A histological study of the atria in patients with isolated rheumatic mitral regurgitation with and without atrial fibrillation.

BACKGROUND: There is a high incidence of atrial fibrillation (AF) in patients with isolated rheumatic mitral regurgitation (MR). The histopathologic changes in the atria of patients with isolated rheumatic MR with and without AF are unknown. OBJECTIVES: We aimed to determine the histological findings in patients with isolated severe rheumatic MR with and without AF. METHODS: Patients with severe isolated rheumatic MR undergoing valve replacement surgeries underwent endocardial biopsies from right atrial appendage, left atrial appendage, right free wall, left free wall, left posterior wall, and mitral valve. Group I consisted of patients in sinus rhythm (SR), and Group II included patients with AF. We analyzed and compared these 10 histological features in the biopsies of patients in Groups I and II. RESULTS: Of the 25 patients, 12 were in Group I and 13 in Group II. In Group I, patients had severe myocyte hypertrophy (60% vs. 18%, p = .04) that was significantly more in the right atrium (22.7% vs. 11.4%, p = .059). Interstitial adipose tissue deposition was more common in Group I (30% vs. 25%, p = .06). Interstitial fibrosis was evenly distributed at all sites without significant difference between the two groups. Group II patients had a higher prevalence and severity of vacuolar degeneration (91% vs. 60%, p = .09). CONCLUSIONS: Patients with isolated severe rheumatic MR and AF have more vacuolar degeneration in the atrial tissue. Patients with SR have myocyte hypertrophy and interstitial adipose tissue deposition. Interstitial fibrosis is uniformly distributed in patients in SR and AF.

Arterialization and anomalous vein wall remodeling in varicose veins is associated with upregulated FoxC2-Dll4 pathway.

Varicose veins of lower extremities are a heritable common disorder. Mechanisms underlying its pathogenesis are still vague. Structural failures such as valve weakness and wall dilatation in saphenous vein result in venous retrograde flow in lower extremities of body. Reflux of blood leads to distal high venous pressure resulting in distended veins. In an earlier study, we observed a positive association between c.-512C>T FoxC2 gene polymorphism and upregulated FoxC2 expression in varicose vein specimens. FoxC2 overexpression in vitro in venous endothelial cells resulted in the elevated mRNA expression of arterial endothelial markers such as Delta-like ligand 4 (Dll4) and Hairy/enhancer-of-split related with YRPW motif protein 2 (Hey2). We hypothesized that an altered FoxC2-Dll4 signaling underlies saphenous vein wall remodeling in patients with varicose veins. Saphenous veins specimens were collected from 22 patients with varicose veins and 20 control subjects who underwent coronary artery bypass grafting. Tissues were processed for paraffin embedding and sections were immunostained for Dll4, Hey2, EphrinB2, α-SMA, Vimentin, and CD31 antigens and examined under microscope. These observations were confirmed by quantitative real-time PCR and western blot analysis. An examination of varicose vein tissue specimens by immunohistochemistry indicated an elevated expression of Notch pathway components, such as Dll4, Hey2, and EphrinB2, and smooth muscle markers, which was further confirmed by gene and protein expression analyses. We conclude that the molecular alterations in Dll4-Hey2 signaling are associated with smooth muscle cell hypertrophy and hyperplasia in varicose veins. Our observations substantiate a significant role for altered FoxC2-Dll4 signaling in structural alterations of saphenous veins in patients with varicose veins.

Forkhead box C2 promoter variant c.-512C>T is associated with increased susceptibility to chronic venous diseases.

Chronic venous disease (CVD) is one of the most prevalent yet underrated disorders worldwide. High heritability estimates of CVD indicate prominent genetic components in its etiology and pathology. Mutations in human forkhead box C2 (FoxC2) gene are strongly associated with valve failure in saphenous and deep veins of lower extremities. We explored the association of genetic variants of FoxC2 as well as FoxC2 mRNA and protein expression levels with CVD of lower limbs. We systematically sequenced the single coding exon, 5' and 3' flanking regions of FoxC2 gene in 754 study subjects which includes 382 patients with CVD and 372 healthy subjects. Four novel and three reported polymorphisms were identified in our cohort. Three variants in 5' flanking region and one in 3' flanking region of FoxC2 gene were significantly associated with CVD risk. FoxC2 mRNA in vein tissues from 22 patients was 4±1.42 fold increased compared to saphenous veins from 20 normal subjects (p<0.01). FoxC2 protein was also significantly upregulated in varicose veins compared to control samples. The c.-512C>T (rs34221221: C>T) variant which is located in the FoxC2 putative promoter region was further analyzed. Functional analysis of c.-512C>T revealed increased mRNA and protein expression in patients with homozygous TT genotype compared to heterozygous CT and wild CC genotypes. Luciferase assay indicated higher transcriptional activity of mutant compared to wild genotype of this variant. These findings suggested that c.-512C>T variant of FoxC2 was strongly associated with susceptibility to CVD and also that this variant resulted in FoxC2 overexpression. To obtain a mechanistic insight into the role of upregulated FoxC2 in varicosities, we overexpressed FoxC2 in venous endothelial cells and observed elevated expression of arterial markers Dll4 and Hey2 and downregulation of venous marker COUP-TFII. Our study indicates altered FoxC2-Notch signaling in saphenous vein wall remodeling in patients with varicose veins.

Acute severe mitral regurgitation following balloon mitral valvotomy: echocardiographic features, operative findings, and outcome in 50 surgical cases.

OBJECTIVE: To analyze the echocardiographic and operative findings with respect to mitral valve anatomy in individuals undergoing emergency surgery for acute severe mitral regurgitation (MR) following balloon mitral valvotomy (BMV). In addition, the clinical profile and outcomes are highlighted. BACKGROUND: Acute severe MR is a major complication of BMV. There are only a few reports which have studied the echocardiographic and operative findings in this setting. In addition, optimal timing of surgery is uncertain. METHODS: Prospective study of 50 consecutive patients undergoing emergency mitral valve replacement (MVR) for acute severe MR following BMV. RESULTS: In 3855 patients who underwent BMV, acute severe MR developed in 50 cases (1.3%) and was referred for emergency MVR. Hypotension (72%), hypoxia (64%), orthopnea (14%), and pulmonary edema (12%) were the clinical manifestations. Severe MR was secondary to anterior mitral leaflet tear in 36 cases (72%), paracommisural tear with annular involvement in seven cases (14%), posterior mitral leaflet tear in five cases (10%) and chordal tear in two cases (4%). The correlation between two-dimensional transthoracic echocardiography (2D-TTE) and operative finding for mitral valve calcification was found to be strong (r = 0.862), in contrast to submitral fusion, where it was found to be moderate (r = 0.536). In-hospital mortality was 12%. Mortality was higher in patients whose time to surgery was ≥24 hr when compared to those who underwent MVR within 24 hr (P < 0.001). CONCLUSIONS: Hypotension and hypoxia are the predominant manifestations of acute severe MR following BMV. Anterior mitral leaflet tear is the most common etiology for severe MR. 2D-TTE underestimated the severity of submitral disease. Early MVR (<24 hr) is recommended for optimal outcome.

Controlling oxygenation during initiation of cardiopulmonary bypass: can it improve immediate postoperative outcomes in cyanotic children undergoing cardiac surgery? A prospective randomized study.

OBJECTIVE: Cardiopulmonary bypass (CPB) initiated with high oxygen levels may expose cyanotic children to reoxygenation injury. The ideal method of initiation of bypass to prevent this phenomenon still remains largely unproven. This study tested the hypothesis that controlling oxygenation during initiation of CPB improves early postoperative outcomes. METHODS: Thirty-one cyanotic children were randomized to two treatment arms of the study. In group A (intervention), CPB was initiated with fraction of inspired oxygen (Fio 2) 0.21, and after one minute of full bypass, Fio 2 was increased at increments of 0.1 per minute to reach 0.6. In group B (hyperoxemic), CPB was initiated using Fio 2 >0.6. Aortic cross clamp time (minutes), CPB time (minutes), creatine phosphokinase-MB (CPK-MB) levels (U/L), lactate levels (mmol/L), duration of ventilator support (hours), inotropic support (hours), and intensive care unit (ICU) stay (hours) as well as hospital mortality were measured. RESULTS: Levels of CPK-MB (group A mean = 59.6 U/L, 95% confidence interval [CI]: 45.9-73.3; group B mean = 82.6 U/L, 95% CI: 66.1-99.1, P = .016) and ventilation time (group A median = 16.5 hours; interquartile range [IQR] = 11.25-23; group B median = 27.5 hours; IQR = 17-54, P = .045) were significantly lower in the intervention group. Other parameters showed no significant differences: CPB time (group A median = 71.5 minutes, IQR = 64-100; group B median = 95.5 minutes, IQR = 58-145, P = .71), cross clamp time (group A mean = 59.2 minutes, 95% CI: 47.6-70.8; group B mean = 66.57 minutes, 95% CI: 47.6-88.5, P =.57), lactate levels (mmol/L; group A median = 1.8, IQR = 1.48-2.59; group B median = 2.1, IQR = 1.29-2.62, P = 1), inotropic support (group A median = 47.5 hours, IQR = 36-73.75; group B median = 59.5 hours, IQR = 41.75-92.5, P = .27), ICU stay (group A median = 59.5 hours, IQR = 48.25-118.5; group B median = 85 hours, IQR = 47.75-137.50, P = .21), and mortality (group A n = 2, group B n = 2). CONCLUSION: A controlled oxygenation protocol was associated with significantly lower postoperative CPK-MB levels. Evaluation of other end points including ventilation times requires a study with larger sample size for validation.

Cardiac tumour in a patient with rheumatic heart disease.

A 45-year-old female known to suffer from rheumatic heart disease (RHD), presented with breathlessness of 1 year duration. Two-dimensional echocardiography revealed significant mitral and aortic valve disease mandating double valve replacement. In addition, an unusual finding in the form of a well-defined, densely calcified intramyocardial left ventricular mass was noted on echocardiography. The nature and extent of the mass was assessed by additional imaging modalities. Patient underwent excision of the mass followed by double valve replacement. Histopathology was consistent with cardiac calcific amorphous tumour (CAT). An unusual occurrence of CAT in a patient with RHD is presented herein. This rare tumour has not been previously described in patients with RHD.