Wilson W.M. Chan

Left atrial appendage closure with Amplatzer cardiac plug for stroke prevention in atrial fibrillation: Initial Asia‐Pacific experience

Background: Left atrial appendage (LAA) is the main source of left atrial thrombus that causes stroke in patients with non‐valvular atrial fibrillation (NVAF). This study reported the initial safety, feasibility, and 1‐yr clinical outcomes following AMPLATZER cardiac plug (ACP) implantation in Asia‐Pacific region.Methods: Twenty NVAF patients (16 males, age 68 ± 9 yr) with high risk for developing cardioembolic stroke (CHADS2 score: 2.3 ± 1.3) and contraindications to warfarin received ACP implants from June 2009 to May 2010. Patients received general anesthesia (n = 9) or controlled propofol sedation (n = 11) and the procedures were guided by fluoroscopy and transesophageal echocardiography (TEE). Clinical follow‐up was arranged at 1 month and then every 3 months after implantation, whereas, a TEE was scheduled at 1 month upon completion of dual anti‐platelet therapy.Results: The LAA was successfully occluded in 19/20 patients (95%) at two Asian centers. One procedure was abandoned because of catheter‐related thrombus formation. Other complications included coronary artery air embolism (n = 1) and TEE‐attributed esophageal injury (n = 1). The median procedural and fluoroscopic times were 79 (IQR: 59–100) and 18 (IQR 12–27) minutes, respectively. The mean size of implant was 23.6 ± 3.1 mm. The average hospital stay was 1.8 ± 1.1 days. Follow‐up TEE showed all the LAA orifices were sealed without device‐related thrombus formation. No stroke or death occurred at a mean follow‐up of 12.7 ± 3.1 months. Conclusions: Our preliminary data suggested LAA closure with ACP is safe, feasible with encouraging 1‐yr clinical outcomes. Further large‐scaled trials are needed to confirm the efficacy of this device.

Effect of low dose beta blockers on atrial and ventricular (B type) natriuretic factor in heart failure: a double blind, randomised comparison of metoprolol and a third generation vasodilating beta blocker.

OBJECTIVES--This study examines the acute effects of two differing beta adrenergic blocking agents (metoprolol and a third generation vasodilating beta blocker) on plasma concentrations of atrial natriuretic factor (ANF), brain (ventricular) natriuretic factor (BNF), and haemodynamic variables in patients with heart failure. SETTING--University teaching hospital. METHODS--20 patients with impaired left ventricular systolic function [ejection fraction 32 (SEM 2.3)%] were randomised in a double blind manner to receive either oral metoprolol 6.25 mg twice daily or celiprolol 25 mg daily. Haemodynamic variables were evaluated by Swan-Ganz pulmonary artery catheter over 24 hours. ANF and BNF concentrations were measured at baseline, 5 h, and 24 h by radioimmunoassay. RESULTS--At baseline ANF and BNF concentrations were considerably raised compared to the normal range. Treatment with metoprolol caused ANF to rise further to 147% of the basal level at 5 h (P = 0.017) and 112% at 24 h (P = 0.029). This was associated with a small but non-significant rise in pulmonary capillary wedge pressure. Cardiac output and systemic vascular resistance were unchanged at 24 h. In contrast, after celiprolol ANF fell to 90% of basal levels at 5 h and to 74% of basal level at 24 h (P = 0.019), associated with a small but non-significant fall in pulmonary capillary wedge pressure [-3.3 (2.7) mm Hg] and systemic vascular resistance, and rise in cardiac output from 3.2 (0.2) to 4.0 (0.4) l/min (P = 0.04). BNF concentrations rose to 112% of baseline at 5 h (P = 0.09) after metoprolol but fell slightly, to 91% of baseline values, after celiprolol (NS). CONCLUSIONS--Metoprolol, even in very low doses (6.25 mg), produced a rise in ANF and BNF, although minimal haemodynamic changes were detected. In contrast, a vasodilating beta blocker was associated with a significant fall in ANF and BNF and a small rise in cardiac output. This study confirms both the advantages of vasodilating beta blockers over metoprolol for initial treatment of heart failure and the usefulness of ANF and BNF measurements for the assessment of drug effects in heart failure compared to traditional haemodynamic measurements.

Comparison of intensive and low-dose atorvastatin therapy in the reduction of carotid intimal–medial thickness in patients with coronary heart disease

Background: Intensive statin therapy has been shown to improve prognosis in patients with coronary heart disease (CHD). It is unknown whether such benefit is mediated through the reduction of atherosclerotic plaque burden. Aim: To examine the efficacy of high-dose atorvastatin in the reduction of carotid intimal–medial thickness (IMT) and inflammatory markers in patients with CHD. Design: Randomised trial. Setting: Single centre. Patients: 112 patients with angiographic evidence of CHD. Interventions: A high dose (80 mg daily) or low dose (10 mg daily) of atorvastatin was given for 26 weeks. Main outcome measures: Carotid IMT, C-reactive protein (CRP) and proinflammatory cytokine levels were assessed before and after therapy. Results: The carotid IMT was reduced significantly in the high-dose group (left: mean (SD), 1.24 (0.48) vs 1.15 (0.35) mm, p = 0.02; right: 1.12 (0.41) vs 1.01 (0.26) mm, p = 0.01), but was unchanged in the low-dose group (left: 1.25 (0.55) vs 1.20 (0.51) mm, p = NS; right: 1.18 (0.54) vs 1.15 (0.41) mm, p = NS). The CRP levels were reduced only in the high-dose group (from 3.92 (6.59) to 1.35 (1.83) mg/l, p = 0.01), but not in the low-dose group (from 2.25 (1.84) to 3.36 (6.15) mg/l, p = NS). A modest correlation was observed between the changes in carotid IMT and CRP (r = 0.21, p = 0.03). Conclusions: In patients with CHD, intensive atorvastatin therapy results in regression of carotid atherosclerotic disease, which is associated with reduction in CRP levels. On the other hand, a low-dose regimen only prevents progression of the disease.

A prospective study of elective stenting in unprotected left main coronary disease.

The standard treatment of left main coronary artery (LMCA) disease has been bypass surgery (CABG). Recent reports suggested that stenting of LMCA disease might be feasible. From January 1995 to April 1998, we carried out a prospective study of elective stenting of unprotected LMCA disease to evaluate its immediate and long‐term results. Of 61 consecutive patients with unprotected LMCA disease, 6 were excluded. Acute procedural success was 100% for the remaining 55 patients, without any complications such as stent thrombosis, myocardial infarction, CABG, or death. During a mean follow‐up of 16.1 ± 9.6 months, 11 patients (20%) had symptomatic recurrence, between 2 to 6 months after their procedure. Seven patients underwent CABG, two had repeat intervention, one continued with medical therapy, and one died before planned angiography. There was no late sudden death. Forty‐four patients (80%) remained asymptomatic. We conclude that elective stenting may be a safe alternative to CABG in unprotected LMCA disease. Cathet. Cardiovasc. Intervent. 46:153–159, 1999.

The effect of transcutaneous electrical nerve stimulation on coronary and systemic haemodynamics in syndrome X.

Background Neurostimulation techniques have been shown to be beneficial in patients with angina and syndrome X but the mechanism remains unclear. We examined the effect of transcutaneous electrical nerve stimulation (TENS) on coronary artery blood flow in a group of patients with syndrome X.Methods Coronary blood flows were measured in 11 patients with angiographically normal coronary arteries, positive results from exercise tests and angina (syndrome X) using intracoronary Doppler catheters combined with quantitative coronary angiography.Results The mean coronary flow velocity did not increase in any patient during TENS therapy; in fact, there was a fall from 5.2 ± 2.8 to 4.3 ± 1.9 cm/s (P= 0.02) and the coronary blood flow index fell from 47 ± 22 to 38 ± 16 cm/s per mm2 (P = 0.007). This was associated with a fall in the rate x pressure product from 0.92 ± 0.22 to 0.83 ± 0.18 mmHg/min (P = 0.038). The coronary vascular resistance rose from 2.4 ± 1.1 to 3.0 ± 1.6 mmHg/cm per s per mm2 (P= 0.041). There were no major changes in the epicardial coronary artery diameter during TENS and there was no significant efffect on the response to the cold-pressor test.Conclusions In this group of patients with syndrome X, TENS produced a small but significant fall in coronary artery blood flow associated with a reduction in the rate x pressure product. TENS had no significant effect on coronary vasomotion during sympathetic stimulation by the cold-pressor test. Thus, TENS is unlikely to have a direct effect on coronary artery vasomotion or haemodynamics in syndrome X but reduces the rate x pressure product and thus myocardial oxygen consumption.

The aetiology of heart failure in the Chinese population of Hong Kong - a prospective study of 730 consecutive patients *

Heart failure is a common and serious condition in many parts of the world and is a frequent cause for hospital admission in the Chinese population of Hong Kong. There is no published information on the epidemiology of heart failure in this community or from mainland China. Therefore, a prospective study of consecutive patients admitted with the clinical diagnosis of heart failure has been carried out to identify the main risk factors or possible causes, and other clinical data. Seven-hundred thirty consecutive patients with cardiac failure were identified and studied. Standard clinical criteria were used for diagnosis and identification of the main or most likely aetiologies and echocardiography was done in 30%. The data analysis of the 730 patients showed the following. The majority were females (56%) and the prevalence of heart failure increased with age (mean age 73.5 +/- 11.7 years) with 76% of the women > 70 years old. In contrast, the men were younger with 40% < 70 years old. The main identifiable risk factors were hypertension (37%), ischemic heart disease (31%), valvular heart disease (15%), cor pulmonale (27%), idiopathic dilated cardiomyopathy (4%), and miscellaneous (10%). In women, hypertension was the commonest cause at all ages but in men aged < 70 years ischemic heart disease was equal in frequency to hypertension (36% and 35%, respectively). Twenty-one percent had diabetes compared to a community rate of 10% for this age group (odds ratio 2.25, P < 0.0001). There was considerable overlap between diabetes, hypertension and ischemic heart disease. The estimated incidence rate was 3.8/1000 women and 3.0/1000 men aged > 45 years old.(ABSTRACT TRUNCATED AT 250 WORDS)

β Blockers in heart failure: a comparison of a vasodilating β blocker with metoprolol

Objective To determine whether a third generation vasodilating β blocker (celiprolol) has long term clinical advantages over metoprolol in patients with chronic heart failure. Design A double blind placebo controlled randomised trial. Setting University teaching Hospital. Patients 50 patients with stable chronic heart failure (NYHA class II-IV) due to idiopathic dilated, ischaemic, or hypertensive cardiomyopathy, with left ventricular ejection fraction < 0.45. Interventions Celiprolol 200 mg daily (n = 21), metoprolol 50 mg twice daily (n = 19), or placebo (n = 10) for three months with a four week dose titration period. After the double blind period, patients entered an open label study (with placebo group receiving β blockers) and were assessed after one year. Main outcome measures Clinical response, efficacy, and tolerance were assessed by the Minnesota heart failure symptom questionnaire, six minute walk test, Doppler echocardiography (systolic and diastolic function), radionuclide ventriculography, and atrial and brain natriuretic peptides measured at baseline and after three months. Results In the metoprolol group at 12 weeksv baseline there was a 47% reduction in symptom score (p < 0.001), improvement of NYHA class (mean (SEM), 2.6 (0.12) to 1.9 (0.13), p = 0.001), exercise distance (1246 (54) to 1402 (52) feet, p < 0.001), and left ventricular ejection fraction (26.9(3.1)% to 31(3.0)%, p = 0.016), and a fall in heart rate (resting, 79 (3) to 62 (3) beats/min, p < 0.001). In the celiprolol group there was a 38% reduction in symptom score (p = 0.02), less improvement in exercise distance (1191 (55) to 1256 (61) feet, p = 0.05), and no significant changes in NYHA class, left ventricular ejection fraction, or heart rate. Mortality at one year was 11% in metoprolol and 19% in the celiprolol group, and symptomatic improvement was maintained in the survivors. Conclusions Both drugs were well tolerated but the vasodilator properties of celiprolol do not seem to provide any obvious additional benefit in the long term treatment of heart failure.

Retrograde chronic total occlusion intervention: tips and tricks.

Retrograde approach via collateral channels in coronary angioplasty for chronic total occlusion (CTO) can improve the success rate. Most interventionists will meet a few cases where the retrograde approach will provide unequaled advantages, but many are held back from taking retrograde approach by lack of proper equipment and expertise. In this article, we give detail description of techniques to shorten the guiding catheter, to traverse the collateral channels, and to cross the CTO. We also illustrate the difficulties in collateral channel crossing with different examples providing a basic guide for case selection purposes. We hope that many others would find rewardingly successful cases of retrograde approach CTO percutaneous coronary intervention, as in our experience.

Endothelium-Dependent Dilation of the Coronary Arteries in Syndrome X: Effects of the Cold Pressor Test

The coronary flow reserve is abnormal in syndrome X, but the response to the cold pressor test, which in normals produces flow-mediated endothelium-dependent epicardial coronary dilation, has not been studied. In this study, in 12 patients with typical syndrome X and angiographically normal coronary arteries, the response to the cold pressor test was abnormal with a mean fall in diameter (10 +/- 8%) in 6 patients, no change in 1, and a minimal increase (4 +/- 2%) in 5 patients (normal increase 12 +/- 1%). The coronary blood flow fell slightly during the cold pressor test, and the coronary vascular resistance increased significantly (from 2.4 +/- 1.1 to 3.2 +/- 1.7 mm Hg/cm.s-1.mm2; p = 0.05), both abnormal responses. This study confirms that in syndrome X patients there is coronary endothelial dysfunction which is apparent in response to physiological stimuli induced by the cold pressor test.

Left main stem rupture caused by methicillin resistant Staphylococcus aureus infection of left main stent treated by covered stenting

Coronary artery infection after angioplasty or stent implantation is a rare and dreaded complication of percutaneous coronary intervention. 80% of the cases are due to Staphylococcus aureus. About half the cases lead to rupture or perforation of the coronary artery while the other half presents as abscesses or aneurysms. Surgical treatment is the conventional therapeutic modality but it carries a high mortality. We report a case of a high risk patient who had methicillin resistant Staphylococcus aureus infection of left main stem stent leading to rupture and pseudoaneurysm formation that is successfully treated with stent graft.