Discussion
While the role of PFO in refractory hypoxemia and cryptogenic stroke in patients with COVID-19 may have often been overlooked throughout the pandemic, there is currently no evidence-based recommendation regarding the management of these patients.1, 3-5, 13 To our knowledge, this report highlights the first case of PFO closure in a COVID-19 patient using NobleStitch.
While COVID-19 can often present with thromboinflammation and a hypercoagulable state, right-to-left shunting through a PFO further increases the risk for paradoxical embolism, possibly due to the increased right atrial pressure.3, 5, 14 This is a predicament in patients with a PFO in the setting of COVID-19 pneumonia, where increased right-sided pressures induce vascular damage, further activating the coagulation system and exacerbating the risk for paradoxical embolism.1, 4, 5 Moreover, the increased pulmonary pressures in these patients may be responsible for the refractory hypoxemia that is seen.3, 4 Surgical correction may not only improve oxygenation and right-to-left shunting in these patients, but it can also help prevent cryptogenic strokes.1, 4, 13
The NobleStitch provides a novel way of closing a PFO which represents a significant source of embolic stroke and refractory hypoxemia.8 Guided by transesophageal echocardiography (Video 1), this technique effectively closes the PFO by applying sutures through the septum primum and septum secundum, subsequently creating a knot between the two sutures and removing excess suture material, thereby avoiding many risks that accompany septal occluders.8 Hypercoagulable patients such as those with COVID-19 may be at increased risk of thrombotic complications with permanent implants with a large device burden. Additionally, these permanent devices can eventually hinder left-sided heart procedures in younger patients who might benefit from such interventions later on in the future.9
Thus far, NobleStitch has shown promising results in terms of effectiveness, safety, and longevity.9, 10, 15 To improve patient selectivity, a retrospective observational study of 247 patients who underwent PFO closure with NobleStitch suggested new predictors of residual shunting after intervention. This study revealed improved outcomes with a preoperative PFO < 5mm in width and absence of a spontaneous right to left shunt, indicators that were both met in our patient.10 Another prospective single-center study with a six month follow up period (n=116) investigated factors that may have contributed to residual intracardiac shunting \(\geq 2\ (20\%,\ n=23),\ \)revealing partial stitch detachment (n=12), atrial septal tear (n=3), and KwiKnot embolization (n=2) as the main causes of right-to-left shunting at follow up.11 Although NobleStitch is not without complications, it has clear advantages over commonly used device PFO closures.8, 9, 11
This case highlights how the NobleStitch procedure may be used to close a PFO in a COVID-19 patient on VV-ECMO with refractory hypoxemia and cryptogenic stroke. Particularly useful in younger patients, this deviceless system overcomes many of the complications associated with traditional PFO closure devices.8 Given the ubiquity of COVID-19 and its complications, early detection and treatment of PFO in patients with severe COVID-19 are critical for timely recovery and prevention of serious sequelae.4 Furthermore, given the hypercoagulable state with severe COVID-19, choosing a deviceless method to close the PFO may avert clot formation, future strokes, and the need for anticoagulation. This case highlights that the NobleStitch device shows promise in avoiding severe neurologic sequelae of cryptogenic stroke. Notably, PFO closure with NobleStitch is a relatively noninvasive cardiac intervention with a low device burden, allowing for future surgical intervention, especially in younger patients.