Department of Cardiovascular Surgery, Shenyang Northern Hospital, Shenyang, Liaoning Province, China.
Ann Thorac Surg. 2012 Feb;93(2):620-5. doi: 10.1016/j.athoracsur.2011.10.001.
Right-side heart function is essentially externalized during extracardiac total cavopulmonary connection. The Fontan procedure has a certain impact on pulmonary hemoperfusion and may explain various postsurgical complications. In this study, alterations of pulmonary perfusion in patients undergoing the Fontan procedure were analyzed at the 5-year postoperative mark by radionuclide imaging and angiocardiography, and results of both methods were compared.
For 43 post-Fontan patients, perfusion ratios of each lung segment were calculated based on radionuclide imaging data. The pulmonary vascular resistance and pulmonary artery index of each patient were also calculated from right angiocardiographic measurements.
The radionuclide count and advantage perfusion ratio of right lung at follow-up did not differ significantly from early postoperative values (t=0.38, p>0.05; t=1.12, p>0.05), and superior/inferior vena cava perfusion ratios were stable (t=0.88, p>0.05; t=0.74, p>0.05). The superior/inferior segment perfusion ratio of the whole lung declined significantly (t=2.54, p<0.05), while that of the dorsal lung segment rose significantly (t=2.16, p<0.05). Compared with early postoperative status, the pulmonary arterial index of patients at follow-up were significantly increased (t=2.41, p<0.05), while small pulmonary vascular resistances declined significantly (t=2.08, p<0.05; t=2.69, p<0.05), and arterial oxygen saturation levels were unaltered (t=1.12, p>0.05). The early angiographic and radionuclide perfusion studies of 5 patients did not match.
After the Fontan procedure, hypostatic redistribution of pulmonary blood flow is characteristic. The weak pulse of blood, in the absence of ventricular ejection, can promote pulmonary vascular changes, but at later (intermediate) follow-up, the decline in vascular resistance that results carries no benefit in terms of blood perfusion or oxygenation. Microcirculatory arteriovenous shunting is the likely cause. In this study of functional pulmonary hemoperfusion, radionuclide imaging was deemed superior to angiocardiography.
右心功能在心脏外全腔静脉-肺动脉连接过程中基本外化。法乐四联症根治术后对肺血液灌注有一定影响，可能解释了各种术后并发症。在这项研究中，通过放射性核素成像和心血管造影术分析了 5 年后接受法乐四联症根治术患者的肺灌注变化，并比较了两种方法的结果。
对 43 例法乐四联症根治术后患者，根据放射性核素成像数据计算每个肺段的灌注比。还根据右心心血管造影测量结果计算每位患者的肺血管阻力和肺动脉指数。
随访时右肺的放射性核素计数和优势灌注比与术后早期无显著差异（t=0.38，p＞0.05；t=1.12，p＞0.05），上、下腔静脉灌注比稳定（t=0.88，p＞0.05；t=0.74，p＞0.05）。全肺的上、下肺段灌注比显著下降（t=2.54，p＜0.05），而背侧肺段灌注比显著上升（t=2.16，p＜0.05）。与术后早期相比，患者随访时的肺动脉指数显著升高（t=2.41，p＜0.05），而小肺血管阻力显著下降（t=2.08，p＜0.05；t=2.69，p＜0.05），动脉血氧饱和度水平不变（t=1.12，p＞0.05）。5 例患者的早期血管造影和放射性核素灌注研究不匹配。
法乐四联症根治术后，肺血流的低位置重新分配是特征性的。由于没有心室射血，血液的微弱搏动可促进肺血管变化，但在后期（中期）随访时，血管阻力下降对血液灌注或氧合没有益处。微循环动静脉分流可能是原因。在这项功能性肺血液灌注研究中，放射性核素成像被认为优于心血管造影术。
