Transcatheter Aortic-Valve Replacement with a Balloon-Expandable Valve in Low-Risk Patients

BACKGROUND

Among patients with aortic stenosis who are at intermediate or high risk for death with surgery, major outcomes are similar with transcatheter aortic-valve replacement (TAVR) and surgical aortic-valve replacement. There is insufficient evidence regarding the comparison of the two procedures in patients who are at low risk.

METHODS

We randomly assigned patients with severe aortic stenosis and low surgical risk to undergo either TAVR with transfemoral placement of a balloon-expandable valve or surgery. The primary end point was a composite of death, stroke, or rehospitalization at 1 year. Both noninferiority testing (with a prespecified margin of 6 percentage points) and superiority testing were performed in the as-treated population.

RESULTS

At 71 centers, 1000 patients underwent randomization. The mean age of the patients was 73 years, and the mean Society of Thoracic Surgeons risk score was 1.9% (with scores ranging from 0 to 100% and higher scores indicating a greater risk of death within 30 days after the procedure). The Kaplan-Meier estimate of the rate of the primary composite end point at 1 year was significantly lower in the TAVR group than in the surgery group (8.5% vs. 15.1%; absolute difference, -6.6 percentage points; 95% confidence interval [CI], -10.8 to -2.5; P<0.001 for noninferiority; hazard ratio, 0.54; 95% CI, 0.37 to 0.79; P = 0.001 for superiority). At 30 days, TAVR resulted in a lower rate of stroke than surgery (P = 0.02) and in lower rates of death or stroke (P = 0.01) and new-onset atrial fibrillation (P<0.001). TAVR also resulted in a shorter index hospitalization than surgery (P<0.001) and in a lower risk of a poor treatment outcome (death or a low Kansas City Cardiomyopathy Questionnaire score) at 30 days (P<0.001). There were no significant between-group differences in major vascular complications, new permanent pacemaker insertions, or moderate or severe paravalvular regurgitation.

CONCLUSIONS

Among patients with severe aortic stenosis who were at low surgical risk, the rate of the composite of death, stroke, or rehospitalization at 1 year was significantly lower with TAVR than with surgery. (Funded by Edwards Lifesciences; PARTNER 3 ClinicalTrials.gov number, NCT02675114.).

Transcatheter Aortic-Valve Replacement with a Self-Expanding Valve in Low-Risk Patients

BACKGROUND

Transcatheter aortic-valve replacement (TAVR) is an alternative to surgery in patients with severe aortic stenosis who are at increased risk for death from surgery; less is known about TAVR in low-risk patients.

METHODS

We performed a randomized noninferiority trial in which TAVR with a self-expanding supraannular bioprosthesis was compared with surgical aortic-valve replacement in patients who had severe aortic stenosis and were at low surgical risk. When 850 patients had reached 12-month follow-up, we analyzed data regarding the primary end point, a composite of death or disabling stroke at 24 months, using Bayesian methods.

RESULTS

Of the 1468 patients who underwent randomization, an attempted TAVR or surgical procedure was performed in 1403. The patients' mean age was 74 years. The 24-month estimated incidence of the primary end point was 5.3% in the TAVR group and 6.7% in the surgery group (difference, -1.4 percentage points; 95% Bayesian credible interval for difference, -4.9 to 2.1; posterior probability of noninferiority >0.999). At 30 days, patients who had undergone TAVR, as compared with surgery, had a lower incidence of disabling stroke (0.5% vs. 1.7%), bleeding complications (2.4% vs. 7.5%), acute kidney injury (0.9% vs. 2.8%), and atrial fibrillation (7.7% vs. 35.4%) and a higher incidence of moderate or severe aortic regurgitation (3.5% vs. 0.5%) and pacemaker implantation (17.4% vs. 6.1%). At 12 months, patients in the TAVR group had lower aortic-valve gradients than those in the surgery group (8.6 mm Hg vs. 11.2 mm Hg) and larger effective orifice areas (2.3 cm² vs. 2.0 cm²).

CONCLUSIONS

In patients with severe aortic stenosis who were at low surgical risk, TAVR with a self-expanding supraannular bioprosthesis was noninferior to surgery with respect to the composite end point of death or disabling stroke at 24 months. (Funded by Medtronic; ClinicalTrials.gov number, NCT02701283.).

Percutaneous transcatheter implantation of an aortic valve prosthesis for calcific aortic stenosis: first human case description

BACKGROUND

The design of a percutaneous implantable prosthetic heart valve has become an important area for investigation. A percutaneously implanted heart valve (PHV) composed of 3 bovine pericardial leaflets mounted within a balloon-expandable stent was developed. After ex vivo testing and animal implantation studies, the first human implantation was performed in a 57-year-old man with calcific aortic stenosis, cardiogenic shock, subacute leg ischemia, and other associated noncardiac diseases. Valve replacement had been declined for this patient, and balloon valvuloplasty had been performed with nonsustained results.

METHODS AND RESULTS

With the use of an antegrade transseptal approach, the PHV was successfully implanted within the diseased native aortic valve, with accurate and stable PHV positioning, no impairment of the coronary artery blood flow or of the mitral valve function, and a mild paravalvular aortic regurgitation. Immediately and at 48 hours after implantation, valve function was excellent, resulting in marked hemodynamic improvement. Over a follow-up period of 4 months, the valvular function remained satisfactory as assessed by sequential transesophageal echocardiography, and there was no recurrence of heart failure. However, severe noncardiac complications occurred, including a progressive worsening of the leg ischemia, leading to leg amputation with lack of healing, infection, and death 17 weeks after PHV implantation.

CONCLUSIONS

Nonsurgical implantation of a prosthetic heart valve can be successfully achieved with immediate and midterm hemodynamic and clinical improvement. After further device modifications, additional durability tests, and confirmatory clinical implantations, PHV might become an important therapeutic alternative for the treatment of selected patients with nonsurgical aortic stenosis.

Two-year outcomes after transcatheter or surgical aortic-valve replacement

BACKGROUND

The Placement of Aortic Transcatheter Valves (PARTNER) trial showed that among high-risk patients with aortic stenosis, the 1-year survival rates are similar with transcatheter aortic-valve replacement (TAVR) and surgical replacement. However, longer-term follow-up is necessary to determine whether TAVR has prolonged benefits.

METHODS

At 25 centers, we randomly assigned 699 high-risk patients with severe aortic stenosis to undergo either surgical aortic-valve replacement or TAVR. All patients were followed for at least 2 years, with assessment of clinical outcomes and echocardiographic evaluation.

RESULTS

The rates of death from any cause were similar in the TAVR and surgery groups (hazard ratio with TAVR, 0.90; 95% confidence interval [CI], 0.71 to 1.15; P=0.41) and at 2 years (Kaplan-Meier analysis) were 33.9% in the TAVR group and 35.0% in the surgery group (P=0.78). The frequency of all strokes during follow-up did not differ significantly between the two groups (hazard ratio, 1.22; 95% CI, 0.67 to 2.23; P=0.52). At 30 days, strokes were more frequent with TAVR than with surgical replacement (4.6% vs. 2.4%, P=0.12); subsequently, there were 8 additional strokes in the TAVR group and 12 in the surgery group. Improvement in valve areas was similar with TAVR and surgical replacement and was maintained for 2 years. Paravalvular regurgitation was more frequent after TAVR (P<0.001), and even mild paravalvular regurgitation was associated with increased late mortality (P<0.001).

CONCLUSIONS

A 2-year follow-up of patients in the PARTNER trial supports TAVR as an alternative to surgery in high-risk patients. The two treatments were similar with respect to mortality, reduction in symptoms, and improved valve hemodynamics, but paravalvular regurgitation was more frequent after TAVR and was associated with increased late mortality. (Funded by Edwards Lifesciences; ClinicalTrials.gov number, NCT00530894.).

Clinical factors associated with calcific aortic valve disease. Cardiovascular Health Study

OBJECTIVES

The aim of this study was to determine the prevalence of aortic sclerosis and stenosis in the elderly and to identify clinical factors associated with degenerative aortic valve disease.

BACKGROUND

Several lines of evidence suggest that degenerative aortic valve disease is not an inevitable consequence of aging and may be associated with specific clinical factors.

METHODS

In 5,201 subjects > or = 65 years of age enrolled in the Cardiovascular Health Study, the relation between aortic sclerosis or stenosis identified on echocardiography and clinical risk factors for atherosclerosis was evaluated by using stepwise logistic regression analysis.

RESULTS

Aortic valve sclerosis was present in 26% and aortic valve stenosis in 2% of the entire study cohort; in subjects > or = 75 years of age, sclerosis was present in 37% and stenosis in 2.6%. Independent clinical factors associated with degenerative aortic valve disease included age (twofold increased risk for each 10-year increase in age), male gender (twofold excess risk), present smoking (35% increase in risk) and a history of hypertension (20% increase in risk). Other significant factors included height and high lipoprotein(a) and low density lipoprotein cholesterol levels.

CONCLUSIONS

Clinical factors associated with aortic sclerosis and stenosis can be identified and are similar to risk factors for atherosclerosis.

Transcatheter aortic-valve replacement for inoperable severe aortic stenosis

BACKGROUND

Transcatheter aortic-valve replacement (TAVR) is the recommended therapy for patients with severe aortic stenosis who are not suitable candidates for surgery. The outcomes beyond 1 year in such patients are not known.

METHODS

We randomly assigned patients to transfemoral TAVR or to standard therapy (which often included balloon aortic valvuloplasty). Data on 2-year outcomes were analyzed.

RESULTS

A total of 358 patients underwent randomization at 21 centers. The rates of death at 2 years were 43.3% in the TAVR group and 68.0% in the standard-therapy group (P<0.001), and the corresponding rates of cardiac death were 31.0% and 62.4% (P<0.001). The survival advantage associated with TAVR that was seen at 1 year remained significant among patients who survived beyond the first year (hazard ratio, 0.58; 95% confidence interval [CI], 0.36 to 0.92; P=0.02 with the use of the log-rank test). The rate of stroke was higher after TAVR than with standard therapy (13.8% vs. 5.5%, P=0.01), owing, in the first 30 days, to the occurrence of more ischemic events in the TAVR group (6.7% vs. 1.7%, P=0.02) and, beyond 30 days, to the occurrence of more hemorrhagic strokes in the TAVR group (2.2% vs. 0.6%, P=0.16). At 2 years, the rate of rehospitalization was 35.0% in the TAVR group and 72.5% in the standard-therapy group (P<0.001). TAVR, as compared with standard therapy, was also associated with improved functional status (P<0.001). The data suggest that the mortality benefit after TAVR may be limited to patients who do not have extensive coexisting conditions. Echocardiographic analysis showed a sustained increase in aortic-valve area and a decrease in aortic-valve gradient, with no worsening of paravalvular aortic regurgitation.

CONCLUSIONS

Among appropriately selected patients with severe aortic stenosis who were not suitable candidates for surgery, TAVR reduced the rates of death and hospitalization, with a decrease in symptoms and an improvement in valve hemodynamics that were sustained at 2 years of follow-up. The presence of extensive coexisting conditions may attenuate the survival benefit of TAVR. (Funded by Edwards Lifesciences; ClinicalTrials.gov number, NCT00530894.).

Registry of transcatheter aortic-valve implantation in high-risk patients

BACKGROUND

Transcatheter aortic-valve implantation (TAVI) is an emerging intervention for the treatment of high-risk patients with severe aortic stenosis and coexisting illnesses. We report the results of a prospective multicenter study of the French national transcatheter aortic-valve implantation registry, FRANCE 2.

METHODS

All TAVIs performed in France, as listed in the FRANCE 2 registry, were prospectively included in the study. The primary end point was death from any cause.

RESULTS

A total of 3195 patients were enrolled between January 2010 and October 2011 at 34 centers. The mean (±SD) age was 82.7±7.2 years; 49% of the patients were women. All patients were highly symptomatic and were at high surgical risk for aortic-valve replacement. Edwards SAPIEN and Medtronic CoreValve devices were implanted in 66.9% and 33.1% of patients, respectively. Approaches were either transarterial (transfemoral, 74.6%; subclavian, 5.8%; and other, 1.8%) or transapical (17.8%). The procedural success rate was 96.9%. Rates of death at 30 days and 1 year were 9.7% and 24.0%, respectively. At 1 year, the incidence of stroke was 4.1%, and the incidence of periprosthetic aortic regurgitation was 64.5%. In a multivariate model, a higher logistic risk score on the European System for Cardiac Operative Risk Evaluation (EuroSCORE), New York Heart Association functional class III or IV symptoms, the use of a transapical TAVI approach, and a higher amount of periprosthetic regurgitation were significantly associated with reduced survival.

CONCLUSIONS

This prospective registry study reflected real-life TAVI experience in high-risk elderly patients with aortic stenosis, in whom TAVI appeared to be a reasonable option. (Funded by Edwards Lifesciences and Medtronic.).

Progression from compensated hypertrophy to failure in the pressure-overloaded human heart: structural deterioration and compensatory mechanisms

BACKGROUND

The progression of compensated hypertrophy to heart failure (HF) is still debated. We investigated patients with isolated valvular aortic stenosis and differing degrees of left ventricular (LV) systolic dysfunction to test the hypothesis that structural remodeling, as well as cell death, contributes to the transition to HF.

METHODS AND RESULTS

Structural alterations were studied in LV myectomies from 3 groups of patients (group 1: ejection fraction [EF] >50%, n=12; group 2: EF 30% to 50%, n=12; group 3: EF <30%, n=10) undergoing aortic valve replacement. Control patients were patients with mitral valve stenosis but normal LV (n=6). Myocyte hypertrophy was accompanied by increased nuclear DNA and Sc-35 (splicing factor) content. ACE and TGF-beta1 were upregulated correlating with fibrosis, which increased 2.3-, 2.2-, and 3.2-fold over control in the 3 groups. Myocyte degeneration increased 10, 22, and 32 times over control. A significant correlation exists between EF and myocyte degeneration or fibrosis. Ubiquitin-related autophagic cell death was 0.5 per thousand in control and group 1, 1.05 in group 2, and 6.05 per thousand in group 3. Death by oncosis was 0 per thousand in control, 3 per thousand in group 1, and increased to 5 per thousand (groups 2 and 3). Apoptosis was not detectable in control and group 3, but it was present at 0.02 per thousand in group 1 and 0.01 per thousand in group 2. Cardiomyocyte mitosis was never observed.

CONCLUSIONS

These structure-function correlations confirm the hypothesis that transition to HF occurs by fibrosis and myocyte degeneration partially compensated by hypertrophy involving DNA synthesis and transcription. Cell loss, mainly by autophagy and oncosis, contributes significantly to the progression of LV systolic dysfunction.

Galectin-3 marks activated macrophages in failure-prone hypertrophied hearts and contributes to cardiac dysfunction

BACKGROUND

Inflammatory mechanisms have been proposed to be important in heart failure (HF), and cytokines have been implicated to add to the progression of HF. However, it is unclear whether such mechanisms are already activated when hypertrophied hearts still appear well-compensated and whether such early mechanisms contribute to the development of HF.

METHODS AND RESULTS

In a comprehensive microarray study, galectin-3 emerged as the most robustly overexpressed gene in failing versus functionally compensated hearts from homozygous transgenic TGRmRen2-27 (Ren-2) rats. Myocardial biopsies obtained at an early stage of hypertrophy before apparent HF showed that expression of galectin-3 was increased specifically in the rats that later rapidly developed HF. Galectin-3 colocalized with activated myocardial macrophages. We found galectin-3-binding sites in rat cardiac fibroblasts and the extracellular matrix. Recombinant galectin-3 induced cardiac fibroblast proliferation, collagen production, and cyclin D1 expression. A 4-week continuous infusion of low-dose galectin-3 into the pericardial sac of healthy Sprague-Dawley rats led to left ventricular dysfunction, with a 3-fold differential increase of collagen I over collagen III. Myocardial galectin-3 expression was increased in aortic stenosis patients with depressed ejection fraction.

CONCLUSIONS

This study shows that an early increase in galectin-3 expression identifies failure-prone hypertrophied hearts. Galectin-3, a macrophage-derived mediator, induces cardiac fibroblast proliferation, collagen deposition, and ventricular dysfunction. This implies that HF therapy aimed at inflammatory responses may need to be targeted at the early stages of HF and probably needs to antagonize multiple inflammatory mediators, including galectin-3.

MicroRNAs play an essential role in the development of cardiac hypertrophy

MicroRNAs are naturally existing, small, noncoding RNA molecules that downregulate posttranscriptional gene expression. Their expression pattern and function in the heart remain unknown. Here we report an array of microRNAs that are differentially and temporally regulated during cardiac hypertrophy. Significantly, the muscle-specific microRNA-1 (miR-1) was singularly downregulated as early as day 1 (0.56+/-0.036), persisting through day 7 (0.29+/-0.14), after aortic constriction-induced hypertrophy in a mouse model. Overexpression experiments showed that miR-1 inhibited its in silico-predicted, growth-related targets, including Ras GTPase-activating protein (RasGAP), cyclin-dependent kinase 9 (Cdk9), fibronectin, and Ras homolog enriched in brain (Rheb), in addition to protein synthesis and cell size. Thus, we propose that microRNAs play an essential regulatory role in the development of cardiac hypertrophy, wherein downregulation of miR-1 is necessary for the relief of growth-related target genes from its repressive influence and induction of hypertrophy.

Treatment of Calcific Aortic Stenosis With the Percutaneous Heart Valve

OBJECTIVES

The aim of this work was to study the feasibility, safety, efficacy, and durability of percutaneous heart valve (PHV) implantation in the aortic position.

BACKGROUND

We developed a PHV (equine pericardium valve in a balloon-expandable, stainless-steel stent) to treat patients with inoperable aortic stenosis (AS).

METHODS

Thirty-six patients (aortic valve area < or =0.7 cm2, New York Heart Association [NYHA] functional class IV, and severe comorbidities), formally declined for surgery, were recruited on a compassionate basis. The PHV was implanted by retrograde or antegrade trans-septal approach. Clinical and echocardiographic outcomes were assessed serially.

RESULTS

Twenty-seven patients were implanted successfully (23 antegrade, 4 retrograde) in the subcoronary position with improvement in valve area (0.60 +/- 0.11 cm2 to 1.70 +/- 0.10 cm2, p < 0.0001) and transvalvular gradient (37 +/- 13 mm Hg to 9 +/- 2 mm Hg, p < 0.0001). Paravalvular aortic regurgitation was grade 0 to 1 (n = 10), grade 2 (n = 12), and grade 3 (n = 5). One week post-procedure, improvement in left ventricular function (45 +/- 18% to 53 +/- 14%, p = 0.02) was most pronounced in patients with ejection fraction <50% (35 +/- 10% to 50 +/- 16%, p < 0.0001). Thirty-day major adverse events after successful implantation were 26% (pericardial tamponade, stroke, arrhythmia, urosepsis, and one death unexplained at autopsy). Eleven patients are currently alive with follow-up of 9 months (n = 2), 10 months (n = 3), 11 months (n = 1), 12 months (n = 2), 23 months (n = 1), and 26 months (n = 2). All patients experienced amelioration of symptoms (>90% NYHA functional class I to II). Percutaneous heart valve function remained unchanged during follow-up, and no deaths were device-related.

CONCLUSIONS

Percutaneous heart valve implantation is feasible in inoperable patients with end-stage AS leading to hemodynamic and clinical improvement. Continued advances and improved patient selection should decrease adverse events in the near future.

Acquired von Willebrand syndrome in aortic stenosis

BACKGROUND

Aortic-valve stenosis can be complicated by bleeding that is associated with acquired type 2A von Willebrand syndrome. However, the prevalence and cause of the hemostatic abnormality in aortic stenosis are unknown.

METHODS

We enrolled 50 consecutive patients with aortic stenosis, who completed a standardized screening questionnaire to detect a history of bleeding. Forty-two patients with severe aortic stenosis underwent valve replacement. Platelet function under conditions of high shear stress, von Willebrand factor collagen-binding activity and antigen levels, and the multimeric structure of von Willebrand factor were assessed at base line and one day, seven days, and six months postoperatively.

RESULTS

Skin or mucosal bleeding occurred in 21 percent of the patients with severe aortic stenosis. Platelet-function abnormalities under conditions of high shear stress, decreased von Willebrand factor collagen-binding activity and the loss of the largest multimers, or a combination of these was present in 67 to 92 percent of patients with severe aortic stenosis and correlated significantly with the severity of valve stenosis. Primary hemostatic abnormalities were completely corrected on the first day after surgery but tended to recur at six months, especially when there was a mismatch between patient and prosthesis (with an effective orifice area of less than 0.8 cm2 per square meter of body-surface area).

CONCLUSIONS

Type 2A von Willebrand syndrome is common in patients with severe aortic stenosis. Von Willebrand factor abnormalities are directly related to the severity of aortic stenosis and are improved by valve replacement in the absence of mismatch between patient and prosthesis.

Unveiling transthyretin cardiac amyloidosis and its predictors among elderly patients with severe aortic stenosis undergoing transcatheter aortic valve replacement

AIMS

Transthyretin cardiac amyloidosis (ATTR-CA) has been reported in patients with aortic stenosis (AS) but its prevalence and phenotype are not known. We examine elderly patients with severe symptomatic AS undergoing transcatheter aortic valve replacement (TAVR) and determine the prevalence and phenotype of ATTR-CA non-invasively.

METHODS AND RESULTS

We performed technetium-99m pyrophosphate (99mTc-PYP) cardiac scintigraphy prospectively on patients who underwent TAVR, to screen for ATTR-CA. Transthoracic echocardiography and speckle-strain imaging were performed. We assessed the association of several parameters with ATTR-CA using multivariable logistic regression and constructed receiver operating curves to evaluate the best predictors of ATTR-CA. Among 151 patients (mean age 84 ± 6 years, 68% men), 16% (n = 24) screened positive for ATTR-CA with 99mTc-PYP scintigraphy. Compared with patients without ATTR-CA, ATTR-CA patients had a thicker interventricular septum (1.3 vs. 1.1 cm, P = 0.007), higher left ventricular (LV) mass index (130 vs. 98 g/m2, P = 0.002), and lower stroke volume index (30 vs. 36 mL/m2, P = 0.009). ATTR-CA patients had advanced diastolic dysfunction with higher E/A ratio (2.3 vs. 0.9, P = 0.001) and lower deceleration time (176 vs. 257 ms, P < 0.0001); impairment in systolic function with lower ejection fraction (48% vs. 56%, P = 0.011), myocardial contraction fraction (26 vs. 41, P < 0.0001), and average of lateral and septal mitral annular tissue Doppler S' (4.0 vs. 6.6 cm/s, P < 0.0001). While ATTR-CA patients had more impaired global longitudinal strain (-12 vs. -16%, P = 0.007), relative apical longitudinal strain was the same regardless of ATTR-CA diagnosis (0.98 vs. 0.98, P = 0.991). Average S' best predicted ATTR-CA in multivariable logistic regression (odds ratio 16.67 per 1 cm/s decrease with AUC 0.96, 95% confidence interval 0.90-0.99, P = 0.002) with a value ≤6 conferring 100% sensitivity for predicting a positive 99mTc-PYP amyloid scan.

CONCLUSIONS

Transthyretin cardiac amyloidosis is prevalent in 16% of patients with severe calcific AS undergoing TAVR and is associated with a severe AS phenotype of low-flow low-gradient with mildly reduced ejection fraction. Average tissue Doppler mitral annular S' of < 6 cm/s may be a sensitive measure that should prompt a confirmatory 99mTc-PYP scan and subsequent testing for ATTR-CA. Prospective assessment of outcomes after TAVR is needed in patients with and without ATTR-CA.

Five-Year Outcomes of Transcatheter or Surgical Aortic-Valve Replacement

BACKGROUND

There are scant data on long-term clinical outcomes and bioprosthetic-valve function after transcatheter aortic-valve replacement (TAVR) as compared with surgical aortic-valve replacement in patients with severe aortic stenosis and intermediate surgical risk.

METHODS

We enrolled 2032 intermediate-risk patients with severe, symptomatic aortic stenosis at 57 centers. Patients were stratified according to intended transfemoral or transthoracic access (76.3% and 23.7%, respectively) and were randomly assigned to undergo either TAVR or surgical replacement. Clinical, echocardiographic, and health-status outcomes were followed for 5 years. The primary end point was death from any cause or disabling stroke.

RESULTS

At 5 years, there was no significant difference in the incidence of death from any cause or disabling stroke between the TAVR group and the surgery group (47.9% and 43.4%, respectively; hazard ratio, 1.09; 95% confidence interval [CI], 0.95 to 1.25; P = 0.21). Results were similar for the transfemoral-access cohort (44.5% and 42.0%, respectively; hazard ratio, 1.02; 95% CI, 0.87 to 1.20), but the incidence of death or disabling stroke was higher after TAVR than after surgery in the transthoracic-access cohort (59.3% vs. 48.3%; hazard ratio, 1.32; 95% CI, 1.02 to 1.71). At 5 years, more patients in the TAVR group than in the surgery group had at least mild paravalvular aortic regurgitation (33.3% vs. 6.3%). Repeat hospitalizations were more frequent after TAVR than after surgery (33.3% vs. 25.2%), as were aortic-valve reinterventions (3.2% vs. 0.8%). Improvement in health status at 5 years was similar for TAVR and surgery.

CONCLUSIONS

Among patients with aortic stenosis who were at intermediate surgical risk, there was no significant difference in the incidence of death or disabling stroke at 5 years after TAVR as compared with surgical aortic-valve replacement. (Funded by Edwards Lifesciences; PARTNER 2 ClinicalTrials.gov number, NCT01314313.).

Prolonged endoplasmic reticulum stress in hypertrophic and failing heart after aortic constriction: possible contribution of endoplasmic reticulum stress to cardiac myocyte apoptosis

BACKGROUND

The endoplasmic reticulum (ER) is recognized as an organelle that participates in folding secretory and membrane proteins. The ER responds to stress by upregulating ER chaperones, but prolonged and/or excess ER stress leads to apoptosis. However, the potential role of ER stress in pathophysiological hearts remains unclear.

METHODS AND RESULTS

Mice were subjected to transverse aortic constriction (TAC) or sham operation. Echocardiographic analysis demonstrated that mice 1 and 4 weeks after TAC had cardiac hypertrophy and failure, respectively. Cardiac expression of ER chaperones was significantly increased 1 and 4 weeks after TAC, indicating that pressure overload by TAC induced prolonged ER stress. In addition, the number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells increased, and caspase-3 was cleaved in failing hearts. The antagonism of angiotensin II type 1 receptor prevented upregulation of ER chaperones and apoptosis in failing hearts. On the other hand, angiotensin II upregulated ER chaperones and induced apoptosis in cultured adult rat cardiac myocytes. We also investigated possible signaling pathways for ER-initiated apoptosis. The CHOP- (a transcription factor induced by ER stress), but not JNK- or caspase-12-, dependent pathway was activated in failing hearts by TAC. Pharmacological ER stress inducers upregulated ER chaperones and induced apoptosis in cultured cardiac myocytes. Finally, mRNA levels of ER chaperones were markedly increased in failing hearts of patients with elevated brain natriuretic peptide levels.

CONCLUSIONS

These findings suggest that pressure overload by TAC induces prolonged ER stress, which may contribute to cardiac myocyte apoptosis during progression from cardiac hypertrophy to failure.

Decreased coronary reserve: a mechanism for angina pectoris in patients with aortic stenosis and normal coronary arteries

The pathogenesis of angina pectoris in patients with aortic stenosis and normal coronary arteries remains uncertain. Using a specially designed Doppler probe, we measured the maximal velocity of coronary blood flow in the left-anterior descending coronary artery at the time of elective open-heart surgery in 14 patients with aortic stenosis and left ventricular hypertrophy (13 had angina) and in 8 controls without left ventricular hypertrophy. The ratio peak velocity of coronary blood flow, after a 20-second occlusion, to resting velocity was decreased by more than 50 per cent (P less than 0.05) in the patients with aortic stenosis. In 7 of the patients this ratio was decreased by more than 75 per cent. Studies of the velocity of coronary blood flow in vessels perfusing the right ventricle in these patients showed only mild abnormalities. These data demonstrate a selective and marked decrease in coronary reserve to the hypertrophied left ventricle in patients with severe aortic stenosis. The impairment in coronary reserve is probably an important contributor to the pathogenesis of angina pectoris in these patients.

The creatine kinase system in normal and diseased human myocardium

We measured creatine kinase activity, isozyme composition, and total creatine content in biopsy samples of left ventricular myocardium from 34 adults in four groups: subjects with normal left ventricles, patients with left ventricular hypertrophy due to aortic stenosis, patients with coronary artery disease without left ventricular hypertrophy, and patients with coronary artery disease and left ventricular hypertrophy due to aortic stenosis. As compared with specimens of normal left ventricles, those from all patients with left ventricular hypertrophy had lower creatine kinase activity, higher MB creatine kinase isozyme content and activity, and lower creatine content. Specimens from the patients without left ventricular hypertrophy had normal creatine kinase activity, increased MB creatine kinase isozyme content and activity, and decreased total creatine content. The normal ventricles showed almost no MB isozyme content or activity. These data suggest that changes in the creatine kinase system occur in both pressure-overload hypertrophy and coronary artery disease. Patients with myocardial infarction who have mild or no preexisting fixed coronary artery disease or pressure-overload hypertrophy would not be expected to have elevation of serum MB creatine kinase.

Apoptosis in pressure overload-induced heart hypertrophy in the rat

Pressure overload induces cardiac growth in the rat, which implies the hypertrophy of cardiac muscle cells and proliferation of nonmuscle cells. The cardiac cell loss observed in parallel has generally been attributed to necrosis. Using an in situ assay, we demonstrated a phase of apoptosis or programmed cell death during the first 7 d after pressure overload with a peak at day 4 while cardiac growth continued for over 30 d. The increase in apoptosis was confirmed by quantification of 180-1500-bp DNA oligonucleosomes with agarose gel electrophoresis and in situ labeling via 3'-terminal deoxynucleotidyl transferase assay. While some apoptosis was observed in the basal state in nonmuscle cells, pressure overload induced apoptosis mainly in cardiomyocytes. These data suggest that cardiac hypertrophy is initiated by a wave of apoptosis of cardiomyocytes. Thus, apoptosis may be involved in the pathogenesis of heart remodeling.

Natriuretic peptides predict symptom-free survival and postoperative outcome in severe aortic stenosis

BACKGROUND

The prognostic value of natriuretic peptides in aortic stenosis (AS) remains unknown.

METHODS AND RESULTS

B-type natriuretic peptide (BNP), N-terminal BNP (NtBNP), and N-terminal atrial natriuretic peptide (NtANP) were determined in 130 patients with severe AS (mean age, 70+/-12 years; mean gradient, 64+/-21 mm Hg; valve area, 0.64+/-0.15 cm2) who were followed up for 377+/-150 days. Natriuretic peptides increased with NYHA class and with decreasing ejection fraction (EF). Even asymptomatic patients frequently had elevated neurohormones. Asymptomatic patients who developed symptoms during follow-up had higher BNP and NtBNP levels at entry compared with those remaining asymptomatic (median for NtBNP, 131 pmol/L [interquartile range, 50 to 202 pmol/L] versus 31 pmol/L [range, 19 to 56 pmol/L]; P<0.001). Symptom-free survival at 3, 6, 9, and 12 months for patients with NtBNP <80 versus > or =80 pmol/L was 100%, 88+/-7%, 88+/-7%, and 69+/-13% compared with 92+/-8%, 58+/-14%, 35+/-15%, and 18+/-15%, respectively (P<0.001). Seventy-nine patients eventually underwent surgery because of symptoms. Considering preoperative neurohormone levels, age, NYHA class, aortic valve area, EF, and presence of coronary artery disease, we found that neurohormones, EF, and NYHA class predicted survival; neurohormones predicted postoperative symptomatic status; and neurohormones and preoperative EF predicted postoperative EF. However, by multivariate analysis, NtBNP was the only independent predictor of outcome.

CONCLUSIONS

In severe AS, natriuretic peptides provide important prognostic information beyond clinical and echocardiographic evaluation. NtBNP independently predicts symptom-free survival, and preoperative NtBNP independently predicts postoperative outcome with regard to survival, symptomatic status, and left ventricular function. Thus, neurohormones may gain particular importance for timing of surgery in asymptomatic severe AS.

Effect of hydroxymethylglutaryl coenzyme a reductase inhibitors on the progression of calcific aortic stenosis

BACKGROUND

Recent studies have supported the hypothesis that calcific aortic stenosis is the product of an active inflammatory process, with similarities to atherosclerosis. We sought to determine whether therapy with hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) might slow the progression of aortic stenosis.

METHODS AND RESULTS

A retrospective study of 174 patients (mean age 68+/-12 years) with mild to moderate calcific aortic stenosis was conducted. Patients required normal left ventricular function, </=2+ aortic regurgitation, and >/=2 echocardiograms performed at least 12 months apart. Fifty-seven patients (33%) received treatment with a statin; the remaining 117 (67%) did not. The statin group was older and had a higher prevalence of hypertension, diabetes mellitus, and coronary disease. During a mean follow-up of 21 months, patients treated with statin had a smaller increase in peak and mean gradient and a smaller decrease in aortic valve area. When annualized, the decrease in aortic valve area for the nonstatin group was 0.11+/-0.18 cm(2) compared with 0.06+/-0.16 cm(2) for those treated with a statin (P=0.03). In multivariate analysis, statin usage was a significant independent predictor of a smaller decrease in valve area (P=0.01) and a lesser increase in peak gradient (P=0.02).

CONCLUSIONS

Statin-treated patients, despite a higher risk profile for progression, had reduced aortic stenosis progression compared with those not treated with a statin. These data provide justification for a prospective randomized trial to substantiate whether statin therapy slows the progression of aortic stenosis.

The natural history of aortic valve stenosis

Despite different aetiologies, acquired aortic stenosis is a self-maintaining, slowly progressive process with good long-term prognosis. In 142 patients with mild stenosis, there was clinical progression within 10 years of the initial diagnosis in only 12% of patients. Twenty-five years after the diagnosis had been established, the severity of aortic stenosis was clinically unchanged in 38%, while 25% of patients had moderate stenosis and 35% had undergone valve replacement. Progression of moderate aortic stenosis was more rapid: the average time interval between the manifestation of moderate aortic stenosis and surgery was 13.4 years. Age at the onset of initial symptoms was related to aetiology: 39 +/- 18 years with rheumatic aortic stenoses, 48 +/- 6 years in patients with bicuspid valves who had no history of rheumatic fever, infective endocarditis or myocarditis, and 66 +/- 12 years in degenerative, calcific stenoses of tricuspid aortic valves. Patients with haemodynamically severe stenosis who had refused the recommended operation (n = 55) had an overall poor prognosis: mean survival averaged 23 +/- 5 months and the five-year probability of survival was 18 +/- 7%. All these patients died within 12 years of observation. Mean survival after the occurrence of angina pectoris was 45 +/- 13 months, after syncope 27 +/- 15 months, and after first occurrence of left heart failure 11 +/- 10 months.

Left ventricular hypertrophy: relationship of anatomic, echocardiographic and electrocardiographic findings

Anatomic, echocardiographic and ECG findings of left ventricular hypertrophy (LVH) were compared in 34 subjects. Echocardiographic LV mass correlated weel with postmortem LV weight (r = 0.96) and accurately diagnosed LVH (sensitivity 93%, specificity 95%). In contrast, Romhilt-Estes (RE) point score and Sokolow-Lyon (SL) voltage criteria for ECG LVH were insensitive (50% and 21%, respectively) but specific (both 95%). RE correlated weakly with LV weight (r = 0.64), but SL did not. Echocardiographic LV mass was then compared with RE and SL in an unselected clinical series of 100 subjects, in 28 subjects with severe aortic stenosis (AS) and in 14 with severe aortic regurgitation (AR). Results in the clinical series were comparable to those in the necropsy series. In the AS and AR groups, with a high prevalence of LVH, the low sensitivity of RE point score and Sl criteria led to poor overall results. Analysis of individual ECG variables showed that most voltage information is contained in leads aVL and V1. Correction of voltage for distance from the left ventricle did not substantially improve results. Individual nonvoltage criteria were each nearly as sensitive as RE point score. We could not devise new ECG criteria that improved diagnostic results. We conclude that the ECG is specific but insensitive in recognition of LVH. Moreover, when true LVH prevalence is less than 10%, more false-positive than true-positive diagnoses will be obtained. M-mode echocardiographic LV mass is superior to ECG criteria for clinical diagnosis of LVH.

Phosphodiesterase 9A controls nitric-oxide-independent cGMP and hypertrophic heart disease

Cyclic guanosine monophosphate (cGMP) is a second messenger molecule that transduces nitric-oxide- and natriuretic-peptide-coupled signalling, stimulating phosphorylation changes by protein kinase G. Enhancing cGMP synthesis or blocking its degradation by phosphodiesterase type 5A (PDE5A) protects against cardiovascular disease. However, cGMP stimulation alone is limited by counter-adaptions including PDE upregulation. Furthermore, although PDE5A regulates nitric-oxide-generated cGMP, nitric oxide signalling is often depressed by heart disease. PDEs controlling natriuretic-peptide-coupled cGMP remain uncertain. Here we show that cGMP-selective PDE9A (refs 7, 8) is expressed in the mammalian heart, including humans, and is upregulated by hypertrophy and cardiac failure. PDE9A regulates natriuretic-peptide- rather than nitric-oxide-stimulated cGMP in heart myocytes and muscle, and its genetic or selective pharmacological inhibition protects against pathological responses to neurohormones, and sustained pressure-overload stress. PDE9A inhibition reverses pre-established heart disease independent of nitric oxide synthase (NOS) activity, whereas PDE5A inhibition requires active NOS. Transcription factor activation and phosphoproteome analyses of myocytes with each PDE selectively inhibited reveals substantial differential targeting, with phosphorylation changes from PDE5A inhibition being more sensitive to NOS activation. Thus, unlike PDE5A, PDE9A can regulate cGMP signalling independent of the nitric oxide pathway, and its role in stress-induced heart disease suggests potential as a therapeutic target.