours of reperfusion. Flow proportions and a calculated Ischemia Injury Index were used to characterize group differences. RESULTS: There were no intergroup differences concerning initial weight, hemodynamic, or laboratory values. Shunt patency was 92% in the absence of anticoagulation. The proportion of common femoral arterial flow to baseline flow in the Isc(6) group was lower than the Isc(ctrl) group (p = 0.02). There was a similar trend with the Isc(1) and Isc(3) groups. The Ischemia Injury Index demonstrated that there was a difference in the Isc(3) and Isc(6) groups (late shunt placement) compared with the Isc(ctrl), Isc(0), and Isc(1) groups (early shunt placement) (p < 0.001). CONCLUSION: This study provides physiologic insight into the benefit of shunts in a model of extremity ischemia. Early shunting protects the extremity from further ischemic insult and reduces circulating markers of tissue injury. Additionally, the presence of a shunt does not increase the Ischemic Injury Index and patency is maintained in the absence of heparinization.

Endovascular techniques are widespread in the management of civilian trauma and provide standard treatment for select injuries. Despite the commonality of this less invasive technology, there have been no reports on its use in wartime. The objective of this study was to describe the implementation of endovascular capability at a level III surgical facility in Iraq and illustrate the effectiveness of catheter-based techniques.From September 1, 2004 through April 30, 2007, injuries at the Air Force Theater Hospital, Balad, Iraq, were registered in a database and reviewed. Patients in whom endovascular procedures were performed comprise the study group (N = 139).During this period, 150 catheter-based procedures were performed, including placement of 39 vena cava filters. The 111 nonfilter procedures were performed in the setting of extremity (N = 72), cervical (N = 19), and torso (N = 20) injuries. Of the diagnostic procedures, an abnormal finding was present in 67 (61%) cases, and 47 of these underwent either open surgical repair (N = 30) or endovascular treatment (N = 17). Endovascular therapies fell into three categories: embolization (N = 10), covered stent placement (N = 5), or miscellaneous (N = 2). The technical success rate of endovascular treatments was 100%, and procedure-related complications were uncommon (N = 4; 3%).This report is the first to demonstrate the effectiveness of diagnostic and therapeutic endovascular capability in the management of acute wartime injury. Implementation of this capability has unique requirements related to imaging and a trauma-specific endovascular inventory. Once established, however, endovascular capability markedly expands the injury management armamentarium and, in certain cases, provides the preferred treatment.

Background— Neutrophils may be an important source of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9), two matrix-degrading enzymes thought to be critical in the formation of an abdominal aortic aneurysm (AAA). The purpose of this investigation was to test the hypothesis that neutrophil depletion would limit experimental AAA formation by altering one or both of these enzymes. Methods and Results— Control, rabbit serum–treated (RS; n=27) or anti-neutrophil-antibody–treated (anti-PMN; n=25) C57BL/6 mice underwent aortic elastase perfusion to induce experimental aneurysms. Anti-PMN–treated mice became neutropenic (mean, 349 cells/μL), experiencing an 84% decrease in the circulating absolute neutrophil count ( P P P =0.02) and macrophages (6.1 versus 2.1 cells per 5 HPFs, P =0.005) as compared with anti-PMN–treated mice. There were no differences in monocyte chemotactic protein-1 or macrophage inflammatory protein-1α chemokine levels between groups by enzyme-linked immunosorbent assay. Neutrophil collagenase (MMP-8) expression was detected only in the 14-day control mice, with increased MMP-8 protein levels by Western blotting ( P =0.017), and MMP-8–positive neutrophils were seen almost exclusively in this group. Conversely, there were no statistical differences in MMP-2 or MMP-9 mRNA expression, protein levels, enzyme activity, or immunostaining patterns between groups. When C57BL/6 wild-type (n=15) and MMP-8–deficient mice (n=17) were subjected to elastase perfusion, however, ADs at 14 days were no different in size (134±7.9% versus 154±9.9%; P =0.603), which suggests that MMP-8 serves only as a marker for the presence of neutrophils and is not critical for AAA formation. Conclusions— Circulating neutrophils are an important initial component of experimental AAA formation. Neutrophil depletion inhibits AAA development through a non–MMP-2/9–mediated mechanism associated with attenuated inflammatory cell recruitment.

Background— This investigation tested the hypothesis that L-selectin is important in experimental abdominal aortic aneurysm (AAA) formation in rodents. Methods and Results— Rat abdominal aortas were perfused with saline (control) or porcine pancreatic elastase and studied on postperfusion days 1, 2, 4, 7, and 14 (n=5 per treatment group per day). Neutrophil (polymorphonucleur leukocyte, PMN) and macrophage counts per high-powered field (HPF) were performed on fixed sections. L-selectin expression and protein levels in aortic tissue were determined by polymerase chain reaction and Western blot, respectively. Elastase-perfused aortic diameters were significantly increased compared with control aortas at all time points except day 1 ( P P =0.001). L-selectin mRNA expression in elastase-perfused aortas was 18 ( P =0.018), 17 ( P P =0.02) times greater than control aortas at days 1, 2, and 4, respectively. Western blot demonstrated a significant 69% increase in L-selectin protein at day 7 in elastase- as compared with saline-perfused aortas ( P =0.005). Subsequent experiments involved similar studies on postperfusion days 4, 7, and 14 of aortas from C57BL/6 wild-type (WT) mice (n=21) and L-selectin–knockout (LKO) mice (n=19). LKO mice had significantly smaller aortic diameters at day 14 as compared with WT mice (88% versus 123%, P =0.02). PMN counts were significantly greater in elastase-perfused WT mouse aortas as compared with LKO mouse aortas at day 4 after perfusion (12.8 versus 4.8 PMNs/HPF, P =0.02). Macrophage counts were significantly greater at all time points after perfusion in elastase-perfused WT mouse aortas compared with elastase-perfused LKO mouse aortas, with a maximum difference at day 7 after perfusion (13.3 versus 0.5 macrophages/HPF, P Conclusion— L-selectin–mediated neutrophil recruitment may be a critical early step in AAA formation.

Acute lower extremity ischemia is a common vascular disease and is a cause of considerable morbidity and mortality. In 2000, abdominal aortic and lower extremity arterial embolism and thrombosis affected 213,000 patients in the United States.1 Hospitalization costs of treating the individual patient range from $6000 to $45,000.2-4 In an evolving era of less invasive therapies, several randomized controlled clinical trials have suggested that catheter-directed thrombolysis is as effective as surgical revascularization in preventing limb-loss and mortality in these patients.4-8 Unfortunately, most such trials included patients with ischemic insults ranging from 7 to 14 days in duration. These patients may have subacute, not critical, limb ischemia, having a longer window for re-establishing blood flow and a lesser reperfusion injury. In addition, many patients in these trials had a history of chronic occlusive disease and some had prior arterial bypasses as the target for thrombolytic therapy. A distinction between subacute (SVS Class I) and true limb-threatening ischemia (SVS classes IIa, Iib, and III) becomes relevant regarding the urgency of care and risk of limb loss.9 Endovascular catheter-directed thrombolysis may be appropriate for limb-threatening ischemia, but it usually takes longer to return blood flow to the limb, is associated with increased risk of major hemorrhage, and increases costs due to repeated arteriography and longer ICU care compared with surgical therapy. The latter shortcomings must be balanced against open thrombectomy’s greater physiological stress on an already ill patient and the possibility that an urgent bypass may be needed.10-11 Obvious factors related to improved outcomes are: (1) precise patient categorization of the degree of ischemia; (2) etiology as judged by history and physical examination; and (3) an appropriate therapeutic intervention. The current study was undertaken using a database representing the United States population to define the contemporary national impact of acute lower extremity ischemia, coupled with a retrospective review of data from a single institution that carefully restricted the categorization of ischemia and identified those factors that reduce the rates of amputation and death.

Introduction: Abdominal Aortic Aneurysm (AAA) development is linked to smoking and is characterized by extracellular matrix remodeling by MMP2 and -9. We hypothesized that MMP2 and -9 secretions and regulation in response to cigarette smoke is modulated by interactions between resident cells within the aorta, namely, aortic smooth muscles, endothelial cells, and infiltrating macrophages and could influence AAA formation and/or progression. Methods: Aqueous extract of cigarette smoke (AEC) was applied to male rat aortic smooth muscle (RASMC), endothelial (RAEC) or RAW cells in serum free medium (SFM). After 24h the cells were washed, fresh SFM was added and collected after 24h. This conditioned media (CM) was applied to the cells for 24h, again washed, fresh SFM added, and then incubated for 72h, at which point the media was saved for MMP2 and -9 analysis by zymography while the cellular protein was used to determine the ratio (pS/pJ) of phospho-Stat3 (pStat3) and phospho-Jak2 (pJak2) by western blot. Results: Unstimulated CM from RAW cells increased MMP2 by 24% (p=0.0357), MMP9 by 282.1% (p=0.0004) and pS/pJ by 136.5% in RASMC. AEC-CM from RAW and RAEC cells increased MMP9 by 200.5% (p=0.0004) and 17.1% (p=0.0301) respectively in RASMC and corresponding increases in pS/pJ (305.7% and 227.6%, respectively). AEC-CM derived from RAW cells induced RAEC to produce moderate amounts of MMP2 (16.5%, p=0.0140) and MMP9 (29.5%, p=0.0207) and a 137.0% increase in pS/pJ. RAW cells receiving unstimulated CM from RASMC and RAEC cells produced significant amounts of MMP9 (127.7%, p=0.0026 and 236.8%, p=0.0020, respectively) and increased levels of pS/pJ ratios (45.2% and 1282.8%, respectively). Moreover, AEC-CM from RASMC and RAEC induced significant production of MMP9 from RAW cells (154.8%, p=0.0001 and 162.4%, p=0.0022, respectively) and increase in pS/pJ ratios (1348.2%, and 1493.9%, respectively) over baseline. Conclusion: This is the first in vitro study demonstrating that cigarette smoke results in differential interactions between aortic smooth muscle cells, endothelial cells, and macrophage lineage cells resulting in enhanced levels of MMP2, MMP9, pStat3 and pJak2. These interactions may play an important role in AAA formation under in vivo conditions.

Introduction Cigarette smoke has a strong correlation with abdominal aortic aneurysm (AAA) formation and is characterized by increased levels of MMP9 in the aorta. We hypothesized that smoke-induced MMP9 regulation is mediated by the Jak/Stat pathway thereby contributing to AAA formation. Methods Aqueous extract of cigarette smoke (AEC) was applied to male rat aortic vascular smooth muscle cells (RASMC) for 24 hours (h) in serum free medium (SFM), using SFM alone for controls. Media were collected for MMP2 and MMP9 zymography and proteins extracted from cells for phospho-Stat3 (pStat3), total Stat3 (T-Stat3), phospho-Jak2 (pJak2) and total Jak2 (T-Jak2) western blots. RASMC were transfected by siRNAs for Jak2 and Stat3 before AEC treatment to evaluate induction of MMPs. Coimmunoprecipitation and immunofluorescence microscopy investigated complex formation and cellular distribution of Jak2 and Stat3 following AEC treatment. Results MMP9 was increased in the medium of the AEC treated RASMC (P=0.005) and pro-MMP2 slightly elevated (P=0.055) at 24h compared to controls. By western blot protein extracts from AEC treated RASMC showed up regulation of pStat3, pJak2 and T-Jak2 and stable T-Stat3 compared with controls. siRNA transfection of RASMC for Jak2, Stat3 and a combination of Jak2 and Stat3 reduced MMP9 (P Conclusion This study suggests that cigarette smoke may result in AAA formation through Jak/Stat-mediated MMP9 production. siRNA inhibition of the Jak/Stat pathway greatly reduced AEC-induced MMP9 by RASMC and suggests a potential therapeutic target for the treatment of AAA.

Objectives: Ruptured abdominal aortic aneurysm (AAA) is associated with a uniformly high mortality rate, and a noninvasive method is necessary to detect vascular wall inflammation that may assist in predicting AAA rupture. The ability of 18F-FDG positron emission tomography to identify increased inflammation in the porcine pancreatic elastase (PPE) perfusion model in Sprague-Dawley rats exposed to β-aminopropionitrile (BAPN) to stimulate AAA rupture was evaluated. Methods: BAPN (300mg/kg subcutaneous) was administered daily starting 3d prior to infrarenal abdominal aortic exposure to PPE and daily until AAA harvest or rupture (BAPN, n=10). Control rats only underwent PPE exposure (n=8). Aortic diameter was evaluated at 3, 7, and 14d post PPE exposure utilizing ultrasound (US, 12MHz). Both groups were imaged with 18F-FDG microPET. AAA maximum to mean muscle 18F-FDG uptake ratios (AMR) were determined. AAA rupture sites were identified at post rupture harvest. Matrix metalloproteinase (MMP) 2 and 9 zymogramatic activities, in terms of integrated optical density (IOD), were assessed at 7d (control n=3, BAPN n=4) and 14d post PPE exposure (control n=3, rupture n=3). Results: Mean 7d aortic diameter increases of 251 ± 29.4% and 340 ± 56.0% (p=0.20) were observed in control and rupture groups, respectively. Four BAPN exposed rats ruptured within 24h after 18F-FDG microPET. Considering the entire AAA, mean AMRs for control and ruptured groups were not significantly different at 15.3 ± 1.6 and 15.5 ± 1.9, respectively. However, considering the 18F-FDG uptake at known rupture sites, the mean AMR for ruptured AAAs was significantly greater than that of control AAAs (AMR 13.2 ± 1.1 vs. 8.4 ± 1.3, p=0.02). IOD values of 8373 ± 827 and 4655 ± 1851 (p=0.14) were observed for MMP9 activity in 14d control and ruptured AAA tissue, representing an 80% increase in ruptured AAA tissue. IOD values of 4760 ± 647 and 1190 ± 87 (p=0.03) were observed for MMP2 activity in 14d control and ruptured AAA tissue, respectively, representing a 75% decrease in ruptured AAA tissue. No differences in MMP2 or 9 activities for control and BAPN exposed rats were appreciated at 7d post PPE exposure. Conclusions: Increased MMP9 activity in ruptured rat AAA tissue parallels what has been observed in ruptured human AAA tissue. Decreased MMP2 activity in ruptured AAA tissue may represent decreased smooth muscle cell presence. Increased 18F-FDG uptake by rat AAA walls, in regions of known rupture, suggests that FDG-PET may be used to predict AAA rupture.

Objectives: Ruptured abdominal aortic aneurysm (AAA) is associated with a high mortality rate, and a noninvasive test is necessary to detect vascular wall inflammation that may aid in predicting AAA rupture. The ability of 18F-FDG positron emission tomography (PET) imaging to identify increased inflammation in the porcine pancreatic elastase (PPE) perfusion model in Sprague-Dawley rats exposed to β-aminopropionitrile (BAPN) to stimulate AAA rupture was evaluated. Methods: Starting 3d prior to infrarenal abdominal aortic exposure to PPE, BAPN (300mg/kg subcutaneous) was administered daily until AAA harvest or rupture (BAPN, n=9). Control rats only underwent PPE exposure (n=8). Aortic diameter was evaluated at 3, 7, and 14d post PPE exposure utilizing ultrasound (US, 12MHz). Both groups were imaged with 18F-FDG microPET (control n=4, rupture n=3) 7d post PPE exposure. Maximum AAA to mean muscle 18F-FDG uptake ratios (AMR) were determined. Matrix metalloproteinase (MMP) 2 and 9 zymogramatic activities, in terms of integrated optical density (IOD), were assessed at 7d (control n=3, BAPN n=4) and 14d post PPE exposure (control n=3, rupture n=3). Results: Mean 7d aortic diameter increases of 247% and 398% (p=0.014) were observed in control and rupture groups, respectively, with no evidence of dissection in BAPN exposed rats on US. Three BAPN exposed rats ruptured within 24h after 18F-FDG microPET, with mean AMRs for the control and ruptured groups of 86.5 and 281.9 (p=0.048), respectively. IOD values of 4655 and 8373 (p=0.140) were determined for MMP9 activity in 14d control and ruptured AAA tissue, respectively, representing an 80% increase in ruptured AAA tissue. IOD values of 4760 and 1190 (p=0.032) were determined for MMP2 activity in 14d control and ruptured AAA tissue, respectively, representing a 75% decrease in ruptured AAA tissue. No differences in MMP2 or 9 activities for control and BAPN exposed rats were observed at 7d post PPE exposure. Conclusions: Alterations in MMP2 and 9 activities in BAPN exposed, ruptured, rat AAA tissues parallel alterations in MMP2 and 9 activities in ruptured, human AAA tissues observed by others. Increased 18F-FDG uptake by rat AAAs that subsequently ruptured suggests that FDG-PET may be used to predict AAA rupture in humans.

Objectives: The vast majority of Abdominal Aortic Aneurysm (AAA) patients have a history of smoking. The current hypothesis is that smoking induces post-translational protein modifications within the abdominal aorta resulting in site-specific antigenic targets for humoral immunity, and leads to a complex inflammatory milieu that ultimately gives rise to mature AAAs. Methods: Plasma samples from patients with AAAs were separated by smoking status (Non-smoker = NS [n = 5]; Smoker = S [n = 15]; Prior Smoker = PS [n = 36]). Aortic wall was harvested from AAA (n = 5) and healthy control aorta (n = 5). Membrane proteins were extracted from AAA aortas by phase separation and bound to affinity columns. Plasma from NS, S, and PS groups was passed through these columns to isolate immunoglobulins (eluted IgGs). Duplicate samples of pooled control aortic tissue proteins underwent electrophoresis for Western blotting and Coomassie staining. Western blots were developed with eluted IgGs from the NS, S, and PS groups as well as IgGs from healthy volunteers as negative control. The Western blots were analyzed for differences in banding patterns between NS and S or PS groups and the corresponding proteins from Coomassie stained gels were excised for Mass Spectrometry (LC-MS/MS analysis). Results: Western blot experiments revealed a ∼38 kD band in NS but no correlating band in S and PS groups, as well as ∼22 kD and ∼33 kD bands present in S and PS but no correlating bands in the NS group. LC-MS/MS analysis of these 3 bands identified the encompassed proteins as having sequence homologies with TROPOMYOSIN 1, TROPOMYOSIN 2, TRANSGELIN, INTEGRIN BETA-1, VERSICAN, PEROXIREDOXIN 2 and OSTEOGLYCIN (Mimecan), and that these proteins differed in relative abundance between the three groups. Conclusions: We identified putative proteins in normal human aortas that could represent autoimmune targets leading to AAA development. The discrepancy between the molecular weights of putative targets and the bands used for LC-MS/MS analysis possibly reflects post-translational processing of the larger parent protein resulting in auto-antigenicity.

The purpose of this investigation was to determine whether there is a relation between body mass index (BMI) classes and early postoperative outcomes in elderly patients undergoing vascular surgery. We hypothesized that being overweight or obese increases the risks of surgery.Data from the American College of Surgeons' National Surgical Quality Improvement Program Participant Use Data File was used to identify the BMI (kg/m(2)) and 30-day outcomes of 25,337 patients aged ≥ 65 years undergoing vascular surgery from 2005 to 2007. Patients were stratified into 6 BMI classes: (1) underweight (BMI ≤ 18.5 kg/m(2)), (2) normal (BMI = 18.6-24.9 kg/m(2)), (3) overweight (BMI = 25-29.9 kg/m(2)), (4) obese class I (BMI = 30-34.9 kg/m(2)), (5) obese class II (BMI = 35-39.9 kg/m(2)), and (6) obese class III (BMI ≥ 40 kg/m(2)). Morbidity and mortality rates across all BMI classes were subjected to univariate and multiple logistic regression analyses.Mortality rates varied among the BMI classes: 9.4% underweight, 4.0% normal, 3.0 overweight and obese I, 3.3% obese II, and 4.6% obese III (P0.001). Major postoperative morbidity paralleled the risk of death. Independent preoperative factors associated with mortality included diabetes mellitus, chronic obstructive pulmonary disease, active congestive heart failure, recent weight loss, disseminated cancer, and an inability to function independently. Each of these factors was statistically more important than the BMI alone in defining an increased risk of surgery.Increased BMI alone was not a major factor predicting perioperative 30-day mortality in this cohort of elderly surgical patients; the effect was a nonlinear one with a reversed J-curve response documenting the poorest outcomes in underweight, normal, and a slight increase in excessively obese patients.