The Link between Ex Vivo Storage Interval and Subsequent

Failure of Vein GraftsRobert Poston, MD

Chairman, Department of Cardiothoracic SurgerySt Francis Medical Center, Trenton, NJ

Choice of conduit

• Arterial vs. venous: OR 10

Harvesting conduit

• “No touch” vs. conventional: OR 3.1 • Open vs. endoscopic: OR 2

Storage of conduit

Anastomotic technique

• Interrupted vs. continuous: OR 1.4• On-pump vs. off-pump: OR 1.3

Postoperative management

• Aggressive vs. standard statin therapy: OR 1.3• Aspirin vs. no aspirin: OR 2.2

Factors that influencegraft patency post-CABG

?

Mechanism of early graft failure

Endothelial dysfunction

Arterial conduitsMeticulous harvestStatin therapy

Hypercoagulability

Anti-platelet therapyAbnormal flow

Perfect anastomotic technique

THROMBOSIS

Status of bypass graft endothelium

In situ (baseline)

Ex vivo storage (after explant)

After grafting onto

the heart

?Normal endothelium Disrupted endothelium

Recovery of venous endothelium after grafting• Large animal studies• Venous vs. prosthetic grafts

HANDLE WITH CARE

The Vascular Conduit as a Transplant Organ• Veins/arteries are organs:

• differentiated structures comprised of two or more tissues working together to provide a specific function

• Respond to a variety of complex signals including hormones, other molecules and nerve impulses to adjust blood flow

• Correct functioning is dependent upon proper integrated functioning of vessel’s constituent tissues

• Majority of vascular grafts are transplanted autologous vein or artery derived grafts-

• Vascular grafts and heterologous organ transplants are subject to many of the same graft failure mechanisms:• Oxidative damage• Storage lesions• Ischemia Reperfusion Injury

Subanalysis of preservation solutions from the PREVENT IV Trial1• Multicenter, randomized, placebo-controlled trial of edifoligide during

CABG• Enrolled 3014 patients at 107 US sites from 8/1/02 – 10/22/03• Analyzed the impact of preservation solution on graft patency

Saline

Blood

Bufferedsaline

1. Harskamp et al. JAMA Surg. 2014;149(8):798-805

Choice of conduit

• Arterial vs. venous: OR 10

Harvesting conduit

• “No touch” vs. conventional: OR 3.1 • Open vs. endoscopic: OR 2

Storage of conduit

Anastomotic technique

• Interrupted vs. continuous: OR 1.4• On-pump vs. off-pump: OR 1.3

Postoperative management

• Aggressive vs. standard statin therapy: OR 1.3• Aspirin vs. no aspirin: OR 2.2

Factors that influencegraft patency post-CABG

Buffered solution vs. other alternatives: OR 1.7

Ischemic damage is “invisible”

• Bypass graft failure often asymptomatic• Whole organ failure never asymptomatic

Saline/blood standard of care

• Informational cascade

Saline/blood used when training

• Reputational cascade

Selective emphasis of risk

factors

• Easy to see the influence of technical/anatomic factors• Difficult to see the analogy to organ transplant

Factors that influenced choice of vein solution