Cornell University Medical College initiates study of Helionetics/AccuLase TMR system; Cornell physician says new surgical approach to treatment of heart disease 'holds the promise of being the most effective, safest and easiest laser system for doing TMR'.

NEW YORK--(BUSINESS WIRE)--Nov. 15, 1995--Cornell University Medical College has initiated a study of the Helionetics/AccuLase Excimer Laser Transmyocardial Revascularization (TMR) System.

Timothy Sanborn, M.D., chief of the medical college's Cardiac Catherization Lab, characterized TMR as "an exciting, new laser treatment for patients with coronary heart disease," adding that the Helionetics/AccuLase Excimer Laser "holds the promise of being the most effective, safest and easiest laser system for doing TMR."

The announcement was made jointly Wednesday by the medical college and Helionetics Inc. (NASDAQ:ZAPP), whose subsidiary, Laser Photonics Inc./AccuLase Inc. of Orlando, Fla. and San Diego developed the system.

The Cornell research team is led by Todd Rosengart, M.D., assistant professor, Department of Cardiothoracic Surgery; O. Wayne Isom, M.D., chairman, Department of Cardiothoracic Surgery, and Dr. Sanborn. Other surgeons participating in the Cornell program are Karl Krieger, M.D.; Samuel Lang, M.D., Nasser Altorki, M.D.; Jeffrey Gold, M.D.; Wilson Ko, M.D. and Charles Mack, M.D.

Cornell and Helionetics/AccuLase hope to complete testing of the AccuLase Excimer Laser TMR System and file an Investigational Device Exemption (IDE) to obtain U.S. Food and Drug Administration (FDA) clearance for human clinical trials during the first quarter of 1996.

According to a Bear Sterns research report, dated Jan. 27, 1995, the global market for TMR could range from more than $600 million to more than $2 billion.

Dr. Rosengart provided the following background on the AccuLase TMR procedure: "Transmyocardial revascularization (TMR) is a new surgical approach aimed at providing a source of transventricular collateral blood flow to areas of ischemic or `oxygen-starved' heart muscle.

"Although there have been continued advances in the medical and surgical treatment of coronary artery disease, there still exists a significant number of patients for whom coronary surgery is not indicated either because of diffuse atherosclerotic disease, severe small vessel coronary artery disease or multiple reoperations for coronary artery disease with poor results.

"For these patients, transmyocardial revascularization using laser energy to `drill' transmural channels, allowing intraventricular blood to bathe ischemic areas, is an alternative treatment."

Dr. Rosengart explained further: "It has been found in several previous experimental studies, and recently in human trials, that laser-created transmural channels (placed through the heart wall) can allow oxygenated blood to flow from inside the left ventricular chamber to areas of ischemia.

"The presently available technology employs a CO2 laser, which was shown to be both safe and effective in several experimental trials prior to human application. However, the CO2 laser energy must be delivered via a series of mirrors at right angles, making it quite cumbersome and restricting its use."

Dr. Rosengart continued: "The development of another type of laser, the AccuLase excimer laser, uses small flexible fiberoptics to deliver excimer laser energy (308nm).

"Although excimer laser technology has been used successfully to remove plaque from the inside of narrowed and occluded coronary arteries, this technology has yet to be tested in its ability to create and maintain open channels through myocardium.

"The flexible fiberoptics of the excimer laser offer several advantages over the CO2 laser, 1) lessened thermal effects resulting in less scarring and a more favorable healing response, 2) greater potential for long-term channel patency, and 3) the possibility of developing less invasive procedures."

The first stage of the program will be to complete preclinical testing required by the FDA. Thereafter, Cornell likely will spearhead the company's human testing program.

Dr. Rosengart added: "As stated previously, existing technology employs CO2 generated energy to create these small channels in the ventricular muscle. Efficacy of laser technology is contingent upon the degree and duration of channel patency. Several studies using the CO2 laser have demonstrated histologic evidence of prolonged channel patency ranging from 30 days to 2 years.

"In addition, many of these studies using an ischemic model were also able to show histologic evidence of decreased size of infarct, echocardiographic and improved survival as compared with appropriate controls.

"Despite the above finding, the major limitations of CO2 laser technology are: 1) inherent thermal injury causing scarring and fibrosis adjacent to the channels which may hinder increased channel patency, 2) the generation of thermal injury which could potentially injure heart valves and the conduction system, 3) steam bubbles in the ventricular cavity as a result of the CO2 laser pose the risk of air embolism and stroke, and 4) the inability to transmit the laser through flexible fiberoptics mandating a large surgical incision to expose the heart."

"In contrast, the excimer laser has been shown in early feasibility studies to employ significantly less thermal energy, resulting in less scarring and greater potential for long-term channel patency. Moreover, the excimer laser does not generate intraventricular air bubbles and minimizes the risk of stroke. Lastly, by transmitting energy via flexible fiberoptics the potential for less invasive surgery exists. While initial feasibility studies using the excimer fiberoptic laser have been performed, long term (30 day) channel patency has yet to be determined."

With specific reference to the Cornell experiments, Dr. Rosengart said: "The specific aims of this project are: 1) to demonstrate the procedural safety of the excimer fiberoptic laser for transmyocardial revascularization, and 2) to show histologic evidence of long-term (30 day) channel patency. After the above requirements are met an IDE will be submitted to obtain FDA clearance. This will then allow for future human trials."

CONTACT: Helionetics/AccuLase

Kevin Daly, 619/455-7030

OR

Cornell University Medical College

Myrna Manners, 212/821-0560