Peripheral microvascular dysfunction is associated with plaque progression and adverse long-term outcomes in heart transplant patients

Aims

Cardiac allograft vasculopathy (CAV) is the major cause of increased morbidity and mortality after heart transplantation. Peripheral endothelial dysfunction (PED) is associated with early atherosclerosis and future risk of major adverse cardiovascular events (MACE) in non‐heart transplant population. We aimed to investigate the association of PED with future MACE, and plaque progression assessed by intravascular ultrasound (IVUS) after heart transplantation.

Methods and results

We included 66 transplant patients who underwent serial IVUS surveillance for CAV and baseline assessment of peripheral endothelial function using reactive hyperaemia peripheral arterial tonometry. PED was defined as reactive hyperaemia index < 2. The primary endpoint of the study was to investigate the association of PED with CAV progression assessed by intravascular ultrasound (IVUS). CAV progression was assessed as the change (Δ) in plaque volume divided by segment length, and Δ plaque index (plaque volume/vessel volume), adjusted for the time between IVUS measurements (median 3.0 [2.2, 3.1] years). The secondary endpoint was to investigate the association between PED and future MACE, which was defined as any incident of revascularization, heart failure hospitalization, stroke, myocardial infarction, re‐transplantation, and death. Patients with PED (n = 27) had more yearly plaque progression (0.50 ± 0.66 vs. 0.15 ± 0.50 mm³/mm/year, P = 0.02) and a higher Δ plaque index (2.41 ± 2.53% vs. 0.69 ± 2.22%, P = 0.01). Patients with PED were more likely to experience MACE during a median follow‐up of 8.2 years (interquartile range [7.6, 8.4]), after adjustment for potential cofounders such as age, high‐density lipoprotein cholesterol levels, total rejection score, baseline International Society for Heart & Lung Transplantation CAV grade, and indication of transplantation. (hazard ratio 2.15, 95% confidence interval [1.09, 4.23], P = 0.03).

Conclusions

Peripheral endothelial dysfunction is associated with increased plaque progression and adverse long‐term cardiovascular outcomes in transplant patients. PED assessment might be a useful clinical tool for risk stratification after heart transplantation.

Impaired endothelial function is not associated with arterial stiffness in adults with type 1 diabetes

AIM

This study investigated the relationship between endothelial dysfunction (ED) and arterial stiffness (AS) in adults with type 1 diabetes and no clinical cardiovascular (CV) disease.

METHODS

A total of 68 patients with type 1 diabetes and 68 age- and gender-matched healthy (non-diabetic) subjects were evaluated. ED was assessed by reactive hyperaemia peripheral arterial tonometry (RH-PAT) and by serum concentrations of soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1) and E-selectin. AS was assessed by aortic pulse wave velocity (aPWV). All statistical analyses were stratified by gender.

RESULTS

Adults with type 1 diabetes had RH-PAT index scores similar to those of their matching controls [men: 1.55 (1.38-1.98)% versus 1.61 (1.40-2.17)%, P=0.556; women: 2.07 (1.55-2.31)% versus 2.08 (1.79-2.49)%; P=0.215]. However, after adjusting for potential confounders, type 1 diabetes emerged as the main determinant of the RH-PAT index in women. Also, differences between genders in both the controls and type 1 diabetes patients disappeared. Men with diabetes had higher serum concentrations of E-selectin, and women had higher serum concentrations of sICAM-1, sVCAM-1 and E-selectin than their respective controls. However, after adjusting for potential confounders, only the differences in sICAM-1 (women) and E-selectin (both genders) remained significant. No association was found between aPWV and the RH-PAT index and ED markers after adjusting for CV risk factors.

CONCLUSION

ED was increased in adults with type 1 diabetes compared with age-matched non-diabetic subjects. Also, gender differences in ED were lost in type 1 diabetes. However, ED was not associated with AS after adjusting for potential confounders. These findings suggest that ED occurs earlier than AS in type 1 diabetes.