A randomized clinical study evaluating effects of high-intensity interval training on myocardial microvascular dysfunction

Background

Myocardial microvascular function assessed with the Index of Microcirculatory Resistance (IMR) after heart transplantation (HTx) predicts the development of cardiac allograft vasculopathy (CAV) and adverse long-term outcome. This study aimed to evaluate the otherwise beneficial effects of high-intensity interval training (HIT) on microvascular dysfunction development.

Methods

Eighty-one de novo HTx patients were randomized to nine consecutive months of HIT or standard care rehabilitation. Coronary physiology assessment with a pressure wire was performed in the left anterior descending coronary artery. IMR was calculated by multiplying the mean distal coronary pressure by the mean hyperemic transit time. Results obtained at three and twelve months after HTx were compared to assess the treatment effect of HIT.

Results

Results were available for 60 patients. 71% were men, and the mean age was 48±13. IMR in the HIT group (n=26) decreased from 14.8±9.5 to 13.8±8.0, change = 1.2, 95% CI [−2.6 to 4.9] and increased in the standard care group (n=34) from 13.8±5.8 to 16.8±12.0, change = −3.5, 95% CI [−7.1 to 0.1]. The mean difference between groups was 4.7, 95% CI [−9.7 to 0.4], p=0.07.

Conclusion

These results suggest that early initiation of HIT improves microvascular function.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Stiftelsen Dam

The Effect of Everolimus Initiation and Calcineurin Inhibitor Elimination on Cardiac Allograft Vasculopathy in De Novo Recipients: One-Year Results of a Scandinavian Randomized Trial

Early initiation of everolimus with calcineurin inhibitor therapy has been shown to reduce the progression of cardiac allograft vasculopathy (CAV) in de novo heart transplant recipients. The effect of de novo everolimus therapy and early total elimination of calcineurin inhibitor therapy has, however, not been investigated and is relevant given the morbidity and lack of efficacy of current protocols in preventing CAV. This 12-month multicenter Scandinavian trial randomized 115 de novo heart transplant recipients to everolimus with complete calcineurin inhibitor elimination 7-11 weeks after HTx or standard cyclosporine immunosuppression. Ninety-five (83%) patients had matched intravascular ultrasound examinations at baseline and 12 months. Mean (± SD) recipient age was 49.9 ± 13.1 years. The everolimus group (n = 47) demonstrated significantly reduced CAV progression as compared to the calcineurin inhibitor group (n = 48) (ΔMaximal Intimal Thickness 0.03 ± 0.06 and 0.08 ± 0.12 mm, ΔPercent Atheroma Volume 1.3 ± 2.3 and 4.2 ± 5.0%, ΔTotal Atheroma Volume 1.1 ± 19.2 mm(3) and 13.8 ± 28.0 mm(3) [all p-values ≤ 0.01]). Everolimus patients also had a significantly greater decline in levels of soluble tumor necrosis factor receptor-1 as compared to the calcineurin inhibitor group (p = 0.02). These preliminary results suggest that an everolimus-based CNI-free can potentially be considered in suitable de novo HTx recipients.

Osteoprotegerin levels predict mortality in patients with symptomatic aortic stenosis

OBJECTIVES

To examine the prognostic value of osteoprotegerin (OPG) levels in relation to all-cause mortality in patients with symptomatic severe aortic stenosis (AS).

DESIGN

We measured plasma OPG levels in 136 patients with symptomatic severe AS and investigated associations with transvalvular gradients, valve area, valve calcification (using ultrasonic backscatter analysis as an estimate) and measures of heart failure. Then, we assessed the prognostic value of elevated plasma OPG in determining all-cause mortality (n = 29) in these patients.

RESULTS

Elevated OPG was poorly correlated with the degree of AS but was associated with increased backscatter measurements and impaired cardiac function. Furthermore, OPG was associated with all-cause mortality in patients with symptomatic AS, even after adjustment for conventional risk markers. The strongest association was obtained by using a combination of high levels of both OPG and N-terminal pro-brain natriuretic peptide (NT-proBNP), suggesting that these markers may reflect distinct pathways in the development and progression of AS.

CONCLUSION

The level of circulating OPG is significantly associated with all-cause mortality alone and in combination with NT-proBNP in patients with severe symptomatic AS.

Undercarboxylated matrix Gla protein is associated with indices of heart failure and mortality in symptomatic aortic stenosis

OBJECTIVE

Matrix Gla protein (MGP) is a calcification inhibitor and alterations in circulating MGP have been observed in different populations characterized by vascular calcification. We hypothesized that patients with calcific valvular aortic stenosis (AS) would have dysregulated circulating MGP levels.

DESIGN AND SUBJECTS

We examined plasma levels of nonphosphorylated carboxylated and undercarboxylated MGP (dp-cMGP and dp-ucMGP, respectively) in 147 patients with symptomatic severe AS and in matched healthy controls.

MAIN OUTCOME MEASURES

We further investigated the relationship between MGP levels and aortic pressure gradients and valve area by echocardiography and measures of heart failure. Finally, we assessed the prognostic value of elevated plasma dp-ucMGP level in relation to all-cause mortality in patients with AS.

RESULTS

We found markedly enhanced plasma levels of dp-cMGP and in particular of dp-ucMGP in patients with symptomatic AS. Although only weak correlations were found with the degree of AS, circulating dp-ucMGP was associated with cardiac function and long-term mortality in multivariate analysis.

CONCLUSIONS

A dysregulated MGP system may have a role in the development of left ventricular dysfunction in patients with symptomatic AS.