I have edited the following as I missed something No. It will add to it. Natto is one of the prime sources of all the menaquinones(sp.)or K2. Supplementing with the MK7 form of K2 will just add to the effect of normalizing the INR readings if you are forced to do that. Nattokinase is an extract of Natto and I am not sure it has any K2, nor do I know if nattokinase has any blood thinning properties. Natural blood thinners are green tea, garlic, fish oils among others. K1, prevents you from bleeding to death by allowing your blood to clot at wounds.
If your blood is too thick or clotting abnormally, it is not because of too much k1 or k2, but inflammation. A proper balance in your digestion and food intake, minimizing processed foods and additives, cutting back on added sugars and synthetics, poisons like aspertame, sucralose, pesticides, chlorine, chloramins, bromines, fluoride, mercury, lead, and supplementing when you are deficient (D3, mag, k2, iodine, omega 3's are the main deficiencies in most Americans) should take care of you. I would add to stay away from doctors, drugs and hospitals, esp flu shots.