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Importance of non-stenosed donor coronary arteries for collateral flow reserve
1Second Department of Internal Medicine, Toyama Medical and Pharmaceutical University, Japan.
Insights
Significant stenoses in donor coronary arteries impair collateral flow reserve. In patients with non-stenosed donor arteries, collateral circulation increases with demand, but this augmentation is compromised by stenoses.
Area of Science:
- Cardiovascular Medicine
- Interventional Cardiology
- Physiology
Background:
- Coronary artery disease (CAD) can lead to compromised blood flow.
- Collateral circulation plays a vital role in supplying blood to ischemic areas.
- The impact of donor artery stenosis on collateral flow reserve is not fully understood.
Purpose of the Study:
- To investigate if significant stenoses in donor coronary arteries affect collateral flow reserve.
- To determine how collateral circulation responds to increased myocardial oxygen demand in the presence of donor artery stenosis.
Main Methods:
- Coronary arteriography was performed in 22 patients with stable effort angina and complete coronary artery obstruction.
- Patients were divided into two groups: without (Group I) and with (Group II) significant stenoses in donor arteries.
- Collateral circulation was assessed using contrast appearance time (CAT) before and during rapid atrial pacing.
Main Results:
- Rapid atrial pacing reduced CAT in Group I (non-stenosed donors), indicating augmented collateral flow.
- CAT did not significantly change in Group II (stenosed donors) during rapid atrial pacing.
- Pressure gradients across collateral circulation remained stable in both groups.
Conclusions:
- Coronary collateral circulation can be augmented in response to increased myocardial oxygen demand when donor arteries are not stenosed.
- Significant stenoses in donor coronary arteries compromise the ability to increase collateral blood flow.
- Donor artery stenosis limits the functional capacity of collateral circulation in CAD patients.
Abstract:
To elucidate whether the presence of significant stenoses in donor coronary arteries compromises collateral flow reserve, coronary arteriography was performed in 22 patients with stable effort angina who had a complete obstruction in one of the major coronary arteries. The patients were divided into two groups according to the absence (group I: n = 11) or presence (group II: n = 11) of significant stenoses (> or = 75% stenosis of the luminal diameter) in donor arteries. After conventional cardiac catheterization, coronary arteriography was repeated before and during rapid atrial pacing. Coronary collateral circulation was evaluated by means of angiographic contrast appearance time (CAT) which was defined as the time (s) until the epicardial segments distal to the site of complete occlusion were opacified after the injection of contrast medium into the donor artery. The pressure gradient across the collateral circulation (mean aortic pressure minus left ventricular end-diastolic pressure) remained unchanged before and during rapid atrial pacing (group I: 95 +/- 14 vs. 99 +/- 15 mmHg; group II: 91 +/- 18 vs. 94 +/- 16 mmHg). Rapid atrial pacing decreased the contrast appearance time in group I from 1.73 +/- 0.34 to 1.47 +/- 0.37 s (P < 0.01), but was not changed in group II from 1.68 +/- 0.36 to 1.73 +/- 0.51 s (P = n.s.). It was concluded that coronary collateral circulation is further augmented in response to an increase in myocardial oxygen demand in patients with non-stenosed donor coronary arteries and significant stenoses in donor arteries compromise an increase in collateral blood flow.