Association of perioperative troponin and atrial fibrillation after coronary artery bypass grafting

Perioperative Cardiac Troponin T and Risk of Postoperative Atrial Fibrillation in Coronary Artery Bypass Graft Surgery

BACKGROUND

Postoperative atrial fibrillation (AF) is a common complication after cardiac surgery. We investigated whether perioperative cardiac troponin T (cTnT) is associated with the risk of AF after coronary artery bypass grafting (CABG).

METHODS

Two thousand four hundred twenty-one patients with isolated CABG were studied. High sensitivity cTnT (hs-cTnT) was assessed before and then at 80 hour and 24 hour after the operation. Logistic regression models were applied to investigate the association of perioperative hs-cTnT with postoperative AF. The ROC curve analysis was applied to determine the optimal cutoff values.

RESULTS

Postoperative AF was occurred in 356 (14.7%) patients. Age (adjusted odds ratio [ORs] 1.087-1.090), male gender (OR 1.390), left atrium size (ORs 1.055-1.111), on-pump coronary bypass (OR 1.561), and application of intra-aortic balloon pump (ORs 2.890-2.966) were independently associated with AF. Preoperative hs-cTnT was associated with AF in patients with off-pump coronary bypass (ORs 1.997-2.375). However, the area under the curve for preoperative hs-cTnT was 0.625 in this group. On-pump coronary bypass had major influence on postoperative hs-cTnT levels regardless of the occurrence of AF.

CONCLUSIONS

Preoperative hs-cTnT level is associated with the risk of AF after isolated CABG in patients undergoing off-pump coronary bypass, but the accuracy of this biomarker is yet inadequate. Postoperative levels of hs-cTnT have no predictive value considering large influence by the surgical technique and the cardiac surgery itself. Therefore, perioperative hs-cTnT is not a clinically useful biomarker for predicting AF following CABG.

Perioperative risk factors for new-onset postoperative atrial fibrillation after coronary artery bypass grafting: a systematic review

Background

Postoperative atrial fibrillation (POAF) is the most common cardiac dysrhythmia to occur after coronary artery bypass grafting (CABG). However, the risk factors for new-onset POAF after CABG during the perioperative period have yet to be clearly defined. Accordingly, the aim of our systematic review was to evaluate the perioperative predictors of new-onset POAF after isolated CABG.

Method

Our review methods adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline. We searched seven electronic databases (PubMed, Embase, CINAHL, PsycArticles, Cochrane, Web of Science, and SCOPUS) to identify all relevant English articles published up to January 2020. Identified studies were screened independently by two researchers for selection, according to predefined criteria. The Newcastle–Ottawa Scale was used to evaluate the quality of studies retained.

Results

After screening, nine studies were retained for analysis, including 4798 patients, of whom 1555 (32.4%) experienced new-onset POAF after CABG. The incidence rate of new-onset POAF ranged between 17.3% and 47.4%. The following risk factors were identified: old age (p < 0.001), a high preoperative serum creatinine level (p = 0.001), a low preoperative hemoglobin level (p = 0.007), a low left ventricle ejection fraction in Asian patients (p = 0.001), essential hypertension (p < 0.001), chronic obstructive pulmonary disease (p = 0.010), renal failure (p = 0.009), cardiopulmonary bypass use (p = 0.002), perfusion time (p = 0.017), postoperative use of inotropes (p < 0.001), postoperative renal failure (p = 0.001), and re-operation (p = 0.005). All studies included in the analysis were of good quality.

Conclusions

The risk factors identified in our review could be used to improve monitoring of at-risk patients for early detection and treatment of new-onset POAF after CABG, reducing the risk of other complications and negative clinical outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02224-x.

Atrial fibrillation: is there a role for cardiac troponin?

Atrial fibrillation (AF) is the most common sustained arrhythmia, and its prevalence rate is expected to be doubled over the next decades. Despite the wide use of biomarkers in the management of different cardiac diseases such as myocardial infarction and heart failure, utilization of biomarkers in AF management is not routinely recommended by current guidelines. There is also growing evidence that higher levels of cardiac-specific troponin, as an intracellular protein involved in cardiomyocyte contraction, may be associated with the risk of incident and recurrent AF and its complications. In the present paper, we review the association between troponin and AF and propose clinical suggestions for use of troponin in the management of AF patients.

Biomarkers of Atrial Fibrillation: Which One Is a True Marker?

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmias and associated with the risk of stroke and death. Continuous development of the diagnostic tool and prognostic stratification may lead to optimal management of AF. The use of biomarkers in the management of AF has been grown as an interesting topic. However, the AF biomarkers are not yet well established in the major guidelines. Among these biomarkers, a lot of data show troponin and brain natriuretic peptides are promising for the prediction of future events. The troponin elevation in AF patients may not necessarily be diagnosed as myocardial infarction or significant coronary artery stenosis, and brain natriuretic peptide elevation may not necessarily confirm heart failure. Troponin T and troponin I may predict postoperative AF. Furthermore, troponin and brain natriuretic peptide gave better prognostic performance when compared with the risk score available today.

Activation of complement factor B contributes to murine and human myocardial ischemia/reperfusion injury

The pathophysiology of myocardial injury that results from cardiac ischemia and reperfusion (I/R) is incompletely understood. Experimental evidence from murine models indicates that innate immune mechanisms including complement activation via the classical and lectin pathways are crucial. Whether factor B (fB), a component of the alternative complement pathway required for amplification of complement cascade activation, participates in the pathophysiology of myocardial I/R injury has not been addressed. We induced regional myocardial I/R injury by transient coronary ligation in WT C57BL/6 mice, a manipulation that resulted in marked myocardial necrosis associated with activation of fB protein and myocardial deposition of C3 activation products. In contrast, in fB-/- mice, the same procedure resulted in significantly reduced myocardial necrosis (% ventricular tissue necrotic; fB-/- mice, 20 ± 4%; WT mice, 45 ± 3%; P < 0.05) and diminished deposition of C3 activation products in the myocardial tissue (fB-/- mice, 0 ± 0%; WT mice, 31 ± 6%; P<0.05). Reconstitution of fB-/- mice with WT serum followed by cardiac I/R restored the myocardial necrosis and activated C3 deposition in the myocardium. In translational human studies we measured levels of activated fB (Bb) in intracoronary blood samples obtained during cardio-pulmonary bypass surgery before and after aortic cross clamping (AXCL), during which global heart ischemia was induced. Intracoronary Bb increased immediately after AXCL, and the levels were directly correlated with peripheral blood levels of cardiac troponin I, an established biomarker of myocardial necrosis (Spearman coefficient = 0.465, P < 0.01). Taken together, our results support the conclusion that circulating fB is a crucial pathophysiological amplifier of I/R-induced, complement-dependent myocardial necrosis and identify fB as a potential therapeutic target for prevention of human myocardial I/R injury.

Circulating cardiac biomarkers and postoperative atrial fibrillation in the OPERA trial

BACKGROUND

Postoperative atrial fibrillation (POAF) is a common complication after cardiac surgery and predicts increased morbidity and mortality. Identification of patients at high risk of POAF with the help of circulating biomarkers may enable early preventive treatment but data are limited, especially in contemporary surgical patients.

METHODS

Plasma concentrations of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT) were measured at enrollment, on the morning of cardiac surgery, at end surgery, and 2 days postsurgery in 562 patients undergoing cardiac surgery, randomized to perioperative supplementation with oral fish oil or placebo in the Omega-3 Fatty Acids for Prevention of Post-Operative Atrial Fibrillation trial (OPERA). The primary endpoint was incident POAF lasting ≥ 30 s, centrally adjudicated and confirmed electrocardiographically.

RESULTS

Higher levels of NT-proBNP and hs-cTnT before surgery were associated with older age, renal or cardiac dysfunction and EuroSCORE. NT-proBNP peaked on postoperative day 2 (2172 [1238-3758] ng/L, median [Q1-Q3]), while hs-cTnT peaked at the end of surgery (373 [188-660] ng/L). Fish oil supplementation did not alter the time course of the cardiac biomarkers (P > 0.05). Concentrations of NT-proBNP or hs-cTnT, on the morning of surgery, or changes in their level between morning of surgery and postsurgery, were not significantly associated with POAF after adjustment for clinical and surgical characteristics.

CONCLUSION

Among patients undergoing cardiac surgery, NT-proBNP and hs-cTnT are related to clinical and surgical characteristics, have different perioperative time courses but are not independently associated with risk of POAF.

Troponin-I is a predictor of a delayed diagnosis of atrial fibrillation in acute ischemic stroke and transient ischemic attack

BACKGROUND

Prolonged cardiac monitoring detects higher rates of atrial fibrillation (AF) in ischemic stroke and transient ischemic attack (TIA) but is costly and has practical implications. The use of admission troponin-I (TnI) level to identify patients at high risk of delayed AF detection was investigated.

METHODS

Consecutive ischemic stroke and TIA cases presenting to our institute over a 13-month period were identified from the Irish Stroke and TIA Register. Electronic databases and case notes were examined. "Delayed" AF was diagnosed after a sinus rhythm admission electrocardiogram and no documented history. Group comparisons were made by AF status. The association between TnI and AF was investigated using a multivariate regression model.

RESULTS

A total of 185 cases (130 ischemic stroke) were analyzed. Mean age (standard deviation) was 73.3 (13.9) years, 47% female. Sixty-two cases (33.5%) had AF. The first documented presentation of AF was found in 21 cases, on admission electrocardiogram (n = 11) or inpatient telemetry (delayed, n = 10). TnI was higher in those with delayed AF than in those without AF (W = 194; P = .036). A higher proportion of those with an elevated TnI (30%) than those with a normal TnI (6.1%) had delayed diagnosis of AF (χ(2) = 6.41, P = .011). Having an abnormal TnI was a significant independent predictor of delayed AF detection (odds ratio, 5.8; P = .037).

CONCLUSIONS

TnI elevation is associated with a higher likelihood of subsequent AF diagnosis. Identification of these higher risk stroke and TIA cases for more intensive cardiac monitoring may improve stroke secondary prevention practices.