Microvascular Dysfunction in Nonischemic Cardiomyopathy: Insights From CMR Assessment of Coronary Flow Reserve

• Sponsor: Duke University (Other)
• Overall Status: Terminated
• CT.gov ID: NCT03249272
• Collaborator: (none)
• Enrollment: 31
• Location: 1
• Arms: 3
• Actual Duration (Months): 18.8
• Patients Per Site Per Month: 1.6

Study Details

Study Description

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.

Condition or Disease	Intervention/Treatment	Phase
Hypertrophic Cardiomyopathy; Non-ischemic Dilated Cardiomyopathy; Microvascular Ischaemia of Myocardium	Drug: Regadenoson; Drug: Adenosine	Phase 4

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.

Study Design

• Study Type: Interventional
• Actual Enrollment: 31 participants
• Allocation: Randomized
• Intervention Model: Parallel Assignment
• Intervention Model Description: Participants undergoing cardiovascular magnetic resonance stress testing will be recruited and randomized to receive either regadenoson or adenosine.Participants undergoing cardiovascular magnetic resonance stress testing will be recruited and randomized to receive either regadenoson or adenosine.
• Masking: Single (Outcomes Assessor)
• Masking Description: The reader of the CMR scan will be blinded to the stress agent used.
• Primary Purpose: Basic Science
• Official Title: Microvascular Dysfunction in Nonischemic Cardiomyopathy: Insights From CMR Assessment of Coronary Flow Reserve
• Actual Study Start Date: Sep 5, 2017
• Actual Primary Completion Date: Mar 31, 2019
• Actual Study Completion Date: Mar 31, 2019

Arms and Interventions

Arm	Intervention/Treatment
Active Comparator: Hypertrophic cardiomyopathy	Drug: Regadenoson; 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.; Drug: Adenosine; 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.
Active Comparator: Non-ischemic dilated cardiomyopathy	Drug: Regadenoson; 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.; Drug: Adenosine; 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.
Active Comparator: Control	Drug: Regadenoson; 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.; Drug: Adenosine; 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.

Outcome Measures

Primary Outcome Measures

1. Prevalence of Microvascular Dysfunction (MVD) by a CMR Measurement of Whole-heart (Global) Perfusion Reserve Ratio in Patients With Hypertrophic Cardiomyopathy, Non-ischemic Cardiomyopathy, and Controls. [The prevalence of MVD will be determined based on the findings at the time of the scan on Day 1 of the study.]

   Prevalence of microvascular dysfunction as determined by the CMR measure of global perfusion reserve ratio (GPR) in each these patient groups. MVD was considered present when either GPR was <2.0 or regional stress perfusion abnormalities were present. In order to calculate this ratio, coronary sinus flow was measured twice: prior to the the administration of adenosine/regadenoson during the administration of adenosine/regadenoson GPR is a ratio of coronary sinus flow during the administration adenosine/regadenoson divided by the baseline coronary sinus flow measured prior to the administration. Regional perfusion abnormalities will be assessed at the time of adenosine/regadenoson administration.

Secondary Outcome Measures

1. CMR Measurement of Global Perfusion Reserve Ratio [The global perfusion ratio will be calculated from the measurements obtained at the time of the scan on Day 1 of the study.]

   Comparison of the CMR measure of global perfusion reserve ratio (GPR) in each these patient groups. In order to calculate this ratio, coronary sinus flow was measured twice: prior to the the administration of adenosine/regadenoson during the administration of adenosine/regadenoson

2. The Association Between Global Perfusion Reserve (GPR) Ratio and Regional Myocardial Scarring. [Both global perfusion ratio and the presence of regional scarring will be determined/measured from the images obtained during the scan on Day 1 of the study.]

   Relationship between global perfusion reserve ratio and regional myocardial scarring.

Eligibility Criteria

Criteria

• Ages Eligible for Study: 18 Years and Older
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: No

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

• Patients presenting for CMR 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

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Duke Cardiovascular Magnetic Resonance Center	Durham	North Carolina	United States	27110

Sponsors and Collaborators

• Duke University

Investigators

• Principal Investigator: Han Kim, Duke University

Study Documents (Full-Text)

• Study Protocol and Statistical Analysis Plan - Mar 1, 2016

More Information

Publications

• Camici PG, Crea F. Coronary microvascular dysfunction. N Engl J Med. 2007 Feb 22;356(8):830-40. Review.
• Camici PG, d'Amati G, Rimoldi O. Coronary microvascular dysfunction: mechanisms and functional assessment. Nat Rev Cardiol. 2015 Jan;12(1):48-62. doi: 10.1038/nrcardio.2014.160. Epub 2014 Oct 14. Review.
• Choudhury L, Mahrholdt H, Wagner A, Choi KM, Elliott MD, Klocke FJ, Bonow RO, Judd RM, Kim RJ. Myocardial scarring in asymptomatic or mildly symptomatic patients with hypertrophic cardiomyopathy. J Am Coll Cardiol. 2002 Dec 18;40(12):2156-64.
• Klem I, Greulich S, Heitner JF, Kim H, Vogelsberg H, Kispert EM, Ambati SR, Bruch C, Parker M, Judd RM, Kim RJ, Sechtem U. Value of cardiovascular magnetic resonance stress perfusion testing for the detection of coronary artery disease in women. JACC Cardiovasc Imaging. 2008 Jul;1(4):436-45. doi: 10.1016/j.jcmg.2008.03.010.
• Klem I, Heitner JF, Shah DJ, Sketch MH Jr, Behar V, Weinsaft J, Cawley P, Parker M, Elliott M, Judd RM, Kim RJ. Improved detection of coronary artery disease by stress perfusion cardiovascular magnetic resonance with the use of delayed enhancement infarction imaging. J Am Coll Cardiol. 2006 Apr 18;47(8):1630-8. Epub 2006 Mar 27.

• Responsible Party: Duke University
• ClinicalTrials.gov Identifier: NCT03249272
• Other Study ID Numbers: Pro00082447
• First Posted: Aug 15, 2017
• Last Update Posted: Sep 16, 2020
• Last Verified: Aug 1, 2020

• Individual Participant Data (IPD) Sharing Statement: Undecided
• Plan to Share IPD: Undecided
• Studies a U.S. FDA-regulated Drug Product: Yes
• Studies a U.S. FDA-regulated Device Product: No
• Product Manufactured in and Exported from the U.S.: No
• Additional relevant MeSH terms: Cardiomyopathies; Cardiomyopathy, Hypertrophic; Cardiomyopathy, Dilated; Ischemia; Adenosine; Regadenoson

Study Results

Participant Flow

Pre-assignment Detail	Due to the slow pace of recruitment, the sponsor withdrew funding for the study. Of the expected 75 participants, 31 were recruited. As was pre-specified, the regadenoson and adenosine groups were combined for analysis as these interventions are interchangeable.

Arm/Group Title	Hypertrophic Cardiomyopathy	Non-ischemic Dilated Cardiomyopathy	Control
Arm/Group Description	Microvascular dysfunction (MVD) will be categorized as present based upon the presence of one of the following: Global perfusion reserve (GPR) < 2.0. Coronary sinus blood flow (CS) with velocity-encoded CMR will be measured during maximal vasodilation and at rest. GPR was calculated as the ratio of stress CS to rest CS blood flow. The presence of regional perfusion abnormalities on visual assessment of first pass perfusion images. For the analysis of the global perfusion ratio, the regadenson and adenosine groups were combined. The prevalence will be calculated by dividing the number of hypertrophic cardiomyopathy patients with MVD by the total number of patients with hypertrophic cardiomyopathy.	Microvascular dysfunction (MVD) will be categorized as present based upon the presence of one of the following: Global perfusion reserve (GPR) < 2.0. Coronary sinus blood flow (CS) with velocity-encoded CMR will be measured during maximal vasodilation and at rest. GPR was calculated as the ratio of stress CS to rest CS blood flow. The presence of regional perfusion abnormalities on visual assessment of first pass perfusion images. For the analysis of the global perfusion ratio, the regadenson and adenosine groups were combined. The prevalence will be calculated by dividing the number of non-ischemic dilated cardiomyopathy patients with MVD by the total number of patients with non-ischemic dilated cardiomyopathy.	Microvascular dysfunction (MVD) will be categorized as present based upon the presence of one of the following: Global perfusion reserve (GPR) < 2.0. Coronary sinus blood flow (CS) with velocity-encoded CMR will be measured during maximal vasodilation and at rest. GPR was calculated as the ratio of stress CS to rest CS blood flow. The presence of regional perfusion abnormalities on visual assessment of first pass perfusion images. For the analysis of the global perfusion ratio, the regadenson and adenosine groups were combined. The prevalence will be calculated by dividing the number of control patients with MVD by the total number of control patients.
Period Title: Overall Study
STARTED	19	6	6
COMPLETED	19	6	6
NOT COMPLETED	0	0	0

Baseline Characteristics

Arm/Group Title	Hypertrophic Cardiomyopathy	Non-ischemic Dilated Cardiomyopathy	Control Patients	Total
Arm/Group Description	Microvascular dysfunction (MVD) will be categorized as present based upon the presence of one of the following: Global perfusion reserve (GPR) < 2.0. Coronary sinus blood flow (CS) with velocity-encoded CMR will be measured during maximal vasodilation and at rest. GPR was calculated as the ratio of stress CS to rest CS blood flow. The presence of regional perfusion abnormalities on visual assessment of first pass perfusion images. The prevalence will be calculated by dividing the number of hypertrophic cardiomyopathy patients with MVD by the total number of patients with hypertrophic cardiomyopathy.	Microvascular dysfunction (MVD) will be categorized as present based upon the presence of one of the following: Global perfusion reserve (GPR) < 2.0. Coronary sinus blood flow (CS) with velocity-encoded CMR will be measured during maximal vasodilation and at rest. GPR was calculated as the ratio of stress CS to rest CS blood flow. The presence of regional perfusion abnormalities on visual assessment of first pass perfusion images. The prevalence will be calculated by dividing the number of non-ischemic dilated cardiomyopathy patients with MVD by the total number of patients with non-ischemic dilated cardiomyopathy.	Microvascular dysfunction (MVD) will be categorized as present based upon the presence of one of the following: Global perfusion reserve (GPR) < 2.0. Coronary sinus blood flow (CS) with velocity-encoded CMR will be measured during maximal vasodilation and at rest. GPR was calculated as the ratio of stress CS to rest CS blood flow. The presence of regional perfusion abnormalities on visual assessment of first pass perfusion images. The prevalence will be calculated by dividing the number of control patients with MVD by the total number of control patients.	Total of all reporting groups
Overall Participants	19	6	6	31
Age (years) [Mean (Standard Deviation) ]
Mean (Standard Deviation) [years]	46.1 (17.7)	60.6 (12.2)	53.2 (5.7)	50.3 (15.9)
Sex: Female, Male (Count of Participants)
Female	5 26.3%	2 33.3%	5 83.3%	12 38.7%
Male	14 73.7%	4 66.7%	1 16.7%	19 61.3%
Race (NIH/OMB) (Count of Participants)
American Indian or Alaska Native	0 0%	0 0%	0 0%	0 0%
Asian	1 5.3%	0 0%	0 0%	1 3.2%
Native Hawaiian or Other Pacific Islander	0 0%	0 0%	0 0%	0 0%
Black or African American	2 10.5%	1 16.7%	1 16.7%	4 12.9%
White	16 84.2%	5 83.3%	5 83.3%	26 83.9%
More than one race	0 0%	0 0%	0 0%	0 0%
Unknown or Not Reported	0 0%	0 0%	0 0%	0 0%
Region of Enrollment (Count of Participants)
United States	19 100%	5 83.3%	6 100%	30 96.8%

Outcome Measures

1. Primary Outcome

Title	Prevalence of Microvascular Dysfunction (MVD) by a CMR Measurement of Whole-heart (Global) Perfusion Reserve Ratio in Patients With Hypertrophic Cardiomyopathy, Non-ischemic Cardiomyopathy, and Controls.
Description	Prevalence of microvascular dysfunction as determined by the CMR measure of global perfusion reserve ratio (GPR) in each these patient groups. MVD was considered present when either GPR was <2.0 or regional stress perfusion abnormalities were present. In order to calculate this ratio, coronary sinus flow was measured twice: prior to the the administration of adenosine/regadenoson during the administration of adenosine/regadenoson GPR is a ratio of coronary sinus flow during the administration adenosine/regadenoson divided by the baseline coronary sinus flow measured prior to the administration. Regional perfusion abnormalities will be assessed at the time of adenosine/regadenoson administration.
Time Frame	The prevalence of MVD will be determined based on the findings at the time of the scan on Day 1 of the study.

Outcome Measure Data

Analysis Population Description

Due to the slow pace of recruitment, the sponsor withdrew funding for the study. Of the expected 75 participants, 31 were recruited. As was pre-specified, the regadenoson and adenosine groups were combined for analysis as these interventions are interchangeable.

Arm/Group Title	Hypertrophic Cardiomyopathy	Non-ischemic Dilated Cardiomyopathy	Control
Arm/Group Description	Microvascular dysfunction (MVD) will be categorized as present based upon the presence of one of the following: Global perfusion reserve (GPR) < 2.0. Coronary sinus blood flow (CS) with velocity-encoded CMR will be measured during maximal vasodilation and at rest. GPR was calculated as the ratio of stress CS to rest CS blood flow. The presence of regional perfusion abnormalities on visual assessment of first pass perfusion images. The prevalence will be calculated by dividing the number of hypertrophic cardiomyopathy patients with MVD by the total number of patients with hypertrophic cardiomyopathy.	Microvascular dysfunction (MVD) will be categorized as present based upon the presence of one of the following: Global perfusion reserve (GPR) < 2.0. Coronary sinus blood flow (CS) with velocity-encoded CMR will be measured during maximal vasodilation and at rest. GPR was calculated as the ratio of stress CS to rest CS blood flow. The presence of regional perfusion abnormalities on visual assessment of first pass perfusion images. The prevalence will be calculated by dividing the number of non-ischemic dilated cardiomyopathy patients with MVD by the total number of patients with non-ischemic dilated cardiomyopathy.	Microvascular dysfunction (MVD) will be categorized as present based upon the presence of one of the following: Global perfusion reserve (GPR) < 2.0. Coronary sinus blood flow (CS) with velocity-encoded CMR will be measured during maximal vasodilation and at rest. GPR was calculated as the ratio of stress CS to rest CS blood flow. The presence of regional perfusion abnormalities on visual assessment of first pass perfusion images. The prevalence will be calculated by dividing the number of control patients with MVD by the total number of control patients.
Measure Participants	19	6	5
Number [Percentage of group with MVD]	79	33.3	20

2. Secondary Outcome

Title	CMR Measurement of Global Perfusion Reserve Ratio
Description	Comparison of the CMR measure of global perfusion reserve ratio (GPR) in each these patient groups. In order to calculate this ratio, coronary sinus flow was measured twice: prior to the the administration of adenosine/regadenoson during the administration of adenosine/regadenoson
Time Frame	The global perfusion ratio will be calculated from the measurements obtained at the time of the scan on Day 1 of the study.

Outcome Measure Data

Analysis Population Description

As was pre-specified, the regadenoson and adenosine groups were combined for analysis as these interventions are interchangeable.

Arm/Group Title	Hypertrophic Cardiomyopathy	Non-ischemic Dilated Cardiomyopathy	Control
Arm/Group Description	Global perfusion reserve	Global perfusion reserve	Global perfusion reserve
Measure Participants	19	6	5
Median (Inter-Quartile Range) [ratio]	2.99	3.04	3.83

3. Secondary Outcome

Title	The Association Between Global Perfusion Reserve (GPR) Ratio and Regional Myocardial Scarring.
Description	Relationship between global perfusion reserve ratio and regional myocardial scarring.
Time Frame	Both global perfusion ratio and the presence of regional scarring will be determined/measured from the images obtained during the scan on Day 1 of the study.

Outcome Measure Data

Analysis Population Description

As was pre-specified, the regadenoson and adenosine groups were combined for analysis as these interventions are interchangeable. One of the control patients was not able to hold his/her breath, and no image was acquired for stress perfusion myocardial flow. Thus, global perfusion reserve could not be calculated.

Arm/Group Title	Hypertrophic Cardiomyopathy - Scarring	Hypertrophic Cardiomyopathy - Without Scarring	Non-ischemic Dilated Cardiomyopathy - Scarring	Non-ischemic Dilated Cardiomyopathy - Without Scarring	Control - Scarring	Control - Without Scarring
Arm/Group Description	Mean value of all patients with Hypertrophic cardiomyopathy with scarring.	Mean value of all patients with Hypertrophic cardiomyopathy without scarring.	Mean value of all patients with Non-ischemic Dilated cardiomyopathy with scarring.	Mean value of all patients with Non-ischemic Dilated cardiomyopathy without scarring.	Mean value of all control patients with scarring.	Mean value of all control patients without scarring.
Measure Participants	15	4	6	0	0	5
Mean (Standard Deviation) [Global perfusion reserve ratio]	3.19 (1.71)	5.91 (4.09)	3.16 (0.65)	3.53 (1.26)

Adverse Events

Time Frame	Adverse events were assessed during the time of the MR scan.
Arm/Group Title	Hypertrophic Cardiomyopathy - Adenosine		Hypertrophic Cardiomyopathy - Regadenoson		Non-ischemic Dilated Cardiomyopathy - Adenosine		Non-ischemic Dilated Cardiomyopathy - Regadenoson		Control - Adenosine		Control - Regadenoson
Arm/Group Description	Microvascular dysfunction (MVD) will be categorized as present based upon the presence of one of the following: Global perfusion reserve (GPR) < 2.0. Coronary sinus blood flow (CS) with velocity-encoded CMR will be measured during maximal vasodilation and at rest. GPR was calculated as the ratio of stress CS to rest CS blood flow. The presence of regional perfusion abnormalities on visual assessment of first pass perfusion images. The prevalence will be calculated by dividing the number of hypertrophic cardiomyopathy patients with MVD by the total number of patients with hypertrophic cardiomyopathy.		Microvascular dysfunction (MVD) will be categorized as present based upon the presence of one of the following: Global perfusion reserve (GPR) < 2.0. Coronary sinus blood flow (CS) with velocity-encoded CMR will be measured during maximal vasodilation and at rest. GPR was calculated as the ratio of stress CS to rest CS blood flow. The presence of regional perfusion abnormalities on visual assessment of first pass perfusion images. The prevalence will be calculated by dividing the number of hypertrophic cardiomyopathy patients with MVD by the total number of patients with hypertrophic cardiomyopathy.		Microvascular dysfunction (MVD) will be categorized as present based upon the presence of one of the following: Global perfusion reserve (GPR) < 2.0. Coronary sinus blood flow (CS) with velocity-encoded CMR will be measured during maximal vasodilation and at rest. GPR was calculated as the ratio of stress CS to rest CS blood flow. The presence of regional perfusion abnormalities on visual assessment of first pass perfusion images. The prevalence will be calculated by dividing the number of non-ischemic dilated cardiomyopathy patients with MVD by the total number of patients with non-ischemic dilated cardiomyopathy.		Microvascular dysfunction (MVD) will be categorized as present based upon the presence of one of the following: Global perfusion reserve (GPR) < 2.0. Coronary sinus blood flow (CS) with velocity-encoded CMR will be measured during maximal vasodilation and at rest. GPR was calculated as the ratio of stress CS to rest CS blood flow. The presence of regional perfusion abnormalities on visual assessment of first pass perfusion images. The prevalence will be calculated by dividing the number of hypertrophic cardiomyopathy patients with MVD by the total number of patients with hypertrophic cardiomyopathy.		Microvascular dysfunction (MVD) will be categorized as present based upon the presence of one of the following: Global perfusion reserve (GPR) < 2.0. Coronary sinus blood flow (CS) with velocity-encoded CMR will be measured during maximal vasodilation and at rest. GPR was calculated as the ratio of stress CS to rest CS blood flow. The presence of regional perfusion abnormalities on visual assessment of first pass perfusion images. The prevalence will be calculated by dividing the number of control patients with MVD by the total number of control patients.		Microvascular dysfunction (MVD) will be categorized as present based upon the presence of one of the following: Global perfusion reserve (GPR) < 2.0. Coronary sinus blood flow (CS) with velocity-encoded CMR will be measured during maximal vasodilation and at rest. GPR was calculated as the ratio of stress CS to rest CS blood flow. The presence of regional perfusion abnormalities on visual assessment of first pass perfusion images. The prevalence will be calculated by dividing the number of hypertrophic cardiomyopathy patients with MVD by the total number of patients with hypertrophic cardiomyopathy.
All Cause Mortality
	Hypertrophic Cardiomyopathy - Adenosine		Hypertrophic Cardiomyopathy - Regadenoson		Non-ischemic Dilated Cardiomyopathy - Adenosine		Non-ischemic Dilated Cardiomyopathy - Regadenoson		Control - Adenosine		Control - Regadenoson
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/10 (0%)		0/9 (0%)		0/2 (0%)		0/4 (0%)		0/3 (0%)		0/3 (0%)
Serious Adverse Events
	Hypertrophic Cardiomyopathy - Adenosine		Hypertrophic Cardiomyopathy - Regadenoson		Non-ischemic Dilated Cardiomyopathy - Adenosine		Non-ischemic Dilated Cardiomyopathy - Regadenoson		Control - Adenosine		Control - Regadenoson
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/10 (0%)		0/9 (0%)		0/2 (0%)		0/4 (0%)		0/3 (0%)		0/3 (0%)
Other (Not Including Serious) Adverse Events
	Hypertrophic Cardiomyopathy - Adenosine		Hypertrophic Cardiomyopathy - Regadenoson		Non-ischemic Dilated Cardiomyopathy - Adenosine		Non-ischemic Dilated Cardiomyopathy - Regadenoson		Control - Adenosine		Control - Regadenoson
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/10 (0%)		0/9 (0%)		0/2 (0%)		0/4 (0%)		0/3 (0%)		0/3 (0%)

Limitations/Caveats

Slow recruitment led to the end of the study.

More Information

Certain Agreements

Principal Investigators are NOT employed by the organization sponsoring the study.

There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.