IVUS / Jasti

Correlations between fractional flow reserve and intravascular ultrasound in patients with an ambiguous left main coronary artery stenosis.

Jasti V, Ivan E, Yalamanchili V, Wongpraparut N, Leesar MA.

Circulation. 2004 Nov 2; 110(18):2831-6.

OBJECTIVES:

The aim was to determine the cutoff values of several IVUS parameters that would predict the physiological significance of the LMCS. An additional aim was to determine, among patients with an ambiguous LMCS, the prognostic value of an FFR cutoff of 0.75 that would determine whether to proceed with medical therapy or revascularization.

METHODS:

• 55 patients
• Single center
• Angiographically ambiguous LMCS
• A pressure guidewire was used to calculate FFR
• IVUS parameters were calculated after automatic pullback
• Cardiac events included death, myocardial infarction, CABG, and PCI related to the LMCS or native coronary artery

SUMMARY:

• FFR averaged 0.86 ± 0.13 (range, 0.55 to 1.0).
• IVUS Minimum Lumen Diameter (MLD) was 3.8 ± 0.61 mm.
• Minimum Lumen Area (MLA) averaged 7.65 ± 2.9 mm².
• Cross-Sectional Narrowing (CSN) averaged 59 ±13 %.
• Area Stenosis (AS) averaged 47 ± 19 %.
• Regression analysis demonstrated strong correlations between FFR and MLD (r = 0.79, P < 0.0001) as well as between FFR and MLA (r = 0.74, P < 0.0001).
• There were inverse, moderate correlations between FFR and CSN (r = 0.69, P < 0.0001), followed by those between FFR and AS (r = 0.54, P < 0.0001).
• Compared with FFR as the "gold standard," an MLD of 2.8 mm had the highest sensitivity and specificity (93 % and 98 %, respectively) for determining the significance of an LMCS, followed by an MLA of 5.9 mm² (93 % and 95 %, respectively).
• Based on an FFR < 0.75 and an FFR ≥ 0.75, the 38-month survival and event-free survival estimates (EFSEs) were both 100 % and 100 % versus 90 %, respectively (P = NS).

CONCLUSIONS:

The study demonstrates strong correlations between IVUS parameters and FFR results. A decision-making strategy to assess the significance of an LMCS predicated on the use of either a FFR cutoff value of 0.75 or validated IVUS parameters with FFR including the MLD and MLA cutoff values of 2.8 mm and 5.9 mm², respectively, is safe and superior to angiography. Furthermore, among patients with an LMCS, a FFR cutoff value of 0.75 to proceed with medical therapy or revascularization is a strong predictor of survival and event free survival rates.

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