Daily Cardiology Research Analysis
Analyzed 59 papers and selected 3 impactful papers.
Summary
Three impactful cardiology studies stood out today: (1) age- and sex-specific normal left ventricular longitudinal strain curves with novel diastolic metrics and external prognostic validation; (2) a reconstructed individual patient-level meta-analysis showing Mitral TEER improves survival over medical therapy but is less durable than surgery in functional MR; and (3) a mechanistic study unveiling a cold–microbiota–leucine–Zic2–Gas6–efferocytosis axis driving atherosclerosis and identifying Lactobacillus johnsonii as a potential intervention.
Research Themes
- Standardized cardiac imaging biomarkers and prognostication
- Comparative effectiveness in valvular heart disease interventions
- Microbiome–immunity–metabolism axis in atherosclerosis
Selected Articles
1. Normal standardized left ventricular longitudinal strain curves stratified by age and sex in healthy individuals: The Copenhagen City Heart Study.
Using 1,641 healthy participants, the authors generated sex- and age-specific normal LV longitudinal strain curves and derived novel diastolic metrics (EDS, LDS) plus deviation indexes. External validation in the LOOP study showed that mean strain deviation independently predicted a composite of cardiovascular death, incident heart failure, or atrial fibrillation beyond conventional measures.
Impact: Provides standardized strain references and novel metrics with publicly available code and external prognostic validation, enabling harmonized echo phenotyping and risk stratification.
Clinical Implications: Age/sex-standardized LV strain curves and deviation metrics can refine interpretation of speckle-tracking echocardiography and identify patients at higher risk for cardiovascular events, informing earlier surveillance or intervention.
Key Findings
- Established sex- and age-specific normal LV longitudinal strain curves from 1,641 healthy individuals.
- Derived novel diastolic strain measures (EDS, LDS) capturing age-related morphologic changes; EDS decreased while LDS increased with age.
- In external validation (LOOP; n=1,307; median follow-up 4.9 years), mean strain deviation independently predicted cardiovascular death or incident HF/AF (adjusted HR 1.02, 95% CI 1.00–1.05).
- Normal curves and analysis code were made publicly available, supporting reproducibility and adoption.
Methodological Strengths
- Large derivation cohort with external validation and Cox/C-statistics-based prognostic testing.
- Public release of normal curves and code enhances transparency and reproducibility.
Limitations
- External validation cohort (LOOP) was older, which may affect generalizability to younger populations.
- Incremental prognostic effect size (HR per unit) was modest; further multi-ethnic validation is needed.
Future Directions: Validate diastolic strain metrics across diverse populations and platforms; assess clinical utility for therapy guidance and integration into risk scores.
AIMS: To establish normal sex- and age-specific longitudinal strain curves, to quantify their morphological variation with age, and to demonstrate their utility by deriving novel measures from them with the aim of testing prognostic value. METHODS AND RESULTS: Age- and sex-appropriate normal strain curves were derived from healthy participants of the Copenhagen City Heart Study (CCHS). Four novel measures were constructed: early (EDS) and late (LDS) diastolic strain, primarily to assess age-related variation in strain curve morphology, and mean and diastolic strain deviation. Their prognostic value was assessed using Cox proportional hazards regression and C-statistics internally in the CCHS and externally in the LOOP study against a composite endpoint of cardiovascular death and incident heart failure or atrial fibrillation.In total, 1,641 healthy subjects (mean±SD age 45.3±15.2 years, 62.3% female) from the CCHS and 1,307 (mean±SD age 74.4±4.0 years, 47.4% female) from the LOOP study were included. EDS decreased with age while LDS increased. During a median follow-up of 4.9 [IQI: 3.0, 5.6] years, 409 (31.3%) subjects met the outcome in the LOOP study. Mean strain deviation was independently associated with the outcome (adjusted HR = 1.02 (95% CI: 1.00, 1.05), p = 0.045), while diastolic strain deviation was not. CONCLUSION: We established normal sex- and age-specific longitudinal strain curves and furthermore demonstrated their utility by deriving novel measures from these with prognostic value beyond conventional measures. While promising, further validation in external populations is warranted. The normal curves and relevant code are publicly available.
2. Functional mitral valve regurgitation outcomes by treatment modality: a systematic review and meta-analysis of reconstructed survival data.
Reconstructed individual patient data from 16 studies (n=4,570) show that both MTEER and surgical repair reduce all-cause mortality versus optimized medical therapy in functional MR. However, MTEER is associated with higher late mortality, recurrent MR, and reoperation compared with surgery, while still lowering hospitalizations and MACE compared with medical therapy.
Impact: Provides comparative, time-sensitive outcome estimates across modalities using reconstructed patient-level survival, informing treatment selection when randomized head-to-head data are limited.
Clinical Implications: For suitable surgical candidates, SMVR offers superior durability and survival; MTEER remains valuable for higher-risk or inoperable patients, improving survival and reducing hospitalizations over medical therapy.
Key Findings
- Across up to 60 months, MTEER (HR 0.65) and SMVR (HR 0.39) reduced all-cause mortality versus optimized medical therapy.
- Compared with SMVR, MTEER had higher risks of late mortality (HR 1.68), recurrent MR >2 (HR 3.31), and reoperation (HR 4.62).
- MTEER decreased hospitalization risk by 30% and reduced MACE by 21% versus medical therapy.
- Patients selected for MTEER were older and higher-risk than surgical cohorts, underscoring confounding by indication.
Methodological Strengths
- Reconstructed IPD from Kaplan–Meier curves enabling advanced survival analyses (time-varying Cox, RMST).
- Multiple sensitivity approaches (landmark, time-restricted) to test robustness.
Limitations
- Nonrandomized evidence susceptible to confounding by indication and selection bias.
- Heterogeneity in patient risk, procedural techniques, and definitions across included studies.
Future Directions: Prospective, head-to-head comparative studies with standardized endpoints; risk-modeling to individualize modality choice; durability-focused outcomes and quality-of-life measures.
BACKGROUND: Functional mitral regurgitation (FMR) carries poor prognosis, and optimal management remains debated. Mitral Transcatheter Edge-to-Edge Repair (MTEER) is an alternative to surgical repair (SMVR) or optimized medical therapy (OMT), but long-term outcomes are uncertain. METHODS: PubMed, Embase, Scopus, and the Cochrane Library were searched for studies reporting Kaplan-Meier curves of MTEER, SMVR, or OMT in FMR. Individual patient data (IPD) were reconstructed using the Liu method with accuracy checks. Pooled IPD were analyzed with Cox and time-varying Cox models, landmark, time-restricted, and restricted mean survival time analyses. RESULTS: Sixteen studies (n = 4,570) were included. Patients undergoing MTEER were older and higher risk, with greater prevalence of atrial fibrillation, prior myocardial infarction, chronic kidney disease, higher EuroSCORE, and more frequent NYHA class ≥ III compared with SMVR. Over up to 60 months, both MTEER (HR: 0.65; 95% CI: 0.57-0.75; p < 0.001) and SMVR (HR: 0.39; 95% CI: 0.33-0.46; p < 0.001) significantly reduced all-cause mortality versus OMT, whereas MTEER carried higher mortality risk than SMVR (HR: 1.68; 95% CI: 1.43-1.97; p < 0.001). MTEER was less effective than SMVR in reducing recurrent MR > 2 (HR: 3.31; 95% CI: 1.62-6.75; p < 0.001) and reoperation (HR: 4.62; 95% CI: 2.22-9.61; p < 0.001). In contrast, MTEER reduced hospitalization risk by 30% compared to OMT (HR: 0.70; 95% CI: 0.64-0.77; p < 0.001) and decreased MACE by 21% (HR: 0.79; 95% CI: 0.73-0.84; p < 0.001). CONCLUSIONS: MTEER improves survival and reduces hospitalization and MACE compared with OMT but is less durable than SMVR, with higher risks of recurrent MR, reoperation, and late mortality.
3. Gut microbiota-associated leucine elevation promotes cold-induced atherosclerotic plaque formation and instability.
In ApoE−/− mice, cold exposure reshapes the gut microbiota, elevates circulating leucine, suppresses macrophage Zic2 and Gas6, impairs efferocytosis, and drives plaque growth and instability. Restoring Lactobacillus johnsonii normalized leucine, reactivated Zic2–Gas6 signaling, rescued efferocytosis, and attenuated atherosclerosis, highlighting a modifiable microbiota–metabolite–immune axis.
Impact: Reveals a previously unrecognized mechanistic axis linking environmental cold stress, microbiota-derived leucine, efferocytosis failure, and atherosclerosis, and identifies a tractable probiotic intervention.
Clinical Implications: While preclinical, targeting gut microbial control of systemic leucine (e.g., L. johnsonii supplementation) could emerge as a strategy to mitigate winter surges in atherosclerotic events by enhancing macrophage efferocytosis.
Key Findings
- Cold exposure accelerated plaque growth and instability with gut dysbiosis and altered host metabolism in ApoE−/− mice.
- Cold-associated microbiota elevated circulating leucine; leucine suppressed macrophage Zic2, reduced Gas6, impaired efferocytosis, and increased vascular inflammation.
- Lactobacillus johnsonii supplementation normalized leucine, restored Zic2–Gas6 signaling, rescued efferocytosis, and attenuated atherosclerosis; leucine supplementation mimicked cold effects.
Methodological Strengths
- Integrated multi-omics with fecal microbiota transplantation and mechanistic cell assays.
- Bidirectional validation via probiotic rescue and leucine supplementation experiments.
Limitations
- Findings are from murine models; human translational validation is needed.
- Long-term safety, dose, and durability of probiotic/metabolic interventions remain undefined.
Future Directions: Validate leucine–Zic2–Gas6 axis in human cohorts; test L. johnsonii or leucine-lowering strategies in early-phase clinical trials; explore seasonal cardiovascular risk modulation.
BACKGROUND: Environmental factors such as cold exposure have been increasingly recognized as contributors to atherosclerosis progression, yet the underlying mechanisms linking environmental stress to vascular pathology remain incompletely understood. In particular, the role of the gut microbiota and microbiota-associated metabolites in cold-induced atherosclerosis has not been fully elucidated. METHODS: A cold exposure model was established in ApoE⁻/⁻ mice fed a Western diet. Integrated multi-omics analyses were combined with fecal microbiota transplantation (FMT) and mechanistic cellular assays to investigate gut microbiota remodeling, metabolic alterations, and immune regulation during cold-induced atherosclerosis. RESULTS: In this study, we demonstrate that cold exposure accelerates atherosclerotic plaque growth and instability in parallel with pronounced gut microbiota dysbiosis and alterations in host metabolic profiles. FMT combined with metabolomic analyses showed that cold-associated gut microbiota is closely associated with elevated circulating leucine levels, suggesting that cold-induced microbial remodeling may participate in this process by modulating host systemic leucine availability. Mechanistically, increased leucine suppressed the Zic family member 2 (Zic2) in macrophages, leading to reduced expression of growth arrest-specific 6 (Gas6), a key mediator of efferocytosis. Impaired Gas6-dependent efferocytosis resulted in defective clearance of apoptotic cells, heightened vascular inflammation, and increased plaque instability. Importantly, supplementation with Lactobacillus johnsonii, a commensal bacterium depleted under cold exposure, normalized circulating leucine levels, restored Zic2-Gas6 signaling, enhanced macrophage efferocytosis, and attenuated atherosclerotic plaque progression. Conversely, leucine supplementation recapitulated the effects of cold exposure on plaque development and instability. CONCLUSIONS: Collectively, these findings identify a previously unrecognized cold-microbiota-leucine-Zic2-Gas6-efferocytosis axis that links environmental stress to atherosclerosis progression. Targeting gut microbial regulation of host systemic leucine levels, including L. johnsonii-based interventions, may represent a promising therapeutic strategy for preventing cold-induced atherosclerotic cardiovascular disease.