Marked Arterial Functional Changes in Patients With Arterial Vascular Events Across the Early Adult Lifespan

Objective:

The age at which arteriosclerosis begins to contribute to events is uncertain. We determined, across the adult lifespan, the extent to which arteriosclerosis-related changes in arterial function occur in those with precipitous arterial events (stroke and critical limb ischemia).

Approaches and Results:

In 1082 black South Africans (356 with either critical limb ischemia [n=238] or stroke [n=118; 35.4% premature], and 726 age, sex, and ethnicity-matched randomly selected controls), arterial function was evaluated from applanation tonometry and velocity and diameter measurements in the outflow tract. Compared with age- and sex-matched controls, over 10-year increments in age from 20 to 60years, multivariate-adjusted (including steady-state pressures) aortic pulse wave velocity, characteristic impedance (Zc), forward wave pressures (Pf), and early systolic pulse pressure amplification were consistently altered in those with arterial events. Increases in Zc were accounted for by aortic stiffness (no differences in aortic diameter) and Pf by changes in Zc and not aortic flow or wave re-reflection. Multivariate-adjusted pulse wave velocity (7.48±0.30 versus 5.82±0.15 m/s, P <0.0001), Zc ( P <0.0005), and Pf ( P <0.0001) were higher and early systolic pulse pressure amplification lower ( P <0.0001) in those with precipitous events than in controls. In comparison to age- and sex-matched controls, independent of risk factors, pulse wave velocity, and Zc ( P <0.005 and <0.05) were more closely associated with premature events than events in older persons and Pf and early systolic pulse pressure amplification were at least as closely associated with premature events as events in older persons.

Conclusions:

Arteriosclerosis-related changes in arterial function are consistently associated with arterial events beyond risk factors from as early as 20 years of age.

Complementary Impact of Carotid Intima-Media Thickness With Plaque in Associations With Noncardiac Arterial Vascular Events

The ability of carotid intima-media thickness (IMT) to predict risk beyond plaque is controversial. In 952 participants (critical limb ischemia [CLI] or stroke, n = 473; community, n = 479), we assessed whether relationships with events for IMT complement the impact of plaque in young patients depending on the extent of thrombotic versus atherosclerotic disease. The extent of atherosclerotic versus thrombotic occlusion was determined in 54 patients with CLI requiring amputations. Thrombotic occlusion in CLI was associated with younger age (P < .0001) and less plaque (P = .02). Independent relations between plaque and CLI were noted in older (>50 years; P < .005 to <.0001) but not younger (P > .38) participants, while independent relations between plaque and stroke (P < .005 to <.0001) and between IMT and CLI (P < .0001) were noted in younger participants. Although in performance (area under the receiver operating curve) for event detection, IMT thresholds failed to add to plaque alone in older patients (0.680 ± 0.020 vs 0.664 ± 0.017, P = .27), IMT improved performance for combined stroke and CLI detection when added to plaque in younger patients (0.719 ± 0.023 vs 0.631 ± 0.026, P < .0001). Because in younger participants the high prevalence of thrombotic occlusion in CLI is associated with less plaque, IMT adds information in associations with arterial vascular events.

Carotid intima-media thickness, but not chronic kidney disease independently associates with noncardiac arterial vascular events in South Africa

AIM

Although chronic kidney disease (CKD) as determined from estimated glomerular filtration rate (eGFR) is recommended for risk prediction by current hypertension guidelines, the equations to derive eGFR may not perform well in black Africans. We compared whether across the adult lifespan, eGFR or CKD are as closely associated with noncardiac arterial vascular events, as carotid intima-media thickness (IMT), in Africa.

METHODS

In 1152 black South Africans [480 with noncardiac arterial events (294 with critical lower limb ischemia, 186 with stroke) of which 37% were premature] and 672 age, sex and ethnicity-matched controls from a randomly selected community sample, we assessed relations between eGFR, CKD or carotid IMT (B-mode ultrasound) and arterial events.

RESULTS

From 20 years until old age, with or without adjustments, IMT was increased in those with as compared with without events (P < 0.01 at each decade of age). However, at any decade of age across the adult lifespan neither creatinine concentrations, nor eGFR were altered in those with arterial events (P > 0.28). Although IMT was strongly and independently associated with the odds of an event [odds ratio per 1 SD (0.171 mm) effect = 2.19, confidence interval = 1.75-2.78, P < 0.0001], neither creatinine concentrations (P = 0.89), modification of diet in renal disease-derived (P = 0.07), nor Chronic Kidney Disease Epidemiology Collaboration-derived [odds ratio per 1 SD (22.5 ml/min per 1.73 m) effect = 1.06, confidence interval = 0.89-1.27, P = 0.51] eGFR were independently associated with the odds of an event. Although many with premature events had an increased IMT (63%), few with either premature events (8%) or with events at an older age (21%) had CKD and CKD had a poor performance (0.539 ± 0.011) and low sensitivity (16%) for event detection.

CONCLUSION

In black South Africans, despite carotid IMT strongly associating with noncardiac arterial vascular events (stroke and critical lower limb ischaemia) consistently across the adult lifespan, few with events have CKD and CKD fails to associate with events.