Mitral Annulus Calcium Score

Scoring model based on cardiac CT and clinical factors to predict early good mitral valve repair in rheumatic mitral disease

OBJECTIVE

We aimed to evaluate the mitral valve calcification and mitral structure detected by cardiac computed tomography (cardiac CT) and establish a scoring model based on cardiac CT and clinical factors to predict early good mitral valve repair (EGMR) and guide surgical strategy in rheumatic mitral disease (RMD).

MATERIALS AND METHODS

This is a retrospective bi-center cohort study. Based on cardiac CT, mitral valve calcification and mitral structure in RMD were quantified and evaluated. The primary outcome was EGMR. A logical regression algorithm was applied to the scoring model.

RESULTS

A total of 579 patients were enrolled in our study from January 1, 2019, to August 31, 2022. Of these, 443 had baseline cardiac CT scans of adequate quality. The calcification quality score, calcification and thinnest part of the anterior leaflet clean zone, and papillary muscle symmetry were the independent CT factors of EGMR. Coronary artery disease and pulmonary artery pressure were the independent clinical factors of EGMR. Based on the above six factors, a scoring model was established. Sensitivity = 95% and specificity = 95% were presented with a cutoff value of 0.85 and 0.30 respectively. The area under the receiver operating characteristic of external validation set was 0.84 (95% confidence interval [CI] 0.73-0.93).

CONCLUSIONS

Mitral valve repair is recommended when the scoring model value > 0.85 and mitral valve replacement is prior when the scoring model value < 0.30. This model could assist in guiding surgical strategies for RMD.

CLINICAL RELEVANCE STATEMENT

The model established in this study can serve as a reference indicator for surgical repair in rheumatic mitral valve disease.

KEY POINTS

• Cardiac CT can reflect the mitral structure in detail, especially for valve calcification. • A model based on cardiac CT and clinical factors for predicting early good mitral valve repair was established. • The developed model can help cardiac surgeons formulate appropriate surgical strategies.

Mitral regurgitation carries greater prognostic significance than mitral stenosis in patients undergoing transcatheter aortic valve replacement

AIMS

This study assessed the outcomes of concomitant mitral valve disease and severe aortic stenosis in patients undergoing transcatheter aortic valve replacement (TAVR).

METHODS

Echocardiographic data of 813 patients with severe aortic stenosis undergoing transfemoral TAVR were collected, and clinical outcomes were analyzed for individuals with mitral stenosis and mitral regurgitation.

RESULTS

The final cohort includes 788 patients with severe calcific aortic stenosis. Among single parameters of mitral stenosis, a smaller baseline mitral valve area (MVA) by the continuity equation and higher postprocedural mean mitral gradients (MMG) were associated with an increased risk of death at 1 year (P-values 0.02 and <0.01, respectively), but no correlation with outcomes was demonstrated after multivariate adjustment for major prognosticators. Mitral stenosis (based on MVA + MMG) was not associated with complications or mortality. Mitral regurgitation was present in 94.6% of the population at baseline and regressed by at least one grade post-TAVR in 28% of the patients. The improvement in mitral regurgitation was associated with a greater prosthetic effective orifice area (P-value 0.03). Significant (at least moderate) residual mitral regurgitation was correlated with short-term complications and shown to be an independent predictor of 1-year mortality (P-value 0.02, odds ratio (OR) 5.37, confidence interval 1.34-21.5).

CONCLUSION

Mitral regurgitation has a greater impact on TAVR patients than mitral stenosis as assessed by functional methods.

Effect of temporal resolution on calcium scoring: insights from photon-counting detector CT

To intra-individually investigate the variation of coronary artery calcium (CAC), aortic valve calcium (AVC), and mitral annular calcium (MAC) scores and the presence of blur artifacts as a function of temporal resolution in patients undergoing non-contrast cardiac CT on a dual-source photon counting detector (PCD) CT. This retrospective, IRB-approved study included 70 patients (30 women, 40 men, mean age 78 ± 9 years) who underwent ECG-gated cardiac non-contrast CT with PCD-CT (gantry rotation time 0.25 s) prior to transcatheter aortic valve replacement. Each scan was reconstructed at a temporal resolution of 66 ms using the dual-source information and at 125 ms using the single-source information. Average heart rate and heart rate variability were calculated from the recorded ECG. CAC, AVC, and MAC were quantified according to the Agatston method on images with both temporal resolutions. Two readers assessed blur artifacts using a 4-point visual grading scale. The influence of average heart rate and heart rate variability on calcium quantification and blur artifacts of the respective structures were analyzed by linear regression analysis. Mean heart rate and heart rate variability during data acquisition were 76 ± 17 beats per minute (bpm) and 4 ± 6 bpm, respectively. CAC scores were smaller on 66 ms (median, 511; interquartile range, 220-978) than on 125 ms reconstructions (538; 203-1050, p < 0.001). Median AVC scores [2809 (2009-3952) versus 3177 (2158-4273)] and median MAC scores [226 (0-1284) versus 251 (0-1574)] were also significantly smaller on 66ms than on 125ms reconstructions (p < 0.001). Reclassification of CAC and AVC risk categories occurred in 4% and 11% of cases, respectively, whereby the risk category was always overestimated on 125ms reconstructions. Image blur artifacts were significantly less on 66ms as opposed to 125 ms reconstructions (p < 0.001). Intra-individual analyses indicate that temporal resolution significantly impacts on calcium scoring with cardiac CT, with CAC, MAC, and AVC being overestimated at lower temporal resolution because of increased motion artifacts eventually leading to an overestimation of patient risk.

Calcium score of the entire thoracic aorta is an independent predictor of all-cause mortality in patients referred to chest computed tomography

BACKGROUND

Thoracic arterial calcifications (TAC) are not routinely reported or quantified in chest CT scans. We aimed to evaluate the association between TAC of the entire thoracic aorta and all-cause mortality (ACM) in patients referred to standard chest CT.

METHODS

A retrospective analysis of consecutive standard chest CT scans (non-gated, non-contrast) for the quantification of TAC, CAC and aortic valve calcification. TAC was divided into 4 sample-derived categories (TAC 1 = 0, TAC 2 = 1-65, TAC 3 = 66-439 and TAC 4 ≥ 440). Data regarding ACM was retrieved from the health care provider database. Multivariate Cox proportional regression models were used to assess associations between the TAC categories and ACM.

RESULTS

The study cohort included 415 patients (mean age 67 years, 52% male); 107 ACM events were recorded during a median follow-up of 9 years (inter-quartile range: 7.4-10.4). The rate of ACM was 13%, 25%, 32%, 41% according to TAC category (p < 0.001). The highest TAC category (≥ 440) was a strong and independent predictor of ACM [HR = 1.69 (1.13-2.52; 0.01)] in multivariate analysis. Other independent predictors of ACM included age [HR = 1.07 (1.04-1.10; p < 0.001)], male sex [HR = 2.27 (1.49-3.46; 0.001)] and malignancy [HR = 2.21 (1.49-3.23; < 0.001)].

CONCLUSIONS

Severe TAC (≥ 440) was found to be an independent predictor of ACM. Thus, we suggest that documenting and quantifying TAC should be routinely incorporated into standard chest CT reports.

Noncontrast cardiac computed tomography-derived mitral annular calcification scores in mitral valve disease

BACKGROUND AND AIMS

Mitral annular calcification (MAC) by computed tomography (CT) is reported as an independent predictor of poor outcomes. However, it currently remains unclear if quantitative MAC parameters provide more value for mitral valve disease (MVD) management, therefore, we examined the prognostic value of MAC scores using noncontrast cardiac-CT in MVD patients.

METHODS

Between January 2020 and December 2021, we prospectively enrolled 300 consecutive patients with MVD (MAC-present = 80 and MAC-absent = 220) undergoing preoperative cardiac-CT and mitral valve (MV) surgery. Noncontrast cardiac-CT images were used to qualitatively detect MAC (present or absent) and evaluate MAC scores. For analyses, we also collected baseline clinical data, intraoperative conversion (from MV repair to MV replacement), and follow-up arrhythmia data.

RESULTS

Compared with the MAC-absent group, MAC-present patients were older (62 ± 7 vs. 58 ± 9 years, p < .001), mostly women (55% vs. 39.5%, p = .017), and also had aortic valve calcification (57.5% vs. 23.2%, p < .001), mitral stenosis (82.5% vs. 61.8%, p < .001), atrial fibrillation (30% vs. 11.8%, p < .001), and larger left atrial end-diastolic dimension (LADD, 49 [44-56] versus 46 [41-50], p = .001]. Furthermore, MAC-present patients underwent more MV replacements (61.8% vs. 82.5%, p = .001) and experienced a higher intraoperative conversion prevalence (11.8% vs. 61.3%, p < .001). Multiple logistic regression analyses showed that the female gender (odds ratio [OR]/95% confidence interval [CI]/p = 2.001/1.042-3.841/0.037) and MAC scores (OR/95% CI/p = 10.153/4.434-23.253/p < .001) were independent predictors of intraoperative conversion. During a follow-up of 263 ± 134 days, MAC-present patients had more arrhythmias (42.5% vs. 9.5%, p < .001). Also, MAC-scores (hazard ratio [HR]/95% CI/p = 6.841/3.322-14.089/p < .001) and LADD (HR/95% CI/p = 1.039/1.018-1.060/p < .001) were independently associated with arrhythmias by Cox regression analyses.

CONCLUSIONS

Noncontrast cardiac CT-derived MAC-scores showed a high risk for intraoperative conversion and follow-up arrhythmias in MVD-patients.

Cardiac Virtual Noncontrast Images for Calcium Quantification with Photon-counting Detector CT

Purpose

To assess the accuracy of aortic valve calcium (AVC), mitral annular calcium (MAC), and coronary artery calcium (CAC) quantification and risk stratification using virtual noncontrast (VNC) images from late enhancement photon-counting detector CT as compared with true noncontrast images.

Materials and Methods

This retrospective, institutional review board-approved study evaluated patients undergoing photon-counting detector CT between January and September 2022. VNC images were reconstructed from late enhancement cardiac scans at 60, 70, 80, and 90 keV using quantum iterative reconstruction (QIR) strengths of 2-4. AVC, MAC, and CAC were quantified on VNC images and compared with quantification of AVC, MAC, and CAC on true noncontrast images using Bland-Altman analyses, regression models, intraclass correlation coefficients (ICC), and Wilcoxon tests. Agreement between severe aortic stenosis likelihood categories and CAC risk categories determined from VNC and true noncontrast images was assessed by weighted κ analysis.

Results

Ninety patients were included (mean age, 80 years ± 8 [SD]; 49 male patients). Scores were similar on true noncontrast images and VNC images at 80 keV for AVC and MAC, regardless of QIR strengths, and VNC images at 70 keV with QIR 4 for CAC (all P > .05). The best results were achieved using VNC images at 80 keV with QIR 4 for AVC (mean difference, 3; ICC = 0.992; r = 0.98) and MAC (mean difference, 6; ICC = 0.998; r = 0.99), and VNC images at 70 keV with QIR 4 for CAC (mean difference, 28; ICC = 0.996; r = 0.99). Agreement between calcification categories was excellent on VNC images at 80 keV for AVC (κ = 0.974) and on VNC images at 70 keV for CAC (κ = 0.967).

Conclusion

VNC images from cardiac photon-counting detector CT enables patient risk stratification and accurate quantification of AVC, MAC, and CAC.Keywords: Coronary Arteries, Aortic Valve, Mitral Valve, Aortic Stenosis, Calcifications, Photon-counting Detector CT Supplemental material is available for this article © RSNA, 2023.

Mitral Valve Replacement for Mitral Stenosis Secondary to Massive Mitral Annular Calcium

Mitral annular calcium (MAC) may produce mitral stenosis (MS) if its quantity is massive. We define massive MAC as the presence of a huge quantity of calcium underlying the posterior mitral leaflet and extending across all or nearly all of the ventricular aspect of the anterior mitral leaflet. This report was prompted to emphasize the hazards of performing mitral valve replacement in patients with MS secondary to massive MAC. The clinical data and morphology of the operatively excised mitral valves from the 11 patients who had mitral valve replacement for MS secondary to massive MAC are described. Of the 11 patients, 6 died postoperatively, 5 of whom had 4+/4+ MAC. The high mortality in these patients suggests that the decision to perform mitral valve replacement needs to be carefully considered if the quantity of MAC is massive.

Increased whole blood viscosity is associated with primary idiopathic complete atrioventricular block and poor clinical outcomes in these patients

BACKGROUND

Complete atrioventricular block is most commonly caused by age-related degeneration and fibrosis in the cardiac conduction system and is called primary idiopathic complete atrioventricular (iCAVB). Although many factors affect this situation, which increases with age in the cardiac conduction system, the relationship between whole blood viscosity (WBV) and iCAVB has not been clarified until now. In this study, we aim to reveal the relationship between iCAVB and WBV.

METHODS AND RESULTS

141 patients with dual-chamber permanent pacemaker implanted for iCAVB and 140 age- and sex-matched subjects were included in this study. The WBV values of the study groups were compared in both high shear rate (HSR) and low shear rate (LSR). Both WBV at HSR and WBV at LSR were significantly higher in the iCAVB group compared to the control group (16.11 [15.14-16.89] vs 14.40 [13.62-15.58]; 39.82 [17.43-55.23] vs 1.38 [-13.14-26.73]; p < 0.001, respectively). The patient population was followed up for an median of 38 months for all-cause mortality. Higher mortality rates were found in higher WBV at HSR and WBV at LSR (p < 0.001,for both).

CONCLUSIONS

In this study, WBV was found to be an independent predictor for iCAVB, and in these patients WBV was associated with poor clinical outcomes.

Mitral annular calcification and valvular dysfunction: multimodality imaging evaluation, grading, and management

Mitral annular calcification (MAC) refers to calcium deposition in the fibrous skeleton of the mitral valve. It has many cardiovascular associations, including mitral valve dysfunction, elevated cardiovascular risk, arrhythmias, and endocarditis. Echocardiography conventionally is the first-line imaging modality for anatomic assessment, and evaluation of mitral valve function. Cardiac computed tomography (CT) has demonstrated importance as an imaging modality for the evaluation and planning of related procedures. It also holds promise in quantitative grading of MAC. Currently, there is no universally accepted definition or classification system of MAC severity. We review the multimodality imaging evaluation of MAC and associated valvular dysfunction and propose a novel classification system based on qualitative and quantitative measurements derived from echocardiography and cardiac CT.

Current Status and Future Prospects of Transcatheter Mitral Valve Replacement: JACC State-of-the-Art Review

Mitral regurgitation (MR) is the most prevalent valvular heart disease and, when left untreated, it confers a poorer prognosis. Catheter-based repair therapies face some limitations like their applicability on challenging anatomies and the potential recurrence of significant MR over time. Transcatheter mitral valve replacement (TMVR) has emerged as a less invasive approach potentially overcoming some of the current limitations associated with transcatheter mitral valve repair. Several devices are under clinical investigation, and a growing number of systems allow for a fully percutaneous transfemoral approach. In this review, the authors aimed to delineate the main challenges faced by the TMVR field, to highlight the key aspects for procedural planning, and to describe the clinical results of the TMVR systems under clinical investigation. Finally, they also discuss what the future perspectives are for this emerging field.

Clinical impact of mitral calcium volume in patients undergoing transcatheter aortic valve implantation

BACKGROUND

Mitral annular calcification (MAC) has been associated with mitral valve (MV) disease and cardiovascular events in patients undergoing transcatheter aortic valve implantation (TAVI). We aimed to investigate the incidence and impact of mitral calcium volume (MCV) quantified by multidetector computed tomography (MDCT) on MV function and clinical outcomes after TAVI.

METHODS

Consecutive patients with exploitable echocardiography and MDCT performed during TAVI screening were enrolled in this retrospective analysis. Mitral calcium was assessed visually and measured using a semi-automatic tool developed for the aortic valve in an off-label fashion.

RESULTS

MCV >0 mm³ was found in 65% of the 875 included patients. Patients with calcification were older (82 ± 6 versus 81 ± 7; P = 0.002) and had high prevalence of renal dysfunction (69% versus 61%; P = 0.017) and mitral stenosis (25% versus 4%, P < 0.001). MCV correlated well with visual MAC severity (r = 0.94; P < 0.001), but showed a greater predictive value for mitral stenosis (AUC = 0.804 vs. 0.780, P = 0.012) , while it was not a predictor of mitral regurgitation (AUC = 0.514). Correlations were found between MCV and echocardiographic parameters including MV area, mean transmitral gradient, and pressure half-time (P < 0.001 for all). MCV did not impact on cardiovascular mortality or new permanent pacemaker implantation after TAVI.

CONCLUSIONS

Calcification of the mitral apparatus is common in TAVI candidates and results in mitral stenosis in 25% of the patients. Increasing MCV predicts mitral stenosis, but had no impact on clinical outcomes following TAVI.

CLINICAL TRIAL REGISTRATION

NCT01368250.

[Transcatheter aortic valve implantation and conduction disturbances]

Transcatheter aortic valve implantation (TAVI) is currently becoming the treatment of choice for patients with calcific aortic stenosis. Despite several technical improvements, the incidence of conduction disturbances has not diminished and remains TAVI's major complication. These disturbances include the occurrence of left bundle branch block and/or high-grade atrioventricular block often requiring pacemaker implantation. The proximity of the aortic valve to the conduction system (conduction pathways) accounts for the occurrence of these complications. Several factors have been identified as carrying a high risk of conduction disturbances like the presence of pre-existing right bundle branch block, the type of valve implanted, the volume of aortic and mitral calcifications, the size of the annulus and the depth of valve implantation. Left bundle branch block is the most frequent post TAVI conduction disturbance. Whereas the therapeutic strategy for persistent complete atrioventricular block is simple, it becomes complex in the presence of fluctuating changes in PR interval and left bundle branch block duration. The QRS width threshold value (150-160 ms) indicative of the need for pacemaker implantation is still being debated. Although there are currently no recommendations regarding the management of these conduction disturbances, the extension of TAVI indications to patient at low surgical risk calls for a standardization of our practice. However, a decision algorithm was recently proposed by a group of experts composed of interventional cardiologists, electrophysiologists and cardiac surgeons. There are still uncertainties about the appropriate timing of pacemaker implantation and the management of new onset left bundle branch block.