Department of Cardiac Surgery, University of Naples Federico II, Naples, Italy.
J Thorac Cardiovasc Surg. 2012 May;143(5):1030-5. doi: 10.1016/j.jtcvs.2011.06.011. Epub 2011 Jul 12.
Aortic valve replacement leads to improvement of coronary flow but not to complete normalization. Coronary hypoperfusion contributes to higher left ventricular mass persistence, arrhythmias, congestive heart failure and sudden death. This prospective study compares 2 similarly sized aortic prostheses (mechanical and porcine) regarding coronary flow and hemodynamic performances in patients who underwent surgery for pure aortic stenosis.
Sixty patients having undergone aortic valve replacement for pure aortic stenosis with Medtronic Mosaic Ultra bioprosthesis 21 mm (n = 30) or St Jude Regent mechanical valve 19 mm (n = 30) were evaluated preoperatively and 12 months postoperatively comparing the coronary flow and the hemodynamic behavior. Echocardiography and cardiac positron emission tomography were performed at rest and during exercise or adenosine maximal stimulation, respectively.
The St Jude Regent mechanical valve, compared with the Medtronic Mosaic Ultra bioprosthesis, had reduced coronary flow reserve (2.1 ± 0.3 vs 2.3 ± 0.2; P = .003), less favorable systolic/diastolic time ratio (0.87 ± 0.02 vs 0.78 ± 0.03; P < .001), and higher mean transprosthetic gradient (46 ± 11 vs 38 ± 9; P = .003) during exercise. Multivariate analysis of impaired coronary reserve related indexed effective orifice area less than 0.65 cm/m(2) (risk ratio [RR], 1.9; 95% confidence intervals [CI], 1.5-2.8; P < .001), mechanical valve (RR, 2.5; 95% CI, 1.7-3.3; P < .001), and systolic/diastolic time ratio greater than 0.75 (RR, 2.6; 95% CI, 1.8-3.8; P < .001), as well as high transprosthetic gradient (RR, 1.7; 95% CI, 1.3-2.4; P < .001) ) during exercise with coronary reserve less than 2.2.
Improvement of coronary flow and reserve was more evident for bioprostheses than for mechanical valves. The bioprostheses demonstrated superior hemodynamics during exercise, which may have some impact on exercise capability during normal daily life.
主动脉瓣置换可改善冠状动脉血流，但不能完全使之正常化。冠状动脉灌注不足可导致左心室质量持续增加、心律失常、充血性心力衰竭和猝死。本前瞻性研究比较了两种类似大小的主动脉假体（机械和猪）在接受单纯主动脉瓣狭窄手术的患者中的冠状动脉血流和血流动力学表现。
60 例接受主动脉瓣置换术治疗单纯主动脉瓣狭窄的患者，其中接受美敦力马赛克 Ultra 生物瓣 21mm（n=30）或圣犹达雷金机械瓣 19mm（n=30）治疗。分别在术前和术后 12 个月，通过超声心动图和心脏正电子发射断层扫描（PET），在休息和运动或腺苷最大刺激时评估冠状动脉血流和血流动力学情况。
与美敦力马赛克 Ultra 生物瓣相比，圣犹达雷金机械瓣的冠状动脉血流储备减少（2.1±0.3 比 2.3±0.2；P=0.003），收缩/舒张时间比更差（0.87±0.02 比 0.78±0.03；P<0.001），运动时平均跨瓣压差更高（46±11 比 38±9；P=0.003）。多变量分析显示，冠状动脉储备受损与指数有效瓣口面积小于 0.65cm/m2（风险比[RR]，1.9；95%置信区间[CI]，1.5-2.8；P<0.001）、机械瓣（RR，2.5；95%CI，1.7-3.3；P<0.001）和收缩/舒张时间比大于 0.75（RR，2.6；95%CI，1.8-3.8；P<0.001）以及运动时跨瓣压差高（RR，1.7；95%CI，1.3-2.4；P<0.001）有关。
生物瓣比机械瓣更能改善冠状动脉血流和储备。生物瓣在运动时表现出更好的血流动力学特性，这可能对日常生活中的运动能力有一定影响。
