Thrombus formation during percutaneous closure of an atrial septal defect with an Amplatzer septal occluder

Percutaneous closure of an ostium secundum-type atrial septal defect is typically a safe and effective therapeutic option in the presence of significant shunting or paradoxical embolism. Infrequently, however, periprocedural sequelae occur.Herein, we report the cases of 2 patients, each of whom underwent transcatheter closure of an atrial septal defect with the use of an Amplatzer Septal Occluder under transesophageal echocardiographic guidance. In both patients, acute thrombi formed periprocedurally, despite preprocedural anticoagulation. In patient 1, the infusion of unfractionated heparin for 24 hours prevented the recurrence of thrombus; in patient 2, the thrombus was isolated under the arm of the occluder, and unfractionated heparin was infused. Both patients were asymptomatic and without detectable thrombus after the procedure and at follow-up. These reports highlight a rare early sequela and the importance of transesophageal echocardiographic monitoring during the percutaneous closure of an atrial septal defect.

The discovery of aspirin's antithrombotic effects

Aspirin has long been established as a useful analgesic and antipyretic. Even in ancient times, salicylate-containing plants such as the willow were commonly used to relieve pain and fever. In the 20th century, scientists discovered many details of aspirin's anti-inflammatory and analgesic properties, including its molecular mechanism of action. In addition, the latter half of the century brought reports that daily, low doses of aspirin could prevent myocardial infarction and stroke. This finding was first reported by Lawrence Craven, a suburban general practitioner in Glendale, California. Unfortunately, Craven's work went largely unnoticed, and decades passed before his observations were verified by clinical trial. We present Craven's story, which demonstrates the value of a single physician's commitment to lifelong learning. In addition, we summarize the work of the physicians and scientists who discovered the molecular mechanisms by which aspirin exerts its antiplatelet effects. Collectively, these discoveries exemplify the complementary roles of basic science and clinical observation in advancing medicine.

Pulmonary microthrombi during left ventricular assist device implantation

Critically ill heart failure patients undergoing left ventricular assist device implantation have alterations in their coagulation profiles; as a result, hemorrhagic complications during the postoperative period are the most common and serious problems during device support of these patients. The use of aprotinin therapy is generally accepted for reducing bleeding after coronary artery bypass grafting procedures, heart transplantation, and insertion of a left ventricular assist device. We describe the case of a patient who had a suprasystemic increase in pulmonary artery pressure, caused by thromboembolic occlusion of the pulmonary arterioles after urgent implantation of a left ventricular assist device. The complications developed after the patient was weaned from cardiopulmonary bypass and heparinization was reversed with protamine. Although the thrombosis was successfully reversed with intraoperative administration of tissue plasminogen activator directly to the pulmonary artery, the patient died of massive hemorrhage 6 hours later. To our knowledge, the direct application of tissue plasminogen activator into the pulmonary artery in such a catastrophic situation has not been used elsewhere.