Effect of digoxin and vasodilators on left ventricular function in aortic regurgitation

Sex Differences in the Anti-Hypertensive Effect of Calcium-Channel Blockers: A Systematic Review and Meta-Analysis

Cardiovascular disease (CVD) is the number one cause of death worldwide, with hypertension as the leading risk factor for both sexes. As sex may affect responsiveness to antihypertensive compounds, guidelines for CVD prevention might necessitate divergence between females and males. To this end, we studied the effectiveness of calcium channel blockers (CCB) on blood pressure (BP), heart rate (HR) and cardiac function between sexes. We performed a systematic review and meta-analysis on studies on CCB from inception to May 2020. Studies had to present both baseline and follow-up measurements of the outcome variables of interest and present data in a sex-stratified manner. Mean differences were calculated using a random-effects model. In total, 38 studies with 8202 participants were used for this review. In females as compared to males, systolic BP decreased by -27.6 mmHg (95%CI -36.4; -18.8) (-17.1% (95%CI -22.5;-11.6)) versus -14.4 mmHg (95%CI -19.0; -9.9) (-9.8% (95%CI -12.9;-6.7)) (between-sex difference p < 0.01), diastolic BP decreased by -14.1 (95%CI -18.8; -9.3) (-15.2%(95%CI -20.3;-10.1)) versus -10.6 mmHg (95%CI -14.0; -7.3) (-11.2% (95%CI -14.8;-7.7)) (between-sex difference p = 0.24). HR decreased by -1.8 bpm (95%CI -2.5; -1.2) (-2.5% (95%CI -3.4; -1.6)) in females compared to no change in males (0.3 bpm (95% CI -1.2; 1.8)) (between-sex difference p = 0.01). In conclusion, CCB lowers BP in both sexes, but the observed effect is larger in females as compared to males.

Vasodilator therapy in patients with aortic insufficiency: a systematic review

BACKGROUND

The use of vasodilators to improve long-term outcomes in asymptomatic patients with chronic aortic insufficiency (AI) is controversial.

METHODS

We reviewed MEDLINE, PREMEDLINE, Current Contents, and Cochrane databases to identify relevant clinical trials on asymptomatic patients with chronic AI of at least moderate severity. We included those studies that involved long-term vasodilator therapy (including hydralazine, calcium-channel blockers, and angiotensin-converting enzyme inhibitors) and assessed either hemodynamic and structural parameters or clinical outcomes. Data on patient demographics, study protocols, and outcomes were abstracted.

RESULTS

Ten studies with 544 asymptomatic patients with chronic AI were identified. Treatment duration with vasodilators ranged from 12 weeks to 7 years. Of these, 8 studies compared vasodilators with placebo or no therapy, with 5 demonstrating improvements in at least 1 hemodynamic or structural parameter with vasodilators and 3 showing little or no apparent benefit. The remaining 2 studies directly compared outcomes between 2 different vasodilators. Both of these studies demonstrated greater improvements in hemodynamic and structural parameters with angiotensin-converting enzyme inhibitors compared with hydralazine and nifedipine. Clinical outcomes were primarily reported in only 2 of the 10 studies. Although one study suggested that the use of vasodilators slowed the rate of progression to surgery for aortic valve replacement, another showed no difference.

CONCLUSIONS

Vasodilators inconsistently improve hemodynamic and structural parameters in asymptomatic patients with chronic AI. In addition, the impact of vasodilators on clinical outcomes is largely uncertain and requires further study.

Aortic insufficiency: defining the role of pharmacotherapy

Major advances in the diagnostic, evaluation, and particularly surgical treatment of aortic regurgitation (AR) have redefined the role of medical treatment. In acute AR, aortic valve replacement (AVR) is the only life-saving treatment. Medical treatment may improve the hemodynamic state temporarily before surgery. Rationale of medical treatment in chronic AR is based on the natural history and pathophysiology of the disease. The primary goal is to optimize the time of the AVR. If there is any symptom and/or left ventricular (LV) dysfunction, early AVR is required. Vasodilators should only be considered as a short-term treatment before surgery if there is evidence of severe heart failure or as a long-term treatment if AVR is contraindicated because of cardiac or noncardiac factors. In asymptomatic patients with severe chronic AR and normal LV function (even if the left ventricle is moderately dilated), vasodilators may prolong the compensated phase of chronic AR, although proof of their efficacy in delaying AVR is limited. Nifedipine is the best evidence-based treatment in this indication. ACE inhibitors are particularly useful for hypertensive patients with AR. beta-Adrenoceptor antagonists (beta-blockers) may be indicated to slow the rate of aortic dilatation and delay the need for surgery in patients with AR associated with aortic root disease. Furthermore, they may improve cardiac performance by reducing cardiac volume and LV mass in patients with impaired LV function after AVR for AR.

Timing of surgery in chronic aortic regurgitation

When deciding on therapy for aortic regurgitation (AR), it is imperative to distinguish between acute and chronic AR. Symptoms and echocardiographic findings are essential in distinguishing acute from chronic AR and in assessing the severity. Vasodilators have been shown to be helpful in treating patients with chronic severe AR. The timing of aortic valve replacement in chronic severe AR remains controversial. Symptoms, left ventricular function, and response to exercise have been shown to be the most important prognostic indicators.

Nifedipine in asymptomatic patients with severe aortic regurgitation and normal left ventricular function

BACKGROUND

Vasodilator therapy with nifedipine reduces left ventricular volume and mass and increases the ejection fraction in asymptomatic patients with severe aortic regurgitation.

METHODS

To assess whether vasodilator therapy reduces or delays the need for valve replacement, we randomly assigned 143 asymptomatic patients with isolated, severe aortic regurgitation and normal left ventricular systolic function to receive either nifedipine (20 mg twice daily, 69 patients) or digoxin (0.25 mg daily, 74 patients).

RESULTS

By actuarial analysis, we determined that after six years a mean (+/- SD) of 34 +/- 6 percent of the patients in the digoxin group had undergone valve replacement, as compared with only 15 +/- 3 percent of those in the nifedipine group (P < 0.001). In the digoxin group, valve replacement (in a total of 20 patients) was performed because of left ventricular dysfunction (ejection fraction < 50 percent) in 75 percent, left ventricular dysfunction plus symptoms in 10 percent, and symptoms alone in 15 percent. In the nifedipine group, all six patients who underwent valve replacement did so because of the development of left ventricular dysfunction. In addition, all the patients in both groups who underwent aortic-valve replacement had an increase of 15 percent or more in the left ventricular end-diastolic volume index. After aortic-valve replacement, 12 of the 16 patients (75 percent) in the digoxin group and all six patients in the nifedipine group who had had an abnormal left ventricular ejection fraction before surgery had a normal ejection fraction.

CONCLUSIONS

Long-term vasodilator therapy with nifedipine reduces or delays the need for aortic-valve replacement in asymptomatic patients with severe aortic regurgitation and normal left ventricular systolic function.