Catheter balloon dilatation for discrete subaortic stenosis in the adult

Proceedings of TCT: current status of catheter-based mitral valve repair therapies

A variety of advances have recently facilitated development of methods to treat mitral regurgitation using catheter techniques via the percutaneous route. These include placing devices into the coronary sinus to support the mitral annulus and direct percutaneous leaflet repair. These approaches are already attractive for use in older patients and will hopefully make treatments available to many with no current options.

Percutaneous Treatment of Valvular Heart Disease: Catheter‐Based Aortic Valve Replacement and Mitral Valve Repair Therapies

Until recently, percutaneous catheter therapy for valvular heart disease was limited to catheter balloon valvuloplasty for aortic, mitral, or pulmonic stenosis. A number of new approaches to percutaneous valve therapy are now developing rapidly, including methods for catheter-based valve replacement and repair. Stent-mounted valve prostheses have been successfully implanted in the pulmonic and aortic positions. These devices have been constructed using pericardial valve leaflets mounted inside balloon-expandable or self-expanding stents and have been used in patients who are high risk for valve replacement surgery. Percutaneous valve repair is also being developed for mitral regurgitation. Direct leaflet repair and percutaneous annuloplasty are being employed in clinical trials. All the percutaneous approaches are based on existing surgical techniques and offer less invasive alternatives. The era of percutaneous valve therapy has clearly arrived, and ongoing trials will define the clinical role for these new therapies.

Proceedings of the TCT: Balloon Aortic Valvuloplasty Appropriate for Elderly Valve Patients

Balloon aortic valvuloplasty (BAV) has been a highly successful therapy for children and young adults with aortic valve stenosis, resulting in both symptomatic improvement and durable increases in the aortic valve area. Despite enthusiasm for BAV in older adult patients with aortic valve stenosis in the mid-1980s, the therapy has had disappointing medium- and long-term outcomes. Survival of patients with aortic valve stenosis does not increase with BAV, and restenosis occurs in the vast majority of patients within 6-24 months after therapy. Despite these limitations, most patients are symptomatically improved for a year or more. BAV remains an effective palliative therapy for selected patients.

Interventional cardiac catheterization

Over the past decade, transcatheter interventions have become increasingly important in the treatment of patients with congenital heart lesions. These procedures may be broadly grouped as dilations (e.g., septostomy, valvuloplasty, angioplasty, and endovascular stenting) or as closures (e.g., vascular embolization and device closure of defects). Balloon valvuloplasty has become the treatment of choice for patients in all age groups with simple valvar pulmonic stenosis and, although not curative, seems at least comparable to surgery for congenital aortic stenosis in newborns to young adults. Balloon angioplasty is successfully applied to a wide range of aortic, pulmonary artery, and venous stenoses. Stents are useful in dilating lesions of which the intrinsic elasticity results in vessel recoil after balloon dilation alone. Catheter-delivered coils are used to embolize a wide range of arterial, venous, and prosthetic vascular connections. Although some devices remain investigational, they have been successfully used for closure of many arterial ducts and atrial and ventricular septal defects. In the therapy for patients with complex CHD, best results may be achieved by combining cardiac surgery with interventional catheterization. The cooperation among interventional cardiologists and cardiac surgeons was highlighted in a report of an algorithm to manage patients with tetralogy of Fallot or pulmonary atresia with diminutive pulmonary arteries, involving balloon dilation, coil embolization of collaterals, and intraoperative stent placement. In this setting, well-planned catheterization procedures have an important role in reducing the overall number of procedures that patients may require over a lifetime, with improved outcomes.

The natural clinical history of canine congenital subaortic stenosis

The demographics and natural clinical history of canine congenital subaortic stenosis (SAS) were evaluated by retrospective analysis of 195 confirmed cases (1967 to 1991), 96 of which were untreated and available for follow-up evaluation. Of these, 58 dogs had left ventricular outflow systolic pressure gradients available for assessment of severity. All 195 dogs were used for demographic analysis. Breeds found to be at increased relative risk included the Newfoundland (odds ratio, 88.1; P < .001), Rottweiler (odds ratio, 19.3; P < .001), Boxer (odds ratio, 8.6; P < .001), and Golden Retriever (odds ratio, 5.5; P < .001). Dogs with mild gradients (16 to 35 mm Hg) and those that developed infective endocarditis or left heart failure were diagnosed at older ages than those with moderate (36 to 80 mm Hg) and severe (> 80 mm Hg) gradients. Of 96 untreated dogs, 32 (33.3%) had signs of illness varying from fatigue to syncope; 11 dogs (11.3%) developed infective endocarditis or left heart failure. Exercise intolerance or fatigue was reported in 22 dogs, syncope in 11 dogs, and respiratory signs (cough, dyspnea, tachypnea) in 9 dogs. In addition, 21 dogs (21.9%) died suddenly. Sudden death occurred mainly in the first 3 years of life, primarily but not exclusively, in dogs with severe obstructions (gradient, > 80 mm Hg; odds ratio, 16.0; P < .001). Infective endocarditis (6.3%) and left heart failure (7.3%) tended to occur later in life and in dogs with mild to moderate obstructions.(ABSTRACT TRUNCATED AT 250 WORDS)

Restenosis following successful balloon valvuloplasty: bone formation in aortic valve leaflets

Restenosis after balloon aortic valvuloplasty is common, occurring in as many as half or more of patients in the first year. To gain understanding of the mechanisms of restenosis we examined results of second dilatations and the histology of restenosed valves excised during valve replacement for restenosis. Eleven patients with calcific aortic stenosis underwent second valvuloplasty for restenosis. The mean age was 82 +/- 6 years. The interval between first and second dilatation was 14.7 +/- 8.5 months. First valvuloplasty resulted in an increase in valve area from 0.63 +/- 0.23 to 1.09 +/- 0.32 cm2 (p < 0.01). The valve area found after symptoms recurred was 0.56 +/- 0.18 cm2, not significantly different from the prevalvuloplasty dimensions. Second dilatation resulted in a mean aortic valve area of .76 +/- 0.22 cm2 (p = 0.011 vs results of first valvuloplasty). The change in valve area after first dilatation was 0.45 +/- 0.17 vs 0.20 +/- 0.13 cm2 after second dilatation (p < 0.01). Multiple histologic sections from excised, restenosed valves from five additional patients showed zones of active capillary and cellular proliferation and fibrosis in crevices between calcific nodules in three cases. Associated foci of ossification were seen in two of these. Stenotic nonvalvuloplasty control valves (n = 19) showed no ossifications. In conclusion, histologic changes in restenosed valves differ from those seen initially in calcific aortic stenosis, with granulation tissue, fibrosis, and ossification being present. These findings may help to explain the limited results of second dilatations for restenosis.

Immediate and follow-up results of transluminal balloon dilation for discrete subaortic stenosis

This study presents the findings in 33 patients with discrete subaortic stenosis who were treated by percutaneous balloon dilation and were followed up for 2 months to 6.2 years (mean 34 +/- 21 months). The mean age was 13 +/- 11 years; 10 (30%) were female and 23 (70%) male. Associated malformations were observed in nine patients (27%). All patients underwent noninvasive studies and cardiac catheterization. The mean value to membrane distance was 4.5 +/- 2 mm/m2. After balloon dilation, the pressure gradient from the left ventricle to the aorta decreased from 68 +/- 30 to 20 +/- 13 mm Hg (p less than 0.00001); there were no significant changes in the degree of aortic regurgitation. A fluttering and widely mobile remaining membrane was clearly visualized after dilation. Better immediate results were obtained in patients with a smaller baseline gradient, a larger aortic anulus and a longer valve to membrane distance. Serial follow-up echographic studies were available in 30 patients, and 18 hemodynamic reevaluations were performed in 13 patients. However, seven patients who demonstrated restenosis underwent redilation at a mean of 29 +/- 17 months after the first dilation. Redilation in six of the seven patients obtained benefits similar to those observed at the first dilation. Only one patient with unsuccessful redilation required surgery. The mean value of the last explored residual gradient (on hemodynamic or Doppler study) in the remaining 32 patients was 21 +/- 10 mm Hg. No significant changes were observed in the angiographic evolution of aortic regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Transluminal balloon dilatation for discrete subaortic stenosis in adults and children: early and intermediate results

Seven patients (four adults, three children) with discrete subaortic membranous stenosis underwent balloon dilatation using a single or double balloon technique with reduction in systolic gradient across the membrane from 100.42 +/- 19.23 to 29.14 +/- 12.54 mmHg (P less than 0.001). Echocardiography demonstrated thin membranes in all the patients and postprocedure torn fragments could be visualized. The excellent hemodynamic benefits are sustained during 4-24 months follow-up. The results indicate that transluminal balloon dilatation can be a safe and effective treatment for thin subaortic membrane.

Subaortic obstruction: intraoperative echocardiography as an adjunct to operation

Fourteen patients undergoing operation for subaortic obstruction (membranous obstruction in 11 patients, tunnel obstruction in 2 patients, obstruction due to reduplicated mitral valve tissue in 1 patient) were evaluated by intraoperative epicardial echocardiography. In all 9 patients with "discrete" obstruction who underwent prebypass epicardial echocardiography, the septal and lateral attachments of the lesion were correctly demonstrated. The precise extent of tunnel stenosis was seen in both patients. The lateral attachment of the membrane in 4 patients and multiple extensions in another 2 were identified by the epicardial study (having been missed on precordial echocardiography). The discrete membrane was enucleated in 10 of the 11 patients and was partially resected in 1. One tunnel obstruction was completely relieved; the other was partially relieved. Reduplicated mitral valve tissue in the remaining patient was completely resected. Epicardial imaging after bypass showed remnants of the membrane in 2 patients. Intraoperative Doppler echocardiography and color flow imaging confirmed the absence of clinically significant residual gradients (less than 20 mm Hg) in all but 1 patient with tunnel obstruction. Epicardial imaging provided excellent morphological information about obstructive lesions of the left ventricular outflow tract and enabled immediate assessment of surgical repair.