Amid what it said is growing evidence that coronary artery bypass grafting (CABG) surgery on the beating heart is safe, effective and easier on the patient than conventional CABG surgery with a heart-lung machine, Medtronic (Minneapolis, Minnesota) last month released its next-generation tissue stabilization device, called the Octopus 4, which is designed to make surgical techniques on the beating heart easier, a necessity for the widespread adoption of the procedure. The Octopus 4 device, so named for its suction capabilities, will be paired with another next-generation system, the Starfish 2 heart positioner, which was launched in May.

Together they make up the Octopus System II, which Medtronic said features added flexibility and lower profiles over the older Octopus system that should improve the surgeon's access to, and view of, target arteries on any surface of the heart.

The Octopus 4 stabilizer attaches to the heart with suction to gently hold small areas of cardiac surface tissue nearly motionless, to provide stabilization as the surgeon sutures grafts that bypass artery blockages.

According to the company, the overall reduced profile of the new system minimizes clutter in the surgical field, while the downsized control components, the turret and a single vacuum line reduce obstructions for the surgical team.

Medtronic spokesman Bob Hanvik said that advances in off-pump technology such as the Octopus system will contribute to an uptake in this type of CABG procedure. He told Cardiovascular Device Update that the total time of the procedure is generally shorter than that of the on-pump CABG. And, while there have been no actual studies comparing the cost of the two procedures as of yet, he said that doctors have indicated "since you're spending less time in OR and less time in the ICU, it's going to be less expensive."

Some surgeons believe that beating-heart surgery represents a major medical advancement in CABG procedures because it eliminates the need for an external perfusion circuit – the pump or heart-lung machine – which pumps oxygenated blood through the body when the heart must be stopped for repairs. Use of this perfusion circuit has been the gold standard for more than three decades. However, because of its complexity and potential risks, combined with the accumulating positive outcomes data about patients who have undergone beating-heart surgery, an increasing number of surgeons are opting to avoid the perfusion circuit when possible. Use of beating-heart techniques has grown more than 40% each year since 1997. It is estimated that 20% to 25% of the 350,000 CABG procedures that take place annually in the U.S. are now performed off-pump.

Heightened interest in beating heart surgery, which is associated with less blood loss than surgery with the perfusion circuit, has coincided with shortages of banked blood across the nation, as well as increased costs of transfusions and the risk of bloodborne diseases. John Puskas, MD, a cardiac surgeon at Crawford Long Hospital of Emory University (Atlanta, Georgia), reported in the Annals of Thoracic Surgery that, while 70% of 200 CABG patients who underwent surgery with the perfusion circuit required transfusions, only 33% of beating-heart patients required banked blood. Another study of 8,400 patients, supporting those results, was published in the same journal, with Mitchell McGee, MD, of the Cardiopulmonary Research Science and Technology Institute (Dallas, Texas) as the lead author.

Puskas said that results of the 200-patient study – which used the prior-generation Octopus 3 device – titled Surgical Management of Arterial Revascularization Therapies (SMART) was blinded. None of the patients, post-operative caregivers or study evaluators knew which of the patients had received the beating-heart procedure or the traditional approach.

Compared to the conventional stopped-heart CABG procedure, he said patients undergoing the procedure off-pump achieved similar levels of revascularization, similar inpatient and post-hospital outcomes and had reduced transfusion requirements.

The beating-heart procedure showed some clear benefits as well, he said. Overall, beating-heart patients had less damage to the heart muscle as a result of the surgery. "These patients also had a shorter length of stay as inpatients and had less myocardial injury than conventional CABG patients," Puskas said at a May meeting in Washington of the American Association for Thoracic Surgery (Philadelphia, Pennsylvania).

Larry Haimovitch, president of Haimovitch Medical Technology Consultants (Mill Valley, California), who follows the cardiovascular sector for CDU and its sister publication, Medical Device Daily, has a wait-and-see view. He noted that that while the percentage of off-pump CABG procedures has increased from 0% to about 20% in the past five years, that number appears to have stalled out recently. "I think it's in part technology issues and in part the fact that it's not really applicable to every procedure," he said. Haimovitch said that cardiovascular surgeons, who perform the majority of CABG procedures, "are probably as conservative of an audience as you'll find." These surgeons, he noted, want more long-term data – five to 10 years – showing that beating-heart revascularizations are holding up as well as those performed via on-pump procedures before they will be willing to make a change, and that data is not available for the off-pump procedures yet.

Haimovitch added that the procedure is more technically demanding for the doctors. "It's a whole lot better for the patient and more difficult for the doctor," he said, noting that the doctors are working in smaller spaces and also must work with an organ – the heart – that is now moving about. However, he expressed optimism that the beating-heart sector will grow, fueled by earlier training in minimally invasive techniques for surgeons entering the vascular field, along with "improvements in technology and long-term results showing that vessels are staying patent for 10 or 15 years." He said that Guidant (Indianapolis, Indiana), St. Jude Medical (St. Paul, Minnesota) and perhaps Johnson & Johnson (New Brunswick, New Jersey) also are working on for use in beating-heart CABG surgery.

Medtronic said that many of the concerns raised by skeptical doctors have been or are being addressed through various studies. The company said that early and mid-term rates of unobstructed flow after beating-heart CABG surgery have now been shown by several studies to be equal to or better than those of traditional pump techniques. In a study of 90 patients, a team headed by W. Douglas Boyd, MD, at London Health Sciences Center at the University of Western Ontario (London, Ontario) found 100% of all grafts performed on the beating heart stayed open. Similar results came from an Italian team headed by Antonio Calafiore, MD, at the University G. D'Annunzio (Chieti, Italy).

Albert Pfister, MD, of Washington Hospital Center (Washington), said, "the outcomes we're seeing [with technology advances such as the new Octopus system] give us added assurance that CABG surgery on the beating heart is the preferred approach for a growing number of our patients."

In other product news:

Abiomed (Danvers, Massachusetts) said Tom Christerson, who has survived nearly a year with its AbioCor artificial heart, returned home after undergoing surgery to replace the device's lithium battery. Christerson was admitted in mid-July to Jewish Hospital (Louisville, Kentucky). His post-surgery duration in the hospital was not disclosed, but he has since returned to his home in Central City, Kentucky. Christerson has lived with the self-contained artificial heart since Sept. 13, the longest of any of the seven recipients of an AbioCor heart.

Arrow International (Reading, Pennsylvania) reported an additional U.S. implant of its LionHeart, a fully implantable Left Ventricular Assist System (LVAS). The implant, the eighth overall in the U.S., is the first in a new series of seven authorized by the FDA as a continuation of a Phase I trial. In Europe, the total number of LionHeart implants remains at 25. Arrow said European patients living with the device continue to do well, with five now sustained by the LionHeart for more than a year. The device is fully implanted in the body and does not replace the heart, but assists in the left ventricle's pumping function.

Boston Scientific (Natick, Massachusetts) said six of the seven premarket approval (PMA) modules submitted to the FDA for its EPT-1000 XP cardiac ablation system for the treatment of atrial flutter have been reviewed, accepted and closed by the agency. The seventh and final module is currently under review, the company said. Boston Sci filed its application with the FDA in the second quarter. The EPT-1000 XP system uses radiofrequency (RF) to treat the condition by creating a linear lesion across the tricuspid isthmus, interrupting the abnormal electrical circuit causing the atrial flutter and allowing the heart to return to normal rhythm. The company said traditional approaches to treating atrial flutter are palliative and the arrhythmia may require alternative treatment. Boston Scientific's system consists of a family of Blazer II XP bi-directional, temperature-controlled cardiac ablation catheters and the EPT-1000 XP generator. The forthcoming version of the generator will increase the available RF power level from 50 watts to 100 watts.

CardioDynamics (San Diego, California), a developer of Impedance Cardiography (ICG) technology, signed a co-development and OEM agreement with Philips Medical Systems (Andover, Massachusetts) to combine CardioDynamics' ICG technology with Philips' diagnostic 12-lead technology. ICG technology provides clinicians with noninvasive comprehensive data regarding the heart's mechanical characteristics, while ECG provides data regarding the heart's electrical characteristics. CardioDynamics said the combination is aimed at enhancing diagnostic testing to provide a more complete assessment of a patient's clinical condition.

Guidant (Indianapolis, Indiana) said the FDA approved six-month follow-up clinical trial results for its Multi-Link Pixel Coronary Stent System. Data demonstrated safety and efficacy, with a target lesion revascularization rate of 8% at 180 days. Target vessel failure at 30 days, the trial's primary endpoint, was 1.3%. The Multi-Link Pixel registry involved 150 patients treated for abrupt or threatened abrupt closure of first-time or recurring blockages in small-diameter vessels of 2 mm to 2.5 mm, with mean reference vessel diameter of 2.14 mm. Results showed a 100% procedural success rate, with a 180-day major adverse cardiac event rate of 10.2% and a 180-day target vessel failure rate of 13.6%. Mean lesion length was 10.21 mm, and 36% of those enrolled in the trial were patients with diabetes mellitus. Guidant also received FDA clearance for its Endotak Reliance active-fixation defibrillation lead. Endocardial defibrillation leads are thin, insulated wires that connect an implantable cardioverter defibrillator (ICD) to the heart. The lead transmits signals from the heart to the ICD device and, when appropriate, delivers therapy from the ICD back to the heart. According to the company, the lead can combine with a Ventak Prizm 2 implantable defibrillator to provide a small, thin system to treat dangerous or irregular heart rhythms.

MicroVention (Aliso Viejo, California) received FDA 510(k) and CE mark clearance for its HydroCoil Embolic System to treat cerebral aneurysms. The HydroCoil is an endovascularly placed embolization device combining an expandable microporous polymer with platinum microcoil technology. It combines the safety and ease of use of platinum coils with the filling and healing properties of the expandable polymer. The HydroCoil offers a new therapeutic alternative to the current treatment choices: platinum coil embolization and neurosurgical clipping. The company added that physicians have treated the first 35 patients with its HydroCoil for the treatment of cerebral aneurysms. Initial research suggests the HydroCoil could effectively treat a broad range of cerebral aneurysms. The company also announced the start of enrollment in the HEAL (HydroCoil for Endovascular Aneurysm occLusion) post-market study, which plans to evaluate approximately 200 patients at 20 domestic and international neurovascular centers.

Rubicon Medical (Salt Lake City, Utah) reported plans for a clinical study of its Rubicon Filter in Europe to gain CE mark approval. The study will test the filter in saphenous vein grafts, which are degenerated coronary bypass grafts in which blockages have reappeared following heart bypass surgery. The company said it expects to begin clinical studies in either 4Q02 or 1Q03. The studies are expected to take three to four months. Rubicon said it plans to begin the FDA approval process following the European studies. The embolic filter is designed to be inserted into a blood vessel and allow blood to continue flowing during a surgical procedure, while blocking any particle large enough to cause damage to the body. The Rubicon Filter is designed to prevent or reduce the possibility of serious or fatal embolization caused by particles loosened during surgery.

World Heart (Oakland, California) submitted to the FDA a premarket approval supplement for use of Novacor LVAS, its left ventricular assist system, by end-stage heart-failure patients who are not candidates for heart transplantation. WorldHeart requested expedited review. The Novacor LVAS was approved in September 1998 for use as a bridge to transplantation in the U.S. There is no assist device approved in the U.S. as destination therapy for heart-failure patients. The submission is based in part upon a Bayesian statistical analysis, which in summary concluded the Novacor LVAS is an extremely reliable device, with a record of more than a decade of use by end-stage heart-failure patients. WorldHeart's Novacor LVAS is an electromagnetically driven pump that provides circulatory support by taking over part or all of the workload of the left ventricle. It is approved in Europe without restrictions for use by heart failure patients.