Pulmonary autograft replacement of the aortic valve in the potential parent

Aortic root replacement in adolescents and young adults: composite graft versus homograft or autograft

BACKGROUND

Aortic root replacement (ARR) is a technically demanding procedure that can be performed using a variety of prosthetic devices. Root replacement in the young, but grown-up, patient poses unique problems in terms of the long-term outcome and active lifestyle that must be guaranteed by this operation. To identify the "ideal" substitute for ARR in the young, clinical results in teenagers and young adults (<35 years) operated on in the past two decades were reviewed.

METHODS

Thirty-eight patients younger than 35 years underwent ARR between January 1980 and December 1996. Eighteen patients, aged 30+/-5 years, had ARR with composite graft (group 1), whereas 20 patients, aged 28+/-6 years, had ARR with aortic homografts or pulmonary autografts (group 2). Primary indication for the operation was aortic insufficiency with anuloaortic ectasia (12 of 18) in group 1 and aortic insufficiency with or without anuloaortic ectasia (16 of 20) in group 2. Urgent ARR was required in 3 (17%) group 1 patients and 1 (5%) group 2 patient (p = 0.01).

RESULTS

Operative deaths were 2 (11%) in group 1, caused by hemorrhage and low output, and none in group 2. There were 4 (25%) late deaths in group 1, caused by embolism (2), hemorrhage, and myocardial infarction, and 1 (5%) in group 2, caused by arrhythmia. Survival was 81% +/- 9%, and 55%+/-18% at 2 and 10 years in group 1 versus 94%+/-5% at 2 years in group 2 (p = 0.04). Freedom from valve-related events was 93%+/-6% and 62%+/-18% at 2 and 10 years in group 1 versus 100% at 2 years in group 2 (p = 0.02). Freedom from reoperation in group 1 was 75% +/- 22% at 10 years, whereas no reoperations were done in group 2. Seven (58%) group 1 patients versus 1 (5%) group 2 patient were on cardiac medications (p = 0.001), and 11 (92%) group 1 patients versus no group 2 patients were on warfarin therapy at follow-up. All survivors were back to school or prior employment.

CONCLUSIONS

Survival early after ARR does not differ depending on the type of prosthesis. Valve-related events are common, and reoperation may be needed late after ARR with composite grafts. Despite limited follow-up with biologic devices, the prevalence of complications with composite grafts makes homograft or autograft ARR preferable in adolescents and young adults.

The Ross procedure: shorter hospital stay, decreased morbidity, and cost effective

BACKGROUND

The Ross procedure has become an accepted and sometimes preferred alternative to mechanical aortic valve replacement. One criticism of the Ross procedure is that it may have a higher operative mortality, morbidity, and cost. Several groups have shown that this operation can be performed safely with less than 3% mortality. The issue of higher cost has not been resolved. In this retrospective study we compared a consecutive group of patients undergoing the Ross procedure with an age- and disease-matched group of patients who underwent mechanical aortic valve replacement.

METHODS

From 1993 to 1996, 22 consecutive adult patients (age range, 20 to 57 years; mean, 38 +/- 14 years) underwent the Ross procedure. Twenty-seven patients (age range, 17 to 57 years; mean, 41 +/- 10 years) underwent mechanical aortic valve replacement between 1991 and 1996. The hospital cost (in 1996 dollars) and postoperative length of stay were calculated for each patient using Transition I, a hospital-wide cost accounting system.

RESULTS

There was no hospital mortality in either group. The incidence of significant valve-related complication was 5% (1/22 patients) in the Ross procedure group and 22% (6/27 patients) in the mechanical valve group. There were two late deaths in the group with mechanical aortic valve replacement. The length of stay for the Ross procedure group was 5.9 +/- 2.1 days, versus 8 +/- 1.85 days for the mechanical valve group (p < 0.01). The mean hospital costs were not significantly different, $23,140 +/- $7,825 for the mechanical valve group and $23,226 +/- $6,960 for the group having the Ross procedure.

CONCLUSIONS

The data from this review demonstrate that the Ross procedure can be done safely, with short hospital stays, decreased morbidity, and costs comparable with those of standard mechanical aortic valve replacement in patients with isolated aortic valve disease.

Pulmonary autograft procedure for aortic valve disease: long-term results of the pioneer series

BACKGROUND

Pulmonary autograft replacement of the diseased aortic valve has not been widely practiced due to concerns regarding late autograft competence and the consequences of creating pulmonary valve disease. To investigate this, the fate of the pioneering series of patients has been determined.

METHODS AND RESULTS

The 131 hospital survivors of the pulmonary autograft operation at the National Heart Hospital from 1967 to 1984 were identified and their outcomes determined to 1994. Age at operation was 11 to 52 years, and 109 patients were male. Autograft implantation was orthotopic subcoronary (107), free-standing root (20), or Dacron mounted (2). In 113 patients, homografts replaced the native pulmonary valve. Ten and 20 years after operation, survival was 85% and 61%, freedom from autograft replacement was 88% and 75%, and freedom from replacement of pulmonary position homografts was 89% and 80%, respectively. Causes of deaths (53) included chronic heart failure (13), complications of reoperation (12), and endocarditis (7). Autograft regurgitation, the most common indication for reoperation, appeared primarily technical in nature, usually due to cusp prolapse. Degeneration was found in only 3 of 30 explanted autografts, and the young patients showed no increase in late valve failure. Homografts outperformed other valve replacements in the pulmonary position, but patients with orthotopic subcoronary and root autografts survived similarly.

CONCLUSIONS

The pulmonary autograft offers low rates of degeneration, endocarditis, and thromboembolism for a period lasting >20 years, particularly in the young, with reoperation mainly required for malpositioning of the autograft cusps. The capacity of the autograft to maintain viability with minimal degeneration is not matched by any other biological valve replacement.

Pulmonary autograft implantation in the dilated aortic annulus

The application of the pulmonary autograft (Ross) procedure in the treatment of dilated aortic annulus is still controversial, because technical errors of implantation are more likely to occur as the host annular diameter increases. The Ross procedure was successfully employed in a 28-year-old woman with a dilated aortic annulus after simple annular plication. The annulus was plicated beneath the three commissures where the pulmonary autograft was subsequently attached. The diameter of the annulus was reduced from 32 to 26 mm. This technique may provide a number of advantages compared with aortic valve replacement, especially for women of child-bearing age.

Geometric mismatch of the aortic and pulmonary roots causes aortic insufficiency after the Ross procedure

BACKGROUND

Geometric mismatch between the two semilunar valves can cause aortic insufficiency after the Ross procedure. Thus, whenever the aortic root is larger than the pulmonary root, surgical reduction of the aortic anulus or of the sinotubular junction (or both) to match the diameters of the pulmonary root is necessary to prevent late malfunction of the pulmonary autograft.

METHODS

The Ross procedure was performed in 81 patients during the past 5 years. The diameters of the aortic and pulmonary roots were measured in 77 patients. Reduction of the aortic anulus and of the sinotubular junction was necessary in 27 patients, reduction of the aortic anulus alone in 12, and reduction of the sinotubular junction alone in 10. The pulmonary autograft was implanted in the subcoronary position in the aortic root in two patients, as a complete root replacement in 58, and as an inclusion root in 21.

RESULTS

There was one operative death, caused by myocardial infarction. Aortic insufficiency developed in one patient who did not have measurement and reduction of the aortic anulus, and aortic root replacement was necessary 2 weeks later. Patients have been followed up from 2 to 64 months (mean 15 months). Two patients have required late reoperations: one because of pulmonary artery stenosis and the other because of a false aneurysm between the autograft and the mitral valve. The most recent Doppler echocardiographic study shows that 90% of the patients have only trace or no aortic insufficiency, and 10% have mild aortic insufficiency.

CONCLUSION

This experience suggests that adjustment of the diameter of the aortic anulus or of the sinotubular junction of the aorta may be important to prevent aortic insufficiency after the Ross procedure.

Should the freehand allograft be abandoned as a reliable alternative for aortic valve replacement?

Cryopreserved aortic allografts were used for aortic valve replacement in 80 patients between 1986 and 1994 (infracoronary in 46 and complete root replacement in 34). Hospital mortality was 6.3% (5/80) with all deaths occurring in the infracoronary group. Three of five deaths were in patients with endocarditis and valve ring abscess. Left ventricular-aortic mean pressure gradients across the allograft valves were significantly lower for root replacement patients (mean, 9.0 +/- 6.9 mm Hg versus 18.1 +/- 8.7 mm Hg for infracoronary patients) (p = 0.0001). No patient having root allograft replacement had early echocardiographic aortic insufficiency greater than grade 1 versus 28% of those having infracoronary implantations. Late aortic insufficiency of grade 2 or greater was seen in 46% of patients having infracoronary implantation versus 17% of patients having root implantation. Nine patients had explantation of an aortic allograft (eight infracoronary and one root). Reasons for explantation were as follows: endocarditis (three infracoronary, one root), technical (three infracoronary), undiagnosed idiopathic hypertrophic subaortic stenosis (1 patient), and prolapsing infracoronary leaflet (1 patient). Actuarial freedom from grade 3 and 4 aortic insufficiency or explantation was 77% at 7 years for infracoronary implantations. We conclude that the infracoronary aortic allograft has an unacceptable frequency of late insufficiency and its use in this position should be abandoned. The substantial incidence of late endocarditis in the infracoronary (free-hand) aortic allograft was surprising.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary autograft in children: realized growth potential

Pulmonary autograft replacement of the aortic valve has the potential to remain viable and grow in proportion to the somatic growth of the child. Changes in aortic annulus and sinotubular dimensions were compared early and late postoperatively, and related to normal. Eighty-six children, 0.9 to 21 years, were operated on between 1986 and 1993: 42 had a root replacement, 24 an inclusion cylinder, and 20 a scalloped subcoronary implant. Actuarial survival at 7 years was 96.5% +/- 2.0%. Freedom from reoperation for the pulmonary autograft or the homograft reconstruction of the right ventricular outflow tract was 92% +/- 4%. Freedom from reoperation on the autograft in root replacements was 96% +/- 4%, in the inclusion cylinder was 100%, and in the scalloped subcoronary was 90% +/- 7% (not significant). Aortic annulus and sinotubular junction diameters were compared with normal values predicted by body surface area. In 22 intraaortic implants, early and late postoperative annulus diameter mean Z values are in the normal range. In the 23 root replacements, early annulus diameter was within the normal range, but late Z values were larger than normal (p < 0.02). Intraaortic implant annulus diameter increased proportionally to somatic growth, but the sinotubular junction, which was small, remained small but increased toward normal. In the root replacements, the annulus increased in diameter and became dilated. The sinotubular junction, which was small early, increased and was within the normal range late. Lower operative risk and valve durability without failure suggest improved results with inclusion cylinder technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Ventricular function after the arterial switch operation for transposition of the great arteries

The theoretical advantages of anatomical repair have resulted in the widespread use of the arterial switch operation for transposition of the great arteries. However, preservation of systemic ventricular performance and late functional results have not been well documented. To evaluate late postoperative ventricular function, we reviewed 53 consecutive patients undergoing arterial switch operation for transposition of the great arteries with or without a ventricular septal defect over the 8-year period from March 1985 to 1993. Forty-two patients had simple transposition of the great arteries and 11 patients had associated ventricular septal defects that were closed at operation. Mean age at operation was 1.8 months (range, 1 day to 36 months), and mean patient weight was 3.8 kg (range, 1.8 to 15.6 kg). All but 8 patients were neonates. There were six operative deaths (11.3%, 6/53) and two late deaths during a median follow-up of 23 months (range, 0.1 to 99.5 months). Actuarial survival at 8 years was 83% +/- 6%. Left ventricular outflow tract obstruction has not been identified, and 9 patients (20%, 9/45) have right ventricular outflow tract gradients exceeding 20 mm Hg, 3 of whom have required reoperation. Eighteen patients have mild neo-aortic valve regurgitation. All survivors are currently in New York Heart Association class I, and are in sinus rhythm. Systolic left ventricular function is well preserved with ejection fractions greater than 0.60 in all survivors followed up for more than 4 months (41 patients). Left ventricular end-diastolic volume index is elevated in only 1 patient, a patient who had pulmonary artery banding as a neonate.(ABSTRACT TRUNCATED AT 250 WORDS)