SOLACI | Latin American Society of Interventional Cardiology

Courtesy of Dr. Agustín Vecchia.

The link between operator volume and clinical outcomes has been long and widely debated. After years of discussion, there are promoters and detractors. Currently, interventional cardiology societies all over the world classify centers as “high-volume” or “low-volume” using arbitrary parameters, and require training fellows to perform an also arbitrary number of procedures considered as “enough” training.

The study discussed below is one of the few published works to date showing that operator volume and experience have an impact on long-term outcomes of patients who underwent an angioplasty.

The study included 1948 consecutive patients who underwent unprotected left main angioplasty performed by 25 different operators at a single center (Fu Wai Hospital, Beijing, China) from January 2004 to December 2011. High-volume experienced operator was defined as a physician who performed at least 15 left main angioplasties annually for the last 3 consecutive years. Physicians who did not meet such a requirement were deemed “less” experienced.

Of all operators (n = 25), 7 (28%) were considered as experienced and 18 (72%) were considered as “less” experienced. Experienced operators performed most left main angioplasties: they operated on 1422 patients (73%), while less experienced operators treated 526 patients (27%).

The mean number of procedures was 25 ± 8 angioplasties for the experienced operator group and 4 ± 3 angioplasties for the other group. Patients treated by experienced operators had more complex and extensive coronary disease, and received first-generation drug-eluting stents (DES) more frequently; intravascular ultrasound (IVUS) guided decision-making in most cases (39.2% vs. 31.7%; p = 0.002).

At 30 days:

Mortality in the group of patients treated by experienced operators was 0.6% vs. 2.0% in the group treated by less experienced operators (p = 0.008).

Rates of infarction, stroke, revascularization, and stent thrombosis were nominally lower in the group of patients treated by experienced operators, although the difference was not statistically significant.

Being treated by an experienced operator decreased the adjusted risk of cardiovascular mortality (hazard ratio [HR]: 0.22; 95% confidence interval [CI]: 0.09 to 0.59; p = 0.003) and the overall mortality rate (adjusted HR: 0.30; 95% IC: 0.12 to 0.73; p = 0,008).

The stent thrombosis rate tended to be lower in the group of patients treated by experienced operators (HR: 0.34; 95% IC: 0.11 to 1.06; p = 0.06).

At 3 years:

The cardiovascular mortality rate was lower in the group of patients treated by experienced operators: 2.5% vs. 4.6%, p = 0.02.

The overall mortality rate tended to be lower in patients treated by experienced operators: 3.8% vs. 5.3%, p = 0.15.

No significant differences were observed in rates of infarction, stent thrombosis, or revascularization.

After adjustment for cardiovascular risk factors using Cox proportional hazards models, being treated by an experienced operator reduced cardiovascular mortality by almost half (HR: 0.49; 95% IC: 0.29 to 0.84; p = 0,009).

The subgroup analysis did not find significant differences when comparing the use of one or two stents (p = 0.39), distal left main coronary artery (LMCA) involvement (p = 0.93), or the use of IVUS (p = 0.47). Adding operator experience to validated risk scores such as the SYNTAX (Synergy Between PCI With Taxus and Cardiac Surgery) and SYNTAX II scores improved their discrimination capability.

Editorial

This study is the largest body of evidence published to date regarding the positive impact of operator experience on short- and long-term outcomes of left main angioplasty. Conclusions seem to be logical, particularly when taking into account that physicians in the “experienced” group performed 6 times more procedures than those in the “less experienced” group (mean: 25 vs. 4).

This is the first time a study suggests that operator experience can be considered a determinant variable for long-term patient outcome. Incorporating this variable to outcome analysis in all special rooms for hemodynamic procedures seems to be a reasonable conclusion. Nowadays, left main lesions are increasingly treated with angioplasty. In consequence, it may be time to consider how progress along the learning curve impacts patients.