Prognostic Value of Hyperpolarized 13C MRI for Clinical Myocardial Viability

Heart failure due to coronary artery disease represents a significant cause of mortality. The detection of patients eligible for bypass surgery is a pivotal concern. Nevertheless, the optimal approach for patient selection based on conventional imaging scans remains unclear. The proposed method (Hyperpolarized 13C MRI) has gained extensive use in evaluating in vivo metabolism. This method avoids ionizing radiation and provides critical insights into cardiac function. The feasibility study aims to investigate this method for patient selection before bypass surgery. This innovative imaging technique facilitates the identification of two simple molecules, bicarbonate and lactic acid, produced at high rates by normal heart metabolism. Both bicarbonate and lactate originate from the same precursor molecule, pyruvate. The data generated from this study holds the potential to refine diagnostic precision.

Study Overview

• Status: Recruiting
• Conditions: Coronary Artery Disease; Myocardial Viability; Ischemic Heart Disease (IHD)

Detailed Description

PRIMARY OBJECTIVES:

The principal aim of this investigation is to employ noninvasive techniques for the in vivo assessment of segmental myocardial metabolism. This will be achieved by measuring the hyperpolarized (HP) 13C bicarbonate-to-lactate (bic/lac) ratio in patients scheduled for coronary artery bypass surgery (CABG), both preoperatively and 4-6 months postoperatively. These findings will be compared with a control group of healthy subjects to establish normal metabolic values.

SECONDARY OBJECTIVES:

In addition to the primary objectives, this study seeks to accomplish the following secondary objectives:

1. To ascertain the safety profile and tolerability of HP [1-13C] pyruvate administration during the MRI exam.
2. To evaluate the reproducibility of the HP 13C MRI data if the optional second injection of hyperpolarized 13C pyruvate is administered.

EXPLORATORY OBJECTIVES:

In pursuit of further insights, this research also aims to explore the following:

1. Investigate potential associations between blood measurements for pyruvate, triglycerides, free fatty acids, and insulin levels with the bicarbonate/lactate ratio within the myocardium.
2. Explore correlations between segmental myocardial metabolism (the bic/lac ratio) and mechanical function, such as echocardiographic measurements of wall motion.

• Study Type: Observational
• Enrollment (Estimated): 30

Contacts and Locations

• Study Contact: Name: Sarah S McNeil; Phone Number: 214-645-7700; Email: sarah.mcneil@utsouthwestern.edu

Study Locations

• United States
  • Texas
    • Dallas, Texas, United States, 75390
      • Recruiting
      • University of Texas Southwestern Medical Center
      • Contact: Sarah S McNeil, RN; Phone Number: 214-645-7700; Email: sarah.mcneil@utsouthwestern.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Potential human subjects will be identified and referred by cardiothoracic surgeons (Drs. Peltz or Jessen.) and their clinical team will discuss the opportunity to participate with their patients or potential subjects. A research nurse from the Cardiovascular and Thoracic Surgery Clinical Trials office will directly contact the subject to further discuss study participation, otherwise, the details and contact information of clinical study coordinator will be provided for prescreening. Once the study candidate expresses interest, details will be forwarded to the Advanced Imaging Research Center and an appointment will be scheduled for the 13C metabolic imaging exam. All NIH and UTSWMC regulations related to confidentiality, recruitment practices, etc., will apply. All patients will be reviewed for medical history, demographics, subject eligibility criteria, MRI screening form, informed consent, and pregnancy test for females of child-bearing potential.

Description

The eligibility criteria for this feasibility study are designed to select participants who will provide valuable insights into myocardial metabolism using HP-13C MRI in various contexts related to ischemic heart failure. These criteria aim to ensure that the study population is diverse and representative of the patient groups under investigation.

Inclusion/Exclusion Criteria:

• Age range: 20 to 80 years
• Sex: Random allocation
• Left ventricular ejection fraction (LVEF):
• Preoperative patients with LVEF < 0.35
• Healthy subjects with LVEF > 0.50
• Clinical history:
• Previous myocardial infarction (MI): Excluded for healthy subjects, included for preoperative patients.
• Diabetes mellitus: Excluded for all participants.
• Hypertension: Included for all participants
• Mean blood pressure: Systolic < 140 mm Hg and Diastolic < 90 mm Hg for all participants
• Mean heart rate: 78 beats/min for all participants
• Current smoker status: Included but will be reported.
• Medication use within 24 hours: Use will be reported.
• Coronary artery bypass surgery history: Excluded for healthy subjects, included for preoperative patients.
• Infarct type and location: Excluded for healthy subjects, included for preoperative patients with various Q-wave infarct types and locations.
• Number of diseased coronary vessels: Excluded for healthy subjects, included for preoperative patients with at least one diseased vessel.
• Additional medical history and clinical data: Variations in data availability are expected based on the practices of referring physicians and will be documented.

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort
Healthy Control Subjects; Healthy volunteers (male or female, aged 20-80 years) who are eligible for a 3T MRI. They must have no history of coronary artery disease, diabetes, or other exclusionary medical diagnoses.
Preoperative CAD Patients; Male or female patients (aged 20-80 years) who are scheduled for Coronary Artery Bypass Surgery as standard of care. These patients have 1, 2, or more stenotic coronary vessels and are eligible for a 3T MRI.
Postoperative CAD Patients; The same population of patients from the preoperative group undergoing a follow-up evaluation 4-6 months after their surgical coronary revascularization.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Bicarbonate-to-Lactate Ratio in Healthy Control Subjects	Assessment of normal segmental myocardial metabolism by measuring the ratio of hyperpolarized (HP) [13C]-bicarbonate to HP [1-13C]lactate (bic/lac ratio). This is obtained during an HP-13C MRI utilizing [1-13C] pyruvate to establish baseline normal values for healthy subjects.	Baseline (Day 1 of imaging)
Bicarbonate-to-Lactate Ratio in Preoperative CAD Patients	Assessment of segmental myocardial metabolism and mechanical function in patients scheduled for coronary artery bypass surgery. The bic/lac ratio is measured using HP-13C MRI to identify abnormal cardiac metabolism and impaired oxidative function. These metabolic findings will be correlated with echocardiographic measurements of wall motion and viability studies obtained by the referring cardiologist.	Preoperative imaging day
Change in Bicarbonate-to-Lactate Ratio Post-Surgery	Follow-up assessment of segmental myocardial metabolism to evaluate the remodeling of cardiac metabolism as a consequence of surgery. The bic/lac ratio is measured using HP-13C MRI to determine if the ratio has increased compared to the patient's preoperative baseline, indicating improved oxidative function.	4-6 months after surgical coronary revascularization

Collaborators and Investigators

• Sponsor: University of Texas Southwestern Medical Center
• Collaborators: American Heart Association
• Investigators: Principal Investigator: Gaurav Sharma, PhD., University of Texas Southwestern Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): June 30, 2023
• Primary Completion (Estimated): June 30, 2026
• Study Completion (Estimated): June 30, 2026

Study Registration Dates

• First Submitted: August 24, 2023
• First Submitted That Met QC Criteria: September 13, 2023
• First Posted (Actual): September 21, 2023

Study Record Updates

• Last Update Posted (Actual): February 27, 2026
• Last Update Submitted That Met QC Criteria: February 24, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Mitochondrial function; Coronary Artery Bypass Surgery; Hyperpolarized 13C MRI; Segmental myocardial metabolism
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Heart Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Coronary Disease; Coronary Artery Disease; Myocardial Ischemia
• Other Study ID Numbers: STU-2020-0953; Velos# 31471 (Other Identifier: University of Texas Southwestern Medical Center)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No