In The News
Effect of Continuous Left Ventricular Assist Device Blood Flow in a Free Flap
23 Nov 16
Perry Mansfield, MD, FRCS(C)1, Michael Halls, BS, MD, FACS2., Walter Dembitsky, M.D3, Michael O'Leary, MD, FACS 1, Natalya Sarkisova, BS 1, Hannah Goldman1, Lauren-Taylor Mansfield1
In this case report, a patient with a history of squamous cell carcinoma of the right ear and temporal bone underwent a radical resection for recurrent squamous cell carcinoma. With free tissue transfers being commonly used in the setting of head and neck malignancies, a radial forearm free tissue flap for reconstruction of the defect was used. The patient's peripheral perfusion was governed by a left ventricular assist device (CLVAD), and implanted pacemaker. This continuous flow device altered typical peripheral perfusion in the post transplanted free flap. This case report discusses the specific findings and outcome of a free tissue transfer in a continuous flow state. making the outcome of the surgery difficult to predict when taking into regards the patients' mechanical devices. This patient case serves to show the impact of continuous flow in a free tissue transfer.
A 93 year old male patient with congestive heart failure, a Heartmate II left ventricular assist device and implanted pacemaker underwent a right lateral skull base resection status post radiation failure for a recurrent T4N0M0 squamous cell carcinoma of the right ear. A left radial forearm tissue transfer was used for reconstruction of the right auricular defect. During surgery, the patient did not maintain a pulse but rather a peripheral continuous flow state. Repeated bouts of electrocautery induced systole were encountered necessitating external pacing. Post-transplant Doppler analysis of continuous flow demonstrated adequate tissue perfusion and resulted in adequate flap viability despite a lack of pulsatile flow.
Management and Outcome:
Post transplant flap inspection demonstrated a dusky appearance in flap totality. The continuous flow perfusion Doppler was adequate for both arterial and venous phases. CLVAD mechanical dynamics causes break down of "Something" causing increased hematoma formation. Post operative hematoma management and and adequate drainage was necessary to maintain the hematoma.
Pulsatiltiy- magnitude of the arterial pressure pulse
The heart mate II CVAD is well known for its reliability, durability and smaller size.
Its been linked complications of GI bleeding, arteriovenous malformation, hemolysis, pump thrombosis and aortic insufficiency.
Diminished pulsatility-> reduces blood flow to the gut → contributing factor in development of arteriovenous malformations
Increased pressure gradients on aortic valve, decreased compliance in smaller arterial vessels
Pulsatile vs continuous
Maximal flow rate with PF had greater effect on wall shear stress than CF (Frictional force generated by blood flow)
Diminished pulsatile arterial pressure and flow pulsatility → decreased bradykinin dependent vascular relaxation, reduced nitric oxide production, increased oxidative stress → ischemic cascade → Oxygen reperfusion injury following hypoxia, decrease nitric oxide leads to vasoconstriction
Microcirculatory flow patterns are different between CF and PF
PF provided better microcirculation in both kidney and liver
Cfvad- increase in vascular resistance r=deltaP/Q, , increase in resistance causes decrease in flow