Impact of Arterial Calcification on Cardiovascular and Renal Outcomes in Kidney Transplant Patients

Abstract

<b><i>Introduction:</i></b> Coronary artery calcification score (CACS) and abdominal aortic calcification score (AACS) are both well-established markers of vascular stiffness, and previous studies have shown that a higher CACS is a risk factor for chronic kidney disease (CKD) progression. However, the impact of pretransplant CACS and AACS on cardiovascular and renal outcomes in kidney transplant patients has not been established. <b><i>Methods:</i></b> We included 944 kidney transplant recipients from the KoreaN cohort study for Outcome in patients With Kidney Transplantation (KNOW-KT) cohort and categorized them into three groups (low, medium, and high) according to baseline CACS (0, 0 &lt; and ≤100, &gt;100) and AACS (0, 1–4, &gt;4). The low (0), medium (0 &lt; and ≤ 100), and high (&gt;100) CACS groups each consisted of 462, 213, and 225 patients, respectively. Similarly, the low (0), medium (1–4), and high (&gt;4) AACS groups included 638, 159, and 147 patients, respectively. The primary outcome was the occurrence of cardiovascular events. The secondary outcomes were all-cause mortality and composite kidney outcomes, which comprised of &gt;50% decline in the estimated glomerular filtration rate and graft loss. Cox regression analysis was used to investigate the association between baseline CACS/AACS and outcomes. <b><i>Results:</i></b> The high CACS group (<i>N</i> = 462) faced a significantly higher risk for cardiovascular outcomes (adjusted hazard ratio [aHR], 5.97; 95% confidence interval [CI], 2.01–17.7) and all-cause mortality (aHR, 2.74; 95% CI, 1.27–5.92) compared to the low CACS group (<i>N</i> = 225). Similarly, the high AACS group (<i>N</i> = 638) had an elevated risk for cardiovascular outcomes (aHR, 2.38; 95% CI, 1.16–4.88). Furthermore, the addition of CACS to prediction models improved prediction indices for cardiovascular outcomes. However, the risk of renal outcomes did not differ among CACS or AACS groups. <b><i>Conclusion:</i></b> Pretransplant arterial calcification, characterized by high CACS or AACS, is an independent risk factor for cardiovascular outcomes and mortality in kidney transplant patients.