Arthur Nasis

Computed tomography stress myocardial perfusion imaging in patients considered for revascularization: a comparison with fractional flow reserve

AIMS Adenosine stress computed tomography myocardial perfusion imaging (CTP) is an emerging non-invasive method for detecting myocardial ischaemia. Its value when compared with fractional flow reserve (FFR), a highly accurate index of ischaemia, is unknown. Our aim was to determine the diagnostic accuracy of CTP and its incremental value when used with computed tomography coronary angiography (CTA) for detecting ischaemia compared with FFR. METHODS AND RESULTS Forty-two patients (126 vessel territories), who had at least one ≥50% angiographic stenosis on invasive angiography considered for non-urgent revascularization, were included and underwent FFR and CT assessment, including CTP, delayed contrast enhancement scan and CTA all acquired using 320-detector row CT, and prospective ECG gating. Fractional flow reserve was determined in 86 territories subtended by vessels with ≥50% stenosis upon visual assessment. Fractional flow reserve ≤0.8 was considered to indicate significant ischaemia. Computed tomography myocardial perfusion imaging correctly identified 31/41 (76%) ischaemic territories and 38/45 (84%) non-ischaemic territories. Per-vessel territory sensitivity, specificity, positive, and negative predictive values of CTP were 76, 84, 82, and 79%, respectively. The combination of a ≥50% stenosis on CTA and perfusion defect on CTP was 98% specific for ischaemia, while the presence of <50% stenosis on CTA and normal perfusion on CTP was 100% specific for exclusion of ischaemia. Mean radiation for CTP and combined CT was 5.3 and 11.3 mSv, respectively. CONCLUSION Computed tomography myocardial perfusion imaging is moderately accurate in identifying perfusion defects associated with ischaemia as assessed by FFR in patients considered for revascularization. In territories, where CTA and CTP are concordant, CTA/CTP is highly accurate in the detection and exclusion of ischaemia. This is achievable with acceptable radiation exposure using 320-detector row CT and prospective ECG gating.

Current and Evolving Clinical Applications of Multidetector Cardiac CT in Assessment of Structural Heart Disease

Multidetector computed tomography (CT) has an established role in the evaluation of selected patients suspected of having coronary disease; however, in addition to coronary assessment, multidetector CT can be used to evaluate numerous noncoronary structures in the same examination. In particular, the use of multidetector CT to provide pulmonary and cardiac venous anatomic information prior to electrophysiology procedures is well established, and its important role in the periprocedural evaluation of patients undergoing percutaneous procedures, such as transcatheter aortic valve replacement and left atrial appendage device occlusion, is being increasingly recognized. Such advances have resulted in multidetector CT being increasingly used as a complementary imaging technique to echocardiography and magnetic resonance imaging for the comprehensive evaluation of cardiac structure and function in particular clinical situations. This review provides an overview of the noncoronary cardiac structures that can be evaluated with multidetector CT, and outlines the established appropriate clinical uses of multidetector CT in the assessment of structural heart disease, as well as evolving periprocedural clinical applications.

Acute Chest Pain Investigation: Utility of Cardiac CT Angiography in Guiding Troponin Measurement

PURPOSE To assess the impact on length of stay and rate of major adverse cardiovascular events of a cardiac computed tomographic (CT) angiography-guided algorithm to examine patients who present to the emergency department (ED) with low- to intermediate-risk chest pain. MATERIALS AND METHODS The study was approved by the institutional review board, and all patients gave written informed consent. Two hundred three consecutive patients (mean age, 55 years ± 11 [standard deviation]; 123 men) with low- to intermediate-risk ischemic-type chest pain were prospectively enrolled. Patients underwent initial cardiac CT angiography with subsequent treatment determined by reference to findings at cardiac CT angiography; patients without overt plaque were immediately discharged from the hospital, patients with nonobstructive plaque and mild-to-moderate stenoses were discharged after a negative 6-hour troponin level, and patients with severe stenoses were admitted to the hospital. Discharged patients were followed up for a mean of 14.2 months. Additionally, length of stay and safety outcomes among these patients were compared with those in 102 consecutive patients with low- to intermediate-risk chest pain who presented to the ED and underwent a standard of care (SOC) work-up without cardiac CT angiography. One-way analysis of variance with Bonferroni correction was used to compare length of stay between groups. RESULTS Cardiac CT angiography findings in the 203 patients who underwent cardiac CT angiography were as follows: Sixty-five (32%) patients had no plaque, 107 (53%) had nonobstructive plaque, and 31 (15%) had severe stenoses. At follow-up, there were no deaths or cases of acute coronary syndrome (cardiac CT angiography, 0%, 95% confidence interval [CI]: 0%, 1.85%; SOC, 0%, 95% CI: 0%, 3.63%), and the rate of readmission to the hospital because of chest pain was higher with the SOC approach (9% vs 1%, P = .01). Mean ED length of stay was lower with cardiac CT angiography (6.62 hours ± 0.38 after a single troponin level and 9.15 hours ± 0.30 after serial troponin levels) than with the SOC approach (11.62 hours ± 0.47, P < .001). CONCLUSION Tailoring troponin measurement to cardiac CT angiography findings is safe and allows early discharge of patients with low- to intermediate-risk chest pain, resulting in reduced length of stay.

Long-term Outcome after CT Angiography in Patients with Possible Acute Coronary Syndrome

PURPOSE To assess the long-term outcome and hospital readmission rate associated with a computed tomographic (CT) angiography-guided strategy used to examine patients who present to the emergency department (ED) with symptoms of possible acute coronary syndrome (ACS). MATERIALS AND METHODS The study was approved by the institutional review board, and all patients provided written informed consent. A total of 585 consecutive patients (mean age, 58 years ± 11 [standard deviation]; 58% were male) with ischemic-type chest pain and low to intermediate risk for ACS were evaluated prospectively. Patients underwent coronary CT angiography after single or serial troponin I (TnI) measurement, depending on time of presentation to the ED. Subsequent care was determined with CT angiography findings: Patients without plaque and patients with nonobstructive plaque and at most mild to moderate stenosis (<40% luminal narrowing) were discharged without further investigation. Patients with moderate stenosis (40%-70% narrowing) were discharged and referred for outpatient stress echocardiography. Patients with severe stenosis (>70% narrowing) were admitted. Discharged patients were contacted and their medical records were reviewed to determine rates of death, ACS, revascularization, and hospital admission. By using binomial distribution, Clopper-Pearson confidence intervals (CIs) were calculated for outcome data. RESULTS Coronary CT angiography findings were as follows: A total of 196 patients (34%) had no coronary plaque or stenosis, 288 (49%) had nonobstructive plaque, 22 (4%) had moderate stenosis, and 79 (13%) had severe stenosis. At median 47.4-month follow-up (range, 24-57 months) of the 506 discharged patients, five (1%; 95% CI: 0.4%, 2.3%) had been readmitted for chest pain; there were no instances of coronary revascularization, ACS, or death (0% for all; 95% CI: 0%, 0.7%). Follow-up was 100% complete. CONCLUSION Use of a CT angiography-guided strategy to investigate patients with low to intermediate risk of ACS who present to the ED with chest pain is safe at long-term follow-up, including patients discharged after single TnI measurement.

Superior CT coronary angiography image quality at lower radiation exposure with second generation 320-detector row CT in patients with elevated heart rate: a comparison with first generation 320-detector row CT

BACKGROUND This study aims to compare the image quality of second generation versus first generation 320-computed tomography coronary angiography (CTCA) in patients with heart rate ≥65 bpm as it has not been specifically reported. METHODS Consecutive patients who underwent CTCA using second-generation-320-detector-row-CT were prospectively enrolled. A total of 50 patients with elevated (≥65 bpm) heart rate and 50 patients with controlled (<65 bpm) heart rate were included. Age and gender matched patients who were scanned with the first-generation-320-detector-row-CT were retrospectively identified. Image quality in each coronary artery segment was assessed by two blinded CT angiographers using the five-point Likert scale. RESULTS In the elevated heart rate cohorts, while there was no significant difference in heart rate during scan-acquisition (66 vs. 69 bpm, P=0.308), or body mass index (28.5 vs. 29.6, P=0.464), the second generation scanner was associated with better image quality (3.94±0.6 vs. 3.45±0.8, P=0.001), and with lower radiation (2.8 vs. 4.3 mSv, P=0.009). There was no difference in scan image quality for the controlled heart rate cohorts. CONCLUSIONS The second generation CT scanner provides better image quality at lower radiation dose in patients with elevated heart rate (≥65 bpm) compared to first generation CT scanner.

Sinus valsalva aneurysm on cardiac CT angiography: Assessment and detection

After the advent of ECG gated cardiac CT angiography (CCTA) there has been significant improvement in image quality of the ascending aorta. As a result the sinuses of valsalva are readily assessable. Sinuses of valsalva aneurysm can cause significant dysfunction of the aortic root and annulus and can be congenital or acquired. The aneurysm most commonly originates from the right coronary sinus. Complications related to sinuses of valsalva aneurysm can cause chest pain and can be life threatening. The cardiac imager should actively assess the sinuses of valsalva in every CCTA study.

Subclinical Leaflet Thrombosis in Transcatheter Aortic Valve Replacement Detected by Multidetector Computed Tomography ― A Review of Current Evidence ―

Subclinical leaflet thrombosis (SLT) following transcatheter aortic valve replacement (TAVR) has been increasingly recognized. SLT has the hallmark features of hypo-attenuated leaflet thickening (HALT) on multidetector computed tomography (MDCT), which may result in hypoattenuation affecting motion (HAM). The actual prevalence of this condition is uncertain, with limited observational registries. SLT has caught the attention of the cardiovascular community because of concerns regarding its clinical sequelae, specifically the potential increased incidence of cerebrovascular events. There are available, albeit sparse, data to suggest that when left untreated, SLT may lead to valve deterioration with potential hemodynamic compromise and potentially clinically overt prostheses thrombosis. Some clinicians have opted to treat patients with SLT with anticoagulation. Although anticoagulation may be a rational treatment option, little data exist on the safety and efficacy of this treatment. This is particularly important considering TAVR patients also have higher bleeding risk than the standard population. In this review, we aim to summarize the current evidence on SLT, explore its pathophysiological mechanism, discuss the current treatment options and future trials that may clarify the optimal antithrombotic strategies of SLT.

Safety and efficacy of valve repositioning during transcatheter aortic valve replacement with the Lotus Valve System.

OBJECTIVE To determine the safety and efficacy of valve repositioning following transcatheter aortic valve replacement (TAVR) with the Lotus Valve System (Boston Scientific, Marlborough, MA, USA). INTRODUCTION TAVR is a well-established treatment for severe aortic stenosis. The Lotus Valve System is fully repositionable and retrievable. Valve repositioning has the potential to minimize TAVR-related complications caused by valve malposition; however, the effect on adverse event rates such as stroke is unknown. METHODS Consecutive patients with severe aortic stenosis treated with the Lotus Valve System (n=125) were prospectively recruited. Patients who did not require valve repositioning (Group A) were compared to patients who required one or more valve repositions (Group B). The primary end-point was 30-day occurrence of major adverse cardiovascular and cerebrovascular events (MACCE). Secondary end-points included each component of the primary end-point, new pacemaker insertion, and procedural or 30-day major adverse events, defined according to VARC-2 definitions. RESULTS Valve repositioning was utilized in 60.8% (76/125) of patients including 17.1% (13/76) who required full valve resheathing. The most frequent indications for valve repositioning were altering the depth and angulation of initial implantation (69.7%), reducing paravalvular regurgitation (13.2%), and attempt to correct new or worsened heart block (7.9%). Baseline characteristics were similar in both groups. The primary end-point occurred in 12.2% and 6.6% of Group A and B, respectively (p=0.10). Thirty-day new pacemaker implantation was 34.1% and 18.8% in Group A and B, respectively (p=0.06). The secondary end-point measures were not significantly different between the groups. CONCLUSION Repositioning facilitated correct anatomical positioning of all devices leading to optimal prosthesis hemodynamics and a trend to lower pacemaker rate without increased risk of MACCE.

The utility of personal activity trackers (Fitbit Charge 2) on exercise capacity in patients post acute coronary syndrome [UP-STEP ACS Trial]: a randomised controlled trial protocol

BackgroundThe benefits of physical activity and cardiovascular rehabilitation on the reduction of cardiovascular risk are well documented. Despite this, significant barriers and challenges remain in optimizing patient risk factors post acute coronary syndromes (ACS) and ensuring patient compliance. Consumer wearable personal activity trackers represent a cost effective and readily available technology that may aid in this endeavour.MethodsUP-STEP ACS is a prospective single-blinded, two-arm, parallel, randomized control trial with an aim to enrol 200 patients all undertaking cardiac rehabilitation. It will assess the affect that personal activity monitors have on change in exercise capacity in patients post acute coronary syndromes primarily measured by a six-minute walk test (6MWT). Secondary end points will be the improvement in other cardiovascular risk factors, namely; blood lipid and glucose levels, weight, waist circumference, along with mood, quality of life and cardiac rehabilitation adherence. Patients will be randomized to either receive a personal activity tracker or standard post hospital care during their index event. After the 8- week intervention period, patients will return for a clinical review and repeat of baseline assessments including the 6MWT.DiscussionThe utility and impact on exercise capacity of personal activity trackers in patient’s post-acute coronary syndrome has not been assessed. This study aims to add to the scientific evidence emerging regarding the clinical utility and validity of these devices in different patient population groups. If proven to be of benefit, these devices represent a cost effective, easily accessible technology that could aid in the reduction of cardiovascular events.Trial registrationThe trial has been registered with the Australian New Zealand Clinical Trials Registry (ANZCTR). The registration number is ACTRN12617000312347 (28/02/2017).

Coronary computed tomography angiography for the assessment of chest pain: current status and future directions.

Abstract Chest pain is one of the most common presenting symptoms leading to presentation to medical clinics and Emergency Departments worldwide. Defining the nature and etiology of chest pain can pose a diagnostic dilemma for clinicians, despite the availability of several diagnostic algorithms and guidelines to assist them in evaluating these patients. Most investigations in patients with acute chest pain are initially performed to either exclude or diagnose and manage potentially life-threatening conditions such as acute coronary syndrome, pulmonary embolism and aortic dissection. In cases of stable chest pain syndromes, the focus shifts to determining the presence, extent and severity of coronary artery disease. In recent years, coronary computed tomography angiography (CCTA) is being increasingly used worldwide in the assessment of both stable and acute chest pain syndromes. This review evaluates the current evidence regarding the clinical utility of CCTA in the stable and acute chest pain settings and outlines the latest advances in CCTA techniques, including functional assessment of coronary stenoses, and their potential clinical application to improve patient care in a cost-effective manner.