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Angiographic abnormalities associated with alterations in regional myocardial blood flow in coronary artery disease
Insights
Myocardial blood flow is significantly reduced in patients with coronary artery disease (CAD) and asynergy. Both stenosis severity and asynergy impact flow, but collateral circulation
Area of Science:
- Cardiology
- Nuclear Medicine
- Radiology
Background:
- Coronary artery disease (CAD) affects myocardial blood flow.
- Asynergy, a regional wall motion abnormality, is a clinical manifestation of CAD.
- The interplay between coronary stenosis, asynergy, and myocardial perfusion is complex.
Purpose of the Study:
- To evaluate the association between myocardial blood flow (MBF) and angiographic findings.
- To compare MBF in patients with and without asynergy and coronary artery disease.
- To investigate the influence of stenosis severity and collateral circulation on MBF in CAD.
Main Methods:
- Myocardial blood flow was measured at rest using an Anger camera and computer after intracoronary injection of 133xenon.
- Patients were categorized into three groups: with asynergy, with CAD but without asynergy, and without CAD.
- Regional and whole-heart MBF were compared across groups and correlated with coronary angiographic findings.
Main Results:
- Whole-heart blood flow was significantly reduced in patients with asynergy compared to controls.
- Regional myocardial blood flow was reduced in asynergic regions (anteroapical and posterolateral).
- MBF reduction was associated with stenosis severity (<50% and <75%), with asynergy exacerbating the flow reduction. Collateral circulation's role was variable and uncertain.
Conclusions:
- Both the degree of coronary artery stenosis and the presence of asynergy are crucial in evaluating MBF alterations in CAD.
- Asynergy significantly contributes to reduced myocardial blood flow, independent of stenosis severity in some cases.
- The impact of collateral circulation on myocardial blood flow in the context of asynergy requires further investigation.
Abstract:
To evaluate the association between alterations in myocardial blood flow and angiographic findings, myocardial blood flow was compared in 26 patients with asymergy, 15 patients with a similar extent of coronary artery disease but without asynergy, and 10 patients without coronary artery disease or obvious myocardial or valvular disease. Myocardial blood flow was measured at rest with an Anger camera and PDP-11/20 computer after the intracoronary injection of 133xenon. In comparison with the normal subjects, whole heart blood flow was significantly reduced in patients with asynergy. In addition, myocardial blood flow in regions of anteroapical asynergy was reduced (85-7 +/- 7-0 ml/min per 100 g3 in controls to 65-4 +/- 4-5, P less than 0-05) and a similar reduction was noted in regions of posterolateral asymergy (91-5 +/- 8-8 in controls to 66-8 +/- 5-0, P less than 0-05). In general, regional myocardial blood flow was reduced distal to left anterior descending or left circumflex stenosis of less than 50 per cent, with a trend toward further reduction distal to less than 75 per cent stenosis. In these same patients, the presence of anteroapical or posterolateral asynergy resulted in a similar trend to even greater reduction of flow. The effect of collaterals was variable: 7 of 8 patients without asynergy but with less than 75 per cent left anterior descending stenosis and collateral circulation to the lower left anterior descending quadrant had minimally reduced flows. However, in the 17 patients with anteroapical asynergy, regional myocardial blood flow was very similar in the 9 patients with collaterals compared with the 8 patients without them. This study suggests that the degree of coronary artery stenosis and presence of asynergy are both important in evaluating alterations in myocardial blood flow in coronary artery disease, while the role of collaterals remains uncertain.