Would you recommend pharmacologic treatment with levothyroxine for a patient with subclinical hypothyroidism and CAD s/p stent placement even if the TSH is less than 10mIU/L, given a described association with reduced risk for major adverse cardiovascular events with treatment?

As always, the treatment should be individualized. The treatment of subclinical hypothyroidism can be very different in younger patients compared to the elderly. According to the European Thyroid Association, initially, if the serum TSH is elevated in the range of 4 to 10 but with a normal Free T4, such patients should be investigated in 2 to 3 months with repeat Free T4 and TSH, along with Thyroid antibodies. In younger patients (age <65-70), if TSH is >10, treatment with L-Thyroxine is recommended. In younger patients with TSH <10, a trial of Thyroxine is recommended, and response to treatment should be evaluated in 3 to 4 months. If no improvement in symptoms is noted, stopping treatment with thyroxine should be considered. Older patient...

If the CAD has been corrected by the stent, there is no risk in treating subclinical hypothyroidism with Levothyroxine. Questions to ask the patient are if their angina sx have resolved after stent placement, whether they get angina with physical activity, and what level of physical activity they can do. The risk of angina with T4 therapy is the increase in oxygen demand with an increase in HR and force of contraction with T4 therapy. If they can exercise without pain, just replace with low dose T4 (25 mcg/day or less) and slowly titrate up on the dose. Don't leave them hypothyroid because it may develop into overt hypothyroidism, which will be much harder to treat!