Aortic root replacement with human tissue valves in aortic valve endocarditis

Lanthanum carbonate, a phosphate binder, inhibits calcification of implanted aortic allografts in a rat model

OBJECTIVES

Calcification is one of the major postoperative problems after aortic allograft implantation. We hypothesized that phosphate binders, lanthanum carbonate and calcium carbonate inhibit calcification of implanted aortic allografts and verified this hypothesis using a rat model.

METHODS

Aortas were harvested from 4-week-old Brown Norway rats and implanted into the subdermal space of 4-week-old Lewis rats. Twenty-seven recipient Lewis rats were divided into Group N, Group L, and Group C (9 rats per group), which were fed a normal diet, a normal diet containing 3% lanthanum carbonate, and a normal diet containing 3% calcium carbonate, respectively. Implanted aortic allografts were explanted 2 weeks later. Calcification of aortic allografts was evaluated using von Kossa staining and calcium content assay. Calcification score was defined in von Kossa staining as 0 (none), 1 (mild), 2 (moderate), and 3 (severe). Serum calcium and phosphorus levels at euthanasia were measured.

RESULTS

Calcification scores were 2.6, 1.2, and 0.8, and calcium content was 48.9, 15.8, and 8.9 mg/dry·g, in Groups N, L, and C, respectively. Calcification was significantly reduced in Groups L and C. Serum calcium level was 11.5, 12.2, and 13.5 mg/dl, and serum phosphorus level was 15.4, 12.5, and 11.7 mg/dl, in Groups N, L, and C, respectively. Serum calcium level in Group C was significantly higher than in the other two groups.

CONCLUSIONS

Lanthanum carbonate and calcium carbonate significantly reduced calcification of implanted aortic allografts in young rats. Although calcium carbonate induced hypercalcemia, lanthanum carbonate has significant potential to inhibit calcification of implanted aortic allografts.

Surgical treatment of aortic valve endocarditis: a 26-year experience

Objective

We have retrospectively analyzed the results of the operations made for aortic valve endocarditis in a single center in 26 years.

Methods

From June 1985 to January 2011, 174 patients were operated for aortic valve endocarditis. One hundred and thirty-eight (79.3%) patients were male and the mean age was 39.3±14.4 (9-77) years. Twenty-seven (15.5%) patients had prosthetic valve endocarditis. The mean duration of follow-up was 7.3±4.2 years (0.1-18.2) adding up to a total of 1030.8 patient/years.

Results

Two hundred and eighty-two procedures were performed. The most frequently performed procedure was aortic valve replacement with mechanical prosthesis (81.6%). In-hospital mortality occurred in 27 (15.5%) cases. Postoperatively, 25 (14.4%) patients had low cardiac output and 17 (9.8%) heart block. The actuarial survival rates for 10 and 15 years were 74.6±3.7% and 61.1±10.3%, respectively. In-hospital mortality was found to be associated with female gender, emergency operation, postoperative renal failure and low cardiac output. The long term mortality was significantly associated with mitral valve involvement. Male gender was found to be a significant risk factor for recurrence in the follow-up.

Conclusion

Surgery for aortic valve endocarditis has significant mortality. Emergency operation, female gender, postoperative renal failure and low cardiac output are significant risk factors. Risk for recurrence and need for reoperation is low.

Immediate and long-term results of valve replacement for native and prosthetic valve endocarditis

BACKGROUND

The objective of the present study was to compare current results of prosthetic valve replacement following acute infective native valve endocarditis (NVE) with that of prosthetic valve endocarditis (PVE). Prosthetic valve replacement is often necessary for acute infective endocarditis. Although valve repair and homografts have been associated with excellent outcome, homograft availability and the importance of valvular destruction often dictate prosthetic valve replacement in patients with acute bacterial endocarditis.

METHODS

A retrospective analysis of the experience with prosthetic valve replacement following acute NVE and PVE between 1988 and 1998 was performed at the Montreal Heart Institute.

RESULTS

Seventy-seven patients (57 men and 20 women, mean age 48 +/- 16 years) with acute infective endocarditis underwent valve replacement. Fifty patients had NVE and 27 had PVE. Four patients (8%) with NVE died within 30 days of operation and there were no hospital deaths in patients with PVE. Survival at 1, 5, and 7 years averaged 80% +/- 6%, 76% +/- 6%, and 76% +/- 6% for NVE and 70% +/- 9%, 59% +/- 10%, and 55% +/- 10% for PVE, respectively (p = 0.15). Reoperation-free survival at 1, 5, and 7 years averaged 80% +/- 6%, 76% +/- 6%, and 76% +/- 6% for NVE and 45% +/- 10%, 40% +/- 10%, and 36% +/- 9% for PVE (p = 0.003). Five-year survival for NVE averaged 75% +/- 9% following aortic valve replacement and 79% +/- 9% following mitral valve replacement. Five-year survival for PVE averaged 66% +/- 12% following aortic valve replacement and 43% +/- 19% following mitral valve replacement (p = 0.75). Nine patients underwent reoperation during follow-up: indications were prosthesis infection in 4 patients (3 mitral, 1 aortic), dehiscence of mitral prosthesis in 3, and dehiscence of aortic prosthesis in 2.

CONCLUSIONS

Prosthetic valve replacement for NVE resulted in good long-term patient survival with a minimal risk of reoperation compared with patients who underwent valve replacement for PVE. In patients with PVE, those who needed reoperation had recurrent endocarditis or noninfectious periprosthetic dehiscence.

Twenty-four year experience with reoperations after ascending aortic or aortic root replacement

OBJECTIVE

A retrospective analysis of early and late outcome for late (>4 weeks) reoperations on the ascending aorta or aortic root.

MATERIALS AND METHODS

During a 24-year interval, starting in 1974, 834 patients underwent replacement of the ascending aorta (39.2%) or aortic root (60.8%). During the same period, 56 patients with a mean age of 51.1 +/- 14.4 years underwent reoperation after ascending aortic or aortic root replacement. Predominant indications for reoperation were false aneurysm in 25 (44.6%) patients and true aneurysm in 18 (32.1%) patients. Most frequent surgical procedures were redo aortic root replacement in 30 (53.6%) patients and closure of a false aneurysm in 14 (25.0%) patients. Median interval between the operations was 51 months. Eighteen (32.2%) patients underwent concomitant partial or total aortic arch replacement.

RESULTS

Hospital mortality was 5.4% (n = 3; 70% CL: 2.4-8.4%). Cause of death was low cardiac output in two patients and rupture of the aorta at the distal suture line in one patient. Univariate analysis identified two or more previous operations (P = 0.038) and the interval between initial operation and reoperation for complication of less than 8 months (P = 0.005) as risk factors for hospital death. Multivariate analysis indicated operation for active endocarditis or vascular graft infection as an independent risk factor for hospital death (P = 0.038, odds 14.6). Follow-up was complete, median 3.1 years. Nine (16.9%; 70% CL: 11.7-22.1%) patients died during that period. Estimated survival at 1, 5 and 10 years was 91.2, 84.0 and 76.4%. One patient underwent another reoperation. Estimated event-free survival at 1, 5 and 10 year is 84.3, 72.2 and 65.6%.

CONCLUSION

False aneurysm formation and progression of aneurysmatic disease are the predominant causes for late reoperations after aortic root or ascending aortic replacement. Reoperations can be performed with low hospital mortality and good late results.

Reoperations on the ascending aorta and aortic root: pitfalls and results in 134 patients

BACKGROUND

This analysis was performed to evaluate the results of reoperations on the ascending aorta and aortic root.

METHODS

All reoperations (n = 134) on the aortic root and ascending aorta performed between February 1981 and April 1998 were retrospectively analyzed. Indications for reintervention were a true or false aneurysm (35%), acute dissection (3.0%), aortic valve stenosis and/or insufficiency (23.1%), prosthetic valve endocarditis (32.8%), and combinations (4.5%). The principal reoperations performed were aortic root replacement (composite graft, freestyle, aortic allograft, or pulmonary autograft) in 116 patients, ascending aortic replacement in 10 patients, and closure of a false aneurysm in 5 patients. Results were analyzed using univariate statistical methods.

RESULTS

Hospital mortality was 6.6% (8 patients). Univariate predictors of hospital death were preoperative functional class III or IV (p = 0.02), an interval of less than 6 months between the primary and actual operation (p = 0.02), preoperative creatinine level of more than 200 micromol/L (p = 0.001), acute aortic dissection (p = 0.001), intraoperative technical problems (p = 0.001), and postoperative dialysis (p = 0.001). Freedom from repetitive reoperation was 99% at 1 year and 98% at 5 and 10 years.

CONCLUSIONS

Reoperations on the aortic root and ascending aorta can be performed with an early mortality which is very acceptable.

Aortic root replacement with the pulmonary autograft: an invariably competent aortic valve?

BACKGROUND

Pulmonary autograft aortic root replacement was used in adults. Risk factors for aortic regurgitation (AR), and for pulmonary allograft valve stenosis are identified.

METHODS

From February 1991 through April 1998, 80 adults (mean age 34.4 years) underwent pulmonary autograft aortic root replacement. Primary diagnosis was AR in 43 (53.7%) patients, aortic stenosis in 13 (16.3%) and mixed disease in 24 (30%) patients. A root reinforcement ring was used in 32 (40%) patients.

RESULTS

There was no hospital mortality. Estimated patient survival is 100% at 7 years. A total of 3 patients underwent reoperation: 2 on the autograft for severe AR, 1 for pulmonary allograft stenosis. Freedom from reoperation on the autograft is 96.7 +/- 2.4% at 7 years. Multivariate analysis indicated bicuspid aortic valve disease as an incremental risk factor for AR at discharge (p = 0.036, odds 3.5). Univariate analysis identified operation for pure AR as risk factor for AR during follow-up (p = 0.041). Mild AR or more increased from 2.5% at discharge to 11.3% during follow-up (p = 0.008). Progression of AR was limited by the use of a reinforcement root ring (p = 0.031). Freedom from mild AR or more in patients with and without a reinforcement root ring was 100% and 72.9 +/- 9.3% respectively, at 5 years (p = 0.119). Pulmonary allograft stenosis occurred in 15 (22.5%) patients. Multivariate analysis revealed that large sized pulmonary allografts were less prone to stenosis (p = 0.048, odds 0.13).

CONCLUSIONS

Pulmonary autograft root replacement can be performed with few complications. During follow-up, a significant increase in mild AR or more is observed. The use of a reinforcement root ring is effective in preventing progression of AR.

Cryopreserved aortic allografts for aortic root reconstruction: a single institution's experience

BACKGROUND

An evaluation of early and long-term results of aortic root replacement with cryopreserved aortic allografts and echocardiographic follow-up of allograft valve function was performed.

METHODS

From September 1989 through May 1998, 132 patients aged 17 to 77 years (mean, 50.8 +/- 14.8 years) underwent freestanding aortic root replacement with a cryopreserved aortic allograft. Eighty-six (65.1%) patients had New York Heart Association class III or IV functional status before operation, and 27 (20.5%) patients underwent emergency operation. Fifty-nine (44.7%) patients had undergone previous cardiac operations. The cause of aortic disease was acute endocarditis in 63 (47.7%) patients, healed endocarditis in 15 (11.3%), degenerative in 20 (15.2%), congenital in 20 (15.2%), failed prosthesis in 10 (7.6%) and rheumatic in 4 (3.0%). Follow-up was complete, with a mean of 42 months.

RESULTS

There were 12 hospital deaths (9.1%; 70% confidence limits [CL], 6.6% and 11.6%); 9 of them were operated on for active endocarditis (p = 0.062). Multivariate analysis determined age older than 65 years (p = 0.012) and emergency operation (p = 0.009) as independent risk factors for hospital mortality. During follow-up, 6 (5.0%; 70% CL, 3.0% and 7.0%) patients died. Cumulative survival rate for the entire group was 81.8% +/- 5.4% at 8 years. Freedom from reoperation for structural valve failure was 100%, freedom from reoperation for any cause was 96.3% +/- 1.8% at 8 years. Freedom from endocarditis at 8 years was 97.9% +/- 1.4%. Follow-up of allograft valve function showed no or trivial aortic regurgitation in 97% of patients and absence of stenosis of the allograft in 100%.

CONCLUSIONS

Aortic root replacement with cryopreserved aortic allografts can be performed with acceptable hospital mortality and long-term results. The durability of cryopreserved aortic allografts is good, and reoperation for structural valve failure is absent at 8 years.