Effects of a patient-centered digital health intervention in patients referred to cardiac rehabilitation: the Smart HEART clinical trial

BACKGROUND

Cardiac rehabilitation (CR) improves outcomes in heart disease yet remains vastly underutilized. Remote CR enhanced with a digital health intervention (DHI) may offer higher access and improved patient-centered outcomes over non-technology approaches. We sought to pragmatically determine whether offering a DHI improves CR access, cardiac risk profile, and patient-reported outcome measures.

METHODS

Adults referred to CR at a tertiary VA medical center between October 2017 and December 2021 were offered enrollment into a DHI alongside other CR modalities using shared decision-making. The DHI consisted of remote CR with a structured, 3-month home exercise program enhanced with multi-component coaching, a commercial smartphone app, and wearable activity tracker. We measured completion rates among DHI participants and evaluated changes in 6-min walk distance, cardiovascular risk factors, and patient-reported outcomes from pre- to post-intervention.

RESULTS

Among 1,643 patients referred to CR, 258 (16%) consented to the DHI where the mean age was 60 ± 9 years, 93% were male, and 48% were black. A majority (90%) of the DHI group completed the program. Over 3-months, significant improvements were seen in 6MWT (mean difference [MD] -29 m; 95% CI, 10 to 49; P < 0.01) and low-density lipoprotein cholesterol (MD -11 mg/dL; 95% CI, -17 to -5; P < 0.01), and the absolute proportion of patients who reported smoking decreased (10% vs 15%; MD, -5%; 95% CI, -8% to -2%; P < 0.01) among DHI participants with available data. No adverse events were reported.

CONCLUSIONS

The addition of a DHI-enhanced remote CR program was delivered in 16% of referred veterans and associated with improved CR access, markers of cardiovascular risk, and healthy behaviors in this real-world study. These findings support the continued implementation of DHIs for remote CR in real-world clinical settings.

TRIAL REGISTRATION

This trial was registered on ClinicalTrials.gov: NCT02791685 (07/06/2016).

Pseudo-Wellens syndrome, acute pancreatitis, and an anomalous coronary artery: a case report

Background

Chest pain associated with transient electrocardiogram changes mimicking an acute myocardial infarction have been described in acute pancreatitis. These ischemic electrocardiogram changes can present a diagnostic dilemma, especially when patients present with concurrent angina pectoris and epigastric pain warranting noninvasive or invasive imaging studies.

Case presentation

A 45-year-old African-American man with a history of alcohol use disorder presented to the emergency department of our institution with 36 hours of concurrent epigastric pain and left-sided chest pain radiating to his left arm and associated with nausea and dyspnea. On physical examination, he was afebrile; his blood pressure was elevated; and he had epigastric tenderness. His laboratory test results were significant for hypokalemia, normal troponin, and elevated serum lipase and amylase levels. Serial electrocardiograms for persistent chest pain showed ST-segment elevations with dynamic T-wave changes in the right precordial electrocardiogram leads, consistent with Wellens syndrome. He was immediately taken to the cardiac catheterization laboratory, where selective coronary angiography showed normal coronary arteries with an anomalous origin of the right coronary artery from the opposite sinus. Given his elevated lipase and amylase levels, the patient was treated for acute alcohol-induced pancreatitis with intravenous fluids and pain control. His chest pain and ischemic electrocardiogram changes resolved within 24 hours of admission, and coronary computed tomography angiography showed an interarterial course of the right coronary artery without high-risk features.

Conclusions

Clinicians may consider deferring immediate cardiac catheterization and attribute electrocardiogram changes to acute pancreatitis in patients presenting with angina pectoris and acute pancreatitis if confirmed by normal cardiac enzymes and elevated levels of lipase and amylase. However, when clinical signs and electrocardiogram findings are highly suggestive of myocardial ischemia/injury, immediate noninvasive coronary computed tomography angiography may be the best approach to make an early diagnosis.

Pathway-Specific Aggregate Biomarker Risk Score Is Associated With Burden of Coronary Artery Disease and Predicts Near-Term Risk of Myocardial Infarction and Death

BACKGROUND

Inflammation, coagulation, and cell stress contribute to atherosclerosis and its adverse events. A biomarker risk score (BRS) based on the circulating levels of biomarkers C-reactive protein, fibrin degradation products, and heat shock protein-70 representing these 3 pathways was a strong predictor of future outcomes. We investigated whether soluble urokinase plasminogen activator receptor (suPAR), a marker of immune activation, is predictive of outcomes independent of the aforementioned markers and whether its addition to a 3-BRS improves risk reclassification.

METHODS AND RESULTS

C-reactive protein, fibrin degradation product, heat shock protein-70, and suPAR were measured in 3278 patients undergoing coronary angiography. The BRS was calculated by counting the number of biomarkers above a cutoff determined using the Youden's index. Survival analyses were performed using models adjusted for traditional risk factors. A high suPAR level ≥3.5 ng/mL was associated with all-cause death and myocardial infarction (hazard ratio, 1.83; 95% confidence interval, 1.43-2.35) after adjustment for risk factors, C-reactive protein, fibrin degradation product, and heat shock protein-70. Addition of suPAR to the 3-BRS significantly improved the C statistic, integrated discrimination improvement, and net reclassification index for the primary outcome. A BRS of 1, 2, 3, or 4 was associated with a 1.81-, 2.59-, 6.17-, and 8.80-fold increase, respectively, in the risk of death and myocardial infarction. The 4-BRS was also associated with severity of coronary artery disease and composite end points.

CONCLUSIONS

SuPAR is independently predictive of adverse outcomes, and its addition to a 3-BRS comprising C-reactive protein, fibrin degradation product, and heat shock protein-70 improved risk reclassification. The clinical utility of using a 4-BRS for risk prediction and management of patients with coronary artery disease warrants further study.

Age and Human Regenerative Capacity Impact of Cardiovascular Risk Factors

RATIONALE

We investigated aging of human endogenous reparative capacity and aimed to clarify whether it is affected by presence of cardiovascular disease or its risk factors (RFs).

OBJECTIVE

Circulating progenitor cell (PC) levels reflect endogenous regenerative potential. The effect on PC of healthy aging compared with aging with RFs or cardiovascular disease (CVD) is unknown. We examined whether exposure to RF and CVD leads to an accelerated decline in circulating PC with increasing age.

METHODS AND RESULTS

In 2792 adult subjects, 498 were free of RFs (smoking, diabetes mellitus, hypertension, or hyperlipidemia), 1036 subjects had 1 to 2 RF, and 1253 had ≥3 RFs or CVD. PC were enumerated by flow cytometry as CD45(med+) mononuclear cells expressing CD34 and subsets coexpressing CD133, CXCR4, and vascular endothelial growth factor receptor-2 epitopes. Younger age, male sex, and larger body size correlated with higher PC counts (P<0.01). After multivariable adjustment, both age and RF categories were independently associated with PC counts (P<0.05), with lower PC counts in older subjects and those with higher RF burden or CVD. PC counts remained unchanged with increasing age in healthy individuals. There were significant interactions between age and RF categories (P≤0.005), such that for younger subjects (<40 years), RFs were associated with increased PC counts, whereas for older subjects (>60 years), RFs and CVD were associated with lower PC counts.

CONCLUSIONS

Circulating PC levels do not decline with healthy aging; RF exposure at a younger age stimulates PC mobilization, whereas continued exposure is associated with lower PC levels in later life. Over the lifespan, exposure to RFs and CVD is associated with an initial stimulation and subsequent decline in circulating PC levels, which reflect endogenous regenerative capacity.

Abstract 267: Use of Real-time Feedback to Improve Outcomes for In-Hospital Cardiac Arrest: One Center’s Experience

Background: In a 2013 consensus statement, the American Heart Association encouraged the use of real-time feedback during cardiopulmonary resuscitation (CPR) as a recommended best practice for in-hospital cardiac arrest (IHCA). Recent evidence suggests that the use of real-time feedback may lead to improvements in CPR quality in this setting; however there is a paucity of data on its widespread use and effect on outcomes.

Methods: In a single-center retrospective cohort study, we reviewed IHCA event and outcome data from an institutional registry between June 2011 and October 2015. Charts were reviewed to retrieve missing data. Data on CPR-sensing defibrillator (Philips MRx) usage was obtained by direct download from defibrillators. Chi square and fisher exact tests were used for analysis.

Results: We captured 220 reported episodes of IHCA for analysis. CPR-sensing defibrillators were used in only 17 cases (or 7.7% of total events). Return of spontaneous circulation (ROSC) was achieved in 60% of cases. Pulseless electrical activity (PEA) and asystole were the most commonly reported initial rhythm (78.2%), followed by ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) (14.1%) and undocumented cases (7.7%). There was no difference in rates of ROSC or sustained ROSC >20 minutes (p=0.38) based on initial rhythm. Survival to discharge and at 1 year was significantly higher in the VF/pulseless VT group than in the PEA/asystole group (46% vs. 14%, p<0.0001, and 30.4% vs. 5.8%, p=0.0007, respectively). Use of real-time feedback during CPR was not associated with any improvement in the rates of ROSC (p=0.67), survival to discharge (p=0.58) or survival at 1 year (p=0.19).

Conclusions: CPR-sensing defibrillators for real-time feedback were used only in a small minority of cases and were not associated with any improvement in outcomes. Sustained efforts are needed; larger and adequately powered studies may provide clinically relevant information regarding the utility of CPR-sensing defibrillators.

Novel Biomarker of Oxidative Stress Is Associated With Risk of Death in Patients With Coronary Artery Disease

BACKGROUND

Free radical scavengers have failed to improve patient outcomes, promoting the concept that clinically important oxidative stress may be mediated by alternative mechanisms. We sought to examine the association of emerging aminothiol markers of nonfree radical mediated oxidative stress with clinical outcomes.

METHODS AND RESULTS

Plasma levels of reduced (cysteine and glutathione) and oxidized (cystine and glutathione disulphide) aminothiols were quantified by high performance liquid chromatography in 1411 patients undergoing coronary angiography (mean age 63 years, male 66%). All patients were followed for a mean of 4.7 ± 2.1 years for the primary outcome of all-cause death (n=247). Levels of cystine (oxidized) and glutathione (reduced) were associated with risk of death (P<0.001 both) before and after adjustment for covariates. High cystine and low glutathione levels (>+1 SD and <-1 SD, respectively) were associated with higher mortality (adjusted hazard ratio [HR], 1.63; 95% confidence interval [CI], 1.19-2.21; HR, 2.19; 95% CI, 1.50-3.19; respectively) compared with those outside these thresholds. Furthermore, the ratio of cystine/glutathione was also significantly associated with mortality (adjusted HR, 1.92; 95% CI, 1.39-2.64) and was independent of and additive to high-sensitivity C-reactive protein level. Similar associations were found for other outcomes of cardiovascular death and combined death and myocardial infarction.

CONCLUSIONS

A high burden of oxidative stress, quantified by the plasma aminothiols, cystine, glutathione, and their ratio, is associated with mortality in patients with coronary artery disease, a finding that is independent of and additive to the inflammatory burden. Importantly, these data support the emerging role of nonfree radical biology in driving clinically important oxidative stress.

Cerebral Oximetry as a Real-Time Monitoring Tool to Assess Quality of In-Hospital Cardiopulmonary Resuscitation and Post Cardiac Arrest Care

Background

Regional cerebral oxygen saturation (rSO₂) as assessed by near infrared frontal cerebral spectroscopy decreases in circulatory arrest and increases with high-quality cardiopulmonary resuscitation. We hypothesized that higher rSO₂ during cardiopulmonary resuscitation and after return of spontaneous circulation (ROSC) would predict survival to discharge and neurological recovery.

Methods and Results

This prospective case series included patients experiencing in-hospital cardiac arrest. Cerebral oximetry was recorded continuously from initiation of resuscitation until ROSC and up to 48 hours post-arrest. Relationships between oximetry data during these time periods and outcomes of resuscitation survival and survival to discharge were analyzed. The cohort included 27 patients. Nineteen (70.3%) achieved ROSC, and 8 (29.6%) survived to discharge. Median arrest duration was 20.8 minutes (range =8 to 74). There was a significant difference in rSO₂ between resuscitation survivors and resuscitation nonsurvivors at initiation of the resuscitative efforts (35% versus 17.5%, P =0.03) and during resuscitation (36% versus 15%, P =0.0008). No significant association was observed between rSO₂ at ROSC or during the post-arrest period and survival to discharge. Among patients who survived to discharge, there was no association between cerebral performance category and rSO₂ at ROSC, during resuscitation, or post-arrest.

Conclusions

Higher rSO₂ levels at initiation of resuscitation and during resuscitation are associated with resuscitation survival and may reflect high-quality cardiopulmonary resuscitation. However, in this small series, rSO₂ was not predictive of good neurological outcome. Larger studies are needed to determine whether this monitoring modality can be used to improve clinical outcomes.

Plasma stromal cell-derived factor 1α/CXCL12 level predicts long-term adverse cardiovascular outcomes in patients with coronary artery disease

OBJECTIVE

Stromal derived factor-1α/CXCL12 is a chemoattractant responsible for homing of progenitor cells to ischemic tissues. We aimed to investigate the association of plasma CXCL12 with long-term cardiovascular outcomes in patients with coronary artery disease (CAD).

METHODS

785 patients aged: 63 ± 12 undergoing coronary angiography were independently enrolled into discovery (N = 186) and replication (N = 599) cohorts. Baseline levels of plasma CXCL12 were measured using Quantikine CXCL12 ELISA assay (R&D systems). Patients were followed for cardiovascular death and/or myocardial infarction (MI) for a mean of 2.6 yrs. Cox proportional hazard was used to determine independent predictors of cardiovascular death/MI.

RESULTS

The incidence of cardiovascular death/MI was 13% (N = 99). High CXCL12 level based on best discriminatory threshold derived from the ROC analysis predicted risk of cardiovascular death/MI (HR = 4.81, p = 1 × 10(-6)) independent of traditional risk factors in the pooled cohort. Addition of CXCL12 to a baseline model was associated with a significant improvement in c-statistic (AUC: 0.67-0.73, p = 0.03). Addition of CXCL12 was associated with correct risk reclassification of 40% of events and 10.5% of non-events. Similarly for the outcome of cardiovascular death, the addition of the CXCL12 to the baseline model was associated with correct reclassification of 20.7% of events and 9% of non-events. These results were replicated in two independent cohorts.

CONCLUSION

Plasma CXCL12 level is a strong independent predictor of adverse cardiovascular outcomes in patients with CAD and improves risk reclassification.

Circulating CD34+ progenitor cells and risk of mortality in a population with coronary artery disease

RATIONALE

Low circulating progenitor cell numbers and activity may reflect impaired intrinsic regenerative/reparative potential, but it remains uncertain whether this translates into a worse prognosis.

OBJECTIVES

To investigate whether low numbers of progenitor cells associate with a greater risk of mortality in a population at high cardiovascular risk.

METHODS AND RESULTS

Patients undergoing coronary angiography were recruited into 2 cohorts (1, n=502 and 2, n=403) over separate time periods. Progenitor cells were enumerated by flow cytometry as CD45(med+) blood mononuclear cells expressing CD34, with additional quantification of subsets coexpressing CD133, vascular endothelial growth factor receptor 2, and chemokine (C-X-C motif) receptor 4. Coefficient of variation for CD34 cells was 2.9% and 4.8%, 21.6% and 6.5% for the respective subsets. Each cohort was followed for a mean of 2.7 and 1.2 years, respectively, for the primary end point of all-cause death. There was an inverse association between CD34(+) and CD34(+)/CD133(+) cell counts and risk of death in cohort 1 (β=-0.92, P=0.043 and β=-1.64, P=0.019, respectively) that was confirmed in cohort 2 (β=-1.25, P=0.020 and β=-1.81, P=0.015, respectively). Covariate-adjusted hazard ratios in the pooled cohort (n=905) were 3.54 (1.67-7.50) and 2.46 (1.18-5.13), respectively. CD34(+)/CD133(+) cell counts improved risk prediction metrics beyond standard risk factors.

CONCLUSIONS

Reduced circulating progenitor cell counts, identified primarily as CD34(+) mononuclear cells or its subset expressing CD133, are associated with risk of death in individuals with coronary artery disease, suggesting that impaired endogenous regenerative capacity is associated with increased mortality. These findings have implications for biological understanding, risk prediction, and cell selection for cell-based therapies.

Sex and age differences in the association of depression with obstructive coronary artery disease and adverse cardiovascular events

Background

Young women with coronary heart disease have high rates of depression and a higher risk of adverse events than men of similar age. Whether depression has a higher prognostic value in this group than in men and older women is not known. Our objective was to assess whether depression in young women is associated with higher risk of coronary artery disease (CAD) and adverse outcomes compared with similarly aged men and older women.

Methods and Results

We examined 3237 patients undergoing coronary angiography for evaluation of CAD and followed them for 2.9 years (median). Depressive symptoms were assessed with the Patient Health Questionnaire (PHQ)‐9, and CAD burden was dichotomized based on its presence or absence. After multivariable adjustment for CAD risk factors, depressive symptoms predicted CAD presence in women aged ≤55 years (odds ratio=1.07 95% confidence interval [CI] 1.02 to 1.13 per 1 point increase in PHQ‐9 score), but not in men aged ≤55 years or women aged >55 years. Depressive symptoms also predicted increased risk of death in women aged ≤55 years (adjusted hazard ratio=1.07, 95% CI 1.02 to 1.14, per 1 point increase in PHQ‐9 score), but not in men aged ≤55 years and women aged >55 years, with P=0.02 for the depression‐sex interaction and P=0.02 for depression‐sex‐age interaction.

Conclusions

Among patients with suspected or established CAD, depressive symptoms are associated with increased risk of death, particularly in young women. This group may be especially vulnerable to the adverse cardiovascular effects of depression.

Oxidative stress is associated with increased pulmonary artery systolic pressure in humans

Oxidative stress contributes to the development of pulmonary hypertension in experimental models, but this association in humans is unknown. We investigated the relationship between pulmonary artery systolic pressure measured by echocardiography and plasma aminothiol oxidative stress markers, with the hypothesis that oxidative stress will be higher in those with pulmonary hypertension. A group of 347 patients aged 65±12 years from the Emory Cardiovascular Biobank underwent echocardiographic assessment of left ventricular ejection fraction and pulmonary artery systolic pressure. Plasma aminothiols, cysteine, its oxidized form, cystine, glutathione, and its oxidized disulphide were measured and the redox potentials (Eh) of cysteine/cystine and glutathione/oxidized glutathione couples were calculated. Non-normally distributed variables were log transformed (Ln). Univariate predictors of pulmonary artery systolic pressure included age (P<0.001), sex (P=0.002), mitral regurgitation (P<0.001), left ventricular ejection fraction (P<0.001), left atrial size (P<0.001), diabetes mellitus (P=0.03), plasma Ln cystine (β=9.53; P<0.001), Ln glutathione (β=-5.4; P=0.002), and Eh glutathione (β=0.21; P=0.001). A multivariate linear regression model adjusting for all confounding variables demonstrated that Ln cystine (β=6.56; P=0.007), mitral regurgitation (β=4.52; P<0.001), statin use (β=-3.39; P=0.03), left ventricular ejection fraction (β=-0.26; P=0.003), and age (β=0.17; P=0.003) were independent predictors of pulmonary artery systolic pressure. For each 1% increase in plasma cystine, pulmonary artery systolic pressure increased by 16%. This association persisted in the subgroup with preserved left ventricular ejection fraction (≥50%) and no significant mitral regurgitation. Whether treatment of oxidative stress will improve pulmonary hypertension requires further study.

Myocardial ischemia during mental stress: role of coronary artery disease burden and vasomotion

Background

Mental stress–induced myocardial ischemia (MSIMI) is associated with adverse prognosis in patients with coronary artery disease (CAD), yet the mechanisms underlying this phenomenon remain unclear. We hypothesized that compared with exercise/pharmacological stress–induced myocardial ischemia (PSIMI) that is secondary to the atherosclerotic burden of CAD, MSIMI is primarily due to vasomotor changes.

Methods and Results

Patients with angiographically documented CAD underwent ^99mTc‐sestamibi myocardial perfusion imaging at rest and following both mental and physical stress testing, performed on separate days. The severity and extent of CAD were quantified using the Gensini and Sullivan scores. Peripheral arterial tonometry (Itamar Inc) was used to assess the digital microvascular tone during mental stress as a ratio of pulse wave amplitude during speech compared with baseline. Measurements were made in a discovery sample (n=225) and verified in a replication sample (n=159). In the pooled (n=384) sample, CAD severity and extent scores were not significantly different between those with and without MSIMI, whereas they were greater in those with compared with those without PSIMI (P<0.04 for all). The peripheral arterial tonometry ratio was lower in those with compared with those without MSIMI (0.55±0.36 versus 0.76±0.52, P=0.009). In a multivariable analysis, the peripheral arterial tonometry ratio was the only independent predictor of MSIMI (P=0.009), whereas angiographic severity and extent of CAD independently predicted PSIMI.

Conclusions

The degree of digital microvascular constriction, and not the angiographic burden of CAD, is associated with MSIMI. Varying causes of MSIMI compared with PSIMI may require different therapeutic interventions that require further study.

Association between the chromosome 9p21 locus and angiographic coronary artery disease burden: a collaborative meta-analysis

OBJECTIVES

This study sought to ascertain the relationship of 9p21 locus with: 1) angiographic coronary artery disease (CAD) burden; and 2) myocardial infarction (MI) in individuals with underlying CAD.

BACKGROUND

Chromosome 9p21 variants have been robustly associated with coronary heart disease, but questions remain on the mechanism of risk, specifically whether the locus contributes to coronary atheroma burden or plaque instability.

METHODS

We established a collaboration of 21 studies consisting of 33,673 subjects with information on both CAD (clinical or angiographic) and MI status along with 9p21 genotype. Tabular data are provided for each cohort on the presence and burden of angiographic CAD, MI cases with underlying CAD, and the diabetic status of all subjects.

RESULTS

We first confirmed an association between 9p21 and CAD with angiographically defined cases and control subjects (pooled odds ratio [OR]: 1.31, 95% confidence interval [CI]: 1.20 to 1.43). Among subjects with angiographic CAD (n = 20,987), random-effects model identified an association with multivessel CAD, compared with those with single-vessel disease (OR: 1.10, 95% CI: 1.04 to 1.17)/copy of risk allele). Genotypic models showed an OR of 1.15, 95% CI: 1.04 to 1.26 for heterozygous carrier and OR: 1.23, 95% CI: 1.08 to 1.39 for homozygous carrier. Finally, there was no significant association between 9p21 and prevalent MI when both cases (n = 17,791) and control subjects (n = 15,882) had underlying CAD (OR: 0.99, 95% CI: 0.95 to 1.03)/risk allele.

CONCLUSIONS

The 9p21 locus shows convincing association with greater burden of CAD but not with MI in the presence of underlying CAD. This adds further weight to the hypothesis that 9p21 locus primarily mediates an atherosclerotic phenotype.

Angiotensin receptor type 1 single nucleotide polymorphism 1166A/C is associated with malignant arrhythmias and altered circulating miR-155 levels in patients with chronic heart failure

BACKGROUND

Sudden cardiac death (SCD) from ventricular tachyarrhythmias accounts for approximately 450,000 annual deaths in the United States; many of these cases involve patients with chronic heart failure (HF). Prediction of which HF patients are most susceptible to SCD is difficult, and it is uncertain whether gene polymorphisms associated with HF outcomes are also linked to arrhythmic risk.

METHODS

We evaluated 485 patients with chronic HF to see whether the angiotensin receptor type 1 (AT1R) 1166A/C or angiotensin-converting enzyme insertion/deletion (ACE I/D) polymorphisms were associated with a higher rate of ventricular arrhythmias requiring implantable cardioverter defibrillator (ICD) therapies over a 5-year period. We assessed the correlation between polymorphisms and antitachycardia pacing (ATP) and/or ICD shocks.

RESULTS

Patients with AT1R-1166CC genotype had an increased rate of all events: ATP plus ICD shocks (P = .02). There was no association between ACE I/D genotype and ICD therapies. Furthermore, circulating levels of microRNA-155 (miR-155), a microRNA known to posttranscriptionally regulate AT1R expression, were significantly decreased in the CC compared with the AC and AA genotypes and were associated with ICD events.

CONCLUSION

Our study suggests that the AT1R-1166CC genotype is associated with increased ICD therapies in patients with chronic HF, and the level of circulating miR-155 may be a potential marker for arrhythmic risk. Although these findings are novel, they will need replication and validation in larger cohorts of chronic HF patients.

Association of a genetic risk score with prevalent and incident myocardial infarction in subjects undergoing coronary angiography

BACKGROUND

Genome-wide association studies have identified multiple variants associating with coronary artery disease (CAD) and myocardial infarction (MI). Whether a combined genetic risk score (GRS) is associated with prevalent and incident MI in high-risk subjects remains to be established.

METHODS AND RESULTS

In subjects undergoing cardiac catheterization (n=2597), we identified cases with a history of MI onset at age <70 years and controls ≥70 years without prior MI and followed them for incident MI and death. Genotyping was performed for 11 established CAD/MI variants, and a GRS was calculated based on average number of risk alleles carried at each locus weighted by effect size. Replication of association findings was sought in an independent angiographic cohort (n=2702). The GRS was significantly associated with prevalent MI, occurring before age 70, compared with older controls (≥70 years of age) with no history of MI (P<0.001). This association was successfully replicated in a second cohort, yielding a pooled P value of <0.001. The GRS modestly improved the area-under-the-curve statistic in models of prevalent MI with traditional risk factors; however, the association was not statistically significant when elderly controls without MI but with s\ angiographic CAD were examined (pooled P=0.11). Finally, during a median 2.5-year follow-up, only a nonsignificant trend was noted between the GRS and incident events, which was also not significant in the replication cohort.

CONCLUSIONS

A GRS of 11 CAD/MI variants is associated with prevalent MI but not near-term incident adverse events in 2 independent angiographic cohorts. These findings have implications for understanding the clinical use of genetic risk scores for secondary as opposed to primary risk prediction.

Mitochondrial reactive oxygen species and calcium uptake regulate activation of phagocytic NADPH oxidase

Production of superoxide (O(2)(·-)) by NADPH oxidases contributes to the development of hypertension and atherosclerosis. Factors responsible for activation of NADPH oxidases are not well understood; interestingly, cardiovascular disease is associated with both altered NADPH oxidase activity and age-associated mitochondrial dysfunction. We hypothesized that mitochondrial dysfunction may contribute to activation of NADPH oxidase. The effect of mitochondrial inhibitors on phagocytic NADPH oxidase in human lymphoblasts and whole blood was measured at the basal state and upon PKC-dependent stimulation with PMA using extracellular 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl-trimethylammonium or mitochondria-targeted 1-hydroxy-4-[2-triphenylphosphonio)-acetamido]-2,2,6,6-tetramethylpiperidine spin probes and electron spin resonance (ESR). Intracellular cytosolic calcium [Ca(2+)](i) was measured spectrofluorometrically using fura-2 AM. Incubation of lymphoblasts with the mitochondrial inhibitors rotenone, antimycin A, CCCP, or ruthenium red (an inhibitor of mitochondrial Ca(2+) uniporter) did not significantly change basal activity of NADPH oxidase. In contrast, preincubation with the mitochondrial inhibitors prior to PMA stimulation of lymphoblasts resulted in two- to three-fold increase of NADPH oxidase activity compared with stimulation with PMA alone. Most notably, the intracellular Ca(2+)-chelating agent BAPTA-AM abolished the effect of mitochondrial inhibitors on NADPH oxidase activity. Cytosolic Ca(2+) measurements with fura-2 AM showed that the mitochondrial inhibitors increased [Ca(2+)](i), while BAPTA-AM abolished the increase in [Ca(2+)](i). Furthermore, depletion of cellular Ca(2+) with thapsigargin attenuated CCCP- and antimycin A-mediated activation of NADPH oxidase in the presence of PMA by 42% and 31%, correspondingly. Our data suggest that mitochondria regulate PKC-dependent activation of phagocytic NADPH oxidase. In summary, increased mitochondrial O(2)(·-) and impaired buffering of cytosolic Ca(2+) by dysfunctional mitochondria result in enhanced NADPH oxidase activity, which may contribute to the development of cardiovascular diseases.

A brief journey into the history of the arterial pulse

Objective. This paper illustrates the evolution of our knowledge of the arterial pulse from ancient times to the present. Several techniques for arterial pulse evaluation throughout history are discussed. Methods. Using databases including Worldcat, Pubmed, and Emory University Libraries' Catalogue, the significance of the arterial pulse is discussed in three historical eras of medicine: ancient, medieval, and modern. Summary. Techniques used over time to analyze arterial pulse and its characteristics have advanced from simple evaluation by touch to complex methodologies such as ultrasonography and plethysmography. Today's understanding of the various characteristics of the arterial pulse relies on our ancestors' observations and experiments. The pursuit of science continues to lead to major advancements in our knowledge of the arterial pulse and its application in diagnosis of atherosclerotic disease.

A common variant in the CDKN2B gene on chromosome 9p21 protects against coronary artery disease in Americans of African ancestry

Background

A 58kb region on chromosome 9p21.3 has consistently shown strong association with coronary artery disease (CAD) in multiple genome-wide association studies in populations of European and East Asian ancestry. In this study we sought to further characterize the role of genetic variants in 9p21.3 in African American individuals.

Methods and Results

Apparently healthy African American siblings (n=548) of patients with documented CAD <60 years of age were genotyped and followed for incident CAD for up to 17 years. Tests of association for 86 SNPs across the 9p21.3 region in a GEE logistic framework under an additive model adjusting for traditional risk factors, family, follow-up time, and population stratification were performed. A single SNP within the CDKN2B gene met stringent criteria for statistical significance, including permutation-based evaluations. This variant, rs3217989, was common (minor allele [G] frequency 0.242), conveyed protection against CAD (OR=0.19, 95% CI: 0.07 to 0.50, p=0.0008) and was replicated in a combined analysis of two additional case/control studies of prevalent CAD/MI in African Americans (n=990, p=0.024, OR= 0.779, 95% CI: 0.626-0.968).

Conclusions

This is the first report of a CAD association signal in a population of African ancestry with a common variant within the CDKN2B gene, independent from previous findings in European and East Asian ancestry populations. The findings demonstrate a significant protective effect against incident CAD in African American siblings of persons with premature CAD, with replication in a combination of two additional African American cohorts.

The chromosome 9p21 risk locus is associated with angiographic severity and progression of coronary artery disease

AIMS

we tested the hypothesis that the 9p21 risk locus promotes atherosclerosis by examining the association between rs10757278 and coronary artery disease (CAD) severity and progression determined by semi-quantitative angiographic scores.

METHODS AND RESULTS

the rs10757278 single nucleotide polymorphism (SNP) was genotyped as the marker for the 9p21 locus in 2334 Caucasian patients undergoing cardiac catheterization (mean age 63, male 67%). Angiographic CAD was assessed using two semi-quantitative scoring systems with one estimating severity (Gensini) and the other extent (Sullivan). A subset of 308 patients who underwent two or more coronary angiograms at least 6 months apart were examined for net change in Gensini and Sullivan scores over time to determine the rate of CAD progression by genotype and were further classified as 'progressors' or 'non-progressors' based on absolute change per year in angiographic severity score. We replicated the association between the rs10757278 SNP and myocardial infarction and binary (presence/absence) angiographic classifications of CAD. Furthermore, we observed a significant additive association with this SNP, and both severity and extent of CAD using angiographic scores, after adjustment for age, gender, body mass index, traditional cardiovascular risk factors, myocardial infarction, and statin use (Gensini P = 0.016, Sullivan P = 0.005). In addition, there was a significant linear association with CAD progression before and after adjustment for covariates (Gensini P = 0.023, Sullivan P = 0.003) with homozygotes for the risk variant having three-fold greater odds of CAD progression compared with the referent group.

CONCLUSION

the 9p21 risk locus is associated with angiographically defined severity, extent, and progression of CAD, suggesting a role for this locus in influencing atherosclerosis and its progression.

A rare coincidence of two coronary anomalies in an adult

Anomalous right-sided left main coronary arteries and dual type IV left anterior descending arteries are rare coronary anomalies. In this case report, we present a 59 year old man with atypical chest pain and a combination of the above coronary anomalies as identified by selective coronary angiography and computed tomography angiography. To the best of our knowledge, the coincidence of these coronary anomalies has not been previously described.

The C242T CYBA polymorphism as a major determinant of NADPH oxidase activity in patients with cardiovascular disease

Single nucleotide polymorphisms (SNP) in the CYBA gene encoding p22(phox) have been associated with respiratory burst and cardiovascular phenotypes. We previously reported a reduced phagocytic respiratory burst activity in healthy adults with the C242T SNP, but found no correlation between CYBA SNPs and coronary artery disease (CAD) phenotype. Using lymphoblastoid cells, we hypothesized that CYBA SNPs affect enzyme activity in patients with cardiovascular disease (CVD), but would not be associated with angiographic severity of CAD due to confounding by risk factors. We established lymphoblastoid cell lines from patients with CVD and genotyped the study cohort for CYBA SNPs and phenotyped each subject's coronary angiogram for CAD severity. As quantified by electron spin resonance, superoxide production in picomoles per 10(6) resting lymphoblastoid cells per minute for the CC, CT, and TT genotypes of the C242T SNP were 16.2+/-1.4, n=70, 11.9+/-0.7, n=87, and 11.9+/-1.5, n=28, respectively (P=0.002). The -930(A/G) and A640G SNPs did not affect superoxide production (P > 0.2). Expression of p22(phox) was not affected as determined by real-time RT-PCR and Western blot analysis. The C242T CYBA SNP is associated with altered NADPH oxidase activity in lymphoblastoid cells of patients with CVD. By reducing the influence of confounding environmental factors, lymphoblastoid cell lines could serve as a tool to assess direct genotype/phenotype interactions of candidate genes known to affect atherosclerosis.

Automated external cardioversion defibrillation monitoring in cardiac arrest: a randomized trial

Background

In-hospital cardiac arrest has a poor prognosis despite active electrocardiography monitoring. The initial rhythm of approximately 25% of in-hospital cardiopulmonary resuscitation (CPR) events is pulseless ventricular tachycardia/ventricular fibrillation (VT/VF). Early defibrillation is an independent predictor of survival in CPR events caused by VT/VF. The automated external cardioverter defibrillator (AECD) is a device attached by pads to the chest wall that monitors, detects, and within seconds, automatically delivers electric countershock to an appropriate tachyarrhythmia.

Study Objectives

• To evaluate safety of AECD monitoring in hospitalized patients.

• To evaluate whether AECDs provide earlier defibrillation than hospital code teams.

Methods

The study is a prospective trial randomizing patients admitted to the telemetry ward to standard CPR (code team) or standard CPR plus AECD monitoring (PowerHeart CRM). The AECD is programmed to deliver one 150 J biphasic shock to patients in sustained VT/VF. Data is collected using the Utstein criteria for cardiac arrest. The primary endpoint is time-to-defibrillation; secondary outcomes include neurological status and survival to discharge, with 3-year follow-up.

Results

To date, 192 patients have been recruited in the time period between 10/10/2006 to 7/20/2007. A total of 3,655 hours of telemetry data have been analyzed in the AECD arm. The AECD has monitored ambulatory telemetry patients in sinus rhythm, sinus tachycardia, supraventricular tachycardia, atrial flutter or fibrillation, with premature ventricular complexes and non-sustained VT without delivery of inappropriate shocks. One patient experienced sustained VT during AECD monitoring, who was successfully defibrillated (17 seconds after meeting programmed criteria). There are no events to report in the control arm. The patient survived the event without neurological complications. During the same time period, mean time to shock for VT/VF cardiac arrest occurring outside the telemetry ward was 230 ± 50 seconds.

Conclusion

AECD monitoring is safe and likely results in earlier defibrillation than standard telemetry monitoring.

Trial Registration

National Institutes of Health registration ID: NCT00382928

Human heart failure is associated with abnormal C-terminal splicing variants in the cardiac sodium channel

Heart failure (HF) is associated with reduced cardiac Na+ channel (SCN5A) current. We hypothesized that abnormal transcriptional regulation of this ion channel during HF could help explain the reduced current. Using human hearts explanted at the transplantation, we have identified 3 human C-terminal SCN5A mRNA splicing variants predicted to result in truncated, nonfunctional channels. As compared with normal hearts, the explanted ventricles showed an upregulation of 2 of the variants and a downregulation of the full-length mRNA transcript such that the E28A transcript represented only 48.5% (P<0.01) of the total SCN5A mRNA. This correlated with a 62.8% (P<0.01) reduction in Na+ channel protein. Lymphoblasts and skeletal muscle expressing SCN5A also showed identical C-terminal splicing variants. Variants showed reduced membrane protein and no functional current. Transfection of truncation variants into a cell line stably transfected with the full-length Na+ channel resulted in dose-dependent reductions in channel mRNA and current. Introduction of a premature truncation in the C-terminal region in a single allele of the mouse SCN5A resulted in embryonic lethality. Embryonic stem cell-derived cardiomyocytes expressing the construct showed reductions in Na+ channel-dependent electrophysiological parameters, suggesting that the presence of truncated Na+ channel mRNA at levels seen in HF is likely to be physiologically significant. In summary, chronic HF was associated with an increase in 2 truncated SCN5A variants and a decrease in the native mRNA. These splice variations may help explain a loss of Na+ channel protein and may contribute to the increased arrhythmic risk in clinical HF.

Narrative review: cardiopulmonary resuscitation and emergency cardiovascular care: review of the current guidelines

Sudden cardiac death is a major clinical problem, causing 300,000 to 400,000 deaths annually and 63% of all cardiac deaths. Despite the overall decrease in cardiovascular mortality, the proportion of cardiovascular death from sudden cardiac death has remained constant. Survival rates among patients who have out-of-hospital cardiac arrest vary from 5% to 18%, depending on the presenting rhythm. The latest guidelines for cardiopulmonary resuscitation (CPR) and emergency cardiovascular care published by the American Heart Association include substantial changes to the algorithms for basic life support and advanced cardiovascular life support. For unwitnessed cardiac arrest, immediate defibrillation of the patient is no longer recommended. Rather, 2 minutes of CPR before defibrillation is now recommended. People in cardiac arrest should no longer receive stacked shocks. The compression-ventilation ratio has been changed from 15:2 to 30:2. This article is a contemporary review of the management of CPR and emergency cardiovascular care. It examines current practice and data supporting use of CPR, along with changes in the management of sudden cardiac death.

Long-term survival after successful inhospital cardiac arrest resuscitation

BACKGROUND

Little is known about long-term outcomes of patients who survive inhospital cardiac arrest.

METHODS

We examined long-term survival after inhospital cardiac arrest and whether procedural changes that improved survival to discharge impacted long-term survival. Consecutive inhospital arrests in the Atlanta Veterans Affairs Medical Center (Atlanta, GA) from 1995 to 2004 (n = 732) were retrospectively analyzed. Data regarding the arrest was obtained, including age, left ventricular ejection fraction, medications, and comorbidities, presenting rhythm, location of arrest, code duration, and outcomes. Long-term mortality data was obtained based on chart and Social Security Death Index reviews. Further data was gathered on internal cardioverter-defibrillator presence and use in survivors.

RESULTS

Overall, 49 subjects (6.6%) survived to discharge. Univariate analysis found that ventricular tachycardia/ventricular fibrillation and the use of beta-blockers, angiotensin-converting enzyme inhibitors, and antiarrhythmics at the time of arrest were associated with increased survival, whereas advancing age and comorbidities were associated with a higher risk of mortality. Multivariate analysis determined that age, rhythm, and comorbidities independently affected survival. Implementation of a resuscitation program previously documented to improve survival to discharge did not translate to durable long-term survival. Three-year survival rate after discharge was only 41%. Alternatively, subjects with internal cardioverter-defibrillator showed a 36% improvement in 3-year survival rate to 77% (P = .001).

CONCLUSIONS

Subjects with inhospital cardiac arrest have poor long-term prognoses. A strategy that improved inhospital survival did not alter long-term mortality rate. Thus, survival to discharge may not be a sufficient end point for future resuscitation trials.

Production of extracellular superoxide by human lymphoblast cell lines: comparison of electron spin resonance techniques and cytochrome C reduction assay

Superoxide production by NADPH oxidases plays an important role in the development and progression of cardiovascular disease (CVD). However, measurement of superoxide (O(2)(-)), a marker of oxidative stress, remains a challenging task in clinical and translational studies. In this study we analyzed O(2)(-) production in cultured human lymphoblast cell lines by three different methods: (a) superoxide dismutase (SOD)-inhibitable cytochrome C reduction, (b) spin trapping of superoxide with 5-(ethoxycarbonyl)-5-methyl-1-pyrroline N-oxide (EMPO) and 5-diethoxyphosphoryl-5-methyl-1-pyrroline N-oxide (DEPMPO), and (c) using electron spin resonance (ESR) with the cell-permeable spin probe 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine (CMH). Lymphocytes were isolated and immortalized by an Epstein-Barr Virus (EBV)-transformation procedure. Superoxide was measured in cultured lymphoblast cell lines at baseline and upon stimulation with phorbol 12-myristate 13-acetate (PMA). Cytochrome C and the spin traps EMPO and DEPMPO detected two to five times less superoxide compared to CMH. Thus, CMH provided the most quantitative measurement of superoxide generation in human lymphoblast cell lines. Superoxide detection with CMH was linear dependent on cell concentration and was inhibited by SOD but not by catalase. Both cell-permeable polyethylene glycol (PEG)-SOD and extracellular Cu,Zn-SOD inhibited O(2)(-) detection by 90% in PMA-stimulated cells, suggesting a predominantly extracellular O(2)(-) generation in human lymphoblasts. Our study describes a new technique for O(2)(-) measurement in cultured human lymphoblasts using ESR and CMH. A highly sensitive in vitro measurement of O(2)(-) in human cell lines would allow investigators to study genotype/phenotype interactions in translational studies.

Circulating Chlamydia pneumoniae DNA and advanced coronary artery disease

BACKGROUND

Chlamydia pneumoniae (C. pneumoniae) has been linked to atherosclerosis. Detection of this pathogen in peripheral blood cells may be valuable in the diagnosis of disease state. This study aimed to evaluate the prevalence of circulating C. pneumoniae DNA and its relationship with severity and extent of coronary artery disease (CAD).

METHODS

Blood samples from 269 patients undergoing coronary angiography were collected. The presence of circulating C. pneumoniae DNA was determined by real-time PCR assay. Data regarding coronary risk factors and severity and extent of CAD were collected. Severity and extent of CAD was defined by the number of major epicardial coronary arteries with >50% stenosis and by the Duke jeopardy score.

RESULTS

Sixteen of 269 specimens (5.9%) from the study cohort were positive for C. pneumoniae DNA. Thirteen specimens among 149 samples from patients with multi-vessel disease (8.7%) were positive for C. pneumoniae DNA compared with 3 of 120 (2.5%) among patients without multi-vessel CAD. The prevalence of circulating C. pneumoniae DNA was significantly associated with multi-vessel disease. The odds ratio was 5.1 (P=0.02) after adjustment for conventional risk factors.

CONCLUSIONS

Presence of circulating C. pneumoniae DNA is associated with advanced CAD, suggesting C. pneumoniae infection as a contributing factor to progression of coronary atherosclerosis.

Endothelial nitric oxide synthase intron 4 polymorphism is a marker for coronary artery disease in African-American and Caucasian men

OBJECTIVES

We investigated the association of the intron 4 polymorphism of the endothelial nitric oxide synthase (eNOS) gene with coronary artery disease (CAD).

BACKGROUND

Genetic alterations in the gene encoding for eNOS could contribute to the development and progression of CAD.

METHODS

We genotyped for the eNOS intron 4 polymorphism in 194 subjects undergoing coronary angiography. Genotyping was performed with polymerase chain reaction-restriction fragment length polymorphism for the variable number of tandem repeats in intron 4. Coronary artery disease (CAD) was assessed by quantitative coronary angiography, and endothelial function was measured by brachial ultrasonography. We performed logistic regression analysis for the effect of eNOS intron 4 polymorphism and other coronary risk factors on multi-vessel CAD and endothelial function.

RESULTS

The 4a-allele frequency in African Americans was 0.31, while the 4a-allele frequency in Caucasians was 0.15 (P<.001). The prevalence of the 4a-allele was highest among subjects with multi-vessel disease both for African Americans and for Caucasians. A race-adjusted comparison of the prevalence of the 4a-allele among subjects with multi-vessel disease vs those without was statistically significant (P=.03). No correlation was found between the eNOS intron 4 polymorphism and endothelial function.

CONCLUSIONS

The eNOS intron 4 polymorphism may be a marker of multi-vessel CAD in African Americans and Caucasians.

A program encouraging early defibrillation results in improved in-hospital resuscitation efficacy

OBJECTIVES

The purpose of this study was to determine whether survival to discharge after in-hospital cardiopulmonary arrest could be improved by a program encouraging early defibrillation that included switching from monophasic to biphasic devices.

BACKGROUND

In-hospital resuscitation continues to have a low success rate. Biphasic waveform devices have demonstrated characteristics that might improve survival, and outside the hospital, automated external defibrillators (AEDs) have shown promise in improving survival of patients suffering cardiopulmonary arrest.

METHODS

A program including education and replacement of all manual monophasic defibrillators with a combination of manual biphasic defibrillators used in AED mode and AEDs in all outpatient clinics and chronic care units was implemented.

RESULTS

With program implementation, the percentage survival of all patients with resuscitation events improved 2.6-fold, from 4.9% to 12.8%. Factors independently predicting survival included event location outside an intensive care unit, younger age, an initial rhythm of pulseless ventricular tachycardia (VT) or ventricular fibrillation (VF), pre-arrest beta-blocker, and program initiation. The outcome was independent of gender, race, work shift, number of previous resuscitation attempts, body mass index, comorbidity index, presence of diabetes, presence of hypertension, or use of angiotensin-converting enzyme inhibitors. The improvement in mortality was attributable solely to an effect on patients presenting with VT/VF. Patients with these initial rhythms were 14-fold (odds ratio = 0.07 of death, confidence interval = 0.02 to 0.3) more likely to survive to discharge after program initiation. Automated external defibrillators performed similarly to biphasic manual defibrillators in AED mode.

CONCLUSIONS

A program including education and use of biphasic manual defibrillators in AED mode and selective use of AEDs improved survival to discharge in hospitalized patients suffering from cardiopulmonary arrest.

C242TCYBAPolymorphism of the NADPH Oxidase Is Associated With Reduced Respiratory Burst in Human Neutrophils

Oxidative stress contributes to the pathogenesis of atherosclerosis. p22phox-based NAD(P)H oxidases exist in the vessel wall, acting as important superoxide-generating systems in the vasculature. Some studies have identified reduced atherosclerosis in the presence of the C242T CYBA polymorphism, whereas others have not. Because vascular p22phox is identical to neutrophil p22phox, we studied the association between the C242T, A640G, and -930A/G CYBA polymorphisms and the quantity of superoxide produced from neutrophils isolated from healthy adults to determine if these polymorphisms had any functional impact on NADPH oxidase function. Neutrophils were isolated from 90 subjects by Percoll density gradient centrifugation. Genotypes were determined by polymerase chain reaction (PCR) and restriction mapping, as well as real-time PCR. The oxidative burst was stimulated with phorbol 12-myristate 13-acetate. Superoxide was quantified using the superoxide dismutase inhibitable oxidation of the spin probe hydroxylamine 1-hydroxy-3-carboxy-pyrrolidine, detected by electron paramagnetic resonance. Superoxide production was significantly affected by the C242T polymorphism, being 8.7+/-0.7, 7.9+/-0.6, and 5.9+/-1.2 micromol/L per minute per 10(6) neutrophils for the C242T CC, CT, and TT genotypes, respectively (P<0.05). In contrast, the A640G and the -930A/G polymorphisms did not alter the neutrophil respiratory burst. Phagocytic respiratory burst activity in homozygous individuals with the T allele of the C242T CYBA polymorphism is significantly lower than of wild-type carriers and heterozygous individuals. Because p22phox exists in both the neutrophil and vessel wall, vascular oxidative stress is likely diminished in individuals with this polymorphism.

Transient abnormal Q waves during exercise electrocardiography

Myocardial ischaemia during exercise electrocardiography is usually manifested by ST segment depression or elevation. Transient abnormal Q waves are rare, as Q waves indicate an old myocardial infarction. The case of a patient with exercise induced transient abnormal Q waves is reported. The potential mechanisms involved in the development of such an abnormality and its clinical implications are discussed.

The A640G and C242T p22(phox) polymorphisms in patients with coronary artery disease

Oxidative stress plays a significant role in the pathogenesis of coronary artery disease (CAD). A p22(phox)-based NAD(P)H oxidase acts as a potent superoxide-generating system in the vasculature. We studied the association of the A640G and the C242T polymorphisms with clinical risk factors, endothelial function, and severity of CAD in a cohort of 216 patients referred for coronary angiography. The frequency of p22(phox) genotypes for AA, AG, and GG was 22.5, 52.3, and 25.2%, and for CC, CT, and TT 35.5, 51.3, and 13.2%, respectively. The A640G and the C242T polymorphisms were not associated with severity of CAD and endothelial function. The frequency distribution of the genotypes among patients with or without angiographically significant CAD did not reach statistical significance. Our study does not support a functional role for the A640G or C242T polymorphisms either in the severity of CAD or in determining endothelial function in older men.

Genetic polymorphisms and oxidative stress in heart failure

Heart failure results from various known cardiovascular diseases, such as coronary artery disease, or can be the result of an idiopathic dilated cardiomyopathy. It is of utmost importance for diagnostic, preventive, and therapeutic purposes to understand the cellular events that trigger the cascade of functional and structural changes that result in the development and progression of heart failure. Progress in unraveling the genetic background in both ischemic and nonischemic cardiomyopathies has been slow compared with that for monogenic diseases, such as some forms of hypertrophic cardiomyopathy or familial dilated cardiomyopathies. It is likely that susceptibility to and risk of progression of heart failure are both influenced by many genes acting in concert or independently. Among the diverse subcellular mechanisms implicated in the pathogenesis and progression of heart failure, reactive oxygen species play a major role. The search for genetic polymorphisms in clinical association studies in order to identify genotypes susceptible to develop and affect the progression to heart failure has been the focus of many investigations over the past several years. In this review, the authors summarize the current data in support of the role of various polymorphisms of genes related to oxidative stress in the susceptibility to develop heart failure, and its progression.

An unusual case of groin discomfort

Groin complications after cardiac catheterizations are common. With the increasing use of mechanical hemostatic devices, cardiologists must be alert to a wide array of potential problems. We report an unusual complication after the use of a closure device.

Arachidonic acid metabolites mediate angiotensin II-induced NADH/NADPH oxidase activity and hypertrophy in vascular smooth muscle cells

Previously, we showed that angiotensin II stimulation of the NADH/NADPH oxidase is involved in hypertrophy of cultured vascular smooth muscle cells (VSMC). Here, we examine the pathways leading to oxidase activation, and demonstrate that arachidonic acid metabolites mediate hypertrophy by activating the p22phox-based NADH/NADPH oxidase. Angiotensin II stimulates phospholipase A2, releasing arachidonic acid, which stimulates oxidase activity in vitro. When arachidonic acid metabolism is blocked with 5,8,11,14-eicosatetraynoic acid (ETYA) or nordihydroguaiaretic acid (NDGA), oxidase activity decreases by 80 +/- 10%. In VSMC transfected with antisense p22phox to attenuate NADH/NADPH oxidase expression, arachidonic acid is unable to stimulate NADH/NADPH-dependent superoxide production. In these cells, or in cells in which NADH/NADPH oxidase activity is inhibited by diphenylene iodonium, angiotensin II-induced [3H]leucine incorporation is also inhibited. Attenuation of oxidase activation by inhibiting arachidonic acid metabolism with ETYA, NDGA, baicalein, or SKF-525A also inhibits angiotensin II-stimulated protein synthesis (74 +/- 2% and 34 +/- 1%, respectively). Thus, endogenous noncyclooxygenase arachidonic acid metabolites mediate angiotensin II-stimulated protein synthesis in cultured VSMC by activating the NADH/NADPH oxidase, providing mechanistic evidence for redox control of VSMC hypertrophy.

Role of NADH/NADPH oxidase-derived H2O2 in angiotensin II-induced vascular hypertrophy

Recent evidence suggests that oxidative mechanisms may be involved in vascular smooth muscle cell (VSMC) hypertrophy. We previously showed that angiotensin II (Ang II) increases superoxide production by activating an NADH/NADPH oxidase, which contributes to hypertrophy. In this study, we determined whether Ang II stimulation of this oxidase results in H2O2 production by studying the effects of Ang II on intracellular H2O2 generation, intracellular superoxide dismutase and catalase activity, and hypertrophy. Ang II (100 nmol/L) significantly increased intracellular H2O2 levels at 4 hours. Neither superoxide dismutase activity nor catalase activity was affected by Ang II; the SOD present in VSMCs is sufficient to metabolize Ang II-stimulated superoxide to H2O2, which accumulates more rapidly than it is degraded by catalase. This increase in H2O2 was inhibited by extracellular catalase, diphenylene iodonium, an inhibitor of the NADH/NADPH oxidase, and the AT1 receptor blocker losartan. In VSMCs stably transfected with antisense p22phox, a critical component of the NADH/NADPH oxidase in which oxidase activity was markedly reduced, Ang II-induced production of H2O2 was almost completely inhibited, confirming that the source of Ang II-induced H2O2 was the NADH/NADPH oxidase. Using a novel cell line that stably overexpresses catalase, we showed that this increased H2O2 is a critical step in VSMC hypertrophy, a hallmark of many vascular diseases. Inhibition of intracellular superoxide dismutase by diethylthiocarbamate (1 mmol/L) also resulted in attenuation of Ang II-induced hypertrophy (62+/-2% inhibition). These data indicate that AT1 receptor-mediated production of superoxide generated by the NADH/NADPH oxidase is followed by an increase in intracellular H2O2, suggesting a specific role for these oxygen species and scavenging systems in modifying the intracellular redox state in vascular growth.