Factors associated with subendocardial ischemia risk in patients on hemodialysis

Abstract Introduction: Bone metabolism disorder (BMD) and vascular dysfunction contribute to excess cardiovascular mortality observed in hemodialysis patients. Vascular dysfunction, a new marker of atherosclerosis, can play a role in this risk. Even though associated with higher mortality in the general population, such vascular evaluation in patients on hemodialysis has not been extensively studied. Methods: In this cross-sectional study, hemodialysis patients were submitted to flow-mediated dilation, subendocardial viability ratio (SEVR) and ejection duration index assessment, in order to estimate the impact of BMD markers on vascular dysfunction. Results: A matched cohort of patients with (n = 16) and without (n = 11) severe secondary hyperparathyroidism (SHPT) was studied. Additionally, time spent under severe SHPT was also evaluated. Patients with severe SHPT had lower SEVR and higher ejection duration index, indicating higher cardiovascular risk. Lower SEVR was also associated to diastolic blood pressure (r = 0.435, p = 0.049), serum 25-Vitamin-D levels (r = 0.479, p = 0.028) and to more time spent under severe secondary hyperparathyroidism (SHPT), defined as time from PTH > 500pg/ml until parathyroidectomy surgery or end of the study (r = -0.642, p = 0.027). In stepwise multiple regression analysis between SEVR and independent variables, lower SEVR was independently associated to lower serum 25-Vitamin-D levels (p = 0.005), female sex (p = 0.012) and more time spent under severe SHPT (p = 0.001) in a model adjusted for age, serum cholesterol, and blood pressure (adjusted r² = 0.545, p = 0.001). Conclusion: Subendocardial perfusion was lower in patients with BMD, reflecting higher cardiovascular risk in this population. Whether early parathyroidectomy in the course of kidney disease could modify such results still deserves further investigation.

引言：骨代谢异常（bone metabolism disorder, BMD）与血管功能障碍是导致血液透析患者心血管死亡率居高不下的核心诱因。血管功能障碍作为动脉粥样硬化的新型标志物，在该群体的心血管风险中扮演着重要角色。尽管在普通人群中，此类血管功能评估与更高的死亡率显著相关，但针对血液透析患者的这类血管评估研究仍未得到充分开展。方法：本项横断面研究中，研究人员对血液透析患者实施了血流介导的舒张检测、心内膜下活力比值（subendocardial viability ratio, SEVR）以及射血时长指数评估，以明确骨代谢异常标志物对血管功能障碍的影响。结果：本研究纳入了匹配队列的患者，其中伴严重继发性甲状旁腺功能亢进（secondary hyperparathyroidism, SHPT）者16例，不伴严重SHPT者11例。此外，研究还评估了患者处于严重SHPT状态的累计时长。结果显示，伴严重SHPT的患者其SEVR水平更低，射血时长指数更高，提示其心血管风险更高。较低的SEVR水平还与舒张压（r=0.435, p=0.049）、血清25-羟维生素D水平（r=0.479, p=0.028）以及更长的严重SHPT持续时间（定义为从甲状旁腺激素>500pg/ml至甲状旁腺切除术或研究结束的时长，r=-0.642, p=0.027）显著相关。在针对SEVR与自变量的逐步多元回归分析中，在校正年龄、血清胆固醇水平与血压的模型中（校正后r²=0.545, p=0.001），更低的SEVR水平独立关联于更低的血清25-羟维生素D水平（p=0.005）、女性性别（p=0.012）以及更长的严重SHPT持续时间（p=0.001）。结论：骨代谢异常患者的心内膜下灌注水平更低，反映出该群体的心血管风险更高。在肾脏疾病病程中早期实施甲状旁腺切除术是否可改善此类结局，仍有待进一步的深入研究。