Sex differences in diastolic blood pressure changes with age using 24-hour ABPM in 30,513 patients

Background

We have previously shown, using 24-hour ABPM monitoring, that diastolic blood pressure (DBP) in a large referral population, containing both males and females, increases until age 42 years, following which DBP falls progressively. This occurs in the hypertensive population some 13 years sooner than previous general population studies. There is conflicting emerging data on sex differences in the lifelong trajectory of both systolic and diastolic blood pressure.

Purpose

To examine sex-specific patterns of diastolic blood pressure throughout the lifespan of patients referred for 24-hour ABPMs.

Methods

Our database was searched for all 24-hour ABPMs. We used the average 24-hour SBP and DBP for this analysis. Scatter grams were produced for age versus systolic BP (SBP) and DBP for both males and females. Second order polynomial regression was performed on the DBP scatter grams for both genders and their inflection points calculated. The inflection point is the age at which the DBP on the polynomial curve where the slope changes from positive to negative. This, inflection point, corresponds to the age at which DBP begins to decrease. The DBP polynomial curves for males and females were then superimposed to show any gender differences.

Results

There were 30,513 24-hour analysable ABPMs over 24 years, representing 97% of all ABPMs. There were 15,913 females aged 60.8±14.6 years (range 15–97 years) and 14,600 males aged 58.8±14.2 years (range 15–100 years). As can be seen from the charts below, in females DBP begins to fall at a very early age of 22.3 years, whereas in males the diastolic BP begins to fall at 46.5 years.

Conclusions

There are significant sex differences in the changes in DBP with increasing age. For the first 35 years DBP is higher in women, thereafter DBP is lower in females and only intersects again much later in life at 95 years. The significance of this sex difference is unclear but may explain the increased prevalence of systolic hypertension in elderly females.

Figure 1

Funding Acknowledgement

Type of funding source: None

P1371 The effect of ideal BSA in patients with low-flow, low-gradient severe aortic stenosis

INTRODUCTION

The current obesity epidemic has an impact on calculated BSA, significantly increasing the calculated BSA from what the ideal BSA would be if based on a patient’s ideal body weight.

PURPOSE

To determine the effect of ideal BSA on AV area index in patients with low-flow, low-gradient severe aortic stenosis and normal left ventricular function.

METHODS

Our ECHO database was searched for all patients with an LVEF >50%, a mean aortic gradient of <40 mmHg, an AV area <1.00cm2, AVA index <0.60cm2/m2 and SV index <35ml/m2. Patients with atrial fibrillation, mechanical and bioprosthetic valves, any valve repair, HOCM, Amyloidosis, more than mild aortic regurgitation, moderate mitral regurgitation, any wall motion abnormality despite normal LVEF, Pacemaker or ICD or a moderate pericardial effusion were excluded. Ideal weight was calculated using the Devine formula = Constant + 2.3 x [height in inches-60], where constant= 50Kg in males and 45.5Kg in females). Body surface area in m2 was calculated using the formula = [√ (height in cm x weight in kg)/3600]. The paired t-test was used to determine differences between means and the Fisher’s exact test was used to determine differences between proportions. A p value of <0.05 was considered significant.

RESULTS

There were 73 females (mean age 76.2 ± 11.3 years, mean AV gradient 27.2 ± 7.4 mmHg, mean AVA 0.82 ± 0.11 cm2 and mean LVEF of 64.9 ± 5.4%) and 55 males (mean age 76.1 ± 9.8 years, mean AV gradient 29.9 ± 7.2 mmHg, mean AVA 0.85 ± 0.11 cm2and mean LVEF of 62.2 ± 5.7%). Other important variables are seen in table 1. Based on the corrected ideal BSA there were 0 of 55 male patients who were re-assigned to the moderate AS category, compared to 25 of 73 (34.2%) female patients (P < 0.0001, Fisher’s exact test).

CONCLUSIONS

Use of the corrected ideal BSA has no effect on the hemodynamic diagnosis of low-flow, low gradient, normal LVEF severe aortic stenosis in males, but has a significant effect of the same diagnosis in females. It is therefore recommended that ideal body weight and ideal BSA be used when calculating AVA index in female patients suspected of low-flow, low-gradient severe aortic stenosis with normal ventricular function.

Weight(M) Weight(F) BSA(M) BSA(F) AVAI(M) AVAI(F) SVI(M) SVI(F) Actual 82.6 ± 12.5 70.1 ± 13.5 1.95 ± 0.15 1.71 ± 0.16 0.44 ± 0.06 0.48 ± 0.07 25.9 ± 4.9 23.9 ± 5.1 Ideal 67.5 ± 6.8 49.7 ± 5.4 1.79 ± 0.13 1.47 ± 0.11 0.48 ± 0.07 0.56 ± 0.08 28.3 ± 5.5 27.7 ± 6.3 P value <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 (M)=male, (F)=female, weight in kg, BSA in m2, AVAI in cm2/m2, SVI in ml/m2.

P296 The effect of ideal BSA in patients with moderate aortic stenosis?

INTRODUCTION

The current obesity epidemic has an impact on calculated BSA. Obesity significantly increases the calculated BSA from what the ideal BSA would be if based on a patient’s ideal body weight.

PURPOSE

To determine the effect of ideal BSA on AV area index in patients with moderate aortic stenosis and normal left ventricular function.

METHODS

Our ECHO database was searched for all patients with an LVEF >50% and moderate aortic stenosis based on a mean aortic gradient of 20-39 mmHg and an AV area >1.00 cm2. Patients with more than mild aortic regurgitation, previous valvular repair or replacement, significant mitral valve disease or any LV wall motion abnormalities were excluded. Ideal weight was calculated using the Devine formula = Constant + 2.3 x [height in inches-60], where constant= 50Kg in males and 45.5Kg in females). Body surface area in m2 was calculated using the formula = [√ (height in cm x weight in Kg)/3600]. The paired t-test was used to determine differences between means and the Fisher’s exact test was used to determine differences between proportions. A p value of <0.05 was considered significant.

RESULTS

There were 210 females (mean age 75.4 ± 11.9 years, mean AV gradient 25.3 ± 4.8 mmHg, mean AVA 1.28 ± 0.27 cm2) and 385 males (mean age 72.7 ± 11.3 years, mean AV gradient 25.9 ± 5.2 mmHg, mean AVA 1.32 ± 0.28 cm2). Other important variables are seen in table 1. There were highly significant differences between actual and ideal measurements of weight, BSA and AV area index. Based on the actual BSA there were 151 of 385 male patients (39.2%) with severe aortic stenosis (<0.60 cm2/m2), which dropped to 66 of 385 patients (17.1%) when the ideal BSA was used in the calculation (P < 0.0001, Fisher’s exact test). For females there were 44 of 210 patients with severe aortic stenosis (21.0%) which dropped to 3 (1.4%) when the ideal BSA was used in the calculation (P < 0.0001, Fisher’s exact test).

CONCLUSIONS

Use of the ideal BSA, based on ideal weight, significantly reclassifies women in terms of AS severity and will be consistent throughout time. All mean aortic gradients and AV areas, by definition, and 98.6% of the ideal AV area indices being in the moderate AS range. The data is less compelling in males but is still significantly improved with 82.9% of AV area indices being correctly assigned.

Table 1. Weight/kg (Females) Weight/kg (Males) BSA/m2 (Females) BSA/m2 (Males) AVAI (Females) AVAI (Males) Actual. 77.5 ± 21.4 90.1 ± 16.9 1.79 ± 0.23 2.04 ± 0.20 0.72 ± 0.16 0.65 ± 0.14 Ideal. 51.6 ± 6.2 69.3 ± 7.1 1.51 ± 0.12 1.83 ± 0.14 0.85 ± 0.17 0.73 ± 0.16 P value. <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 AVAI = Aortic valve area index (cm2/m2). BSA = Body surface area (m2).

1681 Carotid screening prior to stress echocardiography, an opportunity to assess cardiovascular risk?

BACKGROUND

Screening for atherosclerosis is an important method for assessing cardiovascular (CV) risk. Our data with carotid imaging shows a normal a carotid is associated with a very low 10-year CV risk of 1.6%. Even a low risk carotid still predicts a favourable outcome, 5.6-7.0% CV risk over 10 years. Increasing plaque burden as assessed by either total plaque area (>25mm2) or plaque score (>1) is associated with increasing CV risk, ranging from 20% to >30% over 10 years.

PURPOSE

This analysis was performed to estimate the prevalence and severity of carotid disease in men and women presenting for stress ECHO, with no prior documented evidence of CV disease.

METHODS

Data was collected from October 3, 2011 to January 22, 2019. Male patients aged 40-70yrs and female patients aged 50-75yrs undergoing stress ECHO underwent a screening carotid examination prior to the test. This involves only 2-3 images on each side to include, the CCA, carotid bulb and ICA. Maximal CCA IMT is measured using an automatic edge detection method, plaque score is calculated using the Rotterdam method and plaque area is measured in the carotid bulb and ICA bilaterally. Total plaque area being the sum of all area measurements. Apart from age criteria, patients were also excluded if they were diabetic, already taking a statin, or had a previous history of any vascular disease. A low-risk carotid was defined as a maximal CCA IMT <1.00m,with a plaque score of "0" or "1" providing the total plaque area was <25mm2. An unpaired t-test was used to detect differences between means and the Fisher’s exact test was used to detect differences between proportions. A p value of <0.05 was considered statistically significant.

RESULTS

There were 1683 patients, 1175 females and 508 males with a mean age of 60.9 ± 7.4 years. Of the 1683 patients 1058 had evidence of carotid plaque (62.9%), 368 males (72.4%) and 690 females (58.7%). 726 patients were classified as low-risk and 957 patients were classified as high-risk. See Table 1.

CONCLUSIONS

A brief screening carotid examination prior to stress ECHO reveals a large percentage of both men and women who have evidence of atherosclerosis, of which 56.9% are high-risk. These patients could be identified while in the ECHO laboratory. The patients could then be offered guideline therapy with statin therapy and low dose ASA.

Table 1. Number Age CCA IMT PS 0-1 PS 2-3 PS 4-6 Low-risk High-risk Males 508 58.4 ± 7.8 1.14 ± 0.47 138 213 56 161 347 Females 1175 62.0 ± 7.0 0.99 ± 0.49 726 395 54 565 610 P value <0.0001 <0.0001 <0.0001 <0.005 <0.0001 <0.0001 <0.0001 PS = Plaque score.

P758 Should ECHO measurements be indexed to ideal BSA or actual BSA?

INTRODUCTION

A patient with aortic stenosis with an AVA of 1.22 cm2 who stands 5’ 6" and weighs 145 lb has a BSA of 1.76m2 (AV area index = 0.69 cm2/m2). If the same patient weighs 200 lbs, the BSA increases to 2.09 m2 (AV area index 0.58 cm2/m2). Their calculated AV area index therefore changes from the moderate range to the severe range.

PURPOSE

To determine from our ECHO database the effect the current obesity epidemic has on all ECHO variables that are indexed to BSA.

METHODS

Our ECHO database was searched for all patients with the required data variables, gender, age, height (cm)and body weight (kg) were required. Duplicate patients with multiple ECHO studies were removed, only the first ECHO entry being included. Obvious data entry errors were removed (e.g. height 1866 cm, or weight 8.6 kg). Ideal weight was calculated using the Devine formula, ideal weight = Constant + 2.3x[height in inches-60], where constant= 50kg in males and 45.5kg in females. Body surface area in m2 was calculated = [√(height in cm x weight in Kg)/3600]. The paired t-test was used to determine differences between means. A p value of <0.05 was considered significant.

RESULTS

There were 47,761 ECHO studies entered into the database, of which 46,605 (98%) had all the required fields completed. Once duplicates were removed (-15,903) and erroneous data deleted (-158, 0.33%), 30,536 remained. There were 16,160 females aged 58.7 ± 19.2 years, with a mean height of 161.7 ± 7.2cm and 14,376 males aged 59.8 ± 19.2 years, with a mean height of 176.7 ± 7.6 cm. There were statistically significant differences in both men and women between actual and ideal weight and actual and ideal BSA, see Table 1.

CONLUSIONS. For all ECHO measurements where the value is frequently indexed a decision needs to be made to either use the actual BSA or the ideal BSA. It may be more practical to use the ideal BSA which will remain consistent throughout follow up. Using our data any such measurement for females could be multiplied by 1.16 and for males 1.11 (i.e. actual BSA/ideal BSA). It is disappointing to find that, on average, females are 20 kilograms and males 18 kilograms above their ideal weight.

Table 1. Weight females (kg) Weight males (kg) BSA females (m2) BSA males (m2) Number. 16,160 14,376 16,160 14,376 Actual. 73.2 ± 18.9 89.1 ± 19.3 1.80 ± 0.24 2.08 ± 0.24 Ideal. 53.4 ± 6.5 71.4 ± 6.9 1.55 ± 0.13 1.87 ± 0.3 P value. <0.0001 <0.0001 <0.0001 <0.0001 BSA = Body surface area.

3042Gender differences in the prevalence of a normal IMT with increasing severity of carotid disease

Background

The ARIC group has shown that increasing IMT is only predictive of increased cardiovascular (CV) risk in males (M). Plaque is predictive of increased CV risk in both M and females (F).

Purpose

To determine the prevalence of a normal IMT (<1.00mm) in M and F with evidence of carotid plaque. Plaque score (PS) was used as a measure of severity of disease.

Methods

Our database was searched for patients with all the required data, IMT, PS and plaque area. IMT was measured with automatic edge detection software, PS was calculated using the Rotterdam method and plaque area was measured in the carotid bulb and ICA bilaterally. Only the first carotid study was used in the analysis. PS of 0–6 were used to estimate plaque severity. ANOVA and the Fisher's exact test were used to detect differences between groups. A p value of <0.05 was considered significant.

Results

There were 5981 patients, 3062 M and 2919 F with an average age of 62.1±11.3 years. Table I. indicates that with increasing PS, age, IMT and plaque area all increase, with a reciprocal decrease in the proportion of patients with a normal IMT. Of 3829 patients with carotid plaque 1355 (35.4%) had an IMT <1.00mm. There were clear gender differences with a much higher prevalence of a normal IMT in F with carotid plaque than M, 776 of 1772 (43.8%) versus 579 of 2057 (28.1%), p<0.0001, Fisher's exact test. This gender difference applies to most groups with increasing plaque burden except those with the most severe disease (PS “5–6”).

Table 1 PS “0” PS “1” PS “2” PS “3” PS “4” PS “5–6” N 2152 896 1209 792 562 370 ANOVA Age 57.6±12.2 60.4±9.2 63.0±9.5 66.5±9.3 67.8±8.9 71.5±8.8 <0.0001 IMT 0.94±0.32 1.00±0.23 1.08±0.29 1.30±0.55 1.51±0.75 2.77±0.88 <0.0001 Plaque area 0 16.5±11.6 35.1±20.0 58.6±29.9 91.0±43.1 130.4±61.3 <0.0001 Males 1005 424 627 422 331 253 IMT <1.00mm 671 222 226 77 50 4 Percentage 66.8% 52.4% 36.0% 18.2% 15.1% 1.6% Females 1147 472 582 370 231 117 IMT <1.00mm 879 293 288 136 57 2 Percentage 76.6% 62.1% 49.5% 36.8% 24.6% 1.7% Fisher's test <0.0001 <0.005 <0.0001 <0.0001 <0.0001 NS PS = Carotid ÷ 6 segments, assigned “0” or “1” if plaque is absent or present.

Conclusions

Significantly more women with carotid plaque have a normal IMT. This may explain why IMT fails to be predictive of CV risk in women.