Intraoperative graft patency validation: Friend or foe?

Intraoperative Invasive Coronary Angiography after Coronary Artery Bypass Grafting

OBJECTIVE

 The aim of this study was to prospectively evaluate the feasibility and safety of intraoperative invasive coronary angiography (ICA) following coronary artery bypass grafting using a mobile angiography C-arm.

METHODS

 Between August 2020 and December 2021, 18 patients were enrolled for intraoperative ICA following coronary artery bypass grafting. After skin closure, ICA was performed including angiography of all established bypass grafts via a mobile angiography system by an interventional cardiologist. Data on graft patency, stenosis, and kinking were assessed. Grafts were rated on an ordinal scale ranging from very poor (1) to excellent (5). Furthermore, the impact of ICA compared with flow measurement was assessed using the ordinal Likert scale ranging from (I) worse to (V) much better.

RESULTS

 The ICA was considered better (V) compared with transient flow measurement in 38 (93%) and comparable (III) in 3 (7%) distal anastomoses. ICA impacted clinical or surgical decision-making in three patients (17%). In one patient, dual antiplatelet therapy for 6 months was initiated and rethoracotomy was needed in two (11%) patients with bypass graft revision and additional bypass grafting for graft occlusion. There were no cerebral and distal embolic events or access vessel complications observed and no postoperative acute kidney injury occurred.

CONCLUSION

 Intraoperative angiography after coronary bypass grafting is safe. Using a mobile angiographic device, graft patency, and function assessment was superior to transit time flow measurement leading to further consequences in a relevant number of patients. Therefore, it has the potential to reduce postoperative myocardial injury and improve survival.

Transient time flow measurement in arterial grafts

Coronary artery bypass grafting (CABG) is one of the foundations of treatment for coronary artery disease. While it has improved substantially since its inception more than 50 years ago, including a rising use of multiple arterial grafting, intraoperative quality assessment is yet to be disseminated as an integral part of the procedure. Herein we review the fundamentals of intraoperative quality assessment in CABG using transient time flow measurement (TTFM) with a focus on its use in arterial grafting.

Management of Coronary Artery Bypass Grafting Using an Arteriovenous Fistula: An Intraoperative Change in the Preoperative Plan

Regarding coronary artery bypass grafting (CABG) in patients on hemodialysis, in situ internal thoracic artery (ITA) grafting of the left anterior descending artery (LAD) improves survival and freedom from cardiac events. Although a problem with the ITA can possibly occur, using the ITA ipsilateral to an arteriovenous fistula (AVF) in the upper extremity of patients on hemodialysis can cause coronary subclavian steal syndrome (CSSS). CSSS is a condition of myocardial ischemia caused by the diversion of blood flow from the ITA following coronary artery bypass surgery. CSSS has been reported to occur in cases of subclavian artery stenosis, AVF, and low cardiac function. A 78-year-old man with end-stage renal disease experienced angina pectoris during hemodialysis. The patient was scheduled for CABG, including anastomosis of the left internal thoracic artery (LITA) and LAD. After completion of all anastomoses, the LAD graft demonstrated retrograde blood flow, suggestive of ITA anomalies or CSSS. The LITA graft was transected at the proximal part and anastomosed to the saphenous vein graft with sufficient flow to the high lateral branch eventually.

Risks and Outcomes of Reoperative Cardiac Surgery in Patients with Patent Bilateral Internal Thoracic Artery Grafts

BACKGROUND

Reoperative cardiac surgery in patients with patent bilateral internal thoracic arteries (ITA) grafts is technically challenging.

METHODS

From 2008-2017, of 7,640 patients undergoing reoperative cardiac surgery, 116 (1.5%) had patent bilateral ITA grafts, including 28 with a right ITA crossing the midline. Mean age was 70±9.6 years, and 111 patients (96%) were male. Reoperations included isolated coronary artery bypass grafting (CABG; n=11), isolated valve (n=55), valve+CABG (n=26), and other procedures (n=24). Clinical details, intraoperative management, and perioperative outcomes were analyzed.

RESULTS

Aortic cannulation was central in 64 patients (56%) and via femoral or axillary artery in 50 (44%). Four patients (3.4%) had planned transection and reattachment of ITAs crossing the midline, and 4 (3.4%) had ITA injuries, all right ITAs, 3 crossing the midline; 3 were repaired with an interposition vein graft, and 1 was managed by translocating the right ITA as a Y-graft off another graft. Patent ITAs were managed by atraumatic occlusion during aortic clamping in 90 patients (78%) and by systemic cooling without ITA occlusion in 19. There were 6 operative deaths, all due to low cardiac output syndrome (5.2%), 4 strokes (3.4%), and 5 cases of new postoperative dialysis (4.3%).

CONCLUSIONS

Risk of injury to bilateral ITA grafts during reoperation is high, and right ITAs crossing the midline present a particular risk of injury and should inform planning for primary CABG. Risk of low cardiac output syndrome underscores the challenge of ensuring adequate myocardial protection.