Is there a contraindication to taking tamoxifen if I have pulmonary hypertension?

I will be having a tamoxifen challenge on Monday with the goal of starting it again (redness reaction on my chin with warmth/burning sensation that stopped with temporary discontinuation of the medication - allergy needs to be confirmed or invalidated). However, between the time the appointment was made and today, I have learned that my valve disease has progressed (medium regurgitation with mild high pulmonary pressure). I just realized that there may be a contraindication to taking tamoxifen (FYI: since the pulmonary pressure is mild, I am not currently taking any medication for this condition).