Lower Extremity Arterial Calcification on Preoperative Knee Radiographs as a Predictor of Postoperative Cardiovascular Events After Primary Total Knee Arthroplasty

Background

A cross-sectional study of total knee arthroplasty (TKA) patients was conducted to determine the association of lower-extremity arterial calcification (LEAC) with acute perioperative cardiovascular events (CVEs).

Methods

Regression modeling was used to examine the association of radiographic presence of LEAC and acute myocardial infarction (MI), perioperative CVE, 30-day CVE readmit, and 30-day and 1-year mortality.

Results

Of 900 TKA patients, LEAC was identified in 21.1%. Of LEAC cases, 1.6% had an acute MI vs 0.1% of non-LEAC cases (P = .031). Perioperative CVE rate was 5.8% for LEAC vs 1.5% for non-LEAC (P = .002). Having LEAC was identified as a significant risk factor for a perioperative CVE (odds ratio [OR] 2.83; 95% confidence interval [CI] 1.09-7.35). Because of limited number of acute MI events, absence of 30-day CVE readmit, 30-day mortality, and few 1-year mortality events, computing OR for these was not possible. Likewise, because of small number of events (n = 3), estimates for the odds of LEAC cases having an acute MI are less reliable, yielding extremely large random errors (OR 11.37; 95% CI 0.09-597.93) and must be interpreted with caution. The OR for 1-year mortality was 1.88 (95% CI 0.17-13.20), but again with large random errors.

Conclusion

Our study shows that LEAC around the knee is associated with an increased risk of having a perioperative CVE. Crude radiographic detection of LEAC around the knee has the potential to improve risk stratification for TKA patients by informing the surgeon of the need for further preoperative cardiac workup.