Abdominal aortic aneurysm: an illustrated narrative review

Extravertebral low back pain: a scoping review

BACKGROUND

Low back pain (LBP) is one of the most common reasons for consultation in general practice. Currently, LBP is categorised into specific and non-specific causes. However, extravertebral causes, such as abdominal aortic aneurysm or pancreatitis, are not being considered.

METHODS

A systematic literature search was performed across MEDLINE, Embase, and the Cochrane library, complemented by a handsearch. Studies conducted between 1 January 2001 and 31 December 2020, where LBP was the main symptom, were included.

RESULTS

The literature search identified 6040 studies, from which duplicates were removed, leaving 4105 studies for title and abstract screening. Subsequently, 265 publications were selected for inclusion, with an additional 197 publications identified through the handsearch. The majority of the studies were case reports and case series, predominantly originating from specialised care settings. A clear distinction between vertebral or rare causes of LBP was not always possible. A range of diseases were identified as potential extravertebral causes of LBP, encompassing gynaecological, urological, vascular, systemic, and gastrointestinal diseases. Notably, guidelines exhibited inconsistencies in addressing extravertebral causes.

DISCUSSION

Prior to this review, there has been no systematic investigation into extravertebral causes of LBP. Although these causes are rare, the absence of robust and reliable epidemiological data hinders a comprehensive understanding, as well as the lack of standardised protocols, which contributes to a lack of accurate description of indicative symptoms. While there are certain disease-specific characteristics, such as non-mechanical or cyclical LBP, and atypical accompanying symptoms like fever, abdominal pain, or leg swelling, that may suggest extravertebral causes, it is important to recognise that these features are not universally present in every patient.

CONCLUSION

The differential diagnosis of extravertebral LBP is extensive with relatively low prevalence rates dependent on the clinical setting. Clinicians should maintain a high index of suspicion for extravertebral aetiologies, especially in patients presenting with atypical accompanying symptoms.

Association of abdominal aortic calcification and lower back pain in patients with degenerative spondylolisthesis

ABSTRACT

Abdominal aortic calcification (AAC) is hypothesized to lead to ischemic pain of the lower back. This retrospective study aims to identify the relationship between AAC and lower back pain (LBP) in patients with degenerative lumbar spondylolisthesis. Lower back pain was assessed preoperatively and 2 years after surgery using the numeric analogue scale. Abdominal aortic calcification was assessed according to the Kauppila classification and was grouped into no, moderate, and severe. A multivariable regression, adjusted for age, sex, body mass index, hypertension, and smoking status, was used to assess the association between AAC and preoperative/postoperative LBP as well as change in LBP after surgery. A total of 262 patients were included in the final analysis. The multivariable logistic regression demonstrated an increased odds ratio (OR) for preoperative LBP ≥ 4 numeric analogue scale (OR = 9.49, 95% confidence interval [CI]: 2.71-40.59, P < 0.001) and postoperative LBP ≥ 4 (OR = 1.72, 95% CI: 0.92-3.21, P = 0.008) in patients with severe AAC compared with patients with no AAC. Both moderate and severe AAC were associated with reduced improvement in LBP after surgery (moderate AAC: OR = 0.44, 95% CI: 0.22-0.85, P = 0.016; severe AAC: OR = 0.41, 95% CI: 0.2-0.82, P = 0.012). This study demonstrates an independent association between AAC and LBP and reduced improvement after surgery. Evaluation of AAC could play a role in patient education and might be considered part of the differential diagnosis for LBP, although further prospective studies are needed.

Exploring the Effect and Mechanism of Si-Miao-Yong-An Decoction on Abdominal Aortic Aneurysm Based on Mice Experiment and Bioinformatics Analysis

Background

Abdominal aortic aneurysm (AAA) is a fatal disease characterized by high morbidity and mortality in old population. Globally, effective drugs for AAA are still limited. Si-Miao-Yong-An decoction (SMYAD), a traditional Chinese medicine (TCM) formula with a high medical value, was reported to be successfully used in an old AAA patient. Thus, we reason that SMYAD may serve as a potential anti-AAA regime.

Objective

The exact effects and detailed mechanisms of SMYAD on AAA were explored by using the experimental study and bioinformatics analysis.

Methods

Firstly, C57BL/6N mice induced by Bap and Ang II were utilized to reproduce the AAA model, and the effects of SMYAD were systematically assessed according to histology, immunohistochemistry, and enzyme-linked immunosorbent assay (ELISA). Then, network pharmacology was applied to identify the biological processes, pathways, and hub targets of SMYAD against AAA; moreover, molecular docking was utilized to identify the binding ability and action targets.

Results

In an animal experiment, SMYAD was found to effectively alleviate the degree of pathological expansion of abdominal aorta and reduce the incidence of Bap/Ang II-induced AAA, along with reducing the damage to elastic lamella, attenuating infiltration of macrophage, and lowering the circulating IL-6 level corresponding to the animal study, and network pharmacology revealed the detailed mechanisms of SMYAD on AAA that were related to pathways of inflammatory response, defense response, apoptotic, cell migration and adhesion, and reactive oxygen species metabolic process. Then, seven targets, IL-6, TNF, HSP90AA1, RELA, PTGS2, ESR1, and MMP9, were identified as hub targets of SMYAD against AAA. Furthermore, molecular docking verification revealed that the active compounds of SMYAD had good binding ability and clear binding site with core targets related to AAA formation.

Conclusion

SMYAD can suppress AAA development through multicompound, multitarget, and multipathway, which provides a research direction for further study.

DRD4 (Dopamine D4 Receptor) Mitigate Abdominal Aortic Aneurysm via Decreasing P38 MAPK (mitogen-activated protein kinase)/NOX4 (NADPH Oxidase 4) Axis-Associated Oxidative Stress

[Figure: see text].

Histone Deacetylase SIRT1, Smooth Muscle Cell Function, and Vascular Diseases

Vascular smooth muscle cells (VSMCs), located in the media of artery, play key roles in maintaining the normal vascular physiological functions. Abnormality in VSMCs is implicated in vascular diseases (VDs), including atherosclerosis, abdominal aortic aneurysm (AAA), aortic dissection, and hypertension by regulating the process of inflammation, phenotypic switching, and extracellular matrix degradation. Sirtuins (SIRTs), a family of proteins containing seven members (from SIRT1 to SIRT7) in mammals, function as NAD⁺-dependent histone deacetylases and ADP-ribosyltransferases. In recent decades, great attention has been paid to the cardiovascular protective effects of SIRTs, especially SIRT1, suggesting a new therapeutic target for the treatment of VDs. In this review, we introduce the basic functions of SIRT1 against VSMC senescence, and summarize the contribution of SIRT1 derived from VSMCs in VDs. Finally, the potential new strategies based on SIRT1 activation have also been discussed with an emphasis on SIRT1 activators and calorie restriction to improve the prognosis of VDs.

Differential Diagnosis in a Patient Presenting With Both Systemic and Neuromusculoskeletal Pathology: Resident's Case Problem

Study Design Resident's case problem. Background Patients presenting with multiple symptomatic areas pose a diagnostic challenge for the physical therapist. Though musculoskeletal and nonmusculoskeletal symptoms typically present separately, they can occur simultaneously and mimic each other. Consequently, the ability to differentiate between musculoskeletal and nonmusculoskeletal symptoms is an important skill for physical therapists. The purpose of this resident's case problem was to describe the clinical-reasoning process leading to medical and physical therapy management of a patient presenting with upper and lower back pain, bilateral radiating arm and leg pain, and abdominal pain. Diagnosis The patient was a 30-year-old woman referred to physical therapy for upper and lower back pain. A detailed history and thorough examination revealed that the patient had signs and symptoms consistent with a possible abdominal aortic aneurysm. She was referred for medical management and was diagnosed with symptomatic cholelithiasis. She subsequently had a cholecystectomy, which ultimately resolved her abdominal pain and reduced her pain in other areas significantly. Although many of her symptoms resolved postoperatively, her pain in other areas remained and was potentially musculoskeletal in origin. Following re-evaluation and 3 physical therapy treatments over a 2-month period, she was relatively symptom free at discharge and had achieved all functional rehabilitation goals. Discussion This resident's case problem provides an opportunity to discuss the differential diagnosis, clinical reasoning, and outcome of a patient who presented with both systemic and neuromusculoskeletal pathology. Level of Evidence Differential diagnosis, level 5. J Orthop Sports Phys Ther 2018;48(6):496-503. Epub 6 Feb 2018. doi:10.2519/jospt.2018.7652.

Epidemiology and contemporary management of abdominal aortic aneurysms

Abdominal aortic aneurysm (AAA) is most commonly defined as a maximal diameter of the abdominal aorta in excess of 3 cm in either anterior-posterior or transverse planes or, alternatively, as a focal dilation ≥ 1.5 times the diameter of the normal adjacent arterial segment. Risk factors for the development of AAA include age > 60, tobacco use, male gender, Caucasian race, and family history of AAA. Aneurysm growth and rupture risk appear to be associated with persistent tobacco use, female gender, and chronic pulmonary disease. The majority of AAAs are asymptomatic and detected incidentally on various imaging studies, including abdominal ultrasound, and computed tomographic angiography. Symptoms associated with AAA may include abdominal or back pain, thromboembolization, atheroembolization, aortic rupture, or development of an arteriovenous or aortoenteric fistula. The Screening Abdominal Aortic Aneurysms Efficiently (SAAAVE) Act provides coverage for a one-time screening abdominal ultrasound at age 65 for men who have smoked at least 100 cigarettes and women who have family history of AAA disease. Medical management is recommended for asymptomatic patients with AAAs < 5 cm in diameter and focuses on modifiable risk factors, including smoking cessation and blood pressure control. Primary indications for intervention in patients with AAA include development of symptoms, rupture, rapid aneurysm growth (> 5 mm/6 months), or presence of a fusiform aneurysm with maximum diameter of 5.5 cm or greater. Intervention for AAA includes conventional open surgical repair and endovascular aortic stent graft repair.

Geometric Predictors of Abdominal Aortic Aneurysm Maximum Wall Stress

Abdominal aortic aneurysm (AAA) is a dilation of the abdominal aorta (above 50 % of its original diameter), which can cause death upon rupturing. It usually grows asymptomatically leading to late clinical intervention. The medical criteria to indicate surgery are based on measuring the diameter and growth rate, but in many cases aneurysms fail at uncharacterized critical values. In search of a more efficient technique in predicting AAA failure, there is consensus on the importance of studying its geometric characteristics and estimation of the wall stress, but no fully successful correlation has been found between the two yet. This work examines the relationship between a parameterized geometry (18 input variables and 10 dependent indices) and 1 output variable: the maximum wall stress. Design of Experiments (DOE) techniques are used to generate 183 geometric configurations, for which Finite Element Analyses are performed using ANSYS™ state-of-the-art solver with a hyperelastic, isotropic and homogeneous arterial model for the wall, considering systolic internal pressure (steady state) and the restriction of longitudinal movement at the blood vessel end-sections. Due to the large number of independent parameters to consider, a preliminary Parameters Correlation analysis was performed to determine if a correlation between all input parameters and the maximum stress existed. The correlations between input parameters and the output variable were determined using the Spearman Rank correlation. Correlations with the maximum wall stress for: maximum diameter (ρ = 0.46), wall thickness (ρ = 0.35), d_c parameter (ρ = 0.21) and tortuosity (ρ = 0.55) were found. The response surface function between geometry and maximum wall stress was estimated by three models: Universal Kriging geostatistical regression (18 parameters), multiple linear regression (4 parameters) and multiple exponential regression (4 parameters). The models accounted for the stress variance by 99 %, 61 % and 66 %, respectively, with average percentage errors of 0.12 %, 16 % and 17 %, respectively. The solution spaces obtained from this study might provide physicians with a better estimation of the AAA rupture potential and thus, facilitate safer and anticipated treatments of the condition.

Assessing the Stability of Aortic Aneurysms with Pulse Wave Imaging

Purpose To assess whether the stability of murine aortic aneurysms is associated with the homogeneity of pulse wave propagation within the saccular wall. Materials and Methods All animal procedures were approved by the institutional Animal Care and Use Committee. Apolipoprotein E and tissue inhibitor of metalloproteinases-1 knockout mice (n = 26) were infused with angiotensin II by using subcutaneously implanted osmotic pumps, with an additional control mouse used for histologic examination (n = 1). Pulse wave imaging (PWI) was performed just before infusion and 15 days after infusion by using 40-MHz ultrasonography at 8000 frames per second (with electrocardiographic gating). Aneurysm appearance on B-mode images was monitored every 2-3 days for 30 days. On the basis of B-mode images obtained after 30 days, aneurysms were deemed to have been unstable if they had ruptured; otherwise, they were deemed stable. Statistical significance was assessed by using two-tailed t tests. Results In normal aortas, the pulse waves propagated at relatively constant velocities (mean ± standard deviation, 2.8 m/sec ± 0.9). Fifteen days after infusion, all mice had developed aneurysms, with significant (P < .001/12) changes in maximum anterior-posterior diameter (increase of 54.9% ± 2.5) and pulse wave velocity (PWV) (decrease of 1.3 m/sec ± 0.8). While there was no significant difference in these parameters (P = .45 for diameter and P = .55 for PWV) between stable aneurysms (n = 12) and unstable aneurysms (n = 14), the standard deviation of the high-resolution PWV was significantly higher (P < .001/12) in unstable aneurysms (5.7 m/sec ± 1.6) than in stable ones (3.2 m/sec ± 0.9). Conclusion High-resolution PWI was used to measure the local homogeneity of pulse wave propagation within the saccular wall, which is lower in unstable aneurysms than in stable ones. Hence, if proven to add additional information beyond size and appearance in human studies, PWI could potentially be used to assess the stability of aneurysms by providing information that is complementary to the anatomic data obtained with conventional B-mode imaging. ^© RSNA, 2016 Online supplemental material is available for this article.

Monitoring and staging abdominal aortic aneurysm disease with pulse wave imaging

The abdominal aortic aneurysm (AAA) is a silent and often deadly vascular disease caused by the localized weakening of the arterial wall. Previous work has indicated that local changes in wall stiffness can be detected with pulse wave imaging (PWI), which is a non-invasive technique for tracking the propagation of pulse waves along the aorta at high spatial and temporal resolutions. The aim of this study was to assess the capability of PWI to monitor and stage AAA progression in a murine model of the disease. ApoE/TIMP-1 knockout mice (N = 18) were given angiotensin II for 30 days via subcutaneously implanted osmotic pumps. The suprarenal sections of the abdominal aortas were imaged every 2-3 d after implantation using a 30-MHz VisualSonics Vevo 770 with 15-μm lateral resolution. Pulse wave propagation was monitored at an effective frame rate of 8 kHz by using retrospective electrocardiogram gating and by performing 1-D cross-correlation on the radiofrequency signals to obtain the displacements induced by the waves. In normal aortas, the pulse waves propagated at constant velocities (2.8 ± 0.9 m/s, r(2) = 0.89 ± 0.11), indicating that the composition of these vessels was relatively homogeneous. In the mice that developed AAAs (N = 10), the wave speeds in the aneurysm sac were 45% lower (1.6 ± 0.6 m/s) and were more variable (r(2) = 0.66 ± 0.23). Moreover, the wave-induced wall displacements were at least 80% lower within the sacs compared with the surrounding vessel. Finally, in mice that developed fissures (N = 5) or ruptures (N = 3) at the sites of their AAA, higher displacements directed out of the lumen and with no discernible wave pattern (r(2) < 0.20) were observed throughout the cardiac cycle. These findings indicate that PWI can be used to distinguish normal murine aortas from aneurysmal, fissured and ruptured ones. Hence, PWI could potentially be used to monitor and stage human aneurysms by providing information complementary to standard B-mode ultrasound.

Exploration of the mechanisms by which 3,4-benzopyrene promotes angiotensin II-induced abdominal aortic aneurysm formation in mice

OBJECTIVE

This study examined the influence of 3,4-benzopyrene (BaP), a compound found in cigarette smoke, on the formation of angiotensin II (Ang II)-induced abdominal aortic aneurysm (AAA) formation in mice and the underlying mechanisms.

METHODS

C57/B6n mice were divided into four groups. The control group received a weekly intraperitoneal injection of medium-chain triglycerides. The Ang II group received a daily Ang II infusion (0.72 mg/kg) and a weekly intraperitoneal injection of medium-chain triglycerides. The Ang II/BaP group received a daily Ang II infusion (0.72 mg/kg) and a weekly intraperitoneal BaP injection (10 mg/kg, dissolved in medium-chain triglycerides). The BaP group received a weekly intraperitoneal BaP injection (10 mg/kg). After 5 weeks, abdominal aortic diameter was determined. Aortic tissues underwent hematoxylin and eosin, Masson, and immunochemistry staining for evaluation of vascular wall structure, collagen, macrophage infiltration, matrix metalloproteinases (MMPs), and apoptosis.

RESULTS

The Ang II infusion and BaP injection induced AAAs in 41.67% of mice vs 25% in the Ang II group (P < .05). The average aortic diameter increased in the Ang II/BaP group compared with the Ang II group (1.40 ± 0.25 vs 1.2 ± 0.23 mm; P < .05). Average aortic muscular cell apoptosis was higher in the Ang II/BaP group (31% ± 12%) than in the Ang II (19% ± 5%; P < .05) or BaP groups (23% ± 4%; P < .05). Aortic macrophage infiltration and expression of MMP-2, MMP-9, MMP-12, and nuclear factor-κB increased (0.56 ± 0.12, 0.47 ± 0.13, 0.49 ± 0.14, 0.49 ± 0.11, and 0.42 ± 0.12, respectively) in the Ang II/BaP group compared with the Ang II group (0.27 ± 0.08, 0.25 ± 0.06, 0.24 ± 0.09, 0.24 ± 0.09, and 0.23 ± 0.06, respectively; P < .05 for all).

CONCLUSIONS

BaP promotes Ang II-induced AAA formation in mice via elevating infiltration of macrophages, activating nuclear factor-κB, upregulating the expression of MMP-2, MMP-9, and MMP-12, and increasing the apoptosis of vascular muscle cells in its synergistic effect with Ang II in aortic wall.

Clinical detection of abdominal aortic aneurysm in a 74-year-old man in chiropractic practice

OBJECTIVE

The purpose of this article is to present a case of abdominal aortic aneurysm to illustrate its clinical detection through history and physical examination and the importance of this condition to the chiropractic clinical setting.

CLINICAL FEATURES

A 74-year-old retired man consulted a doctor of chiropractic for chronic low back pain. The history and physical examination confirmed chronic sacroiliac and a lumbar facet dysfunction. After 5 weeks, the patient stated he had stomach cramps. After this, a more thorough abdominal examination was done. The doctor of chiropractic detected an enlarged pulsatile mass upon abdominal palpation.

INTERVENTION AND OUTCOME

The patient was sent to the cardiologist and had successful surgery within weeks.

CONCLUSION

An abdominal aortic aneurysm has specific symptoms and associated risk factors. If known risk factors are present, a clinical examination needs to be carried out, even though sensitivity of the clinical examination may be low. It should be a differential diagnosis in every male patient older than 50 years with low back pain. In case of suspicion, the patient should be referred for advanced imaging.

Genomic DNA pooling strategy for next-generation sequencing-based rare variant discovery in abdominal aortic aneurysm regions of interest-challenges and limitations

The costs and efforts for sample preparation of hundreds of individuals, their genomic enrichment for regions of interest, and sufficient deep sequencing bring a significant burden to next-generation sequencing-based experiments. We investigated whether pooling of samples at the level of genomic DNA would be a more versatile strategy for lowering the costs and efforts for common disease-associated rare variant detection in candidate genes or associated loci in a substantial patient cohort. We performed a pilot experiment using five pools of 20 abdominal aortic aneurysm (AAA) patients that were enriched on separate microarrays for the reported 9p21.3 associated locus and 42 additional AAA candidate genes, and sequenced on the SOLiD platform. Here, we discuss challenges and limitations connected to this approach and show that the high number of novel variants detected per pool and allele frequency deviations to the usually highly false positive cut-off region for variant detection in non-pooled samples can be limiting factors for successful variant prioritization and confirmation. We conclude that barcode indexing of individual samples before pooling followed by a multiplexed enrichment strategy should be preferred for detection of rare genetic variants in larger sample sets rather than a genomic DNA pooling strategy.

Genome-wide association study identifies a sequence variant within the DAB2IP gene conferring susceptibility to abdominal aortic aneurysm

We performed a genome-wide association study on 1,292 individuals with abdominal aortic aneurysms (AAAs) and 30,503 controls from Iceland and The Netherlands, with a follow-up of top markers in up to 3,267 individuals with AAAs and 7,451 controls. The A allele of rs7025486 on 9q33 was found to associate with AAA, with an odds ratio (OR) of 1.21 and P = 4.6 x 10(-10). In tests for association with other vascular diseases, we found that rs7025486[A] is associated with early onset myocardial infarction (OR = 1.18, P = 3.1 x 10(-5)), peripheral arterial disease (OR = 1.14, P = 3.9 x 10(-5)) and pulmonary embolism (OR = 1.20, P = 0.00030), but not with intracranial aneurysm or ischemic stroke. No association was observed between rs7025486[A] and common risk factors for arterial and venous diseases-that is, smoking, lipid levels, obesity, type 2 diabetes and hypertension. Rs7025486 is located within DAB2IP, which encodes an inhibitor of cell growth and survival.

Aorto-left renal cyst fistula: a rare complication of abdominal aortic aneurysm rupture

Abdominal aortic aneurysm (AAA) rupture can occur in different ways, such as closed rupture into the retroperitoneum, open rupture into the peritoneal cavity, rupture into surrounding hollow structures, and chronic contained or sealed rupture. Here, we report an unusual case of spontaneous rupture of AAA into a renal cyst that presented with hematuria, abdominal pain and shock, and which was diagnosed with multidetector computed tomography. We also review the literature on unusual patterns of AAA rupture.

The effects of anisotropy on the stress analyses of patient-specific abdominal aortic aneurysms

The local dilation of the infrarenal abdominal aorta, termed an abdominal aortic aneurysm (AAA), is often times asymptomatic and may eventually result in rupture-an event associated with a significant mortality rate. The estimation of in-vivo stresses within AAAs has been proposed as a useful tool to predict the likelihood of rupture. For the current work, a previously-derived anisotropic relation for the AAA wall was implemented into patient-specific finite element simulations of AAA. There were 35 AAAs simulated in the current work which were broken up into three groups: elective repairs (n = 21), non-ruptured repairs (n = 5), and ruptured repairs (n = 9). Peak stresses and strains were compared using the anisotropic and isotropic constitutive relations. There were significant increases in peak stress when using the anisotropic relationship (p < 0.001), even in the absence of the ILT (p = 0.014). Ruptured AAAs resulted in elevated peak stresses as compared to non-ruptured AAAs when using both the isotropic and anisotropic simulations, however these comparisons did not reach significance (p(ani) = 0.55, p(iso) = 0.73). While neither the isotropic or anisotropic simulations were able to significantly discriminate ruptured vs. non-ruptured AAAs, the lower p-value when using the anisotropic model suggests including it into patient-specific AAAs may help better identify AAAs at high risk.

Frequency of chest radiography and abdominal ultrasound in the Netherlands: 1999-2003

Chest radiography and abdominal ultrasound are two widely used diagnostic imaging techniques in Western societies. However, little is known about the frequency of these examinations and its determinants. The aim of this descriptive study was to provide detailed information on the number of chest radiography and abdominal ultrasound examinations by age, gender, referring physician and ethnicity. We used data of approximately 3,000,000 sick fund insured persons of the Health Insurance Company Agis in The Netherlands from 1999 to 2003. We calculated annual numbers and corresponding 95% confidence intervals for different age, gender and ethnicity categories. The mean age of the population was 38+/-22 years and 46% were male. Chest radiographs were ordered in 130 per 1000 persons per year and abdominal ultrasound examinations in 39 per 1000 persons per year; these frequencies did not change noticeable over the five-year period. Chest radiography was performed more often in males (156 vs. 109 per 1,000 persons/year in females; p < 0.05) and abdominal ultrasound more often in females (43 vs. 34 per 1000 persons/year in males; p < 0.05). Frequencies were highest in persons aged 70-79 years. Compared to medical specialists, general practitioners more frequently referred younger patients and females, especially for abdominal ultrasound. Up to the age of 60 years the frequencies of both chest radiography and abdominal ultrasound were higher in Turks and Moroccans compared to other persons. In conclusion, this study showed marked differences in the frequencies of chest radiography and abdominal ultrasound according to age, gender and ethnicity in The Netherlands.

Abdominal differential diagnosis in a patient referred to a physical therapy clinic for low back pain

STUDY DESIGN

Resident's case problem.

BACKGROUND

Acute back pain most often presents as musculoskeletal in nature; however, less frequently it may be the result of an underlying, or coexisting, systemic pathology. When present, the signs and symptoms of systemic pathology can mimic, or be masked by, musculoskeletal back pain, which may pose a diagnostic challenge during the clinical evaluation. The purpose of this resident's case problem is to describe the clinical reasoning process leading to a medical referral for a patient who presented to physical therapy with debilitating low back pain.

DIAGNOSIS

The patient in this resident's case problem was a 67-year-old male referred to physical therapy with a 2-week history of severe low back pain and muscle spasms. The patient history and physical examination were suggestive of musculoskeletal back pain and physical therapy treatment was initiated. Abdominal pain was elicited during an introductory therapeutic exercise, which was recognized by the therapist as a potential sign of abdominal pathology. The therapist performed an additional review of systems and an abdominal screening examination, which established the necessity of an immediate medical referral. At the emergency department, ominous abdominal pathology was safely ruled out through diagnostic imaging and the patient was treated for secondary gastrointestinal effects of opioid analgesic medications.

DISCUSSION

This resident's case problem provides an opportunity to discuss the clinical reasoning process leading to the suspicion of abdominal pathology. Specifically, this case reinforces the importance of recognizing potential signs of systemic pathology, executing an appropriate physical examination, including screening of the involved anatomical region, and providing an appropriate medical referral when indicated.

Systematic review of recent evidence for the safety and efficacy of elective endovascular repair in the management of infrarenal abdominal aortic aneurysm

Background

Conventional management of abdominal aortic aneurysm (AAA) is by open repair and is associated with a mortality rate of 2–6 per cent. Endovascular aneurysm repair (EVAR) is an alternative technique first introduced in 1991. A systematic review was undertaken of the evidence for the safety and efficacy of elective EVAR in the management of asymptomatic infrarenal AAA.

Methods

Thirteen electronic bibliographical databases were searched, covering biomedical, health-related, science and social science literature. Outcomes were assessed with respect to efficacy (successful deployment, technical success, conversion rates and secondary intervention rates) and safety (30-day mortality rate, procedure morbidity rates and technical issues—endoleaks, graft thrombosis, stenosis and migration).

Results

Of 606 reports identified, 61 met the inclusion criteria (three randomized and 15 non-randomized controlled trials, and 43 uncontrolled studies). There were 29 059 participants in total; 19 804 underwent EVAR. Deployment was successful in 97·6 per cent of cases. Technical success (complete aneurysm exclusion) was 81·9 per cent at discharge and 88·8 per cent at 30 days. Secondary intervention to treat endoleak or maintain graft patency was required in 16·2 per cent of patients. Mean stay in the intensive care unit and mean hospital stay were significantly shorter following EVAR. The 30-day mortality rate for EVAR was 1·6 per cent (randomized controlled trials) and 2·0 per cent in nonrandomized trials and case series. Technical complications comprised stent migration (4·0 per cent), graft limb thrombosis (3·9 per cent), endoleak (type I, 6·8 per cent; type II, 10·3 per cent; type III, 4·2 per cent) and access artery injury (4·8 per cent).

Discussion

EVAR is technically effective and safe, with lower short-term morbidity and mortality rates than open surgery. However, there is a need for extended follow-up as the long-term success of EVAR in preventing aneurysm-related deaths is not yet known.