Retrospective clinical analysis of stented vs. stentless porcine aortic bioprostheses

OBJECTIVE

The study was designed to compare hemodynamic performance, structural failure and survival of patients undergoing aortic valve replacement (AVR) with a composite aortic stented or stentless porcine bioprosthesis.

METHODS

From January 1990 to June 1999, the clinical data of 725 patients undergoing AVR with stented porcine aortic bioprosthesis were reviewed. We defined two groups of patients with similar clinical characteristics: 202 patients receiving aortic stented and 205 patients stentless valves. The two patients groups were similar in age, sex, valve lesion, valve size, preoperative New York Heart Association (NYHA) class status and follow-up.

RESULTS

The number of patients available for follow-up, excluding hospital and late mortality, reoperations and patients lost to follow-up, was 157 for the stented and 175 for the stentless group. There was a higher incidence of rheumatic heart disease in the stented (59%) vs. stentless group (44%), (P=0.003). Fewer patients had prior aortic bioprosthetic dysfunction in the stented (7.6%) compared to the stentless group (25%) (P<0.001). The mean intensive care unit stay, hospital mortality and late mortality were similar (P, NS). The total complication rate was higher in the stented (12%) than the stentless (3.4%)(P=0.005). Valve related death was higher in the stented (2.5%) than the stentless (0%) (P=0. 049). Postoperatively, the aortic effective orifice area (AEOA) was larger (P<0.001) and the transvalvular peak and mean gradients were lower in the stentless group (P<0.001). The leaflet tissue degeneration analysis was 8.0% in patients at risk for stented and 0. 6% for stentless (P=0.001). Actuarial analysis disclosed no statistical difference in patient survival between groups (P=0.18). Reoperations were less frequent in the stentless group (P=0.010).

CONCLUSIONS

Hemodynamic benefits in the stentless group were evident and expressed by larger AEOA, lower gradients, better left ventricular remodeling with significant decrease of the left ventricular mass. Lower complication rates, lower reoperation rates, less leaflet tissue degeneration, and lower valve related mortality rates were seen in the stentless group. A controlled clinical comparison trial with longer follow-up will be required to confirm these clinical and hemodynamic benefits.

Porcine stentless valve/bovine pericardial conduit for right ventricle to pulmonary artery

BACKGROUND AND OBJECTIVES

We assessed the long-term outcome of a glutaraldehyde-preserved bovine pericardial conduit containing a stentless composite porcine aortic valve.

METHODS

Between November 1985 and May 1995, 33 stentless porcine valves attached to bovine pericardial conduits were used in 33 patients with complex congenital cardiac malformations. These patients required a conduit between the right ventricle and the pulmonary artery because of an absent or inadequate pulmonic artery. All patients were approached by midsternotomy. One patient with pulmonic atresia and an interventricular septal defect required left thoracotomy for ligation of collaterals.

RESULTS

Of the initial 33 patients, clinical follow-up was performed in 23 discharged patients (70%) for 1.7 to 10.5 years. The echo-Doppler analysis performed in each of the 23 followed patients showed excellent conduit and valve function in all but 4 patients, in whom a valve gradient of 60 mm Hg was noted. There was no tissue structural failure noticed in this study.

CONCLUSIONS

The SJM Biocor (Belo Horizonte, Brazil) bovine pericardial stentless valved conduit performed well as a substitute for the right ventricle to pulmonary artery connection.

Porcine mitral stentless valve mid-term clinical results

OBJECTIVES

Time testing is essential with any valvular procedure, especially when a new concept is introduced such as the mitral stentless valve. Our purpose is to evaluate the results obtained over 4 years with this operation, particularly to attest the impact of preservation of annulo ventricular continuity on the long term results of these patients.

METHODS

From March 1992 to August 1996, 120 patients had their mitral valves replaced with a porcine stentless mitral valve. The observation period was 54 months with total patients follow-up of 3424 months with a mean of 28.5 months. The age ranged from 11 to 72 years (mean 35.22 +/- 14.98). There were 73 females (60.8%) and 47 males (39.2%). The predominant etiology was rheumatic heart disease. Associated procedures were performed in 12 patients (10%), and the great majority of the patients were in functional class III and IV (NYHA).

RESULTS

Hospital mortality occurred in seven patients (5.83%) non valve related except for one early case of endocarditis. Early reoperation related to technical failure were necessary in 4 patients without mortality. Follow-up was accomplished in 101 patients and ranged from 2 to 54 months. Late reoperations were required in 16 patients (nine due to mitral insufficiency, five because of endocarditis and two for mitral stenosis). Most reoperations were related to technical failure. Among the 82 patients presently in control, 72 showed a competent mitral stentless valve, eight with stable mild mitral regurgitation and in two a decreased mitral orifice. Hemodynamic performance of the valve has been excellent in this group, particularly in patients with left ventricular dysfunction.

CONCLUSION

Although technical complexity remains the main cause of reoperations with this valve, experience has shown that it not only provides preservation of the left ventricular function but also promised significant increase of the ejection fraction in patients with poor left ventricular function.

Late complications after surgical exclusion of the thoracic aorta

Two patients who underwent surgical exclusion of the thoracic aorta for chronic dissecting aneurysms of the descending aorta died 4 and 8 years after surgery due to complications in part related to the operative technique. One patient developed pseudoaneurysm of the proximal aortic stump with fatal exsanguination through an aortapulmonary fistula. The other patient developed progressive dilatation of the remaining abdominal aorta with subsequent rupture. The surgical approach in this case was extremely difficult because of the previous exclusion procedure which determined a highly demanding reoperation. Although surgical exclusion of the thoracic aortic may be a useful technique in some situations, we must be aware of its early and late complications and, in our opinion, it should be seen only as an alternative treatment for very special patients with diseases of the descending thoracic aorta.

Surgical technique of implanting the stentless porcine mitral valve

The new stentless porcine mitral valve was developed to serve as an anatomically correct substitute for a diseased mitral valve. Extensive acute animal experimentation was performed, and from this the logical sequence for selecting the correct valve size and the specific technique for implanting it were determined. The following are the major steps to successfully implant a mitral stentless valve: First, mitral valve complex analysis must be done to determine the correct procedure to be performed and the feasibility of using the stentless mitral valve. Second, the correct size of stentless mitral valve must be chosen. Third, the papillary muscle anatomy must be assessed to determine the site and number of sutures necessary for securely holding the new origin of the new chordae. Fourth, the papillary muscle sutures must be anchored to the free pericardial edge of the new chordal origin. Fifth, the chordal alignment with both trigonal areas must be perfect. Sixth, the annulus may be sutured using either continuous or interrupted sutures. Perioperative echocardiography, preferably transesophageal echocardiography, should be done in every patient. Although reoperation was necessary in 5 patients (non-valve-related), the results in 74 patients (3 early and 3 late non-valve-related deaths excluded) followed up for at most 26 months (mean, 14 months) have been excellent. The quality of the results obtained in this initial clinical trial has reinforced our current preference for this valve in patients requiring mitral valve replacement. Longer follow-up is required to confirm that these good results continue.

Porcine stentless aortic valve in re-replacements and acute aortic valve endocarditis

Between June 1990 and June 1993, 135 patients received a porcine stentless aortic valve (PSAV) at our institution. In this group, there were 33 patients in whom the stentless valve was used to replace a previously inserted malfunctioning aortic valve prosthesis (n = 19) or to treat acute aortic valve endocarditis (n = 14, five native, nine prosthetic endocarditis). There was one hospital death caused by multiple organ failure in a patient with endocarditis and preoperative cerebral stroke. Two patients died after hospital discharge; one suffered sudden death following a pacemaker failure four month after surgery and the other died due to Candida albicans sepsis after a prolonged antibiotic treatment. There were two reoperations; one to correct a dehiscence of the proximal suture line and the other to replace a degenerated valve 3.5 years after implantation in a 14 year old boy. All operative survivors were followed clinically with serial color Doppler echocardiography. No recurrence of endocarditis was detected. Aortic root reconstruction was achieved even in the presence of multiple abscesses. All but one patients showed a normally functioning valve with none or minimal aortic insufficiency. In our opinion the PSAV is an excellent aortic valve substitute for patients with damaged aortic annulus, because it promotes aortic root remodeling, decreases the incidence of postoperative paravalvular leaks and helps to prevent endocarditis recurrence.

Heterologous mitral valve transplant: the first 50 patients clinical analysis

From March 1992 to August 1993, 50 patients underwent mitral valve replacement with the new heterologous stentless mitral bioprosthesis in our institution. The development of this heart valve substitute, its technique of implantation and the results observed in the first group of 50 patients have had us to review the initial experience. The surgical protocol included an accurate mitral valve complex analysis, adequate valve size selection, attachment of the papillary muscle to the new chordal origin and approximation of the stentless mitral to the patient's annulus. There was one hospital death (2%), not related to the valve or to the technique and four reoperations: two due to endocarditis, one because of a perivalvular leak and one due to a mismatched stentless valve. The late mortality (4%) was not valve-related. The follow-up has shown excellent valve performance with improved left ventricular function in the great majority of the patients. Based on the current analysis, it can be stated that reproducibility of the surgical technique and the excellence of the clinical follow-up may contribute favorably to a better quality of life and longer valve durability in patients requiring mitral heart valve replacement.

Porcine stentless aortic heart valve substitute mid-term clinical follow-up

From May 1990 to January 1994, 120 patients underwent aortic valve replacement with the use of the Biocor porcine aortic stentless heart valve (BPASHV). There were 83 male and 3 female patients. The age ranged from 11 seventy-six (76) years with a mean of 36. Eighty-five patients were under 40 years of age. Sixty-four patients underwent their first aortic valve replacement due to rheumatic heart disease, 30 because of prosthetic valve failure and of those: 20 were due to primary tissue failure and in 10 due to prosthetic endocarditis, native aortic bicuspid valve in 11 and senile calcificant aortic valve disease in four. Thirty-three patients had aortic annular related pathology. Their preoperative functional class revealed 61 patients in class III and 59 in class IV. The longest follow-up in this aortic group was 42 months with a mean of 26. The surgical technique used rendered consistent and reproducible results. There was a hospital mortality of six patients (5%). The mortality was not valve related. The hospital morbidity in 14 revealed full recovery of all patients. There were four late reoperations, in two due to recurrent endocarditis and in the last two because of paravalvar leak. There was a late mortality of four patients (non valve related). The follow-up of these patients revealed full competent aortic stentless valve in 97 patients and only minor jet in nine. Most patients are in functional class I and II. The Aortic stentless concept has proven to be outstanding with the use of the Biocor Aortic stentless valve throughout the current follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Porcine stentless mitral heart valve substitute: short term clinical data

Beginning March 1992 to February 1994, 65 patients were submitted to mitral valve replacement using the porcine mitral stentless heart valve. This group took in 65 patients, their age ranged from four to 65 with a mean of 26 years. Forty patients were below years of age. The major indication was rheumatic heart disease sequelae in 50 patients, mitral valve endocarditis in six, myomatous degeneration in four and in five previous mitral prosthetic valve was replaced due to tissue failure. The preoperative functional class revealed 35 patients in class III and 30 in class IV. The longest follow-up was 23 months with a mean of 12. The surgical technique used rendered consistent and reproducible results. There was a hospital mortality of two patients or 3.1%. The hospital morbidity revealed full recovery of all patients. There were three patients reoperated because of valve endocarditis in two and in one due to partial dehiscence of the suture at the annular level. All three patients had full recovery after a reoperation. There was a late mortality of two patients, non valve related. The follow-up of these patients revealed full competent stentless mitral valve in 50 patients and in nine minor to mild jets were encountered by color echo-Doppler. Most patients are in functional class I and II. The stenless concept has prove to be outstanding in the mitral position throughout the current follow-up of close to 2 years.(ABSTRACT TRUNCATED AT 250 WORDS)

The new stentless aortic valve: clinical results of the first 100 patients

From May 1990 to August 1993, 100 patients underwent aortic valve replacement using the stentless porcine aortic valve. There were 69 males and 31 females. The mean age was 36 (range 11-76) years. Of 70 patients under 40 years of age, 20 were less than 20 years old. Indications included rheumatic heart sequelae in 55 patients (first valve replacement), prosthetic failure in 20, endocarditis in 13, congenital aortic bicuspid valve in four, degenerative disease in four and senile calcified aortic valves in four. Twenty patients had aortic annular related pathology. There were 15 associated surgical procedures. Forty-three patients required aortic root enlargement. There were approximately equal numbers of patients in New York Heart Association (NYHA) functional classes III and IV. The hospital mortality rate was 6%; 14 patients who experienced hospital morbidity had a full recovery. Two late reoperations were performed in patients with primary valve endocarditis; their recovery was uneventful. Four late deaths were not valve related. Comparative echo Doppler analysis before and after operation demonstrated good improvement of left ventricular function in nearly all patients. The valve was competent in 96% of patients and the remainder displayed minor jets without haemodynamic significance. The valve coaptation was stable in all patients. Use of the stentless porcine aortic valve in this first 100 patients has provided excellent clinical results with a follow-up of 41 months. Further follow-up and close observation will be required to analyse the outcome of this new valve and procedure with time.

[Secondary sternotomy in pediatric heart surgery]

PURPOSE

To analyze the results observed in children who underwent surgical correction of congenital anomalies, in whom the sternotomy was left open to avoid postoperative heart compression.

METHODS

Fourteen children with mean age of 11 months, with different kind of congenital malformations who underwent definitive correction were submitted to the technique of delayed sternal closure. The indication was: hemodynamic instability due to sternal approximation (8), uncontrolled bleeding (4) and preventive (2). In all patients a bovine pericardial patch was sutured to the skin edges allowing a good decompression of the heart.

RESULTS

Among the 14 children, two died in the immediate postoperative period, before the secondary sternal closure. There were two other deaths in the remaining 12 children who underwent sternal approximation, one due to acute pneumothorax and the other due to low cardiac output. The incision was closed after hemodynamic stabilization was achieved, and happened usually around the 3rd postoperative day. There were no cases of mediastinal infection.

CONCLUSION

The technique of delayed sternal closure is an important approach in pediatric cardiac surgery and can be life saving. In our experience a bovine pericardial patch proved to be effective in decompressing the heart and also in protecting the mediastinal cavity.

[Atriofascicular connection with slow conduction and longitudinal dissociation. Electrophysiologic evidence and clinical implications]

We report on a patient with paroxysmal left bundle branch block-like tachycardia with electrophysiologic findings suggestive of nodoventricular pathway (ventricular pre-excitation dependent on slowing of AV conduction, and accessory pathway with exclusive anterograde conduction). There was no pre-excitation during sinus rhythm but it was brought on by intravenous verapamil. Atrioventricular node conduction curves showed no signs of duality. Diagnosis of an atriofascicular pathway with decremental properties was based on the following findings: 1) absence of AV dissociation during reciprocating tachycardia; 2) absence of fusion beats or narrowing QRS complexes during tachycardia; 3) advancement of right ventricular activation with late atrial extrastimuli delivered during antidromic tachycardia at a time of low right atrium refractoriness; 4) observation that earliest ventricular endocardial electrogram during tachycardia (activation mapping) was simultaneous with the right bundle potential; 5) surgical ablation of the accessory pathway by endocardial incision at the right anterior aspect of the tricuspid ring, far away from the AV node region. Evidences showing anterograde longitudinal dissociation of the accessory pathway included cycle length alternation during tachycardia and duality of accessory pathway conduction times and refractory periods. We hypothesize that reentry occurring in such AV node-like structure could give to a pre-excited tachycardia with AV dissociation mimicking antidromic tachycardia associated with nodoventricular pathway.

[Surgery for Wolff-Parkinson-White syndrome in the first year of life]

A case of surgical treatment for reentrant atrioventricular tachycardia in a 7 months old child is reported. Episodes of tachycardia were repetitive and long-lasting, often leading to signs of hemodynamic impairement, and were not controlled by antiarrhythmic drugs. The electrophysiologic study showed a circus-movement tachycardia utilizing a concealed accessory pathway located at the anterior septal aspect of tricuspid anulus. The child underwent successful surgical treatment by the endocardial technique. Few minutes after weaning from extracorporeal circulation, developed T wave inversion followed by acute right ventricular dysfunction and ventricular fibrillation. Others ischemic like episodes, maybe as a result of coronary artery spasm, occurring in the next 6 hours were successfully treated with isosorbide dinitrate. At 18 months follow-up, the child is free of tachycardia and has normal atrioventricular conduction.

Anatomically complete heterograft mitral valve substitute: surgical technique and immediate results

The use of a totally anatomical mitral valve heterograft as a mitral valve substitute has been proven to be technically feasible. A new stentless mitral porcine heart valve substitute was therefore developed to match the physiology and flow characteristics of the left ventricle and mitral valve complex, and tested in non-survival animal experiments. Having sought the approval of the Hospital Ethics Committee and the consent of each individual patient, this valve was implanted into 18 patients with diseased mitral valves. The duration of the procedure is approximately the same as for standard mitral valve replacement. The sizing of the valve and the anchoring of the sutures to the papillary muscle, although very straightforward, do require adherence to a protocol. The immediate clinical results are encouraging, although the first patient required a reoperation because of a patient/valve mismatch. All patients, including the patient reoperated, are in functional class I after four to 26 weeks of follow up. The patients will be followed by monthly clinical and Doppler echocardiographic examinations, as they have been so far, for the next 12 months, and annually thereafter.

Clinical results with the Biocor porcine bioprosthesis

In order to evaluate our clinical results with the use of the Biocor prosthesis, a total of 1,101 patients were studied. Follow-up was from 1 to 96 months (mean 48); cumulative follow-up in the aortic group (385 patients) was 1,230 patient years and in the mitral group (716 patients) 3,018 patient years. Mitral patients had 102 late complications (14.24%), and aortic patients had 51 (13.2%). A total of 220 patients were under 20 years of age (176 mitral, 44 aortic). Intrinsic valve failure in this subgroup was found in 43% of mitral patients and 29% of aortic patients. Prosthetic endocarditis was more frequent in the aortic group (45%) than in the mitral group (29.9%). Sixty-two patients were reoperated, with a hospital mortality of 12.6%. Reoperation was more frequent in the mitral group and in patients under 20 years of age. The actuarial curve free mortality related to the bioprosthesis was 97.1% (32 patients). At the 8-year follow-up, 96.9% of the aortic versus 95.2% of the mitral group were free of valve dysfunction, and the majority were in Classes I or II of the New York Heart Association (NYHA) classification. The incidence of reoperation, although significant, is acceptable, especially since the bioprosthesis offers a safer alternative than mechanical prostheses followed for similar periods. Analysis of our results suggests the need for continued research for an ideal bioprosthesis.

[Congenital absence of left pericardium simulating tumor of the anterior mediastinum]

The authors report a case of a patient presenting atypical dyspnea symptom. The physical examination, the chest roentgenogram and EKG were abnormal; the echocardiogram showed an abnormal mass compressing the outflow tract of the right ventricle (RV). These data were confirmed by a computerized tomography. The cardiac catheterization showed a heart deviation to the left and a RV outflow tract gradient of 10 mmHg. Consequently a surgery was necessary. The surgical findings presented an absence of the left pericardium and no tumor was found. This is a rare entity that may be misdiagnosed as other heart diseases but this is the first case in which a tumor of the anterior mediastinum was suspected.

The use of PTFE graft to correct anomalous drainage of persistent left superior vena cava

A new technique to correct persistent left superior vena cava (LSVC) drainage into the left atrium is described in a 14-year-old patient with situs inversus, left atrial isomerism common atrium, and mitral valve regurgitation. During surgery, occlusion of the LSVC markedly increased the venous pressure, precluding its ligation. Because of the malposition of the heart and the unusual atrial anatomy, correction with an intra-atrial baffle was not attempted. After correcting the intra-cardiac anomaly, the LSVC was divided and anastomosed to the "right" atrial appendage using a segment of PTFE graft. The postoperative course was uneventful and an angiogram demonstrated excellent performance of the graft.

[Tetralogy of Fallot associated with total anomalous drainage of the pulmonary veins. Report of 2 cases]

The authors report on two cases of tetralogy of Fallot (TF) associated with total anomalous pulmonary venous return to the coronary sinus. The clinical manifestations in both children were the same as of classical TF and diagnosis was confirmed by cineangiography. The patients underwent total surgical correction and the first one died in the immediate post-operative period. The second patient had an uneventful recovery. The rarity of this association is the main reason of this report where clinical and surgical findings are discussed.