Aim: In patients with end-stage kidney disease (ESKD), it is unclear whether an imbalance between myocardial oxygen supply and demand leads to myocardial injury (MI). This study clarifies the association between the balance of the rate pressure product (RPP), consisting of the systolic blood pressure multiplied by the pulse rate (PR), a marker for myocardial oxygen demand, and hemoglobin (Hb), a marker for oxygen supply, with MI.
Methods: A total of 283 consecutive unselected patients for hemodialysis were enrolled in this retrospective, cross-sectional study, and were divided into four groups according to Hb levels (high or low) and RPP. Potential imbalances between myocardial oxygen supply and demand were defined as patients with simultaneous high RPP and low Hb levels. The odds ratio (OR) for MI, defined as cardiac troponin T (cTnT) of ≥ 0.15 ng/mL was investigated using logistic regression analysis between the four patient groups.
Results: The mean age was 68.7 years, 71.3% were men, and 52.6% had diabetes. The mean Hb level was 9.0 g/dL, and 20.5% of patients were latently diagnosed with MI. The median RPP and cTnT level was 12,144 and 0.083 ng/mL, respectively. When exposed to simultaneous high RPP with low Hb, OR significantly increased compared with that of the well-balanced group (RPP ＜12,500 and Hb ≥ 9.0 g/dL; OR 3.63, p＜0.05). Similar results were obtained in multivariate analysis after adjusting for confounding variables. These associations were enhanced or weakened when the Hb cut-off level became lower (Hb=8 g/dL) or higher (Hb=10 g/dL).
Conclusions: As the myocardial oxygen supply and demand balance in patients with ESKD is potentially associated with MI, appropriate management for blood pressure, PR, and anemia may prevent MI.
Keywords: Cardiac troponin; Hemoglobin; Myocardial ischemia; Rate pressure product.