Comparison of Vascular Function in Emergency Service Professionals

Study Overview
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Brief Summary
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Emergency Service Professionals have an increased risk of death from heart attacks when compared to the general public. All the emergency professions share similar responsibilities such as emergency call-outs and shift work. Heart disease is the commonest cause of on-duty death amongst fire-fighters accounting for 45% and compared with 22% in police officers and 15% in the general population. The unique risk to fire-fighters is likely to reflect a combination of factors including extreme physical exertion, mental stress, heat and pollutant exposure. In this study the investigators will assess healthy career fire-fighters and age-matched healthy police officer control subjects following a sedentary period. The investigators will take blood samples to measure platelet activity (platelets are the particles in blood that help blood clot) and will examine how blood clots outside of the body. The investigators will then perform studies placing small needles in the arm to assess how the blood vessels respond following these duties. The investigators hypothesise that fire-fighters do not have pre-existing impairment of heart, blood or blood vessel function as a cumulative effect of their occupation, but rather these are acute and transitory effects following distinct fire-fighter duties. We therefore expect similar results in both occupational groups.

Official Title
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Comparison of Vascular Function in Emergency Service Professionals

Conditions
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Vascular Function, Atherothrombosis

Intervention / Treatment
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* Procedure: Forearm Vascular Study
* Procedure: Badimon Chamber


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Non-smoking healthy firefighters Exclusion Criteria: Current smoker History of lung or ischaemic heart disease Malignant arrhythmia Systolic blood pressure >190mmHg or <100mmHg Renal or hepatic dysfunction Previous history of blood dyscrasia Unable to tolerate the supine position Blood donation within the last 3 months Recent respiratory tract infection within the past 4 weeks Routine medication including aspirin and NSAIDs

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Firefighters<br>20 firefighters will attend for vascular assessments following a minimum of 48 hours off-duty. | Procedure: Forearm Vascular Study<br>* Forearm venous occlusion plethysmography to measure forearm blood flow during intra-arterial infusion of the vasodilators Verapamil (10-100 µg/min), bradykinin (100-1000 pmol/min), sodium nitroprusside (2-8 µg/min) and Acetylcholine (5-20 µg/min).<br>* Other names: VP;Procedure: Badimon Chamber<br>* Ex-vivo assessment of thrombus formation using the Badimon Chamber<br>|
| Police Officers<br>20 police officers will attend for vascular assessments following a minimum of 48 hours off-duty. | Procedure: Forearm Vascular Study<br>* Forearm venous occlusion plethysmography to measure forearm blood flow during intra-arterial infusion of the vasodilators Verapamil (10-100 µg/min), bradykinin (100-1000 pmol/min), sodium nitroprusside (2-8 µg/min) and Acetylcholine (5-20 µg/min).<br>* Other names: VP;Procedure: Badimon Chamber<br>* Ex-vivo assessment of thrombus formation using the Badimon Chamber<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Forearm blood flow measured by venous occlusion plethysmography in response to infused vasodilators |  | following 48 hours off duty | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ex-vivo thrombus formation using the Badimon chamber |  | following 48 hours off duty | 
| Plasma t-PA and PAI concentrations following infusion of bradykinin |  | During forearm study, following 48 hours off duty | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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firefighters, police officers, emergency service professionals, myocardial infarction, endothelial function, thrombosis