Serum Ionized Calcium as a Prognostic Biomarker in Type B Aortic Dissection After Endovascular Treatment.

OBJECTIVE

Lower serum ionized calcium (iCa) was reported to be associated with a higher risk of adverse events in patients with cardiovascular diseases. This study aimed to investigate the associations between preoperative serum iCa and outcomes of type B aortic dissection (TBAD) patients receiving thoracic endovascular aortic repair (TEVAR).

METHODS

Between January 2016 and December 2019, 491 TBAD patients received TEVAR in a single center. Patients with acute or subacute TBAD were included. Serum iCa (pH 7.4) was obtained from the arterial blood gas analysis before TEVAR. The study population was grouped into the hi-Ca group (1.11 mmol/L ≤ iCa < 1.35 mmol/L) and lo-Ca group (iCa < 1.11 mmol/L). The primary outcomes were all-cause mortality. The secondary outcomes were any major adverse clinical events (MACEs), which included all-cause mortality and aortic-related severe complications. To eliminate bias, 1:1 propensity score matching (PSM) was conducted.

RESULTS

Overall, 396 TBAD patients were included in this study. In the total population, there were 119 (30.1%) patients in the lo-Ca group. After PSM, 77 matched pairs were obtained for further analysis. In the matched population, the 30-day mortality and 30-day MACEs between the two groups presented significant differences (p=0.023 and 0.029, respectively). At 5 years, cumulative incidences of mortality (log-rank p<0.001) and MACEs (log-rank p=0.016) were significantly higher in the lo-Ca group than that of the hi-Ca group. Multivariate cox regression analysis indicated that lower preoperative iCa (hazard ratio for per 0.1 mmol/L decrease, 2.191; 95% confidence interval, 1.487-3.228, p<0.001) was an independent risk factor for 5-year mortality after PSM.

CONCLUSIONS

Lower preoperative serum iCa might have an association with 5-year mortality in TBAD patients after TEVAR. Serum iCa monitoring in this population may facilitate the identification of critical conditions.

CLINICAL IMPACT

Our present study found that the cutoff value of preoperative serum iCa 1.11 mmol/L, which is slightly lower than the lower limit of the normal range of 1.15-1.35 mmol/L, worked relatively well for discerning the high-risk and low-risk TBAD patients at 5 years. Serum iCa monitoring in TBAD patients receiving TEVAR may facilitate the identification of critical conditions.