Left atrial appendage thrombus; young or old? Role of CMR in definition
© Alnasser et al; licensee BioMed Central Ltd. 2013
Published: 30 January 2013
We report an AF patient who was on Coumadin, presented with acute stroke secondary to LA/LAA thrombus and how CMR played a role in the definition of thrombus age and subsequent management of the patient.
An 83-year-old male with history of AF, DM, cardiomyopathy presented with acute weakness and numbness of the left upper extremity. Two weeks prior to his presentation his INR reportedly ranged from 1.1 to 1.6. However, his INR level was 2.3 at the time of presentation. Upon examination, he was alert and vital signs were stable. Cardiovascular examination revealed irregularly irregular rhythm without any murmurs. Neurological evaluation revealed normal cranial nerves, mild weakness (4/5) of the left upper limb, normal motor strength over the rest of the limbs, normal sensory examination, gait and reflexes were normal.
TEE provides a distinct echo window for evaluation and localization of LA/LAA thrombus compared to TTE. Detection of evolving thrombus in high-risk AF patient's LA/LAA has obvious therapeutic and clinical implications. Recent advances in CMR make it possible to differentiate tissue characters non-invasively based on water content, chemical composition and physical state of the tissue.
This approach has been popularized in our lab and was instrumental in confirming with high confidence not only the nature of the masses but also their age (in case of thrombus) rendering clinically relevant information. We were able to define unequivocally tissue characteristics (virtual histology) as well as determine the heterogeneous ages of the multiple thrombi based solely on T1 and T2 weighted CMR images. The age of thrombus as defined by CMR T2 weighted images correlated with time period where our patient's INR was sub-therapeutic and was presumed to have led to the formation of a new thrombus. We believe CMR imaging is a promising noninvasive tool in the evaluation of LA and LAA thrombus to define the age of the thrombus in addition to localization, helping to refine the intensity of treatment and to prevent further thromboembolic events which in this case was complimentary to the TEE and CT scan.
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