After drug-eluting stents, the cardiovascular device that has attracted the most headlines and interest over the past two years is probably the ventricular assist device (VAD), a small pump seeing growing use for bridge to heart transplant or even as a destination application.
But what if the patient is too sick to undergo the invasive surgical procedure needed to install the VAD? That is the dilemma facing older heart failure patients – as well as the dilemma faced by many others suffering severe cardiovascular trauma and needing short-term emergency support for the heart. It is a problem being directly addressed by CardiacAssist (Pittsburgh, Pennsylvania), with its TandemHeart PTVA (percutaneous transseptal ventricular assist) System, a left ventricle support device that avoids the surgical procedure of the standard VAD and provides support for a broad range of applications in acute heart failure. And it may even expand the opportunities for traditional VADs, according to Michael Garippa, company president and chief executive officer.
"Hospitals have to be prudent about use of very expensive devices and many times, from an expeditious and a cost-effective standpoint, our device makes sense before subjecting patients to the ordeal of surgical VAD implantation," Garippa told Cardiovascular Device Update. The TandemHeart PTVA is actually a combination of three systems: a pump somewhat smaller than a hockey puck, a cannula set threaded up to the heart via the femoral vein, and a control console that drives and lubricates the pump while providing system monitoring and alarms.
Garippa explained further that once the cannula is threaded to the heart, it "draws the blood out of the left atrium, goes through the pump and gets returned via another cannula in the femoral artery. Essentially it works as an atrial-to-femoral bypass system."
The pump itself, constructed primarily of metal and plastic, is external, held on the thigh in a holster, and quite powerful. It produces 4 liters of blood flow a minute and simultaneously delivers an anticoagulant drug (typically heparin) to minimize the risk of thrombus formation.
"The ability to get four liters of flow without needing surgery has never been accomplished any other way. That's the most special characteristic of the device," Garippa said. "The device can perform about 95% of left ventricle support, so the patient's heart has to do little or no work – it's almost totally at rest. No other device can do that without surgery."
The system does what traditionally has been done by an intra-aortic balloon pump, used to provide some perfusion of coronary arteries. But, Garippa said, you get "no real flow measurements from a balloon pump, and it's technically not a real pump. It gives a patient a boost that is often helpful, but not enough to support life."
The left ventricle heart assistance provided by the TandemHeart does support life, with its primary applications typically ranging from cases of cardiogenic shock to short-term support following a heart attack to both short- and longer-term support while awaiting another therapy.
In all of these applications, the TandemHeart helps to avoid associated multi-organ failure. "Our pump can and does have a big impact [reducing damage] to kidneys, liver, the brain, while off-loading the ventricle and letting it rest," Garippa said.
In such a case, the ability to install and use the TandemHeart quickly may be even more important than its ability to pump a large amount of blood. Garippa noted that the pump is installed in the cath lab, taking "under an hour, from emergency room arrival," in obvious contrast to the time required for readying a surgical procedure, even in emergency situations.
The TandemHeart received CE mark clearance in 2001 and FDA 510(k) approval in August 2003, the 510(k) clearance based primarily on a predicate device, a pump developed by Biomedicus, formerly a Medtronic (Minneapolis, Minnesota) subsidiary.
With the leadership of Dr. George Magovern Sr. of Allegheny General Hospital (Pittsburgh, Pennsylvania) and John Marous, former chairman of Westinghouse Electric – who also were co-founders of Respironics (Murrysville, Pennsylvania) – the intellectual property underlying the TandemHeart was transferred to CardiacAssist, which was then founded in 1998.
"We took [the device] out of the operating room and put it into the cath lab," Garippa said, describing the major step in the pump's development.
Garippa said that sales of the TandemHeart in Europe via a distributor network have been "fairly effective on a country-to-country basis." In the U.S., the first purchasers have been several hospitals first involved in clinical trials of the device, which have then, since 510(k) approval, purchased it "for elective use." Overall, he reported more than 300 uses of the device in 28 countries and 60 different facilities by 100 different physicians.
The key users form a prestigious roster, including William Beaumont Hospital (Royal Oak, Michigan), University of Pittsburgh Medical Center (Pittsburgh, Pennsylvania), Texas Heart Institute (Houston, Texas), LDS Hospital (Salt Lake City, Utah), Cedars Sinai Medical Center (Los Angels, California) and the Swiss Cardiovascular Center (Bern Switzerland).
Longer term, Garippa said that he expects the TandemHeart to provide an important technology for enabling both more expanded and more precise utilization of standard VADs. Priced at just $15,000, as opposed to the six-figure costs of purchasing and implanting a VAD, use of the TandemHeart, he said, enables short-term evaluation of the patient. "A VAD is a lifesaver, but you have to be healthy enough to endure the surgery," he noted.
"A number of programs are looking at our device for 'bridge to decision,' Garippa said. "Hospitals have to be prudent using very expensive devices, and our device is expeditious and cost-effective while evaluating a patient's future as compared to rushing into surgery when a patient's kidney, liver or neurologic status is undetermined. It could ultimately improve the batting average of a VAD program, since there's nothing worse than programs that successfully implant a VAD, but the patient then has multi-organ failure or is brain-dead."
The TandemHeart also can be useful "if people who don't qualify [for a VAD] can be brought up to improved status," thus enabling VAD implant. The same strategies also would apply to use of the TandemHeart for evaluating and improving patients for heart transplants, he noted, thereby improving the success of those programs.
With what Garippa terms a "prestigious list" of venture investors as backers, a "well-controlled" burn rate and reimbursement clearance already existing under DRG 104, the company expects to break even by 2005.
Longer-term, the future appears bright for the TandemHeart. CardiacAssist earlier this year won a $105,000 grant from the National Institutes of Health (Bethesda, Maryland) to modify the device for pediatric use, with early success in that effort positioning it for a follow-on $750,000 grant. And the company is readying its application to make a premarket approval application for the TandemHeart next month. PMA clearance for the pump is hoped for by late 2005 and, if won, will provide significant additional clinical support for developing even more of its potential uses.