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J Thorac Cardiovasc Surg 1994;107:1373-1374
© 1994 Mosby, Inc.
LETTERS TO THE EDITOR |
Cardiac Surgery Departmenta
To the Editor:
The combination of atrial septal defect (ASD) and coronary artery disease is rare.
1 Surgical treatment of this double ailment at first analysis seems to pose only a few problems. However, we report here a case of simultaneous treatment of both lesions, complicated by a serious postoperative myocardial deficiency. This deficiency was reversible by double mechanical circulatory assistance, intraaortic balloon pumping (IABP), and femorofemoral assistance by means of a heparin-coated circuit.
A 60-year-old female patient was admitted to the Cardiac Surgery Department of Mulhouse General Hospital for an aorta-coronary bypass and correction of an ASD. Preoperative echography showed, on the one hand, a slight anomaly of left ventricular diastolic function and, on the other hand, paradoxical septal movement commonplace with an ASD.
Left ventricular systolic function was evaluated by ventriculography and found normal. A double, tight stenosis on the middle and proximal left anterior descending artery was not amenable to angioplasty. The ASD was of the ostium secundum type, with moderate pulmonary artery hypertension (40/17 mm Hg, 25 mm Hg) and an output ratio of 3. Pulmonary venous flow was within normal limits.
The operation was performed under the usual conditions. Overall clamping time of the aorta was 90 minutes. Left anterior descending artery bypass was effected with a left internal mammary artery graft in situ. The ASD was closed with a 3 cm diameter Dacron polyester fiber patch.
Cardioplegic treatment was applied by way of a right atriotomy through the coronary sinus. It was repeated after 30 minutes. Hypothermia was moderate at 31° C, corrected by conventional progressive warming. Weaning from extracorporeal circulation (ECC) was difficult. Severe pulmonary artery hypertension occurred with systolic pressure of 70 mm Hg. Despite assistance through renewed ECC during 1 hour, 50 minutes, myocardial deficiency did not allow weaning from ECC. Femorofemoral assistance was therefore set up, in which all elements were preheparinized (Carmeda system, Bio-Medicus pumphead; Bio-Medicus, Inc., Eden Prairie, Minn.). The arterial cannula was inserted through the right femoral artery up to the iliac level, and the venous cannula was threaded through the right femoral vein up to the right atrium by means of the right scarpa surgical approach. This treatment involved IABP through the left femoral artery. Hemodynamics were restored with an assisted output of 3 L/min (mean arterial pressure, 85 mm Hg; mean pulmonary arterial pressure, 15 mm Hg, central venous pressure, 15 mm Hg and heart rate, 85 beats/min) and stabilized. Pulse output existed only because of the action of the IABP; the arterial pressure curve was flat when pumping was stopped. Counterpulsion was tuned to the R peak of the electrocardiogram. Pressures in the pulmonary artery were flat, identical to those of the central venous system, with or without the IABP.
During the first 6 postoperative hours, the main problem lay in maintaining blood volume, which was endangered both by bleeding at the thoracic and mediastinal drainage points (400 ml/hr) and by an abundant diuresis (300 ml/hr). Assisted output could progressively reach 4 L/min, principally because of the intravenous administration of trinitrine (2 mg/hr). The whole assistance process was effected with heparinization, with coagulation tests conducted to match 1.5 times the control sample 8 hours after such assistance. Femorofemoral assistance ensured stable hemodynamics with a mean pressure of 85 mm Hg; IABP tuned to the R peak of the electrocardiogram ensured a pulse output. Pulmonary pressures were linear, without any cyclic modification, and identical to the central venous pressure.
Eight hours after such assistance was implemented, an independent systolic wave unrelated to the IABP appeared on the arterial pressure curve, thus proving the emergence of an autonomous pulse. This provided hope for recovery of left ventricular contractile function. Later, the patient's condition improved gradually. Assistance cannulas were withdrawn on the twentieth hour; IABP was withdrawn on the next day. On day 14, the ejection fraction of the left ventricle (isotopic) was 45%. The patient left the service on day 18.
Failure of the left ventricle after operation to repair an ASD has previously been reported. 2 In some reports, 1, 3, 4 failure was caused by combined disorders, unseen or overlooked (arterial hypertension, coronary insufficiency). In our case, the patient did not have hypertension, and ischemic disease had long been known and even had been surgically treated. Others 5 have suggested the existence of a relative hypoplasia of the left ventricle, 5 with dilatation of the right ventricle. The mean diameter of blood vessels supplying the left ventricle could cause a relative myocardial ischemia. 5 Further, modifications of hemodynamics consecutive to the paradoxic movement of the interventricular septum 5, 6 could also be involved. Booth and coworkers 2 insist on the notion of left ventricular filling problems, to be carefully checked before operation on patients previously treated for ASD.
With our patient, no clear cause could be found to explain this catastrophic biventricular myocardial deficiency on cessation of IABP. However, Doppler echocardiography performed before the operation revealed the existence of a left ventricular filling problem. The originality of this observation resides in the association of femorofemoral assistance and IABP to ensure both satisfactory hemodynamics and a blood flow such as would protect coronary perfusion and reduce the afterload. Femorofemoral assistance made up for 80% of the patient's total volume for 20 hours.
The technical particularity of this case lies in our use of a new type of preheparinized assistance material. Indeed, the complete circuitry, oxygenator included, was coated with a thin layer of a new polymer, Carmeda polymer. This made it possible to reduce overall heparinization by two thirds. Troubles brought by blood hemostasis are one of the major causes of morbidity and mortality in long-term circulatory assistance. The slight dose of heparin required in this case leads to the hope for a reduction in this type of complication. Other results with this type of material are similarly encouraging. The strategy used in this case, its relative simplicity of implementation, and its ease in monitoring are encouragements to choose this technique in the treatment of major postcardiotomy myocardial malfunctions.
References
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