Low-level laser therapy prevents prodromal signal complications on saphenectomy post myocardial revascularization

Experimental and Clinical Applications of Red and Near-Infrared Photobiomodulation on Endothelial Dysfunction: A Review

BACKGROUND

Under physiological conditions, endothelial cells are the main regulator of arterial tone homeostasis and vascular growth, sensing and transducing signals between tissue and blood. Disease risk factors can lead to their unbalanced homeostasis, known as endothelial dysfunction. Red and near-infrared light can interact with animal cells and modulate their metabolism upon interaction with mitochondria's cytochromes, which leads to increased oxygen consumption, ATP production and ROS, as well as to regulate NO release and intracellular Ca²⁺ concentration. This medical subject is known as photobiomodulation (PBM). We present a review of the literature on the in vitro and in vivo effects of PBM on endothelial dysfunction.

METHODS

A search strategy was developed consistent with the PRISMA statement. The PubMed, Scopus, Cochrane, and Scholar electronic databases were consulted to search for in vitro and in vivo studies.

RESULTS

Fifty out of >12,000 articles were selected.

CONCLUSIONS

The PBM can modulate endothelial dysfunction, improving inflammation, angiogenesis, and vasodilatation. Among the studies, 808 nm and 18 J (0.2 W, 2.05 cm²) intracoronary irradiation can prevent restenosis as well as 645 nm and 20 J (0.25 W, 2 cm²) can stimulate angiogenesis. PBM can also support hypertension cure. However, more extensive randomised controlled trials are necessary.

Effectiveness of Low-Intensity Laser Therapy on Tissue Repair Following Saphenectomy in Patients Who Underwent Coronary Artery Bypass Graft: A Randomized, Double-Blind Study

OBJECTIVE

To verify the effectiveness of low-intensity laser therapy (LLLT) on tissue repair following saphenectomy during postoperative period in patients having undergone coronary artery bypass graft (CABG).

MATERIALS AND METHODS

A randomized clinical trial, controlled and double-blind study was conducted with 40 volunteers, divided into 2 groups: a placebo group (PG, n = 20) and a laser group (LG, n = 20). The patients in the LG group were irradiated with laser during saphenectomy (InGaAlP, λ 660 nm, energy density 6 J/cm²) daily from the first to the fourth postoperative day. The surgical incision was clinically evaluated and imaged at the beginning and at the end of the treatment. The areas of hematoma and hyperemia were evaluated using the software ImageJ 1.4^©, and border closure was evaluated by three researchers, who were blinded concerning the allocation of the participants.

RESULTS

The LG group presented a reduction of the areas of hematoma and hyperemia (p = 0.0003) and better border closure (p = 0.009), when compared with the PG group.

CONCLUSIONS

The proposed LLLT protocol improved the tissue repair following saphenectomy in CABG patients.

Low-intensity laser (660 NM) has analgesic effects on sternotomy of patients who underwent coronary artery bypass grafts

Background:

The aim of this study was to evaluate the efficacy of low-level laser therapy for reducing the acute pain of sternotomy in patients who underwent a coronary artery bypass graft (CABG).

Methods:

This study was conducted with ninety volunteers who electively submitted to CABG. The volunteers were randomly allocated into three groups of equal size (n = 30): control, placebo, and laser (λ of 660 nm and spatial average energy fluency of 1.06 J/cm²). Pain when coughing was assessed by a visual analog scale (VAS) and McGill Pain Questionnaire, according to sensory, affective, evaluative, and miscellaneous domains. The patients were followed for 1 month after the surgery.

Results:

The laser group had a greater decrease in pain with analogous results, as indicated by both the VAS and the McGill questionnaire (P ≤ 0.05) on sensory and affective scores, on days 6 and 8 postsurgery compared to the placebo and control groups.

Conclusion:

Laser seems to be effective promoting pain reduction after coronary-arterial bypass grafting.

Photobiomodulation (Laser and LED) on Sternotomy Healing in Hyperglycemic and Normoglycemic Patients Who Underwent Coronary Bypass Surgery with Internal Mammary Artery Grafts: A Randomized, Double-Blind Study with Follow-Up

BACKGROUND AND OBJECTIVE

This study aimed at analyzing the healing effects of low-level laser therapy (LLLT) (λ620 nm, 6 J/cm²) and light-emitting diode (LED) therapy (λ640 nm, 6 J/cm²) on the longitudinal sternotomy incisions of hyperglycemic and normoglycemic patients who underwent coronary artery bypass grafting (CABG).

MATERIALS AND METHODS

120 volunteers were electively submitted to CABG and were randomly allocated into four different groups of equal size (n = 30): control, placebo, laser (λ of 640 nm and spatial average energy fluency [SAEF] of 1.06 J/cm²), and LED (λ of 660 ± 20 nm and SAEF of 0.24 J/cm²). Laser and LED groups were irradiated from the second to eighth day postsurgery, and sternotomy incision was photographically registered. Then, participants were also separated into hyperglycemic and normoglycemic groups, according to their fasting blood glucose test before surgery. Three researchers blindly analyzed the incision photographs to determine hyperemia and wound closure at the first day of hospital discharge (eighth postoperative day).

RESULTS

LLLT and LED groups had similarly less hyperemia and less incision bleeding or dehiscence (p ≤ 0.005) and the outcomes were also analogous between hyperglycemic and normoglycemic patients, which indicates no difference observed in an intragroup analysis (p ≥ 0.05).

CONCLUSIONS

With the present therapy parameters, it may be assumed that both coherent light (laser) and non-coherent light (LED) are effective in promoting sternotomy and healing acceleration, which are evident on the eighth day postsurgery.