Should pre-operative left atrial volume receive more consideration in patients with degenerative mitral valve disease undergoing mitral valve surgery?

Stage-based approach to predict left ventricular reverse remodeling after mitral repair

Background

Although predictors of reverse left ventricular (LV) remodeling postmitral valve repair are critical for guiding perioperative decision‐making, there remains a paucity of randomized, prospective data to support the criteria that potential predictor variables must meet.

Methods and Results

The CAMRA CardioLink‐2 randomized trial allocated 104 patients to either leaflet resection or preservation strategies for mitral repair. The correlation of indexed left ventricular end‐systolic volume (LVESVI), indexed left ventricular end‐diastolic volume (LVEDVI), and left ventricular ejection fraction (LVEF) were tested with univariate analysis and subsequently with multivariate analysis to determine independent predictors of reverse remodeling at discharge and at 12 months postoperatively. At discharge, both LVESVI and LVEDVI were independently associated with their preoperative values (p < .001 for both) and LVEF by preoperative LVESVI (p < .001). Mitral ring size was favorably associated with the change in LVESVI (p < .05) and LVEF (p < .01) from predischarge to 12 months, while the mean mitral valve gradient after repair was adversely associated with the change in LVESVI (p < .05) and LVEDVI (p < .05). No significant associations were found between reverse remodeling and coaptation height nor mitral repair technique.

Conclusions

Beyond confirming the lack of impact of mitral repair technique on reverse remodeling, this investigation suggests that recommending surgery before significant LV dilatation or dysfunction, as well as higher postoperative mitral valve hemodynamic performance, may enhance remodeling capacity following mitral repair.

Left Atrial Remodeling and Dysfunction in Swine Models of Mitral Regurgitation

BACKGROUND

Left atrial (LA) dysfunction is one of the predictive factors of worse outcomes after mitral valve surgery for mitral regurgitation (MR). We aimed to investigate the effect of MR etiology on progression of LA remodeling in swine MR models.

METHODS

MR was induced in 14 Yorkshire pigs using catheter-based procedures. Seven pigs underwent simultaneous occlusions of the left circumflex artery and the diagonal branch, which resulted in ischemic MR (IMR group). The other seven pigs underwent chordal severing to induce leaflet prolapse simulating degenerative MR (DMR group). Changes in LA volume and function were assessed at baseline, 1 and 3 months using echocardiography and hemodynamic evaluations. Histopathological assessments were conducted to evaluate LA hypertrophy and fibrosis.

RESULTS

At 3 months, quantitative MR severity was comparable and severe in both groups. Despite the similar degree of MR, minimum LA volume index increased significantly more in the IMR group (IMR: 11.9±6.4 to 73.2±6.4, DMR: 10.7±6.4 to 29.5±6.4 ml/m², p_interaction=0.004). Meanwhile, increase in maximum LA volume index was similar between the groups, resulting in lower LA emptying function in the IMR group (IMR: 60.1±3.1 to 29.4±3.1, DMR: 62.4±3.1 to 58.2±3.1%, p_interaction=0.0003). LA reservoir strain assessed by echocardiography was also significantly lower in the IMR group. Histological analyses revealed increased LA cellular hypertrophy and fibrosis in the IMR group.

CONCLUSIONS

Ischemic MR is associated with aggressive remodeling and reduced emptying function compared to MR due to leaflet prolapse. Earlier intervention might be necessary for ischemic MR to prevent LA remodeling.

Utility of Functional and Volumetric Left Atrial Parameters Derived From Preprocedural Cardiac CTA in Predicting Mortality After Transcatheter Aortic Valve Replacement

Background: Cardiac CTA is required for preprocedural workup before transcatheter aortic valve replacement (TAVR) and can be used to assess functional parameters of the left atrium (LA). Objective: We aimed to evaluate the utility of functional and volumetric LA parameters derived from cardiac CTA to predict mortality in patients with severe aortic stenosis (AS) undergoing TAVR. Methods: This retrospective study included 175 patients with severe AS (median age 79 years; 92 male, 83 female) who underwent cardiac CTA for clinical pre-TAVR assessment. A postdoctoral research fellow calculated maximum and minimum LA volumes using biplane area-length measurements; the values were indexed to body surface area (LAVImax and LAVImin, respectively). LA emptying fraction (LAEF) was automatically calculated. All-cause mortality within a 24-month follow-up period post-TAVR was recorded. To identify parameters predictive of mortality, Cox regression was performed, and results were summarized by hazard ratio (HR) and 95% CI. Harrell's c-index was used to assess model performance. A radiology resident repeated the measurements in a random sample of 20% (n=35) of cases, and interobserver agreement was computed using the intraclass correlation coefficient (ICC). Results: Thirty-eight deaths (22%) were recorded within a median follow-up of 21 months. LAVImax (HR 1.02 [1.01-1.04]; p=.005), LAVImin (HR 1.02 [1.01-1.04]; p<.001), and LAEF (HR 0.97 [0.95-0.99]; p=.002) were predictive of mortality in univariable analysis. After adjusting for clinical parameters, only LAEF (HR 0.97 [0.94-0.99]; p=.02) independently predicted mortality. The c-index of the Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) significantly increased from 0.64 to 0.68, 0.69, and 0.70 when incorporating into the model LAVImax, LAVImin, and LAEF, respectively. ICC for maximum and minimum LA volumes and LAEF ranged from 0.94 to 0.99. Conclusion: LAEF derived from preprocedural cardiac CTA independently predicts mortality in patients with severe AS undergoing TAVR. Clinical impact: Cardiac CTA-derived LA function, evaluated during pre-TAVR workup, can be used to assess preprocedural risk and may improve risk stratification in post-TAVR surveillance.

Echocardiographic and clinical outcome after mitral valve plasty with a minimal access or conventional sternotomy approach

BACKGROUND

The aim of this study is to evaluate the effects of minimal access mitral valve surgery (MAMVS) versus conventional surgery with or without concomitant tricuspid valve plasty (TVP) in consecutive patients with mitral regurgitation (MR) on clinical and echocardiographic outcome.

METHODS

One-hundred-and-twenty patients operated for MR (91 conventional and 29 MAMVS) were followed by echocardiography and quality of life assessment before and 6 months after surgery.

RESULTS

Patients in the MAMVS group were younger, more often in NYHA functional class I-II and had lower NT-proBNP levels. Only four patients (all in the conventional group) underwent mitral valve replacement. There were no significant differences in complications between MAMVS and conventional surgery. At 6 months, comparable MR reduction and left ventricular remodeling data were seen, left atrial remodeling was most prominent in the MAMVS group, 71 [55-90] to 43 [35-58] versus 69 [53-89] to 49 [41-70] mL/m² in the conventional group (P<0.05). Significant improvement for all quality of life domains were seen, except for pain, with no intergroup differences. Twenty-seven (23%) patients underwent concomitant TVP, all in the conventional group. Tricuspid regurgitation decreased after concomitant TVP (P<0.001), whereas in patients with no TVP no significant changes occurred. At 6 months tricuspid regurgitation grade was comparable in patients with TVP versus patients without need for TVP.

CONCLUSIONS

MR severity reduced significantly, with no difference between conventional surgery and MAMVS in reducing MR, with superior left atrial remodeling in the MAMVS group. In-hospital complications and NYHA class and quality of life assessment were not different between conventional surgery and MAMVS.

Higher preoperative left atrial volume index predicts lack of mitral regurgitation improvement after transcatheter aortic valve replacement

BACKGROUND

Moderate-to-severe mitral regurgitation is present in 20-35% of patients undergoing transcatheter aortic valve replacement (TAVR) and the current literature lacks simple echocardiographic parameters, which can predict post-TAVR changes in mitral regurgitation. The aim of this study is to investigate the echocardiographic predictors of improvement or worsening of mitral regurgitation in patients undergoing TAVR with moderate-to-severe mitral regurgitation.

METHODS

This retrospective study included 113 patients who underwent TAVR with preoperative mitral regurgitation grade at least 2. Patients with concomitant coronary artery disease requiring treatment were excluded. Mitral regurgitation was related to the annular dilatation or tethering mechanism in all patients. Preoperative and postoperative echocardiographies were compared in terms of mitral regurgitation and other commonly measured parameters.

RESULTS

After TAVR, a reduction in mitral regurgitation was observed in 62.8% of cases. On the basis of the difference between postoperative and preoperative echocardiograms, 71 patients had improved mitral regurgitation, whereas 42 patients had stable or worsened mitral regurgitation. After analyzing preoperative echocardiographic parameters with regard to this group difference, left atrial volume index (LAVI) was the only variable that was different between groups (33.4 ± 4.8 ml/m in improved mitral regurgitation vs. 39.8 ± 3.0 ml/m in not improved mitral regurgitation, P < 0.001). In a multivariable logistic regression model, a LAVI increase was associated with lack of an acute reduction in mitral regurgitation (odds ratio = 1.41, P < 0.001) after adjustment for age and preoperative serum creatinine.

CONCLUSION

Higher preoperative LAVI is a determinant predictor of lack of an acute reduction in mitral regurgitation after TAVR, and LAVI could be used as a stratifying tool to tailor the treatment strategy and the timing of the procedures. However, validation of these results and long-term outcomes are warranted to support those conclusions.

Clinical Risk Factors for Postoperative Atrial Fibrillation among Patients after Cardiac Surgery

BACKGROUND

Postoperative atrial fibrillation (POAF) is a common arrhythmia following cardiac surgery and is associated with increased health-care costs, complications, and mortality. The etiology of POAF is incompletely understood and its prediction remains suboptimal. Using data from published studies, we performed a systemic review and meta-analysis to identify preoperative clinical risk factors associated with patients at increased risk of POAF.

METHODS

A systematic search of PubMed, MEDLINE, and EMBASE databases was performed.

RESULTS

Twenty-four studies that reported univariate analysis results regarding POAF risk factors, published from 2001 to May 2017, were included in this meta-analysis with a total number of 36,834 subjects. Eighteen studies were performed in the United States and Europe and 16 studies were prospective cohort studies. The standardized mean difference (SMD) between POAF and non-POAF groups was significantly different (reported as [SMD: 95% confidence interval, CI]) for age (0.55: 0.47-0.63), left atrial diameter (0.45: 0.15-0.75), and left ventricular ejection fraction (0.30: 0.14-0.47). The pooled odds ratios (ORs) (reported as [OR: 95% CI]) demonstrated that heart failure (1.56: 1.31-1.96), chronic obstructive pulmonary disease (1.36: 1.13-1.64), hypertension (1.29: 1.12-1.48), and myocardial infarction (1.18: 1.05-1.34) were significant predictors of POAF incidence, while diabetes was marginally significant (1.06: 1.00-1.13).

CONCLUSION

The present analysis suggested that older age and history of heart failure were significant risk factors for POAF consistently whether the included studies were prospective or retrospective datasets.