New heart pumps offer hope to sickest patients
Jacob Abraham, M.D.
Cardiologist, Providence St. Vincent Heart Clinic-Cardiology
Published June 2011
Cardiogenic shock is a life-threatening complication of myocardial infarction, cardiomyopathy and ventricular arrhythmias. Prompt diagnosis and restoration of cardiac output are essential to support end-organ function, enable myocardial recovery or stabilize the patient for definitive therapies.
Cardiogenic shock is the major cause of death in MI, with in-hospital mortality rates greater than 50 percent, despite urgent coronary revascularization and insertion of an intra-aortic balloon pump, or IABP.
Historically, the IABP has been the most common mode of mechanical circulatory support for cardiogenic shock. However, the pump’s significant shortcomings are its limited hemodynamic support, dependence on a stable cardiac rhythm and inability to support the right ventricle.
New temporary cardiac support devices now available at Providence hospitals circumvent the limitations of the IABP and already have been used to “rescue” moribund patients who otherwise would have died.
The TandemHeart from CardiacAssist Inc. is a continuous-flow (i.e., non-pulsatile) ventricular assist device approved for short-term circulatory support. The device can be placed percutaneously in the catheterization lab by cardiologists or directly into the heart by cardiac surgeons.
Oxygenated blood from the left atrium is actively drained by the pump, which sits outside the body, and is delivered to a major artery. The external circulation of blood effectively bypasses the heart, thereby reducing cardiac work and “resting” the heart.
See the device in motion
The pump is connected to a console that adjusts its rotational speed, enabling flows of 5 liters per minute with percutaneous placement or 8 liters per minute with operative placement.
Pump placements yield results
In October 2010, Ethan Korngold, M.D., and Richard Sohn, M.D., from Providence St. Vincent Heart Clinic-Cardiology performed the first percutaneous TandemHeart insertion in the Northwest at Providence St. Vincent Medical Center to support a previously healthy 52-year-old man with non-ischemic cardiogenic shock.
After five days of device support, and despite complications of dialysis-dependent renal failure and shock liver, he survived to enjoy complete recovery of organ function and returned to work full-time.
The first operative placement in the Northwest was performed at Providence Portland Medical Center by The Oregon Clinic’s Gary Ott, M.D., to enable a patient with post-cardiotomy shock to survive to discharge.
Twelve pump implants have since been performed by cardiologists and surgeons at both hospitals for a variety of indications, including high-risk percutaneous coronary intervention, isolated right and bi-ventricular support, and as a bridge to long-term ventricular-assist device placement or definitive cardiac surgery.
The Providence experience parallels that of the Texas Heart Institute. In a recent report, the authors describe use of the TandemHeart in 117 patients, including 56 patients undergoing CPR before or during device implantation. Six-month survival for the entire cohort was 45 percent, and a remarkable 36 percent in the subgroup requiring CPR.
In short, a new era of device therapies has been ushered in at Providence hospitals in the Portland area. Besides the TandemHeart, Providence recently implanted HeartMate II, a long-term ventricular-assist device used as an alternative to cardiac transplantation. In appropriately selected patients with severe heart failure, these heart pump technologies offer new hope.
Clinical articles by Jacob Abraham, M.D.