The FAME 1&2 Trials | Cardiac Health

In 1995 Topol[1] first described what vascular surgeons have known for many years:

The pressure drop in a fluid flowing through a long cylindrical pipe such as a stenotic artery becomes functionally significant when the obstruction exceeds 70%, first described in the Poiseuille law in 1846[2].

As was stated in Topol’s paper: “Accordingly, before the residual stenosis in an infarct vessel is addressed, there should be demonstration of either spontaneous or provocable signs of ischemia… clinicians and investigators rely excessively on angiography for clinical decision-making… Procedures should not be performed solely to improve the luminal appearance—so-called coronary “cosmetology”.

This principle was tested with the PCI Fractional Flow Reserve FAME 1[3]&2[4] trials:

PCI was superior to Optimal Medical Therapy only in stenotic lesions with hemodynamically significant flow restrictions (FFR<80%).
Among patients with stenoses that were not functionally significant (FFR >0.80), the best available medical therapy alone resulted in an excellent outcome, regardless of the angiographic appearance of the stenoses.

Topol:

“The term “oculostenotic” reflex was coined to denote what appears to be an irresistible temptation among some invasive cardiologists to perform angioplasty on any significant residual stenosis after thrombolysis. Although this approach is not supported by the American College of Cardiology and American Heart Association guidelines, the ritual of reflex angioplasty is exercised thousands of times each year. Systematic functional assessment in patients after successful reperfusion suggests that fewer than half will have objective evidence of provocable ischemia. Importantly, a randomized trial of patients with a negative functional test but a significant infarct vessel stenosis demonstrated worse outcome in the group assigned to angioplasty.”

Comment:

A strategy of reflex PCI during routine coronary angiogaraphy has only recently become less common. It is not known how many non-ischemic lesions are stented in day-to-day practice, but these results suggest a high percentage!

Dr T

[1] Our Preoccupation With Coronary Luminology. The Dissociation Between Clinical and Angiographic Findings in Ischemic Heart Disease, Topol et al; Circulation. 1995; 92: 2333-2342.

[2] The Hagen–Poiseuille equation.

[3] Fractional Flow Reserve Versus Angiography for Guiding Percutaneous Coronary Intervention in Patients With Multivessel Coronary Artery Disease, Nico H.J. Pijls, MD et al; J Am Coll Cardiol. 2010;56(3):177-184.

4 Fractional Flow Reserve–Guided PCI versus Medical Therapy in Stable Coronary Disease, Bernard De Bruyne, M.D., Ph.D. et al: N Engl J Med 2012; DOI: 10.1056/NEJMoa1205361.