Daily Cardiology Research Analysis
Analyzed 213 papers and selected 3 impactful papers.
Summary
Three impactful studies stood out today: a nationwide U.S. analysis quantified race- and ethnicity-specific delays in ischemic stroke arrival and EMS activation, a mechanistic study revealed a critical post–myocardial infarction window that markedly enhances AAV-based cardiac gene transfer, and a UK Biobank cohort identified frailty as an independent risk factor for abdominal aortic aneurysm with synergy to genetic risk. Together, they inform health policy, translational timing for gene therapy, and preventive vascular risk stratification.
Research Themes
- Health systems and equity in acute cerebrovascular care
- Timing to optimize cardiac gene therapy after myocardial infarction
- Frailty and genetics in vascular disease risk stratification
Selected Articles
1. Race- and Ethnicity-Specific Hospital Arrival and Emergency Medicine Service Activation Times by US State for Ischemic Stroke.
In a 691,689-patient national registry analysis, Asian, Black, and Hispanic patients had higher adjusted odds of arriving >4.5 hours after stroke onset than White patients, whereas EMS transport intervals were shorter for non-White groups. Marked state-by-race disparities suggest both culturally tailored public education and state-level system improvements are needed to reduce prehospital delays.
Impact: This is an exceptionally large, contemporary, state-resolved analysis quantifying race/ethnicity-specific prehospital delays in ischemic stroke, providing actionable targets for EMS policy and community interventions.
Clinical Implications: Implement culturally tailored stroke awareness campaigns and refine state EMS triage/protocols to reduce onset-to-call and onset-to-arrival delays, especially in states with outlier performance.
Key Findings
- Among 691,689 ischemic stroke patients, adjusted odds of onset-to-arrival >4.5 hours were higher for Asian (OR 1.24), Black (OR 1.18), and Hispanic (OR 1.10) patients versus White patients.
- Black patients had higher odds of onset-to-911 call >2.5 hours (OR 1.21), while 911 call-to-arrival >1 hour odds were lower in Asian (OR 0.55), Black (OR 0.67), and Hispanic (OR 0.69) patients.
- Compared with Texas, 20 states had higher odds of delayed arrival for non-White patients and 9 states for White patients, indicating substantial state-level disparities.
Methodological Strengths
- Very large, contemporary national registry sample with multivariable adjustment for patient and hospital characteristics
- State-level resolution enabling policy-relevant geographic comparisons
Limitations
- Observational cross-sectional design precludes causal inference
- Limited to Get With The Guidelines-Stroke hospitals; generalizability to non-participating hospitals may be constrained
- Potential misclassification of symptom onset times and residual confounding
Future Directions: Prospective implementation studies testing culturally tailored education and state-level EMS protocol changes, with process and outcome metrics (onset-to-call, arrival times, thrombolysis eligibility).
BACKGROUND: Delayed hospital arrival after 4.5 hours of stroke onset excludes patients from intravenous thrombolytic therapy. In the United States, prehospital triage is regulated by each state. Understanding race- and ethnicity-specific prehospital delays in each state could guide targeted interventions. METHODS: This cross-sectional study examined adult patients treated at the GWTG (Get With The Guidelines)-Stroke participating hospitals from January 2021 to August 2023 for acute ischemic stroke. The outcomes, including onset-to-arrival >4.5 hours, onset-to-911 call >2.5 hours, and 911 call-to-arrival >1 hour by race and ethnicity and state, were examined using multivariable logistic regression analysis adjusting for patient and hospital-level characteristics. RESULTS: The study included 691 689 patients with a median age of 71 years and 48.6% women. Compared with White patients, risk-adjusted odds of onset-to-arrival >4.5 hours were higher in Asian patients (1.24 [95% CI, 1.20-1.28]), Black patients (1.18 [95% CI, 1.16-1.19]), and Hispanic patients (1.10 [95% CI, 1.07-1.12]); onset-to-911 call >2.5 hours was higher among Black patients (1.21 [95% CI, 1.16-1.26]); and 911 call-to-arrival >1 hour was lower among Asian (0.55 [95% CI, 0.49-0.63]), Black patients (0.67 [95% CI, 0.62-0.72]), and Hispanic patients (0.69 [95% CI, 0.63-0.75]). Relative to Texas, which has the highest racial and ethnic diversity index, the odds of onset-to-arrival >4.5 hours were higher in 20 states for non-White patients and 9 states for White patients. CONCLUSIONS: Delayed hospital arrivals are more prevalent among Asian, Black, and Hispanic patients, but emergency medicine service transportation times are shorter, suggesting the need for culturally tailored community stroke education. A few states have exceedingly high delayed arrival, highlighting an opportunity to improve state-wide stroke readiness and emergency medicine service triage.
2. Myocardial infarction creates a critical time window for AAV-based cardiac gene transfer.
In mice, myocardial infarction markedly enhances AAV cardiac transduction that peaks at day 3 post-MI, driven by local vascular permeabilization and cardiomyocyte metabolic remodeling, independent of vector dose, serotype, or promoter. Exploiting this transient window improved base editing efficiency and therapeutic outcomes in MI models.
Impact: Reveals a disease-conditioned, time-bound window that can be strategically leveraged to enhance cardiac gene therapy—an advance with direct implications for trial design and therapeutic timing.
Clinical Implications: Suggests aligning AAV-based therapeutics shortly after MI (around day 3) may maximize myocardial transduction and efficacy; informs timing in future clinical translation, while emphasizing the need to validate in humans.
Key Findings
- Myocardial infarction enhanced cardiac AAV transduction with a peak at day 3 post-MI in mice.
- Border-zone AAV enrichment was driven by local vascular permeabilization and cardiomyocyte metabolic remodeling, independent of AAV dose, serotype, or promoter.
- Leveraging the time window improved cardiac base editing and therapeutic outcomes in MI models.
Methodological Strengths
- Mechanistic dissection across multiple AAV variables (dose, serotype, promoter) with consistent findings
- In vivo functional validation showing improved base editing and therapeutic benefit
Limitations
- Findings are in murine MI models; human translatability and timing may differ
- Heterogeneity of MI pathophysiology and comorbidities not captured in controlled models
Future Directions: Validate the timing window in large-animal MI models and develop clinical protocols aligning vector delivery with peak transduction; assess safety and efficacy in early-phase trials.
Approaches to enhance adeno-associated virus (AAV)-based cardiac gene transfer are the key to successful cardiac gene therapy, but factors influencing AAV transduction remain poorly investigated. This study showed that myocardial infarction (MI) enhanced cardiac AAV transduction, peaking at the third day post-MI in mice. The excessive AAV enrichment at the border zone is due to local vascular permeabilization and cardiomyocyte metabolic remodeling, which is independent of AAV dosage, serotypes and promoters. This effect was harnessed to boost cardiac base editing and improve the outcome of gene therapy for MI in mice. Thus, heart disease itself is a non-negligible factor that alters AAV-based cardiac gene transfer, which provides a new inroad to develop approaches to enhance cardiac gene therapy.
3. Frailty, genetic susceptibility, and the risk of abdominal aortic aneurysm: Evidence from the UK Biobank cohort study.
In 410,606 UK Biobank participants followed for a median 12.56 years, both pre-frailty and frailty were associated with significantly higher AAA risk across frailty phenotype and index measures, independent of polygenic risk. Frail individuals with high genetic susceptibility had the greatest hazard, indicating a synergistic effect.
Impact: Identifies frailty as an independent, longitudinal risk factor for AAA and demonstrates synergy with genetic susceptibility, advancing risk stratification beyond traditional factors.
Clinical Implications: Incorporate frailty assessment (phenotype or index) into AAA risk stratification and surveillance decisions, particularly in individuals with elevated genetic risk.
Key Findings
- Pre-frailty and frailty were associated with higher AAA risk versus non-frail: phenotype HRs 1.28 and 1.82; frailty index HRs 1.43 and 2.03.
- Associations persisted after adjusting for polygenic risk and across subgroups.
- Greatest AAA hazard observed in frail participants with high genetic susceptibility, indicating a synergistic effect.
Methodological Strengths
- Very large prospective cohort (N=410,606) with long follow-up (median 12.56 years)
- Dual frailty measures (phenotype and index) and adjustment for polygenic risk with consistent findings
Limitations
- Observational design; residual confounding cannot be excluded
- UK Biobank volunteer bias may limit generalizability to broader populations
Future Directions: Evaluate whether frailty-informed AAA screening strategies improve outcomes and cost-effectiveness; investigate mechanisms linking frailty to aneurysm biology.
BACKGROUND AND AIMS: Despite the frequent co-occurrence of frailty and abdominal aortic aneurysm (AAA), it remains unclear whether frailty is a risk factor for the development of AAA. This study aims to determine the association. METHODS: The study recruited a large-scale cohort from the UK Biobank. The baseline frailty level was assessed through frailty phenotype and frailty index, categorizing participants as non-frail, pre-frail, or frail. The primary outcome was incidence of AAA during follow-up. Cox proportional hazards model was used to explore the association of frailty with AAA risk. The genetic susceptibility was assessed by polygenic risk score. RESULTS: A total of 410,606 participants were enrolled in this study. Over a median follow-up of 12.56 years, AAA developed in 692(0.3%), 931(0.5%), and 180(1.0%) participants categorized as non-frail, pre-frail, and frail respectively under the frailty phenotype, while the frailty index revealed 626(0.3%), 873(0.6%), and 304(1.1%) cases across corresponding frailty strata. Compared with the non-frail participants, the risk of AAA was significantly elevated in pre-frail participants (frailty phenotype: HR = 1.28, 95 %CI = 1.16-1.42; frailty index: HR = 1.43, 95 %CI = 1.28-1.59) and frail participants (frailty phenotype: HR = 1.82, 95 % CI = 1.52-2.18; frailty index: HR = 2.03, 95 %CI = 1.74-2.37). The association remained robust in further adjustment of genetic susceptibility and subgroup analysis. Using non-frail participants with low genetic susceptibility as the reference group, those frail participants with high genetic susceptibility demonstrated the greatest hazard for incident AAA, underscoring their synergistic effect on AAA. CONCLUSIONS: Frailty was longitudinally associated with a high long-term risk of AAA, suggesting frailty as a new independent risk factor for AAA.