Patient referral for elective coronary angiography: challenging the current strategy

Patient referral for elective coronary angiography: challenging the current strategy M. Santos, A. Ferreira, A. P. Sousa, J. Brito, R. Calé, L. Raposo, P. Gonçalves, R. Teles, M. Almeida, M. Mendes Cardiology Department Hospital Santa Cruz, Lisbon, Portugal European Society of Cardiology Congress 2011 Controversial issues in patients with stable ischaemic heart disease

CONFLICTS OF INTEREST

BACKGROUND - The evaluation of patients with suspected coronary artery disease (CAD) is based on clinical assessment, often supplemented by noninvasive tests. - Invasive coronary angiography (ICA) is the gold-standard for the diagnosis of CAD but has a relatively high cost, limited availability and a small but real risk of complications. - Despite the frequent use of noninvasive testing, a significant proportion of patients undergoing ICA do not have obstructive CAD.

PURPOSE - To assess the current patterns of noninvasive testing and appraise their diagnostic yield in symptomatic patients undergoing elective invasive coronary angiography for suspected CAD.

METHODS - Observational, cross sectional, prospective study performed at a single hospital centre serving an urban population of 402.000 inhabitants in Lisbon, Portugal. -Study population: the totality of patients referred for ICA evaluation of chest pain symptoms suspected of stable CAD between January 2006 and November 2010.

METHODS - Exclusion criteria: - acute coronary syndrome setting - previously known CAD (prior MI, PCI, CABG, or ICA stenosis >50%) - preoperative cardiac surgery evaluation or other motive - presenting symptom other than chest pain - negative result of noninvasive testing

METHODS - Obstructive CAD was defined as a 50% or more reduction in vessel diameter as compared to a nondiseased proximal segment. - Statistical analysis (SPSS Statistics v. 17.0): - Fisher s exact test (categorical data) - t-test (continuous data) - multivariate logistic regression - two-sided P-value less than 0.05 for significance

11523 coronary angiography procedures (2006-2010) 7479 procedures 5014 procedures 2852 procedures 1925 procedures RESULTS ACS setting, n=4044 prior CAD, n=2465 1892 procedures (2006-2010) preop evaluation or other, n=2162 presenting symptom other than chest pain, n=927 negative noninvasive test or incomplete information, n=33

RESULTS Population characteristics n= 1892 Age, years 64 ± 11 Male sex, n (%) 1141 (60.3) Body Mass Index, Kg/m2 28 ± 4 Cardiovascular risk factors, n (%) Hypertension Diabetes Active smoking Hypercholesterolemia 1484 (78.4) 521 (27.5) 215 (11.4) 1310 (69.2)

RESULTS - The overall prevalence of obstructive CAD in coronary angiography was 56.7%.

Patients, n RESULTS - The overall prevalence of obstructive CAD in coronary angiography was 56.7%. 900 600 300 0 351 (18.6%) 323 (17.1%) 351 (21.1%) 820 (43.3%) 3-vessel 2-vessel 1-vessel W/o obstructive CAD

RESULTS - Patients were referred for coronary angiography after previous positive noninvasive testing in 81.8% of cases.

RESULTS - Patients were referred for coronary angiography after previous positive noninvasive testing in 81.8% of cases. Positive noninvasive testing 1548 (81.8%) Treadmill exercise testing 40.6% Stress myocardial SPECT 35.8% Stress echocardiogram 2.9% Coronary CT angiography 2.5% Without previous testing 344 (18.2%)

RESULTS Obstructive CAD (n=1072) Absent obstrutive CAD (n=820) P value Age, years 65.7 ± 10.4 61.7± 11.0 <0.0001 Male sex, n (%) 71.7% 45.4% <0.0001 Body Mass Index, Kg/m2 27.6 ± 3.9 28.0 ± 4.5 0.03 Cardiovascular risk factors, % Hypertension 81.3% 74.6% <0.0001 Diabetes 32.5% 21.1% <0.0001 Active smoking 13.2% 8.9% 0.003 Hypercholesterolemia 71.9% 65.7% 0.004 Previous positive noninvasive testing 83.6% 79.5% 0.026

RESULTS Adjusted odds ratio 95% CI P value Age 1.05 1.04-1.06 <0.001 Male sex 3.45 2.80-4.24 <0.001 Hypertension 1.35 1.05-1.73 0.019 Diabetes 1.66 1.32-2.08 <0.001 Active smoking 1.91 1.36-2.69 <0.001 Hypercholesterolemia 1.30 1.05-1.61 0.017 Positive noninvasive testing 1.40 1.09-1.81 0.010

RESULTS - The proportion of patients with obstructive CAD remained unchanged during the study period, despite an increase in noninvasive testing. 2006 (n=442) 2007 (n=436) 2008 (n=329) 2009 (n=368) 2010 (n=317) P value Obstructive CAD 57.7% 59.6% 53.8% 55.7% 55.2% ns

RESULTS - The proportion of patients with obstructive CAD remained unchanged during the study period, despite an increase in noninvasive testing. 2006 (n=442) 2007 (n=436) 2008 (n=329) 2009 (n=368) 2010 (n=317) P value Obstructive CAD 57.7% 59.6% 53.8% 55.7% 55.2% ns Noninvasive testing 79.0% 79.1% 82.4% 82.3% 88.3% 0.008 Treadmill ECG 38.5% 42.4% 41.6% 38.9% 42.0% Stress SPECT 36.9% 32.1% 35.9% 36.7% 38.5% Stress echo 3.4% 3.4% 3.3% 2.7% 0.9% Coronary CTA 0.2% 1.1% 1.5% 4.1% 6.9%

DISCUSSION - Slightly more than half (58%) the patients undergoing elective coronary angiography for suspected CAD in our population did have obstructive lesions, despite that 4 out of 5 had a positive noninvasive test. - Patel et al reported an overall rate of 41% of patients with obstructive CAD, that varied significantly among different centres (from 23 to 100%). N Engl J Med 2010;362:886-95 J Am Coll Cardiol 2011;58:801 9

DISCUSSION - Positive noninvasive testing was only a mild independent predictor of obstructive CAD in our population (OR 1.40, p=0.01). - Study limitations: - pretest probability of CAD not available; - dichotomized classification of noninvasive tests as positive or negative for obstructive CAD; - the decision to perform non-invasive testing and the type of the test itself were decided by the attending physician s (not randomized).

CONCLUSION These results suggest that the current referral strategy for coronary angiography can be further improved.

c.miguel.santos@gmail.com

BACKUP SLIDE

RESULTS - Noninvasive tests positive predictive value (PPV): n PPV Treadmill exercise testing 768 60.7% Stress myocardial SPECT 678 53.0% Stress echocardiogram 54 59.3% Coronary CT angiography 48 81.3%

RESULTS - Noninvasive tests positive predictive value and adjusted odds ratio: n PPV Odds ratio 95% CI P Treadmill testing 768 60.7% 1.55 1.17-2.06 0.002 Stress SPECT 678 53.0% - - ns Stress echocardiogram 54 59.3% - - ns Coronary CT angio 48 81.3% 4.82 2.19-10.64 <0.001

RESULTS - Multivariable regression for myocardial revascularization (PCI or CABG), which was performed in 46.7% of patients: Adjusted odds ratio 95% CI P value Age 1.03 1.02-1.04 <0.001 Male sex 2.68 2.19-3.27 <0.001 Diabetes 1.59 1.28-1.96 <0.001 Active smoking 1.54 1.12-2.10 0.007 Positive noninvasive testing 1.59 1.24-2.04 <0.001

Guidelines on the management of stable angina pectoris European Society Cardiology 2006 CCTA 98 87 C-MRI 84-89 84 Eur Heart J 2008;29:531-56 Heart 2005;91:1110-17

RESULTS Obstructive CAD (n=1072) Absent obstrutive CAD (n=820) P value Age, years 65.7 ± 10.4 61.7± 11.0 <0.0001 Male sex, n (%) 769 (71.7) 372 (45.4) <0.0001 Body Mass Index, Kg/m2 27.6 ± 3.9 28.0 ± 4.5 0.03 Cardiovascular risk factors, n (%) Hypertension 872 (81.3) 612 (74.6) <0.0001 Diabetes 348 (32.5) 173 (21.1) <0.0001 Active smoking 142 (13.2) 73 (8.9) 0.003 Hypercholesterolemia 771 (71.9) 539 (65.7) 0.004 Previous positive noninvasive testing 896 (83.6) 652 (79.5) 0.026

RESULTS - The proportion of patients with obstructive CAD remained unchanged during the study period, despite an increase in noninvasive testing. 2006 (n=442) 2007 (n=436) 2008 (n=329) 2009 (n=368) 2010 (n=317) P value Obstructive CAD 255 (57.7%) 260 (59.6%) 177 (53.8%) 205 (55.7%) 175 (55.2%) ns Noninvasive testing Treadmill ECG Stress SPECT Stress echo Coronary CTA 349 (79.0%) 38.5% 36.9% 3.4% 0.2% 345 (79.1%) 42.4% 32.1% 3.4% 1.1% 271 (82.4%) 41.6% 35.9% 3.3% 1.5% 303 (82.3%) 38.9% 36.7% 2.7% 4.1% 280 (88.3%) 42.0% 38.5% 0.9% 6.9% 0.008