A Clinical Trial on No-touch Vein Graft (NT-graft) in Coronary Surgery

Study Overview
=================
Brief Summary
-----------------
The primary objective in this study is to investigate if vein grafts harvested and implanted with the non-touch technique are superior to conventional vein graft technique with respect to mid-term patency, in patients undergoing CABG surgery.

Detailed Description
-----------------
Coronary artery bypass grafting (CABG) is the most common surgical procedure aimed against ischemic heart disease (IHD) in Sweden. Early and late success of CABG is the result of sustained patency of the bypass grafts. The choice of conduit (graft) for CABG has been shown to impact graft patency. The excellent early and late patency of in situ left internal thoracic artery (LITA) has stimulated the use of other arterial grafts, such as the radial artery (RA) and the right internal thoracic artery (RITA). However, target coronary vessels/lesions are limitations for the use of RITA and RA, and concerns regarding postoperative sternal wound infection with increases of early morbidity and mortality are reasons for limited use of bilateral ITA. The saphenous vein grafts (SVG), together with the left internal thoracic artery, are still the most commonly used conduits in CABG surgery. Vein graft failure is associated with recurrence of angina and one of the primary reasons for reintervention, either by redo CABG or percutaneous coronary intervention (PCI). Early vein graft failure is not uncommon, and it was shown in the PREVENT IV multi-center trial6, that vein graft failure (occluded or stenosed) had occurred in 27% of all vein grafts at one year. Despite this, SVG remains as an important conduit for most patients in contemporary bypass surgery and every effort should focus on promoting short and long-term patency of SVG. Previous studies by Souza have demonstrated that harvesting the SVG with a pedicle of surrounding tissue and without vein graft distension, the so-called No touch technique (NT), significantly improve patency compared with conventional technique i.e. stripping the vein of all adventitial tissue and distension prior to implantation. An international multi center randomized controlled clinical trial, (SUPERIOR SVG, NCT01047449) including 12 centers and 250 patients, was recently presented and showed favorable but not significant results for No touch vein grafts compared to conventional vein grafts. The protocol did not include cardiac computed tomography angiography (CCTA) for every patient which is an important difference compared to our planned study. The major limitation regarding the putative benefit of NT technique of vein harvesting is that most of the data has all been derived from a single center. The surgical vein graft harvesting technique for NT grafts is more demanding. Therefore, there is a clear clinical equipoise to perform a multi-center randomized clinical trial to validate the excellent single-center results and determine whether the NT technique is reproducible, feasible and generalizable.

Official Title
-----------------
A Nordic, Multicentre, Prospective, Randomized, Register Based, Clinical Trial on No-touch Vein Graft (NT-graft) in Coronary Surgery

Conditions
-----------------
Ischemic Heart Disease

Intervention / Treatment
-----------------
* Procedure: No touch technique
* Procedure: Control technique


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: first time CABG patients age up to 80 years at the time for inclusion need for at least one vein graft able to provide informed consent and accepted for isolated primary non-emergent CABG. Exclusion Criteria: unable to use greater saphenous vein grafts (SVG) due to previous vein stripping or poor vein quality allergy to contrast dye renal failure with glomerular filtration rate (GFR)<15 ml/min coagulation disorders excessive risk of wound infection participation in other interventional trial on grafts any condition that seriously increases the risk of non-compliance or loss of follow-up

Ages Eligible for Study
-----------------
Maximum Age: 80 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: In an online randomization module the randomization will be performed with permuted block randomization to 1:1 ratio.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: No touch<br>No touch technique. Patients are randomized to no touch vein harvesting. The technique is used as routine in Medical care by some hospitals. | Procedure: No touch technique<br>* Veins for CABG is harvested with the no touch technique<br>|
| Other: Control<br>Control technique. Patients are randomized to Control vein harvesting. The technique is used as routine in Medical care. | Procedure: Control technique<br>* Veins for CABG is harvested with the Control technique.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Saphenous vein grafts (SVGs) occluded/stenosed | The proportion of patients with graft failure defined as: SVGs occluded/stenosed >50% on CCTA or has undergone percutaneous intervention to a vein graft or died within two years after CABG. | Follow up period is from inclusion and surgery up to two years after. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Major adverse cardiac events (MACE) 1 | The frequency of incidence of all cause death | Follow up period is from inclusion and surgery up to two years after. | 
| MACE 2 | The frequency of myocardial infarction | Follow up period is from inclusion and surgery up to two years after. | 
| MACE 3 | The frequency of repeated revascularization | Follow up period is from inclusion and surgery up to two years after. | 
| Wound complications | The frequency of incidence of postoperative leg wound complications from the harvesting site. | Follow up period is from inclusion and surgery up to two years after. | 
| Vein-graft stenosis | The frequency of non-significant vein graft stenosis (20-50%) | Follow up period is from inclusion and surgery up to two years after. |