当前位置： SCI文献检索 > JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY期刊下所有文献 > Tachycardia, contractility and volume loading alter conventional indexes of coronary flow reserve, but not the instantaneous hyperemic flow versus pressure slope index.

Tachycardia, contractility and volume loading alter conventional indexes of coronary flow reserve, but not the instantaneous hyperemic flow versus pressure slope index.

Abstract：

OBJECTIVES AND BACKGROUND:Because measurements of flow reserve are often made in the setting of fluctuating hemodynamic variables that cause alterations in basal or hyperemic coronary blood flow, traditional flow reserve indexes may be difficult to interpret. Prior work in this laboratory has suggested that the instantaneous hyperemic flow versus pressure slope index is a more hemodynamically stable alternative to measures of flow reserve. Although this index has no hemodynamic dependence on changes in aortic pressure, the extent to which it is affected by other factors that alter myocardial work is unknown. Therefore, the purpose of this investigation was to analyze the effects of tachycardia (induced by atrial pacing at 10 beats/min above the basal heart rate), dobutamine infusion (10 micrograms/kg per min) and saline solution volume loading (500 ml) on measurements of traditional coronary flow reserve, the resistance reserve ratio and the instantaneous hyperemic flow versus pressure slope index. METHODS:Twenty-nine open chest anesthetized dogs were studied in four sequential stages: baseline, tachycardia, dobutamine infusion and saline solution volume loading. Traditional coronary flow reserve was defined as the ratio of hyperemic coronary blood flow to basal coronary blood flow, the resistance reserve ratio as the ratio of basal coronary resistance to hyperemic coronary resistance and the instantaneous hyperemic flow versus pressure slope index as the slope of the instantaneous relation between diastolic hyperemic coronary blood flow and diastolic aortic pressure normalized by perfusion bed weight. Hyperemia was induced by intravenous adenosine infusion (1 mg/kg per min). Mean aortic pressure was kept nearly constant during the interventions by manipulation of an aortic clamp or a vena caval snare. RESULTS:The final study group comprised 18 open chest dogs. Coronary flow reserve was significantly decreased by tachycardia (3.7 +/- 1.2 to 3.0 +/- 1.2, p < 0.0001), decreased by saline solution volume loading (3.2 +/- 1.3 vs. 2.7 +/- 0.8, p = 0.06) and significantly increased by dobutamine infusion (3.2 +/- 1.3 to 4.3 +/- 1.5, p < 0.0005). In contrast, the instantaneous hyperemic flow versus pressure slope index was not affected by the three interventions (7.4 +/- 3.1 vs. 7.3 +/- 3.3, 7.4 +/- 3.2 vs. 7.4 +/- 3.4 and 7.5 +/- 3.1 vs. 7.3 +/- 3.4, respectively, all p = NS). The changes observed in the resistance reserve ratio were of similar or greater magnitude and significance to the changes in coronary flow reserve. CONCLUSIONS:The instantaneous hyperemic flow versus pressure slope index offers a hemodynamically stable alternative to measures of vascular reserve because it is independent of moderate changes in heart rate, contractility and volume loading that may occur commonly in clinical situations.

journal_name

J Am Coll Cardiol

journal_title

Journal of the American College of Cardiology

authors

Cleary RM,Ayon D,Moore NB,DeBoe SF,Mancini GB

doi

10.1016/0735-1097(92)90386-2

subject

Has Abstract

pub_date

1992-11-01 00:00:00

pages

1261-9

issue

eissn

0735-1097

issn

1558-3597

pii

0735-1097(92)90386-2

journal_volume

pub_type

杂志文章

在线工具

Tachycardia, contractility and volume loading alter conventional indexes of coronary flow reserve, but not the instantaneous hyperemic flow versus pressure slope index.