Pathophysiologic mechanism for MYOcarditis in COVID-19 VAccinations ("MYOVAx" Study)

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): NMRC COVID-19 Research Fund

Objective

This is the first prospective cohort study in Singapore to investigate the COVID-19 vaccine-associated myocarditis to understand its pathophysiology.

Introduction

Acute myocarditis and other cardiovascular symptoms have been observed to be associated with the two mRNA-based coronavirus disease 2019 (COVID-19) vaccines—namely Pfizer-BioNTech BNT162b2 and Moderna mRNA-1273)—currently in-use in Singapore. The mechanisms through which myocarditis occurs are unknown, hence our study aims to understand the pathophysiology of myocarditis associated with COVID-19 vaccines.

Methods

Patients with onset of cardiac manifestations were recruited from multiple hospital outpatient clinics between November 2021 and September 2022. Clinical history and physical examination data was collected with blood sample collection, echocardiography, 12-lead electrocardiogram (ECG), coronary angiography and magnetic resonance imaging (MRI) at recruitment and 6-month follow-up. Analysis of biomarkers, genetic, serological and MRI data was conducted.

Results

As of 6 September 2022, a total of 5 patients have been enrolled (4 males, 1 female). The most commonly reported symptoms across all patients were chest pain/discomfort (80%), followed by palpitations (40%). MRI evidence of myocarditis has been detected in 2 (50%) of the male patients, of which both reported two or more symptoms occurring 1-2 days post-vaccination. Both patients have each received at least two doses of either the Pfizer-BioNTech BNT162b2 vaccine or Moderna mRNA-1273 vaccine. Their MRI findings were consistent with myocarditis. On late gadolinium enhancement (LGE) imaging, epicardial enhancement at the basal inferolateral segment and mid-wall enhancement at the apical anterior, lateral and inferior walls were observed in one patient. Patchy, mid-wall LGE in the basal inferior/inferolateral wall was observed in the other patient. No MRI evidence of myocarditis was available for the sole female patient.

Conclusion

While more data is needed to definitively prove the association of the two mRNA-based Pfizer-BioNTech BNT162b2 and Moderna mRNA-1273 COVID-19 vaccines with post-vaccination myocarditis, we believe our findings may support further investigations to enable risk stratification for vaccine-associated myocarditis and identify potential preventative strategies accordingly.

Real-world comparison of intracoronary imaging and fractional flow reserve measurements on outcomes of semi-urgent and elective percutaneous coronary intervention in a multi-ethnic asian population

Funding Acknowledgements

Type of funding sources: None.

Background

Intracoronary imaging and fractional flow reserve measurements (FFR) are helpful in optimisation of percutaneous coronary intervention (PCI) for patients with stable coronary artery disease, but their comparative efficacy is not well described. Furthermore, few studies involve Asian patients in a real-world context.

Purpose

This study aims to compare the use of intracoronary imaging and fractional flow reserve measurements on the outcomes of semi-urgent and elective PCI in a multi-ethnic Asian population.

Methods

This was a retrospective database study of patients who underwent semi-urgent and elective PCI from 1st Jan 2014 to 31st Dec 2015 at a tertiary academic centre. The patients were split into 2 groups – imaging-guided (IG) consisting of intravascular ultrasound guided PCI or optical coherence tomography guided PCI and physiology-guided (PG) which included FFR-guided PCI. Patients who underwent both IG PCI and PG PCI were excluded. Incidence rates of major adverse cardiovascular events (MACE) (Subsequent myocardial infarction, congestive cardiac failure, all-cause mortality) and major adverse cardiovascular and cerebrovascular events (MACCE) (Subsequent myocardial infarction, congestive cardiac failure, stroke or transient ischemic attack and all-cause mortality) were compared between the two groups. One-to-one propensity score matching (PSM) was performed to control for potential bias.

Results

Of 1,732 patients studied, the median age was 61.0 years (IQR 53.0 to 68.0) and 336 were female (19.4%). There were 266 patients (15.4%) in IG and 186 (10.7%) in PG. The patients were followed up for 33 ±37 months. A total of 133 pairs were matched. In the unmatched cohort, there was no statistical difference between the IG and PG group in the incidence of MACE (24.2% vs 15.5%, p= 0.099) and MACCE (26.6% vs 17.7%, p= 0.112). Baseline and procedural characteristics were balanced between the IG and PG groups. In the matched cohort, the incidence rates of MACE (11.3% vs 7.5%, p= 0.383) and MACCE (15.8% vs 12.8%, p=0.596) did not differ significantly between the two groups.

Conclusion

In a real-world multi-ethnic Asian registry of semi-urgent and elective PCI patients, there was no difference in outcomes whether patients underwent the use of intracoronary imaging or fractional flow reserve measurements during PCI.

Association of body mass index with long-term outcomes after elective and semi-urgent percutaneous coronary intervention

Background

While obesity is associated with cardiovascular mortality and morbidity, patients with higher body mass index (BMI) may have better outcomes post-percutaneous coronary intervention (PCI). This “obesity paradox” is controversial and needs clarification.

Purpose

We aimed to investigate the relationship between BMI and outcomes post-PCI in an Asian cohort.

Methods

A retrospective cohort study was performed on consecutive patients who underwent semi-urgent PCI for non-ST elevation myocardial infraction or unstable angina, and elective PCI for stable angina from January 2014 to December 2015 in a tertiary centre. Patients were underweight (BMI <18.5), normal weight (BMI 18.5–22.9), overweight (BMI 23–24.9), pre-obese (BMI 25–29.9) or obese (BMI ≥30), according to the WHO Asian classification. The primary endpoint was all-cause mortality. The secondary outcomes were subsequent events of stroke or transient ischemic attack, myocardial infarction (MI) and congestive cardiac failure (CCF).

Results

1,610 patients were followed up for 3.71 (±0.97) years, 19.7% were female and mean age was 62.1 years (Table 1). BMI showed a U-shaped relationship with the incidence of death (p<0.001), MI (p=0.005), and CCF (p<0.001) (Figure 1A), which was also shown on Kaplan Meier analysis (Figures 1B-E). With reference to normal weight patients on multivariable Cox analysis, overweight (adjusted HR 0.64, 95% CI 0.42–0.97) and pre-obese (adjusted HR 0.55, 95% CI 0.38–0.80) patients had lower mortality. Underweight patients had higher risk (adjusted HR 2.12, 95% CI 1.01–4.46), while pre-obese patients had lower risk of MI (adjusted HR 0.56, 95% CI 0.34–0.92) compared to normal weight patients. Underweight and obese patients had higher risk of CCF (underweight: adjusted HR 3.05, 95% CI 1.45–6.42; obese: adjusted HR 1.86, 95% CI 1.03–3.35) compared to normal weight patients.

Conclusion

Patients at the lower and upper extremes of BMI demonstrated higher risk of mortality, MI and CCF post-PCI.

Funding Acknowledgement

Type of funding sources: None.

Outcomes from the use of computerized neurocognitive testing in a recurrent glioblastoma clinical trial

Assessment of neurocognitive function (NCF) is important in brain tumor clinical trials, however there are varying methodologies available. We used the Cogstate computerized NCF testing battery and the mini-mental state examination (MMSE) to prospectively assess cognition in adult patients with recurrent glioblastoma (GBM) enrolled in the CABARET randomized phase II clinical trial of bevacizumab versus bevacizumab plus carboplatin chemotherapy. We determined completion rates; compared NCF results between trial arms; and assessed baseline NCF as a predictor of survival outcome. 93 of 103 eligible patients completed baseline Cogstate NCF testing. Completion rates were between 60 and 100% across each timepoint, and 38% at disease progression. There was no evidence of difference between arms in time to deterioration in NCF using either test. Prior to disease progression, deterioration on the Cogstate tests was substantially more common (90%) than deterioration on the MMSE (37%), and decline in the Cogstate composite score within the first 8 weeks was associated with shorter overall survival. This testing methodology may be useful when determining net clinical benefit for therapies in patients with recurrent GBM.

P263 Characterisation of patients with acute myocardial infarction complicated by left ventricular thrombus

Funding Acknowledgements

None

Background/Introduction

Left ventricular (LV) thrombus is a widely recognized complication of acute myocardial infarction (AMI).  Limited data are available from South East Asian patients with this post-infarction complication nor on whether patients with non-ST segment elevation myocardial infarction (NSTEMI) or STEMI with associated LV thrombosis exhibit differing clinical characteristics and/or outcomes. Left Ventricular Ejection Fraction (LVEF) ≤ 40% is a recognized predictor of LV thrombus formation, but there is limited data on LV thrombus patients with EF > 40% or in NSTEMI patients.

Purpose

This study aims to investigate and compare the clinical characteristics, treatment and outcomes of post-AMI patients with LV thrombus formation, with a particular emphasis on those with EF ≤ 40% and in NSTEMI patients. 

Methods

Among 5829 consecutive echocardiogram results containing the keyword "thrombus" from August 2006 to September 2017, we identified 289 post-AMI patients with acute LV thrombus formation. Demographics, treatment and outcome measures were analysed.

Results

Cardiovascular risk factors such as dyslipidaemia (54.0%) and hypertension (50.5%) were commonly present in post-AMI patients with LV thrombus. Mean LVEF was 33.0 ± 10.4%. The majority (68.0%) of patients received triple therapy and 59.5% achieved thrombus resolution. NSTEMI patients had greater number of co-morbidities including heart failure (p < 0.01), documented history of  ischaemic heart disease preceding the AMI leading to thrombus formation (p < 0.01) and lower LVEF (28.3 ± 9.3% vs. 34.8 ± 10.3% , p < 0.01) compared with STEMI cases. On multivariate analysis, having a lower EF was a significant independent predictor of stroke (HR 0.96, 95% CI 0.93-1.00, p = 0.03) and all-cause mortality (HR 0.95, 95% CI 0.92-0.99, p < 0.01). The categories of STEMI and NSTEMI did not predict thrombus resolution, stroke events or all-cause mortality after adjustment.

Conclusion(s)

  Post-AMI LV thrombus patients with NSTEMI and STEMI differed in terms of their co-morbidities in their demographics and co-morbidities but it was a lower EF that was associated with an increased risk of stroke and all-cause mortality. Further studies on this topic are required.

P910An Asian perspective on left ventricular outflow tract cut-offs and the resulting discrepancy in severity grading of aortic stenosis

Objectives

Inconsistencies in grading of aortic stenosis (AS) severity have been reported based on measurement of left ventricular outflow tract diameter (LVOTd), but this remains to be studied in an Asian population. We investigated consistency of grading AS severity at various LVOTd, and subsequently postulated alternative cut-offs for more consistent grading of AS severity.

Methods

350 consecutive patients with index echocardiographic diagnosis of severe AS were divided them into three groups based on LVOTd: “small” (<20mm), “average” (20–22mm), “large” (>22mm). In each group, the consistency of flow-dependent (transaortic mean pressure gradient (MG)) and flow-independent parameters (AVA) were used for classification of AS severity.

Results

Of 350 patients, 51.7% had small LVOTd, while 30.8% and 17.5% had average and large LVOTd respectively. Consistent grading by LVOTd based on AVA and MG, was seen in 33.7% of patients with small, 47.6% with average, 57.7% with large LVOTd. When the hypothetical AVA cut-off of 0.9cm2 was used, consistent grading improved to 38.0% in small, 56.5% in average and 70% in large LVOTd. At an AVA cut-off of 0.8cm2, there was further incremental improvement in the small LVOTd group to 54.1% (p<0.05).

Table 1. Consistent grading by LVOTd based on current guidelines Small LVOTd (<20mm, n=181) Average LVOTd (20–22mm, n=108) Large LVOTd (>22mm, n=61) Consistent grading AVA < cut-off MG >40 Consistency (%) Consistent grading AVA < cut-off MG >40 Consistency (%) Consistent grading AVA < cut-off MG >40 Consistency (%) n=61 33.7 n=51 47.6 n=35 57.7 n=69 38 n=61 56.5 n=43 70* n=98 54.1*+ n=70 65.1* n=43 70.8* *p-value <0.05 when compared with AVA cut-off 0.8cm2 for each LVOTd category; +p-value <0.05 when compared with AVA cut-off 0.9cm2 for each LVOTd category.

Figure 1

Conclusion

Current severe AS guidelines are most consistent with those in the large LVOTd group. However, the majority of the study's Asian population is in the small LVOTd group, which is the group most susceptible to discrepancy in AS grading. Improved consistency in echocardiographic grading may be attained with a lower AVA cut-off in this Asian cohort.

P3366Increased left ventricular remodelling index in paradoxical low-flow severe aortic stenosis with preserved left ventricular ejection fraction compared to normal-flow

Background

Left Ventricular Remodelling Index (LVRI) has been demonstrated to be able to reliably discriminate between an athlete's heart and pathological LV remodelling. Patients with paradoxical low-flow severe aortic stenosis (LF AS) despite preserved left ventricular ejection fraction (LVEF) are a distinct group from normal-flow (NF) with poorer prognosis, more concentric hypertrophy and smaller LV cavities.

Purpose

We compared LVRI in LF compared to NF AS and examined clinical outcomes.

Methods

We studied consecutive patients with index echocardiographic diagnosis of severe AS (aortic valve area<1cm2) with preserved LVEF (>50%). LVRI was determined by the ratio of LV mass to the end-diastolic volume.

Results

Of the 450 patients studied, 149 (33.1%) were LF. There were no significant differences in baseline clinical profile of patients between LF and NF. LVRI was significantly higher in patients with LF compared to NF (2.27±0.68 vs 1.85±0.53 g/ml, p<0.001). Patients with high LVRI (>1.56 g/ml) had poorer clinical outcomes in terms of mortality (log-rank 9.18, p=0.002) and admissions for cardiac failure (log-rank 7.61, p=0.006).

Low-flow (n=149) Normal-flow (n=301) Mean difference/Odds Ratio (95% CI) p-value Age (years) 73.5 (±12.8) 71.0 (±13.1) 2.5 (−0.1 to 5.1) 0.053 Body Mass Index (g/m2) 24.6 (±5.6) 24.7 (±5.3) −0.1 (−1.2 to 1.1) 0.877 Gender (male) 49 (32.9%) 125 (41.5%) 0.7 (0.5 to 1.1) 0.076 Hypertension 100 (67.1%) 195 (64.8%) 1.1 (0.7 to 1.7) 0.624 Diabetes 57 (38.3%) 100 (33.2%) 1.2 (0.8 to 1.9) 0.295 Hyperlipidaemia 79 (53.0%) 147 (49.0%) 1.2 (0.8 to 1.7) 0.425 End-diastolic volume (ml) 72.3 (±18.9) 112.6 (±26.3) −40.2 (−44.9 to −35.5) <0.001 Left ventricular ejection fraction (%) 66.0 (±7.9) 67.4 (±7.1) −1.4 (−2.9 to 0.2) 0.077 Left ventricular mass index (g/m2) 99.7 (±33.0) 126.8 (±37.4) −27.2 (−34.8 to −19.6) <0.001 Transaortic mean pressure gradient (mmHg) 32.2 (±17.4) 37.1 (±19.9) −4.9 (−8.6 to −1.1) 0.011 Aortic valve area (cm2) 0.78 (±0.16) 0.79 (±0.17) 0.1 (−0.2 to 0.1) 0.635 Stroke volume index (ml/m2) 28.6 (±5.6) 46.9 (±9.8) −18.3 (−20.0 to −16.6) <0.001 Left ventricular remodelling index (LVRI, g/ml) 2.27 (±0.68) 1.85 (±0.53) 0.42 (0.31 to 0.54) <0.001

LVRI in LF versus NF AS

Conclusion

Pathological LV remodelling as evidenced by increased LVRI was more common in LF compared to NF AS. Patients with increased LVRI also had worse clinical outcomes.

Acknowledgement/Funding

None

Outcomes by treatment modality in elderly patients with localized gastric and esophageal cancer

Background

We aimed to assess current treatment patterns and outcomes in elderly patients with localized gastric and esophageal (ge) cancers.

Methods

This retrospective analysis considered patients 75 years of age or older with ge cancers treated during 2012-2014. Patient demographics and tumour characteristics were collected. Overall survival (os) and disease-free survival were assessed by univariable and multivariable Cox proportional hazards regression, adjusting for demographics. Logistic regression analyses were used to examine factors affecting treatment choices.

Results

The 110 patients in the study cohort had a median age of 81 years (range: 75-99 years). Primary disease sites were esophageal (55%) and gastric (45%). Treatment received included radiation therapy alone (29%), surgery alone (26%), surgery plus perioperative therapy (14%), chemoradiation alone (10%), and supportive care alone (14%). In multivariable analyses, surgery (hazard ratio: 0.48; 95% confidence interval: 0.26 to 0.90; p = 0.02) was the only independent predictor for improved os. Patients with a good Eastern Cooperative Oncology Group performance status (p = 0.008), gastric disease site (p = 0.02), and adenocarcinoma histology (p = 0.01) were more likely to undergo surgery.

Conclusions

At our institution, few patients 75 years of age and older received multimodality therapy for localized ge cancers. Outcomes were better for patients who underwent surgery than for those who did not. To ensure optimal treatment selection, comprehensive geriatric assessment should be considered for patients 75 years of age and older with localized ge cancers.

To trigger apoptosis, Bak exposes its BH3 domain and homodimerizes via BH3:groove interactions

The Bcl-2 relative Bak is thought to drive apoptosis by forming homo-oligomers that permeabilize mitochondria, but how it is activated and oligomerizes is unclear. To clarify these pivotal steps toward apoptosis, we have characterized multiple random loss-of-function Bak mutants and explored the mechanism of Bak conformation change during apoptosis. Single missense mutations located to the alpha helix 2-5 region of Bak, with most altering the BH3 domain or hydrophobic groove (BH1 domain). Loss of function invariably corresponded to impaired ability to oligomerize. An essential early step in Bak activation was shown to be exposure of the BH3 domain, which became reburied in dimers. We demonstrate that oligomerization involves insertion of the BH3 domain of one Bak molecule into the groove of another and may produce symmetric Bak dimers. We conclude that this BH3:groove interaction is essential to nucleate Bak oligomerization, which in turn is required for its proapoptotic function.