Inflow Occlusion for Semilunar Valve Stenosis

Transcription

1 Inflow Occlusion for Semilunar Valve Stenosis Robert M. Sade, M.D., Fred A. Crawford, M.D., and Arno R. Hohn, M.D ABSTRACT Twenty-nine patients have had valvotomy with inflow occlusion since 1975 at our institution: 7 for aortic stenosis and 22 for pulmonary stenosis. All patients with aortic stenosis and 11 with pulmonary stenosis were neonates. Six patients died, 3 with aortic stenosis and 3 with pulmonary stenosis. All of them were less than 2 days old. Two newborns with critical pulmonary stenosis required reoperation with an outflow patch at age 22 and 25 months. To determine morbidity and expense of inflow occlusion versus cardiopulmonary bypass for patients with pulmonary stenosis, we compared the 11 patients who were not infants and who had inflow OCclusion (age range, 3.5 to 26.8 years) with 10 patients who were operated on concurrently and who required bypass to correct associated minor intracardiac lesions (age range, 2.6 to 26.4 years). Significant differences (p < 0.01) were as follows (inflow occlusion versus bypass): operating room time, 2.0 f 0.4 versus 3.6 f 0.8 hours (mean f standard deviation); blood utilized, 0.3 f 0.5 versus 1.7 f 1.7 units; and total expense, $4,600 f 800 versus $7,000 f 1,600. Thus, inflow occlusion is safe in patients more than 2 days old, with early and late results similar to bypass, and is an attractive alternative for patients with isolated pulmonary valvular stenosis and for newborns with aortic stenosis. Valvotomy for stenosis of a semilunar valve is carried out with cardiopulmonary bypass in most centers. Though the safety and efficacy of the technique of inflow occlusion have been established over the past thirty years, this valuable procedure is not widely used and is in danger of being lost to future generations of cardiac surgeons because of its absence from training programs. We have used inflow occlusion for the treatment of some patients with From the Divisions of Cardiothoracic Surgery and Pediatric Cardiology, Medical University of South Carolina, 171 Ashley Ave, Charleston, SC Presented at the Twenty-eighth Annual Meeting of the Southern Thoracic Surgical Association, Palm Beach, FL, Nov 5-7, semilunar valve stenosis with good results. In order to ascertain its effectiveness, safety, and economy, we reviewed our experience with this procedure. Material and Method From October, 1975, to April, 1981, 29 patients underwent semilunar valvotomy with inflow occlusion at normothermia. Twenty-two patients had pulmonary stenosis (including ll newborns), and 7 had aortic stenosis. Inflow occlusion was used in patients with pulmonary stenosis when there was no evidence of associated intracardiac malformations requiring cardiopulmonary bypass, subpulmonary muscular stenosis, dysplastic pulmonary valve, or right ventricular peak systolic pressure higher than left ventricular pressure. For patients with aortic stenosis, inflow occlusion was used only in newborns with critical aortic stenosis without associated intracardiac lesions requiring repair. The patients with pulmonary stenosis ranged in age from 14 hours to 26.8 years (4.3 f 6.5 years, mean k standard deviation), and those with aortic stenosis ranged from 1 day to 3 months old (0.5 f 1.1 months). Except for patent ductus arteriosus in the newborns, there were no important associated lesions in the group with pulmonary stenosis. One patient with aortic stenosis had a large ventricular septal defect, and another had severely obstructive coarctation of the aorta. Operative Technique Through a sternotomy, tapes with rubber tourniquets are placed around both venae cavae, and a site for incision is selected on the anterior pulmonary artery, usually in the region of poststenotic dilatation (Fig 1A). A straight vascular clamp partially occludes the anterior pulmonary artery, the vessel is incised for a distance suitable for adequate exposure, and four stay sutures are placed at the apices of the incision and at the midpoint of its two sides by The Society of Thoracic Surgeons

2 571 Sade, Crawford, and Hohn: Inflow Occlusion for Semilunar Valve Stenosis A B C Fig 1. Operative technique: (A) Tapes with rubber tourniquets are placed around both uenae cavae, and a site for incision is selected (broken line). (B) A straight vascular clamp allows incision of the pulmonary artery. (c) Inflow occlusion permits accurate valuotomy. (See text for details.) (Fig 1B). The caval tourniquets are snugged, the heart is allowed to empty itself with a few beats, the clamp is removed, and the blood is suctioned from the pulmonary artery. The surgeon and assistant each pick up adjacent leaflets in succession until all commissures are exposed and incised (Fig 1C). Stay sutures are elevated by the surgeon and assistants, the tourniquets are released, and as the pulmonary artery fills, the partial occlusion clamp is reapplied. While the vessel is closed with standard suture technique, the anesthesiologist intravenously administers sodium bicarbonate, 1 mg per kilogram of body weight, 50% dextrose, 1 mgikg, and calcium gluconate (lo%), 10 mgikg. The wound is closed in the standard manner. If the ductus arteriosus is patent, a cross-clamp is placed through the transverse sinus to occlude the aorta and main pulmonary artery immediately before the pulmonary artery is opened. For patients with aortic stenosis, the same technique is followed except that a distal crossclamp is routinely used, and the valvotomy is done by inserting a mosquito clamp through the aortic valve orifice and dilating the valve by opening the clamp in two or three directions.

3 572 The Annals of Thoracic Surgery Vol 33 No 6 June 1982 Comparative Groups To compare the morbidity and expense of treating older children with pulmonary stenosis by either inflow occlusion or cardiopulmonary bypass, we examined the records of all patients with pulmonary stenosis operated on during the Sam% time period with cardiopulmonary bypass for repair of associated minor intracardiac lesions or because of systemic right ventricular pressure. Patients requiring a pulmonary outflow patch were excluded. We found 10 patients satisfying these criteria to compare with the 11 patients more than 1 year old who underwent pulmonary valvotomy with inflow occlusion. We compared the time in the operating room from start of anesthesia to arrival in the intensive care unit, the number of blood transfusions administered, postoperative morbidity and mortality, temperature for the first five postoperative days, and total cost of hospitalization, including hospital bill and physicians fees (surgeon, anesthesiologist, consultants). Comparisons were made by one-way analysis of variance. Results Six patients died, 3 with pulmonary stenosis and 3 with aortic stenosis. All those who died were less than 2 days old. The newborns with pulmonary stenosis died of pneumonia with sepsis (2) and biventricular necrosis. Two babies with aortic stenosis and endocardial fibroelastosis, 1 of whom also had severe coarctation of the aorta, died. The other patient with aortic stenosis who died had a large ventricular septa1 defect and an obstructive subaortic mass of primitive endocardial cushion tissue on the anterior leaflet of the mitral valve which was not recognized until postmortem examination. A female infant with a patent ductus arteriosus underwent pulmonary valvotomy at the age of 3 weeks. Severe congestive heart failure developed and banding of the ductus arteriosus was done [ll on the tenth postoperative day. When she was 1 year old, increasing cyanosis developed. Cardiac catheterization demonstrated a closed ductus arteriosus and a right ventricle-pulmonary artery pressure gradient of 60 mm Hg. A pericardial patch was placed across the pulmonary annulus when the patient was 25 months old. She has done well since. Another female neonate underwent pulmonary valvotomy at the age of 14 hours; later, increasing cyanosis developed. Cardiac catheterization demonstrated a gradient of 66 mm Hg from right ventricle to pulmonary artery. A pericardial outflow patch was placed across the pulmonary annulus when she was 22 months old. All other patients have remained asymptomatic. One underwent cardiac catheterization and was found to have a right ventricle-pulmonary artery pressure gradient of 10 mm Hg. By physical examination, 1 patient has trivial pulmonary insufficiency, another has mild insufficiency, and the rest have no diastolic murmur. All patients who survived aortic valvotomy have remained asymptomatic. In 1 patient cardiac catheterization two years after operation demonstrated a pressure difference between left ventricle and descending aorta of 22 mm Hg; mild aortic insufficiency was present also. No other patient has clinical evidence of aortic insufficiency. The comparative groups of patients undergoing pulmonary valvotomy with inflow occlusion versus cardiopulmonary bypass were similar in number and age (Table). The age of the group having inflow occlusion ranged from 3.5 to 26.8 years, while that of the bypass group ranged from 2.6 to 26.4 years. During the operation, the group undergoing cardiopulmonary bypass spent more time in the operating room and used more blood than the group undergoing inflow occlusion. The average time of inflow occlusion was 1.5 k 0.3 minutes, and average bypass time was 33.7 f 20.6 minutes. The peak daily temperature (Fig 2) and length of hospitalization after operation were not different for the two groups. No patient in either group died, and the complications were similar: 2 patients in each group had postpericardiotomy syndrome and 1 patient undergoing bypass had right hemiparesis that cleared in two days. The hospital bill, physicians fees, and the sum of these two were significantly greater in the group undergoing cardiopulmonary bypass, the total being more than 50% greater in this group than in the patients having inflow occlusion.

4 573 Sade, Crawford, and Hohn: Inflow Occlusion for Semilunar Valve Stenosis Inflow Occlusion versus Cardiopulmonary Bypussa Variable Age Total time in OR (hours) Blood units Peak daily temperature postop ( C) Time of discharge postop (days) Hospital bill (1,000$) Physicians fees (1,000$) Total expense (1,000$) Cardiopulmonary Inflow Occlusion (n = 11) Bypass (n = 10) P Value 8.2 f f f k k f f k 0.8 All values are expressed as mean t standard deviation. NS = not significant; OR = operating room. 9.9 f * * f f f f k 1.6 NS NS NS co I I ;5! P Inflow occlusion 0 Cardiopulmonary bypass I I I I I I Postoperative Day Fig 2. Comparison of peak temperature from day of operation to fifth postoperative day. There were no significant differences between the two groups. Comment Aortic valvotomy can be performed very safely in most children with aortic stenosis [2]. Mortality, however, has been reported to be quite high in newborns with aortic stenosis. In the Toronto series, for example, all patients had cardiopulmonary bypass, and 68% of babies less than 1 month of age died [2]. Similarly, our mortality in newborns with aortic stenosis was 43%, with all 3 deaths in infants less than 2 days of age; these are the sickest children with the most severe obstruction. Inflow occlusion has been previously reported for the treatment of aortic stenosis. At Boston Children s Hospital, 18 of 20 infants undergoing this procedure left the hospital alive [3]. As in our series, no deaths were related to the technique of inflow occlusion. The valve tissue in newborns with aortic stenosis is P I P s! primitive [4]. It is often difficult to define the location of commissures. Therefore, there is little advantage in the additional time provided by cardiopulmonary bypass to do a careful valvotomy. We do not incise commissures, but place a hemostat through the orifice and vigorously dilate the valve by opening the clamp in two or three directions. The validity of this technique is fortified by the report of Trinkle and his colleagues [5], who used a closed technique of valvotomy for aortic stenosis, inserting a dilator through the annulus by way of the left ventricular apex. Though they did not visualize the valve, merely dilated the orifice, their early hemodynamic results have been excellent. Our patient who was recatheterized two years after operation had a pressure gradient of only 22 mm Hg, and all the other survivors are doing well clinically. Pulmonary valvotomy has been performed for uncomplicated pulmonary stenosis since Varco [6] introduced the technique more than thirty years ago. Its safety and efficacy were indicated in the report by Mistrot and his colleagues [7] from the University of Minnesota. They did pulmonary valvotomy with inflow occlusion in 110 patients ranging from 2 days to 36 years old. Sixty-nine postoperative cardiac catheterizations demonstrated a decline in peak systolic pressure gradient from right ventricle to pulmonary artery from 93 mm Hg to 23 mm Hg. Four patients (3.6%) died, 2 of whom were only a few days old. Four patients required reoperation for residual gradients. The overall results

5 574 The Annals of Thoracic Surgery Vol 33 No 6 June 1982 were excellent or good in 78% of the patients, fair in 15%, and poor in 7%. The groups with fair and poor results consisted mainly of patients with dysplastic pulmonary valve, now considered to be a contraindication to valvotomy with inflow occlusion. Our series had similar clinical results: death occurred in 3 newborns, all less than 2 days of age, and reoperation for residual stenosis was required in 2 newborns, 1 of whom was 14 hours old at the time of operation. In our group of patients the time of occlusion never exceeded 2 minutes, and averaged 1.5 minutes; the valvotomy was unhurried and done with good visualization of the anatomy of the valve. Two of our patients had trivial or mild pulmonary insufficiency. The rest had none. Thus, based on our experience and that of the University of Minnesota [7], pulmonary valvotomy under inflow occlusion seems safe and efficacious. We also have shown that inflow occlusion is more economical than cardiopulmonary bypass. Although the comparative groups were not randomized and many in the bypass group required intracardiac procedures in addition to pulmonary valvotomy, all operations were simple and straightforward, allowing, we believe, a valid comparison of the variables measured. Inflow occlusion requires less total operating room time, and is a smaller burden on the blood bank than cardiopulmonary bypass. We recognize that hospital charges and physicians fees are only approximate reflections of actual costs. We believe, however, that there are few hidden costs for the inflow occlusion technique. For example, we do not require the presence of a pump technician or pump standby during the procedure, and use no special instruments or supplies beyond an ordinary sternotomy set. It is likely that the actual costs of inflow occlusion, like the hospital and physician charges, are significantly lower than those of cardiopulmonary bypass. The economy of inflow occlusion in terms of limited hospital resources and monetary costs are not adequate reasons to use the procedure. We agree with Loewy [8] that cost-effectiveness should be a factor only in deciding between equally efficacious alternative forms of therapy. We believe that we and others have shown that inflow occlusion and cardiopulmonary bypass are, in fact, equally effective in treating semilunar valve stenosis in the patients described. An additional benefit of using inflow occlusion is in the training of residents. This technique is valuable not only for the treatment of semilunar valve stenosis, but in other situations, such as temporary decompression of the heart for repair of traumatic wounds and creation of atrial septa1 defect. It is a technique that is in danger of being lost to new generations of cardiac surgical trainees who have never seen it done, and are therefore unlikely to think of using it in the occasional situation when it could be lifesaving. There are few lesions that can be treated equally well by either an open or a closed procedure. This series of patients provided us with an unusual opportunity to isolate the effect of cardiopulmonary bypass on postoperative course. The observation that there was no difference in peak daily temperature when essentially the same operation was done with or without the use of bypass dispelled our previously held, but mistaken, belief that cardiopulmonary bypass itself is associated with fever postoperatively. We believe the use of inflow occlusion should be limited to newborns with aortic stenosis without important associated intracardiac lesions and to patients with valvular pulmonary stenosis without dysplasia of the valve, associated intracardiac lesions requiring repair, suprasystemic right ventricular pressure, or subpulmonary obstruction. In patients selected by these criteria, inflow occlusion is safe and reliable, providing excellent surgical exposure of the valve with ample time for valvotomy, as well as producing economies in blood usage, operating room time, and monetary expense. It also adds training in a useful technique to the education of surgical residents. We believe our experience and that of others justify continued use of inflow occlusion for the patients we have defined. We are grateful to David Bartles, M.S., and C. Boyd Loadholt, Ph.D., Department of Biometry, Medical University of South Carolina, for performing the statistical analyses.

6 575 Sade, Crawford, and Hohn: Inflow Occlusion for Semilunar Valve Stenosis References 1. Earle GF, Sade RM, Riopel DA: Banding of patent ductus arteriosus for palliation of cyanotic congenital heart disease. Presented to the Southeastern Pediatric Cardiology Society, Asheville, NC, Sept 20, Sandor GGS, Olley PM, Trusler GA, et al: Longterm follow-up of patients after valvotomy for congenital valvular aortic stenosis in children: a clinical and actuarial follow-up. J Thorac Cardiovasc Surg 80:171, Bernhard WF, Keane JF, Fellows KE, et al: Progress and problems in the surgical management of congenital aortic stenosis. J Thorac Cardiovasc Surg 66:404, Sade RM, Castaneda AR: Congenital lesions of the mitral and aortic valves. In Hardy JD (ed): Textbook of Surgery: Principles and Practice. Philadelphia, Lippincott, 1977, pp Trinkle JK, Grover FL, Arom KV: Closed aortic valvotomy in infants: late results. J Thorac Cardiovasc Surg 76:198, Varco RL: Discussion of Muller WH, Longmire WP: The surgical treatment of cardiac valvular stenosis. Surgery 30:41, Mistrot J, Neal W, Lyons G, et al: Pulmonary valvotomy under inflow stasis for isolated pulmonary stenosis. Ann Thorac Surg 21:30, Loewy EH: Cost should not be a factor in medical care. N Engl J Med 302:697, 1980