Commentary: Your eyes can deceive you; don't trust them.

Hans Chiari in 1897. First description of a Chiari network.

Chiari network leading to a stroke treated with a minimally invasive approach is discussed.

See Article page 45.

The Chiari network, found infrequently in the right atrium, is a fenestrated, net-like embryonic remnant from failure of resorption of the right-sided sinus venosus valve. Developmentally, the right valve of the sinus venosus evolves into 2 valves: the valve of the inferior vena cava (Eustachian valve) and the valve of the coronary sinus (Thebesian valve). Hans Chiari, an Austrian pathologist, first described this phenomenon in 13 human right atria in 1897, and the prevalence has been reported to be 2% to 14%. Usually it has no significance, but in some cases, it can lead to diagnostic confusion, causing thromboembolism, endocarditis, arrhythmias, and so on.

In the current issue of this Journal, Manerikar and colleagues report a unique case of a patient presenting with Chiari network and a patent foramen ovale (PFO) who suffered a stroke and was treated surgically using a minimally invasive approach. Another conundrum in this case was the suspicion of a left heart mass that clouded the picture of what caused the stroke and how best to treat it.

The authors are to be commended on their clinical reasoning and problem-solving, but although undoubtedly novel and unique in its presentation, we must be careful not to apply too broadly the conclusions from this case report. First, the Chiari network is a relatively common benign clinical finding and may be associated with a PFO in the general population. If the authors had not found the left-sided mass, their urgency to proceed with surgical intervention would perhaps been different and perhaps a percutaneous option would have been considered. The choice of the surgical approach via right thoracotomy is logical, as it affords appropriate visualization to both the right and left atrium, avoiding manipulation of the heart before crossclamping. Nonetheless, their approach in this clinically unique patient can certainly not be generalized, and perhaps other methods of treatment can be argued, namely, improved cross-sectional imaging to study the left-sided mass, the use of anticoagulation, and defining the landmarks of the PFO to consider a percutaneous approach. All of these are considerations for this rare presentation, each with its limitations. However, what we learn from this case is, even apparent benign conditions should be thoroughly studied and surgical interventions with less morbidity and quicker recovery can be undertaken to achieve an adequate result.