Micro-CT-Based Quantification of Extracted Thrombus Burden Characteristics and Association With Angiographic Outcomes in Patients With ST-Elevation Myocardial Infarction: The QUEST-STEMI Study

Abstract

Background: Angiographic detection of thrombus in STEMI is associated with adverse outcomes. However, routine thrombus aspiration failed to demonstrate the anticipated benefit. Hence, management of high coronary thrombus burden remains challenging. We sought to assess for the first time extracted thrombotic material characteristics utilizing micro-computed tomography (micro-CT).Methods: One hundred thirteen STEMI patients undergoing thrombus aspiration were enrolled. Micro-CT was undertaken to quantify retrieved thrombus volume, surface, and density. Correlation of these indices with angiographic and electrocardiographic outcomes was performed.Results: Mean aspirated thrombus volume, surface, and density (±standard deviation) were 15.71 ± 20.10 mm3, 302.89 ± 692.54 mm2, and 3139.04 ± 901.88 Hounsfield units, respectively. Aspirated volume and surface were significantly higher (p < 0.001) in patients with higher angiographic thrombus burden. After multivariable analysis, independent predictors for thrombus volume were reference vessel diameter (RVD) (p = 0.011), right coronary artery (RCA) (p = 0.039), and smoking (p = 0.027), whereas RVD (p = 0.018) and RCA (p = 0.019) were predictive for thrombus surface. Thrombus volume and surface were independently associated with distal embolization (p = 0.007 and p = 0.028, respectively), no-reflow phenomenon (p = 0.002 and p = 0.006, respectively), and angiographically evident residual thrombus (p = 0.007 and p = 0.002, respectively). Higher thrombus density was correlated with worse pre-procedural TIMI flow (p < 0.001). Patients with higher aspirated volume and surface developed less ST resolution (p = 0.042 and p = 0.023, respectively).Conclusions: Angiographic outcomes linked with worse prognosis were more frequent among patients with larger extracted thrombus. Despite retrieving larger thrombus load in these patients, current thrombectomy devices fail to deal with thrombotic material adequately. Further studies of novel thrombus aspiration technologies are warranted to improve patient outcomes.Clinical Trial Registration: QUEST-STEMI trial ClinicalTrials.gov number: NCT03429608 Date of registration: February 12, 2018. The study was prospectively registered.

Association of GRACE Risk Score with Coronary Artery Disease Complexity in Patients with Acute Coronary Syndrome

“…This could be explained by the fact that the SYNTAX score is not always increased in patients with STEMI, and the calculation of the SYNTAX score was performed using a modified strategy for scoring the infarct-related artery (IRA) [25]. In addition, the existence of further parameters, apart from CAD complexity (e.g., pain-to-balloon time and thrombus burden), could affect outcomes in STEMI patients [41,42]. However, a high GRACE score in STEMI patients presenting to non-PCI capable hospitals could be an important indicator for an early transfer to a PCI-center just after thrombolytic treatment.…”

Micro-CT for Biological and Biomedical Studies: A Comparison of Imaging Techniques

“…In biomedical research, micro-CT has been used in a wide range of scientific fields such as musculoskeletal, neurological, cardiorespiratory, gastrointestinal research, and longitudinal studies for treatment effects (e.g., [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]). In recent years, it has been used also in biological fields such as taxonomy, ecology, and developmental research (e.g., [ 18 , 19 , 20 ]).…”

“…Micro-CT imaging was utilised in an effort to evaluate the impact of aspirated thrombus burden on the post-aspiration clinical and angiographical outcomes of patients with ST-Elevated Myocardial Infarction (STEMI) [ 13 ]. The prognostic significance of initial angiographic and post-aspiration residual thrombus burden has been already investigated via recent optical coherence tomography studies [ 87 ].…”

“…Cross-section images were loaded into the software CT Analyser v.1.14.4.1 (CTAn, Bruker, Kontich, Belgium) to extract measurements for the volume and density of thrombi as mean greyscale values (±Standard Deviation), which were also converted to Hounsfield units (HU). Furthermore, erythrocyte-rich and platelet-rich regions of the thrombus were segmented through the CTAn software using different grey-level values (for more details, see [ 13 ]). Finally, volume renderings of the samples were created using the SkyScan’s CTVox software ( Figure 10 a).…”

“…: 0.991–0.996), and 0.987 (95% C.I. : 0.966–0.993), respectively) [ 13 ]. The correlation of micro-CT images with clinical and angiographical parameters yielded that larger thrombus burden was associated with outcomes suggestive of poor prognosis in patients with STEMI, since higher thrombus volume and surface were independently associated with distal embolisation ( p = 0.007 and p = 0.028, respectively), no-reflow phenomenon ( p = 0.002 and p = 0.006, respectively), and angiographically evident residual thrombus ( p = 0.007 and p = 0.002, respectively) [ 13 ].…”