JTCS KCI
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Add to Personal Folders
Right arrow Download to citation manager
Right arrow Author home page(s):
Hiroyuki Kamiya
Matthias Karck
Axel Haverich
Artur Lichtenberg
Right arrow Permission Requests
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kamiya, H.
Right arrow Articles by Lichtenberg, A.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Kamiya, H.
Right arrow Articles by Lichtenberg, A.
Related Collections
Right arrow Coronary disease

J Thorac Cardiovasc Surg 2008;135:32-37
© 2008 The American Association for Thoracic Surgery

Surgery for Acquired Cardiovascular Disease

Sternal microcirculation after skeletonized versus pedicled harvesting of the internal thoracic artery: A randomized study

Hiroyuki Kamiya, MDa, Payam Akhyari, MDa, Andreas Martens, MDb, Matthias Karck, MDa, Axel Haverich, MDb, Artur Lichtenberg, MDa,*

a Department of Cardiovascular Surgery, University of Heidelberg, Heidelberg, Germany
b Department of Cardiac, Thoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany.

Received for publication April 5, 2007; revisions received August 29, 2007; accepted for publication September 11, 2007.

* Address for reprints: Artur Lichtenberg, MD, Department of Cardiac Surgery, University of Heidelberg, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany. (Email: artur.lichtenberg{at}med.uni-heidelberg.de).


   Abstract
Top
 Abstract
Introduction
 Materials and Methods
 Results
 Discussion
 References
 
Objective: In human patients the influence of skeletonized internal thoracic artery harvesting on the sternal microcirculation in the perioperative phase has not been well investigated.

Methods: Twenty-four consecutive male patients who were scheduled for isolated coronary artery bypass grafting were prospectively randomized into 2 groups. The left internal thoracic artery was harvested by using the skeletonized technique in group 1, and it was harvested with a pedicle in group 2. Superficial (2 mm) and deep (8 mm) tissue oxygen saturation and blood flow were measured presternally and retrosternally in the upper, middle, and lower sternal parts with a novel laser Doppler flowmetric and remission spectroscopic system (Oxygen-to-See; LEA Medizintechnik, Giessen, Germany).

Results: Presternal tissue oxygen saturation deteriorated at the upper and middle sternum, and presternal blood flow deteriorated at all measurement points after internal thoracic artery harvesting in both groups. Skeletonization had no advantage in maintaining presternal microcirculation. Retrosternal microcirculation also deteriorated at all measurement points after internal thoracic artery harvesting in both groups. However, the deterioration of the retrosternal microcirculation was significantly less in group 1 at the middle and lower sternum; values of oxygen saturation to the baseline were 86% ± 3.8% versus 60% ± 4.3% (P = .001) at 2-mm depth and 82% ± 4.2% versus 61% ± 6.1% (P = .009) at 8-mm depth at the middle sternum and 95% ± 3.2% versus 78% ± 1.3% (P = .001) at 2-mm depth and 94% ± 2.2% versus 78% ± 4.6% (P = .004) at 8-mm depth at the lower sternum in groups 1 and 2, respectively.

Conclusion: The damage of the tissue microcirculation in the middle and lower retrosternal area is significantly less after internal thoracic artery skeletonization compared with that after the pedicled internal thoracic artery harvesting technique.

Abbreviations and Acronyms ITA = internal thoracic artery; LITA = left internal thoracic artery; SO 2 = oxygen saturation


   Introduction
Top
 Abstract
 Introduction
Materials and Methods
 Results
 Discussion
 References
 

Figure 1
Drs Lichtenberg, Akhyari, Kamiya, and Karck (left to right)


Several studies have demonstrated that the use of the left and bilateral internal thoracic artery (ITA) for coronary revascularization was a major risk factor for sternal wound infections, especially after bilateral ITA harvesting.1-3Go Previous animal and clinical studies have demonstrated that skeletonized ITA harvesting improves the blood supply to the sternum4-6Go and thus might reduce the incidence of postoperative sternal infections and morbidity, especially in patients with additional risks for sternal wound complications. However, in human subjects the influence of the skeletonized ITA harvesting method on the microcirculation of the sternum in the perioperative phase has not been investigated because of technical difficulties.

A novel laser Doppler flowmetric and remission spectroscopic system (Oxygen-to-See; LEA Medizintechnik, Giessen, Germany) enables an exact, direct, continuous, quantitative noninvasive evaluation of real-time parameters of tissue microcirculation in vivo with high time resolution and low costs.7,8Go The aim of this study was to evaluate the influence of the skeletonized ITA-harvesting technique on the sternal microcirculation compared with the pedicled ITA-harvesting technique in a randomized study cohort.


   Materials and Methods
Top
 Abstract
 Introduction
 Materials and Methods
Results
 Discussion
 References
 
Twenty-four consecutive male patients who were scheduled for isolated coronary artery bypass grafting were enrolled in the study. The patients were prospectively randomized into 2 groups. In group 1 (12 patients; age, 62.3 ± 8.4 years) the left ITA (LITA) was harvested by using the skeletonized technique with mobilizing of the artery only. Group 2 consisted of 12 patients (age, 60.9 ± 7.6) who underwent LITA harvesting with a pedicle that included the tissue around the artery, accompanying veins, and a portion of the parietal pleura. Exclusion criteria in our investigation were diabetes; diseases, deformation, or both of the sternal bone; obesity (body mass index >30 kg/m2); low ventricular function with an ejection fraction of less than 40%; New York Heart Association class III and IV; dialysis; female sex; and emergency or redo procedures. Only male patients were included in the present study to minimize study variables. The review board of our institute approved this prospective randomized study, and informed consent was obtained from all patients.

Baseline and in-hospital data were collected from each patient. Baseline characteristics included age, body mass index, left ventricular ejection fraction, cardiac risk factors (eg, smoking status), hypertension, and hyperlipidemia. Operative data included ITA harvest time, number of grafts, crossclamp time, and operative time. During intraoperative measurements, the systemic blood pressure was continuously recorded. In the postoperative observation period, intubation time; time to hospital discharge; incidence of deep, superficial, or both sternal wound infections; myocardial infarction; and in-hospital mortality were recorded.

Measurement Protocol
The median sternotomy was performed in a conventional fashion. Immediately after median sternotomy, the probe was sequentially placed presternally and retrosternally in the upper, middle, and lower sternal part for measurements of superficial (2 mm) and deep (8 mm) tissue oxygen saturation (SO 2) and blood flow (Figure 1, A).


Figure 1
View larger version (122K):
[in this window]
[in a new window]

  		Figure 1. Measurement of microcirculation parameters of the sternum (oxygen saturation and blood flow) at the presternal and retrosternal sides (A) in the upper, middle, and lower parts (arrows) by using a special probe of the laser Doppler flowmetric and remission spectroscopic system (B).

 
For the measurements, the Oxygen-to-See system, a novel laser Doppler flowmetry and remission spectroscopic system (LEA Medizintechnik) was used in this study (Figure 1, B). This equipment enables the measurement of both tissue blood flow by means of laser Doppler spectroscopy and tissue SO 2 and hemoglobin concentration by means of white-light spectrometric techniques. The mechanism was described in detail in our previous study that used this technique.7,8Go

The LITA was dissected in both groups in full length from its cranial origin to the bifurcation. Side branches were cut by using standard techniques with low-energy electrocautery, titan clipping, or both in both groups. The pedicled LITA was harvested with an approximately 2-cm-wide pedicle, including the parietal pleura, accompanying veins, and surrounding tissue. In the skeletonized group only the artery was mobilized. Before clamping the distal part of the ITA, the patient received 300 IE heparin/kg body weight intravenously.

Statistics
The data are presented as means ± standard error of the mean for continuous variables or numbers and percentages for dichotomous variables. Univariate analysis of categorical data was carried out by using the {chi}2 and Fisher exact tests. Changing value of SO 2 and blood flow after ITA harvesting to baseline were compared by using paired t tests. Baseline and percentage values of SO 2 and blood flow of the 2 groups were compared by using unpaired t tests. The SPSS statistical software package 11.0 for Windows (SPSS, Inc, Chicago, Ill) was used for statistical analysis.


   Results
Top
 Abstract
 Introduction
 Materials and Methods
 Results
Discussion
 References
 
Demographic data and baseline characteristics of studied patients are listed in Table 1. There were no significant differences between the 2 groups. Table 2 shows the intraoperative and postoperative variables. The harvesting duration was significantly longer in group 1 compared with that in group 2 (P = .003); however, there were no statistical differences in operative time or postoperative ventilation time. Serious complications did not occur, and length of hospital stay was similar in both groups.


View this table:
[in this window]
[in a new window]

  		TABLE 1 Baseline characteristics of the patients
 

View this table:
[in this window]
[in a new window]

  		TABLE 2 Operative and hospital stay characteristics of the patients
 
Sternal Tissue SO 2
Baseline presternal and retrosternal SO 2 was measured on the left sternal part, and the results are listed in Table 3. There were no significant differences in baseline values between the 2 groups. After ITA preparation, SO 2 decreased significantly at the presternal side in both groups, except for the lower sternum. At the retrosternal side, the decrease of SO 2 in group 1 at the middle sternal part was significant in both depths and at the lower sternum only at the 8-mm measurement point. On the other hand, the SO 2 parameters at the retrosternal side in both depths decreased significantly at any measurement point in group 2.


View this table:
[in this window]
[in a new window]

  		TABLE 3 Oxygen saturation
 
Percentage value of SO 2 to the baseline value was compared at each measurement point, and the results are demonstrated in Figures 2 and 3. Go At the presternal side, there was no difference between the 2 groups at any measurement point. At the retrosternal side, however, the decrease in SO 2 was not significant at the upper sternum in both groups and significantly greater at the middle and lower sternum in group 2 than it was in group 1.


Figure 2
View larger version (19K):
[in this window]
[in a new window]

  		Figure 2. Tissue oxygen saturation (SO2) of the sternum at the presternal side. White column, Group 1 (skeletonized); gray column, group 2 (pedicled).

 

Figure 3
View larger version (20K):
[in this window]
[in a new window]

  		Figure 3. Tissue oxygen saturation (SO2) of the sternum at the retrosternal side. White column, Group 1 (skeletonized); gray column, group 2 (pedicled).

 
Sternal Blood Flow
The sternal blood flow significantly decreased at both sides in both groups (Table 4). The percentage value of post–ITA harvest sternal blood flow to the baseline value is demonstrated in Figures 4 and 5. Go At the presternal side, there was no difference between the 2 groups at any measurement point, except for the 8-mm depth presternally at the upper sternum. At the retrosternal side, however, the decrease of sternal blood flow was significantly greater at the middle and lower sternum in group 2 than it was in group 1, as similar to SO 2 measurements.


View this table:
[in this window]
[in a new window]

  		TABLE 4 Blood flow
 

Figure 4
View larger version (18K):
[in this window]
[in a new window]

  		Figure 4. Blood flow of the sternum at the presternal side. White column, Group 1 (skeletonized); gray column, group 2 (pedicled).

 

Figure 5
View larger version (18K):
[in this window]
[in a new window]

  		Figure 5. Blood flow of the sternum at the retrosternal side. White column, Group 1 (skeletonized); gray column, group 2 (pedicled).

 

   Discussion
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
References
 
The crucial findings of our study are as follows. First, presternal tissue SO 2 deteriorated at the upper and middle sternum, and presternal blood flow deteriorated at all measurement points after ITA harvesting with both techniques (skeletonized and pedicled). Skeletonization had no advantage in maintaining presternal microcirculation. Second, retrosternal microcirculation deteriorated at all measurement points after ITA harvesting with both techniques. However, the deterioration of the retrosternal microcirculation was significantly less with the skeletonized ITA at the middle and lower sternum.

The use of the LITA for coronary revascularization has been recognized as mandatory because of its excellent long-term graft patency,9Go and the use of both ITAs has been suggested to have an advantage in terms of patient long-term survival over the single-ITA strategy.10Go However, it has also been well known that the use of double ITAs can worsen the sternal microcirculation and therefore cause postoperative mediastinitis with a significantly higher rate compared with that seen with the single ITA strategy.1-3Go Some study groups have advocated that the risk of postoperative mediastinitis after the use of double ITAs can be minimized with the skeletonized harvesting technique because it has a great advantage in the preservation of the sternal microcirculation over conventional pedicle techniques.11-13Go Nevertheless, the influence of ITA-harvesting techniques on sternal microcirculation in human subjects has not been studied enough because of absence of adequate measurement methods in the past.

In a canine model, Parish and colleagues6Go demonstrated that a minimized retrosternal tissue mobilization by means of skeletonized harvesting of the ITA was associated with a significantly greater residual retrosternal blood flow compared with that of the conventional pedicle preparation technique performed on the corresponding ITA on the other side. Moreover, Fokin and associates14Go investigated sternal microcirculation with a thermographic camera in a swine model and demonstrated that skeletonized and semiskeletonized ITA-harvesting techniques caused a similar acute reduction in sternal perfusion during the early postoperative period, and this effect lasted for at least 5 hours. In human subjects Cohen and coworkers4Go studied sternal vascularity using single photon emission computed tomography after ITA harvesting in detail. In their randomized study bone single photon emission computed tomography was performed during 4 to 9 days after the operation to evaluate the sternal vascularity. They found that the sternal blood flow decreased only when the LITA was harvested as a pedicle and that it was maintained with the skeletonized harvesting.

In short, the greatest limitation of previous studies is that the human sternal microcirculation in the perioperative phase has remained unclear, especially from the aspect of tissue oxygenation. Generally, wound healing is possible only through restoration of the microcirculation and the nutrition to the tissue, and because the main component of the nutrition is oxygen, local hypoxia results in delayed healing and increased risk of infection.15Go To our knowledge, the present study is the first to demonstrate the sternal microcirculation including the tissue oxygenation in the acute phase after ITA harvesting in regard to skeletonized technique.

Interestingly, some discrepancies between the decrease of the tissue SO 2 and of the blood flow were observed in the present study. Although blood flow decreased at almost all measurement points with both techniques, the tissue SO 2 did not decrease at the lower sternum on the presternal side with either technique, and the decrease of tissue SO 2 at the lower sternum on the retrosternal side was not significant with the skeletonized technique, as shown in Tables 3 and 4. These findings might have resulted from the collateral flow from the inferior epigastric artery. However, the clinical implications of these discrepancies remain unclear.

One of the major findings in the present study was that skeletonization had no advantage in preserving the presternal microcirculation, whereas the deterioration of the retrosternal microcirculation was significantly less with the skeletonized technique. This finding fits with published risk factor analyses, except for showing slightly distinct risk factors for superficial and deep sternal wound infections.12,16Go Pevni and colleagues16Go demonstrated that the use of the skeletonized bilateral ITA was predictive for deep, but not superficial, sternal wound infections, whereas obesity and an age of greater than 75 years were mainly predictive for superficial sternal infections. De Paulis and associates12Go analyzed the effect of bilateral ITA harvesting on superficial and deep sternal infections, and they found a slightly lower odds ratio for superficial sternal infection than for deep sternal infection. The technique of artery harvesting was an independent predictor for deep sternal infection, with an odds ratio of 4.1 (95% confidence interval, 1.4–12.1), whereas it was an independent predictor of superficial sternal infection, with an odds ratio of 3.0 (95% confidence interval, 1.6–5.4). The findings of our present study and the clinical results of previous relative large studies suggest that skeletonized ITA harvesting can reduce the risk of deep sternal infection.

In conclusion, skeletonization had no advantage in maintaining presternal microcirculation, whereas the deterioration of the retrosternal microcirculation was significantly less when the skeletonized technique was used. Although there was no clinical difference in infection rates between study groups because of the small study cohort, our results might suggest that the skeletonized ITA harvesting can reduce the risk of deep sternal infection.


   References
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 

  1. El OR, Paul E, Wong PS, et al. Mediastinitis in patients undergoing cardiopulmonary bypass: risk analysis and midterm results. J Cardiovasc Surg (Torino) 1997;38:595-600.[Medline]
  2. Kohli M, Yuan L, Escobar M, et al. A risk index for sternal surgical wound infection after cardiovascular surgery. Infect Control Hosp Epidemiol. 2003;24:17-25.[Medline]
  3. Grossi EA, Esposito R, Harris LJ, et al. Sternal wound infections and use of internal mammary artery grafts. J Thorac Cardiovasc Surg. 1991;102:342-346.[Abstract]
  4. Cohen AJ, Lockman J, Lorberboym M, et al. Assessment of sternal vascularity with single photon emission computed tomography after harvesting of the internal thoracic artery. J Thorac Cardiovasc Surg. 1999;118:496-502.[Abstract/Free Full Text]
  5. Lorberboym M, Medalion B, Bder O, et al. 99mTc-MDP bone SPECT for the evaluation of sternal ischaemia following internal mammary artery dissection. Nucl Med Commun. 2002;23:47-52.[Medline]
  6. Parish MA, Asai T, Grossi EA, et al. The effects of different techniques of internal mammary artery harvesting on sternal blood flow. J Thorac Cardiovasc Surg. 1992;104:1303-1307.[Abstract]
  7. Knobloch K, Lichtenberg A, Pichlmaier M, et al. Microcirculation of the sternum following harvesting of the left internal mammary artery. Thorac Cardiovasc Surg. 2003;51:255-259.[Medline]
  8. Knobloch K, Lichtenberg A, Pichlmaier M, Tomaszek S, Krug A, Haverich A. Palmar microcirculation after harvesting of the radial artery in coronary revascularization. Ann Thorac Surg. 2005;79:1026-1030.[Abstract/Free Full Text]
  9. Boylan MJ, Lytle BW, Loop FD, et al. Surgical treatment of isolated left anterior descending coronary stenosis. Comparison of left internal mammary artery and venous autograft at 18 to 20 years of follow-up. J Thorac Cardiovasc Surg. 1994;107:657-662.[Abstract/Free Full Text]
  10. Lytle BW, Blackstone EH, Loop FD, et al. Two internal thoracic artery grafts are better than one. J Thorac Cardiovasc Surg 1999;117:855-872.[Abstract/Free Full Text]
  11. Peterson MD, Borger MA, Rao V, Peniston CM, Feindel CM. Skeletonization of bilateral internal thoracic artery grafts lowers the risk of sternal infection in patients with diabetes. J Thorac Cardiovasc Surg. 2003;126:1314-1319.[Abstract/Free Full Text]
  12. De Paulis R, de Notaris S, Scaffa R, et al. The effect of bilateral internal thoracic artery harvesting on superficial and deep sternal infection: the role of skeletonization. J Thorac Cardiovasc Surg. 2005;129:536-543.[Abstract/Free Full Text]
  13. Bical OM, Khoury W, Fromes Y, et al. Routine use of bilateral skeletonized internal thoracic artery grafts in middle-aged diabetic patients. Ann Thorac Surg. 2004;78:2050-2053.[Abstract/Free Full Text]
  14. Fokin AA, Robicsek F, Fokin Jr A, Anderson Jr JE. Changes in sternal blood flow after different methods of internal thoracic artery harvesting. Thorac Cardiovasc Surg. 2004;52:334-337.[Medline]
  15. Gottrup F. Oxygen in wound healing and infection. World J Surg. 2004;28:312-315.[Medline]
  16. Pevni D, Mohr R, Lev-Run O, Locer C, Paz Y, Kramer A, Shapira I. Influence of bilateral skeletonized harvesting on occurrence of deep sternal wound infection in 1000 consecutive patients undergoing bilateral internal thoracic artery grafting. Ann Surg. 2003;237:277-280.[Medline]



This article has been cited by other articles:


Home page
 Ann. Thorac. Surg.Home page
T. Kinoshita, T. Asai, T. Suzuki, S. Kuroyanagi, S. Hosoba, and N. Takashima
Off-pump Bilateral Skeletonized Internal Thoracic Artery Grafting in Elderly Patients
Ann. Thorac. Surg., February 1, 2012; 93(2): 531 - 536.
[Abstract] [Full Text] [PDF]

Home page
 Ann. Thorac. Surg.Home page
X. Hu and Q. Zhao
Skeletonized Internal Thoracic Artery Harvest Improves Prognosis in High-Risk Population After Coronary Artery Bypass Surgery for Good Quality Grafts
Ann. Thorac. Surg., July 1, 2011; 92(1): 48 - 58.
[Abstract] [Full Text] [PDF]

Home page
 Eur J Cardiothorac SurgHome page
H. Nishi, M. Mitsuno, H. Tanaka, M. Ryomoto, S. Fukui, and Y. Miyamoto
Decreasing sternum microcirculation after harvesting the internal thoracic artery
Eur J Cardiothorac Surg, July 1, 2011; 40(1): 240 - 244.
[Abstract] [Full Text] [PDF]

Home page
 Ann. Thorac. Surg.Home page
V. Mannacio, L. Di Tommaso, V. De Amicis, P. Stassano, and C. Vosa
Randomized Flow Capacity Comparison of Skeletonized and Pedicled Left Internal Mammary Artery
Ann. Thorac. Surg., January 1, 2011; 91(1): 24 - 30.
[Abstract] [Full Text] [PDF]

Home page
 Eur Heart JHome page
D. P. Taggart, D. G. Altman, A. M. Gray, B. Lees, F. Nugara, L.-M. Yu, H. Campbell, M. Flather, and on behalf of the ART Investigators
Randomized trial to compare bilateral vs. single internal mammary coronary artery bypass grafting: 1-year results of the Arterial Revascularisation Trial (ART)
Eur. Heart J., October 2, 2010; 31(20): 2470 - 2481.
[Abstract] [Full Text] [PDF]

Home page
 J. Thorac. Cardiovasc. Surg.Home page
P. L. Markman, M. A. Rowland, J.-Y. Leong, J. Van Der Merwe, E. Storey, S. Marasco, J. Negri, M. Bailey, and F. L. Rosenfeldt
Skeletonized internal thoracic artery harvesting reduces chest wall dysesthesia after coronary bypass surgery
J. Thorac. Cardiovasc. Surg., March 1, 2010; 139(3): 674 - 679.
[Abstract] [Full Text] [PDF]

Home page
 Ann. Thorac. Surg.Home page
S. Saso, D. James, J. A. Vecht, E. Kidher, J. Kokotsakis, V. Malinovski, C. Rao, A. Darzi, J. R. Anderson, and T. Athanasiou
Effect of Skeletonization of the Internal Thoracic Artery for Coronary Revascularization on the Incidence of Sternal Wound Infection
Ann. Thorac. Surg., February 1, 2010; 89(2): 661 - 670.
[Abstract] [Full Text] [PDF]

Home page
 Interact CardioVasc Thorac SurgHome page
K. Knobloch, P. M. Vogt, and A. Lichtenberg
eComment: Sternal microcirculation following pedicled or skeletonized internal thoracic artery harvesting
Interact CardioVasc Thorac Surg, January 1, 2010; 10(1): 104 - 104.
[Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Add to Personal Folders
Right arrow Download to citation manager
Right arrow Author home page(s):
Hiroyuki Kamiya
Matthias Karck
Axel Haverich
Artur Lichtenberg
Right arrow Permission Requests
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kamiya, H.
Right arrow Articles by Lichtenberg, A.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Kamiya, H.
Right arrow Articles by Lichtenberg, A.
Related Collections
Right arrow Coronary disease

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
ANN THORAC SURG ASIAN CARDIOVASC THORAC ANN EUR J CARDIOTHORAC SURG
J THORAC CARDIOVASC SURG ICVTS ALL CTSNet JOURNALS