Carole Dennie

Prognostic Value of 64-Slice Cardiac Computed Tomography: Severity of Coronary Artery Disease, Coronary Atherosclerosis, and Left Ventricular Ejection Fraction

OBJECTIVES We sought to determine the prognostic and incremental value of coronary artery disease (CAD) severity, coronary atherosclerosis, and left ventricular ejection fraction (LVEF) measured with cardiac computed tomography angiography (CTA). BACKGROUND CTA is an emerging tool used for the detection of obstructive CAD. However, there are limited data supporting the prognostic value of 64-slice CTA and its ability to predict all-cause mortality and major adverse cardiac events such as cardiac death and nonfatal myocardial infarction. METHODS Consecutive patients (without history of revascularization, heart transplantation, and congenital heart disease) were prospectively enrolled. Each CTA was evaluated for CAD severity, total plaque score, and LVEF. Patients were followed, and all events were confirmed with death certificates or hospital or physician records and reviewed by a clinical events committee. RESULTS Between February 2006 and February 2008, 2,076 consecutive patients were prospectively enrolled and followed for a mean of 16 +/- 8 months. At follow-up, a total of 31 (1.5%) patients had cardiac death or nonfatal myocardial infarction and 47 (2.3%) had all-cause mortality or nonfatal myocardial infarction. Multivariate analysis showed that CAD severity (hazard ratio [HR]: 3.02; 95% confidence interval [CI]: 1.89 to 4.83) was a predictor of major adverse cardiac events and that LVEF (HR: 1.47; 95% CI: 1.17 to 1.86) had incremental value over CAD severity. Total plaque score had incremental value over CAD severity and LVEF for all-cause mortality and nonfatal myocardial infarction (HR: 1.17; 95% CI: 1.06 to 1.29). CONCLUSIONS Using CTA, CAD severity, LVEF, and total plaque score seems to have prognostic and incremental value over routine clinical predictors. Cardiac CTA seems to be a promising noninvasive modality with prognostic value.

Diagnostic accuracy and impact of computed tomographic coronary angiography on utilization of invasive coronary angiography.

Background—Computed tomographic coronary angiography (CTA), given its high negative predictive value, is a potential gatekeeper for invasive coronary angiography (ICA). Before CTA can be further accepted into clinical practice, its impact on healthcare resources needs to be better understood. We sought to determine the clinical impact of CTA on ICA referrals, CTA accuracy, and normalcy rate. Methods and Results—To determine the impact of CTA, consecutive patients (n=7017) undergoing ICA before and after implementing a dedicated cardiac CT program were reviewed and compared with 3 other centers (n=11 508). To determine CTA accuracy, we evaluated consecutive CTA patients who underwent ICA. For normalcy rate, we identified patients with a low pretest probability for obstructive coronary artery disease. With the implementation of a cardiac CT program, the frequency of normal ICA decreased from 31.5% (1114 of 3538 patients) to 26.8% (932 of 3479 patients) (P<0.001). These findings were significantly different (P=0.003) from the 3 centers, in which normal ICAs were unchanged (30.0% [1870 of 6224 patients] to 31.0% [1642 of 5284 patients]). CTA had excellent per-patient sensitivity (99% [CI, 95% to 100%]), positive predictive value (92% [CI, 86% to 96%]) and negative predictive value (95% [CI, 72% to 100%]). Because of referral bias, specificity (64% [CI, 44% to 81%]) was low; however, the normalcy rate of CTA was 94% (CI, 90% to 97%). After adjusting for referral bias, the adjusted sensitivity was 90% (CI, 89% to 91%), and the adjusted specificity was 95% (CI, 94% to 96%), with positive and negative predictive values of 92% (CI, 91% to 93%) and 93% (CI, 92% to 94%), respectively. Conclusion—The clinical implementation of CTA appears to positively impact ICA by reducing the frequency of normal ICA. The operating characteristics of CTA support its potential role as a tool useful in ruling out obstructive coronary artery disease.

ALCAPA Syndrome: Not Just a Pediatric Disease

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) syndrome is a rare congenital coronary artery anomaly. There are two types of ALCAPA syndrome: the infant type and the adult type, each of which has different manifestations and outcomes. Infants experience myocardial infarction and congestive heart failure, and approximately 90% die within the 1st year of life. Rarely, ALCAPA syndrome manifests in adults; it may be an important cause of sudden cardiac death. Historically, ALCAPA syndrome was diagnosed at conventional angiography. However, the development of electrogardiographically gated multidetector computed tomographic (CT) angiography and magnetic resonance (MR) imaging enables accurate noninvasive imaging. At MR imaging and multidetector CT angiography, findings include direct visualization of the left coronary artery arising from the main pulmonary artery. Reversed flow from the left coronary artery into the main pulmonary artery may be seen at steady-state free-precession cine and fast cine phase-contrast MR imaging. Because of its ability to assess myocardial viability, which can be used as a prognostic factor to direct the need for surgical repair, MR imaging plays an important role in patient treatment. Restoration of a dual-coronary-artery system is the ideal surgical treatment for ALCAPA syndrome.

Pulmonary Hypertension: How the Radiologist Can Help

Pulmonary hypertension is defined as an abnormal elevation of pressure in pulmonary circulation, with a mean pulmonary arterial pressure higher than 25 mmHg, regardless of the underlying mechanism. The clinical classification system for pulmonary hypertension was updated at the fourth World Symposium on Pulmonary Hypertension in Dana Point, California, in 2008. In patients with suspected pulmonary hypertension, the diagnostic approach includes four stages: suspicion, detection, classification, and functional evaluation. It is crucial to understand the advantages and disadvantages of the different imaging tools available for the diagnostic work-up and follow-up of patients with pulmonary hypertension. Many conditions that cause pulmonary hypertension have suggestive findings at multidetector computed tomography or magnetic resonance imaging; some causes may be surgically treatable, whereas others may demonstrate adverse reactions to vasodilator therapies used during the course of treatment. Therefore, the radiologist plays an important role in evaluating patients with this disease. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.321105232/-/DC1.

Chronic thromboembolic pulmonary arterial hypertension: correlation of postoperative results of thromboendarterectomy with preoperative helical contrast-enhanced computed tomography.

Introduction: Pulmonary thromboendarterectomy is the treatment of choice for patients with chronic thromboembolic pulmonary arterial hypertension (CTEPH). Some patients do poorly after this procedure and may be better candidates for heart–lung transplant. The purpose of this study was to correlate preoperative findings on helical contrast-enhanced computed tomography (CT) with surgical outcome. Methods: Thirty-seven patients (mean age 52.9, range 22–71) who underwent pulmonary thromboendarterectomy and had preoperative helical contrast-enhanced CT followed by High Resolution CT (HRCT) scans were included in the study. The CTs were evaluated for the presence of central and segmental disease and for the presence of mosaic perfusion pattern. Results: The presence of central disease, as well as the presence of segmental disease, correlated negatively with the postoperative mean pulmonary arterial pressure [r(c) = −0.401, P = 0.015, r(s) = −0.38, P = 0.024)] and the pulmonary vascular resistance [(r(c) = −0.37, P = 0.027, r(s) = −0.39, P = 0.019]. No correlation was found between the clinical variables and the presence of mosaic perfusion pattern. Conclusion: Patients with CTEPH and evidence of chronic PE in the central or segmental pulmonary arteries have a better clinical outcome after pulmonary thromboendarterectomy than patients without these findings. The presence of mosaic perfusion pattern is not helpful in predicting postoperative outcome.

Alternative Imaging Modalities in Ischemic Heart Failure (AIMI-HF) IMAGE HF Project I-A: study protocol for a randomized controlled trial

BackgroundIschemic heart disease (IHD) is the most common cause of heart failure (HF); however, the role of revascularization in these patients is still unclear. Consensus on proper use of cardiac imaging to help determine which candidates should be considered for revascularization has been hindered by the absence of clinical studies that objectively and prospectively compare the prognostic information of each test obtained using both standard and advanced imaging.Methods/DesignThis paper describes the design and methods to be used in the Alternative Imaging Modalities in Ischemic Heart Failure (AIMI-HF) multi-center trial. The primary objective is to compare the effect of HF imaging strategies on the composite clinical endpoint of cardiac death, myocardial infarction (MI), cardiac arrest and re-hospitalization for cardiac causes.In AIMI-HF, patients with HF of ischemic etiology (n = 1,261) will follow HF imaging strategy algorithms according to the question(s) asked by the physicians (for example, Is there ischemia and/or viability?), in agreement with local practices. Patients will be randomized to either standard (SPECT, Single photon emission computed tomography) imaging modalities for ischemia and/or viability or advanced imaging modalities: cardiac magnetic resonance imaging (CMR) or positron emission tomography (PET). In addition, eligible and consenting patients who could not be randomized, but were allocated to standard or advanced imaging based on clinical decisions, will be included in a registry.DiscussionAIMI-HF will be the largest randomized trial evaluating the role of standard and advanced imaging modalities in the management of ischemic cardiomyopathy and heart failure. This trial will complement the results of the Surgical Treatment for Ischemic Heart Failure (STICH) viability substudy and the PET and Recovery Following Revascularization (PARR-2) trial. The results will provide policy makers with data to support (or not) further investment in and wider dissemination of alternative ‘advanced’ imaging technologies.Trial registrationNCT01288560

Discordance between Framingham Risk Score and atherosclerotic plaque burden.

AIM Clinical predictors are routinely used to identify individuals who may benefit from aggressive risk factor modification. However, clinical predictors cannot account for all genetic and environmental variables. The objective of this study is to investigate the association of Framingham Risk Score (FRS) with computed tomography angiography (CTA) measures of coronary atherosclerosis. METHODS AND RESULTS Consecutive patients who underwent CTA were prospectively enrolled and categorized according to clinical predictors such as FRS and pre-test probability for obstructive coronary artery disease (CAD). Atherosclerotic calcific and non-calcific plaques were assessed. Of the 1507 patients without a history of diabetes mellitus, myocardial infarction, and not on statin therapy, coronary atherosclerosis was present in 63.5% of the patients. Of the 1173 patients with low and intermediate FRS, atherosclerotic plaque was visually present in 47.6 and 72.7% of the patients, respectively. A higher proportion of low FRS patients had isolated non-calcific plaque (14.8%) compared with patients in the intermediate (10.1%) or high (7.2%) FRS groups, and 11.7% of high FRS patients had no visual evidence of plaque. The correlation between FRS and plaque was fair (r = 0.48; P < 0.001). CONCLUSION Although clinical variables are predictive of CAD events, CTA identified coronary atherosclerosis in a significant proportion of patients with low to intermediate FRS, and a small minority of patients with high FRS had no evidence of atherosclerosis. Prospective studies are required to determine the potential value of identifying coronary atherosclerosis using CTA and to assess whether modifying therapies based on these results are warranted.

Results of the Minimally Invasive Coronary Artery Bypass Grafting Angiographic Patency Study.

OBJECTIVE Minimally invasive coronary artery bypass grafting is safe and widely applicable, and may be associated with fewer transfusions and infections, and better recovery than standard coronary artery bypass grafting. However, graft patency rates remain unknown. The Minimally Invasive Coronary Artery Bypass Grafting Patency Study prospectively evaluated angiographic graft patency 6 months after minimally invasive coronary artery bypass grafting. METHODS In this dual-center study, 91 patients were prospectively enrolled to undergo minimally invasive coronary artery bypass grafting via a 4- to 7-cm left thoracotomy approach. The left internal thoracic artery, the ascending aorta for proximal anastomoses, and all coronary targets were directly accessed without endoscopic or robotic assistance. The study primary outcome was graft patency at 6 months, using 64-slice computed tomography angiography. Secondary outcomes included conversions to sternotomy and major adverse cardiovascular events (Clinical Trial Registration Unique identifier: NCT01334866). RESULTS The mean age of patients was 64 ± 8 years, the mean ejection fraction was 51% ± 11%, and there were 10 female patients (11%) in the study. Surgeries were performed entirely off-pump in 68 patients (76%). Complete revascularization was achieved in all patients, and the median number of grafts was 3. There was no perioperative mortality, no conversion to sternotomy, and 2 reopenings for bleeding. Transfusion occurred in 24 patients (26%). The median length of hospital stay was 4 days, and all patients were followed to 6 months, with no mortality or major adverse cardiovascular events. Six-month computed tomography angiographic graft patency was 92% for all grafts and 100% for left internal thoracic artery grafts. CONCLUSIONS Minimally invasive coronary artery bypass grafting is safe, feasible, and associated with excellent outcomes and graft patency at 6 months post-surgery.

Functional and Exercise Limitations After a First Episode of Pulmonary Embolism: Results of the ELOPE Prospective Cohort Study

Background We aimed to determine the frequency and predictors of exercise limitation after pulmonary embolism (PE) and to assess its association with health‐related quality of life (HRQoL) and dyspnea. Methods One hundred patients with acute PE were recruited at five Canadian hospitals from 2010 to 2013. Cardiopulmonary exercise testing (CPET) was performed at 1 and 12 months. Quality of life (QoL), dyspnea, 6‐min walk distance (6MWD), residual clot burden (perfusion scan, CT pulmonary angiography), cardiac function (echocardiography), and pulmonary function tests (PFTs) were measured during follow‐up. The prespecified primary outcome was percent predicted peak oxygen uptake (Vo2 peak) < 80% at 1‐year CPET. Results At 1 year, 40 of 86 patients (46.5%) had percent predicted Vo2 peak < 80% on CPET, which was associated with significantly worse generic health‐related QoL (HRQoL), PE‐specific HRQoL and dyspnea scores, and significantly reduced 6MWD at 1 year. Predictors of the primary outcome included male sex (relative risk [RR], 3.2; 95% CI, 1.3‐8.1), age (RR, 0.98; 95% CI, 0.96‐0.99 per 1‐year age increase), BMI (RR 1.1; 95% CI, 1.01‐1.2 per 1 kg/m2 BMI increase), and smoking history (RR, 1.8; 95% CI, 1.1‐2.9), as well as percent predicted Vo2 peak < 80% on CPET at 1 month (RR, 3.8; 95% CI,1.9‐7.2), and 6MWD at 1 month (RR, 0.82; 95% CI, 0.7‐0.9 per 30‐m increased walking distance). Baseline or residual clot burden was not associated with the primary outcome. Mean PFT and echocardiographic results (pulmonary artery pressure, right and left ventricular systolic function) at 1 year were similarly within normal limits in both patients with exercise limitations and those without such limitations. Conclusions Almost half of patients with PE have exercise limitation at 1 year that adversely influences HRQoL, dyspnea, and walking distance. CPET or 6MWD testing at 1 month may help to identify patients with a higher risk of exercise limitation at 1 year after PE. Based on our results, we believe that the deconditioning that occurs after acute PE could underlie this exercise limitation, but we cannot exclude the fact that this may have been present before PE. Trial Registry ClinicalTrials.gov; No.: NCT01174628; URL: www.clinicaltrials.gov.

Ultrathin needle (25 G) aspiration lung biopsy: diagnostic accuracy and complication rates.

The aim of this study was to evaluate the diagnostic accuracy and complication rate of 25-G fine-needle aspiration biopsy (FNAB) of the lung in patients with suspected malignant focal lesions and abnormal lung function. The 25-G FNAB was performed in 123 patients who underwent prebiopsy CT and pulmonary function tests. Retrospective evaluation included pulmonary function, cytology, size of the lesion, depth of location, presence of emphysema on CT, needle passes, pneumothorax and drainage. The final diagnosis (gold standard) was based on histopathology after surgical resection or follow-up and response to treatment. Sixty-one patients had normal lung function or mild impairment (group 1) and 62 had moderate or severe impairment (group 2). Pneumothorax occurred in 26 of 126 procedures (20.6%) with drainage needed in 11 (8.7%). In group 2 pneumothorax occurred in 19 of 63 procedures (30.15%) with drainage needed in 11 (17.5%). The sensitivity, specificity and diagnostic accuracy of cytology results were 93.6, 100 and 94.4%, respectively. FEV1 (p=0.014), FEV1/FVC (p=0.005), FEF25—75 (p=0.001), DLCO (p=0.013) and presence of emphysema on CT (p<0.001) correlated with pneumothorax (Student’s t test). The 25-G lung FNAB is accurate and safe in diagnosing malignancy in patients with severe lung functional abnormality. Patients with moderate to severe airway obstruction have a higher prevalence of pneumothorax than patients with mild or no functional impairment.