Stent malapposition, strut coverage and atherothrombotic prolapse after percutaneous coronary interventions in ST-segment elevation myocardial infarction.

Aims: Stent implantation in ST-segment elevation myocardial infarction (STEMI) patients can be challenging and sometimes associated with immediate and long-term suboptimal results. Stent malapposition and strut uncoverage, predictors of stent thrombosis, are frequently detected in STEMI patients at medium/long-term follow-up. Nevertheless, data at a short follow-up are missing. We aimed to assess the extent of stent malapposition and struts coverage in the subacute phase of STEMI after stent implantation in primary or rescue percutaneous coronary intervention (PCI).
Methods: STEMI patients undergone primary or rescue PCI and scheduled for a second coronary angiography after 2-7 days were enrolled. During the second procedure, frequency domain optical coherence tomography (FD-OCT) was performed to assess percentage of malapposed struts (MS%), percentage area of malapposition (MA%), percentage of uncovered struts (US%), percentage area of atherothrombotic prolapse (PA%) and optical coherence tomography thrombus score (OCT-TS).
Results: Twenty patients were included and 21 stents (19 865 struts) were evaluated. Strut uncoverage was relatively limited [US% = 11.1 (8.1-13.6) %]. Stent malapposition was observed frequently, even if at low degree [MS% = 6.4 (3.3-13.3) %, MA% = 1.80 (0.46-2.76) %] as well as atherothrombotic prolapse [PA% = 0.09 (0.00-1.06) %]. Both MA% and PA% were significantly related to residual OCT-TS (R = -0.52, P = 0.02 and R = 0.71, P < 0.001, respectively), use of thrombolysis (P = 0.001 and P = 0.004, respectively) and time elapsed from PCI to FD-OCT analysis (P = 0.001).
Conclusion: In the subacute phase after stenting in STEMI patients, strut uncoverage is relatively limited, while stent malapposition and atherothrombotic prolapse are common albeit limited features. Residual thrombus burden influences the degree of both stent malapposition and atherothrombotic prolapse.