Left ventricular retraining in corrected transposition: Relationship between pressure and mass

Echocardiographic Predictors of Readiness for Double Switch Operation and Postoperative Ejection Fraction in Patients With Congenitally Corrected Transposition of the Great Arteries Undergoing Left Ventricular Retraining

BACKGROUND

In patients with congenitally corrected transposition of the great arteries (ccTGA), assessment of readiness for the double switch operation (DSO) after pulmonary arterial band (PAB) placement involves cardiac magnetic resonance imaging (cMRI) to measure left ventricular ejection fraction (LVEF) and mass and cardiac catheterization (catheterization) to assess the ratio of left ventricular to right ventricular pressure (LV:RVp). The aims of this study were to describe the relationships between echocardiographic and catheterization and cMRI measures of readiness for DSO and to develop risk factors for left ventricular (LV) dysfunction after DSO on the basis of echocardiographic measures of ventricular-arterial coupling (VAC).

METHODS

Patients with ccTGA undergoing LV retraining at a DSO referral center were reviewed. LVEF measured by echocardiography was compared with that measured by cMRI, and LV:RVp measured by echocardiography was compared with that measured by catheterization using Bland-Altman analysis. The relationship between preoperative VAC markers and postoperative echocardiography was analyzed using ventricular end-systolic elastance (EES) and a novel marker consisting of the product of LVEF and LV:RVp (EFPR).

RESULTS

Thirty-one patients with 56 evaluations for DSO were included, 24 of whom underwent DSO. Echocardiographic LVEF correlated well with cMRI LVEF (r = 0.79), and Bland-Altman analysis slightly overestimated cMRI LVEF (mean difference, +3%). Echocardiographic LVEF had a moderate ability to identify normal cMRI LVEF (area under the curve, 0.80) and at an optimal cut point of echocardiographic LVEF threshold of 61%, there was 71% sensitivity and 76% specificity to detect cMRI LVEF ≥ 55%. Echocardiographic LV:RVp correlated well with LV/RVp by catheterization (r = 0.77) and slightly underestimated the catheterization value (mean difference, -0.11). Echocardiographic LV:RVp had a good ability to identify adequate LV:RVp by catheterization (area under the curve, 0.95) and at an optimal echocardiography cut point of 0.75 had 100% sensitivity and 85% specificity to detect a catheterization LV:RVp >0.9. Echocardiography-based criteria for DSO readiness (echocardiographic LVEF of 61% and LV:RVp of 0.75) demonstrated specificity of 97% and positive predictive value of 96% for published criteria of DSO readiness (cMRI LVEF of 55% and catheterization LV:RVp of 0.9). EES and EFPR correlated with post-DSO LVEF (ρ = 0.72 and ρ = 0.60, respectively). EFPR of 0.51 demonstrated 78% sensitivity and 100% specificity for post-DSO LV dysfunction (LVEF < 55%). Age at first PAB also strongly correlated with post-DSO LVEF (ρ = 0.75). No patient with first PAB at <1 year of age exhibited post-DSO LV dysfunction.

CONCLUSIONS

Echocardiographic measures of LVEF and LV:RVp are reliable indicators of reference standard modalities and can guide management during retraining. The preoperative VAC markers EES and EFPR may be useful markers of post-DSO LV dysfunction. Values of echocardiographic LV:RVp >0.75 are likely to meet pressure-generation criteria for DSO and should be considered for referral to catheterization and cMRI evaluation for DSO. PAB placement before 1 year of life may optimize LV outcomes in patients considered for DSO.

Results of the Double Switch Operation in Patients Who Previously Underwent Left Ventricular Retraining

BACKGROUND

Congenitally corrected transposition of the great arteries (CC-TGA) is a complex form of congenital heart disease that has numerous subtypes. While most patients with CC-TGA have a large ventricular septal defect (VSD) and pulmonary stenosis, there are some patients who have either no VSD or a highly restrictive VSD. These patients will require left ventricular (LV) retraining prior to double switch. The purpose of this study was to review our experience with the double switch procedure in patients who had previously undergone LV retraining.

METHODS

This was a retrospective review of a single institution experience with the double switch procedure in patients who had undergone LV retraining (2002-present).

RESULTS

Forty-five patients underwent double switch following LV retraining. Of these, 39 had an arterial switch with hemi-Mustard/bidirectional Glenn and six had a Senning. The median cross-clamp time was 135 min (range 71-272) and median bypass time was 202 min (range 140-430 min). Median hospital length of stay was eight days (range 4-108). There were no in-hospital deaths. Median duration of follow-up was 30 months (range 0-175). One patient subsequently underwent heart transplantation and died 65 months following double switch. At follow-up, 41 of the 44 survivors (93%) have normal or low normal LV function and 40 of the 44 survivors (91%) have no or trace mitral regurgitation.

CONCLUSIONS

The data demonstrate early and mid-term survival of 100% and 97%. Ninety-three percent had preserved LV function. These results suggest that patients with CC-TGA who undergo LV retraining and double switch can have excellent clinical outcomes.

Management Options for Congenitally Corrected Transposition: Which, When, and for Whom?

Management strategies for congenitally corrected transposition of the great arteries (ccTGA) historically consisted of a physiologic repair, resulting in the morphologic right ventricle (mRV) supporting systemic circulation. This strategy persisted despite the development of heart failure by middle age because of the reasonable short-term outcomes, and the natural history of some patients with favorable anatomy (felt to demonstrate the mRV's ability to function in the long-term), and due to the less-than-optimal outcomes associated with anatomical repair. As outcomes with anatomical repair improved, and the long-term risk of systemic mRV dysfunction became apparent, more have begun to realize its advantages. In addition to the decision on whether or not to pursue anatomical repair, and the optimal timing, studies demonstrating the nuance to morphologic left ventricle retraining have demonstrated its feasibility. Further considerations in ccTGA have begun to be better understood, including: the management of a poorly functioning mRV, systemic tricuspid valve regurgitation, the utility of morphologic left ventricle outflow tract obstruction (native or surgically created) and pacing strategies. While some considerations are apparent: biventricular pacing is superior to univentricular, tricuspid regurgitation must be managed early with either progression towards anatomical repair (pulmonary artery banding if needed for retraining) or tricuspid replacement (not repair) based on the patient's age; others remain to be completely elucidated. Overall, the heterogeneity of ccTGA, as well as the unique presentation with each patient regarding ventricular and valvular function and center-to-center variability in management strategies has made the interpretation of published data difficult. That said, more recent long-term outcomes favor anatomical repair in most situations.

Contemporary outcomes of the double switch operation for congenitally corrected transposition of the great arteries

OBJECTIVE

To determine the contemporary outcomes of the double switch operation (DSO) (ie, Mustard or Senning + arterial switch).

METHODS

A single-institution, retrospective review of all patients with congenitally corrected transposition of the great arteries undergoing a DSO.

RESULTS

Between 1999 and 2019, 103 patients underwent DSO with a Mustard (n = 93) or Senning (n = 10) procedure. Segmental anatomy was (S, L, L) in 93 patients and (I, D, D) in 6 patients. Eight patients had heterotaxy and 71 patients had a ventricular septal defect. Median age was 2.1 years (range, 1.8 months-40 years), including 34 patients younger than age 1 year (33%). Median weight was 10.9 kg (range, 3.4-64 kg). Sixty-one patients had prior pulmonary artery bands for a median of 1.1 years (range, 14 days-12.9 years; interquartile range, 0.7-3.1 years). Median intensive care unit and hospital lengths of stay were 5 and 10 days, respectively. Median follow-up was 3.4 years (interquartile range, 1-9.8 years) and 5.2 years (interquartile range, 2.3-10.7 years) in 79 patients with >1 year follow-up. At latest follow-up, aortic, mitral, tricuspid valve regurgitation, and left ventricle dysfunction was less than moderate in 96%, 98%, 96%, and 93%, respectively. Seventeen patients underwent reoperation: neoaortic valve intervention (n = 10), baffle revision (n = 5), and ventricular septal defect closure (n = 4). At latest follow-up, 17 patients (17%) had a pacemaker and 27 (26%) had cardiac resynchronization therapy devices. There were 2 deaths and 2 transplants. Transplant-free survival was 94.6% at 5 years. Risk factors for death or transplant included longer cardiopulmonary bypass time and older age at DSO.

CONCLUSIONS

The outcomes of the DSO are promising. Earlier age at operation might favor better outcomes. Progressive neoaortic regurgitation and reinterventions on the neo-aortic valve are anticipated problems.

Outcomes of treatment pathways in 240 patients with congenitally corrected transposition of great arteries

OBJECTIVE

Congenitally corrected transposition of the great arteries (ccTGA) encompasses a diverse morphologic cohort, for which multiple treatment pathways exist. Understanding surgical outcomes among various pathways and their determinants are challenged by limited sample size and follow-up, and heterogeneity. We sought to investigate these questions with a large cohort of ccTGA patients presenting at different ages and representing the full therapeutic spectrum.

METHODS

Retrospective review of 240 patients diagnosed with ccTGA from Cleveland Clinic coupled with prospective cross-sectional follow-up. Forty-six patients whose definitive procedure was completed elsewhere were excluded. Time-related survival was described among treatment pathways using actuarial, time-varying covariate, and competing risks analyses. Temporal trends in longitudinal valve and ventricular function were assessed using nonlinear mixed-effects models.

RESULTS

Median follow-up was 10 years. Seventy-nine patients with ccTGA underwent anatomic repair, 45 physiologic repair, 24 Fontan palliation, and 6 primary transplant. Forty patients managed expectantly had excellent long-term survival when considered from time of presentation, but benefited from failures captured following transition to physiologic repair or transplant. Morphologic right ventricular dysfunction after physiologic repair increased from 68% to 85% after 5 years, whereas morphologic left ventricular function was stable in anatomic repair, especially with early surgery. Transplant-free survival at 15 years for anatomic and physiologic repair was 80% and 71%, respectively.

CONCLUSIONS

Early anatomic repair may be preferable to physiologic repair for select ccTGA patients. Late attrition after physiologic repair represents failure of expectant management and progressive tricuspid valve and morphologic right ventricular dysfunction compared with anatomic repair, where morphologic left ventricular function is relatively preserved.