Laura Jimenez-Juan

Potential clinical impact of cardiovascular magnetic resonance assessment of ejection fraction on eligibility for cardioverter defibrillator implantation

BackgroundFor the primary prevention of sudden cardiac death, guidelines provide left ventricular ejection fraction (EF) criteria for implantable cardioverter defibrillator (ICD) placement without specifying the technique by which it should be measured. We sought to investigate the potential impact of performing cardiovascular magnetic resonance (CMR) for EF on ICD eligibility.MethodsThe study population consisted of patients being considered for ICD implantation who were referred for EF assessment by CMR. Patients who underwent CMR within 30 days of echocardiography were included. Echocardiographic EF was determined by Simpson’s biplane method and CMR EF was measured by Simpson’s summation of discs method.ResultsFifty-two patients (age 62±15 years, 81% male) had a mean EF of 38 ± 14% by echocardiography and 35 ± 14% by CMR. CMR had greater reproducibility than echocardiography for both intra-observer (ICC, 0.98 vs 0.94) and inter-observer comparisons (ICC 0.99 vs 0.93). The limits of agreement comparing CMR and echocardiographic EF were – 16 to +10 percentage points. CMR resulted in 11 of 52 (21%) and 5 of 52 (10%) of patients being reclassified regarding ICD eligibility at the EF thresholds of 35 and 30% respectively. Among patients with an echocardiographic EF of between 25 and 40%, 9 of 22 (41%) were reclassified by CMR at either the 35 or 30% threshold. Echocardiography identified only 1 of the 6 patients with left ventricular thrombus noted incidentally on CMR.ConclusionsCMR resulted in 21% of patients being reclassified regarding ICD eligibility when strict EF criteria were used. In addition, CMR detected unexpected left ventricular thrombus in almost 10% of patients. Our findings suggest that the use of CMR for EF assessment may have a substantial impact on management in patients being considered for ICD implantation.

Cardiac magnetic resonance imaging findings predict major adverse events in apical hypertrophic cardiomyopathy.

Purpose: The purpose of this study was to determine the prognostic significance of cardiac magnetic resonance imaging (MRI) findings in patients with apical hypertrophic cardiomyopathy (HCM). Materials and Methods: Cardiac MRI studies of 93 consecutive patients with apical HCM were retrospectively evaluated. Quantification of late gadolinium enhancement (LGE) was determined and expressed as a percentage of total left ventricular (LV) myocardial mass (%LGE). Morphologic features including presence of apical aneurysm, right ventricular hypertrophy, and LV thrombus were also assessed. Clinical data were collected during follow-up to assess for occurrence of major adverse events, defined as: heart failure, stroke, appropriate automatic implantable cardioverter defibrillator discharge, sustained ventricular tachycardia, aborted sudden cardiac death, and/or all-cause death. Results: The mean age of the patients was 54.9±13.8 years, and 72.0% (n=67) were male. LGE, right ventricular hypertrophy, apical aneurysm, and LV thrombus were identified in 69.4%, 25.8%, 18.3%, and 4.3%, respectively. Mean %LGE was 10.8%±11.1%. Over 2.4±1.7 years of follow-up, 14 subjects (15.1%) experienced a major adverse event (event rate, 6.3%/y): heart failure (6.5%), stroke (6.5%), appropriate automatic implantable cardioverter defibrillator discharge (2.2%), sustained ventricular tachycardia (2.2%), aborted sudden cardiac death (1.1%), and all-cause death (0.0%). Presence of apical aneurysm and extent of LGE were significant predictors of major adverse events [odds ratio (OR) 4.6, P=0.015; and OR 1.4/5% LGE, P=0.030, respectively]. Patients with both apical aneurysm and >5% LGE were at highest risk for major adverse events (OR 6.7, P=0.004) and had shortest event-free survival (P=0.001). Conclusions: Within our population of apical HCM patients, the extent of LGE and the presence of an apical aneurysm identified by cardiac MRI were both significant predictors of major adverse clinical events.

Accuracy of Right and Left Ventricular Functional Assessment by Short-Axis vs Axial Cine Steady-State Free-Precession Magnetic Resonance Imaging: Intrapatient Correlation With Main Pulmonary Artery and Ascending Aorta Phase-Contrast Flow Measurements

Objective The left ventricle (LV) is routinely assessed with cardiac magnetic resonance imaging (MRI) by using short-axis orientation; it remains unclear whether the right ventricle (RV) can also be adequately assessed in this orientation or whether dedicated axial orientation is required. We used phase-contrast (PC) flow measurements in the main pulmonary artery (MPA) and the ascending aorta (Aorta) as nonvolumetric standard of reference and compared RV and LV volumes in short-axis and axial orientations. Methods A retrospective analysis identified 30 patients with cardiac MRI data sets. Patients underwent MRI (1.5 T or 3 T), with retrospectively gated cine steady-state free-precession in axial and short-axis orientations. PC flow analyses of MPA and Aorta were used as the reference measure of RV and LV output. Results There was a high linear correlation between MPA-PC flow and RV–stroke volume (SV) short axis (r = 0.9) and RV-SV axial (r = 0.9). Bland-Altman analysis revealed a mean offset of 1.4 mL for RV axial and −2.3 mL for RV–short-axis vs MPA-PC flow. There was a high linear correlation between Aorta-PC flow and LV-SV short-axis (r = 0.9) and LV-SV axial (r = 0.9). Bland-Altman analysis revealed a mean offset of 4.8 m for LV short axis and 7.0 mL for LV axial vs Aorta-PC flow. There was no significant difference (P = .6) between short-axis–LV SV and short-axis–RV SV. Conclusion No significant impact of the slice acquisition orientation for determination of RV and LV stroke volumes was found. Therefore, cardiac magnetic resonance workflow does not need to be extended by an axial data set for patients without complex cardiac disease for assessment of biventricular function and volumes.

Cardiovascular magnetic resonance imaging predictors of pregnancy outcomes in women with coarctation of the aorta

AIMS The aim of this study was to determine associations between aortic morphometry evaluated by cardiovascular magnetic resonance (CMR) and pregnancy outcomes in women with aortic coarctation (CoA). METHODS Consecutive women with CoA seen with CMR within 2 years of delivery were reviewed. Aortic dimensions were measured on CMR angiography. Adverse outcomes (cardiovascular, obstetric, and foetal/neonatal) were documented. RESULTS We identified 28 women (4 with native and 24 with repaired CoA) who had 30 pregnancies. There were 29 live births (1 stillbirth) at mean gestation 38 ± 2 weeks. Mean maternal ages at first cardiac intervention and pregnancy were 6 ± 8 and 29 ± 6 years, respectively. There were nine cardiovascular events (hypertensive complications in five; stroke in two and arrhythmia in two) occurring in seven pregnancies. Minimum aortic dimensions were smaller in women with cardiovascular events (12.1 vs. 14.3 mm, P = 0.001), specifically in those with hypertensive complications (11.6 vs. 14.4 mm, P < 0.001). From receiver operator curve analysis, optimal discrimination for the development of adverse cardiovascular events occurred at the 12 mm diameter threshold [sensitivity 78%, specificity 91%, area under the curve 0.86 (95% CI: 0.685-1)]. All hypertensive events occurred in conjunction with a minimum aortic diameter of 12 mm (7mm/m(2)) or less. No adverse outcomes occurred if minimum diameter exceeded 15 mm. CONCLUSION Smaller aortic dimensions relate to increased risk of hypertensive events in pregnant women with CoA. CMR can aid in stratification of risk for women with CoA who are considering pregnancy.

The value of stress perfusion cardiovascular magnetic resonance imaging for patients referred from the adult congenital heart disease clinic: 5-year experience at the Toronto General Hospital

BACKGROUND Vasodilator stress perfusion cardiovascular magnetic resonance imaging is a clinically useful tool for detection of clinically significant myocardial ischaemia in adults. We report our 5-year retrospective experience with perfusion cardiovascular magnetic resonance in a large, quarternary adult congenital heart disease centre. METHODS We reviewed all cases of perfusion cardiovascular magnetic resonance in patients referred from the adult congenital heart disease service. Dipyridamole stress perfusion cardiovascular magnetic resonance was undertaken on commercially available 1.5 and 3 T cardiovascular magnetic resonance scanners. Late gadolinium enhancement imaging was performed 8-10 minutes after completion of the rest perfusion sequence. Navigator whole-heart coronary magnetic resonance angiography was also performed where feasible. RESULTS of stress cardiovascular magnetic resonance were correlated with complementary imaging studies, surgery, and clinical outcomes. RESULTS Over 5 years, we performed 34 stress perfusion cardiovascular magnetic resonance examinations (11 positive). In all, 84% of patients had further investigations for ischaemia in addition to cardiovascular magnetic resonance. Within a subgroup of 19 patients who had definitive alternative assessment of their coronary arteries, stress perfusion cardiovascular magnetic resonance demonstrated a sensitivity of 82% and specificity of 100%. Of the 34 studies, two were false negatives, in which the aetiology of ischaemia was extrinsic arterial compression rather than intrinsic coronary luminal narrowing. Coronary abnormalities were identified in 71% of cases who had coronary magnetic resonance angiography. CONCLUSION Stress perfusion cardiovascular magnetic resonance is a useful and accurate tool for investigation of myocardial ischaemia in an adult congenital heart disease population with suspected non-atherosclerotic coronary abnormalities.

Optimal assessment of right ventricular function using cardiac magnetic resonance cine imaging after Mustard palliation for transposition of the great arteries.

Background The most common cause of a systemic right ventricle is atrial redirection surgery (Mustard repair) in the setting of complete TGA. Decreased RVEF is common and is a predictor of morbidity and mortality. Cardiac magnetic resonance (CMR) cine imaging is the reference standard for assessment of right heart size and function. However, the optimal method of RV planimetry using CMR in patients with Mustard palliation for complete TGA remains unclear.

Computed tomography and magnetic resonance imaging of the coronary sinus: anatomic variants and congenital anomalies.

AbstractThe coronary sinus (CS) is an important vascular structure that allows for access into the coronary veins in multiple interventional cardiology procedures, including catheter ablation of arrhythmias, pacemaker implantation and retrograde cardioplegia. The success of these procedures is facilitated by the knowledge of the CS anatomy, in particular the recognition of its variants and anomalies. This pictorial essay reviews the spectrum of CS anomalies, with particular attention to the distinction between clinically benign variants and life-threatening defects. Emphasis will be placed on the important role of cardiac CT and cardiovascular magnetic resonance in providing detailed anatomic and functional information of the CS and its relationship to surrounding cardiac structures. Teaching Points • Cardiac CT and cardiovascular magnetic resonance offer 3D high-resolution mapping of the coronary sinus in pre-surgical planning.• Congenital coronary sinus enlargement occurs in the presence or absence of a left-to-right shunt.• Lack of recognition of coronary sinus anomalies can lead to adverse outcomes in cardiac procedures.• In coronary sinus ostial atresia, coronary venous drainage to the atria occurs via Thebesian or septal veins.• Coronary sinus diverticulum is a congenital outpouching of the coronary sinus and may predispose to cardiac arrhythmias.

Coronary Calcium Scan Acquisition Before Coronary CT Angiography: Limited Benefit or Useful Addition?

OBJECTIVE This article reviews the role of coronary calcium quantification in symptomatic patients and the pros and cons of acquiring an unenhanced coronary calcium scan in every patient with suspected coronary artery disease referred for coronary CT angiography. CONCLUSION The acquisition of a coronary calcium scan in every symptomatic patient referred for coronary CT angiography requires a case-by-case approach.

β-Blockers to Control Heart Rate during Coronary CT Angiography

We are grateful for the opportunity offered by Dr Darge in his letter to acknowledge the important nonvascular applications of microbubble contrast agents for US. While our review focused on the role of these agents in providing intravascular contrast for diagnosis ( 1 ), Dr Darge describes CE voiding urosonography, one of several established nonvascular applications of microbubbles. These include hysterosalpingo– contrast sonography ( 2 ), which is reported to be as accurate as hysterosalpingography in determining fallopian tube patency ( 3 ), and sentinel node US with intradermal injections of microbubbles, which has been validated in animal models ( 4 ) and recently demonstrated successfully in patients with breast cancer ( 5 ).

Association between conversion to in-center nocturnal hemodialysis and right ventricular remodeling

Background In-center nocturnal hemodialysis (INHD) is associated with favorable left ventricular (LV) remodeling. Although right ventricular (RV) structure and function carry prognostic significance, the impact of dialysis intensification on RV is unknown. Our objectives were to evaluate changes in RV mass index (MI), end-diastolic volume index (EDVI), end-systolic volume index (ESVI) and ejection fraction (EF) after conversion to INHD and their relationship with LV remodeling. Methods Of 67 conventional hemodialysis (CHD, 4 h/session, three times/week) patients, 30 continued on CHD and 37 converted to INHD (7-8 h/session, three times/week). Cardiac magnetic resonance imaging was performed at baseline and 1 year using a standardized protocol; an experienced and blinded reader performed RV measurements. Results At 1 year there were significant reductions in RVMI {-2.1 g/m2 [95% confidence interval (CI) -3.8 to - 0.4], P = 0.017}, RVEDVI [-9.5 mL/m2 (95% CI - 16.3 to - 2.6), P = 0.008] and RVESVI [-6.2 mL/m2 (95% CI - 10.9 to - 1.6), P = 0.011] in the INHD group; no significant changes were observed in the CHD group. Between-group comparisons showed significantly greater reduction of RVESVI [-7.9 mL/m2 (95% CI - 14.9 to - 0.9), P = 0.03] in the INHD group, a nonsignificant trend toward greater reduction in RVEDVI and no significant difference in RVMI and RVEF changes. There was significant correlation between LV and RV in terms of changes in mass index (MI) (r = 0.46), EDVI (r = 0.73), ESVI (r = 0.7) and EF (r = 0.38) over 1 year (all P < 0.01). Conclusions Conversion to INHD was associated with a significant reduction of RVESVI. Temporal changes in RV mass, volume and function paralleled those of LV. Our findings support the need for larger, longer-term studies to confirm favorable RV remodeling and determine its impact on clinical outcomes.