Validation of the NICE CG95 guideline pretest probability algorithm for appropriate use of coronary CTA in chest pain

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1 Validation of the NICE CG95 guideline pretest probability algorithm for appropriate use of coronary CTA in chest pain Poster No.: R-0007 Congress: RANZCR ASM 2013 Type: Authors: Keywords: DOI: Scientific Exhibit J. Neill 1, A. Wesley 1, K. Branch 2, C. Hamilton-Craig 1 ; 1 Brisbane/ AU, 2 Washington/US Cardiac, CT-Angiography, Catheter arteriography, Diagnostic procedure, Cost-effectiveness, Quality assurance /ranzcr2013/R-0007 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply RANZCR's endorsement, sponsorship or recommendation of the third party, information, product or service. RANZCR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold RANZCR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies,.ppt slideshows,.doc documents and any other multimedia files are not available in the pdf version of presentations. Page 1 of 10

2 Purpose The UK NICE clinical guideline 95 Chest Pain of Recent Onset(2010) [1] proposes calculation of pretest risk of significant coronary artery disease (CAD) using a defined algorithm. A suitable investigative strategy for the patient is then suggested according to the pretest estimate of signficant CAD. Coronary CT angiography (CCTA) is primarily recommended for patients with low pretest likelihood of CAD. Patients with intermediate pretest likelihood should be investigated with a functional imaging assessment and those at high pretest likelihood should have a coronary angiogram. Application of this pretest algorithm to indicate appropriate use of CCTA in clinical practice requires further validation. Methods and Materials CCTA referrrals for diagnosis of chest pain were assessed in an Australian quaternary cardiology centre. Pretest probability of CAD using the NICE CG 95 guideline was adjudicated by two cardiologists taking account of age, gender, risk factors and symptomatology (see Figure 1). Page 2 of 10

3 Fig. 1: Percentage of people estimated to have coronary artery disease according to typicality of symptoms*, age, sex and risk factors - NICE CG95 References: The Prince Charles Hospital - Brisbane/AU NICE pretest likelihood of CAD was categorised as follows: "very low" (<10%), "low" (10-29%), "intermediate" (30-60%) and "high" (>60%). CAD on CCTA and invasive angiography (when performed) was categorised as normal (no CAD), mild stenosis (<50% luminal obstruction), moderate stenosis (50-70%) and severe stenosis (>70%). Expected pretest likelihood and CCTA prevalence of significant CAD (stenosis >50%) were compared. Images for this section: Page 3 of 10

4 Fig. 1: Percentage of people estimated to have coronary artery disease according to typicality of symptoms*, age, sex and risk factors - NICE CG95 Page 4 of 10

5 Results The study group (n=128) comprised 69 (54%) males, mean age 55±12 years with 35% from the Emergency Department. Twenty patients (16%) were categorised as "very low" likelihood, 33 (26%) with "low" likelihood, 37 (29%) with "intermediate" and 38 (29%) with a "high" likelihood of significant CAD (see Figure 2). Fig. 2: Pretest likelihood of significant CAD by NICE clinical algorithm References: The Prince Charles Hospital - Brisbane/AU No subjects in the "very low" pretest likelihood category had significant CAD (Figure 3). CCTA prevalence of significant CAD was 10% in the "low" pretest group, 51% in the "intermediate" pretest group and 55% in the "high" pretest group. These percentages are similar to the pretest likelihood estimates. Page 5 of 10

6 Fig. 3: Prevalence of significant CAD by CCTA in each of the pretest likelihood groups References: The Prince Charles Hospital - Brisbane/AU Downstream invasive angiography was performed in 36% (27/57) of subjects and had a high correlation for intermediate or high pretest groups by CAD category and by CCTA. One patient (3%) in the "low" pretest group had severe stenosis on both CTCA and catheterization. In the "intermediate" group, 15 patients (78%) had catheter angiography confirming CTCA findings - 2 mild stenosis, 3 moderate and 10 severe stenosis. In the "high" pretest group 12 (32%) patients proceeded to angiography confirming CTCA - 3 moderate and 9 severe stenosis. Images for this section: Page 6 of 10

7 Fig. 1: Percentage of people estimated to have coronary artery disease according to typicality of symptoms*, age, sex and risk factors - NICE CG95 Page 7 of 10

8 Fig. 2: Pretest likelihood of significant CAD by NICE clinical algorithm Page 8 of 10

9 Fig. 3: Prevalence of significant CAD by CCTA in each of the pretest likelihood groups Page 9 of 10

10 Conclusion CCTA prevalence of significant CAD is similar to the expected clinical pretest likelihood using the NICE chest pain algorithm. Good correlation was demonstrated between CTCA and catheter angiography. Application of the NICE algorithm appears valid for appropriately directing the initial investigative strategy for patients presenting with new onset chest pain. Personal Information References 1. Nice clinical guideline 95. Chest pain of recent onset: assessment and diagnosis of recent onset chest pain or discomfort of suspected cardiac origin. Page 10 of 10