Long-Term Outcomes of Patients With Mediastinal Radiation-Associated Severe Aortic Stenosis and Subsequent Surgical Aortic Valve Replacement: A Matched Cohort Study

BACKGROUND

Cardiac disease after mediastinal radiotherapy for thoracic malignancy (chest radiotherapy [XRT]) often manifests as progressive aortic stenosis. In patients with XRT-induced severe aortic stenosis undergoing surgical aortic valve replacement (SAVR), we sought to: (1) study long-term survival and compare these patients with a matched cohort undergoing SAVR during the same time frame; and (2) identify potential predictors of long-term mortality.

METHODS AND RESULTS

We studied patients with symptomatic severe aortic stenosis undergoing SAVR at our institution, of which there were 172 mediastinal XRT patients (63±13 years, 62% women) matched in a 1:1 fashion (based on age, sex, time of surgery, and aortic valve area) with 172 non-XRT patients (comparison group). Baseline clinical and postoperative data were obtained. Society of Thoracic Surgeons score was calculated and mortality was recorded. In the XRT group, the median Society of Thoracic Surgeons score was 4% (interquartile range 2-13), while mean left ventricular ejection fraction, left ventricular stroke volume index, and mean aortic valve gradient were 54±11%, 38±14 mL/m2, and 39±11 mm Hg, respectively. In the entire cohort, 27% and 34% of patients underwent concomitant coronary artery bypass grafting and aortic surgery at the time of SAVR, respectively. Thirty-day/in-hospital deaths occurred in 4 (2%) patients in the XRT group and 0 patients in the comparison group. At 6±3 years of follow-up, on matched group analysis, there were 95 (28%) deaths (83 [48%] in the XRT group versus 12 [7%] in the comparison group (log-rank 89, P<0.001). On multivariable Cox survival analysis, in the whole cohort, higher Society of Thoracic Surgeons score (hazard ratio, 1.14; 95% CI, 1.03-1.26) and mediastinal XRT (hazard ratio, 8.12; 95% CI, 4.26-15.64) were associated with increased longer-term mortality (both P<0.01).

CONCLUSIONS

In patients with severe aortic stenosis undergoing SAVR, patients with prior mediastinal XRT have significantly worse longer-term survival versus a matched cohort.

The Role of Stress Echocardiography in Valvular Heart Disease: A Current Appraisal

Stress echocardiography is a widely available, safe, low-cost, versatile imaging modality which is becoming increasingly recognized as a valuable tool in the assessment of patients with native and prosthetic left-sided valvular heart disease. It provides a quantitative assessment to help guide clinical decision-making when discordance exists between symptoms and severity of valve disease. Exercise (treadmill or bicycle) remains the preferred stress modality, but pharmacological augmentation with dobutamine can be used if needed. Low-dose dobutamine stress echocardiography is specifically valuable in patients with low-flow, low-gradient aortic stenosis when attempting to differentiate true severe aortic stenosis from pseudo-severe aortic stenosis. Stress echocardiography not only identifies high-risk features that indicate need for earlier surgery, it also provides useful information for the peri- and postoperative period, including long-term outcome, risk stratification to guide monitoring frequency, and offers guidance for eligibility in competitive sports participation. As research continues to expand the utility of stress echocardiography in the management of patients with valvular heart disease, future research should focus on the recognition of newer parameters identifying high-risk features including subsequent validation in a large population.

Fibronectin fibrils regulate TGF-β1-induced Epithelial-Mesenchymal Transition

Epithelial-Mesenchymal Transition (EMT) is a dynamic process through which epithelial cells transdifferentiate from an epithelial phenotype into a mesenchymal phenotype. Previous studies have demonstrated that both mechanical signaling and soluble growth factor signaling facilitate this process. One possible point of integration for mechanical and growth factor signaling is the extracellular matrix. Here we investigate the role of the extracellular matrix (ECM) protein fibronectin (FN) in this process. We demonstrate that inhibition of FN fibrillogenesis blocks activation of the Transforming Growth Factor-Beta (TGF-β) signaling pathway via Smad2 signaling, decreases cell migration and ultimately leads to inhibition of EMT. Results show that soluble FN, FN fibrils, or increased contractile forces are insufficient to independently induce EMT. We further demonstrate that inhibition of latent TGF-β1 binding to FN fibrils via either a monoclonal blocking antibody against the growth factor binding domain of FN or through use of a FN deletion mutant that lacks the growth factor binding domains of FN blocks EMT progression, indicating a novel role for FN in EMT in which the assembly of FN fibrils serves to localize TGF-β1 signaling to drive EMT.

Aortic Cross-Sectional Area/Height Ratio and Outcomes in Patients With a Trileaflet Aortic Valve and a Dilated Aorta

BACKGROUND

In patients with a dilated proximal ascending aorta and trileaflet aortic valve, we aimed to assess (1) factors independently associated with increased long-term mortality and (2) the incremental prognostic utility of indexing aortic root to patient height.

METHODS

We studied consecutive patients with a dilated aortic root (≥4 cm) that underwent echocardiography and gated contrast-enhanced thoracic aortic computed tomography or magnetic resonance angiography between 2003 and 2007. A ratio of aortic root area over height was calculated (cm²/m) on tomography, and a cutoff of 10 cm²/m was chosen as abnormal, on the basis of previous reports. All-cause death was recorded.

RESULTS

The cohort comprised 771 patients (63 years [interquartile range, 53-71], 87% men, 85% hypertension, 51% hyperlipidemia, 56% smokers). Inherited aortopathies, moderate to severe aortic regurgitation, and severe aortic stenosis were seen in 7%, 18%, and 2%, whereas 91% and 54% were on β-blockers and angiotensin-converting enzyme inhibitors, respectively. Aortic root area/height ratio was ≥10 cm²/m in 24%. The Society of Thoracic Surgeons score and right ventricular systolic pressure were 3.3±3 and 31±7 mm Hg, respectively. At 7.8 years (interquartile range, 6.6-8.9), 280 (36%) patients underwent aortic surgery (76% within 1 year) and 130 (17%) died (1% in-hospital postoperative mortality). A lower proportion of patients in the surgical (versus nonsurgical) group died (13% versus 19%, P<0.01). On multivariable Cox proportional hazard analysis, aortic root area/height ratio (hazard ratio, 4.04; 95% confidence interval [CI], 2.69-6.231) was associated with death, whereas aortic surgery (hazard ratio, 0.47; 95% CI, 0.27-0.81) was associated with improved survival (both P<0.01). For longer-term mortality, the addition of aortic root area/height ratio ≥10 cm²/m to a clinical model (Society of Thoracic Surgeons score, inherited aortopathies, hypertension, hyperlipidemia, medications, aortic regurgitation, and right ventricular systolic pressure), increased the c-statistic from 0.57 (95% CI, 0.35-0.77) to 0.65 (95% CI, 0.52-0.73) and net reclassification index from 0.17 (95% CI, 0.02-0.31) to 0.23 (95% CI, 0.04-0.34), both P<0.01. Of the 327 patients with aortic root diameter between 4.5 and 5.5 cm, 44% had an abnormal aortic root area/height ratio, of which 78% died.

CONCLUSIONS

In patients with dilated aortic root and trileaflet aortic valve, a ratio of aortic root area to height provides independent and improved stratification for prediction of death.

Relation of Echocardiographic Characteristics of the Right-Sided Heart With Incident Heart Failure and Mortality in Patients With Sleep-Disordered Breathing and Preserved Left Ventricular Ejection Fraction

Sleep-disordered breathing (SDB) has been associated with right-sided heart dysfunction and adverse cardiovascular outcomes. Longitudinal data are sparse in terms of understanding the prognostic implications of right ventricular remodeling in SDB on cardiovascular risk. We therefore investigated the predictive value of right-sided cardiac functional alterations on incident heart failure (HF) or death in SDB. Patients with SDB who underwent echocardiography within 1 month of index polysomnogram from January 2002 to July 2011 with normal left ventricular ejection fraction were included. Cox proportional prognostic hazard models predicting HF or death were used. Of a potential 375 subjects, 202 fulfilled the inclusion criteria (58 ± 14 years; 50% men). Subjects were followed for 3.1 ± 2.4 years with a total of 34 (16.8%) developing HF or death. Right ventricular end-systolic area (hazard ratio [HR] 1.3, 95% CI 1.01 to 1.6, p = 0.038), pulmonary vascular resistance (PVR; HR 1.4, 95% CI 1.1 to 1.7, p = 0.005) and also left atrial volume index (HR 1.7, 95%, CI 1.3 to 2.3, p <0.001) and E/A ratio (HR 1.4, 95% CI 1.1 to 1.7, p <0.001), were predictive of HF or death. Patients with increased PVR had significantly shorter event-free survival than without increased PVR (p = 0.04). In sequential Cox models, a model based on clinical data and left ventricular ejection fraction (χ², 5.4) was improved by left atrial volume index (χ², 12.7; p = 0.011) and further increased by PVR (χ², 19.7; p = 0.015). In conclusion, right-sided heart dysfunction provides important prognostic information in SDB and may aid in identifying those at highest risk to target for closer follow-up.

Predictors and Prognostic Impact of Progressive Ischemic Mitral Regurgitation in Patients With Advanced Ischemic Cardiomyopathy

Background—

Ischemic mitral regurgitation (IMR) is associated with poor outcomes. It is unknown what factors contribute to progression of IMR and how progressive IMR affects outcomes. We sought to determine imaging predictors of IMR progression and to determine if progressive IMR is an independent predictor of survival in patients with advanced ischemic cardiomyopathy.

Methods and Results—

Consecutive advanced ischemic cardiomyopathy patients who underwent cardiac magnetic resonance and echocardiograms at baseline with echocardiographic follow-up were studied. Cardiac magnetic resonance was used to assess left ventricular volumes, infarct size, and mitral valve geometry. The effective regurgitant orifice area (EROA) was calculated from the proximal isovelocity surface area by echocardiography. Repeated measures mixed effects and Cox proportional hazards regression models were built to identify predictors of IMR progression and survival. We evaluated 336 patients (age, 62±11 years) over a median follow-up time of 54 months: 154 patients were subsequently revascularized, and 182 patients were medically treated. Ninety-eight patients (29%) demonstrated an increase in EROA values of ≥0.1 cm 2 . There were 87 adverse events (death or transplant). On multivariable analysis, infarct size ( P <0.001), progression in IMR ( P =0.008), age ( P =0.003), and baseline EROA ( P =0.010) were independently associated with adverse events. Independent predictors of IMR progression were as follows: baseline EROA ( P <0.001), left ventricular end–systolic volume index ( P =0.014), and total scar ( P =0.036).

Conclusions—

IMR frequently increases in severity, and progression is independently associated with adverse left ventricular remodeling and infarct size, as assessed by cardiac magnetic resonance. Furthermore, IMR progression is a powerful independent predictor of adverse events, even after controlling for the severity of IMR at baseline.

Synergistic Utility of Brain Natriuretic Peptide and Left Ventricular Global Longitudinal Strain in Asymptomatic Patients With Significant Primary Mitral Regurgitation and Preserved Systolic Function Undergoing Mitral Valve Surgery

Background—

In asymptomatic patients with ≥3+ mitral regurgitation and preserved left ventricular (LV) ejection fraction who underwent mitral valve surgery, we sought to discover whether baseline LV global longitudinal strain (LV-GLS) and brain natriuretic peptide provided incremental prognostic utility.

Methods and Results—

Four hundred and forty-eight asymptomatic patients (61±12 years and 69% men) with ≥3+ primary mitral regurgitation and preserved left ventricular ejection fraction, who underwent mitral valve surgery (92% repair) at our center between 2005 and 2008, were studied. Baseline clinical and echocardiographic data (including LV-GLS using Velocity Vector Imaging, Siemens, PA) were recorded. The Society of Thoracic Surgeons score was calculated. The primary outcome was death. Mean Society of Thoracic Surgeons score, left ventricular ejection fraction, mitral effective regurgitant orifice, indexed LV end-diastolic volume, and right ventricular systolic pressure were 4±1%, 62±3%, 0.55±0.2 cm 2 , 58±13 cc/m 2 , and 37±15 mm Hg, respectively. Forty-five percent of patients had flail. Median log-transformed BNP and LV-GLS were 4.04 (absolute brain natriuretic peptide: 60 pg/dL) and −20.7%. At 7.7±2 years, death occurred in 41 patients (9%; 0% at 30 days). On Cox analysis, a higher Society of Thoracic Surgeons score (hazard ratio 1.55), higher baseline right ventricular systolic pressure (hazard ratio 1.11), more abnormal LV-GLS (hazard ratio 1.17), and higher median log-transformed BNP (hazard ratio 2.26) were associated with worse longer-term survival (all P <0.01). Addition of LV-GLS and median log-transformed BNP to a clinical model (Society of Thoracic Surgeons score and baseline right ventricular systolic pressure) provided incremental prognostic utility (χ 2 for longer-term mortality increased from 31–47 to 61; P <0.001).

Conclusions—

In asymptomatic patients with significant primary mitral regurgitation and preserved left ventricular ejection fraction who underwent mitral valve surgery, brain natriuretic peptide and LV-GLS provided synergistic risk stratification, independent of established factors.

Predictors of Long-Term Outcomes in Asymptomatic Patients With Severe Aortic Stenosis and Preserved Left Ventricular Systolic Function Undergoing Exercise Echocardiography

Background—

In asymptomatic patients with severe aortic stenosis and preserved left ventricular ejection fraction, we sought to assess incremental prognostic utility of exercise stress echocardiography.

Methods and Results—

We studied 533 such patients (age, 66±13 years; 78% men; 31% with coronary artery disease) who underwent exercise stress echocardiography between 2001 and 2012. Clinical, echocardiographic, and exercise variables (metabolic equivalents [METs], % of age–sex–predicted METs and heart rate recovery at first minute post exercise) were recorded. The end point was all-cause mortality. The Society of Thoracic Surgeons score, left ventricular ejection fraction, mean resting aortic valve (AV) gradient, indexed AV area, METs, and heart rate recovery were 2.9±3%, 58±4%, 35±11 mm Hg, 0.47±0.1 cm 2 /m 2 , 7.8±3, and 26±12 bpm, respectively. Only 50% achieved >100%, whereas 26% achieved <85% age–sex–predicted METs. There were no major exercise stress echocardiography-related complications. Over 6.9±3 years, 341 (64%) underwent AV replacement (54% isolated), and there were 104 (20%) deaths. On multivariable Cox proportional hazard survival analysis, a higher Society of Thoracic Surgeons score (hazard ratio, 1.21), lower % age–sex–predicted METs (hazard ratio 1.15), and slower heart rate recovery (hazard ratio, 1.22) were associated with higher longer-term mortality, whereas AV replacement (time-dependent covariate, hazard ratio, 0.26) was associated with improved survival. The addition of % age–sex–predicted METs to the Society of Thoracic Surgeons score resulted in significant reclassification of longer-term mortality risk (integrated discrimination index, 0.07 [0.03–0.11; P <0.001).

Conclusions—

In asymptomatic patients with severe aortic stenosis and preserved left ventricular ejection fraction undergoing exercise stress echocardiography, a lower % of age–sex–predicted METs and slower heart rate recovery were associated with longer-term mortality, whereas AV replacement was associated with improved survival.

Long-Term Mortality in Patients With Radiation-Associated Coronary Artery Disease Treated With Percutaneous Coronary Intervention

Background—

The incidence and predictors of long-term mortality after percutaneous coronary intervention (PCI) for radiation-associated coronary artery disease are unknown.

Methods and Results—

In this observational study of 314 patients (age, 65.2±11.4 years; 233 [74%] women) treated with PCI, 157 patients with previous external beam radiation therapy (XRT) were matched 1:1 with 157 comparison patients with atherosclerotic coronary artery disease without previous XRT, based on age, sex, lesion artery, and PCI type. The primary end point was all-cause mortality, and the secondary end point was cardiovascular mortality. After follow-up of 6.6±5.5 years, there were 101 deaths; 59 in the XRT group and 42 in the comparison group ( P =0.04). On Cox proportional hazards multivariable survival analysis, previous XRT remained an independent predictor of all-cause mortality (hazard ratio [HR] 1.85; 95% confidence interval [CI], 1.21–2.85; P =0.004) and cardiovascular mortality (HR, 1.70; 95% CI, 1.06–2.89; P =0.03). Additional independent predictors of increased all-cause mortality included balloon angioplasty or bare-metal stent placement compared with drug-eluting stent placement (HR, 2.50; 95% CI, 1.61–3.97; P <0.0001), SYNTAX (Synergy Between PCI With Taxus and Cardiac Surgery) score of ≥11 (the sample median; HR, 1.99; 95% CI, 1.32–3.04; P <0.001), New York Heart Association functional class ≥3 (HR, 1.83; 95% CI, 1.15–2.91; P =0.012), history of smoking (HR, 1.88; 95% CI, 1.10–3.09; P =0.022), and age ≥65 years (HR, 1.70; 95% CI, 1.07–2.07; P =0.024).

Conclusions—

Compared with patients with typical atherosclerotic coronary artery disease, patients with radiation-associated coronary artery disease are at higher risk for mortality after PCI. Previous XRT exposure is independently associated with increased all-cause and cardiovascular mortality in patients treated with PCI.

Anaplasma phagocytophilum Rab10-dependent parasitism of the trans-Golgi network is critical for completion of the infection cycle

Anaplasma phagocytophilum is an emerging human pathogen and obligate intracellular bacterium. It inhabits a host cell-derived vacuole and cycles between replicative reticulate cell (RC) and infectious dense-cored (DC) morphotypes. Host-pathogen interactions that are critical for RC-to-DC conversion are undefined. We previously reported that A. phagocytophilum recruits green fluorescent protein (GFP)-tagged Rab10, a GTPase that directs exocytic traffic from the sphingolipid-rich trans-Golgi network (TGN) to its vacuole in a guanine nucleotide-independent manner. Here, we demonstrate that endogenous Rab10-positive TGN vesicles are not only routed to but also delivered into the A. phagocytophilum-occupied vacuole (ApV). Consistent with this finding, A. phagocytophilum incorporates sphingolipids while intracellular and retains them when naturally released from host cells. TGN vesicle delivery into the ApV is Rab10 dependent, up-regulates expression of the DC-specific marker, APH1235, and is critical for the production of infectious progeny. The A. phagocytophilum surface protein, uridine monophosphate kinase, was identified as a guanine nucleotide-independent, Rab10-specific ligand. These data delineate why Rab10 is important for the A. phagocytophilum infection cycle and expand the understanding of the benefits that exploiting host cell membrane traffic affords intracellular bacterial pathogens.

Prognostic Utility of Brain Natriuretic Peptide in Asymptomatic Patients With Significant Mitral Regurgitation and Preserved Left Ventricular Ejection Fraction

We sought to study the prognostic utility of serum brain natriuretic peptide (BNP) in patients with significant primary mitral regurgitation (MR) and preserved left ventricular (LV) ejection fraction (EF). Consecutive 548 asymptomatic patients (age 62 ± 13 years and 66% men) with ≥ 3 + primary MR and preserved LVEF on echo at rest, evaluated at our center from 2005 to 2008 were studied. Baseline clinical and echo data were recorded and the Society of Thoracic Surgeons (STS) score was calculated. Mean STS score was 4 ± 1%. Mean LVEF, mitral effective regurgitant orifice, indexed LV end-systolic diameter, and right ventricular systolic pressure (RVSP) were 62 ± 4%, 0.55 ± 0.3 cm(2), 1.6 ± 0.3 cm/m(2), and 38 ± 15 mm Hg; 43% had flail. Median log-transformed brain natriuretic peptide (lnBNP) was 4.1 (interquartile range 3.30 to 5.0), corresponding to an absolute BNP value of 60 pg/ml (only 13% had an absolute BNP value >250 pg/ml). At 7.4 ± 2 years, 493 patients (90%) had mitral surgery (92% repair) and nonmalignancy death occurred in 53 patients (10%). On multivariate Cox analysis, higher STS score (hazard ratio [HR] 1.50, 95% CI 1.20 to 1.88), higher baseline RVSP (HR 1.17, 95% CI 1.02 to 1.35), and higher ln BNP (HR 2.51, 95% CI 1.86 to 3.39) predicted death, whereas mitral surgery (HR 0.17, 95% CI 0.09 to 0.30) was associated with improved survival (all p <0.01). Eighty-nine percent of deaths occurred in patients with lnBNP >4.1. Addition of lnBNP to a model of STS score, baseline RVSP, and mitral surgery provided incremental prognostic utility (chi-square for mortality increased from 137 to 162, p <0.001). In conclusion, in asymptomatic patients with ≥ 3 + primary MR and preserved LVEF, the addition of BNP improved risk stratification and higher BNP independently predicted reduced survival.

Left Atrial Size and Function in a Canine Model of Chronic Atrial Fibrillation and Heart Failure

BACKGROUND

Our aim was to assess how atrial fibrillation (AF) induction, chronicity, and RR interval irregularity affect left atrial (LA) function and size in the setting of underlying heart failure (HF), and to determine whether AF effects can be mitigated by vagal nerve stimulation (VNS).

METHODS

HF was induced by 4-weeks of rapid ventricular pacing in 24 dogs. Subsequently, AF was induced and maintained by atrial pacing at 600 bpm. Dogs were randomized into control (n = 9) and VNS (n = 15) groups. In the VNS group, atrioventricular node fat pad stimulation (310 μs, 20 Hz, 3-7 mA) was delivered continuously for 6 months. LA volume and LA strain data were calculated from bi-weekly echocardiograms.

RESULTS

RR intervals decreased with HF in both groups (p = 0.001), and decreased further during AF in control group (p = 0.014), with a non-significant increase in the VNS group during AF. LA size increased with HF (p<0.0001), with no additional increase during AF. LA strain decreased with HF (p = 0.025) and further decreased after induction of AF (p = 0.0001). LA strain decreased less (p = 0.001) in the VNS than in the control group. Beat-by-beat analysis showed a curvilinear increase of LA strain with longer preceding RR interval, (r = 0.45, p <0.0001) with LA strain 1.1% higher (p = 0.02) in the VNS-treated animals, independent of preceding RR interval duration. The curvilinear relationship between ratio of preceding and pre-preceding RR intervals, and subsequent LA strain was weaker, (r = 0.28, p = 0.001). However, VNS-treated animals again had higher LA strain (by 2.2%, p = 0.002) independently of the ratio of preceding and pre-preceding RR intervals.

CONCLUSIONS

In the underlying presence of pacing-induced HF, AF decreased LA strain, with little impact on LA size. LA strain depends on the preceding RR interval duration.

Synergistic Utility of Brain Natriuretic Peptide and Left Ventricular Strain in Patients With Significant Aortic Stenosis

BACKGROUND

In aortic stenosis (AS), symptoms and left ventricular (LV) dysfunction represent a later disease state, and objective parameters that identify incipient LV dysfunction are needed. We sought to determine prognostic utility of brain natriuretic peptide (BNP) and left ventricular global longitudinal strain (LV-GLS) in patients with aortic valve area <1.3 cm(2).

METHODS AND RESULTS

Five-hundred and thirty-one patients between January 2007 and December 2008 with aortic valve area <1.3 cm(2) (86% with aortic valve area ≤1.1 cm(2)) and left ventricular ejection fraction ≥50% who had BNP drawn ≤90 days from initial echo were included. Society of Thoracic Surgeons (STS) score and mortality were recorded. Mean STS score, glomerular filtration rate, and median BNP were 11±5, 73±35 mL/min per 1.73 m , and 141 (60-313) pg/mL, respectively; 78% were in New York Heart Association class ≥II. Mean LV-stroke volume index (LV-SVI) and LV-GLS were 39±10 mL/m(2) and -13.9±3%. At 4.7±2 years, 405 patients (76%) underwent aortic valve replacement; 161 died (30%). On multivariable survival analysis, age (hazard ratio [HR] 1.46), New York Heart Association class (HR 1.27), coronary artery disease (HR 1.72), decreasing glomerular filtration rate (HR 1.15), increasing BNP (HR 1.16), worsening LV-GLS (HR 1.13) and aortic valve replacement (time dependent) (HR 0.34) predicted survival (all P<0.01). For mortality, the c-statistic incrementally increased as follows (all P<0.01): STS score (0.60 [0.58-0.64]), STS score+BNP (0.67 [0.62-0.70]), and STS score+BNP+LV-GLS (0.74 [0.68-0.78]).

CONCLUSIONS

In normal LVEF patients with significant aortic stenosis, BNP and LV-GLS provide incremental (additive not duplicative) prognostic information over established predictors, suggesting that both play a synergistic role in defining outcomes.

Impact of additive mitral valve surgery to coronary artery bypass grafting on mortality in patients with coronary artery disease and ischaemic mitral regurgitation: a systematic review and meta-analysis of randomized trials and observational studies

Aims

Treatment of ischaemic mitral regurgitation (IMR) remains controversial. While IMR is associated with worse outcomes, randomized controlled trials (RCTs) and observational studies provided conflicting evidence regarding the benefit of mitral valve replacement (MVR) or repair (MVr) in addition to coronary artery bypass grafting (CABG). We conducted a meta-analysis incorporating data from published RCTs and observational studies comparing CABG vs. CABG + MVR/MVr.

Methods and results

We searched PubMed, MEDLINE, Embase, Ovid, and Cochrane for RCTs and observational studies comparing CABG (Group 1) vs. CABG + MVR/MVr (Group 2). Outcome was 30-day and 1-year mortality after surgical intervention. Mantel-Haenszel odds ratio (OR) was calculated using random-effects meta-analysis for the outcome. Heterogeneity was assessed by I2 statistics. Four RCTs and 11 observational studies met the inclusion criteria (5781 patients, 507 in RCTs, 5274 in observational studies). Group 1 vs. 2 weighted mean left ventricular ejection fraction in RCTs and combined RCTs/observational studies was 41.5 ± 12.3 vs. 40.3 ± 10.4% ( P -value = 0.24) and 45.5 ± 7.2 vs. 38 ± 10% ( P -value < 0.001), respectively. In RCTs, there was no difference in 30-day [OR: 0.95, 95% confidence interval (95% CI): 0.30-3.08, P = 0.94] or 1-year (OR: 0.90, 95% CI: 0.43-1.87, P = 0.78) mortality, respectively. For combined RCTs/observational studies, there was no difference in mortality at 30 days (OR: 0.67, 95% CI: 0.43-1.04, P = 0.08) or at 1 year (OR: 0.90, 95% CI: 0.7-1.15, P = 0.39).

Conclusion

In a meta-analysis of RCTs and observational studies of IMR patients, the addition of MVR/MVr to CABG did not improve survival.

Comprehensive Echocardiographic Detection of Treatment-Related Cardiac Dysfunction in Adult Survivors of Childhood Cancer: Results From the St. Jude Lifetime Cohort Study

BACKGROUND

Treatment-related cardiac death is the primary, noncancer cause of mortality in adult survivors of childhood malignancies. Early detection of cardiac dysfunction may identify a high-risk subset of survivors for early intervention.

OBJECTIVES

This study sought to determine the prevalence of cardiac dysfunction in adult survivors of childhood malignancies.

METHODS

Echocardiographic assessment included 3-dimensional (3D) left ventricular ejection fraction (LVEF), global longitudinal and circumferential myocardial strain, and diastolic function, graded per American Society of Echocardiography guidelines in 1,820 adult (median age 31 years; range: 18 to 65 years) survivors of childhood cancer (median time from diagnosis 23 years; range: 10 to 48 years) exposed to anthracycline chemotherapy (n = 1,050), chest-directed radiotherapy (n = 306), or both (n = 464).

RESULTS

Only 5.8% of survivors had abnormal 3D LVEFs (<50%). However, 32.1% of survivors with normal 3D LVEFs had evidence of cardiac dysfunction by global longitudinal strain (28%), American Society of Echocardiography-graded diastolic assessment (8.7%), or both. Abnormal global longitudinal strain was associated with chest-directed radiotherapy at 1 to 19.9 Gy (rate ratio [RR]: 1.38; 95% confidence interval [CI]: 1.14 to 1.66), 20 to 29.9 Gy (RR: 1.65; 95% CI: 1.31 to 2.08), and >30 Gy (RR: 2.39; 95% CI: 1.79 to 3.18) and anthracycline dose > 300 mg/m(2) (RR: 1.72; 95% CI: 1.31 to 2.26). Survivors with metabolic syndrome were twice as likely to have abnormal global longitudinal strain (RR: 1.94; 95% CI: 1.66 to 2.28) and abnormal diastolic function (RR: 1.68; 95% CI: 1.39 to 2.03) but not abnormal 3D LVEFs (RR: 1.07; 95% CI: 0.74 to 1.53).

CONCLUSIONS

Abnormal global longitudinal strain and diastolic function are more prevalent than reduced 3D LVEF and are associated with treatment exposure. They may identify a subset of survivors at higher risk for poor clinical cardiac outcomes who may benefit from early medical intervention.

The Alternative Splicing of Cytoplasmic Polyadenylation Element Binding Protein 2 Drives Anoikis Resistance and the Metastasis of Triple Negative Breast Cancer

Triple negative breast cancer (TNBC) represents an anomalous subset of breast cancer with a greatly reduced (30%) 5-year survival rate. The enhanced mortality and morbidity of TNBC arises from the high metastatic rate, which requires the acquisition of AnR, a process whereby anchorage-dependent cells become resistant to cell death induced by detachment. In this study TNBC cell lines were selected for AnR, and these cell lines demonstrated dramatic enhancement in the formation of lung metastases as compared with parental cells. Genetic analysis of the AnR subclones versus parental cells via next generation sequencing and analysis of global alternative RNA splicing identified that the mRNA splicing of cytoplasmic polyadenylation element binding 2 (CPEB2), a translational regulator, was altered in AnR TNBC cells. Specifically, increased inclusion of exon 4 into the mature mRNA to produce the CPEB2B isoform was observed in AnR cell lines. Molecular manipulations of CPEB2 splice variants demonstrated a key role for this RNA splicing event in the resistance of cells to anoikis. Specifically, down-regulation of the CPEB2B isoform using siRNA re-sensitized the AnR cell lines to detachment-induced cell death. The ectopic expression of CPEB2B in parental TNBC cell lines induced AnR and dramatically increased metastatic potential. Importantly, alterations in the alternative splicing of CPEB2 were also observed in human TNBC and additional subtypes of human breast cancer tumors linked to a high metastatic rate. Our findings demonstrate that the regulation of CPEB2 mRNA splicing is a key mechanism in AnR and a driving force in TNBC metastasis.