ADAPT and Overcome – Learning to Stop the Guesswork

By Scott W. Murray, MD

I have been writing for the journal for three years now and the majority of my musings have been based around the fact that using angiography and guesswork in the cath lab may be a recipe for poor(er) practice. I still laugh when I see operators in my own center and those at national and international meetings guessing stent sizes and lengths……”2.5×28 John???…..yeah, that will do!……nominal pressure inflation……It looks good!……Call for the next patient”

In the IVUS or intra-vascular imaging world, we have always struggled to convince the skeptics that seeing the artery from the inside and making measurements to guide interventions, can have a clinical benefit. This is probably due to under-powered, small studies into IVUS use in the 90s and early 2000s and the religious devotion to the angiogram as some form of deity. However, what we did learn from those early studies in the bare-metal stent era can still be applied to this day, in the second-generation DES era:

  1. A small final Minimum Stent Area (<5mm2 )or evidence of stent under-expansion is the largest predictor of stent thrombosis or re-stenosis.
  1. Any evidence of proximal or distal stent edge problems (i.e. dissection) is also important.

Recently, the largest ever study conducted with IVUS guidance has reported its findings. In the ADAPT-DES (Assessment of Dual AntiPlatelet Therapy with Drug-Eluting Stents) trial1, over 8500 real-world patients (no clinical or anatomic exclusions) underwent PCI and received at least one drug-eluting stent. IVUS guidance was prospectively examined with 5200 cases not using IVUS and 3300 cases using IVUS. The results shed new light in favor of IVUS use:

1.         IVUS-Guidance improved clinical outcomes both acute (<30 Days) and at 1 yr.

            • 33% reduction in MI.

            50% reduction in subacute and late stent thrombosis.

These results are despite 40% more IVUS patients initially presenting with STEMI.

2.         IVUS guidance changed the procedure 75% of the time. Longer, more   appropriately sized stents, bigger balloons (pre/post dilatation) were used at higher pressures with no negative impact on outcomes.

Table 1. Basic comparative results from ADAPT-DES Trial presented at TCT 2012.

IVUS group (n=3343)

Non IVUS group (n=5233)

p value

Any ST within 1 year

0.52% 1.04%

0.01

– Acute (< 24 hours)

0.06% 0.04%

0.66

– Subacute (1-30 days)

0.27% 0.56%

0.05

– Late (31 days – 1 year)

0.25% 0.48%

0.1

All-cause death/MI within 1 year

3.96% 5.35%

0.004

Cardiac death within 1 year

0.84% 1.17%

0.1384

Peri-procedural MI

1.26% 1.53%

0.3

Non peri-procedural MI within 1 year

1.23% 2.17%

0.002

___

Overall, In ADAPT-DES, operators who used IVUS pre and post-procedure were found to achieve greater maximal lumen areas for proximal reference lumen area (8.9 vs. 7.6 mm), in-stent lumen area (6.3 vs. 5.8 mm), and distal reference lumen areas (6.5 vs. 6.1, P<.0001 for all measures). Greater maximum lumen area is identified as a key procedural factor to reduce risk for stent thrombosis with DES.

It is clear that IVUS measurement pre-intervention, gives you the comfort to make informed sizing decisions and importantly removes the guesswork!

In addition to these favorable results, a recent large meta-analysis by Zhang et al 2 has shown in 19619 patients from both randomised and observational studies that a mortality benefit exists for IVUS guided stent implantation. It seems that by improving acute stent results we can improve event-free survival compared to angiographic guidance alone.

So, we finally have some data that fulfills the intuitive expectation that measurement, direct visualization and stent “tailoring” wins over angiographic ignorance, blind bravado and guesswork. I think it is time for me to stop ranting on this subject and to leave it up to the individual operators……..What type of stent implanter are you going to be??? 

References

1. Witzenbichler B, Maehara A, Weisz G, et al. TCT-21 Use of IVUS Reduces Stent Thrombosis: Results from the Prospective, multicenter ADAPT-DES Study. J Am Coll Cardiol. 2012; 60(17_S):. doi:10.1016/j.jacc.2012.08.027.

2. Zhang Y, Farooq V, Garcia-Garcia HM, et al. Comparison of intravascular ultrasound versus angiography-guided drug-eluting stent implantation: a meta-analysis of one randomised trial and ten observational studies involving 19,619 patients. EuroIntervention. 2012;8(7):855-865.

Dr Scott Murray is a Specialist Registrar in Cardiology and a Clinical Research Fellow at Liverpool Heart and Chest Hospital, U.K

Additional articles by Scott Murray:

iFR: Will We Ever “Wave” Goodbye to Adenosine in the Cath Lab?

OCT: Seeing the Artery in a New Light

With FREEDOM Comes Responsibility

When is a “Good Result” Just Not Good Enough?

“No Noble Thing can be Done Without Risk” — Exploring the Dark Side of PCI

Do We Have the COURAGE to Stop Using Percentage Stenosis?

PROSPECT and the Gumpian Theory of Atherosclerosis

Desperate Times, Desperate Measures: The ZEN Trial — Will it Ultimately Flop?

Vascular Calcification: Friend or Foe?

We Will Never Truly EXCEL Until We IVUS

Pondering on Paradigms From Across the Pond

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One Response to ADAPT and Overcome – Learning to Stop the Guesswork

  1. Stephen Pettit says:

    Good effort Scott – not convinced about the causal relationship between IVUS and clinical outcomes. This was an observational study – association yes, cause-effect who knows? Randomise…

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