Echocardiographic measurement of left atrial volume: Does the method matter?

BACKGROUND

Four two-dimensional echocardiographic methods (cube, ellipsoid, Simpson's and area-length) can be used to assess left atrial volume (LAV).

AIMS

To compare absolute LAV measurements and evaluate agreement regarding the semiquantitative assessment of degree of left atrial (LA) enlargement, between methods.

METHODS

We prospectively measured LAV in 51 healthy volunteers using the four methods, and defined thresholds for moderate (mean+2 standard deviations [SDs]) and severe (mean+4 SDs) LA enlargement for each method. In 372 patients referred for echocardiography, we compared absolute LAV measurements and agreement between methods.

RESULTS

LAV was significantly different between methods in the healthy volunteer group (11 ± 4, 17 ± 3, 26 ± 6 and 28 ± 7 mL/m(2), respectively; P<0.0001), resulting in different thresholds for moderate and severe LA enlargement. LAV was also significantly different in the 372 patients (30 ± 20, 47 ± 27, 61 ± 34 and 65 ± 36 mL/m(2), respectively; P<0.0001). Agreement regarding degree of LA enlargement (none, moderate, severe), using the area-length method as reference, was modest with the cube method (kappa=0.41), correct with the ellipsoid method (kappa=0.60) and excellent with Simpson's method (kappa=0.83).

CONCLUSION

The choice of the method had a major effect on assessment of degree of LA enlargement. Our results suggest that the cube and ellipsoid methods, which significantly underestimated LAV and provided modest agreement, should be disregarded. In contrast, Simpson's method and the area-length method were slightly different, but showed close agreement, and should be preferred, using dedicated thresholds (50 and 56 mL/m(2) respectively).

Comparison of 2-Dimensional, 3-Dimensional, and Surgical Measurements of the Tricuspid Annulus Size: Clinical Implications

BACKGROUND

Associated tricuspid annuloplasty is recommended during left-heart valve surgery when the tricuspid annulus (TA) is dilated but methodology for the measurement of TA size and thresholds for TA enlargement are not clearly defined.

METHODS AND RESULTS

Measurement of the TA diameter (TAD) was prospectively performed using 2-dimensional transthoracic echocardiography (2D-TTE) in 282 patients in 4 different views (parasternal long axis, parasternal short axis, apical 4-chamber [A4C], and subcostal). TAD was also measured using 3D-transesophageal echocardiography in 183 patients (long axis), peroperatively in 120 patients who underwent a tricuspid valve surgery and using TTE (A4C) in 66 healthy volunteers. TAD was significantly different between the 4 2D-TTE views (3.85±0.58, 3.87±0.61, 4.02±0.69, and 3.92±0.65 cm, respectively; P<0.0001) but differences were small and the A4C was the most feasible (76%, 65%, 92%, and 73%, respectively; P<0.0001) and offered the highest reproducibility. TAD measured in A4C view was smaller than when measured by 3D-transesophageal echocardiography (3.90±0.63 versus 4.33±0.62 cm; P<0.0001) but correlation was excellent (r=0.84; P<0.0001) with a systematic 4-mm underestimation. In contrast, 2D-TTE measurements were significantly smaller and only modestly correlated to surgical measurements (4.11±0.61 versus 4.37±0.75 cm; P<0.0001; r=0.57; P<0.0001) which were poorly reproducible. In healthy volunteers, we suggested 42 mm or 23 mm/m(2) as pathological values for the TAD in A4C.

CONCLUSIONS

Measurements of the TAD using 2D-TTE in A4C were highly feasible and reproducible and despite being systematically smaller than 3D measurements, accurately reflected the degree of TA enlargement as assessed using 3D transesophageal echocardiography. We proposed the thresholds that may be used in future prospective studies to demonstrate whether a preventive strategy would improve the outcome.

The future of transcatheter mitral valve interventions: competitive or complementary role of repair vs. replacement?

Transcatheter mitral interventions has been developed to address an unmet clinical need and may be an alternative therapeutic option to surgery with the intent to provide symptomatic and prognostic benefit. Beyond MitraClip therapy, alternative repair technologies are being developed to expand the transcatheter intervention armamentarium. Recently, the feasibility of transcatheter mitral valve implantation in native non-calcified valves has been reported in very high-risk patients. Acknowledging the lack of scientific evidence to date, it is difficult to predict what the ultimate future role of transcatheter mitral valve interventions will be. The purpose of the present report is to review the current state-of-the-art of mitral valve intervention, and to identify the potential future scenarios, which might benefit most from the transcatheter repair and replacement devices under development.

Infective endocarditis after transcatheter aortic valve implantation: results from a large multicenter registry

BACKGROUND

We aimed to determine the incidence, predictors, clinical characteristics, management, and outcomes of infective endocarditis (IE) after transcatheter aortic valve implantation (TAVI).

METHODS AND RESULTS

This multicenter registry included 53 patients (mean age, 79±8 years; men, 57%) who suffered IE after TAVI of 7944 patients after a mean follow-up of 1.1±1.2 years (incidence, 0.67%, 0.50% within the first year after TAVI). Mean time from TAVI was 6 months (interquartile range, 1-14 months). Orotracheal intubation (hazard ratio, 3.87; 95% confidence interval, 1.55-9.64; P=0.004) and the self-expandable CoreValve system (hazard ratio, 3.12; 95% confidence interval, 1.37-7.14; P=0.007) were associated with IE (multivariate analysis including 3067 patients with individual data). The most frequent causal microorganisms were coagulase-negative staphylococci (24%), followed by Staphylococcus aureus (21%) and enterococci (21%). Vegetations were present in 77% of patients (transcatheter valve leaflets, 39%; stent frame, 17%; mitral valve, 21%). At least 1 complication of IE occurred in 87% of patients (heart failure in 68%). However, only 11% of patients underwent valve intervention (valve explantation and valve-in-valve procedure in 4 and 2 patients, respectively). The mortality rate in hospital was 47.2% and increased to 66% at the 1-year follow-up. IE complications such as heart failure (P=0.037) and septic shock (P=0.002) were associated with increased in-hospital mortality.

CONCLUSIONS

The incidence of IE at 1 year after TAVI was 0.50%, and the risk increased with the use of orotracheal intubation and a self-expandable valve system. Staphylococci and enterococci were the most common agents. Although most patients presented at least 1 complication of IE, valve intervention was performed in a minority of patients, and nearly half of the patients died during the hospitalization period.

[Percutaneous approaches to mitral valve disease]

Percutaneous approaches to mitral valve disease consist in modifications of existing surgical techniques, aiming to replicate the favourable outcomes of surgery, with less procedure-related risk, due to their less invasive nature. While some of these techniques are clearly indicated for the management of certain valve diseases, other appear as possible alternatives to surgery among patients deemed at high-risk or considered inoperable, or are still under clinical investigation. Major development of these percutaneous approaches is expected within the future, thus hopefully allowing treatment of a larger proportion of patients with mitral valve disease.

Long-term outcome after transcatheter aortic valve implantation

OBJECTIVE

To assess late outcome after transcatheter aortic valve implantation (TAVI) up to 6 years and to analyse its predictive factors with a particular emphasis on functional status. Very few data exist on the long-term results of TAVI, and these data are crucial for decision making.

METHODS

Between October 2006 and December 2009, 123 consecutive patients were discharged alive after TAVI in our institution. Mean age was 82±8 years, and 88% of patients were highly symptomatic in New York Heart Association (NYHA) class III-IV.

RESULTS

Follow-up was complete in 122 patients (99%). The overall 6-year survival rate was 31%±5%, the majority of deaths being non-cardiac. Predictive factors of late mortality were the presence of lower limb arteritis (p=0.009), a higher Charlson comorbidity index (p=0.03) and post-TAVI paraprosthetic aortic regurgitation ≥2/4 (p=0.01). Late outcomes according to Valve Academic Research Consortium-2 criteria were analysed, and the 5-year event-free survival rate was 28%±4%. Finally, the rate of good functional results, defined as survival in NYHA class I or II, was 32%±5% at 5-year follow-up. In the survivors, the EQ-5D questionnaire further confirmed the benefit in terms of quality of life.

CONCLUSIONS

About one-third of patients discharged alive after TAVI were alive at 6-year follow-up, and the survivors exhibited good functional results assessed by NYHA class and quality-of-life standardised evaluation.

The European Heart Academy

One of Dr Panos Vardas' visions for the European Society of Cardiology has been achieved.

Impact of aortic valve calcification, as measured by MDCT, on survival in patients with aortic stenosis: results of an international registry study

BACKGROUND

Aortic valve calcification (AVC) load measures lesion severity in aortic stenosis (AS) and is useful for diagnostic purposes. Whether AVC predicts survival after diagnosis, independent of clinical and Doppler echocardiographic AS characteristics, has not been studied.

OBJECTIVES

This study evaluated the impact of AVC load, absolute and relative to aortic annulus size (AVCdensity), on overall mortality in patients with AS under conservative treatment and without regard to treatment.

METHODS

In 3 academic centers, we enrolled 794 patients (mean age, 73 ± 12 years; 274 women) diagnosed with AS by Doppler echocardiography who underwent multidetector computed tomography (MDCT) within the same episode of care. Absolute AVC load and AVCdensity (ratio of absolute AVC to cross-sectional area of aortic annulus) were measured, and severe AVC was separately defined in men and women.

RESULTS

During follow-up, there were 440 aortic valve implantations (AVIs) and 194 deaths (115 under medical treatment). Univariate analysis showed strong association of absolute AVC and AVCdensity with survival (both, p < 0.0001) with a spline curve analysis pattern of threshold and plateau of risk. After adjustment for age, sex, coronary artery disease, diabetes, symptoms, AS severity on hemodynamic assessment, and LV ejection fraction, severe absolute AVC (adjusted hazard ratio [HR]: 1.75; 95% confidence interval [CI]: 1.04 to 2.92; p = 0.03) or severe AVCdensity (adjusted HR: 2.44; 95% CI: 1.37 to 4.37; p = 0.002) independently predicted mortality under medical treatment, with additive model predictive value (all, p ≤ 0.04) and a net reclassification index of 12.5% (p = 0.04). Severe absolute AVC (adjusted HR: 1.71; 95% CI: 1.12 to 2.62; p = 0.01) and severe AVCdensity (adjusted HR: 2.22; 95% CI: 1.40 to 3.52; p = 0.001) also independently predicted overall mortality, even with adjustment for time-dependent AVI.

CONCLUSIONS

This large-scale, multicenter outcomes study of quantitative Doppler echocardiographic and MDCT assessment of AS shows that measuring AVC load provides incremental prognostic value for survival beyond clinical and Doppler echocardiographic assessment. Severe AVC independently predicts excess mortality after AS diagnosis, which is greatly alleviated by AVI. Thus, measurement of AVC by MDCT should be considered for not only diagnostic but also risk-stratification purposes in patients with AS.

Respective performance of 18F-FDG PET and radiolabeled leukocyte scintigraphy for the diagnosis of prosthetic valve endocarditis

Echocardiography plays a key role in the diagnosis of infective endocarditis (IE) but can be inconclusive in patients in whom prosthetic valve endocarditis (PVE) is suspected. The incremental diagnostic value of (18)F-FDG PET and radiolabeled leukocyte scintigraphy in IE patients has already been reported. The aim of this study was to compare the respective performance of (18)F-FDG PET and leukocyte scintigraphy for the diagnosis of PVE in 39 patients.

METHODS

(18)F-FDG PET and leukocyte scintigraphy were performed on 39 consecutive patients admitted because of clinically suspected PVE and inconclusive echocardiography results. The results of (18)F-FDG PET and leukocyte scintigraphy were analyzed separately and retrospectively by experienced physicians masked to the results of the other imaging technique and to patient outcome. The final Duke-Li IE classification was made after a 3-mo follow-up.

RESULTS

Of the 39 patients, 14 were classified as having definite IE, 4 as having possible IE, and 21 as not having IE. The average interval between (18)F-FDG PET and leukocyte scintigraphy was 7 ± 7 d. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 93%, 71%, 68%, 94%, and 80%, respectively, for (18)F-FDG PET and 64%, 100%, 100%, 81%, and 86%, respectively, for leukocyte scintigraphy. Discrepancies between the results of (18)F-FDG PET and leukocyte scintigraphy occurred in 12 patients (31%). In patients with definite IE, 5 had true-positive (18)F-FDG PET results but false-negative leukocyte scintigraphy results. Of these 5 patients, 3 had nonpyogenic microorganism IE (Coxiella or Candida). Of patients for whom endocarditis had been excluded, 6 had true-negative leukocyte scintigraphy results but false-positive (18)F-FDG PET results. These 6 patients had been imaged in the first 2 mo after the last cardiac surgery. The last patient with a discrepancy between (18)F-FDG PET and leukocyte scintigraphy was classified as having possible endocarditis and had positive (18)F-FDG PET results and negative leukocyte scintigraphy results.

CONCLUSION

(18)F-FDG PET offers high sensitivity for the detection of active infection in patients with suspected PVE and inconclusive echocardiography results. Leukocyte scintigraphy offers a higher specificity, however, than (18)F-FDG PET for diagnosis of IE and should be considered in cases of inconclusive (18)F-FDG PET findings or in the first 2 mo after cardiac surgery.

Open issues in transcatheter aortic valve implantation. Part 1: patient selection and treatment strategy for transcatheter aortic valve implantation

An exponential increase in the use of transcatheter aortic valve implantation (TAVI) in patients with severe aortic stenosis has been witnessed over the recent years. The current article reviews different areas of uncertainty related to patient selection. The use and limitations of risk scores are addressed, followed by an extensive discussion on the value of three-dimensional imaging for prosthesis sizing and the assessment of complex valve anatomy such as degenerated bicuspid valves. The uncertainty about valvular stenosis severity in patients with a mismatch between the transvalvular gradient and the aortic valve area, and how integrated use of echocardiography and computed tomographic imaging may help, is also addressed. Finally, patients referred for TAVI may have concomitant mitral regurgitation and/or coronary artery disease and the management of these patients is discussed.

[The MitraClip procedure]

Mitral insufficiency is a frequently occurring valvular disease for which surgery is the reference treatment. A large number of patients are at high risk or even contraindicated for surgery due to comorbidities. The MitraClip procedure reproduces a surgical technique for mitral valve repair. Global experience includes over 12,000 patients and has been mainly reported in registries with limited follow-up. The degree of reduction of mitral insufficiency is less with the MitraClip than with surgery. Safety of the procedure is good in experienced centres. Most patients have functional improvement in the mid-term. The procedure may be considered in patients who are at high risk for surgery and remain symptomatic despite optimal medical treatment. In the future, more data are needed from longer follow-up and randomised trials. Both the technique and the equipment used in the procedure need to improve. In addition, it is hoped that combined percutaneous procedures will be available in the near future.