Coronary computed tomography angiography. Curr Opin Cardiol. 2011;26:392-402. [PMID: 21743316 DOI: 10.1097/hco.0b013e32834938c6]

Sex Differences in Aortic Stenosis: From the Pathophysiology to the Intervention, Current Challenges, and Future Perspectives

Calcific aortic stenosis (AS) is a major cause of morbidity and mortality in high-income countries. AS presents sex-specific features impacting pathophysiology, outcomes, and management strategies. In women, AS often manifests with a high valvular fibrotic burden, small valvular annuli, concentric left ventricular (LV) remodeling/hypertrophy, and, frequently, supernormal LV ejection fraction coupled with diastolic dysfunction. Paradoxical low-flow low-gradient AS epitomizes these traits, posing significant challenges post-aortic valve replacement due to limited positive remodeling and significant risk of patient-prosthesis mismatch. Conversely, men present more commonly with LV dilatation and dysfunction, indicating the phenotype of classical low-flow low-gradient AS, i.e., with decreased LV ejection fraction. However, these distinctions have not been fully incorporated into guidelines for AS management. The only treatment for AS is aortic valve replacement; women are frequently referred late, leading to increased heart damage caused by AS. Therefore, it is important to reassess surgical planning and timing to minimize irreversible cardiac damage in women. The integrity and the consideration of sex differences in the management of AS is critical. Further research, including sufficient representation of women, is needed to investigate these differences and to develop individualized, sex-specific management strategies.

Stent visualization methods to guide percutaneous coronary interventions and assess long-term patency

Evaluation of acute percutaneous coronary intervention (PCI) results and long-term follow-up remains challenging with ongoing stent designs. Several imaging tools have been developed to assess native vessel atherosclerosis and stent expansion, improving overall PCI results and reducing adverse cardiac events. Quantitative coronary analysis has played a crucial role in quantifying the extent of coronary artery disease and stent results. Digital stent enhancement methods have been well validated and improved stent strut visualization. Intravascular imaging remains the gold standard in PCI guidance but adds costs and time to the procedure. With a recent shift towards non-invasive imaging assessment and coronary computed tomography angiography imaging have shown promising results. We hereby review novel stent visualization techniques used to guide PCI and assess stent patency in the modern PCI era.

Coronary artery disease imaging reporting and data system (CAD-RADS): what radiologists need to know?

The aim of this work is to review Coronary Artery Disease Imaging Reporting and Data System (CAD-RADS) that was designed to standardize reporting language and improve the communication of data among radiologists and clinicians. Stenotic lesions are graded into 5 grades ranging from 0 (no stenosis) to 5 (total occlusion), where the highest grade represents the final score. The expert consensus platform has added 4 special modifiers (non-diagnostic, stent, graft, and vulnerability) to aid patient management through linking these scores with decision algorithm and treatment plan. Adherence to standard imaging protocol; knowledge of normal, variant, and anomalous anatomy; and skillful evaluation of stenosis are important for proper utilization of this reporting system. Lastly, radiologists should be aware of the inherited benefits, limitations, and common pitfalls of this classification system.

Soluble CD40 ligand expression in stable atherosclerosis: A systematic review and meta-analysis

BACKGROUND AND AIMS

The role of inflammation in atherosclerosis development and expression in different arterial territories is unclear. Soluble CD40 ligand (sCD40L) mediates inflammation and atherogenesis. Through a systematic review and meta-analysis, we assessed whether sCD40L was dysregulated in stable atherosclerosis, irrespective of the diseased arterial territory, and whether this dysregulation differed according to the specific territory.

METHODS

Systematic literature searches were performed in MEDLINE, Cochrane Library, Web of Science, and Embase for studies reporting circulating sCD40L levels in individuals with and without stable atherosclerosis. sCD40L levels were compared using random-effects meta-analysis, weighted by the inverse variance method (study protocol: PROSPERO CRD42020181392).

RESULTS

Fifty-four studies (59 estimates) including 7705 patients and 7841 controls were analyzed. sCD40L levels were found to be increased in patients with atherosclerosis, irrespective of the territory (standardized mean difference [SMD] 0.43, 95% CI 0.29-0.57; 59 estimates; χ² heterogeneity p < 0.001; I² = 92%). SMD was greatest in carotid atherosclerosis (SMD 0.58, 95% CI 0.30-0.86; 17 estimates), followed by coronary (SMD 0.43, 95% CI 0.24-0.62; 33 estimates), lower extremity (SMD 0.26, 95% CI -0.02-0.54; 7 estimates), and renal atherosclerosis (SMD -0.07, 95% CI -2.77-2.64; 2 estimates) (χ² heterogeneity p < 0.001; I² ≥ 80% for all). Subgroup analysis revealed that sCD40L levels were increased in clinical, but not subclinical, atherosclerosis.

CONCLUSIONS

sCD40L levels were increased in stable atherosclerosis, particularly in the carotid and coronary territories. These novel data support sCD40L as a marker of systemic atherosclerosis, possibly with differential roles in specific territories.

Effect of a Novel Intracycle Motion Correction Algorithm on Dual-Energy Spectral Coronary CT Angiography: A Study with Pulsating Coronary Artery Phantom at High Heart Rates

Objective

Using a pulsating coronary artery phantom at high heart rate settings, we investigated the efficacy of a motion correction algorithm (MCA) to improve the image quality in dual-energy spectral coronary CT angiography (CCTA).

Materials and Methods

Coronary flow phantoms were scanned at heart rates of 60–100 beats/min at 10-beats/min increments, using dual-energy spectral CT mode. Virtual monochromatic images were reconstructed from 50 to 90 keV at 10-keV increments. Two blinded observers assessed image quality using a 4-point Likert Scale (1 = non-diagnostic, 4 = excellent) and the fraction of interpretable segments using MCA versus conventional algorithm (CA). Comparison of variables was performed with the Wilcoxon rank sum test and McNemar test.

Results

At heart rates of 70, 80, 90, and 100 beats/min, images with MCA were rated as higher image scores compared to those with CA on monochromatic levels of 50, 60, and 70 keV (each p < 0.05). Meanwhile, at a heart rate of 90 beats/min, image interpretability was improved by MCA at a monochromatic level of 60 keV (p < 0.05) and 70 keV (p < 0.05). At a heart rate of 100 beats/min, image interpretability was improved by MCA at monochromatic levels of 50 keV (from 69.4% to 86.1%, p < 0.05), 60 keV (from 55.6% to 83.3%, p < 0.05) and 70 keV (from 33.3% to 69.3%, p < 0.05).

Conclusion

Low-keV monochromatic images combined with MCA improves image quality and image interpretability in CCTAs at high heart rates.

Comparison of cardiac output measured by use of computed tomography and thermodilution in dogs

OBJECTIVE To compare cardiac output (CO) measured by use of CT coronary angiography and thermodilution (criterion-referenced standard) at various CO values, record adverse effects, and determine the time needed to measure CO. ANIMALS 5 healthy purpose-bred Beagles (2 males and 3 females). PROCEDURES A prospective nonrandomized crossover study was conducted. Dogs were premedicated with butorphanol tartrate (0.2 mg•kg^-1, IM). Anesthesia was induced by IV administration of etomidate (1 to 2 mg•kg^-1) and midazolam (0.25 mg•kg^-1). Orotracheal intubation was performed, and anesthesia was maintained by administration of isoflurane. The CO was determined by use of thermodilution and by use of CT at 3 CO values. Dobutamine was infused at various rates to obtain the 3 CO values. RESULTS 13 values were obtained and analyzed. The mean ± SD difference between methods was 0.09 ± 0.71 L•min^-1 (95% confidence interval [CI], 0.52 to -0.34 L•min^-1). Only 1 of 13 values was located on the 100% agreement line (ie, 0 line), 7 of 13 values were located within the 95% CI, and 5 of 13 values were outside the 95% CI. CONCLUSIONS AND CLINICAL RELEVANCE For this study, there was poor agreement between the 2 methods. The 95% CI interval was 0.52 to -0.34 L•min^-1, and 5 of 13 values were outside the 95% CI. Therefore, results for the CT method appeared to be inappropriate for use in making clinical decisions.

Clinical evaluation of new automatic coronary-specific best cardiac phase selection algorithm for single-beat coronary CT angiography

The aim of this study was to evaluate the workflow efficiency of a new automatic coronary-specific reconstruction technique (Smart Phase, GE Healthcare—SP) for selection of the best cardiac phase with least coronary motion when compared with expert manual selection (MS) of best phase in patients with high heart rate. A total of 46 patients with heart rates above 75 bpm who underwent single beat coronary computed tomography angiography (CCTA) were enrolled in this study. CCTA of all subjects were performed on a 256-detector row CT scanner (Revolution CT, GE Healthcare, Waukesha, Wisconsin, US). With the SP technique, the acquired phase range was automatically searched in 2% phase intervals during the reconstruction process to determine the optimal phase for coronary assessment, while for routine expert MS, reconstructions were performed at 5% intervals and a best phase was manually determined. The reconstruction and review times were recorded to measure the workflow efficiency for each method. Two reviewers subjectively assessed image quality for each coronary artery in the MS and SP reconstruction volumes using a 4-point grading scale. The average HR of the enrolled patients was 91.1±19.0bpm. A total of 204 vessels were assessed. The subjective image quality using SP was comparable to that of the MS, 1.45±0.85 vs 1.43±0.81 respectively (p = 0.88). The average time was 246 seconds for the manual best phase selection, and 98 seconds for the SP selection, resulting in average time saving of 148 seconds (60%) with use of the SP algorithm. The coronary specific automatic cardiac best phase selection technique (Smart Phase) improves clinical workflow in high heart rate patients and provides image quality comparable with manual cardiac best phase selection. Reconstruction of single-beat CCTA exams with SP can benefit the users with less experienced in CCTA image interpretation.

Quantification of three-dimensional computed tomography angiography for evaluating coronary luminal stenosis using digital subtraction angiography as the standard of reference

Objective

We sought to evaluate the accuracy of quantitative three-dimensional (3D) CT angiography (CTA) for the assessment of coronary luminal stenosis using digital subtraction angiography (DSA) as the standard of reference.

Method

Twenty-three patients with 54 lesions were referred for CTA followed by DSA. The CTA scans were performed with 256-slice spiral CT. 3D CTA were reconstructed from two-dimensional CTA imaging sequences in order to extract the following quantitative indices: minimal lumen diameter, percent diameter stenosis (%DS), minimal lumen area, and percent area stenosis (%AS). Correlation and limits of agreement were calculated using Pearson correlation and Bland–Altman analysis, respectively. The diagnostic performance and the diagnostic concordance of 3D CTA-derived anatomic parameters (%DS, %AS) for the detection of severe coronary arterial stenosis (as assessed by DSA) were presented as sensitivity, specificity, diagnostic accuracy, and Kappa statistics. Of which vessels with %DS >50% or with %AS >75% were identified as severe coronary arterial lesions.

Result

The correlations of the anatomic parameters between 3D CTA and DSA were significant (r = 0.51–0.74, P < 0.001). Bland–Altman analysis confirmed that the mean differences were small (from −1.11 to 27.39%), whereas the limits of agreement were relatively wide (from ±28.07 to ±138.64%). Otherwise, the diagnostic accuracy (74.1% with 58.3% sensitivity and 86.7% specificity for DS%; 74.1% with 45.8% sensitivity and 96.7% specificity for %AS) and the diagnostic concordance (k = 0.46 for DS%; 0.45 for %AS) of 3D CTA-derived anatomic parameters for the detection of severe stenosis were moderate.

Conclusion

3D advanced imaging reconstruction technique is a helpful tool to promote the use of CTA as an alternative to assess luminal stenosis in clinical practice.

ECG-gated coronary angiography enables submillisievert imaging in invasive cardiology

BACKGROUND

The median dose area products (DAP) and effective doses (ED) of patients arising from coronary angiography (CA) are considerable: According the 2013 National German Registry, they amount to 19.8 Gy × cm(2) and 4.0 mSv, respectively.

METHODS

We investigated the feasibility of prospective electrocardiogram (ECG)-gated coronary angiography (CA)-a novel technique in invasive cardiology-with respect to possible reduction in irradiation effects. Instead of universally fix-rated radiographic acquisition within 7.5-15 frames/s, one single frame/heartbeat was triggered toward the diastolic moment immediately before atrial contraction (77 % of ECG-RR interval) most likely to provide motion-free and hence optimized resolution of the coronary tree. For 200 patients (body mass index 27.8 kg/m(2), age 67.5 years, male 55 %, 68 bpm) undergoing ECG-gated CA, we measured various median (interquartile range) parameters for radiation exposure.

RESULTS

The total DAP was 0.64 (0.46-1.00), radiographic fraction was 0.30 (0.19-0.43), and fluoroscopic fraction was 0.35 (0.21-0.57) Gy × cm(2). Radiographic imaging occurred within 21.7 s (17.1-26.3), with 25 frames (20-30) over the course of 7 runs (6-8). Fluoroscopy time was 119 s (94-141). Radiographic DAP was 12.6 mGy × cm(2)/frame and 13.8 mGy × cm(2)/s. Fluoroscopic DAP was 0.8 mGy × cm(2)/pulse and 3.1 mGy × cm(2)/s. Patient reference point air kerma was 17.0 mGy (11.1-28.1) and contrast volume was 70 ml (60-85).

CONCLUSION

In conclusion, invasive ECG-gated coronary imaging is feasible in clinical routine and enables patient EDs of approx. 3 % of typical values in invasive cardiology: 0.13 mSv (0.09-0.20).

Repeat coronary computed tomographic angiography in patients with a prior scan excluding significant stenosis

BACKGROUND

ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography (AUC2010) does not incorporate prior coronary computed tomographic angiography (CCTA) results in the appropriateness of a CCTA examination. The purpose of this study was to explore the criteria for forgoing repeat CCTA among patients with clinical scenarios suggesting CCTA as appropriate after prior CCTA excluding coronary artery disease.

METHODS AND RESULTS

Among patients from a single center (February 2006 to April 2013) who underwent appropriate CCTA based on AUC2010, consecutive 555 CCTAs, which had a prior CCTA excluding significant stenosis (>50% stenosis in diameter), were selected. The median time difference between the studies was 34.2 (Q1-Q3, 22.9-50.1) months. Significant stenosis was detected at the time of repeat scan (by CCTA or subsequent catheter angiography) in 13.3% (74 of 555). A multivariable logistic model (C-statistic, 0.74; bootstrapped overfitting bias, 0.8%) identified 3 predictors of significant stenosis: time difference between the studies >3 years (adjusted odds ratio, 2.1; 95% confidence interval, 1.2-3.5), diabetes mellitus (odds ratio, 2.4; 95% confidence interval,1.4-4.3), and 26% to 50% stenosis on the initial CCTA (odds ratio, 5.6; 95% confidence interval, 3.2-9.6). When these 3 factors were all absent (corresponding to 31.9% of the population), the probability of significant stenosis was 4.5% (95% confidence interval, 2.7-7.4%), whereas 17.1% of patients had significant stenosis among those with at least 1 positive variable. When coronary arteries were completely normal at the initial scan, the prevalence of significant stenosis was only 1.8% irrespective of other factors, and no patient underwent revascularization.

CONCLUSIONS

Nondiabetic patients with a prior CCTA <3 years showing no or ≤25% stenosis had a <5% prevalence of significant stenosis. The value of repeat CCTA in this group is likely small, especially when the prior CCTA demonstrated normal coronaries, even if the clinical scenario considered a CCTA appropriate.

Coronary and cardiac computed tomography in the emergency room: current status and future directions

In the United States, chest pain is the second leading reason for patients to present to an emergency department (ED). Previously, those patients suspected to have acute coronary syndrome were monitored for 24 hours to determine the presence of serum biomarkers consistent with myocardial injury. However, more recently, imaging has been used to more efficiently triage these individuals and even discharge them directly from the ED. There are multiple cardiac imaging modalities; however, cardiac computed tomography now plays a significant role in the evaluation of patients with suspected acute coronary syndrome who present to the ED. In this review, we discuss the available state-of-the-art techniques for evaluating this cohort of patients, including clinical evaluation, serum biomarkers, and imaging options. Further, we analyze in detail evidence for the use of coronary computed tomography angiography to determine whether these patients can safely be discharged from the ED. Finally, we review some of the related future techniques that may become part of the accepted clinical management of these patients in the future.

Latest-generation catheterization systems enable invasive submillisievert coronary angiography

BACKGROUND

The radiation risk of patients undergoing invasive cardiology remains considerable and includes skin injuries and cancer. To date, submillisievert coronary angiography has not been considered feasible.

PATIENTS AND METHODS

In 2011, we compared results from 100 consecutive patients undergoing elective coronary angiography using the latest-generation flat-panel angiography system (FPS) with results from examinations by the same operator using 106 historic controls with a conventional image-intensifier system (IIS) that was new in 2002.

RESULTS

The median patient exposure parameters were measured as follows: dose-area product (DAP) associated with radiographic cine acquisitions (DAP(R)) and fluoroscopy (DAP(F)) scenes, radiographic frames and runs, and cumulative exposure times for radiography and fluoroscopy. On the FPS as compared to the traditional IIS, radiographic detector entrance dose levels were reduced from 164 to 80 nGy/frame and pulse rates were lowered from 12.5/s to 7.5/s during radiography and from 25/s to 4/s during fluoroscopy. The cardiologist's performance patterns remained comparable over the years: fluoroscopy time was constant and radiography time even slightly increased. Overall patient DAP decreased from 7.0 to 2.4 Gy × cm(2); DAP(R), from 4.2 to 1.7 Gy × cm(2); and DAP(F), from 2.8 to 0.6 Gy × cm(2). Time-adjusted DAP(R)/s decreased from 436 to 130 mGy × cm(2) and DAP(F)/s, from 21.6 to 4.4 mGy × cm(2). Cumulative patient skin dose with the FPS amounted to 67 mGy, and the median (interquartile range) of effective dose was 0.5 (0.3 … 0.7) mSv.

CONCLUSION

Consistent application of radiation-reducing techniques with the latest-generation flat-panel systems enables submillisievert coronary angiography in invasive cardiology.

Myocardial perfusion imaging in patients with a recent, normal exercise test

AIM: To investigate the added value of myocardial perfusion scintigraphy imaging (MPI) in consecutive patients with suspected coronary artery disease (CAD) and a recent, normal exercise electrocardiography (ECG).

METHODS: This study was a retrospective analysis of consecutive patients referred for MPI during a 2-year period from 2006-2007 at one clinic. All eligible patients were suspected of suffering from CAD, and had performed a satisfactory bicycle exercise test (i.e., peak heart rate > 85% of the expected, age-predicted maximum) within 6 mo of referral, their exercise ECG was had no signs of ischemia, there was no exercise-limiting angina, and no cardiac events occurred between the exercise test and referral. The patients subsequently underwent a standard 2-d, stress-rest exercise MPI. Ischemia was defined based on visual scoring supported by quantitative segmental analysis (i.e., sum of stress score > 3). The results of cardiac catheterization were analyzed, and clinical follow up was performed by review of electronic medical files.

RESULTS: A total of 56 patients fulfilled the eligibility criteria. Most patients had a low or intermediate ATPIII pre-test risk of CAD (6 patients had a high pre-test risk). The referral exercise test showed a mean Duke score of 5 (range: 2 to 11), which translated to a low post-exercise risk in 66% and intermediate risk in 34%. A total of seven patients were reported with ischemia by MPI. Three of these patients had high ATPIII pre-test risk scores. Six of these seven patients underwent cardiac catheterization, which showed significant stenosis in one patient with a high pre-test risk of CAD, and indeterminate lesions in three patients (two of whom had high pre-test risk scores). With MPI as a gate keeper for catheterization, no significant, epicardial stenosis was observed in any of the 50 patients (0%, 95% confidence interval 0.0 to 7.1) with low to intermediate pre-test risk of CAD and a negative exercise test. No cardiac events occurred in any patients within a median follow up period of > 1200 d.

CONCLUSION: The added diagnostic value of MPI in patients with low or intermediate risk of CAD and a recent, normal exercise test is marginal.