For this article I consulted with Dr. Moji Gashti, Chief, Division of Vascular Surgery, Department of Surgery, Union Memorial Hospital, Baltimore, MD.
Perhaps you’ve read that half of DVTs don’t present with symptoms, but what about large DVTs?
“A large DVT in a proximal vein (popliteal, femoral, iliac veins) most often will be symptomatic with at least edema and perhaps pain,” says Dr. Gashti.
Popliteal = behind the knee
Femoral = main artery of thigh
Iliac = pelvic vein
“Some people can have duplicate femoropopliteal veins and even IVC [major vein that goes into the heart], and if they develop a large DVT in one of the two veins, they may not be symptomatic. Others may have developed significant collaterals in the past, perhaps from an old DVT, and again may not present with significant symptoms.”
Collaterals refer to development of additional veins to compensate for deficient veins.
“In one study, about 300 patients in the SICU, asymptomatic for DVT, were scanned and 7.5% had major proximal DVT. An orthopedic patient cohort was studied pre- and post-surgery. All were asymptomatic for DVT; 2.5% of patients pre-op had proximal DVT and over 16% post-op.”
Of course, it’s logical to wonder how many of these asymptomatic deep vein thromboses would have eventually began producing symptoms if they were not discovered, and therefore not treated.
Dr. Gashti continues, “So you can see that a significant number of even proximal DVTs can remain asymptomatic. The question is what is the significance of not treating these patients and should we study all of them?
“These are surgical patients; but to know the exact number of asymptomatic DVTs, a large number of people need to be randomly studied!
“The most common symptoms of large symptomatic DVTs in the acute setting are pain and swelling [edema]. Discoloration may occur later as the result of postphlebitic syndrome.
“Interestingly in another study where patients who had symptomatic, confirmed DVT in one limb, 5% had proximal DVT in the asymptomatic limb.”
-Top 4 causes of swollen legs after surgery