Zierer Andreas, Melby Spencer J, Voeller Rochus K, Moon Marc R
Division of Cardiothoracic Surgery, Washington Univ. School of Medicine, 3108 Queeny Tower, #1 Barnes-Jewish Plaza, St. Louis, Missouri 63110-1013, USA.
Am J Physiol Heart Circ Physiol. 2009 Mar;296(3):H639-44. doi: 10.1152/ajpheart.00496.2008. Epub 2009 Jan 9.
The purpose of the present study was to determine for the first time the qualitative and quantitative impact of varying degrees of interatrial shunting on right heart dynamics and systemic perfusion in subjects with chronic pulmonary hypertension (CPH). Eight dogs underwent 3 mo of progressive pulmonary artery banding, following which right atrial and ventricular end-systolic and end-diastolic pressure-volume relations were calculated using conductance catheters. An 8-mm shunt prosthesis was inserted between the superior vena cava and left atrium, yielding a controlled model of atrial septostomy. Data were obtained 1) preshunt or "CPH"; 2) "Low-Flow" shunt; and 3) "High-Flow" shunt (occluding superior vena cava forcing all flow through the shunt). With progressive shunting, right ventricular pressure fell from 72 +/- 19 mmHg (CPH) to 54 +/- 17 mmHg (Low-Flow) and 47 +/- 17 mmHg (High-Flow) (P < 0.001). Cardiac output increased from 1.5 +/- 0.3 l/min at CPH to 1.8 +/- 0.4 l/min at Low-Flow (286 +/- 105 ml/min, 15% of cardiac output; P < 0.001), but returned to 1.6 +/- 0.3 l/min at High-Flow (466 +/- 172 ml/min, 29% of cardiac output; P = 0.008 vs. Low-Flow, P = 0.21 vs. CPH). There was a modest rise in systemic oxygen delivery from 252 +/- 46 ml/min at CPH to 276 +/- 50 ml/min at Low-Flow (P = 0.07), but substantial fall to 222 +/- 50 ml/min at High-Flow (P = 0.005 vs. CPH, P < 0.001 vs. Low-Flow). With progressive shunting, bichamber contractility did not change (P = 0.98), but the slope of the right atrial end-diastolic pressure volume relation decreased (P < 0.04), consistent with improved compliance. This study demonstrated that Low-Flow interatrial shunting consistently improved right atrial mechanics and systemic perfusion in subjects with CPH, while High-Flow exceeded an "ideal shunt fraction".
本研究的目的是首次确定不同程度的心房分流对慢性肺动脉高压（CPH）患者右心动力学和体循环灌注的定性和定量影响。八只犬接受了3个月的渐进性肺动脉环扎术，之后使用电导导管计算右心房和心室的收缩末期和舒张末期压力-容积关系。在 superior vena cava（上腔静脉）和左心房之间插入一个8毫米的分流假体，建立了一个可控的房间隔造口术模型。在以下三个阶段获取数据：1）分流前或“CPH”阶段；2）“低流量”分流阶段；3）“高流量”分流阶段（阻塞上腔静脉，迫使所有血流通过分流）。随着分流的进展，右心室压力从CPH阶段的72±19 mmHg降至“低流量”阶段的54±17 mmHg和“高流量”阶段的47±17 mmHg（P<0.001）。心输出量从CPH阶段的1.5±0.3升/分钟增加到“低流量”阶段的1.8±0.4升/分钟（286±105毫升/分钟，占心输出量的15%；P<0.001），但在“高流量”阶段又回到1.6±0.3升/分钟（466±172毫升/分钟，占心输出量的29%；与“低流量”阶段相比，P = 0.008，与CPH阶段相比，P = 0.21）。体循环氧输送量从CPH阶段的252±46毫升/分钟适度增加到“低流量”阶段的276±50毫升/分钟（P = 0.07），但在“高流量”阶段大幅下降至222±50毫升/分钟（与CPH阶段相比，P = 0.005，与“低流量”阶段相比，P<0.001）。随着分流的进展，双腔收缩性没有变化（P = 0.98），但右心房舒张末期压力-容积关系的斜率降低（P<0.04），这与顺应性改善一致。本研究表明，低流量心房分流持续改善了CPH患者的右心房力学和体循环灌注，而高流量分流超过了“理想分流分数”。
