[Show abstract][Hide abstract] ABSTRACT: Background: Subaortic right ventricular (RV) functional assessment in patients with congenitally corrected transposition of the great arteries (ccTGA) is important for both long-term outcome and as an indication for tricuspid valve replacement. Cardiac magnetic resonance (CMR) imaging is considered the reference standard for assessment of subaortic RV systolic function. However, two-dimensional echocardiography (2DE) remains the most frequently used imaging modality in clinical practice.
Objective: To compare 2DE and CMR parameters of RV function in patients with ccTGA.
Methods: We identified adults (≥18) with the diagnosis of ccTGA who underwent consecutive CMR and 2DE imaging within 6 months between 2005 and 2015. Patients with tricuspid valve replacement or pacemaker were excluded. 2DE images were reviewed and the following RV parameters re-measured by a single observer: fractional area shortening (FAC), tricuspid annular plane systolic excursion (TAPSE), tricuspid annular systolic velocity (Ts’), the rate of systolic RV pressure increase (dp/dt) and myocardial acceleration during isovolumic contraction (IVA). RVEF as measured by CMR was recorded.
Results: There were 82 matched 2DE and CMR studies in 42 ccTGA patients (50% male). Median age at 2DE was 33.1 years (IQR = 22.7- 48.2 year). Pearson correlation analysis demonstrated a weak correlation between FAC and RVEF (r2=0.143, p=0.0005). Other 2DE parameters failed to show any correlation with RVEF (Figure 1).
Conclusion: In general, 2DE parameters for the assessment of subaortic RV systolic function correlate poorly with CMR measured RVEF in patients with ccTGA. This is important information for selection and interpretation of various modalities in the long-term follow-up of this patient population.
[Show abstract][Hide abstract] ABSTRACT: Background:
In-centre nocturnal hemodialysis (INHD, 7-8 hours/session, 3 times/week) is an increasingly utilized form of dialysis intensification, though data on the cardiovascular benefits of this modality are limited.
In this prospective cohort study, we enrolled 67 prevalent conventional hemodialysis (CHD, 4 hours/session, 3 times/week) recipients at 2 medical centres in Canada, of whom 37 converted to INHD and 30 remained on CHD. The primary outcome was the change in left ventricular mass (LVM) after 1 year as assessed by cardiac magnetic resonance imaging. Secondary outcomes included changes in serum phosphate concentration, phosphate binder burden, haemoglobin, erythropoiesis stimulating agent usage, and blood pressure.
Conversion to INHD was associated with a 14.2 (95% confidence interval [CI] 1.2-27.2) g reduction in LVM as compared with continuation on CHD. This result was maintained after adjustment for baseline imbalances between the groups and in ancillary analyses. There was a trend toward a larger drop in systolic blood pressure (9.8 [95% CI, -1.4-20.9] mm Hg) among INHD recipients with a significant reduction in the number of prescribed antihypertensive agents (0.7 [95% CI, 0.3-1.1] agents). Serum phosphate declined by 0.40 (95% CI, 0.16-0.63) mmol/L among INHD recipients without any difference in calcium-based phosphate binder requirements, as compared with those who remained on CHD.
Compared with continuation of CHD, conversion to INHD was associated with significant LVM regression and reduction in serum phosphate concentration at 1 year.
No preview · Article · Sep 2015 · The Canadian journal of cardiology
[Show abstract][Hide abstract] ABSTRACT: Objective:
Patients with repaired tetralogy of Fallot (TOF) are followed serially by cardiac magnetic resonance (CMR) for surveillance of RV dilation and dysfunction. We sought to define the prevalence of progressive RV disease and the optimal time interval between CMR evaluations.
Candidates were selected from a multicentre TOF registry and were included if ≥2 CMR studies performed ≥6 months apart were available without interval cardiovascular interventions. Patients with 'disease progression' (defined as increase in RV end-diastolic volume index (RVEDVi) ≥30 mL/m(2), decrease in RVEF ≥10% or decrease in LVEF ≥10%) were compared with those with 'disease non-progression' (defined as RVEDVi increase ≤5 mL/m(2), RVEF decrease ≤3% and LVEF decrease ≤3%).
A total of 849 CMR studies in 339 patients (median age at first CMR 23.6 years) were analysed. Over a median interval of 2.2 years between CMR pairs, RVEDVi increased 4±18 mL/m(2) (p<0.001), RV end-systolic volume index increased 3±13 mL/m(2) (p<0.001), RVEF decreased 1%±6% (p=0.02) and LVEF decreased 1%±6% (p=0.001). Disease progression was observed in 15% (n=76) and non-progression in 26% (n=133). There were no significant differences between those with and without progression in baseline demographic, anatomic, ECG, exercise or baseline CMR characteristics. The optimal time interval between CMR studies for detection of progression was a 3-year interval (63% sensitivity, 65% specificity, area under the receiver operating characteristic curve 0.65).
Although progressive RV dilation and decline in biventricular systolic function occur at a slow pace in the majority of adults with repaired TOF, 15% of patients experience rapid disease progression. The results of this study support the practice of serial CMR examinations to identify progressive disease at a time interval of up to 3 years.
No preview · Article · Aug 2015 · Heart (British Cardiac Society)
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to determine outcomes in pregnant women with pre-existing coronary artery disease (CAD) or following an acute coronary syndrome (ACS) including myocardial infarction (MI).
The physiological changes of pregnancy can contribute to myocardial ischaemia. The pregnancy risk for women with pre-established CAD or a history of ACS/MI is not well studied.
This was a retrospective multicentre study. Adverse maternal cardiac, obstetric and fetal/neonatal events were examined. The primary outcome was a composite endpoint of cardiac arrest, ACS/MI, ventricular arrhythmia or congestive heart failure. The prevalence of new or progressive angina during pregnancy was also examined.
Fifty pregnancies in 43 women (mean age 35±5 years) were included. Coronary atherosclerosis (40%) and coronary thrombus (36%) were the most common underlying diagnoses. The primary outcome occurred in 10% (5/50) of pregnancies and included one maternal death secondary to cardiac arrest. Other events included ACS/MI (3/50) and heart failure (1/50). New or progressive angina occurred in 18% of pregnancies. Ischaemic complications of any type (new or progressive angina, ACS/MI, ventricular arrhythmia, cardiac arrest) occurred more commonly in women with coronary atherosclerosis compared with those without (50% vs 10%, p=0.003). A high rate of adverse obstetric (16%) and fetal/neonatal (30%) events was observed.
Pregnant women with pre-existing CAD or ACS/MI before pregnancy are at increased risk of adverse events during pregnancy. Those with coronary atherosclerosis are at highest risk of adverse maternal cardiac events due to myocardial ischaemia during pregnancy.
Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
No preview · Article · Jan 2015 · Heart (British Cardiac Society)
[Show abstract][Hide abstract] ABSTRACT: In adults with prior arterial switch operation (ASO) for d-transposition of the great arteries, the need for routine coronary artery assessment and evaluation for silent myocardial ischemia is not well defined. In this observational study we aimed to determine the value of a comprehensive cardiovascular magnetic resonance (CMR) protocol for the detection of coronary problems in adults with prior ASO for d-transposition of the great arteries.
Adult ASO patients (≥18 years of age) were recruited consecutively. Patients underwent a comprehensive stress perfusion CMR protocol that included measurement of biventricular systolic function, myocardial scar burden, coronary ostial assessment and myocardial perfusion during vasodilator stress by perfusion CMR. Single photon emission computed tomography (SPECT) was performed on the same day as a confirmatory second imaging modality. Stress studies were visually assessed for perfusion defects (qualitative analysis). Additionally, myocardial blood flow was quantitatively analysed from mid-ventricular perfusion CMR images. In unclear cases, CT coronary angiography or conventional angiography was done.
Twenty-seven adult ASO patients (mean age 23 years, 85% male, 67% with a usual coronary pattern; none with a prior coronary artery complication) were included in the study. CMR stress perfusion was normal in all 27 patients with no evidence of inducible perfusion defects. In 24 cases the coronary ostia could conclusively be demonstrated to be normal. There was disagreement between CMR and SPECT for visually-assessed perfusion defects in 54% of patients with most disagreement due to false positive SPECT.
Adult ASO survivors in this study had no CMR evidence of myocardial ischemia, scar or coronary ostial abnormality. Compared to SPECT, CMR provides additional valuable information about the coronary artery anatomy. The data shows that the asymptomatic and clinically stable adult ASO patient has a low pre-test probability for inducible ischemia. In this situation it is likely that routine evaluation with stress CMR is unnecessary.
Full-text · Article · Dec 2014 · Journal of Cardiovascular Magnetic Resonance
[Show abstract][Hide abstract] ABSTRACT: Rationale and Objectives
To investigate four-dimensional (4D) phase-contrast (PC) magnetic resonance (MR) in the evaluation of intracardiac shunts by simultaneous assessment of pulmonary (QP) and systemic (QS) flows in a pilot study and to compare results to through-plane two-dimensional (2D) PC MR.
Materials and Methods
Institutional review board approval and written informed consent were obtained. Nineteen patients with suspected intracardiac shunts underwent cardiac MR at 1.5T. Assessments of QP and QS were performed using free-breathing retrospectively gated 2D PC gradient recalled echo (GRE; 1.6 × 1.6 × 5 mm3) imaging with one-dimensional through-plane velocity encoding gradient (venc = 150 cm/s) in consecutive measurements for the main pulmonary artery (MPA) and ascending aorta (AA), respectively. A prospectively triggered 4D PC GRE technique (2.4 × 1.8 × 3 mm3) with three orthogonal venc directions was also used with volume coverage of both MPA and AA.
QP and QS assessed by 4D PC correlated with 2D PC acquisitions (r = 0.92 and r = 0.67 respectively; P < .0001 for both) but demonstrated significant underestimation of individual flow volumes (−21.9 ± 12.2 mL; P < .0001 and −10.7 ± 13.1 mL; P = .0023, respectively). Calculated QP:QS ratios demonstrated high correlation (r = 0.78; P < .0001) and no significant differences between 4D PC and 2D PC acquisitions (−0.09 ± 0.24, P = .14). Image acquisition times for 2D PC assessment of QP and QS were 2.98 ± 0.52 and 2.84 ± 0.50 minutes, respectively (P = .038), whereas time to acquire 4D PC images was significantly longer, 18.75 ± 4.58 minutes (P < .001).
Four-dimensional PC MR imaging allows for accurate assessment of QP:QS ratios in the evaluation of intracardiac shunts while absolute flow volumes demonstrate offsets. Further refinement of the technique with improvement in acquisition times may be required before widespread clinical implementation.
Full-text · Article · Aug 2014 · Academic Radiology
[Show abstract][Hide abstract] ABSTRACT: The 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.
• 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.
Full-text · Article · Jul 2014 · Insights into Imaging
[Show abstract][Hide abstract] ABSTRACT: Background
Chronic hemodynamically relevant pulmonary regurgitation (PR) resulting in important right ventricular (RV) dilation and ventricular dysfunction is commonly seen after tetralogy of Fallot (TOF) repair. Late adverse clinical outcomes, including exercise intolerance, arrhythmias, heart failure and/or death, accelerate in the third decade of life and are cause for considerable concern. Timing of pulmonary valve replacement (PVR) to address chronic PR is controversial, particularly in asymptomatic individuals, and impact of PVR on clinical measures has not been determined.
Canadian Outcomes Registry Late After Tetralogy of Fallot Repair (CORRELATE) is a prospective, multi-centre, Canada-wide cohort study. Candidates will be included if they are ≥12 years of age, have had surgically repaired TOF resulting in moderate or severe PR, and are able to undergo cardiovascular magnetic resonance imaging (CMR). Enrollment of >1000 individuals from 15 participating centres (Toronto, Montreal, Quebec City, Sherbrooke, Halifax, Calgary, Edmonton and Vancouver) is anticipated. Clinical data, health-related quality of life metrics and adverse outcomes will be entered into a web-based database. A central core lab will analyze all CMR studies (PR severity, RV volumes and ventricular function). Major adverse outcomes (sustained ventricular tachycardia and cardiovascular cause of death) will be centrally adjudicated.
CORRELATE will be the first prospective pan-Canadian cohort study of congenital heart disease in children and adults. CORRELATE will uniquely link clinical, imaging and functional data in those with repaired TOF and important PR, thereby enabling critical evaluation of clinically relevant outcomes in those managed conservatively as compared with those referred for PVR.
No preview · Article · Jun 2014 · The Canadian journal of cardiology
[Show abstract][Hide abstract] ABSTRACT: In women with valvular heart disease, pregnancy-associated cardiovascular changes can contribute to maternal, fetal, and neonatal complications. Ideally, a woman with valvular heart disease should receive preconception assessment and counselling from a cardiologist with expertise in pregnancy. For women with moderate- and high-risk valve lesions, appropriate risk stratification and management during pregnancy will optimise outcomes. Pregnancy in women with high-risk lesions, such as severe aortic stenosis, severe mitral stenosis, and those with mechanical valves, requires careful planning and coordination of antenatal care by a multidisciplinary team. The purpose of this overview is to describe the expected haemodynamic changes in pregnancy, review pregnancy risks for women with valvular heart disease, and discuss strategies for management.
No preview · Article · May 2014 · Best practice & research. Clinical obstetrics & gynaecology
[Show abstract][Hide abstract] ABSTRACT: The Fontan operation allows for longer survival of those born with functionally single ventricle physiology. Although it effectively eliminates cyanosis, increased systemic venous pressure is an unavoidable consequence and low cardiac output is frequent. The abdomen is particularly vulnerable to these alterations in hemodynamics because the hepatic blood flow consists predominantly of portal venous flow, which relies on a low pressure gradient between the portal and hepatic veins. Therefore, any subtle increase in systemic venous pressure will adversely affect the hemodynamic balance of the liver as well as the intestine. As the clinical manifestations and routine laboratory findings of abdominal complications can lag behind the hemodynamic and pathologic changes in the abdominal organs, regular imaging surveillance is critical. Magnetic resonance (MR) provides excellent visualization of both cardiovascular and abdominal systems. It provides robust anatomic and hemodynamic data which can be used for timely implementation of treatment options. In this review paper, we discuss the pathogenesis and MR findings of abdominal complications following the Fontan operation. Specifically we explore the utility of phase-contrast MR for assessment of the abdominal circulation in children following the Fontan palliation.
Full-text · Article · Apr 2014 · The international journal of cardiovascular imaging