Are higher operator volumes for unprotected left main stem percutaneous coronary intervention associated with improved patient outcomes?

Selected in Circulation: Cardiovascular Interventions by D. Milasinovic

The presented results appear to further strengthen the notion that operator’s experience may be an important effect modifier in LM PCI.

References

Authors

Kinnaird T, Gallagher S , Anderson R, Sharp A, Farooq V, Ludman P, Copt S, Nick Curzen N, Banning A, Mamas M.

Reference

Circ Cardiovasc Interv. 2020;13:e008782

Published

June 2020

Link

Read the abstract

Reviewer

Dejan Milasinovic

@MilasinD18

Interventional cardiologist / Cardiologist

Belgrade, Serbia

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My Comment

Why this study? – the rationale/objective

The aim of this study was to assess the impact of operator volumes on clinical outcomes following unprotected left main (LM) percutaneous coronary intervention (PCI).

How was it executed? – the methodology

6724 unprotected LM PCI were analyzed from the British Cardiovascular Intervention Society (BCIS) National Database from the period 2012-2014 for which the number of procedures per operator was available.
Operators were divided into 4 quartiles (Q) according to the annualized LM PCI rate, with a median number of LM PCI procedures per year 2 (Q1), 5 (Q2), 10 (Q3) and 21 (Q4).
Study endpoints included procedural complications, in-hospital MACCE and bleeding, as well as 30-day and 12-month mortality.

What is the main result?

In the wider period from 2007 to 2014, the rate of LM PCI in the BCIS database rose from 2 to 4.1% of the total PCI performed.
The crude rate of in-hospital MACCE was reduced with rising operator volumes (6.5% in Q1 vs. 5.4% in Q2 vs. 4.2% in Q3 vs. 2.7% in Q4) and emergency cardiac surgery was required only in lower-volume operator groups (Q1 and Q2), whereas there was no difference in bleeding.
12-month mortality also reflected the difference in the annual number of procedures per operator, with the lowest mortality rate in the group of operators with a median procedural volume of 21 LM PCI per year (15.9% in Q1 vs. 15.6% in Q2 vs. 15.8% in Q3 vs. 8.7% in Q4).
The results remained consistent after adjusting for baseline differences among the groups. A minimum number of LM PCI per year associated with improved survival was 16.

Critical reading and the relevance for clinical practice

The here presented results appear to further strengthen the notion that operator’s experience may be an important effect modifier in LM PCI (the current ESC guidelines recommend that LM PCI is performed by operators with at least 25 of such procedures per year, based on an observational study including 1948 patients with LM PCI between 2004 and 2011).

Notwithstanding the lack of information regarding procedural details (such as the stenting strategy and the applied optimization techniques) and the inherent limitations of an observational study design, the presented analysis seems to provide at least two important practical messages. First, more than half of the overall number of LM PCI, and in the lowest-volume group, two-thirds (67%), were performed in patients presenting with an acute coronary syndrome (ACS). This may highlight the need both for a broader education in planning and performing LM PCI and for the organisation of regional services with the potential for a swift transfer of stabilized ACS patients (mainly NSTE-ACS) among centers of varying levels of procedural expertise. Second, the fact that rotational atherectomy was used in one-fifth (22%) of cases treated by the highest-volume operators, may emphasize the importance of adequate lesion preparation for the overall success of left main stenting.

In summary, amid the ongoing efforts to improve outcomes of LM PCI, which have so far included a standardised approach to intracoronary imaging guidance and testing of different strategies for LM bifurcation stenting, the here presented study appears to highlight the importance of operator’s experience, as our community moves forward with perhaps a more liberal selection of patients that may undergo percutaneous treatment of left main disease.