Randomized study to assess the effect of thrombus aspiration on flow area in patients with ST-elevation myocardial infarction: an optical frequency domain imaging study—TROFI trial
Selected in European Heart by G.G. Toth
Yoshinobu Onuma, Leif Thuesen, Robert-Jan van Geuns, Martin van der Ent, Steffen Desch, Jean Fajadet, Evald Christiansen, Peter Smits, Niels Ramsing Holm, Evelyn Regar, Nicolas van Mieghem, Vladimir Borovicanin, Dragica Paunovic, Kazuhisa Senshu, Gerrit-Anne van Es, Takashi Muramatsu, Il-Soo Lee, Gerhard Schuler, Felix Zijlstra, Hector M. Garcia-Garcia, Patrick W. Serruys on behalf of the TROFI Investigators
Eur Heart J (2013) 34 (14): 1050-1060.
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Primary PCI (pPCI) as the treatment of acute ST-elevation myocardial infarction has been already well established by previous studies. The beneficial effects of additional thrombus aspiration (TB) in terms of angiographic result (TIMI flow, blush score, etc.), and in terms of clinical outcome (reduction of cardiac death and repeat revascularization) have been also shown recently.
This work aims to analyze the background of the above described findings, by investigating intraluminal changes during pPCI with or without thrombus aspiration (TB).
- Study enrolled 141 patients with STEMI (<12hrs), who were randomized to pPCI with TB versus pPCI without TB (1:1).
- Optical Frequency Domain Imaging (OFDI) was performed after PCI. Operator was blinded to the results of OFDI, therefore all decisions about result-optimalisation had to be made by angiographic evaluation only.
- Angiographic and OFDI images were analysed by a corelab, blinded to the randomisation arm. Primary endpoint was the minimum flow area (MinFA), defined as:
[stent area + incomplete apposition]-[tissue protrusion + isolated intraluminal defect area]
- There was no significant difference in MinFA between the with TB versus the without TB groups (7.08 ± 2.14 vs 6.51 ± 1.99; p=0.12)
- There was no significant difference in the rate of final TIMI 0 / I / II / III flow between the with TB versus the without TB groups (0.0 / 3.1 / 4.6 / 92.3 vs 0.0 / 6.0 / 7.5 / 86.6%; p=0.63)
- There was no significant difference in the rate of final Blush grade 0 or 1 / 2 / 3 between the with TB versus the without TB groups (15.5 / 49.3 / 35.2 vs 11.6 / 47.8 / 40.6%; p=0.64)
- In this study the investigators performed a precise analysis for better understanding the intraluminal changes during pPCI and the potential beneficial effects of TB. The investigation focused mainly on morphological changes, which were evaluated by OFDI.
- The study failed to reach the primary endpoint, meaning that there was no significant difference in any of the examined morphological metrics between the with TB versus the without TB groups.
- One of the most important limitations, as declared also by the authors, is that this study is a pure mechanistic analysis without considering potential physiological consequences of distal embolisation. The other is, as also mentioned by the authors, that the population was rather a low-risk subgroup of STEMIs. Considering the relatively high rate of baseline TIMI II or III flow (more than 50% of all cases), it must have been the case, indeed.
- The fact, that this study failed to show any difference in the examined ‘morphologic metrics’, pronounces that the cornerstone of clinical benefit (shown by other studies) should originate rather from physiological consequences on the level of the microcirculatory compartment. Therefore physiologic evaluation of the success or the failure of our treatment might be of more scientific but even clinical interest.