By: Faisal Latif, MD, FSCAI and Suresh Mulukutla, MD, FSCAI

         P atient (age, BMI, acuity of presentation, LVEF)
         C ABG candidate?
         I nformed consent

othe R  co-morbidities
         I nteraction with patient (shared decision making)
         S cores (SYNTAX, CathPCI, NERS)
         K idney function (Creatinine clearance)

In this era, when an increasing number of patients with coronary artery disease (CAD) are presenting at a later age and with several co-morbidities, interventional cardiologists frequently encounter patients requiring high-risk PCI, as many such patients are not surgical candidates. Although these cases are challenging, they also are an opportunity to provide the benefits of revascularization to these patients percutaneously. Depending on the clinical setting, PCI can provide not only symptomatic relief but also improved quality of life. The major challenge remains a thorough assessment of the risk-to-benefit ratio and a detailed discussion with the patient and his or her family to achieve shared decision making and clarify expected outcomes, as an extension of informed consent.

While various risk scores, such as STS and Euroscore, have been used for many years to estimate peri-operative risk of complications from CABG, the risk scores to estimate peri-procedural complications for PCI have not been as widely used. The latest ACC/AHA/SCAI guidelines for PCI recommend using these scores.¹ An excellent tool is the NCDR CathPCI Registry risk score developed from data on more than a million patients with almost 20% of patients presenting with STEMI.²

This year SCAI released the "SCAI PCI Risk Calculator" app, which utilizes the BMC2 calculator to compute the risk of in-hospital mortality, transfusion and contrast-induced nephropathy (CIN). Another tool developed by SCAI uses the NCDR, MassDAC and DELTA models to predict the risks of in-hospital mortality, femoral vascular injury, bleeding, dialysis, CIN, one-year target vessel revascularization (TVR) and 30-day readmission. An upcoming version of the SCAI tool will also provide a table of the comparative one-year TVR rates between bare metal stents and drug-eluting stents for any combination of minimum stent size and total stent length for anywhere between one and three lesions treated (based on the same patient clinical presentation) to help facilitate discussions about restenosis benefits vs. bleeding risks. Below is a snapshot of the risk percentage of a number of important variables obtained as a final result after using the SCAI PCI Risk Calculator for a hypothetical patient.

While CABG risk is more dependent on clinical variables, during high-risk PCI the anatomical complexity of CAD also plays an important role in peri-procedural outcomes. Various retrospective analyses have shown that age, renal function and left ventricular ejection fraction are the most important clinical variables, while anatomical complexity can be gauged well from the SYNTAX score.³ Based on these findings, various risk calculators have been developed and compared retrospectively.³    

Although there is no consensus yet, PCI risk calculation can also be performed using clinical SYNTAX score (CSS) or the New Risk Stratification score (NERS), which incorporate the complexity of coronary anatomy and have been shown to be more predictive of peri-procedural adverse events, including death and ischemic endpoint, when compared to purely clinical risk scores in post-hoc analyses.³ Requiring 54 variables, calculation of NERS score is more cumbersome, yet it is a good predictor of major adverse cardiac events (MACE). NERS score includes clinical as well as procedural variables, such as bifurcation stenting.³ CSS is easier to calculate using this simple formula:

CSS = [SYNTAX score] x [modified ACEF score]

Modified ACEF Score = age/LVEF + 1 point for each 10 ml/min reduction in Creatinine Clearance below 60 ml/min per 1.73 m²

In summary, using risk scores provides a solidified basis for the cardiologist to discuss risks of PCI, particularly for high-risk procedures.

» View PCI Risk Assessment Tools

References

1. Levine GN, Bates ER, Blankenship JC, et al. 2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions. Circulation. 2011;124:e574–e651.

2. Brennan JM, Curtis JP, Dai D, et al. Enhanced mortality risk prediction with a focus on high-risk percutaneous coronary intervention: results from 1,208,137 procedures in the NCDR (National Cardiovascular Data Registry). JACC Cardiovasc Interv. 2013;6(8):790-9.

3. Chen SL, Chen JP, Mintz G, et al. Comparison between the NERS (New Risk Stratification) score and the SYNTAX (Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery) score in outcome prediction for unprotected left main stenting. JACC Cardiovasc Interv. 2010;3(6):632-41.