A 60 year-old gentleman with longstanding stage D non-ischemic cardiomyopathy and left ventricular ejection fraction of 10% underwent Heartmate II left ventricular assist device (LVAD) implantation (Abbott) after presenting with acutely decompensated heart failure. He was heterozygous for Factor V Leiden thrombophilia, with prior deep vein thrombosis and pulmonary embolism. Five days following LVAD implantation, he developed incessant ventricular fibrillation (VF) with evidence of ST elevations in anterior precordial leads. Flows on LVAD were reduced during the VF, but he remained relatively hemodynamically stable. Per standard LVAD protocol, he was on antiplatelet therapy with 81mg of aspirin daily, and IV unfractionated heparin while awaiting to achieve a therapeutic INR. INR at the time of STEMI was 1.17, but aPTT was therapeutic at 57.9 seconds on weight-based IV unfractionated heparin. The catheterization lab was emergently activated.
Dr. Sriram Nathan (Advanced Heart Failure Cardiologist): Advanced heart failure in the United States is on the rise. It affects an estimated 5.7 million Americans and more than 23 million people worldwide. As this disease progresses, functional status declines, which results in multiple admissions for acute decompensations, originally responsive to medical therapy, but ultimately becoming advanced and refractory to all medical therapies. This often indicates a reduction in cardiac index to less than 2.2L/m/m2. Once this occurs, overall prognosis is very guarded, with a mortality rate of greater than 90% at 1 year. Advanced therapy including mechanical circulatory support or heart transplantation offers a significant mortality benefit with close to 90% survival at one year, and significantly improves quality of life. In this case, the patient is known to have a hypercoagulable state and thus was maintained on therapeutic anticoagulation in the immediate post-operative period. Cardioembolic events with thrombus embolizing to the coronary arteries (usually to the right coronary artery) rarely occur following LVAD implantation and should be treated percutaneously in the same manner as acute coronary syndrome (ACS) patients with relative contraindication to the use of lytic therapy in the immediate post-operative period.
Diagnostic angiography was performed using 6 French (Fr) Judkins left (JL) 4 and Judkins right (JR) 4 catheters. The aortic valve was noted to be closed throughout the cardiac cycle. The root appeared to be partially thrombosed and thrombus was extending into the left main (LM) coronary artery (Figure 1). Heparin was discontinued and bivalirudin (0.75mg/kg IV followed by 1.75mg/kg/hour infusion) was given upon arrival to the catheterization lab. Activated clotting time (ACT) was >250. He was still in continuous VF, but due to the presence of an LVAD, he was awake. A 6 Fr XB left anterior descending (LAD) coronary artery guiding catheter (Cordis, A Cardinal Health company) was used to engage the LM. A Runthrough wire (Terumo) was used to wire the LAD. Serial balloon dilation and aspiration thrombectomy with a Pronto catheter (Teleflex) was unsuccessful in restoring TIMI-3 flow in the LAD. Intracoronary (IC) abciximab (0.25mcg/kg) was given, followed by IC tPA and AngioJet mechanical thrombectomy (Boston Scientific). Persistent high clot burden remained (Figure 2).
Dr. Marwan Jumean (Interventional and Advanced Heart Failure Cardiologist): Acute coronary syndromes (ACS) in LVAD patients are rare, with only case reports published in the literature with various incidences. This is usually cardioembolic until proven otherwise, often from clot formation on the non-coronary cusp of a closed aortic valve. The initial strategy of restoring TIMI-3 flow failed given the high clot burden. Unconventional therapeutic approaches such as the use of AngioJet mechanical thrombectomy, IC abciximab and low dose IC thrombolytics also failed. At that point, accepting that salvaging the heart was unlikely to happen, a decision was made to focus on 1) preserving life and 2) preventing a cardioembolic stroke. Thus, LVAD speed was increased to maintain continuous closure of the aortic valve, and in addition to bivalirudin therapy, antiplatelet therapy beyond aspirin included eptifibatide for 18 hours at 1mcg/kg/min followed by intravenous cangrelor at 4mcg/kg/min in the intensive care unit.
The patient remained in and out of VF in the ensuing hours, with progressive cardiogenic shock due to right ventricular failure from left main thrombosis. This included signs of hypoperfusion with hypotension and low dose pressor usage, rising serum lactate levels, and progressive decline in urine output. Echocardiogram revealed a significant increase in left ventricular wall thickness indicative of a total myocardial infarction (Figures 3-4).
Dr. Marwan Jumean: While this patient had an LVAD, the use of RVAD support only (Impella RP or TandemHeart RVAD) will not support the progressive severe restrictive physiology that has developed in the left ventricle due to severe wall edema that impacted LVAD filling and flow. As such, venoarterial extracorporeal membrane oxygenation (VA-ECMO) was the only viable percutaneous mechanical support option in this scenario. This was done via percutaneous femoral approach with a 17 Fr single stage arterial cannula and a 21 Fr multistage venous cannula placed in the right femoral artery and vein, respectively. A 6 Fr Arrow sheath (Teleflex) was placed in the right superficial femoral artery for antegrade limb perfusion per our standard limb protection protocol. The patient stabilized on VA-ECMO and underwent 70 cc total artificial heart (TAH) placement after 48 hours on VA-ECMO support.
Dr. Mehmet H. Akay (Cardiothoracic and Transplant Surgeon): TAH is a form of surgical mechanical circulatory support in which the patient’s native ventricles and valves are explanted and replaced by a pneumatically powered artificial heart. The SynCardia TAH is currently the only approved TAH by the FDA for commercial use. There has been over 1400 TAH implants worldwide, with over 70% survival rate to heart transplantation or 1 year. In this case, extensive root thrombosis was removed from the aortic root (Figure 5). Major complications of TAH implantation include strokes, infection, bleeding, thrombosis, renal failure, and chronic anemia. The patient’s history of Factor V Leiden was a major concern proceeding with TAH, but as this was felt to be his only option to survive, decision as a team was made to proceed with TAH implantation and meticulous peri-operative anticoagulation and antiplatelet therapy.
The patient was maintained on triple antiplatelet therapy of aspirin, dipyridamole, and pentoxifylline, along with warfarin with a target INR of 2.5-3.5. He recovered following TAH implantation and despite extensive aortic root thrombosis, he was discharged to a cardiac rehabilitation facility without any neurologic deficits.
This case demonstrates the value of a true multidisciplinary approach to successful cardiogenic management. The collaborative care between the heart failure cardiologist, interventional cardiologist, and cardiothoracic surgeon was crucial in this case. The patient developed a catastrophic complication of aortic root thrombosis that could not have been managed medically only, and his ACS could not have been managed with percutaneous coronary revascularization either, despite attempts made in the catheterization lab. The critical care team managing the patient in the cardiogenic shock intensive care unit identified signs of shock early on and deployed appropriate support. The choice of percutaneous mechanical circulatory support device and timing of deployment was critical to a successful outcome. Lastly, such multidisciplinary care allows for a better understanding of viable exit strategies in cardiogenic shock, which in this case, was a TAH.
About the Physicians
Dr. Marwan F. Jumean is board certified in internal medicine, cardiovascular diseases, interventional cardiology, advanced heart failure and transplant cardiology, and nuclear cardiology. Dr. Jumean is the director of the Interventional Heart Failure fellowship program. He is the director of the Houston Shock Symposium, an annual event that aims at advancing the field of cardiogenic shock diagnosis and management in a true multidisciplinary team approach.
Dr. Sriram Nathan is an Associate Professor of Medicine at the University of Texas Health Science Center at Houston and Director Cardiogenic Shock, Center for Advanced Heart Failure, Memorial Hermann Hospital, Houston, Texas. As an advanced heart failure cardiologist, his specific area of expertise is treating the sickest acute and chronic heart failure patients that require temporary or long-term mechanical circulatory support or heart transplantation.
Dr. Mehmet H. Akay is a board-certified physician at McGovern Medical School at The University of Texas Health Science Center at Houston. Dr. Akay sees adults with advanced heart failure within the U.S. and internationally.