Aortic root replacement with free-style stentless valve for aorto-left and right ventricular communication due to infective endocarditis; report of a case

Aortic root abscess remains a major determinant of both early and late results of surgical treatment of endocarditis. This complication rarely progresses to intracardiac shunt followed by cardiac failure. We report a surgical case of a 40-year-old man, who had been diagnosed as prosthetic valve endocarditis with aortic root abscess ruptured into left and right ventricle creating aorto-left and right ventricular communication. Because of complete debridment of infective and/or dead tissue, aortic root replacement was required. We used free-style stentless valve, xenograft, since homograft was not available at the time of operation. We believe that this prosthesis has easier handling and is more resistant to infection, therefore, it might be an option for infective endocarditis with aortic root abscess.     

Prosthetic valve endocarditis with extensive aortic root abscess

Prosthetic valve endocarditis with an extensive aortic root abscess usually has high mortality and morbidity. A 71-year-old male with an extended aortic root abscess following aortic valve replacement survived after full aortic root reconstruction with glutaraldehyde bovine pericardium, mitral valve replacement and full root replacement using stentless bioprosthesis. The patient is well without recurrence of infection, 18 months postoperatively. This procedure might be an alternative treatment for prosthetic valve endocarditis with an extended aortic root abscess.     

Stentless bioprosthetic aortic valve replacement after a homograft root replacement: Toronto SPV implantation after a homograft root

Stentless bioprosthetic valves for the aortic position offer excellent hemodynamic characteristics, making them an attractive choice ahead of other valve prostheses. We present a unique case in which a patient underwent aortic valve replacement with a stentless porcine valve and mitral valve repair for severe aortic and mitral regurgitation 1 year after a homograft root replacement for acute aortic endocarditis. The rationale for our approach is outlined in the context of current surgical trends.     

Aortic Valve Replacement with Stentless Porcine Bioprostheses

The implantation of stentless porcine valves (SPVs) is technically more demanding than implantation of stented bioprosthetic valves. Implantation of the Toronto SPV bioprosthesis requires an,understanding of the relationships between the leaflets and the aortic annulus and sinotubular junction. In addition to proper alignment of the three commissures within the aortic root, the diameter of sinotubular junction should not exceed the external diameter of the porcine aortic valve after completion of the operation. The Medtronic Freestyle porcine aortic root bioprosthesis can be used for subcoronary implantation as well as for aortic root replacement. Degenerative calcification of a tricuspid aortic valve is the most common cause of aortic valve disease in older patients. Implantation of stentless valves in the subcoronary position is usually feasible because the geometry of the aortic root is well maintained in these patients. The bicuspid aortic valve is the second most common cause of aortic valve disease in older patients and the most common in younger patients. These patients frequently have dilated aortic root, and the Medtronic Freestyle bioprosthesis is ideal for implantation using the root inclusion technique. Stentless porcine bioprostheses are minimally obstructive and associated with low mean systolic gradients. In addition, they have better hemodynamic performance during exercise than stented bioprostheses. For these reasons, patient-prosthesis mismatch has not been described with stentless valves. Left ventricular function after aortic valve replacement appears to be better with stentless than with stented bioprostheses. Comparative, nonrandomized studies of aortic valve replacement with stented and stentless valves suggest that the risk of cardiac death is reduced with stentless valves and the rates of valve-related complications also appear to be lower. What remains unknown is whether stentless valves are more durable than stented ones.     

Stentless bioprostheses in aortic root disease

INTRODUCTION: The availability of aortic homografts is steadily decreasing. In the meantime, stentless xenografts convey similar flow characteristics, and tissue preservation methods are improving durability. Initially, these valves were contraindicated in aortic roots with discrepancy between annulus and sinotubular junction or with extensive calcification or sepsis. With increasing experience stentless xenografts are now applied in a wide spectrum of aortic root disease. METHODS: I reviewed our own experience with stentless aortic bioprosthesis for aortic valve replacement (AVR) and more taxing root problems. I used these valves in aortic aneurysm repair, acute Type A dissection, and for endocarditis with abcess formation. I studied valve hemodynamics, regression of left ventricular hypertrophy, and comparative survival with stented bioprostheses. RESULTS: Stentless bioprostheses convey hemodynamic and possibly survival benefit through a low incidence of valve-related complications. They provide a useful alternative to aortic homografts in endocarditis, Type A dissection, and aortic aneurysm surgery. CONCLUSIONS: Stentless bioprostheses are no longer confined to AVR alone. Experience supports the use of stentless bioprostheses where aortic homografts were previously applied. With availability in a wide range of sizes.     

Clinical use of stentless aortic valves with standard and minimally invasive surgical techniques

The stentless porcine aortic valve prostheses have the potential to provide superior hemodynamic function and durability. Our institution was a trial site for the investigational device exemption (IDE) for 2 of the 3 stentless valve bioprostheses and has clinical experience in all 3 valves that are soon to be available. From July 1996 to January 2001, we have implanted 213 porcine stentless valves: the Toronto SPV (159), the Freestyle (20), and the Prima Plus (34) (current IDE). Fifty-five percent of these patients had concomitant coronary artery bypass graft procedures, 44% had isolated aortic valve replacements, and 3 patients required aortic valve and mitral valve procedures. Fifty-nine percent of the patients were men, 9% of procedures were reoperations, and 22% of patients were in New York Heart Association classification III or IV preoperatively. Extubation occurred within 5 hours for 52% of patients, median cardiothoracic intensive care unit length of stay was 1 day, and postoperative length of stay was 6 days. Reoperations for bleeding occurred in 5.3% of patients (0 in the past 12 months), atrial fibrillation in 28.2%, and permanent neurologic deficit in 1.9%. No patients required valve-related reoperations or had either sepsis or sternal infections. Operative mortality was 1.4%. We have also analyzed a subset of patients who had minimally invasive aortic valve replacement versus the standard approach and found no important differences in mortality (none), postoperative complications, cardiopulmonary bypass, or cross-clamp times. There was a trend towards earlier ambulation, less atrial fibrillation (15.8% v 24.1%), and earlier hospital discharge (5.6 days v 7.2 days). We conclude that excellent results were obtained with all 3 stentless aortic valve bioprostheses. Hospital events should be predictably low in elderly patients and those requiring concomitant procedures. Stentless aortic valve bioprostheses can be incorporated into regular cardiac surgical practice with the techniques described.     

The Freestyle stentless bioprosthesis for prosthetic valve endocarditis

We report a case of methicillin-resistant Staphylococcus aureus-induced prosthetic valve endocarditis, which was successfully treated with aortic valve replacement using the Freestyle stentless bioprosthesis. The total root and stentless design of this bioprosthesis allows for more radical removal of infected tissue and easier treatment for annular abscess, while requiring less prosthetic materials than a conventional prosthesis. This bioprosthesis thus seems to be a valuable option for active endocarditis.     

The freestyle stentless aortic bioprosthesis: more about the subcoronary technique.

Two years after aortic valve replacement with a Freestyle stentless aortic xenograft using the partial scallop inclusion technique, late prosthetic valve endocarditis developed with abscess formation in the space between the porcine and native human aortic wall. The presence of such a periprosthetic dead space exposes the patient to increased postoperative pressure gradients and the risk of superinfection.     

Aortic valve replacement with stentless porcine aortic bioprosthesis

Twenty-nine patients were entered in a clinical trial on aortic valve replacement with a stentless glutaraldehyde-fixed porcine aortic valve. This bioprosthesis is secured to the aortic root by the same technique used for aortic valve replacement with aortic valve homografts. The functional results obtained from this operation have been most satisfactory. To assess the hemodynamic benefit of eliminating the stent of a porcine aortic valve, we matched 22 patients with a stentless porcine bioprosthesis for age, sex, body surface area, valve lesion, and bioprosthesis size to 22 patients who had aortic valve replacement with a Hancock II bioprosthesis. Mean and peak systolic gradients across the aortic bioprosthesis and effective aortic valve areas were obtained by Doppler studies. Gradients across the stentless bioprosthesis were significantly lower than gradients across the Hancock II valve for every bioprosthesis size. Effective aortic valve areas of the stentless bioprosthesis were significantly larger than the valve areas of the Hancock II valve. Our data demonstrate that the hemodynamic characteristics of a glutaraldehyde-fixed porcine aortic bioprosthesis are greatly improved when the aortic root is used as a stent for the valve. This technique of implantation is expected to enhance the durability of the bioprosthesis, because the aortic root may dampen the mechanical stress to which the leaflets are subjected during the cardiac cycle.     

Bivalirudin anticoagulation for cardiopulmonary bypass in a patient with heparin-induced thrombocytopenia

PURPOSE: To describe the perioperative management in a heparin-induced thrombocytopenia (HIT) positive patient who had prosthetic valve endocarditis and an aortic root abscess. The patient underwent high-risk cardiac re-operation with the use of the alternative anticoagulant, bivalirudin. CLINICAL FEATURES: A 62-yr-old patient who underwent stentless tissue aortic valve replacement with a Toronto-SPV valve in 1998, was admitted to hospital with symptoms of stroke. A heparin infusion was started and further investigation revealed positive blood cultures. The patient developed HIT which was confirmed by laboratory tests. Echocardiographic examination performed one month later showed vegetations on the aortic tissue valve and a small aortic root abscess. The patient still tested positively for the presence of HIT antibodies and was treated conservatively with antibiotics. A repeat echocardiographic examination showed progression of the aortic root abscess and it was decided to proceed with urgent redo aortic valve surgery. Anticoagulation for cardiopulmonary bypass (CPB) was achieved with the use of a direct thrombin inhibitor (DTI), bivalirudin. Following an uneventful wean from CPB, hemostasis was achieved within 40 min. The postoperative course was uncomplicated and the patient was discharged from hospital on the seventh postoperative day. CONCLUSION: Bivalirudin is a DTI, which can be used as an alternative anticoagulant for CPB in HIT positive patients. This case report showed a favourable outcome with bivalirudin for urgent complex redo cardiac surgery requiring CPB.     

Successful aortic root replacement for prosthetic valve endocarditis using the freestyle stentless bioprosthesis: report of two cases

We report two cases of prosthetic valve endocarditis which were successfully treated with aortic root replacement using the freestyle stentless bioprosthesis. Prosthetic valve endocarditis occurred in two patients after aortic valve replacement and modified Bentall operation, respectively. The aortic annulus was severely damaged and left ventriculo-aortic discontinuity was found in both cases. We used the freestyle stentless bioprosthesis, which fits well to the destroyed aortic annulus with left ventriculo-aortic discontinuity, because of its flexibility. Postoperative echocardiography revealed excellent hemodynamic results in both cases. Although the long-term results obtained with the freestyle stentless bioprosthesis, such as resistance to bacterial infection, have not been reported, this prosthesis appears to be very useful for treatment of prosthetic valve endocarditis. We expect that this prosthesis might be a option for PVE as an alternative to a homograft.     

Use of stentless xenografts in the aortic position: determinants of early and late outcome

BACKGROUND: Whether to perform a stentless aortic valve replacement (AVR) is not well established. Our aim was to determine the outcome after AVR with stentless xenograft valves. METHODS: Between 1996 and 2001, a total of 404 patients (mean age 70.4 years) underwent a stentless AVR by one surgeon in our unit. Concomitant procedures were performed in 132 patients (33%). Twenty patients (6.4%) had undergone previous AVR. Eleven types of stentless xenograft valves were implanted: Medtronic Freestyle in 221 patients (55%), Shelhigh in 55 (14%), Shelhigh composite conduit in 33 (8%), Sorin in 26 (6%), Cryolife O'Brien in 25 (6%), Aortech-Elan in 17 (4%), Edwards Prima in 14 (4%), Toronto SPV in 7 (2%), and other valves in 6 (1%). A subcoronary implantation technique was used in 302 cases (76%), complete root replacement in 62 (15%), and a modified Bentall-De Bono procedure in 33 (8%). Mean follow-up was 19.4 months (range, 1.2 to 60.6 months). RESULTS: Overall hospital mortality was 4.2%. This was 2.4% for isolated AVR, 3.6% for AVR and coronary artery bypass grafting, 5.5% for replacement of two or more valves, and 12% for the modified Bentall procedure. On multiple logistic regression redo cardiac operation (p = 0.0006), cardiogenic shock (p = 0.001), left ventricular ejection fraction less than 0.30 (p = 0.01), modified Bentall procedure (p = 0.03), and endocarditis (p = 0.04) were predictors of in-hospital death. Five-year freedom from thromboembolism, hemorrhage, prosthetic endocarditis, structural valve deterioration, and reoperation was 97%, 99%, 99%, 98%, and 96%, respectively. Kaplan-Meier survival at 5 years was 88%. On Cox regression, cardiogenic shock (p = 0.001) and older age (p = 0.03) were adverse predictors of survival. At echocardiographic examination within 6 months from the operation, mean aortic valve gradients were 15 +/- 6 mm Hg, 12.8 +/- 3 mm Hg, 10.8 +/- 4 mm Hg, 9.3 +/- 3 mm Hg, 9.1 +/- 4 mm Hg, and 8.2 +/- 3 mm Hg for valve sizes of 19, 21, 23, 25, 27, and 29 mm, respectively. CONCLUSIONS: The availability of several stentless valve designs facilitates the surgical treatment of diverse aortic valve or root diseases with encouraging early and mid-term results. Patients requiring concomitant procedures may also benefit from the excellent hemodynamic characteristics of a stentless valve. We consider stentless AVR the treatment of choice for patients older than 60 years and those having small aortic roots.     

Stentless Porcine Bioprostheses in the Treatment of Aortic Valve Infective Endocarditis

Between January 1992 and June 1994, 23 patients underwent surgery for aortic valve endocarditis at the Department of Cardiovascular Surgery of the University of Verona; a subgroup of 10 patients underwent aortic valve replacement with a porcine stentless valve (Biocor LTDA n = 8; Toronto SPV n = 2). There were 7 males and 3 females with a mean age of 56.3 years (range, 36 to 73 years). Eight patients had active endocarditis and two had healed endocarditis. Nine patients had native valve in endocarditis, the presence of a bicuspid aortic valve in 2, and 1 patient had recurrent prosthetic valve endocarditis (PVE), 7 of whom were in New York Heart Association (NYHA) Functional Class IV. The main indications for operation were congestive cardiac failure, active sepsis, and presence of large and mobile vegetations by echo and arrhythmias. There were no operative or late mortalities in this subgroup of patients. Short-term survival is 100% at a mean follow-up time of 11.2 months (range, 4 to 18 months), with no recurrent endocarditis or valve-related complications.     

Viable cryopreserved aortic homograft for aortic valve endocarditis and annular abscesses

Six consecutive patients with active aortic valve endocarditis, including 2 with extensive subannular aortic root abscess, were successfully treated with viable cryopreserved homograft aortic valve replacement. Two patients required extensive aortic root reconstruction with an appropriately trimmed aortic homograft to cover large abscess cavities. All patients showed resolution of infection with no perioperative mortality or clinically significant morbidity. Three patients had a minor degree of aortic insufficiency on postoperative echo-Doppler study. On follow-up at 6 to 48 months, all patients were in New York Heart Association functional class I. The resistance of the unstented homograft to infection makes it an attractive choice for patients requiring aortic valve replacement for active endocarditis. The results of surgical intervention in patients with extensive aortic root involvement may be further improved by the flexibility afforded by the homograft to be "custom-fit" to the abnormal aortic root and the ability to achieve secure abnormal aortic root and the ability to achieve secure valve fixation without use of prosthetic material.     

A technique of aortic annulus enlargement with a Freestyle stentless bioprosthesis

We describe our surgical technique to manage a small aortic annulus during aortic valve replacement. Starting with the posterior annular enlargement incision described by Manouguian, a stentless porcine aortic root, with excision of the left and right porcine coronary segments and conservation of the mural wall (Freestyle MS design, Medtronic, Minneapolis, MN ), was used. The Freestyle bioprosthesis enlarges the aortic annulus using a direct suture of the valve on the enlarged annulus, and the aorta is closed by a direct suture of the mural wall of the bioprosthesis. Therefore, the aortic annulus enlargement is made only using the aortic bioprosthesis, without other material.     

Aortic Valve Replacement with the Unique Suture Line Stentless USL Porcine Valve: A New, Simple, and Safe Stentless Valve Implantation Technique

The Stentless USL, Unique Suture Line porcine valve, is a stentless bioprosthesis developed following the advantages of the studies of the physiology of the aortic root as a functional unit. The direct suturing of the porcine tissue on the soft and elastic tissue of the host's aortic annulus and root gives the bioprosthesis the possibility to follow the physiological movements of the natural valve during the cardiac cycle. For the same reason, there is decreased stress on the valve tissue, especially at the commissural level. There is less technical demand for surgeons who have limited experience with the freehand or miniroot technique due to the limited availability of the homografts because the Stentless USL valve can be implanted with the same technique used with a conventional stented valve. The implant technique used for the Stentless USL valve has advantages, especially in the small aortic calcified annulus in elderly patients where the freehand technique can be difficult and the second suture line can be dangerous (i.e., coronary ostium near the aortic ring or in calcified aortic wall). Our experience with this stentless valve in approximately 200 patients (> 70 years old) shows it to have excellent hemodynamic results even in small valve sizes. The use of this valve and the simple implantation technique avoids the need for complicated aortic root enlargement procedures.     

Results of homograft aortic valve replacement for active endocarditis

Since July 1985, cryopreserved homograft prostheses have been used for aortic valve replacement in 10 patients, aged 2 to 77 years, with active endocarditis. Five patients had positive bacterial cultures from excised valves, and all had clinical findings of uncontrolled infection while receiving appropriate antibiotics. Homograft valves (four) or valved conduits (six) were implanted for treatment of sepsis (6 patients), congestive heart failure (3) or recurrent emboli (1 patient), and complicating native (5 patients) or prosthetic valve (5) endocarditis. Staphylococci (6 patients), streptococci (3), and Candida (1) were infecting organisms. Preoperatively, Doppler echocardiography showed aortic regurgitation in all patients. At operation, 9 patients had gross vegetations, 9 had single or multiple abscess cavities, and 5 had pericarditis. Complex reconstruction of the aortic valve and annulus with homograft conduits was necessary in 6 patients (3 with previous aortoventriculoplasty). Two early deaths (ventricular failure, perioperative stroke) occurred. Mean follow-up of all operative survivors was 2.1 years (range, 0.6 to 3.6 years), and one late death resulted from arrhythmia. Homograft valve regurgitation increased in 1 patient, and 7 late survivors are asymptomatic. No patient has had recurrence of endocarditis. We conclude that cryopreserved homograft aortic valve/root replacement is an effective method for management of active endocarditis complicated by annular destruction.     

Surgical treatment for aortic periannular abscess/pseudoaneurysm caused by infective endocarditis

Delayed diagnosis or surgery sometimes causes more extensive destruction of aortic periannular abscess, or pseudoaneurysm, resulting in left ventricular–aortic discontinuity, particularly in patients with prosthetic valve endocarditis. The condition complicates the surgical procedures and causes worsening of short- and long-term outcomes. In-hospital mortality in patients with prosthetic valve endocarditis has been reported to be as high as 15–20 %, even at leading hospitals in the world. Contemporary modes of surgery for periannular abscess/pseudoaneurysm involve drainage of the cavity, radical debridement of necrotic tissue, annular reconstruction of the destroyed annulus, and root replacement using an optimal conduit. Radical debridement is of primary importance and is the universally accepted procedure, which frequently requires annular reconstruction using a pericardial patch. Conventional aortic valve replacement using a mechanical or stented biological valve, aortic valve replacement with translocation, aortic root replacement using an allograft, pulmonary autograft (Ross procedure), stentless biological valve, or a composite graft are conduits of choice. All things considered, allograft is believed to be the best conduit for a destroyed annulus because of better fit and its resistance to infection; however, recent reports have failed to confirm the superiority of allograft over other conduits in terms of long-term survival and freedom from reoperation/recurrence of infection. Short- and long-term outcomes have been studies for every type of conduit, but the selection of conduits for aortic root replacement is still controversial.     

Replacing the ascending aorta and aortic valve for acute prosthetic valve endocarditis: is using prosthetic material contraindicated?

BACKGROUND: The use of prosthetic material (rather than a homograft) for ascending aorta/aortic valve replacement (Bentall procedure) in cases of acute prosthetic valve endocarditis is controversial. We report favorable results using this technique almost exclusively (a homograft was used in only 3 patients with hematological problems) during a 12-year interval. METHODS: Twenty-eight patients (55 +/- 14 years; 22 male) underwent a Bentall procedure for acute prosthetic valve endocarditis between 1988 and 2000. Twenty-five patients had undergone previous aortic valve replacement (1 with concomitant mitral valve replacement, 4 with coronary artery bypass grafting), and 3 had had a previous Bentall operation. The median interval between initial surgery and reoperation was 13 months (range, 1 to 106). Sixty-eight percent of operations were urgent or emergencies. Ninety-three percent of patients had significant aortic regurgitation; complete annuloaortic dehiscence occurred in 71%, and in 57%, an abscess was found. Causative organisms were identified in 25 of 28 patients: Staphylococcus epidermidis (9), Staphylococcus aureus (7), Streptococcus viridans (6), Pseudomonas (2), and Legionella (1). RESULTS: Twenty-three patients had mechanical and 5 had biological valves implanted during the Bentall procedure. Hypothermic circulatory arrest was used in 64%. Hospital mortality was 11%: there was one intraoperative death, and two before discharge (one cardiac, one sepsis). Eighty-nine percent survived without stroke. During follow-up (median, 44.5 months; complete in 92%), 1 patient died of recurrent endocarditis at 4 months. CONCLUSIONS: These results indicate that prosthetic root replacement may be superior to use of a homograft for acute aortic prosthetic valve endocarditis, with only a 4% incidence of recurrent endocarditis and reoperation.     

Aortic root abscess after percutaneous coronary intervention

A 68-year-old man, who had undergone percutaneous coronary intervention for right coronary disease 2 weeks earlier, was admitted to our hospital for investigation of a fever. Blood culture and echocardiography revealed isolated aortic valve infective endocarditis. He was treated with antibiotics for more than 1 week, but echocardiography showed an aortic root abscess with severe aortic regurgitation. Thus, we performed aortic root replacement using an artificial Freestyle stentless bioprosthesis valve. The patient had an uneventful postoperative course and antibiotic treatment was continued for a further 8 weeks.