Appraising the pathophysiologic impact of coronary collaterals as measured by fractional flow reserve on symptoms and signs of myocardial ischemia.
BACKGROUND
The purpose of coronary revascularization in stable patients is anginal relief, yet there is no linear relationship between stenosis severity and clinical significance. A major factor in this complex lesion-myocardium interaction is collateral flow. We aimed to define which collateral flow cut-offs separate asymptomatic from symptomatic patients during coronary occlusion.


METHODS
Patients undergoing percutaneous transluminal coronary angioplasty for a single stenotic lesion were selected, collaterals were appraised angiographically, and fractional flow reserve was used during prolonged balloon occlusion to measure collateral flow index (FFRcoll). Changes in anginal symptoms, ST-T segment, and left ventricular wall motion were appraised before and during/shortly after balloon dilation. Receiver-operating-characteristic curves and area under the curve were computed to identify the most appropriate FFRcoll cut-offs.


RESULTS
Twenty consecutive patients were enrolled. At baseline, 10 patients had angiographic evidence of collaterals, whereas 10 had no angiographic evidence of collateral flow distal to the target lesion. FFRcoll had an excellent discriminatory performance for the presence of angiographic collaterals (area under the curve = 0.90, P = 0.003), a good discriminatory performance for the occurrence of angina (area under the curve = 0.80, P = 0.025), and a trend toward a good discriminatory performance for the occurrence of asynergy (area under the curve = 0.81, P = 0.06). On the basis of receiver-operating-characteristic curves, an FFRcoll cut-off greater than 0.26 could reliably distinguish patients with adequate collaterals (sensitivity = 0.90, specificity = 0.80), whereas a greater than 0.41 cut-off distinguished patients having angina or wall motion abnormalities from those remaining asymptomatic.


CONCLUSIONS
This study shows that distal collateral pressure greater than 41% of proximal perfusion pressure protects from anginal symptoms or regional systolic dysfunction during coronary occlusion, whereas a greater than 26% cut-off is more appropriate to identify angiographically evident collaterals ensuring distal myocardial viability.
Division of Cardiology, University of Turin, Turin, Italy.
Claudio
C
Moretti
Giuseppe Gl
GG
Biondi-Zoccai
Filippo
F
Sciuto
Pierluigi
P
Omedè
Maria Teresa
MT
Lucciola
Luisa
L
Morena
Walter
W
Grosso Marra
Gian Paolo
GP
Trevi
Imad
I
Sheiban
D000368:Aged; D000787:Angina Pectoris / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy; D015906:Angioplasty, Balloon, Coronary; D021721:Balloon Occlusion; D001794:Blood Pressure; D003097:Collateral Circulation; D017023:Coronary Angiography; D023921:Coronary Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy; D004562:Electrocardiography; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve