Table 3. Sensitivity and specificity of possible clinical decision rules based on multivariable analyses of the study data (total patients with chest pain analysed, n = 303; total patients with ACS, n = 32 [10.6%]; total patients with AMI, n = 27 (8.9%])
Clinical judgment GP CDR variant 1 CDR variant 2 CDR variant 3 CDR variant 4 CDR variant 5 a,c
CDR based on...ST-depressions/11///
ST-elevations/11///
Dyspnoea/1111/
Feeling of pressure chest/1111/
Absent lateral chest pain left/1111
Age ≤45.5, ≥68.5 years//////
Male sex//////
Cardiac murmur//////
POCT H-FABP result positive/1/1//
CDR and/or decision characteristicsMaximum score/6543/
Considered negative if...GP did not refer≤1≤1≤1≤1/
Patients with a negative versus positive score191 negative, 112 positive145 negative, 158 positive147 negative, 156 positive157 negative, 146 positive161 negative, 142 positive46 negative, 204 positive
Rule-out characteristicsSens; NPV for ACS [95% CI]Sens 75.0 [56.2 to 87.9]; NPV 95.8 [91.6 to 98.0]Sens 87.5 [70.1 to 95.9]; NPV 97.2 [92.6 to 99.1]Sens 81.2 [63.0 to 92.1]; NPV 95.9 [90.9 to 98.3]Sens 78.1 [60.0 to 90.0]; NPV 95.5 [90.7 to 98.0]Sens 68.8 [49.9 to 83.3]; NPV 93.8 [88.6 to 96.8]Sens 100 [84.5 to 100]; NPV 100 [90.4 to 100]
FNs for ACS, n (% of total)8 (2.6)4 (1.3)6 (2.0)7 (2.3)10 (3.3)0 (0.0)
TNs for ACS, n (% of total)183 (60.4)141 (46.5)141 (46.5)150 (49.5)151 (49.8)46 (18.4)
Sens; NPV for AMI [95% CI]Sens 70.4 [49.7 to 85.5]; NPV 95.8 [91.6 to 98.0]Sens 88.9 [69.7 to 97.1]; NPV 97.9 [93.6 to 99.5]Sens 81.5 [61.3 to 93.0]; NPV 96.6 [91.8 to 98.7]Sens 77.8 [57.3 to 90.6]; NPV 96.2 [91.5 to 98.4]Sens 66.7 [46.0 to 82.8]; NPV 94.4 [89.3 to 97.2]Sens 81.5 [61.3 to 93.0]; NPV 0 [0 to 53.7]
Rule-in characteristicsSpec; PPV for ACS [95% CI]Spec 67.5 [61.6 to 73.0]; PPV 21.4 [14.5 to 30.4]Spec 52.0 [45.9 to 58.1]; PPV 17.7 [12.3 to 24.8]Spec 52.0 [45.9 to 58.1]; PPV 16.7 [11.4 to 23.7]Spec 55.4 [49.2 to 61.3]; PPV 17.1 [11.6 to 24.4]Spec 55.7 [49.6 to 61.7]; PPV 15.5 [10.2 to 22.7]Spec 20.6 [15.6 to 26.7]; PPV 13.2 [9.1 to 18.8]
FPs for ACS, n (% of total)88 (29.0)130 (42.9)130 (42.9)121 (39.9)120 (39.6)177 (70.8)
TPs for ACS, n (% of total)24 (7.9)28 (9.2)26 (8.6)25 (8.3)22 (7.3)27 (10.8)
Spec; PPV for AMI [95% CI]Spec 66.3 [60.4 to 71.8]; PPV 17.0 [10.8 to 25.5]Spec 51.4 [45.4 to 57.5]; PPV 15.2 [10.2 to 22.0]Spec 51.4 [45.4 to 57.5]; PPV 14.1 [9.2 to 20.8]Spec 54.7 (48.6 to 60.7]; PPV 14.4 [9.3 to 21.4]Spec 55.1 (49.0 to 61.0]; PPV 12.7 [7.9 to 19.6]Spec 0.0 (0.0 to 2.1]; PPV 9.0 [5.8 to 13.5]
Rule in or outb Rule in, out ACS. Rule in, out AMIRule in, out ACS. Rule in, out AMIRule in, out ACS. Rule in, out AMIRule in, out ACS. Rule in, out AMINon-decisiveRule out ACS
  • aDenominator in calculations for CDR variant 5 is 250 patients, since CART was initially performed in a subgroup of 53 patients and internally validated in a subgroup of the remaining 250 patients.

  • bA CDR is considered as possibly relevant for rule in when the pre-test probability (based on the prevalence in the study population) of presence of an AMI (8.9%), or ACS (10.6%), is below the lower margin of the 95% CI of the PPV of the CDR. A CDR is considered as potentially relevant for rule-out when the pre-test probability of absence of an AMI (91.1%), or ACS (89.4%), is below the lower margin of the 95% CI of the NPV.

  • cIn addition to the predicting signs and symptoms derived from CART for ACS, two other symptoms were added to CDR variant 5 for AMI: systolic blood pressure ≥149 mmHg and bradycardia (heart rate <60/min), based on the CART analysis with AMI as an outcome.

  • ACS = acute coronary syndrome. AMI = acute myocardial infarction. CI = confidence interval. FNs = false negatives. FPs = false positives. H-FABP = heart-type fatty acid-binding protein. NPV = negative predictive value. NSTEMI = non-ST elevated myocardial infarction. POCT = point of care test. PPV = positive predictive value. Sens = sensitivity. Spec = specificity. SBP = systolic blood pressure. TNs = true negatives. TPs = true positives.