The impact of circulating total homocysteine levels on long-term cardiovascular mortality in patients with acute coronary syndromes

Prognostic implications of obstructive sleep apnea in patients with acute coronary syndrome stratified by homocysteine level: a prospective cohort study

BACKGROUND

Sporadic studies have examined the impact of OSA on ACS patients by homocysteine (Hcy) level. This study attempted to comprehensively evaluate the effects of the interaction between Hcy and OSA on long-term cardiovascular outcomes in ACS patients.

METHODS

In this prospective, large-scale cohort study, 2160 patients admitted for ACS were recruited to undergo overnight sleep monitoring. OSA was diagnosed when apnea-hypopnea index ≥ 15 events/h. Patients with normohomocysteinemia (NHcy) were defined as having serum Hcy ≤ 15 μmol/L, and the others had hyperhomocysteinemia (HHcy). The primary endpoint was major adverse cerebrocardiovascular event (MACCE), a composite of cardiovascular death, myocardial infarction, stroke, ischemia-driven revascularization and hospitalization for unstable angina and heart failure.

RESULTS

A total of 1553 eligible ACS patients (average age: 56.3 ± 10.5 years) were enrolled, among which 819 (52.7%) had OSA, and 988 (63.6%) were with NHcy. OSA did not significantly affect the level of Hcy. During a median follow-up of 2.9 (1.6, 3.5) years, after adjustment for clinical confounders, OSA was associated with increased risk for MACCE occurrence versus non-OSA ones in ACS patients with NHcy (adjusted hazard ratio [HR] = 1.36, 95% confidence interval [CI] 1.02-1.83, P = 0.039), but not in those with HHcy (adjusted HR = 0.92, 95%CI 0.62-1.36, P = 0.668). There was an absence of interaction between homocysteine level and OSA in relation to MACCE (interaction P = 0.106).

CONCLUSIONS

OSA was independently associated with worse prognosis in ACS patients with NHcy. Our study emphasized the necessity to identify potential presence of OSA in such a population.

TRIAL REGISTRATION

ClinicalTrials.gov; Number: NCT03362385; URL: www.

CLINICALTRIALS

gov .

Inflammatory cell response following ST-elevation myocardial infarction treated with primary percutaneous coronary intervention and its impact on cardiovascular outcomes: A systematic review and meta-analysis

BACKGROUND

Inflammatory responses post STEMI may mediate major adverse cardiovascular events (MACE). This is the first systematic review to map leukocyte response following a STEMI and its association with outcomes.

METHODS

We systematically searched EMBASE and Medline for studies of STEMIs undergoing primary PCI. Eligible studies reported leukocytes or its subtype plus either 30-day and/or 1-year MACE. Random effects model for pooled proportions was used to estimate 30-day and 1-year mortality and MACE. Meta-regression was used to estimate the effect of leukocyte counts on cardiovascular outcomes. Publication bias was assessed using Egger's regression-based test. The review was registered with PROSPERO (CRD42019124991).

RESULTS

Of the 3,813 studies meeting the preliminary search criteria, 24 cohort studies were eligible for inclusion, representing 19,074 persons [76.4% male (n = 14,539); mean age 61.6 years]. Leukocytes had a mean of 10.5x10⁹ (SD 4.7) on admission and 11.1x10⁹ (SD 3.3) at day one post STEMI. Neutrophils increased day one post STEMI, while lymphocytes decreased. There was limited data on other leukocyte subtypes and beyond day one. Estimated 30-day and 1-year all-cause mortality were 6.5% (95% CI 4.8-8.2, p <0.001) and 9.7% (95% CI 5.6-13.8, p <0.001), while the estimated 30-day and 1-year MACE were 14.9% (95% CI 5.3-24.4, p < 0.001) and 15.2% (95% CI 7.2-23.2, p < 0.001). The meta-analysis was limited by a high degree of heterogeneity between studies.

CONCLUSIONS

This review highlights the urgent need to better characterise inflammation post STEMI to identify mediators for the persistently high mortality and morbidity associated with STEMI.

Targeting cardiovascular inflammation: next steps in clinical translation

Systemic vascular inflammation plays multiple maladaptive roles which contribute to the progression and destabilization of atherosclerotic cardiovascular disease (ASCVD). These roles include: (i) driving atheroprogression in the clinically stable phase of disease; (ii) inciting atheroma destabilization and precipitating acute coronary syndromes (ACS); and (iii) responding to cardiomyocyte necrosis in myocardial infarction (MI). Despite an evolving understanding of these biologic processes, successful clinical translation into effective therapies has proven challenging. Realizing the promise of targeting inflammation in the prevention and treatment of ASCVD will likely require more individualized approaches, as the degree of inflammation differs among cardiovascular patients. A large body of evidence has accumulated supporting the use of high-sensitivity C-reactive protein (hsCRP) as a clinical measure of inflammation. Appreciating the mechanistic diversity of ACS triggers and the kinetics of hsCRP in MI may resolve purported inconsistencies from prior observational studies. Future clinical trial designs incorporating hsCRP may hold promise to enable individualized approaches. The aim of this Clinical Review is to summarize the current understanding of how inflammation contributes to ASCVD progression, destabilization, and adverse clinical outcomes. We offer forward-looking perspective on what next steps may enable successful clinical translation into effective therapeutic approaches-enabling targeting the right patients with the right therapy at the right time-on the road to more individualized ASCVD care.

Relationship between serum homocysteine levels and long-term outcomes in patients with ST-segment elevation myocardial infarction

BACKGROUND

The mortality of cardiovascular disease is constantly rising, and novel biomarkers help us predict residual risk. This study aimed to evaluate the predictive value of serum homocysteine (HCY) levels on prognosis in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

The 419 consecutive patients with STEMI, treated at one medical center, from March 2010 to December 2015 were retrospectively investigated. Peripheral blood samples were obtained within 24 h of admission and HCY concentrations were measured using an enzymatic cycling assay. The patients were divided into high HCY level (H-HCY) and low HCY level (L-HCY) groups. Short- and long-term outcomes were compared, as were age-based subgroups (patients aged 60 years and younger vs. those older than 60 years). Statistical analyses were mainly conducted by Student t-test, Chi-squared test, logistic regression, and Cox proportional-hazards regression.

RESULTS

The H-HCY group had more males (84.6% vs. 75.4%, P = 0.018), and a lower prevalence of diabetes (20.2% vs. 35.5%, P < 0.001), compared with the L-HCY group. During hospitalization, there were seven mortalities in the L-HCY group and 10 in the H-HCY group (3.3% vs. 4.8%, P = 0.440). During the median follow-up period of 35.8 (26.9-46.1) months, 33 (16.2%) patients in the L-HCY group and 48 (24.2%) in the H-HCY group experienced major adverse cardiovascular and cerebrovascular events (MACCE) (P = 0.120). History of hypertension (hazard ratio [HR]: 1.881, 95% confidence interval [CI]: 1.178-3.005, P = 0.008) and higher Killip class (HR: 1.923, 95% CI: 1.419-2.607, P < 0.001), but not HCY levels (HR: 1.007, 95% CI: 0.987-1.027, P = 0.507), were significantly associated with long-term outcomes. However, the subgroup analysis indicated that in older patients, HCY levels were significantly associated with long-term outcomes (HR: 1.036, 95% CI: 1.011-1.062, P = 0.005).

CONCLUSION

Serum HCY levels did not independently predict in-hospital or long-term outcomes in patients with STEMI; however, among elderly patients with STEMI, this study revealed a risk profile for late outcomes that incorporated HCY level.

Homocysteine is a bystander for ST-segment elevation myocardial infarction: a case-control study

Background

Homocysteine has been long considered a risk factor for atherosclerosis. However, cardiovascular events cannot be reduced through homocysteine lowering by B vitamin supplements. Although several association studies have reported an elevation of serum homocysteine levels in cardiovascular diseases, the relationship of homocysteine with ST-segment elevation myocardial infarction (STEMI) is not well established.

Methods

We prospectively enrolled STEMI patients who were consecutively admitted to an intensive care unit following coronary intervention in a single medical center in Taiwan. Control subjects were individuals who presented to the outpatient or emergency department with acute chest pain but subsequently revealed patent coronary arteries by coronary arteriography. The association between serum homocysteine levels and STEMI was investigated. A culture system using human coronary artery endothelial cells was also established to examine the toxic effects of homocysteine at the cellular level.

Results

Patients with chest pain were divided into two groups. The STEMI group included 56 patients who underwent a primary percutaneous coronary intervention. The control group included 17 subjects with patent coronary arteries. There was no difference in serum homocysteine levels (8.4 ± 2.2 vs. 7.6 ± 1.9 μmol/L, p = 0.142). When stratifying STEMI patients by the Killip classification into higher (Killip III-IV) and lower (Killip I-II) grades, CRP (3.3 ± 4.1 vs. 1.4 ± 2.3 mg/L, p = 0.032), peak creatine kinase (3796 ± 2163 vs. 2305 ± 1822 IU/L, p = 0.023), and SYNTAX scores (20.4 ± 11.1 vs. 14.8 ± 7.6, p = 0.033) were significantly higher in the higher grades, while serum homocysteine levels were similar. Homocysteine was not correlated with WBCs, CRP, or the SYNTAX score in STEMI patients. In a culture system, homocysteine at even a supraphysiological level of 100 μmol/L did not reduce the cell viability of human coronary artery endothelial cells.

Conclusions

Homocysteine was not elevated in STEMI patients regardless of Killip severity, suggesting that homocysteine is a bystander instead of a causative factor of STEMI. Our study therefore supports the current notion that homocysteine-lowering strategies are not essential in preventing cardiovascular disease.