Reusing the patent internal mammary artery as a conduit in redo coronary artery bypass surgery

Abstract

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was, in patients with previous internal mammary artery/internal thoracic artery (ITA) grafts, can the internal mammary artery/ITA be reused/recycled in redo coronary artery bypass surgery? Fourteen papers were found using the reported search of which 10 represented the best evidence to answer the clinical question. There was variation in patient selection, the number of patients reported, outcome measures recorded, and methods and duration of follow-up. The results were mostly in favour of using a recycled ITA when it could be safely harvested. Most studies were retrospective. One large series of 60 patients who underwent redo coronary artery bypass grafting (CABG) using previously implanted ITAs had a mean time to reoperation of 117 ± 68 months. They reported no operative deaths; no patients required further or subsequent target vessel revascularization; 30-day mortality was 8.3% and myocardial infarction rate was 3%. Another two series of 16 and 12 patients underwent recycling of arterial grafts during coronary artery revascularization with no perioperative deaths in either. Postoperative angiography was performed in 10 patients in one of these studies, which showed excellent flow in all redone left internal thoracic artery (LITA) grafts. One study reported results from a prospective cohort of 9 patients who underwent redo coronary artery bypass grafting. Interval between operations was between 1 and 132 months. There was no perioperative mortality, but 1 patient required reintervention (to an interposition vein graft). A further study of 4 patients who underwent redo CABG using ITAs that were patent but with severe stenosis at the distal anastomosis had no mortality. Postoperative angiography showed patency of all grafts. There have also been 4 case reports on reusing the ITA/ITA in redo CABG with no damage to the reused LITA, no perioperative mortality and satisfactory follow-up at up to 29 months. Evidently, the recycled ITA can be used in redo coronary artery bypass grafting. Papers found were retrospective series or case reports. As such, there is no direct comparison in outcomes between the recycled ITA and first-time ITA harvest or any other conduit for CABG. In conclusion, we find that when it is possible to harvest a previously used ITA, studies have shown it to be a safe and viable conduit in redo CABG with good long-term outcomes.

INTRODUCTION

A best evidence topic was constructed according to a structured protocol. This is fully described in the ICVTS [1].

THREE-PART QUESTION

In patients with patent [internal mammary artery/internal thoracic artery grafts] can [the internal mammary artery/internal thoracic artery] be [re-used/recycled in re-do coronary artery bypass surgery]?

CLINICAL SCENARIO

A 73-year old man presented with acute coronary syndrome 17 years after coronary artery bypass grafting (CABG) × 5 including left internal thoracic artery (LITA) to left anterior descending (LAD). Flow was demonstrated on angiography in the LITA with significant stenosis at the distal anastomosis with the LAD. The LAD distal to the stenosis was a suitable target for re-grafting. The multidisciplinary team meeting for high-risk cardiac patients discussed the possibility of re-anastomosing the patent left internal mammary artery on the distal LAD. We resolved to check the evidence for recycling the LITA/LITA for redo CABG.

SEARCH STRATEGY

Medline 1950 to April 2015 using OVID interface (re-use OR re-used OR Recycle OR recycled OR recycling OR reuse) AND (internal thoracic artery.mp OR internal mammary artery.mp or Mammary Arteries/).

SEARCH OUTCOME

Fourteen papers were found using the reported search and 10 represented the best evidence to answer the clinical question. These papers are presented in Table 1.

Table 1:

Best evidence papers

Author, date, journal and country, Study type (level of evidence)	Patient group	Outcomes	Key results	Comments
El Oumeiri et al. (2011), Ann Thorac Surg, Belgium [2] Retrospective review (level 3b)	April 1996–February 2009 Single-centre experience 60 patients underwent redo CABG using previously implanted internal thoracic arteries Mean age 64 ± 9 years Mean time to reoperation 117 ± 68 months Mean follow-up 60 ± 36 months	Operative mortality 30-day mortality, (n = 5) Mean postoperative hospital stay MI LITA injury Postoperative complications Patients requiring target vessel revascularization	0% 8.3% 3.4 ± 9.2 days 3% 0% 25% 0%	Included on- and off-pump cases
Noirhomme et al. (1999), Ann Thorac Surg, Belgium [3] Prospective study (level 2B)	February 1994–July 1997 16 patients underwent recycling of arterial grafts (70% used recycled arterial grafts exclusively) Mean interval from primary to reoperation 8.5 years (range 3–12 years) Follow-up 13 months (range 2–43 months)	Operative mortality 30-day mortality Mean postoperative hospital stay MI LITA injury Postoperative complications Patients requiring target vessel revascularization	0% 0% 14 days (range 10–28) 6.2% 0% 3 patients required intra-aortic balloon pump to aid weaning off cardiopulmonary bypass 3 patients required inotropic support during weaning 0%	9 of 10 patients had a negative exercise stress test result at 3 months
Pasic et al. (2005), J Thorac Cardiovasc Surg, Germany [4] Prospective cohort study (level 2b)	1997–2003 12 patients underwent repeat harvesting of the LITA during redo CABG Mean age 64 ± 7 years Reimplantation of the LITA was performed 6 months to 11 years after the original operation. Mean 4.3 ± 3 years Mean follow-up postintervention was 4.4 ± 2.4 years (4 months to 7 years)	Operative mortality 30-day mortality MI LITA injury Postoperative complications Patients requiring target vessel revascularization	0% 0% 0% 0% 0% 0%	Postoperative angiography performed in 10 patients (2 patients refused as they had no symptoms) Excellent flow in all patent LITA grafts
Agrifoglio et al. (2007), J Thorac Cardiovasc Surg, Italy [5] Prospective study (level 2b)	January 1990–December 2005 Single-centre experience 9 patients underwent redo CABG using previously implanted internal thoracic arteries (5 patients had anastomotic site stenosis and 4 patients had progression of native coronary disease) Mean interval between operations was 27.7 ± 42.3 months (range 1–132 months) Mean age 59.3 ± 13.3 years	Operative mortality 30-day mortality MI LITA injury Patients requiring target vessel revascularization	0% 0% 0% 0% One patient had coronary artery angioplasty at follow-up	15-year freedom from restenosis of recycled ITA graft was 75.0 ± 21.7% Survival at 15 years was 83.3 ± 15.2% (1 patient died from non-cardiac causes) However, the restenosis was located between the ITA and an interposed saphenous vein graft
Noyez and Lacquet (1993), Ann Thorac Surg, Netherlands [6] Retrospective review (level 3b)	January 1987–December 1992 5 patients underwent coronary artery revascularization by reusing the LIMA Mean age at reoperation 63 ± 8 years Mean interval between the first operation and reoperation was 51.6 ± 28.1 months Follow-up ranging from 5 months to 4 years after reoperation	Operative mortality 30-day mortality MI LITA injury Patients requiring target vessel revascularization	0% 0% 0% 0% 0%	Postoperative re-evaluation treadmill test was 80% negative
Antona et al. (1996), Ann Thorac Surg, Italy [7] Prospective cohort (level 2b)	1990–1993 4 patients underwent coronary artery reoperation using internal mammary arteries that were patent but severely stenotic 3 of 4 patients had an LITA recycled Mean age at reoperation 50 ± 13 years Interval between operations 14 ± 15 months	Operative mortality 30-day mortality MI LITA injury Patients requiring target vessel revascularization	0% 0% 0% 0% 0%	Early results Graft reinvestigation at 15 days showed patency without stenoses in all ITA grafts Angiographic evaluation at 7 and 35 months showed patency of all reused grafts without the presence of stenoses
Dohi et al. (2014), Ann Thorac Surg, Japan [8] Case report (level 5)	70-year old man had CABG 17 years previously using a LITA to the LAD The LITA was patent but 75% stenosed at the anastomotic site on coronary angiogram LITA recycled and anastomosed to the circumflex artery and the right internal thoracic artery was anastomosed to the LAD	Operative mortality 30-day mortality MI LITA injury Patients requiring target vessel revascularization	0% 0% 0% 0% 0%	CT angiogram showed that all grafts were patent on postoperative day 10 All grafts remained patent at 2 years on CT angiogram
Uwabe et al. (2000), J Cardiovasc Surg (Torino), Japan [9] Case report (level 5)	41-year old male Previous (MIDCAB) LITA to LAD 4 months earlier Poor-controlled hypercholesterolaemia Coronary angiogram showed stenoses of the left main trunk and anastomosis site of the LITA At redo operation, LITA skeletonized and reused in situ to the LAD	Operative mortality 30-day mortality MI LITA injury Patients requiring target vessel revascularization	0% 0% 0% 0% 0%	Patient doing well at 18 months after surgery
Vivirito et al. (2015), Tex Heart Inst J, Italy [10] Case report (level 5)	62-year old male Previous CABG × 4 13 years earlier including free LITA to LAD graft Coronary angiogram showed occlusion of all grafts Critical stenosis on LAD just distal to free LITA–LAD anastomosis Reimplantation of skeletonized LITA distal to stenosed LAD Patient also required 3 × vein grafts and mitral valve replacement	Operative mortality 30-day mortality MI LITA injury Patients requiring target vessel revascularization	0% 0% 0% 0% 0%	Patient doing well at 29 months after surgery
Scioti et al. (1999), Tex Heart Inst J, Italy [11] Case report (level 5)	57-year old man Previous CABG 2 months earlier Coronary angiography revealed a 90% occlusion of the LITA–LAD anastomosis, Reimplantation of LITA distal to stenosis	Operative mortality 30-day mortality MI LITA injury Patients requiring target vessel revascularization	0% 0% 0% 0% 0%	One-year follow-up with Doppler echocardiography and coronary angiography showed patency of the recycled graft

CABG: coronary artery bypass grafting; LIMA: left internal mammary artery; LAD: left anterior descending; MI: myocardial infarction; LITA: left internal thoracic artery; CT: computed tomography; MIDCAB: minimal access coronary bypass surgery.

RESULTS

El Oumeiri et al. [2] have published a large retrospective series of 60 patients who underwent redo CABG using previously implanted ITAs. Using a variety of operative techniques, patients had redo surgery with a mean time to reoperation of 117 ± 68 months. There were no operative deaths and no patients required further or subsequent target vessel revascularization. Freedom from death was 93% at 1 year and 85% at 5 years; freedom from major cardiac events was 93% at 1 year and 81% at 5 years. The study concluded that in selected patients, recycling of ITA grafts during reoperative CABG was safe and feasible, on and off-pump. This was seen to be an option where there was a lack of alternative conduit or to avoid use of saphenous vein as a conduit.

Noirhomme et al. [3] reported on 16 patients who underwent recycling of arterial grafts during coronary artery revascularization (70% used recycled arterial grafts exclusively). The mean interval from primary to reoperation was 8.5 years (range 3–12 years) and follow-up ranged between 2 and 43 months. Eleven patients had a patent internal mammary artery graft used as the recipient for a proximal Y anastomosis. In 3 cases, an arterial graft was reimplanted distally on the same coronary vessel and in 2 cases onto different coronary vessels. One patient had a combination of these techniques. Five patients required venous conduit.

There were no perioperative deaths. Over 75% of patients showed an improved Canadian Cardiovascular Society class and 90% of patients had a negative postoperative exercise stress test. There were no mid-term angiographic results for follow-up of graft patency.

Pasic et al. [4] reported on 12 patients who underwent repeat harvesting of the LITA during redo CABG. Reused LITA had normal intraluminal diameters on preoperative angiography. Seven patients had stenosis at the distal anastomosis (5 of which were LITA to LAD); and 5 patients had progression of atherosclerotic disease. Time from original operation was from 6 months to 11 years. Postoperative angiography was performed in 10 patients, which showed excellent flow in all patent LITA grafts (2 patients refused as they had no symptoms).

Agrifoglio et al. [5] reported results from a prospective cohort of 9 patients who underwent redo CABG. Indications for redo CABG included: progression of native coronary artery disease (4 patients) and early stenosis at the anastomotic site (5 patients). The mean interval between operations was 27.7 ± 42.3 months (range 1–132 months). The LITA was anastomosed to the LAD in 8 patients. One young patient required the interposition of a short segment of saphenous vein between the left pedicle ITA and target LAD. The recycled right ITA was used to anastomose the right coronary artery distal to the previous anastomosis. Postoperative coronary angiography performed in 8 survivors during June–December 2006. Fifteen-year freedom from restenosis of recycled ITA graft was 75.0 ± 21.7%. Survival at 15 years was 83.3 ± 15.2% (1 patient died from non-cardiac causes). One patient required angioplasty of a stenosed graft between an elongated LITA and an interposed saphenous vein graft. The study concluded that recycled ITA grafts can be used with excellent clinical results in carefully selected redo CABG populations.

Noyez and Lacquet [6] reported the use of a recycled LITA in redo CABG. In their prospective cohort study in 1993, 206 patients underwent coronary revascularization, 5 of which had a recycled left ITA (2 of the 5 patients had a lack of suitable bypass conduits). There was no evidence of a perioperative infarction. Follow-up ranged from 5 months to 4 years and all patients had an improved NYHA class of I. Postoperative re-evaluation by the exercise stress test was 80% negative. They concluded that the recycled LITA was a viable conduit option in redo CABG, but no postoperative angiograms were performed to assess graft patency.

Antona et al. [7] reported on 4 patients who underwent redo CABG using ITAs that were patent but with severe stenosis at the distal anastomosis. Postoperative angiography at 15 days, 7 months and 35 months showed patency in all grafts. This prospective study concluded that although a challenging operation, with appropriate preoperative imaging and planning recycling, the ITA during redo CABG is an acceptable conduit with good long-term outcomes.

There have also been 4 case reports on reusing the ITA/ITA in redo CABG with no damage to the reused LITA, no perioperative mortality and satisfactory follow-up at up to 29 months [8–11]. Vivirito et al. [10] uniquely describe recycling a free LITA–LAD graft.

CLINICAL BOTTOM LINE

When it is possible to harvest a previously used ITA, studies have shown it to be a safe and viable conduit in redo CABG with good long-term outcomes.

Conflict of interest: none declared.