Outcome after aortic valve replacement in young adults: is patient profile more important than prosthesis type?

BACKGROUND AND AIM OF THE STUDY

The optimal prosthesis choice in young adults requiring aortic valve replacement (AVR) remains controversial. The study aim was to determine whether implanted prosthesis type is an important determinant of outcome after AVR in young adults.

METHODS

Between 1991 and 2001, 414 young adults (mean age 40 +/- 11 years; range: 16-55 years) underwent a total of 438 consecutive AVRs using 204 mechanical prostheses (MP), three bioprostheses (BP), 150 allografts (AL), and 81 autografts (AU). The perioperative characteristics, early and late mortality, occurrence of valve-related events and predictors of adverse outcome and prosthesis selection, were evaluated.

RESULTS

Mean patient ages were 45 years for MP, 50 years for BP, 39 years for AL, and 31 years for AU. MP selection was associated with older age, impaired left ventricular function (LVF) and concomitant mitral valve surgery (concMVS); AL selection with ascending aortic aneurysm, active endocarditis, and Marfan's disease; and AU selection with younger age, prior balloon valvuloplasty and isolated valve disease. Hospital mortality was 2.3% (n = 10). During follow up (97% complete) 30 patients died. Ten-year survival was better for AU (96 +/- 2%) compared to MP (84 +/- 4%) and AL (92 +/- 2%). Prosthesis type was not predictive of late mortality; rather, predictors of increased late mortality were prior aortic valve surgery, impaired LVF, concMVS, and older patient age. Ten-year freedom from bleeding and thromboembolism was 89 +/- 3% for MP versus 94 +/- 3% for AL and 99 +/- 1% for AU (p = 0.054). Ten-year freedom from reoperation was 95 +/- 2% for MP versus 79 +/- 5% for AL and 87 +/- 5% for AU (p = 0.003).

CONCLUSION

Survival after AVR in young adults in Rotterdam was mainly determined by patient-related factors, and not by prosthesis type. A randomized controlled trial is necessary to determine whether valve prosthesis type indeed plays a crucial role in improving survival in young adult patients.

Does the type of biological valve affect patient outcome?

Patient background mortality and excess mortality related to aortic valve disease may play a greater role than implanted valve type in explaining the observed survival differences after aortic valve replacement. This study attempts to identify the differences between the performance of selected biological valves, given similar patient characteristics and excess mortality. Four biological valve types, the Carpentier-Edwards pericardial and supra-annular valve, Medtronic Freestyle valve and allografts were used for this analysis. Primary data calculated observed patient-survival and median time to structural valvular deterioration. We then used a microsimulation model to calculate age-specific patient survival and reoperation- and event-free life expectancies. The model incorporated the US population mortality and a uniform excess mortality, while the hazards of valve-related events after implantation of the four valve types were estimated from corresponding meta-analysis and primary data. Observed 10-year survival (60-69)-year age group survival and median time to SVD for the different valve types did not differ. Microsimulation calculated, for a 65-year-old male for example, a 10-year survival of 51%, 51%, 53% and 56% for Carpentier-Edwards pericardial and Supra-annular valve, Freestyle and allografts, respectively. Patient life expectancy was 10.8, 10.8, 11.0 and 11.4 years, respectively. Assuming uniform patient characteristics and excess mortality, the observed difference in performance between the four biological valve types is less marked. Patient selection and the timing of operation may explain most of the observed differences in prognosis after aortic valve replacement with biological prostheses.

Comparison of Carpentier-Edwards pericardial and supraannular bioprostheses in aortic valve replacement

OBJECTIVE

This study aimed at calculating and comparing the long-term outcomes of patients after aortic valve replacement with the Carpentier-Edwards bovine pericardial and porcine supraannular bioprostheses using microsimulation.

METHODS

We conducted a meta-analysis of eight studies on the Carpentier-Edwards pericardial valves (2,685 patients, 12,250 patient-years) and five studies on the supraannular valves (3,796 patients, 20,127 patient-years) to estimate the occurrence rates of valve-related events. Eighteen-year follow-up data sets were used to construct age-dependent Weibull curves that described their structural valvular deterioration. The estimates were entered into a microsimulation model, which was used to calculate the outcomes of patients after aortic valve replacement.

RESULTS

The annual hazard rates for thrombo-embolism after aortic valve replacement were 1.35% and 1.76% for the pericardial and supraannular valves, respectively. For a 65-year-old male, median time to structural valvular deterioration was 20.1 and 22.2 years while the lifetime risk of reoperation due to structural valvular deterioration was 18.3% and 14.0%, respectively. The life expectancy of the patient was 10.8 and 10.9 years and event-free life expectancy 9.0 and 8.8 years, respectively.

CONCLUSIONS

The microsimulation methodology provides insight into the prognosis of a patient after aortic valve replacement with any given valve type. Both the Carpentier-Edwards pericardial and supraannular valve types perform satisfactorily, especially in elderly patients, and show no appreciable difference in long-term outcomes when implanted in the aortic position.

Serial echocardiographic assessment of neo-aortic regurgitation and root dimensions after the modified Ross procedure

BACKGROUND AND AIM OF THE STUDY

Concern exists regarding progressive root dilatation after the modified Ross procedure. The present prospective echocardiographic study aimed to provide further insight into neo-aortic regurgitation (nAR) and neoaortic root dimensions over time in adult Rotterdam Ross root patients, and to study potential risk factors for nAR and dilatation.

METHODS

All Rotterdam Ross patients aged > or = 16 years at surgery were subjected to a prospective biennial standardized echocardiographic protocol. Analysis over time of nAR according to the jet length and jet diameter method, autograft annulus and sinotubular junction (STJ) diameters was carried out using a multilevel linear model in 90 patients who had two or more echocardiographic measurements (mean 5; range 2-9; total 458) up to 14 years (mean 7 years) after surgery.

RESULTS

The mean (+/- SE) initial postoperative jet length nAR was grade 0.9 +/- 0.09, and the annual increase 0.1 +/- 0.02 (p < 0.001). Initial annulus and STJ diameters were 25 +/- 0.5 mm and 36 +/- 0.6 mm, while annual increases were 0.4 +/- 0.07 mm and 0.5 +/- 0.09 mm, respectively (p < 0.001). Patients who eventually underwent an autograft reoperation (n = 10) had significantly greater initial nAR and greater progression of nAR, and a greater initial annulus diameter. The annual annulus and STJ diameter increase was greater in patients who underwent autograft reoperation. Compared to freestanding root replacement, patients with inclusion cylinder aortic root replacement had smaller initial annulus and STJ diameters that did not increase over time. Female gender was associated with a greater initial jet length and jet diameter nAR and a greater increase over time in jet diameter nAR. Preoperative aortic regurgitation or combined aortic stenosis and regurgitation were associated with greater initial annulus and STJ diameters. Neither bicuspid valve disease, patient age, preoperative ascending aorta aneurysm, prior aortic valve surgery nor hypertension had an effect on initial or progression of nAR, annulus, and STJ diameter.

CONCLUSION

The annual increase in nAR and root dimensions is small, but persistent, after autograft aortic root replacement in adults, and further reoperations should be anticipated. Use of the inclusion cylinder root replacement technique seems to prevent neo-aortic dilatation.

Pediatric Autograft Aortic Root Replacement: A Prospective Follow-Up Study

BACKGROUND

The autograft procedure offers children who require aortic valve replacement the advantage of an autologous valve that has growth potential and does not require anticoagulation. However, the autograft procedure is a double valve operation and its durability depends on the lifetime of both the autograft and the pulmonary valve substitute. We present our clinical experience with pediatric autograft aortic root replacement.

METHODS

Between September 1988 and September 2003, 47 children (mean age, 8 years; standard deviation, 5 years; range, 3 months to 15 years) underwent autograft aortic root replacement. Perioperative characteristics and annual follow-up information were collected prospectively.

RESULTS

The male to female ratio was 32 to 15. Eighty-nine percent of patients had congenital aortic valve disease, 47% of patients previously underwent cardiac surgery, and 43% had an aortic valve balloon dilatation. Concomitant left ventricular outflow tract enlargement was performed in 19 patients. In all cases the pulmonary valve was replaced using an allograft. There were no hospital deaths. Mean follow-up was 6.1 years (median 5.4; range, 1 month to 15 years; total of 284 patient years). During follow-up 3 patients died. Cumulative survival was 95% at 1 year and 93% at 12 years. One patient had endocarditis of the pulmonary allograft develop. Three patients required reoperation; two patients for allograft degeneration at 9.4 and 12.8 years, and 1 for combined autograft dilatation and allograft degeneration at 7.7 years postoperatively. Freedom from valve-related reoperation was 86% at 12 years.

CONCLUSIONS

Pediatric autograft aortic root replacement is associated with acceptable mortality and reoperation rates in the first decade postoperatively. It allows most children to grow into adulthood without the need for anticoagulation and additional valve replacements.

Prognosis After Aortic Valve Replacement With the Carpentier-Edwards Pericardial Valve: Use of Microsimulation

BACKGROUND

The second-generation Carpentier-Edwards pericardial valve (Edwards Lifesciences LLC, Irvine, CA) is widely used for aortic valve replacement. However, knowledge on the long-term outcomes of patients after valve implantation is incomplete. We used microsimulation to calculate the long-term outcome of any given patient after aortic valve replacement with the Carpentier-Edwards pericardial valve.

METHODS

A meta-analysis of 8 reports on aortic valve replacement with the Carpentier-Edwards pericardial valve (2,685 patients; 12,250 patient years) was used to estimate the hazards of valve-related events other than structural valvular deterioration. Structural valvular deterioration was described by age-dependent Weibull curves calculated from 18-year follow-up, premarket approval, Carpentier-Edwards pericardial primary data. These estimates provided the input data for the parameters of the microsimulation model, which was then used to calculate the outcomes of patients of different ages after valve implantation. The model estimates of survival were validated using two external data sets.

RESULTS

The Weibull analysis estimated a median time to reoperation for structural valvular deterioration ranging from 18.1 years for a 55-year-old male to 23.2 years for a 75-year-old male. For a 65-year-old male, microsimulation calculated a life expectancy and event-free life expectancy of 10.8 and 9.1 years, respectively. The lifetime risk of at least one valve-related event was 38% and that of reoperation due to structural valvular deterioration 17%, respectively, for this patient. The model estimates of survival showed good agreement with external data.

CONCLUSIONS

Microsimulation provides detailed insight into the long-term prognosis of patients after aortic valve replacement. The Carpentier-Edwards pericardial valve performs satisfactorily and offers a low lifetime risk of reoperation due to structural valvular deterioration, especially for elderly patients requiring aortic valve replacement.

Metabolic alkalosis after pediatric cardiac surgery

OBJECTIVE

To determine occurrence, causes and associated mortality of postoperative metabolic alkalosis in pediatric cardiac surgery.

METHODS

We retrospectively analyzed clinical and biochemical variables of 186 consecutive cardiac operations other than ductal ligations on children less than 2 years old during the years 1999 and 2000. Metabolic alkalosis was defined as a pH>7.48 corrected for PCO2, with a base excess > or =5 on two or more consecutive measurements during an 8h period.

RESULTS

Median age was 15 weeks [range 2 days-95 weeks] and median weight 4.5 kg [range 2.1-15.7 kg]. In 157 cases, cardiopulmonary bypass was used. In 92 [49%] procedures, metabolic alkalosis occurred with the highest corrected pH 24.3h after operation. Multivariate regression analysis associated age [P<0.001], cardiopulmonary bypass [P<0.001] and preoperative ductal dependency [P=0.04] with postoperative metabolic alkalosis. Of the surgical procedures the arterial switch for transposition of the great arteries [n=19] was strongly associated with metabolic alkalosis [100%, P<0.001]. Hemodilution appeared to enhance the development of alkalosis: those who experienced alkalosis had been hemodiluted to a greater extent [P=0.007]. Nearly 95% of patients experienced some increase in bicarbonate, but patients with metabolic alkalosis experienced more than those without [5.9 versus 3.5 mmol/l, P<0.001]. There were four postoperative deaths, only one coincidental with metabolic alkalosis.

CONCLUSIONS

Metabolic alkalosis has a high incidence after pediatric cardiac surgery, strongly associated with younger age, cardiopulmonary bypass, preoperative ductal dependency and perioperative hemodilution. Early recognition allows for timely therapeutic intervention.

Late Outcome After Stenting or Coronary Artery Bypass Surgery for the Treatment of Multivessel Disease: A Single-Center Matched-Propensity Controlled Cohort Study

BACKGROUND

Although several randomized controlled trials examined the relative benefits of coronary artery bypass graft (CABG) surgery and percutaneous coronary intervention (PCI), the most appropriate treatment remains a matter of debate, at least in some subsets of patients. Therefore, we evaluated the 8-year outcome after multivessel stent implantation (stent group) or coronary artery bypass surgery (CABG group) in a single-center propensity-matched cohort study.

METHODS

The stent study population consisted of all 409 consecutive patients who underwent an elective coronary intervention between 1995 and 1999 in whom at least 2 stents were implanted in multiple vessels. They were matched by using the propensity score method with 409 CABG patients of 1,723 CABG patients with multivessel disease who underwent elective CABG in the same period of time. The two populations were very different before matching. After matching, the CABG population resembled a stent population.

RESULTS

The cumulative survival rates after stent were 93%, 90%, and 82% at, respectively, 3, 5, and 8 years; and after CABG 97%, 93%, and 87% (p = 0.02). This was caused mainly by patients with left main disease (p = 0.03). Event-free survival was only 70%, 68%, and 64% after stent and 89%, 82%, and 78% after CABG at, respectively, 3, 5, and 8 years (p < 0.0001). After adjusting, stent was an independent predictor of higher mortality.

CONCLUSIONS

In this matched cohort study with an 8-year follow-up, survival was better and less repeat revascularizations were needed among patients undergoing elective CABG for the treatment of multivessel disease as compared with the stent group.

Survival After Pathological Stage IA Nonsmall Cell Lung Cancer: Tumor Size Matters

BACKGROUND

This study evaluates prognostic factors for survival in completely resected pathological stage IA nonsmall cell lung cancer with special emphasis on tumor size and assesses tumor recurrence rate by actual and actuarial analysis.

METHODS

From January 1989 to December 2001, 130 consecutive resections for pathological stage IA nonsmall cell lung cancer were performed. Pathological tumor size was categorized into 0 to 20 mm and 21 to 30 mm. Each patient was scaled according to the Charlson Comorbidity Index. The Kaplan-Meier method was used for estimation of actuarial recurrence rate and the cumulative incidence method was used to estimate the actual recurrence rate. Risk factors for overall and disease free survival were determined by univariate and multivariate Cox regression analysis.

RESULTS

Overall 5-year survival for patients with tumors 0 to 20 mm and 21 to 30 mm was 69% and 51%, respectively (p = 0.038). Disease-free survival at 5 years was 68% and 48%, respectively (p = 0.015). Only 27 patients had a recurrence and 69 patients died during follow-up. The actual 10-year recurrence rate was lower than the actuarial recurrence rate (23% vs 29%). Larger tumor size (relative risk 1.6; 95% confidence interval 1.0 to 2.7), Charlson Comorbidity Index score greater than or equal to 3 (relative risk 3.7; 95% confidence interval 1.7 to 8.0), and pneumonectomy (relative risk 2.1; 95% confidence interval 1.1 to 4.2) independently predicted adverse outcome.

CONCLUSIONS

Tumor size affects survival in resected stage IA nonsmall cell lung cancer. Current definition of stage IA disease should be substaged into two separate stages. In patients with early-stage lung cancer and relatively good prognosis actual recurrence rate is more realistic than the actuarial recurrence rate.

The impact of the introduction of drug-eluting stents on the clinical practice of surgical and percutaneous treatment of coronary artery disease

AIMS

Sirolimus-eluting stents (SES) have recently been shown to reduce restenosis in selected patients. The impact of this new stent on the use of coronary bypass graft (CABG) surgery or percutaneous coronary intervention (PCI) in clinical practice is yet unknown. Therefore, we investigated the impact of SES on the clinical practice of CABG and PCI in a series of unselected consecutive patients.

METHODS AND RESULTS

Between April and October 2002, a policy of SES implantation for all procedures has been instituted in our hospital. In total, 798 patients were referred to PCI and 275 to CABG (SES group). A control group was composed of all interventions (806 PCI and 314 CABG) performed during the preceding 6 months (pre-SES). The main outcome was the occurrence of major adverse cardiac events (MACE) at 15 months. In the SES era, a significant shift was noted in the PCI group towards more multi-vessel stenting (28 vs. 24%; P<0.05), more bifurcation stenting (18 vs. 7%; P<0.0001), and the use of more stents (1.9 vs. 1.5; P<0.05). In the PCI elective patients, a shift was noted towards more three-vessel disease (pre-SES: 16% vs. SES: 23%; P=0.02). Furthermore, we observed a shift in the CABG group towards more impaired LV function (pre-SES: 34% vs. SES: 41%; P=0.02) and towards more three-vessel disease (pre-SES: 67% vs. SES: 75%; P=0.03). Overall, the cumulative MACE percentages at 1 year after coronary revascularization (PCI and CABG combined) decreased from 16.8 to 13.8% (P=0.03). The cumulative MACE percentages in the pure SES group and the pre-SES bare metal stent group at 12 months were 15.6 and 19.8%, respectively (P<0.01).

CONCLUSION

The introduction of the SES has certainly had an impact on the treatment strategy of coronary artery disease (CAD). Increased use of these stents allows more complex coronary anatomy to be treated by PCI, and results in lower repeat revascularization rates.

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.

Is a bicuspid aortic valve a risk factor for adverse outcome after an autograft procedure?

BACKGROUND

Recently, bicuspid aortic valve disease is posed to be a possible risk factor for dilatation of the pulmonary autograft.

METHODS

Analysis of all 123 patients in our prospective cohort with their native aortic valve in situ at the autograft procedure.

RESULTS

The bicuspid aortic valve group (n = 81) had more males (p = 0.05), prior cardiac surgery (p = 0.02), prior aortic valve balloon dilatation (p = 0.01), aortic stenosis (p = 0.03), and less deterioration of left ventricular function (p = 0.02) than the tricuspid group (n = 42). Hospital mortality occurred in 3 patients (bicuspid 2, tricuspid 1). The follow-up was 99% complete (median, 5.3 years; SD, 3.5; range, 0.1 to 13.4) with a total of 674 patient years. During follow-up 4 patients died (bicuspid 2, tricuspid 2). Overall survival was 95% (95% confidence interval [CI], 89% to 98%) at 5 and 10 years. Seven patients required reoperation for autograft failure, all structural. Freedom from autograft reintervention was 97% (95% CI, 92% to 100%) at 5 years and 89% (95% CI, 79% to 98%) at 10 years. There were no differences in outcome between the groups. Four patients required reoperation for allograft failure, all structural. Freedom from allograft reoperation was 99% (95% CI, 97% to 100%) at 5 years and 91% (95% CI, 82% to 100%) at 10 years. There was no difference between the groups.

CONCLUSIONS

An autograft procedure in patients with a bicuspid aortic valve is justified. Bicuspid aortic valve disease is not a contraindication for an autograft procedure. Patients with a bicuspid aortic valve will meet the limitations of the autograft procedure in the same frequency as the overall autograft population.

Eosinophilic myocarditis in patients awaiting heart transplantation*

OBJECTIVE

To determine the possible causative agents of eosinophilic or hypersensitivity myocarditis in patients awaiting heart transplantation.

DESIGN

Consecutive patient series.

SETTING

Large university-affiliated hospital.

PATIENTS

A total of 190 consecutive patients who had heart transplantation at our center.

INTERVENTIONS

The myocardium of the explanted heart was examined for a mixed inflammatory cell infiltrate containing an identifiable component of eosinophils. The relative quantity of each cell type was evaluated by a semiquantitative grading system (scored 0 to 3). The clinical findings and medications were reviewed, and patients were followed after heart transplantation.

MEASUREMENTS AND MAIN RESULTS

Eosinophilic myocarditis (EM) was found in the explanted heart in 14 patients (7.4%). Myocardial infiltration by eosinophils ranged from mild (n = 6), often focal involvement to marked (n = 8), usually multifocal or widespread involvement. Twelve patients (86%) had peripheral blood eosinophilia before transplant, and in ten (71%), the eosinophil count at least doubled. Loop or thiazide diuretics were used in all 14 patients, and angiotensin-converting enzyme inhibitors were used in 12. Preoperative characteristics were similar in patients with and without EM, except for a higher frequency of inotropic support and assist devices in EM patients. Dobutamine was used in 12 (86%) and dopamine in seven (50%; one with dopamine alone), and one patient (7%) received neither dopamine nor dobutamine. In two patients receiving dobutamine and one receiving dopamine, tapering or discontinuation of the inotropic infusion resulted in a significant diminution of the peripheral eosinophilia and the EM before transplantation. Postoperative survival in patients with and without EM was similar at 8 yrs (50% +/- 13% and 54% +/- 4%, p =.34). No patient in this study has had EM on biopsy after transplant.

CONCLUSIONS

EM is a complication of multiple drug therapy in patients awaiting heart transplantation, and should be suspected when peripheral blood eosinophilia is present or the eosinophil count increases by at least two-fold. EM may be related to intravenous inotropic therapy, and this is the first study to document improvement in myocardial pathology after inotropic drug withdrawal. Hypersensitivity to thiazide and loop diuretics, angiotensin-converting enzyme inhibitors, and antibiotics must also be considered. Survival after heart transplantation is not impaired, and postoperative steroid therapy may prevent EM.

Choice of a mechanical valve or a bioprosthesis for AVR: does CABG matter?

OBJECTIVE

Mechanical valves and bioprostheses are the commonly used devices in aortic valve replacement (AVR). Many patients with valvular disease also require concomitant coronary artery bypass grafting (CABG). We used a microsimulation model to provide insight into the outcomes of patients after AVR with mechanical valves and stented bioprostheses, with and without CABG, and to determine the age-thresholds or age crossover points in outcomes between the two valve types.

METHODS

We conducted a meta-analysis of published results after primary AVR with mechanical prostheses (nine reports, 4274 patients, 25,726 patient-years) and stented porcine bioprostheses (13 reports, 9007 patients, 54,151 patient-years) to estimate risks of valve-related events. A hazard ratio of 1.3 was used to incorporate the effect of CABG on long-term survival. Estimates were entered into a microsimulation model, which was then used to predict the outcomes of patients after AVR, with and without CABG. The model calculations were validated using a large data set from Portland, USA.

RESULTS

For a 65-year-old male without CABG, the life expectancy (LE) was 11.2 and 11.6 years and the event-free life expectancy (EFLE) was 8.2 and 8.9 years, respectively, after implantation with mechanical valves and bioprostheses. The lifetime risk of at least one valve-related event was 51 and 47%, respectively. The age crossover point between the two valve types, considering the above outcome parameters, was 59, 60 and 63 years, respectively. CABG reduced LE and consequently EFLE and lifetime risk of an event, but only minimally influenced the patient age crossover points. The model calculations showed good agreement with the Portland data.

CONCLUSIONS

The currently recommended patient age for using a bioprosthesis (65 years) could be lowered further, irrespective of concomitant CABG. The trade-off between the reduced risks of bioprosthetic failure and of hemorrhage in mechanical valves, resulting from a lower LE, minimized the effect of CABG on the age crossover points between the two valve types.

Prognosis after aortic root replacement with cryopreserved allografts in adults

BACKGROUND

Aortic root replacement with cryopreserved allografts is associated with excellent hemodynamics, little endocarditis, low thromboembolic event rates, and no need for anticoagulation. There is, however, concern regarding the long-term durability of this valve substitute, especially in younger patients. Meta-analysis and microsimulation were used to calculate age-specific long-term prognosis after allograft aortic root replacement based on current evidence.

METHODS

Our center's experience with cryopreserved allograft aortic root replacement in 165 adult patients was combined in a meta-analysis with reported and individual results from four other hospitals. Using this information, the microsimulation model predicted age- and gender-specific total and reoperation-free and event-free life expectancy.

RESULTS

The pooled results comprised 629 patients with a total follow-up of 1860 patient-years (range 0 to 12.8 years). Annual risks were 0.6% for thromboembolism, 0.05% for bleeding, 0.5% for endocarditis, and 0.5% for nonstructural valve failure. Structural allograft failure requiring reoperation occurred in 15 patients, and a patient age-specific Weibull function was constructed accordingly. Calculated total life expectancy varied from 27 years in a 25-year-old to 12 years in a 65-year-old male; corresponding actual lifetime risk of reoperation was 89% and 35%, respectively.

CONCLUSIONS

Cryopreserved aortic allografts have an age-related limited durability. This results in a considerable lifetime risk of reoperation, especially in young patients. The combination of meta-analysis and microsimulation provides an appropriate tool for estimating individualized long-term outcome after aortic valve replacement and can be useful both for patient counseling and prognostic research purposes.

Decision-making in aortic valve replacement: bileaflet mechanical valves versus stented bioprostheses

BACKGROUND

Valve prosthesis selection for patients who require aortic valve replacement is dependent on several interrelated factors. Often, more than one valve type seems suitable for the individual patient and selection of a valve type may be difficult.

METHODS

The application of an evidence-based microsimulation model as an objective tool to support the choice between a bileaflet mechanical prosthesis and a stented bioprosthesis in the individual patient is described. In addition, a pilot study investigating the effect of knowledge gained by this microsimulation model on prosthetic valve choice by cardiothoracic surgeons and cardiologists is presented for two hypothetical patients.

RESULTS

After implantation of a mechanical valve, bleeding and thromboembolism are common, especially in the elderly. After implantation of a bioprosthesis, reoperation for structural failure is the most important valve-related complication, especially in younger patients. Life expectancy after aortic valve replacement is markedly reduced compared with the general Dutch age-matched population, regardless of the type of valve implanted. In the pilot study knowledge gained by the microsimulation model caused a shift in the preference towards a mechanical prosthesis in clinical experts.

CONCLUSION

Microsimulation incorporating current epidemiological data provides an objective tool to estimate prognosis for individual patients after aortic valve replacement with different valve prostheses. It may develop towards a useful clinical decision support system for valve prosthesis selection.

[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.

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.

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.

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.