CDU

DALLAS – Reflecting the rapid advances being made in minimally invasive procedures in cardiology, three clinician groups in November issued updated guidelines for percutaneous coronary intervention (PCI) procedures, essentially referring to balloon angioplasty.

The guidelines, unveiled in a session of the annual meeting of the American Heart Association (AHA; Dallas), update the previous guidelines issued just four years ago, thus highlighting how quickly this area of cardiovascular technology is evolving.

Importantly, the new protocol recommendations add wording related to drug-eluting stent (DES) technology, embolic protection systems and advanced imaging. Additionally, they should serve to help clinicians avoid accusations of malpractice and the potential overuse of PCI, said Sidney Smithy Jr., MD, who headed the guideline-revision committee and moderated a panel introducing the guidelines.

Smith, director of the Center for Cardiovascular Science and Medicine at the University of North Carolina (Chapel Hill), noted the emergence of emerging controversies and “hot” issues related to PCI.

He called the new protocols “exhaustive” and emphasized the breadth of input in developing the revised protocols. They represent, he said, the consensus thinking of the AHA, the American College of Cardiology (Bethesda, Maryland) and the Society for Cardiovascular Angiography and Intervention (also Bethesda).

And the writing panel included “even a [cardiovascular] surgeon – if you can believe that,” he said.

William O’Neill, MD, chairman of cardiology for the William Beaumont Hospital System (Royal Oak, Michigan), underlined the necessity of the new guidelines by asking “why should anybody be interested in this?”

O’Neill answered the question by citing a high-profile case in which the FBI had investigated physicians for Medicare fraud allegedly by performing unnecessary procedures and that investigators used the earlier guidelines to make that assessment. He also noted cases in Florida where legal reviews had been based on angioplasty guidelines.

Thus, he said, “these parameters are really incredibly important for interventional cardiology.”

Now posted on the web sites of the three organizations, the guidelines make up 122 pages, 52,503 words, 109 recommendations, 31 tables, 10 figures, 303 peer-reviewed comments," Smith said, emphasizing how thorough they are.

While a majority of the guidelines (with accompanying “list of comments”) focus on more precise use of drug therapies, there is frequent new instruction relating to the recent emergence of device systems and new imaging technologies.

An overview of the guidelines notes the updated changes with explanatory comments.

As examples, for DES devices:

• “A drug-eluting stent should be considered as an alternative to the bare-metal stent in subsets of patients in whom trial data suggest efficacy.” Comment: “Evidence continues to accumulate that supports the use of drug-eluting stents versus bare-metal stents in certain subsets in which DES results and outcomes are better.”

• “A drug-eluting stent may be considered for use in anatomic settings in which the usefulness, effectiveness and safety have not been fully documented in published trials.” Comment: “The data that a DES can improve clinical outcomes for PCI are generally strong, However, DESs have not undergone evaluation for use in all clinical situations and anatomic settings.”

• “It is reasonable to perform repeat PCI for in-stent restenosis with a DES or a new DES for patients who develop in-stent restenosis if anatomic factors are appropriate.” Comment: “clinical trials comparing sirolimus and paclitaxel DESs with PTCA for in-stent restenosis demonstrate improved outcome for the DESs.”

Another new recommendation relates to the use of radiation, saying that “brachytherapy can be useful as a safe and effective treatment for in-stent restenosis.” Smith acknowledged the appearance of this recommendation and noted that because of proof of clinical efficacy it “still is in [the guidelines] as an alternative.” But he characterized this method as “cumbersome – the whole setting-up and doing it is a much longer, complex process, logistically more difficult.” Comparatively, he noted the greater ease of using stents and their “very good” results.

Still another emerging system appearing in the guidelines for the first time is embolic protection.

• “It is recommended that distal embolic protection devices be used when technically feasible in patients underling PCI to saphenous vein grafts.” The comment notes “several studies demonstrating efficacy of distal embolic protection devices in PCI to saph-enous vein grafts.”

Other parts of the guidelines tend to underline the use of new imaging technologies, particularly intravascular ultrasound imaging (IVUS).

And a new recommendation is the “Routine measurement of cardiac biomarkers (CK-MB and/or troponin I or T) in all patients undergoing PCI eight to 12 hours after the procedure.”

Importantly, panelists presenting the revised guidelines emphasized the need for “operators” performing PCI procedures to do at least 75 per year at “high-volume” centers (those that perform more than 400 procedures annually) with “on-site cardiac surgery.”

Besides providing more exhaustive protocols for the procedure, the new guidelines generally emphasize the importance of the balloon angioplasty form of PCI and doing it quickly. They call for restoration of blood flow to the heart muscle within 90 minutes of the patient’s arrival at the hospital. “It’s an aggressive goal,” said Smith. “The science shows that patients truly benefit from a ‘door-to-balloon time’ of 90 minutes or less.”

O’Neill said that the guidelines should be carefully reviewed by physicians and administrators, “because they may be used to grade performance.”

Robotic ‘hybrid’ equals fast recovery

Combining two kinds of minimally invasive surgery (MIS) to treat diseased coronary arteries provides outcomes equal to open surgical bypass and leads to much faster recovery, according to a study presented at the AHA meeting.

Throw in robotic assistance and you’ve got a big winner for the heart patient.

That’s the very large, enthusiastically expressed hope of presenter, Marc Katz, MD, lead study author and chief of cardiac surgery and director of the Virginia Transplant Center at Henrico Doctors’ Hospital (Richmond).

But he also acknowledged major hurdles for this combination he calls a “hybrid,” including the ongoing turf war between surgeons and cardiologists.

In a roundtable sit-down with reporters prior to his presentation, Katz described a procedure for performing bypass surgery, using the fully robotic da Vinci system from Intuitive Surgical (Mountain View, California), combined with basic angioplasty and stenting performed by the cardiologist.

In the study, this combination was used to treat 27 patients, all with two diseased vessels – one of them, in all cases, an obstructed left anterior descending coronary artery (LAD), the main artery in the front of the heart. Using a closed-chest approach via the da Vinci system, the surgeons harvested the mammary artery to the obstructed LAD, bypassing the obstruction.

The other part of the treatment – sometimes days before the surgery, sometimes after it and sometimes simultaneously with it, according to Katz – was a standard angioplasty using stents – sometimes bare-metal, sometimes drug-eluting, according to the cardiologist’s preference.

The results were positive, with the arteries opened or successfully bypassed in all 27 patients, “an outcome as good or better than you would expect with open-chest surgery,” Katz said.

With that equivalence, the bigger payoff came in terms of recovery times. The open surgery requires a long incision and then cracking open the chest to get to the heart to perform the bypass, and patients are five to six days in the hospital and take weeks to recover, unable to perform laborious activities for months at a time.

But the patients receiving the “hybrid” approach required only a two- to three-day stay in the hospital and were back on their jobs – one patient following that timeline, Katz proudly noted, being a plumber.

With the “picture equals a thousand words” approach, he used a laptop to show off the da Vinci system’s unique configuration: the surgeon sitting at a console about six feet away from the surgical table, manipulating the robot’s “hands.”

These hands enter the patient’s chest through three small entry “ports.” Rather than being rigid, chopstick-like feelers, they work at the ends of mech-anical “wrists” that turn this way and that. And these hands then exactly translate the movements of the surgeons hands on joysticks, much like operating a computer game, to perform the mammary/LAD suturing. (Katz bolsters the computer game analogy by noting that only took a few minutes for his 9-year-old son to manipulate them – adding the quick assurance that his son wasn’t practicing on any patients.)

All the while, the operative field is displayed in vivid color with an endoscopic 3-D view at 10x magnification.

In response to a reporter’s question, Katz acknowledged that, yes, there’s a learning curve for the da Vinci, but a rapid one. Starting with no training in endoscopy use, he said that performed 12 of the procedures in the study and from the first to last surgery, reduced his time 60% to about 3-1/2 hours. He put that time at about equal to the comparable average open surgery.

But Katz was perhaps most emphatic in his description concerning the value of the basic mammary artery/LAD procedure itself, bannering its proven effectiveness in demonstrating patient survival. No other interventions, “not medications, not angioplasty, not stenting,” he said, have been shown as valuable as this basic treatment, that benefit backed by a track record of 15 years and more.

“It’s the single best thing, the only thing to show long-term survival benefit,” Katz said of the procedure. And he noted in particular that DES devices will have to be followed for several more years before we know if they provide any reliable data concerning survival.

While describing the effectiveness of this hybrid approach, Katz provided the usual caveat found in much initial human trial testing that the patients for the study were “picked pretty carefully.”

As to follow-up, the patients were assessed with angiograms at three months post-procedure. Twenty-six of them had wide-open bypass grafts, with one having a narrowing at the site where the graft had been sewn into the coronary artery. This was “easily opened with a balloon,” Katz said. Interestingly, nine of the patients had to have follow-up procedures for the stented arteries treated, those cases involving both bare-metal and DES devices.

All patients survived the procedures.

Katz said that he would like to continue to perform the hybrid approaches – and believes that the success of the trial should show the way for broad use of this combination. But he said that a key hurdle at some facilities would be the need for broad acceptance by reimbursers who are willing to pay for the dual procedure.

The bar is raised even higher as the result of the all-too-frequent turf battle between surgeon and cardiologist. And that battle has to be fought hardest by the surgeon, he noted, since the cardiologist most often is the main gatekeeper.

Still a third barrier to cross, in terms of this particular study, is the need for more surgeons to accept the robotic approach. That approach, he said, “takes a leap of faith – from working through an incision to sitting on the other side of the room.”

Novacor gives hope for worst kinds of HF

Serious heart failure can be reversed. Thus far, that claim has been made chiefly by the proponents of cardiac resynchronization therapy, but now the developers of left ventricular assist devices (LVADs) can make that claim as well – at least in some cases.

During an opening session of the AHA meeting, Joseph Rogers, MD, presented research on a group of patients who were implanted with the Novacor left ventricular assist device (LVAD) made by WorldHeart (Oakland, California) compared to a control group.

Rogers, associate professor of medicine and medical director of the cardiac transplant and mechanical circulatory support program at Duke University School of Medicine (Durham, North Carolina), could report that the Novacor worked exceptionally well for some, but not all, of the patients in the study.

The study followed 55 patients who were extremely ill due to heart failure and often also suffering serious co-morbidities, Roger noted. Of this group, 37 were implanted with the Novacor, and the other 18 patients were treated with intravenous heart medications to keep them alive and these served as a control group. In a press statement issued at the meeting to summarize the results, Rogers and his colleagues said that use of the Novacor “reduced the risk of death by 50% at six and 12 months and extended the average life span from 3.1 months [for the control group] to more than 10 months.” The study accumulated 30 years of support and “there were two patients on the device for more than three years.”

But the news is even better, according to Rogers, who was in charge of the pre- and post-operative care for these patients. The press statement, he told Cardiovascular Device Update in an interview following study presentation, was written at the time that the abstract for the AHA meeting was prepared. Since then, the findings have proved even more positive.

The two three-year survivors are still alive and now have passed four years supported by the Novacor LVADs. Better still, two other patients in the study were taken off the Novacor so they could receive heart transplants.

The successful bridge to transplantation for these patients is especially important, since all of those in the study were initially rejected as candidates for heart transplant, he said. They were so seriously ill that it was ruled they could not benefit from receiving a donor heart, and their rejection as candidates for transplant brought them to the Novacor study.

Supported by the Novacor, some of the patients grew less sick, improved “hemodynamically,” according to Rogers, and thus were considered able to withstand the heart transplant procedure and benefit from a donor heart.

In action, LVADs take over much of the mechanical work of the heart when medications no longer are effective. The pumping portions of the Novacor are implanted in the abdomen and are attached to the left ventricle and the main blood vessel carrying blood from the heart to the body. A tube connects the pump to an external controller and power supply worn outside the body.

Rogers acknowledged that the system did not work well for some of the patients in the study. He reported that a small number of the patients in the group implanted with the LVAD succumbed rather quickly, sometimes within the first two months after implant, the victims either of stroke – often in these cases, within a month – or infection. Thus, some died more quickly than those patients receiving IV medications, who averaged about three months of life into the study.

“There was an abrupt drop-off in survival in the LVAD arm,” Rogers said, apparently resulting from the combination of technology drawbacks and the severity of illness. Infection is a clear risk with the Novacor device, he noted, since it uses tethering that must pass from the implanted pumping portions attached to the heart, through the body to the battery. And stroke initially was related to some of the implanted driveline tubing that produced particulates that then passed into the bloodstream. That was corrected with a tubing that was more biocompatible, he said.

More broadly, he said that the study points to a broad issue in using LVADs and VADs: the difficulty in finding those patients most able to benefit from these kinds of hear support systems. “We need to refine patient selection for these pumps and work to minimize the complications associated with mechanical heart technology,” Rogers said. “Further, we need to continue to focus on new strategies for treating end-stage heart failure, which has a survival rate so low that it rivals any cancer.”

He added: “We need to find out who is likely to benefit, and who is unlikely to benefit,” adding that the most likely to benefit are those who have not yet reached the more serious, Class IV stage of heart disease. But he added: “We also have to remember there is a human being attached to the other side of that statement. These patients are often relatively young – they have children – so if you error, error on the side of giving it a try.”

Importantly, Rogers noted that there were no failures of the Novacor device in the study. But he said there is a clear need for improvement in the technology, primarily smaller batteries able to supply more power, thus enabling a device to be totally implanted. “The battery is what’s holding us back.”

Rogers said also that the Duke researchers are currently pursuing studies with other types of LVADs and VADs, such as those using axial flow pumps and still others using magnetic technologies.