Vascular lesions

San Francisco

- Keys to successful laser treatment of vascular lesions include choosing the right tool for the task and stacking pulses appropriately, an expert says.

In treating facial telangiectasias/vascular lesions, Thomas E. Rohrer, M.D., a board-certified dermatologist with Skin Care Physicians of Chestnut Hill, Mass., says that as wavelength increases, "There is less scatter and deeper penetration. We must keep that in mind for the deeper vessels."

Intense pulsed light (IPL) devices, as well as pulsed dye, KTP and Nd: YAG lasers all can provide satisfactory results for patients with vascular lesions, he says.

But to optimize treatment with vascular lasers, "Make sure you match the pulse duration with the lesion." The larger the vessel, the longer the pulse duration, he says.

"The problem is that as we decrease our pulse durations, we increased our risk for purpura and bruising. We must find that sweet spot" that maximizes efficacy while minimizing bruising. For facial telangiectasias, he says this cutoff is about 6 ms.

Maximizing efficacy

Maximizing efficacy also requires stacking appropriately selected pulses atop one another, thereby increasing efficacy while not substantially increasing risk of purpura, Dr. Rohrer says.

"The reasons this is possible are threefold: the first is that each time you hit the vessel with a laser you will increase inter-vascular temperature. The second is that as you hit a red blood cell with a laser, it changes the shape of the red blood cell, which elongates and becomes stickier. So, your second pulse has a much denser target."

Absorption

The third reason involves the absorption profiles of oxyhemoglobin and methemoglobin. The latter absorbs 50 percent more light at 532 and 595 nm, he says.

"I usually do two to four passes over the entire vessel, then I look back to the original spot I treated to see if the vessel is still visible. If it is, I hit it again, sometimes up to four to six times."

However, he recommends stacking no more than two pulses with the 532 nm (KTP) laser because this laser absorbs more melanin than the 595 nm laser does. He also waits longer between pulses with the KTP laser.

For treating the whole face, Dr. Rohrer says he uses a 50 percent overlap to avoid creating the "honeycomb" effect in heavily vascularized areas such as the cheeks. This technique is effective with pulsed dye and KTP lasers in particular, he says.

"The problem with pulse stacking is that it dumps a lot of energy. Many patients’ skin can’t handle it," which leads to edema.

With wavelengths between 500 and 400 nm, intense pulsed light proves useful for a wide variety of lesions, adds Dr. Rohrer.

"The newer devices are very selective. They don't just give a block of light all the way across - the filter it with different hand pieces. You can get very good results with these systems in just a few treatments, rather than for treatments with the old IPL devices." DT

Disclosure:

Dr. Rohrer serves as a consultant to Candela, Solta (Reliant), Lumenis and Laserscope.