Reply by the Authors of the Original Article

We thank the authors for their comments on our article titled “The Preventive Effects of Posterior Pericardiotomy with Intrapericardial Tube on the Development of Pericardial Effusion (PE), Atrial Fibrillation (AF), and Acute Kidney Injury (AKI) after Coronary Artery Surgery.” We appreciate their interest and would like to answer their concerns, which requires explanations as follows.

First of all, we would like to accentuate that many adverse events such as PE, cardiac tamponade, AF, and AKI may be interwoven in the postoperative period as we emphasized in our article. Accordingly, we cited an article by Kaleda et al in the “Introduction” section for relation between PE, AF, and AKI. However, this article is a best evidence topic. When we read this article's fifth reference, which we did not cite for this association, we could find information about this relation. In addition to this, we covered nearly half of the anterior surface of the heart with pericardium and thymic tissue. Namely, the rest of heart surfaces may have seen like a sort of intact pericardium. In parallel with this information, PE from any cause may lead to low cardiac output syndrome causing decreased renal blood flow.[1] After all, Ashikhmina et al reported that oliguria was found in 12% of the patients as one of the symptoms and signs of PE after cardiac surgery. Therefore, PE should be included in the list of prerenal causes of AKI.[2]

Second, our diagnostic criteria for detecting presence of symptoms were patient's clinical signs such as tachycardia, arterial hypotension, jugular venous distension, shortness of breath, and cool and clammy skin.[3]

Regarding chest tube drainage, all chest tubes were removed routinely on the second postoperative day. But when the total drainage was not under 20 mL in 4 hours, we prolonged the drainage for 12 hours. There was no patient whose chest tube remained until the third postoperative day. The reason of echocardiographic follow-up on the second postoperative day was to be able to investigate in detail the relationship between the groups as reported in many studies.

No statistically significant differences in the classification of PE in view of the patients with greater than small PE were found between the groups during the postoperative period. The drainage of the patients treated with nonsteroid anti-inflammatory drugs and diuretics was similar between the groups in our study. For this reason, the usage of these drugs may not create bias.

In our article, the measurement scale was meant to be millimeter not milliliter as it has been published. We think that this was our typographic error resulting in such misunderstandings considering that the two dimensional echocardiography measurements that we used can only provide linear measurements (mm or cm) not three-dimensional measurements (mL or L).

We demonstrated that the rate of cardiac tamponade and AF is lower in the study group. In addition, these results have been shown in many articles in the literature. But above all, we performed first the pericardial hole technique as an adjunctive treatment modality in preventing PE and cardiac tamponade. Apart from that, AKI already can appear as a complication of AF. The techniques we applied may also decrease the rate of AF and amount of PE. Additionally, if the cardiac output in patients had been measured, we would probably have seen more reasons as to why there was a statistically significant difference between the groups in terms of kidney function. In conclusion, our approach may provide a contribution in reducing the risk of developing AKI during the postoperative period.

• References

• 1 Gluck N, Fried M, Porat R. Acute renal failure as the presenting symptom of pericardial effusion. Intern Med 2011; 50 (7) 719-721
• 2 Ashikhmina EA, Schaff HV, Sinak LJ , et al. Pericardial effusion after cardiac surgery: risk factors, patient profiles, and contemporary management. Ann Thorac Surg 2010; 89 (1) 112-118
• 3 Sagristà-Sauleda J, Mercé AS, Soler-Soler J. Diagnosis and management of pericardial effusion. World J Cardiol 2011; 3 (5) 135-143