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Left Heart Bypass: A Modified Technique
Left Heart Bypass: A Modified Technique LOUIS PIERUCCI, JR., M.D., F.A.C.S. * RUDOLPH C. CAMISHION, M.D., F.A.C.S.**
The indications for the application of left heart bypass for lesions of the thoracic aorta have been well documented. 1• 2 During operations upon the thoracic aorta, maintenance of blood flow into the distal aorta is necessary to prevent spinal cord and renal ischemia. During repair of coarctation of the aorta, the aorta may be clamped since blood flow into the distal aorta is provided by the extensive collateral circulation which is characteristic of the disease entity. The technical considerations usually consist of cannulation of the left atrium by way of the left auricular appendage and replacement of the blood drained from it back into the femoral artery in a retrograde manner. In our experiences with this technique prior to 1962 we occasionally found it difficult to achieve a predictable steady state perfusion. In view of this, two primary objections to this approach became apparent. The left auricular appendage in the heart without atrial enlargement is a very delicate, thin-walled structure varying in size and shape from patient to patient. Although its cannulation can be easily effected on most occasions, tears of this thin fragile appendage are not uncommon and we have seen several instances in which significant bleeding has occurred. In addition, since the left atrial cavity is a low pressure area, negative pressures of any significant degree tend to cause collapse of the atrial walls about the drainage holes of an intra-atrial drainage catheter. Transient outflow obstruction (fluttering) of the draining catheter occurs and this tends to interfere with a steady state of flow. As a result, the machine operator is presented with the necessity to make constant corrections in flow rates in order to maintain blood balance and the danger of air embolism is increased. Such a perfusion is comSupported in part by National Institutes of Health Grant E5339-07 *Assistant Professor of Surgery, Jefferson Medical College, Philadelphia, Pennsylvania **Professor of Surgery, Jefferson Medical College; Attending Surgeon, Jefferson Medical College Hospital, Philadelphia, Pennsylvania
Surgical Clinics of North America- Vol. 47, No.5, October, 1967
1275
1276
LOUIS PIERUCCI, RUDOLPH C. CAMISHION
monly attended by variations of flow which result in pressure fluctuations above and below the points of aortic occlusion. In an effort to obviate this occasional problem, a technique of left ventricular cannulation is used. The pericardium is opened widely and an avascular portion of the apex of the left ventricle is selected for cannulation. A horizontal mattress suture of 0 black silk buttressed with Teflon felt strips is placed in this area (Fig. 1, A). The ends of this suture are passed through a plastic
Figure 1. A, Method of fixation of left ventricular cannula to maintain constant intraventricular position. B, Method of obtaining hemostasis after removing the cannula.
CLAMP
Figure 2. Diagrammatic representation of left heart-bypass apparatus.
RESERVOIR
PUMP
LEFT HEART BYPASS:
A
MODIFIED TECHNIQUE
1277
tourniquet. A stab wound is then placed within this mattress suture and a No. 40 Bardic catheter with a contained obturator is inserted into the left ventricular cavity through the stab wound. The obturator is then removed and the catheter clamped. The tourniquet is tightened, clamped and then fixed to the catheter with a heavy linen tie. This fixation prevents slippage of the cannula and maintains the fenestrated openings in a constant position. When appropriate connections are made for left heart bypass, flow is established and maintained constant by applying a screw clamp about the line leading from the left ventricle. Intraarterial pressure is monitored in both the upper and lower extremities and a balanced perfusion can be achieved by manipulation of the screw clamp. We have attempted to maintain a flow rate approximately 2/5 of estimated cardiac output for these bypasses. When this flow rate is achieved it is a simple matter to maintain a constant reservoir level by manipulation of the screw clamp (Fig. 2). At the termination of left heart bypass, the left ventricular cannula is removed and the mattress suture simply tied in its existing position. Additional sutures for hemostasis have rarely been necessary (Fig. 1, B). We have found this technique of left heart bypass to be extremely simple to accomplish, and one in which a very steady state perfusion is maintained.
REFERENCES 1. Cooley, D. A., DeBakey, M. E., and Morris, G. C.: Controlled extracorporeal circulation in surgical treatment of aortic aneurysm. Ann. Surg. 146:473, 1957.
2. DeBakey, M. E., Cooley, D. A., Crawford, E. W., and Morris, G. C.: Aneurysms of the thoracic aorta: Analysis of 179 patients treated by resection. J. Thor. Surg. 36:393, 1958.
The indications for the application of left heart bypass for lesions of the thoracic aorta have been well documented. 1• 2 During operations upon the thoracic aorta, maintenance of blood flow into the distal aorta is necessary to prevent spinal cord and renal ischemia. During repair of coarctation of the aorta, the aorta may be clamped since blood flow into the distal aorta is provided by the extensive collateral circulation which is characteristic of the disease entity. The technical considerations usually consist of cannulation of the left atrium by way of the left auricular appendage and replacement of the blood drained from it back into the femoral artery in a retrograde manner. In our experiences with this technique prior to 1962 we occasionally found it difficult to achieve a predictable steady state perfusion. In view of this, two primary objections to this approach became apparent. The left auricular appendage in the heart without atrial enlargement is a very delicate, thin-walled structure varying in size and shape from patient to patient. Although its cannulation can be easily effected on most occasions, tears of this thin fragile appendage are not uncommon and we have seen several instances in which significant bleeding has occurred. In addition, since the left atrial cavity is a low pressure area, negative pressures of any significant degree tend to cause collapse of the atrial walls about the drainage holes of an intra-atrial drainage catheter. Transient outflow obstruction (fluttering) of the draining catheter occurs and this tends to interfere with a steady state of flow. As a result, the machine operator is presented with the necessity to make constant corrections in flow rates in order to maintain blood balance and the danger of air embolism is increased. Such a perfusion is comSupported in part by National Institutes of Health Grant E5339-07 *Assistant Professor of Surgery, Jefferson Medical College, Philadelphia, Pennsylvania **Professor of Surgery, Jefferson Medical College; Attending Surgeon, Jefferson Medical College Hospital, Philadelphia, Pennsylvania
Surgical Clinics of North America- Vol. 47, No.5, October, 1967
1275
1276
LOUIS PIERUCCI, RUDOLPH C. CAMISHION
monly attended by variations of flow which result in pressure fluctuations above and below the points of aortic occlusion. In an effort to obviate this occasional problem, a technique of left ventricular cannulation is used. The pericardium is opened widely and an avascular portion of the apex of the left ventricle is selected for cannulation. A horizontal mattress suture of 0 black silk buttressed with Teflon felt strips is placed in this area (Fig. 1, A). The ends of this suture are passed through a plastic
Figure 1. A, Method of fixation of left ventricular cannula to maintain constant intraventricular position. B, Method of obtaining hemostasis after removing the cannula.
CLAMP
Figure 2. Diagrammatic representation of left heart-bypass apparatus.
RESERVOIR
PUMP
LEFT HEART BYPASS:
A
MODIFIED TECHNIQUE
1277
tourniquet. A stab wound is then placed within this mattress suture and a No. 40 Bardic catheter with a contained obturator is inserted into the left ventricular cavity through the stab wound. The obturator is then removed and the catheter clamped. The tourniquet is tightened, clamped and then fixed to the catheter with a heavy linen tie. This fixation prevents slippage of the cannula and maintains the fenestrated openings in a constant position. When appropriate connections are made for left heart bypass, flow is established and maintained constant by applying a screw clamp about the line leading from the left ventricle. Intraarterial pressure is monitored in both the upper and lower extremities and a balanced perfusion can be achieved by manipulation of the screw clamp. We have attempted to maintain a flow rate approximately 2/5 of estimated cardiac output for these bypasses. When this flow rate is achieved it is a simple matter to maintain a constant reservoir level by manipulation of the screw clamp (Fig. 2). At the termination of left heart bypass, the left ventricular cannula is removed and the mattress suture simply tied in its existing position. Additional sutures for hemostasis have rarely been necessary (Fig. 1, B). We have found this technique of left heart bypass to be extremely simple to accomplish, and one in which a very steady state perfusion is maintained.
REFERENCES 1. Cooley, D. A., DeBakey, M. E., and Morris, G. C.: Controlled extracorporeal circulation in surgical treatment of aortic aneurysm. Ann. Surg. 146:473, 1957.
2. DeBakey, M. E., Cooley, D. A., Crawford, E. W., and Morris, G. C.: Aneurysms of the thoracic aorta: Analysis of 179 patients treated by resection. J. Thor. Surg. 36:393, 1958.