Excellent cardiac surgical outcomes in paediatric indigenous patients, but follow-up difficulties.

BACKGROUND: Indigenous Australians' infant mortality is three times that of non-Indigenous Australians. Indigenous children's mortality from rheumatic heart disease is 17-21 times that of non-Indigenous male and female children, respectively. No studies have looked specifically at the operative outcomes of cardiac surgery in paediatric Indigenous patients in Australia and little is known about their follow-up. AIMS: To describe operative outcomes of all Indigenous paediatric cardiac surgical patients at a single Australian tertiary hospital and assess their follow-up. METHODS: Database review of retrospectively collected data of all Indigenous paediatric patients who had cardiac surgery performed at The Prince Charles Hospital, Brisbane between 2002 and 2009 (112 patients, 123 operations). Follow-up was assessed by chart review and time to first post-discharge echocardiogram recorded in the hospital database. RESULTS: Eighty-one percent of operations were congenital heart disease related and 19% of operations were rheumatic heart disease related. Common co-morbidities included respiratory (9.7%) and renal dysfunction (0.8%). Common complications were, bleeding/tamponade 4.1%, cardiac arrest 4.1% and new atrial arrhythmia 2.4%. Mortality was 1% for congenital operations and 4.4% for rheumatic operations. Only 33% of patients had follow-up within eight weeks documented through letters or chart entry. Only 77.5% of patients had a documented follow-up echocardiogram. DISCUSSION: Operative outcome in Indigenous paediatric patients is similar to that found in the global literature. The follow-up for such an excellent surgical outcome has been disappointing. A coordinated action within and between health, health related and social institutions with sufficient resources will assist.

Postoperative junctional ectopic tachycardia (JET).

Postoperative junctional ectopic tachycardia (JET) is a potential life-threatening tachycardia that mainly occurs after surgical correction of congenital heart defects. The arrhythmia itself or the related treatment has significant clinical impact on the postoperative course and intensive care stay. In general, JET is a self-limiting disorder that usually resolves within one week. However, JET occurs usually within the first 24 to 48 hours after corrective surgery, when systolic and diastolic function of the heart is impaired. Thus, the rapid heart rate leads to an acute further deterioration of cardiac output that requires adequate treatment. The diagnosis of JET is made by the typical ECG-appearance with narrow QRS-configuration at a rate of 170 to 260 bpm and AV-dissociation. A variety of different therapeutic strategies have been tested in postoperative and congenital/spontaneous JET. Treatment success is usually defined as a stable decrease in the ventricular rate below 140-150/min, the possibility of atrial pacing and thereby the improvement of cardiac output. Optimal success is the reinstitution of sinus rhythm. Many of the treatment strategies reported are based on specific institutional treatment protocols. These include conventional supportive treatment, specific medical antiarrhythmic therapy, specific forms of pacing and surface cooling. Today, the administration of high doses of amiodarone usually leads to adequate control of the rate and enables pacing. Surgical intervention or catheter ablation of the HIS-bundle is rarely necessary. This article reviews the literature about JET over the past years and offers a specific treatment protocol.

Quality assurance of paediatric cardiac surgery: a prospective 6-year analysis.

OBJECTIVE: To audit effective quality assurance methods to monitor outcomes following paediatric cardiac surgery at a single institution. METHODS: All patients undergoing cardiac surgery from January 1996 to December 2001 were enrolled prospectively. Patients were stratified by complexity of surgical procedure into four groups, with Category 4 being the most complex procedure. Outcome measures included death, length of admission and morbidity from complications. RESULTS: A total of 1815 patients underwent 1973 surgical procedures. Of these, 1447 (73.3%) were cardiopulmonary bypass procedures, and 543 (27.5%) were more complex (Category 3 and 4) procedures. Median patient age was 3.5 years (range, 1 day-20 years) and patient weight 15.0 kg (range, 900 g to 90 kg). Sixty-six patients (3.6%) died during the study period. Of the procedures in 1996, 22.7% were classified as complex compared with 29.2% of procedures in 2001. The annual surgical mortality ranged from 1.9-4.7% (P = 0.20), and when mortality was adjusted for complexity of surgery, there was no significant yearly variation in the mortality rate (P = 0.57). Analysis of individual surgeon's results showed no significant difference in the mortality rate by complexity of surgery performed (P = 0.90). Mean ventilation times did not change significantly over time (P = 0.79). The yearly incidence of significant neurological complications ranged from 0.6% to 4.5% and the incidence of arrhythmias from 4.2% to 8.0%. No difference was detected between the years. CONCLUSIONS: Stratifying complexity of surgery proved valuable in monitoring surgical outcomes and detecting differences in performance over time as large subgroups were created for analysis.

Outcome following surgical closure of secundum atrial septal defect.

OBJECTIVE: To assess the current outcome of surgical closure of secundum atrial septal defects (ASD) in an Australian paediatric population. METHODOLOGY: A retrospective chart review of 87 children, aged 2 months to 15 years, was performed for surgery between August 1995 and March 1999. RESULTS: There were no deaths in the patients studied. Approximately one in four patients (24.1%) experienced complications requiring further management. Complication rates were similar to those published previously. However, one in nine patients (11.5%) required surgical drainage of a pericardial effusion. A total of five of 87 (5.7%) patients developed post-pericardiotomy syndrome (PPS), of whom four required pericardiocentesis. The risk for developing a pericardial effusion requiring drainage or PPS was more than twice in children older than 5 years of age at the time of surgery compared to those aged under 5 years, although there was an insufficient number of subjects in the study to prove this statistically (Odds ratio 2.31). CONCLUSIONS: Most patients have an uncomplicated postoperative course following surgical closure of secundum ASD. However, a significant minority (24.1%) do develop complications requiring further management and have a correspondingly longer period of hospitalization. Patients older than 5 years of age were identified as being potentially at greater risk for the development of PPS or a pericardial effusion requiring drainage. Further research needs to be performed to clarify this.

Transesophageal echocardiographic abnormalities in a case of cardiac sarcoidosis.

Sarcoidosis is a granulomatous disease that may involve multiple organ systems, including the heart. Manifestations include atrial and ventricular arrhythmias, conduction abnormalities, congestive cardiac failure, pericarditis, and sudden death. Whereas cardiac involvement is a relatively common finding at autopsy, antemortem diagnosis is often missed because the clinical manifestations are nonspecific, and the sensitivity and specificity of investigations are low. We report a case of a 62-year-old woman who had clinically significant cardiac sarcoidosis associated with echocardiographic abnormalities that had not been reported previously in association with this condition.

The homograft aortic valve: a 29-year, 99.3% follow up of 1,022 valve replacements.

BACKGROUND AND AIM OF THE STUDY: The study aim was to elucidate the advantages and limitations of the homograft aortic valve for aortic valve replacement over a 29-year period. METHODS: Between December 1969 and December 1998, 1,022 patients (males 65%; median age 49 years; range: 1-80 years) received either a subcoronary (n = 635), an intraluminal cylinder (n = 35), or a full root replacement (n = 352). There was a unique result of a 99.3% complete follow up at the end of this 29-year experience. Between 1969 and 1975, homografts were antibiotic-sterilized and 4 degrees C stored (124 grafts); thereafter, all homografts were cryopreserved under a rigid protocol with only minor variations over the subsequent 23 years. Concomitant surgery (25%) was primarily coronary artery bypass grafting (CABG; n = 110) and mitral valve surgery (n = 55). The most common risk factor was acute (active) endocarditis (n = 92; 9%), and patients were in NYHA class II (n = 515), III (n = 256), IV (n = 112) or V (n = 7). RESULTS: The 30-day/hospital mortality was 3% overall, falling to 1.13 +/- 1.0% for the 352 homograft root replacements. Actuarial late survival at 25 years of the total cohort was 19 +/- 7%. Early endocarditis occurred in two of the 1,022 patient cohort, and freedom from late infection (34 patients) actuarially at 20 years was 89%. One-third of these patients were medically cured of their endocarditis. Preservation methods (4 degrees C or cryopreservation) and implantation techniques displayed no difference in the overall actuarial 20-year incidence of late survival endocarditis, thromboembolism or structural degeneration requiring operation. Thromboembolism occurred in 55 patients (35 permanent, 20 transient) with an actuarial 15-year freedom in the 861 patients having aortic valve replacement +/- CABG surgery of 92% and in the 105 patients having additional mitral valve surgery of 75% (p = 0.000). Freedom from reoperation from all causes was 50% at 20 years and was independent of valve preservation. Freedom from reoperation for structural deterioration was very patient age-dependent. For all cryopreserved valves, at 15 years, the freedom was 47% (0-20-year-old patients at operation), 85% (21-40 years), 81% (41-60 years) and 94% (>60 years). Root replacement versus subcoronary implantation reduced the technical causes for reoperation and re-replacement (p = 0.0098). CONCLUSION: This largest, longest and most complete follow up demonstrates the excellent advantages of the homograft aortic valve for the treatment of acute endocarditis and for use in the 20+ year-old patient. However, young patients (< or = 20 years) experienced only a 47% freedom from reoperation from structural degeneration at 10 years such that alternative valve devices are indicated in this age group. The overall position of the homograft in relationship to other devices is presented.

The middle aortic syndrome: an important feature of Williams' syndrome.

The middle aortic syndrome, with diffuse narrowing of the thoracic and abdominal aorta, was present in 10 of 18 patients with Williams' syndrome (55%). There were 3 thoracic coarctations, and 2 abdominal coarctations, with gradients greater than 20 mmHg across the zone of narrowing. Seven patients had mild renal arterial stenosis, and 6 had visceral arterial stenoses. Ten were hypertensive. Measured dimensions of the aortic lumen failed to increase with age in 3 males who had serial angiographic studies. One developed mesenteric arterial stenosis, with mild bilateral renal arterial stenoses, between the ages of 9 and 19 years. Aortic intravascular ultrasound performed in 2 patients confirmed abnormally thick vessel walls with small lumens. Diffusely narrowed and thick-walled stiff arteries, lacking elastin, are a feature of Williams' syndrome. The arteriopathy tends to progress with age, and systemic hypertension is common in teenagers and beyond. The middle aortic syndrome was present in more than half our patients, and does not necessarily reflect a bias because of cardiologic referral. Aortography with measurement of aortic diameters and delineation of the visceral branches is an important requirement for complete evaluation of patients with Williams' syndrome.

Both beta(2)- and beta(1)-adrenergic receptors mediate hastened relaxation and phosphorylation of phospholamban and troponin I in ventricular myocardium of Fallot infants, consistent with selective coupling of beta(2)-adrenergic receptors to G(s)-protein.

BACKGROUND: In adult human heart, both beta(1)- and beta(2)-adrenergic receptors mediate hastening of relaxation; however, it is unknown whether this also occurs in infant heart. We compared the effects of stimulation of beta(1)- and beta(2)-adrenergic receptors on relaxation and phosphorylation of phospholamban and troponin I in ventricle obtained from infants with tetralogy of Fallot. METHODS AND RESULTS: Myocardium dissected from the right ventricular outflow tract of 27 infants (age range 21/2 to 35 months) with tetralogy of Fallot was set up to contract 60 times per minute. Selective stimulation of beta(1)-adrenergic receptors with (-)-norepinephrine (NE) and beta(2)-adrenergic receptors with (-)-epinephrine (EPI) evoked phosphorylation of phospholamban (at serine-16 and threonine-17) and troponin I and caused concentration-dependent increases in contractile force (-log EC(50) [mol/L] NE 5.5+/-0.1, n=12; EPI 5.6+/-0.1, n=13 patients), hastening of the time to reach peak force (-log EC(50) [mol/L] NE 5.8+/-0.2; EPI 5.8+/-0.2) and 50% relaxation (-log EC(50) [mol/L] NE 5.7+/-0.2; EPI 5.8+/-0.1). Ventricular membranes from Fallot infants, labeled with (-)-[(125)I]-cyanopindolol, revealed a greater percentage of beta(1)- (71%) than beta(2)-adrenergic receptors (29%). Binding of (-)-epinephrine to beta(2)-receptors underwent greater GTP shifts than binding of (-)-norepinephrine to beta(1)-receptors. CONCLUSIONS: Despite their low density, beta(2)-adrenergic receptors are nearly as effective as beta(1)-adrenergic receptors of infant Fallot ventricle in enhancing contraction, relaxation, and phosphorylation of phospholamban and troponin I, consistent with selective coupling to G(s)-protein.

Late complications of tissue glues in aortic surgery.

BACKGROUND: Tissue glues are used in cardiothoracic surgery as an adjunct to operative procedures where tissues are frail, as in aortic dissection, or where added hemostasis is required. This study was undertaken to review the use of tissue glue in our institution over a 5.5-year period. The aim of the study was to identify any potentially glue-related complications. METHODS: A review of tissue glue use for the period from January 1993 to September 1998 was performed and pre-, intra-, and postoperative parameters were collected. After some unusual surgical findings, of special interest was a range of pathology found at late reoperation. RESULTS: A total of 67 cases of tissue glue use were identified, with the majority of operations for type A dissection (76%). There were two intraoperative deaths. Twenty-seven of 65 patients (41%) required 29 further open chest operations; of these, 17 were for acute problems of bleeding or tamponade. Twelve patients (18%) underwent late reoperations months to years later. Nine of these patients, concentrated in two operative groups (7 patients with aortic valve resuspension and 2 patients who had undergone "switch" operations for transposition of great vessels), displayed complications related to the application of gelatin-resorcinol-formaldehyde (GRF) tissue glue. CONCLUSIONS: Indications for tissue glues in cardiothoracic surgery must be carefully considered. We have reviewed our use of some tissue glues in acute type A aortic dissections and in pediatric cardiac patients and have discontinued the use of GRF glues because of unsatisfactory long-term complications.

A clinical comparison of arterial and atrial repairs for transposition of the great arteries: early and midterm survival and functional results.

BACKGROUND: The early experience in correction of simple transposition of the great arteries (TGA) involved redirection of atrial inflow to re-establish systemic and pulmonary blood flow, the basis of the Senning and Mustard operations. Since 1984, however, the arterial switch operation (Jatene) has been increasingly used. It appears that with experience the peri-operative mortality rate for arterial repair is comparable to that for atrial repairs, while the late morbidity rates have generally favoured arterial repair, with sequelae such as obstruction of venous inflow, dysrhythmias, systemic atrioventricular valve dysfunction and impaired systemic ventricle function being more common following atrial repairs. METHODS: A retrospective review of patients surgically treated for TGA at the Prince Charles Hospital. RESULTS: Between April 1973 and July 1994, 103 patients with simple TGA underwent surgical correction using one of three standard approaches currently advocated (arterial switch/Jatene, Senning or Mustard operations). Fifty-one Jatene, 31 Senning and 21 Mustard operations were performed. Associated procedures included closure of ventricular septal defect, right and left ventricular outflow tract resection and pulmonary artery band removal. The coronary artery anatomy was found to be suitable in all except two patients when the Jatene operation was planned; both these patients had a Senning procedure without mortality. There were nine peri-operative deaths (4 Jatene, 2 Senning, 3 Mustard), and five late deaths (1 Jatene, 1 Senning, 3 Mustard). Follow-up was maintained to a mean time of 60.5 months (range, 9 days to 203 months). In the Jatene group there were five anastomotic stenoses (all involving the neo-pulmonary artery), three cases of arrhythmias (two postoperative supraventricular tachycardia and one nodal rhythm) and two pulmonary valve stenoses. In the Senning group there were four anastomotic stenoses (three involving pulmonary vein and one causing superior vena cava (SVC) inlet obstruction) and four cases of arrhythmias (with one requiring permanent pacemaker insertion). In the Mustard group there were two cases of SVC obstruction and two permanent pacemaker insertions for bradycardia. CONCLUSIONS: These early and midterm results suggest that the arterial switch operation has comparable overall mortality to, and less morbidity than, the atrial repairs for TGA with the retention of left ventricle to systemic arterial connection, which may provide improved long-term results.

The Medtronic Intact xenograft: an analysis of 342 patients over a seven-year follow-up period.

Three hundred forty-two patients from December 1985 to January 1993 received 352 Medtronic Intact porcine xenograft valves (zero-pressure glutaraldehyde-fixed with toluidine blue anticalcification agent). The follow-up was 99.4% complete with a mean of 3.14 years (3 months to 7.9 years). The mean patient age was 64 years (range, 16 to 82 years) and the median age was 67 years. There were 14 aortic valve replacement patients (11.9%) and 62 mitral valve replacement patients (29.2%) who preoperatively were in New York Heart Association class IV to V. The hospital mortality was 8.4% +/- 2.9% (aortic valve replacement, 5.9%; mitral valve replacement, 9.4%; tricuspid valve replacement, 7.6%). Actuarial patient survival at 7 years was 65% +/- 5% (aortic valve replacement, 77% +/- 5%; mitral valve replacement, 63% +/- 5%). At 7 years, the freedom from thromboembolism was 74% +/- 4%, freedom from endocarditis 93% +/- 2%, and freedom from reoperation 90% +/- 3%. Reoperation was required for endocarditis (7 patients), periprosthetic leak (6), and 2 of 3 cases of structural deterioration. The actuarial freedom from structural deterioration at 5 years was 97% +/- 3%. The combined incidence of all important morbid valve-related events was analyzed with an actuarial freedom at 7 years of 63% +/- 3%. The durability of the Medtronic Intact is at least equal to that of other porcine bioprostheses. The relevant important time-frame of 7 to 12 years of follow-up has just begun, and possibly the reoperation rate for intrinsic value failure and the low incidence of calcification in the elderly patient may be showing improved characteristics of this valve. No stronger inferences are possible at this stage of the 7-year follow-up.

Allograft aortic valve replacement: long-term follow-up.

Aortic valve replacement using an allograft aortic valve has been performed on 804 patients. From December 1969 to May 1975, 124 patients received a nonviable allograft valve sterilized by incubation with low-dose antibiotics and stored for weeks by refrigeration at 4 degrees C (series 1). From June 1975 to January 1994, 680 patients received viable allograft valves, now cryopreserved early within 2 hours of collection from transplant recipient donors, 6 hours for multiorgan donor valves and 23 hours (mean) for autopsy valves from donor death. The 30-day mortality was 8.9% +/- 5% (95% confidence limits) for series I and 2.8% +/- 1% (95% confidence limits) for series II. Actuarial patient survival including hospital mortality at 15 years was 56% +/- 5% for series I and 62% +/- 5% for series II. The probability of a thromboembolic event was low, freedom at 15 years being 95% +/- 1% for patients receiving allografts with or without associated coronary bypass procedures and 81% +/- 5% for patients having allografts with other associated procedures (eg, mitral valve operations). Actuarial freedom from endocarditis was similar for the two series, 91% +/- 3% (series I) and 94% +/- 2% (series II) at 15 years. The freedom from valve incompetence, from reoperation for all causes, and from structural deterioration demonstrated clearly the inferiority of the 4 degrees C stored allograft valves. For structural deterioration as identified clinically, at reoperation and at death, freedom from this event at 15 years was 45% +/- 6% for series I and 80% +/- 5% for series II (p value for the difference is 0).(ABSTRACT TRUNCATED AT 250 WORDS)

Root replacement for all allograft aortic valves: preferred technique or too radical?

From November 1985 to January 1994, 146 patients have received a viable cryopreserved allograft for aortic root replacement. The follow-up was complete, with all events included to March 1st, 1994. The median age of patients was 49 years; 83.6% were male. Valve dysfunction (91 patients), primary aortic wall disease (45 patients), and a combination of both (10 patients) were the indications for aortic root replacement. The current operative mortality is 1.7% (three deaths in 172 patients to July 1st, 1994). Four late deaths have occurred, with an 8-year actuarial survival of 85% +/- 8% (95% confidence limits). Endocarditis (two events) and thromboembolism (four events) had a low incidence. Structural deterioration (three events) and reoperation for all causes (nine events) have constituted low morbidity and are compared with the results after non-root allograft implantation techniques. The clinical and echocardiographic evidence indicates that the immediate results of valve function with root replacement are superior. But no statistical difference between aortic root replacement and non-root procedures is apparent at 8 years, indicating that a longer follow-up is required before the answer to the question "preferred technique or too radical" can be answered.

An analysis of risk factors for death and mode-specific death after aortic valve replacement with allograft, xenograft, and mechanical valves.

From September 1967 to January 1990, a total of 2100 patients underwent 2366 aortic valve replacements with a variety of allograft, xenograft, and mechanical valves. Concomitant procedures were performed in 764 patients. Actuarial survival at 12 years was 59.6% (70% confidence limits 57.8% to 61.4%). Hazard function for death was highest immediately after operation, falling to merge with a slowly rising phase of risk at approximately 3 months. Actuarial freedom from sudden death at 12 years was 88.0% (70% confidence limits 86.7% to 89.3%). The shape of the hazard function for sudden death was similar to that for death. Actuarial freedom from death with cardiac failure at 12 years was 87.9% (70% confidence limits 86.5% to 89.2%). The shape of the hazard function for death with cardiac failure was also similar to that for death. Risk factor analysis revealed the important deleterious impact on long-term survival resulting from impaired left ventricular structure and function because of aortic valve disease. No current-era valve used in this study (allograft, xenograft, or mechanical) was a risk factor for death. Both aortic wall disease and endocarditis necessitating aortic valve replacement substantially decreased long-term patient survival. Aortic valve replacement is advisable much earlier in the natural history of aortic valve disease before secondary left ventricular damage occurs.

Aortic valve infection. Risk factors for death and recurrent endocarditis after aortic valve replacement.

Patients (n = 195) undergoing aortic valve replacement (n = 209) for native or prosthetic valve endocarditis were studied to determine risk factors for death and recurrent endocarditis and also to determine the valve type least likely to be associated with recurrent endocarditis. Ten-year survival was 60%, the highest risk of dying occurring within the first 3 postoperative months. Risk factors for death in this early phase included increased urea concentration, higher New York Heart Association functional class, prosthetic valve endocarditis, infection status (lower in patients with healed endocarditis), longer duration of cardiopulmonary bypass, and nonuse of an allograft valve. In the late phase (beyond 3 months), risk factors included age at operation and Staphylococcus aureus infection (only in New York Heart Association functional class V). Ten years after aortic valve replacement, 79% of valves were free of recurrent endocarditis. The highest risk of recurrence was in the first 4 months. Longer duration of cardiopulmonary bypass was a weak risk factor for recurrent endocarditis in the early phase, and in the late phase risk factors were S. aureus infection (only in New York Heart Association functional classes III, IV, and V) and the use of now discontinued biologic valves. Allograft aortic valve replacement was shown to be associated with a low and constant risk of recurrent endocarditis, whereas other valve types were associated with a high early risk. The allograft valve should be the preferred replacement device for aortic root infection.

Allograft aortic valve replacement: long-term comparative clinical analysis of the viable cryopreserved and antibiotic 4 degrees C stored valves.

Aortic valve replacement with or without concomitant procedures was performed using an allograft aortic valve in 534 patients. From December 1969 to May 1975 (group I), a 4 degrees C stored valve was used (124 patients) and from June 1975 to July 1990 (group II), a cryopreserved valve (410 patients) was used. The 30-day mortality was 8.9% (confidence limits [CL] 6.2%-12.3%) for group I and 2.7% (CL 1.9%-3.8%) for group II. Actuarial patient survival including early hospital mortality at 14 years was 57% for group I and 71% for group II (p = 0.014). Actuarial freedom from thromboembolism for all patients (n = 534) was 94% at 14 years, and for patients who underwent isolated aortic valve replacement with or without coronary artery bypass graft (n = 457) was 97% at 14 years (p = 0.017). Actuarial freedom from allograft valve endocarditis at 14 years was 92% in group I and 94% in group II (p = 0.36). The actuarial freedom from moderate or severe allograft valve incompetence at 14 years was 50% (group I) and 78% (group II) (p = 0.27). Reoperation was undertaken for endocarditis, leaflet structural deterioration (SD), or technical reasons. The actuarial freedom from reoperation (all causes) at 14 years was 63% (group I) and 86% (group II) (p = 0.39). Reoperation for SD occurred in 34 patients in group I and three patients in group II. The actuarial freedom from reoperation for SD at 14 years was 67% (group I) and 95% (group II) (p = 0.001). To reflect a more accurate depiction of the prevalence of SD, patients were analyzed according to the development of "assumed structural deterioration" (at reoperation, at death with moderate or severe allograft valve incompetence and macroscopic valve deterioration on autopsy, and in the presence of moderate or severe allograft valve incompetence in patients not undergoing reoperation). The actuarial freedom from "assumed structural deterioration" at 14 years was 51% (group I) and 85% (group II) (p = 0.000003). The long-term results confirm the low incidence of thromboembolism and endocarditis regardless of the method of preservation and demonstrate the overall acceptable performance of the viable cryopreserved allograft valve and its superiority over the 4 degrees C stored valve.

A study of the cells in the explanted viable cryopreserved allograft valve.

From June 1975 to December 1987, 231 patients underwent aortic valve replacement with a viable cryopreserved allograft aortic valve. Throughout this era, a uniform procurement and preservation was used to maintain leaflet fibroblast viability. The allograft valve was obtained from coroner's autopsies within 24 hours of death, and more recently from organ donors, incubated for 24 hours in low dose antibiotic solution followed immediately by cryopreservation (mean time interval 39 hours after donor death). Viability was ensured by monitoring glucose utilization of the aortic and pulmonary valves and by demonstrating fibroblast growth in tissue cultured from the pulmonary valve. A uniform protocol for valve preparation was used during the entire experience. Nine allograft aortic valves have been obtained by eight reoperations (two were for leaflet degeneration) and one autopsy. The time intervals from implantation to explantation were 2 months, 10 months, 20 months, 22 months, 2.2 years, 5 years, 8.3 years, 9.2 years, and 10.8 years. Histologic examination of the leaflet tissue disclosed a variable degree of cellularity, ranging from a highly cellular matrix (9.2 years) to minimal cellularity (20 months). Within the same valve (10 months), one leaflet was completely acellular with a moderate degree of cellularity in the other two leaflets. The competent valve recovered at autopsy (8.2 years) was essentially acellular. Fibroblasts could consistently be cultured from leaflets in which viable cells were seen histologically. Chromosomal analysis of cultured cells from a valve leaflet (9.2 years) that was implanted with a donor and recipient sex mismatch demonstrated persistence of donor cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term results of the viable cryopreserved allograft aortic valve: continuing evidence for superior valve durability.

From December 1969 to May 1975, 124 patients underwent aortic valve replacement with an allograft aortic valve sterilized by incubation in a low dose antibiotic solution and stored by refrigeration at 4 degrees C (4 degrees C stored valve group). From June 1975 to December 1987, 231 patients received an allograft aortic valve, sterilized by the same low dose antibiotic solution, but stored by cryopreservation in liquid nitrogen at -196 degrees C (cryopreserved valve group). The 4 degrees C stored valves were essentially nonviable, whereas the cryopreserved valves were viable at implantation. Of the 355 aortic valve replacements, associated procedures were performed in 127 patients. The 30-day mortality was 8.9% (confidence limits [C.L.] 6.2% ... 12.3%) (4 degrees C stored) and 4.8% (C.L. 3.3% ... 6.7%) (cryopreserved). Actuarial survival was similar in both groups, being 71% and 67% at 10 years in the 4 degrees C stored and cryopreserved valve groups, respectively (P = .18). The probability of a thromboembolic event was low, but appeared higher in the 4 degrees C stored valve group (actuarial freedom at 10 years, 90%) than the cryopreserved valve group (actuarial freedom at 10 years, 98%) (P = .01) probably related to associated mitral valve surgery. The actuarial freedom from allograft valve endocarditis at 10 years was 94% and 95% for the 4 degrees C stored and cryopreserved valve groups, respectively (P = .23). Reoperation was undertaken in 34 patients in the 4 degrees C stored group and 12 patients in the cryopreserved valve group for leaflet degeneration, endocarditis, or technical reasons.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of aortic valve replacement with viable cryopreserved and fresh allograft valves, with a note on chromosomal studies.

We examined the long-term clinical function and fate of allograft aortic valves, preserved by two differing methods, for aortic valve replacement: (1) fresh allografts stored at 4 degrees C refrigeration (group I) and (2) viable allografts cryopreserved in liquid nitrogen at -196 degrees C (group II). A total of 316 aortic valve replacement operations were performed, 124 in group I (December 1969 to May 1975) and 192 in group II (June 1975 to December 1986). Concomitant surgical procedures (eg, coronary artery bypass grafting and mitral valve replacement) were necessary in 120 operations. The overall immediate 30 day mortality was 6.0% (confident limits 4.6% to 7.7%), and the survival rates were 83% at 4 years and 60% at 15 years. Endocarditis and technical factors concerning reoperation showed no difference between the two groups according to parametric estimates and hazard function analyses. However, there was a marked difference in reoperation for valve degeneration: 23 patients in group I and 0 patients in group II. The freedom from reoperation for valve degeneration at 10 years was 89% for group I and 100% for group II, and at 15 years it was 59% for group I. The hazard function for group I reflected the late rising risk of degeneration. The freedom from thromboembolism of both groups (aortic valve replacement with or without bypass grafting) was 97% at 10 years and 96% at 15 years. Group II explanted valves (operation for technical malalignment reasons) has consistently shown evidence of persisting viability on tissue culture, on metabolic studies, and on histologic appearances. Chromosomal studies have shown the donor origin of these cells. The superior results with the cryopreserved valve is considered to be due to persisting viability, which appears to be the key to durability.