Right-to-left shunt and the hypercoagulable state: does paradoxical embolism play a role in patients with antiphospholipid syndrome and stroke?

Antiphospholipid syndrome leading to paradoxical embolus and stroke via secundum atrial septal defect

We have presented a case of a 22-year-old man, presenting with cerebral infarct, subsequently found to have antiphospholipid syndrome (APS), deep venous thrombosis, pulmonary embolism and atrial septal defect (ASD), thereby confirming the presence of infarct due to paradoxical embolism in this patient. The importance of ASD in the patients of APS, resulting in paradoxical embolism is debatable, with recent studies undermining its importance. We have demonstrated that it does indeed happen. This would have implications in the risk assessment and management of ASD in such patients. This case report is intended to serve as a reminder of this association and the need to perform further research in this area.

Transcranial Doppler findings in antiphospholipid syndrome

INTRODUCTION

Transcranial Doppler is a method that enables the assessment of different cerebral hemodynamic parameters. It also allows for the evaluation of the presence of right-to-left circulation shunts (RLS) and for the detection of microembolic signals (MESs), which might be associated with an increased risk of cerebrovascular events. For instance, the presence of MESs on transcranial Doppler in patients with systemic lupus erythematous (SLE) and antiphospholipid syndrome (APS) is associated with an increased risk of stroke. Therefore, transcranial Doppler could be a useful tool for stroke risk stratification in these patients.

OBJECTIVE

Our objective was to evaluate transcranial Doppler cerebral mean blood flow velocities as well as the presence of MESs and RLS in patients with antiphospholipid syndrome and SLE.

PATIENTS AND METHODS

Twenty-two patients with primary APS (PAPS), 24 patients with secondary APS (SAPS), 27 patients with SLE without APS and 21 healthy controls were evaluated. Clinical and epidemiological data were compiled from medical charts, and all subjects underwent transcranial Doppler examination with breath-holding index calculation. Both middle cerebral arteries were monitored for 60 min for the detection of MESs. RLS was investigated with agitated saline injected as a bolus.

RESULTS

There were no significant differences in mean blood flow velocities among the groups. MESs were more frequently found in patients with SLE when compared with controls and patients with APS (SLE: 17.4%, SAPS: 4.3%, PAPS: 0%, controls: 0%, p = 0.03). Anticoagulant therapy was more frequently used in the APS group (PAPS: 81.8%, SAPS: 75.2%, SLE: 1.7%, p < 0.001). Patients with APS had a higher frequency of RLS when compared with volunteers (63.6% versus 38.1%, p = 0.05). Breath-holding index values tended to be lower in patients with SAPS than in control subjects and patients with PAPS and SLE ( p = 0.06).

CONCLUSIONS

Patients with APS had a higher frequency of RLS than healthy controls. This finding alerts to the importance of cardiac investigation in patients with stroke and APS, because further therapies such as RLS occlusion might eventually add protection. The higher frequency of MES in patients with SLE could suggest an effect of anticoagulant therapy on MES prevention, more frequently used in patients with APS.

Clinical and infarction patterns of PFO-related cryptogenic strokes and a prediction model

Objectives

The higher than expected PFO rate in CS patients has raised concerns that paradoxical embolism maybe the pathophysiologic mechanism for strokes. However, only a small proportion of pathogenic PFOs cause CS. Therefore, accurate recognition of patients with pathogenic PFOs among all CS patients could guide clinical decision making in selecting the most appropriate treatment. The aim of this study was to devise a new algorithm to stratify cryptogenic stroke (CS) patients into pathogenic patent foramen ovale (p‐PFO)‐ and non‐p‐PFO‐related patients.

Methods

A total of 1201 patients with acute ischemic stroke were recruited from two different medical centers, and 253 CS patients were identified. Of the 253 patients, 111 were diagnosed with PFO using contrast transcranial Doppler. Data on medical histories, neuroimaging and laboratory tests were compared in CS patients with or without PFO.

Results

Compared with PFO‐negative CS patients, PFO‐positive CS patients showed younger onset age, lower incidence of hypertension and dyslipidemia, characteristic infarction pattern in magnetic resonance imaging and specifically altered platelet activity and coagulation function. Based on the above information, we constructed a PFO judgment formula (Hr‐PFOJ) by means of feature weight estimation and predictive performance evaluation to predict pathogenic PFO in CS patients with a sensitivity of 76.3% and a specificity of 66.5%.

Interpretations

Hr‐PFOJ judgment formula is a useful screening tool for identification of patients with pathogenic PFO who may benefit from PFO‐related treatment.