VENOUS THROMBOSIS CAUSING ARTERIAL EMBOLIZATION TO THE SAME LIMB THROUGH A PATENT FORAMEN OVALE

We describe a patient who presented with acute ischemia affecting the left lower limb. Because a transthoracic echocardiogram was abnormal, a transesophageal study was arranged. This demonstrated an atrial sept al aneurysm and right-to-left shunting of contrast, raising the possib ility of paradoxical embolism. The diagnosis was confirmed by contrast venography, which showed extensive thrombosis in the deep veins of th e left thigh, and a ventilation-perfusion scan which was consistent wi th multiple pulmonary emboli. Among the lessons from this case was the finding that in patients with arterial embolism the likely origin of the embolus should be considered and, in the absence of common risk fa ctors (atrial fibrillation, rheumatic heart disease, left ventricular dilatation, widespread atheroma), occult venous thrombosis and a right -to-left shunt should be sought. In this select group of patients, tra nsesophageal echocardiography is significantly more sensitive than tra nsthoracic study and should be the investigation of choice. Second, in the patient described in this report the clinical signs of deep venou s thrombosis (DVT) were masked by the more prominent features of acute arterial ischemia. Without the incidental echocardiographic abnormali ty, it is likely that the important diagnoses of DVT, pulmonary emboli sm, and paradoxical embolism would not have been made.