J. Leipsic

Diagnosis of Ischemia-Causing Coronary Stenoses by Noninvasive Fractional Flow Reserve Computed From Coronary Computed Tomographic Angiograms : Results From the Prospective Multicenter DISCOVER-FLOW (Diagnosis of Ischemia-Causing Stenoses Obtained Via Noninvasive Fractional Flow Reserve) Study

OBJECTIVES The aim of this study was to determine the diagnostic performance of a new method for quantifying fractional flow reserve (FFR) with computational fluid dynamics (CFD) applied to coronary computed tomography angiography (CCTA) data in patients with suspected or known coronary artery disease (CAD). BACKGROUND Measurement of FFR during invasive coronary angiography is the gold standard for identifying coronary artery lesions that cause ischemia and improves clinical decision-making for revascularization. Computation of FFR from CCTA data (FFR(CT)) provides a noninvasive method for identifying ischemia-causing stenosis; however, the diagnostic performance of this new method is unknown. METHODS Computation of FFR from CCTA data was performed on 159 vessels in 103 patients undergoing CCTA, invasive coronary angiography, and FFR. Independent core laboratories determined FFR(CT) and CAD stenosis severity by CCTA. Ischemia was defined by an FFR(CT) and FFR ≤0.80, and anatomically obstructive CAD was defined as a CCTA with stenosis ≥50%. Diagnostic performance of FFR(CT) and CCTA stenosis was assessed with invasive FFR as the reference standard. RESULTS Fifty-six percent of patients had ≥1 vessel with FFR ≤0.80. On a per-vessel basis, the accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 84.3%, 87.9%, 82.2%, 73.9%, 92.2%, respectively, for FFR(CT) and were 58.5%, 91.4%, 39.6%, 46.5%, 88.9%, respectively, for CCTA stenosis. The area under the receiver-operator characteristics curve was 0.90 for FFR(CT) and 0.75 for CCTA (p = 0.001). The FFR(CT) and FFR were well correlated (r = 0.717, p < 0.001) with a slight underestimation by FFR(CT) (0.022 ± 0.116, p = 0.016). CONCLUSIONS Noninvasive FFR derived from CCTA is a novel method with high diagnostic performance for the detection and exclusion of coronary lesions that cause ischemia.

Transcatheter Aortic Valve Implantation Durability of Clinical and Hemodynamic Outcomes Beyond 3 Years in a Large Patient Cohort

Background— Although short- and medium-term outcomes after transcatheter aortic valve implantation are encouraging, long-term data on valve function and clinical outcomes are limited. Methods and Results— Consecutive high-risk patients who had been declined as surgical candidates because of comorbidities but who underwent successful transcatheter aortic valve implantation with a balloon-expandable valve between January 2005 and December 2006 and survived past 30 days were assessed. Clinical, echocardiographic, and computed tomographic follow-up examinations were performed. Seventy patients who underwent successful procedures and survived longer than 30 days were evaluated at a minimum follow-up of 3 years. At a median follow-up of 3.7 years (interquartile range 3.4 to 4.3 years), survival was 57%. Survival at 1, 2, and 3 years was 81%, 74%, and 61%, respectively. Freedom from reoperation was 98.5% (1 patient with endocarditis). During this early procedural experience, 11 patients died within 30 days, and 8 procedures were unsuccessful. When these patients were included, overall survival was 51%. Transaortic pressure gradients increased from 10.0 mm Hg (interquartile range 8.0 to 12.0 mm Hg) immediately after the procedure to 12.1 mm Hg (interquartile range 8.6 to 16.0 mm Hg) after 3 years (P=0.03). Bioprosthetic valve area decreased from a mean of 1.7±0.4 cm2 after the procedure to 1.4±0.3 cm2 after 3 years (P<0.01). Aortic incompetence after implantation was trivial or mild in 84% of cases and remained unchanged or improved over time. There were no cases of structural valvular deterioration, stent fracture, deformation, or valve migration. Conclusions— Transcatheter aortic valve implantation demonstrates good medium- to long-term durability and preserved hemodynamic function, with no evidence of structural failure. The procedure appears to offer an adequate and lasting resolution of aortic stenosis in selected patients.

Impact of low-profile sheaths on vascular complications during transfemoral transcatheter aortic valve replacement.

AIMS We sought to assess the impact of low-profile sheaths on vascular complications during transfemoral transcatheter aortic valve replacement (TAVR). METHODS AND RESULTS This retrospective single-study population comprised a total of 375 consecutive patients with severe aortic stenosis who underwent transfemoral TAVR from January 2008 to November 2012. Of these, 204 (54.4%) underwent TAVR using 14-18 Fr sheaths (low-profile sheath [LPS] group), and 171 (45.6%) using 19-24 Fr sheaths (high-profile sheath [HPS] group). Vascular complications and bleeding were defined according to the VARC-2 definitions. Lower-profile sheaths were associated with a lower incidence of major vascular complications (0.5% vs. 10.5%, p<0.001), as well as a lower rate of life-threatening or major bleeding (3.4% vs. 8.3%, p=0.038). Finally, at multivariable analysis, sheath size ≥19 Fr (adjusted odds ratio [OR]: 3.06, 95% confidence interval [CI]: 1.20-7.83; p=0.019) and a sheath external diameter/minimal femoral artery diameter ratio ≥1.05 (adjusted OR: 5.79, 95% CI: 1.29-15.92, p=0.022) were found to be the only independent predictors of major and minor vascular complications. CONCLUSIONS The introduction of lower-profile sheaths has dramatically reduced the incidence of vascular complications after transfemoral TAVR, thus enhancing the safety of the procedure.

Vancouver Transcatheter Aortic Valve Replacement Clinical Pathway

We describe the development, implementation, and evaluation of a standardized clinical pathway to facilitate safe discharge home at the earliest time after transfemoral transcatheter aortic valve replacement. Between May 2012 and October 2014, the Heart Team developed a clinical pathway suited to the unique requirements of transfemoral transcatheter aortic valve replacement in contemporary practice. The components included risk-stratified minimalist periprocedure approach, standardized postprocedure care with early mobilization and reconditioning, and criteria-driven discharge home. Our aim was to reduce variation in care, identify a subgroup of patients suitable for early discharge (⩽48 hours), and decrease length of stay for all patients. We addressed barriers related to historical practices, complex multidisciplinary stakeholder engagement, and adoption of length of stay as a quality indicator. We retrospectively reviewed the experiences of 393 consecutive patients; 150 (38.2%) were discharged early. At baseline, early discharge patients had experienced less previous balloon aortic valvuloplasty, had higher left ventricular ejection fraction, better cognitive function, and were less frail than the standard discharge group (>48 hours). Early discharge was associated with the use of local anesthesia, implantation of balloon expandable device, avoidance of urinary catheter, and early removal of temporary pacemaker. Median length of stay was 1 day for early discharge and 3 days for other patients; 97.7% were discharged home. There were no differences in 30-day mortality (1.3%), disabling stroke (0.8%), or readmission (10.7%). The implementation of a transcatheter aortic valve replacement clinical pathway shifted the program’s approach to combine standardized processes and individual risk stratification. The Vancouver transcatheter aortic valve replacement clinical pathway requires a rigorous assessment to determine its efficacy, safety, and reproducibility.

Ultra-short echo-time pulmonary MRI: evaluation and reproducibility in COPD subjects with and without bronchiectasis.

To evaluate ultra‐short‐echo‐time (UTE) MRI pulmonary signal‐intensity measurements and reproducibility in chronic obstructive pulmonary disease (COPD).

Transcatheter Mitral Valve Replacement for the Treatment of Mitral Regurgitation : In-Hospital Outcomes of an Apically Tethered Device

Mitral regurgitation (MR) is a leading cause of valvular heart disease. Although conventional mitral valve surgery is the gold standard, as many as 49% of patients with severe MR may not undergo conventional surgery [(1)][1]. Following on from the successful roll out of transcatheter aortic valve

Real-World Estimated Effective Radiation Doses From Commonly Used Cardiac Testing and Procedural Modalities

BACKGROUND The volume of cardiac diagnostic tests that are performed has increased significantly in recent years. The benefits of these tests should be weighed against the risks, including exposure to ionizing radiation. We sought to determine the effective radiation doses associated with common cardiac imaging studies performed at a provincial referral heart centre in Vancouver, Canada, between January 1, 2009 and December 31, 2009. METHODS Effective radiation dose was calculated for all patients who underwent clinically indicated cardiac computed tomography angiography (CCTA), myocardial perfusion imaging (MPI), and diagnostic catheter coronary angiography (CCA) in 2009. The dose from CCTA and CCA studies was estimated from dose-length product and dose area product values, respectively. A conversion factor of 0.014 mSv/(mGy × cm) was used for CCTA and MPI CT attenuation correction. The conversion factor for CCA was 0.22 mSv/(Gy × cm(2)). The effective radiation dose for MPI was calculated using: E = (E/A) × A(o) where E = effective dose, E/A is an effective dose coefficient, and A(o) is the radiotracer activity. RESULTS There were 673 CCTA studies and 2306 MPI studies performed with average effective doses of 3.7 mSv and 16.8 mSv, respectively. There were 2628 diagnostic CCA studies performed with an average effective dose of 11.4 mSv. CONCLUSIONS There was a wide range of effective radiation doses between imaging modalities. These tests provide different clinical information and the appropriate test must be chosen with radiation dose in mind. The implementation of dose reduction strategies has the potential to significantly reduce these doses.

Fractional flow reserve derived from coronary CT angiography in stable coronary disease: a new standard in non-invasive testing?

AbstractFractional flow reserve (FFR) measured during invasive coronary angiography is the gold standard for lesion-specific decisions on coronary revascularization in patients with stable coronary artery disease (CAD). Current guidelines recommend non-invasive functional or anatomic testing as a gatekeeper to the catheterization laboratory. However, the “holy grail” in non-invasive testing of CAD is to establish a single test that quantifies both coronary lesion severity and the associated ischemia. Most evidence to date of such a test is based on the addition of computational analysis of FFR to the anatomic information obtained from standard-acquired coronary CTA data sets at rest (FFRCT). This review summarizes the clinical evidence for the use of FFRCT in stable CAD in context to the diagnostic performance of other non-invasive testing modalities. Key Points • The process of selecting appropriate patients for invasive coronary angiography is inadequate • Invasive fractional flow reserve is the standard for assessing coronary lesion-specific ischemia • Fractional flow reserve may be derived from standard coronary CT angiography (FFRCT) • FFRCTprovides high diagnostic performance in stable coronary artery disease

Canadian Heart Rhythm Society and Canadian Association of Radiologists consensus statement on magnetic resonance imaging with cardiac implantable electronic devices.

Magnetic resonance imaging (MRI) has historically been considered contraindicated for individuals with cardiac implantable electronic devices (CIEDs) such as pacemakers and implantable defibrillators. Magnetic resonance scanners produce magnetic fields that can interact negatively with the metallic components of CIEDs. However, as CIED technology has advanced, newer MRI conditional devices have been developed that are now in clinical use and these systems have had demonstrated safety in the MRI environment. Despite the supportive data of such CIED systems, physicians remain reluctant to perform MRI scanning of conditional devices. This joint statement by the Canadian Heart Rhythm Society and the Canadian Association of Radiologists describes a collaborative process by which CIED specialists and clinics can work with radiology departments and specialists to safely perform MRI in patients with MRI conditional CIED systems. The steps required for patient and scanning preparation and the roles and responsibilities of the CIED and radiology departments are outlined. We also briefly outline the risks and a process by which patients with nonconditional CIEDs might also receive MRI in highly specialized centres. This document supports MRI in patients with MRI conditional CIEDs and offers recommendations on how this can be implemented safely and effectively.

Canadian Association of Radiologists: Consensus Guidelines and Standards for Cardiac CT.

Invasive coronary angiography remains the gold standard for imaging of the coronary arteries. Because of poor temporal and spatial resolution, noninvasive imaging of the heart using computed tomography (CT) had remained a challenge until the recent past. Since 1999, and the advent of 4-detector electrocardiogram (ECG)-gated CT, there have been rapid technical developments in CT technology and postprocessing tools, thus enabling an accurate noninvasive assessment of cardiac anatomy including the coronary arteries as well as cardiac function. Today, this relatively new technique increasingly is being requested and performed on a routine basis. Although guidelines and standards for the performance of cardiac CT (CCT) have been published by other societies outside of Canada [1e5], the Canadian Association of Radiologists recognizes that Canadian radiologists play a leading and pivotal role in the safe and proper implementation of CCT throughout the country, as well as in the training and continuing medical education of physicians performing and interpreting CCT studies. This comprehensive article reviews the current evidence for CCT to date and outlines the standards for the implementation of a CCT program. Based on the review of the current literature and on