Identifying Strategies to Alleviate Cardiovascular Stress in Coronary Patients During Heatwaves

University of Montreal

Status: Completed

Conditions: Coronary Artery Disease

Treatments: Other: Skin Wetting; Other: Fan; Other: No intervention; Other: Fan + Skin wetting

Study type: Interventional

Funder types: Other

Identifiers

NCT03832504

ICM 2019-2425

Details and patient eligibility

About

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.

Full 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).

Enrollment: 27 patients

Sex: All

Ages: 50 to 80 years old

Volunteers: No Healthy Volunteers

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.

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: None (Open label)

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27 participants in 6 patient groups

38°C and 60% RH + No intervention

Experimental group

Description:

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.

Treatment:

Other: No intervention

38°C and 60% RH + Fan

Experimental group

Description:

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.

Treatment:

Other: Fan

38°C and 60% RH + Skin wetting

Experimental group

Description:

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.

Treatment:

Other: Skin Wetting

38°C and 60% RH + Fan + Skin wetting

Experimental group

Description:

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.

Treatment:

Other: Fan + Skin wetting

46°C and 10% RH + No intervention

Experimental group

Description:

The participant will enter an environmental chamber maintained at 46°C and 10% relative humidity.

Treatment:

Other: No intervention

46°C and 10% RH + Skin wetting

Experimental group

Description:

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.

Treatment:

Other: Skin Wetting