After recently seeing a patient who came in with upper extremity swelling in the setting of chronic HD with an A/V fistula in the same arm, and a negative U/S for DVT in the upper extremity, I was wondering about two questions — 1.) What is the sensitivity of U/S for DVT of the upper extremity, and more proximal central veins, and 2.) What is the risk profile of these thrombii when found? How many will lead to badness we worry about, e.g. pulmonary embolism?
Here’s what I found:
In terms of upper extremity DVT:
– Hingorani et al published comparative rates of PE in UE DVT v. LE, finding a prevalence rate of pulmonary embolism of 17% from UEDVT compared with 8% from lower extremity deep venous thrombosis. Another paper combining data from nine studies reported a 13% PE rate (Kommareddy A et al. Semin Thromb Hemost 2002; 28:89–99).
Our patient was found to *not* have an upper extremity DVT per the initial U/S, but as we discussed, it seemed more likely that (especially given his neck and facial swelling, which is almost universally found in these patients) that any thrombosis he had would be more proximal as it had been in the past, so ultrasonography may not have been the best first imaging test — according to a J. Ultrasound Medicine paper regarding UE DVT screening, “centrally situated veins, including the medial segment of the subclavian vein, the brachiocephalic vein, and their confluence with the superior vena cava, may be difficult to visualize” — and perhaps would be better evaluated with MR Venography or contrast venography.
So for more central clots, e.g. SVC or brachiocephalic veins, what are the associated risks?
– Otten et al. state in a 2003 Chest article, “Thromboembolic Disease Involving the Superior Vena Cava and Brachiocephalic Veins”: “The frequency of isolated thrombosis of the SVC or brachiocephalic veins that we report probably grossly underestimates the true incidence, because the test that is usually performed in symptomatic patients, color duplex Doppler ultrasonography, cannot image the SVC and proximal segment of the brachiocephalic veins.”
– In this article, they report an 8.7% rate of PE from SVC/brachiocephalic DVTs. A larger series of 33 patients with thromboembolic disease involving the BC or SVC reported 36% of these patients as having symptomatic PE, with four of these being fatal.
Lastly, but probably most importantly, Shennib et al. reported in May of this year a patient who suffered an UE DVT after aggressively utilizing a “popular modified, oscillating dumbbell”, more commonly known as a Shake Weight. So please consider screening for Shake Weight usage as a risk factor in any patients being assessed for UE DVT.
What I found interesting about this was the incredible variability in reported incidence of serious complications, and conclusions in terms of what the risk of complication was — vascular surgery literature tended to minimize these complications relative to hematology literature. I’m not sure if this reflects just different patient populations the two specialties are exposed to, or the fact that these problems are often found in the setting of prior vascular interventions, but it’s interesting to think about the implications of widely-disparate risk estimates coming out of different bodies of literature.