Coronary artery calcium scoring for ruling-out acute coronary syndrome in chest pain CT

Correspondence / American Journal of Emergency Medicine 35 (2017) 15611580 1565

et al. demonstrated that in the case of the normal airway intubation sce- nario, the effectiveness of the two devices is comparable, but in the case of cervical movement restriction – videolaryngoscopy becomes the more indicated technique. This confirms the results obtained by other authors [8]. research efforts continue to focus on additional methods of airway con- trol for trauma patients as well as cardiopulmonary resuscitation patients. Breathing is a very important direction for research, because it translates di- rectly to improving the efficiency of intubation in emergency medicine con- ditions, where paramedics and emergency responders are not always able to seek assistance from an anesthesiologist. The study that Smereka et al. designed was a randomized, crossover manikin trial which is both a limita- tion of this study as well as its strong point. On the one hand, you can not directly transfer the results obtained in simulated situations for intubation in the conditions of real rescue operations. Alternatively, randomized, crossover studies are only possible under simulated conditions as this is the only way to avoid causing the patient any harm and it also allows for the standardization of rescue procedures.

Marek Dabrowski* Agata Dabrowska

Maciej Sip

Department of Rescue and Disaster Medicine, Poznan University of Medical

Sciences, Poland Polish Society of Simulation Medicine, Poland

*Corresponding author at: Department of Rescue and Disaster Medicine, Poznan University of Medical Sciences, 79 Dabrowskiego Str, 60-529

Poznan, Poland.

Patients with acute chest pain are challenging and only a minority ultimately suffer from acute coronary syndrome (ACS) [1], while the diagnosis of myocardial infarction (MI) is missed in a considerable number of patients [2]. Other disease such as pulmonary embolism (PE) and acute aortic syndrome (AAS) may mimic the symptoms of ACS.

chest computed tomography is the reference standard modal- ity for evaluation of PE and AAS. Cardiac CT has shown to improve triage of patients with suspicion of ACS [3]. Triple rule-out CT or more appro- priate, chest pain CT represents a CT protocol covering the entire chest and performed with ECG-gating for simultaneous evaluation of the cor- onary and pulmonary arteries and thoracic aorta [4]. The value of coro- nary artery calcium (CAC) scoring for quantification of coronary calcifications as part of chest pain CT was not investigated so far.

In this IRB-approved retrospective study, we screened 300 patients

with acute chest pain presenting to the ED and who underwent chest pain CT. Patients with ST-segment elevation infarction (STEMI) and those with suspicion of Non-STEMI did not undergo CT but were direct- ly referred to catheter coronary angiography. Hemodynamically unsta- ble patients were excluded. Further exclusion criteria were known

Table 1

Demographic data of patients undergoing chest pain CT (n = 204).

Number of 93 (46%)




erences patients




Age (years) 51.2 +-

62.6 +-

57.5 +-

57.4 +-

b 0.001


Ladny JR, Sierzantowicz R, Kedziora J, Szarpak L. Comparison of direct and optical lar- (mean +- SD) 15.3




yngoscopy during simulated cardiopulmonary resuscitation. Am J Emerg Med 2017; Sex



35:513-4. Male

57 (61%)

83 (75%)



Shravanalakshmi D, Bidkar PU, Narmadalakshmi K, Lata S, Mishra SK, Adinarayanan S.



Comparison of intubation success and glottic visualization using King Vision and C- Female MAC videolaryngoscopes in patients with Cervical spine injuries with cervical immo-

36 (39%)

28 (25%)

3 (11%)





Agatston score = 0

Agatston score N 0

ACS No ACS P-valuesa P-valuesb


bilization: a randomized clinical trial. Surg Neurol Int 2017.

BMI (kg/m2),

27.3 +-

27.2 +-

27.7 +-

27.1 +-



2152-7806.199560 Feb 6;8:19.

(mean +- SD)





Kleine-Brueggeney M, Buttenberg M, Greif R, Nabecker S, Theiler L. Evaluation of three unchannelled videolaryngoscopes and the Macintosh laryngoscope in patients with a simulated difficult airway: a randomised, controlled trial. Anaesthesia 2017 Mar;72(3):370-8.


7 (8%)

14 (13%)

3 (11%)






59 (63%)

79 (71%)








23 (25%)

50 (45%)







Current or former

39 (42%)

61 (55%)








Bielski K, Smereka J, Ladny JR, Szarpak L. A comparison of the Macintosh laryngoscope and blind intubation via I-gel in intubating an entrapped patient: a randomized cross- over manikin study. Am J Emerg Med 2016. 048 Nov 22. pii: S0735-6757(16)30877-4.
  • Sut EY, Gunal S, Yazar MA, Dikmen B. Comparison of effectiveness of intubation by
  • way of Gum elastic bougie and intubating laryngeal mask airway in endotracheal in-

    Positive family

    34 (37%)

    37 (42%)





    tubation of patients with simulated cervical trauma. Rev Bras Anestesiol 2016. http:// Dec 28. pii: S0034-7094(16)30311-7.


    for CAD



    Ladny JR, Bielski K, Szarpak L, Cieciel M, Konski R, Smereka J. Are nurses able to per- form blind intubation? Randomized comparison of I-gel and laryngeal mask airway. Am J Emerg Med 2017;35:786-7.
  • Smereka J, Ladny Jerzy R, Naylor A, Ruetzler K, Szarpak L. C-MAC compared with direct laryngoscopy for intubation in patients with cervical spine immobilization: a
  • TIMI score (low/- intermediate/- high), %

    HEART score


    2.9 +-


    4.1 +-


    5.5 +-


    3.2 +-

    b 0.001

    b 0.001



    manikin trial. Am J Emerg Med 2017;35:1142-6.

    (mean +- SD)





    highly sensitive












    N 0.014

    Agatston score

    0 (0)

    90 (429)


    0 (0)


    [8] Ladny JR, Smereka J, Szarpak L. Comparison of the Trachway video intubating stylet and Macintosh laryngoscope for endotracheal intubation. Preliminary data. Am J Emerg Med 2017;35:574-5.

    (median, IQR)


    Coronary artery calcium scoring for ruling-out

    Calcium volume

    0 (0)

    92 (368)


    0 (0)


    acute coronary syndrome in chest pain CT

    (median, IQR)


    Calcium mass

    0 (0)

    16 (80)


    0 (0)


    (median, IQR)


    Keywords: Acute chest pain Acute coronary syndrome Calcium scoring Computed tomography Aorta

    ACS: Acute Coronary Syndrome; BMI: Body Mass Index; CAD: Coronary Artery Disease; SD: Standard Deviation; TIMI: Thrombolysis In Myocardial Infarction.

    a Comparison of patients with Agatston score N 0 (n = 111) and those with Agatston score = 0 (n = 93).

    b Comparison of patients with clinical diagnosis of ACS (n = 28) and those without (n

    = 176).

    1566 Correspondence / American Journal of Emergency Medicine 35 (2017) 15611580

    Table 2

    Final diagnosis of patients undergoing chest pain CT.





    Chest pain CT protocol without evaluation of





    coronary arteries (n = 115)





    Chest pain CT protocol with evaluation of





    coronary arteries (n = 89)





    coronary artery disease (CAD) (n = 60) and previous MI (n = 35). Ex- aminations with non-available CAC scans were excluded (n = 36). The final study population included 204 patients (Table 1).

    CT consisted of a non-enhanced and contrast-enhanced ECG-gated

    scan according to institutional standard settings. When the indication included the coronary arteries, sublingual nitroglycerin was adminis- tered and ECG-pulsing window was adapted to the heart rate. The CAC score was quantified on non-enhanced CT using the Agatston method [5]. The TIMI risk [6] and HEART Score [7] were calculated for each patient. The clinical endpoint was the final diagnosis based on lab- oratory, ECG and all available imaging tests including catheter coronary angiography within 30 days after index hospitalization.

    149/204 patients (73%) underwent CT for ruling-out two patholo- gies (AAS/PE, ACS/PE, or ACS/AAS); 55/204 patients (27%) underwent CT for ruling-out ACS, PE and AAS. The prevalence of CAD defined as a positive CAC score was 56%. 21/93 patients with a zero CAC score showed a positive high sensitive troponin, of which one patient was di- agnosed with ACS. The diagnosis ACS was adjudicated to 28/204 pa- tients. Twelve patients (9%) were diagnosed with PE and 6 (3%) with AAS (Table 2).

    In the 111 patients with CAC scores N 0, 25 (23%) were diagnosed with ACS whereas in 86 (77%) patients ACS was ruled-out. Of the 93 pa- tients with a zero CAC score, three (3%) were diagnosed with ACS (50, 54, and 50-years-old; 2 males, low and intermediate TIMI score): one with occlusion of septal LAD branches (Fig. 1), one with occlusion of the proximal LAD, and one with occlusion of the proximal RCA.

    The diagnostic performance of the dichotomized CAC score was: ac- curacy 56%, sensitivity 89%, specificity 51%, PPV 23% and NPV 97% (Table 3). The area-under-the-curve (AUC) of CAC for predicting ACS was 0.75, with no reliable cut-off.

    The final logistic regression model included sex (OR 4.9, 95%CI 1.3- 18.7; P = 0.02), dichotomized TIMI risk score (OR 8.0, 95%CI 3.1-20.6; P b 0.01), and dichotomized CAC score (OR 4.6, 95%CI 1.3-16.9; P = 0.02), with a good model fit (P = 0.39).

    Receiver-operating-characteristics (ROC) analysis showed an AUC of

    0.62 (95%CI 0.52-0.72) for sex, 0.75 (95%CI 0.64-0.85) for the dichoto- mized TIMI risk score and 0.7 (95%CI 0.61-0.79) for the dichotomized CAC score. The AUC of sex and TIMI score was 0.78 (95%CI 0.68-0.89); the combined use of the three variables improved the AUC to 0.84 (95%CI 0.75-0.92) (Fig. 2).

    Previous studies reported controversial results regarding the value of CAC in patients presenting with acute chest pain undergoing cardiac CT [8-11]. Our results in patients undergoing chest pain CT for evaluat- ing a broader spectrum of acute chest disease indicate that a zero CAC score had a 97% NPV for excluding ACS, and that a positive CAC score was a significant, independent predictor of ACS.

    Previous literature advocating CAC scoring for ruling-out ACS in car-

    diac CT had a lower prevalence of CAD [8], while other studies disapproving a zero CAC score had a high prevalence [12]. The preva- lence of CAD in our study was intermediate (56%), and chest pain eval- uation included non-Cardiac conditions such as PE and AAS, which might explain the low prevalence of non-calcified plaques and throm- boembolism in our patients.

    As opposed to contrast-enhanced cardiac CT, which is heavily de- pendent on reader experience [13], CAC scoring is easy to perform and

    Fig. 1. Curved multiplanar reformations of the left anterior descending (a) in a 50-year-old female patient with acute Atypical chest pain. The patient underwent chest pain CT for evaluation of AAS and PE; the CAC score was 0. Cardiac MR imaging performed 4 h after the ED visit demonstrates late gadolinium enhancement indicating myocardial infarction in the ventricular septum (b). Catheter coronary angiography demonstrates Filling defects of two septal branches originating from the LAD indicating thromboembolic occlusion (arrows, c).

    fast, can be interpreted rapidly even in the emergency situation, and re- quires no long training. Thus, the CAC score could serve as an option when 24/7 coverage of chest pain CT in the ED is intended. In conclu- sion, in patients presenting undergoing chest pain CT in the ED a zero CAC score has an excellent NPV for ruling-out ACS.

    Correspondence / American Journal of Emergency Medicine 35 (2017) 15611580 1567

    Table 3

    Accuracy of the Agatston score in patients undergoing chest pain CT, subdivided by the indications for CT.

    Sensitivity [95% CI]

    Specificity [95% CI]

    PPV [95% CI]

    NPV [95% CI]

    Accuracy [95% CI]

    Chest pain CT protocol without evaluation of coronary arteries

    91% (10/11)

    57% (59/104)

    18% (10/55)

    98% (59/60)

    60% (69/115)

    (n = 115)






    Chest pain CT protocol with evaluation of coronary arteries (n

    88% (15/17)

    43% (31/72)

    27% (15/56)

    94% (31/33)

    52% (41/89)

    = 89)






    Total (n = 204)

    89% (25/28)

    51% (90/176)

    23% (25/111)

    97% (90/93)

    56% (115/204)






    CI: Confidence Interval; CT: Computed Tomography Angiography; NPV: Negative Predictive Value; PPV: Positive Predictive Value.

    Fig. 2. ROC analysis comparing the accuracy of the variable sex (blue; AUC: 0.62), TIMI risk score (green; AUC: 0.75) and the CAC score (red; AUC: 0.7) for predicting ACS. Combined analysis of sex and TIMI score (orange; AUC: 0.78). Adding the CAC score to sex and TIMI score improved the AUC significantly (black; AUC: 0.84).

    Ricarda Hinzpeter, MD Kai Higashigaito, MD Fabian Morsbach, MD David Benz, MD

    Hatem Alkadhi, MD, MPH, EBCR*

    Institute of Diagnostic and interventional radiology, University Hospital

    Zurich, University of Zurich, Switzerland

    *Corresponding author at: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistr. 100, CH-8091 Zurich,


    E-mail address: [email protected] (H. Alkadhi)

    Robert Manka, MD

    Institute of Diagnostic and Interventional Radiology, University Hospital

    Zurich, University of Zurich, Switzerland Department of Cardiology, University Heart Center Zurich, University of

    Zurich, Switzerland Institute for Biomedical Engineering, University and ETH Zurich,


    Burkhardt Seifert

    Epidemiology, Biostatistics and Prevention Institute, University of Zurich,


    Dagmar I. Keller, MD

    Institute for Emergency Medicine, University Hospital Zurich, University of

    Zurich, Switzerland


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