AHA guidelines on Thoracic Aortic Disease (March 2010)
sensitivity of aha dissection risk score tested on IRAD case database (Circulation 2011;123:2213)
Dissection lecture complaints above and below the diaphragm vague neurologic complaints any chest pain with focal neurologic deficit-dissection migrating pain risk factors-htn/family/connective tissue disease/sleep apena/pregnancy document no aortic murmur, pulses equal bilaterally COMPLAINT SIGN INTEGRATION
HTN is #1 risk factor
Marfan’s, ehlers-danlos, bicuspid aortic valve, pregnancy predisposes, Turners, cocaine
Heart sways from side to side with each beat, aorta is untethered between arch + L subclavian
May present as syncope, pericardial effusion/Tamponade, spinal cord ischemia,
A small tear forms between the media and adventitia. The outer wall encompassing the dissection is exceedingly thin and prone to rupture. If a second tear forms which allows the blood to reenter the lumen, survival actually increases. If chronic, an aneurysm may form
The adventitia has a ton of autonomic innervation, this is why patients get sympathetic surge
Place radial or L femoral a-line (reserve the right for bypass)
Lower the heart rate to 60-75, then lower SBP to 100-120/MAP 60-75
Goals of drug therapy
Reduce dp/dt (velocity of LV contraction; rate of rise of aortic pressure) = Reduce Heart Rate, and Inotropy
Reduce BP
I-Ascending and arch
II-Ascending
III-descending
Stanford Classification
A-Ascending (surgical)
B-Not ascending (medical)
Almost all have chest or back pain
Anterior-ascending, jaw or neck-arch, scapular-descending
Three clinical variables (Arch Int Medicine 2000, 160)
- Aortic pain of tearing or ripping character
- Mediastinal or Aortic Widening
- Pulse or Blood Pressure Differentials
Chest X-Ray
- 18 pts c AD, 25 pts c MI 2 Radiologists blinded to dx, but knows it is one of the two Looked for 9 x-ray signs Only 1/3 of MI X-rays had no signs of AD 9/50 MIs misdiagnosed as AD 7/36 Ads misdiagnosed as MI (J Thorac Imag 8:2, 1993)
- Only 25% of proven AD had signs seen on prospective evaluation of the films Only 50% had evidence when radiologists went back to the films after knowing the diagnosis (Radiology 193:3, 1994)
- Only 1 death in a case of Lysis with ST elevations (Am Heart J 128:1234-7, 1994)
The International Registry of Acute Aortic Dissection published in JAMA does for acute aortic dissection what PIOPED did for pulmonary
embolism: provide clinical insight into an important entity in emergency medicine whose presentation is not always straightforward.
Prompted by advances in imaging and surgical techniques, IRAD enrolled 464 patients with acute dissection. Several of the
findings contradict conventional wisdom and must be kept in mind in the ED:
Description of the Pain
Patients described the presenting pain more often as sharp
rather than tearing or ripping (64% vs. 51%). Migratory pain has
been described as characteristic but was noted in only 16% of
patients. Pain is at maximum intensity at onset
Pulse Deficit:
Only 15% of patients exhibited a pulse deficit, 19% with type A dissections and 9% with type B
Mediastinal Widening:
Only 62% of patients showed mediastinal widening on the Chest
X-ray. More than one fifth had neither a widened mediastinum nor an
abnormal aortic contour
Murmur of AR:
The murmur of aortic regurgitation, said to be found in the
majority of patients in type A dissections due to involvement of the
aortic root was found in only 44% of patients with type A dissection
Electrocardiogram:
Normal EKG finding have been suggested to be a marker to steer
physicians toward a diagnosis of dissection and away from myocardial
ischemia, usually the major differential diagnosis. Normal EKG
findings were present in less than a third of IRAD patients,
suggesting that this test is not especially helpful in
distinguishing the two.
Of note, CT scan was the initial imaging modality in 61% of
patients, with echocardiogram (TEE and/or TTE) used initially in
33%. Aortography, previously the standard, was used infrequently,
and rarely as the initial study (4%).
Reference: JAMA 2000; 283: 897-903
Interarm Difference
3 ½ % had >20 difference (J Hyperten 20:1089, June 2002) and 18% >10 (Acad Emerg Med 9:342, 2002)
Physical Exam and C-XR are not sufficient for evaluation (JAMA 287 (17))
Syncope, tamponade, CVA, spinal cord ischemia, pulse discrepancies, aortic regurg
C-XR is abnormal 80-90% of time. Calcification c separation, pleural effusion
Use TEE or CT
Differential-MI, PE, Pericarditis
Treatment
Maintain systolic of 100-120
B-Block to a systolic of 110 first, then if BP still high, add nitroprusside
Labetolol can also be used
Use Trimethaphan camsylate (Arfonad) 1-15 mg/min, a powerful ganglionic blocker which decreases bp and inotropy, if pt can not receive b-blockers. Side effects include orthostatic hypotension, blurred vision, urinary retention, and ileus.
C-XR Findings (12% have normal X-Ray)
1. Widening of the superior mediastinum
2. Separation of the calcified intima from the outermost portion of the aorta by more than 5 mm
3. Loss of aortic knob
4. Displacement of trachea or NG tube to the right
5. Downward displacement of the left mainstem bronchus
6. Disparity in the caliber of the ascending and descending aorta
7. Apical capping
8. Pleural effusion (most commonly left sided)
9. Localized bulge in the aorta
D-Dimer
(Eur Heart J D-dimer in ruling out Sodeck G) .1 ug/cc had 100% sens in a SR and prospective validation; 0.5 ug/ml would have missed one pt in a pooling of the trials
another pooled MA showed sens 95% (91-98%)
specificity ranged from 40-100%
New prospective multicenter in pts with suspected but not proven (220 pts, 87 had dissection) used cutoff 500 ng/ml. neg LR 0.07 (Circ 2009;119:2702)
Meta-analysis of usefulness of d-dimer to diagnose acute aortic dissection. (Am J Cardiol. 2011 Apr 15;107(8):1227-34.)
Plasma DD may thus be used to identify subjects who are unlikely to benefit from further aortic imaging.
Aortic Intramural Hematoma
No intimal disruption
Giving Heparin/Lytics
Retrospective study (American J EM 2005;23:439)
2 deaths in anticoagulated and 2 in non
Arch Intern Med. 2006 Jul 10;166(13):1350-6. Related Articles, Links Diagnostic Accuracy of Transesophageal Echocardiography, Helical Computed Tomography, and Magnetic Resonance Imaging for Suspected Thoracic Aortic Dissection: Systematic Review and Meta-analysis. Shiga T, Wajima Z, Apfel CC, Inoue T, Ohe Y. Department of Anesthesiology, Toho University Ohashi Medical Center, Tokyo, Japan. BACKGROUND: Patients with suspected thoracic aortic dissection require early and accurate diagnosis. Aortography has been replaced by less invasive imaging techniques including transesophageal echocardiography (TEE), helical computed tomography (CT), and magnetic resonance imaging (MRI); however, accuracies have varied from trial to trial, and which imaging technique should be applied to which risk population remains unclear. We systematically reviewed the diagnostic accuracy of these imaging techniques in patients with suspected thoracic aortic dissection. METHODS: Published English-language reports on the diagnosis of thoracic aortic dissection by TEE, helical CT, or MRI were identified from electronic databases. Sensitivity, specificity, and positive and negative likelihood ratios were pooled in a random-effects model. RESULTS: Sixteen studies involving a total of 1139 patients were selected. Pooled sensitivity (98%-100%) and specificity (95%-98%) were comparable between imaging techniques. The pooled positive likelihood ratio appeared to be higher for MRI (positive likelihood ratio, 25.3; 95% confidence interval, 11.1-57.1) than for TEE (14.1; 6.0-33.2) or helical CT (13.9; 4.2-46.0). If a patient had shown a 50% pretest probability of thoracic aortic dissection (high risk), he or she had a 93% to 96% posttest probability of thoracic aortic dissection following a positive result of each imaging test. If a patient had a 5% pretest probability of thoracic aortic dissection (low risk), he or she had a 0.1% to 0.3% posttest probability of thoracic aortic dissection following a negative result of each imaging test. CONCLUSION: All 3 imaging techniques, ie, TEE, helical CT, and MRI, yield clinically equally reliable diagnostic values for confirming or ruling out thoracic aortic dissection.
abd dissection isolated
Isolated abd dissection (J Vasc Surg 2002;36:205)
Marfan (50%)
Ehlers-DanlosTurner
Bicuspid aortic valve
Familial aortic dissection (dominantly)
Pregnancy/puerperium
Catheterization
High blood pressure (both chronic and acutesympathetic surge)
Weight lifting
Cocaine/crack/methamphetamine
If you see bifid pulse ox in the right setting, think dissection (Emergency Medicine Journal 2009;26:634)
Concominant MI with Aortic Dissection
Painless Acute Aortic Dissection
from emedhomeClinical experience and recent literature has made it quite clear that although textbook presentations of an acute aortic dissection may occasionally occur, they tend to be the exception rather than the rule. The atypical is really the typical.Emergency Physicians should be bear in mind that an acute aortic dissection (AAD) may present without pain. In one recent series of 977 patients (1), 63 (6.4%) had painless AAD. Furthermore, the initial pain of aortic dissection may be followed by a pain-free interval lasting from hours to days, ending with the return of pain. This return of pain after a pain-free interval is an ominous sign and usually indicates an impending rupture (3).
So how does the clinician even consider the diagnosis of AAD when there is no presenting chest or back pain? Think of an acute aortic dissection when a patient presents to the ED with:
- Syncope – In the case series referenced above (1), syncope was the presenting complaint in 1/3 of the painless AAD cases. The underlying pathophysiology of syncope may be related to proximal rupture into the pericardium with resultant tamponade. Add AAD to your differential diagnosis of unexplained syncope.
- Stroke – Focal neurologic deficits occur in a significant number of cases of Acute Aortic Dissection. In the Mayo case series, 11% of cases of painless AAD presented with an acute stroke. In addition, patients who present aphasic secondary to an acute stroke may be unable to communicate a chest pain/back pain history.
- Unexplained lower extremity weakness/paralysis – Spinal cord involvement is attributed to perfusion deficit in the great radicular artery of Adamkiewicz, a large branch from the aorta that supplies the lower thoracic and lumbar spinal cord.
References:(1) Park SW, et al. Mayo Clin Proc 2004;79: 1252-1257. (2) Hagan PG, et al. JAMA 2000; 283: 897-903. (3) Meszaros I, et al. Chest 2000 May;117: 1271-8. (4) Rosen SA. Ann Emerg Med 1988;17:840-2.(5) Baydin A, et al. Mt Sinai J Med. 2006;73: 1129-31.(6) Ayrik C, et al. Emerg Med J. 2006; 23: e24.