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Hydra, a Computer-Based Platform for Aiding Clinicians in Cardiovascular Analysis and Diagnosis
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J curve in antihypertensive therapy--does it exist? A personal point of view

J M Cruickshank

    Cardiovascular Drugs and Therapy
    |October 1, 1994
    PubMed

    Insights

    Coronary autoregulation maintains blood flow despite blood pressure changes. However, reduced coronary flow reserve in conditions like left ventricular hypertrophy and coronary artery disease makes patients vulnerable to drops in diastolic blood pressure.

    Area of Science:

    • Cardiology
    • Physiology

    Background:

    • Coronary blood flow is regulated by autoregulation to maintain consistent perfusion despite changes in perfusion pressure, primarily diastolic blood pressure (DBP).
    • A healthy coronary artery system possesses a coronary flow reserve (CFR) of approximately 5, indicating a fivefold dilation capacity.
    • Left ventricular hypertrophy (LVH) and coronary artery disease (CAD) significantly impair this reserve, reducing the ability of coronary arteries to dilate.

    Purpose of the Study:

    • To investigate the impact of reduced diastolic blood pressure (DBP) on coronary blood flow and left ventricular function in patients with compromised coronary flow reserve.
    • To highlight the clinical implications of DBP management in high-risk cardiovascular patients.

    Main Methods:

    • The study focuses on the physiological response of coronary circulation to changes in perfusion pressure (DBP).
    • It examines the consequences of reduced DBP in the context of impaired coronary flow reserve, specifically in the presence of left ventricular hypertrophy and/or coronary artery disease.
    • The relationship between DBP and mortality in coronary artery disease patients is analyzed, referencing a J-curve pattern.

    Main Results:

    • In patients with LVH and/or CAD, a decrease in DBP, which is typically well-tolerated, leads to a significant reduction in coronary blood flow.
    • This reduction in coronary flow precipitates adverse events, including electrocardiogram (ECG) changes and left ventricular dysfunction.
    • A J-curve relationship exists between DBP and coronary artery disease-related death in these high-risk individuals.

    Conclusions:

    • Lowering DBP in patients with LVH and/or CAD, particularly to levels below the mid-80s mmHg, is associated with increased risk and is considered imprudent.
    • Maintaining adequate DBP is crucial for preserving coronary perfusion and left ventricular function in patients with compromised coronary flow reserve.

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