Referral For Invasive Coronary Angiography Research Articles

False positive results of SPECT - we should minimize the unnecessary referrals to invasive coronary angiography

Purpose: False positive (FP) results are common in single-photon emission computed tomography (SPECT) performed for obstructive coronary artery disease (OCAD) investigation. It is important to discriminate whether an ischemic result of SPECT is a FP, to avoid unnecessary referrals for invasive coronary angiography (ICA). We determined the clinical factors that were independently associated with a FP SPECT result. Methods: We analyzed a cohort of patients referred for ICA for stable coronary artery disease diagnosis, based on clinical judgment and a SPECT positive for ischemia, in a single tertiary-care center (2006-2011). Traditional and nontraditional coronary artery disease risk factors, modified Framingham risk score (FRS), symptoms, pre-test (SPECT) probability of OCAD, left ventricular ejection fraction and ICA results were assessed. OCAD was defined as any luminal narrowing ≥70%, or ≥50% for the left main artery. A FP SPECT was defined as reversible stress-induced perfusion defect and no OCAD. The predictors of a FP result were determined by the chi-square, exact Fisher and t-student tests when appropriate, and multivariate analysis (logistic regression). The discriminatory power for a FP result, of a model based on those predictive factors, was assessed by the area under the ROC curve (AUC) analysis. Results: 960 patients were included: 66.6±9.9 years, 58.1% male, mean 10-year Framingham risk 19.0%; 45.9% typical angina and 17.5% atypical angina; 55% high pre-test probability of OCAD; 13.6% depressed left ventricular ejection fraction (<55%). Globally, 51.0% of SPECT were FP results. The factors independently associated with a FP SPECT were: absence of severe angina (OR 6.1, 95% CI 2.1-17.4), absence of typical angina (OR 4.2, 95% CI 2.9-5.9), presence of atypical angina (OR 2.8, 95% CI 1.6-5.0), normal left ventricular ejection fraction (≥55%) (OR 2.5, 95% CI 1.7-3.5), female gender (OR 2.4, 95% CI 1.8-3.4) and lower FRS (OR 1.2, 95% CI 1.1-1.2), (all p<0.05). A model considering these factors together had good discriminatory power for predicting a FP result: AUC 0.80, 95% CI 0.78-0.83. Conclusions: Half of SPECT were FP in a population of patients referred for ICA following clinical judgment and a SPECT positive for ischemia. When analyzed together, the absence of severe angina/typical angina, the presence of atypical angina, normal left ventricular ejection fraction, female gender and lower FRS have good power for discriminating a FP result. These parameters should be given more relevance in order to avoid some unnecessary referrals for ICA.

False positive results of treadmill exercise ECG - we should minimize the unnecessary referrals to invasive coronary angiography

Purpose: False positive (FP) results are common in treadmill exercise ECG testing (TMT) performed for obstructive coronary artery disease (OCAD) screening. It is important to discriminate whether an ischemic response in TMT is a FP result, to avoid unnecessary referrals for invasive coronary angiography (ICA). We determined the clinical factors that were independently associated with a TMT FP result. Methods: We analyzed a cohort of patients referred for ICA for stable coronary artery disease diagnosis, based on clinical judgment and a TMT positive for ischemia, in a single tertiary-care center (2006-2011). Traditional and nontraditional coronary artery disease risk factors, modified Framingham risk score, symptoms, pre-test (TMT) probability of OCAD, left ventricular ejection fraction and ICA results were assessed. OCAD was defined as any luminal narrowing ≥70%, or ≥50% for the left main artery. A FP TMT result was defined as an ischemic response (2006 TMT European Society of Cardiology guidelines) and no OCAD. The predictors of a FP result were determined by the chi-square, exact Fisher and t-student tests when appropriate, and multivariate analysis (logistic regression). The discriminatory power for a FP result, of a model based on those predictive factors, was assessed by the area under the ROC curve (AUC) analysis. Results: 1243 patients were included: 65.2±9.9 years, 63.0% male, mean 10-year Framingham risk 17.8%; 51.1% typical angina and 20.1% atypical angina; 65.4% high pre-test probability of OCAD; 4.3% depressed left ventricular ejection fraction (<55%). Globally, 51.6% of TMT were FP results. The factors independently associated with a FP TMT were: absence of severe angina (OR 22.0, 95% CI 5.3-91.2), presence of atypical angina (OR 17.3, 95% CI 9.4-31.6), absence of angina (OR 3.8, 95% CI 2.9-5.2), female gender (OR 2.4, 95% CI 1.8-3.3), non-smoking (OR 2.1, 95% CI 1.4-3.0), absence of diabetes (OR 1.5, 95% CI 1.1-2.0) and younger age (OR 1.1, 95% CI 1.0-1.1), (all p<0.05). A model considering these factors together had good discriminatory power for predicting a FP result: AUC 0.80, 95% CI 0.78-0.83. Conclusions: Half of positive TMT were FP in a population of patients referred for ICA following clinical judgment and a TMT positive for ischemia. When analyzed together, the absence of angina/severe angina, the presence of atypical angina, female gender, non-smoking, absence of diabetes and younger age have good power for discriminating a FP result. These parameters should be given more relevance in order to avoid some unnecessary referrals for ICA.

Effect of cardiac hybrid 15O-water PET/CT imaging on downstream referral for invasive coronary angiography and revascularization rate

This study evaluates the impact of hybrid imaging on referral for invasive coronary angiography (ICA) and revascularization rates. A total of 375 patients underwent hybrid (15)O-water positron emission tomography (PET)/computed tomography (CT)-based coronary angiography (CTCA) imaging for the evaluation of coronary artery disease (CAD). Downstream treatment strategy within a 60-day period after hybrid PET/CTCA imaging for ICA referral and revascularization was assessed. CTCA examinations were classified as showing no (obstructive) CAD, equivocal (borderline test result), or obstructive CAD, while the PET perfusion images were classified into normal or abnormal. On the basis of CTCA imaging, 182 (49%) patients displayed no (obstructive) CAD. Only 10 (5%) patients who showed no (obstructive) CAD on CTCA were referred for ICA, which were all negative. An equivocal CT study was observed in 80 (21%) patients, among whom 56 (70%) showed normal myocardial perfusion imaging (MPI), resulting in referral rates for ICA of 18% for normal MPI and 71% for abnormal MPI, respectively. No revascularizations were performed in the presence of normal MPI, while 59% of those with abnormal MPI were revascularized. CTCA indentified obstructive CAD in 113 (30%) patients accompanied in 59 (52%) patients with abnormal MPI. Referral rate for ICA was 57% for normal MPI and 88% for those with abnormal MPI, resulting in revascularization rates of 26% and 72%, respectively. Hybrid (15)O-water PET/CTCA imaging impacts clinical decision-making with regard to referral for ICA and revascularization procedures. Particularly, in the presence of an equivocal or abnormal CTCA, MPI could guide in the decision to refer for ICA and revascularization.

Rates of downstream invasive coronary angiography and revascularization: computed tomographic coronary angiography vs. Tc-99m single photon emission computed tomography

Computed tomographic coronary angiography (CTA) appears to be a useful modality for the detection of obstructive coronary artery disease (CAD). Recent data suggest that CTA may reduce the frequency of normal invasive coronary angiograms. However, there remains concern that the implementation of CTA could increase referrals to invasive coronary angiography (ICA). To further support the clinical acceptance of CTA, it is important to compare CTA to another accepted modality such as single photon emission computed tomography (SPECT). We followed a cohort of 64-slice CTA patients and a matched cohort of Tc-99m SPECT patients to determine downstream referrals for ICA and revascularization. Consecutive CTA patients (without history of revascularization or cardiac transplantation) were prospectively enrolled and compared with a Tc-99m SPECT cohort (matched for age, gender, and Morise score). Each CTA and SPECT was evaluated for obstructive CAD and patients were followed for downstream ICA and revascularization. Of the 1221 patients in each cohort, 129 (10.6%) CTA patients and 125 (10.2%) SPECT patients were referred to ICA. Of those referred to ICA, obstructive CAD was confirmed in 105 (81.4%) CTA patients and in 88 (70.4%) SPECT patients. Differences in false positive rates were significantly lower in the CTA than the SPECT cohort (9.7 and 25.8%, respectively, P = 0.009). Rates of revascularization were similar in the CTA and SPECT cohorts (6.2 vs. 5.9%, respectively). Compared with SPECT, CTA had similar referrals for ICA and revascularization rates but lower false positive rates. Computed tomographic coronary angiography appears to be a viable non-invasive diagnostic modality and does not appear to negatively impact upon ICA resources.

Limited usefulness of non-invasive coronary angiography with 16-detector multislice computer tomography at a community hospital

Objectives. To evaluate the usefulness of coronary angiography by 16-detector multislice spiral computed tomography (MSCT) in community hospital outpatients. Design. MSCT was performed at the community hospital in 157 of 218 consecutive outpatients with suspected significant coronary disease, before referral for invasive coronary angiography. Results. 101 patients had interpretable MSCT angiograms (64 men, age 62±10 years, calcium score 373±678, heart rate 56±7 beats/min, beta-blocker used by 91%). Coronary stenoses >50% were identified by invasive angiography in 49 patients. Only 79% of all segments could be assessed by MSCT due to heavy coronary calcification (12%) and blurred images (9%) in the remaining. By interpreting non-assessable segments as negative results 79 patients were correctly classified by MSCT. Sensitivity, specificity, positive and negative predictive values at patient level was 82%, 75%, 75% and 81%. By interpreting non-assessable segments as positive findings, the corresponding values were 100%, 29%, 57% and 100%, with correct diagnoses in 63% of patients. Conclusions. Limited diagnostic accuracy, non-interpretable scans and radiation exposure restrict the usefulness of coronary MSCT in a community hospital setting.