Peer M. Portner

Bio: Peer M. Portner is an academic researcher from Stanford University. The author has contributed to research in topics: Transplantation & Ventricular assist device. The author has an hindex of 25, co-authored 63 publications receiving 2829 citations.

Implantable infusion device.

Abstract: An improved implantable infusion device for delivering precisely regulated doses of fluid into the body of a patient. The device utilizes a resilient non-compliant pump bellows (13) that is directly coupled by a gear train (15, 17, 19, 21) to a motor (23). The bellows (13) is biased toward the expanded position and this factor, combined with the mechanical inertia of the gear train (15, 17, 19, 21) substantially eliminates the danger of an overdose of infusate being released into the patient.

Mechanical circulatory support for advanced heart failure: effect of patient selection on outcome.

Abstract: Background—Use of wearable left ventricular assist systems (LVAS) in the treatment of advanced heart failure has steadily increased since 1993, when these devices became generally available in Europe. The aim of this study was to identify in an unselected cohort of LVAS recipients those aspects of patient selection that have an impact on postimplant survival. Methods and Results—Data were obtained from the Novacor European Registry. Between 1993 and 1999, 464 patients were implanted with the Novacor LVAS. The majority had idiopathic (60%) or ischemic (27%) cardiomyopathy; the median age at implant was 49 (16 to 75) years. The median support time was 100 days (4.1 years maximum). Forty-nine percent of the recipients were discharged from the hospital on LVAS; they spent 75% of their time out of the hospital. For a subset of 366 recipients, for whom a complete set of data was available, multivariate analysis revealed that the following preimplant conditions were independent risk factors for survival after LVAS implantation: respiratory failure associated with septicemia (odds ratio 11.2), right heart failure (odds ratio 3.2), age .65 years (odds ratio 3.01), acute postcardiotomy (odds ratio 1.8), and acute infarction (odds ratio 1.7). For patients without any of these factors, the 1-year survival after LVAS implantation including the posttransplantation period was 60%; for the combined group with at least 1 risk factor, it was 24%. Conclusions—Careful selection, specifically implantation before patients become moribund, and improvement of management may result in improved outcomes of LVAS treatment for advanced heart failure. (Circulation. 2001;103: 231-237.)

Power supply for body implant and method for operation

Abstract: A power supply system to operate an implanted electric-powered device such as a blood pump. A secondary coil having a biocompatible covering is implanted to subcutaneously encircle either the abdomen or the thigh at a location close to the exterior skin. The secondary coil is electrically interconnected with an implanted storage battery and the blood pump. A primary coil of overlapping width is worn by the patient at a location radially outward of the secondary coil. An external battery plus an inverter circuit in a pack is attached to a belt having a detachable buckle connector which is conventionally worn about the waist. Efficient magnetic coupling is achieved through the use of two air-core windings of relatively large diameter.

Long-Term Use of a Left Ventricular Assist Device for End-Stage Heart Failure

Abstract: Background Implantable left ventricular assist devices have benefited patients with end-stage heart failure as a bridge to cardiac transplantation, but their long-term use for the purpose of enhancing survival and the quality of life has not been evaluated. Methods We randomly assigned 129 patients with end-stage heart failure who were ineligible for cardiac transplantation to receive a left ventricular assist device (68 patients) or optimal medical management (61). All patients had symptoms of New York Heart Association class IV heart failure. Results Kaplan–Meier survival analysis showed a reduction of 48 percent in the risk of death from any cause in the group that received left ventricular assist devices as compared with the medical-therapy group (relative risk, 0.52; 95 percent confidence interval, 0.34 to 0.78; P=0.001). The rates of survival at one year were 52 percent in the device group and 25 percent in the medical-therapy group (P=0.002), and the rates at two years were 23 percent and 8 percent...

2013 ACCF/AHA Guideline for the Management of Heart Failure: Executive Summary A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines

Abstract: The medical profession should play a central role in evaluating the evidence related to drugs, …