More than 12 million Americans suffer from peri-pheral arterial disease (PAD), prompting the American College of Cardiology (ACC; Bethesda, Maryland) and American Heart Association (AHA; Dallas) to release a set of groundbreaking Peripheral Arterial Disease Guidelines to help physicians and all healthcare professionals better treat this alarmingly common condition.

PAD is generally defined as diseases of the arteries that supply blood to the arteries outside the heart, including those that supply the legs, feet, kidneys, and intestines. These arterial diseases can impair physical health by diminishing an individual’s ability to walk. PAD can lead to amputation of the extremities, rupture of an aortic aneurysm, severe hypertension, kidney failure, as well as contribute to current rates of heart attack, stroke, and cardiovascular death.

The new guidelines, representing best practices for managing diseases of the aorta – the body’s main artery – and the arteries that supply blood to the legs, feet, kidneys, and intestines, were developed in collaboration with the American Association for Vascular Surgery/Society for Vascular Surgery, the Society for Cardiovascular Angiography and Interventions, the Society of Interventional Radiology, the Society for Vascular Medicine and Biology and the ACC/AHA Task Force on Practice Guidelines.

“One of the challenges for some time has been to get public attention focused on vascular disease, which in many cases presents with silent problems,” said Brian Firth, MD, PhD, vice president of medical affairs and health economics for Cordis (Miami Lakes, Florida), which has a business unit dedicated to endovascular surgical approaches.

Firth told Cardiovascular Device Update that there isn’t the same level of awareness concerning PAD as there is with, say, angina. “Nor do you have, at this stage, clear guidelines as to what the next stage should be in terms of evaluation and treatment options,” he said. The PAD guidelines strongly emphasize the fact that early detection and treatment of PAD can prevent disability and save lives. “There’s this huge disconnect between the number of patients who have the disease and those who actually end up being investigated and treated currently,” said Firth, emphasizing that early detection is “extremely important.”

“We’re saying to physicians for the first time, ‘Don’t wait for the patient to complain to you about symptoms that they may not appreciate as hallmark signs of poor health. Ask specific questions to define high-risk groups, and initiate early therapy to maintain functional independence and decrease the risk of heart attack, stroke and death,’” said Alan Hirsch, MD, associate professor of epidemiology, medicine, and radiology at the University of Minnesota (Minneapolis), and chairman of the writing committee.

Another important element to the guidelines, according to Firth, is the fact that all of the different societies were able to come together despite their differences and come up with a consensus document. “To have something which pulls all the parties together and gives clear direction about what to do, it just seems extremely important.”

Obviously, since his company sells devices that are relevant to the disease state, “we actually see this as good too,” Firth said. “A key source of the power of these recommendations is that they are so broad-based in their origin from every vascular specialty, as they attempt to reach a broad-based audience of clinicians. Everyone can use these guidelines and a large segment of the public can benefit from them.”

Driving development of the guidelines is the fact that a wide range of physicians treat PAD, all bringing different tools and knowledge to the task, depending on background and training.

“All physicians who treat these conditions need to be aware of the latest information on diagnosis and management,” said Norman Hertzer, MD, emeritus chairman of the department of vascular surgery at the Cleveland Clinic Foundation (Cleveland). “These guidelines present that information in an objective and dispassionate fashion.”

Highlights of the guidelines include:

• Recommended questions and observations that can uncover hidden signs of peripheral arterial disease.
• Clinical clues that a patient may have renal artery stenosis, a narrowing of the arteries that supply blood to the kidney – and a possible cause of poorly controlled high blood pressure or kidney failure.
• Recommendations on when an aneurysm – a weakening and bulging of the arterial wall – should be treated with surgery or catheter-based therapy, as well as when “watchful waiting” is the best course.
• A critical analysis of the strengths and weaknesses of vascular imaging tests and other diagnostic methods.
• An emphasis on therapeutic choice, including the role of exercise, diet, smoking cessation and medications, and an objective review of the benefits and drawbacks of surgical and catheter-based therapies.
• Clinical pathways and treatment algorithms to guide clinical decision-making.

The guidelines have been developed not just for specialists who perform the complex procedures used in the treatment of peripheral arterial disease, but also for primary care physicians, nurse practitioners, and physician assistants, all of whom make the initial diagnosis and initiate therapy.

The PAD guidelines also were endorsed by the American Association of Cardiovascular and Pulmonary Rehabilitation; National Heart, Lung, and Blood Institute; the Society for Vascular Nursing; the TransAtlantic Inter-Society Consensus; and the Vascular Disease Foundation.

The ACC, AHA and all other endorsing organizations of the guidelines are partners in the PAD Coalition, a consortium of 38 health organizations, professional societies and government agencies that have united to raise public and clinician awareness of PAD.

Firth said he hopes the new PAD guidelines will serve as a stepping stone to legislation for Medicare reimbursement of early screening for asymptomatic PAD patients.

Research boosts NT-proBNP

Research presented at the 2005 scientific meeting of the American Heart Association (Dallas) suggests that the cardiac marker NT-proBNP (N-terminal pro brain natriuretic peptide) is a better predictor for mortality in heart failure patients than BNP (brain natriuretic peptide), regardless of kidney function. The research indicated that NT-proBNP is a prognostic tool for heart failure patients, in addition to being a diagnostic tool.

Among the abstracts presented at the meeting and focusing on the value of NT-proBNP were the following:

• “Combining NT-proBNP and Glomerular Filtration Rate (GFR) to Predict Prognosis in Patients with Heart Failure: An Analysis from the International Collaborative of NT-proBNP (ICON) Study.” Conclusion: that elevated NT-proBNP concentration in the presence of a low GFR strongly predicts 60-day mortality in patients with acute congestive heart failure (CHF) better than either individual parameter alone; 60-day survival was similar in patients with either a low GFR or a high NT-proBNP. The authors said that this argues against the notion that NT-proBNP is artifactually elevated by impaired GFR.

• “Concomitant Kidney Disease and Heart Failure: Diagnostic and Prognostic Utility of N-terminal proBNP and B-type Natriuretic Peptide.” Conclusion: that NT-proBNP and BNP have similar accuracy for predicting decompensated heart failure (DHF) in patients, regardless of kidney function. However, NT-proBNP is a better predictor of mortality irrespective of kidney disease (KD). Elevated NT-proBNP levels in KD patients frequently indicate underlying cardiac pathology.

• “Application of N-terminal ProBNP and B-type Natriuretic Peptide in a Large Community Cohort: Similarities and Differences for Diagnosing Heart Failure and Predicting Mortality.” Conclusion: that NT-proBNP and BNP demonstrated similar performance for diagnosing decompensated heart failure, but that NT-proBNP level is a significantly better predictor of long-term all-cause mortality than BNP, perhaps reflecting the ability to detect cardiac pathology other than DHF.

Recalls keep coming

Recalls of cardiovascular devices continued to plague the industry at the end of the year.

Boston Scientific (Natick, Massachusetts) issued two recalls in early December – one of all Stainless Steel Greenfield Vena Cava Filters with 12 Fr Femoral Introducer Systems manufactured before March 10, 2004; the second all Flextome Cutting Balloon Device Monorail Delivery System and Peripheral Cutting Balloon Microsurgical Dilatation Device Small Monorail Delivery Systems. The company said it initiated the vena cava filter recall after receiving eight complaints, two involving serious patient injury requiring intervention and one reported as a death. All unused devices with a “use before date” prior to March 2007 were to be returned, with the recall involving an estimated 18,0000 devices.

The reports described detachment at the bond between the carrier capsule and the outer sheath of the filter’s delivery system during the implant procedure. If the carrier capsule should detach during an implantation procedure, there is a risk of cardiac and pulmonary embolization..

Shortly after this, the company issued a recall of all Flextome Cutting Balloon Device Monorail Delivery System and Peripheral Cutting Balloon Microsurgical Dilatation Device Small Monorail Delivery Systems as a result of complaints and testing that showed that the distal shaft of the catheter may separate during withdrawal of the device and that a shaft separation may prolong the procedure or require additional surgery.

It said it had received a total of eight complaints, with three patients requiring follow-up surgery as a result. A total of 40,000 devices, distributed to hospitals worldwide, were to be recalled. The Cutting Balloon Device consists of an angioplasty balloon with microsurgical blades – called atherotomes – mounted to the balloon surface. As the balloon is expanded, the atherotomes score the lesions with incisions, allowing the balloon to dilate the vessel with less pressure.

Endologix (Irvine, California) later in the month said that it had launched a “limited” product recall in the U.S. of its Powerlink System delivery catheters, used to deliver the company’s minimally invasive treatment for abdominal aortic aneurysms (AAA). The recall resulted from what the company called a “comprehensive analysis” of reports of tip separation from the catheter sheath inner core during procedures. In two of the cases, it said, the Powerlink stent graft was successfully deployed and in one case the separation occurred before the device could be positioned for deployment.

The recall, the company said, does not include the Powerlink stent grafts that have been implanted in patients, and it does not include the large-diameter 34 mm Powerlink System being evaluated under an investigational device exemption or Powerlink Systems sold outside of the U.S. Both of these systems, Endologix said, utilize a different delivery catheter.

Paul McCormick, president and CEO of Endologix, termed the recall “a conservative measure in response to recent reports of tip separation. Based on our analysis, we have already identified opportunities for improvement in the assembly of these selected delivery catheters used with our Powerlink device.” He said the company would take a charge of from $700,000 to $800,000 one-quarter charge for the product consumed in the evaluation and testing and any inventory write-down.

Medtronic (Minneapolis) reported court consolidation of multiple putative class actions and individual cases arising from its recall, in February, of its Marquis implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy defibrillator (CRT-D) devices. At that time the company advised physicians concerning a potential battery shorting that could occur in a subset of implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy defibrillator (CRT-D) models.

The consolidation is to cover the pretrial period only, including Medtronic’s multiple pending motions for dismissal and summary judgment on grounds that each of the cases is legally pre-empted as a result of FDA approval of the devices. In addition, the consolidation will cover the pretrial discovery proceedings and any potential determination of class certification motions.

In late November, Medtronic also advised physicians concerning a potential separation of interconnect circuit wires that could affect a subset of its Sigma series pacemakers. The company said the incidence rate was extremely low – and it had received no reports of patient injuries or deaths – but was a conservative approach in advising the medical community and regulatory agencies. It put the incidence of the anomaly at 0.17% to 0.30% over the 10-year life of the devices. About 28,000 Sigma pacemakers were subject to the advisory worldwide, some 6,650 in the U.S.

“The risk to patients is extremely low, but we are alerting physicians to the issue to ensure they are aware of the situation and can appropriately care for their patients,” said Steve Mahle, president of Medtronic’s Cardiac Rhythm Management unit, in a company statement.