Abnormalities in arterial-ventricular coupling in older healthy persons are attenuated by sodium nitroprusside

The coupling between arterial elastance (E(A); net afterload) and left ventricular elastance (E(LV); pump performance), known as E(A)/E(LV), is a key determinant of cardiovascular performance and shifts during exercise due to a greater increase in E(LV) versus E(A). This normal exercise-induced reduction in E(A)/E(LV) decreases with advancing age. We hypothesized that sodium nitroprusside (SNP) can acutely ameliorate the age-associated deficits in E(A)/E(LV). At rest and during graded exercise to exhaustion, E(A) was characterized as end-systolic pressure/stroke volume and E(LV) as end-systolic pressure/end-systolic volume. Resting E(A)/E(LV) did not differ between old (70 ± 8 yr, n = 15) and young (30 ± 5 yr, n = 17) subjects because of a tandem increase in E(A) and E(LV) in older subjects. During peak exercise, a blunted increase in E(LV) in old (7.8 ± 3.1 mmHg/ml) versus young (11.4 ± 6.5 mmHg/ml) subjects blunted the normal exercise-induced decline in E(A)/E(LV) in old (0.25 ± 0.11) versus young (0.16 ± 0.05) subjects. SNP administration to older subjects lowered resting E(A)/E(LV) by 31% via a reduction in E(A) (10%) and an increase in E(LV) (47%) and lowered peak exercise E(A)/E(LV) (36%) via an increase in E(LV) (68%) without a change in E(A). Importantly, SNP attenuated the age-associated deficits in E(A)/E(LV) and E(LV) during exercise, and at peak exercise E(A)/E(LV) in older subjects on drug administration did not differ from young subjects without drug administration. In conclusion, some age-associated deficiencies in E(A)/E(LV), E(A), and E(LV), in older subjects can be acutely abolished by SNP infusion. This is relevant to common conditions in older subjects associated with a significant impairment of exercise performance such as frailty or heart failure with preserved ejection fraction.