Will heart valve tissue engineering change the world?
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Bioprosthesis↗
Biomedical subjects
J J M Takkenberg
Publications and source records attributed to J J M Takkenberg.
Comparison of outcomes after aortic valve replacement with a mechanical valve or a bioprosthesis using microsimulation.
BACKGROUND: Mechanical valves and bioprostheses are widely used for aortic valve replacement. Though previous randomised studies indicate that there is no important difference in outcome after implantation with either type of valve, knowledge of outcomes after aortic valve replacement is incomplete. OBJECTIVE: To predict age and sex specific outcomes of patients after aortic valve replacement with bileaflet mechanical valves and stented porcine bioprostheses, and to provide evidence based support for the choice of prosthesis. METHODS: Meta-analysis of published results of primary aortic valve replacement with bileaflet mechanical prostheses (nine reports, 4274 patients, and 25,726 patient-years) and stented porcine bioprostheses (13 reports, 9007 patients, and 54,151 patient-years) was used to estimate the annual risks of postoperative valve related events and their outcomes. These estimates were entered into a microsimulation model, which was employed to calculate age and sex specific outcomes after aortic valve replacement. RESULTS: Life expectancy (LE) and event-free life expectancy (EFLE) for a 65 year old man after implantation with a mechanical valve or a bioprosthesis were 10.4 and 10.7 years and 7.7 and 8.4 years, respectively. The lifetime risk of at least one valve related event for a mechanical valve was 48%, and for a bioprosthesis, 44%. For LE and EFLE, the age crossover point between the two valve types was 59 and 60 years, respectively. CONCLUSIONS: Meta-analysis based microsimulation provides insight into the long term outcome after aortic valve replacement and suggests that the currently recommended age threshold for implanting a bioprosthesis could be lowered further.
Aged↗
Excessive pulmonary autograft dilatation causes important aortic regurgitation.
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Adult↗
[Coronary bypass surgery in 1971-80 and 1995-96: increased age and comorbidity, unchanged survival rates and fewer early reoperations 1 and 5 years postoperatively].
OBJECTIVE: To describe the characteristics of patients undergoing coronary bypass surgery (CABG) over the past 30 years and the outcome after 1 and 5 years. DESIGN: Retrospective. METHOD: All 1041 patients who had undergone a first CABG in the Thorax centre of the Erasmus Medical Centre in Rotterdam during the period from 1 July 1971 through 31 May 1980 (group I) were compared with all patients who had also undergone such a first operation during the period between 1 September 1995 and 31 December 1996 (group II). Data on the patients, the operations, any reoperations and the mortality were obtained from patient records, from general practitioners and from municipal archives. Cumulative percentages of survival and of not having reCABG or percutaneous transluminal coronary angioplasty (PTCA) were analysed by using the Kaplan-Meier-method. RESULTS: The patients in group I were 11 years younger on average than those in group II and there were more men (group I: 88%, group II: 76%). The patients in group II had more comorbidity than those in group I. The actuarial perioperative mortality was 1.2% in group I and 1.6% in group II. The overall 5-year mortality was significantly lower in group I than in group II (9.1% vs. 11.0%). After adjustment for the baseline characteristics, however, the patients in group II had a lower risk of mortality. Coronary revascularisation in the first 5 years was required more often in group I than in group II (7.4% vs. 4.2%). Independent predictors of a higher 5-year mortality were: a reduced ejection fraction (both groups), more extensive vascular disease (group I), chronic pulmonary disease, renal function disorders and diabetes mellitus (all group II), while treatment for hyperlipidaemia had a favourable effect on survival. CONCLUSION: The age and comorbidity of the operated patients had increased over the years, while the chance of survival was no less than before and there was less chance of an early reoperation.
Adult↗
Evolution of allograft aortic valve replacement over 13 years: results of 275 procedures.
OBJECTIVE: We describe our center's experience with the use of allografts for aortic valve or root replacement, illustrating the impact on outcome of the changes made in surgical and preservation techniques. METHODS: Between 4/1987 and 1/2001 275 allografts were used in 267 consecutive patients to replace the aortic valve or root. All patients were prospectively followed over time. Mean patient age was 46 years (SD 16; range 0.06-83), male/female ratio was 201/74. Prior cardiac operations took place in 73 patients; 49 patients presented with active endocarditis. Pre-operative NYHA-class was III in 51%. Initially, the subcoronary technique was used (SC; N=95) while in recent years root replacement (ARR; N=180) became the technique of choice. Seven fresh (two pulmonary and five aortic) and 268 cryopreserved (four pulmonary and 264 aortic; 35 glycerol and 233 DMSO) allografts were implanted. Concomitant procedures took place in 133 (48%). RESULTS: Operative mortality was 5.5% (N=15) and during follow-up (99% complete) 29 more patients died. Overall cumulative survival was 73% (95% CI 65-81%) at 9 years postoperative and significantly better for SC compared to ARR patients (P=0.005). Freedom from allograft-related reoperation (N=34) was 77% (95% CI 69-85) at 9 years, and worse in the SC compared to ARR group due to increased early technical failure (P=0.03). Freedom from reoperation for structural valve deterioration (SVD; N=22) was 81% (95% CI 73-89) at 9 years and did not differ between SC and ARR (P=0.51). Independent predictors of degenerative SVD were younger patient age (HR 0.93 with age as continuous variable; 95% CI 0.90-0.97), older donor age (HR 1.06 with age as a continuous variable; 95% CI 1.00-1.11), larger allograft diameter (HR 1.38; 95% CI 1.11-1.71) and the use of pulmonary allografts (HR 10.72; 95% CI 3.88-29.63). Calculated median time to reoperation for structural valve deterioration ranged from 23 years in a 65-year-old patient to 12 years in a 25-year-old. CONCLUSIONS: Aortic valve replacement with allografts yields adequate midterm results. Although important changes have been made over the years to improve durability, allografts still have a limited life span especially in young patients.
Adolescent↗
Short-term and 5-year outcome after primary isolated coronary artery bypass graft surgery: results of risk stratification in a bilocation center.
OBJECTIVE: We retrospectively investigated the short and mid-term outcome of non-emergent primary isolated coronary artery bypass graft (CABG) surgery in relation to risk stratification in the fully equipped university location (FE) and the low volume, limited facility location (LVLF) of our department. METHODS: Between September 1995 and December 1996, 832 patients were referred to our department to undergo a primary isolated CABG operation. The surgical team selected 482 patients (58%) as being at low-risk. These were treated in the LVLF hospital. The other 350 patients with mixed-risk were treated in the FE hospital. The selection consisted primarily of exclusion of patients with moderate or poor left ventricular function, severe COPD or renal impairment, from surgery in the LVLF location. Finally, the prognostic value of the EuroSCORE and the Parsonnet score was tested on our patient population. RESULTS: Overall in-hospital mortality was 1.6% (13 patients). One patient died in the LVLF group (0.2%) and 12 patients (3.4%) in the FE group. LVLF patients experienced less complications during the hospital period compared to the FE patients (5 versus 21%; P=0.0001). The Parsonnet risk model and the EuroSCORE risk model showed both a good relation with in-hospital mortality. After discharge, an increased risk of late mortality was observed up to 1 year postoperative in the FE group compared to the LVLF group (2.7 versus 0.5%; P=0.01). Risk factors for 5-year mortality were pre-operative renal impairment (blood creatinine >150 micromol/l) (hazard ratio (HR): 2.8; 95% confidence interval (CI): 1.4-5.5), diabetes (HR: 2.1; 95% CI: 1.3-3.5), impaired LVEF (HR: 1.9; 95% CI: 1.2-3.0), COPD (HR: 1.9; 95% CI: 1.1-3.5) and older age (HR: 1.07 per year; 95% CI: 1.01-1.10). Lipid-lowering therapy was a predictor of lower mortality at 5-years (HR: 0.5; 95% CI: 0.4-0.9). CONCLUSION: By careful decision making, selection of low-risk patients for a low volume and limited facility location resulted in excellent in-hospital survival with very low complication rates.
Adult↗
Report of the Dutch experience with the Ross procedure in 343 patients.
OBJECTIVE: Limited information is available on outcome after autograft aortic valve replacement, in particular with respect to the durability of the autograft and of the allograft used to reconstruct the right ventricular outflow tract. A retrospective follow-up study of all patients who underwent a Ross procedure in the Netherlands since 1988 was done to obtain an overview of the Dutch experience with this procedure. METHODS: From 1988 to January 2000, 348 Ross procedures were performed in nine centers in the Netherlands. Pre-operative, peri-operative and follow-up data from 343 patients in seven centers (99% of all Dutch autograft patients) were collected and analyzed. RESULTS: Mean patient age was 26 years (SD 14, range 0-58) and male/female ratio was 2.1. Bicuspid valve or other congenital heart valve disease was the most common indication for operation. The root replacement technique was used in 95% of patients and concomitant procedures were done in 12%. Hospital mortality was 2.6% (N=9). Mean follow-up was 4 years (median 3.8, SD 2.8, range 0-12.5). Overall cumulative survival was 96% at 1 year (95% confidence interval (CI) 94-98%) and 94% at 5 and 7 post-operative years, respectively (95% CI 91-97%). At last follow-up, 87% of the surviving patients was in New York Heart Association (NYHA) class I. Independent predictors of overall mortality were pre-operative NYHA class IV/V and longer perfusion time. Autograft reoperation had to be performed in 14 patients and reintervention on the pulmonary allograft in 10 patients. Freedom from any valve-related reintervention was 88% at 7 years (95% CI 81-94%). CONCLUSIONS: The Dutch experience with the Ross procedure is favorable, with low operative mortality and good mid-term results. Although both the autograft in aortic position and the allograft in the right ventricular outflow tract have a limited durability, this has not yet resulted in considerable reoperation rates and associated morbidity and mortality.
Adolescent↗