Godfrey Max E, Rathod Rahul H, Keenan Ellen, Gauvreau Kimberlee, Powell Andrew J, Geva Tal, Prakash Ashwin
Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.
Department of Pediatrics, Harvard Medical School, Boston, MA, USA.
Pediatr Cardiol. 2018 Apr;39(4):763-773. doi: 10.1007/s00246-018-1819-6. Epub 2018 Feb 5.
The ventriculoarterial coupling (VAC) ratio, the ratio of arterial elastance (Ea) to ventricular end-systolic elastance (Ees), reflects cardiovascular efficiency. Little is known about this ratio in patients who have undergone the Fontan procedure. Our aim was to assess the VAC ratio in a cohort of Fontan patients using a cardiac magnetic resonance (CMR) method, and to examine its relation to outcomes. We retrospectively assessed VAC from CMR data on 195 Fontan patients (age 19.6 ± 10.7 years) and 42 controls (age 15.2 ± 2.2 years). The VAC ratio was calculated as Ea/Ees (Ea = mean arterial blood pressure (MBP)/ventricular stroke volume; Ees = MBP/end-systolic volume). Compared with controls, Fontan patients had lower body surface area-adjusted median Ees (1.54 vs. 2.4, p < 0.001) and Ea (1.35 vs. 1.48, p = 0.01), and a higher median VAC ratio (0.88 vs. 0.62, p < 0.001). After a median follow-up of 4 years (range 1-10), 20 patients reached a composite endpoint of death or heart transplant listing. On multivariable modeling, being in the lowest tertile of the VAC ratio was independently associated with the composite endpoint (odds ratio 11.39, p = 0.02), and inclusion of the VAC ratio in the model improved prediction compared to traditional risk factors. In patients without ventricular dilation, the VAC ratio was the only factor predictive of the composite endpoint (p = 0.02). In conclusion, we found evidence for inefficient ventriculoarterial coupling in Fontan patients. The VAC ratio improved prediction of outcomes and was especially useful in patients without ventricular dilation. Further investigation into the clinical significance of ventriculoarterial coupling in this patient population is warranted.
心室动脉耦联（VAC）比率，即动脉弹性（Ea）与心室收缩末期弹性（Ees）的比率，反映了心血管效率。对于接受Fontan手术的患者，关于这一比率的了解甚少。我们的目的是使用心脏磁共振（CMR）方法评估一组Fontan患者的VAC比率，并研究其与预后的关系。我们回顾性地从195例Fontan患者（年龄19.6±10.7岁）和42例对照者（年龄15.2±2.2岁）的CMR数据中评估VAC。VAC比率计算为Ea/Ees（Ea = 平均动脉血压（MBP）/心室每搏输出量；Ees = MBP/收缩末期容积）。与对照者相比，Fontan患者经体表面积调整后的Ees中位数较低（1.54对2.4，p < 0.001），Ea也较低（1.35对1.48，p = 0.01），而VAC比率中位数较高（0.88对0.62，p < 0.001）。在中位随访4年（范围1 - 10年）后，20例患者达到了死亡或列入心脏移植名单的复合终点。在多变量建模中，处于VAC比率最低三分位数与复合终点独立相关（比值比11.39，p = 0.02），并且与传统危险因素相比，将VAC比率纳入模型可改善预测。在无心室扩张的患者中，VAC比率是复合终点的唯一预测因素（p = 0.02）。总之，我们发现Fontan患者存在心室动脉耦联效率低下的证据。VAC比率改善了对预后的预测，在无心室扩张的患者中尤其有用。有必要进一步研究该患者群体中心室动脉耦联的临床意义。
