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Ann Thorac Surg 2007;84:67-72
© 2007 The Society of Thoracic Surgeons

Original Articles: Cardiovascular

Minimal Access Surgery of Ascending and Proximal Arch of the Aorta: A 9-Year Experience

Minoru Tabata, MD, Zain Khalpey, MD, PhD, Sary F. Aranki, MD, Gregory S. Couper, MD, Lawrence H. Cohn, MD, Prem S. Shekar, MD*

Division of Cardiac Surgery, Brigham and Women’s Hospital, Boston, Massachusetts

Accepted for publication March 12, 2007.

* Address correspondence to Dr Shekar, Division of Cardiac Surgery, Brigham and Women’s Hospital, 75 Francis St, Boston, MA 02446 (Email: pshekar{at}partners.org).


   Abstract
Top
 Abstract
Introduction
 Material and Methods
 Results
 Comment
 References
 
Background: Minimal access approaches are becoming readily accepted techniques for cardiac valve surgery. However, the safety or benefit of this approach for aortic surgery has not been well investigated.

Methods: We retrospectively analyzed 128 consecutive patients who underwent ascending aortic replacement (n = 53), proximal aortic arch replacement (n = 7), aortic root replacement (n = 67), or sinus of Valsalva aneurysm repair (n = 1) through an upper hemisternotomy between August 1996 and May 2005. Using matched variables (age, type of procedure, redo operation, and use of circulatory arrest), we constructed two matched cohorts of 79 patients each: a minimally invasive (group A) and full sternotomy (group B) and compared outcomes.

Results: The mean age for the minimally invasive group (n = 128) was 54 years (range, 25 to 83 years). There were six reoperations (4.7%), five (3.9%) urgent operations, and 16 (12.5%) deep hypothermic circulatory arrests. Operative mortality was zero, the median length of hospital stay was 5 days (range, 3 to 21 days), and 112 patients (82.4%) were discharged home. Actuarial survival at 5 years was 97.2%. On comparison between group A and B, there was no significant difference in operative times, mortality, and morbidity. However, group A had shorter median length of stay (5 versus 6 days, p = 0.020) and fewer median units of red blood cell transfusion than group B (2 versus 2.5, p = 0.020).

Conclusions: An upper hemisternotomy approach is safe and feasible for ascending aortic and proximal arch surgical procedures, with excellent early and late outcomes. This approach is associated with shorter hospital stay and less blood transfusion.


   Introduction
Top
 Abstract
 Introduction
Material and Methods
 Results
 Comment
 References
 
Cardiac surgery is rapidly advancing with new techniques such as minimal access, endoscopic, robotic, percutaneous, and endovascular approaches to disease [1–3]. Endovascular grafting of the descending aorta is now a commonly performed minimally invasive practice [4]; however, the indication is still limited by anatomy, such as a tortuous aorta and involvement of important branches. The indication has recently been extended to the aortic arch but this practice is limited by morphologic and hemodynamic characteristics of the aortic arch and is associated with complications [5]. Ascending aortic disease, in particular the aortic root with complicated and precious anatomy, would preclude the use of endovascular grafts and other percutaneous, endoscopic, or robotic techniques.

For ascending aortic and proximal arch operations, minimal access direct techniques are the least invasive procedures that can be safely performed. An upper hemisternotomy approach has been shown to be safe and effective in aortic valve operations [6]. However, the effect of this singular approach in more complicated aortic operations has not been well reported. We evaluated the efficacy, practicality, benefits, and safety of minimally invasive cardiac surgery using an upper hemisternotomy incision on 128 patients who had aortic root, ascending aortic, and proximal aortic arch surgical procedures.


   Material and Methods
Top
 Abstract
 Introduction
 Material and Methods
Results
 Comment
 References
 
Patient Data
We conducted a retrospective review of 128 consecutive patients who underwent aortic root, ascending aortic, and proximal arch operations through an upper hemisternotomy between August 1996 and May 2005. Concomitant aortic valve operations were included, and early and late outcomes were analyzed. Other concomitant operations such as coronary artery bypass grafting, other valve procedures, congenital heart repairs, and descending aortic repairs were excluded. Aortic endarterectomy, aortic plication, and aortic patch repair were excluded. Parasternal and thoracotomy approaches were also excluded.

In the same period, 93 patients underwent ascending aortic, proximal arch and root operations with or without aortic valve procedures through a full sternotomy. Other concomitant or emergency operations were excluded.

Two matched cohorts, each of 79 patients, were constructed between the upper hemisternotomy (group A) and full sternotomy groups (group B). Matched variables included age, type of procedure, redo operations, and use of circulatory arrest. For matching, seven types of operation were categorized: ascending aortic replacement, hemiarch replacement, ascending aortic replacement with aortic valve replacement, hemiarch replacement with aortic valve replacement, Bentall procedure, stentless valve/homograft, and valve-preserving aortic root replacement.

Operative variables, blood transfusion requirement, operative morbidity and mortality, length of hospital stay, and discharge destination were compared between the two matched groups. All preoperative data, in-hospital outcomes, and postdischarge outcomes were collected from Brigham and Women’s Hospital patient medical records and cardiac surgery database using The Society of Thoracic Surgeons (STS) definitions and criteria. This study was approved by the Institutional Review Board (IRB) of Brigham and Women’s Hospital (Protocol number: 2005-P-000982). Patient consent was waived by the IRB for this study.

Indications and Surgical Procedure
We use an upper hemisternotomy approach for the aortic valve, root, ascending aortic, and proximal arch operations unless any other procedures such as coronary artery bypass grafting are required. Although the application of this approach depends on the attending surgeon’s preference, there is no contraindication except in emergency procedures. The upper hemisternotomy (6 to 10 cm) is made from the sternal notch to the level of third or fourth intercostal space and then extended to the right third or fourth intercostals space.

Cardiopulmonary bypass (CPB) is established by cannulation of the direct ascending aortic, arch, femoral or right axillary arterial, and percutaneous femoral venous or direct right atrial cannulation. For reoperations, CPB is established through a femoral or axillary arterial cannulation and femoral venous cannulation before sternotomy. The aortic cross-clamp is applied through the incision (Fig 1).


Figure 1
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  		Fig 1. (A) Upper hemisternotomy incision for minimal access aortic valve surgery. (B) Exposure obtained through this incision. (C) Ascending aortic and percutaneous femoral venous cannulation. (D) Aneurysm resected and replaced by a tube graft.

 
Antegrade cardioplegia is delivered through the aortic root and coronary orifices after aortotomy. Retrograde cardioplegia is delivered through a coronary sinus cannula placed via the right atrial appendage using transesophageal echocardiography guidance. A left ventricular vent is placed through right superior pulmonary vein or aortic valve after aortotomy.

If circulatory arrest is not required for the distal aortic procedure, mild-to-moderate hypothermia (28 to 35°C) is used. If circulatory arrest is required, deep hypothermia (15 to 20°C) is used. For circulatory arrest longer than 30 minutes, we use antegrade cerebral perfusion through right axillary arterial cannula, with occlusion of the innominate artery and left common carotid artery. For reoperations involving a patent left internal mammary artery (LIMA) graft, patients are cooled to 20° to 25°C even if circulatory arrest is not used, and systemic hyperkalemia is used in addition to antegrade and retrograde cardioplegia. When collateral flow from the LIMA graft to the coronary ostia obscures the operative field, CPB flow is turned down temporarily to 500 to 1500 mL/min. Table positioning and external compressions aid in air removal in addition to standard maneuvers for removing air.

Statistical Analysis
Continuous values are expressed as mean ± standard deviation. The median is also reported if the distribution of variables is not normally distributed. Continuous variables were compared with t test or Wilcoxon rank sum test (for nonnormally distributed variables). Categoric variables were compared with {chi}2 test or Fisher exact test when the number of patients in each cell was smaller than five in two-by-two tables. The Kaplan-Meier method was used to analyze the survival. Matched patients’ outcome measures were compared with the paired t test (for normally distributed continuous variables), Wilcoxon signed-rank test (for non-normally distributed continuous variables), or McNemar’s test (for categoric variables). A p < 0.05 was considered statistically significant. Statistical analysis was performed with SPSS 11.5 software (SPSS Inc, Chicago, IL).


   Results
Top
 Abstract
 Introduction
 Material and Methods
 Results
Comment
 References
 
Preoperative Characteristics
Preoperative characteristics of the 128 minimal access patients are summarized in Table 1. The mean age was 53.8 ± 13.9 years (range, 25 to 83 years). Five patients (3.9%) had an urgent operation, which included 4 patients with aortic valve endocarditis and 1 patient with Marfan syndrome with a rapidly enlarging ascending aortic aneurysm. Six patients (4.7%) had reoperative procedures, 3 patients (2.3%) had Marfan syndrome, and 58 patients (45.3%) had a bicuspid aortic valve. Preoperative characteristics of the two matched groups are summarized in Table 2. There was no significant difference in any preoperative variables between the two groups.


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  		Table 1 Preoperative Characteristics of 128 Minimal Access Patients
 

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  		Table 2 Preoperative Characteristics of Matched Patients
 
Operative Variables
Minimal access ascending aortic and proximal arch procedures are summarized in Table 3. The median CPB and aortic cross-clamp times were 145 minutes (range, 52 to 330; mean, 152 ± 57 minutes) and 108 minutes (range, 18 to 248; mean, 108 ± 42 minutes). Sixteen patients (12.5%) required deep hypothermic circulatory arrest, and the median circulatory arrest time was 28 minutes (range, 4 to 73; mean, 32 ± 21 minutes). No patient required a perioperative intraaortic balloon pump. Forty-six patients (35.9%) received homologous blood transfusion. Among them, the median transfused was 2 units of red blood cells (range, 0 to 9; mean, 1.9 ± 1.9 units), 2 units of fresh frozen plasma (range, 0 to 15, mean, 2.1 ± 3.0 units), and 1 unit of platelets (range, 0 to 4; mean, 0.7 ± 0.9 units).


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  		Table 3 Minimal Access Ascending Aortic and Arch Procedures (n = 128)
 
Operative variables in the two matched groups are detailed in Table 4. The type of operation was completely matched. There was no significant difference in CPB, aortic cross-clamp, circulatory arrest times, or the incidence of blood transfusion between the two groups. However, group A received significantly fewer median units of red blood than the group B (2 versus 2.5 units, p = 0.020). There was no significant difference in the amount of fresh frozen plasma or platelets transfused.


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  		Table 4 Operative Outcomes of Matched Patients
 
Operative Outcomes
Operative mortality was zero. The incidences of reoperation for bleeding, perioperative myocardial infarction, deep sternal infection, stroke, and renal failure were 1.6% (2/128), 2.3% (3/128), 0.8% (1/128), 0.8% (1/128), and 0%, respectively. The median length of stay was 5 days (range, 3 to 21 days), and 108 patients (84.4%) were discharged home. Actuarial survival at 5 years was 97.2% (Fig 2). Operative outcomes of the two matched groups are presented in Table 4. Operative mortality was zero in both groups. There was no significant difference in the incidence of reoperation for bleeding, perioperative myocardial infarction, deep sternal wound infection, stroke, and renal failure. The median length of hospital stay was 5 days in group A and 6 days in group B (p = 0.020). Discharge to home rate was 88.6% in group A and 89.9% in group B (p = 0.798).


Figure 2
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  		Fig 2. Kaplan-Meier survival curve. Actuarial survival of 128 minimal access aortic surgery patients.

 

   Comment
Top
 Abstract
 Introduction
 Material and Methods
 Results
 Comment
References
 
An upper hemisternotomy has been shown to be a safe, practical, and effective approach in aortic valve surgery [6]. Some studies have shown that an upper hemisternotomy provides faster postoperative recovery, earlier extubation, less blood loss, less blood transfusion, and less incisional pain compared with a full sternotomy [6–11]. These experiences with minimal access aortic valve surgery have led to its application in aortic surgery; however, the safety and effect of this approach has not been established.

Svensson and colleagues [12] reported 54 cases of minimal access aortic surgery through an upper hemisternotomy with excellent early outcomes. Their experience included 36 ascending aortic repairs, 18 ascending aortic and arch repairs, 26 concomitant aortic valve replacements, 15 concomitant composite valve graft aortic root replacements, and 18 reoperations. In that study, the mean times in minutes were 132 ± 59 for CPB, 91 ± 45 for aortic cross-clamp, and 20 ± 17 for circulatory arrest. Operative mortality was 4%, and the mean length of hospital stay was 6.7 ± 3.7 days. Svensson [13] has also reported 68 cases of minimal access aortic surgery with excellent outcomes in a different study. Byrne and colleagues [14] reported 63 minimal access aortic surgeries through an upper hemisternotomy or parasternal approach, including 44 aortic root replacements, nine aortic valve and supracoronary ascending aortic replacements, and 10 isolated ascending aortic replacements with excellent outcomes. These three studies have shown that minimal access aortic surgery can be performed safely, although they did not compare the outcome between the minimal access approach and conventional full sternotomy.

Our study includes the patients reported by Byrne and colleagues [14] and is a large report of minimal access aortic surgery through an upper hemisternotomy. Operative mortality was zero, and the incidence of operative complications was very low. Adequate exposure was obtained in all cases, with no conversion to full sternotomy required because of poor exposure. Operative times were comparable with full sternotomy. These findings show that minimal access ascending aortic and proximal arch surgery can be performed as safely and comfortably as conventional full sternotomy.

Our study included only 7 patients requiring hemiarch replacement. The feasibility of aortic arch surgery with minimal access approach needs larger patient groups or prospective study for standardization. Of importance, our study has shown that the minimal access group has shorter length of hospital stay and fewer units of red blood cell transfusion than the full sternotomy group. These findings are compatible with previously reported advantages of minimal access surgery in aortic valve surgery [6–10]. The shorter length of hospital stay might be related to less invasiveness, less pain, or less postoperative respiratory compromise, although those variables were not formally evaluated in our study. The fewer red blood cell transfusions requirement was probably due to less blood loss from the sternal edge or dissected surface of adhered tissue and manipulation in reoperative surgery. The demonstrated reduction in hospital stay could result in a savings per patient of $1200 for step down, $2700 for ICU, and $150 for the 0.5 unit reduction in red blood cell transfusion. These are values specific to our institution.

Svensson and colleagues [12, 13] have reported the largest number of reoperative minimal access aortic surgery and described that an upper hemisternotomy is particularly valuable in redo surgery in terms of avoidance of myocardial or graft injuries. We have performed more than 110 cases of reoperative minimal access aortic valve procedures, and our experience is consistent with their finding. Our strategy for reoperative minimal access aortic surgery is the same as that of reoperative aortic valve replacement, which has been previously published [15, 16].

An upper hemisternotomy can be indicated safely for ascending aortic, proximal arch, aortic root, and valve operations. Even total arch replacement with an elephant trunk procedure can be performed [12]. This procedure can be followed by an endovascular graft implant, so a hybrid minimal access total thoracic aortic replacement is possible. This approach is not used for aortic dissection or any other emergency on our service, because extensive exposure is often required and the patient is usually in extremis and requires a standard, effective, and quick operation. Svensson and colleagues [12] have reported minimal access surgery for 16 cases of aortic dissection, but did not mention whether the perioperative circumstances were acute, subacute, or chronic.

A significant limitation to this study is that it is a retrospective review with limited statistical power. A prospective randomized control study is necessary to assess the reproducibility of our findings.

In conclusion, minimal access ascending aortic and proximal arch surgery through an upper hemisternotomy can be performed safely in institutions with a large experience both in minimal access as well as in aortic surgery. It is practical and feasible, with operative times, morbidity, and mortality that are similar to a conventional full sternotomy. Furthermore, this approach is associated with shorter length of hospital stay and less blood transfusion.


   References
Top
 Abstract
 Introduction
 Material and Methods
 Results
 Comment
 References
 

  1. Cribier A, Eltchaninoff H, Tron C, et al. Treatment of calcific aortic stenosis with the percutaneous heart valve: mid-term follow-up from the initial feasibility study: the French experience J Am Coll Cardiol 2006;47:1214-1223.[Abstract/Free Full Text]
  2. Alfieri O, Maisano F, Colombo A. Future of transcatheter repair of the mitral valve Am J Cadiol 2005;96:71L-75L.
  3. Makaroun MS, Dillavou ED, Kee ST, et al. Endovascular treatment of thoracic aortic aneurysms: results of the phase II multicenter trial of the GORE TAG thoracic endoprosthesis J Vasc Surg 2005;41:1-9.[Medline]
  4. Riesenman PJ, Farber MA, Mendes RR, et al. Endovascular repair of lesions involving the descending thoracic aorta J Vasc Surg 2005;42:1063-1074.[Medline]
  5. Ishimaru S. Endografting of the aortic arch J Endovasc Ther 2004;11(suppl 2):II62-II71.[Medline]
  6. Mihaljevic T, Cohn LH, Unic D, Aranki SF, Couper GS, Byrne JG. One thousand minimally invasive valve operationsEarly and late results. Ann Surg 2004;240:529-534.[Medline]
  7. Liu J, Sidiropoulos A, Konertz W. Minimally invasive aortic valve replacement (AVR) compared to standard AVR Eur J Cardiothorac Surg 1999;16(suppl 2):S80-S83.[Medline]
  8. Bonacchi M, Prifti E, Giunti G, Frati G, Sani G. Does ministernotomy improve postoperative outcome in aortic valve operation?A prospective randomized study. Ann Thorac Surg 2002;73:460-466.[Abstract/Free Full Text]
  9. Mächler HE, Bergmann P, Anelli-Monti M, et al. Minimally invasive versus conventional aortic valve operations: a prospective study in 120 patients Ann Thorac Surg 1999;67:1001-1005.[Abstract/Free Full Text]
  10. Dogan S, Dzemali O, Wimmer-Greinecker G, et al. Minimally invasive versus conventional aortic valve replacement: a prospective randomized trial J Heart Valve Dis 2003;12:76-80.[Medline]
  11. Candaele S, Herijgers P, Demeyere R, Flameng W, Evers G. Chest pain after partial upper versus complete sternotomy for aortic valve surgery Acta Cardiol 2003;58:17-21.[Medline]
  12. Svensson LG, Nadolny EM, Kimmel WA. Minimal access aortic surgery including re-operations Eur J Cardiothorac Surg 2001;19:30-33.[Abstract/Free Full Text]
  13. Svensson LG. Progress in ascending and aortic arch surgery: minimally invasive surgery, blood conservation, and neurological deficit prevention Ann Thorac Surg 2002;74:S1786-S1788.[Abstract/Free Full Text]
  14. Byrne JG, Karavas AN, Cohn LH, Adams DH. Minimal access aortic root, valve and complex ascending aortic surgery Curr Cardiol Rep 2000;2:549-557.[Medline]
  15. Byrne JG, Karavas AN, Adams DH, et al. Partial upper re-sternotomy for aortic valve replacement or re-replacement after previous cardiac surgery Eur J Cardiothorac Surg 2000;18:282-286.[Abstract/Free Full Text]
  16. Byrne JG, Karavas AN, Filsoufi F, et al. Aortic valve surgery after previous coronary artery bypass grafting with functioning internal mammary artery grafts Ann Thorac Surg 2002;73:779-784.[Abstract/Free Full Text]

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This Article
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Prem S. Shekar
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