Impact of Non-Diameter Aortic Indices on Surgical Eligibility: Results from the TITAN: SvS Randomized Controlled Trial

OBJECTIVES

Traditional criteria for intervention on an asymptomatic ascending aortic aneurysm has been a maximal aortic diameter of ⩾5.5cm. The 2022 ACC/AHA aortic guidelines adopted cross-sectional aortic area/height ratio, aortic size index (ASI) and aortic height index (AHI) as alternate parameters for surgical intervention. The objective of this study was to evaluate the impact of using these newer indices on patient eligibility for surgical intervention in a prospective, multicenter cohort with moderate sized ascending aortic aneurysms between 5.0-5.4 cm.

METHODS

Patients enrolled from 2018 to 2023 in the randomization or registry arms of the multicenter trial, TITAN: SvS, were included in the study. Clinical data was captured prospectively in an online database. Imaging data were derived from a core CT lab.

RESULTS

Among the 329 included patients, 20% were female. Mean age was 65.0 ± 11.6 years and mean maximal aortic diameter was 50.8 ±3.9 mm. In the one third of all patients (n=109) who met any one of the three criteria (i.e., ASI ⩾ 3.08 cm/m2, AHI ⩾ 3.21 cm/m or cross-sectional aortic area/height ⩾ 10 cm2/m), their mean maximal aortic diameter was 52.5 ±0.52 mm. Alternate criteria were most commonly met in females compared to males: 20% versus 2% for ASI (p<0.001), 39% versus 5% for AHI (p<0.001) and 39% versus 21% for cross-sectional aortic area/height (p=0.002), respectively.

CONCLUSIONS

One third of patients in Titan:SvS would meet criteria for surgical intervention based on novel parameters vs. the classic definition of diameter⩾5.5cm. Surgical thresholds for ASI, AHI or cross-sectional aortic area/height ratio are more likely to be met in female patients compared to male patients.

Acute Type A Aortic Dissection in Adolescents and Young Adults under 30 Years of Age: Demographics, Etiology and Postoperative Outcomes of 139 cases

BACKGROUND

The prevalence and etiology of acute aortic dissection type A in patients ≤30 years is unknown. The aims of this clinical study were to determine the prevalence and potential etiology of acute aortic dissection type A in surgically treated patients ≤30 years and to evaluate the respective postoperative outcomes in this selective group of patients in a large multi-centre study.

METHODS

Retrospective data collection was performed at the 16 participating international aortic institutions. All patients ≤30years at the time of dissection onset were included. The postoperative results were analysed with regard to connective tissue disease.

RESULTS

The overall prevalence of acute aortic dissection type A ≤ 30years was 1.8% (139 out of 7914 patients), including 51(36.7%) patients who were retrospectively diagnosed with connective tissue disease. Cumulative postoperative mortality was 8.6%, 2.2% and 1.4%, respectively. Actuarial survival was 80% at 10 years postoperatively. Non- connective tissue disease patients (n = 88) had a significantly higher incidence of arterial hypertension (46.6%vs.9.8%;p<0.001) while acute aortic dissection type A affected the aortic root (p < 0.001) and arch (p = 0.029) significantly more often in the connective tissue disease group. A positive family history of aortic disease was present in 9.4% of the study cohort(n = 13).

CONCLUSIONS

The prevalence of acute aortic dissection type A in surgically treated patients ≤30 years is less than 2% with connective tissue disease and arterial hypertension as the two most prevalent triggers of acute aortic dissection type A. Open surgery may be performed with good early results and excellent mid- to long-term outcomes.

STratification risk analysis in OPerative management (STOP score) for drug-induced endocarditis

BACKGROUND

The opioid epidemic has seen a drastic increase in the incidence of drug-associated infective endocarditis (IE). No clinical tool exists to predict operative morbidity and mortality in patients undergoing surgery.

METHODS

A multi-institutional database was reviewed between 2011 and 2018. Multivariate logistic regression was fitted in an automated stepwise fashion. The STratification risk analysis in OPerative management of drug-associated IE (STOP) score was constructed. Morbidity was defined as reintubation, prolonged ventilation, pneumonia, renal failure, dialysis, stroke, reoperation for bleeding, and a permanent pacemaker. Cross-validation provided an unbiased estimate of out-of-sample performance.

RESULTS

A total of 1181 patients underwent surgery for drug-associated IE (median age, 39; interquartile range [IQR], 30-54, 386 women [32.7%], 341 reoperations for prosthetic valve endocarditis [28.9%], 316 patients with multivalve disease [26.8%]). Operative morbidity and mortality were 41.1% and 5.9%, respectively. Predictors of morbidity were dialysis (95% confidence interval [CI], 1.16-2.82), emergent intervention (1.83-4.73), multivalve procedure (1.01-1.98), causative organisms other than Streptococcus (1.09-2.02), and type of valve procedure performed [aortic valve procedure (1.07-2.15), mitral valve replacement (1.03-2.05), tricuspid valve replacement (1.21-2.60)]. Predictors of mortality were dialysis (1.29-5.74), active endocarditis (1.32-83), lung disease (1.25-5.43), emergent intervention (1.69-6.60), prosthetic valve endocarditis (1.24-3.69), aortic valve procedure (1.49-5.92) and multivalve disease (1.00-2.95). Variables maximizing explanatory power were translated into a scoring system. Each point increased odds of morbidity and mortality by 22.0% and 22.4% with an accuracy of 94.0% and 94.1%, respectively.

CONCLUSION

Drug-related IE is associated with significant morbidity and mortality. An easily-applied risk stratification score may aid in clinical decision-making.

709. Multidisciplinary Drug Use Endocarditis Team (DUET): Results From an Academic Center Cohort

Background

Guidelines recommend multidisciplinary models for the management of infective endocarditis but have failed to incorporate the unique challenges of treating drug-use associated infective endocarditis (DUA-IE). Given the drug use and overdose epidemic with rising cases of DUA-IE, we created a multidisciplinary Drug Use Endocarditis Team (DUET), which convened monthly case conferences among the specialties involved, including Infectious Diseases, Cardiothoracic Surgery, Cardiology and Addiction Medicine. Objective: To conduct a retrospective cohort study of the patients presented at the DUET conferences from August 2018 to February 2020 to (1) assess clinical and demographic characteristics and (2) describe clinical outcomes.

Methods

A retrospective chart review was conducted to analyze 57 patient cases, including descriptive statistical analyses of demographics, clinical characteristics, and outcomes.

Results

Among our DUET cohort, 43.8% represented isolated right-sided endocarditis, and 84% involved native valve. Methicillin-susceptible Staphylococcus aureus was the most common microorganism isolated. ID was consulted in 94.7% of cases and overall 43.9% completed the planned antimicrobial course. The 7 patients who developed relapse/recurrent IE were initially managed medically, and 5 did not complete the initial antimicrobial course. Formal cardiothoracic surgery consultation was obtained in 57.9% and 24.6% were managed operatively. Of the patients managed operatively, 64.3% completed the antimicrobial course. The rate of antibiotic completion was higher among patients managed operatively but did not reach statistical significance (p=0.08). Formal addiction medicine consultation was obtained in 85.9% of cases, with 63.1% discharged on medications for opioid use disorder (MOUD). The rate of MOUD on discharge was not significantly different between patients managed operatively and non-operatively.

Figure 1: Patient Characteristics

Figure 2: Infection Characteristics

Figure 3: Outcome Analyses

Conclusion

ID is nearly universally involved in the care of patients with DUA-IE, but this patient population requires input from numerous sub-specialties. Multidisciplinary care teams provide a promising framework for DUA-IE to enhance and integrate nuanced decision-making.

Disclosures

Sarah E. Wakeman, MD, Celero Systems (Advisor or Review Panel member)Optum Labs (Grant/Research Support)UpToDate (Other Financial or Material Support, Author)

Large-vessel occlusion stroke after cardiothoracic surgery: Expanding time windows offer new salvage opportunities

OBJECTIVES

Ischemic stroke due to large-vessel occlusion (LVO) is a complication after cardiothoracic surgery (CTS). Recently published endovascular stroke trials have major implications for treating LVO strokes; we evaluated our experience in patients undergoing CTS.

METHODS

Our prospective institutional CTS database was reviewed between July 2013 and April 2018 for ischemic strokes. Patients with LVO were identified and their course and outcomes analyzed.

RESULTS

A total of 5947 patients were reviewed; 148 (2.48%) had a cerebrovascular complication; 92.5% were ischemic. Of these 10.9% had an LVO. Prolonged aortic crossclamp was associated with LVO (odds ratio, 1.012 for every minute of prolonged aortic crossclamp time; confidence interval, 1.001-1.023) and remained significant in patients with ejection fraction >45%; prolonged cardiac bypass time was only associated with LVO in patients with ejection fraction >45% (odds ratio, 1.012 for every minute of prolonged cardiac bypass time; confidence interval, 1.003-1.021). Patients fell into 2 categories: detection of neurologic deficit in the stable postoperative patient or detection of deficit on emergence from anesthesia. Seven patients met criteria for emergent revascularization, with median National Institutes of Health Stroke Scale score 15, and shorter times from last seen well to deficit detection compared with patients not meeting criteria (P = .032). Median National Institutes of Health Stroke Scale day 7 score improved to 5. There was a trend toward better modified Rankin Scale scores at 3 months in patients who underwent thrombectomy.

CONCLUSIONS

LVO complicates a small proportion of patients after CTS and may be more likely with prolonged aortic crossclamp and cardiac bypass times. Both early and late window endovascular stroke treatment has the potential to positively modify the complication profile of CTS. Greater awareness of this treatment option is needed.

Using macrophage activation to augment immunotherapy of established tumours

Background:

Successful immunotherapy will require alteration of the tumour microenvironment and/or decreased immune suppression. Tumour-associated macrophages (TAMs) are one major factor affecting tumour microenvironment. We hypothesised that altering TAM phenotype would augment the efficacy of immunotherapy.

Methods:

We and others have reported that 5,6-Dimethylxanthenone-4-acetic-acid (DMXAA, Vadimezan) has the ability to change TAM phenotypes, inducing a tumour microenvironment conducive to antitumour immune responses. We therefore combined DMXAA with active immunotherapies, and evaluated anti-tumour efficacy, immune cell phenotypes (flow cytometry), and tumour microenvironment (RT–PCR).

Results:

In several different murine models of immunotherapy for lung cancer, DMXAA-induced macrophage activation significantly augmented the therapeutic effects of immunotherapy. By increasing influx of neutrophils and anti-tumour (M1) macrophages to the tumour, DMXAA altered myeloid cell phenotypes, thus changing the intratumoural M2/non-M2 TAM immunoinhibitory ratio. It also altered the tumour microenvironment to be more pro-inflammatory. Modulating macrophages during immunotherapy resulted in increased numbers, activity, and antigen-specificity of intratumoural CD8⁺ T cells. Macrophage depletion reduced the effect of combining immunotherapy with macrophage activation, supporting the importance of TAMs in the combined effect.

Conclusion:

Modulating intratumoural macrophages dramatically augmented the effect of immunotherapy. Our observations suggest that addition of agents that activate TAMs to immunotherapy should be considered in future trials.

Abstract 5600: Macrophage activation and differentiation augment immunotherapy of established mouse lung tumors

Background: An immunosuppressive environment exists within tumors, induced by both cancer and immune cells, that inhibits the effect of cytotoxic T-lymphocytes. 5,6-Dimethylxanthenone-4 acetic acid (DMXAA) is a small flavanoid-like compound, previously shown to have a strong anti-tumor activity in murine models of cancer, and currently being tested in phase 3 trials in humans. We have shown that part of the effect induced by DMXAA as monotherapy is by activating tumor-associated macrophages. Given the ability of DMXAA alone to potentially induce a tumor microenvironment conducive to anti-tumor immune responses, we hypothesized that it would be a useful adjunct to immuno-gene therapy (immunoRx) in lung cancer.

Methods: We injected 18 mg/kg i.p. of DMXAA (Sigma) to tumor-bearing animals and evaluated its impact in three immunoRx models of non-small cell lung cancer (NSCLC): two aimed at an expressed HPV-E7 antigen, using an adenovirus (Ad. E7) or a Listeria (Listeria. E7) vector, and one using an adenovirus expressing Interferon-α. We compared the effect of immunoRx alone to combination treatment on tumor growth and assessed the mechanism of these changes by evaluating cytotoxic T cells, changes in macrophage phenotype, and tumor microenvironment. This was done by real time RT-PCR, flow cytometry, and staining (IHC).

Results: DMXAA markedly augmented the effect of immuno-gene therapy on large (&gt;200 mm3) established NSCLC flank tumors in the three models and two cell lines of NSCLC tested, resulting in cures in 30-40% of mice. We evaluated mechanisms in the Ad. E7 model. There was no significant difference in the subtypes of systemic (Splenic) immunocytes between the two groups. In contrast, DMXAA increased the intra-tumoral influx of neutrophils, macrophages, and CD8+ T-cells compared to the immunoRx group. Furthermore, adding DMXAA to immunoRx decreased the percentage of intra-tumoral M2 (CD206+) macrophages (out of all tumor cells) by 2-fold, while increasing the percentage of M1 macrophages by 2-fold. Although the percentage of CD8+ T-cells was increased in tumors with the combined treatment compared to immunoRx alone, as seen both by flow cytometry and IHC, there was no difference in their activation or E7 antigen-specificity. They were no changes in the influx of T-regulatory cells. Adding DMXAA to immunoRx up-regulated mRNA levels for a host of pro-inflammatory and chemo-attractant cytokines in tumors including TNF-α, IFN-γ, IL-10, CCL-5 and CCL2.

Conclusion: Macrophage activation and differentiation using DMXAA significantly augments the efficacy of immunoRx in established murine NSCLC tumor models by increasing the traffic of immunocytes into the tumors, activating and differentiating macrophages to a more anti-tumor phenotype and creating an immunostimulatory microenvironment. Our data suggests that combining agents like DMXAA with vaccines should be considered in future immunoRx trials.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5600.

The vascular disrupting agent, DMXAA, directly activates dendritic cells through a MyD88-independent mechanism and generates antitumor cytotoxic T lymphocytes

5,6-Di-methylxanthenone-4-acetic acid (DMXAA) is a small molecule in the flavanoid class that has antitumor activity. Although classified as a "vascular disrupting agent," we have recently conducted studies showing that DMXAA has remarkable efficacy in a range of tumors, working primarily as an immune modulator that activates tumor-associated macrophages and induces a subsequent CD8(+) T-cell-mediated response. To more completely analyze the effect of DMXAA on CD8(+) T-cell generation, we treated mice bearing tumors derived from EG7 thymoma cells that express the well-characterized chicken ovalbumin neotumor antigen. Treatment with DMXAA led to cytokine release, tumor cell necrosis, and ultimately reduction in tumor size that was lymphocyte dependent. Within 24 h of administration, we observed dendritic cell activation in tumor-draining lymph nodes (TDLN). This was followed by a rapid and marked increase in the number of tetramer-specific CD8(+) T cells in the spleens of treated animals. In contrast, the vascular disrupting agent combretastatin A4-phosphate, which caused a similar amount of immediate tumor necrosis, did not activate dendritic cells, nor induce an effective antitumor response. Using in vitro systems, we made the observation that DMXAA has the ability to directly activate mouse dendritic cells, as measured by increased expression of costimulatory molecules and proinflammatory cytokine release via a pathway that does not require the Toll-like receptor adaptor molecule MyD88. DMXAA thus has the ability to activate tumor-specific CD8(+) T cells through multiple pathways that include induction of tumor cell death, release of stimulatory cytokines, and direct activation of dendritic cells.