Case presentation
We report on a 7-month-old boy (4.2 kg/60 cm) with severe primary immunodeficiency disorder who was referred for an infected atrial thrombus secondary to a jugular central line. The patient was diagnosed with leukocyte adhesion deficiency, had a history of recurrent bacterial infections with growth delay, and was listed for haematopoietic stem cell transplantation. He had a triple lumen right internal jugular vein line to receive intravenous antibiotics for Klebsiella pneumoniae septicaemia. The echocardiogram showed a thrombus located at the atrial septum starting from the superior caval vein down to the mid-part of the atrial septum. The thrombus was teardrop-shaped with a wide base adherent to the interatrial wall and a friable tail moving freely in the mid-right atrium and across the tricuspid valve (Figure 1a, Video 1, 2). He also had other smaller thrombus fixed to the mitral valve apparatus without mitral valve regurgitation or stenosis (Figure 1, Video 2). There was no intracardiac shunt or anomaly. The chest CT scan showed multiple lesions in both lungs and branch pulmonary arteries consistent with infected micro-embolic events and mycotic aneurysms.
Figure 1. (a) Modified four cavities subcostal ultrasound view showing the atrial thrombus adherent to the interatrial wall with a flimsy tail across the tricuspid valve (white arrow). Note the smaller thrombus fixed to the mitral valve apparatus (blue arrow). (b) Postoperative transthoracic ultrasound showing complete atrial thrombus removal.
We discussed the case during a multidisciplinary meeting and concluded that the atrial thrombus is showering infected embolic clots into the pulmonary circulation. The jugular catheter was then removed and the child received intravenous meropenem and amikacin combination therapy and a therapeutic dose of subcutaneous enoxaparin, which brought his inflammatory markers down without normalising. Two weeks later, the inflammatory markers were going up again, and ultrasound assessments showed that the thrombus size was increasing. A decision was made to remove the atrial thrombus percutaneously.
A 6-Fr right femoral access was obtained under fluoroscopic guidance to make sure the guiding wire was not crossing the upper part of the inferior caval vein. A 4-Fr multipurpose glide catheter and a J-tip 0.035-inch Terumo wire were navigated carefully into the superior caval vein. After parking a 0.035-inch Emerald PTFE Guidewire from Cordis, the glide catheter was exchanged with an 8.5-Fr Destino™ Reach steerable guiding sheath from Biotronik. Under transoesophageal ultrasound and biplane fluoroscopy, the tip of the steerable sheath was deflected 75 degrees toward the interatrial septum. We advanced a 7-Fr 130 cm long Penumbra Lightning® 7 aspiration catheter (XTORQ Tip) through the right femoral vein, connected to the Lightning® aspiration tubing and the Penumbra ENGINE® (Figure 2). We exteriorised the tip of the catheter a few millimetres beyond the tip of the sheath. We confirmed the catheter position on transoesophageal ultrasound and used the manual on/off suction mode. The clot came out fragmented to the collector tank. The aspiration catheter was then moved caudally to sweep down the intra-atrial septum. Ultrasound showed that the clot was removed. 60 ml of blood loss was replaced during the procedure with cross-matched blood. No change in serum haemoglobin was noted. The procedure time was 15 minutes. The child was extubated on the table. The thrombus was sent for culture and came back positive for Klebsiella pneumoniae. Next day, echocardiogram showed normal caval flow with an absence of effusion, tricuspid regurgitation, and residual thrombus (Figure 1b). The c-reactive protein levels came down from 220 mg/ml to 76 mg/ml after 3 days post-procedure. He was discharged from the hospital at 3 weeks postoperative after two negative blood cultures, a c-reactive protein at 15 mg/dl, and a negative procalcitonin. At 6 weeks of follow-up, the patient is alive, under enoxaparin with no procedure-related complication.
Figure 2. Illustration of components of the Pneumbra’s Indigo Lightning peripheral mechanical thrombectomy system. (a) Lightning® 7 aspiration catheter (black arrow) and SeparatorTM 7 (grey arrow). (b) Penumbra ENGINE® aspiration source and Lightning aspiration tubing.
Discussion
Antithrombotic treatment encompasses a range of interventions, including thrombolysis, pharmacologic anticoagulation, and thrombectomy (either catheter-based or surgical), which may be employed individually or in combination. Reference Williams1 The more intensive treatment, the more likely the risk of bleeding increases. Thrombolytics have bleeding risks, particularly in small infants and vulnerable patients. In addition, the risk of intracranial and other major haemorrhage remains a main limiting factor to the use of thrombolytics in patients already on high-dose heparin. Reference Williams1 Local thrombolytic therapy has been used successfully in some infants, but the experience is limited. Reference Williams1 In this patient, we chose aspiration thrombectomy with Indigo because this novel device offers two key advantages. It does not require the use of thrombolytics and provides immediate thrombus removal. However, despite the favourable outcome, one could still argue for the merits of attempting thrombolytic therapy in this specific scenario, which involves infected and disseminated multiple lesions, besides the aspirated right atrial one. Furthermore, it is prudent to consider the composition and age of the thrombus, as these factors can influence the puncture-to-reperfusion time, the number of required manoeuvres, and ultimately, the associated clinical outcomes. Reference Shimizu, Hatakeyama and Saito2 Larger real-world studies will provide a clearer understanding of the impact of thrombus characteristics in paediatric cases.
Mechanical thrombectomy catheters are extensively documented as both primary and adjunctive therapies for thrombus removal in adults and older children. Particularly, the Indigo device has been applied recently in adult-sized patients in the management of pulmonary embolism, peripheral arterial and venous thrombus, and coronary vessel occlusion. Reference Sista, Horowitz and Tapson3– Reference Mathews, Parikh and Wu5 However, data on the intracardiac use of this device in children is limited to one case report. Soszyn N et al. from Children’s Hospital Colorado described in January 2023 the case of a 53-day-old girl with central shunt thrombosis in the setting of pulmonary atresia where they successfully applied the Indigo aspiration system to remove the thrombus from her central shunt and left pulmonary artery facilitating stent placement in her narrowed left pulmonary artery. Reference Soszyn, Morgan, Kim and Zablah6 Subsequently, the same team reported an extracardiac use of the Indigo aspiration system to remove a thrombus from the pericardial space of a 4-year-old boy with complex pericardial effusion associated with kaposiform lymphangiomatosis. Reference Soszyn, Leahy and Morgan7 Herein, we report the second intracardiac use of the Indigo aspiration system in a small infant with safety and immediate efficacy.
In comparison to alternative mechanical thrombectomy systems like the AngioJet rheolytic, the Penumbra® Indigo system stands out as a sophisticated, computer-assisted device. Reference Qureshi, Petit, Crystal, Liou, Khan and Justino8,Reference Yamada, Adams, Guimaraes and Schönholz9 The built-in microprocessor features a proprietary thrombus removal algorithm that automatically controls the valve in the tubing to provide nearly pure continuous or intermittent aspiration (-29 inHg or 98.2 kPa) with intraprocedural audio-visual cues. This algorithm helps the operator quickly identify the thrombus location and detect patent flow to reduce potential blood loss. The device has three components: an aspiration catheter, a separator, and a pump. The separators are intended to mobilise the clot and clean the catheter lumen, therefore restoring flow for continuous aspiration (Figure 2).
In this patient, the use of the low-profile 7-Fr device effectively removed the atrial thrombus with minimal blood loss, vessel trauma, or cardiac injury. While the aspiration catheter boasts a soft atraumatic edge, excessive manipulation of the separator in distal anatomies or near intracardiac valves may result in vascular injury. Consequently, steerable guiding sheath, double fluoroscopic, and most importantly transoesophageal ultrasound guidance were essential to navigate the aspiration catheter with extra care and prevent it from going through the tricuspid valve or to the right atrial appendage.
Indigo continuous aspiration thrombectomy (CAT) catheters range in diameter from 3.4 to 12 Fr and lengths from 50 to 150 cm. However, Penumbra’s Indigo aspiration system in the Middle East has been approved and introduced with Lightning® 7 and Lightning® 12, featuring CAT7 and CAT12 aspiration catheters, respectively. As of now, the utilisation of the Indigo aspiration system is confined to paediatric patients with a body weight suitable for a 7-Fr catheter.
Conclusion
The Penumbra Indigo aspiration system is a viable new tool in the armamentarium of paediatric cardiologists to safely remove intracardiac thrombus in children without increasing the systemic risk of bleeding.
Supplementary material
The supplementary material for this article can be found at https://doi.org/10.1017/S104795112402599X
Financial support
None.
Competing interests
None declared.
Ethical standard
The procedure contributing to this work is by the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments. We obtained written informed consent from the patient’s parents to use and publish their clinical data.
