What is the safety and efficacy of the pressure cooker technique for embolization (endovascular embolization)?

Pressure Cooker Technique for Embolization

The pressure cooker technique is a safe and effective advanced endovascular method that facilitates increased complete obliteration rates of brain arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs) through prolonged, controlled injections of liquid embolic agents, with demonstrated high cure rates and acceptable morbidity when performed in high-volume centers. 1

Technical Mechanism and Rationale

The pressure cooker technique creates an anti-reflux plug around the microcatheter tip to achieve wedge-flow conditions, enabling deeper penetration of liquid embolic agents while minimizing backflow and non-target embolization. 1, 2, 3

• The technique uses detachable-tip microcatheters combined with DMSO-compatible balloon microcatheters and ethylene-vinyl alcohol (EVOH) copolymer-based liquid embolic agents (such as Onyx). 1
• The anti-reflux plug is created using coils and glue around the microcatheter tip, allowing continuous, forceful injection with more comprehensive nidal penetration. 3
• This approach enables treatment of macrofistulous AVMs that would otherwise be difficult to embolize completely. 3

Clinical Efficacy

Transvenous Pressure Cooker Technique

The transvenous pressure cooker technique demonstrates exceptional outcomes for high-grade AVMs, with complete occlusion rates of 100% and procedural mortality of 0% in the most recent series. 1

• A 2022 series of 22 patients with high-grade AVMs treated with transvenous embolization using balloon microcatheters for temporary arterial flow arrest achieved complete AVM occlusion in all patients, with procedural morbidity of 4.5% and mortality of 0%. 1
• A 2021 series by Koyanagi et al. using the transvenous pressure cooker technique in 51 patients with predominantly high-grade AVMs (SM grade III-V in 71%) reported high occlusion rates with no procedure-related mortality. 1
• Three patients (6%) experienced intracranial hemorrhage related to the procedure, with permanent neurological deficits in one patient (2%) at last follow-up. 1

General Embolization Outcomes

• A 2023 retrospective review of 15 consecutive patients (7 AVMs, 8 DAVFs) treated with the pressure cooker technique achieved the primary safety endpoint in all cases with no intraprocedural complications and no difference between pre- and post-procedure modified Rankin Scale scores. 2
• Complete embolization occlusion of target vessels was documented on final control angiography in all cases. 2

Safety Profile

The pressure cooker technique demonstrates acceptable safety when performed in experienced centers, though complication rates vary with institutional volume and patient selection. 1

• Procedural morbidity rates range from 2.7% to 8% depending on AVM complexity and institutional experience. 1
• Procedure-related mortality ranges from 0% to 3% across published series. 1
• The technique is safest when applied to appropriately selected lesions in high-volume centers with experienced operators. 1

Indications for Use

Transvenous Approach with Pressure Cooker Technique

The transvenous pressure cooker technique is indicated for: 1

• Small (diameter <3 cm) and compact AVM nidus
• Deep or eloquent AVM location
• Hemorrhagic presentation
• Single draining vein
• Inaccessible arterial pedicles
• Exclusive arterial supply by perforators or en passage feeding arteries
• Staged curative treatment of large and high Spetzler-Martin grade brain AVMs deemed otherwise inoperable

General Curative Embolization

Curative embolization using the pressure cooker technique is most appropriate for: 1

• Small to medium-sized lesions with compact niduses
• Limited arterial and venous pedicles from a single vascular territory
• Spetzler-Martin grades I, II, and III AVMs
• Lesions not amenable to multimodal therapies or stand-alone microsurgery/stereotactic radiosurgery

Critical Technical Considerations

Superselective catheterization with microcatheter positioning as close to the fistula point as possible is essential to ensure complete nidal obliteration and minimize complications. 4

• Avoiding proximal arterial occlusion without nidal penetration is crucial, as it promotes collateral formation and makes subsequent treatment more difficult. 4
• Testing the complete obstruction by the plug with contrast media injection reduces the risk of reflux. 2
• Simplified variations using nylon coils instead of platinum coils and acrylic glue can provide safer, more precise, and faster plug creation. 5

Critical Pitfalls to Avoid

Occluding the draining vein before complete nidal obliteration can cause catastrophic hemorrhage from venous hypertension. 4

• Partial embolization without intent to cure should be avoided, as it does not reduce long-term hemorrhage risk and may increase surgical difficulty if needed later. 4
• Early and subacute hemorrhagic complications can occur after partial treatment due to altered hemodynamics or inadvertent occlusion of draining veins. 6
• Careful blood pressure monitoring and control in the postoperative period are critical to prevent hemorrhagic complications. 6

Post-Procedure Management

Strict blood pressure control is essential in the immediate post-embolization period to prevent hemorrhagic complications from flow redistribution. 4

• Neurological intensive care monitoring for at least 24 hours is required to detect potential complications. 7
• Continuous assessment of neurological and hemodynamic parameters with arterial catheter monitoring is recommended. 7
• Target normotension with continuous monitoring for at least 24 hours post-procedure. 4

Comparison with Other Embolic Agents

• EVOH (Onyx) demonstrates higher AVM cure rates compared to n-butyl cyanoacrylate (n-BCA), but also has higher procedural complication rates. 1
• Magic Glue (N-hexyl cyanoacrylate) shows similar extent of embolization to NBCA, with less traction force necessary to withdraw trapped microcatheters. 8

Role in Multimodal Treatment

The pressure cooker technique has expanded the role of endovascular therapy to more complex and deeper-seated lesions that are neither amenable to multimodal therapies nor stand-alone microsurgery or stereotactic radiosurgery. 1

• Embolization before surgical resection can be useful to reduce intraoperative blood loss, morbidity, and surgical complexity (Class IIa recommendation, Level B-NR evidence). 1
• The technique enables angiographic cure for larger or more complex deep brain AVMs (SM >3) in high-volume centers. 1