Global longitudinal strain: is it a superior assessment method for left ventricular function in patients with chronic mitral regurgitation undergoing mitral valve replacement?

Does high dose statin pretreatment affect global strains in patients undergoing valve replacement

Purpose

To study the effect of rosuvastatin 40 mg (initiated 7 days prior to surgery) in patients undergoing valve replacement (VR) for rheumatic mitral valve disease on left ventricular (LV) strain and biomarker release kinetics.

Methods

In this randomized study, cardiac biomarkers viz. troponin I (TnI), Creatine kinase MB (CK-MB), N-terminal pro B-type natriuretic peptide (NTPBNP) were measured before surgery; and 8, 24 and 48 h postoperatively. Global LV (circumferential, global circumferential strain (GCS); longitudinal, GLS; radial, global radial strain (GRS)) strains were measured preoperatively; and 48 h and 30 days postoperatively.

Results

Following VR, Global Longitudinal Strain (GLS), Global Circumferential Strain (GCS) and Global Radial Strain (GRS) declined at 48 h in both statin loaded (SL) and non loaded (NL) groups. The %decline in strain was significantly lower in SL group (% change in GLS 35.8% vs 38.8%, GCS 34% vs 44.1%, GRS 45.7% vs 52.6%; p < 0.001).All strain values improved at 30 days with higher improvement in SL group (GLS -15.92 ± 2.00% vs -12.6 ± 1.66%, GCS -15.12 ± 2.93% vs -13.04 ± 2.44%; GRS 22.12 ± 6.85% vs 19.32 ± 6.48%). While TnI, CKMB, NTPBNP increased following surgery, values at 8, 24 and 48 h were lower in the SL vs. NL group. Mean change (baseline to peak biomarker value) was also significantly lower in SL group.The SL group had shorter hospital and Intensive Care Unit (ICU) stay. On Receiver Operating Characteristic Curve (ROC) analysis, baseline GCS ≤ 14% best predicted postoperative 30 day Left Ventricular Ejection Fraction (LVEF) ≤ 50%.

Conclusion

Pre-operative high dose rosuvastatin was "cardioprotective" with favorable effect on LV global strain and release kinetics of biomarkers. These cut-offs (described for the first time for rheumatic VR) can be used as prognostic predictors.

Speckle tracking echocardiography in primary mitral regurgitation: should we reconsider the time for intervention?

Thanks to the improvement in mitral regurgitation (MR) diagnostic and therapeutic management, with the introduction of minimally invasive techniques which have considerably reduced the individual surgical risk, the optimization of the timing for MR “open” or percutaneous surgical treatment has become a main concern which has highly raised scientific interest. In fact, the current indications for intervention in MR, especially in asymptomatic patients, rely on echocardiographic criteria with high severity cut-offs that are fulfilled only when not only mitral valve apparatus but also the cardiac chambers’ structure and function are severely impaired, which results in poor benefits for post-operative clinical outcome. This led to the need of new indices to redefine the optimal surgical timing in these patients. Speckle tracking echocardiography provides early markers of cardiac dysfunction due to subtle myocardial impairment; therefore, it could offer pivotal information in this setting. In fact, left ventricular and left atrial strains have already shown evidence about their usefulness in recognizing MR impact not only on symptoms and quality of life but also on cardiovascular events and new-onset atrial fibrillation in these patients. Moreover, right ventricular strain could be used to identify those patients with advanced cardiac damage and different grades of right ventricular dysfunction, which entails higher risks for cardiac surgery that could overweigh surgical benefits. This review aims to describe the importance of reconsidering the timing of intervention in MR and to analyze the potential additive value of speckle tracking echocardiography in this clinical setting.

Global longitudinal strain to determine optimal timing for surgery in primary mitral regurgitation: A systematic review

BACKGROUND

Primary mitral regurgitation (PMR) results in adverse remodeling changes and left ventricular (LV) dysfunction. Assessing LV function has prognostic value in predicting morbidity and mortality. Indications for surgery include parameters such as LV ejection fraction (LVEF) and systolic dimensions. Current guidelines are limited in identifying patients at optimal time for surgery. Impaired postoperative LVEF indicates poor prognostic outcomes and subsequent heart failure. Global longitudinal strain (GLS) via speckle tracking echocardiography (STE) presents as a promising parameter to detect subclinical dysfunction in asymptomatic patients.

METHODS

Following PRISMA guidelines, a literature search was conducted with Cochrane Library, PudMed, SCOPUS, and Web of Science. Key MeSH terms included "mitral regurgitation," "mitral valve insufficiency," "global longitudinal strain," "deformation," "LV-GLS," and "GLS." Inclusion criteria included (1) patients with severe PMR, (2) mixed population of symptomatic and asymptomatic patients, (3) standardized methods in assessing LV systolic function using 2D-STE, (4) valve repair or replacement surgery, and (5) patient outcomes measured after surgery. Search returned 234 papers, 12 of which met the inclusion criteria and were subsequently reviewed.

RESULTS

Baseline GLS is an independent predictor of postoperative outcomes, ranging from -17.9 to -21.7% GLS. A significant negative correlation was observed between preoperative GLS and postoperative LVEF. Impaired baseline GLS was associated with higher mortality rates. Better long-term survival rates were seen in patients who underwent early surgery.

CONCLUSION

GLS shows sensitivity in predicting long-term postoperative outcomes. Further analysis is required to determine preoperative GLS threshold to identify asymptomatic patients at the optimal time for mitral valve surgery.