Clinical trial NCT03249272
Conditions: Hypertrophic Cardiomyopathy Non-ischemic Dilated Cardiomyopathy Microvascular Ischaemia of Myocardium
Sponsor: Duke University
Start date: 2017-09-05; Completion date: 2019-03-31
Enrollment: 31 participants; Allocation: RANDOMIZED; Intervention model: PARALLEL

Brief summary:
The aim of this study is to assess microvascular function as determined by a cardiovascular magnetic resonance measurement of whole-heart (global) perfusion reserve. The goal is to determine the prevalence of MVD in two common forms of non-ischemic cardiomyopathy, hypertrophic cardiomyopathy (HCM) and idiopathic dilated cardiomyopathy (IDCM). The hypothesis that an optimized technique will provide robust detection of MVD and that a multifaceted approach will provide new insights into the pathophysiology of MVD, including the influence of myocardial scarring upon the presence and severity of MVD.

Detailed description:
Coronary microvascular dysfunction (MVD) has been implicated as an important marker of cardiac risk and has been thought to directly contribute to the pathogenesis of a wide variety of cardiomyopathies. For instance, MVD is believed to cause ischemia (with reduction in coronary flow reserve) in patients with hypertrophic cardiomyopathy (HCM) despite the presence of angiographically normal epicardial coronary arteries. The implication is that MVD in HCM may lead to the ventricular arrhythmias, sudden death, and heart failure. Similarly, patients with idiopathic dilated cardiomyopathy (IDCM) have blunted coronary flow reserve, which appears to be independently associated with poor prognosis.

Several etiologic mechanisms have been proposed to explain the occurrence of MVD, including structural and functional abnormalities1:

1. increased microvascular resistance due to reduced vascular luminal caliber.
2. reduced density of microvessels associated with replacement scarring.
3. inappropriate vasoconstrictor responses.
4. inadequate vasodilator responses.

Unfortunately, these mechanisms are difficult to study in humans since no technique currently allows the direct visualization of the coronary microcirculation in vivo. Thus, MVD has been largely studied using non-invasive imaging techniques, such as positron emission tomography (PET) or single photon emitted computed tomography (SPECT).

Although these methods have provided insight into MVD, much remains unknown. For example, even the prevalence of MVD in patients with various types of cardiomyopathy is unclear, with different studies showing widely different rates.

Cardiovascular magnetic resonance (CMR) is increasingly being used in clinical practice to evaluate cardiac disease. CMR employs a multifaceted imaging approach with separate techniques used to acquire separate sets of raw data, providing information on cardiac morphology, function, regional myocardial ischemia, scarring, and global myocardial perfusion reserve. The advantage of this approach is that image artifacts in one set of data will not affect the quality of the other datasets, and the datasets in combination can be used to distinguish separate pathophysiologies that could confound image interpretation. For example, perfusion defects could be due to ischemia or scar tissue, but since the investigators will obtain both perfusion images and scar images, the investigators will be able to resolve the etiology. Additionally, CMR provides high spatial resolution (over 10-fold higher than PET), and hence partial volume affects will be kept to a minimum and variability in measurements will be reduced.

The aim of this study is to assess microvascular function as determined by a cardiovascular magnetic resonance measurement of whole-heart (global) perfusion reserve. The goal is to determine the prevalence of MVD in two common forms of non-ischemic cardiomyopathy, hypertrophic cardiomyopathy (HCM) and idiopathic dilated cardiomyopathy (IDCM). The hypothesis that an optimized technique will provide robust detection of MVD and that a multifaceted approach will provide new insights into the pathophysiology of MVD, including the influence of myocardial scarring upon the presence and severity of MVD.

Arms: arm 1: None arm 2: None arm 3: None
Interventions: intervention 1: Regadenoson intervention 2: Adenosine
Intervention descriptions: intervention 1: Microvascular disease will be considered present if regional perfusion defects are observed or global perfusion reserve is reduced. For the assessment of microvascular disease, the adenosine and regadenoson groups will be combined, as the medications are considered interchangeable. intervention 2: Microvascular disease will be considered present if regional perfusion defects are observed or global perfusion reserve is reduced. For the assessment of microvascular disease, the adenosine and regadenoson groups will be combined, as the medications are considered interchangeable.

Protocol documents:
Prot_SAP_000.pdf: 
 
1
 
 
 
 
- Confidential – 
 
Version: 
 
 
3/01/2016  
 
 
 
 
                                     
Investigator Initiated Project Title: 
 
Microvascular Dysfunction in Nonischemic Cardiomyopathy: 
Insights From CMR Assessment of Coronary Flow Reserve 
 
Center: 
        
  
Duke Cardiovascular Magnetic Resonance Center,  
 
 
 
 
Division of Cardiology, Duke University Medical Center 
 
 
 
 
 
 
 
 
NCT03249272 
 
 
 
 
Investigators: 
 
Han W. Kim, MD 
 
Raymond J. Kim, MD 


 
2
Study Synopsis 
Study Title 
Microvascular dysfunction in nonischemic cardiomyopathy: Insights from CMR assessment of coronary flow 
reserve 
Primary 
Objective 
• To determine the prevalence of microvascular dysfunction (MVD) by a CMR measurement of whole-
heart (global) perfusion reserve in subtypes of nonischemic cardiomyopathy  
Secondary 
Objective 
• To compare the compare the CMR measurement of global perfusion reserve with regadenoson and 
adenosine  
• To ascertain the relationship between microvascular dysfunction and other CMR metrics including 
regional myocardial scarring and perfusion 
Study 
Design 
• Single-center, observational study 
Planned 
Enrollment 
• 30 patients with hypertrophic cardiomyopathy 
• 30 patients with idiopathic dilated cardiomyopathy 
• 15 controls with atypical chest pain 
Subject 
Selection 
Criteria 
Inclusion Criteria 
• Men or women aged 18 years or older 
• Cardiomyopathy patients 
         -Patients presenting for CMR with the clinical diagnosis of hypertrophic cardiomyopathy based 
on left ventricular wall thickness of at least ≥15 mm in the absence of any other cardiac or systemic 
cause of hypertrophy 
         -Patients presenting for CMR with the clinical diagnosis of idiopathic dilated cardiomyopathy 
based upon left ventricular ejection fraction ≤40%, LV end-diastolic diameter ≥55 mm or left 
ventricular end-systolic diameter ≤45 mm, and the absence of coronary stenoses on angiography. 
• Control patients with atypical chest pain 
              -Patients presenting for CMR evaluation of chest pain but without evidence of obstructive 
coronary artery disease either by coronary angiography or stress testing. 
Exclusion Criteria 
• 
Decompensated heart failure or hemodynamic instability 
• 
Prior coronary revascularization (PCI or CABG) or myocardial infarction (as evidenced by previously 
elevated CPK-MB or troponin levels)  
• 
Accelerating angina or unstable angina 
• 
Inability to physically tolerate MRI or implanted objects that are MRI incompatible 
• 
Inability to provide written informed consent obtained at time of study enrollment. 
• 
Severe claustrophobia 
• 
Advanced heart block or sinus node dysfunction 
• 
Hypersensitivity or allergic reaction to regadenoson or adenosine 
• 
Hypotension 
• 
Active bronchospasm or history of hospitalization due to bronchospasm 
• 
History of seizures 
• 
Recent cerebrovascular accident 
• 
Use of dipyridamole within the last 5 days 
• 
Contraindication to aminophylline 
• 
Severe renal insufficiency with estimated glomerular filtration rate <30 ml/min/ 1.73 m2 
• 
Pregnant or nursing 
 
Length of 
Study 
Projected duration of enrollment: 1-1.5 years 
Projected duration of analysis and manuscript preparation: 0.5-1 year 
Total study duration: ~2.5 years 
Primary 
Endpoint 
The primary endpoint will be the prevalence of MVD by CMR.  The hypothesis is that global perfusion 
reserve will be significantly lower in patients with hypertrophic cardiomyopathy and idiopathic dilated 
cardiomyopathy than in controls with atypical chest pain.  We also anticipate that differences in prevalence of 
MVD between the cardiomyopathy groups will be observed. 


 
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Secondary 
Endpoints 
The secondary endpoints will include 
• 
A comparison of CMR global perfusion reserve using regadenoson versus adenosine. 
• 
A comparison of the correlation coefficients between the extent of MVD and other CMR metrics, 
including myocardial scar size, extent of regional perfusion defects, and morphological and function 
characteristics such as LV mass, LVEF, and LV volume.   


 
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Scientific Rationale 
Coronary microvascular dysfunction (MVD) has been implicated as an important marker of cardiac 
risk and has been thought to directly contribute to the pathogenesis of a wide variety of 
cardiomyopathies.1,2 For instance, MVD is believed to cause ischemia (with reduction in coronary flow 
reserve) in patients with hypertrophic cardiomyopathy (HCM) despite the presence of angiographically 
normal epicardial coronary arteries. The implication is that MVD in HCM may lead to the ventricular 
arrhythmias, sudden death, and heart failure. Similarly, patients with idiopathic dilated 
cardiomyopathy (IDCM) have blunted coronary flow reserve, which appears to be independently 
associated with poor prognosis. 
Several etiologic mechanisms have been proposed to explain the occurrence of MVD, including 
structural and functional abnormalities1:  
(a) 
increased microvascular resistance due to reduced vascular luminal caliber. 
(b) 
reduced density of microvessels associated with replacement scarring. 
(c) 
inappropriate vasoconstrictor responses.  
(d) 
inadequate vasodilator responses. 
Unfortunately, these mechanisms are difficult to study in humans since no technique currently allows 
the direct visualization of the coronary microcirculation in vivo. Thus, MVD has been largely studied 
using non-invasive imaging techniques, such as positron emission tomography (PET) or single photon 
emitted computed tomography (SPECT).   
Although these methods have provided insight into MVD, much remains unknown. For example, even 
the prevalence of MVD in patients with various types of cardiomyopathy is unclear, with different 
studies showing widely different rates. In part, this may be due to limitations of these imaging 
methods.  For example, SPECT provides qualitative information regarding relative differences in 
regional blood flow, but is not able to assess global changes in myocardial blood flow. PET can 
quantify regional and global absolute blood flow, but these measurements may exhibit substantial 
variation in individual measurements depending upon the methodology that is employed (e.g. the 
arterial input function and/or the extraction model used).3  Both techniques can be affected by partial 
volume effects due to regional variation in LV wall thickness and the limited spatial resolution of 
imaging. Additionally, both PET and SPECT have difficulty distinguishing between reductions in 
blood flow due to ischemia versus scar tissue, which appears to be present in variable degrees 
depending on the type of cardiomyopathy.  Thus, the influence of scar tissue on myocardial blood flow 
in patients with suspected MVD is unknown. 
Cardiovascular magnetic resonance (CMR) is increasingly being used in clinical practice to evaluate 
cardiac disease.  CMR employs a multifaceted imaging approach with separate techniques used to 
acquire separate sets of raw data, providing information on cardiac morphology, function, regional 
myocardial ischemia, scarring, and global myocardial perfusion reserve.  The advantage of this 
approach is that image artifacts in one set of data will not affect the quality of the other datasets, and 
the datasets in combination can be used to distinguish separate pathophysiologies that could confound 
image interpretation.  For example, perfusion defects could be due to ischemia or scar tissue, but since 
we will obtain both perfusion images and scar images, we will be able to resolve the etiology. 
Additionally, CMR provides high spatial resolution (over 10-fold higher than PET), and hence partial 
volume affects will be kept to a minimum and variability in measurements will be reduced. 
 
In the proposed study, we will assess microvascular function as determined by a CMR measurement of 
whole-heart (global) perfusion reserve. Our laboratory has recently made optimizations to this 
technique (see below; Figure 1) which will improve the reproducibility of measurements. Our goal is 


 
5
to determine the prevalence of MVD in two common forms of non-ischemic cardiomyopathy, 
hypertrophic cardiomyopathy (HCM) and idiopathic dilated cardiomyopathy (IDCM).  We 
hypothesize that our optimized technique will provide robust detection of MVD and that our 
multifaceted approach will provide new insights into the pathophysiology of MVD, including the 
influence of myocardial scarring upon the presence and severity of MVD.  
 
The Duke Cardiovascular Magnetic Resonance Center (DCMRC) 
We believe the DCMRC is well positioned to successfully perform the proposed investigation.  The 
DCMRC was the first dedicated CMR clinical service in the United States, and is the largest.  We 
currently perform ~3,500 CMR scans per year, and of these, ~700 are stress perfusion CMR studies.  
The DCMRC also has an active research program.  Faculty members in the DCMRC developed and 
validated the delayed enhancement technique (DE-CMR), which is now utilized in all CMR centers 
worldwide to identify scar tissue associated with myocardial infarction and non-ischemic 
cardiomyopathy.4-10 Our group also published the first report describing how to combine stress 
perfusion CMR with delayed-enhancement CMR (DE-CMR) for differentiating ischemia from 
scar.11,12 
 
Pilot Data and Anticipated Findings 
As noted earlier in this proposal, we will use a multifaceted CMR imaging approach, which includes: 
(a) cine-CMR to assess left ventricular mass, volume, and function 
(b) coronary sinus velocity-flow CMR with and without vasodilator stress to measure global 
myocardial blood flow and perfusion reserve 
(c) first-pass perfusion CMR with and without vasodilator stress to evaluate regional perfusion 
defects 
(d) delayed enhancement CMR after contrast administration to provide high spatial resolution 
images of scar tissue. 
 
With regard to coronary sinus velocity-
flow CMR (CS-CMR), our group has 
recently introduced optimizations to this 
technique (Figure 1).  The optimizations 
are related to [a] sequence design (e.g. 
importance of water-fat in-phase 
measurement), [b] sequence settings (need 
for high bandwidth imaging), and [c] 
imaging protocol (e.g. precise double 
oblique plane needed within 1 cm of the 
origin of the coronary sinus). 
 
We have studied a small group of 
individuals with hypertrophic 
cardiomyopathy (n=5), idiopathic dilated 
cardiomyopathy (n=4), and normal 
controls (n=3).  These pilot data suggest that the optimizations reduce measurement variability and 
 
Figure 1.  Optimized CS-CMR demonstrating imaging planes 


 
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improve reproducibility compared with conventional imaging.  Additionally, we have observed several 
other interesting findings:  
 
(1) 
Global perfusion reserve by CS-CMR was often reduced in both patients with hypertrophic 
cardiomyopathy and idiopathic dilated cardiomyopathy (Figure 2, top). However, we also noted variability 
in the severity of MVD. For instance, in patients with HCM with mild LVH, borderline normal global 
perfusion reserve by CS-CMR was observed. In patients with IDCM, there seemed to be less dependence 
on LVH but a stronger relationship between the severity of LV systolic dysfunction and the severity of 
MVD.  
 
(2) 
We observed differences in MVD phenotype identified by CMR between patients with 
hypertrophic cardiomyopathy and idiopathic dilated cardiomyopathy.  An example is shown in 
Figure 2.  Although global perfusion was reduced to similar degrees in both, differences were clearly 
present on stress perfusion CMR and delayed enhancement CMR.  The patient with hypertrophic 
cardiomyopathy (Figure 2, left) demonstrated visible, focal perfusion defects on first-pass perfusion 
CMR and moderate scarring on delayed enhancement CMR.  The patient with idiopathic dilated 
cardiomyopathy (Figure 2, right) did not have any focal perfusion defects and scarring was minimal 
despite the same level of MVD (global perfusion reserve = 1.2 for both). 
 
One plausible explanation for this finding could be that MVD in hypertrophic cardiomyopathy is a 
result of abnormalities in arterioles, whereas in idiopathic dilated cardiomyopathy, the abnormalities 
may lie in the more distal microcirculation (e. g. due to capillary rarefaction). 
 
 
Figure 2.  Different MVD phenotype in hypertrophic cardiomyopathy (left) versus idiopathic dilated cardiomyopathy 
(right) identified by multifaceted CMR.  In both examples, there is evidence of severe MVD with markedly reduced 
global perfusion reserve by CS-CMR.  In HCM, regional perfusion defects by perfusion CMR (arrows) and extensive 
myocardial scarring by DE-CMR, (arrows), are also present. However, in idiopathic dilated cardiomyopathy, no 
regional perfusion defects are seen with only minimal scar. 


 
7
 
Hypothesis and Aims 
Primary Objective 
We propose to study the prevalence of MVD in patients with hypertrophic cardiomyopathy and idiopathic 
dilated cardiomyopathy compared to controls with atypical chest pain.  MVD will be assessed by CS-CMR 
and will be defined by presence of global perfusion reserve <2.0, which is a standard threshold used in prior 
studies.2 Based on our initial observations, we believe our measurement of MVD will clearly distinguish 
between patients with cardiomyopathy and control patients with atypical chest pain, who have normal 
coronary arteries and no evidence of ischemia. The prevalence of MVD will be greater than 50% for both 
HCM and IDCM, but will be different between patients with hypertrophic cardiomyopathy and idiopathic 
dilated cardiomyopathy.   
 
Secondary Objectives 
To demonstrate the generalizability of global perfusion reserve as measure of MVD, we will compare 
the CS-CMR measurement of global perfusion reserve with regadenoson versus that adenosine to 
demonstrate that they are similar. Specifically, the global perfusion reserve in all participants receiving 
regadenoson will be compared to those receiving adenosine using a two sample t-test. We will also 
explore whether differences within the subgroups are present (e.g. controls receiving regadenoson vs 
controls receiving adenosine; HCM patients receiving regadenoson vs HCM patients receiving 
adenosine;  IDCM patients receiving regadenoson vs IDCM receiving adenosine). However, given the 
relatively small numbers, we expect the within subgroup comparisons to be mainly for the generation 
of hypotheses for subsequent studies. 
 
 
Additionally, based on our initial observations, we anticipate that the presence and severity of MVD 
will be dependent on different morphological and functional characteristics in HCM and IDCM. 
Specifically we will examine: 
(1) the relationship between MVD and scarring 
(2) the relationship between MVD and regional perfusion defects 
(3) the relationship between MVD and LV morphologic characteristics (mass, volume, ejection 
fraction) 
As a tertiary objective, we will also estimate the amount of interstitial fibrosis present in the myocardium of 
patients HCM and IDCM, compared to controls.  Interstitial fibrosis will be estimated using MOdified 
Look-Locker Inversion-recovery sequence (MOLLI) sequence, which is performed prior to and after 
contrast administration.  We will attempt to discern if an association exists between MVD and increases in 
interstitial fibrosis.   
 
 
Methods 
Patient Selection  
We will recruit patients referred to the DCMRC with a documented history of hypertrophic cardiomyopathy 
or idiopathic dilated cardiomyopathy.  Those agreeing to consent will be enrolled and undergo the 
multifaceted CMR protocol (Figure 3).  Patients with history of coronary artery disease will be excluded. 
 
To serve as controls, we will recruit patients referred for CMR for atypical chest pain.  Only patients with 
low Framingham Risk (10% or less CHD risk at 10 years) and no history of CAD will be considered for 
recruitment.  Controls will be excluded if they have evidence of obstructive coronary artery disease either by 
coronary angiography or stress testing. 


 
8
 
Other Exclusion Criteria 
Patients will also be excluded for the following reasons: 
• 
Decompensated heart failure or hemodynamic instability 
• 
Prior coronary revascularization (PCI or CABG) or myocardial infarction (as evidenced by 
elevated CPK-MB or troponin levels)  
• 
Accelerating angina or unstable angina 
• 
Inability to physically tolerate MRI or implanted objects that are MRI incompatible 
• 
Inability to provide written informed consent obtained at time of study enrollment. 
• 
Severe claustrophobia 
• 
Advanced heart block or sinus node dysfunction 
• 
Hypersensitivity or allergic reaction to regadenoson or adenosine 
• 
Hypotension 
• 
Active bronchospasm or history of hospitalization due to bronchospasm 
• 
History of seizures 
• 
Recent cerebrovascular accident 
• 
Use of dipyridamole within the last 5 days 
• 
Contraindication to aminophylline 
• 
Hypersensitivity or allergic reaction to gadolinium contrast media 
• 
Severe renal insufficiency with estimated glomerular filtration rate <30 ml/min/ 1.73 m2 
• 
If they are pregnant or nursing 
 
A detailed clinical history will be performed in all patients at the time of CMR.  Information including age, 
gender, symptomatology, blood pressure, weight, height, and cardiac risk factors will be recorded.  12-lead 
ECGs will be obtained in all. Blood will be drawn for measurement of creatinine (point of care) and 
hematocrit. In women of childbearing potential, a serum HCG will be drawn. 
 
 
Study Specific Procedures 
Upon agreeing to participate in the study, subjects will be randomized to receive regadenoson or 
adenosine. 
 
CMR Overview 
The CMR methodology and analysis to be used are fully described 
in the references.  The entire scan procedure and scan time should 
take around 45 minutes.  A cardiologist or fellow will supervise 
the scan, assess/triage patients, and initiate treatment if needed. 
A schematic of the imaging procedure is shown in Figure 3. 
 
1. 
Standard Scout images of the heart leading to double 
oblique horizontal long axis view (4-Chamber) of the heart 
2. 
Cine Image of the horizontal long axis view of the heart 
3. 
Prescribed double oblique short axis view of the heart with 
first slice at the insertion points of the mitral valve in 
diastole. 
4. 
Cine images of the short axis of the left ventricle from the 
base to and including the apex for entire LV coverage. 
 
Figure 3.  Multifaceted CMR examination 


 
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5. 
Cine images of the long axis views of the heart (2 chamber, 3 chamber, 4 chamber). 
6. 
MOLLI images will be obtained prior contrast administration. 
7. 
Coronary sinus imaging at rest as described in Figure 1.  
8. 
Patients and controls will receive either (a) regadenoson (0.4 mg IV) injection over 10 seconds 
followed by saline flush or (b) adenosine 140 μg·kg-1·min-1 x 3 minutes.  During the injection 
or infusion, the participants will be monitored (continuous ECG and blood pressure 
monitoring) for 3-4 minutes.  Half of the participants will receive Regadenoson, while the 
remainder will receive adenosine.  Any serious adverse reactions during or after vasodilator 
stress will be recorded. 
9. 
Stress perfusion images of 4-5 short axis slices (basal, mid, and apical) per heart beat for 60 
heart beats beginning after 1-1.5 minutes after the regadenoson injection. 
10. 
Bolus contrast injection of 0.1 mmol/kg of gadolinium contrast (gadoteridol or gadoteric acid) 
followed at 30 cc of saline flush beginning beginning after 1-1.5 minutes after regadenoson 
administration or after 2 minutes of adenosine infusion. 
11. 
Coronary sinus imaging during stress (Figure 1). 
12. 
In those receiving regadenoson, aminophylline (100 mg IV) will be administered over 30-60 
seconds after completion of coronary sinus imaging.  If bronchospasm is noted, participants 
will be treated with inhaled albuterol metered dose inhaler. 
13. 
After a 15 minutes wait period, rest perfusion images of 4-5 short axis slices per heart beat for 
60 heart beats using the identical imaging location and parameters as the stress perfusion 
images. 
14. 
Bolus contrast injection of 0.1 mmol/kg of gadolinium contrast (gadoteridol or gadoteric acid) 
followed at 30 cc of saline flush beginning at the start of rest perfusion imaging. 
15. 
Delayed enhancement images  
a. (Starting immediately after rest perfusion imaging) True FISP IR single shot non-breath held 
images (stack of short-axis views from base to apex with normal myocardium nulled).  These 
are performed with the patient instructed to breath quietly with minimal respiratory motion 
b.  (Starting immediately after single shot True FISP IR) breath held, ECG gated, segmented 
inversion recovery FLASH sequence with inversion time adjusted to null the myocardium.  
Slice locations should be identical to cine CMR locations 
c. Repeat step A (single-shot non breath-held stack of delayed enhancement images) with the TI 
fixed at 600 ms.  
 
16. 
MOLLI images will be obtained after contrast administration. 
 
CMR details and parameters 
(1) Cine:  
• SSFP cine sequences are ECG gated and breath held 
• Slice Thickness of 6mm with a distance of 8 mm between slices (gap of 2 mm) 
• Temporal resolution of less than 45 ms 
• Flip angle maximized (>60 degrees) 
• After obtaining horizontal long axis of the heart, obtain double oblique short axis at the level of 


 
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the insertion points of the mitral valve in diastole.  Proceed with short axis cines every 10mm 
from the base to the apex until the myocardium is not visualized 
 
(2) Coronary sinus at rest 
A 3 step process was used to determine the optimal view for en face velocity encoded CMR of the CS. 
A graphical demonstration of the steps is shown in Figure 1A-B. 
• Step 1: Acquisition of optimal CS-CMR imaging plane (Figure 1).  In addition to the standard 
long axis cine planes, 2 additional orthogonal views (diaphragmatic 4-chamber, basal short-
axis) are obtained to localize the coronary sinus. The diaphragmatic 4-chamber is obtained by 
adjusting the standard 4-chamber, inferiorly to visualize the CS entering into RA.  A basal 
short axis is obtained based upon the location of the CS on the diaphragmatic 4-chamber.  The 
optimal CS-CMR plane was acquired orthogonal to the CS in both in-plane views, within 1-2 
cm of the CS ostium, ensuring the through-plane CS perpendicular to the main direction of the 
CS motion. 
• Step 2: To obtain CS flow data, a velocity encoded CMR sequence to image en-face CS flow.  
The CS is centered with small field of view such that the CS is at the iso-center of the magnet 
for the reduction of velocity offset errors (Rolf, JCMR 2011,13:18). The small field of view is 
adapted to patient body size (Figure 1A right panel). 
• Step 3: Optimize CS-CMR sequence parameters.  The velocity encoded CMR sequence is 
performed with “whisper” gradients.  The maximum gradient amplitude is minimized at < 22 
(mT/meter).  The slew rate of bipolar gradient is also minimized to  < 50 mT/mms in order  to 
reduce eddy currents and maxwell terms. (Figure 1B, left panel). CS-CMR images are then 
acquired at rest using a breath-hold retrospective triggered gradient-echo sequence.  Summary 
of sequence parameters are listed below:  
a) For 3.0T: TR/TE, 5.2/2.5 ms; temporal resolution: 31.3ms; For 1.5T: TR/TE, 7.4/4.8 ms; 
temporal resolution: 44.5ms; 3 lines per segment, flip angle, 20°; section thickness, 10 
mm; field of view;  
b) The velocity encoding was set to a maximum velocity of 70-90 cm/sec and set higher if 
there is aliasing. 
c) The contour of the cross-sectioned CS was traced base on both anatomic and flow cine 
images at each time frame. CS blood flow (ml/sec) was calculated by summing the flow 
per cardiac phase over the cardiac cycle. 
 
(3) Stress Perfusion 
• Saturation-recovery non-segmented imaging with GRE readout 
• Short-axis view imaging (at least 4 slices / per heart beat) 
• Slice thickness 6-8 mm 
• Parallel imaging, 2-fold acceleration 
• In-plane resolution, ~ 1.8-2.8 x 2.0 mm 
• Temporal resolution ~ 100 – 125 ms 
• Regadenoson (0.4 mg IV) injection over 10 seconds followed by saline flush under continuous 
ECG and blood pressure monitoring for 3-4 minutes while patient table is partially outside of 
bore for easy patient monitoring OR 
• Adenosine (140 μg·kg-1·min-1) infusion under continuous ECG and blood pressure monitoring 
for 3-4 minutes while patient table is partially outside of bore for easy patient monitoring 
• Patient table is pushed in and then contrast is given (0.075 – 0.1 mmol/kg, 3-5 ml/sec) followed 


 
11
by at least 30 ml saline flush (3-5 ml/sec) 
• After imaging for 40-50 heart beats by which time contrast has transited the LV myocardium. 
 
(4) Coronary sinus during adenosine stress immediately following stress perfusion imaging. 
• So that global perfusion reserve can be calculated, imaging will be performed at the identical 
location and parameters as with CS-CMR at rest. 
• In those receiving regadenoson, aminophylline (100 mg IV) will be administered over 30-60 
seconds after completion of coronary sinus imaging. 
 
(5) Rest Perfusion 
• After  ~15 minute wait for contrast to washout from stress perfusion imaging, perfusion 
imaging repeated without pharmacologic stress using same dose of gadolinium contrast 
 
(6) Delayed Enhancement MRI (single-shot non breathheld): 
• SSFP Single Shot ECG-triggered non-breath held inversion recovery sequence (short-axis stack 
from base to apex) with appropriate inversion time to null the myocardium 
• Flip angle is 45 degrees, matrix size is 192 in frequency encode direction. 
• Data acquisition is centered in mid-diastole 
• Slice Thickness of 6mm with a distance of 8 mm between slices (gap of 2 mm) 
• Images are acquired with triggering set to every third or fourth heart beat to allow recovery of 
relaxation between slices. 
(7) Delayed Enhancement Images (segmented breathheld): 
• ECG-gated breath hold segmented inversion-recovery GRE sequence with inversion time 
adjusted to null signal in normal myocardium.  
• Temporal resolution should be below 200 ms 
• Flip angle should be 25 degrees 
• TE should be 3-4 msec and TR should be 8-9 msec 
• Slice locations should be identical to cine MRI locations (6-8 short axis, 2- and 4-chamber long 
axis) with slice thickness of 6 mm. The field of view should be set to the minimum possible 
without fold-in artifact obscuring the left ventricle. Timing is set to acquire image data in mid-
diastole.  Typical voxel is 1.9 X 1.4 X 6 cm. 
(8) MOLLI images 
• SSFP ECG-gated, breathheld in three short axis location performed prior to contrast and after 
gadolinium contrast administration 
• Flip angle is 45 degrees. 
• Data acquisition is centered in mid-diastole 
• Pre contrast images will be obtained using 2 inversion recovery pulses followed by 5 and 3 
readout heartbeats respectively, separated by 3 wait heartbeats. 
• Post contrast images will be obtained using 3 inversion recovery pulses followed by 4, 3, and 2 
readout heartbeats with an extra heartbeat between inversions. 
 
 


 
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Image Analysis 
For the primary aim of the study, the prevalence of MVD will be determined by the measurement of 
global perfusion reserve.  Global preserve reserve is calculated from the following formula: 
 
Global Perfusion Reserve = 
coronary sinus blood flow during maximal vasodilation 
coronary sinus blood flow at rest
 
 
Coronary sinus blood flow will be measured by contouring the coronary sinus at each time point within 
the cardiac cycle on both the magnitude and phase CS-CMR images at each cardiac frame.  Total 
coronary sinus blood flow is then calculated by summing the flow per cardiac frame over the cardiac 
cycle. A global perfusion reserve of <2.0 will be regarded as abnormal and consistent with MVD. 
 
Flow measurements will undergo a baseline correction using basal myocardium reference region 
located closest to the coronary sinus during at late-systole or mid-diastole when the motion is the most 
static.  The baseline correction was performed for each cardiac frame to get the corrected coronary 
sinus blood flow. Coronary sinus blood flowcorr=Vcorr×ACS, where coronary sinus blood flowcorr is 
baseline corrected. Vcorr comes from subtracting mean velocity of static region of interest from CS 
velocities. ACS is area of CS at each time frame.  
 
For the secondary aims, specific analyses will also be performed for each CMR technique to determine 
myocardial scar size, extent of regional perfusion defects, and morphological and function 
characteristics such as LV mass, LVEF, and LV volume.   
 
Myocardial scarring will be determined by visual inspection using the American Heart Association 17-
segment model. A patient is adjudicated to have myocardial scarring if there is at least more than one 
quarter of a myocardial segment of DE.  This is done to reduce the effect of imaging artifacts, which 
can occasionally mimic DE.  The extent of regional scarring is scored according to the spatial extent of 
delayed hyperenhancement within each segment (0 = no hyperenhancement (HE); 1 = 1%–25% HE; 2 
= 26%–50% HE; 3 = 51%–75% HE; and 4 = 76%–100% HE). Global infarct size will be calculated by 
contouring of hyperenhanced regions from the stack of short-axis of delayed enhancement CMR 
images. 
 
Regional myocardial perfusion will be scored by visual inspection using the American Heart 
Association 17-segment model (minus the apex) for the presence or absence of perfusion abnormalities 
and the spatial extent of hypoperfusion within each segment.  Perfusion defect size will be be 
calculated by contouring of hypoenhanced regions from stress perfusion CMR images. 
 
For calculation of left ventricular mass, volume, and ejection fraction, endocardial borders on the stack 
of short-axis cine images in end diastole and end systole, and the epicardial borders in end diastole, 
will be traced using planimetry. End diastolic volume (EDV) and end systolic volume (ESV) are 
calculated from the product of the area end-diastole and end systole respectively and the thickness of 
the imaged slice (10 mm). Left ventricular ejection fraction (LVEF) is calculated using the following 
formula: 
 
LVEF = 
end diastolic volume − end systolic volume 
end diastolic volume 
 
 
Left ventricular mass is calculated by subtracting endocardial from epicardial volumes and multiplying 
by myocardial density (1.05 g/cm3).  
 


 
13
The amount of interstitial fibrosis will be estimated by calculating the extracellular volume fraction 
from the MOLLI images. 
 
The myocardial extracellular volume fraction (ECF) is calculated from the following formula: 
 
 
 
 
 
ECFmyo = [1 – hematocrit] * ΔR1myo / ΔR1blood 
 
where ΔR1 = (R1post-contrast) - (R1pre-contrast) for myocardium or blood, respectively, and R1 = 1/T1.  ECF 
values above that of a normal population are considered abnormal (elevated) and are inferred to 
represent increased fibrosis. 
 
All image analyses will be performed blinded to patient identity and clinical characteristics. 
 
 
Statistical Methods 
Sample size Determination 
The determination of sample size is based upon the primary aim of the study to assess the prevalence 
of MVD in subtypes of cardiomyopathy. Using a cutoff value of >2.0 as normal for global perfusion 
reserve, our pilot data demonstrates that MVD is present in approximately 70% patients with HCM, 
whereas none of the 3 controls had MVD. Samples sizes of 25 in each group (HCM and IDCM) will 
provide 71% power to detect a difference of 25% in the presence of MVD at α=0.05.  
 
 
Expected Start Date / Length of Enrollment 
Immediate start date once protocol is approved. Given rate of enrollment of pilot data, we anticipate 
enrollment will be completed in 12-18 months. 
 
 
Data Handling and Record Keeping 
Data will be stored securely under the patient’s name.  All clinical data, images and procedural data 
will be de-identified prior to any in-house or public presentation of data or images. Coded data will 
only be released to those listed as study investigators or support staff.  Clinical CMR images will be 
stored in the clinical PACS system of the Cardiac Magnetic Resonance Imaging Center (WebPAX, 
Heart Imaging Technologies, LLC www.heartit.com) system.  All electronic research data will be 
stored on Duke School of Medicine servers on a secured shared drive in a database that is only 
accessible to the research team.  The principal investigator, sub-investigators, study research 
coordinators, regulatory personnel, Duke University Medical Center Institutional Review Board, and 
any applicable regulatory agencies will have access to the study records.  The data and associated 
identifiers will be kept for up to 6 years in a locked research facility accessible only to designated 
personnel, at which time the data will be destroyed. 
 
 
Serious Adverse Events Reporting 
A cardiologist or fellow will supervise the scan, assess/triage patients, and initiate treatment if needed. 
A serious adverse event will be defined as any untoward medical occurrence that: 
(1) Results in death. 
(2) Is life-threatening.  Any adverse experience that places the subject, in the view of the 
investigator, at immediate risk of death from the reaction as it occurred (i.e., it does not include 
a reaction that, had it occurred in a more serious form, might have caused death). 


 
14
(3) Requires inpatient hospitalization or prolongation of existing hospitalization. 
(4) Results in persistent or significant disability or incapacity. 
(5) Is a congenital anomaly/birth defect. 
(6) An event that required intervention to prevent permanent impairment or damage or is 
considered medically important. 
 
All adverse events will be reported to the Duke Institutional Review Board, as follows  
(1) Immediately (within 24 hours) upon learning of an unanticipated study-related death, study 
personnel will notify the IRB and provide a brief summary of the event. Then, within 1 week 
(five business days), study personnel will send to the IRB a formal safety event submission. 
(2) For a reportable serious adverse event, study personnel will notify the IRB within five business 
days of the investigator becoming aware of the event. Study personnel will send a formal safety 
event submission. 
(3) For any other problem or event requiring prompt reporting to the IRB, within ten business days 
of the investigator becoming aware of the event, study personnel will send to the IRB a formal 
safety event submission. 
 
Any serious adverse events will also be reported to the Federal Drug Administration through the 
MedWatch program at the time that the IRB is notified. A copy will also be provided to Astellas 
Pharma, Inc.  
 


 
15
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