What are the risks of transcatheter aortic valve implantation (TAVI) in patients with antiphospholipid syndrome and how should peri‑procedural anticoagulation be managed?

Risk of TAVI in Antiphospholipid Syndrome

Patients with antiphospholipid syndrome (APS) undergoing TAVI face substantially elevated perioperative thromboembolism risk, with case series demonstrating cerebrovascular events in 67% of APS patients, necessitating aggressive anticoagulation strategies that must be carefully balanced against bleeding complications. 1

Evidence of Thrombotic Risk in APS Patients

The only published case series specifically examining TAVI in APS patients reported three cases, where two patients (67%) developed cerebrovascular events perioperatively despite standard antithrombotic protocols. 1 This represents a dramatically higher stroke rate compared to the general TAVI population, where stroke occurs in 6-7% of cases. 2

The hypercoagulable state inherent to APS creates a prothrombotic environment that compounds the already elevated thrombotic risk associated with TAVI itself. 1 The procedure involves:

• Mechanical disruption of calcified native valve tissue, releasing embolic debris 3
• Introduction of a foreign prosthetic valve that generates a prothrombotic surface 3
• Potential for atrial arrhythmias that further increase stroke risk 3

Peri-Procedural Anticoagulation Management

Intraprocedural Strategy

Maintain activated clotting time (ACT) of 200-300 seconds during the procedure using unfractionated heparin. 4 For APS patients specifically, target the higher end of this range (280-300 seconds) given their baseline hypercoagulability. 1

Avoid protamine reversal unless emergent complications such as cardiac perforation or tamponade occur, as reversal increases vascular complications and pericardial tamponade without net benefit. 4

Post-Procedural Anticoagulation for APS Patients

For APS patients, therapeutic anticoagulation with warfarin (INR 2.5-3.5) should be initiated immediately post-procedure and continued indefinitely, as these patients have an independent indication for lifelong anticoagulation beyond the TAVI itself. 2 This differs fundamentally from standard TAVI protocols.

The standard TAVI anticoagulation regimen (aspirin monotherapy or short-term DAPT) is inadequate for APS patients. 4, 5 Instead:

• Continue warfarin indefinitely with target INR 2.5-3.5 (higher than standard mechanical valve targets due to APS thrombotic risk) 2
• Add low-dose aspirin 75-100 mg daily for the first 3-6 months only if bleeding risk is acceptable 2, 4
• Avoid triple therapy (warfarin + aspirin + clopidogrel) as bleeding risk outweighs any theoretical benefit 4

Critical Contraindications in APS Patients

Direct oral anticoagulants (DOACs) are absolutely contraindicated in APS patients, particularly those with triple-positive antibody status, as they have demonstrated increased thrombotic events compared to warfarin. 2 Warfarin remains the only validated anticoagulant for APS. 1

Rivaroxaban 10 mg daily plus aspirin is contraindicated after TAVI even in non-APS patients based on the GALILEO study showing increased mortality and bleeding. 4

Bleeding Risk Considerations

The paradox in APS patients undergoing TAVI is that they require more aggressive anticoagulation while simultaneously facing elevated bleeding risk from:

• Acquired von Willebrand factor deficiency caused by severe aortic stenosis 6
• Angiodysplasia common in elderly patients with aortic stenosis 6
• Vascular access complications (17% incidence) from large-bore catheters in elderly, frail patients 2
• Age-related bleeding vulnerability 6

When combining anticoagulation with antiplatelet therapy is necessary, maintain INR in the lower part of the target range (2.5 rather than 3.0-3.5) to reduce bleeding risk. 4

Monitoring and Surveillance

Neurological assessment should be performed immediately post-procedure and daily during hospitalization, with low threshold for brain imaging if any neurological changes occur. 1 APS patients warrant more intensive monitoring than standard TAVI patients given their 10-fold higher stroke risk.

Continue close INR monitoring with target therapeutic range achievement >70% of the time, as subtherapeutic anticoagulation in APS patients dramatically increases thrombotic events. 2

Common Pitfalls to Avoid

• Never use DAPT alone (aspirin + clopidogrel) as the primary antithrombotic strategy in APS patients - this provides inadequate anticoagulation for their hypercoagulable state 4, 1
• Never discontinue anticoagulation at 3-6 months as done in standard TAVI patients - APS requires lifelong anticoagulation 1
• Never substitute DOACs for warfarin in APS patients despite their convenience, as efficacy is not established and may be harmful 2
• Avoid prasugrel or ticagrelor if triple therapy is considered, as these potent P2Y12 inhibitors dramatically increase bleeding 4

Heart Team Decision-Making

TAVI in APS patients should only proceed after multidisciplinary heart team discussion including cardiology, cardiac surgery, hematology, and neurology to assess whether the thrombotic risk can be adequately mitigated. 2 The 67% cerebrovascular event rate in the published case series suggests that some APS patients may be better served by surgical aortic valve replacement where anticoagulation can be more tightly controlled perioperatively, or by medical management if surgical risk is prohibitive. 1

Factors favoring surgical AVR over TAVI in APS patients include younger age, longer life expectancy, and ability to tolerate cardiopulmonary bypass with controlled anticoagulation. 2