Right Subclavian Artery Cutdown for Implantation of Impella 5.0
- A 52-year-old man with his first presentation in heart failure, NYHA class IV.
- Transthoracic echocardiogram showed severely dilated left ventricle (LV) with global hypokinesia, left ventricular ejection fraction (LVEF) 20%, moderate mitral regurgitation.
- Coronary angiogram demonstrated no significant coronary artery disease.
- Congestion initially improved on intravenous diuretics.
- Low cardiac output on milrinone infusion, 0.3 mcg/kg/min.
- Mild liver function tests derangement.
- severely dilated LV with severe systolic dysfunction, biplane EF = 14%; moderate mitral regurgitation.
- normal right ventricular (RV) size with impaired systolic function; minimal tricuspid regurgitation; PASP of 22 mm Hg + JVP.
Etiology of cardiogenic shock is diverse and mainly includes myocardial infarction, postcardiotomy cardiogenic shock, and chronic heart failure. Its management depends essentially upon its severity. Inotropes are the first line of treatment and are usually sufficient to manage mild cardiogenic shock. Severe shock, particularly involving biventricular failure, often requires utilization of venoarterial extracorporeal oxygenation. A significant number of patients that fall in between this gap, especially those with the isolated left ventricular failure can be helped with the less invasive temporary left ventricular assist device (LVAD), Impella® (Abiomed Europe GmbH, Aachen, Germany). The Impella LVAD is a microaxial ventricular support device designed to provide temporary support in the setting of left ventricular failure, and it can be used for high-risk percutaneous coronary intervention, myocardial recovery, as a bridge to decision, or as a bridge to a long-term solution such as heart transplantation or LVAD. Absolute contraindications are significant aortic regurgitation and previous mechanical aortic valve replacement. The presence of an LV mural thrombus is also a relative contraindication.
The device is inserted via a peripheral artery under fluoroscopy or transesophageal echocardiography (TEE) guidance to cross the aortic valve, and it is placed in such a way that the inflow and pump remain in the left ventricle while the outflow stays in the ascending aorta. Impella 5.0 offers a continuous flow up to 5 L/min and is CE marked for up to 10 days of use in Europe . In addition, it offloads the left ventricle to increase cardiac output and improvement in end-organ perfusion, abating requirement of inopressors. Engström and colleagues emphasize superior survival in the patients supported with the Impella 5.0 compared to the Impella 2.5 due to its ability to provide superior flows . However, the greater flow of the Impella 5.0 over its predecessors is achieved at a cost of a bigger diameter, and therefore it requires open cutdown of the vessel for its insertion. Femoral artery is a familiar and convenient access, given that a significant number of patients receive the device in the catheterization lab following primary coronary intervention. Subclavian artery access offers a longer duration of support along with prompt ambulation of the patient. This is more relevant in patients with chronic advanced heart failure with acute decompensation who require bridging to substantive therapy in terms of heart transplant or long-term left ventricular assist device. In a recently published series, the mean duration of Impella 5.0 support implanted via the subclavian artery cutdown was 17 (range, 1 to 71) days . The authors demonstrate their technique of Impella 5.0 insertion via the subclavian artery, seasoned over a period of time along with some pearls and pitfalls.
- Expose the right subclavian artery via a subclavicular incision.
- Perform an end-to-side anastomosis of the 10 mm silver-impregnated polytetrafluoroethylene (PTFE) tube graft to the subclavian artery.
- Tunnel the PTFE graft under the skin bridge.
- Place the introducer sheath provided with Impella® 5.0 kit into the PTFE graft.
- Pass guidewire 1 (3 mm J TEF Guidewire 240 cm x 0.035 DBL Heavy Duty, AngioFlex KIMAL, England) through the introducer sheath into the left ventricle, crossing the aortic valve under the fluoroscopy or TEE guidance.
- Introduce pigtail (6F, Pigtail 110 cm length, Cordis, Switzerland) over the guidewire 1 into the left ventricle.
- Replace guidewire 1 with guidewire 2 (provided with Impella 5.0 kit), utilizing the pigtail as a guide.
- Remove pigtail, leaving guidewire 2 in the left ventricle.
- Pass the Impella 5.0 device over guidewire 2 through the introducer sheath, into the PTFE graft, and across the aortic valve into the left ventricle.
- Position the device under TEE monitoring and using placement signal on the Impella controller, keeping inflow and pump inside the left ventricle while outflow remains above the aortic valve. Remove guidewire and start the device at low speed, increasing progressively during monitoring. Titrate device flow according hemodynamic parameters, with speed no higher than P7-P8 to avoid hemolysis.
- Cross-clamp the PTFE graft and remove the introducer sheath, keeping the Impella in place.
- Pass the two struts over the device driveline into the tube graft, and secure the device to the graft with silk ties at the level of the struts. Placing the struts is necessary not only to achieve hemostasis but also to adjust the position if needed at a later stage.
- Lock the device and fix it to the skin with silk stitches.
- Silver impregnated PTFE vascular graft (10 mm Silver Graft, B. Braun, Germany)
- Wire 1 (3 mm J TEF Guidewire 240 cm x 0.035 DBL Heavy Duty, AngioFlex KIMAL, England)
- Wire 2 (provided with Impella 5.0 kit)
- Pigtail (6F, Pigtail 110 cm length, Cordis, Switzerland)
- Fluoroscopy or TEE
Tips and Pitfalls
- Use the silver impregnated PTFE tube graft, as it has less tendency for anastomotic bleed and graft sweating. It is also designed for prophylactic long-term protection against vascular graft infections.
- Keep the tube graft and the tunnel short (approximately 8 - 10 cm). Also, make sure that the tunnel is wide enough to accommodate the 10 mm tube graft and smooth passage of the struts.
- The most difficult and time-consuming part of the operation when using TEE monitoring in a non-hybrid theater, is passage of the guidewire across the aortic valve into the left ventricle utilizing the guidewire provided by the company as a part of the device kit. The authors have adopted a “two wires and a pigtail” technique, which involves passage of a J guidewire, which allows to easily cross the aortic valve) followed by the Impella guidewire (over which the Impella 5.0 can be threaded) with a bridging pigtail.
- It is of utmost importance that the wire, once entered into the left ventricle crossing aortic valve, should not be moved inadvertently until the Impella crosses the aortic valve.
- It is essential to hold the guidewire steady and fixed to an immobile surface while moving the Impella device over it, as the wire may bend over the tip of the device occluding its passage through the PTFE tube graft.
- Apply cross-clamp on the tube graft prior to removal of the introducer sheath, as it prevents bleeding while placing the struts and holds the device securely in place.
- Ensure a proper position of the Impella device across the aortic valve under imaging guidance as the inappropriate placement of the device inside or outside the left ventricle significantly hampers its efficiency to offload the left ventricle and to provide forward flow.
- Locking the device and securing it to the PTFE graft as well as to the skin is of paramount importance to avoid its displacement across the aortic valve.