Recibido el 31-Enero-2019 – ACEPTADO el 07-FEBRERO-2019.
There are no conflicts of interest to disclose.
When facing a patient with non-ST segment elevation acute coronary syndrome (NSTEACS), the dilemma upon admission, before performing coronary angiography, is whether to treat him/her early with dual antiplatelet therapy, before the possibility of a surgical solution and thus increase the risk of bleeding.
Álvaro Etchepare et al , present in their study, a simple alternative to solve this problem, associating two old tools in the management of NSTEACS: the SYNTAX score [2,3] (Synergy Between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery) (http://www.syntaxscore.com)  and high-sensitivity cardiac troponin T (hs-cTnT). See the paper published
The SYNTAX score  quantifies objectively the severity of coronary lesions according to number, location and complexity, on the basis of the SYNTAX trial results , which was initially useful to establish the guidelines for the treatment of multivessel CAD  or left main coronary artery lesions [7,8,9] and it allows choosing the most appropriate revascularization strategy according to the score , which is still current, to the point of being mentioned in the recently published European guidelines for myocardial revascularization, for the treatment of left main coronary artery and multivessel lesions . Besides, this score was the reason for numerous publications showing the strength of the association of this score with the evolution in the short and long term of patients with NSTEACS [12,13,14].
All that was mentioned above could be summarized in the results obtained in the meta-analysis made by Bundhun et al , significant because of the number of studies and patients involved, by considering for its analysis all randomized controlled trials and observational studies published between January 2007 and January 2017, in MEDLINE, EMBASE and the Cochrane database, using for their search the terms “SYNTAX score and percutaneous coronary intervention”, considered the main criterion for the assessment of adverse cardiovascular results. There were 16 studies included, with a total of 19,751 patients (8,589 with a low score vs 11,162 with a high score). The authors showed that in patients with a low SYNTAX score, the rate of cardiovascular events was significantly lower, and consistent in all subgroups. The results of this meta-analysis are a proof that confirms the relevance and validity of the SYNTAX score implementation within the framework of interventionist cardiology, which allows to classify patients to indicate the most appropriate revascularization strategy.
Are these results the same in all age groups? Ormerod, in a study in individuals ≥90 years did not show a significant association between SYNTAX score and hospital mortality ; while Faroux, when evaluating patients ≥85 years with ACS who underwent coronary angiography, concluded that patients with SYNTAX score ≥25 had a worse prognosis in the short term, showing that in elderly patients, the SYNTAX score was significantly related to hospital stay and mortality .
In relation to the association of hs-cTnT and the Syntax score, there are studies linking the value of hs-cTnT to coronary angiography. Eek et al , when evaluating the usefulness of strain echo to predict total occlusions in patients with NSTEACS, reported that the value of fourth-generation TnT assays was significantly greater in patients with total occlusions, with 77% sensitivity and 78% specificity. Similar findings were reported by Baro et al , in a retrospective analysis on 1011 patients with NSTEACS. They noticed that hs-cTnT was a useful marker to predict the presence of total acute occlusions, with significantly higher concentrations than in those who did not present these angiographic findings.
The paper by Etchepare et al , is a retrospective, observational study, where patients were included consecutively, who had a diagnosis of NSTEACS studied by coronary angiography, whose results were related to peak values of hs-cTnT, that were obtained in 2 samples, upon admission and at 3 h, showing that this biomarker allows predicting the complexity of coronary anatomy evaluated by the SYNTAX score, which in turn allows and according to the results, establishing what strategy to follow, the timing of coronary angiography and antiplatelet therapy to indicate. These results are similar to those of other studies published, such as the one by Bath et al , who found a positive relation between the concentration of hs-cTnT and the complexity of coronary angiography, or that by Yamazaki et al , who showed the same correlation between the value of hs-cTnT and the severity of coronary disease.
Other authors, used other biomarkers along with hs-cTnT to establish the same relation with the SYNTAX score. Thus, Altun et al , established the association existing between hs-cTnT, neutrophil/lymphocyte ratio and the SYNTAX score; and Karandeniz et al  related to high-sensitivity C-reactive protein (hs-CRP) upon admission with severity and coronary complexity, leading to the conclusion that the increased levels of hs-CRP upon admission were one of the strong predictors of a high SYNTAX score in patients with ACS.
In the paper by Etchepare A, et al , patients with NSTEACS were included, studied by coronary catheterization, the result of which showed 39.9% of unstable angina and 60.1% of myocardial infarction; and patients with STEACS, cardiac arrest upon admission, tachyarrhythmias and creatinine clearance of less than 30 ml/min estimated by MDRD were logically excluded, as these conditions increase troponin values, and some of them quite markedly. The methodology implemented was exemplary, and it is worth mentioning that the SYNTAX score was made blindly by two experienced cardiologists. An isolated datum to mention in the study was learning the inter-observer variability in this evaluation.
The study is completely original, as there are few data in bibliography evaluating the predictor power of troponin on angiographic lesions. Altun et al, evaluated troponins associated to leukocytes to predict the SYNTAX score with a good correlation in 287 patients with ACS; a study that included individuals with STEACS in ECG ; while in the study by Yamazaki , there were 408 patients with stable CAD.
We should highlight the number of patients included: a total of 1011 patients, from whom a small percentage (8.6%) had a SYNTAX score >32, similar to the study by Altun ; while left main coronary artery lesions (10.3%) and multivessel lesions (1.4%) had higher percentages; a significant point at the time of deciding to perform angioplasty or surgery as revascularization treatment.
These data are extremely interesting and very important, as a high troponin value would prevent the treatment with P2Y12 antiplatelet agents early, when considering the doubt about whether the patient may possibly be suffering a condition that could be solved surgically. If the patient receives dual antiplatelet therapy, the risk of bleeding increases, so the surgery has to be delayed, which has been extensively studied and validated . Also, these high values of hs-cTnT indicate that patients should be immediately studied invasively to assess the management to follow, as this value of hs-cTnT makes them patients in high cardiovascular risk . The guidelines for the management of such patients are properly established and there is more than enough evidence that urgent coronary cineangiography should be conducted .
The values of hs-cTnT were markedly higher in patients with SYNTAX score >32, with 85% sensitivity and 86% of specificity to predict this score. These data support the predictive power of hs-cTnT of other studies [21,22], but with much more statistical significance because of the amount of patients included and the thorough selection of patients performed.
It would have been interesting to evaluate harder endpoints such as cardiovascular events, according to the troponin-SYNTAX score combination, and also evaluate the treatment they received, mainly if it was angioplasty or surgery, to evaluate events as bleeding or death according to the antiplatelet therapy received.
To conclude, the investigation study by Etchepare et al, is a significant contribution due to the predicting contribution of hs-cTnT on the angiographic lesions assessed by the SYNTAX score, the one with more validation to this date. It is also innovative, as the troponin-SYNTAX score combination has not been used in isolation in NSTEACS before, with a potential great impact because of its clinical and therapeutic implications.
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