SCMR 22nd Annual Scientific Sessions
Description of Clinical Presentation:
A 65 year old male presented with chest pain, two months after a ST elevation myocardial infarction(MI). Patient underwent percutaneous coronary intervention during the initial event, however the culprit vessel (obtuse marginal) was not intervened upon as patient had already completed infarction. Transthoracic echocardiogram (TTE ) and chest CT (fig 1) on current admission showed a left ventricular (LV) outpouching consistent with a post-MI complication. Further evaluation with cardiac MR (CMR) and 3D printing was performed. Patient subsequently underwent surgery and the findings are presented below.
Diagnostic Techniques and Their Most Important Findings:
TTE (fig 1):There is thinning and akinesis of the basal to mid lateral segments. The myocardial contours are unusual with an irregular left ventricular outpouching (LVO) in the inferior segment. In some views the ostium of the LVO was smaller than the length, suggesting pseudoaneurysm (ratio 0.5).
CMR (fig2): The anterolateral wall is thinned, infarcted and aneurysmal. There appears to be an additional LVO with the edge of the inferior wall and anterolateral wall forming the neck which is narrower than the width of the LVO, raising the concern for a pseudoaneurysm. There is a large mural thrombus seen in the base of the LVO on late gadolinium enhancement imaging. The pseudotumor-like thickening of the inferolateral segment noted on the TTE was confirmed to be viable hyper-contractile myocardial tissue displaced anteriorly by the posteriorly located LVO. While the extensive mural thrombus was easily identified on CMR, it was difficult to distinguish the thrombus from non-contractile myocardium on the TTE. The end diastolic and end systolic volumes excluding the secondary LVO was 159ml and 114ml. The volume of the LVO was 31ml.
3D printing and Surgical findings: A STL file (stereoLithography file) was generated from the segmented chest CT images and a 3D flexible resin model was created using a Form Labs 3D printer. The 3D model was used by the surgeon to plan aneurysectomy and Dor procedure with patch closure (fig 2 & 3). Based on the volume assessment, the surgeon made sure to have a left ventricular volume of at least 120 ml prior to the patch closure.
Learning Points from this Case:
It remains a clinical challenge to differentiate between LV aneurysm and pseudoaneurysm. In the case of a true aneurysm, the outpouching is from the thinned out myocardium, with preserved myocardial integrity. A pseudoaneurysm is formed due to myocardial rupture that is contained by the pericardium, organizing thrombus and hematoma. LV pseudoaneurysms are often located in the inferior and diaphragmatic surface and have a narrow neck with the ostium of the LVO smaller than the length (<0.5). In the era of multimodality imaging and 3D printing, there is a high degree of precision in diagnosis and management of complicated cardiac pathology. Quantitative volumetric data from multimodality imaging and 3D printing were helpful in surgical planning of post surgical LV volumes in this case.