After years of development and preclinical testing, clinical trials of the MicroMed DeBakey VAD began in November 1998 in Europe and in June 2000 in the United States. As of August 2000, 44 patients in Europe and 3 patients in the United States have undergone implantation with the MicroMed DeBakey VAD. In conclusion, data from the European clinical trial of the MicroMed DeBakey VAD support the safety and performance of the device. Results show that the device provides adequate left ventricular and circulatory support in patients with end-stage heart failure without unduly jeopardizing patient safety. Moreover, the device provides advantages not inherent to commercially available pulsatile devices: (1) miniature size, enabling implantation in smaller patients; (2) ease of implantation; (3) reduced surgical bleeding; and (4) a low incidence of postoperative infections, often a limiting factor with other devices. The MicroMed DeBakey VAD European clinical trial is the first demonstration of the compatibility of continuous blood flow with adequate tissue perfusion and overall maintenance of life for up to 4.5 months. This initial experience with the MicroMed DeBakey VAD suggests that the pump can provide circulatory support to bridge patients to cardiac transplantation and may provide an improved quality of life for the patient with end-stage heart failure.
The advances in pediatric interventional cardiac catheterization have changed the therapeutic strategy for many patients with CHD. The procedure of choice for valvar stenosis, recoarctation, collateral vessel occlusion, and branch PA stenosis has moved from the operating room to the catheterization laboratory. Effective and safe transcatheter interventions now exist for closure of ASDs, VSDs, and PDAs and are considered viable alternatives to surgical closure. Other interventional catheterization procedures are currently being investigated to complement the surgical management of patients with complex anatomy, including covered stents for repair of aortic aneurysms, covered stents to complete the Fontan circulation in patients after a modified Glenn shunt, multiple stent designs for all vascular stenoses, percutaneous PA band, and transcatheter resurrection of the pulmonary valve in patients with severe pulmonary regurgitation. The rapid advances in the technology used in the catheterization laboratory will serve to improve the care we provide for our patients and extend the range of interventions performed outside of the operating room. Pediatric cardiologists and congenital heart surgeons must understand each other's interventional techniques and how they can be used in a coordinated fashion. This may involve staged therapy with transcatheter intervention before surgery, transcatheter interventions in the operating room, or modifications of surgical techniques to facilitate future interventional catheterization completion of a staged repair of complex disease. This interaction is essential for the optimal management of our patients with both straightforward lesions and complex anatomy.
Refinements in surgical technique, donor and recipient myocardial preservation, and immunosuppression have brought pediatric heart transplantation for end-stage heart failure (whatever the cause) from the heyday of clinical experimentation to the realm of a viable therapeutic. Heart transplantation in this subpopulation yields excellent early and midterm survival. Acute rejection remains an important cause of morbidity and mortality after heart transplantation in children. Future improvement in quality of life for these patients calls for newer immunosuppressive strategies to reduce acute rejection episodes and ultimately improve long-term graft survival.
The ECF operation is designed to improve postoperative outcome by enhancing factors that are critical in optimal functioning of the Fontan circulation, including preservation of ventricular and pulmonary vascular function, avoidance of dysrhythmias, and prevention of stasis and flow turbulence in the Fontan circuit. Preoperative strategies include an early bidirectional Glenn procedure, and avoiding ancillary intracardiac procedures at the time of the Fontan by performing them at the time of the Glenn operation. Operative strategies include minimizing the duration of CPB by performing the conduit to pulmonary artery anastomosis off bypass, using partial instead of full CPB by cannulating the IVC alone, avoiding hypothermia, avoiding cross-clamping of the aorta, avoiding atrial incisions and suture lines, using a tubular conduit to construct the Fontan pathway, making a large conduit to pulmonary artery anastomosis, incorporating the conduit into aggressive pulmonary arterioplasties, and offsetting of the superior and inferior cavopulmonary anastomoses.
Construction of a monocusp is an easy procedure that adds little, if any time to routine transannular patching of the right ventricular outflow tract. It also adds little cost to the operation when constructed from autologous pericardium. The monocusp's utility in preventing or lessening the impact of pulmonary regurgitation in the early postoperative period has been demonstrated. Its utility as a long-term pulmonary valve substitute will need to await longer-term clinical follow-up currently underway at our institution and others.
TMLR is effective as an isolated procedure in patients with ungraftable vessels and is a useful adjunct to CABG in patients with diffuse and small-vessel disease requiring endarterectomies. The optimal subset of patients who will benefit from isolated TMLR are those primarily with angina rather than congestive failure, who have protected myocardium and uncompromised left ventricular function.
