Burkhart, Harold M.

Congenital heart diseases, including single ventricle circulations, are clinically challenging due to chronic pressure overload and the inability of the myocardium to compensate for lifelong physiological demands. To determine the clinical relevance of autologous umbilical cord blood–derived mononuclear cells (UCB-MNCs) as a therapy to augment cardiac adaptation following surgical management of congenital heart disease, a validated model system of right ventricular pressure overload due to pulmonary artery banding (PAB) in juvenile pigs has been employed. PAB in a juvenile porcine model and intramyocardial delivery of UCB-MNCs was evaluated in three distinct 12-week studies utilizing serial cardiac imaging and end-of-study pathology evaluations. PAB reproducibly induced pressure overload leading to chronic right ventricular remodeling including significant myocardial fibrosis and elevation of heart failure biomarkers. High-dose UCB-MNCs (3 million/kg) delivered into the right ventricular myocardium did not cause any detectable safety issues in the context of arrhythmias or abnormal cardiac physiology. In addition, this high-dose treatment compared with placebo controls demonstrated that UCB-MNCs promoted a significant increase in Ki-67-positive cardiomyocytes coupled with an increase in the number of CD31+ endothelium. Furthermore, the incorporation of BrdU-labeled cells within the myocardium confirmed the biological potency of the high-dose UCB-MNC treatment. Finally, the cell-based treatment augmented the physiological adaptation compared with controls with a trend toward increased right ventricular mass within the 12 weeks of the follow-up period. Despite these adaptations, functional changes as measured by echocardiography and magnetic resonance imaging did not demonstrate differences between cohorts in this surgical model system. Therefore, this randomized, double-blinded, placebo-controlled pre-clinical trial establishes the safety of UCB-MNCs delivered via intramyocardial injections in a dysfunctional right ventricle and validates the induction of cardiac proliferation and angiogenesis as transient paracrine mechanisms that may be important to optimize long-term outcomes for surgically repaired congenital heart diseases.

The modified Fontan procedure may be complicated by prolonged pleural drainage. Predisposing factors are not fully understood. This study examines perioperative variables associated with prolonged effusions. We examined the Fontan procedure in 41 patients. Mean age was 45 months (range, 9 to 113 months). Mean weight was 14.7 kg (range, 6.9 to 30.4 kg). Diagnoses included tricuspid atresia in 29 per cent, pulmonary atresia in 12 per cent, and double-outlet right ventricle in 12 per cent. Fontan revisions were excluded. The extracardiac Fontan was performed in 22 patients (54%) and the lateral tunnel (LT) in 18 (44%). Fenestration was performed in 56 per cent. Ten patients (24%) had prolonged pleural effusions. Mean chest tube output (24.2 vs 14.1 mL/kg/d, P < 0.01), days with chest tubes (10.2 vs 5.8 days, P < 0.01), and length of stay (20.8 vs 8.13 days, P < 0.01) were significantly greater in those with effusions. Preoperative mean pulmonary artery pressure was higher in patients with prolonged effusions (12.7 vs 9.90 mmHg, P = 0.001). No other factors were identified as risk factors. Prolonged pleural effusions (greater than 14 days) are common after the modified Fontan procedure. A higher preoperative mean pulmonary artery pressure may be predictive of these effusions. Fenestration, type of Fontan reconstruction, and size of extracardiac conduit did not predispose to postoperative effusions.

Objective Percutaneous aortic valve implantation within native valve calcium has progressed to clinical use despite the absence of data proving equivalence to complete surgical excision and prosthetic valve replacement. A novel self-expanding sutureless bovine pericardial prosthesis (Sorin Perceval) derived from a proven stented valve has been successfully used in humans recently through an open transaortic approach. We sought to develop a minimally invasive technique for native aortic valve excision and sutureless prosthetic aortic valve replacement using robot assistance. Methods The da Vinci S-HD system was used to open and suspend the pericardium anterior to the phrenic nerve in cadavers. A transthoracic cross-clamp was placed across the midascending aorta, following which a transverse aortotomy was made. The native aortic valve cusps were excised, and annular calcium was removed with robotic instruments. After placement of three guide sutures, the Perceval self-expanding pericardial prosthesis mounted on a flexible delivery system was inserted through a working port and lowered into the aortic annulus. Results Successful implantation of all valves was possible using a 3-cm right second intercostal space working port, along with two additional 1-cm instrument ports. A standard transverse aortotomy was sufficient for examination/debridement of the native aortic valve cusps, sizing of the annulus, and deployment of the nitinol-stented, bovine pericardial prosthesis. Delivery, seating, and stability of the device were easily confirmed above and below the aortic valve annulus using the robotic camera. Conclusions Complete excision of diseased native aortic valve cusps with robot assistance facilitates accurate and reproducible aortic valve replacement using a novel self-expanding sutureless version of a proven bovine pericardial prosthesis. This approach is comparable to the current surgical gold standard and is ready for clinical use as an alternative to percutaneous aortic valve implantation.

Background— Severe primary (degenerative) mitral regurgitation (MR) is repaired with durable results when simple single-scallop disease is addressed. The midterm quality outcomes of minimally invasive repair for complex disease are unknown, however. Methods and Results— From January 2008 to January 2015, 487 patients (56±11 years, 360 men, ejection fraction 65±6%, 98.8% complete follow-up) underwent robotic mitral valve repair for severe nonischemic degenerative MR. Simple pathology was addressed in 289 of 487 (59%) patients, and complex repair (all others) was performed in 198 of 487 (41%). Four patients died during follow-up with a 5-year survival rate 99.5% (99.4% simple; 99.5% complex; hazard ratio, 0.48; 95% confidence interval, 0.05–4.59); and New York Heart Association functional class I/II was documented in 97.9% (477/487). Eight patients had recurrence of moderate-to-severe MR (4 simple, 4 complex), with a 5-year freedom from MR of 94.6% (96.2% simple; 92.7%, complex; P =0.67; hazard ratio, 1.36; 95% confidence interval, 0.34–5.43). Seven patients (2 simple, 5 complex), underwent mitral reoperation, with a 5-year freedom from reoperation of 97.7% (99.1% simple; 95.7% complex; P =0.13; hazard ratio, 3.35; 95% confidence interval, 0.65–17.32). Conclusions— At a large tertiary care referral center, midterm quality outcomes after robotic correction of degenerative MR are excellent, with very high survival, infrequent complications, and a low likelihood of MR recurrence, regardless of mitral valve repair complexity. Awareness of these improvements in outcome is important to inform contemporary decisions regarding high-quality alternatives to conventional and percutaneous mitral repair.

Abstract Congenital heart diseases (CHDs) requiring surgical palliation mandate new treatment strategies to optimize long-term outcomes. Despite the mounting evidence of cardiac regeneration, there are no long-term safety studies of autologous cell-based transplantation in the pediatric setting. We aimed to establish a porcine pipeline to evaluate the feasibility and long-term safety of autologous umbilical cord blood mononuclear cells (UCB-MNCs) transplanted into the right ventricle (RV) of juvenile porcine hearts. Piglets were born by caesarean section to enable UCB collection. Upon meeting release criteria, 12 animals were randomized in a double-blinded fashion prior to surgical delivery of test article (n = 6) or placebo (n = 6). The UCB-MNC (3 × 106 cells per kilogram) or control (dimethyl sulfoxide, 10%) products were injected intramyocardially into the RV under direct visualization. The cohorts were monitored for 3 months after product delivery with assessments of cardiac performance, rhythm, and serial cardiac biochemical markers, followed by terminal necropsy. No mortalities were associated with intramyocardial delivery of UCB-MNCs or placebo. Two animals from the placebo group developed local skin infection after surgery that responded to antibiotic treatment. Electrophysiological assessments revealed no arrhythmias in either group throughout the 3-month study. Two animals in the cell-therapy group had transient, subclinical dysrhythmia in the perioperative period, likely because of an exaggerated response to anesthesia. Overall, this study demonstrated that autologous UCB-MNCs can be safely collected and surgically delivered in a pediatric setting. The safety profile establishes the foundation for cell-based therapy directed at the RV of juvenile hearts and aims to accelerate cell-based therapies toward clinical trials for CHD.

Background— Most patients with repaired tetralogy of Fallot require pulmonary valve replacement (PVR), but the evaluation for and management of ventricular arrhythmia remain unclear. This study is aimed at clarifying the optimal approach to this potentially life-threatening issue at the time of PVR. Methods and Results— A retrospective analysis was performed on 205 patients with repaired tetralogy of Fallot undergoing PVR at our institution between 1988 and 2010. Median age was 32.9 (range, 25.6) years. Previous ventricular tachycardia occurred in 16 patients (8%) and 37 (16%) had left ventricular dysfunction, defined as left ventricular ejection fraction <50%. Surgical right ventricular outflow tract cryoablation was performed in 22 patients (10.7%). The primary outcome was a combined event including ventricular tachycardia, out-of-hospital cardiac arrest, appropriate implantable cardioverter defibrillator therapy, and sudden cardiac death. Freedom from the combined event at 5, 10, and 15 years was 95%, 90%, and 79%, respectively. In the first year after PVR, 2 events occurred. Conversely, in the 22 patients who underwent surgical cryoablation, a single event occurred 7 years after PVR. A history of ventricular tachycardia and left ventricular dysfunction was associated with higher risk for the combined event (hazard ratio, 4.7; P =0.004 and hazard ratio, 0.8; P =0.02, respectively). Conclusions— Patients with repaired tetralogy of Fallot undergoing PVR with history of ventricular tachycardia or left ventricular dysfunction appear to be associated with a higher risk of arrhythmic events after operation. Events in the first year after PVR are rare, and in select high-risk patients, surgical cryoablation does not seem to increase arrhythmic events and may be protective.

Objective: To compare the safety and effectiveness of video-assisted thoracic surgery (VATS) versus conventional median sternotomy (open) in the repair of secundum atrial septal defect (ASD) or patent foramen ovale (PFO). Design: Among 415 consecutive patients undergoing open or VATS ASD/PFO closure between 1993 and October 2012, 153 patients were compared using 2:1 frequency matching (n = 102 open vs 51 VATS). Matching variables include age, gender, body surface area, past medical history of neurologic events, and need of patch closure. Median age was 43 years (3-71 years), and 67% were female. Results: There were no early deaths in either group. There were no conversions to open sternotomy. Although mean cross-clamp time (14.5 ± 7.6 vs 26.3 ± 13.2 minutes, P < .001) and bypass time (31.7 ± 13.8 vs 60.9 ± 20.9 minutes, P < .001) were longer in the VATS group, patients who underwent VATS had shorter postoperative ventilation time (7.5 ± 6.4 vs 4.4 ± 2.8 hours, P = .03) with 62.7% extubated in the operating room, along with shorter intensive care unit stay (26.7 ± 10.8 vs 19.1 ± 9.9 hours, P < .001) and hospital stay (5.2 ± 1.9 vs 3.5 ± 0.9 days, P < .001). At early follow-up (mean 1.5 years, maximum 4.2 years), there was no difference in need for reintervention. Of the 27 patients who underwent VATS ASD/PFO closure for a neurologic event, none had a recurrence. Conclusion: The use of VATS provides a safe, equally effective alternative to conventional sternotomy for ASD/PFO closure, using a less invasive approach.