Screening for Peripheral Disease No Benefit in High-Risk CAD

August 30, 2016

ROME, ITALY — Screening patients at high cardiac risk for atherosclerotic disease in other sites outside the heart did not improve 2-year outcomes in the AMERICA trial[1].

The trial was presented at the European Society of Cardiology (ESC) 2016 Congress by Dr Jean-Philippe Collet (Hôpital Pitié-Salpetrière, Paris, France).

Collet noted that current ESC guidelines give a 2a recommendation in favor of screening patients with coronary artery disease for lower-extremity artery disease with an ankle-brachial index test, but there is no hard evidence for this.

"The prevalence and associated risk of asymptomatic lesions in other arterial territories in high-risk coronary patients are unknown, and whether their systematic identification and appropriate treatment are relevant has never been established," he said.

Dr Jean-Philippe Collet

The AMERICA study therefore set out to test whether a proactive strategy of detection and management of atherothrombosis in other territories combined with an aggressive pharmacological secondary-prevention approach in a population with very high risk of coronary disease would have any benefit over the more conservative strategy of only treating symptomatic peripheral disease and standard pharmacological secondary prevention.

But results showed no difference in clinical events between the two groups.

Collet noted that atherosclerotic disease was only found in 20% of the screened group and revascularization was performed in only 1%. In addition, the control group was treated almost as aggressively as the proactive group in terms of pharmacological secondary prevention. "These factors probably explain the lack of difference in events between the two groups," he said.

He concluded that the study "has important practical implications for clinical practice."

Designated discussant of the trial at the hot-line session, Dr Valentin Fuster (Mount Sinai Hospital, New York), pointed out that the study recruited patients with very high levels of cardiac disease, but on screening they were not found to have significant peripheral disease. "They therefore had a high cardiac event rate, but few of these events would be attributed to peripheral disease, so the fact that the proactive peripheral-screening group did no better is not surprising," he said. "Maybe the results would be different if the patients had significant peripheral disease," he added.

Fuster told heartwire from Medscape: "The recommendation from this trial is if patients have a lot of cardiac disease but no symptoms of peripheral disease there is no need to screen for disease outside the heart. I would look for peripheral vascular disease only when there are symptoms."

He added that the aggressive pharmacological secondary prevention recommended in the proactive group also made little difference, as the control group were already receiving a high level of such treatment.

Another panelist at the hot-line session, Dr Stephan Achenbach (University of Erlangen, Germany), agreed. He commented to heartwire : "My take-home from this would be that atherosclerosis in different vascular beds is not very tightly connected, and it is very difficult to show a benefit of screening—that is true in medicine in general."

But ESC spokesperson at the press conference where the study was discussed, Dr François Schiele (University Hospital Jean Minjoz, Besançon, France), said he was reluctant to give up on the idea of looking for peripheral disease. "It is routine practice in my hospital to look at carotid and lower limbs with ultrasound in cardiac-disease patients. Registry studies have shown that patients with systemic disease are at higher risk, and there is a feeling that they should be treated more aggressively."

He added: "In this study they found peripheral lesions in 20% of patients, so screening might help us identify patients who need more aggressive treatment. This is a negative study, but I still think knowledge of more advanced peripheral disease is important. The trouble is that this trial recruited patients at very high cardiac risk, and many of these patients are probably already on maximal preventive therapy."

Asked if patients at lower cardiac risk had been recruited the results might have been different, Achenbach responded: "Maybe, but low cardiac risk patients probably would have an even lower risk of peripheral disease."

The AMERICA study enrolled 521 CAD patients who were considered high risk based on recently diagnosed three-vessel disease (within the past 6 months) or elderly patients (≥75 years) with acute coronary syndrome in the past month. They were randomized to a proactive prevention approach or standard care.

The proactive group received screening with total body vascular Doppler ultrasound combined with CTA or MRI if needed, with revascularization where appropriate.

They also underwent ankle-brachial index measures and creatinine clearance, fasting glycemia, and regular LDL tests, with intensive medical therapy recommended including dual antiplatelet therapy during the whole follow-up, high-dose statins, systemic beta-blockade and ACE inhibitors, antialdosterone blockade after MI if LVEF<40, and smoking cessation and rehabilitation programs.

Results showed no difference in the rate of the primary end point (all-cause mortality, rehospitalization for an ischemic event, or organ failure) at 2 years—44.9% in the proactive group vs 43.0% in the conservative arm (hazard ratio [HR] 1.03; 95% CI 0.80–1.34), reported Collet.

Similarly, there were no significant difference in the rate of the main secondary end point: a composite of all-cause death, MI, stroke, and any revascularization. This occurred in 12.9% of the patients in the intensive group and 13.6% of those in the conventional group (HR 0.94; 95% CI 0.58–1.50).

Major bleeding events also occurred at a similar rate (4.6% vs 5.0% respectively; HR 0.97; 95% CI 0.40–1.91).

The AMERICA trial was funded by Assistance Publique des Hôpitaux de Paris and funded by the Institut de l'Athérothrombose. Collet receives research grants from Bristol-Myers Squibb, Sanofi, Eli Lilly, Guerbet Medical, Medtronic, Boston Scientific, Cordis, Stago, Centocor, Fondation de France, INSERM, Federation Française de Cardiologie, and Société Française de Cardiologie; consulting fees from Sanofi, Eli Lilly, and Bristol-Myers Squibb; and lecture fees from Bristol-Myers Squibb, Sanofi, and Eli Lilly.

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