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Three Part Question

In [emergency admissions with chest pain], can a [D-dimer test] be used to [rule out Thoracic Aortic Aneurysm]?

Clinical Scenario

A 53 year old man attends the emergency department with a 2 hour history of chest pain that may be cardiac. You want to rule out possible acute aortic aneurysm dissection and wonder whether a D-Dimer level can help do this

Search Strategy

Medline, Cochrane and EMBASE
MEDLINE
(exp AORTIC ANEURYSM, THORACIC/ OR "aortic dissection*".ti,ab OR (thora* adj2 "aortic aneurysm*").ti,ab OR (thora* adj2 "aorta aneurysm*").ti,ab OR (chest* adj2 "aortic aneurysm*").ti,ab OR (chest* adj2 "aortic aneurysm*").ti,ab OR "aortic dissection*".ti,ab OR ANEURYSM, DISSECTING/ OR "dissecting aortic aneurysm*".ti,ab OR "dissecting aorta aneurysm*".ti,ab) AND ( "d dimer".ti,ab OR ddimer.ti,ab OR exp FIBRIN FIBRINOGEN DEGRADATION PRODUCTS/) AND (exp TOMOGRAPHY, X-RAY COMPUTED/ OR "CT scan*".ti,ab OR "computed tomograph*".ti,ab)
 
 
EMBASE
(exp THORACIC AORTA ANEURYSM/ OR exp DISSECTING ANEURYSM/ OR (thora* adj2 "aortic aneurysm*").ti,ab OR (chest* adj2 "aortic aneurysm*").ti,ab OR "aortic dissection*".ti,ab OR "dissecting aortic aneurysm*".ti,ab OR (thora* adj2 "aorta aneurysm*").ti,ab OR "dissecting aorta aneurysm*".ti,ab OR "aorta dissection".ti,ab) AND ("d dimer".ti,ab OR ddimer.ti,ab OR exp D DIMER/) AND ( EXP COMPUTER ASSISTED TOMOGRAPHY/ OR "CT scan*".ti,ab OR "computed tomograph*")
[Limit to: English Language and Publication Year 2006-2016]

Search Outcome

151 papers of which 4 were of sufficient quality. Results already reviewed in these meta-analyses were not presented below.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Wilson S 2016 USA	220 patients (average age 56)	Retrospective cohort study of all patients who had a D-Dimer and CTA performed specifically for acute aortic dissection.	Positive d-dimer in 60.0% cases. Positive D-Dimer carried a sensitivity of 100% (95% CI 15.8-100%) and specificity of 40.4% (95% CI 33.8-47.2%)		Retrospective analysis
Watanabe H 2016 Japan	833 subjects and 1994 non-acute aortic dissection	Meta-analysis with bivariate model methodology. 22 studies. 12 included in analysis	Based on a cutoff value of 500 ng/ml, sensitivity was 0.952 (95% CI 0.901-0.978) and specificity was 0.079 (95% CI 0.036-0.172) D-dimer <500 ng/ml largely decreases possibility of acute aortic dissection.		Based on studies that used univariate analysis and had a high risk of bias.
Satoh 2011 Japan	49 patients	Single centre prospective observational study	10% of patients with acute aortic dissection in emergency settings showed negative D-Dimer test results.		Single centre, observational study
Baez A 2016 UK	349 patients	Meta-analysis of 11 studies - multi centre, multinational.	An aortic dissection detection risk score combined with D-dimer testing is suitable for ruling out aortic dissection in low-intermediate risk patients. Negative likelihood ratio of 0.24% for low risk, 3.4% for intermediate risk and 7.9% for high risk.		Intrinsic weakness of selected studies and hypothetical mathematical model used. No significant difference between D-Dimer testing with CT for the rule out of low risk patients.

Comment(s)

The recent meta-analysis by Watanabe is a well written paper that incorporates most of the latest studies looking at the diagnostic accuracy of D-dimer for acute aortic syndrome. They identified 22 papers and used 12 of these which utilised the cutoff value of 500 ng/ml. The authors analyse and critique the key papers they used in the meta-analysis and this is a strength of their publication. The recent publication by Armado Baez in the Journal of Critical Care, aimed to design a simple, systematic tool for screening patients for aortic dissection utilising D-dimers. Patients are grouped into low, intermediate and high risk. This study was good in showing this score with D-Dimer testing could be used to rule out acute aortic dissection in low risk patients.

Clinical Bottom Line

Patients with low clinical probability for acute aortic dissection and a low D-Dimer are unlikely to have an acute aortic dissection.

References

1. Wilson S, Kinni H, Smoot T et al Overutilization of computed tomography angiography for acute aortic dissection: Identifying additional need for a reliable screening biomarker. Acad Emerg Med 2016; 23:1553-2712
2. Watanabe H Nobuyuki H, Shibata Y et al. Diagnostic test accuracy of D-dimer for acute aortic syndrome: systematic review and meta-analysis of 22 studies with 5000 subjects. Sci. Rep 2016;6, 26893; doi; 10.1038/srep26893
3. Satoh Y, Suzuki M, Shiroshita-Takeshita A et al. Negative D-dimer test for acute aortic dissection. Circulation 2011; 124 (21): 0009-7322 Abstract 252 Circulation. 2011;124:A252, published online before print Dec
4. Baez A, Cochon L. Improved Rule-Out Diagnostic Gain with a Combined Aortic Dissection Detection Risk Score and D-Dimer Bayesian Decision Support Scheme. J. Crit. Care Article in press. Accessed 31/08/2016 doi: http://dx.doi.org/10.1016/j.jcrc.2016.08.007