Is the Ross operation still an acceptable option in children and adolescents?

Biomechanics of Pulmonary Autograft as Living Tissue: A Systematic Review

Introduction: The choice of valve substitute for aortic valve surgery is tailored to the patient with specific indications and contraindications to consider. The use of an autologous pulmonary artery (PA) with a simultaneous homograft in the pulmonary position is called a Ross procedure. It permits somatic growth and the avoidance of lifelong anticoagulation. Concerns remain on the functionality of a pulmonary autograft in the aortic position when exposed to systemic pressure. Methods: A literature review was performed incorporating the following databases: Pub Med (1996 to present), Ovid Medline (1958 to present), and Ovid Embase (1982 to present), which was run on 1 January 2022 with the following targeted words: biomechanics of pulmonary autograft, biomechanics of Ross operation, aortic valve replacement and pulmonary autograph, aortic valve replacement and Ross procedure. To address the issues with heterogeneity, studies involving the pediatric cohort were also analyzed separately. The outcomes measured were early- and late-graft failure alongside mortality. Results: a total of 8468 patients were included based on 40 studies (7796 in pediatric cohort and young adult series and 672 in pediatric series). There was considerable experience accumulated by various institutions around the world. Late rates of biomechanical failure and mortality were low and comparable to the general population. The biomechanical properties of the PA were superior to other valve substitutes. Mathematical and finite element analysis studies have shown the potential stress-shielding effects of the PA root. Conclusion: The Ross procedure has excellent durability and longevity in clinical and biomechanical studies. The use of external reinforcements such as semi-resorbable scaffolds may further extend their longevity.

The effectiveness and safety of pulmonary autograft as living tissue in Ross procedure: a systematic review

BACKGROUND

Reports on effectiveness and safety after the implant of pulmonary autograft (PA) living tissue in Ross procedure, to treat both congenital and acquired disease of the aortic valve and left ventricular outflow tract (LVOT), show variable durability results. We undertake a quantitative systematic review of evidence on outcome after the Ross procedure with the aim to improve insight into outcome and potential determinants.

METHODS

A systematic search of reports published from October 1979 to January 2021 was conducted (PubMed, Ovid Medline, Ovid Embase and Cochrane library) reporting outcomes after the Ross procedure in patients with diseased aortic valve with or without LVOT. Inclusion criteria were observational studies reporting on mortality and/or morbidity after autograft aortic valve or root replacement, completeness of follow-up >90%, and study size n≥30. Forty articles meeting the inclusion criteria were allocated to two categories: pediatric patient series and young adult patient series. Results were tabulated for a clearer presentation.

RESULTS

A total of 342 studies were evaluated of which forty studies were included in the final analysis as per the eligibility criteria. A total of 8,468 patients were included (7,796 in pediatric cohort and young adult series and 672 in pediatric series). Late mortality rates were remarkably low alongside similar age-matched mortality with the general population in young adults. There were differences in implantation techniques as regard the variability in stress and the somatic growth that recorded conflicting outcomes regarding the miniroot vs the subcoronary approach.

DISCUSSION

The adaptability of lung autograft to allow for both stress variability and somatic growth make it an ideal conduit for Ross's operation. The use of the miniroot technique over subcoronary implantation for better adaptability to withstand varying degrees of stress is perhaps more applicable to different patient subgroups.

The Ross procedure in children: a systematic review

Background

The Ross procedure involves autograft transplantation of the native pulmonary valve into the aortic position and reconstruction of the right ventricular outflow tract (RVOT) with a homograft. The operation offers the advantages of a native valve with excellent hemodynamic performance, the avoidance of anticoagulation, and growth potential. Conversely, the operation is technically demanding and imposes the risk of turning single-valve disease into double-valve disease. This systematic review reports outcomes of pediatric patients undergoing the Ross procedure.

Methods

An electronic search identified studies reporting outcomes on pediatric patients (mean age <18 years, max age <21 years) undergoing the Ross procedure. Long-term outcomes, including early mortality, late mortality, sudden unexpected unexplained death, reoperation due to failure of the pulmonary autograft or RVOT reconstruction, thromboembolic events, bleeding events, and endocarditis-related complications, were evaluated.

Results

Upon review of 2,035 publications, 30 studies and 3,156 pediatric patients were included. Patients had a median age of 9.5 years and median follow-up period of 5.7 years. Early mortality rates varied from 0.0 to 17.0% and were increased in the neonatal population. Late mortality rates were much lower (0.04-1.83%/year). Reoperation due to pulmonary autograft failure occurred at rates of 0.37-2.81%/year and reoperation due to RVOT reconstruction failure was required at rates of 0.34-4.76%/year. Thromboembolic, bleeding, and endocarditis events were reported to occur at rates of 0.00-0.58, 0.00-0.39, and 0.00-1.68%/year, respectively.

Conclusions

The Ross operation offers a durable aortic valve replacement (AVR) option in the pediatric population that offers favorable survival, excellent hemodynamics, growth potential, decreased risk of complications, and avoidance of anticoagulation. Larger multi-institutional registries focusing on pediatric patients are necessary to provide more robust evidence to further support use of the Ross procedure in this population.

How Long Can the Next Intervention Be Delayed after Balloon Dilatation of Homograft in the Pulmonary Position?

Background and Objectives

We investigated the effectiveness of balloon dilatation of homograft conduits in the pulmonary position in delaying surgical replacement.

Subjects and Methods

We reviewed the medical records of patients who underwent balloon dilatation of their homograft in the pulmonary position from 2001 to 2015. The pressure gradient and ratio of right ventricular pressure were measured before and after the procedure. The primary goal of this study was to evaluate the parameters associated with the interval to next surgical or catheter intervention.

Results

Twenty-eight balloon dilations were performed in 26 patients. The median ages of patients with homograft insertion and balloon dilatation were 20.3 months and 4.5 years, respectively. The origins of the homografts were the aorta (53.6%), pulmonary artery (32.1%), and femoral vein (14.3%). The median interval after conduit implantation was 26.7 months. The mean ratio of balloon to graft size was 0.87. The pressure gradient through the homograft and the ratio of right ventricle to aorta pressure were significantly improved after balloon dilatation (p<0.001). There were no adverse events during the procedure with the exception of one case of balloon rupture. The median interval to next intervention was 12.9 months. The median interval of freedom from re-intervention was 16.6 months. Cox proportional hazards analysis revealed that the interval of freedom from re-intervention differed only according to origin of the homograft (p=0.032), with the pulmonary artery having the longest interval of freedom from re-intervention (p=0.043).

Conclusion

Balloon dilatation of homografts in the pulmonary position can be safely performed, and homografts of the pulmonary artery are associated with a longer interval to re-intervention.

The Ross Operation in Adolescents

Purpose:

The pulmonary autograft aortic valve replacement (Ross AVR) is the AVR of choice for children below the teenage years. Recent literature has questioned the durability of the Ross AVR in older children and young adults that present predominantly with aortic regurgitation and a dilated aortic root. At our center, the Ross AVR has been an excellent choice for most children and young and middle-aged adults. The Ross AVR is an especially good choice in young females who plan on becoming pregnant. We reviewed our experience with the Ross AVR in older children and young adults (10-20 years old) and analyzed mortality, early and late complications, and the need for reoperation and compared it to non-Ross AVR patients of the same age group during the same time period.

Methods:

Between 1993 and 2013, 79 children and young adults, of which 19 were female, between the age of 10 and 20, mean of 16.0 ± 2.7 years, underwent the Ross AVR. Follow-up ranged from 1 month to 20 years with a mean of 6.9 ± 5.8 years. Patients with primary and/or predominant aortic regurgitation and a dilated aortic root and/or ascending aorta at any level were called the “primarily aortic insufficiency (AI) group” (PAIG); 38 (48%) met this criteria. Because we saw some pathologic root enlargement and/or progressive aortic regurgitation in our early Ross experience (1993-2000), we modified our technique and postoperative management in 2000; 51 (65%) of 79 patients underwent the modified technique while 28 underwent our original Ross root replacement technique. The modified technique included reinforcing the aortic valve annulus and sinotubular junction and resecting or replacing the ascending aorta if it was dilated (>30 mm). Twenty-six patients during this same time period and in the same age group underwent the non-Ross AVR with a mean age of 16.5 ± 2 years. Seven of these 26 non-Ross patients were female, and 16 (62%) presented with aortic regurgitation as their primary lesion.

Results:

The early mortality for the Ross group and the non-Ross group was 0% and 4%, respectively. Late mortality for the Ross group was 2.5% and 0% for the non-Ross group. Of the 28 patients, 14 (50%) receiving the early Ross operation prior to 2000 have required reoperations. Only three (5.9%) of the 51 patients done after 2000 have required surgical reintervention ( P <.01). In all, 11 (34%) of our Ross patients operated prior to 2000 and three (6%) after 2000 have required reintervention on their autografts. Patients in the PAIG had zero early and late deaths and a 16% rate of reoperation on the autograft compared to zero early and two late deaths and 20% rate of reoperation in patients not in the PAIG group ( P = .266 and .467 respectively). The actuarial survival for the Ross group at 5 (N = 42), 10 (N = 24), and 20 (N = 1) years was 100%, 97%, and 73% respectively. Survival for the non-Ross group at 5 (N = 18), 10 (N = 8), and 20 (N = 1) years was 96%, 96%, and 96%, respectively; this difference in survival was not statistically significant ( P =.90). Differences in survival without reoperation for both the groups were not statistically significant ( P =.55). When comparing patients who had the newer Ross AVR technique and the non-Ross AVR patients, there was a significantly lower incidence of late aortic stenosis (AS) with a resting gradient greater than 20 mm Hg, 0% versus 53% ( P <.001).

Conclusion:

The Ross AVR is the procedure of choice for adolescents requiring AVR who have a normal pulmonary valve. There was no difference between the outcomes in patients who were in the PAIG group compared to non-PAIG patients. There was no difference in survival without reoperation between the Ross AVR and the non-Ross AVR within the 10- to 20-year age group. The Ross AVR patients had lower incidences of nonoperative complications. The Ross AVR patients had excellent hemodynamic outcomes with a significantly lower incidence of late AS when compared to the non-Ross AVR group. Reports of 15- to 20-year survival for the Ross AVR are encouraging. Long-term follow-up is necessary in all patients with aortic valve disease regardless of the treatment modality.

Rethinking the ross procedure in adults

BACKGROUND

Although questionable durability has tempered enthusiasm for the Ross procedure in the last decade, the perioperative risks of the Ross procedure relative to conventional aortic valve replacement are not well described. The goal of this study is to describe both the perioperative outcomes and utilization trends of the Ross procedure in adults in The Society of Thoracic Surgeons Adult Cardiac Surgery Database.

METHODS

The Society of Thoracic Surgeons Adult Cardiac Surgery Database was used to review all Ross procedures performed between 1994 and 2010. The utilization of the procedure in the database was assessed. Then the preoperative comorbidities, patient demographics, and risk factors were reviewed, as were intraoperative and perioperative outcomes.

RESULTS

Of 648,541 aortic valve replacements during the study period, 3,054 (0.47%) were identified as Ross procedures. Utilization of the procedures as a percent of total aortic valve replacements peaked in 1998 at 1.2%, followed by a steady decline to 0.09% by 2010. More than a quarter of all Ross operations were performed at six sites. Using propensity-matching analyses, Ross patients experienced significantly more perioperative complications including reexploration (9.4% versus 5.8%; p < 0.01), renal failure (2.6% versus 0.8%; p < 0.001), and operative mortality (2.7% versus 0.9%; p = 0.001).

CONCLUSIONS

These data suggest that the Ross procedure is associated with greater perioperative morbidity and mortality risks compared with conventional aortic valve replacement. Recognition of these risks along with durability concerns have resulted in a dramatic decline in the number of Ross procedures performed in North America in the last decade.

Mechanism of autograft insufficiency after the Ross operation in children

BACKGROUND

It is unclear how autografts grow and dilate after the Ross operation in children. We analysed autograft growth and dilatation in children who underwent the Ross operation and examined the relationship of these factors to autograft failure.

METHODS

From our institutional database, we retrospectively identified 33 children who underwent the Ross operation without aortic root reinforcement (mean age 9.9 years) and had normal body measurements and echocardiographic data throughout follow-up.

RESULTS

Autograft insufficiency developed in 10 patients 5.1 years after the Ross operation. The average Z score at the development of autograft insufficiency was -0.1 (range from -2.0 to 6.1). The proportions of patients who remained free of autograft insufficiency at 5 and 10 years were 87.2% and 55.7%, respectively. A consistent trend in the time course of Z score was not found in any age group studied.

CONCLUSIONS

Autograft growth and dilation after the Ross operation varied widely among patients, and the incidence of autograft insufficiency was independent of annulus size.

Exercise stress echocardiography after childhood Ross surgery: functional outcome in 26 patients from a single institution

Adult studies suggest a better functional outcome after aortic valve replacement with a pulmonary autograft compared with mechanical or homograft valves. Little is known about functional results after Ross surgery in growing children. This study reports formal exercise stress echocardiographic data from 26 pediatric Ross patients. A retrospective cohort study analyzed stress echocardiographic data of patients who underwent Ross surgery as a child (<17 years old). All patients were operated by a single surgeon and underwent a Bruce protocol stress echocardiogram on the treadmill. Twenty-six patients (4 girls) were 9.3 ± 5.0 years at surgery and 14.9 ± 3.5 years (range 6.6-19.7 years) at follow-up. Mean follow-up was 5.4 ± 3.7 years (median 4.2). All were asymptomatic. The exercise time was normal in 87% of cases at 12.8 ± 2.5 min. On stress echocardiography, the mean right-ventricular outflow tract (RVOT) gradient increased from 38 ± 22 mmHg at rest to 82 ± 33 mmHg after exercise, but this did not correlate with exercise times. Stress echocardiography is useful in evaluating patients after childhood Ross surgery for aortic valve disease. In this pediatric cohort, most patients achieved normal exercise capacity. The presence of mild or moderate RVOT obstruction had no significant impact on exercise capacity.

Managing arrhythmias before and after aortic valve surgery in children

The proximity of the coronary arteries and the bundle of His to the aortic valve may contribute to the pathogenesis of arrhythmias in patients with aortic valve disease. Severe aortic valve disease may also adversely alter left ventricular hemodynamics (end-diastolic dimensions and wall stress) and thus create a substrate for ventricular arrhythmias before any intervention is performed. The severity of these arrhythmias depends on the severity of the underlying substrate (or the specific problem, such as aortic stenosis or aortic regurgitation), the age at which the aortic valve intervention was performed, the type of intervention (i.e. transcatheter aortic valve interventions or open aortic valve replacement or repair), and the reversibility of the altered hemodynamics after surgery. Both bradyarrhythmias and tachyarrhythmias are known complications of aortic valve interventions. Although data are scant, this review summarizes the incidence of arrhythmias before and after aortic valve interventions from a pediatric perspective.

Effective transcatheter valve implantation after pulmonary homograft failure: a new perspective on the Ross operation

Objective

The Ross procedure offers good autograft function and low reoperation rates for the neoaortic valve; however, the rate of conduit dysfunction in the right ventricular outflow tract remains a concern. This study assessed percutaneous pulmonary valve implantation in this setting.

Methods

We retrospectively analyzed outcomes of 12 patients (mean age 28 ± 5 years) referred for percutaneous pulmonary valve implantation to treat right ventricle–pulmonary artery conduit failure 11.1 ± 3.3 years after Ross procedure.

Results

Percutaneous pulmonary valve implantation was feasible in all 12 patients, with no procedural complications (procedure time 99 ± 16 minutes, fluoroscopy time 21 ± 6 minutes). Right ventricular outflow tract gradient during catheterization and pulmonary regurgitant fraction on magnetic resonance imaging fell after valve implantation (gradient 34 ± 6 to 14 ± 3 mm Hg, P < .01, regurgitant fraction 20% ± 6% to 2% ± 1%, P < .05). After restoration of right ventricular outflow tract function, indexed right ventricular end-diastolic volume decreased (91 ± 13 to 78 ± 12 mL · beat⁻¹ · m⁻², P < .01) and maximal cardiopulmonary exercise performance improved (peak oxygen consumption 25.4 ± 2.3 to 30.8 ± 3.0 mL · kg⁻¹ · min⁻¹, P < .01). During follow-up (18.8 ± 4.6 months), there was 1 device explantation (restenosis). The probabilities of freedom from right ventricular outflow tract reoperation were 100% at 1 year and 90% at 3 years.

Conclusions

Percutaneous pulmonary valve implantation provides an effective transcatheter treatment strategy to prolong the lifespan of right ventricle–pulmonary artery conduits after the Ross procedure, reducing the reoperation burden on patients with aortic valve disease.

The Ross Procedure

Background— Reports on outcome after the Ross procedure are limited by small study size and show variable durability results. A systematic review of evidence on outcome after the Ross procedure may improve insight into outcome and potential determinants.

Methods and Results— A systematic review of reports published from January 2000 to January 2008 on outcome after the Ross procedure was undertaken. Thirty-nine articles meeting the inclusion criteria were allocated to 3 categories: (1) consecutive series, (2) adult patient series, and (3) pediatric patient series. With the use of an inverse variance approach, pooled morbidity and mortality rates were obtained. Pooled early mortality for consecutive, adult, and pediatric patients series was 3.0% (95% confidence interval [CI], 1.8 to 4.9), 3.2% (95% CI, 1.5 to 6.6), and 4.2% (95% CI, 1.4 to 11.5). Autograft deterioration rates were 1.15% (95% CI, 1.06 to 2.06), 0.78% (95% CI, 0.43 to 1.40), and 1.38%/patient-year (95% CI, 0.68 to 2.80), respectively, and for right ventricular outflow tract conduit were 0.91% (95% CI, 0.56 to 1.47), 0.55% (95% CI, 0.26 to 1.17), and 1.60%/patient-year (95% CI, 0.84 to 3.05), respectively. For studies with mean patient age >18 years versus mean patient age ≤18 years, pooled autograft and right ventricular outflow tract deterioration rates were 1.14% (95% CI, 0.83 to 1.57) versus 1.69% (95% CI, 1.02 to 2.79) and 0.65% (95% CI, 0.41 to 1.02) versus 1.66%/patient-year (95% CI, 0.98 to 2.82), respectively.

Conclusions— The Ross procedure provides satisfactory results for both children and young adults. Durability limitations become apparent by the end of the first postoperative decade, in particular in younger patients.