High-sensitivity cardiac troponin I after coronary artery bypass grafting for post-operative decision-making

Detectable troponin below the 99th percentile predicts survival in patients undergoing coronary angiography

Background

Cardiac troponin I (cTnI) above the 99th percentile is associated with an increased risk of major adverse events. Patients with detectable cTnI below the 99th percentile are a heterogeneous group with a less well-defined risk profile. The purpose of this study is to investigate the prognostic relevance of detectable cTnI below the 99th percentile in patients undergoing coronary angiography.

Methods

The study included 14,776 consecutive patients (mean age of 65.4 ± 12.7 years, 71.3 % male) from the Essen Coronary Artery Disease (ECAD) registry. Patients with cTnI levels above the 99th percentile and patients with ST-segment elevation acute myocardial infarction were excluded. All-cause mortality was defined as the primary endpoint.

Results

Detectable cTnI below the 99th percentile was present in 2811 (19.0 %) patients, while 11,965 (81.0 %) patients were below detection limit of the employed assay. The mean follow-up was 4.25 ± 3.76 years. All-cause mortality was 20.8 % for patients with detectable cTnI below the 99th percentile and 15.0 % for those without detectable cTnI. In a multivariable Cox regression analysis, detectable cTnI was independently associated with all-cause mortality with a hazard ratio of 1.60 (95 % CI 1.45-1.76; p < 0.001). There was a stepwise relationship with increasing all-cause mortality and tertiles of detectable cTnI levels with hazard ratios of 1.63 (95 % CI 1.39-1.90) for the first tertile to 2.02 (95 % CI 1.74-2.35) for the third tertile.

Conclusions

Detectable cTnI below the 99th percentile is an independent predictor of mortality in patients undergoing coronary angiography with the risk of death growing progressively with increasing troponin levels.

Comparison of Bretschneider HTK and Blood Cardioplegia (4:1): A Prospective Randomized Study

BACKGROUND

We compared the effect of intermittent blood and histidine-tryptophan-ketoglutarate (HTK) solution of Bretschneider on myocardial histopathology and perioperative outcome.

METHODS

Forty adult cardiac surgery patients were grouped into two (n = 20 for each): (1) Intermittent blood cardioplegia (IBC): had repeated cold 4:1 blood cardioplegia and (2) HTK: had a single dose of cold HTK for cardioprotection. Creatine kinase (CK)-MB, Troponin-I (cTn-I), pH, and lactate were studied in coronary sinus blood before and after aortic cross-clamping (AXC) and systemic blood at postoperative 6th, 24th, and 48th hours. Myocardial biopsy was performed before and after AXC for light microscopy. Vacuolation, inflammation, edema, and glycogen were graded semiquantitatively (from 0 to 3). The myocardial apoptotic index was evaluated via the terminal deoxynucleotidyl transferase dUTP nick end labeling.

RESULTS

There were no differences in perioperative clinical outcomes between the groups. The coronary sinus samples after AXC were more acidotic (7.15 ± 0.14 vs. 7.32 ± 0.07, p = 0.001) and revealed higher CK-MB (21.0 ± 12.81 vs. 12.60 ± 11.80, p = 0.008) in HTK compared with IBC. The HTK had significantly a higher amount of erythrocyte suspension intraoperatively compared with IBC (0.21 ± 0.53 vs. 1.68 ± 0.93 U, p = 0.001). Microscopically, myocardial edema was more pronounced in HTK compared with IBC after AXC (2.25 ± 0.91 vs. 1.50 ± 0.04, p = 0.013). While a significant increase in the apoptotic index was seen after AXC in both groups (p = 0.001), no difference was detected between the groups (p = 0.417).

CONCLUSION

IBC and HTK have a similar clinical outcome and protective effect, except for more pronounced myocardial edema and increased need for intraoperative transfusion with HTK.

The effects of volatile anesthetics and propofol in patients undergoing off-pump coronary artery bypass grafting: a systematic review and meta-analysis

Background

Studies investigating the cardioprotective effect of volatile anesthetics on cardiac troponins in off-pump coronary artery bypass grafting (OPCAB) surgery remain controversial. This current study was conducted to systematically evaluate the impact of volatile anesthetics and propofol on patients undergoing OPCAB surgery.

Methods

A computerized search of electronic databases was conducted up to July 21, 2023, to identify relevant studies using appropriate search terms. The primary outcomes of interest were the levels of myocardial injury biomarkers (e.g., cTnI, cTnT), while secondary outcomes included extubation time, length of ICU stay, 30-day mortality, transfusion and thrombosis, and postoperative recovery, which were compared between two anesthesia techniques.

Results

A search of databases produced 14 relevant studies with a combined total of 703 patients. Among them, 355 were allocated to the volatile anesthetics group and 348 to the propofol group. Our study reveals a statistically significant reduction in myocardial injury biomarkers among patients who received volatile anesthetics compared to those who received propofol (P < .001). Subgroup analysis showed that patients using sevoflurane had lower postoperative cardiac troponins levels compared to propofol (P = .01). However, desflurane and isoflurane currently have no significant advantage over propofol (all P > 0.05). There was no significant difference in postoperative mechanical ventilation time, length of ICU stay, and mortality between the two groups (all P > 0.05).

Conclusions

This study suggested that volatile anesthetics, specifically sevoflurane, in adult OPCAB surgery provide a better cardioprotective effect than propofol.

Systematic Review Registration

PROSPERO (CRD42023444277).

Association of High-Sensitivity Cardiac Troponin T With 30-Day and 5-Year Mortality After Cardiac Surgery

BACKGROUND

The relevance of perioperative myocardial injury (PMI) after cardiac surgery for 30-day mortality and long-term survival remains to be determined.

OBJECTIVES

This study assessed the association of PMI after cardiac surgery, reflected by postoperative troponin release, with 30-day mortality and long-term survival after: 1) coronary artery bypass grafting (CABG); 2) isolated aortic valve replacement (AVR) surgery; and 3) all other cardiac surgeries.

METHODS

A consecutive cohort of 8,292 patients undergoing cardiac surgery with serial perioperative high-sensitivity cardiac troponin T (hs-cTnT) measurements was retrospectively analyzed. The relationship between postoperative hs-cTnT release and 30-day mortality or 5-year mortality was analyzed after adjustment with EuroSCORE II using a Cox proportional hazards model. hs-cTnT thresholds for 30-day and 5-year mortality were determined for isolated CABG (32.3%), AVR (14%), and other cardiac surgery (53.8%).

RESULTS

High postoperative hs-cTnT levels were associated with higher 30-day mortality but not 5-year mortality. In CABG, median peak concentration of postoperative hs-cTnT was 1,044 ng/L, in AVR it was 502 ng/L, and in other cardiac surgery it was 1,110 ng/L. hs-cTnT thresholds defining mortality-associated PMI were as follows: for CABG, 2,385 ng/L (170× the upper reference limit of normal in a seemingly healthy population [URL]); for AVR, 568 ng/L (41× URL); and for other cardiac procedures, 1,873 ng/L (134× URL). hs-cTnT levels above the cutoffs resulted in an HR for 30-day mortality for CABG of 12.56 (P < 0.001), for AVR of 4.44 (P = 0.004), and for other cardiac surgery of 3.97 (P < 0.001).

CONCLUSIONS

PMI reflected by perioperative hs-cTnT release is associated with the expected 30-day mortality but not 5-year mortality. Postoperative hs-cTnT cutoffs to identify survival-relevant PMI are higher than suggested in current definitions.

Defining Peri-Operative Myocardial Injury during Cardiac Surgery Using High-Sensitivity Troponin T

OBJECTIVE

Cut-offs for high-sensitivity troponin (hs-Tn) elevations to define prognostically significant peri-operative myocardial injury (PMI) in cardiac surgery is not well-established. We evaluated the associations between peri-operative high-sensitivity troponin T (hs-TnT) elevations and 1-year all-cause mortality in patients undergoing cardiac surgery.

METHODS

The prognostic significance of baseline hs-TnT and various thresholds for post-operative hs-TnT elevation at different time-points on 1-year all-cause mortality following cardiac surgery were assessed after adjusting for baseline hs-TnT and EuroSCORE in a post-hoc analysis of the ERICCA trial.

RESULTS

1206 patients met the inclusion criteria. Baseline elevation in hs-TnT >x1 99th percentile upper reference limit (URL) was significantly associated with 1-year all-cause mortality (adjusted hazard ratio 1.90, 95% confidence interval 1.15-3.13). In the subgroup with normal baseline hs-TnT (n = 517), elevation in hs-TnT at all post-operative time points was associated with higher 1-year mortality, reaching statistical significance for elevations above: ≥100 × URL at 6 h; ≥50 × URL at 12 and 24 h; ≥35 × URL at 48 h; and ≥30 × URL at 72 h post-surgery. Elevation in hs-TnT at 24 h ≥ 50 × URL had the optimal sensitivity and specificity (73% and 75% respectively). When the whole cohort of patients was analysed, including those with abnormal baseline hs-TnT (up to 10 × URL), the same threshold had optimal sensitivity and specificity (66% and 70%).

CONCLUSIONS

Both baseline and post-operative hs-TnT elevations are independently associated with 1-year all-cause mortality in patients undergoing cardiac surgery. The optimal threshold to define a prognostically significant PMI in our study was ≥50 × URL elevation in hs-TnT at 24 h.

Elevated troponin I is associated with a worse long-term prognosis in patients undergoing beating-heart coronary surgery

OBJECTIVES

The impacts of elevated troponin I levels after coronary artery bypass grafting (CABG) on long-term outcomes were investigated.

METHODS

A total of 996 patients who underwent elective isolated CABG for stable or unstable angina were enrolled. Patients were divided into higher and lower groups based on 80th percentile postoperative peak troponin I (ppTnI) levels. The relationship between ppTnI and long-term clinical outcomes was analysed.

RESULTS

The median ppTnI was 1.55 (2.74) ng/ml and was significantly higher in the conventional CABG subgroup than in the beating-heart CABG subgroup: 4.04 (4.71) vs 1.24 (1.99) ng/ml, P < 0.001. The 80th percentile of ppTnI was 3.3 ng/ml in the beating-heart CABG subgroup and 8.9 ng/ml in the conventional CABG subgroup. In the conventional CABG subgroup (n = 150), 10-year overall survival showed no significant difference between the higher (≥8.9 ng/ml) and lower (<8.9 ng/ml) ppTnI groups: 71% (10%) vs 76% (5%), P = 0.316. However, the beating-heart CABG subgroup (n = 846) showed significantly worse 10-year overall survival in the higher ppTnI group (≥3.3 ng/ml) than in the lower ppTnI group (<3.3 ng/ml): 64% (6%) vs 73% (3%), P = 0.010. In the beating-heart CABG subgroup, multivariable analysis showed that ppTnI exceeding the 80th percentile was a risk factor for overall death (hazard ratio: 1.505, 95% confidence interval: 1.019-2.225, P = 0.040).

CONCLUSIONS

Higher ppTnI over the 80th percentile was associated with worse long-term survival in beating-heart CABG, but not in conventional CABG.

Cardiac Troponin I in Patients Undergoing Percutaneous and Surgical Myocardial Revascularization: Comparison of Analytical Methods

The myocardial infarction (MI) types 4a and 5 guidelines recommend cardiac troponin (cTn) diagnostic decision limits of 5 and 10 times the 99th percentile, respectively. Different cTn kits elicit different responses, so the MI diagnosis is still challenging. The study aimed to establish the cutoff values and the accuracy of three different cTnI kits in the diagnosis of post-procedural MI. We analyzed 115 patients with multivessel stable chronic coronary artery disease; 26 underwent percutaneous coronary intervention, and 89 underwent coronary artery bypass graft. Delayed-enhancement magnetic resonance imaging was performed before and after each intervention for definitive MI diagnoses. Two contemporary and one high-sensitivity cTnI immunoassays were used. ROC curves determined the accuracy of each assay. Low accuracy was observed after applying the current guidelines recommendations. The three cTnI assays accuracies improved when adjusted by the new ROC cutoffs, reaching 82% for MI type 5 for all assays, and 78%, 88%, and 87% for MI type 4 for Siemens, Beckman, and Abbott, respectively. The ultrasensitive and contemporary tests’ accuracy for MI types 4a and 5 diagnoses are equivalent when adjusted for these new cutoffs. The hs-cTnI assays had lower accuracy than contemporary tests for MI types 4a and 5 diagnoses.

[Intensive Care in Heart Surgery - is All Now Different?]

With approximately 100000 operations performed in Germany per year, cardiac surgery is among the surgical specialties that require intensive care tratment most frequently. Although all therapeutic aspects of ICU treatment are of high importance among cardiac surgery patients, there is a focus on hemodynamics with the overarching goal of sufficient oxygen delivery. Patients undergoing cardiac surgery are particularily prone to hemodynamic instability and low cardiac output syndrome, potentially culminating into cardiogenic shock. This article presents an overview of essential elements of intensive care medicine in cardiac surgery, paying special attention to hemodynamic monitoring, low cardiac output syndrome, inotropy, cardiac arrhyhmia, perioperative myocardial infarction, and patient blood management.

Cardiac troponin release following coronary artery bypass grafting: mechanisms and clinical implications

The use of biomarkers is undisputed in the diagnosis of primary myocardial infarction (MI), but their value for identifying MI is less well studied in the postoperative phase following coronary artery bypass grafting (CABG). To identify patients with periprocedural MI (PMI), several conflicting definitions of PMI have been proposed, relying either on cardiac troponin (cTn) or the MB isoenzyme of creatine kinase, with or without supporting evidence of ischaemia. However, CABG inherently induces the release of cardiac biomarkers, as reflected by significant cTn concentrations in patients with uncomplicated postoperative courses. Still, the underlying (patho)physiological release mechanisms of cTn are incompletely understood, complicating adequate interpretation of postoperative increases in cTn concentrations. Therefore, the aim of the current review is to present these potential underlying mechanisms of cTn release in general, and following CABG in particular (Graphical Abstract). Based on these mechanisms, dissimilarities in the release of cTnI and cTnT are discussed, with potentially important implications for clinical practice. Consequently, currently proposed cTn biomarker cut-offs by the prevailing definitions of PMI might warrant re-assessment, with differentiation in cut-offs for the separate available assays and surgical strategies. To resolve these issues, future prospective studies are warranted to determine the prognostic influence of biomarker release in general and PMI in particular.

Right coronary artery deformation and injury following tricuspid valve surgery

Background

Due to its close anatomical proximity to the annular plane of the tricuspid valve (TV), the right coronary artery (RCA) is at risk of injury and distortion during surgical and interventional repair. Recently, reversible, non-flow limiting, purse-string like deformations of the RCA following percutaneous TV annuloplasty have been described. In contrast, there are only anecdotal reports on RCA deformation following conventional TV surgery.

Materials and methods

A retrospective analysis of all patients undergoing TV surgery in our hospital between 2009 and 2019 was performed including all patients who received a post-operative coronary angiography (POCA). Angiographic footage was reviewed for RCA affections.

Results

A total of 1,383 patients underwent TV surgery (replacement and repair) for tricuspid regurgitation in our center. TV repair was performed in 1,248 (90.2%) patients and 135 (9.8%) patients underwent isolated TV surgery. Sixty-five patients (4.7%) underwent POCA within 48 h after surgery due to suspected myocardial ischemia, representing the final study population. Mean age was 70.3 ± 11.3 years, 56.3% were female. Mean EuroSCORE II was 9.8 ± 11.6%. Patients with the need for POCA due to suspected myocardial injury suffered from a higher mortality compared to event-free patients over the long-term follow up period (median 2.9 years) regardless of the observed coronary status. RCA affections were observed in 24 (36.9%) patients. A new RCA deformation without flow-impairment or vascular damage was found in 16 (24.6%) of the cases and was managed conservatively. There was no significantly worse outcome observed as compared to patients without RCA affections. Six (9.2%) patients showed an RCA deformation accompanied by subtotal occlusion. A complete RCA-occlusion was observed in 2 (3.1%) patients. Revascularization by percutaneous coronary intervention could be successfully performed in these patients. RCA deformation occurred exclusively after TV repair while no cases were observed after TV replacement.

Conclusion

Right coronary artery deformation without flow-limitation following surgical TV repair is a specific/typical phenomenon which might not impair patients’ outcome and could be managed conservatively in most of the cases. RCA injury indicating further interventional therapy is a rare complication of TV surgery. However, the need for immediate POCA in general appears to be associated with a worsened intermediate-term outcome.