Total Vascular Resistance Index Research Articles

VARIATION IN MEAN ARTERIAL PRESSURE AND ITS HEMODYNAMIC COMPONENTS DURING 24-HOUR AMBULATORY PULSE WAVE ANALYSIS: IMPACT OF AGE, RACE, AND GENDER

Objective: Blood pressure (BP) is highly variable but the concomitant variations of the underlying hemodynamic components [heart rate (HR), stroke volume (SV), and total vascular resistance (TVR)] are not known. We postulated that covariance (cov) analysis of 24-hour ambulatory pulse wave analysis (PWA) could reveal relevant trends in hemodynamic variability (var) within and between-individuals. Design and method: Ambulatory BP with PWA (Mobil-O-Graph, IEM, Stolzberg, DE) was performed every 20 minutes for 24 hours. Mean arterial pressure (MAP) components were indexed to body surface area: MAP = HR*[SV index (SVI)]*[TVR index (TVRI)] and ln(MAP) = ln(HR) + ln(SVI) + ln(TVRI). For cov analysis, var[ln(MAP)] = cov[ln(HR), ln(MAP)] + cov[ln(SVI), ln(MAP)] + cov[ln(TVRI), ln(MAP)]. Contributions of hemodynamic components to var[ln(MAP)] were expressed as %; other associations were nalysed by correlation and t-test. Results: We studied a convenience sample of 152 people (49% women, 23% black). Data are mean(SD): # readings 57(11), age 59(16) years, BMI 29.9(6.5) kg/m2, systolic BP 135(18) and MAP 106(14) mmHg. Mean 24-hr values were: ln(MAP) 4.64 (0.13), ln(HR) 4.20 (0.15), ln(SVI) -3.32 (0.15), and ln(TVRI) 3.75 (0.18). Relative contributions to 24-hour varMAP were: varTVRI 54(36)%, varHR 33(38)%, and varSVI 13(40)%. The large SDs in these component contributions prompted further analysis: varTVRI correlated with 24-hr mean MAP (r = 0.24, p = 0.003) and was higher (>54%) in males (p = 0.03) and blacks (p = 0.04); varHR was inversely related to MAP (r = -0.26, p = 0.001), age (r = -0.29, p = 0.0003) and BMI (r = -0.17 p = 0.05) and was lower (<33%) in blacks (p = 0.008); varSVI correlated with age (r = 0.31, p < 0.0001) and BMI (r = 0.23, p = 0.005) and was higher (>13%) in women (p = 0.03). Conclusions: Covariance analysis can be used with 24-hr ambulatory PWA to analyze BP and hemodynamic variability in everyday life. Within-individual total varMAP is related to varTVR > varHR > varSV but between-individual factors also affect these trends, including greater influence of varTVR in males and blacks, varHR in younger people, and varSV in younger people and women. HR varies inversely with SV and SVR suggesting counter-regulation. Diagnostic subclassifications or treatment modifications for variation extremes [e.g. vasodilators (TVR), beta-blockers (HR), or diuretics (SV)] may be possible.

Maternal echocardiographic changes in twin pregnancies with and without pre-eclampsia.

Twin pregnancies are at increased risk of developing hypertensive disorders of pregnancy (HDP) compared with singleton pregnancies, resulting in a substantially higher rate of maternal and perinatal complications. The strain caused by twin pregnancy on the maternal cardiovascular system has not been studied extensively. The objective of this study was to evaluate the changes in maternal cardiac morphology and diastolic function in a cohort of women with normotensive and those with hypertensive twin pregnancies. This was a cross-sectional study conducted at a tertiary referral university center. Women with singleton or twin pregnancy were enrolled prospectively to undergo maternal transthoracic echocardiography throughout pregnancy. Multiples of the median (MoM) were calculated for each index using a reference group of uncomplicated singleton pregnancies (n = 411) in order to adjust for changes associated with gestational age. Cardiac findings were indexed for body surface area and compared among normotensive twin pregnancies, singleton pregnancies complicated by HDP and twin pregnancies complicated by HDP. The total cohort included 119 HDP singleton pregnancies, 52 normotensive twin pregnancies and 24 HDP twin pregnancies. Left ventricular mass index (LVMi) MoM (median (interquartile range)) did not differ between singleton pregnancies complicated by HDP and normotensive twin pregnancies, but was significantly higher in HDP twin compared with HDP singleton pregnancies (1.31 (1.08-1.53) vs 1.17 (0.98-1.35), P = 0.032). Two diastolic indices, left atrial volume index MoM (1.12 (0.66-1.38) vs 0.65 (0.55-0.84), P = 0.003) and E/e' MoM (1.29 (1.09-1.54) vs 0.99 (0.99-1.02), P = 0.036), were significantly higher in HDP twin compared with normotensive twin pregnancies. In normotensive twin compared with HDP singleton pregnancies, stroke volume index (SVi) MoM was higher (1.20 (1.03-1.36) vs 1.00 (0.81-1.15), P = 0.004) and total vascular resistance index (TVRi) was lower (0.73 (0.70-0.86) vs 1.29 (1.04-1.56), P < 0.0001). In contrast, SVi MoM was lower (1.10 (1.02-1.35) vs 1.20 (1.03-1.36), P = 0.018) and TVRi was higher (1.00 (0.88-1.31) vs 0.73 (0.70-0.86), P = 0.029) in HDP twin compared with normotensive twin pregnancies. The maternal cardiovascular system is altered severely in twin pregnancy with or without HDP. Despite the low total vascular resistance, cardiac changes in normotensive twin pregnancies are comparable to those seen in singleton pregnancies complicated by HDP, reflecting the high cardiovascular demand imposed by twin pregnancy. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Maternal cardiovascular dysfunction in women with early onset preeclampsia: a cross-sectional study

Background Cardiac remodeling and diastolic dysfunction may occur, in women with early-onset preeclampsia, following raised total vascular resistance in response to the impaired placentation. These changes can increase the risk of premature cardiac morbidity and mortality later in life. According to updated guidelines by the American and European Societies of Echocardiography (ASE/ESE) to diagnose diastolic dysfunction, using a simpler criterion is not yet used in pregnant women. Objective To compare the maternal cardiovascular changes and the variation in the diastolic dysfunction using the 2009 and 2016 criteria by ASE/ESE among women with early onset preeclampsia and gestational age-matched normotensive controls. Methods A prospective matched cross-sectional study conducted in a tertiary hospital in South India, involving 40 women with early and 40 women with gestational age-matched normotensive controls. Cardiac function and remodeling were assessed by conventional 2D, M-mode, and Doppler echocardiography. Results Compared to the controls, women with early-onset preeclampsia had significantly higher. Total vascular resistance index (2867.6 vs. 2277.2 dynes/s/cm5/m2, p = .035) and median end-systolic stress index (5.2 vs. 9.2 dyne/cm2/m2), suggesting a higher afterload. Cases had a significant rate of left ventricular diastolic dysfunction using the 2009 criteria (grade II/III: 21 (52%) vs. 0 (0%), p<.001) whereas the rates were much lower when the updated 2016 guidelines were used (grade II/III: 9 (22.5%) vs. 1 (2.5%), p<.001). Conclusions In women with early-onset preeclampsia, cardiovascular adaption occurs to minimize wall stress and myocardial oxygenation. The prevalence of diastolic dysfunction was observed to be lower with the 2016 criteria. Further studies involving pregnant women are required to assess the impact of newer guidelines on association with short- and long-term cardiovascular outcomes in high-risk women.

Abstract P116: VARIATION IN MEAN ARTERIAL PRESSURE (MAP) AND ITS HEMODYNAMIC COMPONENTS DURING 24-HOUR AMBULATORY PULSE WAVE ANALYSIS: IMPACT OF AGE, RACE, GENDER AND BODY SIZE

BP is highly variable within and between individuals but the impact of variation in underlying hemodynamic components is unknown. We tested the feasibility and clinical associations of quantitated variances in MAP and its hemodynamic components [heart rate (HR), stroke volume (SV) and total vascular resistance (TVR)] obtained by 24-hr ambulatory pulse wave analysis (PWA, Mobil-O-Graph, IEM, Stolzberg, DE). BP and PWA were measured every 20 min for 24 hrs. Indexed to body surface area, MAP = HR*[SV index (SVI)]*[TVR index (TVRI)]; ln(MAP) = ln(HR) + ln(SVI) + ln(TVRI); and total MAP variability = var [ln(MAP)] = covariance (cov)[ln(HR), ln(MAP)] + cov[ln(SVI), ln(MAP)] + cov[ln(TVRI), ln(MAP)]. Relative contributions to var[ln(MAP)] for each hemodynamic component (as %) were calculated and associations with demographic characteristics were analyzed by correlations and t-tests. We studied 152 people (49% women, 23% black); mean(SD): # readings 57(11), age 59(16) yr, BMI 29.9(6.5) kg/m 2 , systolic BP 135(18) and MAP 106(14) mmHg. Mean(SD) 24-hr values were: ln(MAP) 4.64 (0.13), ln(HR) 4.20 (0.15), ln(SVI) -3.32 (0.15), and ln(TVRI) 3.75 (0.18). Relative contributions of hemodynamic components to total 24-hr ln(MAP) variation were: TVRI 54(36)%, HR 33(38)%, and SVI 13(40)%. The large SDs of these relative contributions led to analysis of potential contributing factors: TVRI contribution was correlated with 24-hr mean MAP (r=0.24, p=0.003) and was higher (&gt;54%) in males (p=0.03) and blacks (p=0.04); HR contribution was inversely related to MAP (r=-0.26, p=0.001), age (r=-0.29, p=0.0003) and BMI (r=-0.173 p=0.05) and was lower (&lt;33%) in blacks (p=0.008); SVI contribution was correlated with age (r=0.31, p&lt;0.0001) and BMI (r=0.23, p=0.005) and was higher (&gt;13%) in women (p=0.03). We conclude that 24-hr ambulatory PWA can identify components of MAP variation within individuals and their associations with demographic factors. The relative contributions of hemodynamic components (HR, SV, TVR) to 24-hr variability in ln(MAP) varies systematically with 24-hr mean MAP, age, race, gender, and BMI. Theoretical clinical implications may include therapeutic adjustments for extremes of variation in HR (beta-blockers), TVR (vasodilators) or SV (diuretics).

Abstract P177: The Dissociation of Heart Rate and Blood Pressure Masks the Regulatory Role of Heart Rate in Systemic Hemodynamics

Blood pressure (BP) and heart rate (HR) are independent cardiovascular risk factors but there is little information about interactions among HR, BP, and systemic hemodynamics throughout the day. We performed 24-hour ambulatory pulse wave analysis (Mobil-O-Graph, IEM, Stolberg, DE) with measurements at 20 minute intervals. Variables measured were: systolic and diastolic BP (SBP and DBP), HR, oscillometric pulse wave velocity (oPWV), stroke volume index (SVI), and total vascular resistance index (TVRI). We also performed regression analyses within-subjects to determine the slopes of the SVI-HR and TVRI-HR relationships within individuals and for the group. We studied 89 individuals (mean age 61 years, weight 84 kg, BP 138/82 mm Hg (38 normal or controlled BP, 51 uncontrolled BP), resting HR 69 beats/min (bpm), 36% non-white, 64% female); 24-hour mean HR was not correlated with corresponding SBP or DBP values (r= -0.013 and r= 0.154, pNS, respectively) and this dissociation persisted in corresponding day-time vs. night-time comparisons and subgroup stratification by BP control status, age, and gender. In contrast, 24-hour mean HR was strongly correlated with 24-hour mean cardiac index (r=0.629, p&lt;0.000) but strongly inversely related to mean 24-hour SVI and TVRI (r= -0.508 and r= -0.505, p&lt;0.000 each); each 10 beat/min change in mean HR was associated with a 2.3 mL/m 2 (6%) change in SVI and a corresponding 6% change in TVRI. Analysis of individual 24-hour studies also revealed no correlations between HR and BP but the within-individual slopes and correlation coefficients between HR and SVI or TVRI were more variable; higher oPWV (which correlated with the SD of SBP, p=.01) was associated with a lesser sensitivity of SVI to HR change and a greater sensitivity of TVRI to HR change (p&lt;0.001 each) independent of age, gender, or BP. We conclude that BP is normally independent of HR, which plays a hidden but important regulatory role in the underlying systemic hemodynamics between and within individuals. The clinical impact of differential sensitivity of systemic hemodynamics to HR change is not established but people with stiffer arteries display diminished SVI sensitivity and greater TVRI sensitivity to HR change, which may contribute to their greater SBP variability.

The Role of Muscle Metaboreflex in the Reduced Blood Pressure Response to Exercise in Patients Living with HIV

The cardiovascular adjustments during exercise are regulated by several neural mechanisms working in concert, including the muscle metaboreflex. The response to this reflex could be involved in the reduced diastolic blood pressure observed in HIV patients during exercise. However, this hypothesis has not been tested yet. Thus, 18 patients living with HIV (46±10 yr, mean ±SD; 16 men; HIV group) and 13 control subjects (41±8 yr; 10 men; Control group) were evaluated. Systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), cardiac output and total vascular resistance were calculated using photoplethysmography and Model flow method. Cardiac index (CI) and total vascular resistance index (TVRI) were corrected by body surface area. SBP and DBP was recorded during 3 minutes of rest, followed by 3 minutes of isometric handgrip exercise at 30% of their maximal voluntary force and 2 minutes of post exercise ischemia to isolate muscle metaboreflex activation. Data were subject to two‐way ANOVA followed by multiple comparisons with Bonferroni correction. SBP increased during exercise (Control: Δ22±6 mmHg vs. HIV: Δ17±8 mmHg) and during metaboreflex activation in both groups (1st min: Control: Δ12±6 mmHg vs. HIV: Δ8±5 mmHg; 2nd min: Control: Δ15±8 mmHg vs. HIV: Δ12±9 mmHg). However, DBP response to exercise was attenuated in HIV patients (Control: Δ16±5 mmHg vs. HIV: Δ10±4 mmHg). This difference remained during metaboreflex activation (1st min: Control: Δ9±5 mmHg vs. HIV: Δ3±2 mmHg; 2nd min: Control: Δ11±6 mmHg vs. HIV: Δ6±4 mmHg). TVRI increased during exercise only in the control group (Control: Δ1.31±0.79 mmHg.min/l vs. HIV: Δ0.28±1.60 mmHg.min/l) and remained elevated during metaboreflex activation. In contrast, a decrease of the TVRI during the 1st minute of the metaboreflex activation (Control: Δ1.43±0.69 mmHg.min/l vs. HIV: Δ0.22±1.22 mmHg.min/l) and a blunted increase at the 2nd minute was observed in HIV patients (Control: Δ1.56±1.04 mmHg.min/l vs. HIV: Δ0.84±1.25 mmHg.min/l). CI increased during exercise (Control: Δ0.43±0.57 l/min vs. HIV: Δ0.42±0.32 l/min) and decreased during metaboreflex activation in both groups (1st min: Control: Δ0.07±0.32 l/min vs. HIV: Δ0.15±0.25 l/min; 2nd min: Control: Δ0.16±0.42 l/min vs. HIV: Δ 0.13±0.25 l/min). HR increased during exercise (Control: Δ9±6 bpm vs. HIV: Δ8±4 bpm) and returned to resting values during metaboreflex activation in both groups (1st min: Control: Δ‐1±2 bpm vs. HIV: Δ0±3 bpm; 2nd min: Control: Δ0±3 bpm vs. HIV: Δ0±4 bpm). In conclusion, seems that patients living with HIV present blunted peripheral vasoconstriction response to metaboreflex activation, which explain the reduced diastolic blood pressure response to exercise, already observed in these patients. We believe that a lower sympathetic activation and/or deficient sympathetic vascular transduction are the two possible mechanisms driving the response.Support or Funding InformationFAPERJ, CAPES and CNPqThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effects of β2 Adrenergic Receptor on Coronary Blood Flow and Cardiovascular Responses during Exercise and Metaboreflex in Men and Women

Redundant mechanisms modulate coronary blood flow (CBF) matched to the metabolic demand.However, the possible sex differences in the mechanisms of CBF control are not fully understood. In addition, the effect of skeletal muscle metaboreflex on CBF in humans is unclear. Thus, 9 men (26 ± 4 yr; 23 ± 2 kg/m2) and 7 women (24 ± 4 yr; 24 ± 3 kg/m2) had their heart rate (HR) and blood pressure recorded. Mean arterial pressure (MAP), cardiac index (CI), total vascular resistance index (TVRI), femoral blood flow (FBF) and myocardial oxygen consumption (MVO2) were estimated. CBF was calculated as average of maximal blood flow velocity on the diastolic phase of ten cardiac cycles. The protocol consisted in 3 minutes rest, 3 minutes of handgrip exercise at 40% of the maximal voluntary force, 3 minutes of peripheral circulatory occlusion (metaboreflex) and recovery, before and after β2‐AR blockade (propranolol). Effects were statistically tested by two‐way ANOVA in men and women, followed by multiple comparisons with Bonferroni correction. HR increased during exercise in men and women (MΔ24 ± 22 BPM; WΔ23 ± 10 BPM; mean ± SD), and the β2‐AR blockade blunted the increase (MΔ 10 ± 6 BPM; WΔ 13 ± 5 BPM). MAP increased during exercise (MΔ36 ± 5 mmHg; WΔ36 ± 11 mmHg); the β2‐AR blockade reduced MAP in men, with no effect on the response during exercise (MΔ36 ± 5 mmHg; WΔ36 ± 11 mmHg). MAP decreased during metaboreflex activation compared to exercise, but was increased compared to rest (M Δ26 ± 9 mmHg; W Δ22 ± 8 mmHg), and β2‐AR blockade did not change this effect. CI increased during exercise in men and women (MΔ0.96 ± 1.2 L.min.m2; WΔ1.5 ± 0.6 L.min.m2), which was blunted by β2‐AR blockade (MΔ0.5 ± 0.6 L.min.m2; WΔ0.8 ± 0.6 L.min.m2). Compared to rest, metaboreflex increased CI only in women (MΔ −0.01 ± 0.7 L.min.m2; WΔ0.88 ± 0.6 L.min.m2), the β2‐AR blockade did not change the CI. TVRI increased during exercise (MΔ0.96 ± 1.6 mmHg/11·min/m2; WΔ −0.18 ± 0.9 mmHg/11·min/m2) and metaboreflex activation (MΔ2.0 ± 1.5 mmHg/11·min/m2; WΔ −0.13 ± 0.8 mmHg/11·min/m2) only in men. With β2‐AR blockade TVRI increased in women during exercise (MΔ1.95 ± 1.4 mmHg/11·min/m2; WΔ1.26 ± 1.9 mmHg/11·min/m2) and metaboreflex (MΔ2.2 ± 1.5 mmHg/11·min/m2; WΔ0.5 ± 0.8 mmHg/11·min/m2). FBF increased during exercise (MΔ564 ± 706 ml/min1; WΔ 573 ± 438 ml/min1) and metaboreflex activation (MΔ74 ± 253 ml/min1; WΔ 280 ± 487 ml/min1) and β2‐AR blockade prevented the increase in both groups. CBF increased during exercise (MΔ11 ± 8 cm/s1; WΔ 6 ± 8 cm/s1) and metaboreflex activation (MΔ0.3 ± 2 cm/s1; WΔ −0.8 ± 3 cm/s1) in men; after β2‐AR blockade CBF did not change in either groups in both conditions. MVO2 increased during exercise (MΔ6.5 ± 3.6; WΔ 5.0 ± 2.0) and metaboreflex activation (MΔ3.2 ± 1.0; WΔ 3.0 ± 1.2) in men and women and β2‐AR blockade blunted the increase. β2‐AR seems to play an import role to the lower TVR observed in women in response to exercise and metaboreflex activation. The increase of CBF during exercise and metaboreflex was higher in men and the β2‐AR blockade prevented the increase.Support or Funding InformationCAPES, CNPQ, FAPERJ, National Institute for Science &amp; Technology ‐ INCT (In)activity &amp; ExerciseThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Maternal cardiovascular dysfunction in women with early onset preeclampsia and late onset preeclampsia: A cross-sectional study.

To compare the cardiovascular changes associated with early onset (EOPE) and late onset (LOPE) subtypes of preeclampsia. A prospective matched cross-sectional study involving 50 women each with early and late onset subtypes of preeclampsia conducted in a tertiary hospital in South India. Cardiac function and remodelling were assessed by conventional 2D, M-mode and doppler echocardiography. Women with EOPE had a significantly more altered left ventricular (LV) geometry, global LV diastolic dysfunction, impairment in myocardial contractility (40% vs. 24%) and a higher total vascular resistance index (863.0 vs 704.0 dynes/s/cm5/m2) compared to LOPE. Stroke volume index (55.3 vs. 62.2 ml/m2) and cardiac work index (520.7 vs. 584.9mmHg×L/min/m2) were higher in women with LOPE. However, the systolic function was found to be preserved in the LV in both the groups. Women with EOPE have a more severe cardiac impairment than those with LOPE. The difference in the hemodynamic indices may provide a chance to tailor patient-specific treatment strategies to improve the pregnancy outcome as well as in early identification and initiation of preventive measures for those at risk of cardiovascular diseases later in life. Adaptation of the heart in women with early onset subtype differs with that of late onset subtype of preeclampsia. Total vascular resistance is higher in early onset group compared to late onset group having a higher cardiac output. These differences in the hemodynamic indices may provide a chance to tailor patient-specific treatment strategies to improve the pregnancy outcome as well as in early identification and initiation of preventive measures for those at risk of cardiovascular diseases later in life.

OC12.01: Maternal cardiovascular impairment in preterm fetal growth restricted pregnancies

Fetal growth restriction and pre-eclampsia are both conditions of placental etiology and associated to increased risk for the long term development of cardiovascular disease in the mother. At presentation, pre-eclampsia is associated with maternal global diastolic dysfunction which is determined, at least in part, by increased afterload and myocardial stiffness. The aim of this study is to test the hypothesis that women with normotensive fetal growth restricted pregnancies also exhibit global diastolic dysfunction. This was a prospective case-control study conducted over a three year period involving 29 preterm fetal growth restricted, 25 preeclamptic with fetal growth restriction pregnancies and 58 matched control pregnancies. Women were assessed by conventional echocardiography and tissue Doppler imaging at diagnosis of the complication and followed-up at 12 weeks postpartum. Fetal growth restricted pregnancies are characterized by a lower cardiac index and higher total vascular resistance index than expected for gestation. Compared to controls, fetal growth restricted pregnancy was associated with significantly increased prevalence (P = 0.0001) of asymptomatic left ventricular diastolic dysfunction (28% versus 4%) and widespread impaired myocardial relaxation (59% versus 21%). Unlike pre-eclampsia, cardiac geometry and intrinsic myocardial contractility were preserved in fetal growth restricted pregnancy. Fetal growth restricted pregnancies are characterized by a low output, high resistance circulatory state as well as a higher prevalence of asymptomatic global diastolic dysfunction and poor cardiac reserve. These findings may explain the increased long-term cardiovascular risk in these women who have had fetal growth restricted pregnancies. Further studies are needed to clarify the postnatal natural history of cardiac dysfunction in these women.

Maternal Cardiovascular Impairment in Pregnancies Complicated by Severe Fetal Growth Restriction

Fetal growth restriction and preeclampsia are both conditions of placental etiology and associated to increased risk for the long-term development of cardiovascular disease in the mother. At presentation, preeclampsia is associated with maternal global diastolic dysfunction, which is determined, at least in part, by increased afterload and myocardial stiffness. The aim of this study is to test the hypothesis that women with normotensive fetal growth-restricted pregnancies also exhibit global diastolic dysfunction. This was a prospective case-control study conducted over a 3-year period involving 29 preterm fetal growth-restricted pregnancies, 25 preeclamptic with fetal growth restriction pregnancies, and 58 matched control pregnancies. Women were assessed by conventional echocardiography and tissue Doppler imaging at diagnosis of the complication and followed-up at 12 weeks postpartum. Fetal growth-restricted pregnancies are characterized by a lower cardiac index and higher total vascular resistance index than expected for gestation. Compared with controls, fetal growth-restricted pregnancy was associated with significantly increased prevalence (P<0.001) of asymptomatic left ventricular diastolic dysfunction (28% versus 4%) and widespread impaired myocardial relaxation (59% versus 21%). Unlike preeclampsia, cardiac geometry and intrinsic myocardial contractility were preserved in fetal growth-restricted pregnancy. Fetal growth-restricted pregnancies are characterized by a low output, high resistance circulatory state, as well as a higher prevalence of asymptomatic global diastolic dysfunction and poor cardiac reserve. These findings may explain the increased long-term cardiovascular risk in these women who have had fetal growth-restricted pregnancies. Further studies are needed to clarify the postnatal natural history of cardiac dysfunction in these women.

Impact of Arterial Load on Left Ventricular Diastolic Function in Patients Undergoing Cardiac Catheterization for Coronary Artery Disease

Although left ventricular (LV) diastolic dysfunction is associated with increased risk for incident heart failure in patients with coronary artery disease (CAD), no specific treatment for diastolic abnormalities has been established. Animal and small human studies have shown that an acute increase in LV afterload adversely impacts on LV early diastolic relaxation, but little is known about its chronic effect on diastolic function. The relationships of various components of arterial load (arterial compliance, total vascular resistance index, and augmentation index [AI] in the ascending aorta) with LV diastolic function indices determined on cardiac catheterization (relaxation time constant [Tau] and end-diastolic pressure [EDP]) and those on tissue Doppler echocardiography (early diastolic mitral annular velocity [E'] and the ratio of early diastolic mitral inflow to annular velocities [E/E']) were investigated in 303 consecutive patients undergoing cardiac catheterization for CAD. All components of arterial load correlated with diastolic function indices, with AI, an index reflecting late-systolic load, having the strongest correlations with diastolic function indices. After adjustment for potential confounders, AI correlated with Tau (standardized beta=0.25, P<0.001), EDP (beta=0.25, P<0.001), E' (beta=-0.21, P<0.001), and E/E' (beta=0.23, P<0.001). Increased AI is independently associated with LV diastolic function in patients with known or suspected CAD. Late-systolic load may be a therapeutic target to improve LV diastolic abnormalities in this population.

Hemodynamic benefits of long-term bunazosin(alpha-1 blocker) therapy in rats with myocardial infarction and heart failure.

To determine whether bunazosin (alpha 1-adrenoceptor blocking agent) can alter the hemodynamic profile of chronic heart failure secondary to myocardial infarction, the drug was administered to Wistar rats 4 weeks after coronary ligation, and continued for 4 weeks. In rats without bunazosin treatment, the left ventricular end-diastolic pressure (LVEDP) and the total vascular resistance index (TVRI) increased as a function of infarct size, while the cardiac index (CI) decreased. But in infarcted rats with bunazosin treatment, the mean aortic pressure and TVRI were reduced, the LVEDP was modestly lessened, and the CI was maintained. The greatest increase in CI after the treatment occurred in rats with infarcts of small and moderate size. Thus, long-term therapy with bunazosin improved LV dysfunction, relative to the size of infarction. This study suggests the beneficial effects of bunazosin therapy in patients with chronic heart failure.