Use of Temporary Percutaneous Left Ventricular Support in a Patient with Profound Cardiogenic Shock (Full title below)

Use of Temporary Percutaneous Left Ventricular Support in a Patient with Profound Cardiogenic Shock from a Non-Ischemic Cardiomyopathy

Summary We report a case involving a 61-year-old man who presented with profound cardiogenic shock secondary to a non-ischemic cardiomyopathy. The use of temporary percutaneous left ventricular support with the Abiomed Impella 2.5 circulatory support device restored acceptable hemodynamics, improved cardiac output, reduced left ventricular wall tension, and improved myocardial perfusion, allowing left ventricular recovery over the ensuing 72-96 hours. Patient Presentation A 61-year-old man, without known cardiac disease other than palpitations, was admitted with a one-week history of increasing dyspnea, atrial fibrillation of unknown duration with a rapid ventricular response (heart rate = 150), hypotension (blood pressure = 95/50 mmHg), pulmonary edema on chest x-ray, and evidence of systemic hypoperfusion, including a metabolic acidosis (pH = 7.1), anuria (serum creatinine = 2.7 µmol/L), and elevated liver function tests (AST 5088 U/L, ALT 3884 U/L) consistent with “shock liver.” Direct cardioversion of atrial fibrillation was performed due to hemodynamic deterioration, but was unsuccessful. A transthoracic echocardiogram showed dilated left ventricular (LV) cavity with end diastolic dimension (LVEDD) of 6.9 cm, end systolic dimension (LVESD) of 6.4 cm, and a left ventricular ejection fraction (LVEF) of 10% with global hypokinesis. The patient required mechanical ventilation, inotropic support and continuous veno-venous hemofiltration for volume removal. Emergency cardiac catheterization showed elevated left heart filling pressures (mean pulmonary artery pressure = 34 mm Hg, mean pulmonary capillary wedge pressure = 28 mm Hg). Coronary arteriography showed minor lumen irregularities in the left coronary artery, and diffuse 95% disease in the right coronary artery supplying a small posterior descending and posterolateral cascade. It was felt that the extent of acute left ventricular failure was out of proportion to the coronary artery disease, and was attributable to an acute myocarditis (e.g., giant cell myocarditis), sustained tachycardia syndrome, or acute on chronic left ventricular dysfunction. Device Description Due to hemodynamic collapse in the setting of severely compromised left ventricular dysfunction, an Abiomed Impella 2.5 (Abiomed, Danvers, MA) percutaneous left ventricular support device was placed (Figure 1). Through a 13 Fr femoral sheath, a JR-4 coronary guiding catheter was used to advance a 0.018-inch guide wire that was positioned in the left ventricle. The guiding catheter was removed and the Impella 2.5 support system was advanced over the wire and positioned in the left ventricle. The wire was then removed and the motor was adjusted to provide maximum cardiac output (Figure 2). Clinical Course The patient was transferred to the coronary care unit (CCU) with the Impella 2.5 device in place at P7 (~ 2.2 L/min support) for hemodynamic stabilization of the non-ischemic cardiomyopathy. There was immediate improvement of left heart filling pressures (mean PA pressure = 22 mmHg, PA diastolic pressure = 15 mm Hg, mean pulmonary capillary wedge pressure = 12 mm Hg). High-dose corticosteroids were given empirically for possible giant cell myocarditis. The patient continued to develop frequent runs of paroxysmal atrial flutter and fibrillation (Figure 3), but with Impella 2.5 hemodynamic support in place, beta blockers were tolerated for rate control and a successful cavo-triscuspid isthmus atrial flutter ablation was performed. The patient’s systolic blood pressure stabilized (> 110 mm Hg) and the liver function tests returned toward normal, although the patient remained oliguric due to acute tubular necrosis and required hemodialysis. A repeat echocardiogram after three days of Impella support demonstrated an LVEF of 35% and significantly reduced left ventricular systolic (LVESD 4.8 cm) and diastolic dimensions (LVEDD 6.2 cm). The Impella 2.5 device was weaned on the fourth day without incident. A repeat echocardiogram after removal of the Impella 2.5 device demonstrated persistently improved LVEF (35%) and LV cavity dimensions (LVESD 4.8 cm, LVEDD 6.3 cm). The patient was extubated on day 10 and discharged on hospital day 14. At one month after discharge, the patient remains on hemodialysis, but is no longer oliguric, and functionally independent at NYHA Class 1. Discussion We describe a case of profound cardiogenic shock resulting from a non-ischemic cardiomyopathy, in which temporary percutaneous left ventricular support using the Abiomed Impella 2.5 resulted in clinical stabilization of the patient and myocardial recovery over the ensuing days. We believe that this innovative use of left ventricular support may have value in patients with sudden hemodynamic deterioration due to cardiac failure, including patients with myocarditis, post-partum cardiomyopathy, and in selected patients with acute on chronic left ventricular systolic dysfunction. Use of the Impella 2.5 circulatory support device may have had several complementary effects in this case. First, blood pressure and cardiac output were improved with the use of the Abiomed device, reducing the need for ionotropic and pressor support during this critical time period. Experimental and clinical studies have shown that hemodynamic improvement is due to an increase in the cardiac output owing to the direct effects of the Impella device, albeit with a reduction in cardiac output due to instrinsic myocardial contractility, in effect, “resting” the myocardium during the time of hemodynamic collapse.1-4 More importantly, percutaneous left ventricular assist devices reduced both the left ventricular end diastolic and end systolic pressures and volumes, reducing left ventricular oxygen demand.2,5 Based on pressure volume simulation (Figure 4), there is a more profound leftward and downward shift with the use of the Impella percutaneous left ventricular assistance than with inotropes or with an intra-aortic balloon pump (Figure 5). Thirdly, maximum ventricular wall tension, T, occurs at end diastole and can be characterized using the Law of Laplace as: where EDP is the end diastolic pressure, EDV is the end diastolic volume and w is the ventricular wall thickness. By reducing the maximum wall tension and microvascular resistance, myocardial blood flow is improved.6,7 Finally, the Impella provided temporary hemodynamic stabilization so that an ablation procedure for the refractory atrial arrhythmia could be performed. We conclude from this case that the Impella 2.5 circulatory support device may be beneficial in patients with acute cardiogenic shock caused by non-ischemic cardiomyopathy. The improvement in left ventricular systolic function in this case may have occurred by unloading the left ventricle, improving cardiac output and myocardial blood flow, and halting the hemodynamic spiral associated with cardiogenic shock. The authors can be contacted via Dr. David Leeman at dleeman@bidmc.harvard.edu

1. Burzotta F, Paloscia L, Trani C, et al. Feasibility and long-term safety of elective Impella-assisted high-risk percutaneous coronary intervention: a pilot two-centre study. J Cardiovasc Med (Hagerstown) Oct 2008;9(10):1004-1010.

2. Valgimigli M, Steendijk P, Sianos G, et al. Left ventricular unloading and concomitant total cardiac output increase by the use of percutaneous Impella Recover LP 2.5 assist device during high-risk coronary intervention. Catheter Cardiovasc Interv Jun 2005;65(2):263-267.

3. Dixon SR, Henriques JP, Mauri L, et al. A prospective feasibility trial investigating the use of the Impella 2.5 system in patients undergoing high-risk percutaneous coronary intervention (The PROTECT I Trial): initial U.S. experience. JACC Cardiovasc Interv Feb 2009;2(2):91-96.

4. Seyfarth M, Sibbing D, Bauer I, et al. A randomized clinical trial to evaluate the safety and efficacy of a percutaneous left ventricular assist device versus intra-aortic balloon pumping for treatment of cardiogenic shock caused by myocardial infarction. J Am Coll Cardiol Nov 4 2008;52(19):1584-1588.

5. Reesink KD, Dekker AL, Van Ommen V, et al. Miniature intracardiac assist device provides more effective cardiac unloading and circulatory support during severe left heart failure than intraaortic balloon pumping. Chest Sep 2004;126(3):896-902.

6. Remmelink M, Sjauw KD, Henriques JP, et al. Effects of left ventricular unloading by Impella recover LP2.5 on coronary hemodynamics. Catheter Cardiovasc Interv Oct 1 2007;70(4):532-537.

7. Sauren LD, Accord RE, Hamzeh K, et al. Combined Impella and intra-aortic balloon pump support to improve both ventricular unloading and coronary blood flow for myocardial recovery: an experimental study. Artif Organs Nov 2007;31(11):839-842.