Surgical or Percutaneous Repair of Sinus of Valsalva Rupture: Case Series and Literature Review

The rupture of the sinus of the Valsalva aneurysm is a rare but very serious condition. Rapid and accurate diagnosis and prompt treatment are critical for these cases. We present two cases of sinus of Valsalva ruptures. One case was managed with open surgical repair and the second case was treated percutaneously. We have discussed these two therapeutic approaches available to treat sinus of Valsalva rupture.

Mackay Heart Failure Study: Examining the Root Causes, Compliance With Guideline-Based Therapy and Prognosis

INTRODUCTION

Heart failure patients have poor outcomes comparable to some malignancies; however, the modern guideline directed medical therapy (GDMT) has improved its outcomes. The clinical characteristics and prescribers' compliance with GDMT for heart failure patients have not been studied in the Mackay region.

METHODS

A retrospective cohort study of 115 consecutive adult heart failure patients was conducted at our institution.

RESULTS

The study cohort consisted of 80% (n=92) males. Ischaemia was the leading cause accounting for 54% (n=62) of the cohort, followed by idiopathic cardiomyopathy at 32% (n=37). Drug-induced and Takotsubo cardiomyopathies were responsible for 11% and 1% respectively. Two (2) patients (2%) had valvular heart disease. Hypertension was present in 57% while diabetes and atrial fibrillation were present in 32% and 43% of patients. Fifty-nine per cent (59%) had a smoking history. All, except four patients, had reduced left ventricular ejection fraction (LVEF <50%) at diagnosis. Among patients with coronary ischaemia, 37% and 31% were revascularised with percutaneous coronary interventions and bypass graft surgeries, respectively. Renin-angiotensin-aldosterone system inhibitors and beta blockers were prescribed in 94% and 95% of the patients, respectively. Mineralocorticoid inhibitors were used in 25% while ivabradine was given to 8% of patients. Nine per cent (9%) of patients received cardiac resynchronisation therapy. Most patients had improvement in functional class and LVEF during follow-up. There were very few mortalities at 3% (n=3) at the median follow-up of 403 (IQR 239-896) days.

CONCLUSION

Our study has shed light on heart failure epidemiology in the Mackay region. We found excellent compliance with GDMT and good prognosis for most patients in terms of both symptom and survival.

Large-Scale Analysis of Determinants, Stability, and Heritability of High-Density Lipoprotein Cholesterol Efflux Capacity

Supplemental Digital Content is available in the text.

Objective—

Cholesterol efflux capacity (CEC) has emerged as a biomarker of coronary artery disease risk beyond plasma high-density lipoprotein (HDL) cholesterol (HDL-C) level. However, the determinants of CEC are incompletely characterized. We undertook a large-scale family-based population study to identify clinical, biochemical, and HDL particle parameter determinants of CEC, characterize reasons for the discordancy with HDL-C, quantify its heritability, and assess its stability over 10 to 12 years.

Approaches and Results—

CEC was quantified in 1988 individuals from the GRAPHIC (Genetic Regulation of Arterial Pressure of Humans in the Community) cohort, comprising individuals from 2 generations from 520 white nuclear families. Serum lipid and lipoprotein levels were determined by ultracentrifugation or nuclear magnetic resonance and HDL particle size and number quantified by nuclear magnetic resonance. Ninety unrelated individuals had repeat CEC measurements in samples collected after 10 to 12 years. CEC was positively correlated with HDL-C (R=0.62; P<0.0001). Among clinical and biochemical parameters, age, systolic blood pressure, alcohol consumption, serum albumin, triglycerides, phospholipids, and lipoprotein(a) were independently associated with CEC. Among HDL particle parameters, HDL particle number, particle size, and apolipoprotein A-II level were independently associated with CEC. Serum triglyceride level partially explained discordancy between CEC and HDL-C. CEC measurements in samples collected 10 to 12 years apart were strongly correlated (r=0.73; P<0.0001). Heritability of CEC was 0.31 (P=3.89×10⁻¹⁴) without adjustment for HDL-C and 0.13 (P=1.44×10⁻³) with adjustment.

Conclusions—

CEC is a stable trait over time, is influenced by specific clinical, serum, and HDL particle parameters factors beyond HDL-C, can be maintained in persons with a low plasma HDL-C by elevated serum triglyceride level, and is modestly independently heritable.

Determinants of day-night difference in blood pressure, a comparison with determinants of daytime and night-time blood pressure

Blunted day–night difference in blood pressure (BP) is an independent cardiovascular risk factor, although there is limited information on determinants of diurnal variation in BP. We investigated determinants of day–night difference in systolic (SBP) and diastolic (DBP) BP and how these compared with determinants of daytime and night-time SBP and DBP. We analysed the association of mean daytime, mean night-time and mean day–night difference (defined as (mean daytime−mean night-time)/mean daytime) in SBP and DBP with clinical, lifestyle and biochemical parameters from 1562 adult individuals (mean age 38.6) from 509 nuclear families recruited in the GRAPHIC Study. We estimated the heritability of the various BP phenotypes. In multivariate analysis, there were significant associations of age, sex, markers of adiposity (body mass index and waist–hip ratio), plasma lipids (total and low-density lipoprotein cholesterol and triglycerides), serum uric acid, alcohol intake and current smoking status on daytime or night-time SBP and/or DBP. Of these, only age (P=4.7 × 10⁻⁵), total cholesterol (P=0.002), plasma triglycerides (P=0.006) and current smoking (P=3.8 × 10⁻⁹) associated with day–night difference in SBP, and age (P=0.001), plasma triglyceride (P=2.2 × 10⁻⁵) and current smoking (3.8 × 10⁻⁴) associated with day–night difference in DBP. 24-h, daytime and night-time SBP and DBP showed substantial heritability (ranging from 18–43%). In contrast day–night difference in SBP showed a lower heritability (13%) while heritability of day–night difference in DBP was not significant. These data suggest that specific clinical, lifestyle and biochemical factors contribute to inter-individual variation in daytime, night-time and day–night differences in SBP and DBP. Variation in day–night differences in BP is largely non-genetic.

Analysis of gene-gene interactions among common variants in candidate cardiovascular genes in coronary artery disease

Objective

Only a small fraction of coronary artery disease (CAD) heritability has been explained by common variants identified to date. Interactions between genes of importance to cardiovascular regulation may account for some of the missing heritability of CAD. This study aimed to investigate the role of gene-gene interactions in common variants in candidate cardiovascular genes in CAD.

Approach and Results

2,101 patients with CAD from the British Heart Foundation Family Heart Study and 2,426 CAD-free controls were included in the discovery cohort. All subjects were genotyped with the Illumina HumanCVD BeadChip enriched for genes and pathways relevant to the cardiovascular system and disease. The primary analysis in the discovery cohort examined pairwise interactions among 913 common (minor allele frequency >0.1) independent single nucleotide polymorphisms (SNPs) with at least nominal association with CAD in single locus analysis. A secondary exploratory interaction analysis was performed among all 11,332 independent common SNPs surviving quality control criteria. Replication analyses were conducted in 2,967 patients and 3,075 controls from the Myocardial Infarction Genetics Consortium. None of the interactions amongst 913 SNPs analysed in the primary analysis was statistically significant after correction for multiple testing (required P<1.2x10^-7). Similarly, none of the pairwise gene-gene interactions in the secondary analysis reached statistical significance after correction for multiple testing (required P = 7.8x10^-10). None of 36 suggestive interactions from the primary analysis or 31 interactions from the secondary analysis was significant in the replication cohort. Our study had 80% power to detect odds ratios > 1.7 for common variants in the primary analysis.

Conclusions

Moderately large additive interactions between common SNPs in genes relevant to cardiovascular disease do not appear to play a major role in genetic predisposition to CAD. The role of genetic interactions amongst less common SNPs and with medium and small magnitude effects remain to be investigated.

Genetic associations with lipoprotein subfractions provide information on their biological nature

Adverse levels of lipoproteins are highly heritable and constitute risk factors for cardiovascular outcomes. Hitherto, genome-wide association studies revealed 95 lipid-associated loci. However, due to the small effect sizes of these associations large sample numbers (>100 000 samples) were needed. Here we show that analyzing more refined lipid phenotypes, namely lipoprotein subfractions, can increase the number of significantly associated loci compared with bulk high-density lipoprotein and low-density lipoprotein analysis in a study with identical sample numbers. Moreover, lipoprotein subfractions provide novel insight into the human lipid metabolism. We measured 15 lipoprotein subfractions (L1-L15) in 1791 samples using (1)H-NMR (nuclear magnetic resonance) spectroscopy. Using cluster analyses, we quantified inter-relationships among lipoprotein subfractions. Additionally, we analyzed associations with subfractions at known lipid loci. We identified five distinct groups of subfractions: one (L1) was only marginally captured by serum lipids and therefore extends our knowledge of lipoprotein biochemistry. During a lipid-tolerance test, L1 lost its special position. In the association analysis, we found that eight loci (LIPC, CETP, PLTP, FADS1-2-3, SORT1, GCKR, APOB, APOA1) were associated with the subfractions, whereas only four loci (CETP, SORT1, GCKR, APOA1) were associated with serum lipids. For LIPC, we observed a 10-fold increase in the variance explained by our regression models. In conclusion, NMR-based fine mapping of lipoprotein subfractions provides novel information on their biological nature and strengthens the associations with genetic loci. Future clinical studies are now needed to investigate their biomedical relevance.

Post-genomic update on a classical candidate gene for coronary artery disease: ESR1

BACKGROUND

After age, sex is the most important risk factor for coronary artery disease (CAD). The mechanism through which women are protected from CAD is still largely unknown, but the observed sex difference suggests the involvement of the reproductive steroid hormone signaling system. Genetic association studies of the gene-encoding Estrogen Receptor α (ESR1) have shown conflicting results, although only a limited range of variation in the gene has been investigated.

METHODS AND RESULTS

We exploited information made available by advanced new methods and resources in complex disease genetics to revisit the question of ESR1's role in risk of CAD. We performed a meta-analysis of 14 genome-wide association studies (CARDIoGRAM discovery analysis, N=≈87,000) to search for population-wide and sex-specific associations between CAD risk and common genetic variants throughout the coding, noncoding, and flanking regions of ESR1. In addition to samples from the MIGen (N=≈6000), WTCCC (N=≈7400), and Framingham (N=≈3700) studies, we extended this search to a larger number of common and uncommon variants by imputation into a panel of haplotypes constructed using data from the 1000 Genomes Project. Despite the widespread expression of ERα in vascular tissues, we found no evidence for involvement of common or low-frequency genetic variation throughout the ESR1 gene in modifying risk of CAD, either in the general population or as a function of sex.

CONCLUSIONS

We suggest that future research on the genetic basis of sex-related differences in CAD risk should initially prioritize other genes in the reproductive steroid hormone biosynthesis system.

Improved myocardial function after cold storage with preservation solution supplemented with a carbon monoxide-releasing molecule (CORM-3)

BACKGROUND

Carbon monoxide-releasing molecules (CO-RMs) are pharmacologically active as they protect against cardiac graft rejection and cold ischemia-mediated renal dysfunction. We investigated the cardioprotective role of carbon monoxide (CO) released from CORM-3 against cold ischemia-mediated injury in the heart and evaluated its potential application in the clinical setting of cardiac transplantation.

METHODS

Isolated rat hearts underwent cold ischemic storage for 4 or 6 hours using St Thomas Hospital solution that was supplemented with either CORM-3 (50 mumol/liter) or its inactive counterpart (iCORM-3), which does not release CO. Hearts were then reperfused. Both functional parameters and release of cardiac enzymes were assessed.

RESULTS

Addition of CORM-3 to the preservation solution resulted in a significant improvement in systolic and diastolic function as well as coronary flow when compared with hearts treated with iCORM-3. In addition, lower levels of the cardiac enzymes creatine kinase and lactate dehydrogenase were measured in the perfusate of hearts stored with CORM-3.

CONCLUSIONS

The improved functional recovery and reduced enzyme release after cardiac cold storage with CORM-3, but not iCORM-3, indicate that CO is the main mediator of myocardial protection. Thus, CO-RMs can be used as adjuvants to improve the preservation of hearts for transplantation.

Positive inotropic effects of carbon monoxide-releasing molecules (CO-RMs) in the isolated perfused rat heart

BACKGROUND AND PURPOSE

Carbon monoxide (CO) generated by the enzyme haeme oxygenase-1 (HO-1) during the breakdown of haeme is known to mediate a number of biological effects. Here, we investigated whether CO liberated from two water soluble carbon monoxide-releasing molecules (CO-RMs) exerts inotropic effects on the myocardium.

EXPERIMENTAL APPROACH

Rat isolated hearts perfused either at constant flow or constant pressure were used to test the effect of CO-RMs.

KEY RESULTS

CORM-3, a fast CO releaser, produced a direct positive inotropic effect when cumulative doses (3, 10 and 30 microg min(-1)) or a single dose (5 microM) were infused at either constant coronary pressure (CCP) or constant coronary flow (CCF). The inotropic effect mediated by CORM-3 was abolished by blockade of soluble guanylate cyclase or Na(+)/H(+) exchanger, but not by inhibitors of L-type Ca(2+) channels and protein kinase C. CORM-3 also caused a slight reduction in heart rate but did not alter coronary flow. In contrast, the slow CO releaser CORM-A1 produced significant coronary vasodilatation when given at the highest concentration (30 mug min(-1)) but exerted no effect on myocardial contractility or heart rate.

CONCLUSION AND IMPLICATIONS

A rapid CO release from CORM-3 exerts a direct positive inotropic effect on rat isolated perfused hearts, whereas CO slowly released by CORM-A1 had no effect on myocardial contractility but caused significant coronary vasodilatation. Both cGMP and Na(+)/H(+) exchange appear to be involved in this effect but further work is needed to determine the relative contribution of each pathway in CO-mediated inotropic effect.