Figure 1.

PFO Propensity and the Probability that a Stroke is PFO-attributable. We define PFO propensity as the probability of finding a PFO in a patient, based on patient-specific characteristics (such as age and the presence or absence of hypertension, diabetes and hypercholesterolemia). Through Bayes' theorem, it is directly (though non-linearly) related to the probability that a cryptogenic stroke is PFO-attributable (in patients with both cryptogenic stroke and PFO).