Misdiagnosis of ruptured abdominal aortic aneurysm: systematic review and meta-analysis

Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms

OBJECTIVE

The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy.

METHODS

The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence.

RESULTS

A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed.

CONCLUSION

The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.

Status of diagnosis and therapy of abdominal aortic aneurysms

Abdominal aortic aneurysms (AAAs) are characterized by localized dilation of the abdominal aorta. They are associated with several serious consequences, including compression of adjacent abdominal organs, pain, treatment-related financial expenditure. The main complication of AAA is aortic rupture, which is responsible for about 200,000 deaths per year worldwide. An increasing number of researchers are dedicating their efforts to study AAA, resulting in significant progress in this field. Despite the commendable progress made thus far, there remains a lack of established methods to effectively decelerate the dilation of aneurysms. Therefore, further studies are imperative to expand our understanding and enhance our knowledge concerning AAAs. Although numerous factors are known to be associated with the occurrence and progression of AAA, the exact pathway of development remains unclear. While asymptomatic at most times, AAA features a highly unpredictable disease course, which could culminate in the highly deadly rupture of the aneurysmal aorta. Current guidelines recommend watchful waiting and lifestyle adjustment for smaller, slow-growing aneurysms, while elective/prophylactic surgical repairs including open repair and endovascular aneurysm repair are recommended for larger aneurysms that have grown beyond certain thresholds (55 mm for males and 50 mm for females). The latter is a minimally invasive procedure and is widely believed to be suited for patients with a poor general condition. However, several concerns have recently been raised regarding the postoperative complications and possible loss of associated survival benefits on it. In this review, we aimed to highlight the current status of diagnosis and treatment of AAA by an in-depth analysis of the findings from literatures.

Abdominal Pain in the Emergency Department: How to Select the Correct Imaging for Diagnosis

Abdominal pain is a common presenting complaint in the emergency department, and utilization of diagnostic imaging is often a key tool in determining its etiology. Plain radiography has limited utility in this population. Computed tomography (CT) is the imaging modality of choice for undifferentiated abdominal pain. Ultrasound and magnetic resonance imaging may be helpful in specific scenarios, primarily in pediatrics and pregnancy, and offer the benefit of eliminating ionizing radiation risk of CT. Guidance for imaging selection is determined by location of pain, special patient considerations, and specific suspected etiologies. Expert guidance is offered by the American College of Radiology Appropriateness Criteria^® which outlines imaging options based on location of pain.

Abdominal aortic aneurysm rupture presenting with focal weakness and altered mental status: a case report

Background

Abdominal aortic aneurysms (AAA) can present asymptomatically and may be found through routine screening or seen incidentally on imaging. Rupture due to weaking of the aortic wall is the main complication of an AAA and leads to approximately 200,000 deaths annually worldwide. Clinically, AAA rupture most frequently presents with abdominal and/or back pain, pulsatile abdominal mass, and hypotension. Here, we present an unusual presentation of embolic cerebrovascular accident associated with an AAA rupture.

Case presentation

A 58-year-old African American man transported to the emergency department via ambulance presents with altered mental status and unilateral extremity weakness. The initial presentation was concerning for acute cerebrovascular accident, acute kidney injury, severe sepsis, and urinary tract infection. Several hours after the initial presentation, the patient’s abdomen began to appear distended and he became hypotensive. An abdominal CT was ordered which showed a large AAA rupture with a retroperitoneal bleed. The patient was transferred to a higher-level medical center for surgical repair.

Conclusion

Abdominal aortic aneurysm rupture can rarely present due to an acute cerebrovascular accident with altered mental status and focal neurologic deficits.

Analysis of surgical mortality in rural South Australia: a review of four major rural hospital in South Australia

Background

One‐third of Australia's population reside in rural and remote areas. This audit aims to describe all‐causes of mortality in rural general surgical patients, and identify areas of improvement.

Methods

This is a retrospective multi‐centre study involving four South Australian hospitals (Mt Gambier, Whyalla, Port Augusta, and Port Lincoln). All general surgical inpatients admitted from June 2014 to September 2019 were analysed to identify all‐cause of mortality.

Results

A total of 80 mortalities were recorded out of 26 996 admissions. The overall mortality rate of 0.3% was the same as the 2020 Victorian state‐wide Audit of Surgical Mortality. No mortality was secondary to trauma. Mean age was 79 ± 11 years and ASA was 3.9 ± 1. Malignancy was associated in over a third of cases (41.2%), mostly colorectal and pancreatic. Most cases were related to general surgical subspecialties: colorectal (51.3%), upper gastrointestinal (21.3%), hepatopancreaticobiliary (13.8%); however, there were also vascular (6.3%) and urology (3.8%) cases. The most common causes of mortality were large bowel obstruction (13.4%), ischemic bowel (10.4%), and small bowel obstruction (7.5%). Majority of mortality were beyond the surgeon's control (73.8%). Of the 21 potentially preventable mortalities, 42.9% were attributed to aspiration pneumonia and decompensated heart failure. Only one (1.3%) mortality case was due to pulmonary embolism.

Conclusion

Rural general surgical mortalities occur in older, comorbid patients. Rural surgeons should be equipped to manage basic subspeciality conditions. To further reduce mortalities, clear protocols to prevent aspiration pneumonia and resuscitation associated fluid overload are needed.

Evaluando la experiencia local: primeros 50 casos de reparo endovascular de aneurismas aórticos en Manizales, Colombia

Introducción. En las últimas décadas, la terapia endovascular en aneurismas aórticos abdominales ha ganado un papel representativo en los escenarios quirúrgicos, lo que nos motivó a conocer los resultados de este procedimiento en nuestra población. Métodos. Estudio analítico retrospectivo en el cual se incluyeron los primeros 50 casos de aneurismas aórticos abdominales con terapia endovascular, en la ciudad de Manizales, Colombia, entre los años 2015 y 2021. Se describió la población estudiada, la relación de los antecedentes prequirúrgicos con las complicaciones posoperatorias, la estancia hospitalaria y la mortalidad. Resultados. La edad promedio fue de 73 años, el sexo predominante fue el femenino (72 %), el aneurisma fusiforme fue el tipo más frecuente (63,3 %), con un diámetro promedio de 70 mm (+/- 17,3 mm). En relación con los antecedentes, el más frecuente fue hipertensión arterial (86 %), encontrándose una asociación entre la presencia de enfermedad pulmonar obstructiva crónica e hipertensión arterial con las complicaciones. Se encontró también relación entre el valor de creatinina con las complicaciones. Las complicaciones tempranas fueron de carácter leve en la mayoría de los casos (30,6 %), a diferencia de las tardías, que fueron principalmente graves (12,5 %), asociadas a una mortalidad del 10,2 % y una estancia hospitalaria promedio de 10,8 días (mediana de 5 días). Conclusiones. La población analizada tiene una alta carga de morbilidad, en la cual factores como los antecedentes médicos prequirúrgicos y la función renal, se asocian con una mayor morbilidad postquirúrgica y mortalidad.

Case Report: Experience and Lesson From Postpartum Ruptured Abdominal Aortic Aneurysm

With rapid progression and extremely high mortality brought by the ruptured aneurysm, abdominal aortic aneurysm is one of the most dangerous diseases in the field of vascular surgery. The incidence of abdominal aortic aneurysms in pregnant women is low. Because of the insidious nature of the disease, it is not easily recognized and can be easily misdiagnosed by obstetricians, which can lead to serious adverse outcomes. In this study, we aim to draw attention to this disease and raise awareness among obstetricians about this disease in pregnant women by retrospectively analyzing a rescue case of ruptured abdominal aortic aneurysm after delivery. By reporting the experience and lessons learned from this case, we aim to improve preoperative diagnosis and treatment rates, reduce missed diagnosis, and improve the prognostic outcome of patients.

AAA Revisited: A Comprehensive Review of Risk Factors, Management, and Hallmarks of Pathogenesis

Despite declining incidence and mortality rates in many countries, the abdominal aortic aneurysm (AAA) continues to represent a life-threatening cardiovascular condition with an overall prevalence of about 2-3% in the industrialized world. While the risk of AAA development is considerably higher for men of advanced age with a history of smoking, screening programs serve to detect the often asymptomatic condition and prevent aortic rupture with an associated death rate of up to 80%. This review summarizes the current knowledge on identified risk factors, the multifactorial process of pathogenesis, as well as the latest advances in medical treatment and surgical repair to provide a perspective for AAA management.

Rapid Bedside Ultrasound Evaluation of a Ruptured Abdominal Aortic Aneurysm With a Prior Repair

Ruptured aortic aneurysms carry a high risk of morbidity and mortality, particularly if not rapidly identified. We present an 87-year-old male, with a history of hypertension and prior endovascular aortic repair, who presented to the Emergency Department (ED) with several days of epigastric abdominal pain radiating to his back and flanks. The patient acutely deteriorated in the ED, and point-of-care ultrasound rapidly identified active extravasation from an abdominal aortic aneurysm with visualization of prior endograft. Point-of-care ultrasound in this patient expedited the diagnosis, resuscitation, and transfer to the operating room with definitive repair by vascular surgery. The patient recovered and was discharged in stable condition.

Abdominal Pain in the Emergency Department: Missed Diagnoses

Abdominal pain is the most common chief complaint in the Emergency Department. Abdominal pain is caused by a variety of gastrointestinal and nongastrointestinal disorders. Some frequently missed conditions include biliary pathology, appendicitis, diverticulitis, and urogenital pathology. The Emergency Medicine clinician must consider all aspects of the patient's presentation including history, physical examination, laboratory testing, and imaging. If no diagnosis is identified, close reassessment of pain, vital signs, and physical examination are necessary to ensure safe discharge. Strict verbal and written return precautions should be provided to the patient.

Review of Malpractice Lawsuits in the Diagnosis and Management of Aortic Aneurysms and Aortic Dissections

OBJECTIVE

Aortic aneurysms and dissections are prevalent causes of morbidity and mortality. The management of aortic pathologies may be called into question in malpractice suits. Malpractice claims were analyzed to understand common reasons for litigation, medical specialties involved, patient injuries, and outcomes.

METHODS

Litigation cases in the Westlaw database from September 1st, 1987 to October 23 rd, 2019 were analyzed. Search terms included "aortic aneurysm" and "aortic dissection." Data on plaintiff, defendant, litigation claims, patient injuries, misdiagnoses, and case outcomes were collected and compared for aortic aneurysms, aortic dissections, and overall cases.

RESULTS

A total of 346 cases were identified, 196 involving aortic aneurysms and 150 aortic dissections. Physician defendants were emergency medicine (29%), cardiology (20%), internal medicine (14%), radiology (11%), cardiothoracic (10%) and vascular surgery (10%). Litigation claims included "failure to diagnose and treat" (61%), "delayed diagnosis and treatment" (21%), "post-operative complications after open repair" (10%) and "negligent post-operative care" (10%). Patients with aneurysms presented with abdominal (63%) and back pain (37%), while dissections presented with chest pain (78%), abdominal pain (15%), and shortness of breath (14%). Misdiagnoses included gastrointestinal (12%), other cardiovascular (9%), and musculoskeletal conditions (9%), but many were not specified (58%). Overall, 83% of cases were wrongful death suits. Injuries included loss of consortium (23%), emotional distress (19%), and bleeding (17%). In 53% of the cases, the jury ruled in favor of the defendant. 25% of cases ruled for the plaintiff. 22% of cases resulted in a settlement. The mean rewarded for each case was $1,644,590.66 (SD: $5,939,134.58; Range: $17,500-$68,035,462).

CONCLUSION

For aortic pathologies, post-operative complications were not prominent among the reasons why suits were brought forth. This suggests improvements in education across all involved medical specialties may allow for improved diagnostic accuracy and efficient treatment, which could then translate to a decrease in associated litigation cases.

The association between fluoroquinolones and aortic dissection and aortic aneurysms: a systematic review and meta-analysis

Previous studies have drawn causal associations between fluoroquinolone use and collagen pathologies including tendon rupture and retinopathy. This meta-analysisattempted to assess the association between fluoroquinolone use and the risk of aortic dissection or aortic aneurysm. A systematic search was performed on Medline, EMBASE, and the Cochrane library. 9 studies were included in final analysis. Primary random-effects meta-analysis of 7 studies, excluding 2 pharmacovigilance studies demonstrated statistically increased odds of aortic dissection (OR, 2.38; 95% CI, 1.71-3.32) aortic aneurysm (OR, 1.98; 95% CI, 1.59-2.48), and aortic aneurysm or dissection (OR, 1.47; 95% CI, 1.13-1.89; I² = 72%) with current use of fluoroquinolones compared to their nonuser counterparts. Based on the "number needed-to-harm" analysis, 7246 (95% CI: 4329 to 14,085) patients would need to be treated with fluoroquinolones for a duration of at least three days in order for one additional patient to be harmed, assuming a population baseline incidence of aortic dissection and aneurysm rupture to be 10 per 100,000 patient-years. With strong statistical association, these findings suggest a causal relationship, warranting future research to elucidate the pathophysiological and mechanistic plausibility of this association. These findings however, should not cease prescription of fluoroquinolones, especially when clinically indicated.

Disaster Diagnoses in Geriatric Patients with Abdominal Pain

Care of geriatric patients with abdominal pain can pose significant diagnostic and therapeutic challenges to emergency physicians. Older adults rarely present with classic signs, symptoms, and laboratory abnormalities. The incidence of life-threatening emergencies, including abdominal aortic aneurysm, mesenteric ischemia, perforated viscus, and other surgical emergencies, is high. This article explores the evaluation and management of several important causes of abdominal pain in geriatric patients with an emphasis on high-risk presentations.

Feasibility of Intraoperative Fusion Imaging Using Non-Contrast CT Scan for EVAR in Ruptured Abdominal Aortic Aneurysm

Introduction

Acute renal failure is a frequent major complication (24%) of endovascular repair for ruptured abdominal aneurysm (rAAA). Iodinated contrast media is known to be nephrotoxic. This report describes a case of endovascular aneurysm repair (EVAR) under fusion imaging guidance in a patient diagnosed with a rAAA after non-contrast CT. Written consent was obtained from the patient.

Report

A 73 year old patient with stage IV chronic kidney failure and contrast-induced nephropathy was diagnosed with rAAA using non-contrast CT. Subsequently, the patient was treated with EVAR using fusion imaging.

Discussion

EVAR with fusion imaging after non-contrast CT was safe in a patient with rAAA. It could represent an option for patients with acute renal failure in emergency settings.

Point-of-care ultrasound assessment of the abdominal aorta by physician assistant students: a pilot study

OBJECTIVE

Point-of-care ultrasound (POCUS) decreases time to diagnosis and improves mortality of those diagnosed with abdominal aortic aneurysms and dissections. While medical students have demonstrated an ability to obtain adequate POCUS images of the abdominal aorta (AA), physician assistant (PA) student studies are lacking. This pilot study aims to evaluate the ability of PA students to acquire AA POCUS images.

METHODS

PA students, instructors, and models voluntarily participated. Student participants received online material to review several weeks before the study. During the study, students performed 4 precepted practice scans of the AA, and their fifth scan was recorded for review by three ultrasound fellowship trained Emergency Medicine physicians. Images were graded on proper identification and measurement of the AA, as well as interpretability of images.

RESULTS

A total of 20 PA students participated. Ninety-five percent were able to obtain interpretable transverse images of the distal aorta and longitudinal views of the aorta, and 65% were able to obtain interpretable transverse images of the proximal and mid aorta.

CONCLUSIONS

In the most rigorous evaluation of student-obtained AA POCUS images to date, we found that PA students were able to obtain adequate AA images. PA students were able to image the distal and longitudinal aorta in the transverse plane where the majority of AAAs are found to a very high degree. Results demonstrate PA students' ability to learn POCUS and encourage PA education to take steps to incorporate POCUS education and development of competency standards for PA graduates.

Misdiagnosis of ruptured abdominal aortic aneurysms is common and is associated with increased mortality

OBJECTIVE

To investigate the rate of misdiagnosis in the emergency department in patients with ruptured abdominal aortic aneurysms (rAAAs), and to investigate how misdiagnosis affects rAAA mortality.

METHODS

Data were extracted from the Swedish Cause of Death Registry and the Swedish National Registry for Vascular Surgery from 2010 to 2015. All rAAA patients registered in the health care system in the west of Sweden were identified. Medical charts for rAAA patients were reviewed, and patients who were correctly diagnosed at the first assessment in the emergency department were compared with patients who were misdiagnosed.

RESULTS

Altogether, 455 patients with rAAA were identified, including both patients who underwent surgery and those who did not. One hundred seventy-seven (38.9%) were initially misdiagnosed. The mortality rate was 74.6% in patients who were misdiagnosed, as compared with 62.9% in correctly diagnosed patients (P = .01). The adjusted odds ratio for mortality in misdiagnosed patients relative to correctly diagnosed patients was 1.83 (95% confidence interval, 1.13-2.96) (P = .01). When excluding patients offered palliative care (n = 134) after detection of the rAAA, the mortality in initially misdiagnosed patients was 65.1% as compared with 46.4% in correctly diagnosed patients (P = .001). In patients reaching surgical intervention, 37 (45.1%) of the primarily misdiagnosed patients died (30-day or in-hospital mortality) as compared with 63 (38.0%) of the correctly diagnosed (P = .34).

CONCLUSIONS

Misdiagnosis is common in patients with rAAA, and it is associated with a substantially higher risk of dying from the ruptured aneurysm.

Rate of diagnostic errors and serious misdiagnosis-related harms for major vascular events, infections, and cancers: toward a national incidence estimate using the “Big Three”

Background

Missed vascular events, infections, and cancers account for ~75% of serious harms from diagnostic errors. Just 15 diseases from these “Big Three” categories account for nearly half of all serious misdiagnosis-related harms in malpractice claims. As part of a larger project estimating total US burden of serious misdiagnosis-related harms, we performed a focused literature review to measure diagnostic error and harm rates for these 15 conditions.

Methods

We searched PubMed, Google, and cited references. For errors, we selected high-quality, modern, US-based studies, if available, and best available evidence otherwise. For harms, we used literature-based estimates of the generic (disease-agnostic) rate of serious harms (morbidity/mortality) per diagnostic error and applied claims-based severity weights to construct disease-specific rates. Results were validated via expert review and comparison to prior literature that used different methods. We used Monte Carlo analysis to construct probabilistic plausible ranges (PPRs) around estimates.

Results

Rates for the 15 diseases were drawn from 28 published studies representing 91,755 patients. Diagnostic error (false negative) rates ranged from 2.2% (myocardial infarction) to 62.1% (spinal abscess), with a median of 13.6% [interquartile range (IQR) 9.2–24.7] and an aggregate mean of 9.7% (PPR 8.2–12.3). Serious misdiagnosis-related harm rates per incident disease case ranged from 1.2% (myocardial infarction) to 35.6% (spinal abscess), with a median of 5.5% (IQR 4.6–13.6) and an aggregate mean of 5.2% (PPR 4.5–6.7). Rates were considered face valid by domain experts and consistent with prior literature reports.

Conclusions

Diagnostic improvement initiatives should focus on dangerous conditions with higher diagnostic error and misdiagnosis-related harm rates.

Frequency and causes of delayed diagnosis of visceral artery pseudoaneurysms with CT: Lessons learned

Objective

Visceral artery pseudoaneurysms (VAPA) are associated with a high morbidity and mortality, but sometimes are missed in initial computed tomography (CT) examinations. The aims of this study were to determine the frequency and causes of misdiagnoses of VAPA with CT.

Materials and Methods

We retrospectively identified 77 patients with VAPA in our database who underwent contrast-enhanced CT. The frequency of delayed diagnosis was determined and the reasons were noted. We identified the etiology of VAPA, measured size, and noted the affected vessels.

Results

Forty-five of the 77 patients (58 %) had a delayed diagnosis of VAPA. There was no difference in the rate of missed VAPA in symptomatic compared to asymptomatic patients (p = 0.255). The majority of VAPA were associated with previous surgery or interventions (n = 48/62 %). The major affected vessel was the hepatic (n = 31) followed by the splenic artery (n = 17). The main reasons for misdiagnosis were a missed arterial phase in CT (n = 16/36 %), artifacts masking the aneurysm (n = 9/20 %), overlooked pseudoaneurysm (n = 19/42 %), and misinterpretation by attending radiologists (n = 1/2 %). Missed VAPA were smaller (median 8 mm) than those VAPA that were initially diagnosed (median 13 mm, p < 0.01), but occurred with a similar frequency in larger and smaller visceral arteries (p = 0.601).

Conclusions

Our study showed that 58 % of VAPA were diagnosed with delay, with the following four reasons for misdiagnosis: Lack of an arterial contrast phase in CT, no techniques for artifact reduction, and lack of awareness of the radiologists. Avoiding delayed diagnosis will most probably improve outcome of patients with VAPA.

Strategy of endovascular versus open repair for patients with clinical diagnosis of ruptured abdominal aortic aneurysm: the IMPROVE RCT

BACKGROUND

Ruptured abdominal aortic aneurysm (AAA) is a common vascular emergency. The mortality from emergency endovascular repair may be much lower than the 40-50% reported for open surgery.

OBJECTIVE

To assess whether or not a strategy of endovascular repair compared with open repair reduces 30-day and mid-term mortality (including costs and cost-effectiveness) among patients with a suspected ruptured AAA.

DESIGN

Randomised controlled trial, with computer-generated telephone randomisation of participants in a 1 : 1 ratio, using variable block size, stratified by centre and without blinding.

SETTING

Vascular centres in the UK (n = 29) and Canada (n = 1) between 2009 and 2013.

PARTICIPANTS

A total of 613 eligible participants (480 men) with a ruptured aneurysm, clinically diagnosed at the trial centre.

INTERVENTIONS

A total of 316 participants were randomised to the endovascular strategy group (immediate computerised tomography followed by endovascular repair if anatomically suitable or, if not suitable, open repair) and 297 were randomised to the open repair group (computerised tomography optional).

MAIN OUTCOME MEASURES

The primary outcome measure was 30-day mortality, with 30-day reinterventions, costs and disposal as early secondary outcome measures. Later outcome measures included 1- and 3-year mortality, reinterventions, quality of life (QoL) and cost-effectiveness.

RESULTS

The 30-day mortality was 35.4% in the endovascular strategy group and 37.4% in the open repair group [odds ratio (OR) 0.92, 95% confidence interval (CI) 0.66 to 1.28; p = 0.62, and, after adjustment for age, sex and Hardman index, OR 0.94, 95% CI 0.67 to 1.33]. The endovascular strategy appeared to be more effective in women than in men (interaction test p = 0.02). More discharges in the endovascular strategy group (94%) than in the open repair group (77%) were directly to home (p < 0.001). Average 30-day costs were similar between groups, with the mean difference in costs being -£1186 (95% CI -£2997 to £625), favouring the endovascular strategy group. After 1 year, survival and reintervention rates were similar in the two groups, QoL (at both 3 and 12 months) was higher in the endovascular strategy group and the mean cost difference was -£2329 (95% CI -£5489 to £922). At 3 years, mortality was 48% and 56% in the endovascular strategy group and open repair group, respectively (OR 0.73, 95% CI 0.53 to 1.00; p = 0.053), with a stronger benefit for the endovascular strategy in the subgroup of 502 participants in whom repair was started for a proven rupture (OR 0.62, 95% CI 0.43 to 0.89; p = 0.009), whereas aneurysm-related reintervention rates were non-significantly higher in this group. At 3 years, considering all participants, there was a mean difference of 0.174 quality-adjusted life-years (QALYs) (95% CI 0.002 to 0.353 QALYs) and, among the endovascular strategy group, a cost difference of -£2605 (95% CI -£5966 to £702), leading to 88% of estimates in the cost-effectiveness plane being in the quadrant showing the endovascular strategy to be 'dominant'.

LIMITATIONS

Because of the pragmatic design of this trial, 33 participants in the endovascular strategy group and 26 in the open repair group breached randomisation allocation.

CONCLUSIONS

The endovascular strategy was not associated with a significant reduction in either 30-day mortality or cost but was associated with faster participant recovery. By 3 years, the endovascular strategy showed a survival and QALY gain and was highly likely to be cost-effective. Future research could include improving resuscitation for older persons with circulatory collapse, the impact of local anaesthesia and emergency consent procedures.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN48334791 and NCT00746122.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 31. See the NIHR Journals Library website for further project information.

An Abdominal Aortic Aneurysm, Intramural Thrombus and Moderate Leak in an Asian Man Presenting with Acute Gastroenteritis

Introduction

Missing a leaking abdominal aortic aneurysm (AAA) is common in medical practice because few at-risk patients have a history of AAA and many have an unusual presentation.

Background

AAA is less common among Asians than white Caucasians of the same age. Our patient had no significant risk factors apart from age and sex and had an unusual presentation.

Patient and Methods

A 67-year-old Asian man presented to the emergency room (ER) with a 1-day history of nausea, vomiting, diarrhoea, fever and abdominal pain. He was febrile, dehydrated. and had marked tenderness at the right iliac fossa. Laboratory findings suggested bacterial gastroenteritis but this did not explain the localized tenderness at the right iliac fossa.

Result and Discussion

A CT scan of the abdomen revealed an AAA arising above the origins of the renal arteries, an intramural thrombus, a retroperitoneal haematoma and a leak extending to the right iliac fossa. The patient was transferred to another hospital and underwent exploratory laparotomy, surgical repair of the aneurysm, and aortobi-iliac grafting with removal of the thrombus. The patient was discharged in good shape 3 weeks after surgery. Without the CT scan of the abdomen, the AAA could have been missed and the patient treated for severe gastroenteritis.

LEARNING POINTS

How common is imaging for low back pain in primary and emergency care? Systematic review and meta-analysis of over 4 million imaging requests across 21 years

Objectives

To (1) estimate the proportion of patients seeking care for low back pain (LBP) who are imaged and (2) explore trends in the proportion of patients who received diagnostic imaging over time. We also examined the effect of study-level factors on estimates of imaging proportion.

Data sources

Electronic searches of MEDLINE, Embase and CINAHL databases from January 1995 to December 2017.

Eligibility criteria for selecting studies

Observational designs and controlled trials that reported imaging for patients presenting to primary care or emergency care for LBP. We assessed study quality and calculated pooled proportions by care setting and imaging type, with strength of evidence assessed using the GRADE system.

Results

45 studies were included. They represented 19 451 749 consultations for LBP that had resulted in 4 343 919 imaging requests/events over 21 years. Primary care: moderate quality evidence that simple imaging proportion was 16.3% (95% CI 12.6% to 21.1%) and complex imaging was 9.2% (95% CI 6.2% to 13.5%). For any imaging, the pooled proportion was 24.8% (95% CI 19.3%to 31.1%). Emergency care: moderate quality evidence that simple imaging proportion was 26.1% (95% CI 18.2% to 35.8%) and high-quality evidence that complex imaging proportion was 8.2% (95% CI 4.4% to 15.6%). For any imaging, the pooled proportion was 35.6% (95% CI 29.8% to 41.8%). Complex imaging increased from 7.4% (95% CI 5.7% to 9.6%) for imaging requested in 1995 to 11.4% (95% CI 9.6% to 13.5%) in 2015 (relative increase of 53.5%). Between-study variability in imaging proportions was only partially explained by study-level characteristics; there were insufficient data to comment on some prespecified study-level factors.

Summary/conclusion

One in four patients who presented to primary care with LBP received imaging as did one in three who presented to the emergency department. The rate of complex imaging appears to have increased over 21 years despite guideline advice and education campaigns.

Trial registration number

CRD42016041987.

Expanding the trauma code to other causes of hemorrhagic shock — ruptured abdominal aortic aneurysms

Summary

Expediting life-saving care for hemorrhagic shock through multi-disciplinary code protocols is a potential method to improve outcomes. Trauma codes have become standard of care at most tertiary care centres; however, it is unclear if similar protocols can improve delivery of care for other forms of hemorrhagic shock. We examined the feasibility of a code protocol for ruptured abdominal aortic aneurysms (RAAAs) by reviewing the literature and comparing patient outcomes for RAAA and trauma patients at our institution, where the latter have a wellestablished trauma code protocol. We show that, despite being similarly unstable, patients with RAAA experienced delays to care milestones compared with trauma patients, even when accounting for diagnostic delays. Combining these data with present understanding of factors implicated in RAAA survival, we propose that a “CodeAAA” protocol may fill an important gap in RAAA care and that further prospective studies examining the utility of such a code are warranted.

The reassuring CT scan with a lethal diagnosis

We discuss an interesting case of a patient who presented with symptoms of abdominal and worsening chronic back pain with a known history of abdominal aortic aneurysm.

Fluoroquinolone use and risk of aortic aneurysm and dissection: nationwide cohort study

OBJECTIVE

To investigate whether oral fluoroquinolone use is associated with an increased risk of aortic aneurysm or dissection.

DESIGN

Nationwide historical cohort study using linked register data on patient characteristics, filled prescriptions, and cases of aortic aneurysm or dissection.

SETTING

Sweden, July 2006 to December 2013.

PARTICIPANTS

360 088 treatment episodes of fluoroquinolone use (78%ciprofloxacin) and propensity score matched comparator episodes of amoxicillin use (n=360 088).

MAIN OUTCOME MEASURES

Cox regression was used to estimate hazard ratios for a first diagnosis of aortic aneurysm or dissection, defined as admission to hospital or emergency department for, or death due to, aortic aneurysm or dissection, within 60 days from start of treatment.

RESULTS

Within the 60 day risk period, the rate of aortic aneurysm or dissection was 1.2 cases per 1000 person years among fluoroquinolone users and 0.7 cases per 1000 person years among amoxicillin users. Fluoroquinolone use was associated with an increased risk of aortic aneurysm or dissection (hazard ratio 1.66 (95% confidence interval 1.12 to 2.46)), with an estimated absolute difference of 82 (95% confidence interval 15 to 181) cases of aortic aneurysm or dissection by 60 days per 1 million treatment episodes. In a secondary analysis, the hazard ratio for the association with fluoroquinolone use was 1.90 (1.22 to 2.96) for aortic aneurysm and 0.93 (0.38 to 2.29) for aortic dissection.

CONCLUSIONS

In a propensity score matched cohort, fluoroquinolone use was associated with an increased risk of aortic aneurysm or dissection. This association appeared to be largely driven by aortic aneurysm.

Vascular Causes of Syncope: An Emergency Medicine Review

BACKGROUND

Syncope is a common emergency department (ED) complaint, accounting for 2% of visits annually. A wide variety of etiologies can result in syncope, and vascular causes may be deadly.

OBJECTIVE

This review evaluates vascular causes of syncope and their evaluation and management in the ED.

DISCUSSION

Syncope is defined by a brief loss of consciousness with loss of postural tone and complete, spontaneous recovery without medical intervention. Causes include cardiac, vasovagal, orthostatic, neurologic, medication-related, and idiopathic, and most cases of syncope will not receive a specific diagnosis pertaining to the cause. Emergency physicians are most concerned with life-threatening causes such as dysrhythmia and obstruction, and electrocardiogram is a primary means of evaluation. However, vascular etiologies can result in patient morbidity and mortality. These conditions include pulmonary embolism, subclavian steal, aortic dissection, cerebrovascular disease, intracerebral hemorrhage, carotid/vertebral dissection, and abdominal aortic aneurysm. A focused history and physical examination can assist emergency physicians in determining the need for further testing and management.

CONCLUSIONS

Syncope is common and may be the result of a deadly condition. The emergency physician, through history and physical examination, can determine the need for further evaluation and resuscitation of these patients, with consideration of vascular etiologies of syncope.

Ambulance smartphone tool for field triage of ruptured aortic aneurysms (FILTR): study protocol for a prospective observational validation of diagnostic accuracy

INTRODUCTION

Rupture of an abdominal aortic aneurysm (rAAA) carries a considerable mortality rate and is often fatal. rAAA can be treated through open or endovascular surgical intervention and it is possible that more rapid access to definitive intervention might be a key aspect of improving mortality for rAAA. Diagnosis is not always straightforward with up to 42% of rAAA initially misdiagnosed, introducing potentially harmful delay. There is a need for an effective clinical decision support tool for accurate prehospital diagnosis and triage to enable transfer to an appropriate centre.

METHODS AND ANALYSIS

Prospective multicentre observational study assessing the diagnostic accuracy of a prehospital smartphone triage tool for detection of rAAA. The study will be conducted across London in conjunction with London Ambulance Service (LAS). A logistic score predicting the risk of rAAA by assessing ten key parameters was developed and retrospectively validated through logistic regression analysis of ambulance records and Hospital Episode Statistics data for 2200 patients from 2005 to 2010. The triage tool is integrated into a secure mobile app for major smartphone platforms. Key parameters collected from the app will be retrospectively matched with final hospital discharge diagnosis for each patient encounter. The primary outcome is to assess the sensitivity, specificity and positive predictive value of the rAAA triage tool logistic score in prospective use as a mob app for prehospital ambulance clinicians. Data collection started in November 2014 and the study will recruit a minimum of 1150 non-consecutive patients over a time period of 2 years.

ETHICS AND DISSEMINATION

Full ethical approval has been gained for this study. The results of this study will be disseminated in peer-reviewed publications, and international/national presentations.

TRIAL REGISTRATION NUMBER

CPMS 16459; pre-results.

Outcomes before and after the Implementation of a Critical Pathway for Patients with Acute Aortic Disease

PURPOSE

Acute aortic diseases, such as aortic dissection and aortic aneurysm, can be life-threatening vascular conditions. In this study, we compared outcomes before and after the implementation of a critical pathway (CP) for patients with acute aortic disease at the emergency department (ED).

MATERIALS AND METHODS

This was a retrospective observational cohort study. The CP was composed of two phases: PRE-AORTA for early diagnosis and AORTA for prompt treatment. We compared patients who were diagnosed with acute aortic disease between pre-period (January 2010 to December 2011) and post-period (July 2012 to June 2014).

RESULTS

Ninety-four and 104 patients were diagnosed with acute aortic disease in the pre- and post-periods, respectively. After the implementation of the CP, 38.7% of acute aortic disease cases were diagnosed via PRE-AORTA. The door-to-CT time was reduced more in PRE-AORTA-activated patients [71.0 (61.0, 115.0) min vs. 113.0 (56.0, 170.5) min; p=0.026]. During the post-period, more patients received emergency intervention than during the pre-period (22.3% vs. 36.5%; p=0.029). Time until emergency intervention was reduced in patients, who visited the ED directly, from 378.0 (302.0, 489.0) min in the pre-period to 200.0 (170.0, 299.0) min in the post-period (p=0.001). The number of patients who died in the ED declined from 11 to 4 from the pre-period to the post-period. Hospital mortality decreased from 26.6% to 14.4% in the post-period (p=0.033).

CONCLUSION

After the implementation of a CP for patients with acute aortic disease, more patients received emergency intervention within a shorter time, resulting in improved hospital mortality.

Emerging strategies to treat ruptured abdominal aortic aneurysms

Population screening programmes and a falling population prevalence of smoking have led to a declining incidence of ruptured abdominal aortic aneurysms in men. However, ruptured abdominal aortic aneurysms remain a common vascular surgical emergency, with an increasing proportion of ruptures being in women. About one quarter of the ruptures have a juxta-renal aneurysm and are more challenging to repair using endovascular technologies. Endovascular technologies may not reduce the overall mortality, compared with open surgical repair, but appear to offer early benefits with respect to patient quality of life at acceptable cost. Challenges over the next 5 years include widening the access to repair, developing an accurate bedside risk scoring tool, as well as optimising strategies for pre-operative resuscitation, standardising peri-operative care and the management of post-operative complications.

Rupture rates of untreated large abdominal aortic aneurysms in patients unfit for elective repair

BACKGROUND

Elective abdominal aortic aneurysm (AAA) surgery relies on balancing the risk of the intervention against the risk of the aneurysm causing death. Although much is known about intervention at 5.5 cm, little is known about the fate of the patient unfit for elective surgery at this threshold. Medical therapy and endovascular surgery have revolutionized management of aortic aneurysms in the last 20 years and are thought to have affected rupture rates.

METHODS

MEDLINE via PubMed, EMBASE, and the Cochrane Library Database were searched for studies reporting follow-up of untreated large AAA approach from inception to January 2014. Data were pooled using random-effects analysis with standardized mean differences and 95% confidence intervals (CIs) reported. The primary end points were rupture rates and all-cause mortality per year by AAA size.

RESULTS

The search strategy identified 1892 citations, of which 11 studies comprising 1514 patients experiencing 347 ruptured AAA were included. The overall incidence of ruptured AAA in patients with AAA >5.5 cm was 5.3% (95% CI, 3.1%-7.5%) per year. This represented cumulative yearly rupture rates of 3.5% (95% CI, -1.6% to 8.7%) in AAAs 5.5 to 6.0 cm, 4.1% (95% CI, -0.7% to 9.0%) in AAAs 6.1 to 7.0 cm, and 6.3% (95% CI, -1.8% to 14.3%) in AAAs >7.0 cm. There was no heterogeneity between studies (I(2) = 0%). Only 32% of these patients were offered repair on rupturing an AAA, with a perioperative mortality of 58% (95% CI, 32%-83%). The risk of death from causes other than AAA was higher than the risk of death from rupture.

CONCLUSIONS

Rupture rates of untreated AAA were lower than those currently quoted in the literature. Non-AAA-related mortality in this group of patients is high.