By Michael Crawford, MD
Professor of Medicine, Chief of Clinical Cardiology, University of California, San Francisco
Dr. Crawford reports no financial relationships relevant to this field of study.
SYNOPSIS: In the modern era, cardiac tamponade is most commonly caused by malignancies with poor prognosis. As compared to older literature, iatrogenic causes have increased, most resulting from complications of percutaneous coronary intervention.
SOURCE: Sánchez-Enrique C, et al. Cause and long-term outcome of cardiac tamponade. Am J Cardiol 2016;117:664-669.
Little is known about the etiologies and prognosis of cardiac tamponade in the modern era. Thus, investigators from Madrid performed a retrospective observational study from 2003 to 2013 on 136 consecutive cases of cardiac tamponade. Patients with large pericardial effusions but no clinical signs of pericardial tamponade were not included. Pericardial fluid was evaluated. An exudative effusion was defined as a pericardial fluid protein to serum protein ratio of > 0.5, or was highly cellular, or had a glucose < 60 mg/dL. The patients were classified into seven groups: infective, neoplastic, uremic, iatrogenic, myocardial infarction (MI), other causes, and idiopathic. Researchers followed all patients for at least 1 year. The median age was 65 years, and 55% were men. Pericardiocentesis was required in 81%. Most had a transudate or hemorrhagic fluid. A positive cytology occurred in 15% and bacteria in 4%. Malignancy was the most common cause (32%), followed by infection (24%), idiopathic (16%), iatrogenic (15%), post-MI (7%), uremic (4%), and other (2%). The most common malignancies were lung (55%) and breast (18%). In the iatrogenic group, percutaneous coronary interventions (PCI) were the most common. Cardiac tamponade recurred in 10%, and 48% died. Malignancy carried the highest probability of both events (hazard ratio, 5.47; 95% confidence interval, 3.27-9.61; P < 0.001). The authors concluded the most common cause of cardiac tamponade is malignancy, and it has the worst prognosis. With aggressive management, other causes have a much better prognosis, especially iatrogenic causes.
Pericardial tamponade is infrequent, and much of our knowledge about its causes and prognosis is based on older literature. Thus, this contemporary 10-year experience in a modern urban hospital is of interest. Older literature suggested idiopathic was the most common diagnostic category, but now one-third of cases are due to malignancy. There are several possible reasons for this. Physicians may be better at diagnosing malignant effusions. Before, performing cytology on pericardial fluid was worthless; however, in this series it was positive in 46% of proven malignancy cases. Infection was common, whereas physicians once considered infective cardiac tamponade unusual. Surely the use of polymerase chain reaction and perhaps better culture techniques have increased the ability to diagnose infected fluid.
However, the infective causes have changed. Tuberculosis is much less common, although not gone, and the viral causes are now likely to be cytomegalovirus and herpes, rather than coxsackie and echovirus. Although not in this series, other contemporary populations would have more HIV. Iatrogenic causes would have been unusual in the last century, but now share third place with idiopathic.
Interestingly, most of the iatrogenic cases were post-PCI, probably because more stents are deployed now than 10 years ago. Post-MI was next most frequent and it was most commonly free wall rupture. That seems unique to this series, as hospitals with ST elevation MI PCI teams on call rarely experience cardiac rupture. Finally, there were no cases of rheumatic diseases causing tamponade, which may be due to modern therapy with biologic agents.