Editorial Comment

Direct Stenting for STEMI: Doesit really make a difference?

Arnold Seto,* MD, and Morton Kern, MD

Department of Medicine, Division of Cardiology,Long Beach Veterans Affairs Medical Center, LongBeach, California

ST-elevation myocardial infarctions (MIs) are char-acterized by thrombotic occlusions precipitated by pla-que rupture. The composition of aspirated thrombiincludes a metabolically toxic brew of activated plate-lets, necrotic cells, lipid, and fibrin. Distal emboliza-tion of such material during percutaneous coronaryintervention (PCI) is a major contributor to microvas-cular injury, resulting in persistent ST-segmentchanges, larger infarct size, hemodynamic instability,and death.

Direct stenting (DS) without balloon predilatation

may reduce vessel wall damage and distal emboliza-

tion, potentially reducing the incidence of no-reflow,

MI, and death. However, there are significant down-

sides to DS including: underestimation of true vessel

size, failure to cross, nondilatable lesions, inadequate

stent expansion, geographic miss, late stent malapposi-

tion, and restenosis. As a result, in practice DS has

been reserved for simple lesions without angulation,

calcification, or tortuosity.Studies of DS for both stable angina and ST-

elevation MI have had mixed results. A meta-analysisof 24 randomized controlled trials of DS versus con-ventional stenting (CS) in PCI found that DS was asso-ciated with reduction in MI [odds ratio (OR) of 0.77;95% CI 0.55–0.99, P¼ 0.04], driven by a reduction inperiprocedural MI [1]. However, only three smallrandomized trials of DS in ST-segment elevation MIhave been conducted, with conflicting results. Ozdemiret al. [2] found a benefit to DS in corrected TIMIframe count (cTFC) and TIMI 3 flow rates in a smalltrial of 50 patients. Loubeyre et al. [3] in 206 patientsfound no difference in cTFC or TIMI flow, but a bene-fit in ST-segment resolution (no ST-segment resolutionin 20.2% versus 38.1% in DS versus CS, P¼ 0.01) anda composite endpoint of no- or slow-reflow, electrocar-diographic changes, and clinical outcome (11.7% vs.26.9%, P¼ 0.01). In contrast, Gasior et al. [4] found in

217 patients no difference in TIMI flow, perfusionscore, ST-segment resolution, or 5 year clinical out-come, but a higher risk of restenosis (30% vs. 16%,P¼ 0.024) with DS.

It is with this background that Dziewierz et al. [5]examine the impact of DS on the outcome of ST-segment MI patients from their EUROTRANSFERregistry. From a population of 1,419 patients, DS wasused in 276 (19.5%) of patients and was associatedwith greater rates of TIMI 3 flow (94.9% vs. 91.5%),lower rates of no-reflow (1.4% vs. 3.4%), higher ratesof ST-segment resolution (86.2% vs. 76.3%), and areduction in 1-year mortality (adjusted OR 0.45 (0.21–0.99), P¼ 0.047). Their retrospective, nonrandomizedanalysis suggests that DS in primary PCI was associ-ated with improved angiographic results and long-termsurvival.

While a positive result, determining causation froman association is difficult from a retrospective study,particularly of an operator-selected technique. In thisstudy, patients who received DS were significantlyyounger, more likely to have TIMI 2 or 3 flow at base-line (44% vs. 26%), and more likely to have receivedaspiration thrombectomy (26% vs. 8%) and preloadedclopidogrel (42% vs. 31%). They were less likely tohave an left anterior descending infarct or multivesseldisease. Any of these factors might have had a greaterimpact on outcome than accounted for in the authors’statistical model. Propensity score adjustment typicallydoes not sufficiently account for the impact of meas-ured factors, compared with the more robust propensitymatching approach. Propensity matching would haveexcluded much of the cohort because of the significantbaseline differences between the two groups. Finally,unmeasured confounders in the form of operator,patient, and lesion characteristics almost certainly influ-enced the operators’ choice to use DS rather than CS.

Conflict of interest: Nothing to report.

*Correspondence to: Arnold Seto, MD; Long Beach Veterans

Affairs Medical Center, 5901 East 7th Street, 111C, Long Beach,

CA 90822. E-mail: Aseto@uci.edu

Received 22 September 2014;

DOI: 10.1002/ccd.25681

Published online 29 October 2014 in Wiley Online Library

(wileyonlinelibrary.com)

VC 2014 Wiley Periodicals, Inc.

Catheterization and Cardiovascular Interventions 84:932–933 (2014)

What then, does the work by Dziewierz et al. tell usfor clinical practice? At most, one can take away thatexperienced operators are able to identify lesions atlow risk and choose a simplified PCI approach. Theirlarge estimated mortality reduction is of borderline sta-tistical significance and unreliable. Nevertheless, DSmay be a reasonable option in selected patients under-going primary PCI, with the emphasis on selection:arteries that are tortuous, angulated, calcified, or totallyoccluded are poor candidates for DS and require lesionpreparation.

DS is only one option to reduce distal embolizationand no-reflow, and may have more risks than the alter-natives. Thrombus removal in the form of aspiration orrheolytic thrombectomy prior to stent placement maybe safer and more effective. A pharmacoinvasive strat-egy of gentle balloon angioplasty with glycoproteininhibitors and deferred stent implantation (DEFER–STEMI) also holds promise, particularly for vesselswith a large thrombus burden. Newer technologies mayallow the operator to trap thrombotic material behindthe stent struts (MGuard, InspireMD, Tel Aviv, Israel)or use a self-expanding stent (Stentys, Paris, France) tomaintain stent apposition as the thrombus is slowlyresorbed. With such promising strategies on the

horizon, DS may be obsolete before it is ever provento be effective.

REFERENCES

1. Piscione F, Piccolo R, Cassese S, Galasso G, D’Andrea C, De

Rosa R, Chiariello M. Is direct stenting superior to stenting with

predilation in patients treated with percutaneous coronary inter-

vention? Results from a meta-analysis of 24 randomised con-

trolled trials. Heart 2010;96:588–594.

2. Ozdemir R, Sezgin AT, Barutcu I, Topal E, Gullu H, Acikgoz N.

Comparison of direct stenting versus conventional stent implanta-

tion on blood flow in patients with ST-segment elevation myocar-

dial infarction. Angiology 2006;57:453–458.

3. Loubeyre C, Morice MC, Lefevre T, Pi�echaud JF, Louvard Y,

Dumas P. A randomized comparison of direct stenting with con-

ventional stent implantation in selected patients with acute myo-

cardial infarction. J Am Coll Cardiol 2002;39:15–21.

4. Gasior M, Gierlotka M, Lekston A, Wilczek K, Zebik T,

Hawranek M, Wojnar R, Szkodzinski J, Piegza J, Dyrbus K,

Kalarus Z, Zembala M, Polonski L. Comparison of outcomes of

direct stenting versus stenting after balloon predilation in patients

with acute myocardial infarction (DIRAMI). Am J Cardiol 2007;

100:798–805.

5. Dziewierz A, Siudak Z, Rakowski T, Kleczy�nski P, Zasada W,

Dubiel JS, Dudek D. Impact of direct stenting on outcome of

patients with ST-elevation myocardial infarction transferred for pri-

mary percutaneous coronary intervention (from the EUROTRANS-

FER registry). Catheter Cardiovasc Interv 2014;84:925–931.

Direct Stenting for STEMI 933

Catheterization and Cardiovascular Interventions DOI 10.1002/ccd.Published on behalf of The Society for Cardiovascular Angiography and Interventions (SCAI).