W. Robert Morrow

Acute results of balloon angioplasty of native coarctation versus recurrent aortic obstruction are equivalent

OBJECTIVES This study sought to compare the immediate results and risk factors for suboptimal outcomes of percutaneous balloon angioplasty for native versus recurrent aortic obstruction. BACKGROUND Some cardiology centers have been reluctant to adopt balloon angioplasty for treatment of native aortic coarctation, while advocating balloon angioplasty over an operation for treatment of postsurgical or recurrent aortic obstruction. METHODS Acute results were analyzed from 970 procedures (422 native and 548 recurrent lesions) performed between 1982 and 1995 in 907 patients from 25 centers. An acute suboptimal outcome was defined as one or more of the following: residual systolic pressure gradient > or = 20 mm Hg, residual proximal to distal systolic pressure ration > or = 1.33 or a major complication (death, aortic transmural tear, stroke). RESULTS Bal loon angioplasty significantly (p = 0.0001) increased lesion diameter fo r both native (mean [+/= SD] 128 +/= 94%) and recurrent aortic obstruction (97 +/= 87%), with a significantly greater increase in the native group (p = 0.0001). A reduction in systolic pressure gradients was significant in both groups (p = 0.0001), but slightly higher (p = 0.01) for native (-74 +/- 24%) versus recurrent obstruction (-70 +/- 31%). Death associated with angioplasty was reported in 0.7% of patients with native and in 0.7% of patients with recurrent lesions (p = 1.00). An acute suboptimal outcome was noted with angioplasty in 19% of native and in 25% of recurrent lesions (p = 0.04). Significant independent risk factors included higher preangioplasty systolic gradient (odds ratio [OR] 1.39/10-mm Hg increment; 95% confidence interval [CI] 1.28 to 1.50, p = 0.0001), earlier study date (OR 0.92/1-year increment, 95% CI 1.02 to 1.26, p = 0.02) and recurrent obstruction (OR 1.39 vs. native lesions, 95% CI 1.00 to 1.94, p = 0.05). CONCLUSIONS Acute results and complications of balloon angioplasty of native coarctation appear to be equivalent or slightly superior to those of recurrent aortic obstructions.

Blade and balloon atrial septostomy for left heart decompression in patients with severe ventricular dysfunction on extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is used as circulatory support or bridge to transplantation in patients with severe left ventricular (LV) dysfunction. Left heart decompression is needed to reduce pulmonary edema, prevent pulmonary hemorrhage, and reduce ventricular distention that may aid in recovery of function. We reviewed our experience from November 1993 to December 1997 with 10 patients having severe LV dysfunction (7 myocarditis, 3 dilated cardiomyopathy) who required circulatory support with ECMO and who underwent left heart decompression with blade and balloon atrial septostomy (BBAS). Patients ranged in age from 1 to 24 years (median, 3 years). Indications for BBAS included left atrial/left ventricular distension (10), pulmonary edema/hemorrhage (9), or severe mitral regurgitation (2). BBAS was performed electively in eight patients and urgently in two patients. BBAS was performed while on ECMO in seven patients and pre‐ECMO in three. A femoral venous approach was used in all patients. ECMO patients were fully heparinized. Transseptal puncture was required in nine patients while one patient had a patent foramen ovale. Blade septostomy was performed in all patients. Enlargement of the defect was then performed by stationary balloon dilation in nine and Rashkind balloon atrial septostomy in one. Balloon diameters ranged from 10 to 20 mm. Sequential balloon inflations were performed in some patients. Adequacy of the atrial septal defect (ASD) was confirmed by pressure measurement and echocardiography. Adequate left heart decompression was achieved in all patients. Pulmonary edema improved in nine of nine patients. Left atrial mean pressure fell from a mean of 30.5 mm Hg, (range, 12–50 mm Hg) to 16 mm Hg (range, 9–24 mm Hg). Left atrial to right atrial pressure gradient fell from a mean of 20 mm Hg pre‐BBAS to 3 mm Hg post‐BBAS. ASDs ranged in size from 2.5 to 8 mm (mean, 5.9 mm). Complications included needle perforation of the left atrium without hemodynamic compromise (one), ventricular fibrillation requiring defibrillation (one), and hypotension following BBAS which responded to volume infusion (two). Duration of ECMO ranged from 41 hr to 704 hr (mean, 294 hr). Seven patients survived and four patients had recovery of normal LV function. Of those who recovered, two had no ASD at follow‐up while two ASDs are patent 14 days and 3 months post‐BBAS. Three patients underwent successful cardiac transplantation. Three patients died, all of whom had multisystem organ failure with or without sepsis. A patent ASD was noted at transplant (three) or autopsy (two). No patient required a second BBAS. BBAS alleviates severe left atrial hypertension and pulmonary edema. In addition, BBAS avoids the potential bleeding complications of surgical left heart decompression. Stationary balloon dilation of the atrial septum is an effective alternative to Rashkind balloon septostomy in older patients. BBAS achieves left heart decompression that may permit recovery of LV function or allow extended ECMO support as a bridge to transplant. Cathet. Cardiovasc. Intervent. 46:179–186, 1999.

Risk factors for recurrent rejection in pediatric heart transplantation: a multicenter experience.

BACKGROUND Cardiac allograft rejection remains as a primary cause of death in the first 3 years after pediatric heart transplantation. Multiple episode of acute rejection in adult heart transplant recipients may accelerate the development of graft vasculopathy. We sought to quantify the time-related probability of recurrent rejection and identify risk factors for the development of recurrent rejection. METHODS We analyzed data from 847 pediatric recipients who underwent transplantation between January 1, 1993 and December 31, 1998 at 22 centers in the Pediatric Heart Transplant Study (PHTS). Recurrent rejection and risk factors were evaluated using univariate and multivariate analyses. RESULTS Five hundred fifty two patients had 1,072 rejection events and were the subject of the analyses. The highest risk of recurrent rejection occurs within 1 month after resolution of a previous rejection episode. Risk factors for recurrent rejection include the number of previous rejection events, the elapsed time since a previous rejection episode, and subjects of either Hispanic or African-American descent. Rejection associated with hemodynamic compromise and late rejection is associated with higher mortality. CONCLUSIONS Recurrent rejection is a risk factor for mortality, especially in the presence of hemodynamic compromise. This association appears independent of the time post-transplantation. Use of surveillance biopsies appears warranted throughout the life of the transplant individual. Retransplantation should be considered among these subjects with recurrent rejection.

Quantification of myocardial blood flow and flow reserve in children with a history of kawasaki disease and normal coronary arteries using positron emission tomography

OBJECTIVES The purpose of this investigation was to determine whether myocardial blood flow and flow reserve, based on quantitative measurements derived from positron emission tomographic (PET) imaging, would be globally impaired in children with a previous history of Kawasaki disease and normal epicardial coronary arteries. BACKGROUND Kawasaki disease is an acute inflammatory process of the arterial walls that results in panvasculitis in early childhood. Children with a history of Kawasaki disease and normal epicardial coronary arteries were previously considered to have normal coronary flow reserve. However, recent studies have reported exercise-induced regional perfusion abnormalities on single-photon positron emission tomographic (SPECT) imaging. METHODS We assessed myocardial blood flow and flow reserve at rest and during adenosine stress with nitrogen-13 ammonia and PET in 10 children with a history of Kawasaki disease and in 10 healthy young adult volunteers. All children had acute Kawasaki disease 4 to 15 years before the PET study. None of the children had epicardial coronary artery abnormalities at the acute stage of the disease or during follow-up, as assessed by echocardiography. RESULTS Rest blood flows normalized to the rate-pressure product, an index of cardiac work, were similar in both the patients with Kawasaki disease and healthy adult volunteers (82 +/- 14 vs. 77 +/- 16 ml/100 g per min [mean +/- SD], p = NS). However, hyperemic blood flows were significantly lower in the patients with Kawasaki disease than in the control subjects (263 +/- 64 vs. 340 +/- 57 ml/100 g per min, p = 0.01). As a result, estimates of myocardial flow reserve were lower in the patients with Kawasaki disease than in the healthy young adult volunteers (3.2 +/- 0.7 vs. 4.6 +/- 0.9, p = 0.003). In addition, total coronary resistance was higher in the patients with Kawasaki disease than in the healthy adult volunteers (33 +/- 11 vs. 24 +/- 5 mm Hg/ml per g per min, p = 0.04). Quantitative analysis of perfusion images demonstrated no evidence of regional perfusion abnormalities. CONCLUSIONS Children with a previous history of Kawasaki disease and normal epicardial coronary arteries exhibit normal rest myocardial blood flows but reduced hyperemic flows and flow reserve. The abnormal hyperemic blood flows and flow reserve suggest an impaired vasodilatory capacity, possibly due to residual damage of the coronary microcirculation.

Death after rejection with severe hemodynamic compromise in pediatric heart transplant recipients : A multi-institutional study

BACKGROUND Rejection with severe hemodynamic compromise results in high mortality in adult transplant patients. This study determines the incidence, outcome and risk factors for rejection with severe hemodynamic compromise in a multi-institutional study of pediatric heart transplant recipients. METHODS Data from 847 patients transplanted between 1/1/93 and 12/31/98 at 18 centers in the Pediatric Heart Transplant Study were analyzed. Rejection with severe hemodynamic compromise was defined as a clinical event occurring beyond 1 week postoperatively, which led to augmentation of immunosuppression and use of inotropic therapy. Actuarial freedom from such rejection and death after rejection were determined and risk factors sought. RESULTS Among 1,033 rejection episodes in 532 patients, 113 (11%) episodes were associated with severe hemodynamic compromise in 95 patients. The highest risk for severe rejection was in the first year. Risk factors were older recipient age (p >.05) and non-white race (p >.001). Survival after an episode was poor (60%), and biopsy score did not affect outcome. Deaths were due to rejection (n = 14), other cardiac causes (n = 17), infection (n = 5), lymphoma (n = 2), pulmonary causes (n = 2), and thrombosis (n = 1). CONCLUSIONS Rejection with severe hemodynamic compromise occurs in 11% of pediatric patients, irrespective of age, sex or biopsy score, and mortality is high. Non-white race and older recipient age are independent risk factors for rejection with severe hemodynamic compromise. Aggressive treatment and close surveillance should be crucial components of protocols aimed at reducing the high mortality.

Bridge to Cardiac Transplant in Children: Berlin Heart versus Extracorporeal Membrane Oxygenation

BACKGROUND For small children requiring mechanical circulatory support as a bridge to transplantation (BTT), extracorporeal membrane oxygenation (ECMO) has been the only option until the recent introduction of the Berlin Heart EXCOR ventricular assist device (Berlin Heart AG, Berlin, Germany). We reviewed our recent experience with these two technologies with particular focus on early outcomes. METHODS Data for 55 consecutive children undergoing BTT between 2001 and 2008 were abstracted from an institutional database. The analysis excluded 13 patients because EXCOR was not used for acute postcardiotomy BTT. Patients were divided into ECMO (n = 21) and EXCOR groups (n = 21). Specific end points included survival to transplant, overall survival, and bridge to recovery. Incidences of adverse events and the duration of support were determined. RESULTS Groups were similar in weight, age, and etiologies of heart failure. Likewise, the incidences of stroke and multisystem organ failure were similar. Survival to transplant, recovery, or continued support was 57% in ECMO and 86% in EXCOR (p = 0.040). EXCOR patients had overall significantly better survival (p = 0.049). Two ECMO patients and 1 EXOR patient were bridged to recovery. The mean duration of support was 15 +/- 12 days in the ECMO group and 42 +/- 43 days in the EXCOR group (p < 0.001). CONCLUSIONS In children requiring BTT, EXCOR provided substantially longer support times than ECMO, without significant increase in the rates of stroke or multisystem organ failure. Survival to transplant and long-term survival was higher with EXCOR.

Preliminary single center North American experience with the Berlin Heart pediatric EXCOR device.

For children requiring mechanical circulatory support as a bridge to cardiac transplantation in North America, options previously were limited to extracorporeal membrane oxygenation (ECMO) or centrifugal pump ventricular assist, both of which were suitable for only very short term application and were associated with significant complications and limitations. The Berlin Heart EXCOR ventricular assist device (VAD) was recently introduced into practice in North America to address this deficiency. We report a preliminary single center experience with the EXCOR in 17 children, 13 who received only a left-sided pump and four who required biventricular support. Before EXCOR placement, six patients were on ECMO, and one was on a centrifugal VAD. Eleven children were bridged to transplantation, one was bridged to recovery, and one remains on support. Three children died during support and one died after explantation. There was one late death nearly 2 years after transplant. Complications included stroke in seven patients, two of which were ultimately fatal. Five patients required re-operations for bleeding or evacuation of hematoma. Despite a disappointing rate of neurologic morbidity, our preliminary experience with the EXCOR has been very encouraging.

Standardized Management Improves Outcomes after the Norwood Procedure

BACKGROUND In the past decade, many advances in the care of patients undergoing the Norwood procedure (NP) have been reported, but management remains nonstandardized at many institutions. We studied the impact of a standardized management protocol for neonates undergoing NP. METHODS Care of NP patients has been protocol-driven at our institution since 2005, with routine use of regional low flow perfusion; near infrared spectroscopy; phenoxybenzamine with cardiopulmonary bypass; delayed sternal closure; peritoneal drainage; gastrostomy tubes; postoperative vocal cord assessment; and a home surveillance program of daily weight and oxygen saturation measurement. Patients undergoing NP from 2001 to 2004 (n = 40, group 1), in whom these interventions were only selectively employed, were retrospectively compared with those receiving standardized management from 2005 to 2007 (n = 40, group 2), with endpoints of survival in-hospital and to stage 2 palliation (S2P). Effect of protocol elements on outcome was evaluated by univariate and multivariate analyses. RESULTS Hospital survival (95% vs. 70%, P= .003) and survival to S2P (85% vs. 58%, P= .006) was better in group 2. By univariate analysis, regional low flow perfusion, gastrostomy usage, and near infrared spectroscopy were associated with improved hospital and survival to S2P. In multivariable analysis, gastrostomy usage was associated with improved hospital survival (P= .027) and survival to S2P (P= .049), while our home surveillance program was a predictor of survival to S2P (P= .016). CONCLUSION Protocol-driven management of NP patients was associated with better hospital survival and survival to S2P. Among protocol elements, gastrostomy usage was linked to both improved hospital survival and survival to S2P. Home surveillance was associated with increased survival to S2P.

Risk Factors for Prosthesis Failure in Pulmonary Valve Replacement

BACKGROUND After initial right ventricular outflow tract reconstruction, replacement of the pulmonary valve (PVR) with a bioprosthetic valve may be performed. Bioprosthetic valves fail (PVF) and require repeat replacement. Identification of risk factors for PVF would be useful for clinicians choosing among various options for the initial PVR. METHODS We retrospectively analyzed outcomes of 169 consecutive patients (55% male) with repaired tetralogy of Fallot or pulmonary stenosis undergoing a first PVR. Data were abstracted from the medical records, including gender, diagnosis, indication for PVR, age at PVR (< 10 years or ≥ 10 years), type of valve, and time of PVF. Actuarial freedom from PVF was compared by log rank and parametric survival analysis. Risk factors for PVF were analyzed by univariate and multivariate methods. Prosthesis types for PVR were pulmonary homograft in 56, stented porcine valve in 16, stented porcine valve in Dacron (DuPont, Wilmington, DE) conduit in 26, and bovine pericardial valve in 71. RESULTS Indication for PVR was pulmonary stenosis in 21% and insufficiency in 79%. Median follow-up for the entire cohort was 8 years. PVF occurred in 24 patients at a median time of 5.7 years. Actuarial freedom from PVF at 10 years was 72% for all valve types, 55% for porcine valve in Dacron conduit, 60% for homograft, 75% for porcine valve, and 78% for bovine pericardial valve (p = 0.36). By univariate analysis, young age (p < 0.0001), male gender (p = 0.0017), and indication of pulmonary stenosis (p = 0.015) were risk factors for PVF. In multivariate analysis, tetralogy of Fallot anatomy (p < 0.06), younger age (p < 0.02), and use of a homograft valve (p < 0.02) were risk factors for early PVF (<3 years). Young age (p < 0.0001) at time of PVR was associated with late PVF. CONCLUSIONS Freedom from reoperation for PVR during 10 years of follow-up is excellent. Younger age, tetralogy of Fallot, and use of a homograft valve were risk factors for early PVF. Only younger age at PVR was a significant risk factor for late PVF.

Survival after listing for cardiac transplantation in children

Despite improvement in surgical and medical management of children with congenital and acquired heart disease, cardiac transplantation remains an important therapeutic option for infants and children with end-stage heart disease. Ultimate survival in patients who are listed for transplantation is a function of both mortality while awaiting transplantation and survival after transplantation. Survival of heart transplantation is affected by the severity of illness before transplantation, the unique pathophysiology of certain defects, and the availability of donor hearts. Outcome following listing for transplantation is best studied with the use of recent modifications in statistical methods of competing outcomes analysis. By this analysis a predicted mortality while waiting among all pediatric patients is 20% at 1 year, with 67% undergoing transplantation, 10% still on the list awaiting transplant, and 3% removed from the list. Among infants, most of them with hypoplastic left heart syndrome, 60% will have transplantation by 6 months after listing, with 27% of patients dying while waiting. In infants the major risk factors for death while waiting are the need for inotropic support at listing, smaller size, and recipient blood type. In older children risk factors for death while waiting are Status 1 at listing and a need for mechanical ventilation. Intermediate-term survival after transplant is excellent in all age groups with 86% alive at 6 months, 84% at 1 year, and 73% at 5 years. Survival after transplant in infants is comparable to survival in older children, although the early mortality after transplantation is greater. Infants who have recently undergone sternotomy or received organs from donors who did not die of closed head trauma are more likely to die early after transplant. Among older children risk factors for death after transplantation include the need for a mechanical support device or a younger age in patients greater than 1 year of age. Death following transplantation is primarily related to early graft failure in infants, whereas rejection, infection, and sudden death account for the majority of deaths in older children. Although improved immunosuppressive agents promise to lead to even better survival rates after transplantation, greater access to donors is essential if overall survival is to be improved.