Open Medicine Journal


ISSN: 1874-2203 ― Volume 4, 2017
RESEARCH ARTICLE

Contemporary Mitral Valve Surgery for Septuagenarians and Octogenarians



Yi-Wen B. Liao, Tom K.M. Wang*, Sophie Harmos, Tharumenthiran Ramanathan, Peter Ruygrok
Green Lane Cardiovascular Service, Auckland City Hospital, Auckland, New Zealand

Abstract

Background:

The increasing prevalence of degenerative and functional mitral valve disease as the population ages alongside introduction of percutaneous mitral valve interventions mandates revision of outcomes of mitral valve surgery (MVS) in elderly and high risk patients. We compared the characteristics and outcomes of octogenarians and septuagenarians undergoing MVS.

Methods:

All patients over 70 years of age having isolated MVS at Auckland City Hospital during 2005-2012 were studied and divided into 70-79 and >80 years age-groups for analysis.

Results:

There were 20 octogenarians and 81 septuagenarians studied. Apart from median age (82.0 vs. 74.0 years, P<0.001) and previous stroke (15.0% vs. 1.2%, P=0.024) respectively, there were no significant differences in pre-operative characteristics. Octogenarians however had significantly higher median EuroSCORE (4.5% vs. 3.4%, P=0.010) and STS Score (5.6 vs. 2.8%, P=0.002). Despite this, octogenarians had numerically but not statistically significantly less operative mortality (0.0% vs. 7.4%, P=0.340). One, three and five-year survivals were 100.0%, 80.0% and 70.0% for octogenarians and 91.4%, 86.4% and 73.8% septuagenarians. There was also no difference in composite and individual post-operative complications including stroke (P=0.358-1.000). The only independent predictor of operative mortality was cardiopulmonary bypass time odds ratio 1.02, 95% confidence interval 1.00-1.04, P=0.044.

Conclusion:

Although octogenarians were older with higher risk scores, they did not have increased mortality and morbidity from MVS. MVS remains a safe procedure in selected octogenarians, and other factors beyond age and risk scores such as frailty would be important in deciding the modality of mitral valve intervention in elderly patients.

Keywords: Mitral valve, Cardiac surgery, Mitral valve repair, Mitral valve replacement, Geriatrics, Risk models.


Article Information


Identifiers and Pagination:

Year: 2017
Volume: 4
First Page: 1
Last Page: 8
Publisher Id: MEDJ-4-1
DOI: 10.2174/1874220301704010001

Article History:

Received Date: 17/12/2016
Revision Received Date: 12/01/2017
Acceptance Date: 20/01/2017
Electronic publication date: 28/02/2017
Collection year: 2017

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© 2017 Liao et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


* Address correspondence to this author at the Auckland city hospital, Grafton road, Auckland 1023, New Zealand; Tel: +6493670000; E-mail: twang@adhb.govt.nz




INTRODUCTION

The world’s first successful heart valve surgery was performed in 1923 on a 12 year-old girl with rheumatic mitral stenosis, and twenty years later, John Gibbon performed the first successful open heart surgery using cardiopulmonary bypass, often considered the most important advancement in heart valve surgery [1Stoney WS. Evolution of cardiopulmonary bypass. Circulation 2009; 119(21): 2844-53.
[http://dx.doi.org/10.1161/CIRCULATIONAHA.108.830174] [PMID: 19487602]
, 2Cohn LH. Fifty years of open-heart surgery. Circulation 2003; 107(17): 2168-70.
[http://dx.doi.org/10.1161/01.CIR.0000071746.50876.E2] [PMID: 12732590]
]. Further refinements of surgical techniques, recommended for treating severe symptomatic valvular heart disease, have since been developed to meet demands of the increasing prevalence of degenerative and functional valve disease for the aging population [3Cohn LH, Tchantchaleishvili V, Rajab TK. Evolution of the concept and practice of mitral valve repair. Ann Cardiothorac Surg 2015; 4(4): 315-21.
[PMID: 26309840]
-5Nishimura RA, Otto CM, Bonow RO, et al. American College Of Cardiology/American heart association task force on practice guidelines. 2014 AHA/ACC guideline for the management of patients with valvular heart disease: A report of the American College of Cardiology/American Heart Association task force on practice guidelines. Circulation 2014; 129(23): e521-643.
[http://dx.doi.org/10.1161/CIR.0000000000000031] [PMID: 24589853]
]. Mitral valve disease is common at over 10% in those over 75 years of age [6Nkomo VT, Gardin JM, Skelton TN, Gottdiener JS, Scott CG, Enriquez-Sarano M. Burden of valvular heart diseases: a population-based study. Lancet 2006; 368(9540): 1005-11.
[http://dx.doi.org/10.1016/S0140-6736(06)69208-8] [PMID: 16980116]
, 7Nishimura RA, Vahanian A, Eleid MF, Mack MJ. Mitral valve diseasecurrent management and future challenges. Lancet 2016; 387(10025): 1324-34.
[http://dx.doi.org/10.1016/S0140-6736(16)00558-4] [PMID: 27025438]
]. Age however is an established risk factor for cardiac surgery, and part of all conventional mortality risk models to help select favourable surgical candidates [8Roques F, Michel P, Goldstone AR, Nashef SA. The logistic EuroSCORE. Eur Heart J 2003; 24(9): 881-2.
[http://dx.doi.org/10.1016/S0195-668X(02)00799-6] [PMID: 12727160]
-10OBrien SM, Shahian DM, Filardo G, et al. The society of thoracic surgeons 2008 cardiac surgery risk models: Part 2 isolated valve surgery. Ann Thorac Surg 2009; 88(1)(Suppl.): S23-42.
[http://dx.doi.org/10.1016/j.athoracsur.2009.05.056] [PMID: 19559823]
]. Due to the perceived high risk, many of these elderly patients remain untreated compared to their younger cohort [6Nkomo VT, Gardin JM, Skelton TN, Gottdiener JS, Scott CG, Enriquez-Sarano M. Burden of valvular heart diseases: a population-based study. Lancet 2006; 368(9540): 1005-11.
[http://dx.doi.org/10.1016/S0140-6736(06)69208-8] [PMID: 16980116]
, 7Nishimura RA, Vahanian A, Eleid MF, Mack MJ. Mitral valve diseasecurrent management and future challenges. Lancet 2016; 387(10025): 1324-34.
[http://dx.doi.org/10.1016/S0140-6736(16)00558-4] [PMID: 27025438]
]. The decision for intervention has also recently become more complex due to the introduction of percutaneous mitral valve techniques such as the mitraclip [11Feldman T, Foster E, Glower DD, et al. Percutaneous repair or surgery for mitral regurgitation. N Engl J Med 2011; 364(15): 1395-406.
[http://dx.doi.org/10.1056/NEJMoa1009355] [PMID: 21463154]
]. Reviewing the outcomes of mitral valve surgery (MVS) in high risk groups such as the elderly is therefore of great importance to guide clinical practice. The aim of this study is to review and compare the characteristics and outcomes of octogenarians and septuagenarians undergoing MVS.

MATERIALS AND METHODS

All patients over the age of 70 years undergoing isolated MVS at Auckland City Hospital during the period 2005-2012 were included, and grouped into 70-79 and >80 years of age for analysis. Study participants were identified retrospectively from the hospital's cardiothoracic surgical unit database. Baseline characteristics, operative variables and post-operative outcomes were retrieved from the hospital's electronic clinical records, with ethics approval attained before the study commencement from the Auckland District Health Board Research Office.

For the variables included in the study, angina class was defined according to the Canadian Cardiovascular Society grading and dyspnea class by the New York Heart Association. Other baseline characteristics followed the definitions of EuroSCORE II parameters [9Nashef SA, Roques F, Sharples LD, et al. EuroSCORE II. Eur J Cardiothorac Surg 2012; 41(4): 734-44.
[http://dx.doi.org/10.1093/ejcts/ezs043] [PMID: 22378855]
]. EuroSCORE [8Roques F, Michel P, Goldstone AR, Nashef SA. The logistic EuroSCORE. Eur Heart J 2003; 24(9): 881-2.
[http://dx.doi.org/10.1016/S0195-668X(02)00799-6] [PMID: 12727160]
], EuroSCORE II [9Nashef SA, Roques F, Sharples LD, et al. EuroSCORE II. Eur J Cardiothorac Surg 2012; 41(4): 734-44.
[http://dx.doi.org/10.1093/ejcts/ezs043] [PMID: 22378855]
] and Society of Thoracic Surgeon’s (STS) Scores [10OBrien SM, Shahian DM, Filardo G, et al. The society of thoracic surgeons 2008 cardiac surgery risk models: Part 2 isolated valve surgery. Ann Thorac Surg 2009; 88(1)(Suppl.): S23-42.
[http://dx.doi.org/10.1016/j.athoracsur.2009.05.056] [PMID: 19559823]
] were calculated for all patients.

Mortality data was obtained from the “Births, Deaths and Marriages registers” of New Zealand up till December 2015. Operative mortality was defined as in-hospital deaths or deaths within 30 days of surgery. The five post-operative complications (stroke, renal failure, ventilation >24hrs, mediastinitis and return to theatre) and their composite were defined as per the STS database [10OBrien SM, Shahian DM, Filardo G, et al. The society of thoracic surgeons 2008 cardiac surgery risk models: Part 2 isolated valve surgery. Ann Thorac Surg 2009; 88(1)(Suppl.): S23-42.
[http://dx.doi.org/10.1016/j.athoracsur.2009.05.056] [PMID: 19559823]
]. Survival rates at one, three and five-years were recorded.

Median (lower-upper quartile) and percentages (frequency) are used to present continuous and categorical variables respectively. Univariate analysis was performed using Mann- Whitney U Test and Fisher’s Exact Test for continuous and categorical variables respectively. Longitudinal survival was analysed by Kaplan-Meier curves and log-rank (Mantel-Cox) test. Area under the receiver operative characteristics curves (c-statistics) with 95% confidence intervals (95%CI) were used to assess the discriminative ability of risk scores. Variables with P<0.20 in univariate analysis were selected for multivariate analysis to identify independent predictors of various surgical outcomes. Logistic regression and Cox Proportional Hazards Regression were used for cross-sectional and longitudinal outcomes respectively. All tests were two-tailed and P<0.05 considered statistically significant. SPSS(Version 17.0, SPSS Inc., Chicago, IL, USA) and Prism (Version 5, GraphPad Software, San Diego, CA, USA) were used for statistical analyses.

RESULTS

A total of 101 patients who received isolated MVS at Auckland City Hospital from 2005-2012 were included in the study. Out of the 101 patients, 20 patients were part of the octogenarian group at time of surgery, and the remaining 81 in the septuagenarian group. Baseline characteristics are listed in Table 1. There were no significant differences in pre-operative characteristics between the two groups apart from age (median age 82 years for octogenarians and 74 years for septuagenarians, P<0.001) and previous stroke (15% in octogenarians and 1.2% septuagenarians, P=0.024). Significantly higher median scores were found in the octogenarians compared to the septuagenarians for two of three risk models: EuroSCORE(11.4% and 7.0% respectively, P=0.01) and STS score (5.6% and 2.8% respectively, P=0.02).

Table 1
Baseline characteristics.


The operative variables and in-hospital outcomes for each group are demonstrated in Table 2. There were no differences observed for operative variables measured, with approximately half of patients having mitral repair and replacement for both groups. There were also no differences in operative mortality and all complications (stroke, renal failure, ventilation >24 hours, mediastinitis and return to theatre) and their composite between the two groups. Notably none of the patients died in-hospital or within 30-days in the octogenarian group, and 6 (7.4%) died in septuagenarian group although P-value was not statistically significant at 0.596.

Table 2
Operative variables and post-operative outcomes.


Fig. (1) illustrates the survival during a mean follow-up of 5.1+/-2.6 years for both groups. One, three and five-year survivals were 100.0%, 80.0% and 70.0% for octogenarians and 91.4%, 86.4% and 73.8% septuagenarians. There was no statistically significant difference between the two groups (P=0.986).

Fig. (1)
Kaplan-Meier survival curves for octogenarians and septuagenarians undergoing mitral valve surgery.


Table 3 shows predictors of post-operative mortality and complications in multivariate analysis for the study cohort. Cardiopulmonary bypass time and age were independent predictors of operative and long-term mortality respectively; history of congestive heart failure was a predictor of composite morbidity and history of previous cardiac surgery was a predictor of return to theatre.

Table 3
Multivariate analysis (for predictors P<0.10).


Results of the discriminant analysis for risk scores at predicting outcomes are presented in Table 4. None of the risk scores were able to predict mortality and most morbidities. However, EuroSCORE could predict renal failure (AUC 0.742, 95% CI 0.576-0.906) and mediastinitis (EuroSCORE AUC 0.717, 95% CI 0.598-0.837); EuroSCORE II predicted stroke (AUC 0.722, 95%CI 0.632-0.812) and mediastinitis (AUC 0.818, 95%CI 0.742-0.894); and STS Score predicted composite morbidity (AUC 0.649, 95% CI 0.530-0.769), stroke (AUC 0.742, 95%CI 0.641-0.843) and mediastinitis (AUC 0.687, 95% CI 0.512-0.86).

Table 4
Discrimination analyses for risk scores at predicting outcomes. Area under the curve (95% confidence interval).


DISCUSSION

Mitral valve disease is the commonest form of valvular heart disease, and along with our aging population, has led to a growing demand for mitral valve intervention with many patients remaining untreated [6Nkomo VT, Gardin JM, Skelton TN, Gottdiener JS, Scott CG, Enriquez-Sarano M. Burden of valvular heart diseases: a population-based study. Lancet 2006; 368(9540): 1005-11.
[http://dx.doi.org/10.1016/S0140-6736(06)69208-8] [PMID: 16980116]
, 7Nishimura RA, Vahanian A, Eleid MF, Mack MJ. Mitral valve diseasecurrent management and future challenges. Lancet 2016; 387(10025): 1324-34.
[http://dx.doi.org/10.1016/S0140-6736(16)00558-4] [PMID: 27025438]
]. This unmet clinical need is in part due to subgroups deemed at high surgical risk, and warranting the evaluation of surgery in such patients. Our study reported favourable outcomes for isolated mitral valve surgery in carefully selected elderly patients, and these findings alongside other studies in the era of percutaneous valvular interventions have many clinical implications.

Post-operative outcomes between the two age groups were not significantly different statistically, though numerically higher operative mortality in septuagenarians compared to 0% in octogenarians. Baseline characteristics were well matched except higher prevalence of previous stroke in octogenarians. Therefore the main contributor to the higher EuroSCORE and STS Score in octogenarians was predominantly the age difference. This was a similar finding to our previous study of aortic valve replacement in elderly patients [12Wang TK, Sathananthan J, Chieng N, Gamble GD, Haydock DA, Ruygrok PN. Aortic valve replacement in over 70 and over 80-year olds: 5-year cohort study. Asian Cardiovasc Thorac Ann 2014; 22(5): 526-33.
[http://dx.doi.org/10.1177/0218492313497950] [PMID: 24867025]
], and perhaps reflect a more cautious and conservative approach in selecting octogenarians for cardiac surgery compared to younger counterparts [13Alexander KP, Anstrom KJ, Muhlbaier LH, et al. Outcomes of cardiac surgery in patients > or = 80 years: results from the National Cardiovascular Network. J Am Coll Cardiol 2000; 35(3): 731-8.
[http://dx.doi.org/10.1016/S0735-1097(99)00606-3] [PMID: 10716477]
]. However, this also reflects that when elderly patients are carefully assessed pre-operatively, excellent outcomes can be obtained. Furthermore, the risk of morbidities, many of which potentially have quality of life implications, should be considered and evaluated.

Another important strategy to improve outcome beyond pre-operative evaluation is the surgical technique employed. Mitral valve repair is superior to replacement in primary mitral valve disease, and this is true in studies of elderly patients also, in terms of short and long-term mortality and stroke, with comparable re-operation rates [14Ailawadi G, Swenson BR, Girotti ME, et al. Is mitral valve repair superior to replacement in elderly patients? Ann Thorac Surg 2008; 86(1): 77-85.
[http://dx.doi.org/10.1016/j.athoracsur.2008.03.020] [PMID: 18573402]
-17Nardi P, Pellegrino A, Olevano C, et al. Mitral valve repair for the treatment of degenerative mitral valve disease with or without prosthetic ring annuloplasty: Long-term outcomes. J Cardiovasc Surg (Torino) 2013; 54(2): 305-12.
[PMID: 23138606]
]. Mitral valve repair is therefore recommended whenever possible, and feasibility may be improved by operating earlier before extensive valvular destruction and/or advanced symptoms and instability develops, as well as surgeons’ expertise [4Vahanian A, Alfieri O, Andreotti F, et al. Guidelines on the management of valvular heart disease (version 2012). Eur Heart J 2012; 33(19): 2451-96.
[http://dx.doi.org/10.1093/eurheartj/ehs109] [PMID: 22922415]
, 5Nishimura RA, Otto CM, Bonow RO, et al. American College Of Cardiology/American heart association task force on practice guidelines. 2014 AHA/ACC guideline for the management of patients with valvular heart disease: A report of the American College of Cardiology/American Heart Association task force on practice guidelines. Circulation 2014; 129(23): e521-643.
[http://dx.doi.org/10.1161/CIR.0000000000000031] [PMID: 24589853]
, 18Ghoreishi M, Dawood MY, Gammie JS. Mitral valve surgery in elderly patients with mitral regurgitation: Repair or replacement with tissue valve? Curr Opin Cardiol 2013; 28(2): 164-9.
[http://dx.doi.org/10.1097/HCO.0b013e32835da4f8] [PMID: 23314759]
, 19Sfeir PM, Jebara VA, Ayoub CM. Mitral valve repair or replacement in elderly people. Curr Opin Anaesthesiol 2006; 19(1): 82-7.
[http://dx.doi.org/10.1097/01.aco.0000192771.79032.29] [PMID: 16547438]
]. Although we did not find mitral valve repair or replacement be independently associated with adverse outcomes, this analysis may have been limited by the power of our study.

Importantly, we found all three conventional surgical risk models were unable to discriminate operative mortality in our cohort. This is in contrast to their good performance in general isolated mitral valve surgery patients, with area under the curve of 0.67-0.89 in other studies [20Chan V, Ahrari A, Ruel M, Elmistekawy E, Hynes M, Mesana TG. Perioperative deaths after mitral valve operations may be overestimated by contemporary risk models. Ann Thorac Surg 2014; 98(2): 605-10.
[http://dx.doi.org/10.1016/j.athoracsur.2014.05.011] [PMID: 24968772]
-22Di Dedda U, Pelissero G, Agnelli B, De Vincentiis C, Castelvecchio S, Ranucci M. Accuracy, calibration and clinical performance of the new EuroSCORE II risk stratification system. Eur J Cardiothorac Surg 2013; 43(1): 27-32.
[http://dx.doi.org/10.1093/ejcts/ezs196] [PMID: 22822108]
]. This can largely be explained by high risk patients, and in some ways mitral valve surgery (compared to coronary and aortic valve operations) only constituting a small proportion of the derivation cohort for surgical risk scores [8Roques F, Michel P, Goldstone AR, Nashef SA. The logistic EuroSCORE. Eur Heart J 2003; 24(9): 881-2.
[http://dx.doi.org/10.1016/S0195-668X(02)00799-6] [PMID: 12727160]
-10OBrien SM, Shahian DM, Filardo G, et al. The society of thoracic surgeons 2008 cardiac surgery risk models: Part 2 isolated valve surgery. Ann Thorac Surg 2009; 88(1)(Suppl.): S23-42.
[http://dx.doi.org/10.1016/j.athoracsur.2009.05.056] [PMID: 19559823]
]. Prediction of complications was also poor employing these scores. There is therefore the need to assess other potentially important baseline characteristics such as functional status, cognition and the ability to respond to physiological stress ie frailty; ongoing development of newer risk models incorporating these factors to specifically address the elderly and high risk subgroups; and involvement of both the Heart Team and sound clinical judgment in decision-making for intervention.

Percutaneous mitral valve intervention techniques such as Mitraclip have been recently developed, and when compared to mitral valve surgery in high risk patients have similar operative mortality rates and improvement in symptoms, lower adverse events but increased prevalence of significant residual mitral regurgitation and need for redo procedure at up to 1 year [11Feldman T, Foster E, Glower DD, et al. Percutaneous repair or surgery for mitral regurgitation. N Engl J Med 2011; 364(15): 1395-406.
[http://dx.doi.org/10.1056/NEJMoa1009355] [PMID: 21463154]
]. Between 1 and 4 years, survival, mitral valve dysfunction and re-intervention rates are similar [23Mauri L, Foster E, Glower DD, et al. 4-year results of a randomized controlled trial of percutaneous repair versus surgery for mitral regurgitation. J Am Coll Cardiol 2013; 62(4): 317-28.
[http://dx.doi.org/10.1016/j.jacc.2013.04.030] [PMID: 23665364]
]. Combining these results and our findings, the main benefits of Mitraclip in high risk patients are lower complication rates (except residual mitral regurgitation), and shorter hospital stay and recovery time, which has both cost and quality of life implications particularly in elderly patients. More studies are required to identify important factors which assist selection of treatment modality, the prognostic utility of existing and newly developed risk models for Mitraclip in elderly patients, as well as long-term durability such percutaneous techniques.

There are several limitations to our study. The study size was limited as a single-centre study especially for the octogenarian subgroup, but reflects the real-world experience that very few of these patients undergo mitral valve surgery. It is a retrospective observational study with inherent biases, and we were unable to obtain the numbers, characteristics, outcomes and reasons for all the patients over 70 years of age with isolated mitral valve surgery being declined. The only long-term outcome we could collect was mortality, but other outcomes such as symptoms and quality of life are also important determinants of treatment efficacy. Follow-up was limited to a mean of about 5 years, given that this was a contemporary cohort.

CONCLUSION

In conclusion, MVS remains a safe procedure with acceptable mortality and morbidities rates in selected elderlies. In our cohort octogenarians were older with higher risk scores, but didn’t have excess adverse outcomes compared to septuagenarians. Further studies are required both determine what other variables beyond age and risk scores influence outcomes, and to guide selection of treatment modality for several mitral valve disease in high risk patients.

CONFLICT OF INTEREST

The authors confirm that this article content has no conflict of interest.

ACKNOWLEDGEMENTS

Declared none.

REFERENCES

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[PMID: 23138606]
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[http://dx.doi.org/10.1016/j.athoracsur.2014.05.011] [PMID: 24968772]
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Endorsements



"Open access will revolutionize 21st century knowledge work and accelerate the diffusion of ideas and evidence that support just in time learning and the evolution of thinking in a number of disciplines."


Daniel Pesut
(Indiana University School of Nursing, USA)

"It is important that students and researchers from all over the world can have easy access to relevant, high-standard and timely scientific information. This is exactly what Open Access Journals provide and this is the reason why I support this endeavor."


Jacques Descotes
(Centre Antipoison-Centre de Pharmacovigilance, France)

"Publishing research articles is the key for future scientific progress. Open Access publishing is therefore of utmost importance for wider dissemination of information, and will help serving the best interest of the scientific community."


Patrice Talaga
(UCB S.A., Belgium)

"Open access journals are a novel concept in the medical literature. They offer accessible information to a wide variety of individuals, including physicians, medical students, clinical investigators, and the general public. They are an outstanding source of medical and scientific information."


Jeffrey M. Weinberg
(St. Luke's-Roosevelt Hospital Center, USA)

"Open access journals are extremely useful for graduate students, investigators and all other interested persons to read important scientific articles and subscribe scientific journals. Indeed, the research articles span a wide range of area and of high quality. This is specially a must for researchers belonging to institutions with limited library facility and funding to subscribe scientific journals."


Debomoy K. Lahiri
(Indiana University School of Medicine, USA)

"Open access journals represent a major break-through in publishing. They provide easy access to the latest research on a wide variety of issues. Relevant and timely articles are made available in a fraction of the time taken by more conventional publishers. Articles are of uniformly high quality and written by the world's leading authorities."


Robert Looney
(Naval Postgraduate School, USA)

"Open access journals have transformed the way scientific data is published and disseminated: particularly, whilst ensuring a high quality standard and transparency in the editorial process, they have increased the access to the scientific literature by those researchers that have limited library support or that are working on small budgets."


Richard Reithinger
(Westat, USA)

"Not only do open access journals greatly improve the access to high quality information for scientists in the developing world, it also provides extra exposure for our papers."


J. Ferwerda
(University of Oxford, UK)

"Open Access 'Chemistry' Journals allow the dissemination of knowledge at your finger tips without paying for the scientific content."


Sean L. Kitson
(Almac Sciences, Northern Ireland)

"In principle, all scientific journals should have open access, as should be science itself. Open access journals are very helpful for students, researchers and the general public including people from institutions which do not have library or cannot afford to subscribe scientific journals. The articles are high standard and cover a wide area."


Hubert Wolterbeek
(Delft University of Technology, The Netherlands)

"The widest possible diffusion of information is critical for the advancement of science. In this perspective, open access journals are instrumental in fostering researches and achievements."


Alessandro Laviano
(Sapienza - University of Rome, Italy)

"Open access journals are very useful for all scientists as they can have quick information in the different fields of science."


Philippe Hernigou
(Paris University, France)

"There are many scientists who can not afford the rather expensive subscriptions to scientific journals. Open access journals offer a good alternative for free access to good quality scientific information."


Fidel Toldrá
(Instituto de Agroquimica y Tecnologia de Alimentos, Spain)

"Open access journals have become a fundamental tool for students, researchers, patients and the general public. Many people from institutions which do not have library or cannot afford to subscribe scientific journals benefit of them on a daily basis. The articles are among the best and cover most scientific areas."


M. Bendandi
(University Clinic of Navarre, Spain)

"These journals provide researchers with a platform for rapid, open access scientific communication. The articles are of high quality and broad scope."


Peter Chiba
(University of Vienna, Austria)

"Open access journals are probably one of the most important contributions to promote and diffuse science worldwide."


Jaime Sampaio
(University of Trás-os-Montes e Alto Douro, Portugal)

"Open access journals make up a new and rather revolutionary way to scientific publication. This option opens several quite interesting possibilities to disseminate openly and freely new knowledge and even to facilitate interpersonal communication among scientists."


Eduardo A. Castro
(INIFTA, Argentina)

"Open access journals are freely available online throughout the world, for you to read, download, copy, distribute, and use. The articles published in the open access journals are high quality and cover a wide range of fields."


Kenji Hashimoto
(Chiba University, Japan)

"Open Access journals offer an innovative and efficient way of publication for academics and professionals in a wide range of disciplines. The papers published are of high quality after rigorous peer review and they are Indexed in: major international databases. I read Open Access journals to keep abreast of the recent development in my field of study."


Daniel Shek
(Chinese University of Hong Kong, Hong Kong)

"It is a modern trend for publishers to establish open access journals. Researchers, faculty members, and students will be greatly benefited by the new journals of Bentham Science Publishers Ltd. in this category."


Jih Ru Hwu
(National Central University, Taiwan)


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