GENERAL NEUROLOGY
PASCAL classification
(PFO-Associated Stroke Causal Likelihood)
Updated on 15/10/2024, published on 09/10/2024
- the prevalence of the patent foramen ovale (PFO) in the general population is ~ 25%
- the discovery of a PFO in a stroke patient is not synonymous with a diagnosis of paradoxical embolism
- the 10-point Risk of Paradoxical Embolism (RoPE) score has been proposed to help establish the relationship between cryptogenic stroke and PFO; it is based on age and vascular risk factors and ignores anatomic and physiologic characteristics of the PFO
- The PASCAL (PFO-Associated Stroke Causal Likelihood) classification system combines the RoPE score with PFO characteristics (Kent, 2023):
- features that increase the likelihood of PFO-stroke mechanisms: high-risk PFO physiologic and structural features of a large shunt or atrial septal aneurysm
- features that increase the likelihood of an occult non-PFO stroke mechanism: older age, vascular risk factors as quantified in the RoPE score
- based on a combination of these factors, the PASCAL Classification assigns a likelihood of causality to one of five levels: definite, highly probable, probable, possible, and unlikely
- this classification improves clinical decision-making, particularly regarding PFO closure in cryptogenic stroke patients
Risk Grade | Features | Causal Relatedness | |
Low RoPE Score | High RoPE Score (> 7) | ||
very high risk | PFO + straddling thrombus | definitive | definitive |
high risk | PFO + ASA or large shunt PFO AND PE or DVT preceding index infarct |
probable | highly probable |
medium risk | PFO + ASA AND/OR Large shunt PFO |
possible | probable |
low risk | small shunt PFO without ASA | unlikely | probable |
- a higher RoPE score (> 7 points) increases the probability of a causal association between PFO and stroke
- ASA – atrial septal aneurysm
- the shunt is assessed either by TEE or, even better, by the TCCD bubble test