This memo is sent for your thoughtful consideration in view of (1) the charge for me to review technological developments
in NHLI, (2) the charge to me to act as coordinator of such developments in NHLI, and (3) the phenomenal pressures being put
upon the CDB of DHVD of NHLI by some contractors.
An example of the lack of effective expert guidance in the direction of work in the laboratories of contractors is that of
provision of left ventricular assistance when needed after open-heart operations at the end of which the left ventricle is
not yet able to assume the full burden of pumping. Protests from NHLI were ignored that utilization of implanted pumps for
support of a duration of less than two weeks would impose a second major operation upon an already critically ill patient.
Protests from NHLI were also ignored that a procedure such as that used by DeBakey a half-dozen years ago, using blood-bearing
conduits to the outside pump, would be safer because the supporting procedure could be terminated by a trivial procedure under
Over these protests, the pressures from the developers were overweening, and the NHLI submitted first to a conference on Oct.
28, 1973, limited to the implanted pumps of the concerned contractors, and more recently, in drawing up guidelines for clinical
trial of the LVAD, to a shortening of the period of demonstrably reliable use to 2 weeks, which may be expected to leave the
patient still in the critical post operative period after his open-heart operation.
Against this background, contrast the work of Frank Spencer a decade ago, in which he used the findings of Senning and Dennis
on left heart bypass with the revision that he used a vascular graft placed at the end of the open-heart operation to lead
blood from the left atrium to the outside, to be pumped by a pump external to the body back through the arterial cannula used
for extracorporeal perfusion. There was salvage of a patient who had displayed myocardial inadequacy after otherwise successful
cardiac repair. Two further patients were salvaged by pumping from the left ventricle to the aorta for an hour while the chest
had not yet been closed, just as Crafoord had done eight years earlier.*
*F.C. Spencer, Ben Eiseman, J.K. Trinkle, and N.P. Rossi; Assisted circulation for cardiac failure following intracardiac
surgery with cardiopulmonary bypass. J. Thor. and Cardiovasc. Surg. 49: 56, 1965.
Contrast again with the recent work of Dr. Robert Litwak, who fashioned catheters of quarter-inch internal diameter and precisely
fitting obturators of teflon and silicon rubber in the kitchen of the Mount Sinai Hospital of New York to permit shunting
from the left atrium to the ascending aorta of flows up to 2800 ml/min. On the termination of need for such left heart bypass
42 hours after the end of the operation, insertion of the obturators left a smooth teflon surface in the atrium and in the
aorta flush with the intime. This resulted in salvage of the patient, leaving the distal ends of the two catheters buried
in a subcutaneous position below the right costal margin in case support should again prove necessary. The patient is home
and doing nicely more than 4 months after his ordeal. This work was done in an orderly fashion in the animal laboratory with
money earned by Dr. Litwak, support for the project having been denied by the National Heart Institute (MDAP, 1969).
Clearly, in the knowledge of all this, the jingoistic prodding of the contractors to pursue the very short-term use of a bulky
device implanted in either the left chest* or the abdomen represents a search for application of a device rather than the
orderly search for a well-considered solution for a problem.
In view of the successes of Spencer and Litwak (although there were losses also) and in view of the concern with short-term
use of implanted devices which must be removed from a patient at a time when he still is far short of recovery from his initial
operation, the CDB is proposing to use $400,000 in FY 1975 and still larger amounts later to develop "Extra or paracorporeal
assist devices with percutaneous leads". This does not include development of the percutaneous leads, which is another
item of similar proposed cost.
From the point of view outside the active program, the following points seem clear:
1) Continued development of the left ventricle implantable assist device is worth while only if for the purpose of prolonged
or life-long utilization, and this would have to involve either a buried power source such as Pu238, perfection of safe percutaneous
leads, or a more practical means of electro-magnetic delivery of power than now exists.
2) For the purpose of support after open-heart operations for periods of less than two weeks, the present plan of implantation
of LVAD's with proven reliability no longer than that (or even twice that) which is under consideration is simply not
3) The expenditure of sums proposed to refine the method devised by Litwak does not appear at all necessary.
4) The phrenetic urge of some contractors to proceed quickly to clinical application of a device which is inappropriate to
the clinical situation is not ethically or morally correct and could lead to censure of the program and still further legislated
restrictions upon studies involving human subjects.
*It was even suggested by one contractor that the left lower pulmonary lobe be resected to provide space for the device.