Ambulatory blood pressure and coronary artery calcification in middle-aged and younger adults

Evaluating the use of coronary artery calcium scoring as a tool for coronary artery disease (CAD) risk stratification and its association with coronary stenosis and CAD risk factors: a single-centre, retrospective, cross-sectional study at a tertiary centre in Pakistan

OBJECTIVE

Coronary artery disease (CAD) risk stratification plays a fundamental role in the early detection and optimal management of CAD. The aim of our study is to investigate the use of coronary artery calcium scoring (CACS) as a tool for CAD risk stratification through evaluation of its correlation with the degree of coronary stenosis and its association with conventional cardiovascular risk factors in asymptomatic patients.

DESIGN

Single-centre, retrospective, cross-sectional study.

SETTING

The study was conducted at a tertiary centre (Shifa International Hospital) in Islamabad, Pakistan, through review of medical records of patients who underwent coronary CT between the years 2016 and 2020.

PARTICIPANTS

A total of 1014 patients were included in the study. The study population was analysed for presence of conventional risk factors (gender, age, diabetes, hypertension, body mass index, dyslipidaemia) and association with CACS (zero: n=534; minimal: 0 to ≤10, n=70; mild: >10 to ≤100, n=130; moderate: >100 to ≤400, n=118; and severe: >400, n=49). The association of CACS with the degree of coronary artery stenosis seen on CT scan (significant: ≥50% stenosis, n=216; non-significant: <50% stenosis, n=685) was also analysed.

OUTCOME MEASURES

The main outcome was the association of coronary artery stenosis with CACS. The secondary outcome was the association of CACS with conventional CAD risk factors.

RESULTS

A significant positive association was shown between CACS and coronary artery stenosis (zero vs minimal: OR 0.39, 95% CI 0.20 to 0.79, p=0.01; zero vs mild: OR 0.16, 95% CI 0.10 to 0.27, p<0.0001; zero vs moderate: OR 0.05, 95% CI 0.03 to 0.08, p<0.0001; zero vs severe: OR 0.02, 95% CI 0.01 to 0.050, p<0.0001). Age >45 (OR 1.03, 95% CI 1.01 to 1.05, p<0.0001), hypertension (OR 1.16, 95% CI 0.79 to 1.71, p=0.001) and diabetes (OR 1.33, 95% CI 0.88 to 1.99, p<0.0001) were associated with an increased risk of coronary artery stenosis. Moreover, plaques with higher calcium burden were found in the left anterior descending artery (mean CACS: 386.15±203.89), followed by right coronary (239.77±219.83) and left circumflex (175.56±153.54) arteries.

CONCLUSION

The results indicate a strong positive association of CACS with coronary artery stenosis. CACS was also significantly associated with conventional CAD risk factors in this population.

Association of ambulatory blood pressure with aortic valve and coronary artery calcification

OBJECTIVE

We aimed to investigate the effect of ambulatory blood pressure (BP) on aortic valve calcification (AVC) and coronary artery calcification (CAC), which are subclinical atherosclerotic diseases.

METHODS

In this population-based, cross-sectional study, we assessed office BP, mean ambulatory BP (24-h, awake, and asleep), and variability of ambulatory BP, as determined by the coefficient of variation (awake and asleep). AVC and CAC were quantified using an Agatston score (>0) based on computed tomography scanning. We calculated relative risks (RRs) and 95% confidence intervals (CIs) with a 1-standard deviation increment in each BP index for the presence of AVC and CAC using a multivariate-adjusted Poisson regression with robust error variance.

RESULTS

Of 483 participants (mean age: 66.8 years), 154 (31.9%) and 310 (64.2%) had AVC and CAC, respectively. The presence of AVC was associated with office systolic BP (SBP; RR, 1.15; 95% CI, 1.03-1.28), awake diastolic BP (DBP) variability (RR, 1.12; 95% CI, 1.01-1.25), and asleep SBP variability (RR, 1.14; 95% CI, 1.03-1.27). The presence of CAC was associated with office SBP (RR, 1.08; 95% CI, 1.01-1.15), mean 24-h SBP (RR, 1.10; 95% CI, 1.04-1.16), mean awake SBP (RR, 1.11; 95% CI, 1.04-1.17), mean asleep SBP (RR, 1.07; 95% CI, 1.01-1.13), and asleep SBP variability (RR, 1.07; 95% CI, 1.01-1.13).

CONCLUSION

These findings highlight the association of ambulatory BP indices with both AVC and CAC, but with different effects on their presences.

Association Between Ambulatory Blood Pressure and Coronary Artery Calcification: The JHS

[Figure: see text].

Diastolic blood pressure predicts coronary plaque volume in patients with coronary artery disease

BACKGROUND AND AIMS

Hypertension is associated with increased clinical and subclinical coronary artery disease (CAD); however, the relationship between blood pressure and coronary plaque volume is unclear. We examined the effect of systolic blood pressure (SBP) and diastolic blood pressure (DBP) on coronary artery plaque volume.

METHODS

285 subjects with stable CAD on statin therapy underwent coronary computed tomographic angiography to measure volume of fatty, fibrous, noncalcified, calcified and total coronary plaque.

RESULTS

Mean (SD) age was 63.1 (7.7); mean (SD) LDL-C, 78.7 mg/dL (28.5). Compared to the highest DBP tertile (>76 mmHg), those in the lowest DBP tertile (≤68 mmHg) had lower volumes of fatty: 10.0 vs. 7.7 mm³/mm, (p trend = 0.042), fibrous: 19.6 vs. 13.8 mm³/mm (p trend = 0.011), non-calcified: 29.7 vs. 22.5 mm³/mm (p trend = 0.017) and total plaque: 37.8 vs. 25.1 mm³/mm (p trend = 0.010) whereas there was no relationship with SBP tertiles. Similarly, when examined as a continuous variable, higher DBP was a significant independent predictor of higher plaque volume after multivariate adjustment: for every 1 mmHg increase in DBP, fibrous plaque increased 0.128 mm³/mm (p = 0.022), noncalcified plaque increased 0.176 mm³/mm (p = 0.045), calcified plaque increased 0.096 mm³/mm (p = 0.001) and total plaque increased 0.249 mm³/mm (p = 0.019) whereas SBP ranging from 95 to 154 mmHg did not predict plaque volume.

CONCLUSIONS

Level of DBP predicts coronary plaque with a DBP tertile ≤68 mmHg associated with the least amount of coronary plaque in subjects with LDL-C < 80 mg/dL.

Loss of nighttime blood pressure dipping as a risk factor for coronary artery calcification in nondialysis chronic kidney disease

Diurnal variations in blood pressure (BP) loss are closely associated with target organ damage and cardiovascular events. The quantity of coronary artery calcification (CAC) correlates with the atherosclerotic plaque burden, and an increased quantity indicates a substantially increased risk of cardiovascular events. This study investigated the nighttime diurnal variation in BP loss associated with CAC in patients with chronic kidney disease (CKD).Of the 1958 participants, we enrolled 722 participants with CKD without a history of acute coronary syndrome or symptomatic coronary artery disease. CAC was measured with computed tomography. BP was measured using 24-hour ambulatory BP monitoring. Central BP was measured using a SphygmoCor waveform analysis system.Participants with CAC had significantly higher 24-hour systolic, daytime systolic, and nighttime systolic ambulatory BP and central systolic BP. The percentage of participants with dipping loss was significantly higher among those with CAC. Multivariate logistic regression analysis indicated that dipping loss and dipping ratio were independently associated with CAC after adjusting for traditional and nontraditional cardiovascular risk factors and other BP parameters, including measurements of office-measured BP and central BP. The dipping status improved risk prediction for CAC after considering traditional risk factors and office-measured BP, using the net reclassification improvement and integrated discrimination improvement.Nighttime loss of diurnal variation in BP is an independent risk factor for CAC in CKD patients.

The Relationship Between Gene Polymorphisms and Dipping Profile in Patients With Coronary Heart Disease

BACKGROUND

The aim of this study is to report the relationship between certain single-nucleotide polymorphisms (SNPs) and blunted nighttime blood pressure (BP) fall in patients with coronary artery disease confirmed by coronary angiography.

METHODS

According to the percentage decrease in mean systolic BP (SBP) and diastolic BP (DBP) during the nighttime period, subjects were classified as dippers or nondippers (nighttime relative SBP or DBP decline ≥10% and <10%, respectively). Genetic risk score (GRS18) was constructed to evaluate additive effect of 18 SNPs for nondipping status.

RESULTS

In the present study, 1,345 subjects with coronary heart disease (CHD) were included. During follow-up period (median 8.3 years, interquartile range 5.3-9.0 years), there were 245 all-cause deaths (18.2%) including 114 cardiovascular deaths (8.5%). There were significant differences in the number of revascularizations between nondippers SBP and DBP and dippers SBP and DBP (48.0% vs. 36.4%, P < 0.01). SNPs of the genes, MIA3, MRAS, PCSK9, SMG6, and ZC3HC1, were related to a higher risk of nondipping SBP and DBP status.

CONCLUSIONS

In the present study, polymorphisms of genes related to CHD (MIA3, MRAS, PCSK9, SMG6, and ZC3HC1) were associated with nondipping SBP and DBP profile, and GRS18 was associated with nondipping status. In addition, this profile was related to a higher risk of revascularization.

Diurnal blood pressure profile and coronary atherosclerosis extent are related to cardiovascular complications

The aim of this study was to assess the relationship between 24 h blood pressure (BP) profile, extent of significant coronary artery stenosis, confirmed by coronary angiography, and cardiovascular events in patients with coronary artery disease. Coronary angiographies were performed for all included subjects and significant coronary artery stenosis was considered as ≥ 50% stenosis by atherosclerotic plaque. Twenty-four-hour ambulatory BP monitoring was performed. Major advanced cardiovascular events (MACE) included revascularization, cardiovascular mortality, total mortality, acute coronary syndromes and stroke. BP analysis revealed higher night-time systolic blood pressure (SBP) values in patients with three or more significant coronary artery stenoses than in those without significant stenosis (120.7 ± 16.4 vs 116.7 ± 14.3 mmHg, p < 0.001), lower night-time SBP dip in patients with three or more significant coronary artery stenoses than in those without significant stenosis (5.7 ± 3.2 vs 7.4 ± 6.8 mmHg, p < 0.001) and lower night-time diastolic blood pressure dip in patients with three or more significant stenoses than in patients without significant stenosis (9.4 ± 7.4 vs 11.9 ± 7.4 mmHg, p < 0.001). Night-time SBP values, night-time/daytime SBP dip and extent of significant coronary artery stenosis were risk factors for MACE, revascularization and cardiovascular mortality. In conclusion, the study shows that advanced coronary artery disease is related to blunted night-time BP dipping and cardiovascular complications.

An increase in the coronary calcification score is associated with an increased risk of heart failure in patients without a history of coronary artery disease

BACKGROUND

The presence of coronary artery calcification (CAC) and its severity predict future cardiovascular events and is used for risk stratification. However, the association of CAC with heart failure (HF) in patients without a history of coronary artery disease (CAD) remains unclear. This study aimed to determine the correlations of CAC with N-terminal pro-B-type natriuretic peptide (NT-proBNP) and HF events in patients without a history of CAD or HF.

METHODS

From June 2010 to June 2013, a total of 487 patients without a history of CAD and HF were enrolled. All of the patients underwent plane multi-detector computed tomography. They were divided into four categories according to CAC scores: ≤10, 11-100, 101-400, and ≥401.

RESULTS

The proportion of patients with high NT-proBNP levels increased with CAC categories (p<0.0001). The CAC score was associated with NT-proBNP levels ≥400pg/ml, with an odds ratio of 2.901 (95% confidence interval: 1.368-6.151, p=0.0055) for CAC scores ≥401 compared with CAC scores of 0-10 after adjustment for confounding factors. During the follow-up period of 497±315 days, nine patients were admitted for HF. Kaplan-Meier analysis showed that patients with CAC scores ≥401 had a lower rate of freedom from admission for HF with cumulative incidences of 0.4%, 1%, 2%, and 8% for CAC scores of 0-10, 11-100, 101-400, and ≥401, respectively (p<0.0001). Increasing CAC scores were associated with an increase in incidence of admission for HF, with a hazard ratio of 10.371 for CAC scores ≥401 (95% CI: 1.062-101.309, p=0.0443) compared with CAC scores of 0-10 after adjustment for risk factors.

CONCLUSION

Severe CAC is an independent determinant of high NT-proBNP levels and a predictor of admission for HF in a population without a history of CAD or HF.

Nighttime blood pressure dipping in young adults and coronary artery calcium 10-15 years later: the coronary artery risk development in young adults study

Nighttime blood pressure (BP) dipping can be quantified as the ratio of mean nighttime (sleep) BP to mean daytime (awake) BP. People whose dipping ratio is ≥ 0.90 have been referred to as nondippers, and nondipping is associated with cardiovascular disease events. We examined the relationship between systolic nighttime BP dipping in young adults and the presence of coronary artery calcium (CAC) 10 to 15 years later using data from the ambulatory BP monitoring substudy of the Coronary Artery Risk Development in Young Adults Study. Among 239 participants with adequate measures of both nighttime and daytime readings and coronary artery calcium, the systolic BP dipping ratio ranged from 0.72 to 1.24 (mean, 0.88; SD, 0.06), and CAC was present 10 to 15 years later in 54 participants (22.6%). Compared with those whose systolic BP dipping ratio ranged from 0.88 to 0.92 (quartile 3), the 57 participants (23.9%) with less pronounced or absent dipping (ratio, 0.92-1.24; quartile 4) had an unadjusted odds ratio of 4.08 (95% CI, 1.48-11.2) for the presence of CAC. The 60 participants (25.1%) with a more pronounced dipping (ratio, 0.72-0.85; quartile 1) also had greater odds for presence of CAC (odds ratio, 4.76 [95% CI, 1.76-12.9]). When modeled as a continuous predictor, a U-shaped relationship between systolic BP dipping ratio and future CAC was apparent and persisted after adjustment for multiple potential confounders (P<0.001 for quadratic term). Both failure of systolic BP to dip sufficiently and "overdipping" during nighttime may be associated with future subclinical coronary atherosclerosis.

Aortic pulse wave velocity is associated with measures of subclinical target organ damage

OBJECTIVES

Our goal was to evaluate the associations of central arterial stiffness, measured by aortic pulse wave velocity (aPWV), with subclinical target organ damage in the coronary, peripheral arterial, cerebral, and renal arterial beds.

BACKGROUND

Arterial stiffness is associated with adverse cardiovascular outcomes. We hypothesized that aPWV is associated with subclinical measures of atherosclerosis-coronary artery calcification (CAC) and ankle-brachial index (ABI) and arteriolosclerosis-brain white matter hyperintensity (WMH) and urine albumin-creatinine ratio (UACR).

METHODS

Participants (n = 812; mean age 58 years; 58% women, 71% hypertensive) belonged to hypertensive sibships and had no history of myocardial infarction or stroke. aPWV was measured by applanation tonometry, CAC by electron beam computed tomography, ABI using a standard protocol, WMH volume by brain magnetic resonance, and UACR by standard methods. WMH was log-transformed, whereas CAC and UACR were log-transformed after adding 1 to reduce skewness. The associations of aPWV with CAC, ABI, WMH, and UACR were assessed by multivariable linear regression using generalized estimating equations to account for the presence of sibships. Covariates included in the models were age, sex, body mass index, history of smoking, hypertension and diabetes, total and high-density lipoprotein cholesterol, estimated glomerular filtration rate, use of aspirin and statins, and pulse pressure.

RESULTS

The mean ± SD aPWV was 9.8 ± 2.8 m/s. After adjustment for age, sex, conventional cardiovascular risk factors, and pulse pressure, higher aPWV (1 m/s increase) was significantly associated with higher log (CAC + 1) (β ± SE = 0.14 ± 0.04; p = 0.0003), lower ABI (β ± SE = -0.005 ± 0.002; p = 0.02), and greater log (WMH) (β ± SE = 0.03 ± 0.009; p = 0.002), but not with log (UACR + 1) (p = 0.66).

CONCLUSIONS

Higher aPWV was independently associated with greater burden of subclinical disease in coronary, lower extremity, and cerebral arterial beds, highlighting target organ damage as a potential mechanism underlying the association of arterial stiffness with adverse cardiovascular outcomes.

Association between arterial pressure and coronary artery calcification

OBJECTIVES

Coronary artery calcification (CAC) determined by electron beam computed tomography is a predictor of future cardiovascular events. This study investigates conditions affecting CAC severity in patients with coronary artery disease (CAD) undergoing coronary angiography.

METHODS

Presence and degree of CAC were assessed angiographically in 877 CAD patients grouped into no visible CAC (n = 333), mild to moderate CAC (n = 321), and severe CAC (n = 223). Regression analyses investigated relationships between CAC and demographic data, cardiovascular risk factors, and coronary anatomy.

RESULTS

Prevalences of hypertension and systolic blood pressure (SBP) values were higher in individuals with CAC (moderate CAC: 49.5%, 137.5 +/- 18.6 mmHg; severe CAC: 58.3%, 142.1 +/- 20.4 mmHg) compared to individuals with CAD but no CAC (42.0%, 134.0 +/- 18.4 mmHg; both P < 0.001). Likewise, pulse pressure was significantly elevated with increasing degree of CAC (no CAC, 52.3 +/- 13.6 mmHg vs moderate CAC, 55.7 +/- 14.4 mmHg vs severe CAC, 59.1 +/- 15.4 mmHg; P < 0.001). Further determinants of CAC were age, positive family history for CAC and severity of CAD. No differences in CAC severity were found in relation to body mass index, low-density lipoprotein-cholesterol, diabetes, and smoking habits. In multivariate analysis, CAC was independently related to age, SBP or pulse pressure, respectively, positive family history for CAC, and the severity of CAD.

CONCLUSIONS

Of the cardiovascular risk factors, SBP and pulse pressure display the strongest relationship with angiographic detection of CAC. Mechanistic studies need to clarify whether hypertension causes CAC, or whether coronary calcium deposition serves as a marker for a higher degree of vascular calcification and, thus, impaired vascular compliance and higher blood pressure levels.

Association of plasma homocysteine with coronary artery calcification in different categories of coronary heart disease risk

OBJECTIVE

To Investigate the association of plasma homocystelne with coronary artery calcification (CAC) in strata based on 10-year risk of coronary heart disease (CHD) in a cohort enriched in persons with hypertension.

PARTICIPANTS AND METHODS

Fasting plasma homocystelne was measured by liquid chromatography electrospray tandem mass spectrometry. Coronary artery calcification was measured noninvasively by electron beam computed tomography and CAC score calculated using the method of Agatston et al. The 10-year CHD risk was calculated based on the Framingham risk score. The association of homocysteine with log-transformed CAC score was assessed in the pooled sample and within each risk stratum by linear regression after adjustment for conventional risk factors.

RESULTS

In the 1071 participants studied, homocysteine was associated with CAC quantity (P = .01) after adjustment for CHD risk factors (age, male sex, total and high-density lipoproteln cholesterol, diabetes, history of smoking, body mass Index, and systolic blood pressure), serum creatinine, and statin and hypertension medication use. When the association was assessed in strata based on 10-year CHD risk, homocysteine was significantly (P = .003) associated with CAC quantity in participants at Intermediate 10-year risk of CHD (6%-20%) independent of other risk factors but not in those at lower risk or higher risk.

CONCLUSION

Plasma homocysteine is associated with quantity of CAC Independent of CHD risk factors. When studied in categories of 10-year CHD risk, the association was significant in participants at intermediate risk but not in those at low or high risk. Plasma homocysteine levels may have clinical utility as a marker of CHD risk in such individuals.

Age and gender are the strongest clinical correlates of prevalent coronary calcification (R1)

OBJECTIVE

To determine which of the standard cardiovascular risk factors have the strongest associations with prevalent coronary artery calcification (CAC).

STUDY DESIGN AND SETTING

A cross-sectional study of 6086 consecutive subjects who underwent electron beam computed tomography for CAC at a private, university-affiliated disease prevention center in San Diego, CA.

RESULTS

The correlation between age and coronary calcium score in men (r=0.463) was twice that of the next highest correlation (0.218) for percent body fat. A similar relationship was found for women (0.413 vs. 0.238). Calcium scores increased incrementally by age category in both men and women. This pattern of increase was not present for LDL cholesterol. Men and women over the age of 74 had highly elevated risks for the presence of any calcified coronary atherosclerosis compared to those under the age of 45 (OR [95% CI]: 11.08 [6.186-19.859] and 11.81 [6.718-20.746], respectively). Addition of the other traditional cardiovascular risk factors did not significantly increase the discriminatory power beyond that provided by age on ROC analysis.

CONCLUSION

Age and gender are significant independent clinical correlates of coronary calcium beyond that provided by the other risk factors. These results support the hypothesis that age is the predominant risk factor for coronary calcification.

Lack of association between lipoprotein(a) and coronary artery calcification in the Genetic Epidemiology Network of Arteriopathy (GENOA) study

OBJECTIVE

To investigate the relationship between lipoprotein(a) [Lp(a)] levels and the extent of coronary atherosclerosis in a cohort that consisted predominantly of hypertensive patients.

PATIENTS AND METHODS

Patients were ascertained through sibships that contained at least 2 individuals with essential hypertension diagnosed before the age of 60 years. The 10-year coronary heart disease (CHD) risk was estimated on the basis of the Framingham risk equation. Serum Lp(a) was measured by an immunoturbidimetric assay. Coronary artery calcification (CAC) was measured noninvasively by electron beam computed tomography and CAC score calculated using the Agatston score.

RESULTS

Patients included 765 non-Hispanic, white individuals (59% women) participating in the Genetic Epidemiology Network of Arteriopathy study. The mean +/- SD age of the patients was 62 +/- 8 years, and 77% had hypertension. The prevalence of detectable CAC was 87% in men and 60% in women. The CAC scores did not differ significantly across quintiles of Lp(a) levels in either men or women. In a multiple regression model that included conventional risk factors, Lp(a) levels were not related to CAC quantity in either sex. No significant interactions were noted between Lp(a) levels and the conventional risk factors in the prediction of CAC quantity. When stratified on the basis of the 10-year CHD risk, 26.5% of the patients were low risk (< 6%), 60.5% were intermediate risk (6%-20%), and 12.9% were high risk (> 20%). Lipoprotein(a) was not associated with CAC quantity within subgroups based on 10-year CHD risk.

CONCLUSION

In this cohort enriched with hypertensive patients, the estimated 10-year CHD risk did not appear to modify the lack of an association between Lp(a) levels and CAC.

Coronary artery calcification and cardiovascular risk factors: impact of the analytic approach

Coronary artery calcification (CAC) may help identify novel risk factors for coronary atherosclerosis. However, analysis of CAC is challenging because of the distribution of CAC in the population. This has resulted in difficulty in interpreting and comparing results across studies. We applied several analytic approaches to CAC data in order to determine the impact of analytic methods on the association with established cardiovascular risk factors in 914 asymptomatic subjects in the Study of Inherited Risk Factors for Coronary Atherosclerosis. Multivariable analyses included: (1) linear regression of different transformations of CAC scores; (2) tobit regression of the log of (CAC + 1); (3) logistic regression using CAC zero as a cut-point; and (4) ordinal logistic regression using CAC categories. Linear regression of the log CAC scores and logistic regression of CAC zero cut-point failed to detect associations with some risk factors. In contrast, linear and tobit regression of the log (CAC + 1) and ordinal regression of CAC categories identified more associations and provided consistent results. Commonly applied methods of CAC analysis may fail to detect associations with cardiovascular risk factors. We present analytic approaches that are likely to provide consistent results and recommend the use of at least two distinct multivariable methods.

Reactivity as a predictor of subsequent blood pressure: racial differences in the Coronary Artery Risk Development in Young Adults (CARDIA) Study

This study investigated the association between cardiovascular reactivity and subsequent ambulatory blood pressure in 316 black and white men and women in the Coronary Artery Risk Development in Young Adults (CARDIA) Study. Cardiovascular laboratory reactivity was examined in subjects 20 to 33 years old, and ambulatory blood pressure and heart rate were measured 3 years later. Average ambulatory pressure during a 24-hour period was regressed separately on stress reactivity and standard covariate risk factors in each race/gender subgroup. Blacks had higher blood pressure and heart rates than whites, men had higher blood pressure than women, and women had higher heart rates than men. After controlling for age, baseline systolic pressure, familial history of hypertension, smoking, alcohol consumption, body mass index, and exercise, systolic blood pressure reactivity to star tracing and cold pressor stress were significantly associated with systolic ambulatory pressure in black men and women 3 years later (partial r=0.24 to 0.37). Heart rate reactivity to video challenge and star tracing were also significantly predictive of subsequent ambulatory heart rate in blacks. Diastolic star tracing reactivity was significantly associated with subsequent ambulatory blood pressure in black women (r=0.23), and diastolic reactivity to video and star tracing were significantly predictive of ambulatory diastolic pressure in white men (r=0.39). We conclude that hyperresponsivity to stress may be a risk factor for subsequent blood pressure elevation in blacks and may be one pathway leading to the higher prevalence of hypertension in blacks than in whites.