Complementary pre-operative risk assessment using coronary computed tomography angiography and nuclear myocardial perfusion imaging in non-cardiac surgery: A VISION-CTA sub-study.

BACKGROUND: The incremental value and optimal utilization of non-invasive testing for prediction of peri-operative cardiac events during non-cardiac surgery are not clear. METHODS: A sub-study of VISION-CTA was performed using patients who underwent both coronary computed tomography angiography (CCTA) and nuclear myocardial perfusion imaging (MPI) as part of their pre-operative assessment. CCTA images were compared with MPI to determine the correlation between ischemia and obstructive coronary artery disease (CAD). Patients were followed post-operatively for 30 days and primary outcomes were all-cause death and non-fatal myocardial infarction. The predictive capacity of CCTA and nuclear MPI in predicting peri-operative major adverse cardiac event (MACE) was analyzed. RESULTS: A total of 55 patients (mean age 68.5 ± 8.4 years, 80.0% male) were analyzed. There was a strong correlation between the degree of obstructive CAD and the severity of perfusion abnormalities. Patients with severe CAD (≥ 70% stenosis) had a higher summed stress score than those without severe CAD [4.88 ± 1.22 and 1.30 ± 0.62, respectively (P < .05)]. Similarly summed difference score was significantly higher in patients with severe CAD [1.33 ± 0.46 and 0.17 ± 0.17 (P < .05)]. At 30 days there was a total of 8 (14.5%) MACE. The rate of MACE was higher in patients with severe CAD than those without (20.7% and 7.7%, respectively). Myocardial ischemia appeared to be predictive of MACE with an unadjusted odds ratio of 14.63 (P = .003). The predictive capacity of MPI further improved when only those patients with severe CAD were included (33.00) with a sensitivity, specificity, positive predictive value, and negative predictive value of 100% (79.4-100.0), 72.7% (49.8-89.3), 50.0% (21.1-78.9), and 100% (79.4-100.0), respectively. CONCLUSION: Although patients with significant obstructive disease are at risk of peri-operative MACE, the absolute event rate is low. Our data, albeit hypothesis generating, suggest that the peri-operative risk may be refined further by employing nuclear MPI in those with obstructive disease on CCTA.

Comparison of visual assessment and computer image analysis of intracoronary thrombus type by optical coherence tomography.

BACKGROUND: Analysis of intracoronary thrombus type by optical coherence tomography (OCT) imaging is highly subjective. We aimed to compare a newly developed image analysis method to subjective visual classification of thrombus type identified by OCT. METHODS: Thirty patients with acute ST elevation myocardial infarction were included. Thrombus type visually classified by two independent readers was compared with analysis using QCU-CMS software. RESULTS: Repeatability of the computer-based measurements was good. By using a ROC, area under curve values for discrimination of white and red thrombi were 0.92 (95% confidence intervals (CI) 0.83-1.00) for median attenuation, 0.96 (95% CI 0.89-1.00) for mean backscatter and 0.96 (95% CI 0.89-1.00) for mean grayscale intensity. Median attenuation of 0.57 mm-1 (sensitivity 100%, specificity 71%), mean backscatter of 5.35 (sensitivity 92%, specificity 94%) and mean grayscale intensity of 120.1 (sensitivity 85%, specificity 100%) were identified as the best cut-off values to differentiate between red and white thrombi. CONCLUSIONS: Attenuation, backscatter and grayscale intensity of thrombi in OCT images differentiated red and white thrombi with high sensitivity and specificity. Measurement of these continuous parameters can be used as a less user-dependent method to characterize in vivo thrombi. The clinical significance of these findings needs to be tested in further studies.

Culprit lesion thrombus burden after manual thrombectomy or percutaneous coronary intervention-alone in ST-segment elevation myocardial infarction: the optical coherence tomography sub-study of the TOTAL (ThrOmbecTomy versus PCI ALone) trial.

AIMS: Manual thrombectomy has been proposed as a strategy to reduce thrombus burden during primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI). However, the effectiveness of manual thrombectomy in reducing thrombus burden is uncertain. In this substudy of the TOTAL (ThrOmbecTomy versus PCI ALone) trial, we compared the thrombus burden at the culprit lesion using optical coherence tomography (OCT) in patients treated with thrombectomy vs. PCI-alone. METHODS AND RESULTS: The TOTAL trial (N = 10 732) was an international, multicentre, randomized trial of thrombectomy (using the Export catheter, Medtronic Cardiovascular, Santa Rosa, CA, USA) in STEMI patients treated with primary PCI. The OCT substudy prospectively enrolled 214 patients from 13 sites in 5 countries. Optical coherence tomography was performed immediately after thrombectomy or PCI-alone and then repeated after stent deployment. Thrombus quantification was performed by an independent core laboratory blinded to treatment assignment. The primary outcome of pre-stent thrombus burden as a percentage of segment analysed was 2.36% (95% CI: 1.73-3.22) in the thrombectomy group and 2.88% (95% CI: 2.12-3.90) in the PCI-alone group (P = 0.373). Absolute pre-stent thrombus volume was not different (2.99 vs. 3.74 mm(3), P = 0.329). Other secondary outcomes of pre-stent quadrants of thrombus, post-stent atherothrombotic burden, and post-stent atherothrombotic volume were not different between groups. CONCLUSION: Manual thrombectomy did not reduce pre-stent thrombus burden at the culprit lesion compared with PCI-alone. Both strategies were associated with low thrombus burden at the lesion site after the initial intervention to restore flow.

Assessment of the presence and extent of coronary collateralization by coronary computed tomographic angiography in patients with total occlusions.

Coronary computed tomography angiography (CTA) may be helpful to manage patients with chronic coronary occlusions. The aim of this study was to determine the sensitivity and specificity of CTA to detect the presence and extent of coronary collaterals as compared to invasive coronary angiography (ICA). We retrospectively evaluated 26 patients who underwent both coronary CTA and ICA within 3 weeks and demonstrated a total coronary occlusion (TIMI grade 0) in one of the major coronary arteries. CTA was performed using a 64-slice multidetector CT. The presence, and extent of collateralization was assessed by two blinded observers using the Rentrop classification for ICA. CTA accurately identified the presence and location of all 26 total occlusions. The presence of any collaterals was accurately detected in 21/23 patients [sensitivity 91% (CI: 71-98%)] and the absence in three patients [specificity 100% (CI: 29%-100%)]. The sensitivity of coronary CTA to identify patients with collateralization increased from 91 to 94% (CI: 71-99%) and 100% (CI: 59-100%) for collaterals Rentrop grade 2 and 3 in ICA, respectively. Coronary CTA accurately detects the presence of any coronary collateralization in patients with total occlusions. Although CT technology is currently limited in the assessment of individual collaterals and smaller vessels, it may be helpful in the management of patients with total occlusions.

Computed tomographic coronary angiographic assessment of high-risk coronary anatomy in patients with suspected coronary artery disease and intermediate pretest probability.

BACKGROUND: It is unclear if computed tomographic coronary angiography (CTA), an evolving technique for the evaluation of coronary artery disease (CAD), can identify patients with high-risk coronary anatomy. METHODS: Among patients referred for invasive angiography at Hamilton Health Sciences (Hamilton, Ontario, Canada), those with an intermediate pretest probability (25%-60% likelihood of a significant stenosis) were prospectively identified using a multivariate risk score and were studied on a 64-detector Toshiba Aquilion scanner (Toshiba Medical Systems, Tokyo, Japan) before invasive angiography. Patients with high-risk anatomy (left main, 3-vessel CAD, or 2-vessel CAD involving the proximal left anterior descending artery) or at least 1 significant stenosis were identified on CTA and invasive angiography, and the results of these modalities were compared on a per patient basis. RESULTS: Eighty patients were enrolled in the study (mean age 56 +/- 9 years, male-female ratio 43:37). Nondiagnostic scan results were obtained in 5 patients (6%). By CTA, 13 patients had high-risk anatomy and 31 patients had at least 1 significant stenosis. For the per patient detection of high-risk anatomy, CTA had 100% sensitivity (95% CI 69%-100%), 95% specificity (95% CI 86%-95%), a positive likelihood ratio of 18.0 (95% CI 6.4-50.3), and a negative likelihood ratio of 0.05 (95% CI 0-0.072). Revascularization was performed in 100% of patients with high-risk anatomy on CTA, 83% with at least 1 significant stenosis on CTA, and 0% without a significant stenosis on CTA. CONCLUSION: In appropriately selected patients, CTA is a highly sensitive and specific technique for the detection of high-risk anatomy and maybe a valuable method for noninvasive risk stratification.