Cardio-autonomic functions and sleep indices before and after coronary artery bypass surgery.

BACKGROUND: Earlier studies showed a short-term impairment of cardio-autonomic functions following coronary artery bypass grafting (CABG). There is a lack of consistency in the time of recovery from this impairment. Studies have attributed the post-CABG atrial fibrillation to preexisting obstructive sleep apnea (OSA) without an objective sleep assessment. The aim of this study was to evaluate the effect of CABG on cardio-autonomic and hemodynamic functions and on OSA indices in patients with ischemic heart disease (IHD). METHODS: Cardio-autonomic function using heart rate variability indices, hemodynamic parameters, and sleep studies were performed in 26 patients with stable IHD before, on day-6, and day-30 post-CABG surgery. RESULTS: The high-frequency powers of normalized R-R intervals significantly (P = 0.002) increased from the preoperative value of 46.09 to 66.52 on day-6 and remained unchanged on day-30 postsurgery. In contrary, the low-frequency powers of normalized R-R interval decreased from 53.91 to 33.48 during the same period (P = 0.002) and remained unchanged on day 30 postsurgery. Baroreceptor sensitivity, obstructive and central apnea indices, desaturation index, and lowest O2 saturation were not significantly different between preoperative, day-6, and day-30 postsurgery. CONCLUSION: Our study revealed that recovery of autonomic functions following CABG occurs as early as 30 days of postsurgery. CABG does not seem to have short-term effects on sleep study indices. However, long-term effects need further evaluation.

Prevalence Pattern of Risk Factors for Coronary Artery Disease among Patients Presenting for Coronary Artery Bypass Grafting in Oman.

OBJECTIVES: To identify the pattern of prevalence of risk factors in patients presenting for coronary artery bypass grafting at a single center in Oman. METHODS: All patients who had coronary artery bypass grafting between March 2008 to March 2010 were included and data were obtained from history and laboratory investigations. The prevalence rates of eight conventional risk factors are presented as a retrospective single center observational study. RESULTS: Out of 146 total patients, 107 (73.29%) were male. The age ranged from 31 to 87 years old. The mean age was 58.18 ± 10.08 years (males = 56.81 ± 10.42, females = 61.95 ± 7.97). Hypertension was present in 119 patients (81.51%), 115 patients (78.77%) had dyslipidemia, 107 patients (73.29%) were male, 79 patients (54.11%) had diabetes mellitus, 70 patients (47.95%) were over the age of 60 years, 41 patients (28.08%) gave a history of smoking, 31 patients (21.23%) were obese, and 19 patients (13.01%) gave a positive family history. CONCLUSIONS: The most common risk factor was hypertension, followed by dyslipidemia, male gender, diabetes mellitus, old age, smoking, obesity and positive family history; 87.7% had three or more risk factors. The females in this study were older than the males and had more risk factors at presentation. The most common combination of factors seen together was diabetes, hypertension, dyslipidemia and male gender.

Criteria for Diagnosis of Familial Hypercholesterolemia: A Comprehensive Analysis of the Different Guidelines, Appraising their Suitability in the Omani Arab Population.

Subjects with Familial hypercholesterolemia are at increased risk for cardiac events such as premature myocardial infarction and early death from coronary heart disease, especially in patients with severe forms of the disease if left unattended. Therefore, there is an ardent need for the early diagnosis followed by aggressive therapeutic intervention and lifestyle modification. Three groups have developed clinical diagnostic tools for Familial hypercholesterolemia: the US MedPed Program, the Simon Broome Register Group in the United Kingdom, and the Dutch Lipid Clinic Network. In this article, the individual criteria are reviewed with particular emphasis on their advantage(s) and disadvantage(s), and in turn assess their suitability in diagnosing Familial hypercholesterolemia in the Omani Arab population. A brief insight into the process of "Cascade Screening" is also provided, this is a procedure that we are in the process of establishing in Oman.

Low-density lipoprotein receptor gene mutation analysis and structure-function correlation in an Omani arab family with familial hypercholesterolemia.

Familial hypercholesterolemia (FH) is an autosomal dominant disorder typified by elevated low-density lipoprotein cholesterol (LDL-C) levels caused by mutations in the LDL receptor (LDLR), apolipoprotein B (ApoB), or proprotein convertase subtilisin/kexin type 9 (PCSK9) genes. Previously, we reported a novel mutation in the exon-3 of LDLR gene, observed in a 9-year-old Omani Arab female. Here, we investigated the mode of inheritance of this mutation and confirmed that FH in this family is due to mutation only in the LDLR and not PCSK9 and ApoB genes. Further, the effect of the mutation has been appraised in silico on the tertiary structure of LDLR. A model of the mutant LDLR has been constructed using the coordinates of the wild-type LDLR extracellular domain. Based on the model, we present a mechanistic justification behind the observed detrimental effect of the mutation on LDL-C levels.

Saphenous vein graft vs. radial artery graft searching for the best second coronary artery bypass graft.

Coronary artery bypass grafting (CABG) was first used in the late 1960s. This revolutionary procedure created hope among ischemic heart disease patients. Multiple conduits are used and the golden standard is the left internal mammary artery to the left anterior descending artery. Although all approaches were advocated by doctors, the use of saphenous vein grafts became the leading approach used by the majority of cardiac surgeons in the 1970s. The radial artery graft was introduced at the same time but was not as prevalent due to complications. It was reintroduced into clinical practice in 1989. The procedure was not well received initially but it has since shown superiority in patency as well as long-term survival after CABG. This review provides a summary of characteristics, technical features and patency rates of the radial artery graft in comparison with venous conduits. Current studies and research into radial artery grafts and saphenous vein grafts for CABG are explored. However, more studies are required to verify the various findings of the positive effects of coronary artery bypass grafting with the help of radial arteries on mortality and long-lasting patency.

Mutation in the PCSK9 Gene in Omani Arab Subjects with Autosomal Dominant Hypercholesterolemia and its Effect on PCSK9 Protein Structure.

Proprotein convertase subtilisin/kexin type (PCSK9) is a crucial protein in LDL cholesterol (LDL-C) metabolism by virtue of its pivotal role in the degradation of the LDL receptor. Mutations in the PCSK9 gene have previously been found to segregate with autosomal dominant familial hypercholesterolemia (ADFH). In this study, DNA sequencing of the 12 exons of the PCSK9 gene has been performed for two patients with a clinical diagnosis of familial hypercholesterolemia where mutation in the LDL-receptor gene hasn't been excluded. One missense mutation was detected in the exon 9 PCSK9 gene in the two ADFH patients. The patients were found to be heterozygote for Ile474Val (SNP rs562556). Using an array of in silico tools, we have investigated the effect of the above mutation on different structural levels of the PCSK9 protein. Although, the mutation has already been reported in the literature for other populations, to the best of our knowledge this is the first report of a mutation in the PCSK9 gene from the Arab population, including the Omani population.