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Coronary Steal Via Natural Internal Mammary Artery-To-Coronary Artery Bypasses (CIMA)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT02332564
Recruitment Status : Recruiting
First Posted : January 7, 2015
Last Update Posted : October 17, 2019
Information provided by (Responsible Party):
University Hospital Inselspital, Berne

Brief Summary:

CORONARY ARTERY DISEASE AND THE BENEFIT OF BYPASSES Despite considerable advances in medicine, cardiovascular diseases remain the number one cause of death globally. In industrialized countries, coronary artery disease (CAD) is the leading cause of death, consequence of myocardial infarction (MI). Artificial - or natural - bypasses exert a protective effect by providing an alternative source of blood flow to a myocardial territory potentially affected by an acute coronary occlusion. Coronary collaterals represent pre-existing inter-arterial anastomoses and as such are the natural counter-part of surgically created bypasses. In patients with chronic CAD, sufficient coronary collaterals have been shown to confer a significant benefits in terms of overall mortality and cardiovascular events.

EXTRACARDIAC-TO-CORONARY COLLATERAL SUPPLY Commonly, coronary collaterals are implicitly understood to exist between coronary artery branches. However, the structural existence of coronary collaterals with an extracardiac connection has been confirmed by anatomical investigations. Pathophysiologically and with regard to a potential for arteriogenic stimulation, the connections from the internal mammary arteries, are of special interest.

In a recently published work the investigators have investigated the effect of temporary balloon occlusion of the distal IMA on coronary collateral function. There were equivocal findings for the left circumflex coronary artery: CFI was increased by ipsilateral IMA occlusion, but the level of myocardial ischemia was unchanged.

MYOCARDIAL STEAL VIA INTERNAL MAMMARY ARTERIES In the investigators' previous study, the coronary occlusion with simultaneous distal IMA occlusion was always performed first as a conservative measure against false-positive detection of internal-mammary-to-coronary artery connections. Repetitive coronary occlusions per se result in higher collateral flow by collateral recruitment and reduced ischemia by ischemic preconditioning and augmented collateral function. Conversely, the sensitivity of the employed method was reduced and might have contributed to the equivocal findings in case of the left circumflex artery. Moreover, the hypothesize d mechanism of localized pressure augmentation was not investigated.

This study aims to further characterize the prevalence and function of natural ipsilateral IMA-to-coronary connections, as well as to investigate the hemodynamic mechanisms of coronary collateral function augmentation by distal IMA occlusion. In the investigators' last study, the increased coronary collateral function in response to manipulation of a potential coronary collateral donor (in this case, the IMA) was taken as indirect evidence for the existence of IMA-to-coronary-artery connections. Thus, the employed distal IMA occlusion served as a positive stimulus. Conceptually, additional evaluation with a negative stimulus could heighten the discriminatory power of the investigation. This could be in the form of a hyperemic stimulus affecting the collateral donor, ie in analogy to myocardial or coronary steal (ie, a reduction in coronary collateral supply to a collateral recipient).

Condition or disease Intervention/treatment
Coronary Artery Disease Ischemia Other: Coronary Artery Balloon Occlusion for Determination of Collateral Flow Index

  Show Detailed Description

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Study Type : Observational
Estimated Enrollment : 100 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Coronary Steal Via Natural Internal Mammary Artery-To-Coronary Artery Bypasses
Study Start Date : December 2014
Estimated Primary Completion Date : April 2020
Estimated Study Completion Date : December 2020

Resource links provided by the National Library of Medicine

Group/Cohort Intervention/treatment
Coronary Artery Disease
Patient with significant coronary artery disease
Other: Coronary Artery Balloon Occlusion for Determination of Collateral Flow Index
Coronary Artery Balloon Occlusion for Determination of Collateral Flow Index

no Coronary Artery Disease
Patient without significant coronary artery disease
Other: Coronary Artery Balloon Occlusion for Determination of Collateral Flow Index
Coronary Artery Balloon Occlusion for Determination of Collateral Flow Index

Primary Outcome Measures :
  1. Coronary collateral function (CFI) [ Time Frame: Baseline ]
    Coronary collateral function (CFI)

Secondary Outcome Measures :
  1. Myocardial ischemia during temporary coronary balloon occlusion [ Time Frame: Baseline ]
  2. Proximal IMA pressure immediately before and during (ipsilateral) reactive arm hyperemia. [ Time Frame: Baseline ]
  3. Distal IMA CFI [ Time Frame: Baseline ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Probability Sample
Study Population
Patients electively referred for coronary angiography

Inclusion Criteria:

  • Age > 18 years
  • Referred for elective coronary angiography
  • Written informed consent to participate in the study

Exclusion Criteria:

  • Acute coronary syndrome; unstable cardiopulmonary conditions
  • Severe cardiac valve disease
  • Congestive heart failure NYHA III-IV
  • Prior coronary artery bypass surgery / prior cardiac surgery
  • Coronary artery disease unsuitable for intracoronary pressure measurements
  • Prior Q-wave myocardial infarction in the vascular territory undergoing collateral function determination
  • Severe renal or hepatic failure
  • Pregnancy

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT02332564

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Bern University Hospital Recruiting
Bern, Switzerland, 3010
Contact: Marius Bigler, MD    +41 31 632 ext 8030   
Contact: Christian Seiler, MD, Prof.    +41 31 632 ext 2111   
Principal Investigator: Christian Seiler, MD, Prof.         
Sponsors and Collaborators
University Hospital Inselspital, Berne
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Principal Investigator: Christian Seiler, MD, Prof. Department of Cardiology, Bern University Hospital

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Responsible Party: University Hospital Inselspital, Berne Identifier: NCT02332564     History of Changes
Other Study ID Numbers: SNCTP000001138
2631 ( Other Identifier: Bern University Hospital )
First Posted: January 7, 2015    Key Record Dates
Last Update Posted: October 17, 2019
Last Verified: October 2019
Keywords provided by University Hospital Inselspital, Berne:
Circulation, Collateral
Coronary Artery Disease
Internal Mammary-Coronary Artery Anastomosis
Additional relevant MeSH terms:
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Coronary Artery Disease
Myocardial Ischemia
Coronary Disease
Heart Diseases
Cardiovascular Diseases
Arterial Occlusive Diseases
Vascular Diseases
Pathologic Processes