Catheter Thrombectomy of Massive Pulmonary Embolism Secondary to Spongostan Embolisation: A Case Report

ABSTRACT

Novel adjuvant hemostatic agents are increasingly used in surgical procedures to achieve hemostasis. We present a case of embolisation of hemostatic agents during a neurosurgical operation, causing massive PE requiring venoarterial extracorporeal membrane oxygenation support, in a 7‐year‐old boy. Embolectomy was performed using the Penumbra 0.072” catheter with aspiration of blood clots alongside gelatinous clumps of Spongostan and thrombin, leading to angiographic and clinical improvement. A Cook MPA angiographic 5FR catheter and Terumo 0.035” wire were used for catheter repositioning between aspiration attempts. The following day, the patient was weaned from extracorporeal membrane oxygenation, and a day later, he underwent successful extubation. Catheter embolectomy with the Penumbra System can provide safe, rapid relief to a failing right ventricle in cases of massive PE caused by Spongostan.

1. Introduction

Overall incidence of pulmonary embolism in children is estimated at 0.9 per 100,000 children [1], with massive and sub‐massive pulmonary embolism making up only a small fraction. Gold‐standard management of massive pulmonary embolism in the pediatric patient population is poorly defined. Much of our knowledge is limited to case reports, as few studies have been performed looking at retrospective cohorts, those that have are small, single‐center reviews, and no prospective comparative studies exist [2, 3]. Each case is managed according to the expertise of local teams and may be limited by the size of the patient and the high‐profile percutaneous thrombectomy systems. Catheter thrombectomy has been employed more frequently in the adult population, with one meta‐analysis suggesting lower in‐hospital mortality when compared with surgical thrombectomy [4].

Embolisation of Spongostan leading to massive pulmonary embolism has not been described, and best management options are unclear.

Here, a case of percutaneous pulmonary embolectomy is presented in a 7‐year‐old boy suffering from massive pulmonary embolism requiring venoarterial extracorporeal membrane oxygenation (VA ECMO) support, as a result of embolisation of a hemostatic agent.

2. Case Report

A 7‐year‐old, 20 kg, boy with malignant astrocytoma scheduled for neurosurgical Ommaya reservoir placement presented with apparent venous bleeding following neuro‐navigation‐assisted burr hole creation at the start of surgery. Topical application of a mix of thrombin and Spongostan, a gelatin‐based adjuvant hemostatic agent, was used to achieve hemostasis. Moments later, the patient became acutely hypotensive and went into cardiac arrest, with return of spontaneous circulation following a brief resuscitation effort. Urgent transthoracic echocardiography was performed in the operating theater, showing new tricuspid regurgitation, a severely dilated right ventricle with reduced function, and sluggish blood flow in the pulmonary arteries. With a working diagnosis of massive pulmonary embolism, the decision was taken to stop the surgery and transfer the patient for imaging. On CT angiography (Figure 1), bilateral filling defects suspected of being pulmonary emboli were demonstrated in the right main pulmonary artery, the arteries to the right lower lobe, and to the left lower lobe and lingula. The patient was transferred to the pediatric cardiac intensive care unit, and repeat echocardiography demonstrated worsening findings, with an extremely dilated and poorly contractile right ventricle. Due to hemodynamic instability despite maximal doses of inotropic and vasoactive drugs, the patient was urgently placed on femoral VA ECMO bedside.

Figure 1.

Coronal view image from CT angiography demonstrating the bilateral filling defects in the pulmonary arteries leading to the patient's acute deterioration. [Color figure can be viewed at wileyonlinelibrary.com]

Definitive treatment options for massive pulmonary embolism include systemic or catheter‐directed thrombolysis, catheter embolectomy, and surgical embolectomy. Guidelines written for the adult population are difficult to extrapolate to the pediatric patient population. In children with massive PE, thrombolysis is recommended, albeit weakly, as first‐line therapy [5] however, this was contraindicated given our patient's central nervous system neoplasm [6]. Furthermore, pharmacology consultation suggested that thrombolysis was not an appropriate treatment choice due to the mix of both thrombotic elements and Spongostan emboli, unlikely to respond to conventional thrombolysis. Following this, a multidisciplinary discussion between pediatric interventional cardiology, adult interventional cardiology, interventional radiology, and pediatric cardiothoracic surgery was held. Catheter embolectomy was chosen over a surgical approach due to the bilateral and distal locations of the emboli and the desire to avoid cardiopulmonary bypass surgery in an already frail and comorbid patient. Additionally, given the low‐profile of the Penumbra system and the willingness of our interventional radiology colleagues to work together on the case, it was felt that catheter thrombectomy was the safer choice.

Rewiring of a right femoral central line was performed, and a Cook multi‐purpose angiographic 5 French catheter was introduced into the pulmonary arteries. As is usual for catheterization procedures on ECMO, the catheters were introduced under suction, especially when approaching the venous ECMO cannula, with great care taken to avoid introducing air to the ECMO circuit. Measured activated clotting time (ACT) was initially 304 s, due to heparinization for ECMO support, yet after 1 h the ACT decreased to 134 s, and the patient was treated with a heparin bolus of 50 units/kilogram. Initial angiography demonstrated well‐developed left‐sided pulmonary vasculature with a small filling defect in the artery supplying the left lower lobe. Right pulmonary vasculature was poorly demonstrated, with complete occlusion of the artery supplying the right lower lobe and significant occlusion of the right middle lobe (Figure 2). Exchange to a Flexor 6 French guiding sheath was performed using an Amplatz extra stiff 0.035” wire. This was subsequently exchanged for a Cordis 7 French due to incompatibility of the unyielding sheath valve with the soft Penumbra 0.072” catheter. Manual vacuum was created with a 20 mL Luer lock syringe, and repeated aspiration of thrombi was performed from the right lobar pulmonary arteries. Multiple emboli, approximately 3cc in total volume, were extracted, containing a mix of thrombi and white gelatinous material (Figure 3). A Cook multi‐purpose angiographic 5 French catheter and a Terumo 0.035” wire were used to reposition the catheter between aspiration attempts. Significant hemodynamic improvement was noted by the anesthesia and intensive care team who were present for the duration of the case. ECMO support remained on full flow (100 mL/kg) for the entirety of the case. Angiographic improvement was demonstrated, with only remnant, partial filling defects in the arteries supplying the right middle and left lower lobes (Figure 4) at the end of the case.

Figure 2.

Pre‐intervention angiography. Anteroposterior (AP) view demonstrating a paucity of right pulmonary vasculature, complete occlusion of the artery supplying the right lower lobe, and significant occlusion of the right middle lobe. The venous ECMO cannula is seen in the right atrium. Right pulmonary vasculature was poorly demonstrated, with complete occlusion of the artery supplying the right lower lobe and significant occlusion of the right middle lobe Figure 3.

Figure 3.

(a) Before application, thrombin and Spongostan are combined to form a putty. (b) This material forms a very viscous liquid/putty which can be inserted into small spaces. (c) Material aspirated from the patient's pulmonary artery contained gelatinous fragments mixed with thrombus. (d) Thrombin and Spongostan aggregates formed after exposure to blood. [Color figure can be viewed at wileyonlinelibrary.com]

Figure 4.

Post‐intervention angiography: Following manual aspiration with a Penumbra 0.072” catheter, repeat angiography was performed. On AP view, only remnant, partial filling defects remain with improved blood flow to the right lung.

Following a lengthy procedure, the patient was transferred back to the pediatric cardiac intensive care ward, where he was rapidly weaned from ionotropic support, and the subsequent morning was taken off VA ECMO. Extubation was performed the next day with minimal supplemental oxygen requirements, and heparin treatment was replaced with subcutaneous enoxaparin. The patient returned to the oncology ward a week later in good clinical condition, on room air, with no neurological sequelae. Follow‐up CT angiography demonstrated bilateral partial filling defects in the arteries supplying the right middle and lower lobes and the left lower lobe. A month later, echocardiography demonstrated normal right ventricular function and estimated pulmonary artery pressure.

3. Discussion

Our understanding of the best management of massive pulmonary embolism in the pediatric population is limited, and embolism of hemostatic agents causing massive pulmonary embolism has not been described in the literature. Here we present a case of on‐ECMO percutaneous embolectomy using the Penumbra 0.072” catheter, with successful retrieval of thrombi and Spongotan clumps. Due to the nature of the gelatinous Spongostan and thrombin embolus, thrombolysis was deemed unsuitable, although no prior attempts are described in the literature. Due to the large discrete aggregates of Spongostan and thrombin, aspiration was possible using a closely positioned large‐bore catheter. Catheter embolectomy provided immediate relief to the failing right ventricle, facilitating decannulation from VA ECMO after fewer than 24 h. Whilst surgical embolectomy may have been feasible, this case showcases catheter embolectomy as a potential option in a novel and challenging clinical situation. The low‐profile, yet large‐bore, highly flexible Penumbra catheter offers a promising option for percutaneous embolectomy in the pediatric population, even in complex cases with distal embolisation of foreign material and thrombus.

Difficulty in decision making in the context of limited evidence available in massive pediatric pulmonary embolus was heightened in this case by the complexity of the material embolized and by the challenge of applying adult‐derived guidelines to pediatric cases. While pediatric guidelines do exist, these may not take into account the technical advances and the possibilities offered by the Penumbra system, making it highly applicable to more pediatric cases than those treated in the past by the high‐profile adult systems. As such, Monagle et al in their recent American Society of Hematology/International Society on Thrombosis and Haemostasis guidelines for treatment of pediatric venous thromboembolism favor systemic thrombolysis followed by anticoagulation for hemodynamically significant PE [5], rather than invasive treatment, which in this case proved effective. Here, the contraindications to thrombolysis, along with a thorough, multidisciplinary discussion held urgently at the bedside, allowed vital catheter‐based therapy to be performed promptly, overcoming limitations of available literature and clinical guidelines in the setting of a complicated, pediatric massive PE of material not previously described (Central illustration 1).

Central illustration 1.

Novel adjuvant hemostatic agents are increasingly used in surgical procedures. Embolisation of Spongostan causing massive PE requiring ECMO in a seven year‐old was treated with percutaneous embolectomy. Using the Penumbra 0.072” catheter, blood clots and gelatinous Spongostan and thrombin clumps were aspirated, providing rapid relief to a failing right ventricle. [Color figure can be viewed at wileyonlinelibrary.com]

4. Conclusion

Management of rare and life‐threatening disease processes is a challenge for healthcare providers due to the lack of clear guidelines for seldom encountered disease processes and limited personal and organizational experience. Pediatric massive pulmonary embolism, and specifically, embolism complicated by the presence of novel adjuvant hemostatic agents, presents such a challenge. Multidisciplinary consultation allowed for swift decision‐making and rapid treatment by the appropriate team. Catheter thrombectomy may be successfully used to treat pediatric patients suffering with massive pulmonary embolism, even in the case of embolised Spongostan, and provide rapid relief to a failing right ventricle.

Funding

The authors have nothing to report.

Ethics Statement

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Informed consent was obtained from the legal guardian of the participant in this study.

Consent

Consent for publication was obtained from the legal guardian of the participant in this study.

Conflicts of Interest

The authors declare no conflicts of interest.

Supporting information

Supporting File 1

Supporting File 2

Data Availability Statement

All data underlying the results are available as part of the article, and no additional source data are required.