IJCS | Volume 33, Nº4, July and August 2020

DOI: https://doi.org/10.36660/ijcs.20200128 A matter of intense debate in the last decades, the ideal strategy for secondary prevention in patients with cryptogenic stroke and patent foramen ovale (PFO) is not yet clearly defined. PFOs are prevalent in the general population and can be found in up to 40% of patients with cryptogenic stroke. 1 Although in some cases of cryptogenic stroke PFO might be just an innocent bystander, paradoxical embolism is a well- known potential causative mechanism, especially in patients with concomitant deep venous thrombosis, whereby PFO closure may represent an effective measure to avoid recurrences. 2 Even among patients with PFO, phenotypical heterogeneity may also determine percutaneous treatment suitability and directly impact on results, whereas the presence of large shunts, atrial septal aneurysm or associated complex septal defects must also be taken into account. In the past years, several evidence-based guidelines and expert consensus on the management of patients with PFO and prevention of recurrent stroke have been published by international scientific societies, including a position paper sponsored by the EuropeanAssociation of Percutaneous Cardiovascular Interventions (EAPCI), with the participation of eight European scientific societies. 3 A recent guideline by the American Academy of Neurology (AAN) was published online last April. 4 This issue of the International Journal of Cardiovascular Sciences presents the results of an interesting study entitled “The Role of Patent Foramen Ovale Closure in the Secondary Prevention of Cryptogenic Stroke: a Meta-Analysis Report”, authored by Pereira and coworkers. 5 This study sheds new light on the discussion of this important topic, adding relevant information about the results of different management strategies for secondary prevention of stroke in patients with PFO. The authors included data from six randomized clinical trials with a total of 3,750 patients. Unlike other meta-analyses published so far, they considered only original clinical trial data, a difference that provides more reliability to the obtained results. Interestingly, there was a significant lower incidence of stroke in patients submitted to PFO closure compared with those who received medical treatment alone (risk ratio [RR] = 0.37; 95% confidence interval [0.17 to 0.78]; p = 0.01), in accordance with recent findings of the CLOSE and DEFENSE-PFO trials, 6,7 which recruited only PFO patients with high-risk anatomic features. It is important to emphasize that ischemic stroke may be caused by a variety of heterogeneous mechanisms, and adequate secondary prevention must focus on the correct target population. Not every PFO is deemed for closure and not every PFO anatomy is amenable to percutaneous closure, but once the procedure is correctly indicated, it is of paramount importance to assemble a multidisciplinary team in charge of choosing the correct device and minimizing complications. 8 Diagnosing PFO is not always a simple matter. Many factors can contribute for a non-diagnostic study and yield false positive results, such as intrapulmonary shunts or false negative diagnoses due to an inadequate Valsalva maneuver or a redundant Eustachian valve, which may prevent the contrast solution from reaching the atrial septum. Therefore, in order to achieve the best results, it is crucial to follow a stepwise approach with transthoracic echo (TTE), transcranial Doppler (TCD) 318 EDITORIAL International Journal of Cardiovascular Sciences. 2020; 33(4):318-320 Mailing Address: Alex Felix Rua das Laranjeiras, 374. Postal Code: 22240-006, Rio de Janeiro, RJ – Brazil E-mail: alexsfelix@gmail.com To Close or not to Close PFOs in Cryptogenic Stroke, an Evolving Question Alex Felix 1,2, 4 a nd Monica Luiza de Alcantara 2, 3 Instituto Nacional de Cardiologia, 1 Rio de Janeiro, RJ – Brazil Americas Medical City, 2 Rio de Janeiro, RJ – Brazil Rede D'Or São Luiz, 3 Rio de Janeiro, RJ – Brazil Diagnósticos da América, Rio de Janeiro, RJ - Brazil Editorial related to the article: The Role of Patent Foramen Ovale Closure in the Secondary Prevention of Cryptogenic Patent Foramen Ovale; Secondary Prevention; Stroke/ prevention and control; Risk Factors; Atrial Fibrillation. Keywords