Tandem lesion

Assessment of tandem lesions by FFR

What is a tandem lesion?

Multiple stenoses in series along one coronary artery defined by lesions requiring ≥ 2 DES, which may be interspersed by a normal looking area of 10-20 mm.

Why physiological assessment in Tandem lesions?

Physiological lesion length is significantly shorter than anatomical length and the total stent length deployed¹. More stent length is associated with more events.

How one lesion affects the FFR measurement of tandem lesion²?

If we place the wire between the lesions – ie at P2 , The presence of the distal stenosis means the increase in flow caused by the hyperaemic agent is not transmitted uniformly though the vessel; So the measured pressure distal to the proximal stenosis may be higher than may actually be the case, causing the severity of the proximal stenosis to be underestimated. This is illustrated in Figure 1

What is the solution? -- “The Big Delta rule”

One solution is to do an FFR pullback and see the lesion with the largest pressure drop or the “Big Delta”. We will illustrate this in this case.

Case: 57 years male, CSA FC II , Good LV function, Smoker. CAG – Single vessel disease, Tandem lesions in LAD.

Figure 1: LCA angiogram showing tandem lesions.

STEPS IN DOING PCI IN THIS CASE

Step 1. Assess the significance of the whole vessel (LAD). It was 0.71, ( ≤0.80), so the revascularization of LAD is justified regardless of true FFR of individual lesions.

Step 2. Pull back from distal LAD on IV adenosine and see the lesion with big Delta. (Fig. 2)

Step 3. Stent the lesion with big delta³.

Step 4. Reassess the second lesion again with FFR pullback.

Step 5. If FFR across lesion 2 is <0.80, Stent the second lesion also.

Step 6. If FFR across lesion 2 is >0.80, defer stenting to the lesion.

Figure 2: Step 1 and 2 - FFR pullback. Distally in LAD – FFR 0.71, Big delta at the proximal lesion.

Figure 3: Step 3 : Stenting the lesion with Big Delta (0.73 to 0.91) (here the proximal lesion)

Figure 4: Step 4 ; FFR of the second lesion - - 0.72 in this case.

Figure 5: Step 5 – Post stent of the second lesion. (Post - stenting of both lesions FFR 0.95).

Take home points.

• Tandem or serial lesion assessment can be assessed by FFR pullback by the “big delta rule”, it can lead to reduction in the number of stents.
• Step1 : The rule of big delta

Stenosis A > B → Fix stenosis A

Stenosis A < B → Fix stenosis B

Stenosis A = Stenosis B → Fix proximal stenosis

• Step2 : Re-evaluate PG after fixing the first stenosis

If FFRmyo <0.80 Fix another stenosis

If FFRmyo >=0.80 leave the stenosis without stenting.

References

1. Nijjer SS, Sen S et al. , Pre-angioplasty IFR pullback provides virtual intervention and predicts hemodynamic outcome for serial lesions and diffuse coronary artery disease. JACC Cardiovasc Interv. 2014 Dec;7(12):1386–96.
2. Nijjer SS, Sen S et al. The iFR pullback: a novel innovation using baseline physiology to optimise coronary angioplasty in tandem lesions. Cardiovasc Revasc Med. 2015 Apr 1;16(3):167–71.
3. Kim H-L, Koo B-K, Nam C-W et al. Clinical and physiological outcomes of FFR -guided PCI in patients with serial stenoses within one coronary artery. JACC Cardiovasc Interv. 2012 Oct;5(10):1013–8.