背景:由当代左心室辅助装置(LVAD)产生的连续流对肾血管生理学的影响尚不清楚。肾阻指数(RRI)反映动脉顺应性,以及肾血管阻力,由传入和传出小动脉张力贡献,肾间质以及肾静脉压.
方法:前瞻性,在基线(植入前)和3个月支持下进行肾多普勒评估的单中心研究。评估的结果包括术后肾脏替代疗法(RRT)的需要,肾功能恶化(WRF)定义为从植入前KDIGO慢性肾病阶段持续增加,右心室(RV)衰竭,和移植的存活率。
结果:植入前RRI不能预测心肾结局,包括右心衰竭,需要肾脏替代治疗或肾功能恶化。植入后RRI显著低于植入前RRI,具有明显的连续流动的多普勒波形特征。植入后肾舒张末期速度,但不是RRI,与LVAD流量密切相关(Spearmanrho-0.99,p<0.001),与平均动脉压呈相关趋势(Spearman’srho0.63,p=0.129)。植入后RRI与平均肺动脉压呈负相关(Spearman’srho-0.81,p=0.049),可能是由肺毛细血管楔压升高引起的(Spearman’srho-0.83,p=0.058)。
结论:LVAD支持患者中RRI的血流动力学因素是复杂的。在较低的RRI中观察到较高的平均肺动脉和肺毛细血管楔压可能反映出收缩期和舒张期流量的较小差异。未来对LVAD流出移植物和RRI的同时多普勒评估可能有助于了解有助于该指数的血液动力学相互作用。
BACKGROUND: The impact of continuous flow resulting from contemporary left ventricular assist devices (LVAD) on renal vascular physiology is unknown. Renal resistive index (RRI) reflects arterial compliance, as well as renal vascular resistance, contributed by afferent and efferent arteriolar tone, the renal interstitium as well as renal venous pressures.
METHODS: Prospective, single center study with renal Doppler evaluation at baseline (pre-implant) and at 3-months support. Outcomes assessed include need for post-operative renal replacement therapy (RRT), worsening renal function (WRF) defined as persistent increase from pre-implant KDIGO chronic kidney disease stage, right ventricular (RV) failure, and survival to transplantation.
RESULTS: Pre-implant RRI did not predict cardiorenal outcomes including right heart failure, need for renal replacement therapy or worsening renal function. Post-implant RRI was significantly lower than pre-implant RRI, with a distinct Doppler waveform characteristic of continuous flow. Post-implant renal end-diastolic velocity, but not RRI, correlated strongly with LVAD flow (Spearman rho -0.99, p < 0.001), with trend toward correlation with mean arterial pressure (Spearman\'s rho 0.63, p = 0.129). There was a negative correlation between post-implant RRI and mean pulmonary artery pressure (Spearman\'s rho -0.81, p = 0.049), likely driven by elevated pulmonary capillary wedge pressure (Spearman\'s rho -0.83, p = 0.058).
CONCLUSIONS: The hemodynamic contributors to RRI in LVAD supported patients are complex. Higher mean pulmonary artery and pulmonary capillary wedge pressures seen in lower RRI may reflect a smaller difference in systolic and diastolic flow. Future simultaneous Doppler assessment of the LVAD outflow graft and RRI may help understand the hemodynamic interactions contributing to this index.