Non-invasive cardiac screening in patients with peripheral arterial disease: the GROUND study.

Background:
Patients with peripheral arterial disease (PAD) have a considerably increased risk of coronary events. The majority of PAD patients die from coronary artery disease. Non-invasive cardiac imaging offers the possibility to assess presence of severe coronary atherosclerosis and /or cardiac ischemia and may further help to identify those PAD patients at very high risk of coronary artery disease.
Furthermore, providing tailored medical care to PAD patients with cardiac abnormalities may actually reduce risk and prevent events.

Objective:
To evaluate whether minimal invasive cardiac imaging, followed by subsequent medical treatment reduces the 5-year risk of cardiovascular events in cardiac asymptomatic patients with PAD.
Design: Multicenter randomized controlled clinical trial.

Methods:
Patients with PAD and no history of coronary artery disease will all be subjected to cardiac imaging using non-invasive cardiac computed tomography (CT). Next, patients will be randomized to either undergo usual medical care or to be actively referred to a cardiologist based on the findings of cardiac imaging. In the latter group, patients will undergo computed tomography angiography (CTA) additionally.
Those patients with a coronary stenosis of the left main coronary artery (or its equivalent) of 50% or more will be referred to a cardiologist for appropriate treatment.
Those with a left coronary artery stenosis of less than 50% will be scheduled for a dobutamine stress magnetic resonance imaging (DSMR) test to assess cardiac ischemia.
Patients with cardiac ischemia will be referred for appropriate medical care to a cardiologist, whereas those without cardiac ischemia will be followed for the occurrence of future cardiovascular events. The occurrence of these events, i.e. the combination of fatal and non-fatal coronary heart disease and stroke, will be monitored in both groups. Sequential interim analyses on events will be performed by an independent Data Safety and Monitoring Board.
The main efficacy analyses will be performed using a Kaplan Meier model based on the intention-to-treat population. A sample size calculation estimated that 1200 patients have to be enrolled in the GROUND study in order to detect a relative risk reduction of 24% between the two groups.

Conclusion:
The present study will provide insight into the question whether non-invasive cardiac imaging reduces the risk of cardiovascular events in patients with PAD but yet without symptoms of coronary artery disease.

Screening of asymptomatic coronary artery disease using non-invasive modalities in patients with manifestations of atherosclerosis, ie peripheral arterial disease, and subsequent treatment will result in a reduction of cardiac morbidity and mortality.

Patients randomized to the control group will ondergo a CT scan to determine the coronary calcium score;
Patients in the intervention group will undergo a CTscan for calcium score, and a contrast enhanced CT scan for the evalluation of coronary stenosis.
If no stenosis is found a dobutamine stress MRI of the heart will be performed to identify myocardial ischemia.
If a stenosis is found on either diagnostic test, the patient will be referred to the cardiologist, who will decide if and which treatment he will give the patient for the encountered coronary stenosis.