Impact of low triiodothyronine syndrome on long-term outcomes in patients with myocardial infarction with nonobstructive coronary arteries

Myocardial ischemia in nonobstructive coronary arteries: A review of diagnostic dilemmas, current perspectives, and emerging therapeutic innovations

Myocardial infarction with nonobstructive coronary arteries is a unique presentation of acute coronary syndrome occurring in patients without significant coronary artery disease. Its pathophysiology involves atherosclerotic and nonatherosclerotic mechanisms such as plaque erosion, coronary microvascular dysfunction, vasospasm, spontaneous coronary artery dissection, autoimmune and inflammatory diseases, and myocardial oxygen supply-demand imbalance. A systematic approach to diagnosis is needed due to the diverse range of underlying causes. Cardiac troponins confirm the myocardial injury and coronary angiography rules out significant obstruction. Cardiac magnetic resonance imaging differentiates ischemic from nonischemic causes, and additional investigations, such as intravascular ultrasound, optical coherence tomography, and provocative testing, play a role in identifying the etiology to guide management strategies. Atherosclerotic cases require antiplatelet therapy and statins, vasospastic cases respond to calcium channel blockers, spontaneous coronary artery dissection is typically managed conservatively, and coronary microvascular dysfunction may require vasodilators. Lifestyle modifications and cardiac rehabilitation are essential for improving outcomes. The prognosis of patients experiencing recurrent events despite treatment is uncertain, but long-term outcomes depend on the etiology, highlighting the need for personalized management. Future research should focus on refining diagnostic protocols and identifying optimal therapeutic strategies. Randomized controlled trials are necessary to establish evidence-based treatments for different subtypes of myocardial infarction with nonobstructive coronary arteries.

Correlation Between Free Thyroxine Levels and Mortality in Hypertensive Patients

Objective: To study the link between free thyroxine (FT4) levels and mortality in hypertensive patients. Methods: Utilizing data from the National Health and Nutrition Examination Survey performed in the United States from 2007 to 2012. Results: This study included 3365 adults from the National Health and Nutrition Examination Survey (NHANES) 2007-2012. Weighted Cox regression model, Kaplan-Meier (KM) survival analysis, and restricted cubic spline (RCS) were used to analyze the link between FT4 levels and mortality in hypertensive patients. Furthermore, subgroup analyses and interaction analyses were carried out to evaluate the stability of links between FT4 levels and all-cause mortality across different subgroups of hypertensive patients. In the weighted Cox regression model, after adjusting for all covariates, FT4 levels treated as a continuous variable were positively linked to all-cause mortality in hypertensive patients (HR = 1.08,95% CI: 1.04-1.12, P < .001). When FT4 levels were treated as a categorical variable according to quartiles, the fully adjusted model found that the highest quartile of FT4 posed a greater all-cause mortality risk in hypertensive patients relative to the lowest quartile (HR = 1.47, 95% CI:1.01-2.15, P = .045). Based on the Kaplan-Meier survival curve, all-cause mortality was notably higher in groups Q3 and Q4 relative to FT4 levels in groups Q1 and Q2 (P < .001). The RCS curve revealed that the all-cause mortality in hypertensive patients exhibited a nonlinear increasing trend with rising FT4 levels (P for nonlinear = .033). The results were further validated by subgroup and sensitivity analyses, which confirmed their robustness and reliability. Conclusion: The level of FT4 is strongly linked to the all-cause mortality risk in hypertensive patients.

The long-term prognostic implications of free triiodothyronine to free thyroxine ratio in patients with obstructive sleep apnea and acute coronary syndrome

Objective

Obstructive sleep apnea (OSA) and thyroid dysfunction frequently overlap clinically and are risk factors for cardiovascular disease. The free triiodothyronine to free thyroxine (FT3/FT4) ratio as a novel biomarker of cardiovascular disease prognosis, but the impact of the FT3/FT4 ratio on the prognosis of OSA in patients with acute coronary syndromes (ACS) remains uncertain.

Methods

In this prospective cohort study, 2160 patients with ACS were recruited and underwent portable sleep monitoring at Beijing Anzhen Hospital from June 2015 to January 2020. OSA was diagnosed when apnea-hypopnea index of ≥15 events/h. Patients were further divided into tertiles according to FT3/FT4 ratio. All patients had scheduled follow-up visits at 1, 3, 6, 9 and 12 months after discharge, with subsequent outpatient visits or telephone follow-up visits every 6 months. The primary endpoint was major adverse cardiovascular and cerebrovascular events (MACCE), including cardiovascular death, myocardial infarction (MI), stroke, ischemia-driven revascularization, or hospitalization for unstable angina or heart failure.

Results

Among 1,547 euthyroid patients enrolled (mean age, 56.0 ± 10.5 years), 812 patients (52.5%) had OSA. The FT3/FT4 ratio between OSA and non-OSA patients was not significantly different. During 2.8 (1.4, 3.5) years follow up, the risk of MACCE increased with the decreasing FT3/FT4 tertiles in patients with OSA (tertile3 as reference, tertile2: hazard ratio (HR) 1.26, 95% CI: 0.85-1.86, P = 0.255; tertile1: 1.60, 95% CI 1.11-2.32; P = 0.013). After adjustment for confounders, the lowest FT3/FT4 tertile was still independently associated with an increased risk of MACCE (adjusted HR 1.66, 95% CI 1.11-2.50, P = 0.015).

Conclusion

Lower FT3/FT4 ratio associated with poor prognosis in patients with ACS and OSA.

Predictive value of free triiodothyronine to free thyroxine ratio on contrast-associated acute kidney injury and poor prognosis in euthyroid patients after percutaneous coronary intervention

PURPOSE

The purpose of the study was to explore the predictive value of free triiodothyronine to free thyroxine ratio (FT3/FT4) on contrast-associated acute kidney injury (CA-AKI) and poor prognosis in euthyroid patients after percutaneous coronary intervention (PCI).

METHODS

The present study included 3,116 euthyroid patients who underwent elective PCI. The main outcome was CA-AKI, and the secondary outcome was long-term mortality. All patients were divided into three groups according to the tertiles of FT3/FT4 levels.

RESULTS

During hospitalization, a total of 160 cases (5.1%) of CA-AKI occurred. Restricted cubic spline (RCS) analysis indicated a linear and negative relationship between FT3/FT4 and CA-AKI risk (P for nonlinearity = 0.2621). Besides, the fully-adjusted logistic regression model revealed that patients in tertile 3 (low FT3/FT4 group) had 1.82 times [odds ratio (OR): 1.82, 95% confidence interval (CI): 1.13-3.02, P = 0.016] as high as the risk of CA-AKI than those in tertile 1 (high FT3/FT4 group). Similarly, patients in tertile 3 were observed to have a higher incidence of long-term mortality [fully-adjusted hazard ratio (HR): 1.58, 95% CI: 1.07-2.32, P = 0.021]. Similarly, the Kaplan-Meier curves displayed significant differences in long-term mortality among the three groups (log-rank test, P < 0.001).

CONCLUSION

In euthyroid patients undergoing elective PCI, low levels of FT3/FT4 were independently associated with an increased risk of CA-AKI and long-term mortality. Routine evaluation of FT3/FT4 may aid in risk stratification and guide treatment decisions within this particular patient group.

Low T3 syndrome is associated with 30-day mortality in adult patients with fulminant myocarditis

Background

Fulminant myocarditis (FM) is a critical disease with high early mortality. Low triiodothyronine syndrome (LT3S) was a strong predictor of poor prognosis of critical diseases. This study investigated whether LT3S was associated with 30-day mortality in FM patients.

Methods

Ninety-six FM patients were divided into LT3S (n=39, 40%) and normal free triiodothyronine (FT3) (n=57, 60%) groups based on serum FT3 level. Univariable and multivariable logistic regression analyses were performed to identify independent predictors of 30-day mortality. Kaplan-Meier curve was used to compare 30-day mortality between two groups. Receiver operating characteristic (ROC) curve and decision curve analysis (DCA) were used to assess the value of FT3 level for 30-day mortality prediction.

Results

Compared to normal FT3 group, LT3S group had higher incidence of ventricular arrhythmias, worse hemodynamics, worse cardiac function, more severe kidney impairment, and higher 30-day mortality (48.7% vs. 12.3%, P<0.001). In univariable analysis, LT3S (odds ratio [OR]:6.786, 95% confidence interval [CI]:2.472-18.629, P<0.001) and serum FT3 (OR:0.272, 95%CI:0.139-0.532, P<0.001) were significant strong predictors of 30-day mortality. After adjustment for confounders in multivariable analysis, LT3S (OR:3.409, 95%CI:1.019-11.413, P=0.047) and serum FT3 (OR:0.408, 95%CI:0.199-0.837, P=0.014) remained independent 30-day mortality predictors. The area under the ROC curve of FT3 level was 0.774 (cut-off: 3.58, sensitivity: 88.46%, specificity: 62.86%). In DCA, FT3 level showed good clinical-application value for 30-day mortality prediction.

Conclusion

In FM patients, LT3S could independently predict 30-day mortality. FT3 level was a strong 30-day mortality predictor and a potentially useful risk-stratification biomarker.

Myocardial infarction with non-obstructive coronary arteries: Etiology, diagnosis, treatment and prognosis

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is responsible for 10% of myocardial infarctions. Previously, patients were thought to have good prognosis, but evidence-based management and treatment strategies were scarce. Today, researchers and physicians recognize MINOCA as a condition with non-trivial mortality and morbidity. Therapeutic strategies are highly dependent on the underlying disease mechanism in each patient. However, to reach a diagnosis of MINOCA, a multimodal approach is required and, even with an optimal work-up, the cause remains unknown in 8-25% of patients. Research has been growing and position papers from the European Society of Cardiology (ESC) and the American Heart Association/American College of Cardiology have been published, and MINOCA has been included in the more recent ESC guidelines on myocardial infarction. Nonetheless, some clinicians still assume that the absence of coronary obstruction excludes the possibility of acute myocardial infarction. Therefore, in the present paper, we aim to compile and present the available data on the etiology, diagnosis, treatment, and prognosis of MINOCA.

FT3/FT4 ratio is correlated with all-cause mortality, cardiovascular mortality, and cardiovascular disease risk: NHANES 2007-2012

BACKGROUND

Thyroid hormones play a vital role in maintaining the homeostasis of the cardiovascular system. The FT3/FT4 ratio can be used to evaluate the rate of T4-to-T3 conversion, reflecting the peripheral sensitivity of thyroid hormones. There is no study to investigate its relationship with death and cardiovascular disease (CVD) in the general population.

METHODS

This retrospective cohort study involved 8,018 participants with measured thyroid function and no prior thyroid disease who participated in the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2012. Mortality status was determined by routine follow-up using the National Death Index through December 31, 2015.

RESULTS

During a median of 87 months of follow-up, we observed 699 all-cause deaths, including 116 cardiovascular deaths. In multivariate adjusted models, higher free thyroxine (FT4) was linked to increased all-cause mortality (HR, 1.15 per SD; 95% CI, 1.09-1.22), cardiovascular mortality (HR, 1.18 per SD; 95% CI, 1.01-1.39), and CVD risk (HR, 1.17 per SD; 95% CI, 1.08-1.27). Higher free triiodothyronine (FT3) was linked to decreased all-cause mortality (HR 0.81 per SD; 95% CI, 0.70-0.93). Higher FT3/FT4 ratio was linked to decreased all-cause mortality (HR, 0.77 per SD; 95% CI, 0.69-0.85), cardiovascular mortality (HR, 0.79 per SD; 95% CI, 0.62-1.00), and CVD risk (HR, 0.82 per SD; 95% CI, 0.74-0.92). The FT3/FT4 ratio stratified findings were broadly consistent with the overall results.

CONCLUSIONS

FT3, FT4, and the FT3/FT4 ratio were all independent predictors of all-cause death. FT4 and the FT3/FT4 ratio, but not FT3, were independent predictors of cardiovascular mortality and CVD risk. Along with FT3 and FT4, we should pay equal attention to the FT3/FT4 ratio in the general population.