A 53-year-old woman is recovering in the ICU on postoperative day 2 after undergoing LVAD implantation. Over the course of several hours she is noted to become progressively hypotensive with her mean arterial pressure dropping from 75 to 53 mm Hg as measured by a radial arterial line. Her LVAD monitor shows multiple power spikes in the last 2 hours. Her nurse additionally notes that the patient’s urine has become much darker in color over the last several hours.
Which of the following is the next best step in management?
Correct Answer: C
In this patient with a recently implanted LVAD, hypotension in conjunction with power spikes on the LVAD and clinical signs of hemolysis is strongly suggestive of pump thrombosis, which can be seen as both an early and late complication of VAD therapy. Pump thrombosis that results in pump obstruction is associated with high mortality and requires prompt diagnosis and management. The diagnosis is here suggested by changes in pump performance, most commonly surges in power, along with clinical signs of hemolysis (hemoglobinuria). In addition to laboratory markers of hemolysis, echocardiographic ramp studies during which left ventricular parameters are measured at varying pump speeds have been shown to be both sensitive and specific for pump thrombosis. Early pump thrombosis generally requires urgent surgical pump exchange or heart transplantation, whereas late pump thrombosis can sometimes be managed with intensified anticoagulation. Echocardiogram without a ramp study is not helpful in diagnosing pump thrombosis. CT angiography is reserved for selected patients when the diagnosis is challenging after echocardiographic ramp study.
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A 49-year-old male is admitted to the ICU following a witnessed cardiac arrest and successful resuscitation. His postarrest ECG showed anteroseptal ST elevations, and he underwent emergent coronary angiography and revascularization of a thrombotically occluded left anterior descending artery. He was placed on VAECMO for ongoing cardiogenic shock during the procedure. Several hours after admission to the ICU, the pulsatility of his arterial waveform begins to decrease, and increasing amounts of frothy secretions are being suctioned from his endotracheal tube. An echocardiogram shows a markedly dilated left ventricle with an ejection fraction of 10%.
Which of the following would NOT be an appropriate intervention in the management of this patient?
VA-ECMO is an effective strategy to support patients with refractory cardiogenic shock after an acute myocardial infarction; however, ECMO directly increases afterload on the left ventricle, which can worsen left ventricular function. Frequent monitoring of LV size and function with echocardiography and close attention to the pulsatility of the arterial waveform are both critical to identify an overloaded left ventricle. Strategies to improve LV unloading include administration of inotropes (dobutamine, milrinone) to improve inherent native LV ejection, IABP counterpulsation, or a left ventricular “vent” by either percutaneous (percutaneous LVAD) or surgical methods (left ventricular drainage catheter placed via left superior pulmonary vein).
A 52-year-old female is recovering in the ICU after undergoing an uncomplicated orthotopic heart transplant 12 hours earlier. For the last 5 hours her urine output has been decreasing, and she has been requiring increasing doses of inotropes to maintain a median arterial blood pressure of 65 mm Hg or greater. Though the intraoperative TEE showed hyperdynamic function in the transplanted heart, now a transthoracic echocardiogram shows LV systolic dysfunction with an ejection fraction of 30%, with normal right ventricular size and function.
Which of the following is the most likely diagnosis?
Correct Answer: B
Primary graft dysfunction is left ventricular, right ventricular, or biventricular dysfunction that occurs within 24 hours of cardiac transplantation that is not due to an identifiable cause such as hyperacute rejection, pulmonary hypertension, or surgical complications. The cause of primary graft dysfunction is poorly understood, but donor, recipient, and surgical procedural factors all appear to play a role. Treatment involves aggressive pharmacologic and mechanical circulatory support, as well as re-transplantation in select patients. Coronary allograft vasculopathy, infectious myocarditis, and recurrent myocardial disease may be potential causes months to years after transplantation.
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