A case of surgically resected cardiac rhabdomyoma with progressive left ventricular outflow tract obstruction.

Cardiac rhabdomyoma is the most prevalent cardiac tumors in the pediatric population, in close association with tuberous sclerosis complex. It is usually detected antenatally or postnatally by echocardiography. Clinical presentations depend greatly on the size and position of the tumor mass. Interestingly, rhabdomyoma has a propensity to regress spontaneously and is not usually operated upon, unless the patient becomes hemodynamically compromised. Herein, we report an unusual case of surgically treated cardiac rhabdomyoma in a baby boy presented at birth with a progressive enlarging intraventricular mass, complicated with left ventricular outflow tract obstruction 7 weeks later. Histopathological examination of the intracardiac mass revealed sheets of tumor cells with spider-like morphology (known as "spider cells"), confirmed the diagnosis of rhabdomyoma. Close disease monitoring of patient's hemodynamic status in a newly diagnosed cardiac rhabdomyoma is inevitable as the tumor, although rare, may progress.

Cardiac AA amyloidosis in a patient with obstructive hypertrophic cardiomyopathy.

Cardiac amyloid A (AA) amyloidosis is rare. We present the case of a 72-year-old woman with obstructive hypertrophic cardiomyopathy (HCM) and biopsy-proven renal AA amyloidosis whose dyspnea and exercise intolerance had worsened over the previous year. Her AA amyloidosis was suspected to be secondary to chronic diverticulitis for which she had undergone hemicolectomy and sigmoidectomy 3 years prior. Echocardiographic findings were consistent with worsening left ventricular outflow tract obstruction at rest. Cardiac magnetic resonance imaging revealed patchy areas of midwall late gadolinium enhancement. Right ventricular endomyocardial biopsy did not reveal amyloid deposition, and cardiac technetium-99m pyrophosphate scintigraphy did not suggest transthyretin amyloidosis. The patient underwent septal myectomy with resection of an accessory papillary muscle. Pathological examination of the myectomy specimen was consistent with HCM. In addition, there was a thick layer of diffuse endocardial and vascular amyloid deposition that was identified as AA type by laser-microdissection with liquid chromatography-coupled tandem-mass spectrometry. This case report highlights the presence of 2 distinct disease processes occurring simultaneously and the importance of tissue diagnosis of AA amyloidosis, a condition that is not commonly associated with HCM.

Primary undifferentiated spindle cell sarcoma obstructing the right ventricular outflow tract.

BACKGROUND: Primary undifferentiated spindle cell sarcoma in the right ventricle is an extremely rare tumor. Radical surgical excision is the optimal treatment for long-term survival due to poor response to chemotherapy or radiotherapy at an advanced stage. CASE PRESENTATION: A 42-year-old man with no previous medical history presented with mild dyspnea on exertion and abdominal distension that lasted a week. Computed tomography (CT) revealed a huge homogeneous mass completely obstructing the right ventricle and extending into the pulmonary trunk. However, he suddenly collapsed the next day while on his way to an echocardiography. An extracorporeal membrane oxygenation (ECMO) device was inserted percutaneously and ECMO support was urgently initiated. Based on consideration of right ventricular outflow tract (RVOT) obstruction in the initial CT scan, we decided to remove the mass from the right ventricle immediately. The main mass was resected to relieve the RVOT obstruction, and after the operation, the ECMO was removed from the operation room. However, the patient failed to regain consciousness and electroencephalography (EEG) and subsequent magnetic resonance imaging (MRI) indicated severe hypoxic brain damage. We assume CPR was unsuccessful because the mass completely blocked the RVOT. Pathology revealed the mass was an undifferentiated spindle cell sarcoma. CONCLUSIONS: We present the case of a 42-year-old male with cardiac arrest due to right ventricular outflow tract obstruction by a tumor of the right ventricle. Surgical resection was performed and in histopathology it was proved to be an undifferentiated spindle cell sarcoma.

Surgery for Left Ventricular Outflow Tract Obstruction with a Relatively Thin Interventricular Septum.

BACKGROUND: To examine the results of myectomy and mitral valve surgery for systolic anterior motion (SAM) of the mitral valve and left ventricular outflow tract obstruction (LVOTO) with a relatively thin interventricular septum. METHODS: The subjects were 12 patients with SAM and LVOTO. Eight had hypertrophic obstructive cardiomyopathy (HOCM) with a mean interventricular septal thickness of 16 mm. Three had sigmoid septum and one had an unknown etiology. For HOCM, isolated extended myectomy was performed when mitral regurgitation was mild (n = 1) and extended myectomy plus mitral valve surgery was performed when mitral regurgitation was more than mild (n = 4) or primary valve etiologies existed (n = 3). Myectomy was performed for the three cases with sigmoid septum. Myectomy plus height reduction of the posterior mitral leaflet was performed for the one case with the unknown etiology of SAM. RESULTS: In the patients with HOCM, the maximum LVOT pressure gradient significantly decreased from 140 ± 18 to 16 ± 6 and 3 ± 3 mm Hg, while mitral regurgitation significantly decreased from 2.3 ± 0.5 to 0.5 ± 0.3 and 0.4 ± 0.2 at pre-op, early post-op, and last follow-up (3 ± 1 years), respectively. In the other etiologies, the maximum LVOT pressure gradient changed from 56 ± 15 to 25 ± 15 and 5 ± 4 mm Hg; mitral regurgitation changed from 2.0 ± 0.6 to 1.3 ± 0.3 and 1.3 ± 0.8, at pre-op, early post-op, and the last follow-up (3 ± 2 years), respectively. CONCLUSION: Myectomy with mitral valve surgery is an option for SAM and LVOTO in patients with a relatively thin interventricular septum.

Balloon Versus Computed Tomography Sizing of the Aortic Annulus for Transcatheter Aortic Valve Replacement and the Impact of Left Ventricular Outflow Tract Calcification and Morphology on Sizing.

OBJECTIVES: To evaluate the role of balloon annular sizing in transcatheter aortic valve replacement (TAVR). BACKGROUND: Multidetector cardiac computed tomography (MDCT) is the gold standard for aortic annular sizing in TAVR. Balloon sizing is increasingly used in patients with borderline annular size and severe calcification. A comparison between these two techniques is needed. METHODS: We retrospectively compared baseline characteristics and 30-day outcomes of patients undergoing balloon-expandable TAVR using annular MDCT or balloon sizing. Paravalvular leak (PVL) rates were compared adjusting for access site, valve generation, size, and valve calcification. RESULTS: A total of 205 patients underwent TAVR with MDCT (n = 110) or balloon sizing (n = 95). Balloon-sized patients were older (83 years vs 81 years; P=.03), had more valve calcification (60.2% vs 30.9%; P<.001), and underwent more minimalist TAVR (61.1% vs 40%; P=.03). Although we found no difference between balloon and MDCT sizing in rates of acute renal failure (3.2% vs 0.9%; P=.34), annular rupture (1.1% vs 1.8%; P>.99), ≥ mild PVL by angiography (40% vs 35.5%; P=.57), or 30-day transthoracic echocardiography (40.7% vs 29.3%; P=.78), balloon-sized patients had a higher aortic regurgitation index (≥25) of 74.4% vs 54.1% (P=.01). Thirty-day rates of ≥ moderate PVL were 7.0% with balloon and 5.7% with MDCT sizing (P=.34). Balloon sizing recommended a different valve size in 34.0% of patients who underwent both methods (n = 50). A different recommendation occurred more often in patients with moderate/severe annular calcification (50.0% vs 33.3%; P=.01) and non-tubular left ventricular outflow tracts (LVOTs) (70.6% vs 30.3%; P=.01). CONCLUSION: Balloon sizing can be a complement to MDCT for annular sizing in TAVR, especially in patients with moderate/severe annular calcification, borderline annular size, and non-tubular LVOT.

Left Ventricular Outflow Tract Obstruction in Hypertrophic Cardiomyopathy Patients Without Severe Septal Hypertrophy: Implications of Mitral Valve and Papillary Muscle Abnormalities Assessed Using Cardiac Magnetic Resonance and Echocardiography.

BACKGROUND: In patients with hypertrophic cardiomyopathy and left ventricular outflow tract (LVOT) obstruction, but without basal septal hypertrophy, we sought to identify mitral valve (MV) and papillary muscle (PM) abnormalities that predisposed to LVOT obstruction, using echo and cardiac magnetic resonance. METHODS AND RESULTS: We studied 121 patients with hypertrophic cardiomyopathy hypertrophic cardiomyopathy (age, 49±17 years; 60% men; 57% on ß-blockers) with a basal septal thickness of ≤1.8 cm who underwent echocardiography (rest+stress) and cine cardiac magnetic resonance. Echo measurements included maximal LVOT gradient (rest/provocable), MV leaflet length (parasternal long, 4 and 3-chamber views), and abnormal chordal attachment to mid/base of anterior MV. Cine cardiac magnetic resonance measurements included basal septal thickness, number/area of PM heads, and bifid PM mobility (in systole and diastole). Mean basal septal thickness, LVOT gradient, and LV ejection fraction were 1.5±0.3 cm, 72±54 mm Hg, and 61±6%, respectively. The number of anterolateral and posteromedial PM heads was 2.7±0.7 and 2.6±0.7, respectively. Anterolateral and posteromedial PM areas were 19.9±7 cm(2) and 17.1±6 cm(2), respectively. PM mobility was 11±6°. On multivariable analysis, predictors of maximal LVOT gradient were basal septal thickness, bifid PM mobility, anterior mitral leaflet length, and abnormal chordal attachment to base of anterior mitral leaflet. Forty-five patients underwent surgery to relieve LVOT obstruction, of which 52% needed an additional nonmyectomy (MV repair/replacement or PM reorientation) approach. CONCLUSIONS: In hypertrophic cardiomyopathy patients without significant LV hypertrophy, in addition to basal septal thickness, anterior MV length, abnormal chordal attachment, and bifid PM mobility are associated with LVOT obstruction. In such patients, additional procedures on MV and PM (±myectomy) could be considered.

Cell Junction Pathology of Neural Stem Cells Is Associated With Ventricular Zone Disruption, Hydrocephalus, and Abnormal Neurogenesis.

Fetal-onset hydrocephalus affects 1 to 3 per 1,000 live births. It is not only a disorder of cerebrospinal fluid dynamics but also a brain disorder that corrective surgery does not ameliorate. We hypothesized that cell junction abnormalities of neural stem cells (NSCs) lead to the inseparable phenomena of fetal-onset hydrocephalus and abnormal neurogenesis. We used bromodeoxyuridine labeling, immunocytochemistry, electron microscopy, and cell culture to study the telencephalon of hydrocephalic HTx rats and correlated our findings with those in human hydrocephalic and nonhydrocephalic human fetal brains (n = 12 each). Our results suggest that abnormal expression of the intercellular junction proteins N-cadherin and connexin-43 in NSC leads to 1) disruption of the ventricular and subventricular zones, loss of NSCs and neural progenitor cells; and 2) abnormalities in neurogenesis such as periventricular heterotopias and abnormal neuroblast migration. In HTx rats, the disrupted NSC and progenitor cells are shed into the cerebrospinal fluid and can be grown into neurospheres that display intercellular junction abnormalities similar to those of NSC of the disrupted ventricular zone; nevertheless, they maintain their potential for differentiating into neurons and glia. These NSCs can be used to investigate cellular and molecular mechanisms underlying this condition, thereby opening the avenue for stem cell therapy.

A giant myxoma originating from the aortic valve causing severe left ventricular tract obstruction: a case report and literature review.

INTRODUCTION: The left ventricular localization of a myxoma is very rare, usually arising from the interventricular septum close to the left ventricular outflow tract, the mitral valve, the ventricular wall and extremely rarely the aortic valve. CASE PRESENTATION: A 13-year-old male was admitted due to dyspnea and angina. Transesophageal echocardiography revealed left ventricular outflow tract obstruction with a mean gradient of 58 mmHg, and a mobile mass measuring 65×25 mm originating from the ventricular surface of the aortic valve was identified. The patient underwent urgent surgical excision and aortic valve replacement. Histopathological examination of the mass confirmed the diagnosis of a myxoma. CONCLUSION: In conclusion, a myxoma originating from the aortic valve remains a very rare localization. Total resection associated with aortic valve replacement seems to offer an excellent outcome.

Association of noninvasively measured left ventricular mechanics with in vitro muscle contractile performance: a prospective study in hypertrophic cardiomyopathy patients.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is a primary myopathic process in which regional left ventricular dysfunction may exist without overt global left ventricular dysfunction. In obstructive HCM patients who underwent surgical myectomy (SM), we sought to determine if there is a significant association between echocardiographic longitudinal strain, histopathology, and in vitro myocardial performance (resting tension and developed tension) of the surgical specimen. METHODS AND RESULTS: HCM patients (n=122, 54±14 years, 54% men) undergoing SM were prospectively recruited. Longitudinal systolic strain and diastolic strain rates were measured at that basal septum (partially removed at SM) by using velocity vector imaging on preoperative echocardiography. Semiquantitative histopathologic grading of myocyte disarray and fibrosis and in vitro measurements of resting tension and developed tension were made in septal tissue obtained at SM. Mean basal septal systolic strain and diastolic strain rate were -8.3±5% and 0.62±0.4/s, while mild or greater degree of myocyte disarray and interstitial fibrosis were present in 85% and 87%, respectively. Mean resting tension and developed tension were 2.8±1 and 1.4±0.8 g/mm(2). On regression analysis, basal septal systolic strain, diastolic strain rate, disarray, and fibrosis were associated with developed tension (ß=0.19, 0.20, -0.33, and -0.40, respectively, all P<0.01) and resting tension (ß=0.21, 0.22, -0.25, and -0.28, respectively, all P<0.01). CONCLUSION: In obstructive HCM patients who underwent SM, left ventricular mechanics (echocardiographic longitudinal systolic strain and diastolic strain rates), assessed at the basal septum (myocardium removed during myectomy) and histopathologic findings characteristic for HCM (disarray and fibrosis) were significantly associated with in vitro myocardial resting and developed contractile performance.

Large cardiac tumor managed with resection and two ventricular assist devices.

Symptomatic cardiac tumors can lead to a rapid clinical deterioration and death. Prompt surgical resection is ideal in this situation as it is the only proven treatment to date. We report the radical resection of a large malignant cardiac tumor that obstructed the right ventricular outflow tract. Extensive resection precluded reconstruction and limited the ability to implant a total artificial heart; thus, 2 paracorporeal devices were implanted instead.

Which cardiovascular magnetic resonance planes and sequences provide accurate measurements of branch pulmonary artery size in children with right ventricular outflow tract obstruction?

Children with right ventricular outflow tract obstructive (RVOTO) lesions require precise quantification of pulmonary artery (PA) size for proper management of branch PA stenosis. We aimed to determine which cardiovascular magnetic resonance (CMR) sequences and planes correlated best with cardiac catheterization and surgical measurements of branch PA size. Fifty-five children with RVOTO lesions and biventricular circulation underwent CMR prior to; either cardiac catheterization (n = 30) or surgery (n = 25) within a 6 month time frame. CMR sequences included axial black blood, axial, coronal oblique and sagittal oblique cine balanced steady-state free precession (bSSFP), and contrast-enhanced magnetic resonance angiography (MRA) with multiplanar reformatting in axial, coronal oblique, sagittal oblique, and cross-sectional planes. Maximal branch PA and stenosis (if present) diameter were measured. Comparisons of PA size on CMR were made to reference methods: (1) catheterization measurements performed in the anteroposterior plane at maximal expansion, and (2) surgical measurement obtained from a maximal diameter sound which could pass through the lumen. The mean differences (Δ) and intra class correlation (ICC) were used to determine agreement between different modalities. CMR branch PA measurements were compared to the corresponding cardiac catheterization measurements in 30 children (7.6 ± 5.6 years). Reformatted MRA showed better agreement for branch PA measurement (ICC > 0.8) than black blood (ICC 0.4-0.6) and cine sequences (ICC 0.6-0.8). Coronal oblique MRA and maximal cross sectional MRA provided the best correlation of right PA (RPA) size with ICC of 0.9 (Δ -0.1 ± 2.1 mm and Δ 0.5 ± 2.1 mm). Maximal cross sectional MRA and sagittal oblique MRA provided the best correlate of left PA (LPA) size (Δ 0.1 ± 2.4 and Δ -0.7 ± 2.4 mm). For stenoses, the best correlations were from coronal oblique MRA of right pulmonary artery (RPA) (Δ -0.2 ± 0.8 mm, ICC 0.9) and sagittal oblique MRA of left pulmonary artery (LPA) (Δ 0.2 ± 1.1 mm, ICC 0.9). CMR PA measurements were compared to surgical measurements in 25 children (5.4 ± 4.8 years). All MRI sequences demonstrated good agreement (ICC > 0.8) with the best (ICC 0.9) from axial cine bSSFP for both RPA and LPA. Maximal cross sectional and angulated oblique reformatted MRA provide the best correlation to catheterization for measurement of branch PA's and stenosis diameter. This is likely due to similar angiographic methods based on reformatting techniques that transect the central axis of the arteries. Axial cine bSSFP CMR was the best surgically measured correlate of PA branch size due to this being a measure of stretched diameter. Knowledge of these differences provides more precise PA measurements and may aid catheter or surgical interventions for RVOTO lesions.

Bmp signaling represses Vegfa to promote outflow tract cushion development.

Congenital heart disease (CHD) is a devastating anomaly that affects ∼1% of live births. Defects of the outflow tract (OFT) make up a large percentage of human CHD. We investigated Bmp signaling in mouse OFT development by conditionally deleting both Bmp4 and Bmp7 in the second heart field (SHF). SHF Bmp4/7 deficiency resulted in defective epithelial to mesenchymal transition (EMT) and reduced cardiac neural crest ingress, with resultant persistent truncus arteriosus. Using a candidate gene approach, we found that Vegfa was upregulated in the Bmp4/7 mutant hearts. To determine if Vegfa is a downstream Bmp effector during EMT, we examined whether Vegfa is transcriptionally regulated by the Bmp receptor-regulated Smad. Our findings indicate that Smad directly binds to Vegfa chromatin and represses Vegfa transcriptional activity. We also found that Vegfa is a direct target for the miR-17-92 cluster, which is also regulated by Bmp signaling in the SHF. Deletion of miR-17-92 reveals similar phenotypes to Bmp4/7 SHF deletion. To directly address the function of Vegfa repression in Bmp-mediated EMT, we performed ex vivo explant cultures from Bmp4/7 and miR-17-92 mutant hearts. EMT was defective in explants from the Bmp4/7 double conditional knockout (dCKO; Mef2c-Cre;Bmp4/7(f/f)) and miR-17-92 null. By antagonizing Vegfa activity in explants, EMT was rescued in Bmp4/7 dCKO and miR-17-92 null culture. Moreover, overexpression of miR-17-92 partially suppressed the EMT defect in Bmp4/7 mutant embryos. Our study reveals that Vegfa levels in the OFT are tightly controlled by Smad- and microRNA-dependent pathways to modulate OFT development.

Supravalvar aortic stenosis: current surgical approaches and outcomes.

Supravalvar aortic stenosis (SVAS) is a congenital anomaly characterized by a discrete or diffuse narrowing of the ascending aorta. It may also be associated with right-ventricular outflow tract obstruction, aortic valve pathology and coronary ostial stenosis. While present in both familial and sporadic forms, it demonstrates a strong association with William-Beuren syndrome, both being anomalies associated with defects in the elastin gene. In this article, the authors have discussed the etiology, morphology, clinical presentation and genetic basis of SVAS. Various surgical approaches, both conventional and recent, have been discussed and demonstrated with the aid of diagrams. Single-, two- and three-sinus methods have been presented, along with a comparative analysis of early results, associated procedures, late mortality and reoperation. In conclusion, the authors have described their institutional experience of more than 40 years in the surgical management of SVAS.

Anatomical factors determining surgical decision-making in patients with transposition of the great arteries with left ventricular outflow tract obstruction.

OBJECTIVES: Transposition of the great arteries (TGA) and left ventricular outflow tract obstruction (LVOTO) with or without ventricular septal defect have multiple surgical treatment options. We sought to identify pre- and intraoperative factors that determine the timing of repair, procedure type and subsequent LVOT outcome. METHODS: Twenty-eight (8.2% of all TGA) patients with TGA with LVOTO (double outlet ventricle, n = 5, TGA/intact septum, n = 1) between 2000 and 2012 were reviewed. Anatomical factors were identified by prerepair echocardiography. LVOTO complexity was characterized by the degree of obstruction (0 = none, 0.33 = mild, 0.66 moderate and 1 = severe) at various levels: pulmonary valve (PV) dysplasia/hypoplasia, posterior deviation of the infundibular septum, fibromuscular ridge, tissue tag and abnormal chordal attachment. Summation of the obstruction score, at each level, yielded the LVOT complexity score. The descriptive analysis of intraoperative decision-making at late repair was performed. OPERATIONS: early arterial switch operation (ASO) + LVOT resection (n = 9, 32%), late ASO + LVOT resection (n = 3, 10%), Nikaidoh (n = 8, 29%), Rastelli (n = 6, 21%), single-ventricle palliation (n = 2, 7%). The primary LVOT obstruction mechanism was posterior deviation of the infundibular septum (n = 16, 57%) and PV dysplasia (n = 6, 21%). The early ASO group had a lower PV complexity score (0.42 ± 0.22 vs 0.96 ± 0.55, P = 0.007), tissue tag score (0.03 ± 0.15 vs 0.26 ± 0.34, P = 0.018) and LVOT complexity score (2.11 ± 0.86 vs 3.2 ± 0.96, P = 0.006). The LVOT complexity score in the Nikaidoh group was higher than in the late ASO group (P = 0.019). Of 16 candidates for the Nikaidoh procedure, 6 patients underwent a Rastelli operation due to coronary artery patterns (single coronary, n = 3, 1RL-2Cx, n = 2 or an abnormal left anterior descending coronary artery course, n = 1). Two patients underwent single-ventricle palliation due to the interference of essential chordae. All patients survived the operation. The 3-year survival was 96%. One patient who underwent late ASO required re-LVOT resection. CONCLUSIONS: A newly developed scoring system, the LVOT complexity score, helped to quantify the LVOT complexity and was correlated with our choice of the surgical procedure of TGA with LVOTO. The current strategy achieved reasonable survival and LVOT outcome with three quarters of the patients having an anatomically aligned LVOT. The coronary anatomy pattern was the primary determinant in the decision-making between the Nikaidoh procedure and the Rastelli operation.