The MIDA Mortality Risk Score: development and external validation of a prognostic model for early and late death in degenerative mitral regurgitation

Aims

In degenerative mitral regurgitation (DMR), lack of mortality scores predicting death favours misperception of individual patients' risk and inappropriate decision-making.

Methods and results

The Mitral Regurgitation International Database (MIDA) registries include 3666 patients (age 66 ± 14 years; 70% males; follow-up 7.8 ± 5.0 years) with pure, isolated, DMR consecutively diagnosed by echocardiography at tertiary (European/North/South-American) centres. The MIDA Score was derived from the MIDA-Flail-Registry (2472 patients with DMR and flail leaflet-Derivation Cohort) by weighting all guideline-provided prognostic markers, and externally validated in the MIDA-BNP-Registry (1194 patients with DMR and flail leaflet/prolapse-Validation Cohort). The MIDA Score ranged from 0 to 12 depending on accumulating risk factors. In predicting total mortality post-diagnosis, the MIDA Score showed excellent concordance both in Derivation Cohort (c = 0.78) and Validation Cohort (c = 0.81). In the whole MIDA population (n = 3666 patients), 1-year mortality with Scores 0, 7-8, and 11-12 was 0.4, 17, and 48% under medical management and 1, 7, and 14% after surgery, respectively (P < 0.001). Five-year survival with Scores 0, 7-8, and 11-12 was 98 ± 1, 57 ± 4, and 21 ± 10% under medical management and 99 ± 1, 82 ± 2, and 57 ± 9% after surgery (P < 0.001). In models including all guideline-provided prognostic markers and the EuroScoreII, the MIDA Score provided incremental prognostic information (P ≤ 0.002).

Conclusion

The MIDA Score may represent an innovative tool for DMR management, being able to position a given patient within a continuous spectrum of short- and long-term mortality risk, either under medical or surgical management. This innovative prognostic indicator may provide a specific framework for future clinical trials aiming to compare new technologies for DMR treatment in homogeneous risk categories of patients.

How Should Very Severe Aortic Stenosis Be Defined in Asymptomatic Individuals?

See Article by Kanamori et al.

P6474Hidden in plain sight: diastolic blood pressure, resting heart rate and physical examination are independent predictors of mortality in chronic aortic regurgitation

Background

In patients with hemodynamically-significant chronic aortic valve regurgitation (AR), the prognostic significance of routinely-measured diastolic blood pressure (DBP), resting heart rate (RHR) and physical examination signs of heart failure (HF), is unknown.

Purpose

To investigate the association of DBP, RHR and HF signs, with all-cause mortality.

Methods

This retrospective cohort study included all consecutive patients with moderately-severe or severe AR within a tertiary-referral center from 2006–2017. Patients with ≥moderate aortic stenosis and those with ≥moderate mitral stenosis/regurgitation were excluded.

Results

Of 820 patients (age 59±17 years; 82% men) with DBP 64±13mmHg and RHR 64±12bpm, followed for 5.5±3.5 years, 104 died under medical management and 400 underwent aortic valve surgery (AVS). In multivariable analysis, DBP (adjusted-hazard ratio [HR] 0.82 [0.68–0.98] p=0.031, per 10mmHg increase), RHR (adjusted HR 1.2 [1.01–1.41] p=0.034 per 10bpm increase), and any HF signs (adjusted HR 1.66 [1.04–2.61] p=0.032) were associated with all-cause death independently of demographics, comorbidities, and guideline-derived surgical triggers. Mortality increased in a J-curve fashion for DBP starting at 70 mmHg and peaking at 55 mmHg (Fig A,C), and in a linear fashion for RHR starting at 60bpm (Fig B, D). The association persisted after additional adjustment for medications, presence of hypertension and time-dependent AVS. A clinical score combining DBP, RHR and any HF signs increased the mortality risk-discrimination of demographics and comorbidities from 74% to 79% (p=0.01), and from 79% to 82% after addition of surgical triggers (p=0.04).

Figure. Risk of death by DBP and RHR

Conclusions

In patients with AR, routinely-measured vital signs and physical examination are strongly associated with all-cause mortality; lower DBP, higher RHR and any HF signs are independent predictors of mortality, and provide incremental mortality risk-discriminating value to baseline demographics, comorbidities and guideline-derived surgical triggers. These findings represent a clinical paradigm shift and have guideline implications.

Atrial fibrillation is not an independent predictor of outcome in patients with aortic stenosis

OBJECTIVES

To examine the prognostic significance of atrial fibrillation (AF) versus sinus rhythm (SR) on the management and outcomes of patients with severe aortic stenosis (AS).

METHODS

1847 consecutive patients with severe AS (aortic valve area ≤1.0 cm² and aortic valve systolic mean Doppler gradient ≥40 mm Hg or peak velocity ≥4 m/s) and left ventricular ejection fraction ≥50% were identified. The independent association of AF and all-cause mortality was assessed.

RESULTS

Age was 76±11 years and 46% were female; 293 (16%) patients had AF and 1554 (84%) had SR. In AF, 72% were symptomatic versus 71% in SR. Survival rate at 5 years for AF (41%) was lower than SR (65%) (age- and sex-adjusted HR=1.66 (1.40-1.98), p<0.0001). In multivariable analysis, factors associated with mortality included age (HR per 10 years=1.55 (1.42-1.69), p<0.0001), dyspnoea (HR=1.58 (1.33-1.87), p<0.0001), ≥ moderate mitral regurgitation (HR=1.63 (1.22-2.18), p=0.001), right ventricular systolic dysfunction (HR=1.88 (1.52-2.33), p<0.0001), left atrial volume index (HR per 10 mL/m²=1.13 (1.07-1.19), p<0.0001) and aortic valve replacement (AVR) (HR=0.44 (0.38-0.52), p<0.0001). AF was not a predictor of mortality independent of variables strongly correlated HR=1.02 (0.84-1.25), p=0.81). The 1-year probability of AVR following diagnosis of severe AS was lower in AF (49.8%) than SR (62.5%) (HR=0.73 (0.62-0.86), p<0.001); among patients with AF not referred for AVR, symptoms were frequently attributed to AF instead of AS.

CONCLUSION

AF was associated with poor prognosis in patients with severe AS, but apparent differences in outcomes compared with SR were explained by factors other than AF including concomitant cardiac abnormalities and deferral of AVR due to attribution of cardiac symptoms to AF.

Aortic Valve Surgery in Nonelderly Patients: Insights Gained From AVIATOR

Aortic valve surgery in non-elderly patients represents a very challenging patient population. The younger the patient is at the point of aortic valve intervention, the longer their anticipated life expectancy will be, with longer exposure to valve-related complications and risk for re-operation. Although the latest international guidelines recommend aortic valve repair in patients with aortic valve insufficiency, what we see in the real world is that the vast majority of these aortic valves are replaced. However, current prosthetic valves has now been shown to lead to significant loss of life expectancy for non-elderly patients up to 50% for patients in their 40s undergoing mechanical aortic valve replacement. Bioprostheses carry an even worse long-term survival, with higher rates of re-intervention. The promise of trans-catheter valve-in-valve technology is accentuating the trend of bioprosthetic implantation in younger patients, without yet the appropriate evidence. In contrast, aortic valve repair has shown excellent outcomes in terms of quality of life, freedom from re-operation and freedom from major adverse valve-related events with similar life expectancy to general population as it is also found for the Ross procedure, the only available living valve substitute. We are at a time when the paradigm of aortic valve surgery needs to change for the better. To better serve our patients, we must acquire high quality real-world evidence from multiple centers globally - this is the vision of the AVIATOR registry and our common responsibility.

The unique mechanism of functional mitral regurgitation in acute myocardial infarction: a prospective dynamic 4D quantitative echocardiographic study

AIMS

Mechanisms of chronic ischaemic mitral regurgitation (IMR) are well-characterized by apically tethered leaflet caused by papillary muscles (PMs) displacement and adynamic mitral apparatus. We investigated the unique geometry and dynamics of the mitral apparatus in first acute myocardial infarction (MI) by using quantified 3D echocardiography.

METHODS AND RESULTS

We prospectively performed 3D echocardiography 2.3 ± 1.8 days after first MI, in 174 matched patients with (n = 87) and without IMR (n = 87). 3D echocardiography of left ventricular (LV) volumes and of mitral apparatus dynamics throughout cardiac cycle was quantified. Similar mitral quantification was obtained at chronic post-MI stage (n = 44). Mechanistically, acute IMR was associated with larger and flatter annulus (area 9.29 ± 1.74 cm2 vs. 8.57 ± 1.94 cm2, P = 0.002, saddle shape 12.7 ± 4.5% vs. 15.0 ± 4.6%, P = 0.001), and larger tenting (length 6.36 ± 1.78 mm vs. 5.60 ± 1.55 mm, P = 0.003) but vs. chronic MI, mitral apparatus displayed smaller alterations (all P < 0.01) and annular size, PM movement remained dynamic (all P < 0.01). Specific to acute IMR, without PM apical displacement (P > 0.70), greater separation (21.7 ± 4.9 mm vs. 20.0 ± 3.4 mm, P = 0.01), and widest angulation of PM (38.4 ± 6.2° for moderate vs. 33.5 ± 7.3° for mild vs. 31.4 ± 6.3° for no-IMR, P = 0.0009) wider vs. chronic MI (P < 0.01).

CONCLUSIONS

3D echocardiography of patients with first MI provides insights into unique 4D dynamics of the mitral apparatus in acute IMR. Mitral apparatus remained dynamic in acute MI and distinct IMR mechanism in acute MI is not PM displacement seen in chronic IMR but separation and excess angulation of PM deforming the mitral valve, probably because of sudden-onset regional wall motion abnormality without apparent global LV remodelling. This specific mechanism should be considered in novel therapeutic strategies for IMR complicating acute MI.

Circulating Osteogenic Progenitor Cells in Mild, Moderate, and Severe Aortic Valve Stenosis

The aim of this study was to characterize endothelial progenitor cells with osteoblastic phenotype (EPC-OCNs) and their role in individuals with varying degrees of aortic stenosis (AS). Peripheral blood mononuclear cells retrieved from blood samples of individuals with mild (n=40), moderate (n=35), or severe (n=103) AS from September 16, 2008, through March 30, 2015, were analyzed by flow cytometry for the EPC surface markers CD34, CD133, and kinase insert domain receptor (KDR) and the osteoblastic cell surface marker OCN. Levels of EPC-OCNs were correlated with AS severity and calcifications. Patients with severe AS had significantly elevated numbers of total circulating EPC-OCNs, including the EPC-OCN subtypes CD133⁺/OCN⁺, CD34⁺/CD133⁺/OCN⁺, and CD133⁺/KDR⁺/OCN⁺, compared with those with mild AS. Individuals with moderate AS also had significantly increased numbers of the circulating progenitor cell CD133⁺/OCN⁺ compared with patients with mild AS. There was a significant association between total circulating EPC-OCN levels and aortic valve (AV) calcification, AV mean gradient, and AV area measured by echocardiography. In summary, this study found the presence of circulating EPC-OCNs in patients with progressive AV stenosis. These findings might support the potential role for EPC-OCNs in the progression of AV stenosis and calcification.

Screening for cardiac contractile dysfunction using an artificial intelligence-enabled electrocardiogram

Asymptomatic left ventricular dysfunction (ALVD) is present in 3-6% of the general population, is associated with reduced quality of life and longevity, and is treatable when found^1-4. An inexpensive, noninvasive screening tool for ALVD in the doctor's office is not available. We tested the hypothesis that application of artificial intelligence (AI) to the electrocardiogram (ECG), a routine method of measuring the heart's electrical activity, could identify ALVD. Using paired 12-lead ECG and echocardiogram data, including the left ventricular ejection fraction (a measure of contractile function), from 44,959 patients at the Mayo Clinic, we trained a convolutional neural network to identify patients with ventricular dysfunction, defined as ejection fraction ≤35%, using the ECG data alone. When tested on an independent set of 52,870 patients, the network model yielded values for the area under the curve, sensitivity, specificity, and accuracy of 0.93, 86.3%, 85.7%, and 85.7%, respectively. In patients without ventricular dysfunction, those with a positive AI screen were at 4 times the risk (hazard ratio, 4.1; 95% confidence interval, 3.3 to 5.0) of developing future ventricular dysfunction compared with those with a negative screen. Application of AI to the ECG-a ubiquitous, low-cost test-permits the ECG to serve as a powerful screening tool in asymptomatic individuals to identify ALVD.