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Cone reconstruction for Ebstein anomaly

Aug. 03, 2019

Ebstein anomaly (EA) is a rare, complex and highly variable congenital heart malformation characterized by tricuspid valve regurgitation, right ventricle myopathy. Management can be challenging because EA presents with a broad clinical spectrum of variable anatomy and symptoms affecting a wide demographic, from neonates who are highly symptomatic, to adults who are asymptomatic. Most patients with EA require surgical management at some point in life.

In 1972, Gordon K. Danielson, M.D., a cardiovascular surgeon at Mayo Clinic, was the first to provide a durable tricuspid valve repair for EA. In 1979, Dr. Danielson's landmark paper published in Mayo Clinic Proceedings set the course for Mayo's leadership in EA management, according to Joseph A. Dearani, M.D., chair of Cardiovascular Surgery at Mayo Clinic in Rochester, Minnesota.

Dr. Dearani trained with Dr. Danielson, and later studied with another pioneer in novel techniques, José Pedro da Silva, M.D., who developed the cone reconstruction (CR) in the early 1990s. The CR has been modified by Dr. Dearani and is a desirable approach because it achieves near anatomic leaflet union and function of the tricuspid valve through extensive leaflet mobilization, longitudinal plication of the atrialized ventricle and cone-shaped reconstruction of the tricuspid valve. This allows for leaflet-to-leaflet coaptation. Most importantly, the CR is performed at the true anatomic valve annulus, thereby recruiting functional right ventricle below the level of leaflet coaptation.

Refining the CR technique

The Mayo team continues to modify and refine the CR approach and has gained surgical experience treating more than 350 patients. Mayo Clinic's total population of patients with EA — medical, surgical and postoperative cohorts — exceeds 1,300 patients.

Says Dr. Dearani: "Because EA is so rare — it accounts for less than 1% of congenital heart defects — few centers amass the critical expertise and significant outcome data that Mayo has developed to reproduce or standardize results. These outcome data are crucial to support evidence-based decision-making on how clinical teams should best manage EA patients."

From 2007 to 2019, Mayo Clinic cardiovascular surgery teams published a series of reports documenting advances in the care and outcomes of CR for patients with EA. "Our experience shows that cone reconstruction has become the standard of care for Ebstein anomaly and has excellent outcomes," explains Mayo's Frank Cetta Jr., M.D., a specialist in congenital heart defects in both children and adults at Mayo Clinic's campus in Minnesota. Highlights include:

2019: Quality of life after cone repair in children

In 2019, the Mayo Clinic pediatric cardiology and cardiovascular surgery team members reviewed records of all patients younger than 21 years old treated with CR from 2007 to 2016, and published their findings in Cardiology in the Young. They assessed quality of life across four domains: physical, emotional, social and school functioning. Of 116 eligible patients, 72 (62 percent) responded to the survey.

Results showed:

Approximately 96% of the patients reported their health as excellent or good.
52% of patients were symptom-free.
Only 37% of patients were taking any medications. The most common was aspirin (30%).
On average, the self-reported quality of life score for youth was 85.3 out of 100 and for parents or parent proxies, 81.8 out of 100.
Compared to healthy children who had not undergone CR, there was no difference by youth or parent proxy report in quality of life.
Quality of life was significantly better in youth after CR compared with children who had other chronic health conditions.

2018: Large-sample study fills data gaps

While CR has generated enthusiasm due to its anatomic restoration, it has limits. One limit is the surgical expertise and steep learning curve required to perform CR. Centers that do not treat high volumes of this rare condition typically lack the advanced skills and mentoring needed to master techniques. The other limit is a gap in the data. Both durability data and echocardiographic follow-up data have been lacking, thus impeding the assessment of the functional longevity of repairs.

From June 2007 and October 2015, Dr. Dearani reported on the Mayo experience with the first 235 consecutive patients undergoing the CR. Published in the 2018 Annals of Thoracic Surgery, the report shows 134 (57 %) were children and 101 were adults (43 %), with a median age of 15.6 years and a range from 6 months to 73 years.

Results showed:

Patients experienced sustained reduction in tricuspid regurgitation.
A progressive decline in the size of the right ventricle was achieved.
At six years, patients experienced 97.9% freedom from the need to re-operate.
There was low early mortality in the presence of advanced heart failure.

Says Dr. Dearani: "Our results show that CR is safe and has a positive impact on right ventricle remodeling over time. Those are powerful advantages in restoring patient quality of life."

2017: Global pediatric CR collaboration

Mayo Clinic has hosted more than 10 Russian heart specialists at the Rochester campus of Mayo Clinic in Minnesota and sent multiple pediatric cardiologists from Rochester on teaching and care missions throughout Russia. Mayo fellows and consultants have made more than 20 trips to Russia since 2004, collaborating with Heart to Heart International, a nonprofit global heart care aid group based in Oakland, California.

In a 2017 issue of the Texas Heart Institute Journal, Drs. Dearani and Cetta and their Russian colleagues published the results of a study on modified CR performed on four girls and two boys, ages 11 months to 12 years, in Siberia. All six patients survived the difficult surgery, and five of the six were discharged with excellent results. At four-year follow-up, all were free of arrhythmias, right side heart failure or tricuspid stenosis and experienced only mild regurgitation. The single patient who had CR failure had a challenging pathology and leaflet anatomy that led to the breakdown of the CR. Her tricuspid valve was replaced with a bioprosthesis.

2014: Mayo Clinic experience with cone repair in children

For pediatric patients, EA valve repair results have historically been varied. But Mayo Clinic's experience as a pioneer in EA repair, combined with its role as a leading center for medical, surgical and follow-up care for children and adults, have helped achieve uniformly positive EA valve repair results.

"Mayo was therefore uniquely positioned to review results of patients under 21 years of age (n = 84 patients) who underwent the cone reconstruction at Mayo Clinic from 2007 to 2012," Dr. Cetta explains.

Study results published in Congenital Heart Disease in 2014 showed:

98% of Mayo Clinic patients had successful CR and were discharged from the hospital with good results.
CR is an excellent option for children and young adults with Ebstein anomaly.
For most patients, undergoing CR avoids the need for valve replacement and can be performed with low early mortality.
Patients who underwent CR rarely required re-intervention at five-year follow-up.

Given the rapid progress in evolving techniques and durable CR outcomes, Drs. Dearani and Cetta continue to expect most patients with EA to thrive. Says Dr. Dearani: "EA is a fascinating condition because every abnormality is different from patient to patient. But our understanding of the condition and the cone reconstruction technique have advanced to the point that we can consistently tailor successful treatment to each individual."

Dr. Cetta adds: "The progress is remarkable. For example, with the advancement in untrasound technology, EA is a diagnosis that often is diagnosed prenatally so parents and surgical team are prepared for it at birth and can decide how to proceed. While timing of treatment can be quite variable, knowing what to expect from birth is key to meeting a patient's needs over the course of a lifetime. The main point is this: Almost all EA patients' valves can now be repaired, particularly by experienced CR surgeons."