The bidirectional cavopulmonary shunt.

The bidirectional cavopulmonary shunt improves systemic arterial oxygen saturation without increasing ventricular work or pulmonary vascular resistance. Since 1983, 17 patients have undergone a cavopulmonary shunt procedure (five primary operations, 12 secondary operations). Diagnoses were single ventricle complex (n = 4), hypoplastic right heart syndrome (n = 10), and hypoplastic left ventricle (n = 3). Age at primary operation ranged from 3 1/2 to 30 months (median 6 months). Weight ranged from 3.5 to 9.7 kg. Age at secondary operation ranged from 10 months to 14 years (median 15 months). Seven cavopulmonary shunt operations were performed without cardiopulmonary bypass (six via thoracotomy and one via sternotomy) and 10, with cardiopulmonary bypass. All patients in the bypass group had additional procedures: takedown of modified Blalock-Taussig shunt, seven patients; revision of right ventricular outflow tract, four patients; reconstruction of pulmonary arteries, four patients; tricuspid valvuloplasty, one patient; and Damus procedure, one patient. There was one (1/17) operative death (Damus procedure). One patient required early revision. Follow-up ranges from 1 to 53 months (median 23 months). Twelve of 16 had a good to excellent late result, with a rise in mean arterial oxygen saturation from 69% to 83%. Three patients died late (4 to 53 months) (pulmonary vascular disease, pulmonary arteriovenous malformations, and pneumonia, one patient each). There was one late failure (converted to Glenn shunt). The cavopulmonary shunt is an excellent palliative procedure when right atrium-pulmonary artery connection (modified Fontan) must be deferred because of age, weight, or anatomic considerations. Five patients have undergone right atrium-pulmonary artery connection later. In addition, at the time of the modified Fontan operation, the cavopulmonary shunt approach may optimize the anatomic connection (eight additional patients).

Late reoperation for systemic atrioventricular valve regurgitation after repair of congenital heart defects.

Since 1979, 17 infants and children have undergone reoperation for systemic atrioventricular (AV) valve regurgitation 6 weeks to 7 years after repair of congenital heart defects. Prior operations were repair of incomplete or complete AV canal (14 patients), Mustard repair of complex transposition of the great arteries including ventricular septal defect closure (2 patients), or first-stage operation for hypoplastic left heart (1 patient). Age ranged from 6 months to 11 years. In 12 of the 17 patients (10, AV canal; 1, transposition; 1, hypoplastic left heart), valve reconstruction was possible. Operative techniques included a combination of septal cleft approximation, leaflet resection, commissural annuloplasty, or ring annuloplasty. There were no operative deaths, and there were no reoperations in the repair group. The condition of these patients has improved. Follow-up ranges from 1 month to 9 years (mean follow-up, 4.1 years). Five of the 17 patients (4, AV canal; 1, transposition) underwent valve replacement. There were no operative deaths. Follow-up ranges from 3 to 8 years. Three patients later underwent re-replacement of the prosthetic valve; there was 1 late death. The condition of all 4 survivors is improved. Substantial AV valve regurgitation can occur months or years after repair of congenital heart defects. A combination of reconstructive techniques may be useful in preserving native valve function and avoiding systemic AV valve replacement.

Balloon dilatation of stenotic right ventricle-to-pulmonary artery conduits.

In seven children with obstructed right ventricle-to-pulmonary artery conduits, balloon dilatation (BD) was performed 10-58 months after insertion of the conduit. Average valve gradient was reduced from 69 to 32 mmHg. Obstruction at the conduit-branch pulmonary artery connection became apparent after dilatation of the valve; these distal stenoses also were dilated. It is concluded that the useful lifetime of a right ventricle (RV) to pulmonary artery (PA) conduit may be extended by BD of an obstructed biological valve and/or BD of a stenotic conduit-pulmonary artery anastomosis.

Experience with Damus procedure.

Sixteen patients with complex cyanotic congenital heart disease underwent an operation involving the use of the aorta and the main pulmonary artery as the egress for systemic arterial blood flow (the Damus-Kaye-Stansell operation, modified as discussed). The indication for this approach was either preoperative aortic outlet obstruction or likelihood that the repair would produce such obstruction. A modification of the original technique is introduced that involves transection of both great arteries, anastomosis of the contiguous aortic and pulmonic walls, and connection of the distal aorta to the perimeter of the new (bivalved) great artery. Eleven of the 16 patients survived operation: six of six who underwent a concurrent Fontan operation, four of six who underwent a concurrent right-ventricle-to-pulmonary-artery-conduit procedure, and one of four who underwent a concurrent systemic-pulmonary shunt procedure. Postoperative status in the 11 survivors is good: one patient has a gradient from the left ventricle to the aorta, 10 of 11 have little or no aortic regurgitation, and the remaining patients have a normal physiological status. We conclude that the Damus procedure is a useful addition to the surgical armamentarium for treatment of certain types of cyanotic congenital heart disease.

The cryopreserved homograft valve in the pulmonary position: early results and technical considerations.

Since September, 1985, 20 patients have undergone implantation of a homograft valve in the pulmonary position (16 pulmonary, 4 aortic). There were 11 primary operations and 9 reoperations. In 7 of 11 primary operations the homograft valve was utilized as a composite conduit with a short Dacron extension. In four of five reoperations for a failed porcine valved conduit, a composite homograft conduit was used. Four patients underwent implantation of a free homograft in a previously repaired right ventricular outflow tract (RVOT). Age ranged from 15 days to 22 years. There was one operative death (5%), a seven-week-old infant with truncus arteriosus. Long-term follow-up ranges from 1 to 30 months. Clinical performance has been satisfactory in 18 of 19 patients. One patient undergoing free implantation of a pulmonary valve in the RVOT required replacement at 18 months with a porcine valve. In this patient, pulmonary insufficiency was caused by distortion of the annulus secondary to dilatation and pulmonary hypertension. Nine of 18 survivors do not require medication. Eleven of 18 have trivial to mild pulmonary insufficiency murmurs without symptomatology. The homograft valve is extremely useful in reconstruction of the right heart, however, early insufficiency murmurs have been noted. Distortion of the valve annulus may contribute to the early onset of a benign insufficiency murmur. Residual distal obstruction or pulmonary hypertension may be a contraindication to the use of a free homograft in the orthotopic position.

Long-term follow-up of viable frozen aortic homografts. A viable homograft valve bank.

There is currently a renewed interest in the use of both fresh and commercially available frozen homograft valves for children and young adults. This has prompted us to review a series of 32 patients who received frozen homograft valves for aortic replacement between 1973 and 1975. The cryogenic technique evolved to include the use of selected antibiotics and equilibrated dimethyl sulfoxide solution to freeze homografts at a rate of 1 degrees C per minute to liquid nitrogen temperatures of -196 degrees C. Histologic sections of experimental frozen valves explanted 6 months postoperatively revealed the presence of viable donor cells, and tissue culture demonstrated the reproductive capacity of cusp fibroblasts. Of the 32 frozen viable homografts implanted in this series, 23 were inserted as free-sewn aortic replacements and nine were premounted on stents before implantation in the aortic position. There were two operative deaths, and three valves failed as a result of the technical problems of mounting in one patient and surgical insertion of a free graft in two patients. Of the 22 patients who remained at long-term risk, 13% with free-sewn grafts and 57% with premounted valves underwent reoperation for valve failure. After 10 years of follow-up, 15 (68%) of these patients, 12 (80%) with free-sewn and three (43%) with premounted valves, are alive with their original valve in place. Actuarial analysis shows that 58% of the 32 valves implanted are functional at the beginning of the eleventh year. There have been six late deaths resulting in an overall actuarial patient survival rate of 79% at 10 years and 69% after 13 years. These clinical results are believed to add support to our current application of the frozen homograft in selected patients.

Evaluation of the effects of systemic nitroglycerin on perfusion of ischemic myocardium in coronary heart disease assessed intraoperatively by antegrade blood flow through intact saphenous vein bypass grafts.

To evaluate systemic nitroglycerin (NTG) effects on reduced perfusion of ischemic myocardium in coronary disease, intravenous NTG actions on coronary circulatory dynamics were directly assessed intraoperatively during aortocoronary bypass surgery in 24 patients. Thus metered antegrade blood flow was measured through 56 separate intack saphenous vein bypass grafts to analyze NTG perfusion response in the obstructed native coronary artery (CA). In 34 bypassed CA with proximal luminal diameter narrowing greater than 50% to 90%, NTG reduced (p less than 0.01) graft flow (GF) 82 to 63 cc/min, thereby indicating that NTG dilated proximal stenoses with resultant increased CA flow. In 11 bypassed CA obstructed greater than 90% to 100% with well developed collaterals distally, NTG decreased (p less than 0.05) GF 64 to 53 cc/min, thus indicating enhanced collateral flow. In contrast, in 11 bypassed CA obstructions greater than 90% to 100% without collaterals, that NTG increased (p less than 0.02) GF 91 to 100 cc/min indicated NTG nonresponsiveness of the severely diseased CA. Thus systemic NTG improves perfusion to ischemic myocardium subserved by diseased coronaries with less than 90% stenosis or by greater than 90% obstructed vessels with substantial collaterals distally.

Spontaneous heterograft aortic valve failure.

Glutaraldehyde-treated porcine aortic valve prostheses have been in clinical use for ten years. The long-term durability of these valves remains unknown although they have functioned well in most large clinical series for more than five years. At the present time, several manufacturers produce bioprostheses mounted on flexible stents. This report concerns the failure of an Edwards porcine xenograft in the aortic position 15 months following implantation. At reoperation, the right and left coronary leaflets of the explanted valve were torn from the aortic wall. The loss of wall integrity suggests that during the process of mounting the xenograft on the flexible stent, the aortic walls of the bioprosthesis may have been thinned beyond a critical point of maintenance of wall strength. The pathological and clinical findings of similar cases are reviewed.

Heterograft cardiac valve prostheses: a five-year follow-up.

The major advance in the management of valvular heart disease over the past twenty years has been due to prosthetic valve operation. The bioprostheses have good hemodynamic function and a low rate of thromboembolism although the long-term durability is unknown. In this series of 25 patients with 27 valves implanted over five years, there was an 9% early mortality and a 12% late mortality. There have been no thromboembolic episodes. Primary valvular dysfunction requiring operation occurred in 7.4% (2 out of 27). All surviving patients are in New York Heart Association Functional Class I or II.

Surgical treatment of post-myocardial infarction ventricular septal defects.

Ventricular septal defect (VSD) following myocardial infarction has long been recognized as a lethal complication of severe coronary artery disease. Between 1969 and 1978, 13 patients underwent operative repair of post-myocardial infarction VSDs associated with large left-to-right shunts and markedly impaired left ventricular performance. Emergency cardiac catheterization in 12, coronary cineangiography in 11, and operative repair in 13 were performed 1 to 15 days after ventricular septal perforation. The surgical approach consisted of left ventricular aneurysmectomy or infarctectomy with VSD repair and with coronary revascularization when indicated. Survival could not be predicted on the basis of preoperative hemodynamics, extent of coronary artery disease, age, time from the appearance of the VSD or myocardial infarction to definitive surgical therapy, or preoperative functional class. There were six survivors, all of whom had anterior septal defects. All but one of the nonsurvivors had posterior VSDs. The one patient who died with anterior VSD had the highest left-to-right shunt--2.6 L/min/m2. Emergency operative repair of acute post-myocardial infarction VSD is warranted in this high-risk group of patients who otherwise have little chance of survival.

Cardial myxomas: a clinical diagnostic challenge.

Our experience consists of seven intracardiac myxomas in five patients seen over an 8 year period. It includes one patient who had three primary tumors, each anatomically distinct, occurring at 4 year intervals. The initial clinical presentation included embolic phenomena, unexplained neurologic symptoms, hemodynamic obstruction, and vague systemic illness. Preoperative diagnosis was confirmed by echocardiography or angiocardiography in all cases. At operation, only two of seven tumors were found to arise from the vicinity of the fossa ovalis; the other five arose from the atrial wall or ventricular septum. Wide resection of the tumors constituted the key to successful treatment. All patients have done well for periods of follow-up ranging from 6 months to 8 years. Awareness of cardiac myxoma is the key to diagnosis; treatment should be uniformly successful in all instances once the proper diagnosis has been made. Although recurrences are rare, all patients must be followed up closely for the development of new tumors, and a thorough investigation of all chambers must be conducted in patients with suspected recurrence.

Incremental intravenous nitroglycerin for control of afterload during anesthesia in patients undergoing myocardial revascularization.

In 25 patients undergoing coronary artery bypass grafting hemodynamic measurements (including values obtained with Swan-Ganz catheterization in 21 of the patients) were made before and after administering a bolus injection of 64 or 96 mcg of nitroglycerin to relieve intraoperative hypertension. This pharmacological agent reduced afterload and preload without raising heart rate. The effect was apparent within 1-3 min and lasted 5-10 min. Untoward hypotension was not encountered in any instance. This intervention appears to be a safe approach to the treatment of intraoperative hypertension in patients with coronary artery disease.

Hemodynamic assessment of the new aortic Carpentier-Edwards bioprosthesis.

Although glutaraldehyde-preserved porcine aortic Hancock heterografts have lower thromboembolism incidence than mechanical aortic valves, Hancock xenografts provide less functional aortic outflow orifices and thereby greater transvalvular gradients than mechanical prostheses. The newly developed aortic Carpentier-Edwards porcine heterografts comprise a thin-walled Elgiloy flexible metal stent covered with Teflon which provides somewhat wider internal orifices than aortic Hancock valves of the same external annulus diameter. Since aortic Carpentier-Edwards xenografts have not been clinically evaluated previously, the present study assessed cardiac function and heterograft performance (1.7 months postoperation) and clinical status (4.2 months postoperation) of 19 patients with severe aortic stenosis and/or regurgitation prior to surgery. Left ventricular end-diastolic pressures decreased (17 to 9 mm Hg), cardiac index remained normal, and clinical symptomatology diminished markedly. Mean peak transxenograft systolic pressure was only 16 mm Hg (valve area 1.73 cm2), without meaningful regurgitation. Thus aortic Carpentier-Edwards bioprostheses provide generally excellent heterograft function which appears more favorable than previous reports of Hancock xenografts.

Hemodynamic assessment of the glutaraldehyde-preserved porcine heterograft in the aortic and mitral positions.

Although glutaraldehyde-preserved porcine heterograft (PH) valves may have a lowered incidence of thromboembolism compared to mechanical valves, data concerning postoperative function in PH valves are incomplete. Accordingly, 26 patients receiving PH in the aortic (AO) or mitral position (MIT) were studied at cardiac postoperative catheterization (mean 19 weeks). The 12 AO patients had an average peak systolic gradient of 19 mm Hg (range 3-52 mm Hg); mean valve area (VA) 1.33 cm2 (0.75-2.5; two patients had postoperative aortic insufficiency. The 14 MIT patients had a mean gradient of 7.9 mm Hg (0-13.1); VA 1.84 cm2 (0.70-3.2; postoperative mitral regurgitation occurred in two patients. AO stent diameter (SD) related to VA, r = 0.85; and peak gradient, r = -0.75. However, MIT SD did not relate to VA or peak gradient. At the 14-month follow-up examination 9 of 11 AO and 7 of 11 MIT patients improved by at least one functional class. Thus, with the advantage of reduced thromboembolism and generally satisfactory valve hemodynamics, further clinical trial of glutaraldehyde-preserved porcine heterografts is justified.