Photobiomodulation in Coronary Artery Bypass Grafting With No-Touch vs Conventional Saphenous Vein Harvesting.

Cardiovascular diseases remain one of the leading causes of morbidity and mortality worldwide. Coronary artery bypass grafting (CABG) is a widely performed surgical procedure for the treatment of advanced coronary artery disease. The saphenous vein is frequently used as a graft in CABG; however, complications related to vein harvesting, including wound infection, delayed healing, and postoperative pain, remain relevant clinical concerns.

The no-touch technique for saphenous vein harvesting has been proposed as a strategy to preserve the structural integrity of the vein and potentially improve graft patency and reduce local tissue trauma. In addition, photobiomodulation therapy (low-level laser therapy) has demonstrated beneficial effects on tissue repair, inflammation modulation, and wound healing.

This study, named PHOTON Study, is a randomized, double-blind, controlled clinical trial designed to investigate the effects of photobiomodulation therapy in patients undergoing CABG. Participants will be randomized into four groups according to the harvesting technique and the use of photobiomodulation therapy. This study protocol was developed in accordance with the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) guidelines.

Photobiomodulation will be applied using a cluster laser device (E-light, DMC Equipamentos Ltda., Brazil) with a wavelength of 660 nm and output power of 100 mW. The laser will be applied locally along the surgical incision of the saphenous vein harvesting site using a point technique with standardized spacing between application points. The intervention will be performed intraoperatively and during the early postoperative period.

The primary outcomes include wound healing and postoperative complications related to the saphenous vein harvesting site. Secondary outcomes include clinical outcomes and functional capacity following surgery.

This trial may contribute to improving postoperative care and recovery in patients undergoing coronary artery bypass grafting.

• Photobiomodulation Therapy (Device): Photobiomodulation will be applied using a cluster laser device (E-light, DMC Equipamentos Ltda., Brazil) with wavelength of 660 nm and output power of 100 mW. The therapy will be applied along the surgical incision of the saphenous vein harvesting site using a point technique with standardized spacing between application points. The intervention will be performed intraoperatively and during the early postoperative period.
• Sham Laser irradiation (Device): Simulated photobiomodulation therapy applied using the same laser device without emission of therapeutic laser energy. This sham procedure is used to maintain blinding of participants and outcome assessors.
• Conventional Saphenous Vein Harvesting (Procedure): Conventional Saphenous Vein Harvesting refers to the traditional open surgical technique used to obtain the great saphenous vein for grafting procedures, most commonly in coronary artery bypass grafting (CABG). The procedure involves a continuous longitudinal incision along the course of the vein in the lower limb, allowing direct visualization and careful dissection of the vessel from surrounding tissues. Side branches are ligated or clipped, and the harvested vein is subsequently prepared for use as a vascular graft. The technique is performed under sterile surgical conditions by qualified surgeons.
• No-Touch Saphenous Vein Harvesting (Procedure): No-Touch Saphenous Vein Harvesting refers to a surgical technique for harvesting the great saphenous vein in which the vein is removed together with a pedicle of surrounding perivascular tissue, avoiding direct manual manipulation and excessive distension of the vessel. The procedure is performed through an open incision under sterile conditions, preserving the vein's adventitia, vasa vasorum, and surrounding connective tissue in order to minimize endothelial injury and maintain vascular integrity. Side branches are carefully ligated or clipped, and the harvested graft is prepared according to institutional surgical protocols for subsequent use in vascular or coronary artery bypass procedures.

Primary outcomes

• Incidence of surgical wound complications at the saphenous vein harvesting site [From postoperative hospitalization to 30 days and 3 months after surgery.]: Occurance of one or more surgical wound complications at the saphenous vein harvesting site, including wound infection, necrosis, wound dehiscence, wound drainage or fluid accumulation.

Secondary outcomes

• Frequency and severity of adverse responses to photobiomodulation therapy [From the first photobiomodulation therapy session until hospital discharge (Postoperative day 5 or earlier, if discharged).]: Assessment of the frequency and severity of adverse reactions associated with photobiomodulation therapy during the hospital stay.
• All-cause mortality [Hospital discharge, 30 days after discharge and 3 months after discharge]: Incidence of death from any cause following coronary artery bypass grafting.
• Hospital readmission [30 days and 3 months after discharge]: Incidence of hospital readmission following coronary artery bypass grafting.
• Myocardial infarction [Perioperative, 30 days after discharge and 3 months after discharge.]: Incidence of myocardial infarction following coronary artery bypass grafting.
• Length of stay in the intensive care unit (ICU) [From date of surgery until ICU discharge (assessed up to 30 days).]: Duration of stay in the intensive care unit measured in days after surgery.
• Length of hospital stay [From hospital admission until hospital discharge (assessed up to 60 days)]: Total duration of hospital stay measured in days.
• Plasma interleukin-1 (IL-1) levels [Preoperative period, immediately after surgery before photobiomodulation application, 20 minutes after ICU admission, and on postoperative days 2 to 5 or until hospital discharge.]: Assessment of plasma IL-1 concentrations measured by enzyme-linked immunosorbent assay (ELISA).
• Plasma interleukin-6 (IL-6) levels [Preoperative period, immediately after surgery before photobiomodulation application, 20 minutes after ICU admission, and on postoperative days 2 to 5 or until hospital discharge.]: Assessment of plasma IL-6 concentrations measured by enzyme-linked immunosorbent assay (ELISA).
• Plasma interleukin-8 (IL-8) levels [Preoperative period, immediately after surgery before photobiomodulation application, 20 minutes after ICU admission, and on postoperative days 2 to 5 or until hospital discharge.]: Assessment of plasma IL-8 concentrations measured by enzyme-linked immunosorbent assay (ELISA).
• Plasma interleukin-10 (IL-10) levels [Preoperative period, immediately after surgery before photobiomodulation application, 20 minutes after ICU admission, and on postoperative days 2 to 5 or until hospital discharge.]: Assessment of plasma IL-10 concentrations measured by enzyme-linked immunosorbent assay (ELISA).
• Plasma tumor necrosis factor-alpha (TNF-α) levels [Preoperative period, immediately after surgery before photobiomodulation application, 20 minutes after ICU admission, and on postoperative days 2 to 5 or until hospital discharge.]: Assessment of plasma TNF-α concentrations measured by enzyme-linked immunosorbent assay (ELISA).
• Thiobarbituric acid reactive substances (TBARS) levels [Preoperative period, immediately after surgery before photobiomodulation application, 20 minutes after ICU admission, and on postoperative days 2 to 5 or until hospital discharge.]: Assessment of lipid peroxidation by measuring TBARS levels in EDTA plasma samples.
• Protein carbonylation (CPr) levels [Preoperative period, immediately after surgery before photobiomodulation application, 20 minutes after ICU admission, and on postoperative days 2 to 5 or until hospital discharge.]: Assessment of oxidative stress through protein carbonylation analysis.
• Functional capacity assessed by the Six-Minute Walk Test [One day before surgery, five days after surgery, 30 days after hospital discharge and 3 months after discharge.]: Functional capacity will be evaluated using Six-Minute Walk Test to assess exercise tolerance and postoperative recovery in patients undergoing coronary artery bypass grafting.

Sex: All, ages: 18 Years to 75 Years

Inclusion Criteria:

* Patients diagnosed with coronary artery disease scheduled to undergo elective coronary artery bypass grafting (CABG)
* Use of the saphenous vein as a graft for myocardial revascularization
* Ability to understand the study procedures and provide written informed consent

Exclusion Criteria:

* Emergency coronary artery bypass surgery
* Previous surgery in the lower limb that prevents saphenous vein harvesting
* Active infection at the surgical site or lower limb
* Severe peripheral arterial disease in the lower limbs
* Hemodynamic instability preventing study protocol procedures
* Participation in another interventional clinical trial that may interfere with the outcomes of this study
* Patients unable to perform postoperative functional capacity assessments
* Individuals with highly pigmented skin or sensibility that may alter light absorption and penetration of the photobiomodulation therapy.