Bail-Out Use of Impella CP as a Bridge to TAVI in a Cardiogenic Shock Patient: The "Pump-Rewiring" Technique

Abstract: Background. The optimal management of cardiogenic shock (CS) occurring in the presence of acute coronary syndromes, severe aortic stenosis, and poor left ventricular function has not been established. Recently, the availability of new assistance devices and techniques has provided novel management opportunities. In particular, when compared with surgical approaches, percutaneous procedures have the advantage of allowing “staged” interventions, in which different steps are planned according to the patient’s evolving clinical conditions. Case Presentation. A woman was admitted with an acute coronary syndrome complicated by CS on a background of severe aortic stenosis, severe left ventricular dysfunction, and severe calcific peripheral artery disease. We successfully treated her with emergency percutaneous coronary intervention (PCI) to left main stem followed by balloon aortic valvuloplasty (BAV). After BAV, acute aortic regurgitation developed with sudden hemodynamic collapse. In such a catastrophic setting, we successfully achieved immediate stabilization by implantation of an Impella CP device (Abiomed). After 1 day of Impella CP assistance, we successfully performed elective transfemoral aortic revalving through the same femoral access by facilitating device crossing and hemostasis with transradial balloon peripheral angioplasty and by practicing a novel technique we called “pump rewiring.” Conclusion. This case example demonstrates how a tailored step-by-step strategy including PCI, BAV, peripheral angioplasty, percutaneous ventricular assistance, and transcatheter aortic valve implantation (TAVI) allowed the successful treatment of a critical patient with CS. Impella CP could be considered an effective bridge to TAVI in patients developing aortic regurgitation after BAV, since maintaining arterial access can be achieved using the pump-rewiring technique.

J INVASIVE CARDIOL 2016;28(1):E1-E5

Key words: surgical risk, TAVI, TAVR, complications, cardiogenic shock

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Cardiogenic shock (CS) complicating acute myocardial infarction is associated with a mortality rate of 40%-50% despite early revascularization and adjunctive therapies, but patients who survive the acute phase may have good long-term outcomes.¹ Thus, any improvement in the early management of such patients has the potential to substantially affect quantity and quality of life. 

The optimal treatment of CS occurring in the presence of acute coronary syndromes, severe aortic stenosis, and poor left ventricular (LV) function has not been established. Indeed, even in stable clinical scenarios, the association of severe aortic stenosis and severe LV dysfunction is associated with poor surgical outcome.²

In recent years, a number of novel percutaneous devices and techniques in the field of LV assistance have provided novel management opportunities and have somewhat changed the general approach. Indeed, percutaneous procedures have the characteristic of allowing “staged” interventions, wherein it’s possible to plan the different steps according to the evolving clinical scenario of critical patients with multiple diseases.

We report the case of a patient with severe aortic stenosis presenting with CS in the context of non-ST elevation acute myocardial infarction in whom percutaneous coronary intervention (PCI), balloon aortic valvuloplasty (BAV), percutaneous ventricular assistance, peripheral balloon angioplasty, and transcatheter aortic valve implantation (TAVI) were performed in different steps. This case also highlights the potential role of percutaneous ventricular assistance with the novel Impella CP pump (Abiomed) as an effective bridge to TAVI in hemodynamically unstable patients.

The pump-rewiring technique. A 73-year-old woman with non-ST elevation acute myocardial infarction presented to the emergency department of our hospital complaining of worsening shortness of breath and chest tightness. She had a known history of bilateral lower-limb peripheral disease (Leriche-Fontaine IIB) and bilateral carotid artery disease (with previous left carotid surgery). She had a 4-year history of chronic exertional angina, which was previously investigated by a coronary angiogram showing a chronic total occlusion (CTO) of the right coronary artery (RCA), which was addressed with medical management. During the last year, as part of her regular follow-up, the patient underwent an echocardiogram that showed moderate-to-severe LV dysfunction and a severely narrowed aortic valve (estimated aortic valve area, 0.8 cm²). Elective cardiac surgery for aortic valve replacement was suggested; the patient refused.

On hospital admission, the patient had clinical signs of pulmonary edema, blood pressure of 75/50 mm Hg, and persistent chest pain. Intravenous infusions of furosemide and inotropic agents were started, but intubation was thereafter necessary due to ongoing respiratory fatigue. Her first electrocardiogram (ECG) was unremarkable (Figure 1A), but the second ECG, performed after 2 hours, showed anterolateral ST depression (Figure 1B). Troponin-T assay was positive. She was referred to our catheterization laboratory to undergo urgent coronary angiography.

Coronary angiography was performed via left femoral access (which was the only palpable arterial access) and revealed a critical ostial left main (LM) stenosis, apart from the known RCA-CTO (Figure 2). The case was immediately discussed with the cardiac surgeons, but cardiac surgery in the context of hemodynamic instability and ongoing ischemia was considered a prohibitive risk. Thus, emergency PCI was selected as the first treatment in order to try and stabilize hemodynamics by relieving myocardial ischemia. Due to right femoral pulse weakness (in the setting of known peripheral arterial disease), we decided to perform emergency LM-PCI with no intraaortic balloon pump support. An extra-backup 3.5 guide catheter was selected to quickly cannulate the LM, and lesion predilation with a 4.0 non-compliant balloon was then performed. A zotarolimus-eluting stent was implanted into the LM. Angiographic final result was excellent (Figure 2), ST-segment depression resolved, and hemodynamics started to improve, so the patient was transferred to our critical care unit. During the following 24 hours (day 1), she had a stable systolic blood pressure of 110 mm Hg (under noradrenalin infusion) and extubation was successfully performed. On day 2, in the absence of any signs of recurrent ischemia, a significant drop of BP and a global worsening of pulmonary edema (pulmonary artery pressure monitoring by Swan-Ganz catheter, 68 mm Hg) were noticed, so the decision was made for urgent BAV and a bail-out insertion of percutaneous ventricular assistance device. The patient was brought back to the catheterization laboratory, and her 6 Fr sheath in the left femoral artery was exchanged with a 10 Fr sheath to perform BAV. Right femoral venous access was obtained and a 6 Fr sheath was inserted to accommodate a temporary pacemaker. A 6 Fr Amplatz left 1 diagnostic catheter and a straight wire were used to access the LV. Under high-rate temporary pacing, BAV was successfully performed with a 20 cm balloon and peak-to-peak ventricular-aortic pressure gradient was reduced from 50 mm Hg to 25 mm Hg. Unfortunately, a significant aortic regurgitation developed as a result, with equalization of LV end-diastolic pressure and aortic diastolic pressure and 3+/4+ regurgitation at aortography. Systolic BP immediately started decreasing. Thus, we promptly proceeded to Impella CP assist device insertion. The 10 Fr sheath was exchanged with the Impella 14 Fr sheath. The Impella pump was then advanced over the dedicated 0.014˝ guidewire into the LV (Figure 3). The pump output was set at its maximal speed. The sheathless Impella catheter was fixed in position. An immediate improvement of hemodynamic parameters was observed (systolic blood pressure increased from 75 mm Hg to 105 mm Hg, pulmonary artery systolic blood pressure decreased from 68 mm Hg to 45 mm Hg) and the patient was moved back to the critical care unit, where she was kept under strict observation to unmask any possible sign of critical limb ischemia. After collegial discussion, a TAVI procedure was planned as a definitive way to treat her aortic disease (residual gradient, relevant post-BAV regurgitation). The morning after (day 3), transfemoral TAVI was performed. Left radial access was obtained as the ancillary approach to guide the procedure.³ Indeed, through left radial approach, a 6 Fr, 125 cm MP catheter was used to perform iliofemoral angiography, which showed a diffuse disease of both axes with tight calcific stenosis of the right external iliac artery and a moderate-to-severe stenosis of the left external iliac artery, which was chosen as the best axis to perform the intervention. To allow safe Impella CP removal and TAVI performance through the same (left) iliac artery axis, transradial peripheral angioplasty was performed (Figure 4). A V18 ControlWire (Boston Scientific) was positioned into the left superficial femoral artery, and 5.5 x 20 mm and 7 x 30 mm Falcon Grande balloons (Medtronic) were inflated into the left external iliac artery (Figure 4) with the Impella catheter still in place. The Impella CP catheter was then pulled back until the pump outflow hub was visible outside the skin in order to perform the “pump-rewiring” technique. To do this, a 0.014˝ Choice Extra Support guidewire (Boston Scientific) – the “access maintenance” wire – was inserted through the pump lumen to reach the inflow hub, which was inside the artery (Figure 4). Once the wire was successfully advanced into the iliac axis, low-pressure percutaneous transluminal angioplasty balloon inflation and manual compression were used to avoid bleeding from the entry site during the following steps needed to exchange the Impella with the TAVI sheath. Indeed, a 5 Fr right catheter was advanced over the coronary guidewire, which was then exchanged for a high-support 0.035˝ wire to allow 18 Fr sheath placement. Then, a 26 mm CoreValve (Medtronic) was successfully implanted (Figure 5).

At the end of the procedure, the TAVI sheath was removed and the left radial approach was used to facilitate hemostasis by prolonged balloon inflation during manual compression. No bleeding was noticed at the entry site, but a complete occlusion of the left common femoral artery was detected at the angiographic control (Figure 6). Thus, over the 0.018˝ wire that was still in place as a “sentinel wire,” 3 x 150 mm and 5 x 150 mm, 180 cm shaft Pacific Extreme balloons (Medtronic) were sequentially advanced from the left radial access and inflated, finally achieving restoration of anterograde flow (Figure 6). 

The patient was transferred to the critical care unit after the procedure; she had an uneventful subsequent clinical course. An echocardiogram control performed 4 days later showed good aortic prosthesis function. Five days after the procedure, she was transferred to the ward, where she had to face a urinary infection before successful discharge at 27 days after admission. The patient went back to her daily life and so far (6 months after treatment) she has had no major adverse events.

Discussion

We reported the successful percutaneous management of a critical patient who presented with CS during acute coronary syndrome in a setting of ischemic cardiomyopathy, severe LV dysfunction, and severe aortic stenosis. Therapeutic options for such patients are limited, and the prognosis is often poor. Surgical aortic valve replacement in an emergency setting may be considered, but reported mortality is as high as 30%-50%.⁴ Once the surgical option is ruled out, percutaneous management is usually considered. When planning a percutaneous rescue of patients with various problems, different procedures may be considered (intraaortic balloon pump, BAV, PCI, TAVI, cardiac assistance, etc). Of note, an interesting advantage of percutaneous management is represented by the possibility to manage the patient in different steps according to the evolving clinical scenario, given the presence of suitable arterial access sites. From this perspective, the reported case looks very representative, since eventually performing complex combined procedures would have been extremely challenging (mainly due to severe iliac-femoral disease), and failed attempts during the initial management would not have been tolerated. Moreover, the anticipation of possible complications and their prompt management with appropriate strategies may be pivotal. According to our experience, extreme caution in the management of severe calcific peripheral disease may be crucial for the successful completion of percutaneous procedures requiring the advancement of bulky devices into the lower-limb arterial axes.⁵ In particular, the systematic performance of peripheral angiography, the use of alternative ancillary accesses (eg, radial), and the availability of peripheral angioplasty equipment and techniques may all combine to allow safer crossing, hemostasis achievement, and patency preservation of iliofemoral arteries.⁵ Furthermore, we planned in advance to use cardiac assistance with Impella as a back-up for the possible development of aortic regurgitation during BAV. Indeed, we have been able to insert the Impella catheter through the same arterial access immediately after BAV to facilitate bridging to TAVI. To the best of our knowledge, this sequence of interventions has never been reported, and aortic stenosis is usually considered a contraindication for Impella pumps due to the need for crossing a diseased valve and the risk of exacerbating valve dysfunction. Yet, recent experiences from different groups suggest that Impella may help manage patients with aortic stenosis and poor LV function undergoing percutaneous interventions.^6-8 The immediate clinical stabilization achieved and the consistent hemodynamic benefit documented during the cardiac assistance period both suggest that the high flow provided by the Impella CP catheter (which has never been used in such a clinical setting) should be considered effective even in the presence of more complex clinical scenarios. In addition, using a pump-rewiring technique (Figure 4), Impella removal and transfemoral TAVI have been successfully performed using the same femoral access. A step-wise approach in performing complex percutaneous procedures is possible only in the presence of good peripheral arteries, which could be safely and quickly cannulated by the operators. To do this, “ancillary” radial access was definitely useful in guiding the procedure and managing complications. However, since only one femoral artery was suitable for the intervention, we needed a quick and effective approach to perform TAVI in a patient with an unacceptably high surgical risk. The pump-rewiring technique undoubtedly offers a quick and easy solution in complex clinical scenarios where femoral anatomy is not known, or as in our case, where there is only one possible access to perform a high-risk intervention. 

References 

1.    Hochman JS, Sleeper LA, Webb JG, et al. Early revascularization in acute myocardial infarction complicated by cardiogenic shock. SHOCK Investigators. Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock. N Engl J Med. 1999;341:625-634.

2.    Conolly MH, Oh JK, Schaff HV, et al. Severe aortic stenosis with low transvalvular gradient and severe left ventricular dysfunction: result of aortic valve replacement in 52 patients. Circulation. 2000;101:1940-1946.

3.    Cortese B, Trani C, Lorenzoni R, et al. Safety and feasibility of iliac endovascular interventions with a radial approach. Results from a multicenter study coordinated by the Italian Radial Force. Int J Cardiol. 2014;175:280-284.

4.    Hutter AM, De Sanctis RW, Nathan MJ, et al. Aortic valve surgery as an emergency procedure. Circulation. 1970;41:623-627. 

5.    Dato I, Burzotta F, Trani C, Crea F, Ussia GP. Percutaneous management of vascular access in transfemoral transcatheter aortic valve implantation. World J Cardiol. 2014;6:836-846.

6.    Londono JC, Martinez CA, Singh V, O’Neill WW. Hemodynamic support with Impella 2.5 during balloon aortic valvuloplasty in a high-risk patient. J Interv Cardiol. 2011;24:193-197.

7.    Martinez CA, Singh V, Heldman AW, O’Neill WW. Emergent use of retrograde left ventricular support in patients after transcatheter aortic valve replacement. Catheter Cardiovasc Interv. 2013;82:E128-E132.

8.    Spiro J, Venugopal V, Raja Y, Ludman PF, Townend JN, Doshi SN. Feasibility and efficacy of the 2.5 L and 3.8 L impella percutaneous left ventricular support device during high-risk, percutaneous coronary intervention in patients with severe aortic stenosis. Catheter Cardiovasc Interv. 2015;85:981-989. Epub 2014 Jan 31.

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From the Interventional Cardiology Unit, Department of Cardiovascular Medicine, Catholic University of the Sacred Heart, Rome, Italy.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Burzotta reports personal fees from Medtronic, Abiomed, and St. Jude. Dr Trani reports Abiomed speaker fees. Dr Nerla reports no conflicts of interest regarding the content herein.

Manuscript submitted May 11, 2015 and accepted May 12, 2015.

Address for correspondence: Francesco Burzotta, MD, PhD, Institute of Cardiology, Catholic University of the Sacred Heart, Largo A. Gemelli 8, 00168 Roma, Italy. Email: f.burzotta@rm.unicatt.it