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(a)

(d)

RITA

2nd I/C

LITA

3rd I/C

(c)

(b)

Fig.45.1 Construction of the proximal Y- graft anastomosis between the left internal thoracic artery (LITA) and the free right internal thoracic

artery (RITA). Usually just above the third intercostal (I/ C) branch, at the level of the base of the left atrial appendage, or just above the level of the pulmonary valve.

there is a satisfactory parallel lie (not too lateral), length, and the LITA is of sucient calibre not to compromise nor hypoperfuse the LAD.

e RITA limb revascularizes the le ventricular lateral wall. If an intermediate or high rst marginal is to be graed, then an LITA/ RITA T- anastomosis is preferred to establish the best lie and orientation.

Distal anastomoses to the circumex marginal are preferably constructed as parallel (if length allows a gentle curved lie between anastomoses), or as diamond- shaped if crossing at 90°, or when length is a consideration. e RITA will oen reach the distal circumex system, and even the posterior descending branch (PDA) of the right coronary artery and some surgeons routinely revascularize the PDA with the RITA limb in normal- sized hearts.

Adventitial tacking sutures of 6- 0 polypropylene are used to orientate and hold the gras in place between sequential anastomoses. Each anastomosis is tested as it is performed.

LITA/ RITA composite gras are ideally suited to o- pump procedures, commencing with the LAD, then the lateral and inferior walls. Progressive revascularization and restoration of the coronary blood supply to each successive territory graed is achieved.

is conguration also allows an anaortic, no- touch technique that avoids manipulation of the aorta, and is particularly useful for older patients, or where there is plaque in the aorta, and is associated with a reduced stroke rate.

Inow via the single LITA limb is sucient to support the coronary circulation.

Bilateral ITA graing is generally avoided in obese insulindependent diabetics (body mass index >35kg/ m), and in severe chronic obstructive airways disease.

Patency of the ITA is repeatedly reported as greater than 95% at 10years and greater than 90% at 20years, and survival as 75– 85% at 10years, depending on age at surgery.,

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(a) (b)

LITA

String

Fig.45.2 (a) Angiogram of the Y limb of a right internal thoracic artery

Y- graft to the circumﬂex system. Note the parallel anastomoses that have been constructed with the circumﬂex marginal branches. (b)Left internal thoracic artery (LITA) and radial artery (RA) Y- graft arrangement with the LITA running to the left anterior descending artery, and the RA running to the inferior circumﬂex system, and then a string sign in a distal segment to a small posterior descending branch.

LITA– radial artery composite Y- or T- grafts

Some surgeons use this technique routinely. Its advantages are eciency as the le RA can be harvested simultaneously with the LITA,

the sternum is less vulnerable to infection and malunion, and superior graing versatility, as the RA is longer and will more readily reach the PDA in most hearts. e anastomotic technique is identical to that of a LITA/ RITA Y- gra.

Disadvantages include potentially a size disparity between the LITA and the proximal RA at the Y/ T- anastomosis with potential distortion, and possible steal into the RA limb, as it has a larger diameter, and oen ows to multiple sequential distal coronaries with a combined larger run- o. e RA may be inuenced by (moderate) native coronary stenosis with unpredictable autoregulation in dierent segments of the RA limb (Fig. 45.2b). e distal- most anastomosis (e.g. PDA) appears to be more vulnerable to reduced patency with this technique. If possible, the most distal anastomosis should be made to a relatively large, tightly stenosed coronary artery to maximally enhance ow for the entire length of the gra.

Patency and clinical results are reported to be identical to those for LITA/ RITA Y- gras.

LITA– saphenous vein Y- grafts

Traditionally these have been infrequently used, for example, in instances of conduit shortage, or if a saphenous vein gra does not reach the aorta, and is therefore necessarily anastomosed to the LITA for inow. Recently, however, this conguration has been used as the prime graing strategy and has demonstrated excellent early patency results in both the LITA and saphenous vein

OM1

OM2

Fig.45.3 Radial artery (RA) composite ‘baby Y- graft’ to adjacent circumﬂex marginal branches which were not anatomically well placed for a

sequential graft. OM, obtuse marginal.

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segments (see Chapter32). Distribution of LITA- generated nitric oxide down the saphenous vein gra component may be a possible explanation.

An extremely distal, le ventricular branch of the right coronary artery may be reached by a segment of arterial gra with inow from the posterior descending coronary gra.

A separate 4– 6cm RA, ITA, or saphenous vein segment (5– 6cm

Planned ‘baby Y- grafts’

long) is graed distally in the usual manner to the le ventricular branch and then anastomosed proximally end- to- side (usually between the acute margin and the crux) to the main (e.g. PDA) gra

ese are used to accommodate anatomical situations where sequential graing is not possible, or not desirable. Alaterally placed diagonal artery may be best graed with a short Y- gra segment from the LITA using redundant distal LITA, a segment of RITA,

aer lling the heart to judge the exact length. e construction of this proximal inow end- to- side anastomosis with continuous 7- 0 polypropylene can be facilitated by placing a folded gauze or small pack beneath the gras to create a working platform.

or of RA. is strategy avoids potential kinking, or stretching of an LITA sequential gra.

When the stenosis is in the mid portion of a rst marginal, and

End- to- end extensiongrafts

proximally in a distal marginal, sequential graing may be suboptimal. Aplanned ‘baby Y- gra’ allows uncompromised anastomoses to the optimal segments of the target vessels (Fig. 45.3).

ese are sometimes used to facilitate revascularization of the inferolateral aspect of the heart, particularly in anaortic CABG

(a)

RITA

(b)

Fig.45.4 (a) Extension of the right internal thoracic artery (RITA) end- to- end with the radial artery (RA). (b)Similar extension using an end- to- side

technique and a vascular clip to exclude the ‘blind pouch’ at the superior end of the graft extension which also directs ﬂow in a linear, longitudinal manner.

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(especially o- pump CABG). e RITA is extended end- to- end, with the RA, or residual LITA or saphenous vein. Awide end- to- end anastomosis is constructed with continuous 7- 0 polypropylene with widely spatulated ends. e suture is tied once the RITA ow is released into the distal limb to avoid a purse- string eect and ensure maximum anastomotic diameter (Fig. 45.4a).

Alternatively, the extension anastomosis can be constructed endto- side, particularly if there is a size discrepancy. An appropriately placed vascular clip excludes the proximal ‘blind pouch’ and ensures longitudinal linear ow (Fig. 45.4b).

Salvage ‘composite grafts’

ese should be constructed ‘electively’ when it can be predicted that the main gra will not reach the aorta. e reach of the main recipient gra should be established by lling the heart, and by considering the location of the ascending thoracic aorta when the pericardium was rst opened. e ‘shortfall’ can be measured accurately and a proximal gra extension can be added (Fig. 45.5).

One cannot overemphasize the need to perform these manoeuvres in a pre- emptive manner rather aer the realization that a gra is too short. However, if that situation is encountered and a gra is short when the heart is full, it should be extended imme-

the LITA, nor create a ‘ow steal’ scenario from the LITA– LAD gra. e gra ows and pulsatility index should be checked.

ese extensions can be performed with a further short period of aortic clamping and cardioplegia (which we prefer) or by an aortic partial occlusion clamp (which many surgeons still use). Alternatively, the proximal anastomosis can be created on the ascending aorta with a clampless facilitating device, such as the Heartstring® (Getinge, Sweden). is short period of additional time is safe and uniformly leads to a superior haemodynamic result and enhanced gra patency.

Conclusion

Composite gras allow versatility, wider deployment, especially of arterial gras, ecient conduit use, and help to overcome dicult anatomical situations. Ideally, the composite, gra- to- gra anastomosis should be performed close to the surface with a stable platform, and an immobilized recipient gra, and the anastomosis tied down with the gras under arterial pressures, to avoid any pursestring eect. e composite anastomosis should be constructed in an identical manner to that which surgeons use routinely for any vascular anastomosis. One should never hesitate to extend a gra that does not reach the aorta comfortably.

diately rather than compromise the distal anastomosis. Oen only 3– 4cm of any suitable residual conduit is needed or by harvesting 4– 6cm of saphenous vein.

e gra- to- gra extension anastomosis is usually end- to- end with widely spatulated adjacent anastomotic ends. Such anastomoses are readily accomplished, as on the le side, if required, they are near the pulmonary trunk, and on the right side, near the right atrial appendage. e proximal anastomosis is then constructed on the ascending thoracic aorta as usual. e end- to- end gra- to- gra suture line is tied when the gras are lled and pressurized aer the release of the aortic clamp to ensure there is no bleeding, and to safeguard against purse- stringing.

e inow to a short gra may also be via an end- to- side anastomosis to the body of another gra on the same side of the heart.

In a ‘salvage’ situation, a short le- sided gra may also be anastomosed to the LITA. However, great care is required not to damage

Fig.45.5 Proximal extension of a short radial artery (RA) graft.

REFERENCES

1. Tector AJ, Amundsen S, Schmahal TM, Kress DC, Peter M. Total revascularization with T grafts. Ann Thorac Surg. 1994;57(1):33– 9.

2. Buxton BF, Shi WY, Tatoulis J, Fuller JA, Rosalion A, Hayward PA. Total arterial revascularization with internal thoracic and radial artery gras in triple vessel coronary artery disease is associated with improved survival. J orac Cardiovasc Surg. 2014;148(4):1238– 44.

3. Calaore AM, Di Giammarco GG, Luchiani N, Maddestria N, Di Nardo E, Angelini G. Composite arterial conduits for a wider arterial myocardial revascularisation. Ann orac Surg. 1994;58(1):158– 90.

4. Glineur D, D’hoore W, Price J, Dormeus S, De Kerchove L, Dion R, etal. Survival benet of multiple arterial graing in a 25- year single institutional experience:the importance of the third arterial gra. Eur J Cardiothorac Surg. 2012;42(2):284– 91.

5. Vallely MP, Edelman JJ, Wilson MK. Bilateral internal mammary arteries; evidence and technical considerations. Ann Cardiothorac Surg. 2013;2(4):570– 7.

6. Gaudino M, Di Mauro M, Iaco AL. Immediate ow reserve of Y thoracic artery gras:an intraoperative ow metric study. J orac Cardiovasc Surg. 2003;126(4):1076– 9.

7. Tatoulis J, Wynne R, Skillington PD, Buxton BF. Total arterial revascularization:achievable and prognostically eective— a multicentre analysis. Ann orac Surg. 2015;100(4):1268– 75.

8. Robinson BM, Paterson HS, Naidoo R, Dhurandhr V, Denniss AR. Bilateral internal thoracic artery composite Y gras:analysis of 464 angiograms in 296 patients. Ann orac Surg. 2016;101(3):974– 80.

9. Maniar HS, Barner HB, Bailey MS, Prasad SM, Moon MR, Pasque MK, etal. Radial artery patencies:are aorta coronary conduits superior to composite graing? Ann orac Surg. 2003;76(5):1498– 503.

SECTION 7 Technical aspects ofcoronary artery bypass graft surgery332

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10. Glineur D, Hanet C, D’hoore W, Poncelet A, De Kerchove L, Etiernne P. Causes of non- functioning right internal mammary used in AY- gra conguration:insights from a 6- month systematic angiographic trial. Eur J Cardiothorac Surg. 2009;36(1):129– 35.

11. Pevni D, Mohr R, Paz Y, Kramer A, Ben- Gal Y, Nesher N, etal Long- term outcome of revascularization with composite T- gras:is bilateral mammary better than single mammary

and radial artery graing? J orac Cardiovasc Surg. 2016;151(5):1311– 9.

12. Kim KB, Hwang HY, Hahn S, Kim JS, Oh SJ. A randomised comparison of the Saphenous Vein Versus Right Internal oracic Artery as a Y Composite Gra (SAVE RITA) trial:one year angiographic results and mid- term clinical outcomes. J orac Cardiovasc Surg. 2014;148(3):901– 8.

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Sequential coronarygraing

Juan B. Grau, Jacqueline H. Fortier, and David Glineur

Introduction

e benets of coronary artery bypass graing (CABG) are directly correlated with the patency of the bypass gras and the degree to which the myocardium is revascularized, and both of these areas have been subject to much research over the past few decades.

Sequential distal graing is a surgical technique in which a single conduit has two or more distal anastomosis for a single proximal anastomosis; in situ sequential arterial gras may have no proximal anastomosis. Proponents of this method suggest that there is increased total gra ow due to improved distal runo in sequential gras, which leads to better gra patency over time. ey also suggest that sequential graing is more ecient in terms of conduit use, and reduces the amount of aortic manipulation during surgery.

Despite these purported benets, sequential graing has not been consistently adopted by cardiac surgeons. Critics argue that a proximal occlusion of a sequential gra would be catastrophic for a patient, as the common inow could put numerous myocardial territories at risk. is has been the principal deterrent against the wider use of sequential graing, although there are also concerns about increased manipulation of the conduit, the technical complexity of some side- to- side anastomoses, and diculty with the lie of the conduit. ere is also concern about competitive ow, which occurs when the ow through the stenosed native coronary artery competes with the ow through the bypass conduit. e reduced ow can cause the bypass conduit to constrict and fail. is phenomenon and its implications are discussed in further detail later in this chapter in ‘Sequential arterial graing and competitive ow’.

Despite these concerns, the reality is that cardiothoracic surgeons are increasingly operating on patients with diuse coronary artery disease or for repeat CABG. In both cases, the ecient use of available conduits, which may include the use of sequential gras, can help maximize myocardial revascularization. Prior to adopting a sequential graing technique, however, the available evidence supporting and opposing its use should be considered. is chapter provides an overview of the available literature on the subject of sequential graing with both arterial and venous conduits, with a particular focus on gra patency, gra ow, and long- term clinical outcomes.

Sequential grafting and graftﬂow

Venousgrafting

In a study by Kim and colleagues, the inuence of bypass graing techniques on ow through saphenous vein gras (SVGs) was assessed. e authors compared a total of 328 gras, 84 of which were sequential, and prospectively measured intraoperative ow characteristics. Sequential gras had a higher mean ow than individual gras (49.4 vs 37.1 mL/ min; P <0.001), and there was a positive correlation between mean ow and an increase in the number of anastomoses per gra (P <0.001).

Another study by Nordgaard and colleagues examined the mean blood ow and pulsatility index of saphenous vein gras in 581 patients. Patients were analysed based on whether the conduit provided single (i.e. non- sequential), double, or triple distal anastomoses. ere was no dierence between ow of gras to dierent target vessels except to the diagonals, which had signicantly lower ow than the obtuse marginals (P <0.001), the posterior descending artery (P=0.035), or the right coronary artery (P=0.003). ere appeared to be a dose– response relationship between mean blood ow and the number of distal anastomoses; vein gras with a single distal anastomosis had signicantly lower ow than sequential gras, and sequential gras with two distal anastomoses had signicantly lower ows than sequential gras with three distal anastomoses (P=0.017). e authors also observed higher ows in men than in women (P <0.001). When comparing the dierent coronary territories, there was a lower mean pulsatility index in SVGs on the le than the right coronary (2.0 ± 0.01 vs 2.4 ± 0.06; P <0.001). ere was, however, no signicant dierence in mean pulsatility index between sexes, the number of distal anastomoses, or between the groups of vein gras within each coronary system. e authors concluded that vein gras with more distal anastomoses had higher blood ow rates, that men had higher ows than women, and that single SVGs to the diagonals had the lowest ow.

Arterialgrafting

A study by Nakajima and colleagues reported on the results of 633 patients who underwent CABG with only arterial gras. Atotal of 2617 gras were included in the analysis, and patients were separated based on whether they had an in situ single ITA with a composite

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radial artery (ITA plus RA) or in situ bilateral ITA (BITA). e groups were further subdivided depending on the number of distal anastomoses. e authors observed that antegrade ow was higher in the BITA group compared to the ITA plus RA group (P=0.02). Gra ow at the proximal end of the in situ ITA was signicantly higher in the BITA group than in the ITA plus RA group (79 ± 35 vs 53 ± 31 mL/ min; P <0.0001). e incidence of competitive ow was comparable regardless of the number of distal anastomoses. Among the sequential gras, the ow in gras anastomosed to ve or more coronary branches was signicantly higher than gras serving only three coronary branches (81 ± 35 vs 67 ± 30 mL/ min; P=0.01). e authors concluded that sequential and composite arterial graing with ITA plus RA was a reliable and safe revascularization technique, and that BITA would be feasible for patients with multivessel disease due to the reduced risk of competitive ow and higher overall bypass ow.

average of 55months post CABG. At the time of the early, standardof- care angiogram, 98.0% of gras were patent, 91.5% had antegrade ow, and competitive ow was detected in 6.5% of gras. Over time, gras with antegrade ow were signicantly more likely to remain patent than gras with competitive ow (87.9% at 5years and

71.3% at 8years, vs 25.8% at 5years and 9.2% at 8years; P <0.0001). Signicant predictors of competitive ow from the target were a right coronary artery target (odds ratio (OR) 2.20; P=0.0002), anastomoses present at the distal end of the gra (OR=2.90; P=0.0003), and the use of a composite RA (OR=1.90; P=0.03). Importantly, non- sequential graing was inversely correlated with the incidence of competitive ow (OR=0.48; P=0.04). e authors concluded that competitive ow can be avoided by considering each patient’s coronary anatomy and carefully selecting the optimal conguration for sequential graing. In their opinion, selection of the target of the gra end is crucial to ensure antegrade bypass ow and improve the chances of long- term patency of the sequential bypass gras.

Sequential grafting andpatency

Venouspatency

A meta- analysis of 12 studies by Li etal. reviewed patency rates in sequential versus non- sequential SVGs. In their analysis, they found that the risk of SVG occlusion was lower in sequential versus non- sequential gras (risk ratio (RR) 0.67, 95% condence interval (CI) 0.60– 0.74), and that occlusion was less common in side- toside anastomoses than end- to- side anastomoses (RR 0.52, 95% CI

0.34– 0.80). ey did not nd a signicant dierence in the rates of occlusion between sequential and non- sequential SVG in distal endto- side anastomoses (RR 0.85, 95% CI 0.68– 1.06).

Arterialpatency

In a prospective, randomized trial, Glineur and colleagues compared the patency of BITA used in situ versus in a Y- gra conguration among 304 randomized patients. e right ITA (RITA) was used in situ posterior to the aorta through the transverse sinus with only one anastomosis per RITA. Gra patency was assessed clinically and by angiogram at 6months and 3years post CABG. At 6months, the observed ITA anastomotic patency rate was 97% in both groups (P=0.99). e sequential patency of the RITA was not dierent than the patency of the in situ RITA with only one distal anastomosis. At 3years post CABG, angiographic follow- up was 75% complete. e authors did not nd a signicant dierence in the percentage of patent ITA gras between the in situ group and the Y composite group (LITA:98.2% vs 97.2%; P=0.96 and RITA:93% vs 96.5%; P=0.1). ey did not nd a dierence in the patency of the distal anastomoses between the in situ group and Y composite group (LITA: 98.2% vs 96.8%; P=0.96 and RITA:93% vs 94.5%; P=0.81). e patency of the RITA with sequential distal anastomoses at 3years was also not dierent than the patency of the RITA used in situ.

Nakajima and colleagues conducted a long- term follow- up of 3263 bypass gras in 852 patients who underwent o- pump CABG with arterial gras over a 10- year period. All patients received ITA and RA gras, and an angiogram was performed approximately 2 weeks aer surgery as part of that centre’s standard of care. e authors reviewed clinical records for all patients, and completed followup angiograms for 561 bypass gras in 157 of those patients at an

e same group of researchers completed another study evaluating ow distribution in sequential and composite arterial gras for triple- vessel disease. Atotal of 2514 gras in 601 patients with triple- vessel disease who underwent o- pump CABG using the LITA in situ to bypass the le anterior descending artery (LAD), and a composite RA to bypass the le circumex and right coronary artery. e authors once again used their centre’s standard- of- care angiograms, completed 2- weeks post CABG, and 111 patients with 443 bypass gras underwent a second, follow- up angiogram at an average of 54months post CABG. e ow through the conduits was graded as either antegrade, competitive, or no ow. In the early (2- week) angiogram, 98.1% of gras were patent, and 6.4% were determined to have competitive ow. Individual and sequential in situ ITA gras had a lower incidence of competitive ow than composite gras (0.3% vs 7.6%; P <0.0001). For RA used to bypass non- LAD territories, the majority of the competitive ow (86.3%) was detected at the distal end of the I- or Y- gra. In this study, there was no association between the number of sequential anastomoses and patency rates (P=0.09). For composite Y- gras, antegrade ow was more common (95.7%) when both the LAD and right coronary artery had 76– 100% stenoses; when the right coronary artery stenosis was graded between 51% and 75%, only 78.1% of gras had antegrade ow (P <0.0001). e authors concluded that, in appropriately selected situations, sequential and composite graing were reliable and safe techniques. ey also noted that patency of the Y- gra to the three dierent coronary territories was dependent on a balanced ow towards the LAD and right coronary regions.

Dion and colleagues studied the patency of ITA graing among the rst 500 patients who received at least one sequential ITA gra between October 1985 and August 1991 at Cliniques Universitaires St Luc, Brussels, Belgium. Of this cohort of patients, 161 agreed to a follow- up angiogram, which was performed at an average of

7.4years aer surgery. Overall, 95.5% of the arterial anastomoses were patent and 96.1% of the sequential ITA were patent. Although there was a signicant dierence between the patency rate of in situ ITA and free ITA anastomoses (96.3% vs 86.5%; P=0.02), when the sequentials covered the proximal circumex and the LAD territory, the patency rates were similar to an in situ, non- sequential LITA. When the sequential graing included the distal branches of the circumex artery or the right coronary territory, a drop of patency to 85% was observed. Sequential anastomoses constructed in

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a side- to- side manner had a better patency rate than the diamondshaped ones:97.2 versus 91.5% (P=0.004).

Ohira etal. analysed the long- term outcomes of 452 patients who underwent CABG with in situ BITA graing to the le coronary artery. ey divided the population in two groups:191 in the sequential group with the LITA on the lateral wall of the heart, and 261 in the non- sequential group. ey propensity- matched 147 pairs, and performed early gra evaluation in 78.6% of patients. Five complications occurred in the distal segment of the sequential LITA gra (two occlusions, two string signs, and one case of competitive ow), and three complications occurred in the non- sequential group (two occlusions, and one string sign). Event- free anastomosis patency rates were 97.8% in the sequential group and 97.4% in the individual group (P=0.85). When performing sequential anastomosis with the

upon these results, the authors propose that sequential graing with the RA was a safe method to maximize arterial revascularization, and was associated with an excellent 10- year survival rate.

Ohira et al. analysed the long- term outcomes of 452 patients undergoing CABG with BITAs to the le circumex. e initial two groups, consisting of 191 patients in the sequential group and 261 patients in the individual group, were propensity- matched to 147 pairs. At 8years post CABG, 94.6% of patients in the sequential and 96.3% of patients in the non- sequential group were free from target lesion revascularization, and the survival rates were 80.7% and 77.4%, respectively. e conclusion of this article was that the utilization of the LITA as the single conduit for multiple sequential anastomoses to the lateral wall provided excellent survival and freedom from repeat revascularization.

LITA in situ, the authors found that the best patency rate was observed when the rst sequential of the LITA onto the lateral wall was done using a diamond, rather than a parallel, anastomosis. is

Sequential arterial grafting and competitiveﬂow

patency refers not only to the rst diamond- shaped anastomosis, but also to the distal end of the conduit. is study demonstrated the safety of in situ sequential LITA graing to the lateral wall.

As mentioned previously, competitive ow occurs when the residual ow through the native coronary artery competes with the ow through the bypass conduit. e most important factors that deter-

Sequential grafting and long- term major adverse cardiac and cerebrovascularevents

mine whether a given conduit is at risk for competitive ow are the degree of stenosis through the native coronary artery, and the diameter and length of the bypass gra.

Competitive ow is rarely a concern with SVGs, as they are cap-

Ouzounian and colleagues performed a single- centre study evaluating the rates of adverse events of patients with triple- vessel disease who underwent rst- time, isolated, on- pump CABG between 1995 and 2005. Patients received a LITA to the anterior wall and vein gras to the lateral and posterior walls. e patients were further stratied based on whether they had sequential or nonsequential graing of the vein to the posterolateral walls. e authors examined the rates of mortality, readmission to hospital, and in- hospital adverse events for a median follow- up of 78months. Aer adjusting for dierences in baseline acuity and systolic function, they found no signicant dierences in adverse event rates between patients who received sequential versus non- sequential use of the vein gra.

Glineur and colleagues compared the long- term major adverse cardiac and cerebrovascular events (MACCE) rates of BITA graing in situ versus Y composite graing in a randomized trial. ey found that more coronary targets were able to be revascularized using BITA in patients randomized to Y- graing, with multiple sequential anastomosis on the lateral wall, versus in situ when only one anastomosis was constructed with the RITA (3.2 vs 2.4 arteries/ patient; P <0.01). Although there were no signicant dierences in the rates of in- hospital morbidity or mortality, myocardial infarction, stroke, or late survival between the groups, there was a signicant increase in MACCE endpoints in the in situ group 7years post CABG. is may be due to vein gra failure, as patients in the in situ group had the remaining posterolateral wall branches graed with veins, rather than with the single RITA.

Schwann and colleagues analysed the 10- year survival of sequential RA gras for multivessel CABG. ey compared late survival of patients receiving sequential RA gras (532 patients) versus patients receiving one ITA with SVGs (4131 patients). e risk- adjusted rate of survival at 10years was signicantly higher in the sequential RA group than in the ITA and SVG group (RR 0.61; P=0.003). Based

acitance vessels that have the ability to maintain ow despite competition from the native coronary artery. Arterial bypasses, on the other hand, don’t have the ability to adapt to competition from the native coronary arteries, resulting in the presence of a string sign or, in some cases, occlusion of the bypass gra.

Another factor that aects the presence or absence of competitive ow is the length of the conduit gra. When Y constructs are utilized, this is of particular relevance. e areas of higher risk for competitive ow will be the most distal areas of the Y construct, and the most distal branches of the coronary tree, especially distal branches of the right coronary artery.

Individual versus sequential graing techniques vary in their potential for competitive ow, independent of the degree of stenosis of the coronary target or targets. is is due to phasic delay between the pressure waves in the gras. Individual, or non- sequential, gras have only two points of interaction:the proximal inow and the distal outow. In sequential graing, however, the interactions include the proximal anastomotic site and each one of the sequential anastomoses of the gra, as well as the run- o. Put another way, in an individual gra, the potential for competitive ow arises from only one coronary target, while in a sequential gra there is potential for competitive ow from multiple targets.

Today, the success of CABG is measured not only by outcomes such as survival, the absence of MACCE, and freedom from reintervention, but also by patency. Decades ago, when SVGs were both the predominant and the preferred conduit, the patency of the gra was determined simply by whether it was angiographically open (patent), narrowed (stenosed), or closed (occluded). Today, the increasing use of arterial conduits has forced the evolution of the concept of patency, to include not only angiographic patency but also the function of the gra, measured by fractional ow reserve and other techniques. is evolution reects the vasomotor properties that are present in arterial gras, but absent in veins.

SECTION 7 Technical aspects ofcoronary artery bypass graft surgery336

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When a surgeon uses arterial graing in a sequential manner, many factors will aect the patency and long- term outcomes aer CABG, including the quality of the run- o, the degree of stenosis of the target vessels, and the type of arterial conduit used. If, in addition to the previously described factors, multiple sequential distal anastomoses are included, then the complexity and lack of predictability of gra survival become greater. Our recommendations to clinicians performing sequential graing are as follows.

• If using arterial conduits, ensure a degree of stenosis greater than

60– 70% with excellent run- o and quality of the target.

• Refrain from graing low– moderate lesions (50– 60%) with ar-

terial gras, especially when the moderately stenosed vessel is the

most distal anastomosis of a sequential gra.

• Either through a Y conguration (bilateral mammary) or any

other approach (T- gra), ensure adequate length of the two limbs

to avoiding kinking.

• If the arterial conduits are very small in size, multiple sequential

anastomoses are not recommended due to the increased risk of

technical diculties.

• When in doubt about the degree of stenosis of a coronary artery,

functional assessment by fractional ow reserve should be per-

formed prior to surgery, especially if full arterial revascularization

with multiple sequential bypasses is planned.

Only through adherence to these principles can optimal outcomes be achieved.

REFERENCES

1. Kim JH, Lee Ty, Kim JB, Cho WC, Jung SH, Chung CH, etal. e impact of sequential versus single anastomoses on ow characteristics and mid- term patency of saphenous vein gras in coronary bypass graing. J orac Cardiovasc Surg. 2011;141(3):750– 4.

2. Nordgaard H, Vitale N, Haaverstad R. Transit- time blood ow measurements in sequential saphenous coronary artery bypass gras. Ann orac Surg. 2009;87(5):1409– 15.

3. Nakajima H, Kobayashi J, Toda K, Fujita T, Iba Y, Shimahara Y, etal. Safety and ecacy of sequential and composite arterial graing to more than ve coronary branches in o- pump coronary revascularisation:assessment of intra- operative and angiographic bypass ow. Eur J Cardiothorac Surg. 2010;37(1):94– 9.

4. Li J, Liu Y, Zheng J, Bai T, Liu Y, Wang X, etal. e patency of sequential and individual vein coronary bypass gras:a systematic review. Ann orac Surg. 2011;92(4):1292– 8.

5. Glineur D, Hanet C, Poncelet A, D’hoore W, Funken JC, Rubay J, etal. Comparison of bilateral internal thoracic artery revascularization using in situ or Y gra congurations:a prospective randomized clinical, functional, and angiographic midterm evaluation. Circulation. 2008;118(14 Suppl):S216– 21.

6. Nakajima H, Kobayashi J, Toda K, Fujita T, Shimahara Y, Kashara Y, etal. A 10- year angiographic follow- up of competitive ow in sequential and composite arterial gras. Eur J Cardiothorac Surg. 2011;40(2):399– 404.

7. Nakajima H, Kobayashi J, Toda K, Fujita T, Shimahara Y, Kasahara Y, etal. Angiographic evaluation of ow distribution in sequential and composite arterial gras for three vessel disease. Eur J Cardiothorac Surg. 2012;41(4):763– 9.

8. Dion R, Glineur D, Derouck D, Verhelst R, Noirhomme P, El Khoury G, etal. Long- term clinical and angiographic follow- up of sequential internal thoracic artery graing. Eur J Cardiothorac Surg. 2000;17(4):407– 14.

9. Ohira S, Doi K, Okawa K, Dohi M, Yamamoto T, Kawajiri H, etal. Safety and ecacy of sequential le internal thoracic artery graing to le circumex area. Ann orac Surg. 2016;102(3):766– 73.

10. Ouzounian M, Hassan A, Yip AM, Buth KJ, Baskett RJ, Ali IS,

etal. e impact of sequential graing on clinical outcomes following coronary artery bypass graing. Eur J Cardiothorac Surg. 2010;38(5):579– 84.

11. Glineur D, Boodhwani M, Hanet C, de Kerchove L, Navarra E,

Astarci P, etal. Bilateral internal thoracic artery conguration for coronary artery bypass surgery:a prospective randomized trial. Circ Cardiovasc Interv. 2016;9(7):e003518.

12. Schwann TA, Zacharias A, Riordan CJ, Durham SJ, Shah AS,

Habib RH. Sequential radial artery gras for multivessel coronary artery bypass gra surgery:10- year survival and angiography results. Ann orac Surg. 2009;88(1):31– 9.

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Oﬀ-pump coronary artery bypassgraing

Tips and tricks

Gianluca Torregrossa, David P. Taggart, and John D. Puskas

Introduction

O- pump coronary artery bypass graing (OPCAB) is a highly specialized technique with the potential for reduction of in- hospital morbidity and mortality, particularly in high- risk patient populations. When possible, it should be performed as a clampless or noaortic- touch (NAT) technique with multiple or all- arterial conduits. By optimizing longevity of gra patency with arterial conduits and minimizing the risk of perioperative stroke by minimizing aortic manipulation, clampless and NAT OPCAB techniques may be considered the ideal form of surgical coronary revascularization.

is is a time- consuming and technically challenging operation that requires dedicated acquisition of individual and team skills beyond those necessary for on- pump CABG. It is not for every surgical team, nor for every patient. e major drawback of OPCAB is its greater technical diculty, requiring judicious navigation of a learning curve for the entire surgical team. e surgeon should be familiar with stabilization techniques, know how to handle haemodynamic changes during cardiac displacement, and know how to deal with the ischaemic sequelae of temporary coronary occlusion to prevent bailout situations. Considerable experience with traditional cardiac surgery is required. Importantly, OPCAB is only justied if the quality of anastomoses and completeness of revascularization are not compromised.

e aim of this chapter is to provide a review of tips and tricks for OPCAB that summarize the overall experience of the senior authors with this technique in order to facilitate the learning curve for surgeons who wish to add OPCAB to their surgical armamentarium.

Preparation

Aer the induction of anaesthesia, patients are positioned, prepped, and draped in an identical fashion to an on- pump procedure. Amedian sternotomy may be routinely accomplished via a limited skin incision (10– 12 cm) that allows the surgeon to visualize the operative eld from an orientation that is similar to on- pump procedures. is facilitates target- vessel identication as well as harvesting of the

internal thoracic arteries for use as conduits. Additionally, should conversion to conventional bypass become necessary, a median sternotomy allows easy access to cannulate for cardiopulmonary bypass. Isolated graing of specic individual vessels can be performed using a variation of le mini- thoracotomy, anterior for the le anterior descending artery (LAD) or lateral for access to the marginal vessels.

Conduitharvesting

During le internal thoracic artery (LITA) harvest we routinely skeletonize the vessel using the Harmonic® scalpel (Harmonic Synergy® Blade, Ethicon, Somerville, NJ, USA) in order to optimize the length of the vessel while minimizing trauma to both the conduit and chest wall. Unlike on- pump CABG, in OPCAB the heart is not decompressed and a fully harvested LITA length is oen necessary to avoid tension on the LITA– LAD anastomosis during rightward displacement necessary for lateral or inferolateral wall graing. Dividing or removing the endothoracic fascia, skeletonizing the internal thoracic artery (ITA) during harvest, and dividing the le pericardium vertically towards the le phrenic nerve at the level of the pulmonary artery all provide for extra length and less tension on the LITA– LAD anastomosis. Aer dividing the thoracic artery we inject it using a so silastic- tipped needle, with a solution composed by 10 mL of blood, 1 mg of milrinone (in a concentration of 1 mg/ mL), 9 mL of buered crystalloid (Plasma- Lyte®), and 1 mL of heparin (1000 U/ mL solution). e instillation of approximately 5 mL of this solution into the lumen of each ITA pharmacologically resolves any spasm, thereby creating an ideal conduit for bypass. Some other surgeons avoid intraluminal injections and prefer to wrap the skeletonized ITA in a sponge bathed in topical vasodilators, such as papaverine. is is also eective. Permissive hypertension aer ITA harvest also helps to dilate the ITA conduits prior to graing.

Radial artery and saphenous vein conduits are harvested endoscopically and simultaneously during ITA harvest. It is our practice to administer 2500 U of heparin before beginning endoscopic vein harvest to minimize thrombus formation within the conduit during the harvest, but otherwise do not give full- dose systemic heparin until

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