They kept me in the hospital for an extra day to get my INR into the recommended range. The surgeon doing rounds told me I would go home, but the surgeon who did the work later decided he wanted me to stay an extra day. I still was released with my INR being a few points from optimum, but for my St. Jude valve, being on the low side is not a problem. It took about 4 weeks before my INR hit the "right" range. My cardiologist said because of my valve type that it was not a problem.