Intraventricular Free-Floating Thrombus in an Impella-Supported Patient

Abstract

We describe the management and clinical decision making in a cardiogenic shock patient with a free-floating left ventricular thrombus found during temporary mechanical support with an Impella CP. The management of these patients can be challenging because there are no guidelines or data to support any particular treatment strategy. (Level of Difficulty: Intermediate.)

Graphical abstract

We describe the management and clinical decision making in a cardiogenic shock patient with a free-floating left ventricular thrombus found during temporary…

A 58-year-old man with progressive heart failure from coronary artery disease presented to our facility in cardiogenic shock in the setting of non–ST-segment elevation myocardial infarction for consideration of advanced heart failure therapies.

Transthoracic echocardiogram (TTE) with Definity contrast (perflutren lipid microsphere, Lantheus Medical Imaging, North Billerica, Massachusetts) was performed at baseline, which showed a severely dilated left ventricle (LV) with LV ejection fraction of 10% without mural thrombus (Figures 1A and 1B, Videos 1A, 1B, and 1C). A transfemoral Impella CP (Abiomed, Danvers, Massachusetts) was implanted without complication as a bridge to durable LV assist device. Anticoagulation with systemic heparin and purge solution was initiated with a systemic goal anti-Xa level between 0.3 to 0.5 IU/ml, per institutional standard.

Figure 1.

Full Series of TTE Images Through Clinical Course

(A) Baseline, no evidence of thrombus. (B) Immediately after Impella placement, no thrombus. (C) During Impella support, thrombus in the left atrium. Impella correctly positioned with inlet 3 cm below aortic annulus, without contact with papillary muscle or posterior wall. Arrow indicates free flowing thrombus in the left atrium. (D) During Impella support, thrombus seen in the left ventricle and unable to exit due to Impella acting as a “stop cock.” Arrow indicates the same thrombus in the left ventricle. (E) Impella removed, no thrombus. (F) Impella removed, Definity-enhanced images without thrombus. IABP = intra-aortic balloon pump; LA = left atrium; LV = left ventricle; TTE = transthoracic echocardiogram.

Online Video 1.

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Baseline transthoracic echocardiogram in apical 4-chamber view pre-Impella implantation demonstrating absence of LV thrombus.

Online Video 2.

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Baseline transthoracic echocardiogram in apical 4-chamber view pre-Impella implantation with Definity contrast. No left ventricular thrombus present.

Online Video 3.

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Baseline transthoracic echocardiogram in apical 2-chamber view pre-Impella implantation with Definity contrast. No left ventricular thrombus present.

On hospital day 6, the Impella developed incessant suction events. TTE showed an unexpected echodense 4.0 cm-by-1.5 cm thrombus floating freely between the left atrium and LV (Figures 1C and 1D, Videos 2 and 3). The patient suddenly developed dysarthria and right-sided facial droop during TTE acquisition, and was found to have large left M1 distribution stroke on computed tomography imaging. During this time, the Impella continued to suction without providing adequate hemodynamic support.

Online Video 4.

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Transthoracic echocardiogram in apical 4-chamber view with thrombus floating in the left atrium while on Impella support.

Online Video 5.

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Transthoracic echocardiogram in apical four chamber view with thrombus floating in the left ventricle while on Impella support, after exiting the left atrium.

The decision was made to remove the Impella and place an intra-aortic balloon pump, while deploying a Sentinel cerebral protection device. Leaving the Impella traversing the aortic valve offered the benefit of providing temporary LV outflow tract “obstruction” to prevent the thrombus from embolizing (Video 4). However, this solution was temporary because the dysfunctional Impella could lead to thrombus propagation if not removed. The residual intraventricular thrombus likely embolized at the time of Impella removal, because repeat TTE no longer visualized the thrombus (Figures 1E and 1F). A second stroke may have been prevented in our patient by the Sentinel device.

Online Video 6.

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Transthoracic echocardiogram in parasternal long axis view with the thrombus floating in the left ventricle and the Impella serving as a “stopcock” to prevent it from embolizing systemically.

The existing published reports on managing free-floating LV thrombi are limited to small case series in which patients with pedunculated LV masses and cardiogenic shock undergo LV ventriculotomy and thrombectomy with concomitant LV assist device implantation (1). The free-floating thrombus would likely have embolized before our patient could undergo surgery, leading to a futile operation. Another option considered was apical LV puncture with aspiration thrombectomy, but this would likely cause shearing and showering of clot fragments distally and further stroke. Tissue plasminogen activator was not an option as the patient was on systemic heparin and had a prohibitively high risk of hemorrhagic conversion.

In summary, the management of free-floating intraventricular thrombi is challenging, with no data to support an optimal treatment strategy. A conservative approach where the Impella is removed with concomitant Sentinel device deployment may be considered.