Schaff, Hartzell V.

In patients with congenitally corrected transposition of the great arteries, the main concern has been the long-term performance of the morphologic right ventricle in association with tricuspid valve regurgitation when it remains as the systemic ventricle. Deterioration in ventricular function can occur slowly over many years, even without associated cardiac anomalies or previous surgical interventions. This review summarizes the authors' experience and provides a thorough review of the literature addressing the management of the failing systemic right ventricle as well as the tricuspid valve regurgitation with congenitally corrected transposition. This includes different surgical options, the authors' preferred management algorithm, and the late outcome.

Background— After repair of aortic coarctation, patients may develop restenosis, aneurysms, and pseudoaneurysms at the site of prior repair. We assessed the outcomes of late reintervention on the descending aorta after aortic coarctation repair. Methods and Results— From March 1954 to July 2008, 130 patients had operations or endovascular procedures on the descending aorta after previous coarctation repair. We excluded patients who had complex left-sided cardiac lesions or interrupted aortic arch. Mean age at reintervention was 32±24 years and 28% were female. The interval between coarctation repair and reintervention was 17±13 years. Seventy-four percent of patients had hypertension. Reasons for reintervention were restenosis (n=122 [94%]), aneurysm (n=4 [3%]), and pseudoaneurysm (n=4 [3%]). Ninety-five patients (73%) underwent operative procedures including an extra-anatomic conduit (n=41), patch repair (n=32), interposition graft (n=14), end–end anastomosis (n=6), and subclavian flap (n=2). Thirty-five patients underwent endovascular treatment (balloon dilatation, n=22 or stenting, n=13). There was no early mortality. In the surgical group, 5 patients required early reoperation for bleeding and 5 patients had early vocal cord paralysis. One patient in the endovascular group had aortic rupture at the time of intervention requiring urgent operation. Survival was 97% at 10 years. At 5 years, freedom from a second repeat procedure on the descending aorta was 96% in the surgical group and 72% in the endovascular group ( P <0.001). Five years after reintervention, fewer patients required treatment for hypertension (57% versus 74% , P <0.001) and a median of 1 antihypertensive medication was prescribed compared with a median of 2 medications preintervention. Conclusions— Operative and endovascular management of recoarctation can be performed safely with good late outcomes.

Background— Proposed advantages to the Ross procedure included presumed increased freedom from reoperation and simpler reoperation for pulmonary conduit replacement if needed. It is increasingly apparent, however, that reoperations are frequent after the Ross procedure and that when required, they may be more complex than previously thought. Methods and Results— Between September 1991 and August 2008, 56 patients underwent reoperation at our institution after a Ross procedure performed by ourselves (n=13) or elsewhere (n=43). Median age at first reoperation at our institution was 26 years (range 1 to 69 years). The 4 most common indications for reoperation were isolated autograft (neoaortic) regurgitation in 11 cases (20), isolated pulmonary conduit regurgitation/stenosis in 9 (16), combined autograft regurgitation/dilatation in 8 (14), and combined autograft regurgitation and pulmonary conduit regurgitation/stenosis in 6 (11). A total of 144 procedures were performed in these 56 patients during first reoperation at our institution. The autograft valve required replacement in 21 cases (38) and aortic root replacement in 21 (38), with ascending aortic/arch reconstruction in 13 (23) and mitral valve surgery in 5 (9). The pulmonary valve was replaced in 33 cases (59) and the tricuspid valve was repaired/replaced in 10 (18). Early mortality was 1.8 (1 of 56 patients), and morbidity included 6 patients with respiratory failure and 3 who required postcardiotomy extracorporeal membrane oxygenation. There were 4 late deaths during the median follow-up of 8 months (range 1 to 179 months). Conclusions— A broad spectrum of complex reoperations may be required after the Ross procedure. Patients and family members considering the procedure should be informed of the potential for associated morbidity should reoperation be necessary.

Irreparable mitral pathology may lead to early mitral valve replacement (MVR) in children. Often, a small mechanical prosthesis (<23 mm) is required, raising concerns about annular growth in patients who may eventually require subsequent mitral valve re-replacement (MVRR). The aim of this study was to evaluate interval mitral annular growth in this cohort. Between January 1972 and December 2006, 164 children underwent MVR with a mechanical prosthesis; 110 of these children (median age, 4 years; range, 7 days to 14 years) received a small mechanical prosthesis (<23 mm). The most common diagnoses were congenital mitral stenosis (10%), regurgitation (46%), and left atrioventricular valve dysfunction after previous atrioventricular septal defect repair (44%). The cohort was analyzed for age, body surface area (BSA), prosthesis size, and Z score at the time of MVR and MVRR. At the time of MVR, 78 patients had a BSA of 0.77 ± 0.06 m2, had an annular size of 24 ± 0.62 mm ( Z score, 2.91 ± 0.23), and ultimately did not require MVRR. Another cohort, who eventually did require MVRR (n = 24), had an initial BSA at the time of MVR of 0.62 ± 0.05 m2 ( P = NS vs MVR only) and an annular size of 20 ± 0.49 mm ( Z score, 1.85 ± 0.22) ( P = .008 vs MVR only). In the interval between MVR and MVRR (7.8 ± 1.1 years), BSA increased to 1.12 ± 0.07 m2, and annulus size increased to 24 ± 0.47 mm ( Z score, 1.80 ± 0.28). These data suggest growth of the mitral annulus following MVR with a small mechanical prosthesis, as evidenced by an unchanged Z score in the setting of normal interval increase in BSA. Additionally, there was a statistically significant difference in initial Z scores between the cohorts requiring MVRR and those who have not needed re-replacement, suggesting that the feasibility of placement of a slightly larger prosthesis may be associated with a decreased need for MVRR.

Background— Mitral annulus is a complex structure of poorly understood physiology. Full-volume real-time 3-dimensional transesophageal echocardiography offers a unique opportunity to completely image and quantify mitral annulus size and motion. Methods and Results— Real-time 3-dimensional transesophageal echocardiography of the mitral valve was acquired in 32 patients with myxomatous valve disease (MVD) and moderate to severe regurgitation, 15 normal control subjects, and 10 patients with ischemic mitral regurgitation of identical body surface area. Mitral annular dimensions (circumference, area, anteroposterior and intercommissural diameters, height, and ratio of height to intercommissural diameter ratio, which appraises annular saddle-shape depth) were measured throughout the cardiac cycle with dedicated quantification software. Compared with direct surgical measurement, 3-dimensional anterior annular dimension provided reliable measurements (mean difference, 0.1±0.1 mm; P =0.73; 95% confidence interval, ±4.4 mm). Annular dimensions were larger in MVD patients compared with control subjects in diastole (all P <0.05). Normal annulus displayed early-systolic anteroposterior ( P <0.001) and area ( P =0.04) contraction, increased height ( P <0.001), and deeper saddle shape (ratio of height to intercommissural diameter, 15±1% to 21±1%; P <0.001), whereas intercommissural diameter was unchanged ( P =0.30). In contrast, MVD showed early-systolic intercommissural dilatation ( P =0.02) and no area contraction ( P =0.99), height increase ( P =0.11), or saddle-shape deepening ( P =0.35). Late-systolic MVD annular saddle shape deepened but annular area excessively enlarged ( P <0.04) as a result of persistent intercommissural widening ( P <0.02). MVD annulus also contrasts with ischemic mitral regurgitation annulus, which, despite similar anteroposterior enlargement, is narrower and essentially adynamic. After MVD repair, the annulus remained dynamic without systolic saddle-shape accentuation ( P =0.30). Conclusions— Real-time 3-dimensional transesophageal echocardiography provides insights into normal, dynamic mitral annulus function with early-systolic area contraction and saddle-shape deepening contributing to mitral competency. MVD annulus is also dynamic but considerably different with loss of early-systolic area contraction and saddle-shape deepening despite similar magnitude of ventricular contraction, suggestive of ventricular-annular decoupling. Subsequent area enlargement may contribute to mitral incompetence. After mitral repair, MVD annulus remains dynamic without systolic saddle-shape accentuation. Thus, real-time 3-dimensional transesophageal echocardiography provides new insights that allow the refining of mitral pathophysiology concepts and repair strategies.

Background— Mutations in myofilament proteins, most commonly MYBPC3 -encoded myosin-binding protein C and MYH7 -encoded β-myosin heavy chain, can cause hypertrophic cardiomyopathy (HCM). Despite significant advances in structure-function relationships pertaining to the cardiac sarcomere, there is limited knowledge of how a mutation leads to clinical HCM. We, therefore, set out to study expression and localization of myofilament proteins in left ventricular tissue of patients with HCM. Methods and Results— Frozen surgical myectomy specimens from 47 patients with HCM were examined and genotyped for mutations involving 8 myofilament-encoding genes. Myofilament protein levels were quantified by Western blotting with localization graded from immunohistochemical staining of tissue sections. Overall, 25 of 47 (53%) patients had myofilament-HCM, including 12 with MYBPC3-HCM and 9 with MYH7-HCM. As compared with healthy heart tissue, levels of myofilament proteins were increased in patients manifesting a mutation in either gene. Patients with a frameshift mutation predicted to truncate MYBPC3 exhibited marked disturbances in protein localization as compared with missense mutations in either MYBPC3 or MYH7 . Conclusions— In this first expression study in human HCM tissue, increased myofilament protein levels in patients with either MYBPC3 - or MYH7- mediated HCM suggest a poison peptide mechanism. Specifically, the mechanism of dysfunction may vary according to the genetic subgroup suggested by a distinctly abnormal distribution of myofilament proteins in patients manifesting a truncation mutation in MYBPC3 .

Objective Delivery of a collapsable aortic valve prosthesis via the left ventricular (LV) apex has proven problematic clinically. We describe our experience with a novel technique for a laparoscopic transdiaphragmatic approach to the LV outflow tract (LVOT). Methods Laparoscopic transabdominal access to the left ventricle was achieved in four live swine and one human cadaver using three abdominal laparoscopic trocars. Pericardioscopy and cardioscopy were performed. A hemostatic purse-string suture was placed laparoscopically at the apex of the left ventricle in one pig, and an instrument passed through the purse-string and into the LVOT. After the procedure, a thoracotomy was performed and the heart explanted for gross examination. Results Transdiaphragmatic exposure of the LV apex was accomplished at a mean of 23 minutes. Hemodynamic stability was maintained in all animals and the pleural cavities were not violated. Pericardioscopy allowed visualization of both right and left pulmonary veins along with the left atrial appendage. In situ cardioscopy confirmed that access to the LVOT and the aortic annulus was possible from the LV apex entry site. Conclusions Laparoscopic transdiaphragmatic approach to the LVOT is a possible route for minimally invasive beating heart aortic valve implantation. This strategy permits a straight transapical line of access to the aortic valve; avoiding the potential for cardiac torsion via a thoracotomy.

Background and Purpose— Embolic events have long been thought to occur in patients with cardiac tumors secondary to embolization of tumor fragments; however, there are no large studies examining the epidemiology and occurrence of embolism in this group of patients. Methods— From 1957 to 2006, 323 consecutive patients with primary cardiac tumors were treated surgically at our institution. Of these, patients who experienced an embolic event included 80 (cerebrovascular accident 31 [9.7%], transient ischemic attack 30 [9.3%], and other 19 [6%]). Those with no history of an embolic event (n=243 [75%]) were defined as control subjects. Results— Age was similar between the case and control groups (mean 54.5 versus 53.9 years, P =0.8). A multivariate logistic regression model including tumor location, tumor burden, tumor histology, and cerebrovascular risk factors, indicated that left atrial tumors (OR, 1.95; P =0.04), aortic valve tumors (OR, 4.17; P =0.002), and smaller tumor burden (OR, 2.20; P =0.01) were the most significant factors in the occurrence of embolism ( P <0.001). The presence of mitral regurgitation (OR, 0.12; P =0.006) and decreased functional status (New York Heart Association III/IV; OR, 0.31; P <0.001) were protective against the occurrence of embolism. Follow-up was obtained in 82% at a mean follow-up time of 6.17±6.9 years. There were no recurrent embolic events at follow-up. A Kaplan-Meier survival curve demonstrated no difference in survival between both groups ( P =0.78). Conclusion— Aortic valve and left atrial tumors have the greatest anatomic risk for embolism. Furthermore, patients with smaller tumors, minimal symptomatology, and no evidence of mitral regurgitation have a high risk of embolism. Cardiac tumors can be resected with low early mortality, and late survival after operation in the context of an embolic event is similar to patients with cardiac tumors who undergo resection for other indications.