The Wells test for Pulmonary Embolism. Blood clot risks in the surgical patient.

Posted on February 16, 2021

I evaluate all my patients for blood clot risk before surgery using the Caprini risk score. I use compression on your legs during the surgery to keep your blood flow moving. I focus on pain control and encourage you to get out of bed and move after surgery. If you need to go on a long car trip or plane ride after surgery for the first 3-4 weeks, I tell you to get up and move around every hour or two.

Even with all of this, you are still at risk.

So how do you know if you have a pulmonary embolism?

Come in, the Wells test. This is not to predict your risk of a blood clot like the Caprini score. This is to try to figure out if you have a pulmonary embolism.  A score of 4 or higher on the Wells test indicates a PE is likely. Why am I writing about this? Because pulmonary embolism is totally tricky. The symptoms are super vague: short of breath, pain with deep breathing, elevated heart rate. I have had few episodes of this, but one patient presented 10 days out with a complaint of “shoulder pain.” Your oxygen saturation level may be normal. You may not have a sign of a blood clot in your leg. The timing can be a week out or a month out from your surgery.

Wells test:

  • Clinical signs and symptoms of DVT  blood clot in your leg SCORE 3
  • PE is #1 diagnosis OR equally likely  SCORE 3
  • Heart rate > 100   SCORE 1.5
  • Immobilization at least 3 days OR surgery in the previous 4 weeks SCORE 1.5
  • Previous, objectively diagnosed PE or DVT  SCORE 1.5
  • Hemoptysis (coughing up blood) SCORE 1
  • Malignancy w/ treatment within 6 months or palliative SCORE 1
Again, a score of 4 or more means PE is likely. I keep thinking of this during this time of Covid. When they do autopsies, they find blood clots. Everywhere. I recently talked to a friend who had a friend with Covid and said he felt okay afterwards except, “the only weird thing is that his resting heartrate went from 55 to over a 100.” When I read this, I think he must have microclots in his lungs.
Why care?
Because even if a pulmonary embolus doesn’t kill you, it is impairing oxygen exchange. It can be a sign there are clots elsewhere. There may still be clot in your leg, and a big clot could block enough of the lung to kill you.