The value of echocardiography in follow-up of human tissue valves in aortic position

The application of human tissue valves for aortic valve or root replacement was introduced during the 19608. The first successful clinical orthotopic implantation of an aortic allograft was performed by Ross and Barrat-Boyes independently in 19621,2, In 1967 Ross first reported the use of the pulmonary autograft in the subCOrOllai), position to replace a diseased aortic valvc3. The initial results of implantation of a freshly harvested allograft valve in the orthotopic position were generally good4, However, limited donor availability led to the development of preservation methods, like freeze-drying and fresh wet stotage at 4 oc. Concern about the transmission of infection initiated aggressive sterilization techniques: irradiation, highly concentrated antibiotic incubation and glutaraldehyde prctreatment2,S,6. Although these methods increased storage time and tissue availability, the clinical durability of dle allograft was dramatically infel10r to fresh untreated allografts4• During this period, reliable artificial heart valves were developed. They were available from the shelf and implantation was less demanding compared to the allograft and autograft implantation. The problems related to preservation and storage. and the development of aortic valve prostheses have delayed a widespread acceptance of human tissue valves. Improved sterilization methods and adequate hatvesting have improved the allograft durability since d,e carll' 1970s7-9, TIle development of cryoprcservation techniques by Angell and O'Brien has extended the duration of allograft storage in liquid nitrogen 10-12 The foundation of hcatt valve banks and the reported good longtetm clinical results in the late "19808 have initiated a renewed interest of cardiac surgeons in the usc of human tissue valves for aortic valve replacemenfS,10-12. Aortic allografts and autografts have advantages over mechanical and bioprothetic aortic valve prostheses due to their low incidence of endocarditis, thtombo-embolism, anticoagulation-related complications and improved durability compared with bioprostheses. However, their durability is still limited, compared with mechanical prostheses. The limited durability of human tissue valves is the main topic of clus thesis

Human tissue valves in aortic position: determinants of reoperation and valve regurgitation

BACKGROUND: Human tissue valves for aortic valve replacement have a limited durability that is influenced by interrelated determinants. Hierarchical linear modeling was used to analyze the relation between these determinants of durability and valve regurgitation measured by serial echocardiography. METHODS AND RESULTS: In adult patients, 218 cryopreserved aortic allografts were implanted with the subcoronary (85) or the root replacement technique (133), and 81 patients had root replacement with a pulmonary autograft. Mean follow-up was 4.2 years (SD 2.7; range, 0 to 10.5). Patient age, operator experience with subcoronary implantation, and allograft diameter were independent predictors for reoperation. With repeated color Doppler echocardiography, the severity of aortic regurgitation was assessed by the jet length method and the jet diameter ratio. Multilevel hierarchical linear modeling was used to estimate initial aortic regurgitation (intercept), its change over time (slope), and the effect of 11 potential determinants of durability on aortic regurgitation. With the jet length method, the intercept was 0.94 grade and the slope was 0.11 grade per year. With the jet diameter ratio, the intercept was 0.34 and the annual increase was 0.01. Subcoronary implanted valves had more initial aortic regurgitation, but progression of aortic valve regurgitation did not differ from root replacement. At midterm follow-up, recipient age <40 years was the only independent predictor of aortic regurgitation. CONCLUSIONS: Subcoronary implantation has a learning curve, resulting in more initial aortic regurgitation and early reoperation compared with root replacement. In both techniques, progression of aortic regurgitation over time is small but accelerated in young adults

Subcoronary implantation or aortic root replacement for human tissue valves: Sufficient data to prefer either technique?

The aortic root replacement technique with aortic allograft or pulmonary autograft might be superior to the subcoronary allograft implantation technique with regard to aortic regurgitation. We explored the influence of the learning process on the incidence of reoperation and the severity of postoperative aortic regurgitation as assessed by color Doppler echocardiography. The subcoronary implantation technique was used in 81 patients, and root replacement was done in 63 patients. The first 30 patients of each group were considered as the surgeons' learning curve. Reoperations were more common in the subcoronary implantation group. After exclusion of early reoperations, the median regurgitation score based on echocardiographic examination was 0.22 in the first 30 patients from the subcoronary implantation group and 0.14 in the root replacement group. The subsequent patients from these groups had regurgitation scores of 0.20 and 0.17, respectively. Statistical analysis of these data showed no significant difference. This interim report suggests that the learning curve for the surgical procedure and the grouping of echocardiographic data influence the interpretation of follow-up studies. The superiority of either technique with regard to aortic regurgitation has yet to be proved

Reduced right ventricular function on cardiovascular magnetic resonance imaging is associated with uteroplacental impairment in tetralogy of Fallot

BACKGROUND: Maternal right ventricular (RV) dysfunction (measured by echocardiography) is associated with impaired uteroplacental circulation, however echocardiography has important limitations in the assessment of RV function. We therefore aimed to investigate the association of pre-pregnancy RV and left ventricular (LV) function measured by cardiovascular magnetic resonance with uteroplacental Doppler flow parameters in pregnant women with repaired Tetralogy of Fallot (ToF). METHODS: Women with repaired ToF were examined, who had been enrolled in a prospective multicenter study of pregnant women with congenital heart disease. Clinical data and CMR evaluation before pregnancy were compared with uteroplacental Doppler parameters at 20 and 32 weeks gestation. In particular, pulsatility index (PI) of uterine and umbilical artery were studied. RESULTS: We studied 31 women; mean age 30 years, operated at early age. Univariable analyses showed that reduced RV ejection fraction (RVEF; P = 0.037 and P = 0.001), higher RV end-systolic volume (P = 0.004) and higher LV end-diastolic and end-systolic volume (P = 0.001 and P = 0.003, respectively) were associated with higher uterine or umbilical artery PI. With multivariable analyses (corrected for maternal age and body mass index), reduced RVEF before pregnancy remained associated with higher umbilical artery PI at 32 weeks (P = 0.002). RVEF was lower in women with high PI compared to women with normal PI during pregnancy (44% vs. 53%, p = 0.022). LV ejection fraction was not associated with uterine or umbilical artery PI. CONCLUSIONS: Reduced RV function before pregn

N-terminal pro-brain natriuretic peptide serum levels reflect attrition of the Fontan circulation

Objective:N-terminal pro-brain natriuretic peptide has an established role in the diagnosis and prognosis of heart failure. In Fontan patients, this peptide is often increased, but its diagnostic value in this particular non-physiologic, univentricular circulation is unclear. We investigated whether N-terminal pro-brain natriuretic peptide represents ventricular function or other key variables in Fontan patients.Methods and results:Ninety-five consecutive Fontan patients ≥10 years old who attended the outpatient clinic of the Center for Congenital Heart Diseases in 2012-2013 were included. Time since Fontan completion was 16 ± 9 years. Median N-terminal pro-brain natriuretic peptide was 114 (61-264) ng/l and was higher than gender-and age-dependent normal values in 54% of the patients. Peptide Z-scores were higher in patients in NYHA class III/IV compared to those in class I/II, but did not correlate with ventricular function assessed by MRI and echocardiography, nor with peak exercise capacity. Instead, peptide Z-scores significantly correlated with follow-up duration after Fontan completion (p < 0.001), right ventricular morphology (p = 0.004), indexed ventricular mass (p = 0.001), and inferior caval vein diameter (p < 0.001) (adjusted R2 = 0.615).Conclusions:N-terminal pro-brain natriuretic peptide levels in Fontan patients correlate with functional class, but do not necessarily indicate ventricular dysfunction. Increased peptide levels were associated with a longer existence of the Fonta