Slideshow | Ischemia-directed coronary revascularization: a cose effective role for routine cardiac magnetic resonance imaging?

Nalyaka Sambu, Christopher Turner, Stephen Harden, Charles Peebles, Nick Curzen

WASHINGTON, D.C.—Eighty-eight percent of patients being considered for revascularization were managed with optimal-based medical therapy due to the absence of significant inducible ischemia on cardiac MR, which was associated with “significant cost savings,” based on clinical research presented Sept. 22 at the Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium, sponsored by the Cardiovascular Research Foundation (CRF).

Nalyaka Sambu, MD, and colleagues from Wessex cardiothoracic unit at Southampton University Hospital in England wrote that since the COURAGE trial, the clinical pathway that leads to PCI in patients with chest pain has been the subject of “intense scrutiny.” Also, they added that data from DEFER, FAME and the COURAGE nuclear substudy make a “persuasive case for ischemia-directed PCI.”

The researchers noted the “frailty of both the exercise tolerance test and diagnostic angiogram,” questioning whether “more expensive noninvasive tests, such as stress cardiac MR, should be used routinely in stable patients.”

As a result of these questions, they sought to determine whether routine use of a “gold standard but expensive noninvasive test” of ischemia has a significant impact on the management strategy and related costs in patients being considered for revascularization.

Between January 2007 and November 2009, 150 patients presenting to a single interventionalist for consideration for revascularization were referred for stress cardiac MR with or without gadolinium. The median age of the participants was 65 years (94 percent male)—11 percent of whom had a previous positive exercise tolerance test. Also, 43 percent of patients had a raised troponin at index assessment and 45 percent had multivessel disease.

According to Sambu and colleagues, coronary angiography had been undertaken in 77 percent of the patients prior to referral for cardiac MR. The specific indication for cardiac MR in 75 percent of patients following angiography was to confirm the presence of inducible ischemia with or without viability prior to undertaking proposed revascularization by PCI (84 patients), CABG (17 patients) or either (12 patients).

They reported that ischemia was only demonstrated in 29 percent of the 113 patients, and 12 percent went onto revascularization (10 PCI, three CABG). In the remaining 20 patients, revascularization was deferred due to low burden of ischemia on the cardiac MR images.

In total, 13 revascularization procedures were performed out of 113 candidates, with an estimated financial savings of £348,366 ($545,842), after allowing for the cost of the cardiac MR exam.

As a result, the authors concluded that this “evidence-based approach resulted in considerable cost savings and avoided unnecessary patient exposure to procedural risk associated with revascularization.”

Sambu and colleagues recommended a randomized study take place because this study “demonstrates an acceptably high false-positive rate associated with exercise tolerance tests.”