Freestanding Root Research Articles

A Rodent Model of The Ross Operation: Syngeneic Pulmonary Artery Graft Implantation in A Systemic Position

The Ross operation for aortic valve disease has regained new interest due to its outstanding long-term results. Nonetheless, when employed as freestanding root replacement, the possible dilation of the pulmonary autograft and subsequent aortic regurgitation is described. Several animal models have been proposed. However, these are usually limited to ex-vivo models or in-vivo experiments with relatively expensive large animal models. In this study, we sought to establish a rodent model of pulmonary artery graft (PAG) implantation in a systemic position. A total of 39 adult Lewis rats were included. Immediately after euthanasia, the pulmonary root was harvested from a donor animal (n=17). Syngeneic recipient (n=17) and sham-operated (n=5) rats were sedated and ventilated. In the recipient group, the PAG was implanted with an end-to-end anastomosis in infra-renal abdominal aortic position. Sham-operated rats underwent only transection and re-anastomosis of the aorta. Animals were followed with serial ultrasound studies for two months and post-mortem histological analysis. The median PAG diameter in the native position was 3.20 mm (IQR=3.18-3.23). At follow-up, the median diameter of the PAG was 4.03 mm (IQR=3.74-4.13) at 1 week, 4.07 mm (IQR=3.80-4.28) at 1 month, and 4.27 mm (IQR=3.90-4.35) at 2 months (p<0.01). Peak systolic velocity was 220.07 mm/s (IQR=210.43-246.41) at 1 week, 430.88 mm/s (IQR=375.28-495.56) at 1 month, and 373.68 mm/s (IQR=305.78-429.81) at 2 months (p=0.02) and did not differ from the sham-operated group at the end of the experiment (p=0.5). Histological analysis did not show any sign of endothelial thrombosis. This study showed that rodent models may allow for the evaluation of the long-term adaptation of the pulmonary root to a high-pressure system. A systemically placed syngeneic PAG implantation represents a simple and feasible platform for the development and evaluation of novel surgical techniques and drug therapies to further improve the outcomes of the Ross operation.

Back to the root: a large animal model of the Ross procedure.

The excellent clinical outcomes of the Ross procedure and previous histological studies suggest that the pulmonary autograft has the potential to offer young patients a permanent solution to aortic valve disease. We aim to study the early mechanobiological adaptation of the autograft. To this end, we have reviewed relevant existing animal models, including the canine models which enabled Donald N Ross to perform the first Ross procedure in a patient in 1967. Two research groups recently evaluated the isolated effect of systemic pressures on pulmonary arterial tissue in an ovine model of a pulmonary artery interposition graft in the descending aorta. While this model is ideal to study the artery's biological response and the effect of external support, it does not recreate the complex environment of the aortic root. The freestanding Ross procedure has been performed in pigs and sheep before. These studies offered valuable insights into leaflet growth and histological remodeling, yet may be less relevant to adults undergoing the Ross procedure, as pronounced autograft dilatation was achieved by using small, rapidly growing animals. Therefore, a large animal model remains needed to determine the ideal conditions and surgical technique to ensure long-term autograft remodeling and valve function. We set out to develop an ovine model of the Ross procedure performed as a freestanding root replacement, acknowledging that the sheep's specific anatomy and the setting of an animal laboratory would mandate several modifications in surgical strategy. This article describes the development, surgical technique and early outcomes of our animal model while highlighting opportunities for further research.

Contemporary Ross procedure outcomes: medium- to long-term results in 214 patients.

Our goal was to present 2 decades of our experience with the Ross procedure and its sequential modifications, adopted since 2010, to improve the reoperation rate. We performed a single-centre, retrospective review of database information and medical notes about the implantation technique: the freestanding root. We compared era 1 (1997-2009) and era 2 (2010-2019). Between 1997 and 2019, a total of 214 Ross procedures were performed (71% men, median age 24 years) [interquartile range (IQR) 15-38]. Of these, 87% had various forms of congenital-dysplastic aortic valves. The median cross-clamping and bypass times were 173 (IQR 148-202) and 202 (IQR 182-244) min. The median postoperative stay was 6 days (2-77). Thirty-day mortality was 0.5%. The median follow-up time was 8.2 years (IQR 3.9-13.2). Survival at 10 and 20 years was 97% and 95%; freedom from greater than moderate aortic regurgitation or aortic valve intervention was 91% and 80%; and 93% of the patients were in New York Heart Association functional class I. Twenty (21%) patients operated on during era 1 and 6 (9%) during era 2 underwent autograft reoperations. The median follow-up time was 14.3 (IQR 11.5-17.4) and 4.8 (IQR 2.5-7) years. Freedom from autograft reoperation was 87% and 69% at 10 and 20 years, with no significant difference between eras. Freedom from homograft reoperation was 96% and 76% at 10 and 20 years. The presence of aortic regurgitation, infective endocarditis and era 1 were predictors of autograft reoperation. Male gender and era 1 were predictors of neoaortic root dilatation. The contemporary modified Ross procedure continues to deliver excellent results and should remain part of the strategy to treat children and young adults requiring aortic valve replacement.

Ovine model of the Ross procedure as freestanding root replacement - surgical technique

Ovine model of the Ross procedure as freestanding root replacement - surgical technique

Early results from a prospective, single-arm European trial on decellularized allografts for aortic valve replacement: the ARISE study and ARISE Registry data.

OBJECTIVES Decellularized aortic homografts (DAH) may provide an additional aortic valve replacement option for young patients due to their potential to overcome the high early failure rate of conventional allogenic and xenogenic aortic valve prostheses.METHODSA prospective, European Union-funded, single-arm, multicentre, safety study was conducted in 8 centres evaluating non-cryopreserved DAH for aortic valve replacement.RESULTSOne hundred and forty-four patients (99 male) were prospectively enrolled between October 2015 and October 2018, mean age 33.6 ± 20.8 years; 45% had undergone previous cardiac operations. Mean implanted DAH diameter 22.6 ± 2.4 mm and mean durations for the operation, cardiopulmonary bypass and cross-clamp were 341 ± 140, 174 ± 80 and 126 ± 43 min, respectively. There were 2 early deaths (1 LCA thrombus on day 3 and 1 ventricular arrhythmia 5 h postop) and 1 late death due to endocarditis 4 months postoperatively, resulting in a total mortality of 2.08%. One pacemaker implantation was necessary and 1 DAH was successfully repaired after 6 weeks for early regurgitation following subcoronary implantation. All other DAH were implanted as a free-standing root. After a mean follow-up of 1.54 ± 0.81 years, the primary efficacy end points peak gradient (mean 11.8 ± 7.5 mmHg) and regurgitation (mean 0.42 ± 0.49, grade 0–3) were excellent. At 2.5 years, freedom from explantation/endocarditis/bleeding/stroke was 98.4 ± 1.1%/99.4 ± 0.6%/99.1 ± 0.9%/99.2 ± 0.8%, respectively, with results almost identical to those in an age-matched Ross operation cohort of 212 patients (mean age 34 years) despite DAH patients having undergone >2× more previous procedures.CONCLUSIONSThe initial results of the prospective multicentre ARISE trial show DAH to be safe for aortic valve replacement with excellent haemodynamics in the short follow-up period.

Long-term adaptive versus maladaptive remodelling of the pulmonary autograft after the Ross operation.

Following the Ross operation, the pulmonary autograft undergoes structural changes (remodelling). We sought to determine the extent, nature and possible determinants of long-term remodelling in the different components of the pulmonary autograft. Ten pulmonary autografts and 12 normal control valves (6 pulmonary and 6 aortic) were examined by conventional histology, immunocytochemistry and electron microscopy. The structural changes were quantified by morphometry. The leaflets from free-standing root replacement valves demonstrated thickening to levels comparable to the normal aortic leaflets, largely due to the addition of a thin layer of 'neointima' formed of radial elastic fibres, collagen bundles and glycoaminoglycans, on the ventricular aspect of the leaflets. The leaflets of valves from sub-coronary implantation demonstrated a significantly thicker fibroelastic layer on the ventricularis and calcium deposition in the fibrosa. The media of the explanted valves showed increased number of lamellar units to levels comparable to normal aortic roots. Electron microscopy of valves inserted as free-standing roots showed increased organization into continuous layers. However, intralamellar components showed varying degrees of 'disorganization' in comparison to those in the normal aortic media. In addition, there was a marked increase in the number of vasa vasorum with thickened arteriolar wall in the outer media and adventitia. Following the Ross operation, in the very long term, all components of the autograft showed varying degrees of remodelling, which was judged to be largely adaptive. Defining the type, determinants and possible functional effects of remodelling could help in understanding and optimizing the results of the Ross operation.

Valve-sparing root replacement for freestanding pulmonary autograft aneurysm after the Ross procedure

ObjectiveAutograft dilatation is the main long-term complication following the Ross procedure using the freestanding root replacement technique. We reviewed our 25-year experience with the Ross procedure with a special emphasis on valve-sparing reoperations. MethodsFrom 1991 to 2016, 153 patients (29.6 ± 16.6 years; 29.4% pediatric) underwent a Ross operation at our institution with implantation of the autograft as freestanding root replacement. The follow-up is 98.7% complete with a mean of 12.2 ± 5.5 years. ResultsMortality at 30-days was 2.0%. Echocardiography documented no or trivial aortic regurgitation in 99.3% of the patients at discharge. Survival probability at 20 years was 85.4%. No case of autograft endocarditis occurred. Autograft deterioration rate was 2.01% per patient-year, and freedom from autograft reoperation was 75.3% at 15 years. A reoperation for autograft aneurysm was required in 35 patients (22.9%) at a mean interval of 11.1 ± 4.6 years after the Ross procedure. A valve-sparing root replacement was performed in 77% of patients, including 10 David and 17 Yacoub procedures with no early mortality. Three patients required prosthetic valve replacement within 2 years after a Yacoub operation. At latest follow-up, 92% of all surviving patients still carry the pulmonary autograft valve. Freedom from autograft valve replacement was 92.1% at 15 years. ConclusionsUsing the David or Yacoub techniques, the autograft valve can be preserved in the majority of patients with root aneurysms after the Ross procedure. Reoperations can be performed with no early mortality, a good functional midterm result, and an acceptable reintervention rate.

Long-term Evaluation of the Ross Procedure in Acute Infective Endocarditis

Optimal valve substitute for young patients with aortic valve endocarditis remains controversial. Given its better resistance to infection, the Ross procedure is an attractive alternative to prosthetic valve replacement or homograft implantation. The objective of this study was to assess long-term outcomes of the Ross procedure in this indication. From January 1991 to April 2017, 190 patients underwent a Ross procedure at our institution. Acute endocarditis was the indication for operation in 19 patients, including 6 patients with a bicuspid aortic valve. The pulmonary autograft was implanted as freestanding root replacement in all patients. The clinical follow-up is 100% complete, with a mean of 12.0 ± 5.7 years. The mean age of the study population was 35.9 ± 11.5 years. Moderate or severe aortic regurgitation was present in 84.2% of the patients. Systemic embolization had occurred in 36.8% of the patients. The mean aortic cross-clamp time was 126 ± 24 minutes. The median length of stay on the intensive care unit was 1 day. Mortality at 30 days was 5.3% (1 patient with gastrointestinal bleeding). Echocardiography at hospital discharge documented no or trivial aortic regurgitation in all patients. No case of recurrent endocarditis affecting the autograft occurred. One patient (0.4% per patient-year) was reoperated 1.8 years after the Ross procedure for homograft endocarditis. Three patients (15.8%) were reoperated for autograft aneurysm. The Ross procedure is a safe and effective alternative to prosthetic valve replacement or homograft implantation in selected young patients with acute endocarditis with a low rate of recurrent infection.

The David Procedure for Salvage of a Failing Autograft After the Ross Operation

Dilatation of the pulmonary autograft is a major fear after the Ross procedure. We analyzed the results after reoperation for autograft dysfunction using a valve-sparing reimplantation technique (David procedure). From 1995 to 2012, 645 Ross operations were performed, with 630 (98%) of these as freestanding root replacements (mean follow-up, 8.3 ± 4.6 years). Forty-nine autograft reoperations occurred in 46 patients (0.89%/patient-year). Between 2005 and 2013, reoperation using a David procedure was performed in 18 of 35 patients (52%) with autograft dilatation at a mean interval of 11 ± 3.2 years after the Ross operation. The mean age of 18 patients receiving a David procedure as reoperation was 49.8 ± 13.9 years; 83% were male. The 30-day reoperative mortality was zero. The mean vascular graft size used for reimplantation was 29.5± 1.7 mm. At a mean follow-up time of 3.2 ± 2.3 years (100% complete), all patients (18 of 18) were alive andinNew York Heart Association functional class I. One patient (5%) needed valve replacement for recurrent aortic regurgitation 2.6 years after the David procedure. In the remaining patients (95%), freedom from aortic regurgitation of grade 2 or greater was 100% at 3 years (regurgitation grade <1, 14 of 17; 82%). Aortic valve gradients were clinically insignificant at 5.8 ± 2.1 mm Hg. Performing a David procedure was successful in the vast majority of patients with dilatation of the pulmonary autograft after a Ross operation and revealed good function of the preserved autograft at midterm follow-up. Reoperations could be performed with low perioperative morbidity and mortality.

The Ross procedure: suitable for everyone?

In 1967, Donald Ross transferred the patient’s own pulmonary valve into the aortic root. Although results of this technique were encouraging, the Ross procedure did not gain widespread popularity until the late 1980s when surgeons started to implant the pulmonary autograft as a freestanding full root replacement with reimplantation of the coronary arteries. However, frequent dilatation of the pulmonary autograft was observed using the freestanding full root replacement technique. In contrast, the original subcoronary implantation technique and aortic root inclusion technique prevented dilatation in the long-term. Through advancing know-how in aortic root surgery and confidence, the Ross procedure has also been used in combined procedures and complex clinical presentations with good long-term results, which encourage continual use. However, the Ross procedure is a complex operation; careful patient selection and experience of the surgeon are mandatory requirements to achieve satisfactory results.

The wide spectrum of aortic root dilatation after the Ross operation.

[first paragraph of article] The Ross root replacement is the only technique that guarantees long-term viability of all the component parts of the root. The normal aortic root performs extremely sophisticated functions which are closely linked to its structure, dynamics and viability. This has been shown to translate into clinically-relevant endpoints, such as survival and quality of life. The insertion of the pulmonary autograft as a freestanding root guarantees optimal relationship between the component parts with no distortion. Although the pulmonary valve is known to adapt to the new environment, there is continuing concern about the risk of long-term autograft dilatation and aortic regurgitation.5 We here describe two patients with considerably different types of changes in shape and size of the aortic root, in comparison to two age- and gender-matched controls.

A Single-Center Experience With the Ross Procedure Over 20 Years

The Ross procedure offers several potential advantages in a young patient population. The widespread use of the procedure is still limited due to the technical challenge. Pulmonary homograft stenosis and autograft dilatation remain a matter of concern. We present the long-term outcome in a single center with special emphasis on mortality and need for valvular reintervention. All patients who received a Ross procedure as freestanding root replacement (modified Yacoub technique) at our institution between 1991 and 2011 were followed. Descriptive statistical methods and Kaplan-Meier analyses were performed. A total of 246 patients (191 males, 55 females) underwent the Ross procedure during the study period. There were 176 adults and 70 pediatric patients with an average age of 36 ± 10 and 10 ± 5 years, respectively. The median follow-up was 10 years. Twelve (4.9%) subjects were lost to follow-up. Early mortality was 1.6%. Overall mortality was comparable with an age and sex matched population for adult patients. The linearized risk for reoperation per patient-year was 0.6% for the autograft and 0.6% for the right ventricular outflow tract, with a mean time to surgery of 6.4 ± 4.9 years. Overall freedom from reintervention was 95% at 5 years, 88% at 10 years, and 81% at 15 years. The Ross procedure provides good early results and an excellent long-term survival. It represents an excellent method of aortic valve replacement in children and young adults. Root reinforcement techniques and aortic reduction plasty may be beneficial, especially in adult patients with native aortic valve regurgitation.

Reoperation After the Ross Procedure: Incidence, Management, and Survival

The risk of reoperation on the autograft and homograft is the major long-term drawback of the Ross procedure. The incidence and clinical implications of reoperations after the Ross procedure are reported. Between March 1992 and February 2010, 336 consecutive patients had a Ross procedure (mean follow-up, 6.2±4.9 years). Autograft implant technique was freestanding root replacement in 269 patients, subcoronary implantation in 52 patients and a modified root replacement with the autograft included in a Valsalva tube graft in 15. Subsequently, 38 patients (11.3%) underwent reoperations, for autograft dilatation in 23 and a significant autograft insufficiency in 9, at 9.6±3.7 years and 2.6±3.9 years, respectively. Aortic and pulmonary infective endocarditis occurred in 3 patients. Three patients underwent a non valve-related cardiac reoperation. Three patients received a transcatheter pulmonary valve implantation after 12.2±1.7 years. At 15 years, freedoms for autograft and homograft explantation (with 95% confidence interval) were 83.3% (77.4%- to 9.2%) and 92.8% (87.6% to 97.9%), respectively. Native aortic valve regurgitation, indexed aortic annulus diameter exceeding 1.35 cm/m2 and autograft diameter were risk factors for dilated autograft reoperation (hazard ratio, 3.23 [95% confidence interval, 1.19 to 8.81], p=0.02; 3.83 [0.9 to 16.33], p=0.07 and 1.2 per mm [1.01 to 1.41], p=0.03), respectively. Autograft dilatation was the leading cause of reoperation in patients who underwent root replacement. Long-term follow-up is mandatory to determine whether modifications of the operative technique could limit autograft dilatation.

Aortic Root Physiology Late After a “Perfect” Ross Operation: Magnetic Resonance Imaging Study of Three Operative Techniques

In order to define physiological properties of the autograft root, magnetic resonance imaging (MRI) findings relative to three different operative techniques were compared with those of control subjects. Twenty-three patients, 18/5 M/F, aged 32 ± 9 years, underwent MRI assessment of the aortic root. Patients with normally functioning autograft valve and at least 4 years of follow-up (average 5.6 ± 1.9, range 4-10 years) were selected for each technique: six subcoronary (Group 1), nine inclusion (Group 2), and eight freestanding root (Group 3). Results were compared among patient groups and with seven control subjects, 6/1 M/F, aged 30 ± 2 years (P = ns). Morphological and functional properties were defined using transverse and paracoronal views, during systole and diastole. Mean aortic size in each group was greater than control, except for the LV-aortic junction and the sinus of Valsalva in Group 1 (26 ± 5 vs. 23 ± 3 mm, P = 0.2 and 33 ± 6 vs. 30 ± 5 mm, P = 0.3). Aortic valve plane rotation (P = 0.02) and root dilatation (P = 0.02) were more common in Group 3. Altered valve opening dynamics and asymmetrical aortic flow profile were also more common in Group 2 (P = 0.03) and Group 3 (P = 0.04). Distensibility was significantly reduced at sinus level in Group 2 and 3 compared with control (4.1 ± 3.5% and 3.6 ± 4.4% vs. 9.0 ± 4.7%, P = 0.03). Asymmetrical aortic flow profile was more common in patients with aortic dilatation (P = 0.05) and with severely reduced (<4%) root elasticity (P = 0.06). Among the three techniques, only subcoronary grafting allows preservation of physiological autograft valve dynamics, aortic flow and distensibility, at all root levels, late after operation. These findings may have relevant implications in the selection of the ideal Ross technique.

Aortic Valve Replacement with the Medtronic Freestyle Xenograft Using the Subcoronary Implantation Technique

Aortic Valve Replacement with the Medtronic Freestyle Xenograft Using the Subcoronary Implantation Technique

Ross Operation for Bicuspid Aortic Valve Disease in Adults: is it a Valid Surgical Option?

Objective - The validity of the Ross operation as freestanding root replacement in adult patients with bicuspid aortic valve disease has lately been questioned. We have analyzed retrospectively our results in 23 adult patients (19 males) operated for bicuspid aortic valve disease ad modum "Ross" employing a freestanding root replacement technique. Design - In 9 patients the dominant aortic valve lesion was stenotic (aortic stenosis group) and in the remaining 14 patients it was aortic insufficiency (aortic insufficiency group). The fate of the pulmonary autograft in the two groups was studied. The intraoperatively measured aortic and pulmonary annuli diameters from the two groups were compared with those from a population of normal looking aortic and pulmonary valves matched for body surface area. Results - The aortic insufficiency group needed significant reduction of the aortic annulus diameter to conform to the size of the pulmonary autograft. The pulmonary autograft annuli in this group were significantly larger in diameter than the ones in the aortic stenosis group. The mean pulmonary annulus diameter in the aortic stenosis group was, on the other hand, significantly smaller when compared with that in the normal matched population. After a mean follow-up period of about 19 months, the aortic insufficiency group showed significant dilatation of the neo-aortic sinuses. Between the two groups, the remaining echocardiographic variables remained either stable or improved at follow-up. Conclusion - Pre-existing larger diameters of the aortic and pulmonary annuli in the aortic insufficiency group combined with the significantly increased left ventricular end-diastolic diameters, may predispose these patients to significant dilatation of the unsupported aortic sinuses after a Ross operation. This dilatation does not, however, lead to increase in the autograft valve insufficiency at short-term follow-up if the aortic annulus and the distal ascending aorta are tailored to the size of the pulmonary autograft. Ross operation, employing freestanding aortic root replacement technique, may therefore be recommended in adult patients with bicuspid aortic valve disease with excellent short-term results.

The in vitro hydrodynamic characteristics of the porcine pulmonary valve and root with regard to the Ross procedure

Objective: The hydrodynamic parameters and leaflet motion of the porcine pulmonary root and valve and the performance of the pulmonary autograft implanted in subcoronary position or as a free-standing root were investigated at systemic and pulmonary pressures in vitro. Methods: Ten fresh pulmonary and aortic roots (anulus diameter, 20-25 mm) were tested in a pulsatile flow simulator. Five free-sewn pulmonary valves were implanted in aortic roots in the subcoronary position, and 5 pulmonary roots were implanted as free-standing roots. The external diameter of the roots was measured at the sinotubular junction in a pressure range of 0 to 120 mm Hg. The transvalvular gradient and regurgitation were measured, and the effective orifice area was calculated. The leaflet motion was recorded on video tape. Results: The fresh pulmonary roots were more compliant than their aortic counterparts (33% ± 3.0% vs 7% ± 1.5% with dilatation at 0-30 mm Hg and 46% ± 8.4% vs 35% ± 7.8% with dilatation at 0-120 mm Hg). The pulmonary roots had a lower pressure drop at systemic than at pulmonary pressures. The pressure drops of the pulmonary roots were also lower than those of the aortic roots in the systemic pressure range. The leaflet opening of the pulmonary valve was triangular, with low bending deformation at all pressures. Implanting the free-sewn pulmonary valve in the subcoronary position or the pulmonary root as a free-standing root did not affect the hydrodynamic parameters and leaflet motion adversely. Conclusion: The pulmonary valve and root could easily withstand aortic pressures in vitro. A biphasic dilatation curve ensures that higher pressures did not overdilate the pulmonary root. Moreover, valve performance was better at systemic pressures. (J Thorac Cardiovasc Surg 2000;120:284-9)

Size and distensibility of the aortic root and aortic valve function after different techniques of the Ross procedure

Objectives: In the Ross procedure, 3 different techniques are used for aortic valve replacement with the pulmonary autograft: freestanding root, inclusion, and subcoronary implantation. The objective of this study was to evaluate echocardiographically the influence of the particular operative technique on dimension, distensibility, and valve function. Methods: Between February 1990 and August 1998, the Ross procedure was performed in 111 patients (mean age, 48.6 ± 14.1 years; range, 15.2-70.6 years), with 1 early and 1 late death, 1 autograft replacement, and 1 patient lost to follow-up. The remaining patients underwent the freestanding root (n = 9 patients), inclusion (n = 14 patients), and subcoronary techniques (n = 84 patients). Echocardiography was performed at a mean follow-up of 26 ± 21.3 months after operation and was compared with the echocardiographic findings of the control subjects (n = 10 subjects). Root sizes were measured at the level of the anulus, sinus, and supra-aortic ridge; the distensibility was calculated as pressure strain elastic modulus and percent change of radius. Results: Size and distensibility of the aortic root were normal, except for a larger diameter at the sinus level in the root technique in comparison to the subcoronary technique ( P < .05; maximum diameter, 41.3 ± 8.6 mm vs 32.6 ± 4.0 mm). Aortic valve function was comparable among groups with low pressure gradients and most patients with no or trace aortic insufficiency. Conclusions: The freestanding root, inclusion, and subcoronary techniques in the Ross procedure provide comparable excellent hemodynamics, normal root size, and distensibility, except for the enlarged sinus diameter in the freestanding root. These results may have some impact on the operative procedure and follow-up investigations. (J Thorac Cardiovasc Surg 2000;119:990-7)

Pulmonary autograft procedure for aortic valve disease: long-term results of the pioneer series.

Pulmonary autograft replacement of the diseased aortic valve has not been widely practiced due to concerns regarding late autograft competence and the consequences of creating pulmonary valve disease. To investigate this, the fate of the pioneering series of patients has been determined. The 131 hospital survivors of the pulmonary autograft operation at the National Heart Hospital from 1967 to 1984 were identified and their outcomes determined to 1994. Age at operation was 11 to 52 years, and 109 patients were male. Autograft implantation was orthotopic subcoronary (107), free-standing root (20), or Dacron mounted (2). In 113 patients, homografts replaced the native pulmonary valve. Ten and 20 years after operation, survival was 85% and 61%, freedom from autograft replacement was 88% and 75%, and freedom from replacement of pulmonary position homografts was 89% and 80%, respectively. Causes of deaths (53) included chronic heart failure (13), complications of reoperation (12), and endocarditis (7). Autograft regurgitation, the most common indication for reoperation, appeared primarily technical in nature, usually due to cusp prolapse. Degeneration was found in only 3 of 30 explanted autografts, and the young patients showed no increase in late valve failure. Homografts outperformed other valve replacements in the pulmonary position, but patients with orthotopic subcoronary and root autografts survived similarly. The pulmonary autograft offers low rates of degeneration, endocarditis, and thromboembolism for a period lasting >20 years, particularly in the young, with reoperation mainly required for malpositioning of the autograft cusps. The capacity of the autograft to maintain viability with minimal degeneration is not matched by any other biological valve replacement.

Emergency surgery for acute infective aortic valve endocarditis: performance of cryopreserved homografts and mode of failure.

To describe our experience in the surgical treatment of infective, native and prosthetic aortic valve endocarditis, using cryopreserved homograft valves. Between January 1988 and September 1995, cryopreserved homografts were implanted in 49 patients (mean age 47 +/- 15 years; range 19-79) with acute infective endocarditis of the native (21/49; 43%) or the prosthetic (28/49; 57%) aortic valve. Aortic root abscesses were found in 39/49 (80%) patients, ventriculo-aortic disconnection in 27/49 (55%). An intracardiac fistula, originating from the left ventricular outflow tract was found in 25/49 (51%) patients. Indications for emergency surgery were congestive heart failure due to severe aortic valve regurgitation in 44/49 (90%) and systemic emboli in 5/49 (10%) patients. Preoperatively, 23/49 (47%) patients were in New York Heart Association (NYHA) class IV, and 5/49 (10%) were in acute circulatory failure. Mean left ventricular ejection fraction was 53 +/- 10% (25-65). Streptococci (27%) and staphylococci (27%) were the most important microorganisms found. The homograft was implanted as a scalloped freehand valve (34/49; 70%), as an intra-aortic inclusion cylinder (4/49; 6%) or as a free-standing root replacement (12/49; 24%). Combined procedures were necessary in 11/49 (22.5%) patients. Hospital mortality was 8.2% (4/49): 2/49 (4.1%) patients died from endocarditis-related sepsis, one (2%) from low cardiac output and one (2%) from a cerebrovascular accident. After a mean interval of 21 +/- 15 months (2-48), 9/45 (20%) patients had to be reoperated, all reoperations except one being homograft related. After a mean follow-up of 35 +/- 22 months (2-90), 4/44 (9%) patients had their homograft replaced by a mechanical prosthesis. After 5 years, actuarial freedom from late death was 97 +/- 3%; from late reoperation 69 +/- 9%; from late endocarditis 85 +/- 8%; and from late homograft degeneration 87 +/- 6%. Explanted homografts were acellular and non-vital, containing bacteria and/or leucocytes. B-lymphocytes were found in all and in one, T-cell lymphocytes were present. Emergency aortic valve replacement with cryopreserved homografts for acute native or prosthetic aortic valve endocarditis has a low operative mortality. The late incidence of recurrent endocarditis or homograft failure up to 7 years is acceptable. Cryopreserved homografts are non-viable. The presence of T-cell lymphocytes in explanted homografts indicates that rejection may be possible.