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NCT Number: NCT06617117

Central vs Brachial BP, Exercise, and Coronary Artery Disease

High blood pressure (BP) is a major risk factor for coronary artery disease (CAD), with 30-70% of CAD patients having elevated BP. The conventional method of measuring BP in the arm (brachial BP) may miss some cases, as individuals can have normal brachial pressure but elevated central systolic pressure, which is a more critical predictor of cardiovascular events. Lowering BP is a key objective in cardiac rehabilitation programs.

Examining BP responses after a single bout of exercise could help predict how effectively exercise lowers BP over time. There is a well-established reduction in BP, known as post-exercise hypotension (PEH), which occurs after exercise. This drop is typically around 8 to 9 mmHg and is observed in individuals with and without hypertension. However, it may not occur in people with CAD. The reason for this difference is unclear but may relate to individual variability in exercise responses.

No research has closely examined individual responses to PEH in people with CAD, and it remains unclear whether exercise affects central and brachial BP differently, as some medications do. Additionally, exercise intensity may influence the magnitude of the BP reduction post-exercise. Higher-intensity exercise tends to cause a more significant BP drop, both in hypertensive and non-hypertensive individuals, typically within 20 to 60 minutes post-exercise.

Therefore, the present study aimed to determine the acute effects of combined exercise at different intensities on central and brachial blood pressure in individuals with and without coronary artery disease.

The key research questions were:

1. Is the BP response of central and brachial arteries to acute combined exercise similar? How does coronary artery disease influence these BP responses? Is there individual variability among people with CAD? 2. Does high-intensity exercise, compared to moderate-intensity exercise, produce more pronounced changes in BP in the post-acute exercise period?

All participants were asked to:

Complete two combined exercise sessions - one moderate- and one high-intensity bout. The order of the sessions was randomly assigned, similar to flipping a coin.

BP was measured before and after each acute exercise bout in the laboratory. The researchers compared central and brachial BP responses between exercise intensities (high vs. moderate) and populations (individuals with and without CAD).

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Key information

Conditions

Coronary Arterial Disease (CAD) Arterial Occlusive Diseases Arteriosclerosis Cardiovascular Diseases Coronary Artery Disease Coronary Disease Heart Diseases Myocardial Ischemia Vascular Diseases

Age range

55 year–85 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Faculdade de Motricidade Humana - University of Lisbon

Lisbon, Lisbon District, 1495-688, Portugal

About this study

This study was designed as a randomized cross-over, repeated measures experiment. All participants underwent two combined exercise sessions of varying intensities, specifically high (HIGH) and moderate (MOD), in a randomized sequence (http://www.randomizer.org/). Before the exercise sessions, all participants underwent both cardiopulmonary exercise testing and 1RM testing, followed by a DEXA scan during a subsequent visit to the laboratory. Each participant completed all experimental sessions consistently at the same time of the day, specifically in the mornings, with at least 48h between sessions to reduce diurnal variation. Post-exercise measurements were conducted at 5, 15 and 30 min after exercise. Participants reported to the laboratory in a fasted state (≥ 4h), and refrained from vigorous exercise, vitamin supplements, and foods/beverages containing caffeine and alcohol for at least 12 h preceding each experimental session.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

for the coronary artery disease group:

  • Middle-aged and older adults with stable coronary artery disease (over 55 years old)

Inclusion criteria

for the control group:

  • Aged-matched healthy adults free of cardiovascular, respiratory, or metabolic disease and with no more than 2 traditional risk factors.
  • Physically active defined as engaging in exercise at least 3 times per week over the past 6 months

Exclusion criteria

for both groups:

  • Cognitive impairment
  • Pulmonary disease
  • Uncontrolled atrial or ventricular dysrhythmia
  • Disability or mental illness
  • Extra-cardiac disease

Treatment and study plan

High-intensity combined exercise

Other

The main part consisted of interval cycling exercise, comprising 5x2 min at the second ventilatory threshold interspersed with 4x2 min at the first ventilatory threshold, followed by 2-min unloading pedalling. Subsequently, participants completed resistance exercises (2 sets of 12 repetitions), targeting the same muscle groups of the moderate-intensity exercise, at an intensity of 80% of their 1 repetition maximum.

Moderate-intensity combined exercise

Other

The main part of the exercise session consisted of an 18-min cycling continuous aerobic exercise at the first ventilatory threshold, followed by 2-min of unloading cycling. Subsequently, participants engaged in resistance exercises - 2 sets of 12 repetitions at 60% of their one repetition maximum. These resistance exercises were part of a machine-assisted circuit training program, encompassing Chest Press, Leg Curl, Low Row, Leg Press, Lat Pull-down, and Leg Extension.

Primary outcomes

  1. Central blood pressure

    Time frame: Baseline, before acute combined exercise/applanation tonometry; 5, 15 and 30 minutes after acute combined exercise

    Central systolic blood pressure (cSBP) was measured using non-invasive carotid tonometry (Complior, ALAM Medical) with participants in a supine position. Carotid waveforms were calibrated from brachial diastolic BP (bDBP) and mean arterial pressure (2/3 bDBP + 1/3 bSBP), assumed constant throughout the vascular system. A single operator performed 2 repeated measurements on the right side, each with 10 waveforms of higher than 90% quality, and the average was used. The pressure from wave reflection on SBP was derived as the difference between bSBP and cSBP.

  2. Brachial blood pressure

    Time frame: Baseline, before acute combined exercise/applanation tonometry; 5, 15 and 30 minutes after acute combined exercise

    Brachial Blood pressure was measured in the supine position using an Omron sphygmomanometer after a 10-min rest. Hypertension was defined per ESH guidelines (bSBP ≥140 mmHg and/or bDBP ≥90 mmHg).

Secondary outcomes

  1. Carotid femoral pulse wave velocity (cfPWV)

    Time frame: Baseline, before acute combined exercise/applanation tonometry; 5, 15 and 30 minutes after acute combined exercise

    Central arterial stiffness was measured via carotid-femoral pulse wave velocity (cf PWV), wherein both carotid and femoral waveforms were collected simultaneously using piezoelectric pressure mechanotransducers (Complior, ALAM Medical, Paris, France). Pulse transit times (PTT) were automatically calculated using the intersect tangent algorithm of the foot-to-foot method, enabling the calculation of cfPWV as the ratio of distance to PTT. Travel time distances were defined as the taped measured distance over body surfaces between the two recording sites of interest, with the cf distance corrected by a factor of 0.8.

Sponsors and collaborators

Lead sponsor

Egas Moniz - Cooperativa de Ensino Superior, CRL

Other

Registry information

Official study title

Dynamic Acute Responses of Different Intensity-dependent Exercises on the Autonomic and Vascular Systems in People With Coronary Artery Disease

Important dates

Study start
2018
Primary completion
2020
Study completion
2020
First posted
Sep 27, 2024
Registry last updated
Sep 27, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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