CARDIOVASCULAR JOURNAL OF AFRICA • Volume 34, No 1, January–April 2023 AFRICA 37 atrial septal aneurysm (ASA)] and presence of a Eustachian valve/Chiari network in the right atrium. In certain rare instances when TOE is contra-indicated, or a patient cannot tolerate an invasive procedure, additional imaging modalities of cardiac magnetic resonance (CMR) or cardiac computed tomography (CT) are potential diagnostic tools. Studies looking at dynamic sequences using dedicated protocols may accurately diagnose PFO and ASA with or without significant shunting. Cardiac CT may be considered in cases where detailed definition of the PFO/ASA anatomy may impact on management. Cardiac CT and CMR have the advantage that they can contemporaneously detect alternative aetiologies for a stroke (atherosclerotic plaques in the aorta, large-vessel dissections, intracardiac thrombus, left ventricular non-compaction).12,13 However, these imaging modalities are limited by accessibility and limited expertise in interpretation and reporting in the South African context. Evidence supporting closure Six major trials (see Table 3) have evaluated PFO closure over medical management alone in preventing cryptogenic stroke recurrence. On average, the risk of a recurrent stroke was reduced from 5–2% over a three- to six-year period in patients who underwent PFO closure compared to medical therapy.14,15 Based on this research evidence, PFO closure is indicated for most patients (particularly in the group younger than 65 years of age) with cryptogenic stroke in whom the cause is thought to be PFO. Patients with a suspected PFO-related stroke who have a recurrent event despite medical therapy should also be offered PFO closure. There is little evidence for PFO closure in other clinical settings, but PFO closure may be indicated in rare circumstances for very specific clinical scenarios: • professional divers and unexplained decompression sickness • arterial deoxygenation syndromes.16 PFO closure is not indicated for the treatment of migraine outside the setting of a clinical trial. Complications of PFO closure Percutaneous PFO closure is a highly successful procedure. Effective closure rates were 93.5% in the RESPECT and 94.5% in REDUCE trials. Procedural complications of percutaneous PFO closure are rare. Atrial perforation, device embolisation and bleeding from inadvertent arterial puncture need to be avoided by careful procedural technique and preferably ultrasound-guided vascular access. Long-term complications include potential thrombus formation on the device, aortic root dilatation with subsequent device erosion and an increased risk of new-onset AF (approximately 5% of patients develop AF after PFO closure).17,18 AF episodes usually occur early (85% within 45 days in the REDUCE trial) and are not prolonged (60% within two weeks in the REDUCE study). For this reason, some suggest oral anticoagulation for three months post PFO closure to avoid AF-related stroke. Postprocedural follow up and antithrombotic therapy It is recommended that patients receive aspirin 75 mg daily and clopidogrel 75 mg daily for three months after the procedure and continue with aspirin 75 mg daily lifelong thereafter.19 A TTE should be performed prior to discharge to confirm correct positioning of the device and rule out any early complications. Further follow up, including repeat TTE, is recommended one and six months after the procedure to confirm successful closure and detect delayed complications. Data on the impact of residual shunts at follow up on post-closure stroke risk are unclear and no clear management recommendations can be made. Long-term follow-up studies of patients with mild shunts are reassuring.20-22 The optimal management of patients with large residual shunts is not clearly established and includes conservative management with careful follow up, long-term management with antithrombotic and/or Table 3. Six major trials evaluated PFO closure over medical management alone Study acronym Study title Device employed Sample size Follow up (months) Intervention vs control Study outcome CLOSURE I29 Evaluation of the STARFlex septal closure system in patients with a stroke and/or transient ischaemic attack due to presumed paradoxical embolism through a patent foramen ovale STARflex septal closure system 909 N/A PFO closure with aspirin and clopidogrel vs aspirin or warfarin or both No difference with regard to recurrent stroke/TIA PC30 Percutaneous closure of patent foramen ovale in cryptogenic embolism Amplatzer PFO occluder 414 49 (mean) PFO closure with aspirin and clopidogrel/ticlopidine vs antiplatelet and/or warfarin No difference with regard to recurrent embolic events RESPECT31 Randomised evaluation of recurrent stroke comparing PFO closure to established current standard-of-care treatment Amplatzer PFO occluder 980 31 (median) PFO closure with aspirin and clopidogrel vs aspirin or warfarin or aspirin and dipyridamole or clopidogrel No difference with regard to recurrent stroke CLOSE32 Patent foramen ovale closure or anticoagulants versus antiplatelet therapy to prevent stroke recurrence Various 663 53 (mean) PFO closure with aspirin and clopidogrel vs aspirin or clopidogrel or aspirin and dipyridamole Reduced risk of recurrent stroke in the closure group DEFENSE-PFO33 Device closure versus medical therapy for cryptogenic stroke patients with high-risk patent foramen ovale Amplatzer PFO occluder 60 24 (median) PFO closure vs dual antiplatelet therapy and/or warfarin Reduced risk of recurrent stroke in the closure group REDUCE34 Gore septal occluder device for patent foramen ovale closure in stroke patients Helex septal occluder or Cardioform septal occluder Gore 664 38 (median) PFO closure with aspirin or aspirin and dipyridamole or clopidogrel vs aspirin or aspirin and dipyridamole or clopidogrel Reduced risk of recurrent stroke in the closure group
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