QA of the Month: October 2013

Dyspnea on Exertion

Congrats to Dr. Steve Foy!

Case

77 yo male, h/o CHF, a-fib and PE, on Coumadin, presents with 1 week increasing dyspnea on exertion, periodic exertional non-radiating substernal chest pain, and increased leg swelling. Last episode of chest pain 12 hours prior. 

Vitals

HR 95 RR 20 BP 141/84 SpO2 96% RA T 36.6

Physical Exam

Bilateral rales. 2+ pitting edema to bilateral LE’s. EKG: Afib with rate 108. No ST changes. T-wave flattening inferiorly. 
Trop at 0.26. Creatinine slightly elevated to 1.5, over baseline of 1.1. CXR pulmonary edema, stable large cardiomediastinal silhouette. 

The ED providers (Dr. Mianzo and Elder) were not entirely certain that this was a straightforward CHF exacerbation. The patient was having increasingly frequent falls, and had ‘old’ facial droop for which he never sought care. Given his large cardiomediastinal silouhette, and subtle neurologic findings, they were concerned for previously unidentified aortic pathology. The patient, however, was concerned about ionizing radiation/elevated Cr, and refused CT. NSTEMI diagnosed, Hospitalist and Cardiology involved with recommendation for starting heparin, but they did not order it due to concerns for dissection. Bedside cardiac echo performed by Dr. Elder for chest pain and shortness of breath (see image below). 

Bedside echo reveals no pericardial effusion, moderately decreased contractility, and grossly normal chamber size. The above parasternal long view also shows the ascending aorta/aortic root. With increased depth, the circular (transverse) descending thoracic aorta will be seen just deep to the heart. We notice here that the ascending aorta beyond the Sinus of Valsalva (Measurement B) is large, and likely larger than the ‘normal’ ascending thoracic aorta size of 4cm. 

At this point, Dr. Foy evaluated the abdominal aorta. Further focused questioning revealed intermittent abdominal ‘cramps’ over the past few days. 

Within the longitudinal aorta imaged above we see a flap. In real time video, this flap was bouncing around! Transverse measurements of the proximal abdominal aorta were over 3 cm as well (abdominal aortic aneurysm defined as above 3cm). Color Doppler reveals a true and false lumen as seen below! 

Heparin drip for NSTEMI was withheld. This caused further discussion with patient regarding obtaining CTA, who agreed after seeing the images. The CTA revealed extensive type A aortic dissection from aortic root, throughout the entire aorta beyond the bilateral iliacs, involving all 3 great vessels off the aortic arch, the SMA, and left renal artery. CT surgery consulted, recommending non-surgical management given high perioperative risk. Aggressive medical management was recommended instead, and no anticoagulation for NSTEMI. The patient remains hospitalized, but is improving and recently transitioned to the floor from the MICU. 

Key learning points

  1. Goal-directed Echo:
    • Required views for credit: At least 3 different views (subxiphoid, parasternal long, parasternal short, apical 4-chamber)
    • ED scope of practice for cardiac echo:
      • Pericardial effusion/tamponade
      • Global contractility
      • Relative chamber sizes (including RV strain).
    • Other echo abnormalities such as valvular dysfunction and regional wall motion abnormalities are beyond our scope of practice, but if we notice an abnormality we should act on it (further imaging, specialty consultation)
    • ‘Normal’ ascending thoracic aorta is less than 4cm (PSL view)
    • ‘Normal’ descending thoracic aorta (PSL view) is <2cm (2-3cm is ectatic; >3cm is aneurysmal)
  2. Abdominal Aorta
    • Required views include:
      • Transverse view
        • Proximal, mid, and distal aorta through to bifurcation—
        • Measurements from outer wall to outer wall at widest point
      • Longitudinal view
    • Normal abdominal aorta is less than 2cm (2-3cm is ectatic; >3cm is aneurysmal). Normal iliac arteries is <1.5cm
  3. Aortic Dissection: Ultrasound is 65-80% sensitive for abdominal aortic dissection, but highly specific
  4. Aortic Aneurysm: Ultrasound is >90% sensitive for abdominal aortic aneurysm, but does not assess for rupture (this involves clinical correlation and your FAST scan will be negative due to retroperitoneal leak of most aneurysmal ruptures)

Kudos to Dr. Foy!