Reliability and efficacy of metoprolol and diltiazem in patients having mild to moderate mitral stenosis with sinus rhythm

Therapeutic Controversies in the Medical Management of Valvular Heart Disease

Objective:

To evaluate the evidence for common therapeutic controversies in the medical management of valvular heart disease (VHD).

Data Sources:

A literature search of PubMed (inception to December 2020) was performed using the terms angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) and aortic stenosis (AS); and adrenergic β-antagonists and aortic valve regurgitation (AR) or mitral stenosis (MS).

Study Selection and Data Extraction:

Randomized controlled trials (RCTs) and meta-analyses conducted in humans and published in English that reported ≥1 clinical outcome were included.

Data Synthesis:

Nine articles were included: 3 RCTs and 1 meta-analysis for ACE inhibitors/ARBs in AS, 1 RCT for β-blockers in AR, and 4 RCTs for β-blockers in MS. Evidence suggests that ACE inhibitors/ARBs do not increase the risk of adverse outcomes in patients with AS but may delay valve replacement. β-Blockers do not appear to worsen outcomes in patients with chronic AR and may improve left-ventricular function in patients with a reduced ejection fraction. β-Blockers do not improve and may actually worsen exercise tolerance in patients with MS in sinus rhythm.

Relevance to Patient Care and Clinical Practice:

ACE inhibitors/ARBs and β-blockers can likely be safely used in patients with AS or AR, respectively, who have a compelling indication. There is insufficient evidence to recommend routine use of β-blockers in patients with MS without atrial fibrillation.

Conclusions:

Common beliefs about the medical treatment of VHD are not supported by high-quality data. There remains a need for larger-scale RCTs in the medical management of VHD.

Effect of Ivabradine on Heart Rate and Duration of Exercise in Patients With Mild-to-Moderate Mitral Stenosis: A Randomized Comparison With Metoprolol

Background:

Symptoms in mitral stenosis (MS) are heart rate (HR) dependent. Increase in HR reduces diastolic filling period with rise in transmitral gradient. By reducing HR, beta-blockers improve hemodynamics and relieve symptoms, but the use may be limited by side effects. The present randomized crossover study looked at comparative efficacy of ivabradine and metoprolol on symptoms, hemodynamics, and exercise parameters in patients with mild-to-moderate MS (mitral valve area, 1–2 cm²) in normal sinus rhythm.

Material and Methods:

Baseline clinical assessment, treadmill stress testing, and an echocardiographic Doppler evaluation were performed to determine resting HR, total exercise duration, mean gradient across mitral valve, and mean pulmonary artery systolic pressure (PASP). Patients were then allocated to either metoprolol or ivabradine to maximal tolerated doses over 6 weeks (metoprolol: 100 mg twice a day, ivabradine: 10 mg twice a day). Reevaluation was done at the end of this period, and all drugs stopped for washout over 2 weeks. Thereafter, the 2 groups were crossed over to the other drug that was continued for another 6 weeks. Assessment was again performed at the end of this period.

Results:

Thirty-three patients of 34 completed the protocol. Fifteen were male, mean age was 28.9 ± 6.6 years, all were in New York Heart Association class 2, and mean resting HR was 103.5 ± 7.2/min. Mean mitral valve area was 1.56 ± 0.16 cm², mean PASP was 38.1 ± 5.1 mm Hg, and mean gradient across mitral valve was 10.6 ± 1.6 mm Hg. Significant decrease in baseline and peak exercise HR was observed at the end of follow-up with both drugs. Reduction in mitral valve gradient after ivabradine (42%) and metoprolol (37%) and reduction in PASP after both ivabradine (23%) and metoprolol (27%) were to a similar extent. Significant reduction in total exercise duration after both ivabradine and metoprolol therapy was observed. One patient developed blurring of vision with ivabradine therapy but did not require discontinuation of drug. An improvement in dyspnea of one grade was observed in all the patients by treatment with both ivabradine and metoprolol.

Conclusions:

Both metoprolol and ivabradine reduced symptoms and improved hemodynamics significantly from baseline to a similar extent. Ivabradine thus can be used effectively and safely in patients with MS in normal sinus rhythm who are intolerant or contraindicated for beta-blocker therapy.

Drug Therapy for Heart Valve Diseases

Valvular heart diseases (VHDs) are progressive. When not caused by acute comorbidities they are generally characterized by long asymptomatic phases during which hemodynamic severity may progress leading to morbidity and mortality. Treatment depends on VHD type and severity but when severe and symptomatic, usually involves mechanical intervention. Asymptomatic patients, and those who lack objective descriptors associated with high risk, are closely observed clinically with optimization of associated cardiovascular risk factors until surgical indications develop. Though often prescribed based on theory, no rigorous evidence supports pharmacological therapy in most chronic situations though drugs may be appropriate in acute valvular diseases, or as a bridge to surgery in severely decompensated patients. Herein, we examine evidence supporting drug use for chronic VHDs.