Characterization of Myocardial Blood Flow During Heat Exposure (PET-Heat)

Characterization of the Increase and Distribution of Myocardial Blood Flow During Heat Exposure

The purpose of this study is to determine the increase in myocardial blood flow during heat exposure and how this response is affected by age and coronary artery disease.

Study Overview

• Status: Completed
• Conditions: Coronary Artery Disease; Healthy; Aging; Hot Weather; Adverse Effect
• Intervention / Treatment: Other: Heat exposure

Detailed Description

As a result of climate change, heat waves are more frequent and of longer duration. These heat waves are associated with a higher risk of hospitalization and mortality in vulnerable populations such as people with cardiovascular disease or cardiovascular risk factors. It has been hypothesized that this observation may be explained by the cardiovascular demands imposed by heat exposure.

Heat exposure requires increased cardiac work that may place individuals with cardiovascular disease at risk of ischemic events if the metabolic demand is not compensated by adequate blood supply. However, the extent to which cardiac work increases during heat exposure remains unknown. The aim of this study is to test the hypothesis that heat exposure increases myocardial blood flow and that this increase is affected by age and coronary artery disease.

• Study Type: Interventional
• Enrollment (Actual): 80
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Quebec
    • Montréal, Quebec, Canada, H1T1C8
      • Montreal Heart Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria for Healthy Participants:

• Age between 18-40 years or 60-80 years
• Non-smoker (≥1 year)
• Non-diabetic
• Normal kidney function
• Body Mass Index <30 kg/m2
• Resting blood pressure <140/<90 mmHg
• Resting heart rate <100 bpm

Inclusion Criteria for Participants with Coronary Artery Disease:

• Age between 60-80 years old
• History of angiographic coronary disease (≥70% arterial diameter narrowing of at least one major epicardial coronary artery) and/or prior coronary revascularization and/or documented prior acute coronary syndrome and/or perfusion defect during stress testing
• Stable medications (≥4 weeks) prior to enrollment

Exclusion Criteria for Healthy Participants:

• Diagnosis of heart, vascular, respiratory, neurological or metabolic disease and/or a prescription of medication for the treatment of these diseases
• Pregnancy or lactation
• Dyslipidemia not controlled by medication

Exclusion Criteria for Participants with Coronary Artery Disease:

• Recent hospitalization (<3 months) related to coronary artery disease
• Unstable angina (<3 months)
• Recent coronary artery bypass surgery (<3 months)
• Left branch block
• Ejection fraction <40% and/or clinical signs of heart failure
• Severe valvular heart disease
• Hypertension not controlled by medication
• Diabetes not controlled by medication and/or serious complications related to diabetes

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Passive heat exposure	Other: Heat exposure; Participants will be exposed to heat exposure via a water-perfused suit to increase internal body temperature by 1.5 degrees Celsius.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Global myocardial blood flow	Measured by PET imaging with 82rubidium	Change from baseline to an increase in internal body temperature of 1.5 degrees Celsius, estimated average = 90 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Myocardial blood flow distribution	Measured by PET imaging with 82rubidium	Change from baseline to an increase in internal body temperature of 1.5 degrees Celsius, estimated average = 90 minutes
Heart rate	Measured by electrocardiogram	Change from baseline to an increase in internal body temperature of 1.5 degrees Celsius, estimated average = 90 minutes
Systolic and diastolic blood pressure	Measured by automated auscultation of the brachial artery	Change from baseline to an increase in internal body temperature of 1.5 degrees Celsius, estimated average = 90 minutes
Body weight	Measured with a scale	Measured before and after heat exposure, estimated average = 120 minutes

Collaborators and Investigators

• Sponsor: Montreal Heart Institute
• Investigators: Principal Investigator: Daniel Gagnon, PhD, Montreal Heart Institute

Study record dates

Study Major Dates

• Study Start (Actual): August 25, 2020
• Primary Completion (Actual): March 31, 2023
• Study Completion (Actual): March 31, 2023

Study Registration Dates

• First Submitted: August 25, 2020
• First Submitted That Met QC Criteria: September 14, 2020
• First Posted (Actual): September 16, 2020

Study Record Updates

• Last Update Posted (Actual): May 8, 2023
• Last Update Submitted That Met QC Criteria: May 5, 2023
• Last Verified: May 1, 2023

More Information

Terms related to this study

• Keywords: Heat; PET imaging; Myocardial blood flow
• Additional Relevant MeSH Terms: Myocardial Ischemia; Heart Diseases; Cardiovascular Diseases; Vascular Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Coronary Disease; Coronary Artery Disease
• Other Study ID Numbers: ICM 2020-2719

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