2010 Vol. 7, No. 2
In the United States, there are about 17.6 million patients suffer from symptomatic coronary artery disease (CAD), affecting 7.9% of adults ≥20 years of age. An estimated 10.2 million patients have angina, and 500,000 patients will develop new angina pectoris each year. A subset of angina patients are categorized as refractory when symptoms continue despite optimal medical therapy and revascularization. Routine daily activities become impossible without experiencing chest pain in this patient population.
There are four stages in medical device development. The beginning starts with some new understanding of physiological concepts which evolve into the formation of an innovative idea. The second stage is the technical development tphase, from idea to the development of a design to technical reality. At this stage, capital funding and patent applications for the development are necessary but they are not considered here. The third stage is experimental and clinical studies, a data gathering phase to provide evidence of safety and effectiveness of the applications of the device. The final stage is society adaptation and acceptance. These four stages do not occur in series but constantly interact and feedback on each other, evolving on their way to maturity.
External counterpulsation (ECP) was originally conceived to be a circulatory assist device to promote blood flow to areas of the heart muscle that were lacking adequate blood supply due to obstruction of the coronary artery. During ECP the lower extremities are compressed to squeeze both arterial and venous blood back to the heart during diastole, increasing coronary perfusion pressure and right ventricular filling. The compression is released during systole, effectively increasing peripheral arterial capacitance and thereby lowering impedance to cardiac ejection and systolic workload. Enhanced external counterpulsation (EECP) was designed in the late 1970s with three pneumatic cuffs wrapped around the calves, lower and upper thighs. These cuffs are inflated sequentially to increase the volume of peripheral blood that can be effectively pumped back towards the heart. During the last four decades EECP has been demonstrated to be clinically effective in the treatment of patients with coronary artery disease. However, beside the acute hemodynamic effects that can be readily observed during EECP treatment, its mechanisms of action and its long-term effects are less well established and have only been rigorously examined within the past five years. Theoretically, EECP treatment can provide benefit through enhanced recruitment of collateral circulation and a variety of peripheral vascular effects, including improved endothelial function. Collaterals are small vessels that supply arterial blood to ischemic myocardium distal to the obstructed artery. They are created by the increased pressure gradient across a vascular stenosis and by angiogenic factors released as a result of the vascular shear forces produced during EECP treatment. In fact the most promising and beneficial effects of EECP treatment may involve these measurable and reproducible peripheral and endothelial effects of EECP treatment and will be the primary focus of this review.
Reduced blood flow is the principle pathophysiologic event in acute ischemic stroke. Hence, flow augmentation is the most important goal in stroke management. Improvement of cerebral blood flow can be accomplished by proximal arterial recanalization or by other systemic approaches. Diastolic counterpulsation is a non-invasive method to improve the perfusion of heart, kidneys and brain. This review summarizes the history, possible mechanism and the role of external counterpulsation in ischemic stroke
Objective Congestive heart failure (CHF) is the final common pathway of various heart diseases. Calcineurin, a calcium/calmodulindependent phosphatase consisting of a catalytic subunit A (CnA) and a regulatory calcium-binding subunit B (CnB), is activated in heart failure. This study aimed to investigate the relationship between mRNA level of calcineurin in circulating T-lymphocyte and that in myocardium in patients with CHF. Methods A total of 38 patients with CHF (aged from 29 to 62 years) were included in this study. The mRNA levels of alpha- and beta-isoform of CnA in left ventricular anterior papillary muscle and peripheral lymphocytes were determined by semi-quantitative reverse transcription polymerase chain reaction. Pearson linear correlation analysis was performed, and difference was considered statistically significant at a P value <0.05. Results Calcineurin mRNA levels in lymphocytes were positively correlated with those in myocardium (for CnA-alpha mRNA, r=0.820; for CnA-beta mRNA, r=0.875; both P<0.01). CnA-beta mRNA levels in both circulating lymphocytes and myocardium increased significantly with increasing NYHA class (r=0.877 for peripheral blood and r=0.805 for cardiac muscle; both P<0.01). Conclusions The mRNA level of CnA-beta in circulating lymphocytes is positively correlated with that in myocardium and is a promising marker for the severity of cardiac dysfunction in patients with CHF.
Objective To assess the risk factors for prehypertension in Xinjiang Uygur population.Methods A cross-section study was conducted in a Xinjiang Uygur population (438 males and 716 females, aged 30 to 70 years). The fasting lipid profiles, serum glucose, insulin, and uric acid were determined. Homeostasis model assessment of insulin resistance (HOMA-IR) index was used to assess insulin resistance (IR). Binary logistic regression analysis was performed to determine risk factors for prehypertension. Blood pressure levels of normotensives and prehypertensives in different body mass index (BMI) categories were compared.Results Binary logistic regression analysis performed after adjustment for gender, lipids profiles, waist-to-hip ratio, uric acid, HOMA-IR, and lifestyle (alcohol drinking and smoking) showed a significantly increasing prevalence of prehypertension with BMI. The odds ratios for prehypertension against the lowest BMI group (separated by 24 and 28) were 1.934 and 2.490 (95% confidence interval: 1.435-2.606 and1.825-3.399, respectively). Age was independently correlated to the increasing prevalence of prehypertension. HOMA-IR was not associated with prehypertensive. The mean diastolic blood pressure (DBP) was significantly increased with BMI categories in either normotensives or prehypertensives (P<0.001) while the mean systolic blood pressure (SBP) was significantly increased with BMI only in normotensives (P<0.001).Conclusions In Xinjiang Uygurs, BMI and age was the risk factors for prehypertension. DBP is significantly increased with BMI. IR is not associated with prehypertension. These findings emphasize the importance of management of obesity for the control of blood pressure and other cardiovascular complications.
Objective Biochemical indicators such as N-terminal pro-brain type natriuretic peptide (NT pro-BNP) and high-sensitivity Creactive protein (hsCRP) predict mortality in acute coronary syndrome (ACS). However, little is known about the relationship of these factors with severity of coronary artery stenosis in patients with. Methods Three hundred and thirty-one subjects including 246 unstable angina pectoris patients and 85 myocardial infarction patients were recruited and classified into two groups: single-vessel disease group (1-vessel disease, n= 93) and multiple-vessel disease group (≥2- vessels disease, n=238) according to selective coronary angiography. Plasma levels of NT pro-BNP and hsCRP were measured and severity of coronary stenosis was determined by Gensini score. Results NT pro-BNP but not hsCRP level was higher in patients with myocardial infarction than in patients with unstable angina pectoris. The patients with multiple-vessel disease had significantly higher NT pro-BNP level but not hsCRP compared with those with single-vessel disease. NT pro-BNP levels increased significantly as left ventricle (LV) function decreased, and only NT pro-BNP but not hsCRP level was related to Gensini score of severity of coronary stenosis in ACS. Conclusion NT pro-BNP but not hsCRP level is related to severity of coronary artery stenosis in patients in ACS.
Objective To explore the effect of inflammation and autoimmunity in peripartum cardiomyopathy (PPCM). Methods A total of 82 PPCM patients and 100 normal delivery patients were randomly selected and conducted epidemiological survey. High-sensitivity Creaction protein (hs-CRP), troponin I, human antimyocardial antibody IgG (AMA-IgG), Coxsackie B virus IgG (CBV-IgG) and adenovirus antibody IgG (ADV- IgG) were detected with ELISA. Results Compared with control group, PPCM patients had older age, higher pressure, higher proportion of cesarean section and infection. The levels of serum hs-CRP, cTNI, and leucocyte were markedly higher in PPCM patients compared with control. The positive proportion of AMA-IgG and CBV-IgG was significantly increased (P<0.01) in PPCM patients compared with the control. Logistic regression showed that infection (OR=2.87, 95%CI 1.15-5.24), increased hs-CRP (OR=1.86, 95%CI 1.08-4.02) and positive AMA-IgG (OR=2.68, 95%CI 1.19-4.85) were independent risk factors for PPCM. Conclusions Inflammation and autoimmunity play an important role in peripartum cardiomyopathy.
Objective To study the safety and effect of the umbilical cord blood (UCB)-derived mesenchymal stem cells (MSCs) on apoptosis of human cardiomyocytes (HCM). Methods UCB was collected at the time of delivery with informed consent obtained from 10 donors. The UCB-derived MSCs were treated with 5-azaserube (5-AZA) and were further induced to differentiate into cardiomyocytes. Telomerase activity, G-banding patterns of chromosomal karyotypes, tumor formation in nude mice, RT-PCR, and the effect of inhibiting apoptosis of HCM were investigated. Results MSCs derived from UCB were differentiated into cardiomyocytes in vitro, which possessed telomerase activity after 5-AZA induction, and no abnormal chromosomal karyotypes were observed. Expression of p53, cyclin A, cdk2, β-actin, C-fos, h-TERT and c-myc were similar in MSCs before and after 5-AZA treatment. There was no tumor formation in nude mice after injection of UCB-derived MSCs. UCB-derived MSCs significantly inhibited apoptosis of HCM. Conclusion UCB-derived MSCs are a valuable, safe and effective source of cell-transplantation treatment.
Hypertension is a leading cause of mortality and morbidity around the world and, prevalence of hypertension is increasing with aging. Hypertension in the elderly is associated with increased occurrence rates of sodium sensitivity, isolated systolic hypertension, and 'white coat effect'. Arterial stiffness and endothelial dysfunction also increase with age. These factors should be considered in selecting antihypertensive therapy. The prime objective of this therapy is to prevent stroke. The findings of controlled trials show that there should be no cut-off age for treatment. A holistic program for controlling cardiovascular risks should be fully discussed with the patient, including evaluation to exclude underlying causes of secondary hypertension, and implementation of lifestyle measures. The choice of antihypertensive drug therapy is influenced by concomitant disease and previous medication history, but will typically include a thiazide diuretic as the first-line agent; to this will be added an angiotensin inhibitor and/or a calcium channel blocker. Beta blockers are not generally recommended, in part because they do not combat the effects of increased arterial stiffness. The hypertension-hypotension syndrome requires case-specific management. Drug-resistant hypertension is important to differentiate from faulty compliance with medication. Patients resistant to the third-line drug therapy may benefit from treatment with extended-release isosorbide mononitrate. A trial of spironolactone may also be worthwhil.
Simvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, is widely prescribed to patients with hypercholesteremia and its muscular toxicity has been widely reported. The metabolism of simvastatin depends on the enzymic activity of cytochrome P450 3A4 (CYP3A4) and inhibitors of CYP3A4 can result in clinical events by interacting with simvastatin. Diltiazem is a moderate inhibitor of CYP3A4, which is known to increase the serum concentration of simvastatin. Here we report a patient with unrecognized hypothyroidism who had been stable for more than one year on low-dose simvastatin therapy of hypercholesteremia and rhabdomyolysis occurred with the addition of diltiazem. This is one of scanty reports of rhabdomyolysis induced by simvastatindiltiazem drug interaction, especially in hypothyroid patient. This case reminds the clinicians that although diltiazem as a moderate CYP3A4 inhibitor can be used cautiously with small doses of CYP3A4-dependent statins (eg, simvastatin), these two commonly used drugs should be avoided in hypothyroid patient.