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Abnormal longitudinal, base-to-apex myocardial perfusion gradient by quantitative blood flow measurements in patients

M Hernandez-Pampaloni1, F Y Keng, T Kudo

  • 1Department of Molecular and Medical Pharmacology, UCLA School of Medicine, Los Angeles, CA 90095-1735, USA.

Circulation
|August 2, 2001
PubMed

Insights

Coronary risk factors, even without coronary artery disease (CAD), are linked to abnormal myocardial blood flow (MBF) gradients. This suggests early changes in the coronary circulation, potentially indicating preclinical CAD.

Area of Science:

  • Cardiology
  • Nuclear Cardiology
  • Cardiovascular Imaging

Background:

  • A longitudinal, base-to-apex myocardial perfusion gradient is known in coronary artery disease (CAD).
  • This gradient was previously attributed to diffuse coronary narrowing.
  • The study investigated if this gradient exists in individuals with coronary risk factors but no diagnosed CAD.

Purpose of the Study:

  • To determine if patients with coronary risk factors but without CAD exhibit an abnormal myocardial perfusion gradient.
  • To assess myocardial blood flow (MBF) using positron emission tomography (PET) in these patients.

Main Methods:

  • Myocardial blood flow (MBF) was measured using (13)N-ammonia and PET at rest and during dipyridamole-induced hyperemia.
  • Measurements were taken in 36 patients with coronary risk factors, 36 age-matched controls, and 28 young controls.
  • MBF was analyzed globally, per coronary territory, and in mid and mid-to-apical left ventricular (LV) sections.

Main Results:

  • No qualitative flow defects were observed at rest or during hyperemia in any group.
  • Absolute MBF values were similar across the three coronary territories in all subjects.
  • However, hyperemic MBF in the mid-to-apical LV sections was significantly lower than in the mid LV sections in the "at-risk" group (P<0.004), but not in control groups.

Conclusions:

  • An abnormal longitudinal, base-to-apex perfusion gradient exists in patients with coronary risk factors but no CAD.
  • This gradient during dipyridamole stress suggests functional or structural coronary circulation alterations.
  • These findings may indicate developing coronary atherosclerosis or preclinical CAD in individuals with risk factors.
Abstract

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