Discrete Membranous Subaortic Stenosis Research Articles

Successful Percutaneous Balloon Dilatation of Membranous Sub-aortic Stenosis in a 22 Year Old Pregnant Patient

Congenital obstruction of the left ventricular outflow tract comprises a heterogeneous group of disorders, with obstruction potentially occurring below, above, or at the level of the aortic valve. Subvalvular stenosis is the second most common type of left ventricular outflow tract obstruction, of which discrete membranous type is the most common. Although surgical resection of the subaortic membrane is the treatment of choice in discrete membranous subaortic stenosis, in selected patients with isolated membranous subaortic stenosis, without significant aortic insufficiency, percutaneous balloon tearing of the membrane results in reduction in the degree of left ventricular outflow tract obstruction and symptomatic relief. We report a case of 22 year old pregnant patient admitted with NYHA class III breathlessness, found to have discrete membranous subaortic stenosis. Balloon aortic valvuloplasty was performed in the patient with good result. Patient underwent normal vaginal delivery at 38 weeks. Both mother and newborn were asymptomatic. Patient is asymptomatic on subsequent follow-ups.

Medical Management of Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common genetically transmitted cardiomyopathy. The underlying cause of HCM has been attributed to a number of mutations within genes encoding primarily for sarcomeric proteins, which lead to a heterogeneous phenotype of left ventricular hypertrophy in the absence of other causes (eg, hypertension, aortic stenosis, or a discrete membranous subaortic stenosis). Symptoms may range from mild to severely limiting and consist of dyspnea and chest pain with exertion or at rest, syncope, or even sudden cardiac death (SCD). The majority of patients with HCM are treated medically. The primary aim of therapy is to reduce symptoms, but it should also address the risk of SCD. Throughout the years, numerous medical treatments have been used to achieve symptom control in these patients, and include medications such as β-blockers, calcium channel blockers, amiodarone, disopyramide, and angiotensin receptor blockers. This review provides an overview of the current medical treatment of HCM.

Discrete Membranous Subaortic Stenosis Complicated by Infective Endocarditis: A Case Report

Discrete membraneous subaortic stenosis is an uncommon cause of left ventricular outflow tract obstruction. Although its relationship to infective endocarditis is well defined, the expected site of vegetation is over the aortic valve. We report on a 46-year-old man who had a discrete membranous subaortic stenosis, complicated with infective endocarditis, in which the vegetation was over the subaortic membrane and the aortic valve was spared. To our knowledge, this is the first reported case of that entity.

Discrete Membranous Subaortic Stenosis: Improved Results After Resection and Myectomy

Background. Despite an adequate resection, a significant recurrence rate is encountered in patients undergoing operation for discrete membranous subaortic stenosis. The fibrous membrane and hypertrophied myocardium commonly are removed, but because of the involved risks, the resection may be inadequate and contribute to the recurrence rate. Methods. A review of the cases of 23 patients undergoing operation for discrete membranous subaortic stenosis from 1980 to 1994 was undertaken. Fourteen patients (61%) had coexisting cardiac lesions, all of which were concomitantly repaired. Results. The left ventricle–aorta gradient decreased from a preoperative mean of 63.39 ± 7.63 mm Hg to 15.17 ± 3.06 mm Hg postoperatively ( p < .001) during a mean follow-up of 3.32 ± 0.58 years. Aortic insufficiency decreased postoperatively in 8 patients (34.8%), remained unchanged in 6 patients (26.1%), and showed only insignificant progression in 4 patients (17.4%). There were no early deaths, and the single late death was not cardiac related. No patient had development of endocarditis or heart block or required a pacemaker. One patient (4.3%) had a recurrence, which required reoperation. Conclusions. Our results suggest that aggressive myectomy in concert with membrane resection constitutes safe treatment for discrete membranous subaortic stenosis and is associated with low rates of endocarditis, recurrence, and progression of aortic insufficiency.

Surgery for Discrete Subvalvular Aortic Stenosis: Actuarial Survival, Hemodynamic Results, and Acquired Aortic Regurgitation

Discrete membranous subaortic stenosis (DMSS) accounts for 8 to 30% of congenital left ventricular outflow obstruction. The immediate effectiveness of surgical resection of this discrete obstructing membrane has been well documented, but little has appeared regarding late clinical and hemodynamic follow-up. Fifty-three patients with DMSS underwent operation at our institution from 1957 to 1983. Most (78%) were symptomatic, 79% had left ventricular hypertrophy (LVH) by electrocardiogram, and 92% had roentgenographic evidence of cardiomegaly preoperatively. Catheterization revealed a mean preoperative left ventricular-aortic gradient of 89 mm Hg. Twenty-eight patients had associated aortic insufficiency (AI) on the initial aortogram. Seven patients acquired AI in the interim between the first and second preoperative catheterization. Our patients have been followed for up to 12 years postoperatively. There have been 2 early and 3 late deaths. (Actuarial analysis revealed 5- and 10-year survival of 95% and 83%, respectively.) Seventy-one percent of the previously symptomatic patients noted relief of their preoperative complaints, and 45% of those with LVH had a regression in voltage. Cardiomegaly as determined by chest roentgenogram decreased in 45%. The left ventricular-aortic gradient fell to an average of 35 mm Hg a year postoperatively. Surgical treatment of congenital subvalvular aortic stenosis is effective in reducing the preoperative symptoms and the left ventricular-aortic gradient. It appears that DMSS causes AI.

Echocardiographic Diagnosis of a Discrete Membranous Subaortic Stenosis with Aneurysm of the Membrane: A Hitherto Undescribed Entity

A case of echocardiographically-demonstrated congenital aneurysm of the subaortic membrane, confirmed at surgery, is presented. The echocardiographic pattern may create an impression of vegetations of bacterial endocarditis. We were not able to find a similar case in the literature.

Mechanism of early systolic closure of the aortic valve in discrete membranous subaortic stenosis.

The mechanism of the apparent early closure of the aortic valve in patients with discrete membranous subaortic stenosis was studied. Discrete membranous subaortic stenosis was simulated in vitro to assess the fluid dynamic characteristics in the region of the aortic valve that may be responsible for the early closure. In the presence of a simulated fixed membranous subaortic obstruction, early systolic closure of the aortic valve was observed on high-speed motion pictures. Opening and early closure of the valve involved only one of the three aortic leaflets. Closure of the open leaflet was associated with the development of a pronounced pressure drop across the open leaflet caused by a large decrease of pressure in the main stream of flow relative to the pressure in the sinus of Valsalva. The pressure decrease in the main stream of flow resulted from a loss of pressure energy caused by an increase in the kinetic energy of the fluid caused by turbulence. Early systolic closure of the aortic valve in discrete membranous subaortic stenosis, therefore, results from the development of a pressure drop across the open leaflet caused by fluid dynamic factors related to the development of turbulent blood flow distal to the subvalvular obstruction.

Successful surgical repair of subaortic annular aneurysm, discrete membranous subaortic stenosis, and valvular aortic stenosis and incompetence: Case report and review of the literature

The first successful surgical repair of subaortic annular aneurysm associated with discrete subaortic stenosis and valvular aortic stenosis and incompetence is reported. The literature concerning this rare malformation is reviewed, and problems of diagnosis and surgical management are discussed.

Discrete membranous subaortic stenosis. Report of 31 patients, review of the literature, and delineation of management.

The presentation, management, and follow-up of 31 patients with discrete membranous subaortic stenosis (DMSS) is presented. DMSS comprised 16% of 185 patients with congenital left ventricular (LV) obstruction. Only one patient was older than 40 years. The rarity of DMSS in older patients in both our population and in the literature is noted, and possible explanations are discussed. One-quarter of these patients had dyspnea, chest pain, or syncope combined with electrocardiographic left ventricular hypertrophy (LVH) and strain, and these all had peak LV outflow gradients (PSG) greater than 85 mm Hg. One-quarter had neither symptoms nor electrocardiographic abnormalities and all had PSG less than 90 mm Hg. Bacterial endocarditis was found in 13%, and in 13% an immediate family member also had congenital LV obstruction. Following surgical resection (25 patients), 18 were asymptomatic, two had residual fibromuscular obstruction, and four developed new fibromuscular obstruction after from one to six years (leading in one to late sudden death). Thus, even after resection, these patients require continued re-evaluation for residual or new LV obstruction.

Membranous Subaortic Stenosis and Patent Ductus Arteriosus

Six children (five of them girls) each initially had a large patent ductus arteriosus with auscultatory, radiologic, and electrocardiographic findings typical of that lesion. After surgery for the lesion, an ejection-type basal systolic murmur led to detection of discrete membranous subaortic stenosis, which became worse in late childhood. The murmur became louder, the systolic pressure gradient increased from slight to significant, and hypertrophic subaortic stenosis or aortic insufficiency (or both) developed in the older children. Surgical excision of the membrane afforded improvement, except in one patient with the most severe involvement. Because of the unexpected finding of discrete membranous subaortic stenosis in these infants and young children who had undergone surgery for a large patent ductus arteriosus and because of the treacherous worsening of the effects of the discrete membranous subaortic stenosis as childhood progressed, it is important that those patients with a persistent systolic murmur after ductal ligation not be discharged from cardiac follow-up as cured. Serial cardiac catheterization during the growing years appears to be the most accurate way of detecting worsening discrete membranous subaortic stenosis, so that the membrane can be excised before severe complications occur.

Echocardiographic manifestations of discrete subaortic stenosis

The echocardiographic manifestations of discrete membranous subaortic stenosis are described in three cases. The diagnosis was confirmed by cardiac catheterization in all and at operation in two. The characteristic finding in these patients was abnormal movement of the aortic valve leaflets. The leaflets opened rapidly with the onset of systole, then exhibited abrupt premature closure shortly after ventricular ejection. The valve remained partially closed throughout the remainder of systole. This premature leaflet closure Is believed to be caused by obstruction to aortic valve flow produced by the band-like fibrous subaortic tissue. The valve leaflets also exhibited a gross fluttering motion possibly caused by a jet stream effect of the turbulent blood hitting the leaflets. In the two patients treated surgically, postoperative echograms continued to show premature leaflet closure but the degree of closure was decreased. The echocardlogram of one patient had the characteristic systolic anterior bulge of the mitral valve observed in muscular subaortic stenosis or idiopathic hypertrophic subaortic stenosis. Our data suggest that the following echocardiographic findings are suggestive if not specific for discrete subaortic stenosis: aortic valve closure early in systole, persistent valve closure throughout the remainder of systole, coarse fluttering of the leaflets, and absence of asymmetric septal hypertrophy.