Pericoronary adipose tissue attenuation in patients with acute aortic dissection based on coronary computed tomography angiography

Background

Periaortic fat is associated with coronary disease. Thus, it was hypothesized that the inflammation associated with acute aortic dissection (AAD) spreads to pericoronary adipose tissue (PCAT) via thoracic periaortic fat. Pericoronary adipose tissue attenuation (PCATa) serves as a marker for inflammation of perivascular adipose tissue (PVAT). This study sought to examine PCATa in individuals diagnosed with AAD.

Methods

Consecutive patients with chest pain from May 2020 to September 2022 were prospectively enrolled in this study and underwent coronary computed tomography angiography (CCTA) and/or aorta computed tomography angiography (CTA). Based on the results of the CTA, the patients were divided into the following two groups: (I) the AAD group; and (II) the non-AAD group. PCATa of the right coronary angiography (RCA), left anterior descending (LAD), and left circumflex (LCx) was quantified for each patient using semi-automated software. The PCATa values were compared between the AAD and non-AAD patients according to the atherosclerosis of the coronary arteries. Similarly, the PCATa values of the AAD patients were compared between the preoperative and postoperative steady states.

Results

A total of 136 patients (42 female, 94 male; mean age: 63.3±11.9 years) were divided into the two groups according to the presence of aortic dissection on CTA. The RCAPCATa, LADPCATa, and LCxPCATa values were significantly higher in the AAD subjects than the non-AAD subjects, regardless of the presence or absence of atherosclerosis in the coronary arteries [-85.1±9.3 vs. -92.9±10.0 Hounsfield unit (HU); -83.2±7.4 vs. -89.9±9.1 HU; -77.5±8.4 vs. -85.6±7.9 HU, all P<0.001). The preoperative RCAPCATa, LADPCATa, and LCxPCATa values were higher in the AAD patients than the postoperative steady-state patients (-82.9±8.7 vs. -97.6±8.8 HU; -79.8±7.6 vs. -92.8±6.8 HU; -74.6±7.1 vs. -87.7±6.9 HU, all P<0.001). According to the multivariable logistic regression analysis, high RCAPCATa and LADPCATa values were associated with AAD regardless of the degree of stenosis [odds ratio (OR) =0.014; 95% confidence interval (CI): 0.001-0.177; P=0.001 and OR =0.010; 95% CI: 0.001-0.189; P=0.002].

Conclusions

PCATa on computed tomography was increased in patients with AAD regardless of the presence or absence of coronary artery disease (CAD). This suggests that vascular inflammation is present in AAD independent of CAD. Further research should be conducted to investigate the potential of this imaging biomarker to predict AAD and monitor patients' responses to therapies for AAD.

The relationship between false-lumen area ratio and renal replacement therapy after acute aortic dissection repair on bilateral artery cannulation: a cross-sectional study

Background

Malperfusion poses a serious challenge to organ function in the repair of acute aortic dissection (AAD). The purpose of this study was to explore the segment change of false-lumen area ratio (FLAR; the ratio of the maximal false-lumen area to the total lumen area) in the descending aorta and its relationship with renal replacement therapy (RRT) after total aortic arch (TAA) surgery.

Methods

A total of 228 patients with AAD who received TAA using perfusion mode right axillary and femur artery cannulation between March 2013 and March 2022 were included in a cross-sectional study. The descending aorta was divided into 3 segments: the descending thoracic aorta (S1), the abdominal aorta above the ostium of the renal artery (S2), and the abdominal aorta between the ostium of the renal artery and the iliac bifurcation (S3). The primary outcomes were postoperative segmental FLAR changes in the descending aorta, which were observed using computed tomography angiography before the patients were discharged from the hospital. The secondary outcomes were RRT and 30-day mortality.

Results

The total potencies in the false lumen were 71.1%, 95.2%, and 88.2% in S1, S2, and S3. The postoperative/preoperative ratio of the FLAR was higher in S2 than that in S1 and S3 (S1: 67%±14%; S2: 80%±8%; S3: 57%±12%; all P values <0.001). For the patients undergoing RRT, there was a higher postoperative/preoperative ratio of the FLAR for the S2 segment (85%±7% vs. 79%±8%; P<0.001) and higher mortality (28.9% vs. 7.7%; P<0.001) after AAD repair compared with patients in the no-RRT group.

Conclusions

This study demonstrated there was less attenuation of the FLAR on the abdominal aorta above the ostium of the renal artery in the whole descending aorta after AAD repair with intraoperative right axillary and femur artery perfusion mode. The patients needing RRT were associated with less postoperative/preoperative change of the FLAR and worse clinical outcomes.

Changes in aortic collagen in β-aminopropionitrile-induced acute aortic dissection

Background

The precise role collagen plays in acute aortic dissection (AAD) was investigated in an animal model of β-aminopropinitrile (BAPN)-induced AAD.

Methods

The 30 3-week-old male specific-pathogen free (SPF)-grade Sprague-Dawley (SD) rats were randomly divided into two groups: 10 in the Control group and 20 in the Model group. The Model group was treated with 0.1% BAPN for 4 weeks, while the Control group received untreated water. Histopathological staining and western blot were used to detect changes of the extracellular matrix (ECM) and collagen content in the aorta.

Results

At the end of the experiment, the incidence of AAD was 25%, the aortic ECM of surviving rats was severely damaged, and the arrangement was disordered. Fibroblast cells are unevenly distributed, with wide gaps, collagen fibers were also distributed unevenly in a disordered arrangement and their thickness was uneven. The elastic membrane disappeared over a large area. Compare to Control group, the Collagen types I, III and their subunits were upregulated (P<0.05), while matrix metalloproteinase (MMP) 2 and MMP9 were downregulated in the aorta of Model group (P<0.05).

Conclusions

In the animal model of BAPN-induced AAD, collagen types I, III and subunits were increased, while MMP2 and MMP9 were decreased in thoracic aorta, which may lead to stiffness of the aorta and be the cause of dissection.

Admission LDL-C and long-term mortality in patients with acute aortic dissection: a survival analysis in China

BACKGROUND

The level of blood lipid is closely related to prognosis in cardiovascular diseases. This study aims to analyze the effect of serum low-density lipoprotein cholesterol (LDL-C) levels on the long-term mortality in acute aortic dissection (AAD). A lower admission LDL-C level is associated with an increased risk of long-term mortality in AAD.

METHODS

We analyzed the data of 284 patients with AAD admitted to the First Affiliated Hospital of Shantou University Medical College from February 2016 to September 2019. Patients were followed up post-discharge. All patients were divided into either an LDL-C low-level group or an LDL-C high-level group according to the optimal cut-off point obtained by the receiver operating characteristic (ROC) curve. The endpoint outcome was long-term mortality in AAD. A survival analysis and Cox proportional hazards model were used.

RESULTS

According to the Youden index, the optimal cut-off point for LDL-C was 2.755 mmol/L. The Kaplan-Meier survival analysis curves showed that the long-term mortality of the LDL-C low-level group (<2.755 mmol/L) was significantly higher than that of the LDL-C high-level group (≥2.755 mmol/L) (log-rank χ²=13.912, P<0.001). After multivariate Cox regression analysis, LDL-C <2.755 mmol/L was still significantly associated with long-term mortality in AAD (HR=3.287, 95% CI: 1.637-6.600, P=0.001). In addition, cystatin C was also an independent risk factor for the long-term prognosis of AAD (HR=1.253, 95% CI: 1.057-1.486, P=0.009).

CONCLUSIONS

A lower admission LDL-C level may be associated with an increased risk of long-term mortality in AAD.

Effects of dexmedetomidine on heart rate control and pre-operative outcome in patients with acute aortic dissection: a propensity-matched analysis

BACKGROUND

The total survival rate in patients with acute aortic dissection (AAD) has been greatly improved because of surgical technique advances. However, the pre-operative mortality rate remained high. In this study, we sought to evaluate the effects of dexmedetomidine (DEX) on heart rate control and preoperative outcome in AAD.

METHODS

Retrospectively enrolled 461 patients who were diagnosed with AAD during the first 7-day after admission and divided into two groups according to the use of intravenous DEX: DEX group (91 patients) and Control group (370 patients). The heart rate and systolic blood pressure (SBP) level in both groups were recorded, and the incidence of aortic dissection rupture and pre-operative survival rates within 7 days were considered as the primary clinical outcomes.

RESULTS

Compared to the Control group, heart rate of DEX group in the early 3 hours was significantly higher (P=0.009), and the 24-hour heart rate fluctuation was smaller (P=0.012). There was no difference in the systolic blood pressure (SBP) between the two groups, but the 24-hour fluctuation of SBP in DEX group was less (P=0.003). We performed a propensity-matched analysis to minimize selection bias and found that there were 7 (7.9%) patients in the DEX group occurred acute pulmonary edema, 17 (19.1%) patients in the Control group (P=0.047). And the pre-operative survival rates within 7 days were significantly improved in DEX group (P=0.004). And the pre-operative survival rates within 7 days were significantly improved in DEX group (P=0.004).

CONCLUSIONS

DEX can be beneficial to facilitate heart rate control, keep SBP more steady, and reduce the incidence of pre-operative aortic rupture in patients with AAD.

Oxygenation impairment in patients with acute aortic dissection is associated with disorders of coagulation and fibrinolysis: a prospective observational study

Background

Stanford type-A acute aortic dissection (AAD) is typically accompanied by oxygenation impairment before surgery. In addition, inflammation, coagulation and fibrinolysis also impair blood oxygenation. However, our understanding of the concentration of these factors in bronchoalveolar lavage fluid (BALF) has not been reported. The objective of the study was to investigate the impact of preoperative acute lung injury (ALI) on postoperative oxygenation impairment and to explore the effect of coagulation and fibrinolysis in blood and BALF.

Methods

This investigation utilized a prospective observational study design, which was registered at www.clinicaltrials.gov (identifier NCT01894334). The study included 53 patients undergoing surgery for Stanford type-A AAD at an academic hospital in China between October 2013 and July 2014. Preoperative ALI was identified according to the oxygenation index calculated by the PaO₂/FiO₂ ratio. The subjects were divided into the ALI group (oxygenation index ≤300 mmHg) or the control group (oxygenation index >300 mmHg). The primary outcome was patient oxygenation index, while secondary outcomes were concentrations of tissue factor (TF), tissue factor pathway inhibitor (TFPI), and plasminogen activator inhibitor-1 (PAI-1) in serum and BALF.

Results

The incidence of preoperative ALI for Stanford type-A AAD patients was 41.5%. Stanford type-A AAD patients with preoperative ALI had a lower postoperative oxygenation index (104.6±31.7 vs. 248.7±48.0 mmHg, P<0.001), higher concentrations of TF in serum and BALF (F=133.67, P<0.001; F=68.14, P<0.001), higher concentrations of TFPI in serum and BALF (F=31.98, P<0.001; F=45.58, P<0.001), and higher concentrations of PAI-1 in serum and BALF (F=213.88, P<0.001; F=107.95, P<0.001) when compared with those without preoperative ALI. Type-A AAD patients also showed a greater loss of blood (1,524±458 vs. 1,175±327 mL, P=0.040), longer mechanical ventilation time in the ICU (27.24±8.37 vs. 17.33±7.36 h, P<0.001), longer total stay in the ICU (42.27±10.85 vs. 33.45±9.05 h, P=0.002), and longer total hospital stay (17.77±5.00 vs. 13.48±3.97 days, P=0.001). Multivariate linear regression analysis indicated that preoperative PAI-1 in BALF, and TF in both serum and BALF were significantly associated with preoperative oxygenation impairment in patients with Stanford type-A AAD.

Conclusions

Preoperative ALI caused more serious postoperative oxygenation impairment for Stanford type-A AAD, and coagulation and fibrinolysis appear to play critical roles in this process. Preoperative PAI-1 in BALF and TF in both serum and BALF were significant factors related to the occurrence of preoperative oxygenation impairment for Stanford type-A AAD.

Changes in coagulation factor XII and its function during aortic arch surgery for acute aortic dissection-a prospective observational study

Background

Changes in the intrinsic coagulation pathway during aortic arch surgery in patients with acute aortic dissection (AAD) have not yet been reported. The aim of this study is to describe the changes in intrinsic coagulation factor XII, explore its function and find a new target for the treatment of coagulopathy during surgery.

Methods

Eighty-eight patients undergoing emergent surgery for AAD were enrolled. Changes in the intrinsic and extrinsic coagulation pathways were evaluated at 5 different timepoints during the perioperative period by measuring intrinsic coagulation factor XII, extrinsic coagulation factor VII and some intrinsic upstream stimulating factors. The 88 patients were also divided into two groups according to whether reoperation for coagulopathy was required after surgery.

Results

Both coagulation factors XII and VII demonstrated a significant and similar change during the perioperative period. These factors decreased significantly during hypothermia circulation arrest (P<0.001) and recovered to normal levels by 24 hours after surgery. Among the intrinsic upstream stimulating factors, bradykinin (BK) demonstrated a similar changing trend with coagulation factors XII and VII, while other stimulating factors did not. However, compared with factor VII, factor XII demonstrated a greater decline during surgery. The proportion of decline of factor XII from anesthesia induction to hypothermia circulation arrest was 42%, whereas the proportion of decline of factor VII during the same period was 20% (P<0.001). Moreover, factor VII recovered to preoperative levels 4 hours after surgery with a relatively faster speed (P<0.001) while factor XII had not recovered (P=0.010). The independent t-test and Wilcoxon test showed that coagulation factor XII levels during hypothermia circulation arrest (P=0.002), total dosage of fibrinogen (P=0.027), total dosage of packed red blood cells (PRBCs) (P=0.006) and total dosage of fresh frozen plasma (FFP) (P=0.022) during the perioperative period were significantly different between the patients who did or did not require reoperation for coagulopathy. Multivariable logistic regression analysis suggested that the factor XII level during hypothermia circulation arrest was an independent risk factor for reoperation for coagulopathy [odds ratio (OR): 1.342, 95% confidence interval (CI): 1.058-1.570; P=0.012].

Conclusions

Factor XII levels are more influenced by surgery and require a longer period of time to recover to preoperative levels compared with factor VII, and the level of factor XII during hypothermia circulation arrest might be an independent risk factor for reoperation for coagulopathy. Therefore, supplementation of coagulation factor XII and its upstream stimulating factors might be a promising therapeutic modality in the future.

A pilot observational study on magnesium and calcium imbalance in elderly patients with acute aortic dissection

Background

Magnesium (Mg) and calcium (Ca) are the principal essential elements involved in endothelial cell homeostasis. Extracellular changes in the levels of either alter endothelial contraction and dilatation. Consequently Mg and Ca imbalance is associated with a high risk of endothelial dysfunction, the main process observed during acute aortic dissection (AAD); in this clinical condition, which mainly affects elderly men, smooth muscle cell alterations lead to intimal tears, creating a false new lumen in the media of the aorta. AAD patients have a high risk of mortality as a result of late diagnosis because often it is not distinguished from other cardiovascular diseases.

We investigated Mg and Ca total circulating levels and the associated pro-inflammatory mediators in elderly AAD patients, to gain further information on the pathophysiology of this disorder, with a view to suggesting newer and earlier potential biomarkers of AAD.

Results

Total circulating Mg and Ca levels were both lower in AAD patients than controls (p < 0.0001). Using Ca as cut-off, 90% of AAD patients with low Ca (<8.4 mg/dL) came into the type A classification of AAD. Stratifying AAD according to this cut-off, Mg was lower in patients with lower total Ca.

Compared to controls, both type A and B AAD patients had higher levels of all the pro-coagulant and pro-inflammatory mediators analyzed, including sP-sel, D-dimer, TNF-α, IL-6, and CRP (p < 0.05). Dividing types A and B using the Stanford classification, no significant differences were found (p > 0.05) The levels of both ICAM-1 and EN-1 were lower in AAD than in a control group (p < 0.0001 and p < 0.05 respectively).

Conclusions

These findings suggest that low Mg and Ca in AAD elderly patients may contribute to altering normal endothelial physiology and also concur in changing the normal concentrations of different mediators involved in vasodilatation and constriction, associated with AAD onset and severity.

Acute phase of aortic dissection: a pilot study on CD40L, MPO, and MMP-1, -2, 9 and TIMP-1 circulating levels in elderly patients

Background

Acute aortic dissection (AAD) is an event which may be rapidly fatal without early diagnosis and treatment. Aging is one of the main risk factors that could leading to AAD. To date, no specific biomarkers are available to increase the speed of diagnosis. CD40 ligand (CD40L), myeloperoxidase (MPO), matrix metalloproteinase (MMP)-1, -2, -9 and metallopeptidase tissue inhibitor 1 (TIMP-1) are biologically related molecules which integrate inflammation, tissue injury and remodeling, all events associated to AAD.

Our is a pilot study to evaluate whether circulating levels of these molecules may be used as potential biomarkers in timely diagnosis of AAD.

Results

Within 24 h of symptom onset, circulating CD40L, MPO, MMP-1,-2,-9 and TIMP-1 were quantified by enzyme-linked immunosorbent assays in 22 patients (40–86 years of age) with AAD of ascending aorta (type A according to Stanford classification) and 11 patients with AAD of descending aorta (type B). 30 healthy individuals age matched were used as control group compared to controls, both type A and B AAD patients had higher CD40L (p < 0.001) and MPO (p < 0.01) levels. MMP-1 was higher in the overall AAD group (p < 0.01). After Stanford classification, type A group had increased level compared to both control and type B (p < 0.01 and p < 0.05, respectively). TIMP-1 was higher in both A and B groups compared to controls (p < 0.001). No differences were observed in MMP-2 and MMP-9 levels.

Conclusions

The simultaneous evaluation of CD40L, MPO and MMP-1 and TIMP-1, which may contribute to structural changes in aortic tissue in AAD patients, seems to be a novel promising diagnostic panel.