skip to main content

Tandem Lesion Physiological Assessment — EECC MCQ

Instant feedback + full explanation. One question, done properly.

HardCoronary Artery DiseaseTandem Lesion Physiological AssessmentEECC

A 70-year-old man with CCS and a 50% left main stenosis on CTCA is referred for invasive assessment. iFR of the LMS is 0.92. However, there is also a sequential 60% mid-LAD stenosis. How does tandem (serial) disease affect physiological assessment?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — Serial stenoses create haemodynamic interdependence — each lesion underestimates the other's severity because the distal stenosis reduces flow across the proximal one and vice versa; pull-back pressure assessment or individual lesion assessment after treating one lesion is recommended

When two or more stenoses exist in series (tandem lesions), they create haemodynamic interdependence: each lesion reduces maximal flow through the other, causing mutual underestimation of individual severity. The measured FFR/iFR of the proximal lesion is artifactually elevated because reduced flow from the distal lesion decreases the pressure gradient across it (and vice versa). Approaches to serial lesions: (1) FFR/iFR pullback — measuring the pressure gradient at each lesion by pulling back the wire (identifies the lesion contributing most to the overall gradient); (2) treat the most severe lesion first, then reassess the remaining lesion; (3) computational approaches (predicted individual FFR). The 2024 ESC CCS Guidelines acknowledge the limitations of FFR/iFR in tandem disease and recommend careful interpretation with pullback assessment.

Reference: ESC (2024): CCS Guidelines