Characteristics, predictors and outcomes after unprotected left main stem primary percutaneous coronary intervention
Authors: Mehmedbegovic Z , Milasinovic D , Jelic D , Zobenica V , Radomirovic M , Vratonjic J , Zaharijev S , Pavlovic A , Vukcevic V , Asanin M , Stankovic G 
Published: November 2020

Abstract

Background
Reports about outcomes of patients undergoing primary percutaneous coronary intervention (PCI) for unprotected left main (ULM) coronary artery are limited. We aimed to investigate the characteristics, in-hospital and the long-term outcomes of these patients.

Methods
From a high-volume, single-centre, prospective registry, in a period from 2009–2019, we identified 111 pts (0.96%) who undergone primary PCI for ULM culprit lesion. The short- and the long-term outcomes in this subset was evaluated and compared to 9463 (82.5%) patients undergoing pPCI for lesions located in other segments (Non-LM group). Technical success was defined as final TIMI 3 flow in both, left main and distal vessels, anterior descending and circumflex artery, without significant residual stenosis (&gt;20% following balloon angioplasty or stent implantation) and side branch compromise (residual stenosis &gt;75%).

Results
Patients with ULM were older and more likely to present as Non-ST-elevation MI (77% vs. 93%; p&lt;0.000) and in cardiogenic shock (40% vs. 2.2%; p&lt;0.000), having less occlusive disease with TIMI 0–1 flow prior to PCI (44% vs. 78%; p&lt;0.000) compared to Non-LM patients. Also, greater procedure complexity was observed with longer lesions &gt;20mm (50% vs. 29%; p&lt;0.000), more intraluminal thrombus (86% vs. 45%; p&lt;0.000), greater number (1,48±0,9 vs. 1,28±0,7; p&lt;0.01) and longer stents (30,5±15,8 vs. 27,4±14,3; p=0.028), more GP IIb/IIIa inhibitors (32% vs. 23%; p=0.022), intra-aortic counterpulsations (7% vs. 0.6%; p&lt;0.000) and contrast media used (202±96 vs. 172±66; p&lt;0.000) in ULM group. Despite obtaining comparable rates of final TIMI 3 flow in main branch (91.9% vs. 95.4%; p=0.084), patients with LMCA had significantly higher in-hospital (27% vs. 4.7%: p&lt;0.000), and one-year all-cause mortality (41% vs. 11%: p&lt;0.000), but for the remaining duration of clinical follow-up (available for 97.8% pts, median duration 51±37 months) survival rates were comparable between ULM and Non-LM pts (18% vs. 15%: p=0.506) (Figure 1).
Regression analysis showed that final TIMI 3 in main branch at 30 days (HR 0.05 [95% CI 0.005–0.604]; p=0.018), while peri-procedural cardiogenic shock (hazard ratio (HR) 8.3 [95% CI 2.5–28.1]; p=0.001), creatinine clearance &lt;60 ml/min (HR 7.5 [95% CI 2.3–25.1]; p=0.001) and technical success (HR 0.16 [95% CI 0.45–0.57]; p=0.005) at 5 years, independently predicted mortality in ULM patients.

Conclusions
Despite performance of primary PCI, patients with MI due to ULM lesions are associated with worse in-hospital and one-year mortality but following that period mortality was comparable to control group. Suboptimal final coronary flow best predicted the 30 day, while peri-procedural cardiogenic shock, renal dysfunction at admission and suboptimal technical procedure result, predicted long-term mortality in these patients.
Figure 1

Funding Acknowledgement
Type of funding source: None