Fractional Flow in Cerebrovascular Disorders.

There is an urgent need for stroke experts to advance the care of their patients, yet current approaches are outmoded and have not been successful. The traditional emphasis on anatomical identification of disease, using percent luminal stenosis, results in suboptimal identification of lesions likely to produce recurrent ischemia and, consequently, results in poor patient selection and hampers the development of new aggressive treatments. The traditional emphasis on time since symptom onset and alleged need to achieve complete revascularization in patients with acute ischemic stroke ignores the very nature and degree of the underlying culprit lesion and hampers our understanding of the relationships between the patient's original ischemic state, revascularization, reperfusion, reperfusion injury and hemorrhagic transformation. The trajectory for the study and care of cerebrovascular patients needs to adapt, as it has in cardiology, employing hemodynamics and pathophysiology as the new guideposts for advancement. We introduce fractional flow as one hemodynamic parameter to be utilized to set a course on this new path for the care of stroke patients.