Novel Scoring System to Identify Which Patients Benefit From PFO Device Closure

While PFO device closure decreases stroke recurrence risk overall, the best treatment for any individual is often unclear. Therefore, Dr David M. Kent and his team conducted a study to evaluate heterogeneity of treatment effect of PFO closure on stroke recurrence based on previously developed scoring systems.

The researchers pooled individual patient data from the Systematic, Collaborative, PFO Closure Evaluation (SCOPE) consortium, which analyzed 3,740 patients data from six randomized trials comparing PFO closure plus medical therapy to medical therapy alone for recurrent stroke prevention.

The researchers compared the effect of PFO closure plus medical therapy and medical therapy alone. In subgroup analyses, they used the Risk of Paradoxical Embolism (RoPE) Score (a 10-point scoring system in which higher scores reflect younger age and the absence of vascular risk factors) and the PFO-Associated Stroke Causal Likelihood (PASCAL) Classification System, which combines the RoPE Score with high-risk PFO features (either an atrial septal aneurysm or a large-sized shunt) to classify patients into 3 categories of causal relatedness: unlikely, possible, and probable. The major outcome assessed was the incidence of ischemic stroke.

Key findings of the study:

• At 57 months, the researchers found that the annualized incidence of stroke was 1.09% in those assigned medical therapy alone and 0.47% in those assigned PFO closure plus medical therapy (adjusted HR = 0.41).
• In subgroup analyses, they observed statistically significant interaction effects.
• They found that patients with low RoPE scores had a higher risk for stroke (HR = 0.61) than those with high RoPE scores (HR = 0.21).
• In patients who were classified as unlikely, possible, and probable using the PASCAL Classification System, they observed that the HRs was 1.14, 0.38, and 0.10, respectively.
• They noted that the 2-year absolute risk reduction for stroke due to PFO closure was 2.1% in both the possible and probable groups, but –0.7% in the unlikely group.
• They also found that the adverse events of device closure, such as atrial fibrillation, appear to be concentrated in those patients who fall into the unlikely classification, who appear to get no benefit.

The authors concluded, "Among patients aged 18 to 60 years with PFO-associated stroke, risk reduction for recurrent stroke with device closure varied across groups classified by their probabilities that the stroke was causally related to the PFO. Application of this classification system has the potential to guide individualized decision-making."

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DOI: 10.1001/jama.2021.20956