Pulmonary artery balloon counterpulsation for right ventricular failure: II. Clinical experience

The use of pulmonary artery balloon counterpulsation (PABC) provided immediate salvage following cardiac surgical procedures in 2 patients with biventricular failure in whom inotropic drugs and intraaortic balloon counterpulsation did not provide sufficient support to allow weaning from cardiopulmonary bypass. Although both patients eventually died, the hemodynamic effectiveness of PABC was documented. The various clinical settings for right ventricular as well as biventricular failure are reviewed, the currently available options for treatment are summarized, and the directions for future laboratory investigation and possible clinical applications are presented.     

Surgical correction of pulmonary atresia with multiple large systemic-pulmonary collaterals.

A young patient in whom the pulmonary blood flow was supplied completely by five systemic-pulmonary collaterals underwent reconstruction of the pulmonary outflow tract by a new technique. This consisted of the insertion of a valve-bearing conduit between the right ventricle and an isolated segment of the descending aorta, which gave rise to three of the collaterals. Although the patient had a hypoplastic pulmonary artery confluence, other factors mitigated against its use as the sole conduit for right ventricular output.     

Phasic coronary flow: intraoperative evaluation of flow distribution, myocardial function, and reactive hyperemic response.

Using visual inspection of phasic flow patterns and understanding their physical determinants, intraoperative decisions regarding flow distribution, function of revascularized myocardium, and collateral communications can be made. Mean flow measurements cannot provide this information. Systolic compressive forces across most of the normally contracting left ventricle limit systolic myocardial perfusion. Consequently, normal flow through the left anterior descending, left circumflex, and dominant right coronary artery (supplying the inferior left ventricle) is predominantly diastolic (greater than 60%) and remains so during reactive hyperemia. Representative examples from 100 consecutive revascularizations are presented showing that when more than 40% of flow is systolic in the right coronary artery, high mean flows (greater than 100 ml/min) may go predominantly to the right rather than the left ventricle; in the case of the left coronary artery, high mean flow may supply myocardium undergoing infarction or replaced by scar rather than normally contracting muscle. When more than 60% of flow is diastolic without reactive hyperemia, borderline mean flow (40 to 60 ml/min) may indicate lack of distal ischemia rather than fixed distal resistance.     

Repair of Left Ventricular-Aortic Discontinuity Complicating Endocarditis from an Aortic Valve Prosthesis

A case of bacterial endocarditis from an aortic valve prosthesis is described in which subannular pseudoaneurysm caused discontinuity of the aorta and left ventricle. Successful repair was accomplished using compound sponge-felt to bolster the left ventricular outflow tract and to obliterate the aneurysm.     

Thrombolytic therapy for superior vena caval thrombosis following superior vena cava-pulmonary artery anastomosis

Immediate postoperative thrombosis of left superior vena cava-left pulmonary artery anastomosis in a modified Fontan procedure for single ventricle and pulmonary artery stenosis is described. Before thrombolytic therapy with streptokinase is initiated, confirmation of thrombosis by venography is mandatory to lessen the risk of cardiac tamponade or hemothorax. By this technique major surgical intervention is avoided, but close attention to the dose of streptokinase and the coagulation profile is essential. Measures to be taken if bleeding occurs with streptokinase therapy are described.     

Direct monitoring of arterial pressure in the newborn and infant: a difficult procedure made easy.

Accurate continuous measurement of arterial blood pressure, especially during and following operation, is indispensable for optimal management of the seriously ill newborn or infant. Conventional indirect techniques (flush technique, auscultation, Doppler monitoring device) for assessing the circulatory status in this age group are not reliable, and a direct method would be preferable. Arterial cannulation in such patients has been discouraged by the technical problems related to former techniques.     

The use of computed tomography to evaluate suspected mediastinal tumors.

Thirty patients with suspected mediastinal tumors were evaluated by computed tomography (CT) at UCLA Medical Center. Twenty patients with myasthenia gravis were examined for possible thymomas, benign and malignant; and 10 patients were studied for other mediastinal masses (including teratoma, seminoma, mediastinal lipomatosis, carcinoma, lymphoma, and paravertebral abscess). The CT scan was found useful in several respects: (1) yielding information not available by conventional radiographic techniques; (2) defining the anatomical location and extent of mediastinal tumors; (3) detecting pulmonary metastasis and involvement of mediastinal nodes in cases of malignancy; and (4) establishing the diagnosis of benign mediastinal fatty masses. On the basis of our early experience, we believe CT is a valuable adjunct in the preoperative assessment of patients with suspected mediastinal tumors.     

Myocardial protection during aortic valve replacement.

The results following aortic valve replacement (AVR) were compared in 40 patients in whom the myocardium was protected by topical hypothermic arrest or continuous coronary perfusion with sustained electrical fibrillation (Group A) and 40 similar patients in whom the hearts were also continuously perfused but were kept in the beating state (Group B). The operative mortality was not greatly different between the two groups, being 10 and 5%, respectively. The postperfusion cardiac performance was strikingly different, however. Seventeen patients (43%) in Group A required inotropic support, while this was necessary in only 1 patient (3%) in Group B. In this instance, recurrent ventricular fibrillation persisted despite attempts at reversion. These data show that the myocardium is preserved best during AVR when continuous coronary perfusion is used and the heart is maintained in the beating state.     

Effects of Conventional Hypothermic Ischemic Arrest and Pharmacological Arrest on Myocardial Supply/Demand Balance During Aortic Cross-Clamping

Aortic cross-clamping may produce ischemic damage due to a discrepancy between supply and demand. Supply is determined by noncoronary collateral flow and substrate stores, and demand by electromechanical activity, wall tension, and temperature. The effects of 60 minutes of conventional hypothermic ischemic arrest were compared to those of pharmacological arrest.Noncoronary collateral blood supply was comparable in both groups during cross-clamping. With ischemic arrest, mechanical activity and endocardial electrical activity persisted and wall tension fell progressively. With pharmacological arrest, electromechanical activity stopped in less than 1 minute but returned (with increased wall tension) nearly 1 hour. Thirty minutes following reperfusion, coronary flow was redistributed away from subendocardium after ischemic arrest and toward endocardium after pharmacological arrest. Myocardial performance was depressed severely after conventional arrest and only mildly after pharmacological arrest.We conclude that aortic cross-clamping is safer with pharmacological arrest than with ischemic arrest. The cardioplegic solution modifies the supply/demand balance favorably, but it is washed out by noncoronary collateral blood supply.     

Effects of Pulsatile Assistance and Nonpulsatile Flow on Subendocardial Perfusion During Cardiopulmonary Bypass

We compared the effects of pulsatile and nonpulsatile perfusion in 12 dogs on extracorporeal circulation. In beating empty and fibrillating hearts at 37° and 28°, coronary blood flow was measured by flowmeter and microspheres at diastolic pressures ranging between 50 and 130 mm Hg.At fixed systemic flow rates (range, 600 to 2,400 ml/min), pulsatile perfusion produced a transient (3 to 4 second) augmentation of diastolic pressure and then resulted in the following: (1) decreased peripheral vascular resistance (p < 0.05); (2) unchanged peak diastolic pressure (compared with nonpulsatile perfusion); (3) decreased mean aortic pressure (6 to 37%) (p < 0.05); (4) decreased coronary blood flow (10 to 45%) (p < 0.05); and (5) decreased subendocardial blood flow (from 512 to 438 ml/100 gm/min) (p < 0.05). Pulsatile perfusion in beating hearts (37° or 28°) did not reduce subendocardial vascular resistance, but did improve subendocardial perfusion by 27% and 36% in fibrillating hearts at 37° and 28°, respectively.We conclude that with the exception of ventricular fibrillation, pulsatile assistance offers no advantage over nonpulsatile perfusion and has the potential disadvantage of requiring higher pump flow rates to achieve any desired level of coronary and subendocardial flow.     

Double-outlet left ventricle

Origin of both great vessels from the left ventricle is an uncommon congenital cardiac anomaly. When there is an associated ventricular septal defect and pulmonary stenosis, the preoperative diagnosis has usually been that of tetralogy of Fallot. Operative repair was accomplished successfully in a 12-year-old boy with such a combination of defects. This involved patch closure of the ventricular septal defect, interruption of blood flow from the left ventricle to the pulmonary artery by suture closure of the pulmonary valve and annulus, and restoration of blood flow to the lung by using a Dacron tube conduit between the right ventricle and the distal main pulmonary artery. This represents the third successful operative repair of double-outlet left ventricle.     

Aortic Valve Replacement in the Young Child

Aortic valvotomy is a satisfactory procedure to relieve significant valvular stenosis in the young child in most instances. Intraoperative measurement to determine the reduction or elimination of a gradient across the valve confirms the adequacy of the orifice achieved by commissurotomy.This paper concerns itself with the occasional patient in whom a bicuspid valve is found for which little can be accomplished by operation because there is minimal or no commissural fusion. The valve orifice is adequate anatomically, but functionally it is severely obstructive. Recent experience with 2 children (aged 7 and 8 years) in whom aortic prosthetic valves were inserted after valvotomy suggests that in those rare circumstances in which life-threatening, severe obstruction cannot be relieved, valve replacement at the time of the initial operation may be appropriate.     

The use of internal and external vascular conduits for correction of D-transposition of the great arteries and double-outlet right ventricle with pulmonary atresia.

Between 1967 and 1978, an 11-year-old boy had undergone 3 separate systemic-pulmonary artery shunt operations. Two of the 3 shunt operations failed. The patient was restudied because of progressive cyanosis and was diagnosed as having D-transposition of the great arteries and double-outlet right ventricle with pulmonary atresia. Repair was successfully accomplished with the use of an internal vascular conduit and an external vascular conduit with a glutaraldehyde-treated porcine valve. Four months after the corrective procedure, the patient's exercise tolerance had improved dramatically.     

Ventricular Fibrillation: Its Effect on Myocardial Flow,Distribution, and Performance

Subendocardial ischemia develops in hearts that are fibrillated during cardiopulmonary bypass when: (1) the normal ventricle is fibrillated with a sustained electrical stimulus, (2) the hypertrophied ventricle is allowed to fibrillate spontaneously, (3) the fibrillating heart becomes distended, or (4) the perfusion pressure is reduced to approximately 50 mm Hg. Myocardial hypothermia reduces cardiac oxygen requirements during fibrillation but does not prevent ischemia when perfusion pressure falls to levels frequently attained during clinical open-heart operations. The ischemia occurs because flow cannot rise sufficiently to meet the metabolic demands of ventricular fibrillation. The forces interacting to impede adequate flow to the subendocardium during ventricular fibrillation are: (1) the compressive forces exerted on subendocardial muscle by the strength of fibrillation, (2) the compressive forces resulting from raised intracavitary pressure due to occlusion or malfunction of the ventricular vent, and (3) the evolution of myocardial edema as ischemia is prolonged.We have abandoned the use of ventricular fibrillation in clinical open-heart operations and now allow the heart to beat continually with adequate perfusion pressure. We have not needed to use inotropic drugs postoperatively after aortic or mitral valve replacement since adopting this technique.     

Surgical correction of complete atrioventricular canal

Operative mortality associated with complete atrioventricular canals has decreased from 75 pecent to as low as 10 per cent. The present report reviews the UCLA Hospital experience with the six children who underwent repair of this defect in the past two years. Emphasis is placed on preoperative assessment, operative technics, and postoperative management.     

Bilateral Subclavian Artery Aneurysm Associated with Idiopathic Cystic Medial Necrosis

Although cystic medial necrosis, either idiopathic or associated with Marian's syndrome, usually becomes manifest as an ascending aortic aneurysm, aortic insufficiency, aortic dissection, or a combination of these disorders, a rare case of bilateral subclavian artery aneurysm secondary to idiopathic cystic medial necrosis has occurred. Subclavian artery aneurysms most commonly represent poststenotic dilatation from anterior scalene or cervical rib compression, occasionally are associated with generalized arteriosclerotic peripheral vascular disease, and rarely are secondary to syphilitic or mycotic infections.Subclavian artery aneurysms have a major risk of rupture, embolus, or thrombosis, and therefore should be repaired. A reverse saphenous vein or prosthetic bypass graft from the carotid to the axillary artery provides adequate flow to the upper extremity. The aneurysm should be completely excised if possible, since reexpansion through small collaterals or through insufficient closure by ligation can occur and compress the brachial plexus after successful bypass. The clinical presentation, angiographic findings, and operative repair of a subclavian artery aneurysm secondary to cystic medial necrosis are described.     

Noncoronary collateral myocardial blood flow.

This study shows that noncoronary collateral flow occurs in normal hearts after chronic coronary occlusion and with left ventricular hypertrophy in variable amounts (0.2 to 16 ml/100 gm/min). Luminal--left ventricular flow is greatest when the heart is arrested by aortic cross-clamping, falls significantly when perfusion pressure is lowered to 50 mm Hg, and increases slightly when blood viscosity is reduced (hemodilution). Our findings indicate that the heart which is arrested by aortic cross-clamping may not be anoxic.     

Immunology and Lung Cancer

Carcinoma of the lung is the number one cancer killer in the United States. The overall cure rate is about 10%, and although resection is the best treatment available, five-year survival following operation is only 25%. Recent studies have shown that patients with lung cancer are immunosuppressed but that pulmonary tumors do contain tumor-associated antigens. Studies of other human tumors indicate that immunotherapy can augment tumor immunity and can be an effective surgical adjuvant.This communication reviews the basic principles of tumor immunology, with emphasis on the immunology of lung cancer, and discusses how these principles may be applied to the therapy of lung cancer.     

Improved technique for bedside insertion of the Swan-Ganz pulmonary artery catheter.

A method for inserting the Swan-Ganz pulmonary artery ballon has proved this to be a safe and efficient approach to hemodynamic monitoring of critically ill patients, frequently catheter utilizing direct subclavian venipuncture is presented. Our experience eliminating the need for bedside surgical procedures.     

Coronary artery bypass in hereditary factor XI deficiency

Hereditary factor XI deficiency is a disorder of coagulation that has been associated with postoperative bleeding. Because cardiopulmonary bypass itself induces transient abnormalities in hemostasis, the patient with factor XI deficiency could be at increased risk for bleeding after cardiac surgical procedures. We report the successful management of a 61-year-old man with hereditary factor XI deficiency who had coronary artery bypass. Treatment with low-dose aspirin, begun 24 hours postoperatively for graft patency, was well tolerated. Once recognized and aggressively treated, factor XI deficiency does not appear to be a contraindication to potentially life-saving procedures like coronary revascularization.