Related Experiment Video
Updated: Jun 21, 2025
Surgical Swine Model of Chronic Cardiac Ischemia Treated by Off-Pump Coronary Artery Bypass Graft Surgery
Published on: March 27, 2018
Clinical Efficacy of Permanent Internal Mammary Artery Occlusion in Chronic Coronary Syndrome: A Double-Blind,
Marius Reto Bigler1, Andrea Kieninger-Gräfitsch1, Christine Tschannen1
1Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
Insights
Permanent internal mammary artery occlusion improved exercise time and reduced angina in chronic coronary syndrome patients. This intervention shows promise for mitigating symptoms of myocardial ischemia.
Area of Science:
- Cardiology
- Interventional Cardiology
- Vascular Surgery
Background:
- Chronic coronary syndrome (CCS) involves impaired blood supply to the heart muscle.
- Myocardial ischemia and associated symptoms significantly impact patient quality of life.
- Existing treatments aim to improve coronary artery blood flow and reduce ischemic events.
Purpose of the Study:
- To evaluate the clinical efficacy of permanent internal mammary artery (IMA) device occlusion in patients with CCS.
- To assess the impact of IMA occlusion on exercise tolerance and ischemic symptoms.
- To investigate changes in collateral flow index (CFI) following IMA intervention.
Main Methods:
- A randomized, sham-controlled trial (CLIMACCS) involving 101 CCS patients.
- Patients were allocated to either IMA device occlusion (verum group) or sham intervention (placebo group).
- Primary endpoint: change in treadmill exercise time (ΔET) at 6 weeks; secondary endpoints: CFI and angina pectoris.
Main Results:
- While treadmill exercise time showed a trend towards improvement in the verum group (+23s vs +4s), the difference was not statistically significant (p=0.44).
- Collateral flow index (CFI) significantly improved in the verum group compared to placebo (+0.022 vs -0.039, p<0.0001).
- A significant reduction in angina pectoris was observed in the verum group (p=0.0242).
Conclusions:
- Permanent IMA device occlusion demonstrates a tendency to augment exercise capacity in CCS patients.
- The intervention is associated with improved collateral blood supply and reduced angina symptoms.
- IMA occlusion shows potential for mitigating symptoms and signs of myocardial ischemia in CCS.
Abstract:
The Clinical Efficacy of Permanent Internal Mammary Artery Occlusion in Chronic Coronary Syndrome (CLIMACCS) trial, a randomized, sham-controlled trial, tested the clinical efficacy of permanent internal mammary artery (IMA) device occlusion on symptoms in patients with chronic coronary syndrome (CCS), coronary artery occlusive blood supply, and myocardial ischemia. This was a prospective trial in 101 patients with CCS randomly allocated (1:1) to IMA device occlusion (verum group) or to IMA sham intervention (placebo group). The primary study end point was the change in treadmill exercise time (ET) (ΔET in seconds) at 6 weeks after trial intervention. Secondary study end points were the changes in collateral flow index (CFI) and angina pectoris during a simultaneous 1-minute proximal balloon occlusion of a coronary artery. CFI is the ratio between simultaneous mean coronary occlusive, divided by mean aortic pressure, both subtracted by central venous pressure. In the verum and placebo groups, the ET changed from 398 ± 176 seconds to 421 ± 198s in the verum group (p = 0.1745) and from 426 ± 162 seconds to 430 ± 166 seconds in the placebo group (p = 0.55); ΔET amounted to +23 ± 116s and +4 ± 120 seconds, respectively (p = 0.44). CFI change during follow-up equaled +0.022 ± 0.061 in the verum and -0.039 ± 0.072 in the placebo group (p <0.0001). Angina pectoris at follow-up during the coronary balloon occlusion for CFI measurement had decreased or disappeared in 20 of 48 patients in the verum group and in 9 of 47 patients in the placebo group (p = 0.0242). In conclusion, permanent IMA device occlusion tends to augment treadmill ET in response to increased coronary artery occlusive blood supply, which is reflected by mitigated symptoms and signs of myocardial ischemia.
