P020: THE MANAGEMENT OF A PATIENT FOUND TO HAVE HEPARIN-INDUCED THROMBOCYTOPENIA (HIT), A RARE COMPLICATION S/P TAVR PROCEDURE
Reena John, DO1, Jack Guevara, DO1, Ahmed Salim, MS, Michael Decker, MD3, Ana Michelena, MD3, Ryan P Shienbaum, MD3; 1Kendall Regional Medical Center, 2Nova Southeastern University COM, 3Aventura Hospital and Medical Center
83yo Fw/PMH of severe AS, HTN, HLD, CHF, and CKD underwent TAVR. The TAVR procedure was uneventful however, prior to leaving the OR Doppler was used to check for pulses and no pulses were noted on palpation or with use of Doppler.
A stat ultrasound was performed and occlusion of the left popliteal artery with echogenic material was observed, possibly representing an acute thrombus. The left posterior tibial, anterior tibial, dorsalis pedis arteries were not visualized. Occlusion of the right dorsalis pedis, and peroneal arteries were noted as well. Patient was seen by IR and Vascular Surgery and the patient was still had sensation and mobility in both feet. Concern for a possibility of HIT syndrome was raised, and patient was switched from heparin to argatroban, and a heparin-induced platelet antibody study was ordered (which eventually came back positive for HIT & 5HT assay), as well as thrombophilic workup. Further ultrasound study shows occlusion of both popliteal arteries with a slight aneurysm in the left popliteal artery. Patient was also observed to have bilateral severe tibioperoneal occlusive disease with a clot coming down the SFA all the way into the popliteal. Underwent a thomboectomy from the SFA on both sides and continued on argatroban drip post-op.
Discussion: TAVR procedure allows for minimal anesthesia requirements while deploying a replacement valve without removing the old, damaged valve.
Indications for TAVR are the same for surgical AV replacement, however are specifically indicated for patients with symptomatic severe AS and extreme surgical risk (greater than 50 percent probability of death or serious irreversible complication) or with an absolute contraindication to SAVR, with a life expectancy of at least 12 mos.
Contraindications to TAVR include estimated life expectancy less 12 months, untreated coronary artery disease require revascularization, MI within the last 30 days, LVEF less than 20%.
Local anesthesia plus sedation is found to be a reliable alternative general anesthesia. Monitored anesthesia care (MAC) sedation for TAVR has been shown to carry similar clinical outcomes with significantly reduced length of stay.
Other advantages include less hemodynamic manipulations required, shorter ICU stay, no prolonged intubation, early mobilization, and the ability to access neurological status throughout the procedure.
Complications of TAVR include including improper positioning of the valve, coronary compromise, and annular rupture, stroke, myocardial ischemia/injury, aortic regurgitation, and prosthetic valve thrombosis.
Heparin-Induced Thrombocytopenia (HIT) is a life-threatening complication of exposure heparin, which occurs in a small percentage of patients taking heparin.
HIT occurs because of an autoantibody directed against platelet factor-4 when in complex with heparin activateing platelets and cause life-threatening arterial and venous thrombosis with a high rate of mortality.
Patients undergoing TAVR are placed on a heparin drip post-op.
If there is clinical suspicion of HIT, presenting with signs of ischemia and arterial or venous thromboses, immediate intervention is required due to the high rate of mortality.
Interventions include discontinuing heparin, and initiating a non-heparin anticoagulant such as argatroban, fondaparinux, bivalirudin, and much more.
More invasive procedures if thrombosis does occur, involve a thombectomy.