Brief Report

Clinical characteristics of aortic aneurysm and dissection as a cause of sudden death in outpatients

Lauren C. Pierce BA, D. Mark Courtney MD?

Department of Emergency Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA

Received 22 November 2007; revised 6 December 2007; accepted 8 December 2007

Abstract

Objective: To describe characteristics of nonhospitalized patients experiencing sudden death from aortic causes and compare with characteristics of patients experiencing nontraumatic, unexpected, outpatient death from other causes.

Methods: Retrospective case-control analysis of patients aged 18 to 65 years with nontraumatic, unexpected, outpatient cardiac arrest, emergency department (ED) resuscitation attempts, and autopsy- determined cause of death. Demographics, prodromal symptoms, and arrest characteristics were examined, and univariate comparisons between patients with aortic and those with nonaortic causes of death were performed.

Results: A total of 384 patients met inclusion criteria. Aortic pathology represented 4.4% of patients (12 dissections, 5 aneurysms). Preexisting aortic disease (n = 2) and antemortem suspicion of an aortic cause (n = 3) were uncommon. Patients with an aortic cause of death often had prodromal symptoms (53% 95% CI; 28%-77%) and hemopericardium (47% 95% CI; 23%-72%), were older, and were more likely to have a pulse in the ED, an arrest rhythm of pulseless electrical activity, and an arrest witnessed arrest by a medical provider.

Conclusion: In this sample of outpatients with cardiac arrest from aortic disease, death was not instantaneous, and hemopericardium was common in many patients with dissection.

(C) 2008

Introduction

Aortic dissection and aneurysm are commonly discussed and feared in the differential diagnosis of a wide variety of emergency department (ED) chief complaints. Aortic pathology is known to potentially cause fatality and disability [1-5]. Critically ill patients may present to the ED or emergency medical services (EMSs) without a

Supported by grant 5K23HL077404-04 from National Health Lung and Blood Institute (Dr. Courtney).

* Corresponding author. Tel.: +1 312 694 7000; fax: +1 312 926 6274.

E-mail address: [email protected] (D.M. Courtney).

known history of aortic disease or may simply present in undifferentiated shock or cardiac arrest [1,6]. Despite the fact that physicians and EMS providers are commonly taught to consider aortic dissection and aneurysm as potential life threats, little is known about clinical characteristics of sudden death from aortic pathology in the ED or prehospital setting, and the diagnosis is often missed [7].

Symptoms from aortic disease include back pain, chest pain, and abdominal pain, all of which can closely resemble symptoms of other emergent problems, such as pulmonary embolism, myocardial infarction, and Mesenteric ischemia [6]. At times, patients may be too unstable to allow for a

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complete history, examination, and diagnostic testing. However, rapid simultaneous resuscitation and evaluation must occur even in the context of shock or near arrest. A description of clinical characteristics of sudden death from aortic disease may be a helpful first step toward efforts to more rapidly and efficiently identify these patients in the ED or EMS environment.

Whereas most of the current literature describes patients who survive the ED and progress to the operating room or intensive care unit [2,3,5], the present study focuses on subjects who experience sudden death in the ED or prehospital setting. The aim of the current study is to describe clinical characteristics of outpatients who experi- ence sudden death from clear autopsy-proven aortic dissec- tion or aneurysm and compare these characteristics with those in subjects experiencing sudden death from other nonTraumatic causes.

Methods

Study design

All data were abstracted from records at the Mecklenberg County, North Carolina, Medical Examiner‘s (ME’s) Office. This retrospective case control study was approved and considered exempt from informed consent by the North- western University Institutional Review Board.

Study setting and population

Mecklenberg County contains the city of Charlotte, North Carolina, and is an urban center in the southeastern United States. The ME’s Office reviews all cases of outpatient sudden death (ED or out-of-hospital) without clear cause using past medical records, EMS records, ED records, autopsy results, and family interviews. The ME records can, therefore, function as an important source of information about outpatients who experience unexpected sudden death that is not caused by a known terminal illness.

Study protocol

The database was created by a hand review of all ME- reviewed deaths from 1992 to 1999 to identify cases of outpatient sudden death from Medical causes. Included subjects met the following criteria: aged 18 to 65 years, autopsy performed, nontraumatic death, outpatient, and transported to an ED. Patients were excluded if review indicated death is obviously caused by suicide, burns, fire, gastrointestinal hemorrhage, external hemorrhage, or toxins. Data were abstracted into a preformed data collection instrument and included EMS records, ED physician and nursing records, and ME interviews with family, witnesses, and physicians regarding antemortem events and prior medical conditions.

All subjects had a complete autopsy performed with gross dissection of all solid organs, including the brain and heart, and examination of all body cavities. Specific notation was made by the pathologist if cardiac tamponade, hemothorax, or any extension of dissection into the Carotid arteries was present.

The database was separated into cases (those with aortic aneurysm or dissection on autopsy) and controls (those with sudden death because of other causes).

Key outcome measures

The database was reviewed, and the characteristics of each aortic case were noted including demographics, type of aortic process, anatomic location, cardiac involvement, presence of pulse upon first contact with medical provider, presence of pulse upon ED arrival, primary arrest rhythm, return of spontaneous circulation, chest pain, abdominal pain, Neurological deficits (including seizure, syncope, focal neurological deficits, and altered mental status), known history of aneurysm, known history of dissection, and if present, any disease-specific primary antemortem assessments noted by the treating physician. Chest pain, abdominal pain, and neurological deficits were included in the database if reported by family, witnesses, or medical personnel.

The records of both the cases and controls were reviewed and compared. The factors compared included mean age, gender, chest pain, abdominal pain, neurological symptoms, record of pulse upon ED arrival, first arrest rhythm, whether it was witnessed, and whether it was witnessed by a medical provider.

Data analysis

Means and SDs are given for continuous data. Univariate comparisons between subjects with aortic causes of death and subjects with nonaortic causes of death were performed.

Table 1 General characteristics of the sample of ED outpatient sudden death

Total % 95% CI (N = 384)

Demographics Mean age (y) 45.9 (SD +- 10) 44.9-46.9 y Men 281 73.2 68.4%-77.5% White 214 62.2 56.8%-67.4% African American 124 36.0 31.0%-41.4% Other race ? 6 1.7 0.6%-3.8% Cause of death Acute coronary syndrome 229 59.6 54.5%-64.6% Pulmonary embolism 37 9.6 6.9%-13.0% Arrhythmia 28 7.3 4.9%-10.4% Aortic pathology 17 4.4 2.6%-7.0%

* Race data unavailable or unclear for 40 subjects.

Table 2 Clinical characteristics of patients experiencing aortic sudden death

Description	Cause of death	Pulse at ED arrival	Arrest rhythm	ROSC in ED	Chest pain	Abdominal pain	Neuro signs	ED MD assessment before autopsy
49 yo man; arrested in the ED after	Aortic dissection	Yes	VF	2	No	No	Yes	Aortic
altered mental status, seizure,	hemopericardium,			Times				dissection
R neck pain, L hemiparesis,	R common carotid
ST depression on ECG	dissection
19 yo man; history of renal failure,	Aortic dissection,	Yes	VF	No	Yes	No	No	Aortic
renal transplant; arrived at ED with	hemopericardium,							dissection
chest pain; subsequent ED arrest	autopsy evidence of
	previous PDA
	ligation
57 yo man; chest pain, dyspnea,	Aortic dissection,	Yes	PEA	Yes	Yes	No	No	None
diaphoresis; then arrest witnessed	hemopericardium
by bystander; ROSC by EMS with
pulse at arrival to ED; subsequent
arrest in ED
62 yo woman; abdominal pain, altered	Aortic dissection,	Yes	PEA	No	No	Yes	Yes	None
mental status, syncope, ECG with ST	hemopericardium
depression, then ST elevation before
arrest in the ED
48 yo woman; headache and seizure;	Aortic dissection,	No	VF	No	No	No	Yes	Cardiac arrest
brought to ED by family; VF at ED	hemopericardium
arrival
50 yo woman; witnessed by bystander;	Aortic dissection,	No	VF	No	No	No	No	Cardiac arrest
no pulse on EMS arrival	hemopericardium,
	carotid dissection,
	mediastinal
	hemorrhage
39 yo man; not witnessed	Aortic dissection,	No	PEA	No	Yes	No	No	None
	mediastinal
	hemorrhage
51 yo man; witnessed by bystander,	Aortic dissection,	No	VF	No	Yes	No	No	None
clutched chest and arrested	hemopericardium
60 yo male; not witnessed	Aortic dissection,	No	VF	No	No	No	No	None
	hemopericardium
65 yo woman; history of abdominal	Aortic dissection,	No	PEA	No	No	No	No	PE
aortic aneurysm repair; bystander	hemothorax
witnessed arrest
58 yo man; witnessed by bystander	Aortic dissection,	No	PEA	No	No	No	No	None
	extension to carotid
	and subclavian
41 yo woman; history of ascending	Aortic dissection	No	PEA	No	No	No	No	None
aortic dissection repair with graft	(descending),
9 mo prior, dyspnea, then arrest	rupture into R
witnessed by EMS	pleural space with
	hemothorax
32 yo man; exercising; arrest	Aortic aneurysm	No	AS	No	No	No	No	PE vs AMI
witnessed by bystander	rupture (ascending)
	with
	hemopericardium
60 yo man; abdominal pain; arrest	Abdominal aortic	No	PEA	No	No	Yes	No	None
witnessed by EMS	aneurysm rupture
63 yo male; found in car pulled over	Abdominal aortic	No	AS	No	No	No	No	None
in cardiac arrest	aneurysm rupture
56 yo man; abdominal pain;	Abdominal aortic	No	AS	Yes	No	Yes	No	Ruptured
arrest witnessed by bystander	aneurysm rupture							AAA

Table 2 (continued)

Description

Cause of death Pulse at ED Arrest ROSC Chest Abdominal Neuro ED MD arrival rhythm in ED pain pain signs assessment

before autopsy

58 yo man; arrest witnessed by bystander

Thoracic aortic No aneurysm rupture, hemopericardium

AS

No No No

No None

AAA indicates Abdominal aortic aneurysm; AMI, acute myocardial infarction; AS, asystole; ECG, electrocardiogram; L, left; MD, medical doctor; PDA, patent ductus arteriosus; PE, pulmonary embolism; R, right; ROSC, return of spontaneous circulation; VF, ventricular fibrillation; yo, year-old.

Proportions and differences between groups are described with 95% confidence intervals (CIs).

Results

During the study period, 384 subjects met the inclusion criteria and were brought to an ED for resuscitation attempts. They ultimately died in the ED and had a complete autopsy to determine the cause of death. The mean age was 45.9 (+-10) years and 73.2% were men. The most common cause of death was coronary artery-related etiology, comprising 59.6% of all deaths. The next most common single cause was pulmonary embolism, comprising 9.6% of deaths (Table 1). Aortic pathology represented 4.4% (n = 17) of all 384 deaths. Twelve were caused by dissection, and 5 were caused by aneurysm rupture. In all 17 of these cases, the aortic pathology was noted by the medical examiner as the unequivocal cause of death. Only 2 of the 17 cases of sudden death from aortic pathology had known preexisting diagnosis of aortic pathology as confirmed by interview with family and review of medical records. Evaluation of the ED records to determine antemortem suspicion for aortic pathology indi- cated that in 2 of the 12 cases of dissection, the ED physician documented suspicion for dissection, and in one of the 5 aneurysm cases, the ED physician documented suspicion for aneurysm. In all 3 of these cases, the patients had a pulse upon

Table 3 Clinical characteristics of death from aortic causes compared with death from nonaortic medical causes

arrival to the ED, or in the aneurysm case, upon return of spontaneous circulation in the ED. Five (29.4%) of the 17 patients experiencing aortic sudden death had a pulse at the time of EMS arrival, and 4 (23.5%) of the 17 had a documented pulse upon arrival to the ED. Patients with aortic dissection presented with abdominal pain (n = 1), headache (n = 1), altered mental status (n = 2), syncope (n = 1), seizures (n = 2), diaphoresis (n = 1), and left hemiparesis with right neck pain (n = 1). Patients with death from aortic aneurysm presented with abdominal pain (n = 2; Table 2).

When comparing the patients with aortic causes of death with the patients with other causes of medical nontraumatic sudden death, several differences were noted. The patients with aortic causes of death were statistically older (mean age, 51.1 vs 45.7; 95% CI for difference, 0.4%-10.3%). They were also more likely to have a pulse in the ED (23.5% vs 2.8%; 95% CI for difference, 0.5%-41.0%), and an arrest rhythm of pulseless electrical activity (PEA; 41.2% vs 12.3%; 95% CI for difference, 5.3%-52.5%). In addition, their deaths were more likely to be witnessed by a medical provider (35.3% vs 11.7%; 95% CI for difference, 0.6%-46.5%; Table 3).

Discussion

To our knowledge this is the first case series and comparison study of autopsy-proven sudden death from acute aortic emergencies in the ED setting. Despite significant teaching that

Aortic death		sudden	Nonaortic sudden death		Difference between groups	95% CI for difference
Mean age (y)	51.1 (46.2-55.8)		45.7 (44.6-46.7)		5.4	0.4 to 10.3
Men	12/17	(70.6%)	269/367 (73.3%)		-2.7%	-24.8% to 19.4%
Chest pain	4/17	(23.5%)	83/367 (22.6%)		0.9%	-19.7% to 21.5%
Abdominal pain	3/17	(17.6%)	30/367 (8.2%)		9.4%	-8.9% to 27.8%
Neurological symptom	3/17	(17.6%)	42/367 (11.4%)		6.2%	-12.2% to 24.6%
ED pulse upon arrival	4/17	(23.5%)	10/361	(2.8%)	20.7%	0.5% to 41.0%
PEA as first arrest rhythm	7/17	(41.2%)	45/367 (12.3%)		28.9%	5.3% to 52.5%
Witnessed arrest	14/17	(82.4%)	234/367 (63.8%)		18.6%	-0.2% to 37.4%
Witnessed arrest by a medical provider	6/17	(35.3%)	43/367 (11.7%)		23.6%	0.6% to 46.5%
ROSC in ED	3/17	(17.6%)	13/367 (3.5%)		14.1%	-4.1% to 32.3%
Statistically significant differences in bold.

aortic “catastrophies” can lead to sudden death, little is known about the clinical and pathological characteristics of these events. Our report suggests several significant findings.

Death from aortic disease is not instantaneous in these subjects. We describe that more than half of these patients (9/ 17) had prodromal symptoms of chest pain, abdominal pain, or neurological dysfunction, suggesting that recognition of aortic pathology may be possible. In addition, a third of the arrests were witnessed by EMS or the ED physician. A gradual evolving deterioration arrest is also supported by the preponderance of PEA as the primary rhythm of sudden death from aortic pathology, consistent with previous reports [1]. Pulseless electrical activity was statistically more prevalent as the primary arrest rhythm from aortic causes as compared with nonaortic causes (41.2% vs 12.3%, Table 3).

Textbooks and previous studies typically suggest that death from aortic dissection can occur from retrograde dissection and resultant hemopericardium and tamponade [1,5,8]. This series provides evidence supporting this mechanism as a final common pathway of death from dissection. Of the12 cases of dissection in this series, 8 had hemopericardium at autopsy. Three others had mediastinal or pleural hemorrhage.

Despite the fact that our study was not aimed to provide power to discriminate between aortic and nonaortic causes of sudden death, several trends and hypothesis-generating differences were observed. Patients with death from aortic causes were statistically more likely to have PEA as the arrest rhythm, an arrest witnessed by either an ED physician or EMS personnel, and a pulse at the time of ED arrival. It is unlikely that clinicians would use arrest rhythm alone to diagnose an aortic cause of arrest, but these findings may provide support for clinicians to consider aortic pathology as among the most likely considered diagnoses. This may have an implication if return of spontaneous circulation occurs or if it prompts additional bedside imaging.

These data support the use of bedside ED ultrasound as a first measure in shock suggestive of dissection or any PEA cardiac arrest to look for evidence of tamponade [9] or free fluid in abdomen. We note that two thirds of the dissection subjects had hemopericardium, and all of the aneurysm subjects had hemoperitoneum. Although needle decompres- sion may only be temporizing, it is a recommended immediate therapy for suspected tamponade and may be the only way to prevent these patients from deteriorating immediately to unsalvageable cardiac arrest [10].

Our report is limited in several ways. This is a select sample of patients who were referred to the ME’s office for evaluation of cause of sudden death. It is possible and indeed likely that this sample is not representative of all subjects with outpatient sudden death from aortic pathology because of exclusion of patients older than 65 years. In this ME system and most others, patients with nontraumatic medical arrest older than 65 years rarely, if ever, had an autopsy performed, and as the outcome focus of our work was clear,

unambiguous determination of cause of death, this cutoff was used. This work likely underestimates both the age and the true prevalence of these diseases as cause of death in ED patients because of this fact. This is also derived from a single metropolitan area and may not be generalizable to other locations. Despite this possibility, we note that our sample was ethnically diverse and came from more than 6 hospitals including academic and community centers. Finally, we note that because of the number of subjects with aortic pathology, our work is not adequately powered to measure all clinically significant potential differences in characteristics between aortic and nonaortic medical sudden death. Future work pooling data from several sites will improve both generalizability and power.

In conclusion, all 384 patients in this sample were brought to an ED, had an unexpected cardiac arrest, and had attempts at resuscitation with autopsy-determined cause of death. We report a prevalence of aortic pathology as causal in 4.4% of these subjects. Of the patients with aortic causes of sudden death, more than half had prodromal symptoms of chest pain, abdominal pain, or neurological dysfunction. Pulseless electrical activity, as the arrest rhythm, was seen in more than a third of subjects with aortic causes of death, and a third had their arrest witnessed by either an ED physician or an EMS provider.

References

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