It must be determined by the Cleveland Clinic, that your wife's lung and heart are as good as they can be. Then it must be determined that she is no longer having blood clots in the lung. If these conditions are met, she should then start a long-term physical conditioning program. This should include both pulmonary and cardiac rehabilitation. If all of the blood clots are now firmly fixed in the blood vessels of her lungs, it is likely that she will need to continue using oxygen. Her blood oxygen level should be checked in all circumstances, including at rest, standing, lying down, awake, asleep, and with activity.