HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Massimo Bonacchi Edvin Prifti Andrea Salica Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bonacchi, M. Articles by Salica, A. Search for Related Content PubMed PubMed Citation Articles by Bonacchi, M. Articles by Salica, A.

Ann Thorac Surg 2000;70:820-823
© 2000 The Society of Thoracic Surgeons

---

Original articles: cardiovascular

Right Y-graft, a new surgical technique using mammary arteries for total myocardial revascularization

^a Istituto di Chirurgia del Cuore e dei Grossi Vasi, II Divisione, Università degli Studi di Roma, "La Sapienza," Rome, Italy
^b Istituto di Chirurgia Cardiovascolare, Ospedale Maggiore della Carità, Novara, Italy

Address reprint requests to Dr Bonacchi, II Divisione di Cardiochirurgia, Istituto di Chirurgia del Cuore e dei Grossi Vasi, Università degli Studi di Roma, "La Sapienza," Policlinico Umberto I, Viale del Policlinico 155, 00161, Roma, Italy
e-mail: mbonacchi{at}hotmail.com

	Abstract

Top Abstract Introduction Material and methods Results Comment References

 
Background. We report a new technique that consists of a right Y-graft using only skeletonized internal mammary arteries (IMA) for total arterial myocardial revascularization.

Methods. This technique consists of anastomosing the in situ left IMA (LIMA) and right IMA (RIMA) to the left anterior descending and obtuse marginal artery, via the transverse sinus, respectively. The distal free LIMA was anastomosed to the right coronary artery and afterwards in a Y fashion to the RIMA stem. Eleven patients with triple-vessel disease underwent coronary artery bypass grafting using this technique. Postoperatively and at follow-up all patients underwent color Doppler contrast-enhanced transthoracic echocardiography (TTE) before and after an adenosine provocation test.

Results. Overall, 33 IMA-coronary anastomoses were made and 11 right Y-grafts were constructed. At 1 week after operation color Doppler contrast-enhanced TTE before and after the adenosine provocation test, respectively, showed an increase in LIMA stem diameter of 0.31 mm and in mean flow 62 mL/min. Coronary flow reserve (CFR) was 2 ± 0.3. The increase in RIMA stem diameter was 0.2 mm and in mean flow was 121.7 mL/min. Coronary flow reserve was 2.5 ± 0.4. Only 1 patient demonstrated an anomalous Doppler pattern, suggesting a partial Y-graft closure.

Conclusions. Such a technique permits total myocardial revascularization using only mammary arteries and left ventricular perfusion from both IMAs simultaneously. The color Doppler contrast-enhanced TTE is a rapid, accurate, and noninvasive test allowing a good assessment of IMA patency.

	Introduction

Top Abstract Introduction Material and methods Results Comment References

 
The saphenous vein graft arteriosclerosis continues [1, 2] to be the major cause of late failure of coronary artery bypass grafting (CABG). The internal mammary artery (IMA) is an ideal bypass conduit because it remains free of arteriosclerosis at late follow-up [3–5]. Employing in situ IMA [13] as an arterial conduit is particularly indicated for young patients with long expected postoperative outcomes. Using both skeletonized IMAs allows total arterial myocardial revascularization (TAMR), in patients with triple-vessel disease without the need for alternative arterial conduits or vein grafts [6–9, 13]. This report describes another alternative for myocardial blood supply: left ventricle myocardial revascularization using both IMAs (LIMA and RIMA anastomosed end to side to left anterior descending artery [LAD] and marginal obtuse [MO] artery, respectively]; the right coronary artery (RCA) is revascularized employing the free LIMA graft in a Y fashion, anastomosed to the side of the in situ RIMA. Postoperatively, the grafts’ patency and their functional status were evaluated by color Doppler contrast-enhanced transthoracic echocardiographic (TTE) before and after the adenosine provocation test [19–20].

	Material and methods

Top Abstract Introduction Material and methods Results Comment References

 
Between February and September 1999, 11 patients had CABG with a new TAMR technique at our institutions. There were 10 men and 1 women, with a mean age of 53.6 ± 5.6 years (range 43 to 60). Two patients presented with a heavily calcified ascending aorta, and 9 were young patients (1 patient with previous bilateral saphenectomy). One patient had diabetes, all were Canadian Cardiovascular Class (CCS) III or IV. None experienced acute myocardial infarction episodes before the operation.

All patients presented with severe triple-vessel disease, with stenotic lesions more than 75% and right-side dominance (Table 1).

Arterial conduits preparation
After a median longitudinal sternotomy incision, the LIMA and RIMA were harvested in a skeletonized fashion extending 2 to 3 cm below the bifurcation, continuing to the superior epigastric arteries without opening the pleural cavities. The mediastinal pleura were dissected gently from the endothoracic fascia, which was incised medially for the whole length and IMA, and both satellite veins were visualized. The sternal and the anterior intercostal branches were ligated with small-sized hemostatic clips only by the IMA side. Both IMAs were prepared carefully until the origin at the subclavian artery. After heparinization, the IMA conduits were clipped distally, cut, clumped proximally with a bulldog, and, until the grafting procedure initiation, covered with a gauze impregnated with papaverine solution (4 mg/mL), which allowed a pharmacologic dilatation.

Surgical technique
The pericardium was opened, the aorta and the right atrium were cannulated in usual fashion, and cardiopulmonary bypass (CPB) started. Normothermia or moderate hypothermia (32°C) were employed during CPB. Intermittent antegrade cold crystalloid cardioplegia technique was employed in intervals of 30 to 40 minutes. In both sides of the superior mediastinum the pleurae-pericardial tissues were dissected and the IMA "beds" were created. Routing of the RIMA behind the superior vena cava and further into the transverse sinus allows additional length [10], facilitating thereby the grafting of the marginal obtuse (MO) coronary arteries via a less circuitous and more protected route. The inside blood pressure will force the graft to have always the right orientation to avoid the graft distortion.

Then, the in-situ RIMA was anastomosed to the MO artery in end-to-side fashion. After that, the in-situ segment of the LIMA was anastomosed in end-to-side fashion to the LAD artery. The remaining end segment of the LIMA was employed as a free graft and was anastomosed distally to the RCA. After the anastomoses’ were completed, the residual adventitial material around the anastomoses area was removed to impede the early or later formation of graft stenosis. The IMA grafts were covered with gauze impregnated with papaverine solution until the moment when the sternum could be closed. The aorta was unclamped. On-pump with beating heart, the first segment of RIMA was clamped in proximally and distally, and the free LIMA graft was anastomosed to the side of the in-situ RIMA, retrolaterally to the superior cava vein in a Y-fashion (Fig 1). The RIMA was then unclamped. All the anastomoses were performed using 8-0 polypropylene continuing sutures. The mean aortic cross-clamp time and duration of CPB were 44 ± 5 minutes (range 35 to 50) and 67 ± 8 minutes (range 54 to 76), respectively.

View larger version (29K): [in this window] [in a new window]   Fig 1. Right Y-graft technique for total arterial myocardial revascularization. (LIMA = left internal mammary artery [in situ]; RIMA = right internal mammary artery [in situ]; f-LIMA = free graft of the LIMA; LAD = left anterior descending artery; MO = marginal obtuse artery; RC = right coronary artery.)

Postoperative graft evaluation
The anatomic-functional postoperative evaluation was performed for all patients at 1 week and 3 months after the operation by color Doppler contrast-enhanced TTE before and after adenosine provocation testing. The probe was positioned at the first and second intercostal space. The IMA’s diameter, peak systolic velocity, peak diastolic velocity, mean flow (MF), and coronary flow reserve (CFR) were measured for LIMA and RIMA separately. These data were registered at rest and 1 minute after adenosine administration (140 µ · kg^-1 · min^-1) for 4 minutes. The mean systemic arterial pressure and mean heart rate were maintained at 85 ± 12 mm Hg and 82 ± 7 beats per minute during the examination. At 3 months all patients underwent the same examination (Table 2).

	Results

Top Abstract Introduction Material and methods Results Comment References

 
Overall, 33 end-to-side, IMA-coronary artery anastomoses were made and 11 right Y-grafts between the free LIMA graft and the in-situ RIMA were constructed. All patients had an uneventful postoperative recovery (hospital stay 7.5 ± 2 days). There were no hospital deaths, ECG or enzymatic alterations, postoperative stroke episodes, or deep sternal wound infections. At 1 week the color Doppler contrast-enhanced TTE at rest and after adenosine provocation testing, respectively, demonstrated (the data were indexed by corporeal surface = 1.78 ± 0.25) for the LIMA stem a diameter_i 1.38 ± 0.2 versus 1.69 ± 0.15 mm/m² (p < 0.05), MF_i 62 ± 5.3 versus 124 ± 8 mL · min^-1 · m^-2 (p < 0.05), and CFR 2 ± 0.3; and for the RIMA stem a diameter_i 1.48 ± 0.2 versus 1.69 ± 0.15 mm/m² (p < 0.05), MF_i 81.6 ± 10.6 versus 203.3 ± 24 mL · min^-1 · m^-2 (p < 0.05), and CFR 2.5 ± 0.4. Only in 1 patient was found an anomalous TTE color Doppler pattern of RIMA, suggesting a partial composite graft obstruction. Although asymptomatic, he underwent coronary angiography examination, which revealed an occlusion of the free LIMA graft.

Three months after the surgical procedure all patients were alive and free of angina. The IMA stem evaluation by color Doppler TTE revealed a higher CFR of LIMA (2.1 ± 0.3) and RIMA (3.1 ± 0.5), but the difference was not statistically significant.

	Comment

Top Abstract Introduction Material and methods Results Comment References

 
Myocardial revascularization using only IMA grafts has developed in an incremental manner from using in-situ LIMA as a single graft to the LAD artery, to the use of bilateral free or sequential IMAs, and now recently, to the use of preconstructed composite grafts (free RIMA grafts that are attached to the side of an in-situ LIMA) [8, 11–15]. The microanatomy and vascular reactivity of IMAs have been recently defined, providing valuable information on IMAs’ freedom from later obstruction [4, 5]. The in-situ LIMA anastomosed to the LAD artery is the most important graft in reducing recurrent angina, infarction, or late mortality after CABG [18]. Free IMA grafts anastomosed to the aorta have a lower patency because of more turbulence causing intimal damage than IMAs in situ or composite conduits arising from IMAs [13]. It appears that maximal long-term benefits by using bilateral IMAs is achieved by grafting these arterial conduits to the coronary arteries that supply more left ventricular myocardial muscle [6].

Using the free-end segment of LIMA anastomosed proximally to the first segment of RIMA as an arterial revascularization of the RCA has not been reported previously in the literature. We believe that this technique is of potential benefit to selected patients because only IMAs are used, as the best arterial conduits [15], and there are blood supply advantages related to grafting both IMAs to the coronary arteries of the left ventricle [6, 17]. Such a technique avoids the difficulties of anastomosing a thin-walled and small-caliber vessel like the IMA, radial artery, or gastroepiploic artery with the thick wall of the ascending aorta, and the risk of neurologic dysfunction and stroke, especially if the ascending aorta is diseased [13]. There are no grafts crossing the midline behind the sternum, and the RIMA, the LIMA, and the anastomosis RIMA-free LIMA graft are in a very safe position, which decreases the risk in case of surgical mediastinal revision in the postoperative course or later reoperation. The skeletonized technique reduces the traumatic injuries of the mediastinal tissues during the dissection procedure, resulting in a lower incidence of postoperative infectious risk [16]. The preparation of IMA conduits and their routing according to the above-described technique allows enough graft material for revascularization of the distal mid third of the LAD artery and the right Y-graft construction. In our practice we found it very difficult to perform this technique in cases with critical stenosis of the distal third of the LAD and posterior descending arteries. Even in these situations, we hypothesized that such a technique could be employed in association with coronary endoartherectomy if indicated. The CPB and clamping times are shorter because there are no proximal anastomoses performed to the ascending aorta and the right Y graft is constructed on-pump with beating heart.

The hypoperfusion syndrome was not verified in other series of patients who underwent CABG using composite grafts [19, 20] as well as in our small series of patients because the construction of a composite graft increases the flow through the IMA stem versus an IMA simple graft (in our data, in the early postoperative period, at rest: RIMA MF_i = 81.6 ± 10.6 mL · min^-1 · m^-2 versus LIMA MF_i = 62 ± 5.3; p < 0.05). The evaluation of flow dynamic was made by color-Doppler contrast-enhanced TTE (by levovist) and adenosine provocation testing (extensive data will be reported separately). This functional test demonstrates that the flow reserve of the proximal IMA is adequate for myocardial supply under stress for multiple coronary anastomoses. It permits evaluation of myocardial perfusion through the CFR measurement (Table 2). This examination demonstrated good flows and velocities of IMA grafts at 1 week and 3 months after the surgical procedure. The diameter and CFR measured at the RIMA stem were significantly higher versus CFR measured at the LIMA stem (p < 0.05), probably because of the higher run-off of the RIMA due to the composite graft (right Y graft) anastomosed to the RCA and distal segment of the RIMA anastomosed to the MO artery. At follow-up, the significant increment of IMA diameters (p < 0.05), with a consequent improvement in flow capacity, seems to be an anatomic, functional mechanism adapting the blood flow requirements of the respective myocardium territories [21].

In this series we found only 1 surgical failure, which consisted of early occlusion of the free LIMA graft (Y composite graft). That patient’s preoperative coronary angiography was reexamined and revealed an overestimation of the stenotic lesion of the RCA. Such a condition determined a competitive flow between the free LIMA graft and the native RCA, resulting in the graft’s occlusion. Such a result demonstrates that the presence of noncritical stenosis of the coronary artery is a contraindication to this technique. We hypothesize that another contraindication to this technique is the possible combination of three anatomic functional conditions: (1) noncritical stenotic lesion to the circumflex artery, (2) small-caliber RIMA, and (3) a very good run-off of the RC, which determines a "steal phenomenon" of the blood flow from the RCA to the circumflex artery.

In conclusion, the right Y-graft technique, which consists of two end-to side anastomoses, and one Y-graft composite permits TAMR using only skeletonized IMAs. This technique preserves the anastomosis of the in-situ LIMA to the LAD artery and provides left ventricular myocardium reperfusion from both IMAs. The excellent early results were demonstrated by the postoperative color Doppler contrast-enhanced TTE examination before and after adenosine provocation testing. We define the reported procedure as the surgical technique of choice for TAMR, offering better postoperative outcome and reduced CPB and clamping time, and it should be part of the coronary surgical armamentarium to be used for selected patients with coronary artery disease. This technique is useful also in patients with aortic calcification where it can be employed according to the "nontouch" principle. According our experience, the color Doppler contrast-enhanced TTE is a safe, rapid, accurate and noninvasive test, which allows a good assessment of IMA patency and CFR evaluation.

	References

Top Abstract Introduction Material and methods Results Comment References

 

1. Neitzel G.F., Barboriak J.J., Pintar K., Qureshi I. Atherosclerosis in aorto-coronary bypass grafts. Morphologic study and risk factor analysis 6 to 12 years after surgery. Arteriosclerosis 1986;6:594-600.[Abstract]
2. Butany J.W., David T.E., Ohja M. Hitological and morphometric analyses of early and late aortocoronary vein grafts and distal anastomoses. Can J Cardiol 1998;14:671-677.[Medline]
3. Okies J.E., Page U.S., Bigelow J.C., et al. The left internal mammary artery. Circulation 1984;70(Suppl I):I21.
4. Van Son J.A.M., Smedts F., Vincent J.G., et al. Comparative anatomical studies of various arterial conduits for myocardial revascularization. J Thorac Cardiovasc Surg 1990;99:703-707.[Abstract]
5. Sons H.J., Goderhardt E., Kunert J., et al. Internal thoracic artery. J Thorac Cardiovasc Surg 1993;106:1192-1195.[Abstract]
6. Schmidt S.E., Jones J.W., Thornby J.I., et al. Improved survival with multiple left-sided bilateral internal thoracic arteries grafts. Ann Thorac Surg 1997;64:9-15.[Abstract/Free Full Text]
7. Tector A.J., Amundsen S., Schmahl T.M., et al. Total revascularization with T grafts. Ann Thorac Surg 1994;57:33-39.[Abstract]
8. Tector A.J., Kress D.C., Downey F.X., Schmahl T.M. Complete revascularization with internal thoracic artery grafts. Semin Thorac Cardiovasc Surg 1996;8:29-41.[Medline]
9. Odayan M.K., Paterson H.S. Myocardial revascularization with the left internal thoracic artery Y graft configuration. Ann Thorac Surg 1999;67:1359-1361.[Abstract/Free Full Text]
10. Pliam M.B., Zapolanski A. Retrocaval routing of the right internal thoracic artery. Ann Thorac Surg 1993;56:181-182.[Abstract]
11. Tatoulis J., Buxton B.F., Fuller J.A. Results of 1454 free right internal thoracic artery-to-coronary artery grafts. Ann Thorac Surg 1997;64:1263-1269.[Abstract/Free Full Text]
12. Green G.E., Stertzer S.H., Reppert E.H. Coronary arterial bypass grafts. Ann Thorac Surg 1968;5:443-450.[Medline]
13. Calafiore A.N., Di Giammarco G., Luciani N., et al. Composite arterial conduits for a wider arterial myocardial revascularization. Ann Thorac Surg 1994;58:185-190.[Abstract]
14. Pitsis A.A., Cullen H.C., Musumeci F., et al. A new strategy of total revascularization. Ann Thorac Surg 1999;67:1186-1187.[Abstract/Free Full Text]
15. Brown A.H., Dougenis D. Dissection of the two internal mammary arteries with maximal exposure and minimal adverse sequlae by means of inexpensive, simple atraumatical retractor. J Thorac Cardiovasc Surg 1991;102:753-756.[Abstract]
16. Calafiore A.M., Vitolla G., Iaco A., et al. Bilateral internal mammary artery grafting. Midterm results of pedicled versus skeletonized conduits. Ann Thorac Surg 1999;67:1637-1642.[Abstract/Free Full Text]
17. Lytle BW, Arnold JH, Loop FD, et al. Two internal thoracic arteries are better than one. Presented at the AATS meeting, Boston, Massachusetts, May 3–6, 1998.
18. Loop F., Little B., Cosgrove D., et al. Influence of the internal mammary artery graft on 10-year survival and other cardiac events. N Engl J Med 1986;314:1-6.[Abstract]
19. Caiati C., Montaldo C., Zedda N., et al. New non invasive method for coronary flow reserve assessment. Contrast-enhanced transthoracic second harmonic echo Doppler. Circulation 1999;99:771-778.[Abstract/Free Full Text]
20. Wendler O., Hennen B., Markwirth T., et al. T grafts with the right internal thoracic artery to left internal thoracic artery versus the left internal thoracic artery, and radial artery. J Thorac Cardiovasc Surg 1999;118:841-848.[Abstract/Free Full Text]
21. Akasara T., Yoshikawa J., Yoshida K. Flow capacity of internal mammary artery artery grafts. Early restriction and later improvement assessed by Doppler guide wire. J Am Coll Cardiol 1995;25:640-647.[Abstract]

This article has been cited by other articles:

				D. Pevni, I. Hertz, B. Medalion, A. Kramer, Y. Paz, G. Uretzky, and R. Mohr Angiographic evidence for reduced graft patency due to competitive flow in composite arterial T-grafts J. Thorac. Cardiovasc. Surg., May 1, 2007; 133(5): 1220 - 1225. [Abstract] [Full Text] [PDF]

				M. Bonacchi, E. Prifti, M. Maiani, G. Giunti, and M. Leacche Skeletonized bilateral internal mammary arteries for non-elective surgical revascularization in unstable angina Eur. J. Cardiothorac. Surg., July 1, 2005; 28(1): 120 - 126. [Abstract] [Full Text] [PDF]

				M Bonacchi, F Battaglia, E Prifti, M Leacche, N S Nathan, G Sani, and G Popoff Early and late outcome of skeletonised bilateral internal mammary arteries anastomosed to the left coronary system Heart, February 1, 2005; 91(2): 195 - 202. [Abstract] [Full Text] [PDF]

				M. Bonacchi, E. Prifti, F. Battaglia, G. Frati, G. Sani, and G. Popoff In situ retrocaval skeletonized right internal thoracic artery anastomosed to the circumflex system via transverse sinus: Technical aspects and postoperative outcome J. Thorac. Cardiovasc. Surg., November 1, 2003; 126(5): 1302 - 1313. [Abstract] [Full Text] [PDF]

				M. Bonacchi, E. Prifti, G. Giunti, and G. Sani Retrocaval right internal mammary artery for left ventricular marginal arteries grafting Eur. J. Cardiothorac. Surg., May 1, 2002; 21(5): 952 - 952. [Full Text] [PDF]

				R. Ramadan Reply to Bonnachi et al. Eur. J. Cardiothorac. Surg., May 1, 2002; 21(5): 953 - 953. [Full Text] [PDF]

				S. Al-Ruzzeh, S. George, M. Bustami, K. Nakamura, C. Ilsley, and M. Amrani Early clinical and angiographic outcome of the pedicled right internal thoracic artery graft to the left anterior descending artery Ann. Thorac. Surg., May 1, 2002; 73(5): 1431 - 1435. [Abstract] [Full Text] [PDF]

				P. Totaro, C. Fucci, and G. Minzioni Preserved pleura space integrity and respiratory dysfunction after coronary surgery Eur. J. Cardiothorac. Surg., November 1, 2001; 20(5): 1067 - 1068. [Full Text] [PDF]

				M. Bonacchi, E. Prifti, G. Giunti, G. Frati, and G. Sani Urgent surgical revascularization of unstable angina. Influence of double mammary arteries Eur. J. Cardiothorac. Surg., October 1, 2001; 20(4): 747 - 754. [Abstract] [Full Text] [PDF]

				E. Prifti, M. Bonacchi, G. Frati, P. Proietti, G. Giunti, and M. Leacche {lambda}graft with the radial artery or free left internal mammary artery anastomosed to the right internal mammary artery: flow dynamics Ann. Thorac. Surg., October 1, 2001; 72(4): 1275 - 1281. [Abstract] [Full Text] [PDF]

				M. Bonacchi, E. Prifti, G. Giunti, A. Salica, G. Frati, and G. Sani Respiratory dysfunction after coronary artery bypass grafting employing bilateral internal mammary arteries: the influence of intact pleura Eur. J. Cardiothorac. Surg., June 1, 2001; 19(6): 827 - 833. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Massimo Bonacchi Edvin Prifti Andrea Salica Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bonacchi, M. Articles by Salica, A. Search for Related Content PubMed PubMed Citation Articles by Bonacchi, M. Articles by Salica, A.