Innovations: Technology & Techniques in Cardiothoracic & Vascular Surgery:
Castillo-Sang, Mario A. MD*; Prasad, Sunil M. MD†; Singh, Jasvindar MD‡; Ewald, Gregory A. MD‡; Silvestry, Scott C. MD†
From the *Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, Charleston, SC USA; and †Division of Cardiothoracic Surgery, Department of Surgery, and ‡Division of Cardiology, Department of Medicine, Washington University School of Medicine, St Louis, MO USA.
Accepted for publication June 24, 2013.
Disclosure: The authors declare no conflicts of interest.
Address correspondence and reprint requests to Scott C. Silvestry, MD, Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, CB8234, 660 S. Euclid Ave, St Louis, MO 63110 USA. E-mail: firstname.lastname@example.org.
Abstract: We describe the use of an Impella 5.0 for mechanical support in acute cardiogenic shock after an acute myocardial infarction. A 61-year-old man with a history of severe coronary artery disease who underwent coronary artery bypass grafting with ischemic cardiomyopathy presented with cardiogenic shock after an ST-elevation myocardial infarction. An Impella Recover LP 5.0 (Abiomed, Danvers, MA USA) was inserted via a right axillary side graft, using transesophageal echocardiographic and fluoroscopic guidance. The patient remained in the intensive care unit, where he required a tracheostomy to be weaned off the ventilator. He required renal replacement therapy with subsequent complete recovery. His Impella support was weaned, and on postoperative day 35, the device was removed. The patient developed axillary thrombosis the morning after removal, requiring thrombectomy. Discharge echocardiogram showed mild left ventricular enlargement with global hypokinesis and left ventricular ejection fraction of 25%. The Impella 5.0 device can safely and effectively be used in the long-term support of cardiogenic shock.
The Impella 5.0 (Abiomed, Inc, Danvers, MA USA) has been used to support patients in acute cardiogenic shock refractory to inotropic support. The device is a 21F microaxial pump capable of producing flows up to 5 L/min while positioned across the aortic valve, with the inflow sitting inside the left ventricle and the outflow at the sinotubular junction. The device is approved for 6 hours of use in the treatment of cardiogenic shock. A previous report has described the use of the device via right axillary artery cannulation using a side graft.1 Impella 5.0 support as long as 18 days has been described in the literature. We report the case of the longest indwelling Impella for cardiogenic shock support inserted via a right axillary artery side graft.
We present the case of a 61-year-old man with a history of ischemic cardiomyopathy and coronary artery bypass grafting who presented to an outside hospital with unstable angina, troponins of 25 ng/mL, and ST-segment elevation in the anterolateral leads. He underwent left-sided heart catheterization and was found to have 100% occlusion of all his grafts including the left internal mammary artery. Admission transthoracic echocardiogram showed normal right ventricular function and severely depressed left ventricular function with an ejection fraction of 15%. Because of his cardiogenic shock, an intra-aortic balloon pump was placed using a percutaneous right femoral artery approach.
The patient was transferred to our institution hypotensive on pressor and inotropic drug support, on intra-aortic balloon pump, and in pulmonary edema. His troponin levels rose to 213 ng/mL, and because of progressive refractory cardiogenic shock, we placed an Impella Recover LP 5.0 (Abiomed, Danvers, MA USA) through the right axillary artery via a side graft. The axillary approach was chosen to allow the patient ambulation and rehabilitation once off ventilator support. A subclavicular cutdown was performed to access the axillary artery. Proximal and distal control were obtained. The patient was heparinized to an activated clotting time (ACT) of greater than 200 seconds, and an 8-mm Hemashield Platinum graft (Boston Scientific, Natick, MA USA) was anastomosed end to side to the axillary artery using 5-0 polypropylene suture. The graft was tunneled under the skin and subcutaneous tissue, exiting the chest lateral to the right nipple. The Impella sheath was introduce at the end of the graft and secured with silk ties. The Impella was then introduced through the sheath and advanced over a guide wire and positioned across the aortic valve using echocardiographic and fluoroscopic guidance. Figure 1 shows the postinsertion chest radiograph with the Impella positioned across the aortic valve. In the same setting, percutaneous coronary interventions were performed on the left anterior descending, left main, and circumflex coronary arteries, deploying bare metal stents.
The patient remained in the intensive care unit and required a tracheostomy to wean from ventilatory support. The patient was maintained on a systemic weight-based heparin infusion to maintain an ACT of 180 seconds (heparin infusion dose ranging from 7 to 16 U/kg per hour). The purge fluid was maintained per manufacturer recommendations for the Impella 5.0 (20% dextrose in water with 50 IU/mL of heparin). The patient required 2 U of packed red blood cells 1 day after his operation and 2 U more after removal of the intra-aortic balloon pump because of losses at the removal site. On postoperative day 12, the patient developed upper gastrointestinal bleeding, requiring 3 U of packed red blood cells for a period of 4 days. Upper endoscopy demonstrated congestive hemorrhagic and erosive gastropathy with diffuse superficial ulceration. The gastrointestinal bleeding was managed by increasing the dose of proton-pump inhibitor and decreasing the anticoagulation for a lower ACT goal of 150 to 160 seconds. Despite lower ACT goals, we did not encounter hemolysis, based on normal haptoglobin and lactate dehydrogenase levels. The patient required renal replacement therapy initially but subsequently recovered renal function while on the Impella support. On inotropic support (intravenous Dobutamine at 5 μg/kg per minute), his cardiac function improved on successively lower levels of Impella support. On the 35th day of support, the device was removed. After exposure of the side, the device was pulled from the patient, and the side graft was then ligated close to the artery. The patient developed axillary artery thrombosis the morning after Impella removal, treated successfully with axillary thrombectomy.
The patient recovered and was transferred to the ward. Postremoval echocardiogram showed mild left ventricular enlargement with global hypokinesis, apical akinesis, and overall severely decreased left ventricular systolic function with a left ventricular ejection fraction of 20% to 25%. The patient was discharged 51 days after admission.
The Impella 5.0 has been shown to be a safe and effective management of cardiogenic shock after cardiotomy1,2 and primarily after acute myocardial infarction complicated by shock.1,3,4 The use of the Impella 5.0 device is approved for up to 6 hours, with published reports of significantly longer periods of support up to 18 days.1 This case illustrates successfully bridging a patient through acute cardiogenic shock in the setting of S-T elevation myocardial infarction, allowing percutaneous revascularization and end-organ recovery. In our review of the literature, 35 days is the longest support duration using an Impella 5.0. Explantation was complicated by a thromboembolic event likely originating from a preexisting clot at the site of the chimney graft. In retrospect, decannulation should be done, obtaining both proximal and distal control of the vessel and clamping the distal axillary artery to prevent downstream embolization; then, after removing the Impella 5.0, the artery and the side graft should be inspected for clot before removing the proximal and the distal control.
In conclusion, the Impella 5.0 device may be effectively used for prolonged support in select cardiogenic shock patients. Careful attention to adequate anticoagulation and monitoring for bleeding complications are important during prolonged supports.
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