Avoiding ischemia in latissimus dorsi muscle grafts: electrical prestimulation versus vascular delay.
BACKGROUND
Surgical mobilization of the latissimus dorsi muscle produces regional ischemic damage that may compromise its function in clinical applications such as cardiomyoplasty. We compared the effectiveness of two procedures designed to maintain blood flow throughout the mobilized muscle.


METHODS
Adult pigs were assigned to two experimental groups: an electrically prestimulated group (n = 10) and a vascular delay group (n = 10). In the prestimulated group the left latissimus dorsi muscle was activated in situ at 2 Hz for 24 h/d. In the vascular delay group, the intercostal perforating arteries to the left latissimus dorsi muscle were divided. Two weeks later, hyperemic blood flow was measured by means of fluorescent microspheres immediately before and after mobilizing the latissimus dorsi muscle and again after recovery for a further 2 days.


RESULTS
In the prestimulated group, blood flow was not significantly depressed in any region of the muscle immediately after mobilization, and blood flow increased significantly in proximal (p = 0.01), middle (p = 0.02), and distal (p = 0.007) regions following recovery. In muscles subjected to vascular delay the proximal and middle regions showed no significant changes in blood flow after mobilization or recovery, but flow in the distal region was 50% lower after mobilization (p = 0.003), and it remained significantly depressed even after recovery (p = 0.008).


CONCLUSIONS
Prestimulation was significantly more effective than vascular delay in preserving distal blood flow. Because it is also less invasive and initiates metabolic transformation before mobilization, this technique should allow cardiac assistance to be introduced at an earlier postoperative stage without compromising the viability of the grafted muscle.
Woo
Edwin B C
EB
Department of Cardiothoracic Surgery, Wythenshawe Hospital, Manchester, United Kingdom.
Jarvis
Jonathan C
JC
Hooper
Timothy L
TL
Salmons
Stanley
S
D000818:Animals; D004558:Electric Stimulation; D007511:Ischemia / Q000517:prevention & control*; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000637:transplantation*; D011183:Postoperative Complications / Q000517:prevention & control*; D012039:Regional Blood Flow; D019739:Skeletal Muscle Ventricle; D013552:Swine; D013997:Time Factors; D014656:Vascular Surgical Procedures