#2567 ASSOCIATION OF IMBALANCE OF MYOCARDIAL OXYGEN SUPPLY/DEMAND WITH MYOCARDIAL INJURY IN END STAGE KIDNEY DISEASE PATIENTS
Authors: Nakata Kenji , Harada Minako , Hitaka Mai , Tanaka Yuri , Joki Nobuhiko 
Published: June 2023

Abstract

Background and Aims
It is well known that oxygen transport ability is impaired in patients with anemia, low hemoglobin (Hb) level, whereas the double product (DP, bpm*mmHg), consisting of the systolic blood pressure (SBP) multiplied by the heart rate (HR), is an index of myocardial oxygen consumption. The combination of these two markers could be a potential marker for balance of myocardial oxygen supply and demand. Therefore, we hypothesized that the balance of these two markers may lead to myocardial damage in end-stage kidney disease (ESKD) patients who is susceptible to vulnerable heart in oxygen balance. The purpose of this study is to examine the association of balance of DP and Hb with myocardial injury in ESKD patients.

Method
A single-center, cross-sectional study has conducted. From December 2010 to November 2021, 327 consecutive ESKD patients started maintenance hemodialysis (HD). Among them, 44 patients met the exclusion criteria as follows: (1) missing data of cardiac troponin T (cTnT); (2) complicating acute cardiac syndrome; (3) death during hospitalization for HD initiation, a total of 283 ESKD patients were enrolled into the study finally. The patients were divided four groups according to the high or low of Hb level of 9 g/dL and DP 12500, a median of our patients, and named low-DP/high-Hb; G1, low-DP/low-Hb; G2, high-DP/high-Hb; G3, and high-DP/low-Hb; G4. The patients with G1 group were defined as a well oxygen balanced group, whereas those with G4 was defined as an imbalance of oxygen supply and demand group. Based on the results of previous study, cTnT cut off for myocardial injury was serum cTnT ≧0.15 ng/mL. Odds ratio (OR) for myocardial injury was calculated in each group compared with well oxygen balanced group by logistic regression analysis.

Results
Median age was 72 years, 71% of them were male, 52.6% had diabetes. Mean Hb level was 9.09 ± 1.61, and median DP was 12144 (25% tile 10540, 75% tile 14688). Median cTnT was 0.083 (25% tile 0.057 and 75% tile 0.13), and 20.4% of patients were defined as suffering from myocardial injury latently. In the adjusted model, the odds for myocardial injury was significantly increasing in high-DP compared with low-DP (OR: 1.87, p = 0.049), while low-Hb did not show significant increment of odds for myocardial injury compared with high-Hb. As shown in the Table 1, compared to well-balanced group (G1), OR increased by exposing only high-DP (G3), however it was not statistically significant (OR 1.20, p = 0.68). Interestingly, by exposing with high-DP with low-Hb simultaneously (G4), synergistic increased OR was found compared with well-balanced (G1) group (OR 3.07, 95%CI 1.24-7.62, p = 0.015). Furthermore, these associations were enhanced and weakened if Hb cut-off level became to be lower (Hb 8 g/dL) and higher (Hb 10 g/dL), as shown in Tables 2, 3.

Conclusion
Imbalance of oxygen supply (Hb) and demand (DP) was associated with myocardial injury in incident HD patients. Appropriate control of anemia, SBP and HR may have possibility to prevent myocardial injury. Especially we need to pay attention more to the Hb level if BP and HR control is insufficient. Tables 1, 2, 3. Odds ratio for cTnT≧0.15 in four groups divided by DP and Hb (adjusted for age, male, CRP, albumin, diabetes mellitus).