Experimental study
Physiologic basis for assessing critical coronary stenosis: Instantaneous flow response and regional distribution during coronary hyperemia as measures of coronary flow reserve

https://doi.org/10.1016/0002-9149(74)90743-7Get rights and content

Abstract

Quantitative hemodynamic assessment of coronary stenosis has not been previously reported. Resting coronary blood flow and its regional distribution are insensitive indexes for determining critical stenosis, but flow response to a hyperemic stimulus quantifies restrictions on maximal flow due to coronary arterial lesions. Coronary flow responses to temporary occlusion and to selective main coronary arterial injection of sodium diatrizoate (Hypaque-M 75 percent) were studied in 12 consecutive dogs with a surgically implanted electromagnetic flowmeter and separate micrometer constrictor on the left circumflex coronary artery. Selective Hypaque injection adequate for coronary cineangiography increased coronary flow to four times the resting base-line value, peaking at 6 seconds and lasting 3 minutes, a response equivalent to hyperemia after 10 seconds of circumflex arterial occlusion. With progressive micrometer constriction, resting flow measurements did not decrease until there was 85 percent stenosis. Hyperemia after intracoronary injection of Hypaque decreased when there was 30 to 45 percent stenosis and disappeared when there was 88 to 93 percent stenosis. Myocardial images obtained by gamma camera after left atrial injection of 131iodine-macroaggregated albumin demonstrated uniform regional distribution of resting flow in spite of severe constriction. However, 6 seconds after selective Hypaque injection, left atrial injection of 99mtechnetium macroaggregates demonstrated distinct perfusion abnormalities in the region of circumflex stenosis. Thus, flow distribution with a severe lesion was normal at rest but showed marked differences due to restricted circumflex versus normal anterior descending hyperemic response after injection of Hypaque. Flow response and regional distribution during coronary hyperemia caused by Hypaque are quantitative measures for physiologically assessing critical coronary stenosis and flow reserve with potential applicability to patients.

References (25)

  • RA Olsson et al.

    Myocardial reactive hyperemia in the unanesthetized dog

    Am J Physiol

    (1965)
  • EC Elliot et al.

    Day-to-day changes in coronary hemodynamics secondary to constriction of circumflex branch of left coronary artery in conscious dogs

    Circ Res

    (1968)
  • Cited by (1174)

    • Noninvasive Coronary Physiological Assessment Derived From Computed Tomography

      2024, Journal of the Society for Cardiovascular Angiography and Interventions
    • Dogmas and heresies in coronary blood flow regulation

      2024, International Journal of Cardiology
    View all citing articles on Scopus
    View full text