Diagnosis of acute thoracic aortic dissection in the emergency department

Fever of unknown origin as a primary presentation of chronic aortic dissection

Fever of unknown origin is rare as a primary presentation of aortic dissection. We describe a 69-year-old female presenting with a sustained fever. A diagnosis of chronic type A aortic dissection was established by computed tomography. Replacements of the ascending aorta and part of the aortic arch were performed. Ten days after the operation, the patient had recurrent pyrexia. A large effusion in the left pleural cavity was found. After puncture aspiration and antibiotic treatment, she recovered. She was doing well at the 5(1/2)-year follow-up.

The triple work-up for emergency department patients with acute chest pain: how often does it occur?

OBJECTIVES

To measure the degree of overlap and diagnostic yield for evaluations of acute coronary syndrome (ACS), pulmonary embolism (PE), and aortic dissection (AD) among Emergency Department (ED) patients.

METHODS

We conducted a cross-sectional descriptive study of consecutive adult patients seen in the ED of a 78,000-annual-visit urban academic medical center. Patients who had received at least one of eight of the tests used in our ED to diagnose these three diseases were identified through three methods, and a final study population list was created. Overlap of evaluations and diagnostic yields were calculated by simple descriptive statistics.

RESULTS

Over a 2-week period, 626 patient encounters among 622 unique patients were identified. Among these 626 visits, 139 (22%) included diagnostic tests for more than one of the three diagnoses of interest. The majority of these multiple tests were for ACS plus PE (n = 121, 87% of all multiple tests), whereas a minority of patients received tests for ACS plus AD (n = 14, 10% of all multiple tests) or for the "triple work-up" of ACS plus PE plus AD (n = 4, 2.9% of all multiple tests).

CONCLUSION

Although the "triple work-up" evaluation for ACS, PE, and AD is relatively uncommon, a significant number of ED patients who are evaluated for at least one of these three major chest pain syndromes receive simultaneous testing for one of the others.

The diagnosis of aortic dissection by emergency medicine ultrasound

A series of five cases of aortic dissection are presented that were diagnosed by emergency physicians using ultrasound to search the abdominal and thoracic aorta for pathology. Aortic dissection is a vascular emergency with a high morbidity and mortality, yet its presentation can be varied and subtle. This article reports the use of Emergency ultrasound in a series of five aortic dissections discovered with a limited, yet timely viewing of the aorta and heart by emergency physicians.

Overestimation of clinical diagnostic performance caused by low necropsy rates

BACKGROUND

Diagnostic sensitivity is calculated as the number of correct diagnoses divided by the sum of correct diagnoses plus the number of missed or false negative diagnoses. Because missed diagnoses are generally detected during clinical follow up or at necropsy, the low necropsy rates seen in current practice may result in overestimates of diagnostic performance. Using three target conditions (aortic dissection, pulmonary embolism, and active tuberculosis), the prevalence of clinically missed cases among necropsied and non-necropsied deaths was estimated and the impact of low necropsy rates on the apparent sensitivity of antemortem diagnosis determined.

METHODS

After reviewing case series for each target condition, the most recent study that included cases first detected at necropsy was selected and the reported sensitivity of clinical diagnosis adjusted by estimating the total number of cases that would have been detected had all decedents undergone necropsy. These estimates were based on available data for necropsy rates, time period, country (US v non-US), and case mix.

RESULTS

For all three target diagnoses, adjusting for the estimated prevalence of clinically missed cases among non-necropsied deaths produced sensitivity values outside the 95% confidence interval for the originally reported values, and well below sensitivities reported for the diagnostic tests that are usually used to detect these conditions. For active tuberculosis the sensitivity of antemortem diagnosis decreased from an apparent value of 96% to a corrected value of 83%, with a plausible range of 42-91%; for aortic dissection the sensitivity decreased from 86% to 74%; and for pulmonary embolism the reduction fell only modestly from 97% to 91% but was still lower than generally reported values of 98% or more.

CONCLUSIONS

Failure to adjust for the prevalence of missed cases among non-necropsied deaths may substantially overstate the performance of diagnostic tests and antemortem diagnosis in general, especially for conditions with high early case fatality.

ECG Manifestations of Selected Extracardiac Diseases

This article reviews the ECG manifestations of selected extracardiac diseases, including pulmonary embolism, pneumothorax, pulmonary hypertension, aortic dissection, central nervous system dis-ease, gastrointestinal disease, and sarcoidosis.

[Acute aortic dissection. Differential diagnosis of a thoracic emergency]

Acute aortic dissection is an infrequent but important differential diagnosis of acute chest pain. The variability of presenting symptoms makes it difficult to diagnose correctly. Important clinical indicators - besides chest pain - are symptoms related to acute aortic insufficiency and/or pericardial tamponade, variable acute neurologic alterations, or signs of peripheral or visceral malperfusion. The spontaneous prognosis depends on the location and extent of the dissection, and left untreated dissection carries a high mortality. The key goal of preclinical treatment is stabilization with analgesia, mild sedation (opioids, benzodiazepines) and treatment of hypertension (beta-blockers) or hypotension (fluid administration). If the patient presents with a high probability of dissection, early transfer to a specialized center appears advisable. Initial clinical diagnostic studies include transthoracic echocardiogram and computed tomography. If the ascending aorta is involved (Stanford type A) immediate replacement of the proximal aorta is necessary. Isolated dissections of the descending aorta (type B) require aggressive blood pressure control, but can be managed conservatively in most cases. A high level of vigilance is necessary in all patients to detect and treat visceral ischemia.

Acute Aortic Dissection Presenting with Primarily Abdominal Pain: A Rare Manifestation of a Deadly Disease

The objective of this study was to determine the morbidity and mortality of patients with acute thoracic aortic dissections who present primarily with abdominal pain. Nine hundred ninety-two patients (mean age, 62.1 years +/- 14.1; 68% male) encountered from 1996 to 2001 with acute thoracic aortic dissections from the International Registry of acute Aortic Dissection were studied. Patient demographics, presenting symptoms, signs of aortic dissection, aortic pathology, and mortality were compared in patients presenting primarily with abdominal pain (group I, 46 patients, 4.6%) versus all others (group II). Demographics were similar between the two groups. When signs of aortic dissection were examined, 63% of patients in group I presented with hypertension compared to only 47% of patients in group II (p = 0.04). Patients in group I were less likely to present with evidence of end-organ malperfusion. Importantly, mortality in patients with a type B dissection, specifically following surgery for the dissection, was significantly increased in patients who presented primarily with abdominal pain (group I, 28% mortality vs. group II, 10.2% mortality; p = 0.02). This study documented increased mortality in patients with acute thoracic aortic dissections who present primarily with abdominal pain, underscoring the importance of maintaining a high index of suspicion for an aortic dissection in patients who have appropriate risk factors.

Inadequate hemodynamic management in patients undergoing interfacility transfer for suspected aortic dissection

The study goal was the analysis of effectiveness of hemodynamic management of patients undergoing interfacility transport for suspected acute aortic dissection (SAAD). Our retrospective, consecutive-case review examined 62 nonhypotensive patients transported by an air emergency medical services (EMS) service during 1998 to 2002, with referral hospital diagnosis of SAAD. Of patients with systolic blood pressure (SBP) less than 120 upon air EMS arrival, antihypertensives had been given in only 23/42 (54.8%). In 19 cases where pretransport SBP is less than 120, with no referral hospital antihypertensive therapy given, median pretransport SBP was 158 (range, 122-212). In 20/62 cases (32.3%), the air EMS agency instituted antihypertensive therapy, which was successful; of 42 cases with pretransport SBP less than 120, mean intratransport SBP decrement was 24 (95% confidence interval, 16-32). In patients undergoing transport for SAAD, pretransport hemodynamic therapy was frequently omitted and often inadequate, generating an opportunity for air EMS intervention. Education to improve SAAD care should focus upon both referral hospitals and transport services.

Clinical, diagnostic, and management perspectives of aortic dissection

The incidence of aortic dissection ranges from 5 to 30 cases per million people per year, depending on the prevalence of risk factors in the study population. Although the disease is uncommon, its outcome is frequently fatal, and many patients with aortic dissection die before presentation to the hospital or prior to diagnosis. While pain is the most common symptom of aortic dissection, more than one-third of patients may develop a myriad of symptoms secondary to the involvement of the organ systems. Physical findings may be absent or, if present, could be suggestive of a diverse range of other conditions. Keeping a high clinical index of suspicion is mandatory for the accurate and rapid diagnosis of aortic dissection. CT scanning, MRI, and transesophageal echocardiography are all fairly accurate modalities that are used to diagnose aortic dissection, but each is fraught with certain limitations. The choice of the diagnostic modality depends, to a great extent, on the availability and expertise at the given institution. The management of aortic dissection has consisted of aggressive antihypertensive treatment, when associated with systemic hypertension, and surgery. Recently, endovascular stent placement has been used for the treatment of aortic dissection in select patient populations, but the experience is limited. The technique could be an option for patients who are poor surgical candidates, or in whom the risk of complications is gravely high, especially so in the patients with distal dissections. The clinical, diagnostic, and management perspectives on aortic dissection and its variants, aortic intramural hematoma and atherosclerotic aortic ulcer, are reviewed.