Suspected Aortic Dissection and Other Aortic Disorders: Multi–Detector Row CT in 373 Cases in the Emergency Setting Robert G. Hayter, BS, James T. Rhea, MD, Andrew Small, MD, Faranak S. Tafazoli, MD and Robert A. Novelline, MD Int. 王富弘

Introduction Acute life-threatening aortic disorders Acute aortic dissection, acute aortic intramural hematoma, and acute penetrating aortic ulcer,… patient's symptoms can vary markedly according to the organ systems affected  clinical diagnosis remains challenging

Introduction Aortic dissection five to 27 cases per million people per year as many as one-third of cases are not diagnosed most common aortic disorder requiring surgery 6th and 7th decades of life 3:1 male-to-female predominance, the most important risk  hypertension and medial degeneration of the aortic wall

Introduction Aortic intramural hematoma Penetrating aortic ulceration lack of detectable intimomedial flap lack of direct flow communication between the true and false lumina 5%–20% of all acute aortic disorders Penetrating aortic ulceration increased risk of progression to acute aortic rupture and other acute aortic disorders 2.3% of cases of suspected aortic dissection ; 52% of aortic intramural hematomas

Aortic intramural hematoma

Penetrating aortic ulceration

Introduction Mortality A delayed or missed diagnosis of acute aortic dissection, acute aortic intramural hematoma, when untreated : >1% per hour during the first 24 hours after onset 80% by 2 weeks

Introduction Imaging modalities Purpose conventional aortography, ultrasonography (US) computed tomography (CT) magnetic resonance (MR) imaging Purpose retrospectively review our experience in using an aortic dissection multi–detector row CT protocol in the emergency setting

MATERIALS AND METHODS Patients: January 1, 2002 ~ June 30, 2003 in ER of MGH not experienced trauma suspected aortic aortic disorders underwent multi–detector row CT all cases had been identified by the authors Exclude Inpatients other clinically suspected problems with associated findings of acute aortic disorder The cases be inadequate on the basis of the scanning protocol or the final images obtained

MATERIALS AND METHODS aortic dissection multi–detector row CT protocol: nonenhanced / contrast enhanced; chest, abdominal, and pelvic images nonenhanced CT hyperattenuating crescentic hematoma produced by aortic intramural hematomas aortic intramural hematomas acute aortic disorder contrast-enhanced transverse CT 2-minute-delay scanning: free blood flow between the true and false lumina coronal and sagittal aortic reformations

MATERIALS AND METHODS Definitions Diagnostic tool Positive case multi–detector row CT, aortography, MR angiography, transesophageal echocardiography (TEE), or transthoracic echocardiography Positive case acute aortic dissection, acute aortic intramural hematoma, acute penetrating aortic ulcer, new or enlarging aortic aneurysm acute aortic rupture

MATERIALS AND METHODS Acute aortic disorders acute aortic dissection, acute aortic intramural hematoma, acute penetrating aortic ulcer, imaging findings criteria + < 2 weeks of symptoms at the time of scanning, or changed findings on CT images compared to previous New or enlarging aortic aneurysm without associated findings on previously images thoracic aortic dilatations >= 5 cm in diameter, or abdominal aortic dilatations >= 3 cm Acute aortic rupture extravasation of (contrast material / blood) (beyond the adventitia / within the pericardial sac)

MATERIALS AND METHODS Definitions Chronic aortic dissections, aortic intramural hematomas, and penetrating aortic ulcers more than 2 weeks of symptoms at the time of scanning Stable aortic dissections, aortic intramural hematomas, and penetrating aortic ulcers unchanged findings on CT images compared with previously images or finding of a calcified outer wall in the false lumen criteria for acute aortic disorder were confirmed by using "hard" data: surgical and pathologic diagnoses, or "soft" data: findings at clinical follow-up and any subsequent imaging

Data and Statistical Analyses Images were reviewed independently by two authors (J.T.R., R.A.N.) accuracy analysis, multi–detector row CT findings were compared with available aortographic, MR angiographic, TEE, transthoracic echocardiographic, surgical, and pathologic findings; with the discharge diagnoses, clinical follow-up findings sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the AD multi–detector row CT protocol were calculated by using two-way contingency table analysis one case interpreted as indeterminate not included

Results Type A versus Type B Aortic Disorders TT Type A 71.6y/o^11   TT Type A 71.6y/o^11 M 13 F 4 17 Type B 73.2y/o^16.1 M 10 F 22 32 Acute Aortic A 75.7y/o^9.8 M 22 44 Acute Aortic R 76y/o^9.5 M 7 11

Results history of aortic aneurysm and hypertension: now presenting   Ascending thoracic aortic aneurysms Descending thoracic aortic aneurysms Abdominal aortic aneurysms TT Type A 3 2 5 17 Type B 1 9 32 Acute Aortic A 4 10 44 Acute Aortic R 6 11 total 13 12 29 38

Results history of aortic diseases: Repaired Ascending thoracic AA/R   Ascending thoracic AA/R Descending thoracic AA/R Abdominal AA/R type A AD repair Type B AD R AVR TT Type A 2 1 17 Type B 6 3 5 32 Acute Aortic A 44 Acute Aortic R 11 total 7 15/22 9 16

Results Multi–Detector Row CT Interpretation of 373 Cases of Suspected Aortic Dissection and Other Aortic Disorders

Results Image exam: one TEE examination: acute aortic intramural hematoma that was missed at multi–detector row CT one case interpreted as indeterminate row CT, no acute aortic disorder was found at follow-up TEE   initial imaging modality addition multi–detector row CT 367 cardiac US TEE 6 36 TTE 117 aortography 4 MR 15

Results Statistical Findings

Results Alternative Findings Identified with Aortic Dissection Multi–Detector Row CT Protocol

Results Characteristics of 67 Cases Positive for Acute Aortic Disorder

Results IM history: Marfan syndrome Ehlers-Danlos syndrome   Marfan syndrome Ehlers-Danlos syndrome Hypertension Diabetes mellitus bicuspid or unicommissural aortic valves TT Type A - 12 1 17 Type B 3 21 2 32 Acute Aortic A 30 4 44 Acute Aortic R 8 11

Results Presenting Symptoms Type A Type B Acute AA Acute AR TT   Type A Type B Acute AA Acute AR TT Chest pain 11 22 9 217 Back pain 4 12 16 1 162 Abd. pain 3 54 Syncope 10 SOB 2 21 Miscellaneous 19 Un-equal BP 5 Tearing chest pain 17 32 44

Results BP and EKG Type A Type B Acute AA Acute AR TT SBP<80 1   Type A Type B Acute AA Acute AR TT SBP<80 1 SBP 81~99 2 SBP 100~139 7 8 14 4 SBP>140 13 15 BP data available 12 23 31 Unequal BP Nonspecific ST-T 17 22 old Q waves 3 32 44 11

Results Radiographic Findings Aortic calcification, displacement of the aorta, displacement of the mediastinum, and intimal calcification were rare findings   Type A Type B Acute AA Acute AR TT widened mediastinum 8 4 7 Cardiac silhouette enlargement 6 3 Thoracic aortic ectasia 10 tortuous aorta 5 12 1 Pleural effusion No wide Med. 16 30 No T A ectasia 14 24 17 32 44 11

Results Treatments and Outcomes Type A Type B Acute AA Acute AR TT   Type A Type B Acute AA Acute AR TT Emergent surgical repair of the aorta 11 6 10 discharged in stable 14 26 41 8 died during hospitalization 2 3 overall mortality rate 4 17 32 44 67

Results Cost Calculations

DISCUSSION DeBakey Stanford-Daily system Type 1 aortic dissection involves both the ascending and the descending aorta. Type 2 : ascending aorta and extends to the origin of the brachiocephalic artery. Type 3 : descending aorta, beginning at the origin of the left subclavian artery Stanford-Daily system Type A involves the : the ascending aorta and beyond. Type B : confined to the descending aorta, beginning at the origin of the left subclavian artery surgery for type A and nonsurgical therapy for type B

DISCUSSION

DISCUSSION Aortography aortic dissection penetrating aortic ulcers 88% sensitivity, 94% specificity, a 96% positive predictive value, and an 84% negative predictive value penetrating aortic ulcers 83% sensitive not be able to depict aortic intramural hematomas or many of the other potential alternative findings expensive, time-consuming, and associated with higher morbidity

DISCUSSION CT ~100% sensitivity and specificity for detection of aortic dissection and aortic intramural hematoma Other published data show CT to have 65% sensitivity for detection of penetrating aortic ulcers aortic dissection CT protocols are more than adequately reliable for the detection of true aortic dissection and other aortic disorders

DISCUSSION US techniques transthoracic echocardiography TEE sensitivity for detection of type A (60%–80%) and type B (50%) aortic dissections and 90% specificity for detection of both types TEE requires esophageal intubation sensitivity of 97%–99%, specificity of 99%–100% in the detection of aortic dissection sensitivity of 90%–100% and a specificity of 91%–100% for detection of aortic intramural hematomas sensitivity of 61%–83% for detection of penetrating aortic ulcers lead to increased systolic blood pressure acute aortic rupture

DISCUSSION MR sensitivity (95%–100%) specificity (94%–98%) for detection of aortic dissection sensitivity of 100% for detection of aortic intramural hematoma sensitivity of 86% for detection of penetrating aortic ulcer requires approximately 30 minutes more expensive than CT not readily available in many emergency departments

DISCUSSION CT—is now the primary imaging modality Exceptions to this standard arise when patient instability, poor renal function, and/or allergy to iodinated contrast material too unstable  TEE (need skillful in ~ 5min) impaired renal function or iodinated contrast material allergy  MR

DISCUSSION limitations of the investigation limited application of the data to other populations lack of a clear definition of what may increased use of the aortic dissection multi–detector row CT protocol lack of a clear definition retrospective design

positivity rate of 18%, when compared with the accepted positivity rate of 1% for detection of traumatic aortic injury with CT, suggests that the described aortic dissection multi–detector row CT protocol is not overused no reliable data derived from the presenting symptoms and signs, radiographic findings, or electrocardiographic findings to aid in the further screening of patients physician must keep a high clinical index of suspicion for aortic aortic disorders because we have CT