Friday Morning, May 13, 1960
9:00 A.M. Scientific Session: REGULAR PROGRAM Napoleon Room
30. A
Five Year Follow-up Study of Closed Mitral Valvulotomy.
J. Gordon Scannell, John F.
Burke (by invitation), and
Farrokh Saidi (by invitation), Boston, Mass.
In the past there have been a number of reports on the
technique and immediate post operative results following closed mitral
valvulotomy. These reports as a rule have not discussed the long term results
which can be expected following closed operation. Evaluation of the closed
operation is clearly important in establishing the present indications of
open-heart procedures in mitral stenosis.
In order to gain a clear picture of long term results
that might allow prediction of an unsatisfactory outcome, the present status of
100 consecutive patients, who survived mitral valvulotomy at the Massachusetts
General Hospital more than five years ago, has been reviewed Particular
attention has been given to those patients who have required reoperation,
suffered late emboli and had reactivation of rheumatic heart disease.
Preliminary survey indicates a five year recurrence
rate of 5% - 10% and excellent long term results in two-thirds of the patients.
There have been a certain number of late emboli. The problem of recurrence is
particularly important since at the present time this has become an indication
for open-heart repair.
31. Valvuloplasty
for Acquired Aortic Stenosis.
Donald G. Mulder (by invitation), Albert A. Kattus (by invitation),
and William P. Longmire, Jr , Los Angeles, Calif.
Notable advances have been made in the past few years
in the surgical treatment of heart diseases. Satisfactory techniques are
available for the correction of most cardiac lesions. Although many procedures
have been advocated for the treatment of patients with acquired aortic
stenosis, none has been consistently successful. Any operation which does not
restore mobility to the heavily calcified and relatively fixed aortic valve
will be of limited value.
A new technique is presented by which the major
obstructing and immobilizing encrustations of calcium can be removed from the
valve cusps. This valvuloplasty not only increases the size of the aortic valve
orifice, but even more important from the functional standpoint, it restores mobility
to the valve cusps.
Eleven patients with acquired aortic stenosis have been
operated upon using this technique. There have been no operative or late
deaths. Several patients had been in congestive failure and all had been
symptomatic prior to operation. The systolic gradient across the aortic valve
preoperatively ranged from 36 mm. Hg. to 190 mm. Hg. with an average of 89 mm.
Hg. The gradient was completely abolished by operation in eight patients, with
an average residual gradient in the entire group of 7 mm. Hg. One patient with
associated severe aortic insufficiency has two prosthetic cusps reinforcing and
replacing his degenerated valve tissue. All patients have been symptomatically
improved and, except for those most recently operated upon, have returned to
work. The duration of follow-up is from two to eleven months
The early results of the treatment of acquired aortic
stenosis by the technique of valvuloplasty have been most encouraging. Until
such time as a suitable aortic valve prosthesis is available, we feel this
procedure warrants further trial.
32. Partial
and Complete Aortic Valve Prostheses in Advanced Aortic Insufficiency.
Dwight E. Harken, Warren J. Taylor (by invitation),
Harry S. Soroff (by invitation), Armand A. Lefemine (by invitation),
Sushil K. Gupta (by invitation), and Steven Lunzer (by invitation),
Boston, Mass.
Aortic insufficiency associated with minor degrees of
left ventricular chamber enlargement has had encouraging correction with
partial and elsewhere even complete valve prostheses at open operation.
The problem of prostheses and open correction of aortic
insufficiency when the ventricle is markedly dilated and in failure presents a
very difficult and much more formidable challenge. A primary consideration is
that the increased chamber diameter aggravates the failure promptly if any
resistance is added at the valve site La Place's law (P = T/r4)explains
this difficulty when any valve resistance (a function of P) markedly increases
intramural tension (T) due to a large chamber radius (r). Thus prompt failure
can be expected to follow some of the currently described plastic techniques
and our experience supports this. This knowledge and experience influences the
type of prostheses, be they partial or complete. It has particular relevance to
the technique of extending cusps with Teflon and the hinge at the base.
A second cardinal problem is that of circulatory
support while the heart is resuming function after the repair. The conventional
constant flow arterial pump return results in the fragile dilated ventricle
having to work against ("buck") the pump. Left auricular "sumping", coronary
perfusion, etc., have made it possible to correct the aortic incompetence
associated with some of the more severe grades of myocardial insufficiency The
"bucking" problem can only be overcome by a combination of complete surgical
correction of valvular incompetence and coordinated pulsatile arterial pump
return. Such a pump is available in the Davol Birtwell pump. Experimental and
clinical application of this type of pump-oxygenator and valve prostheses in
advanced grades of myocardial dilatation and failure constitute the basis of
this communication.
33. The
Results of Surgical Treatment for Ventricular Septal Defect.
John W. Kirklin, Dwight C. Mcgoon, and James W. DuShane
(by invitation), Rochester, Minn.
By the date of the meeting of the Association, five
years of experience with the surgical treatment of ventricular septal defect
will have been had at the Mayo Clinic. At the time of submission of this
abstract, this comprises an experience with 355 cases.
In this study all cases are reviewed except those in
which the ventricular septal defect was a part of the tetralogy of Fallot or of
the complete form of common atrioventricular canal. Classification is into the
following groups:
1. Ventricular
septal defect with mild pulmonary hypertension.
2. Ventricular
septal defect with moderate pulmonary hypertension.
3. Ventricular
septal defect with severe pulmonary hypertension.
a. high
pulmonary blood flow/systemic flow ratio
b. moderately
elevated pulmonary blood flow/systemic flow ratio.
c. low
pulmonary blood flow/systemic flow ratio (one or less).
The
clinical and hemodynamic criteria for classification are discussed in detail.
Sixty per cent of the cases in this series had severe pulmonary hypertension.
Over-all data on hospital mortality rate are
presented. In the year 1955, the hospital mortality rate was 20.0 per cent for
all cases of ventricular septal defect repaired while in the year 1959 (until
November 1), it was 5.3 per cent. Factors contributing to the reduction in
hospital mortality are analyzed.
Complications following the repair of ventricular
septal defect include the development of complete heart block and the
persistence of residual shunt after repair. Their incidence and methods by
which their occurrence can be minimized, are detailed.
34. The
Closure of Atrial Septal Defects Utilizing General Hypothermia: The
Effectiveness of Treatment as Determined by Cardiac Catheterization.
Andrew G. Morrow, Joseph W. Gilbert, Jr. (by invitation),
R. Robinson Baker (by
invitation), and N. Ferryman Collins
(by invitation), Bethesda, Md.
Thirty-six patients were operated upon at the National
Heart Institute during the period in which general hypothermia was employed to
permit the repair, by direct suture, of atrial septal defects. Cardiac
Catheterization was carried out postoperatively in 32 patients and the hearts
of three others, who died in the early postoperative period were examined at autopsy.
Of these 35 patients, 10 were demonstrated to have residual or recurrent
left-to-right shunts into the right atrium.
The repair was found to be incomplete in all of the
four patients who had sinus venosus defects with associated partial anomalous pulmonary
venous drainage. Five patients with residual shunts had ostium secondum defects
4 cm. in diameter or larger. In the remaining patient an unsuspected incomplete
A-V canal was present.
The brevity of the period of circulatory interruption
permitted by hypothermia, even with coronary perfusion, was found to impose
severe technical limitations It is considered that in the patients with ostium
secundum defects the failures of surgical treatment could have been obviated
had sufficient time been available for the insertion of a prosthesis,
permitting closure of the defects without tension. In the patients with sinus
venosus defects the pulmonary venous drainage could have been diverted into the
left atrium in this manner.
This high incidence of incomplete repair has led to the
abandonment of hypothermia and the adoption of cardiopulmonary bypass in the
surgical management of all patients with atrial septal defects. The value of
detailed postoperative studies in assessing the effectiveness of a cardiac surgical
procedure is also illustrated
35. Elective
Cardiac Arrest Using Selective Cardiac Hypothermia.
David M. Long, Jr. (by invitation), Laurence P. Sterns (by invitation),
Vincent L.
Gott (by invitation), Robert H. Deriemer (by invitation),
and C. Walton Lillehei, Minneapolis,
Minn.
Selective cardiac hypothermia has been employed
successfully experimentally and clinically as a method for providing routine
elective cardioplegia and as a method for providing maximum protection to the
myocardium during aortic valvular surgery. Only short periods of anoxic arrest
or chemical cardioplegia are tolerated without the production of myocardial
insufficiency or necrosis. Uneven distribution of the coronary perfusate and
certain technical factors limits the usefulness of continuous retrograde and
antegrade coronary perfusion. Extensive clinical experience has demonstrated by
objective measurements the significant superiority of selective cardiac
hypothermia as compared with the above methods
The method is simple. Gardiopulmonary bypass is
employed using the bubble oxygenator and Sigmamotor pump. A separate line from
the bottom of the oxygenator is used to pump oxygenated blood through a
disposable cooling unit which will be described. The temperature of the
arterial blood is lowered to 5° to 12° C. After clamping of the ascending
aorta, cold blood is perfused through the coronary arteries. The exact method
utilized depends upon the lesions present and these will be described. The
myocardial temperature is decreased to 15° to 17° C within 3 to 5 minutes
Animal experiments were designed to evaluate the
tolerance of the myocardium to coronary perfusion with cold blood and to test
effects of interruption of the coronary flow of the hypothermic heart for
intervals up to one hour. Combinations of selective cardiac hypothermia and
chemical cardioplegia were also studied. Comparisons of these methods were made
by measuring coronary venous pH and lactic acid levels before and after
hypothermia. The methods were also compared with regard to survival of the dogs
and histologic changes in the myocardium.
Selective cardiac hypothermia has been employed to date
in 100 patients with a wide variety of cardiac lesions. Myocardial biopsies of
human hearts subjected to potassium citrate arrest and selective cardiac
hypothermia have been analyzed for lactic acid, glucose, adenosine
tri-phosphate and phosphocreatine levels before and after cardioplegia.
36. Open
Heart Surgery Using Deep Hypothermia Without an Oxygenator.
Archer S. Gordon (by invitation), Bertrand W. Meyer, and
John C. Jones, Los Angeles, Calif.
The ultimate goal in extracorporeal circulation for
intracardiac surgery is to reduce and simplify the mechanical equipment to its
barest essentials. We have accomplished this by performing all types of
prolonged open heart surgical procedures using only two mechanical pumps and a
heat exchanger (no oxygenator or special monitoring equipment is required).
Using temperatures down to 10° C., this has allowed us to operate in a
completely quiet, bloodless field for periods up to one hour on such lesions as
ventricular septal defects, tetralogy of Fallot, total anomalous pulmonary
venous drainage, aortic stenosis, etc.
The advantages of this technique include the following: (1) Requires a
minimum amount of equipment (only two pumps and heat exchanger), (2) Requires
only 1200 cc. of blood to prime the system; (3) Cardiac arrest results from
cold - neither cardioplegic drugs nor anoxic arrest are used; (4) Circulatory
standstill is used during the intracardiac surgery and provides an absolutely
quiet, bloodless field; (5) Periods up to several hours can be used safely, if
required, for intracardiac repairs.
Laboratory and clinical studies reveal freedom from
problems associated with hemolysis, acidosis, perfusion rates, clotting
mechanisms, and blood volume balance. Blood aspirated from the open heart is
minimal and may be discarded or reused.
Studies of oxygen utilization have provided a
determination of the safe period of circulatory occlusion at any given
temperature. Thus, the temperature can be selected for each patient on the
basis of the time requirements for his case. If it becomes necessary for
circulatory occlusion to exceed the time allowable at the temperature selected,
brief reperfusion allows prolonged extension of this period.
This simple, versatile, safe procedure appears to
provide the best approach for the correction of most intracardiac lesions.
