Characterizing left ventricular stiffness in women with signs and symptoms of ischemia with no obstructive coronary arteries

Background

Women with signs and symptoms of ischemia and no obstructive coronary arteries (INOCA) have evidence of diastolic dysfunction and are at increased risk of developing heart failure with preserved ejection fraction (HFpEF). However, mechanisms contributing to HFpEF development are poorly understood and often attributed to underlying cardiovascular risk factors.

Purpose

To compare clinical, invasive, and imaging parameters in women with suspected INOCA and various degrees of left ventricular (LV) stiffness (as measured by invasive end-diastolic pressure [EDP]/end diastolic volume [EDV]).

Methods

Women with suspected INOCA underwent invasive LV pressure-volume loop analysis at rest and coronary function testing with a Doppler wire in the left anterior descending artery. Intracoronary vasoactive substances (adenosine, acetylcholine, nitroglycerin) were infused into the left main artery, as published. Rest and adenosine stress cardiac magnetic resonance (CMR) imaging was performed to evaluate LV function, structure, perfusion, and fibrosis. Women in different tertiles of EDP/EDV ratio were compared using t-tests.

Results

A total of 62 women with complete invasive data were included; 2 did not complete CMR. Compared to the lower EDP/EDV tertile, women in the upper tertile were older, had higher ejection fraction, higher mass/volume ratio, worse diastolic function, greater aortic stiffness and worse coronary microvascular function (Table 1). Traditional cardiovascular risk factors were not significantly different.

Conclusion

Among women with INOCA, older age, coronary microvascular dysfunction, and aortic stiffness were related to greater LV stiffness at rest. Those with the highest EDP/EDV ratio had hyperdynamic LV systolic function and the smallest LV size. More work is needed to understand contribution of coronary microvascular dysfunction to HFpEF progression.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): National Institutes of HealthErika Glazer Women's Heart Health Project

Ventricular and vascular stiffening in ischemia with no obstructed coronary arteries: novel insight from pressure-volume analysis

Background

Ischemia with no obstructed coronary arteries (INOCA) is prevalent among women and associated with an increased risk of developing heart failure with preserved ejection fraction (HFpEF), however the mechanism linking these conditions remains poorly understood. Coronary vascular dysfunction is common in INOCA, representing a putative mechanism driving heart failure progression.

Purpose

To evaluate the role of coronary vascular dysfunction on left ventricular (LV) function in women with INOCA.

Methods

Women with suspected INOCA, defined as having signs and symptoms of ischemia but no obstructive coronary artery disease, underwent LV pressure-volume assessment at rest and during 3 minutes of isometric handgrip stress at 30% of maximal voluntary contraction. Coronary function testing was performed by infusing standard doses of adenosine, acetylcholine, and nitroglycerine through a guiding catheter placed in the left main coronary artery, per our published protocols. Using standardized definitions of normal versus abnormal responses, cases with zero abnormal coronary pathways (n=12) were compared to cases with three abnormal coronary pathways (n=7).

Results

At rest, end-systolic pressure and end-systolic elastance were elevated in cases with abnormal coronary vascular function (Figure), while normalized peak filling rate was lower (0.45±0.15 s mmHg–1 vs 0.37±0.08 s mmHg–1). With isometric handgrip, end-systolic pressure and end-systolic elastance increased similarly between groups, remaining highest in those with abnormal coronary vascular function (Figure). End-diastolic pressure-volume declined with handgrip in those without coronary vascular dysfunction, while increasing (up and to the left) in those with coronary vascular dysfunction (Figure). Likewise, normalized peak filling rate improved with handgrip in those without coronary vascular dysfunction, but did not change in those with coronary vascular dysfunction (0.66±0.37 s mmHg–1 vs 0.38±0.15 s mmHg–1).

Conclusions

We show heightened ventricular and vascular stiffness in women with INOCA who have abnormal coronary vascular function. These preliminary data support the hypothesis that coronary vascular dysfunction may be a putative mechanistic pathway driving heart failure progression in INOCA.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Institutes of Health

Cold Pressor Testing and Sympathetic Nervous System Contribution to Ischemia with No Obstructive Coronary Artery Disease: Results from the Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction Project

Study Objective

Cold Pressor Testing (CPT) is a known stimulus of the sympathetic nervous system (SNS). To better understand sympathetic contribution to coronary blood flow regulation in women with suspected ischemia and no obstructive coronary arteries (INOCA), we compared myocardial perfusion reserve during CPT stress cardiac magnetic resonance (CMR) imaging between women with suspected INOCA and reference subjects.

Design

Prospective cohort.

Setting

Academic hospital.

Participants

107 women with suspected INOCA and 21-age-matched reference women.

Interventions

CPT stress CMR was performed with measurement of myocardial perfusion reserve index (MPRI), adjusted for rate pressure product (MPRI_RPP). Invasive coronary function testing in a subset of INOCA women (n=42) evaluated for endothelial dysfunction in response to acetylcholine, including impaired coronary diameter response ≤0% and coronary blood flow response (ΔCBF) <50%.

Main Outcome Measure

MPRI_RPP.

Results

Compared to reference women, the INOCA group demonstrated higher resting RPP (p=0.005) and CPT MPRI_RPP (1.09±0.36 vs 0.83±0.18, p=0.002). Furthermore, INOCA women with impaired ΔCBF (n=23) had higher CPT MPRI_RPP (p=0.044) compared to reference women despite lower left ventricular ejection fraction (64±7 % vs 69±2 %, p=0.005) and mass-to-volume ratio (0.79±0.15 vs 0.62±0.09, p<0.0001). These differences in CPT MPRI_RPP did not persist after adjusting for age, body mass index, and history of hypertension. CPT MPRI_RPP among INOCA women did not differ based on defined acetylcholine responses.

Conclusions

Myocardial perfusion reserve to CPT stress is greater among women with INOCA compared to reference subjects. CPT induced a higher MPRI_RPP also in women with coronary endothelial dysfunction, suggesting a greater contribution of the SNS to coronary flow than endothelial dysfunction. Further investigation in a larger cohort is needed.

Abnormal left ventricular geometry in female collegiate swimmers

Background

There is a paucity of data describing left ventricular geometry changes in female athletes. While some studies suggest that female athletes participating in dynamic sports exhibit higher prevalence of eccentric left ventricular hypertrophy (LVH) when compared to men, a recent study suggested more concentric geometry changes in female basketball athletes. We were unable to identify studies describing the left ventricular geometry of female collegiate swimmers.

Objectives

To describe LV geometry changes in a cohort of female collegiate swimmers.

Methods

We analyzed a cohort of female collegiate swimmers who had a pre-participation cardiac evaluation by 12-lead ECG and 2-dimensional echocardiography. Left ventricular (LV) geometry was assessed based on relative wall thickness (RWT) (defined as: 2 x posterior wall thickness (PWT) divided by LV end-diastolic diameter (LVEDD)) and LV mass (LVM) (Devereux's formula: LVM = [0.8 x 1.04 [(LVEDD + interventricular septum + posterior wall thickness)3 − (LVEDD)3]] + 0.6g) and was indexed to body surface area (BSA).LVH was defined as LV mass index &gt;95 g and was defined as concentric when associated with a relative wall thickness (RWT) &gt;0.42 and as eccentric when RWT was ≤0.42. Concentric remodeling was defined as normal LVM index and increased RWT.

Results

A total of 83 female collegiate swimmers were included. Their age was 18.5±0.5 years (mean ± standard deviation, SD), 74 (89.2%) were White, BSA was 1.78±0.11 m2, height 173±6.3 cm, weight 66.2±7.2 K. Their interventricular septum diameter was 0.89±0.14 cm, PWT 0.92±0.15 cm, LVEDD 4.9±0.5 cm and LV end-systolic diameter (LVESD) 3.2±0.4 cm. Left atrium diameter ranged from 2.6 to 4.3 cm (mean 3.4 cm ± 0.4 cm). Aortic root diameter ranged from 1.9 to 3.5 cm (mean 2.7±0.3 cm) (Figure 1). LVH was present in 27 swimmers (32.5%). Eccentric LVH was present in 17 athletes (20.5%), concentric hypertrophy in 10 athletes (12%), and concentric remodeling in 12 (14.5%) (Figure 2). No athletes with LVH or concentric remodeling had borderline or abnormal ECG findings based on international criteria. Only two women with normal LV geometry had abnormal ECG findings: prolonged QT interval and abnormal T wave inversion. There was a linear correlation between BSA with LVEDD, LVESD and LV mass (r=0.40, 0.35, and 0.48 with P&lt;0.001,0.002 and &lt;0.001, respectively). However, there was no statistically significant difference between LV geometry groups based on BSA or blood pressure.

Conclusion

Our data document a high incidence of eccentric hypertrophy among female collegiate swimmers. Concentric remodeling and hypertrophy were also relatively high. Differentiating physiologic from pathologic cardiac remodeling in these athletes is critical to prevent potential complications such as sudden cardiac death, arrhythmias, and other adverse outcomes.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): This work was supported in part by the American Medical Society for Sports Medicine (AMSSM) Foundation Research Grant 2016 awarded to KE, and the University of Florida REDCap uses the NIH National Center for Advancing Translational Sciences (NCATS) grant UL1 TR001427. Figure 1Figure 2. LV geometry in female swimmers

Prognostic significance of anemia in women with suspected ischemia, an insight from the women ischemia syndrome evaluation study (WISE)

Background

Anemia is associated with adverse cardiovascular outcomes in patients with myocardial infarction and congestive heart failure. Anemia is more prevalent in women. We investigated the prognosis of anemia in women with suspected ischemic heart disease.

Purpose

To study if hemoglobin levels at baseline in women with symptoms of ischemia predicts long term all-cause mortality and major adverse cardiac events.

Methods

We studied 885 women enrolled in WISE (1997–2001) undergoing clinically indicated coronary angiography for suspected ischemia. Anemia was defined as hemoglobin (Hb) level &lt;12g/dL. Major adverse cardiovascular event (MACE) included all-cause death, nonfatal myocardial infarction, stroke and heart failure hospitalization. Cox regression models and Kaplan-Meier methods were was used.

Results

Overall, 885 women, mean age 58.4±11.7 years, 21.1% and anemia were followed for 6.8 years. Anemic women had higher creatinine, history of diabetes mellitus, hypertension and CHF (p&lt;0.05), but not obstructive coronary artery disease compared to non-anemia women (p=0.97). Anemic women had higher all-cause mortality and MACE (Figure). In multivariate analysis, anemia was independently associated with increased MACE risk (hazard ratio (HR): 1.5, 95% confidence interval [1.11- 2.01, p=0.007]) but not all-cause mortality (HR: 1.2 [0.84–1.72, p=0.30]).

Conclusions

Among women evaluated for symptoms of ischemia, anemia is associated with and independently predicts MACE. Further research targeting anemia treatment in women to mitigate these adverse outcomes is warranted.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): NIH USA

P5730Do hypertensive women with coronary artery disease benefit from lowering systolic blood pressure under 130 mmHg? Long-term mortality in the INternational VErapamil SR-trandolapril STudy (INVEST)

Background

Hypertension (HTN) and coronary artery disease (CAD) are a prevalent combination in women, however limited data are available to guide blood pressure (BP) management. We hypothesize older women with HTN and CAD may not derive the same prognostic benefit from systolic BP (SBP) lowering <130 mmHg.

Purpose

To investigate the long-term mortality implications of different achieved SBP levels in hypertensive women with CAD.

Methods

Long-term, all-cause mortality data were analyzed for 9216 women, stratified by risk attributable to clinical severity of CAD (women with prior myocardial infarction or revascularization considered at high, all others at low risk) and by age (50 - <65 or ≥65 yo). The prognostic impact of achieving mean in-trial SBP <130 (referent group) was compared with 130 to <140 and ≥140 mmHg using Cox proportional hazards, adjusting for demographic and clinical characteristics.

Results

During 108,838 person-years of follow-up, 2945 deaths occurred. High risk women (n=3011) had increased long-term mortality in comparison to low risk women (n=6205) (adjusted HR 1.38, CI 1.28–1.5, p<0.001). Within risk groups, crude mortality percentages decreased according to BP values (table). As expected, high risk women were more likely to be ≥65 yo (68.68% vs. 50.51%, p<0.0001) or have SBP ≥140 mmHg (43.08% vs. 31.18%, p<0.0001). In adjusted analyses, an SBP ≥140 mmHg was associated with worse outcomes than SBP <130 mmHg in the entire cohort (HR 1.3, CI 1.2–1.5, p<0.0001) and when stratifying by risk (low risk group, HR = 1.47, CI 1.28–1.7, p<0.0001; high risk group, HR = 1.71, CI 1.01–1.35, p=0.03). In analyses stratified by age and risk, women ≥65 years and at high risk had decreased mortality in the 130 - <140 SBP category vs. <130 mmHg (HR 0.812, 95% CI 0.689–0.957, p=0.0133; figure).

Women and deaths by risk and SBP group Group SBP category Women (n) Mortality (n) Mortality (%) High risk <130 773 338 44 130–<140 941 414 44 ≥140 1297 694 54 Low risk <130 2187 390 18 130–<140 2083 451 22 ≥140 1935 658 34 SBP = systolic blood pressure; n = number; % = percent per each group.

Mortality adjusted HRs

Conclusion

In women ≥65 yo with hypertension and prior myocardial infarction and/or coronary revascularization enrolled in INVEST, a SBP between 130 to <140 mmHg was associated with lower all-cause, long-term mortality versus SBP <130 mmHg.

Acknowledgement/Funding

The main INVEST (International Verapamil [SR]/Trandolapril Study) was funded by grants from BASF Pharma, Ludwigshafen, Germany; Abbott Laboratories, A

Genome-wide association study identifies pharmacogenomic loci linked with specific antihypertensive drug treatment and new-onset diabetes

We conducted a discovery genome-wide association study with expression quantitative trait loci (eQTL) annotation of new-onset diabetes (NOD) among European Americans, who were exposed to a calcium channel blocker-based strategy (CCB strategy) or a β-blocker-based strategy (β-blocker strategy) in the INternational VErapamil SR Trandolapril STudy. Replication of the top signal from the SNP*treatment interaction analysis was attempted in Hispanic and African Americans, and a joint meta-analysis was performed (total 334 NOD cases and 806 matched controls). PLEKHH2 rs11124945 at 2p21 interacted with antihypertensive exposure for NOD (meta-analysis p=5.3×10⁻⁸). rs11124945 G allele carriers had lower odds for NOD when exposed to the β-blocker strategy compared with the CCB strategy [OR=0.38 (0.24-0.60), p=4.0×10⁻⁵], while A/A homozygotes exposed to the β-blocker strategy had increased odds for NOD compared with the CCB strategy [OR=2.02 (1.39-2.92), p=2.0×10⁻⁴]. eQTL annotation of the 2p21 locus provides functional support for regulating gene expression.

Angiographic definition of critical coronary artery stenosis

In summary, it is hazardous to rely solely on coronary angiography to define critical coronary stenosis. Clinically, the physiologic significance of a narrowing observed at coronary angiography can best be evaluated by obtaining additional evidence of myocardial ischemia, i.e. stress testing with ECG monitoring, resting and exercise isotope perfusion studies or ventriculographic studies. However, when evaluating coronary angiograms for critical coronary stenosis, several points are worth considering. First, a long narrowing will decrease coronary blood flow more than a short narrowing of the same severity. Second, sequential narrowings will decrease coronary blood flow more than a single narrowing of the same total length. Third, a long narrowing can be estimated more accurately than a short narrowing. Fourth, caliper measurements of coronary artery narrowings are more accurate than subjective estimation, and fifth, coronary artery dilators may increase the percentage narrowing in some cases. The complex effects of percent stenosis and length of stenosis on the physiology of coronary blood flow must always be considered when evaluating angiograms. In addition, the angiographic or photographic artifacts produced by short narrowings tend to overestimate the percent stenosis and, thus, calipers should be used to measure percent stenosis, especially in the short narrowings.

Use of vasodilators in congestive heart failure

In order to select the proper vasodilator agent for the treatment of congestive heart failure, the underlying etiology and pathophysiology of heart failure must be understood since they are important determinants of the response to the particular vasodilator being used. Short-term studies are impressive. Most patients respond dramatically to vasodilators. Long-term studies are not available at this time. When they become available, the clinical usefulness of this group of drugs will be put in proper perspective.

The vascular biology of hypertension and atherosclerosis and intervention with calcium antagonists and angiotensin-converting enzyme inhibitors

Recent advances in the understanding of vascular disease genesis suggest that atherosclerosis and hypertension, primary targets of therapy in the INternational VErapamil SR/trandolapril STudy (INVEST), are closely related. A unified model for the development of cardiovascular disease (CVD) is emerging from recent advances related to atherosclerosis and hypertension. The process of vascular disease appears to begin early in life, when signs of endothelial dysfunction first appear. A primary cause of CVD progression is increased oxidative stress in the endothelium caused by multiple risk factor conditions, including heredity, dyslipidemia, smoking, diabetes, and elevated systolic blood pressure (SBP > 110 mmHg). The renin-angiotensin and kallikrein-kinin systems are important regulators of blood pressure and atherosclerosis. In the renin-angiotensin system, angiotensin-converting enzyme (ACE) mediates generation of angiotensin II (ang II) at local vascular sites and in the plasma and also degrades bradykinin. Information derived from INVEST will help to identify treatment strategies, such as those containing a calcium antagonist and an ACE inhibitor, that are targeted directly at the vascular disorder responsible for hypertension and atherosclerosis.

Enhancing clinical trials on the internet: lessons from INVEST

The INternational VErapamil SR/trandolapril STudy (INVEST) is the first long-term, large-scale clinical trial being conducted primarily using Web-based technology. The Web is a powerful tool for enhancing clinical trial management because of its ability to centralize all study information and coordinate multiple trial processes in real time at lower cost. The result is improved efficiency, accuracy, and safety in clinical trials conduct. In Web-based clinical trials, sites are able to focus primarily on medicine and science, rather than on trial administration. Site training, study documentation, subject recruitment, randomization, medication dispensing, and management procedures are simplified by using Web-based software to enhance processes. This paper summarizes the advantages achieved for INVEST investigators, sponsor representatives, monitors, and subjects resulting from the centralization and coordination of multiple tasks through Web-based technology.

Digital assessment of the epicardial electrocardiogram: novel methodology for a core laboratory for clinical studies

BACKGROUND

The epicardial electrocardiogram (ECG) is a sensitive marker for cardiac ischemia and has been used as a measure of ischemia in clinical trials. We sought to examine the utility of a central ECG laboratory for determining ischemic-type ST-segment shifts from epicardial ECG recordings obtained from multiple clinical sites.

HYPOTHESIS

We speculated that an operator-assisted digital ECG core laboratory is feasible, reliable, and efficient, with the ability for rapid and accurate interpretation of the epicardial ECG.

METHODS

The epicardial ECG was recorded via an angioplasty guidewire placed in a coronary artery of a patient undergoing angioplasty. Site investigators visually determined the time-to-onset of 0.1 and 0.3 mm ST-segment elevation, and the maximal ST-segment elevation during balloon inflation, and then compared the measurements with those made at an operator-assisted digital ECG core laboratory.

RESULTS

Agreement between the two methods occurred in 78% of the time-to-onset measurements, but in only 39% of the maximal ST-segment measurements. Overall, the visual measurements of the clinical investigators of time-to-onset differed from the digital core laboratory by 11.8 +/- 11.6 s for 0.1 mV, and 15.8 +/- 20.6 s for 0.3 mV. Recorded maximal ST-segment shifts differed by a mean of 0.47 +/- 0.69 mV.

CONCLUSION

The magnitude of inconsistency between the ECG core laboratory results using an operator-assisted digital method and the interpretations of clinical investigators using manual caliper-type analysis was surprisingly large. These results support the need for an ECG core laboratory in clinical trials where ECG ST-segment shifts are used as a response variable.

Clinical and detailed angiographic findings in patients with ambulatory electrocardiographic ischemia without critical coronary narrowing: results from the Asymptomatic Cardiac Ischemia Pilot (ACIP) Study

BACKGROUND

Patients with ambulatory electrocardiographic (AECG) ST-segment depression and critical coronary narrowing are known to be at increased risk for adverse outcome, but little is known about patients with AECG ST-segment depression without critical coronary narrowing.

HYPOTHESIS

The objectives of this study were to characterize the coronary angiographic pathology in patients with AECG ST-segment depression but without critical (< 50% diameter stenosis) coronary narrowing and to compare demographic and clinical findings in these patients with those enrolled in the Asymptomatic Cardiac Ischemia Pilot Study with AECG ST-segment depression and critical (> or = 50% diameter stenosis) coronary narrowing.

METHODS

Coronary angiograms from patients with AECG ST-segment depression were reviewed in a central laboratory and quantitative measurement of percent stenosis was performed. Clinical and angiographic comparisons were made between patients with and without critical coronary narrowing.

RESULTS

Patients without critical coronary narrowing (n = 64) were younger (p = 0.02), less likely to be male (p < 0.001) or to have risk factors for coronary atherosclerosis or a history of myocardial infarction (p < 0.001), and had fewer ischemic episodes per 24 h on the screening AECG (p = 0.02) than patients with critical coronary narrowing (n = 441). Of patients without critical narrowing, one half had angiographic evidence for coronary artery disease (> or = 20% stenosis) and 60% had an ejection fraction > 70%.

CONCLUSIONS

Patients with AECG ST-segment depression without critical coronary narrowing are heterogeneous, with half having measurable coronary artery disease. Demographically and clinically, they appear to be different than patients with AECG ST-segment depression with critical coronary narrowing.

Verapamil use in patients with cardiovascular disease: an overview of randomized trials

BACKGROUND

Several reports have questioned the lack of safety data on calcium antagonists as a drug class. Because this drug class is heterogeneous, unique features of certain calcium antagonists may set them apart in terms of safety and efficacy.

HYPOTHESIS

With in excess of 7,000 person-years of observation from randomized clinical trials, verapamil was selected to evaluate whether there was evidence of harm in patients with cardiovascular disease.

METHODS

MEDLINE search of English-language articles, Science Citation Index, Current Contents, manual review of cited references, pharmaceutical files, and investigator correspondence was performed. Independent review of 66 articles identified 14 randomized, parallel-group studies for inclusion. Independent, duplicate assessments were made of patient outcomes and trial characteristics (including study design, treatment dosage and schedule, duration of treatment, inclusion criteria, and sample size). Standard meta-analytic techniques were employed for analysis and interpretation of results.

RESULTS

Based on over 4,000 person-years of observation, patients with acute myocardial infarction (MI) treated with verapamil had a decreased risk of nonfatal reinfarction compared with placebo (relative risk 0.79; 2-sided 95% confidence interval 0.65.0.97; p = 0.024). Verapamil had no significant effect on overall mortality compared with placebo (relative risk ranged from 0.93; 2-sided 95% confidence interval 0.78, 1.10; p = 0.40 to 0.86; 2-sided 95% confidence interval 0.71, 1.04; p = 0.13) depending on rules used to include or exclude patients from the pooling process. For the combined outcome of death or reinfarction, verapamil use was associated with a decreased risk compared with placebo (relative risk 0.82; 2-sided 95% confidence interval 0.70, 0.97; p = 0.016). In patients with angina involving a wide spectrum of disease severity, data were limited to 2,900 person-years of observation, and verapamil use did not appear to be associated with an apparent effect on mortality or MI. Data available from randomized studies of verapamil in patients with hypertension were too limited to reach conclusions (50 person-years of observation, with no deaths or MIs reported). Subgroups of hypertensive patients in two of the largest post-MI studies and the largest angina study, involving over 600 patients, yielded little useful added information.

CONCLUSIONS

In patients with MI, the risks of both nonfatal reinfarction and the combined outcome of death or nonfatal MI were reduced over intermediate-term follow-up among patients treated with verapamil compared with controls (p = 0.024 and p = 0.016, respectively). In patients with angina, no evidence for harm was noted, but in hypertension the data were too limited to draw conclusions. These findings support the need to distinguish among different calcium antagonist compounds and to emphasize the need for more data in patients with hypertension.

Influence of smoking status on progression of endothelial dysfunction. TREND Investigators. Trial on Reversing Endothelial Dysfunction

BACKGROUND

Cigarette smoking is a major risk factor for developing coronary artery disease and is associated with increased coronary morbidity and mortality in patients with established atherosclerosis. This report describes the influence of smoking on coronary endothelial function in normotensive patients with coronary artery disease, but without left ventricular dysfunction, severe hypercholesterolemia, or insulin-dependent diabetes mellitus.

METHODS

Placebo-treated patients (n = 54) from a larger study assessing coronary endothelial function were classified at baseline as smokers or nonsmokers for this subgroup analysis. Patients underwent coronary angiography at baseline and again after 6-month follow-up.

RESULTS

At baseline, there was a trend for a greater decrease in target segment diameter (n = 54) in smokers compared with nonsmokers (-17.2 +/- 5.3% vs. -8.0 +/- 2.5%, acetylcholine 10(-4) mol/l). All measured coronary artery segments (n = 202) showed similar responses (-7.3 +/- 2.7% vs. -3.8 +/- 1.3%, acetylcholine 10(-4) mmol/l, for smokers vs. nonsmokers, respectively). After 6 months, smokers showed an even greater vasoconstrictor response to acetylcholine whereas nonsmokers did not (-21.7 +/- 5.3% vs. -8.3 +/- 2.5%, acetylcholine 10(-4) mmol/l). The vasodilatory response to nitroglycerin was similar in smokers and nonsmokers.

CONCLUSIONS

In current smokers, a marked decline in endothelium-dependent vasomotor response was observed over a 6-month period.

Clinical implications of endothelial dysfunction

Endothelial dysfunction is increasingly recognized as an early event in the pathogenesis of cardiovascular disease. This observation is consistent with the growing appreciation of the role of endothelium in maintaining cardiovascular health. Endothelial dysfunction and coronary artery disease are both linked to hypertension, hypercholesterolemia, diabetes mellitus, and cigarette smoking. Modification of these conditions improves both endothelial function and coronary artery disease outcomes. Dietary and lifestyle modifications and antioxidant vitamin supplementation have a beneficial effect on endothelial function, as do angiotensin-converting enzyme inhibitors and lipid-lowering agents. Future studies will determine whether interventions that specifically target endothelial dysfunction can reduce rates of clinical disease.

Promoter polymorphisms in ACE (angiotensin I-converting enzyme) associated with clinical outcomes in hypertension

Genetic variants of ACE are suspected risk factors in cardiovascular disease, but the alleles responsible for the variations remain unidentified. To search for regulatory polymorphisms, allelic angiotensin I-converting enzyme (ACE) mRNA expression was measured in 65 heart tissues, followed by genotype scanning of the ACE locus. Marked allelic expression imbalance (AEI) detected in five African-American subjects was associated with single-nucleotide polymorphisms (SNPs) (rs7213516, rs7214530, and rs4290) residing in conserved regions 2-3 kb upstream of ACE. Moreover, each of the SNPs affected transcription in reporter gene assays. SNPs rs4290 and rs7213516 were tested for associations with adverse cardiovascular outcomes in hypertensive patients with coronary disease (International Verapamil SR Trandolapril Study Genetic Substudy (INVEST-GENES), n = 1,032). Both SNPs were associated with adverse cardiovascular outcomes, largely attributable to nonfatal myocardial infarction in African Americans, showing an odds ratio of 6.16 (2.43-15.60) (P < 0.0001) for rs7213516. The high allele frequency in African Americans (16%) compared to Hispanics (4%) and Caucasians (<1%) suggests that these alleles contribute to variation between populations in cardiovascular risk and treatment outcomes.

Association of CYP3A5 Polymorphisms with Hypertension and Antihypertensive Response to Verapamil

In the CYP3A5 gene, the A>G (*3) and G>A (*6) polymorphisms result in severely decreased expression of CYP3A5 enzyme relative to a normal functional allele (*1). We sought to determine if the CYP3A5 genetic polymorphisms were associated with level of blood pressure (BP), risk of hypertension (HTN), and the antihypertensive response to verapamil. A total of 676 normotensive and hypertensive participants (mean age 49+/-8.2 years) from the Hypertension Genes study and 722 patients (mean age 66+/-9 years) from the International Verapamil/Trandolapril Study Genetic Substudy (INVEST-GENES) were genotyped for CYP3A5 to test for associations with BP, HTN, and in the latter cohort, antihypertensive response to verapamil. CYP3A5 haplotypes were determined using PHASE 2, with any allele containing either (*3) or (*6) designated as non functional. In the HTN genes population, there were no significant differences based on the number of functional CYP3A5 alleles, in systolic blood pressure (SBP) or diastolic blood pressure (DBP) among the normotensive whites or blacks (all P> or =0.70) or in allele frequency between normotensives and hypertensives. In INVEST-GENES, when controlled for baseline BP, race, age, and gender, untreated BP in carriers versus non carriers of a CYP3A5 functional allele was 158.2+/-13.7 and 154.8+/-13.7 (P=0.061), respectively. CYP3A5 functional allele status was marginally associated with the SBP response to verapamil in blacks (P=0.075) and Hispanics (P=0.056), but not in whites (P=0.40), with the effect being largely driven by higher SBP in the carriers of two functional alleles. There was no association with DBP response and CYP3A5 allele status. CYP3A5 genotype does not contribute importantly to BP or risk of HTN, but may influence response to calcium channel blockers in populations in which carrier status of two functional alleles is common.

Association between β-adrenergic receptor polymorphisms and their G-protein-coupled receptors with body mass index and obesity in women: a report from the NHLBI-sponsored WISE study

OBJECTIVES

The beta-adrenergic receptor (betaAR) genes are candidate genes for obesity because of their roles in energy homeostasis and promotion of lipolysis in human adipose tissue. Objective is to determine the association between obesity and polymorphisms in genes of the beta(1)AR (ADRB1), beta(2)AR (ADRB2), beta(3)AR (ADRB3), Gs protein alpha (GNAS1), to which all three beta-receptors couple and the G protein beta3 subunit (GNB3), to which beta(3)ARs couple.

DESIGN

A case-control genetic association study.

SUBJECTS

A total of 643 black or white women enrolled in Women's Ischemia Syndrome Evaluation (WISE) study.

MEASUREMENTS

Genotypes were determined by PCR with single primer extension. Associations between genotype and body mass index (BMI), waist-to-hip ratio (WHR), waist circumference, and obesity were made.

RESULTS

Polymorphisms in the three betaAR genes, GNAS1, and GNB3 were not associated with BMI, WHR, waist circumference, or obesity. Linear and logistic regression analyses found no contribution of either genotype or haplotype with anthropometric measurements or obesity.

CONCLUSIONS

Our study suggests that among American women with suspected coronary heart disease, polymorphisms in the betaARs and their G-protein-coupled receptors do not contribute to increased BMI, WHR, waist circumference, or obesity. Given that 50% of all women die from coronary heart disease, and a higher percentage have heart disease during their lifetime, our results are likely generalizable to many American women.

Sex differences in chest pain in patients with documented coronary artery disease and exercise-induced ischemia: Results from the PIMI study

BACKGROUND

Sex differences in the pathophysiologic course of coronary artery disease (CAD) are widely recognized, yet accurate diagnosis of coronary artery disease in women remains challenging.

METHODS

To determine sex differences in the clinical manifestation of CAD, we studied chest pain reported during daily activities, exercise, and mental stress in 170 men and 26 women. All patients had documented CAD (>50% narrowing in at least 1 major coronary artery or prior myocardial infarction) and all had 1-mm ST-segment depression on treadmill exercise. We collected psychologic test results, serum samples (potassium, epinephrine, norepinephrine, cortisol, b-endorphin, and glucose), and cardiac function, sensory threshold, and autonomic function data at specified times before, during, or after exercise and mental stress tests to assess measures of depression, anxiety, and neurohormonal and thermal pain perception.

RESULTS

Women reported chest pain more often than men during daily activities (P =.04) and during laboratory mental stressors (P =.01) but not during exercise. Men had lower scores than women on measures of depression, trait anxiety, harm avoidance, and reward dependence (P <.05 for all). Women had significantly lower plasma b-endorphin levels at rest (4.2 +/- 3.9 vs 5.0 +/- 2.5 pmol/L for men, P =.005) and at maximal mental stress (6.4 +/- 5.1 vs 7.4 +/- 3.5 pmol/L for men, P <.01). A higher proportion of women than men had marked pain sensitivity to graded heat stimuli applied to skin (hot pain threshold <41 degrees C, 33% vs 10%, P =.001).

CONCLUSIONS

Our results reflect sex differences in the affective and discriminative aspects of pain perception and may help explain sex-related differences in clinical presentations.

Why vascular biology matters

Cardiovascular disease has been the leading cause of death for men and women in this country since 1921 and is currently the leading cause of death in the world. Adding to the sense of urgency about disease prevention is the recent finding that the initial lesions of atherosclerotic vascular disease may begin within the first year of life-or even earlier, during fetal growth. However, the pathobiology of atherosclerosis (and in particular, the key role of low-density lipoprotein cholesterol) is now well understood. Activation of 3 major oxidative systems as well as the renin-angiotensin system-all located in the vascular wall-is an early step. In fact, the effects of statins and angiotensin-converting enzyme inhibitors on the vascular wall (improved endothelial function, inhibition of platelet aggregation, and plaque stabilization) are an important mechanism of benefit, independent of their systemic effects. Several very positive trials with these agents have been completed. However, if this information is not incorporated into clinical practice in a timely manner, cardiovascular disease will continue to present a major cause of morbidity and mortality worldwide.

Coronary microvascular dysfunction is highly prevalent in women with chest pain in the absence of coronary artery disease: results from the NHLBI WISE study

BACKGROUND

Chest pain in the absence of obstructive coronary artery disease (CAD) is common in women; it is frequently associated with debilitating symptoms and repeated evaluations and may be caused by coronary microvascular dysfunction. However, the prevalence and determinants of microvascular dysfunction in these women are uncertain.

METHODS

We measured coronary flow velocity reserve (coronary velocity response to intracoronary adenosine) to evaluate the coronary microvasculature and risk factors for atherosclerosis in 159 women (mean age, 52.9 years) with chest pain and no obstructive CAD. All women were referred for coronary angiography to evaluate their chest pain as part of the Women's Ischemia Syndrome Evaluation (WISE) study.

RESULTS

Seventy-four (47%) women had subnormal (<2.5) coronary flow velocity reserve suggestive of microvascular dysfunction (mean, 2.02 +/- 0.38); 85 (53%) had normal reserve (mean, 3.13 +/- 0.64). Demographic characteristics, blood pressure, ventricular function, lipid levels, and reproductive hormone levels were not significantly different between women with normal and those with abnormal microvascular function. Postmenopausal hormone use within 3 months was significantly less prevalent among those with microvascular dysfunction (40% vs 60%, P =.032). Age and number of years past menopause correlated with flow velocity reserve (r = -0.18, P =.02, and r = -0.30, P <.001, respectively). No significant associations were identified between flow velocity reserve and lipid and hormone levels, blood pressure, and left ventricular ejection fraction.

CONCLUSIONS

Coronary microvascular dysfunction is present in approximately one half of women with chest pain in the absence of obstructive CAD and cannot be predicted by risk factors for atherosclerosis and hormone levels. Therefore, the diagnosis of coronary microvascular dysfunction should be considered in women with chest pain not attributable to obstructive CAD.

Detailed angiographic analysis of women with suspected ischemic chest pain (pilot phase data from the NHLBI-sponsored Women's Ischemia Syndrome Evaluation [WISE] Study Angiographic Core Laboratory)

The purpose of this study is to provide a contemporary qualitative and quantitative analysis of coronary angiograms from a large series of women enrolled in the Women's Ischemia Syndrome Evaluation (WISE) study who had suspected ischemic chest pain. Previous studies have suggested that women with chest pain have a lower prevalence of significant coronary artery disease (CAD) compared with men. Detailed analyses of angiographic findings relative to risk factors and outcomes are not available. All coronary angiograms were reviewed in a central core laboratory. Quantitative measurement of percent stenosis was used to assess the presence and severity of disease. Of the 323 women enrolled in the pilot phase, 34% had no detectable, 23% had measurable but minimal, and 43% had significant ( > 50% diameter stenosis) CAD. Of those with significant CAD, most had multivessel disease. Features suggesting complex plaque were identified in < 10%. Age, hypertension, diabetes mellitus, prior myocardial infarction (MI), current hormone replacement therapy, and unstable angina were all significant, independent predictors of presence of significant disease (p < 0.05). Subsequent hospitalization for a cardiac cause occurred more frequently in those women with minimal and significant disease compared with no disease (p = 0.001). The common findings of no and extensive CAD among symptomatic women at coronary angiography highlight the need for better clinical noninvasive evaluations for ischemia. Women with minimal CAD have intermediate rates of rehospitalization and cardiovascular events, and thus should not be considered low risk.

Psychosocial variables are associated with atherosclerosis risk factors among women with chest pain: the WISE study

OBJECTIVE

We investigated associations between atherosclerosis risk factors (smoking behavior, serum cholesterol, hypertension, body mass index, and functional capacity) and psychological characteristics with suspected linkages to coronary disease (depression, hostility, and anger expression) in an exclusively female cohort.

METHODS

Six hundred eighty-eight middle-aged women with chest pain warranting clinical investigation completed a comprehensive diagnostic protocol that included quantitative coronary angiography to assess coronary artery disease (CAD). Primary analyses controlled for menopausal status, age, and socioeconomic status variables (income and education).

RESULTS

High depression scores were associated with a nearly three-fold risk of smoking (odds ratio (OR) = 2.8, 95% confidence interval (CI) = 1.4-5.7) after covariate adjustment, and women reporting higher depression symptoms were approximately four times more likely to describe themselves in the lowest category of functional capacity (OR = 3.7, 95% CI = 1.7-7.8). High anger-out scores were associated with a four-fold or greater risk of low high-density lipoprotein cholesterol concentration (<50 mg/dl; OR = 4.0, 95% CI = 1.4-11.1) and high low-density lipoprotein cholesterol concentration (>160 mg/dl; OR = 4.8, 95% CI = 1.5-15.7) and a larger body mass index (OR = 3.5, 95% CI = 1.1-10.8) after covariate adjustment.

CONCLUSIONS

These results demonstrate consistent and clinically relevant relationships between psychosocial factors and atherosclerosis risk factors among women and may aid our understanding of the increased mortality risk among women reporting high levels of psychological distress.

History of anxiety disorders is associated with a decreased likelihood of angiographic coronary artery disease in women with chest pain: the WISE study

OBJECTIVES

We sought to evaluate the ability of psychiatric anxiety-disorder history to discriminate between women with and without angiographic coronary artery disease (CAD) in a population with chest pain.

BACKGROUND

A total of 435 women with chest pain underwent a diagnostic battery including coronary angiography in order to improve testing guidelines for women with suspected CAD.

METHODS

Women referred for coronary angiography completed questionnaires assessing prior treatment history for anxiety disorder and current anxiety-related symptoms. Analyses controlled for standard CAD risk factors.

RESULTS

Forty-four women (10%) reported receiving prior treatment for an anxiety disorder. This group acknowledged significantly higher levels of autonomic symptoms (e.g., headaches, muscle tension [F = 25.0, p < 0.0011 and higher behavioral avoidance scores (e.g., avoidance of open places or traveling alone by bus [F = 4.2, p < 0.05]) at baseline testing compared with women without prior anxiety problems. Women with an anxiety-disorder history did not differ from those without such a history with respect to the presence of inducible ischemia or use of nitroglycerin, although they were younger and more likely to describe both "tight" and "sharp" chest pain symptoms and to experience back pain and episodes of nocturnal chest pain. Logistic regression results indicated that the positive-anxiety-history group was more likely to be free of underlying significant angiographic CAD (odds ratio = 2.74, 95% confidence interval 1.15 to 6.5, p = 0.03).

CONCLUSIONS

Among women with chest pain symptoms, a history of anxiety disorders is associated with a lower probability of significant angiographic CAD. Knowledge of anxiety disorder history may assist in the clinical evaluation of women with chest pain.

An ischemia-guided approach for risk stratification in patients with acute coronary syndromes

The optimal management approach for patients with non-ST-segment elevation acute coronary syndromes continues to be an issue of debate. An ischemia-guided strategy appears to be effective as an alternative to either a very conservative "wait-and-see" approach or a very aggressive routine revascularization approach. The need for another approach is supported by the lack of conclusive evidence-based results favoring an early routine invasive treatment strategy. In the Thrombolysis in Myocardial Infarction (TIMI) IIIB trial, there were no differences in the incidence of death or myocardial infarction (MI) between patients treated with an early invasive approach and those treated with a conservative approach to treatment. Significantly worse outcomes were shown in patients assigned to an early invasive strategy in the Veterans Affairs Non-Q-Wave Infarction Strategies in Hospital (VANQWISH) trial at 1-year follow-up (111 clinical events in the invasive group vs 85 in the conservative group; p = 0.05). Registry information, including that from the Organization to Assess Strategies for Ischemic Syndromes (OASIS), which included approximately 8,000 patients with unstable angina or suspected MI, has even suggested an excess hazard with a routine invasive approach. Patients with non-ST-segment elevation MI observed in the Global Use of Strategies to Open Occluded Coronary Arteries in Acute Coronary Syndromes (GUSTO)-IIB and Platelet IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy (PURSUIT) trials also fared better with an ischemia-guided strategy. Even the recent FRagmin and Fast Revascularization during InStability in Coronary artery disease (FRISC II) trial investigators had to be very selective relative to eliminating high-risk patients in the first week and treating with intense anti-ischemic therapy and 5-7 days of low-molecular-weight heparin therapy to show an advantage for assigned revascularization. A careful clinical evaluation with attention to early risk stratification is essential in the ischemia-guided approach. The Braunwald classification for unstable angina helps identify independent clinical predictors of a poor outcome; high risk is clearly associated with Braunwald class III and type C. Electrocardiographic and biochemical markers for myocardial necrosis (cardiac troponin T or I) are important tools for assessing the presence and degree of ischemia and associated risk for adverse outcome. Noninvasive evaluation of left ventricular ejection fraction is essential for identifying those at high risk due to impaired contractile function. When these conventional markers do not provide conclusive information, noninvasive stress testing is most helpful to further identify those at highest risk for revascularization.

D-Ribose as a supplement for cardiac energy metabolism

Metabolic support for the heart has been an attractive concept since the pioneering work of Sodi-Pallares et al. four decades ago.* Recently, interest has increased in the use of over-the-counter supplements and naturally occurring nutriceuticals for enhancement of cardiac and skeletal muscle performance. These include amino acids such as creatine, L-carnitine, and L-arginine, as well as vitamins and cofactors such as alpha-tocopherol and coenzyme Q. Like these other molecules, D-ribose is a naturally occurring compound. It is the sugar moiety of ATP and has also received interest as a metabolic supplement for the heart. The general hypothesis is that under certain pathologic cardiac conditions, nucleotides (particularly ATP, ADP, and AMP) are degraded and lost from the heart. The heart's ability to resynthesize ATP is then limited by the supply of D-ribose, which is a necessary component of the adenine nucleotide structure. In support of this hypothesis, recent reports have used D-ribose to increase tolerance to myocardial ischemia. Its use in patients with stable coronary artery disease improves time to exercise-induced angina and electrocardiographic changes. In conjunction with thallium imaging or dobutamine stress echocardiography, D-ribose supplementation has been used to enhance detection of hibernating myocardium. In this article, we review the biochemical basis for using supplemental D-ribose as metabolic support for the heart and discuss the experimental evidence for its benefit.

Management of patients with acute coronary syndromes in the United States by platelet glycoprotein IIb/IIIa inhibition. Insights from the platelet glycoprotein IIb/IIIa in unstable angina: receptor suppression using integrilin therapy (PURSUIT) trial

BACKGROUND

A multinational, randomized, placebo-controlled trial (Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy, PURSUIT) demonstrated that the platelet glycoprotein IIb/IIIa receptor antagonist eptifibatide reduced the incidence of death or myocardial infarction among patients with acute ischemic syndromes without ST-segment elevation. Because of expected differences in practice patterns, a prospectively planned analysis of outcomes as a function of regions of the world was performed. The current study provides a detailed assessment of eptifibatide among the subgroup of patients enrolled within the United States.

METHODS AND RESULTS

Patients presenting with chest pain within the previous 24 hours and ischemic ECG changes or creatine kinase-MB elevation were eligible for enrollment. Of the 10 948 patients randomized worldwide, 4035 were enrolled within the United States. Patients were allocated to placebo or eptifibatide infusion for up to 72 to 96 hours. Other medical therapies and revascularization strategies were at the discretion of the treating physician. Eptifibatide reduced the rate of the primary end point of death or myocardial infarction by 30 days from 15.4% to 11.9% (P=0.003) among patients in the United States. The treatment effect was achieved early and maintained over a period of 6 months (18.9% versus 15.2%; P=0.004). Bleeding events were more common in patients receiving eptifibatide but were predominantly associated with invasive procedures. The magnitude of clinical benefit from eptifibatide was greater among patients in the United States than elsewhere in the world.

CONCLUSIONS

Platelet glycoprotein IIb/IIIa receptor blockade with eptifibatide reduces the incidence of death or myocardial infarction among patients treated for acute ischemic syndromes without ST-segment elevation within the United States.

Final results of the Can Routine Ultrasound Influence Stent Expansion (CRUISE) study

BACKGROUND

Intravascular ultrasound (IVUS) can assess stent geometry more accurately than angiography. Several studies have demonstrated that the degree of stent expansion as measured by IVUS directly correlated to clinical outcome. However, it is unclear if routine ultrasound guidance of stent implantation improves clinical outcome as compared with angiographic guidance alone.

METHODS AND RESULTS

The CRUISE (Can Routine Ultrasound Influence Stent Expansion) study, a multicenter study IVUS substudy of the Stent Anti-thrombotic Regimen Study, was designed to assess the impact of IVUS on stent deployment in the high-pressure era. Nine centers were prospectively assigned to stent deployment with the use of ultrasound guidance and 7 centers to angiographic guidance alone with documentary (blinded) IVUS at the conclusion of the procedure. A total of 525 patients were enrolled with completed quantitative coronary angiography, quantitative coronary ultrasound, and clinical events adjudicated at 9 months for 499 patients. The IVUS-guided group had a larger minimal lumen diameter (2.9+/-0.4 versus 2.7+/-0. 5 mm, P<0.001) by quantitative coronary angiography and a larger minimal stent area (7.78+/-1.72 versus 7.06+/-2.13 mm(2), P<0.001) by quantitative coronary ultrasound. Target vessel revascularization, defined as clinically driven repeat interventional or surgical therapy of the index vessel at 9 month-follow-up, occurred significantly less frequently in the IVUS-guided group (8.5% versus 15.3%, P<0.05; relative reduction of 44%).

CONCLUSIONS

These data suggest that ultrasound guidance of stent implantation may result in more effective stent expansion compared with angiographic guidance alone.

American College of Cardiology/ European Society of Cardiology international study of angiographic data compression phase I. The effects of lossy data compression on recognition of diagnostic features in digital coronary angiography

OBJECTIVES

This study intended to determine the effect of varying degrees of lossy Joint Photographic Experts Group (JPEG) compression on detection of coronary angiographic features. Background Compression of digital coronary angiograms facilitates playback of images and decreases cost. There are little data on the effect of compression on the accuracy of coronary angiography.

METHODS

At six centers, 71 angiographers each reviewed a set of 100 angiographic sequences. The 100 sequences were divided into four, 25-sequence subsets. Each subset of 25 was displayed either as original images or at one of three compression ratios (CRs) (6:1, 10:1 or 16:1). The effect of lossy compression on the sensitivity and specificity for detection of diagnostic features was determined. The effect of compression on subjective measures of image quality graded by the angiographers was also examined.

RESULTS

Lossy compression at a ratio of 16:1 decreased the sensitivity for the detection of diagnostic features (76% vs. 80%P=0.004). The largest effect was in the detection of calcification (52% vs. 63% at 16:1 compression vs. original images, P<0.001). Subjective indicators of image quality indicated a reduction in confidence in interpretation at CRs of 10:1 and 16:1.

CONCLUSIONS

With increased ratios of lossy compression, a degradation of digital coronary angiograms occurs that results in decreased diagnostic accuracy. The sensitivity for detection of common diagnostic features was decreased, and subjective assessment of image quality was impaired. Caution is warranted in the interpretation of coronary angiograms that have been subjected to lossy JPEG compression beyond a ratio of 6:1.

American College of Cardiology/European Society of Cardiology International Study of Angiographic Data Compression Phase I: The effect of lossy data compression on recognition of diagnostic features in digital coronary angiography

OBJECTIVES

This study intended to determine the effect of varying degrees of lossy Joint Photographic Experts Group (JPEG) compression on detection of coronary angiographic features.

BACKGROUND

Compression of digital coronary angiograms facilitates playback of images and decreases cost. There are little data on the effect of compression on the accuracy of coronary angiography.

METHODS

At six centers, 71 angiographers each reviewed a set of 100 angiographic sequences. The 100 sequences were divided into four, 25-sequence subsets. Each subset of 25 was displayed either as original images or at one of three compression ratios (CRs) (6:1, 10:1 or 16:1). The effect of lossy compression on the sensitivity and specificity for detection of diagnostic features was determined. The effect of compression on subjective measures of image quality graded by the angiographers was also examined.

RESULTS

Lossy compression at a ratio of 16:1 decreased the sensitivity for the detection of diagnostic features (76% vs. 80% p = 0.004). The largest effect was in the detection of calcification (52% vs. 63% at 16:1 compression vs. original images, p < 0.001). Subjective indicators of image quality indicated a reduction in confidence in interpretation at CRs of 10:1 and 16:1.

CONCLUSIONS

With increased ratios of lossy compression, a degradation of digital coronary angiograms occurs that results in decreased diagnostic accuracy. The sensitivity for detection of common diagnostic features was decreased, and subjective assessment of image quality was impaired. Caution is warranted in the interpretation of coronary angiograms that have been subjected to lossy JPEG compression beyond a ratio of 6:1.

Abnormal myocardial phosphorus-31 nuclear magnetic resonance spectroscopy in women with chest pain but normal coronary angiograms

BACKGROUND

After hospitalization for chest pain, women are more likely than men to have normal coronary-artery angiograms. In such women, myocardial ischemia in the absence of clinically significant coronary-artery obstruction has long been suspected. Most methods for the detection of the metabolic effects of myocardial ischemia are highly invasive. Phosphorus-31 nuclear magnetic resonance (31P-NMR) spectroscopy is a noninvasive technique that can directly measure high-energy phosphates in the myocardium and identify metabolic evidence of ischemia.

METHODS

We enrolled 35 women who were hospitalized for chest pain but who had no angiographically significant coronary-artery obstructions and 12 age- and weight-matched control women with no evidence of heart disease. Myocardial high-energy phosphates were measured with 31P-NMR spectroscopy at 1.5 tesla before, during, and after isometric handgrip exercise at a level that was 30 percent of the maximal voluntary grip strength. We measured the change in the ratio of phosphocreatine to ATP during exercise.

RESULTS

Seven (20 percent) of the 35 women with chest pain and no angiographically significant stenosis had decreases in the phosphocreatine:ATP ratio during exercise that were more than 2 SD below the mean value in the control subjects without chest pain. There were no significant differences between the two groups with respect to hemodynamic variables at rest and during exercise, risk factors for ischemic heart disease, findings on magnetic resonance imaging and radionuclide perfusion studies of the heart, or changes in brachial flow during the infusion of acetylcholine.

CONCLUSIONS

Our results provide direct evidence of an abnormal metabolic response to handgrip exercise in at least some women with chest pain consistent with the occurrence of myocardial ischemia but no angiographically significant coronary stenoses. The most likely cause is microvascular coronary artery disease.

Contracted plasma and blood volume in chronic heart failure

OBJECTIVES

The purpose of this study was to determine if long-term pharmacotherapy mediated changes in intravascular plasma and blood volumes in patients with chronic heart failure (CHF).

BACKGROUND

Intravascular fluid volume expansion is an acute compensatory adaptation to ventricular dysfunction in patients with CHF. To our knowledge there are no reports on plasma and blood volume measures in clinically stable patients with CHF receiving standard pharmacotherapy. Such information may provide a better understanding of the clinical hallmarks of heart failure.

METHODS

Plasma volume (PV) and blood volume (BV) were measured in 12 patients (62.8 +/- 8.2 years old, 175.2 +/- 6.8 cm, 96.2 +/- 18.2 kg, peak oxygen consumption (VO2max) 15.2 +/- 3.3 ml/kg per min) with CHF secondary to coronary artery disease (left ventricular ejection fraction 31.2 +/- 9.7, New York Heart Association functional class 2.5 +/- 0.5) and seven healthy subjects (71.7 +/- 5.3 years old, 177.1 +/- 10.8 cm, 84.4 +/- 11.7 kg, VO2max 26.0 +/- 6.5 ml/kg per min) 3 to 4 h after eating and after supine rest using the Evan's blue dye dilution technique. Venous blood samples were collected before blue dye infusion and analyzed for hematocrit (corrected 4% for trapped plasma and venous to whole body hematocrit ratio) and hemoglobin.

RESULTS

Hematocrit was 36.6 +/- 3.5% and 37.4 +/- 1.1%, and hemoglobin was 15.4 +/- 1.9 and 16.2 +/- 1.4 g/dl for patients with CHF and control subjects, respectively. Absolute PV was 3489.3 +/- 655.0 and 3728.7 +/- 813.2 ml, and absolute BV was 5,496.8 +/- 1,025.4 and 5,942.4 +/- 1,182.2 ml in patients with CHF and control subjects, respectively. Relative PV was 34.1 +/- 12.9 versus 44.5 +/- 9.0 ml/kg (p < or = 0.05), and relative BV was 58.5 +/- 12.3 versus 70.8 +/- 12.6 ml/kg (p < or = 0.05) in patients with CHF and control subjects, respectively.

CONCLUSIONS

Our data indicate significantly lower intravascular volumes in patients with CHF than in control subjects, indicating a deconditioned state or excessive diuresis, or both. The contracted PV and BV may contribute to exercise intolerance, shortness of breath and chronic fatigue, secondary to reduced cardiac output or regional blood flow, or both.

Cost estimates for treatment of cardiac ischemia (from the Asymptomatic Cardiac Ischemia Pilot [ACIP] study)

Costs for management of myocardial ischemia are enormous, yet comparison cost and outcome data for various ischemia treatment strategies from randomized trials are lacking and will require cost and resource utilization data from a large prospective trial. The Asymptomatic Cardiac Ischemia Pilot provided feasibility data for planning such a trial and an opportunity to estimate the long-term costs of different treatment strategies. Economic implications for ischemia management were compared in 558 patients with stable coronary artery disease and myocardial ischemia during both stress testing and daily life. Participants were randomized to 3 different initial treatment strategies and followed for 2 years. Based on cost trends over follow-up, costs for subsequent care were estimated. As expected, due to initial procedural costs, at 3 months, estimated costs for revascularization were approximately 10 times greater than costs for a medical care strategy. Extrapolated costs for anticipated resource consumption for care beyond 2 years, however, were approximately 2 times greater for an initial medical care strategy than for initial revascularization. This was due to increased need for drugs and hospitalizations for both late revascularizations and other ischemia-related events. Estimated costs for anticipated care in the medical strategies reached the anticipated cost of the revascularization strategy within 10 years. Because this cost-equal time period is well within the median life expectancy for such a patient population, these findings could have important public health implications and require testing in a full-scale prognosis trial. We anticipate that over the patients' life expectancy, early revascularization is likely to become either cost-neutral or cost-effective.