Practice guidelines in cardiothoracic surgery.
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Biomedical subjects
Publications and source records attributed to G G Lindesmith.
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The Society of Thoracic Surgeons remains greatly concerned about the use of raw mortality data as the sole measure to determine quality of care following coronary artery bypass surgery. Use of such data without consideration of risk factors that are predictors of hospital mortality and of other indices of quality of care is inappropriate and misleading and may adversely affect the care of the high-risk cardiac surgical patient. The Society is committed to the principle of providing the public with accurate information regarding the conduct of coronary artery surgery. However, it believes that the data provided by HCFA do not provide this information and should not be used as the sole index of quality of care following coronary artery bypass surgery.
The cardiac catheterization data and angiograms of 30 infants with pulmonary atresia and intact ventricular septum were reviewed to evaluate the growth potential of the right ventricle after transventricular pulmonary valvotomy. An index of right ventricular size based upon the tricuspid valve anulus, right ventricular inlet, and right ventricular outlet dimensions was used. Fourteen infants (Group I) were treated with systemic-pulmonary arterial shunts only, whereas 16 infants (Group II) underwent pulmonary valvotomy and 14 had shunting as well. Follow-up studies demonstrated the lack of right ventricular growth in Group I (right ventricular index of 7.0 +/- 3.2 preoperatively versus 7.0 +/- 2.0 postoperatively) and persistence of severe right ventricular hypertension (systolic pressure of 121 +/- 31 versus 120 +/- 48 mm Hg). In contrast, the right ventricular cavity increased in nine of 11 Group II infants who underwent valvotomy. Right ventricular index increased from 7.7 +/- 1.6 to 11.0 +/- 3.1 (p less than 0.01) and systolic pressure fell from 132 +/- 31 to 83 +/- 50 mm Hg (p less than 0.1). Early and late mortality in Group I was 50% (7/14), whereas only three of 16 Group II infants died (p greater than 0.1). It is concluded that pulmonary valvotomy should be attempted in all neonates with pulmonary atresia and intact ventricular septum in whom an outflow tract is identified angiographically to maximize the potential for right ventricular growth and increase its functional contribution to normal circulation.
The initial surgical approach to the infant with pulmonary atresia and intact ventricular (PA-IVS) is to establish an adequate source of pulmonary blood flow and, when possible, relieve right ventricular (RV) outflow obstruction. The selection of patients for pulmonary valvotomy, alone or in combination with a systemic-pulmonary arterial shunt, depends on the presence of an RV outflow tract and the adequacy of the RV chamber. To evaluate the size of the RV cavity in PA-IVS, an RV index (RVI) was developed using biplane angiographic measurements of the sum of the tricuspid valve annulus and the RV inflow and the RV outflow tracts. The RVI was normalized by relating it to the aortic diameter (Ao) at the diaphragm (RVI/Ao). The RVI/Ao was 13.5 +/- 1.4 in 20 control subjects and only 7.3 +/- 2.6 in 26 PA-IVS patients (p less than 0.001), and was within the normal range in only two of the 26. Since 1976, pulmonary valvotomy plus a Blalock-Taussig shunt has been performed in 10 infants, with one death. Serial cardiac catheterizations in five of nine survivors demonstrated substantial RV growth in all, with the RVI/Ao increasing from an average of 8.0 to 12.5. In contrast, patients who underwent a shunt alone had no change in RV cavity size. We conclude that pulmonary valvotomy may be performed successfully in most PA-IVS patients, but usually must be combined with a systemic-pulmonary shunt. In a small minority of patients, a normal RV cavity, as evidenced by an RVI/Ao greater than or equal to 11, appears to be sufficient to sustain adequate pulmonary blood flow after valvotomy alone. The RVI/Ao ratio is a simple method of quantitatively evaluating RV cavity size and is helpful in planning the initial surgical approach for these infants.
A modified Fontan operation was performed on nine patients, ages 8--24 years (mean 14 years), with tricuspid atresia. The right atrium and right ventricle were connected with a valved conduit in five patients and directly in four. A porcine inferior vena caval valve was used in two patients. Prior operations had been performed in eight patients. There were no surgical deaths. Complications included pleural effusions, low-output syndrome, renal failure and atrioventricular block. There were two late deaths, only one of which was of cardiac origin. One patients required reoperation because of residual atrial septal defect at 1 month and again at 56 months for conduit stenosis. One patient required a pacemaker. Follow-up extends 6--65 months (mean 34 months). Survivors are clinically well and active, although four are taking medications. Postoperative cardiac catheterizations were done in six patients. Right atrial pressures were elevated in each, with no gradients across the conduit or pulmonary valve except in the one patient with conduit obstruction. Three patients had small residual ventricular septal defects and one a residual Blalock anastomosis. The Fontan procedure is an effective operation for tricuspid atresia. It may be further modified by establishing direct continuity between right atrium and right ventricle without a valve conduit in patients with a functioning pulmonary valve. The long-term ability of the right atrium to maintain adequate pulmonary flow and the effects of chronically elevated right atrial pressure on hepatic function and the cardiac conduction system must still be examined.
A simple method is described to correct saphenous vein bypass grafts that inadvertently have been made too long or too short or have become twisted. The essential feature of the technique is the use of a Satinsky vascular clamp to hold the divided ends of the vein and maintain their alignment during the repair. The most accessible portion of the vein is used as the site for the repair, leaving the aortic and coronary artery ends of the graft intact. While we have not had need to use the technique frequently, we have found it to be a simple method and believe it to be useful when such instances arise.
The effectiveness of cooling the subendocardial myocardium by five different methods was evaluated in a group of 100 patients. The most effective and consistent method to cool the heart was by total body hypothermia with the heat exchanger in the cardiopulmonary bypass system. Myocardial temperature became equal to vena caval blood temperature after only a one minute lag. The least effective methods of myocardial cooling were those in which a bath of chilled fluid enveloped the outside surface of the heart, with and without aortic cross-clamping. The drop in ventricular septal temperature was so small that topical hypothermia, by itself, may be worthless. Two methods in wich chilled fluid was perfused through the coronary system produced a significant lowering of myocardial temperature. One of these methods employs coronary perfusion with a cold cardioplegic solution in addition to total body hypothermia. It is our current choice for myocardial protection during cross-clamping of the ascending aorta.
Myocardial revascularization has been carried out by us in 67 patients 70 years of age or older. Advanced coronary artery disease was found at angiography in more than two thirds of the patients. The postoperative morbidity and mortality compare very favorably with those in younger patients. The early and late mortality in the 67 patients was 4.5 percent and 6.0 percent, respectively. Fifty-seven survivors have been followed an average of 21 months; for most patients there has been a pronounced improvement in clinical classification. Properly selected, patients of advanced age can undergo successful revascularization surgical procedures. The adequacy of function of the left ventricle, proper timing of the surgical operation and an aggressive yet realistic approach seem to be major determinants for a good result.
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Over a 10-year period, 123 patients with transposition of the great vessels underwent the Mustard procedure. The hospital mortality for the series was 10.6%. There were seven late deaths, five of which were presumable due to arrhythmia. Sinus rhythm was noted postoperatively in 53% of the patients. Almost all the survivors had achieved catch-up growth when evaluated 6 months to 10 years later. A growth spurt was more consistently seen in the patients who were operated on under 2 years of age. Physical endurance and school performance were on a par with their normal peers or better in about half of the survivors. Severe neurologic problems were present in five patients. Postoperative catheterizations in 42 patients showed a rather high incidence of residual interatrial shunts, mild left ventricular outflow obstruction, and mild superior vena caval obstruction. Pulmonary venous obstruction and serious tricuspid regurgitation were not encountered.
To facilitate the insertion of prosthetic valves, holders are available which keep the poppet out of the area of suture insertion or keep the open ends of the struts occluded. No such holders are available for use during insertion of xenograft valves, and it seems unlikely that one could be used, for danger of damage to the valve leaflets. To obviate this problem, we have brought the flexible struts together with a suture at the time of insertion. The struts assume their original open position upon cutting the suture.
An alternative approach for correction of supracardiac (type I) total anomalous pulmonary venous return is described. A median sternotomy is used. The posterior wall of the left atrium and the common pulmonary venous trunk are exposed through the transverse sinus. A direct anastomosis between these structures, ligation of the systemic-venous connection (vertical vein), and closure of the interatrial septal defect results in a one-stage repair. In our experience with the supracardiac anomaly in 20 patients, we have found that this approach consistently affords better exposure than other techniques currently in use for surgical correction of this anomaly.
A follow-up study of 1532 patients who had coronary artery bypass grafts from 1969 through 1974 revealed that the 5-year survival rate was substantially better than that recorded in previously published series of patients with similar disease demonstrated angiographically who did not undergo operation. Within this group of operated patients, those who had complete myocardial revascularization (i.e., three grafts for those with three-vessel disease) experienced a significantly better long-term prognosis than those who had fewer grafts than the number of vessels obstructed. The mortality curve in the completely revascularized patients was very similar to that of the general population of the United States, corrected to correspond to this patient sample in age and sex.
Fifty coronary reoperations were performed in 49 patients. The reasons for the operations were occluded or stenotic grafts in 23 patients, an inadequate first operation in 13, progression of coronary atherosclerosis in 3, and combinations of these reasons in 11. Mediastinal adhesions made the operations difficult and produced hazards. Six patients died from the operation. Seven surgical mishaps occurred, including damage to five functioning grafts from the previous operation and laceration of two ventricles. Nine patients had less than complete operations because angiographically demonstrated targets could not be found. Repeat angiography was performed on 9 of the surviving patients. Ten of the 14 new or revised grafts were found to be functioning. Although a repeat operation is more difficult technically and carries additional risks as compared with a first operation, the indications are thought to be the same for both first and secondary revascularization procedures. The increased risks of the repeat operations are compelling arguments to strive for complete revascularization at an initial operation in order to avoid the necessity of the second one.
Permanent pacemaker therapy in children with complete heart block is necessary occasionally. Ten patients ranging in age from 8 months to 15 years were treated with an implanted P-wave, synchronous epicardial pacemaker. Indications for implantation were persisting postsurgical heart block, congestive failure, syncopal attacks, and arrhythmias. There were two deaths not attributed to pacemaker malfunction. The remaining eight children have been followed up for 38 to 108 months. There have been 27 pulse generator replacements. Twenty-three were for battery exhaustion, three for electromechanical failure, and one was due to arrhythmia. Rhythm disturbances have occurred on eight occasions. There have been no infections. It is concluded that the implanted P-wave synchronous pacemaker is an effective method of therapy when indicated for children with complete heart block.
Ten patients in whom palliative Mustard operations have been performed for transposition of the great vessels with ventricular septal defect and elevated pulmonary vascular resistance are reported. There has been early or late mortality in this group of patients, and postoperative morbidity has been minimal. Five of them have been recatheterized, and the results indicate substantial improvement in postoperative arterial oxygen saturation with change in pulmonary vascular resistance. The operation is reserved for those patients in whom peripheral desaturation is the major cause of symptomatology. Clinical improvement has been gratifying, and the continued use of the operation in selected patients seen indicated.