Assessment of the left atrial volume and function following percutaneous mitral balloon valvuloplasty: Insights into acute and late impact of atrial fibrillation on atrial remodeling

BACKGROUND

Rheumatic mitral stenosis (MS) leads to LA remodeling with disordered electrical activation that may revert with valve intervention. This study aimed to assess the acute and late impact of percutaneous mitral balloon valvuloplasty (PMBV) on LA volume and function in patients with atrial fibrillation (AF) compared with sinus rhythm.

METHODS

A total of 167 patients with severe MS undergoing PMBV were prospectively enrolled. LA volumes and function were measured by three-dimensional echocardiography (3DE) pre PMBV, within 24 to 48 h after PMBV, and at 1 year.

RESULTS

Mean age was 43.5 ± 11.8 years old, and 142 (85%) patients were women. At baseline, 46 patients (27.5%) were in permanent AF, and 62 (37.1%) classified as New York Heart Association functional class III or IV. In sinus rhythm population, LA volumes decreased immediately after PMBV and continue to decrease at 1-year follow-up. LA emptying fraction increased from 23.6 ± 10.4% to 33.8 ± 11.9% acutely after the procedure (p < 0.001), and to 37.2 ± 13.2% at 1-year follow-up (p = 0.028). Patients with AF only had a significant decrease in LA minimum volume immediately after PMBV, with no significant changes in maximum volume either immediately or at follow-up. In these patients, LA emptying fraction increased immediately after the procedure from 15.8 ± 9.9% to 22.8 ± 9.8 (p = 0.001) with no evidence for additional improvement at the 1-year follow-up. Age, and post-procedural mean gradient were identified as the most significant factors associated with the absolute changes in LA function between baseline and the 1-year follow-up.

CONCLUSIONS

In patients with severe MS, the impact of PMBV on LA volume and function varies according to cardiac rhythm. In patients in sinus rhythm, the procedure leads to improvement of LA volumes and function both acutely and at 1-year follow-up. Patients with AF had a lesser improvement in LA function immediately after the procedure, without further improvement over time despite adequate relief of valve obstruction.

Pulmonary artery pressure response to percutaneous mitral valvuloplasty: Associated factors and clinical implications

BACKGROUND

Pulmonary hypertension (PH) is a marker of poor outcome in mitral stenosis (MS), which improves after percutaneous mitral valvuloplasty (PMV). However, mechanical interventions for relief of valve obstruction often but not always reduce pulmonary pressures. This study aimed to assess the parameters associated with abnormal pulmonary artery pressure (PAP) response immediately after a successful PMV, and also its impact on long-term outcome.

METHODS

A total of 181 patients undergoing PMV for rheumatic MS were prospectively enrolled. Invasive hemodynamic and echocardiographic measures were examined in all patients. Abnormal PAP response was defined as the mean PAP (mPAP) values unchanged at the end of the procedure. Long-term outcome was a composite endpoint of death, mitral valve replacement, repeat PMV, new onset of atrial fibrillation (AF), or stroke.

RESULTS

The mean age was 44.1 ± 12.6 years, and 157 patients were women (86.7%). In the overall population, mPAP decreased from 33.4 ± 13.1 mmHg pre to 27.6 ± 9.8 mmHg post (p < 0.001). Following PMV, 52 patients (28.7%) did not have any reduction of mPAP immediately after the PMV. Multivariable analysis adjusting for baseline values of PAP and mitral valve area revealed that AF (Odds ratio [OR] 2.7, 95% [confidence interval] CI 1.3 to 6.7), maximum mitral valve leaflets displacement (OR 0.8, 95% CI 0.7 to 0.9), and post-procedural left ventricular compliance (OR 0.7, 95% CI 0.5 to 0.9) were predictors of a lack of improvement in mPAP. During a median follow-up of 4.4 years, the endpoint was reached in 56 patients (31%). The pulmonary pressure response to PMV was not an independent predictor of long-term events.

CONCLUSIONS

In patients with MS undergoing PMV, pulmonary pressures may not reduce immediately after the procedure, despite adequate opening of the valve. Abnormal PAP response can be predicted from baseline clinical and valvular characteristics as well as post-procedural left ventricular compliance. The lack of any immediate reduction in mPAP is not associated with long-term adverse outcomes.

The Importance of Conscious Sedation for Life-Saving Valve Procedures in Patients With Rheumatic Heart Disease From Low- to Middle-Income Countries

BACKGROUND

Severe valve disease, which requires intervention, remains strongly associated with mortality in patients with rheumatic heart disease. Percutaneous mitral commissurotomy (PMC) is the procedure of choice for the treatment of patients with isolated or predominantly rheumatic mitral stenosis. This procedure has been performed under sedation to avoid the potential effects of general anesthesia on intracardiac pressure measurements. However, there are limited data on sedation during PMC, especially using easily available medications in low- and middle-income countries.

OBJECTIVES

This study was designed to evaluate the efficacy and hemodynamic effects of conscious sedation during PMC in patients with significant mitral stenosis.

METHODS

This study prospectively enrolled 23 patients who underwent PMC with the Inoue balloon technique for hemodynamically significant mitral stenosis. For conscious sedation, midazolam 25 μg/kg and fentanyl 1 μg/kg were administered, and 5 min after the infusion, the level of sedation was evaluated by Ramsay sedation scale. A range of invasive hemodynamic measurements, including cardiac output and pulmonary artery pressures, were recorded before and immediately after sedation.

RESULTS

The mean age was 44.9 ± 10.8 years, and 19 patients (83%) were women. After sedation, the majority of patients were in categories 2 and 3 of the Ramsay sedation scale (cooperative, orientated, tranquil, and responding to commands). Oxygen saturation dropped from an average of 98.5% to 96.0% without supplementary oxygen. Left ventricular systolic pressure and central aortic pressures decreased after sedation. However, none of the other parameters changed significantly after sedation, including pulmonary artery pressures, pulmonary vascular resistance, and cardiac index.

CONCLUSIONS

This simple model of conscious sedation was able to promote anxiolysis, analgesia, and comfort for the procedure without serious hemodynamic effects, which can be a reasonable choice in developing countries.

Impact of left atrial compliance improvement on functional status after percutaneous mitral valvuloplasty

BACKGROUND

Conventional hemodynamic parameters may not accurately predict symptomatic improvement after percutaneous mitral valvuloplasty (PMV). Changes in left heart chamber compliance following adequate relief o0066 mitral stenosis (MS) may be useful in determining functional capacity after PMV. This study aims to determine the acute effects of PMV on compliance of the left heart and whether its changes relate to the patient's functional capacity.

METHODS

One-hundred thirty-seven patients with severe MS undergoing PMV were enrolled. Left atrial (C_a ) and left ventricular (C_v ) compliance were invasively estimated and net atrioventricular compliance (C_av ) was calculated before and immediately after the procedure. B-type natriuretic peptide (BNP) levels were obtained before and 24 hr after the procedure. The primary endpoint was functional status at 6-month follow-up, and the secondary endpoint was a composite of death, mitral valve (MV) replacement, repeat PMV, new onset of atrial fibrillation, or stroke in patients in whom PMV was successful.

RESULTS

The mean age was 43 ± 12 years, and 119 patients were female (87%). After PMV, C_a and C_av improved significantly from 5.3 [IQR 3.2-8.2] mL/mmHg to 8.7 [5.3-19.2] mL/mmHg (P < 0.001) and 2.2 [1.6-3.4] to 2.8 [2.1-4.1] mL/mmHg (P < 0.001), respectively, whereas C_v did not change (4.6 [3.2-6.8] to 4.4 [3.1-5.6]; P = 0.637). Plasma BNP levels significantly decreased after PMV, with no correlation between its variation and changes in left chamber compliance. At 6-month follow-up, NYHA functional class remained unchanged in 32 patients (23%). By multivariable analyses, changes in C_a immediately after PMV (adjusted OR 1.42; 95% CI 95% 1.02 to 1.97; P = 0.037) and younger age (adjusted OR 0.95; CI 95% 0.92-0.98; P = 0.004), predicted improvement in functional capacity at 6-month follow-up, independent of postprocedural data. The secondary endpoint were predicted by post-PMV mean gradient (adjusted HR 1.363; 95% CI 95% 1.027-1.809; P = 0.032), and lack of functional improvement at 6-month follow-up (adjusted HR 4.959; 95% 1.708-14.403; P = 0.003).

CONCLUSIONS

C_a and C_av increase significantly after PMV with no change in C_v . The improvement of C_a is an important predictor of functional status at 6-month follow up, independently of other hemodynamic data. Postprocedural mean gradient and lack of short-term symptomatic improvement were predictors of adverse outcome.

Impact of percutaneous mitral valvuloplasty on left ventricular function in patients with mitral stenosis assessed by 3D echocardiography

BACKGROUND

The status of intrinsic left ventricular (LV) contractility in patients with isolated rheumatic mitral stenosis (MS) has been debated. The acute changes in loading conditions after percutaneous mitral valvuloplasty (PMV) may affect LV performance. We aimed to examine the acute effects of PMV on LV function and identify factors associated with LV ejection fraction (LVEF) changes, and determinants of long-term events following the procedure.

METHODS

One hundred and forty-two patients who underwent PMV for symptomatic rheumatic MS (valve area of 0.99±0.3cm²) were prospectively enrolled. LV volumes and LVEF were measured by three-dimensional (3D) echocardiography. Long-term outcome was a composite endpoint of death, mitral valve (MV) replacement, repeat PMV, new onset of atrial fibrillation, and stroke.

RESULTS

The mean age was 42.3±12.1years, and 125 patients were women (88%). After PMV, LVEF increased significantly (51.4 vs 56.5%, p<0.001), primary due to a significant increase in LV end-diastolic volume (65.8mL vs 67.9mL, p=0.002), and resultant increase in the stroke volume (33.9mL vs 39.6mL, p<0.001). Changes in cardiac index and systolic pulmonary artery pressure were associated with LVEF changes after PMV. During a mean follow-up period of 30.8months, 28 adverse clinical events were observed. Postprocedural mitral regurgitation, MV area, and mean gradient were independent predictors of composite endpoints.

CONCLUSIONS

In patients with rheumatic MS, PMV resulted in a significant improvement in LV end-diastolic volume, stroke volume and consequently increased in LVEF. Changes in cardiac index and systolic pulmonary artery pressure were associated with LVEF changes after PMV. The predictors of long-term adverse events following PMV were post-procedural variables, including mitral regurgitation, valve area, and mean gradient.

Update on percutaneous mitral commissurotomy

Percutaneous mitral commissurotomy (PMC) is the first-line therapy for managing rheumatic mitral stenosis. Over the past two decades, the indications of the procedure have expanded to include patients with unfavourable valve anatomy as a consequence of epidemiological changes in patient population. The procedure is increasingly being performed in patients with increased age, more deformed valves and associated comorbidities. Echocardiography plays a crucial role in patient selection and to guide a more efficient procedure. The main echocardiographic predictors of immediate results after PMC are mitral valve area, subvalvular thickening and valve calcification, especially at the commissural level. However, procedural success rate is not only dependent on valve anatomy, but a number of other factors including patient characteristics, interventional management strategies and operator expertise. Severe mitral regurgitation continues to be the most common immediate procedural complication with unchanged incidence rates over time. The long-term outcome after PMC is mainly determined by the immediate procedural results. Postprocedural parameters associated with late adverse events include mitral valve area, mitral regurgitation severity, mean gradient and pulmonary artery pressure. Mitral restenosis is an important predictor of event-free survival rates after successful PMC, and repeat procedure can be considered in cases with commissural refusion. PMC can be performed in special situations, which include high-risk patients, during pregnancy and in the presence of left atrial thrombus, especially in centres with specialised expertise. Therefore, procedural decision-making should take into account the several determinant factors of PMC outcomes. This paper provides an overview and update of PMC techniques, complications, immediate and long-term results over time, and assessment of suitability for the procedure.