Nicotine replacement products have not been shown to increase blood pressure. So far, only one clinical trial has measured blood pressure after e-cigarette use, and no increase in heart rate or blood pressure was seen.
http://www.casaa.org/files/Virgiania Commonwealth University Study.pdf
For that matter, smoking doesn't seeme to be a direct cause of hypertension, either. In fact, in at least two life-style intervention trials, the groups that succeeded in stopping smoking had a higher rate of hypertension develop than those who kept smoking.
As far as blood clots go, I have heard that smoking increases the risk of blood clots, but so far have never seen any reports that straight nicotine does so.
As anecdotal evidence, I offer this. I have been on HRT for over 10 years. As you may have read, HRT increases the risks of the type of strokes caused by blood clots (from 2 out of 10,000 to 4 out of 10,000). My blood used to clot very rapidly when I was smoking. Now that I am vaping, my blood clots very slowly. I have to apply pressure to get the bleeding to stop when I cut myself.
At the age of 22, the risk of blood clots are very low unless you have a genetic risk factor.
According to the CDC "Summary Chart of U.S. Medical Eligibility Criteria for Contraceptive Use, 2010," even among women who smoke, if the age is less than 35, the advantages for using contraceptives outweigh the risks.
Summary Chart of US Medical Eligibility Criteria for ... Age. Menarche to <40=1. Menarche to <18=1. ... (DVT) /Pulmonary. i) higher risk for recurrent DVT/PE, 4, 2, 2, 2, 2, 1. embolism (PE). ...
www.cdc.gov/reproductivehealth/UnintendedPregnancy/Docs/USMEC-Color-final.doc