Background Nonpulsatile pulmonary blood flow in Fontan circulation results in pulmonary vascular disease, but the potential relationships between pulmonary vascular resistance index (PVRI) and Fontan failure have not been studied. The objective was to determine whether the absence of subpulmonary ventricle in the Fontan circulation would make patients more vulnerable to even low-level elevations in PVRI, and when coupled with low cardiac index, this would identify patients at increased risk of Fontan failure.

Methods and Results Two hundred sixty-one adult Fontan patients underwent cardiac catheterization; age 26±3 years, men 146 (56%), atriopulmonary Fontan 144 (55%). Patients were divided into 2 groups: those with high PVRI (>2 WU·m²) and low cardiac index <2.5 L min⁻¹ m⁻² (group 1, n=70, 30%), and those with normal PVRI and normal cardiac index (group 2, n=182, 70%). Fontan failure was defined by the composite of all-cause mortality, listing for heart transplantation, or initiation of palliative care. There were 68 (26%) cases of Fontan failure during a mean follow-up of 8.6±2.4 years. When compared with group 2, freedom from Fontan failure was significantly lower in group 1: 66% versus 89% at 5 years. The combination of high PVRI and low cardiac index was an independent risk factor for Fontan failure (hazard ratio, 1.84; 95% confidence interval, 1.09–2.85).

Conclusions When coupled with low cardiac index, even mild elevations in PVRI identify patients at high risk of Fontan failure. This suggests that pulmonary vascular disease is a key mechanism underlying Fontan failure and supports further studies to understand the pathophysiology and target treatments to pulmonary vascular tone in this population.

中文翻译：

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Fontan 衰竭的血流动力学

背景Fontan 循环中的非搏动性肺血流会导致肺血管疾病，但肺血管阻力指数 (PVRI) 与 Fontan 衰竭之间的潜在关系尚未研究。目的是确定 Fontan 循环中肺下心室的缺失是否会使患者更容易受到 PVRI 低水平升高的影响，并且当与低心脏指数相结合时，这将识别 Fontan 衰竭风险增加的患者。

方法与结果261 名成人 Fontan 患者接受了心导管检查；年龄26±3岁，男性146（56%），房肺Fontan 144（55%）。患者被分为 2 组：高 PVRI (>2 WU·m ² ) 和低心脏指数 <2 id=124>−1 m ⁻²组（第 1 组，n=70，30%），以及正常组PVRI 和正常心脏指数（第 2 组，n=182，70%）。 Fontan 衰竭的定义是全因死亡率、心脏移植列表或姑息治疗启动的综合结果。在平均 8.6±2.4 年的随访期间，有 68 例（26%）Fontan 失败病例。与第 2 组相比，第 1 组的 Fontan 失败率明显较低：5 年时为 66% 对比 89%。高 PVRI 和低心脏指数的组合是 Fontan 衰竭的独立危险因素（风险比，1.84；95% 置信区间，1.09-2.85）。

结论当与低心脏指数相结合时，即使 PVRI 轻微升高，也可识别出 Fontan 衰竭高风险患者。这表明肺血管疾病是 Fontan 衰竭的关键机制，并支持进一步研究以了解该人群的病理生理学和针对肺血管张力的靶向治疗。