Post-CABG PCI Tied to Worse Outcomes, Higher Cost

Odds of in-hospital mortality after coronary artery bypass grafting (CABG) about doubled if patients developed acute coronary ischemia requiring percutaneous coronary intervention (PCI) soon after surgery, a study found.

Their 5.1% death rate exceeded the 2.7% of those who didn’t need PCI, a finding that stayed robust despite several statistical adjustments (P<0.001 for all), reported Mohamad Alkhouli, MD, of West Virginia University Heart and Vascular Institute in Morgantown, and colleagues, in the Journal of the American College of Cardiology.

Alkhouli’s group included people recorded in the National Inpatient Sample (NIS) as having received CABG from 2003 to 2014 (n=554,987). Of this cohort, 4.4% got angiography before discharge for a suspected acute coronary ischemia and 2.6% went on to get PCI (the bulk of those within 24 hours of CABG).

“Mirroring the average rate of post-PCI emergency CABG of 3% in the pre-stent era in the early 1990s, this report demonstrates an inversion of the paradigm, where PCI has become the backup procedure of CABG,” commented Paul Guedeney, MD, and Gilles Montalescot, MD, PhD, both of Hôpital La Pitié Salpêtrière in Paris, in an accompanying editorial.

In the study, the strongest predictors of in-hospital PCI after CABG were nonelective admissions (OR 3.45, 95% CI 3.30-3.60) and off-pump CABG (OR 1.85, 95% CI 1.78-1.92). A model that also considered surgical volume showed low-intermediate annual CABG volume as another independent predictor.

Guedeney and Montalescot emphasized this latter finding, writing that low annual CABG volume may be one of the most important factors of standby PCI.

“The relatively high rate of in-hospital post-CABG PCI described in the present study argues in favor of expert heart centers with high volumes of both PCI and CABG to better manage all patients with coronary artery disease,” the pair said.

On top of the difference in mortality, Alkhouli’s group associated PCI after CABG with higher rates of:

• Stroke: 2.1% vs 1.6% (P<0.001)
• Acute kidney injury: 16% vs 12.3% (P<0.001)
• Vascular complications: 6.5% vs 2.3% (P<0.001)
• Acquired pneumonia: 5.5% vs 3.8% (P<0.001)

Moreover, patients also had longer hospitalizations (12 vs 10 days, P<0.001) and pricier hospital bills (average $62,080 vs $44,080, P<0.001), according to the investigators.

“Further studies are needed to assess modifiable risk factors for early coronary compromise following CABG,” they said.

The authors acknowledged the possibility of coding errors in the administrative database that they used, as well as residual confounding in their analyses. They also suggested that the “true incidence of early post-CABG PCI is likely to be higher” due to readmissions within 30 or 60 days after CABG not captured by the NIS.