Nebivolol compared with metoprolol for erectile function in males undergoing coronary artery bypass graft/Author's Reply

To the Editor,

I have read the article entitled "Nebivolol compared with metoprolol for erectile function in males undergoing coronary artery bypass graft" by Aldemir et al. (1) with great interest, which was recently published in Anatolian Journal of Cardiology 2016; 16: 131-6. The investigators reported that nebivolol had a protective effect on the sexual activity of men undergoing coronary artery bypass surgery with cardiopulmonary bypass (1). Brixius et al. (2) have demonstrated beneficial effects of nebivolol on the erectile function in hypertensive men. Another study revealed that serum asymmetrical dimethylarginine, prolactin, testosterone, and hemoglobin levels may affect erectile function in patients with chronic kidney disease (3). Hormonal causes such as hypogonadism, thyroid dysfunction, and hyperprolactinemia may result in ED (4). The prevalence of ED increases with age, ranging from 1% to 10% men aged ≤40 years, 20% to 40% men aged 60-69 years, and 50% to 100% men in their 70s and 80s (5).

I would like to emphasize some important points to clarify the findings of this article. First serum hemoglobin, prolactin, thyroid function tests, and testosterone levels are important factors in erectile function (4). Therefore, authors should mention patients' hemoglobin, testosterone, thyroid function tests, and prolactin levels along with whether patients with anemia and thyroid dysfunction were excluded. Second, there was no data regarding blood pressure and heart rate after initiating the beta-blocker treatment. The mean ejection fraction of patients in the metoprolol and nebivolol groups was 51.6% and 48.7%, respectively. Considering that the patients had heart failure and were on betablocker treatment, did they adjust beta-blocker doses according to blood pressure and heart rate? Third, the prevalance of ED is 50% to 100% men in 70s and 80s (5). They should have reported the number of patients over the age of 70 years because of the high incidence of erectil dysfunction. In addition, the exclusion of patients over the age of 70 years should be considered.

In conclusion, ED is more common in men with cardiovascular disease. Nebivolol seems to have benefical effects on ED. Nebivolol is a reasonable beta-blocker option for men with cardiovascular disease. However, further prospective, randomized, placebo-controlled studies are needed to confirm the benefical effect of nebivolol on ED.

References

1. Aldemir M, Keles I, Karalar M, Tecer E, Adali F, Pektas MB, et al. Nebivolol compared with metoprolol for erectile function in males undergoing coronary artery bypass graft. Anatol J Cardiol 2016; 16: 131-6.

2. Brixius K, Middeke M, Lichtenthal A, Jahn E, Schwinger RH. Nitric oxide, erectile dysfunction and beta-blocker treatment (MR NOED study): benefit of nebivolol versus metoprolol in hypertensive men. Clin Exp Pharmacol Physiol 2007; 34: 327-31. [Crossref]

3. Gökçen K, Kiliçarslan H, Coskun B, Ersoy A, Kaygisiz O, Kordan Y. Effect of ADMA levels on severity of erectile dysfunction in chronic kidney disease and other risk factors. Can Urol Assoc J 2016; 10: 41-5. [Crossref]

4. Hatzimouratidis K, Amar E, Eardley I, Giuliano F, Hatzichristou D, Montorsi F, et al. European Association of Urology, authors. Guidelines on male sexual dysfunction: erectile dysfunction and premature ejaculation. Eur Urol 2010; 57: 804-14. [Crossref]

5. Lewis RW, Fugl-Meyer KS, Corona G, Hayes RD, Laumann EO, Moreira ED Jr, et al. Definitions/epidemiology/risk factors for sexual dysfunction. J Sex Med 2010; 7: 1598-607. [Crossref]

Levent Cerit

Department of Cardiology, Near East University, Nicosia-Cyprus

Address for Correspondence: Dr. Levent Cerit

Near East Hospital University Hospital, Nicosia-Turkish Republic of Northern Cyprus

Phone: [phone]

E-mail: [email protected]

©Copyright 2016 by Turkish Society of Cardiology - Available online at www.anatoljcardiol.com

DOI:10.14744/AnatolJCardiol.2016.7121

Author`s Reply

To the Editor,

First of all, we would like to thank the authors of the letter for contributing valuable comments to our article "Nebivolol compared with metoprolol for erectile function in males undergoing coronary artery bypass graft" published in the February issue of the Anatol J Cardiol 2016; 16: 131-6. (1). Erectile dysfunction is defined as the persistent inability to attain and maintain an erection sufficient to permit satisfactory sexual performance (2). Massachusetts Male Aging Study reported an overall prevalence of 52% ED in men aged 40-70 years (3). The prevalence of ED increases with age. Wagle et al. (4) reported that ED in the ≥70 year age group was 77% and 61% in the 40 to 69 years. Until recently, ED has been accepted as psychologybased and to be a 75% organic-based disease (5). Organic-based ED may be vasculogenic, neurogenic, anatomical, and hormonal (2).

We agree with the comment that some laboratory tests should be performed as mentioned by the authors of the letter. According to the European Association of Urology Guidelines on male sexual dysfunction routine laboratory tests, glucose-lipid profile and total testosterone are required to identify and treat any reversible risk factors and modifiable lifestyle factors. Additional hormonal tests such as the estimation of prolactin and luteinizing hormone levels should be performed if low testosterone levels are detected (2). In our study we searched the lipid profile of the patients and no difference was observed between the groups. Hb and glucose levels of all patients were recorded but not compared between the groups and were not mentioned in the study. Testosterone levels were not evaluated.

The authors of the letter have proposed the exclusion of patients over the age of 70 years. In our study, mean age of the patients were 60.6±10.6 and 58.8±11.6, respectively, and there were no statistically significant differences between the two groups (p=0.61). Thus, we believe that the exclusion of patients over the age of 70 years is not essential.

The authors of the letter have questioned about the adjustment of the beta-blocker doses. Unfortunately, we did not adjust beta-blocker doses according to the blood pressure and heart rates. We used the routine doses of 5 mg/day oral nebivolol and 50 mg/day metoprolol succinate.

These valid issues noticed by the authors of the letter could be mentioned as our study limitations. We hope that our study can be a modest model for new comprehensive ones.

We thank the authors of the letter again for their great contribution to our work.

References

1. Aldemir M, Keles I, Karalar M, Tecer E, Adali F, Pektas MB, et al. Nebivolol compared with metoprolol for erectile function in males undergoing coronary artery bypass graft. Anatol J Cardiol 2016; 16: 131-6.

2. Hatzimouratidis K, Amar E, Eardley I, Giuliano F, Hatzichristou D, Montorsi F, et al; European Association of Urology. Guidelines on male sexual dysfunction: erectile dysfunction and premature ejaculation. Eur Urol 2010; 57: 804-14. [Crossref]

3. Feldman HA, Goldstein I, Hatzichristou DG, Krane RJ, MsKinlay JB. Impotence and its medical and psychosocial correlates: results of the Massachusetts Male Aging Study. J Urol 1994; 151: 54-61.

4. Wagle KC, Carrejo MH, Tan RS. The implications of increasing age on erectile dysfunction. Am J Mens Health 2012; 6: 273-9.

5. Nehra A, Barret DM, Morelan RB. Pharmacotherapeutic advances in the treatment of erectile dysfunction. Mayo Clin Proc 1999; 74: 709-21. [Crossref]

Mustafa Karalar, Mustafa Aldemir

Department of Cardiovascular Surgery, Faculty of Medicine, Afyon Kocatepe University, Afyonkarahisar-Turkey

Address for Correspondence: Dr. Mustafa Aldemir

Afyon Kocatepe Üniversitesi Tip Fakültesi Ali Çetinkaya Kampüsü, Afyonkarahisar - Izmir Karayolu 8.km PK: 03200, Afyonkarahisar-Türkiye

Phone: [phone] Fax: [phone]

E-mail: [email protected]