Asian Cardiovasc Thorac Ann 2007;15:381-385
© 2007 Asia Publishing EXchange Ltd
Total Arterial Revascularization and Concomitant Aortic Valve Replacement
Malakh Shrestha, MBBS,
Nawid Khaladj, MD,
Hiroyuki Kamiya, MD,
Michael Maringka, MD,
Axel Haverich, MD,
Christian Hagl, MD
Division of Cardiac, Thoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany
For reprint information contact: Malakh Shrestha, MBBS, Tel: 49 511 532 2157, Fax: 49 511 532 5404, Email: Shrestha.Malakh.Lal{at}mh-hannover.de, Division of Cardiac, Thoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
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ABSTRACT
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The safety of total arterial revascularization with a left internal thoracic artery-radial artery T-graft was evaluated in patients with at least two-vessel coronary artery disease and aortic valve stenosis requiring concomitant aortic valve replacement. From June 2001 to January 2005, 18 patients underwent aortic valve replacement and total arterial revascularization, while 101 had aortic valve replacement and conventional grafting. By matching age, sex, left ventricular ejection fraction, and number of distal anastomoses, 1:2 matched groups were generated: 15 patients with a left internal thoracic-radial artery T-graft, and 30 with left internal thoracic artery and additional vein grafts. Aortic cross clamp and cardiopulmonary bypass times were similar in both groups. There were no significant differences in postoperative data between the groups. Early mortality was 0% in the T-graft group and 2% in those with conventional grafts. Follow-up ranged from 2 to 50 months. Event-free survival was 100% in the T-graft group and 90% in the conventional graft group. Total arterial grafting with a left internal thoracic-radial artery T-graft can be performed in selected patients with aortic valve stenosis requiring simultaneous aortic valve replacement.
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INTRODUCTION
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With the increase in late saphenous vein graft disease, surgeons have begun using additional arterial grafts for multivessel coronary artery bypass grafting (CABG), and several studies have demonstrated better long-term outcomes.1–4 Thus, total arterial revascularization in CABG has gained interest.5–9 Total arterial revascularization can be achieved in most patients by proximal anastomosis of the radial artery (RA) to the side of the left internal thoracic artery (LITA) in a T-graft configuration, with maximum graft economy.8,9 However, this technique makes the entire revascularization dependent on the proximal LITA, and there has been skepticism about the ability of the LITA to provide adequate flow, particularly in the face of left ventricular (LV) hypertrophy.10 Patients with aortic valve stenosis generally have LV hypertrophy. There have been no reports of grafting strategies in patients with aortic valve stenosis and extensive coronary artery disease requiring concomitant aortic valve replacement (AVR) and CABG. In view of the excellent results of total arterial revascularization with the LITA-RA T-graft in isolated CABG in our institute, we performed this technique in patients with aortic valve stenosis requiring AVR since June 2001. The aim of this study was to evaluate the safety of total arterial revascularization with the LITA-RA T-graft in patients with multivessel coronary disease undergoing concomitant AVR. Their results were compared with a matched cohort of patients who had AVR with conventional CABG using LITA and additional vein grafts.
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PATIENTS AND METHODS
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From June 2001 to January 2005, 301 patients with coronary artery disease and aortic valve stenosis underwent CABG and concomitant AVR in our institute. Of these, 119 patients had multivessel coronary disease and aortic valve stenosis; 18 underwent total arterial revascularization with a LITA-RA T-graft, and 101 had conventional CABG with LITA and additional vein grafts, in elective settings. Informed consent was obtained from every patient. As use of the LITA-RA T-graft is a standard procedure in our institution, we did not need ethical committee approval. According to the regulations, ethical committee approval was waived by the chairman of our department. The surgical technique in both groups was applied according to the surgeon’s preference. Patients needing single-vessel CABG with AVR and redo cases were excluded from this analysis. Patient characteristics and perioperative factors are presented in Table 1
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To produce two statistically comparable groups, matching was performed using the following variables: age, sex, LV ejection fraction, and number of distal anastomoses. Through this process, 1:2 matched groups were generated: 15 patients who underwent AVR and total arterial revascularization with the LITA-RA T-graft (T-graft group) and 30 who underwent AVR and conventional CABG with LITA and additional vein grafts (conventional CABG group). In this process, 3 patients who underwent AVR and revascularization with the LITA-RA T-graft and had only one matched patient were excluded. Patient characteristics are presented in Table 2. There were no significant differences in any factor between groups. Late follow-up was carried out via telephone calls, with a 100% contact rate. The mean follow-up period was 23 ± 16 months in the T-graft group and 20 ± 14 months in the conventional CABG group.
After sternotomy and graft harvest, the pericardium was opened longitudinally. Care was taken to avoid damage or spasm of the potential grafts when using electrocautery. In the T-graft group, anastomosis between the LITA and RA was made first, using 8/0 polypropylene running suture in an end-to-side perpendicular fashion. After systemic heparinization, cardiopulmonary bypass was initiated. The coronary artery status was grossly evaluated. The ascending aorta was clamped, and myocardial protection was achieved with cold crystalloid or blood cardioplegia. The distal coronary anastomoses were then performed. After repeating cardioplegia administration if necessary, the aorta was opened, the native aortic valve and any calcification on the aortic annulus were removed, and the size of prosthesis was decided. After implantation of the aortic valve prosthesis, the aortotomy was closed, the heart was de-aired and perfused again. In the conventional CABG group, proximal anastomoses of vein grafts were performed by side clamping the ascending aorta.
Both groups received the same postoperative medical care. Vasopressors were avoided in the perioperative period, intravenous nitrates were administered liberally, and the same anticoagulation protocol was followed in both groups. This included intravenous heparin followed by coumadin derivatives for at least 3 months, then antiplatelet agents (e.g. aspirin 100 mg per day) in patients with biological valves. In those with mechanical valves, early postoperative intravenous heparin was followed by lifelong coumadin.
Results are expressed as mean ± standard deviation. Statistical analysis was performed using Student’s t test for continuous variables or the chi-squared test (Fisher’s exact test if n < 5) for categorical variables. Event-free survival analysis methods were based on the incidence of recurrence of angina, revascularization, and cardiac death. Kaplan-Meier analysis was used for comparison of groups. A p value less than 0.05 was considered significant. All statistical analyses were performed using SPSS version 10.0 software (SPSS, Inc., Chicago, IL, USA).
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RESULTS
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Perioperative factors and early complications are listed in Table 3. The aortic cross clamp and cardiopulmonary bypass times were not different between groups. Early mortality was 0% in the T-graft group and 2% in the conventional CABG group (p = 0.47); however, the small number of patients does not allow definite conclusions concerning the superiority of one or other surgical approach. There were no significant differences in postoperative ventilation time or early complications between groups. In the follow-up period, 2 patients in the conventional CABG group had percutaneous transluminal coronary angioplasty because of occlusion of a venous bypass graft, and one patient died from myocardial infarction. No patient in the T-graft group needed repeat coronary revascularization or died during follow-up. Thus, the event-free survival rate was 100% in the T-graft group and 90% in the conventional CABG group (p = 0.21). The postoperative NYHA status was 1.1 ± 0.3 in the T-graft group and 1.3 ± 0.6 in the conventional CABG group (p = 0.23).
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DISCUSSION
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This study demonstrates that total arterial revascularization with the LITA-RA T-graft is also an option in patients requiring simultaneous AVR for aortic valve stenosis, with acceptable short-term results similar to those of conventional CABG with LITA and additional vein grafts. The short-term results in patients receiving AVR and total arterial revascularization tended to be better than in those receiving conventional CABG and AVR.
The right and left internal thoracic arteries, radial artery, and gastroepiploic artery can be used as arterial conduits. Due to limitations in length, it is difficult to perform total arterial revascularization with only in situ graft materials in patients with multivessel coronary artery disease. To achieve total arterial revascularization with maximal graft economy, Tector and colleagues11 introduced the T-graft technique with both internal thoracic arteries in 1994. Later, this technique was used with LITA and RA. The LITA is connected to the anterior myocardial wall coronary arteries, and a second arterial conduit (e.g. RA) is anastomosed to the LITA (after anastomosis with the posterior and lateral coronary vessels). Thus, the LITA delivers blood to all the coronary arteries and hence to a large portion of the myocardium. Despite concern about the flow capacity of the LITA as a single in-flow for all anastomoses, this T-graft technique has become established with the accumulation of encouraging clinical findings including flow characteristics of the T-graft in isolated coronary revascularization.8,9
However, it was unclear whether this strategy could be safely performed in patients requiring simultaneous AVR for aortic stenosis. Akasaka and colleagues12 reported that LITA flow was reduced soon after the operation, and the early postoperative flow capacity was less than that of the saphenous vein graft. However, they also observed this restricted flow capacity to improve late postoperatively because of an increase in graft diameter and a decrease in the baseline level of flow velocity.12 Their findings suggest that the acute phase after CABG with the T-graft configuration can be critical. On the other hand, Affleck and colleagues13 performed flow measurements during the operation and concluded that the hemodynamics of the LITA-RA T-graft were intrinsically adequate to meet the flow requirements of the heart in the early postoperative period.
The short-term results in patients receiving T-grafts tended to be better than in those undergoing conventional CABG, although the difference did not reach statistical significance, perhaps because of the small number of patients. It appears that the long-term advantages of total arterial revascularization are also manifest in patients requiring simultaneous AVR and CABG, after completion of the potentially critical early postoperative phase. As shown in Table 1
, we preferred to perform AVR and total arterial revascularization in young patients, because we believe that they benefit more than older patients. Moreover, until this analysis, there have been no guidelines for grafting in patients who require simultaneous AVR. Thus, a selection bias existed. Due to the small number of patients, propensity score matching by multivariate regression analysis was not used in this study.
Despite the small number of patients and the retrospective nature of this study, we were able to show that our strategy is a feasible option in patients undergoing AVR and concomitant coronary revascularization. The lack of preoperative echocardiographic data regarding LV hypertrophy and LV dimensions is a further limitation of this study; nevertheless we are encouraged to start a prospective randomized study to show the potential advantages of this technique in a larger patient cohort. We conclude that total arterial revascularization with a LITA-RA T-graft can be performed safely in selected patients with multivessel coronary artery disease and aortic valve stenosis requiring simultaneous AVR.
Presented at the 14th Annual Meeting of Asian Society for Cardiovascular Surgery, Osaka, Japan, June 1–3, 2006.
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REFERENCES
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- Reardon MJ, Conklin LD, Reardon PR, Baldwin JC. Coronary artery bypass conduits: review of current status. J Cardiovasc Surg (Torino) 1997;38:201–9.[Medline]
- Lytle BW, Loop FD, Taylor PC, Simpfendorfer C, Kramer JR, Ratliff NB, et al. Vein graft disease: the clinical impact of stenoses in saphenous vein bypass grafts to coronary arteries. J Thorac Cardiovasc Surg 1992;103:831–40.[Abstract]
- Barner HB, Sundt TM 3rd. Multiple arterial grafts and survival. Curr Opin Cardiol 1999;14:501–5.[Medline]
- Pick AW, Orszulak TA, Anderson BJ, Schaff HV. Single versus bilateral internal mammary artery grafts: 10-year outcome analysis. Ann Thorac Surg 1997;64:599–605.[Abstract/Free Full Text]
- Weinschelbaum EE, Gabe ED, Macchia A, Smimmo R, Suarez LD. Total myocardial revascularization with arterial conduits: radial artery combined with internal thoracic arteries. J Thorac Cardiovasc Surg 1997;114:911–6.[Abstract/Free Full Text]
- Lytle BW, Blackstone EH, Loop FD, Houghtaling PL, Arnold JH, Akhrass R, et al. Two internal thoracic artery grafts are better than one. J Thorac Cardiovasc Surg 1999;117:855–72.[Abstract/Free Full Text]
- Kamiya H, Watanabe G, Takemura H, Tomita S, Nagamine H, Kanamori T. Total arterial revascularization with composite skeletonized gastroepiploic artery graft in off-pump coronary artery bypass grafting. J Thorac Cardiovasc Surg 2004;127:1151–7.[Abstract/Free Full Text]
- Sundt TM 3rd, Barner HB, Camillo CJ, Gay WA Jr. Total arterial revascularization with an internal thoracic artery and radial artery T graft. Ann Thorac Surg 1999;68:399–405.[Abstract/Free Full Text]
- Wendler O, Hennen B, Demertzis S, Markwirth T, Tscholl D, Lausberg H, et al. Complete arterial revascularization in multivessel coronary artery disease with 2 conduits (skeletonized grafts and T grafts). Circulation 2000;102(19 Suppl 3):III79–83.[Medline]
- Sakaguchi G, Tadamura E, Ohnaka M, Tambara K, Nishimura K, Komeda M. Composite arterial Y graft has less coronary flow reserve than independent grafts. Ann Thorac Surg 2002;74:493–6.[Abstract/Free Full Text]
- Tector AJ, Amundsen S, Schmahl TM, Kress DC, Peter M. Total revascularization with T grafts. Ann Thorac Surg 1994;57:33–9.[Abstract]
- Akasaka T, Yoshikawa J, Yoshida K, Maeda K, Hozumi T, Nasu M, et al. Flow capacity of internal mammary artery grafts: early restriction and later improvement assessed by Doppler guide wire. Comparison with saphenous vein grafts. J Am Coll Cardiol 1995;25:640–7.[Abstract]
- Affleck DG, Barner HB, Bailey MS, Perry LA, Maniar H, Prasad SM, et al. Flow dynamics of the internal thoracic and radial artery T-graft. Ann Thorac Surg 2004;78:1290–4.[Abstract/Free Full Text]
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ABSTRACT
INTRODUCTION
