Percutaneous Closure of Patent Foramen Ovale Is the Procedure of Choice for Paradoxical Embolism
To the Editor:
Meier and Lock1 presented convincing evidence for the rationale for closure of patent foramen ovale (PFO) in stroke patients. Paradoxical embolism as a cause of stroke was first diagnosed by cardiac catheterization over a quarter of a century ago.2 With the advent of contrast echocardiography combined with the use of a Valsalva maneuver,3 the diagnosis can now be made noninvasively.
Since the original report by Lechat et al in 19884 of a significantly higher prevalence of PFO in patients with ischemic stroke younger than 55 years of age, ample supportive studies have been published, including a recent meta-analysis of case-control studies.5 There should be no longer any question that percutaneous closure is preferable to surgical closure.1
In a recent visit to Dr Meier’s laboratory, I witnessed a succession of such procedures accomplished successfully in one afternoon without the use of transesophageal echocardiography, thus greatly shortening the procedure time to <30 minutes. I also saw a patient with acute myocardial infarction and normal coronary arteriograms who turned out to have a PFO with presumed coronary embolism. In that regard, I pointed out in 1976 that paradoxical embolism may be responsible for myocardial infarction in patients with normal coronary arteriograms.2 Therefore, paradoxical embolism should always be included in the differential diagnosis of myocardial infarction with normal coronary arteriograms as well as in patients with stroke who are middle aged or younger.
Meier B, Lock JE. Contemporary management of patent foramen ovale. Circulation. 2003; 107: 5–9.
Cheng TO. Paradoxical embolism: a diagnostic challenge and its diagnosis during life. Circulation. 1976; 53: 565–568.
Overell JR, Bone I, Lees KR. Interatrial septal abnormalities and stroke: a meta-analysis of case-control studies. Neurology. 2000; 55: 1172–1179.
Dr Cheng was the first to emphasize the importance of paradoxical embolism.1 This happened simultaneously with the first description of percutaneous closure of atrial septal defects.2 Dr Cheng also described the combination of a Valsalva maneuver with echocardiography.3 Little did he know that a quarter of a century later, the clinical entity (paradoxical embolism) and the diagnostic technique (echocardiography combined with Valsalva) described by him would emerge as a routine unit together with percutaneous closure of a special form of an atrial septal defect—the patent foramen ovale.
We hereby acknowledge these prophetic contributions of a fine clinical and medical historian and fully support his reminder that paradoxical embolism is by no means confined to the brain.