Pulmonary Infarction: In the Beginning: The Natural History of Pulmonary Infarction.

Background: Massive pulmonary emboli can cause an abrupt onset of symptoms simultaneous with large pulmonary artery occlusions. In contrast, the temporal relationship between pulmonary vascular occlusion by smaller emboli and the development of symptoms of pulmonary infarction is unknown. We describe the time interval between embolization and the onset of clinical symptoms and signs compatible with pulmonary infarction.

Methods: We examined the records of 56 patients with hereditary hemorrhagic telangiectasia (HHT) who underwent therapeutic balloon embolization of pulmonary arteriovenous malformation (PAVM) in a single center after noting that some of them experienced symptoms and signs compatible with pulmonary infarction. Because both the times of embolization and the onset of clinical symptoms were documented in medical records, we were able to calculate the time interval between embolic occlusion of vessels and the onset of symptoms.

Results: The records of 56 patients who underwent therapeutic embolization for HHT were examined. Five patients experienced a single episode of pleuritic pain postembolization, and one patient experienced episodes of pleuritic pain after each of two separate embolization procedures. Four of these pleuritic pain events evolved into a complex compatible with pulmonary infarction. The time intervals between embolization and the onset of pleuritic pain in those experiencing the infarction symptoms and signs were 24 hours, 48 ± 4 hours, 65 hours, and 67 hours, respectively.

Conclusions: The clinically silent time interval between embolization of a pulmonary artery and the onset of symptoms and signs compatible with lung infarction is 24 hours or greater.