Henry Ford Hospital Medical Journal

Volume 8 | Number 2 Article 6

6-1960

Temporary Aortic By-pass By Means Of AMechanical DeviceWalter H. Janke

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Recommended CitationJanke, Walter H. (1960) "Temporary Aortic By-pass By Means Of A Mechanical Device," Henry Ford Hospital Medical Bulletin : Vol. 8 :No. 2 , 134-137.Available at: https://scholarlycommons.henryford.com/hfhmedjournal/vol8/iss2/6

TEMPORARY AORTIC BY-PASS BY MEANS

OF A MECHANICAL DEVICE* WALTER H . JANKE, M.D.**

In operations of the aorta, in which temporary occlusion of the thoracic segment is done, the presence or absence of adequate collateral circulation must be considered in order to avoid ischemia of the lower parts of the body and the further complications of renal'^ and medullary damage.

The aortic coartation of the so-called adult type is almost the sole exception in which collateral circulation is usually maintained adequately, and the aortic clamping of the thoracic segment of the arorta is possible for a long period of time without danger of lower ischemia.

In other aortic operations the surgeon has three ways of avoiding the ischemia of the lower parts of the body: a) Short duration of aortic clamping, b) Use of Hypothermia, and c) Use of temporary by-pass systems.

a) Short duration of aortic clamping.' The aortic clamping alone is used when it is possible to predict that it will not be necessary to clamp the aorta for a long period of time. This is, of course, the easiest and quickest way. Nevertheless, there can always appear unexpected complications which prolong the time of aortic occlusion.

b) Use of Hypothermia.'-' This method prolongs the safe period of aortic occlusion, but the occurrence of ventricular fibrillation and other complications of hypothermia is a relative inconvenience.

c) Use of temporary by-pass systems. — By this means it is possible to prolong for a very long time the safe period of aortic occlusion. With this in mind homografts, heterografts, and plastic by-pass systems have often been used.'-''-''' A disadvantage, however, of suturing grafts that may be used in the by-pass systems is that some injury of the aorta itself may result which makes the operated area more difficult to repair. Another disadvantage is that the suturing procedure prolongs ihe operating time.

The purpose of this work is to describe the use in animals of a temporary by-pass by means of a mechanical device, with the view in mind of later human employment.

METHODS

This mechanical device consists of 3 pieces, (Figure 1) (a) Cannula with a fixed curved plate attached to the lower part, (b) Superior mobile curved plate, and (c) Nut.

The cannula is attached to a Tygon tube previous to the procedure, then the attached lower plate is introduced through a small aortic incision of 1 cm and the

*Work performed at the Surgical Research Laboratories, St. Luke's Hospital, Cleveland, Ohio. **Dr. Janke's present address is Division of General Surgery, Henry Ford Hospital.

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Mechanical device for temporary aortic by-pass, (a) Cannula with a fixed curved plate attached to the lower part, (b) Superior mobile curved plate, (c) Nut.

superior mobile plate is placed down, holding the aortic wall between the two plates, by tightening the nut.

Eleven healthy adult dogs were used. They were anesthetized by intravenous administration of sodium pentobarbital, and tracheal intubation tried out. After heparinization, the femoral artery was cannulated and connected to a manometer for blood pressure recording.

Two incisions in the left thorax were made, one through the fourth, and the other through the seventh interspace. The aorta was dissected free from the origin of the subclavian artery to the first pair of aortic intercostal arteries, and two aortic clamps were applied.

The fixed curved plate of the lower part of the cannula was inserted into the aorta through a 1 cm. incision in the clamped aorta. The Tygon tube was clamped and the aortic clamps removed.

The same procedure was done in the lower part of the thoracic aorta after ligating one pair of intercostal arteries.

The time employed in the insertion of the cannulas varied between one and eight minutes, the average being five minutes. Some details not taken into account made insertion time longer in the first experiments. In the last three dogs, this time was shortened to an average of 2.5 minutes.

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Janke

In all the experiments, mean femoral blood pressure was observed: a) Before applying the by-pass, b) Afer cross-clamping the aorta, c) With by-pass in place, d) With by-pass and aortic cross-clamping. Results are shown in Table I .

Table I

Mean Femoral Blood Pressure During the Experiments.

NUMBER OF

DOGS

BEFORE

BY-PASS

AORTA

CLAMPED

WITH BY-PASS AORTA

OPENED

BY-PASS ALONE AORTA CLAMPED IN THE MIDDLE

1 100 20 80 55 2 120 20 100 70 3 110 14 100 78 4 100 16 60 50 5 105 15 90 *80 6 95 18 90 *85 7 90 20 80 68 8 112 15 95 80 9 110 15 95 90

10 80 10 70 65 11 80 10 70 50

As can be noted in all the above mentioned experiences, the mean femoral blood pressure was maintained at an average of 70 mm. Hg., the lowest being 50 mm. Hg. which is within safety limits. In only two dogs blood was replaced (5 and 6); as can be seen in these experiments the blood pressure with the by-pass alone is very close to the pre-experimental level.

SUMMARY

In cases of operations of long duration on the thoracic aorta, it is often useful to employ a temporary by-pass system in order to avoid ischemia of the lower parts of the body. For this procedure homografts, heterografts, and plastic grafts has often been used.

The purpose of this work is to demonstrate in animals the use of a temporary aortic by-pass by means of a mechanical device with the view to latter human employment.

Experiences with eleven dogs are discussed in terms of ease of application and mechanical efficiency.

REFERENCES

1. Byron, F. X., Fields, J., Hood, R., and Foster, A.: Use of rigid prosthesis in vascular surgery, J. Thoracic Surg. 34:423, 1957.

2. Chamberiain, J. M., Klopstock, R., Parnassa, P., Grant, A. R., and Cincotti, J. J.: Use of shunts in surgery of thoracic aorta, J. Thoracic Surg. 31:251, 1956.

3. Cooley, D. A., and DeBakey, M. E.: Resection of the thoracic aorta with replacement by homograft for aneurysms and constrictive lesions, J. Thoracic Surg. 29:66:216, 1955.

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4. Cross, F. S., Hirose, Y., Jones, R. D., Hudack, S. S., and Kay, E. B.: Evaluation of mechanical shunt to bypass segments of the thoracic aorta including the arch, S. Forum 6:166, 1955 (cl956).

5. Cross, F. S., Kay, E. B., and Jones, R. D.: Simple shunting technique for surgery of aortic and pulmonary valves and proximal great vessels; experimental study, J. Thoracic Surg. 28:229, 1954.

6. DeBakey, M. E., Creech, O., Jr., and Morris, G. C, Jr.: Aneurysm of thoraco-abdominal aorta involving the celiac, superior, mesenteric and renal arteries. Report of 4 cases treated by resection and homograft replacement, Ann. Surg. 144:549, 1956.

7. DeBakey, M. E.: Changing concepts in thoracic vascular surgery, J. Thoracic Surg. 38:145, 1959.

8. Gerbode, F., Braimbridge, M., Osborn, J. J., Hood, M., and French, S.: Traumatic thoracic aneurysms: Treatment by resection and grafting with the use of an extracorporeal bypass. Surgery 42:975, 1957.

9. Johnson, J., Kirby, C. K., and Lehr, H. B.: Method of maintaining adequate blood flow through the thoracic aorta while inserting an aorta graft to replace an aortic aneurysm. Surgery 37:54, 1955.

10. King, H., and Shumacker, H. B., Jr.: Mechanical by-pass during thoracic aortic cross-clamping, J. Thoracic Surg. 34:485, 1957.

11. Lam, C. R., and Aram, H. H.: Resection of the descending thoracic aorta for aneurysm; report of use of homograft in case and experimental study, Ann. Surg. 134:743, 1951.

12. Mahorner, H., and Spencer, R.: Shunt grafts; method of replacing segments of aorta and large vessels without interrupting circulation, Ann. Surg. 139:439, 1954.

13. Schafer, P. W., and Hardin, C. A.: Use of temporary polythene shunts to permit occlusion, resection and frozen homologous graft replacement of vital vessel segments; laboratory and clinical study. Surgery 31:186, 1952.

14. Storey, C. F., Nardi, G. L., and Sewell, H. H.: Traumatic aneurysms of the thoracic aorta; report of 2 cases, one successfully treated by resection and graft replacement with the aid of a shunt, Ann. Surg. 144:69, 1956.

15. Szilagyi, D. E., Smith, R. F., and Whitcomb, J. G.: The kidneys in surgery of the abdominal aorta, A.M.A. Arch. Surg. 77:538, 1958.

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