Combination of mural thrombus and age improves the identification of all-cause mortality following branched endovascular repair

Abstract

Background: In-hospital and 30-day mortality rates of endovascular repair of thoracoabdominal aortic aneurysms shows a significant improvement over open surgery, although we are not seeing a significant difference at 1 year. We assess the hypothesis that a greater mural thrombus ratio within the aorta could function as an indicator of postoperative mortality. Methods:The mural thrombus ratio and preoperative comorbidities of 100 consecutive patients from a single center undergoing endo-debranching between 2012 and 2019 were evaluated. Logistic regression, survival analysis, and decision tree methods were used to examine each variable's association with death at 1 year.Results: At the time of analysis, 73 subjects had 1-year outcomes and adequate imaging to assess the parameters. At 1 year, the overall survival for all subjects was 71.2% (21 died, 52 survived). For patients with a favorable mural thrombus ratio (n ¼ 36), the overall 1-year survival was 86.1% (5 died, 31 survived). The subjects with an unfavorable mural thrombus ratio (n ¼ 37), had an overall 1 year survival of 56.8% (16 died, and 21 survived). The only preoperative mortality factor that was statistically significant between the subjects with an unfavorable mural thrombus ratio was age of the patient. The survival for subjects 75 years and older with an unfavorable mural thrombus ratio was 90% (one died, nine survived) vs only 44.4% survival for subjects less than 75 years with an unfavorable mural thrombus ratio (15 died, 12 survived).Conclusions: This study examined whether a patient's mural thrombus ratio may be an indicator of 1-year survival. These findings suggest that the combination of a patient's aortic mural thrombus ratio and age can function as a preoperative indicator of their underlying cardiac reserve. Identifying patients with low cardiac reserve and fitness to handle the increased cardiac demands owing to the physiologic response to extensive aortic stent grafting before undergoing aortic repair may allow for modification of preoperative patient counseling and postoperative care guidelines to better treat this patient population.

Extent of mural thrombus is not associated with increased 5-year mortality following elective AAA repair

“…The "who and why" of aortic aneurysm mural thrombus is poorly defined. It was thus with great interest that we read the analysis by Patrick et al 7 regarding endovascular repair of TAAA. The concept that patients who have reduced cardiac reserve more readily form mural thrombus as a compensatory mechanism to reduce required stroke volume is quite intuitive.…”

“…The analysis of CT scans was performed by individuals who at that time were blinded as to mortality status. With respect to determining a threshold of mural thrombus to create a categorical variable, a cutoff level of 0.5 for inner to outer diameter was utilized because it correlates with the median amount of thrombus amongst our patients and based on the analogous analysis performed by Patrick et al 7 AUC analysis revealed there was no level of inner-to-outer aortic diameter ratio that corresponded to a meaningful sensitivity or specificity with respect to association with 5-year mortality. The area under the curve was 0.509

Figure 1.Examples of measurement of inner and outer AAA diameters.

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“…[4][5][6] The extent of mural thrombus in thoracoabdominal aortic aneurysms (TAAA) has recently been linked to 1-year mortality following endovascular repair. Patrick et al 7 presented the concept that patients with marginal cardiac reserve compensate by developing aneurysm mural thrombus. Patients with lower ratios of inner to outer aortic 1 College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA diameter (more mural thrombus) were shown to have significantly reduced 1-year survival following endovascular repair of TAAA.…”