Grading mitral regurgitation using 4D flow CMR: Comparison to transthoracic echocardiography

OBJECTIVES

To determine the 4D Flow Cardiac Magnetic Resonance (CMR) thresholds that achieve the best agreement with transthoracic echocardiography (TTE) for grading mitral regurgitation (MR).

METHODS

We conducted a single-center prospective study of patients evaluated for chronic primary MR in 2016-2020. MR was evaluated blindly by TTE and 4D Flow CMR, respectively by two cardiologists and two radiologists with decades of experience. MR was graded with both methods as mild, moderate, or severe. 4D Flow CMR measurements included MR regurgitant volume per beat (RV) and mitral anterograde flow per beat (MF). RF was obtained as the ratio RV/MF. Additionally, MF was compared to left ventricular stroke volume (LVSV) by cine-CMR.

RESULTS

We included 33 patients in the initial cohort and 33 in the validation cohort. Inter-observer agreement was excellent for 4D Flow CMR ICC = .94 (95% CI, .86-.97, p < 0.0001). Using recommended TTE thresholds (30 ml, 60 ml, 30%, 50%), agreement was moderate for RV and RF. The best agreement between 4D Flow CMR and TTE was obtained with CMR thresholds of 20 and 40 ml for RV (κ = .93; 95% CI, .8-1) and 20% and 37% for RF (κ = .90; 95% CI, .7-.9). In the validation cohort, agreement between TTE and 4D Flow CMR was good with the optimal thresholds (κ = .78; 95% CI, .61-.94).

CONCLUSION

We propose CMR thresholds that provide a good agreement between TTE and CMR for grading MR. Further studies are needed to fully validate 4D-Flow CMR accuracy for primary MR quantification.

Contemporary Management of Severe Symptomatic Aortic Stenosis

BACKGROUND

There were gaps between guidelines and practice when surgery was the only treatment for aortic stenosis (AS).

OBJECTIVES

This study analyzed the decision to intervene in patients with severe AS in the EORP VHD (EURObservational Research Programme Valvular Heart Disease) II survey.

METHODS

Among 2,152 patients with severe AS, 1,271 patients with high-gradient AS who were symptomatic fulfilled a Class I recommendation for intervention according to the 2012 European Society of Cardiology guidelines; the primary end point was the decision for intervention.

RESULTS

A decision not to intervene was taken in 262 patients (20.6%). In multivariate analysis, the decision not to intervene was associated with older age (odds ratio [OR]: 1.34 per 10-year increase; 95% CI: 1.11 to 1.61; P = 0.002), New York Heart Association functional classes I and II versus III (OR: 1.63; 95% CI: 1.16 to 2.30; P = 0.005), higher age-adjusted Charlson comorbidity index (OR: 1.09 per 1-point increase; 95% CI: 1.01 to 1.17; P = 0.03), and a lower transaortic mean gradient (OR: 0.81 per 10-mm Hg decrease; 95% CI: 0.71 to 0.92; P < 0.001). During the study period, 346 patients (40.2%, median age 84 years, median EuroSCORE II [European System for Cardiac Operative Risk Evaluation II] 3.1%) underwent transcatheter intervention and 515 (59.8%, median age 69 years, median EuroSCORE II 1.5%) underwent surgery. A decision not to intervene versus intervention was associated with lower 6-month survival (87.4%; 95% CI: 82.0 to 91.3 vs 94.6%; 95% CI: 92.8 to 95.9; P < 0.001).

CONCLUSIONS

A decision not to intervene was taken in 1 in 5 patients with severe symptomatic AS despite a Class I recommendation for intervention and the decision was particularly associated with older age and combined comorbidities. Transcatheter intervention was extensively used in octogenarians.

Grading mitral regurgitation using 4D flow CMR: comparison to transthoracic echocardiography

Background

Mitral Regurgitation (MR) is currently primarily assessed using multiple transthoracic echocardiography (TTE) parameters. Two-dimensional Cardiac Magnetic Resonance (CMR) can be used in difficult cases but has limited agreement with TTE for quantifying MR. We hypothesized that 4D Flow CMR may help to quantify MR.

Purpose

To determine the 4D Flow CMR thresholds that achieve the best agreement with TTE for grading MR.

Methods

We conducted a single-center prospective study of patients evaluated for chronic primary MR in 2016–2020. MR was evaluated blindly by TTE and 4D Flow CMR respectively by two cardiologists and two radiologists with decades of experience. MR was graded with both methods as mild, moderate or severe. 4D Flow CMR measurements included MR regurgitant volume per beat (RV) and mitral anterograde flow per beat (MF). RF was obtained as the ratio RV/MF. Additionally, MF was compared to left ventricular stroke volume (LVSV) by cine-CMR.

Results

We included 33 patients in the initial cohort and 33 in the validation cohort. Inter-observer agreement was good for TTE and excellent for 4D Flow CMR. Agreement between MF and LVSV was excellent. Using recommended TTE thresholds (30 mL, 60 mL, 30%, 50%), agreement was moderate for RV and RF. The best agreement between 4D Flow CMR and TTE was obtained with CMR thresholds of 20 mL and 40 mL for RV (κ=0.93; 95% CI, 0.8–1) and 20% and 37% for RF (κ=0.90; 95% CI, 0.7–0.9). In the validation cohort, agreement between TTE and 4D Flow CMR was good with the optimal thresholds (κ= 0.78; 95% CI, 0.61–0.94).

Conclusion

We propose CMR thresholds that provide a good agreement between TTE and CMR for grading MR. Further studies are needed to fully validate 4D-Flow CMR accuracy for primary MR quantification.

Funding Acknowledgement

Type of funding sources: None. Quantification of MR using 4D Flow CMR

Grading mitral regurgitation using 4D flow CMR: comparison to transthoracic echocardiography

Funding Acknowledgements

Type of funding sources: None.

BACKGROUND

Mitral Regurgitation (MR) is currently primarily assessed using multiple transthoracic echocardiography (TTE) parameters. Two-dimensional Cardiac Magnetic Resonance (CMR) can be used in difficult cases but has limited agreement with TTE for quantifying MR. We hypothesized that 4D Flow CMR may help to quantify MR.

OBJECTIVES

To determine the 4D Flow CMR thresholds that achieve the best agreement with TTE for grading MR.

METHODS

 We conducted a single-center prospective study of patients evaluated for chronic primary MR in 2016-2020. MR was evaluated blindly by TTE and 4D Flow CMR respectively by two cardiologists and two radiologists with decades of experience. MR was graded with both methods as mild, moderate or severe. 4D Flow CMR measurements included MR regurgitant volume per beat (RV) and mitral anterograde flow per beat (MF). RF was obtained as the ratio RV/MF. Additionally, MF was compared to left ventricular stroke volume (LVSV) by cine-CMR.

RESULTS

 We included 33 patients in the initial cohort and 33 in the validation cohort. Inter-observer agreement was good for TTE and excellent for 4D Flow CMR. Agreement between MF and LVSV was excellent. Using recommended TTE thresholds (30 mL, 60 mL, 30%, 50%), agreement was moderate for RV and RF. The best agreement between 4D Flow CMR and TTE was obtained with CMR thresholds of 20 mL and 40 mL for RV (κ=0.93; 95%CI, 0.8-1) and 20% and 37% for RF (κ=0.90; 95%CI, 0.7-0.9). In the validation cohort, agreement between TTE and 4D Flow CMR was good with the optimal thresholds (κ= 0.78; 95%CI, 0.61-0.94).

CONCLUSION

We propose CMR thresholds that provide a good agreement between TTE and CMR for grading MR. Further studies are needed to fully validate 4D-Flow CMR accuracy for primary MR quantification.

P5874D Flow cardiac magnetic resonance quantification of mitral regurgitation, comparison with transthoracic echocardiography

Background

Mitral valve regurgitation (MR) is currently primarily assessed by a multiparametric approach with transthoracic echocardiography (TTE) that can be further completed by 2D Cardiac Magnetic Resonance (2D CMR) in case of doubt or poor acoustic window. TTE and 2D CMR have nevertheless imperfect agreement in terms of MR quantification. Time-resolved phase-contrast cardiac magnetic resonance imaging with flow-encoding in three spatial directions (4D Flow CMR) could help in MR quantification.

Purpose

Compare 4D Flow CMR quantification of MR with TTE using a multiparametric approach.

Methods

We conducted a monocentric, prospective study at the Institut Mutualiste Montsouris in Paris between November 2016 and 2017 including patients with chronic primitive MR. MR was evaluated with a multiparametric approach by two cardiologists with TTE and quantitatively by two radiologists with 4D Flow CMR. MR was classified as mild, moderate or severe and evaluated blindly with consensus in case of disagreement. 4D Flow CMR measurements consisted in quantifying MR regurgitant volume (RV) and MR regurgitant fraction (RF). 4D anterograde mitral flow was compared to left ventricular stroke volume using 2D-cine CMR.

Results

33 patients were included. Inter-observer agreement was good in TTE (kappa= 0.75 95% CI [0.57- 0.92]) and excellent in 4D Flow CMR (ICC= 0.94 95% CI [0.79–0.95]). Agreement with TTE was excellent using optimized thresholds (Mild: RV≤20mL RF≤20%, Moderate: RV=21–39mL RF=21–36%, Severe: RV≥40mL RF≥37%): kappa= 0.93 95% CI [0.8–1] for RV and kappa= 0.90 95% CI [0.7–0.9] for RF. A validation cohort confirmed that the 4D flow thresholds as determined were accurate for MR grading. Agreement between 4D anterograde mitral flow and 2D-cine CMR left ventricular stroke volume was also excellent (ICC= 0.92 95% CI [0.85–0.96]).

Conclusion

4D Flow CMR is a reliable tool for MR quantification. It provides direct quantitative evaluation of MR with low inter-observer variability. It may therefore be used as a gatekeeper before therapeutic decisions such as surgery.

Causes and consequences of cardiac fibrosis in patients referred for surgical aortic valve replacement

Aims

Cardiac fibrosis is associated with left ventricular (LV) remodelling and contractile dysfunction in aortic stenosis (AS). The fibrotic process in this condition is still unclear. The aim of this study was to determine the role of both local and systemic inflammation as underlying mechanisms of LV fibrosis and contractile dysfunction. The diagnostic values of 2D‐strain echocardiography and serum biomarkers in the evaluation of cardiac fibrosis in this condition were assessed through correlation analyses.

Methods and results

Patients with AS referred for surgical valve replacement were prospectively and consecutively included. They all had a comprehensive echocardiography including 2D strain. Blood samples were collected to measure cytokines and inflammatory biomarkers using Luminex bead‐based assays. A per‐surgical myocardial biopsy of the basal antero‐septal segment (S1) was performed. Serial sections of each biopsy were stained with Sirius red. Digital image analysis was used to quantify fibrosis. Immunostainings using specific antibodies against macrophage, glycoprotein (gp) 130, and interleukin 6 (IL‐6) were also performed. Patients were divided into tertiles reflecting the severity of fibrosis: mild, moderate, and severe load (TF1 to TF3). The mean age of the 58 included patients was 73 ± 11 years. Twenty‐four (43%) were in New York Heart Association III–IV. Mean aortic valve area was 0.8 ± 0.2 cm². Mean aortic stenosis peak velocity and mean gradient were respectively 4.5 ± 0.8 m/s and 54 ± 15 mmHg. The mean LV ejection fraction was 54 ± 12%, and the global LV longitudinal strain was −15 ± 4%. The mean S1 strain, corresponding to the biopsied region, was −10 ± 6% and was strongly correlated to fibrosis load (R = 0.83, P < 0.0001). TF3 was associated with higher mortality (P = 0.009), higher serum C‐reactive protein and IL‐6, and lower gp130 compared with the other tertiles (P < 0.05). IL‐6 and gp130 were expressed in the heart and respectively in the plasma membrane of macrophages and in the cytoplasm of both macrophages and cardiomyocytes. During follow‐up, three patients died and were all in the third fibrosis tertile.

Conclusions

We found a positive correlation between elevated inflammatory markers and degree of fibrosis load. These two parameters were associated with worse outcomes in patients with severe AS. Our results may be of interest especially in patients for whom a transcatheter aortic valve implantation is indicated and myocardial biopsy is not possible. Strategies aiming at preventing inflammation might be considered to decrease or limit the progression of cardiac fibrosis in patients followed for AS.

Systematic echocardiographic assessment of aortic regurgitation-what should the surgeon know for aortic valve repair?

Aortic valve (AV) repair is the preferred surgical treatment in young patients with aortic regurgitation (AR) and/or proximal aorta aneurysm, as noted in the recent European Society of Cardiology (ESC) guidelines. However, this surgical option is still underused in clinical practice. This emphasizes the need to build a heart team dedicated to AV repair with expert surgeons and echocardiographers. Surgical techniques are now standardized in their approaches to enhance the reproducibility and expansion of AV repair. The objective of this keynote is to also demonstrate the need for a standardized pre-pump intra-operative echocardiography protocol to fulfill surgeon's needs in providing a road map and predicting techniques to be used for an effective and durable repair.

Mitroflow LXA structural deterioration following aortic valve replacement: a single-center experience

BACKGROUND

Concerns have been previously raised regarding the potential early degeneration of the Mitroflow (Sorin Group Italia, Saluggia, Vercelli, Italy) bioprostheses. We aimed to evaluate our clinical experience with the Mitroflow LXA prosthesis for aortic valve replacement.

METHODS

We prospectively analyzed data from 227 consecutive patients (133 males, mean age 73.9±9.2 years) implanted with the Mitroflow LXA between February 2007 and October 2011. Follow-up data were obtained by contacting the referring cardiologists. Kaplan-Meier curves were constructed for all-cause mortality, valve related mortality and structural valve degeneration (SVD). Multivariable analysis was conducted to identify SVD predictors.

RESULTS

Median follow-up time was 54.2±37.9 months and completeness of follow-up was 95%. Overall mortality in the entire series was at 31% (N.=71) and mortality from cardiac or unknown causes at 20% (N.=46). SVD occurred in 24 patients (10%) (median delay between implantation and diagnosis: 62.6 (36.5) months). Reintervention was required in 20 cases (13 redo surgery, 7 percutaneous transcatheter valve intervention). The 8 years actuarial global survival was 54.7±4.9%, freedom from valve related mortality 67.5±4.9% and freedom from SVD 72±8%. The estimated freedom from SVD was significantly (P=0.007) longer in larger prosthesis (diameter >21 mm, 77±11%) compared to the smaller devices (≤21 mm, 59±13%.). Multivariate analysis identified smaller prostheses and age at implantation as independent predictors of SVD.

CONCLUSIONS

The Mitroflow LXA showed evidence of early SVD in this cohort. A close follow-up of these patients is strongly advised.

Prognostic value of QRS duration after transcatheter aortic valve implantation for aortic stenosis using the CoreValve

Transcatheter aortic valve implantation (TAVI) is effective in treating severe aortic stenosis in high-risk surgical patients. We evaluated the value of the QRS duration (QRSd) in predicting the mid-term morbidity and mortality after TAVI. We conducted a prospective cohort study of 91 consecutive patients who underwent TAVI using the CoreValve at our teaching hospital cardiology unit in 2008 to 2010 who survived to hospital discharge; 57% were women, and their mean age was 84 ± 7 years. The QRSd at discharge was used to classify the patients into 3 groups: QRSd ≤120 ms, n = 18 (20%); QRSd >120 ms but ≤150 ms, n = 30 (33%); and QRSd >150 ms, n = 43 (47%). We used 2 end points: (1) all-cause mortality and (2) all-cause mortality or admission for heart failure. After a median of 12 months, the normal-QRSd patients showed a trend toward, or had, significantly better overall survival and survival free of admission for heart failure compared with the intermediate-QRSd group (p = 0.084 and p = 0.002, respectively) and the long-QRSd group (p = 0.015 and p = 0.001, respectively). The factors significantly associated with all-cause mortality were the Society of Thoracic Surgeons score, aortic valve area, post-TAVI dilation, acute kidney injury, hospital days after TAVI, and QRSd at discharge. On multivariate analysis, QRSd was the strongest independent predictor of all-cause mortality (hazard ratio 1.036, 95% confidence interval 1.016 to 1.056; p <0.001) and all-cause mortality or heart failure admission (hazard ratio 1.025, 95% confidence interval 1.011 to 1.039; p <0.001). The other independent predictors were the Society of Thoracic Surgeons score, acute kidney injury, and post-TAVI hospital days. In conclusion, a longer QRSd after TAVI was associated with greater morbidity and mortality after 12 months. The QRSd at discharge independently predicted mortality and morbidity after TAVI.

Effect of transcatheter (via femoral artery) aortic valve implantation on the platelet count and its consequences

Decrease in blood platelet count has been described after percutaneous coronary intervention and surgical valve replacement, although no study has been performed in the setting of transcatheter aortic valve implantation (TAVI). The aim of this study was to address the incidence, mechanism, and impact of blood platelet count decrease after TAVI. One hundred forty-four consecutive patients (mean age 84 ± 7 years, 64 men) with severe symptomatic aortic stenosis who underwent TAVI from December 2007 to July 2011 were enrolled. Blood platelet count was recorded before and after aortic valve implantation. Decrease in blood platelet count was compared with in-hospital major adverse cardiovascular events (death, stroke, and major or life-threatening bleeding). Blood platelet count decreases occurred in all but 1 patient. The percentage of platelet count decrease averaged 34 ± 15% and was 24% greater than blood protein decrease. Decrease in platelet count was associated with a higher rate of prosthesis migration, longer x-ray and procedural times, and larger contrast amounts (230 ± 128 ml for the third tertile vs 170 ± 77 ml for the second and first tertiles, p = 0.0006), but no association was observed with regard to changes in bilirubin. In-hospital major adverse cardiovascular events (n = 50 [35%]) were observed more frequently in patients with severe platelet count decreases (21% for the first tertile, 35% for the second tertile, and 48% for the third tertile, p = 0.02). Finally, the percentage of blood platelet count decrease was the only predictor of in-hospital major adverse cardiovascular events (odds ratio 1.67, 95% confidence interval 1.05 to 2.67, p = 0.03). In conclusion, a decrease in platelet count is a common phenomenon after TAVI, and its severity is associated with poor outcomes.

Effect of local anesthetic management with conscious sedation in patients undergoing transcatheter aortic valve implantation

The present study sought to assess the effectiveness of local anesthesia with conscious sedation (LACS) during transcatheter aortic valve implantation (TAVI). On its introduction, TAVI was mostly performed with the patient under general anesthesia (GA); however, evidence supporting the use of less-invasive LACS has been increasing. The data from 174 consecutive patients who underwent TAVI by way of the femoral artery from December 2007 to December 2011 were analyzed. GA was mainly used in early phase of the study (n = 44); this was gradually shifted to LACS in the late phase (n = 130). The clinical outcomes were compared for those patients who received GA versus LACS. The incidence and causes of "LACS failure," defined as conversion to GA from LACS during TAVI, were also assessed. The rates of procedural success and 30-day mortality were not different between the 2 groups (93.3% vs 95.3%, p = 0.60; 6.7% vs 7.8%, p = 0.55, respectively). Although the clinical backgrounds of the patients showed differences, these results were not significant after adjusting for other influential confounders. The intensive care unit stay and hospital stay were longer in the GA group than in the LACS group (3.9 ± 2.2 vs 3.3 ± 1.5 days, p = 0.044; and 12.2 ± 8.3 vs 8.1 ± 6.5 days, p = 0.001, respectively). LACS failure occurred in 6 patients (4.6%), and the causes were multifactorial, as follows: cardiac tamponade in 2, cardiac arrest in 2, myocardial infarction in 1, and stroke in 1. In conclusion, transfemoral TAVI with the patient under LACS could be successfully performed in most patients, with the advantage of early recovery, although the perioperative risks involved in the TAVI procedure should be considered.

Comparison of effectiveness and safety of transcatheter aortic valve implantation in patients aged ≥90 years versus <90 years

In a fraction of patients aged ≥90 years, less-invasive transcatheter aortic valve implantation (TAVI) has been considered a therapeutic option for aortic stenosis under careful clinical screening. However, the safety and effectiveness using TAVI in such a population has not been fully elucidated. The aim of the present study was to investigate the feasibility of TAVI in nonagenarians. We prospectively enrolled 136 consecutive patients with severe aortic stenosis who were referred for TAVI. The procedural, early, and midterm clinical outcomes were compared between patients aged <90 years (n = 110, average age 82.3 ± 8.3 years) and ≥90 years (n = 26; average age 91.6 ± 1.9 years). A comparison of the baseline characteristics revealed that among patients aged ≥90 years, the prevalence of women (50% vs 81%, p <0.001) and the mean aortic valve gradient (45.5 ± 15.4 vs 56.3 ± 23.4 mm Hg, p = 0.005) were greater than those in patients aged <90 years. Major vascular complications occurred more frequently in patients ≥90 years (5% vs 19%, p = 0.022), although the rate of procedural success and 30-day and 6-month mortality were not different between the 2 age groups (96% vs 100%, p = 0.58; 6% vs 15%, p = 0.22; and 14% vs 27%, p = 0.14, respectively). The mortality rates were greater among patients aged ≥90 years. At 6 months, both groups of survivors were similar in symptom status, with a New York Heart Association classification less than class II (89% vs 84%, p = 0.68). The cumulative survival (median 13.4 ± 8.0 months of follow-up) was not significantly different between the 2 age groups (p = 0.22, log-rank test). In conclusion, even very elderly nonagenarians can experience acceptable clinical results and benefits after TAVI.

Incremental value of global longitudinal strain for predicting early outcome after cardiac surgery

AIMS

Global longitudinal strain (GLS) seems accurate for detecting subclinical myocardial dysfunction, and may therefore be used to improve risk stratification for cardiac surgery.

METHODS AND RESULTS

Longitudinal strain (by two-dimensional speckle tracking) was computed in 425 patients [mean age 67 ± 13 years, 69% male, left ventricular ejection fraction (LVEF) 51 ± 13%] referred for cardiac surgery [isolated coronary artery bypass graft (CABG) (n = 155), aortic valve surgery (n = 174), mitral surgery (n = 96)]. GLS (global-ε) was assessed for predicting early postoperative death. Despite a fair correlation between LVEF and global strain (r = -0.73, P < 0.0001), 40% of patients with preserved LVEF (defined as LVEF ≥50%) had abnormal global-ε (defined as global-ε >-16%): -12.8 ± 1.7%, range -15% to -8%. In patients with preserved LVEF, NT-proBNP level (983 vs. 541 pg/mL, P = 0.03), heart failure symptoms (NYHA class, 2.2 ± 0.9 vs. 1.9 ± 0.9, P = 0.02), and the need for prolonged (>48 h) inotropic support after surgery (33.3 vs. 21.2%, P = 0.03) were greater when global-ε was impaired. Importantly, despite similar EuroSCORE (9.7 ± 12 vs. 7.7 ± 9%, P = 0.2 for EuroSCORE I and 4.2 ± 6.2 vs. 3.4 ± 4.9%, P = 0.4 for EuroSCORE II), the rate of postoperative death was 2.4-fold (11.8 vs. 4.9%, P = 0.04) in patients with preserved LVEF when global-ε was impaired. Multivariate analysis showed that global-ε is an independent predictor for early postoperative mortality [odds ratio = 1.10 (1.01-1.21)] after adjustment to EuroSCORE.

CONCLUSION

GLS has an incremental value over LVEF for risk stratification in patients referred for cardiac surgery.

European Association of Echocardiography recommendations for the assessment of valvular regurgitation. Part 2: mitral and tricuspid regurgitation (native valve disease)

Mitral and tricuspid are increasingly prevalent. Doppler echocardiography not only detects the presence of regurgitation but also permits to understand mechanisms of regurgitation, quantification of its severity and repercussions. The present document aims to provide standards for the assessment of mitral and tricuspid regurgitation.

Risk Score for Predicting Outcome in Patients With Asymptomatic Aortic Stenosis

Background— The management of patients with asymptomatic severe aortic stenosis remains controversial. We sought to develop a continuous risk score for predicting the midterm development of symptoms or adverse events in this setting.

Methods and Results— We prospectively followed 107 patients with asymptomatic aortic stenosis (aged 72 years [63 to 77]; 35 women; aortic-jet velocity, 4.1 m/s [3.5 to 4.4]) at a single center in France. Predefined end points for assessing outcome were the occurrence within 24 months of death or aortic valve replacement necessitated by symptoms or by a positive exercise test. Variables independently associated with outcome were used to build a score that was validated in an independent cohort of 107 patients from Belgium. Independent predictors of outcome were female sex, peak aortic-jet velocity, and B-type natriuretic peptide at baseline. Accordingly, the score could be calculated as follows: Score=[peak velocity (m/s)×2]+(natural logarithm of B-type natriuretic peptide×1.5)+1.5 (if female sex). Event-free survival after 20 months was 80% for patients within the first score quartile compared with only 7% for the fourth quartile. Areas under the receiver operating characteristic curve for the score were 0.90 and 0.89 in the development and validation cohorts, respectively.

Conclusions— If further validation is achieved, this score may be useful to predict outcome in individual patients with asymptomatic aortic stenosis to select those who might benefit from early surgery.

Outcome after aortic valve replacement for low-flow/low-gradient aortic stenosis without contractile reserve on dobutamine stress echocardiography

OBJECTIVES

This study investigated whether aortic valve replacement (AVR) is associated with improved survival in patients with severe low-flow/low-gradient aortic stenosis (LF/LGAS) without contractile reserve (CR) on dobutamine stress echocardiography (DSE).

BACKGROUND

Patients with LF/LGAS without CR have a high mortality rate with conservative therapy. The benefit of AVR in this subset of patients remains controversial.

METHODS

Eighty-one consecutive patients with symptomatic calcified LF/LGAS (valve area <or=1 cm(2), left ventricular ejection fraction <or=40%, mean pressure gradient [MPG] <or=40 mm Hg) without CR on DSE were enrolled. Absence of CR was defined as the absence of increase in stroke volume of >or=20% compared with the baseline value. Multivariable analysis and propensity scores were used to compare survival according to whether or not AVR was performed (n = 55).

RESULTS

Five-year survival was higher in AVR patients compared with medically managed patients (54 +/- 7% vs. 13 +/- 7%, p = 0.001) despite a high operative mortality of 22% (n = 12). An AVR was independently associated with lower 5-year mortality (adjusted hazard ratio from 0.16 to 5.21 varying with time [95% confidence interval: 0.12-3.16 to 0.21-8.50], p = 0.00026). In 42 propensity-matched patients, 5-year survival was markedly improved by AVR (65 +/- 11% vs. 11 +/- 7%, p = 0.019). Associated bypass surgery (p = 0.007) and MPG <or=20 mm Hg (p = 0.035) were independently predictive of operative mortality. Late survival after AVR (excluding operative death) was 69 +/- 8% at 5 years.

CONCLUSIONS

In patients with LF/LGAS without CR on DSE, AVR is associated with better outcome compared with medical management. Surgery should not be withheld from this subset of patients solely on the basis of lack of CR on DSE.

Low-gradient aortic stenosis: impact of prosthesis-patient mismatch on survival

AIMS

To assess the prognostic impact of prosthesis-patient mismatch (PPM) in a large consecutive series of patients operated for low-gradient aortic stenosis (AS).

METHODS AND RESULTS

Outcomes after surgery for low-gradient AS were prospectively assessed in 152 consecutive patients from seven institutions. There were 113 men (74%); mean age was 72 years (64-76); valve area, 0.7 cm(2) (0.6-0.8); left ventricular (LV) ejection fraction 0.31 (0.25-0.37) and baseline mean transaortic pressure gradient (MPG), 30 mmHg (25-35) Among 139 patients with available prosthetic valve effective orifice area (EOA), PPM (defined by an indexed EOA < or = 0.85 cm(2)/m(2)) was present in 79 patients (57%) and had no significant impact on post-operative mortality. Independent predictors of overall mortality were LV contractile reserve [hazard ratio (HR) 0.52; 95% confidence interval (CI) 0.35-0.78; P = 0.002], associated coronary artery bypass grafting (HR 1.87; 95% CI 1.24-2.82; P =0.003), baseline MPG (per 1 mmHg decrease to 10 mmHg; HR 1.03; 95% CI 1.01-1.06; P = 0.021), previous cancer (HR 2.13; 95% CI 1.05-4.29; P = 0.037), and logistic EuroSCORE (per 1% increase; HR 1.02; 95% CI 1.01-1.04; P = 0.040). CONCLUSION In this large multicentre series of patients with low-gradient AS, we found that PPM (moderate in most cases) had no influence on post-operative mortality. Therefore, the performance of more complex interventions in order to avoid moderate PPM may not be justified in the setting of low-gradient AS, because their higher risk probably outweighs the expected benefit.

Effects of surgery on ischaemic mitral regurgitation: A prospective multicenter registry (SIMRAM registry)

AIMS

Functional ischaemic mitral regurgitation (IMR) is common in patients with ischaemic left ventricular dysfunction undergoing coronary artery bypass surgery. Although the presence of IMR negatively affects prognosis, the additional benefit of valve repair is debated, particularly with mild IMR at rest. Exercise echocardiography may help identify a subset of patients at higher risk of cardiovascular events by revealing the dynamic component of IMR.

METHODS

A large prospective, multicentre, non-randomized registry is designed to evaluate the effects of surgery on IMR at rest and on its dynamic component at exercise (z). SIMRAM will enrol approximately 550 patients with IMR in up to 17 centres with clinical and exercise follow-up for 1 year. Three sets of outcomes will be prospectively assessed and several hypotheses will be tested including determinants of adverse outcome and progressive left ventricular remodeling, efficacy of treatment and role of ischaemia on the dynamic consequences of IMR. Enrolment began in November 2006 and is expected to end by early 2008.

Influence of Preoperative Left Ventricular Contractile Reserve on Postoperative Ejection Fraction in Low-Gradient Aortic Stenosis

Background— Dobutamine stress hemodynamics (DSH) has the potential to stratify operative risk in low-gradient aortic stenosis (AS), but little is known about the relation between left ventricle contractile reserve and postoperative left ventricular ejection fraction (LVEF). We sought to assess the value of DSH to predict postoperative improvement in LVEF.

Methods and Results— Sixty-six consecutive patients with symptomatic severe AS (aortic valve area ≤1 cm 2 ), LVEF ≤40%, and mean pressure gradient ≤40 mm Hg prospectively enrolled in the French multicenter study on low-gradient AS and who survived to aortic valvular replacement (AVR) were included. Preoperative contractile reserve was present in 46 patients (group I; 70%) and absent in 20 patients (group II; 30%). In the overall sample, 58% of patients improved by 2 New York Heart Association (NYHA) classes after AVR. Mean LVEF improved from 29±6% to 47±11% ( P <0.0001). LVEF improved by ≥10 EF units in 38 patients (83%) in group I and in 13 patients (65%) in group II. Mean LVEF improvement was similar in the 2 groups (19±10% versus 17±11%; P =0.54). On multivariable analysis, multivessel coronary artery disease ( P =0.05) and baseline mean transaortic pressure gradient ( P =0.01) were related to LVEF improvement, whereas contractile reserve was not.

Conclusions— LVEF increases in the majority of patients with low-gradient AS who survive after AVR. Although the absence of contractile reserve on DSH is related to high operative mortality, it does not predict the absence of LVEF recovery in patients surviving to AVR. These data further support the concept that surgery should not be contraindicated on the basis of absence of contractile reserve alone.

Factors associated with dyspnea in adult patients with sickle cell disease

OBJECTIVE

The aim of this prospective study was to determine the cardiorespiratory factors associated with dyspnea in patients with sickle cell SS-hemoglobin disease, with a specific interest in lung vascular involvement.

MEASUREMENTS

Forty-nine patients (29 women and 20 men; mean [+/- SD] age: women, 29 +/- 6 years; men, 31 +/- 11 years) underwent direct evaluations (Borg scale evaluation during a 6-min walk test) and indirect evaluations (modified Medical Research Council [MRC]score) of their dyspnea, pulmonary function tests (PFTs) [spirometry, volumes, diffusing capacity of the lung for carbon monoxide (Dlco), diffusing capacity of the alveolar-capillary membrane, and pulmonary capillary blood volume measurements], echocardiography, and biological evaluation.

RESULTS

Thirty-four patients complained of significant breathlessness (MRC score, > 1). Indirect and direct evaluations of dyspnea were correlated. PFT results depicted a very mild restrictive pattern (mean total pulmonary capacity, 86 +/- 11% predicted) and an impairment of Dlco (mean Dlco corrected for the degree of anemia, 69 +/- 13% predicted). The statistical analysis demonstrated that dyspnea and exercise performance were closely linked to indexes of Dlco but not with any echocardiographic or biological measure including anemia. Nevertheless, only approximately 25% of the variability was explained by these associations. Despite having a similar history of vasoocclusive crisis events, women had more severe anemia, dyspnea, decreases in Dlco (corrected for the degree of anemia), and a higher capillary blood volume (corrected for alveolar volume) than men.

CONCLUSION

Lung vascular disease contributes to dyspnea and the exercise limitation of patients with sickle cell disease. A sequential assessment of Dlco would therefore constitute one of the objective functional end points for follow-up studies of these patients.

[Echocardiography and mechanical complications of recent myocardial infarction]

The constantly advancing technology of echocardiography and its widespread usage in the intensive care unit has made it a routine examination in patients with acute myocardial infarction. It has become the reference method for diagnosis and monitoring of certain complications such as pericardial effusion, intra-ventricular thrombosis, ventricular aneurysm and mitral regurgitation. The echocardiographic description of these complications dates back to the 1980s during which prospective studies accurately described the principal abnormalities. These descriptions have not been much improved upon with the advent of new technology. On the other hand, the frequency of these complications assessed in an era when reperfusion by thrombolysis or primary angioplasty was much less common than today, has considerably decreased.

[Dobutamine hemodynamics for aortic stenosis with left ventricular dysfunction]

Patients with aortic stenosis (AS) and left ventricular (LV) systolic dysfunction have a poor short-term prognosis. In this setting, the decrease in transaortic gradients has an independent prognostic value for operative risk and long-term outcome. The 2 main issues for these patients are: (1) The real severity of AS; (2) How to stratify operative risk and evaluate long-term prognosis. Dobutamine Hemodynamics has the potential to address these issues. In case of relative AS, valve area is increased by dobutamine (final valve area > 1.2 cm2 with a mean pressure gradient <30 mmHg); on the basis of published data, medical treatment is justified in this case. Left ventricular contractile reserve is defined an increase in stroke volume, by 20% or more, under dobutamine. Operative risk is between 5 and 11% in case of LV contractile reserve and long-term outcome is improved by surgery in this case. In contrast, operative risk varies from 30 to 60% in case of exhausted reserve; this risk is also determined by other factors such as the presence of coronary artery disease and associated comorbidities. All these parameters are factored into risk-benefit analysis in order to determine the best therapeutic approach for each patient.

Functional Assessment of Mitral Regurgitation by Transthoracic Echocardiography Using Standardized Imaging Planes

OBJECTIVES

We sought to assess the value of transthoracic echocardiography (TTE) using standardized imaging planes for the functional analysis of mitral regurgitation (MR) as well as for postoperative outcome implications.

BACKGROUND

The feasibility of mitral valve repair is based on functional assessment of MR, mainly by transesophageal echocardiography (TEE). Considering the recent advances in TTE imaging, the incremental value of TEE in this setting needs to be re-examined.

METHODS

Consecutive patients (n = 279; 181 men; median age 68 years [quartiles, 61 to 74]) who underwent surgery for MR were enrolled prospectively in two tertiary care centers. The accuracy of TTE (harmonic imaging) versus TEE for functional assessment of MR was evaluated against surgical findings.

RESULTS

Valve repair (n = 237 patients, 85%) or replacement (n = 42) was predicted accurately by TTE in 97% of cases; TEE added significant information for only two patients. In the subgroup of degenerative MR (n = 190), agreement with surgical findings for the localization of prolapsed segments was 91% for TTE (kappa, 0.81) and 93% for TEE (kappa, 0.85) without incremental value of TEE (p = 0.40). Patients with single prolapse of the middle posterior scallop (P2) had a better postoperative outcome as compared with patients who had non-P2 lesions (p = 0.008). Furthermore, mitral replacement predicted by TTE was an independent predictor for postoperative long-term mortality (odds ratio 5.7, 95% confidence interval 1.97 to 16.4, p = 0.001).

CONCLUSIONS

In experienced hands, functional assessment of MR by TTE can predict accurately valve repairability and has a strong influence on postoperative outcome. Thus, in most cases preoperative TEE is not mandatory, provided intraoperative TEE is performed.

[Stress echo and valvular heart disease]

Stress echo has already been validated in some forms of valvular heart disease, especially in calcific aortic stenosis with low cardiac output and dynamic mitral regurgitation (MR) of valvular heart disease. Stress Doppler haemodynamics is a term used to differentiate these new indications from that of segmental wall analysis of the left atrium in ischaemic heart disease. In calcific aortic stenosis with low output, the haemodynamics with low dose dobutamine allows assessment of the real severity of the aortic stenosis and identification of the rare cases with mild stenosis: the principal indication remains the assessment of operative risk and long-term prognosis by the study of left ventricular contractile reserve. In cases of ischaemic left ventricular systolic dysfunction, the presence of mild mitral regurgitation (regurgitant surface area >20 mm2 at rest) is a poor prognostic factor. The dynamic character of mitral regurgitation is related to left ventricular remodelling which leads to deformation of the valvular apparatus (mitral tenting). Dynamic mitral regurgitation (regurgitant orifice area >13 mm2 on exercise) is a powerful prognostic factor, the role of which has recently been demonstrated in the genesis of acute pulmonary oedema. the other indications of stress haemodynamics are under validation, mainly the assessment of exercise capacity and valvular compliance in mitral stenosis or asymptomatic aortic stenosis.

Usefulness of plasma B-type natriuretic peptide in predicting recurrence of atrial fibrillation one year after external cardioversion

After successful external cardioversion, the rate of recurrence of atrial fibrillation remains high. The hypothesis that plasma B-type natriuretic peptide could predict the recurrence of atrial fibrillation at 1 year was tested. Plasma B-type natriuretic peptide was measured in 66 consecutive asymptomatic patients who underwent external cardioversion for atrial fibrillation. Twelve-lead electrocardiograms were obtained at 1 year. Sinus rhythm was maintained in 55% of patients. The independent predictors of the recurrence of atrial fibrillation at 1 year were a history of atrial fibrillation, plasma B-type natriuretic peptide, and the energy delivered for conversion. In patients without symptoms of heart failure, plasma B-type natriuretic peptide is an independent predictor of the recurrence of atrial fibrillation.

Assessment of myocardial reperfusion after myocardial infarction using automatic 3-dimensional quantification and template matching

Assessment of perfusion defect extent is essential for determining prognosis after a myocardial infarction (MI), but quantification methods usually rely on segmental analysis, which may lack accuracy. We present an automated voxel-based and template-based approach for precise quantification of perfusion defect extent and reperfusion evolution.

METHODS

Coronary angiography and stress/reinjection (201)Tl tomography were performed prospectively on 49 patients with recent MI (45 men; mean age +/- SD, 54 +/- 10 y), before and 3 mo after revascularization (40 angioplasties and 9 bypasses). Perfusion defect extent was quantified using expert 16-segment visual scoring of the slices and a 3-dimensional (3D) method with spatial normalization between times 1 and 2. Briefly, the latter automatically extracted myocardial edges, matched them to a reference template, and compared the perfusion intensity in each voxel with the intensity of the corresponding voxel in a control population of 100 healthy subjects.

RESULTS

Reocclusion occurred in 12 patients within 3 mo of surgery (all had undergone angioplasty). The perfusion gain between times 1 and 2, assessed by visual analysis, was significantly higher in permeable patients than in reoccluded patients: 12.4% +/- 13.3% and 2.3% +/- 8.2% of the initial stress defect, respectively (P = 0.02). Proportional gains, measured with the quantitative 3D method, were 4.5% +/- 3.6% and 1.9% +/- 2.7%, respectively (P = 0.02). Furthermore, the 3D method allowed measurement within the initial ischemic defect (reversible part of the stress defect at time 1), the extent of myocardium whose perfusion improved at time 2 (reperfusion), and the extent of myocardium whose perfusion remained unchanged (residual ischemia). A voxel-by-voxel analysis of these regions revealed that the proportion of reperfusion was significantly higher in permeable patients than in reoccluded patients: 60.0% +/- 21.3% versus 40.0% +/- 22.5%, respectively (P = 0.008). This was cumbersome to quantify using visual analysis and did not reach statistical significance, likely because of segmental division (partial-volume effect) and absence of spatial normalization.

CONCLUSION

The 3D voxel-based quantification allows satisfying assessment of reperfusion 3 mo after MI. Moreover, the automated analysis using spatial normalization should facilitate a reproducible assessment of large populations over time.

[Localization of mitral valve prolapse zones with multiplane transesophageal echocardiography]

CONTEXT

There are few literature data on the localization and extent of mitral valve prolapse zones with transesophageal echocardiography (TEE).

AIM OF THE STUDY

To assess a standardized imaging technique for the localization and extent determination of prolapse zones, based on 3 easily reproducible views with multiplane TEE.

METHODS

Seventy patients with severe mitral regurgitation due to valve prolapse requiring a multiplane TEE prior to surgery (valve repair or replacement) have been retrospectively assessed. Data of TEE on the localization and extent of prolapse zones have been confronted to per-operative anatomical observations (gold standard).

RESULTS

The sensitivity of TEE for the identification of isolated P2 prolapse, prolapse with commisural extension, isolated rupture of the posterior commisure and bi-valvular prolapses were respectively at 96%, 88%, 86% and 80%. The corresponding specificities were from 98% to 100%.

CONCLUSIONS

The use of a standardized technique with the use of 3 easily reproducible incidences with multiplane TEE allows a precise definition of the localization and extent of mitral valve prolapse zones, in order to potentially indicate valve repair.