Identifying Strategies to Alleviate Cardiovascular Stress in Coronary Patients During Heatwaves

Identifying Optimal Cooling Strategies for Coronary Artery Disease Patients During Heatwaves

The purpose of this study is to determine the optimal cooling strategies to alleviate cardiovascular strain of coronary artery disease individuals during a simulated North American and Australian heatwave.

Study Overview

• Status: Completed
• Conditions: Coronary Artery Disease
• Intervention / Treatment: Other: No intervention; Other: Fan; Other: Skin Wetting; Other: Fan + Skin wetting

Detailed Description

Globally, heatwaves are occurring more frequently, are of greater intensity and longer in duration. The devastating health impacts of extreme heat are increasingly recognized, particularly in vulnerable populations, such as adults with coronary artery disease (CAD). While the most effective cooling strategy during a heatwave is the use of air conditioning (AC), economical concerns can limit AC use among vulnerable populations. In addition, widespread AC use places a significant burden on the electrical grid, causing brown-outs and black-outs during periods of extreme heat.

Electric fans offer a cooling strategy with a 50-fold lower power requirement and cost compared to AC. However, the efficacy of fan use during heat waves remains contentious. The primary objective of this study is to identify the optimal cooling strategy to alleviate cardiovascular strain of CAD patients exposed to typical North American heatwave conditions (38°C with 60% relative humidity). The secondary objective is to identify the optimal cooling strategy to alleviate cardiovascular strain of CAD patients exposed to typical Australian heatwave conditions (46°C with 10% relative humidity).

• Study Type: Interventional
• Enrollment (Actual): 27
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Quebec
    • Montréal, Quebec, Canada, H1T1N6
      • Cardiovascular Prevention and Rehabilitation Centre of the Montreal Heart Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 50 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• 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 stable angina and/or perfusion defect during exercise testing.
• No CAD-related hospitalisations or changes in cardiac medications or change in pattern of angina for at least 3 months prior to enrolment

Exclusion Criteria:

• Body mass index ≥35 kg/m2.
• Currently undertaking estrogen therapy.
• Evidence of current fluid and electrolyte disorders, anemia, abnormal thyroid function, arrhythmias, diabetes, renal disease, liver disease, cerebrovascular disease, significant pulmonary disease, endocrine abnormalities, significant cognitive impairment, psychiatric disorder, substance abuse, degenerative neurological condition or any other medical condition deemed to pose risk during the proposed experiments.
• Uncontrolled hypertension (>180/110 mmHg).
• Recent (<3 months) coronary bypass surgery.
• Ejection fraction <40% and/or clinical evidence/history of heart failure.
• Significant valvular heart disease
• Resting ECG abnormalities interfering with observation of ST segment changes during testing.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

6

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 38°C and 60% RH + No intervention; The participant will enter an environmental chamber maintained at 38°C and 60% relative humidity. The participant will remain within the environmental chamber and will rest in a seated position for 3 hours.	Other: No intervention; The participant will rest in a seated position.
Experimental: 38°C and 60% RH + Fan; The participant will enter an environmental chamber maintained at 38°C and 60% relative humidity. The participant will remain within the environmental chamber and will rest in a seated position for 3 hours.	Other: Fan; A fan placed in front of the participant will provide an airflow of 4 m/s throughout the exposure.
Experimental: 38°C and 60% RH + Skin wetting; The participant will enter an environmental chamber maintained at 38°C and 60% relative humidity. The participant will remain within the environmental chamber and will rest in a seated position for 3 hours.	Other: Skin Wetting; Tap water (~18°C) will be applied every 5 minutes to the face, neck, upper and lower arms and upper and lower legs using a spray bottle.
Experimental: 38°C and 60% RH + Fan + Skin wetting; Tthe participant will enter an environmental chamber maintained at 38°C and 60% relative humidity. The participant will remain within the environmental chamber and will rest in a seated position for 3 hours.	Other: Fan + Skin wetting; A fan placed in front of the participant will provide an airflow of 4 m/s throughout the exposure. In addition, tap water (~18°C) will be applied every 5 minutes to the face, neck, upper and lower arms and upper and lower legs using a spray bottle.
Experimental: 46°C and 10% RH + No intervention; The participant will enter an environmental chamber maintained at 46°C and 10% relative humidity.	Other: No intervention; The participant will rest in a seated position.
Experimental: 46°C and 10% RH + Skin wetting; The participant will enter an environmental chamber maintained at 46°C and 10% relative humidity. The participant will remain within the environmental chamber and will rest in a seated position for 3 hours.	Other: Skin Wetting; Tap water (~18°C) will be applied every 5 minutes to the face, neck, upper and lower arms and upper and lower legs using a spray bottle.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Rate pressure product	Rate pressure product, in beats per minute per mmHg	Change from baseline to the end of the 3 hour exposure

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body core temperature	In degrees Celcius	Change from baseline to the end of the 3 hour exposure

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Skin temperature	In degrees Celcius	Change from baseline to the end of the 3 hour exposure
Sweat loss	In kilograms	Change from baseline to the end of the 3 hour exposure
Local sweat rate	In mg per minute per cm2	Measured continously during the 3 hour exposure
Skin blood flow	In arbitrary perfusion units	Measured continously during the 3 hour exposure.

Collaborators and Investigators

• Sponsor: Montreal Heart Institute
• Collaborators: National Health and Medical Research Council, Australia

Study record dates

Study Major Dates

• Study Start (Actual): February 18, 2019
• Primary Completion (Actual): June 23, 2021
• Study Completion (Actual): June 23, 2021

Study Registration Dates

• First Submitted: January 21, 2019
• First Submitted That Met QC Criteria: February 4, 2019
• First Posted (Actual): February 6, 2019

Study Record Updates

• Last Update Posted (Actual): August 1, 2023
• Last Update Submitted That Met QC Criteria: July 31, 2023
• Last Verified: July 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Heart Diseases; Cardiovascular Diseases; Vascular Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Coronary Artery Disease; Myocardial Ischemia; Coronary Disease
• Other Study ID Numbers: ICM 2019-2425

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: All individual data will be de-identified and available to the public through publications, media articles and conference presentations

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No