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Effect of Permanent Right Internal Mammary Artery Closure on Coronary Collateral Function and Myocardial Ischemia
Michael Stoller1, Christian Seiler2
1From the Department of Cardiology, Bern University Hospital, Switzerland.
Insights
Permanent right internal mammary artery device closure improved coronary collateral function in patients with coronary artery disease. This intervention reduced myocardial ischemia, offering a new therapeutic approach.
Area of Science:
- Cardiovascular Medicine
- Interventional Cardiology
- Coronary Artery Disease Research
Background:
- Coronary artery disease (CAD) remains a leading cause of mortality worldwide.
- Assessing coronary collateral function is crucial for managing myocardial ischemia.
- The role of internal mammary artery (IMA) interventions in collateralization is an area of ongoing research.
Purpose of the Study:
- To evaluate the impact of permanent right internal mammary artery (RIMA) device closure on coronary collateral function.
- To determine the effect of RIMA device closure on myocardial ischemia in patients with CAD.
- To investigate changes in collateral flow index and other ischemia markers post-intervention.
Main Methods:
- A prospective, open-label clinical trial involving 50 patients with coronary artery disease.
- Primary endpoint: Coronary collateral flow index (CFI) measured during coronary artery balloon occlusion before and 6 weeks after RIMA device closure.
- Secondary endpoints included fractional flow reserve (FFR), intracoronary ECG ST-segment elevation, and angina during occlusion.
Main Results:
- Coronary collateral flow index in the untreated right coronary artery (RCA) significantly increased post-intervention (0.071 to 0.132, P<0.0001).
- RCA fractional flow reserve showed a significant increase post-RIMA device closure (P=0.0029), despite deferral of revascularization.
- Intracoronary ECG ST-segment elevation during RCA occlusion decreased significantly (P=0.0015), and angina tended to reduce (P=0.06).
Conclusions:
- Permanent RIMA device closure appears to enhance extracardiac collateral supply to the myocardium.
- This augmentation of collateral flow effectively reduces myocardial ischemia in the supplied region.
- RIMA device closure presents a potential strategy for improving myocardial perfusion in CAD patients.
Background:
The objective of this study is to test the effect of permanent right internal mammary artery device closure on coronary collateral function and myocardial ischemia.
Methods And Results:
This was a prospective, open-label clinical trial in 50 patients with coronary artery disease. The primary study end point was coronary collateral flow index as obtained during a 1-minute proximal right coronary artery (RCA) and left coronary artery balloon occlusion at baseline before and at follow-up examination 6 weeks after distal right internal mammary artery device closure. Collateral flow index is the ratio between simultaneously recorded mean coronary occlusive pressure divided by mean aortic pressure, both subtracted by central venous pressure. Secondary study end points were fractional flow reserve during vessel patency, the quantitative intracoronary ECG ST-segment elevation, and angina pectoris during the same 1-minute coronary occlusion. Collateral flow index in the untreated RCA and left coronary artery changed from 0.071±0.082 at baseline to 0.132±0.117 (P<0.0001) at follow-up examination and from 0.106±0.092 to 0.081±0.079 (P=0.29), respectively. RCA fractional flow reserve increased significantly (P=0.0029) from baseline to follow-up examination, despite deferral of coronary intervention in all patients. There was a decrease in intracoronary ECG ST-elevation during RCA occlusion from baseline to follow-up examination (P=0.0015); it did not change in the left coronary artery. Angina pectoris during RCA occlusion tended to occur in fewer patients at follow-up versus baseline examination (P=0.06).
Conclusions:
Permanent right internal mammary artery device closure seems to augment extracardiac ipsilateral coronary supply to the effect of reducing ischemia in the dependent myocardial region.
Clinical Trial Registration:
URL: http://www.clinicaltrials.gov. Unique identifier: NCT02475408.
