Interventional cardiologists — and nurses — probably know well the problems associated with contrast-induced nephropathy (CIN) in cath labs.

CIN is a condition whereby nephrons, or cells specific to the kidneys that filter those organs, are seriously injured or damaged by contrast media, reducing their ability to function. And as procedures such as angioplasty and drug-eluting stent placements become more common, CIN is likely to increase — and with it the mortality related to CIN.

PLC Medical Systems (Franklin, Massachusetts) — previously best known for its development of a laser system to treat angina — believes it has developed a solution to the problem. And it has completed enrollment of the first three patients in its FDA-approved pilot clinical trial designed to evaluate the safety of its RenalGuard System, the name very clearly indicating the systems purpose: protecting the renal system.

Therapy using RenalGuard is intended to reduce the incidence of CIN by managing real-time fluid balance and diuresis in conjunction with interventional procedures, such as percutaneous coronary intervention (PCI) and other radiology procedures requiring contrast media.

The system in real-time — or "minute-by-minute, milliliter-by-milliliter," according to the company — involves using a device to measure the urine collected via a catheter. Then that same device signals the system to pump the same amount of "normal saline" back into the patient via an IV to ensure that the patient does not become dehydrated with the additional loss of urine.

The therapy is based on preclinical study data supporting the theory that initiating and maintaining high urine output allows the body to rapidly eliminate contrast, reducing its toxic effects.

"Science tells us that if you can get a patient to produce a lot of urine and that patient always has enough fluid," then the effect of the contrast medium is "minimized," Mark Tauscher, president of PLC, told Medical Device Daily.

A diuretic is given to the patient before the cath procedure, and the RenalGuard therapy is then initiated — also before the procedure begins — and ends when the patient is able to leave the lab, Tauscher said.

Safety results have been "favorable," according to the company, and there have been no adverse events related to the device.

Tauscher told MDD that "studies have shown that patients who get contrast-induced nephropathy have a higher probability of dying within one year" than patients who don't develop the condition following administration of a contrast medium.

The FDA granted the company an investigational device exemption in December to test 40 patients in four centers, and since then the company has been "aggressively and actively screening" to enroll patients, Tauscher said.

The first procedures in the study, all done in conjunction with a percutaneous coronary intervention (PCI) employing multiple stents, were performed by Richard Zelman, MD, at Cape Cod Hospital (Hyannis, Massachusetts).

"The use of RenalGuard Therapy maintained a high level of urine output, which is believed to reduce potential renal toxicity by protecting the kidney during interventional cardiac procedures requiring contrast media," said Zelman. "The system operated smoothly and did not change the flow of the catheterization procedure. The patients' procedures were completed successfully and the patients experienced no adverse renal complications."

Tauscher said that completion of the first procedures "gives us confidence that we will complete this pilot trial successfully."

He said the patients who are the best candidates for RenalGuard therapy are the "classic cardio cath" patient, those in the 55-80 age group with a bad heart. RenalGuard targets those patients.

About 7 million patients worldwide undergo interventional therapeutic and diagnostic procedures each year, and CIN is a growing problem due to the increasing number of older patients, diabetics and patients with pre-existing renal failure.

CIN is the third most common cause of in-hospital acute renal failure. It is associated with significant in-hospital mortality rates, and increases in long-term mortality, major in-hospital adverse cardiac events and risk of renal dialysis therapy.

Any of these can result in prolonged hospital stays and increased medical costs. Studies indicate that about 15%-20% of all patients undergoing image-guided cardiology and radiology procedures are at risk of developing CIN, and the estimated mortality for patients that acquire CIN is as high as 35%.

In addition to RenalGuard, PLC is the developer of the CO2 Heart Laser System, which cardiac surgeons use to perform CO2 transmyocardial revascularization (TMR) to alleviate symptoms of severe angina.

The company says that CO2 TMR offers a treatment option for angina patients who suffer from severe coronary artery disease. The CO2 Heart Laser is the world's first TMR angina relief device approved by both the FDA and Japanese Ministry of Health, Labor and Welfare, and to obtain a CE Mark for European distribution, PLC says.

Tauscher said there is no real "synergy" between the RenalGuard therapy and the CO2 Heart Laser System, except that they both are targeted to large markets.

PLC Medical licensed some of the intellectual property to develop RenalGuard, and then the company completed the system internally, Tauscher said.

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