Gullestad L, Ross H, Myers J, Hoang K, Hunt S, Stinson E B, Valantine H A
Falk Cardiovascular Research Center, Stanford University School of Medicine, CA 94305-5246, USA.
Clin Transplant. 1997 Dec;11(6):628-32.
Studies in animals and humans have demonstrated that an increased heart rate is a predictor for the development of coronary atherosclerosis and overall cardiovascular mortality. In contrast, we have previously reported that the need for pacemaker implantation because of bradycardia in heart transplant recipients is associated with an increased prevalence of transplant coronary artery disease (TxCAD). Hence, the relevance of changes in heart rate to the development of TxCAD remains unclear. Intra-coronary ultrasound examinations (ICUS) were therefore analyzed in 130 heart transplant recipients (age 50 +/- 11 yr) studied at annual evaluations (3.7 +/- 3.0 yr after transplantation). Quantitative ultrasound measurements were obtained by calculating mean coronary artery intimal thickness (MIT) obtained by examination of the left anterior descending artery. The presence of TxCAD was defined as MIT > 0.3 mm. Resting heart rates (HR) were recorded with the patients in the supine position during routine echocardiography. Based on HR recordings, two groups were defined: group 1, HR below; or group 2, HR above the median. TxCAD was detected in 40% of the ICUS studies overall. The prevalence of TxCAD was higher in group 1 (49%) compared with group 2 (33%), p < 0.05. There was no significant difference in donor ischemic time or donor gender, recipient age, gender, body weight, CMV status, creatinine, total cholesterol, use of lipid lowering drugs or diltiazem. Donor age and use of beta-blockers were higher in group 1 compared with group 2 (29 +/- 10 vs. 25 +/- 9 yr, and 15% vs. 5%, for donor age and beta-blocker use, respectively). By multivariate regression analysis only donor age and years after transplantation were independently correlated with TxCAD. After excluding patients taking beta-blockers and diltiazem, the prevalence of CAD was still higher in group 1 (50%) vs. group 2 (34%). In conclusion, transplant coronary artery disease is more prevalent in patients with lower, rather than higher, heart rates. The reason for this is unclear, but may reflect impaired blood flow to the sinoatrial node.
对动物和人类的研究表明，心率加快是冠状动脉粥样硬化发展及总体心血管死亡率的一个预测指标。相比之下，我们之前曾报道，心脏移植受者因心动过缓而需要植入起搏器与移植冠状动脉疾病（TxCAD）患病率增加有关。因此，心率变化与TxCAD发展的相关性仍不明确。于是，我们对130名心脏移植受者（年龄50±11岁）进行了年度评估（移植后3.7±3.0年）时的冠状动脉内超声检查（ICUS）分析。通过计算检查左前降支获得的平均冠状动脉内膜厚度（MIT）来进行定量超声测量。TxCAD的存在定义为MIT>0.3mm。在常规超声心动图检查期间，让患者仰卧位记录静息心率（HR）。根据HR记录，分为两组：第1组，HR低于中位数；或第2组，HR高于中位数。总体ICUS研究中40%检测到TxCAD。第1组TxCAD患病率（49%）高于第2组（33%），p<0.05。供体缺血时间、供体性别、受者年龄、性别、体重、巨细胞病毒状态、肌酐、总胆固醇、降脂药物或地尔硫䓬的使用情况无显著差异。第1组供体年龄和β受体阻滞剂的使用高于第2组（供体年龄分别为29±10岁和25±9岁，β受体阻滞剂使用分别为15%和5%）。通过多因素回归分析，仅供体年龄和移植后年限与TxCAD独立相关。排除服用β受体阻滞剂和地尔硫䓬的患者后，第1组CAD患病率（50%）仍高于第2组（34%）。总之，移植冠状动脉疾病在心率较低而非较高的患者中更为普遍。其原因尚不清楚，但可能反映了窦房结血流受损。
