Comparison of Bidirectional Palpation Test and Transit Time Flow Measurement for LIMA-LAD Graft Patency
Conditions: Coronary Arterial Disease (CAD), Coronary Artery Bypass, LIMA, Graft Patency, LAD (Left Anterior Descending) Coronary Artery Stenosis, Saphenous Vein Graft Patency, LIMA-LAD ANASTOMOSIS, LIMA GREFT PATENCY
Sponsor: Abdulgani Orhun YENİGÜN

STUDY PROTOCOL  
Official Title: Comparison of Bidirectional Palpation Test and 
Transit Time Flow Measurement for LIMA-LAD Graft Patency 
NCT Number: NCT06934993 
Date: 11.10.2024 
Sponsor Institution: Istanbul University-Cerrahpaşa, Faculty of 
Medicine, Department of Cardiovascular Surgery 
Ethics Approval: Approved by the Istanbul University-Cerrahpaşa 
Clinical Research Ethics Committee (approval dated 11.10.2024; 
Turkish document added to the end of the file) 

 
A. Rationale and Objective of the Study:  
The aim of this study is to evaluate the correlation between the Bidirectional Palpation Test and TTFM 
measurements, and to assess early postoperative outcomes by examining graft patency using coronary CT 
angiography. 
 
B. Main Study Form:  
 
B.1.1. General Information:  
Graft patency is one of the most critical factors determining morbidity and mortality after coronary artery 
bypass grafting (CABG). Revascularization of the left anterior descending (LAD) artery has been associated 
with improved long-term outcomes, including reduced mortality and relief of angina symptoms. The first-choice 
graft for LAD revascularization is the left internal mammary artery (LIMA). LIMA-LAD anastomosis is 
considered the gold standard due to its superior long-term patency. 
Therefore, evaluating the patency of the LIMA-LAD anastomosis is crucial for both early and long-term 
outcomes. While various methods are used routinely, many are complex and costly. The bidirectional palpation 
test, developed in our clinic, is a subjective yet simple and reliable method. In this test, after completion of 
anastomoses, temporary weaning from cardiopulmonary bypass (CPB) is performed to establish pulsatile 
pressure. A segment of the LIMA with palpable pulse is identified. In the first step, a bulldog clamp is placed 
distal to this point; continued palpation indicates antegrade flow from the subclavian artery. In the second step, 
the clamp is moved proximally; continued pulse detection indicates retrograde flow through the LIMA-LAD 
anastomosis, indirectly confirming its patency. 
Additionally, Transit Time Flow Meter (TTFM) measurements will be used as an objective method to evaluate 
graft patency. This study aims to assess the correlation between the bidirectional palpation test and TTFM with 
postoperative graft patency determined by coronary CT angiography. Within the first 30 postoperative days, 
coronary CTA will evaluate patency of the LIMA and other grafts, graft-native vessel calibration, graft position, 
sternum healing, and lung parenchyma. 
 
 
 
 
B.1.2. Materials and Methods  
 
B.1.2.1. Subjects Inclusion Criteria:  
Patients planned for CABG in our clinic will be informed and consented. Those undergoing LIMA-LAD 
anastomosis will be included. 
 
Exclusion Criteria: 
Patients at risk for contrast nephropathy and those undergoing LAD revascularization with grafts other than 
LIMA will be excluded. 
 
B.1.2.2. Methods Used in the Study  

 
a. Laboratory and Clinical Assessment Methods:  
Bidirectional palpation and TTFM measurements will be conducted intraoperatively using standard techniques, 
posing no additional surgical risk. Coronary CTA is selected as it is a non-invasive imaging method used to 
assess native coronary arteries and graft patency post-revascularization. 
 
b. Statistical Methods: 
Chi-square test, Student's t-test, Fisher's exact test, and Kaplan-Meier survival analysis for primary endpoints. 
 
C. Protocol: 
C.1. Start Date of the Study:  
April 15, 2024 
 
C.2. Duration of the Study:  
6 months 
 
C.3. Study Location:  
Istanbul University - Cerrahpaşa, Cerrahpaşa Faculty of Medicine, Department of Cardiovascular Surgery 
 
 
 
 
 
C.4. Study Investigators: 
 
Advisors: 
Prof. Dr. Suat Nail Ömeroğlu  
Dr. Çiğdem Tel Üstünışık 
 
Principal Investigator:  
Dr. A. Orhun Yenigün 
 
D. Study Outcomes, Ethics and Legal Requirements:  
 
D.1. Outcomes:  
This study is expected to reduce morbidity and mortality due to graft occlusion by allowing intraoperative 
assessment of graft flow and anastomosis quality. Revising the graft during surgery, if necessary, may prevent 
the risks and burden of reoperation. Additionally, if the bidirectional palpation test results are consistent with 
TTFM and early graft patency is confirmed via coronary CTA, this cost-free and easily applicable method may 
gain broader clinical adoption. 
 
D.2. Ethics Committee Notification: 

All necessary ethics committee notifications are planned before, during, and after the study. 
 
D.3. Data Storage and Quality Assurance:  
All records and information obtained in the study will be stored by the investigators. Personally identifiable 
information will not be included in statistical data sets; patients will be coded. 
 
E. References: 
 
1. Miguel Sousa-Uva, Franz-Josef Neumann, Anders Ahlsson, Fernando Alfonso, Adrian P Banning, Umberto 
Benedetto, Robert A Byrne, Jean-Philippe Collet, Volkmar Falk, Stuart J Head, Peter Jüni, Adnan Kastrati, Akos 
Koller, Steen D Kristensen, Josef Niebauer, Dimitrios J Richter, Petar M Seferović, Dirk Sibbing, Giulio G Stefanini, 
Stephan Windecker, Rashmi Yadav, Michael O Zembala, ESC Scientific Document Group , 2018 ESC/EACTS 
Guidelines on myocardial revascularization, European Journal of Cardio-Thoracic Surgery, Volume 55, Issue 1, 
January 2019, Pages 4–90, https://doi.org/10.1093/ejcts/ezy289 
2. Boylan MJ, Lytle BW, Loop FD, Taylor PC, Borsh JA, Goormastic M, Cosgrove DM. Surgical treatment of 
isolated left anterior descending coronary stenosis. Comparison of left internal mammary artery and venous 
autograft at 18 to 20 years of follow-up. J Thorac Cardiovasc Surg. 1994 Mar;107(3):657-62. PMID: 8127094. 
3. Sabik JF 3rd, Blackstone EH, Gillinov AM, Banbury MK, Smedira NG, Lytle BW. Influence of patient 
characteristics and arterial grafts on freedom from coronary reoperation. J Thorac Cardiovasc Surg. 2006 
Jan;131(1):90-8. doi: 10.1016/j.jtcvs.2005.05.024. Epub 2005 Dec 5. PMID: 16399299. 
4. Schmitto JD, Rajab TK, Cohn LH. Prevalence and variability of internal mammary graft use in contemporary 
multivessel 
coronary 
artery 
bypass 
graft. 
Curr 
Opin 
Cardiol. 
2010 
Nov;25(6):609-12. 
doi: 
10.1097/HCO.0b013e32833f0498. PMID: 20881486. 
5. Mujanović E, Kabil E, Bergsland J. Transit time flowmetry in coronary surgery--an important tool in graft 
verification. Bosn J Basic Med Sci. 2007 Aug;7(3):275-8. doi: 10.17305/bjbms.2007.3059. PMID: 17848157; 
PMCID: PMC5736123. 
6. Jokinen JJ, Werkkala K, Vainikka T, Peräkylä T, Simpanen J, Ihlberg L. Clinical value of intra-operative transit-
time flow measurement for coronary artery bypass grafting: a prospective angiography-controlled study. Eur J 
Cardiothorac Surg. 2011 Jun;39(6):918-23. doi: 10.1016/j.ejcts.2010.10.006. Epub 2010 Nov 20. PMID: 21095134. 
7. Lehnert P, Møller CH, Damgaard S, Gerds TA, Steinbrüchel DA. Transit-time flow measurement as a predictor 
of coronary bypass graft failure at one year angiographic follow-up. J Card Surg. 2015 Jan;30(1):47-52. doi: 
10.1111/jocs.12471. Epub 2014 Nov 3. PMID: 25363805. 
8. Niclauss L. Techniques and standards in intraoperative graft verification by transit time flow measurement 
after coronary artery bypass graft surgery: a critical review. Eur J Cardiothorac Surg. 2017 Jan;51(1):26-33. doi: 
10.1093/ejcts/ezw203. Epub 2016 Jun 13. PMID: 27298393. 
9. Kieser TM, Rose S, Kowalewski R, Belenkie I. Transit-time flow predicts outcomes in coronary artery bypass 
graft patients: a series of 1000 consecutive arterial grafts. Eur J Cardiothorac Surg. 2010 Aug;38(2):155-62. doi: 

10.1016/j.ejcts.2010.01.026. Epub 2010 Feb 21. PMID: 20176493. 
 
 
 
 
 

Ethics Committee Approval (English Translation) 
 
 
REPUBLIC OF TURKIYE 
 
ISTANBUL UNIVERSITY-CERRAHPASA 
RECTORATE 
Clinical Research Ethics Committee 
 
 
 
Ref No: E-83045809-604.01-1014609 Date: 
 
12.06.2024 
 
Subject: Research Assistant Dr. Abdullah Orhun YENIGUN Ethics Committee 
Decision 
To: Department of Cardiovascular Surgery Chairmanship 
 
Reference: Your letter dated 11.10.2024, numbered 806763 
 
Upon review of the study titled "Comparison of LIMA-LAD Graft Patency via Bidirectional Palpation Test, 
Transit Time Flow Meter (TTFM), and Coronary CT Angiography", to be conducted under the supervision of 
Research Assistant Dr. Abdullah Orhun YENIGUN, with the consultancy of Lecturer Dr. Cigdem Tel USTUNISIK 
and Prof. Dr. Suat Nail OMEROGLU, from your department, the project was discussed in our ethics 
committee meeting dated 11.06.2024 and was deemed ethically appropriate. 
 
Kindly be informed. 
 
 
 
Prof. Dr. Mehmet Sarper ERDOGAN 
Chairman 

 
Ethics Committee Approval (English Translation) 
 
Attachment: 1 hard copy of the decision will be delivered in person. 
 
 
 
This document has been signed with a secure electronic signature. 
 
 
 
Document Verification Code: BSRST3H8V2 
 
Document Tracking Address: https://www.turkiye.gov.tr/istanbul-universitesi-cerrahpasa- 
ebys 
 
 
 
For information: Hakan CENGIZ 
Extension: 23076 
 
 
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