PubMed · 14449765
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C A HUFNAGEL. 1961. Aortic insufficiency.. https://doi.org/10.1016/s0033-0620(61)80019-4
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AIM OF THE STUDY: Several studies have shown the inferior performance of small prostheses in the narrow aortic root. However, modern low-profile mechanical prostheses have improved hemodynamic performance characteristics. By measuring the transprosthetic pressure gradient in vivo, we were able to characterize the hemodynamic features of two prostheses: the ATS Medical (ATS) and the Medtronic Hall (MH) valves. METHODS: From October 1994 to April 2002, 113 patients received an aortic valve replacement (AVR) with either an ATS or a MH valve. The transprosthetic pressure gradients, calculated from a simplified Bernoulli equation during immediate postoperative Doppler echocardiographic examination, were compared for differently sized prostheses with respect to body surface area (BSA). RESULTS: The mean pressure gradients and the mean BSAs were: 27.8 +/- 14.8 mm Hg and 1.50 +/- 0.10 m(2) in ATS 19 mm (n = 7), 20.4 +/- 8.5 mm Hg and 1.54 +/- 0.11 m(2) in ATS 21 mm (n = 22), 13.0 +/- 5.7 mm Hg, 1.70 +/- 0.13 m(2) in ATS 23 mm (n = 22), 10.9 +/- 3.5 mm Hg and 1.81 +/ -0.16 m(2) in ATS 25 mm (n = 19), 9.3 +/- 0.6 mm Hg and 1.72 +/- 0.17 m(2) in ATS 27 mm (n = 4), 13.5 +/- 6.5 mm Hg and 1.54 +/- 0.13 m(2) in MH 20 mm (n = 9), 10.9 +/- 4.7 mm Hg and 1.64 +/- 0.15 m(2) in MH 22 mm (n = 22), 9.3 +/- 3.1 mm Hg and 1.72 +/- 0.12 m(2) in MH 24 mm (n = 7). CONCLUSIONS: With the exception of the ATS 19-mm valve, the variously sized prostheses have acceptable transprosthetic pressure gradient measurements. In addition, even-sized MH valves (20 and 22 mm) with a thinner sewing cuff showed better hemodynamic performances than similarly sized ATS valves.
BACKGROUND: Transcatheter balloon aortic valvuloplasty (BAVP) has become the first-line treatment for critical aortic stenosis (AS) in neonates. However, little is known about the growth and function of left heart structures or about patterns of reintervention on the left heart after neonatal BAVP. METHODS AND RESULTS: Between 1985 and 2002, 113 patients underwent neonatal BAVP at < or =60 days of age. There were 16 early deaths (14%), with a significant decrease from 1985 to 1993 (22%) to 1994 to 2002 (4%), and 6 patients had successful early conversion to a univentricular circulation. In the short term, the mean relative gradient reduction was 54+/-26%, and significant aortic regurgitation (AR) developed in 15% of patients. The 91 early survivors with a biventricular circulation were followed up for 6.3+/-5.3 years, during which time there was a steady increase in the frequency of significant AR. Freedom from moderate or severe AR was 65% at 5 years. In almost all patients with a baseline aortic annulus z score less than -1, the annulus diameter increased to within the normal range within 1 to 2 years. Similarly, left ventricular (LV) end-diastolic dimension z scores, which ranged from -5 to 7.5 before BAVP, normalized within 1 to 2 years in nearly all patients with a predilation z score less than -1. Among early survivors with a biventricular circulation, reintervention-free survival on the LV outflow tract was 65% at 1 year and 48% at 5 years, with younger age, higher pre- and post-BAVP gradients, and a larger balloon-annulus diameter ratio associated with decreased reintervention-free survival (P<0.01). Seventeen surgical interventions were performed on the aortic valve in 15 patients, including replacement in 7. Survival free from aortic valve replacement was 84% at 5 years. CONCLUSIONS: BAVP for AS during the first 60 days of life results in short-term relief of AS in the majority of patients. Among early survivors, initially small left heart structures may be associated with worse subacute outcomes but typically normalize within 1 year. Reintervention for residual/recurrent AS or iatrogenic AR is relatively common, particularly during the first year after BAVP, but aortic valve replacement during early childhood is seldom necessary.
OBJECTIVE: Biological valves exhibit characteristic curves (CC) regarding transvalvular gradient, resistance, and effective orifice area when correlated with a physiological cardiac output range (CO). The slope of the curve of transvalvular resistance over a typical CO range characterizes the clinical performance of the valve. These information may support an individualized decision towards the most adequate valve type. METHODS: In an extracorporeal mock circuit two types of stented biological aortic valves (constructed pericardial valves, Edwards Perimount: EP; porcine cusp valves, Medtronic Mosaic: MM) of 21, 23, and 25 mm were investigated. Mean transvalvular gradient was measured over a range of 1.9 to 7.2l/min CO at a simulated heart rate of 70 beats/min. Transvalvular resistance was calculated and presented as characteristic curves in a log-log-plot against cardiac output. RESULTS: EP valves of all sizes demonstrated low slopes (resistance range; slope: 21 mm: 53-79 dynes s cm(-5); 0.29; 23 mm: 44-56 dynes s cm(-5); 0.12; 25 mm: 38-45 dynes s cm(-5); 0.12) while MM valves exhibited steep slopes (resistance range; slope: 21 mm: 46-169 dynes s cm(-5); 0.97; 23 mm: 36- -146 dynes s cm(-5); 0.95; 25 mm: 27-64 dynes s cm(-5); 0.68). CONCLUSIONS: While constructed pericardial valves demonstrate sufficient hemodynamic performance especially in the higher CO range porcine cusp valves exhibited minor resistance in the lower CO range. Patients who exercise regularly may therefore profit from a pericardial valve while patients with a small body surface area and little exercise who therefore remain in the lower CO range may be adequately treated with a porcine cusp valve.