Author + information
- Received June 10, 1992
- Revision received September 9, 1992
- Accepted September 21, 1992
- Published online April 1, 1993.
- Krishnankutty Sudhir, MD, PhD∗,1,
- John S. MacGregor, MD, PhD,
- Sophie D. Barbant, MD2,
- Elyse Foster, MD, FACC,
- Peter J. Fitzgerald, MD, PhD3,
- Kanu Chatterjee, MB, FRCP, FACC and
- Paul G. Yock, MD, FACC
- ↵∗Address for correspondence: Krishnankutty Sudhir, MC, PhD, Box 0124, University of California at San Francisco, San Francisco, California 94145.
Objectives. The aim of this study was to determine the differential effects of nitroglycerin, ergonovine and adenosine on the resistantce vessels in vivo by using a Doppler-tipped guide wire in combination with an ultrasound imaging catheter.
Background. Catheter-based two-dimensional intravascular ultrasound yields images of the coronary arteries from which cross-sectional areas can be measured. Intravascular Doppler ultrasound techniques allow measurement of coronary blood flow velocity. The simultaneous use of the two techniques can yield anatomic and physiologic information on conductance and resistance vessels but has not been tried in the coronary arteries.
Methods. In 15 dogs, we studied coronary Bow and vascular reactivity in response to pharmacologic agents using two approaches: 1) a 30-MHz, 4.3F imaging catheter placed alongside a 0.018-in. (0.046 cm) Doppler wire in the circumflex or left anterior descending coronary artery (n = 5); 2) the ultrasound imaging catheter introduced directly over a 0.014-in. (0.036 cm) Doppler wire (n = 10). Vasodilator and vasoconstrictor responses were studied by using intracoronary nitroglycerin (50,100 and 200 μg), ergonovine (200 μg) and adenosine (6 mg).
Results. Nitroglycerin caused a dose-dependent increase in epicardial coronary artery cross-sectional area and, to a lesser extent, in average peak flow velocity, resulting in an increase in volumetric coronary blood flow of 39% and 59% at the doses of 100 and 200 μg, respectively. With these doses of nitroglycerin, the decrease in diastolic to systolic velocity ratio and the increased change in cross-sectional area from end-diastole to end-systole suggested an enhanced epicardial coronary artery compliance. With ergonovine, a 12% reduction in epicardial coronary artery cross-sectional area was seen, without a significant change in average peak velocity, resulting in a 15% decrease in volumetric coronary blood flow. Adenosine caused a 270% increase in average peak velocity but no change in epicardial coronary artery cross-sectional area, resulting in a 270% increase in volumetric bood flow.
Conclusions. This study demonstrates that nitroglycerin and ergonovine predominantly influence coronary conductance arteries whereas adenosine mainly dilates coronary resistance vessels. These findings also demonstrate that the combined use of a two-dimensional and a Doppler ultrasound transducer within one catheter assembly can provide information on the differential effects of vasoactive agents on the epicardial and microvascular coronary circulation.
↵1 Dr. Sudhir, & C. J. Martin Fellow, is funded by the National Health and Medical Research Council of Australia, Canberra, Australian Capital Territory, Australia.
↵2 Dr. Barbant is funded by the Federation de Cardiologie, Paris, France.
↵3 Dr. Fitzgerald is funded through the California Affiliate of the American Heart Association, Burlingame, California and the Hewlett-Packard Corporation. Andover, Massachusetts.
☆ All editorial decisions for this article, including selection of referees, were made by a Guest Editor. This policy applies to all articles with authors from the University of California San Francisco.
- Received June 10, 1992.
- Revision received September 9, 1992.
- Accepted September 21, 1992.