Technical considerations in reoperation for porcine bioprosthetic valve failure

Hemolysis associated with prosthetic heart valves: a review

Hemolysis is one of the potentially serious complications of prosthetic heart valves. It is usually associated with either structural deterioration or paravalvular leak. Mild, compensated hemolysis associated with mechanical heart valves is not uncommon even in the current era. Severe hemolysis is rare, however, and usually reflects paravalvular leak. The use of transesophageal echocardiography-guided operative techniques may help prevent or minimize early postoperative paravalvular leakage. There is a gamut of available therapeutic approaches-medical, transcatheter, and surgical-to this complication and therapy should be tailored to the individual patient. Novel pharmacological agents include erythropoietin and pentoxifylline. Several reports described the feasibility of transcatheter closure of paravalvular leak with coils or devices, but their effect on hemolysis is unpredictable. Surgery remains the treatment of choice in severe cases.

Percutaneous closure of prosthetic paravalvular leaks: Case series and review

BACKGROUND

Paravalvular leaks (PVLs) are a well-recognized complication of prosthetic valve replacement. Most are asymptomatic and benign, but some may cause symptoms due to a large regurgitant volume or hemolysis. Medical therapy is palliative, while reoperation carries significant morbidity and mortality. Percutaneous transcatheter closure techniques, now routinely applied in the management of pathological cardiac and vascular communications, may be adaptable to PVL closure, potentially offer symptomatic relief.

METHODS

We reviewed our experience with attempted percutaneous closure of PVLs, using data from medical and procedural records.

RESULTS

Between 2001 and 2004, 14 procedures were performed in 10 patients, all under general anesthesia, with transesophageal and radiographic guidance. Mitral (9) and aortic (1) valve replacements were involved, both mechanical and bioprosthetic. A variety of devices were used, including atrial septal occluders, patent ductus arteriosus occluders, and coils (all of label use). Six had a single procedure, which was technically successful in four: in two, the PVL could not be crossed. Four underwent a second procedure, which was technically successful in three; in one the previously deployed device was dislodged necessitating urgent, but ultimately uneventful, surgical removal and leak repair. One patient had transient severe hemolysis, which resolved after 1 week. At 1-year follow-up (9/10 pts) three had died, five had sustained symptomatic improvement while 1 patient with a residual leak still required regular blood transfusions.

CONCLUSIONS

Percutaneous closure of PVLs is time-consuming but feasible in selected patients, with a reasonable degree of technical and clinical success. A second procedure may be necessary and a variety of complications can occur.

Reoperation on stentless aortic xenografts

BACKGROUND

Stentless xenografts have been proposed as substitutes for the diseased aortic valve. Cases of valve failure requiring reoperation have thus far been sporadic. To establish the prevalence and outcome of reoperation on stentless aortic xenograft valves, all patients operated on between October 1992 and October 1996 were reviewed.

METHODS

One hundred ninety-nine patients, 94 men and 105 women aged 70+/-7 years, had stentless aortic valve replacement for aortic stenosis (in 139), insufficiency (19), or both (38). Three prostheses were used, including the Biocor PSB (Belo Horizonte, Brazil) (106), Toronto SPV (St. Jude Medical, Inc., St. Paul, MN) (52), and O'Brien-Angell (Cryolife, Atlanta, GA) (41). While the Biocor PSB and Toronto SPV prostheses are designed to be implanted freehand with inflow and outflow suture lines, the O'Brien-Angell valve requires a single suture line.

RESULTS

There were 7 (3.5%) total and 6 (3%) valve-related reoperative procedures during a follow-up extending up to 4 years (mean 26+/-20 months). All but one valve-related reoperation, due to endocarditis 36 months after implant, were early (less than 12 months after initial operation). Prevalence of valve-related reinterventions was 1%, 0%, and 12%, and freedom from reoperation at 3 years was 98%+/-2%, 100%, and 81%+/-8%, in patients receiving the Biocor PSB, Toronto SPV, and O'Brien-Angell valves, respectively (p = 0.0039). Cause of reoperation was technical in 3 (O'Brien-Angell), pannus in-growth in 1 (O'Brien-Angell), valve tear in 1 (O'Brien-Angell), and endocarditis in 1 (Biocor PSB). All patients survived replacement of the xenograft with a stented bioprosthesis (5) or homograft root (1) and were discharged after a mean hospital stay of 6+/-3 days (range, 4 to 12 days). At follow-up 15+/-8 months after reintervention (range, 6 to 34 months), all patients are symptom-free with no evidence of recurrent valve obstruction, regurgitation, or infection.

CONCLUSIONS

Reoperation for stentless xenograft failure is a rare overall event. Implant of the O'Brien-Angell valve may be associated with a higher prevalence of early reintervention because of nonstructural failure. When needed, reoperation on a stentless xenograft is generally a simple procedure and carries a low surgical risk.

The risks of reoperation for prosthetic valve dysfunction

A retrospective study was conducted on 124 patients who underwent re-replacement of previously implanted prosthetic heart valves for structural valve failure, prosthetic valve endocarditis, periprosthetic leak, a thrombosed valve, hemolysis, or prophylactic removal. In total, 85% of the explanted valves were bioprostheses, and 70% of the newly implanted valves were mechanical valves. The overall operative mortality rate was 8.1%, being 3.2% of 95 single valve recipients and 25.0% of 28 double valve recipients (P < 0.001). The overall mortality rate dropped from 13.6% of 66 patients before 1988, to 1.7% of 58 patients encountered in the last 3 years (P < 0.02). Since 1988, a third of the patients have undergone reoperation without homologous blood transfusion. A univariate analysis revealed eight operative risk factors, namely: higher values of preoperative blood urea nitrogen or total bilirubin, double valve replacement at the redo operation, NYHA class IV, urgency of reoperation, a duration of implantation of less than 3 months, reoperation in the earlier period of this study, and reexploration for bleeding or cardiac tamponade after re-replacement surgery. A multivariate statistical analysis demonstrated that preoperative blood urea nitrogen, urgency of reoperation, double valve replacement, and the duration of implantation were independent risk factors. Thus, we recommend that surgery be performed early, before the occurrence of other organ failure induced by congestive heart failure due to any form of valve dysfunction.

The risk of reoperation in patients with bioprosthetic valves

The risk of operative mortality in patients undergoing a first reoperation for bioprosthetic failure was assessed in a series of patients reoperated upon during the last two decades (1970-1990). A total of 330 such patients underwent replacement of 351 bioprostheses: 88 had aortic; 221 mitral; and 21 mitral and aortic bioprosthetic replacement. Indication for reoperation was in most cases structural valve deterioration (87%), followed by periprosthetic leak (7%) and endocarditis (6%). The operative mortality was significantly higher in patients who preoperatively were in New York Heart Association Functional Class IV or had a lower left ventricular function, in those reoperated because of prosthetic infection, and in those reoperated on an emergency basis. Structural valve deterioration was associated to a substantially low risk; operative mortality has improved in recent years, regardless of the indication for reoperation, partly due to the increasing experience and improved surgical techniques. Our results indicate that in recipients of bioprosthetic valves, careful follow-up with closer surveillance of valve and cardiac function and earlier prosthetic replacement might contribute to reducing the risk of reoperation.