Atheroembolic occlusion of the left axillary artery after percutaneous transluminal coronary angioplasty.
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Angioplasty, Balloon, Coronary↗
Biomedical subjects
F T Chiang
Publications and source records attributed to F T Chiang.
Congenital mitral stenosis: challenge of percutaneous transvenous mitral commissurotomy.
A 26-year-old woman with congenital mitral stenosis and embolic stroke was referred to our hospital. The echocardiogram showed a hypoplastic posterior mitral valve leaflet with short, unbalanced chordal attachments to the posteromedial papillary muscle. The mitral valve area was 0.9 cm2 by the pressure half-time method. There was no left atrial thrombus and spontaneous echo contrast. Percutaneous transvenous mitral commissurotomy was performed since the suggestion of surgical management was refused by her family members. A rupture at the chordae tendinae of the hypoplastic posterior papillary muscle developed during the procedure and needed mitral replacement. We advise that percutaneous transvenous mitral commissurotomy be avoided in adult patients with congenital mitral stenosis having an asymmetric and hypoplastic mitral valve.
Adult↗
Insertion/deletion polymorphism of the angiotensin I-converting enzyme gene in patients with hypertension, non-insulin-dependent diabetes mellitus, and coronary heart disease in Taiwan.
An insertion/deletion (I/D) polymorphism of the angiotensin I-converting enzyme (ACE) gene has been identified that determines most of the plasma ACE activity genetically. Association of the D allele with insulin sensitivity and of the D/D genotype with coronary heart disease (CHD) has been reported in various ethnic populations. To study the role of this genetic polymorphism in patients with hypertension, non-insulin-dependent diabetes mellitus (NIDDM), and NIDDM with CHD in a Taiwanese population, we used a polymerase chain reaction (PCR)-based genotyping technique with an insertion-specific primer for confirmation of the I allele. One hundred ninety-seven unrelated normal controls, 67 subjects with hypertension, 107 subjects with NIDDM, and 70 subjects with NIDDM and CHD were recruited for this study; all were Han Chinese. Subjects without a history of diabetes were studied by a standard 75-g oral glucose tolerance test. Hypertension was diagnosed according to the Fifth Joint National Committee criteria, and CHD was confirmed by a history of acute myocardial infarction and coronary angiographic intervention. The frequency of the I allele of the ACE gene in the normal population was 64.2%, which was higher than reported in white populations. The prevalence of the I allele of the ACE gene was not significantly increased in subjects with hypertension (73.1%), NIDDM (62.1%), and NIDDM with CHD (65%) compared with healthy controls. The I allele of the ACE gene did not correlate with demographic and metabolic variables. I/D polymorphism of the ACE gene is not a marker for hypertension, NIDDM, or CHD in this Taiwanese population.
Age of Onset↗
Lack of association of the angiotensin converting enzyme polymorphism with essential hypertension in a Chinese population.
To examine the association between insertion/deletion (I/D) polymorphism of the angiotensin converting enzyme (ACE) gene and essential hypertension in a Chinese population, a case-control study was conducted using 157 hypertensive and 115 normotensive subjects. The I/D polymorphism of the ACE gene was identified by polymerase chain reaction. Plasma ACE activity was determined using spectrophotometry. The difference of allele frequencies between normotensives and hypertensives was statistically significant (chi 2 = 4.467, P = .035), while the genotype distribution was not different between normotensive and hypertensive subjects (chi 2 = 3.954, P = .138). Plasma ACE activity was highest in the DD genotype, followed by the ID genotype, and the lowest in the II genotype (P = .0001 in normotensives and P = .163 in hypertensives, respectively). Thus, we conclude that the ACE gene polymorphism is not associated with essential hypertension in this Chinese population, but plasma ACE activity is genetically determined in the normotensive Chinese.
Adult↗
Nucleotide(-258) G-to-A transition variant of the liver glucokinase gene is associated with essential hypertension.
Hypertension is a complex disease with strong genetic influences. Essential hypertension has been shown to be associated with insulin resistance. A molecular variant with G-to-A transition at the nucleotide -258 of the liver glucokinase (GCK) promoter was found in diabetic patients. The variant A allele is associated with insulin resistance. We examine the role of this genetic variant in the pathogenesis of hypertension using a population association study. We recruited 205 Taiwanese subjects and they were divided into two groups based on either presence (65 subjects) or absence (140 subjects) of essential hypertension. Genomic DNA was extracted from peripheral leukocytes. Genotypes at this locus were determined by using a polymerase chain reaction restriction fragment length polymorphism. The distribution of genotypic frequency was different between the hypertensive and control groups (P = .009). The frequency of variant A allele was greater in hypertensive subjects than in control (23% v 10%, P = .001). Subjects with at least an A allele had a risk for hypertension by 2.52 times (95% confidence interval 1.29 to 4.91) as compared with those without an A allele. Thus, we first demonstrate the association between the G-to-A variants at the nucleotide -258 of the liver GCK gene and essential hypertension. This may explain the insulin resistance in essential hypertension and the variant A allele as a risk factor for essential hypertension in the Taiwanese population.
Alleles↗
Electrophysiological properties in patients undergoing atrial compartment operation for chronic atrial fibrillation with mitral valve disease.
AIMS: Surgical treatment for atrial fibrillation is now feasible in selective cases. The aim of this study was to assess the electrophysiological properties of patients undergoing atrial compartment operation for chronic atrial fibrillation. METHODS AND RESULTS: Electrophysiological studies were performed in 20 mitral valve patients with atrial fibrillation who had been maintained in sinus rhythm for more than 1 year after atrial compartment operation. Intra-cardiac recording and programmed electrical stimulation were performed in various atrial compartments. The parameters studied included sinus node function, atrial conduction and refractoriness, atrioventricular conduction function and inducible arrhythmias if any. Intra-cardiac recordings showed that the rhythm was of sinus origin in all cases, with the earliest atrial activity located in the high right atrium. The mean sinus cycle length was 750 +/- 110 ms, AH time 106 +/- 29 ms, and HV time 53 +/- 7 ms. The sinus node function was normal in 18 patients (90%), and only two patients had prolonged sinus node recovery and sino-atrial conduction. The right atrial appendage compartment was driven by the sinus node in all patients. However, the conduction time from the high right atrium to the right atrial appendage compartment was markedly prolonged in 12 of 15 patients (80%) undergoing the three-compartment operation in which an incision was placed between the high right atrium and right atrial appendage compartments. On the other hand, the electrical activities in the left atrial compartment were much more varied. In 13 of 20 patients (65%), the left atrial compartment was driven by the sinus node; 11 of the 13 patients had a normal or mildly prolonged conduction time (ranged 75 to 146 ms), whereas two patients had a marked delay in conduction (200 ms and 266 ms, respectively). In the remaining seven patients, the left atrial compartments were dissociated from the rest of the heart; five of them had a quiescent left atrium, one a fluttering left atrial rhythm, and one a slow left atrial rhythm. The effective refractory period was longer in the left atrial compartment (242 +/- 47 ms) as compared to that of the high right atrium (224 +/- 26 ms, P < 0.01) and right atrial appendage compartments (219 +/- 25 ms, P < 0.01). Programmed electrical stimulation could not induce atrial fibrillation in any patient, whereas two patients had inducible atrial flutter and three repetitive atrial responses. CONCLUSIONS: (1) Atrial compartment operation does not impair sinus node function in most cases. (2) Elimination of atrial fibrillation while maintaining the electrical connection between different atrial compartments is feasible.
Adolescent↗
Molecular variant M235T of the angiotensinogen gene is associated with essential hypertension in Taiwanese.
OBJECTIVE: To examine the association of the molecular variants of the angiotensinogen (AGT) gene with essential hypertension in Taiwanese. METHODS: We conducted a case-control study concerning 151 subjects, 102 hypertensives and 49 normotensives. We created a rapid mini-sequencing method based on dye-terminator cycle sequencing to simultaneously detect the M235T and T174M variants of the AGT gene for each subject. RESULTS: The genotype and allele distribution of the M235T variant differed significantly in hypertensives and normotensives (chi 2 = 11.106, P = 0.004 and chi 2 = 6.453, P = 0.011, respectively), whereas those of the T174M variant did not differ (chi 2 = 0.004, P = 0.998 and chi 2 = 0.032, P = 0.858, respectively). The odds ratio for hypertension was 3.64 (95% confidence interval 1.56-8.49) for subjects with the C/C genotype of the M235T variant compared with other genotypes of 2.87 (95% confidence interval 1.76-4.68) for those carrying allele C versus those carrying allele T. CONCLUSION: The molecular variant M235T, but not T174M, of the AGT gene is associated significantly with essential hypertension in this Taiwanese population. The genotype C/C or allele C is a risk factor for hypertension. The underlying mechanism of this association needs to be elucidated further.
Adult↗
Association of the renin gene polymorphism with essential hypertension in a Chinese population.
To study the association of renin gene polymorphism with essential hypertension in the Chinese population, 86 hypertensive and 107 normotensive subjects were enrolled from an epidemiologic survey. Leukocyte DNA was extracted and digested with Hind III and Bgl I restriction enzymes. Southern hybridization was done with digoxigenin-incorporated renin gene probes generated by polymerase chain reaction. The restriction fragments were detected by anti-digoxigenin antibody and enzyme methods. Two Hind III polymorphysms of the renin gene (8.7 kb and 6.2 kb) were identified. The allele frequences were 129(75%) and 43(25%), respectively, in hypertensives; they were 139(65%) and 75(35%), respectively, in normotensives (chi2 = 4.074, p = 0.044). The genotypes of 8.7/8.7,8.7/6.2 and 6.2/6.2 were significantly different between hypertensives and normotensives, being 45(52%), 39(45%), 2(3%) and 48(45%), 43(40%), and 16(15%), respectively (chi2 = 9.002, p = 0.11). The Bgl I polymorphism did not show a difference between hypertensives and normotensives. Thus, we conclude that the renin gene Hind III polymorphysm is associated with hypertension in this Chinese population.
Adult↗
Lack of association between angiotensin-converting enzyme gene polymorphism and coronary heart disease in a Chinese population.
Insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene has been postulated as a risk factor for coronary heart disease. We conducted a case-control study of 271 Chinese, including 114 subjects with coronary artery disease (CAD), 42 with non-CAD and 115 apparently normal controls to examine the association of I/D polymorphism and CAD. The genotypes were identified by polymerase chain reaction and the plasma ACE activity was assayed by spectrophotometry. The allele and genotype frequencies were not different among the CAD, non-CAD and apparently normal groups (p = 0.42 and 0.63). Plasma ACE activity was not different among the three groups (p = 0.32). The D-allele and DD genotype were not more prevalent in subjects with low risk CAD (p = 0.07 and 0.16) and subjects with myocardial infarction (p = 0.79 and p = 0.35). No association was found between I/D polymorphism and severity of CAD (p = 0.42 and 0.70). In conclusion, the deletion polymorphism of the ACE gene may not be an independent risk factor in the development of CAD or myocardial infarction in this Chinese population. The unique or synergistic effect of other genes needs further study.
Aged↗
Cardiac contractility in noninsulin dependent diabetes mellitus evaluated using the relation between endsystolic wall stress and velocity of circumferential fiber shortening.
The relation between left ventricular (LV) endsystolic wall stress (sigma es) and rate-corrected velocity of circumferential fiber shortening (Vcfc), which is independent of heart rate (HR) and loading conditions has previously been used to assess cardiac contractility in insulin dependent diabetes mellitus (IDDM). This study is the first report in which this relation has been utilized with data obtained by echocardiography in addition to the traditional indices, to evaluate the cardiac function in asymptomatic, middle-aged patients with noninsulin dependent diabetes mellitus (NIDDM) at baseline and during dobutamine stimulation. There were 16 NIDDM patients in our study and these patients were classified into 2 groups. Group 1 consisted of 11 patients without microvascular complications. Group 2 consisted of the remaining 5 patients with microvascular complications. Ten age- and sex-matched normal subjects were enrolled as a control group. At baseline, diabetic patients tended to have a faster HR and a greater LV enddiastolic dimension, though these values were not significantly different from the normal subjects. Ejection fraction (EF) in group 1 was significantly higher than that of the normal controls (73 +/- 2% vs 65 +/- 2%, p < 0.005). Mitral inflow pattern was normal (E/A > 1) in the normal subjects (1.11 +/- 0.06), but reversed in group 1 (0.87 +/- 0.07) and group 2 (0.95 +/- 0.12). Isovolumic relaxation time corrected for HR (IVRTc) and the slope of relation between sigma es and Vcfc were similar among the 3 groups. Comparing Vcfc at 50 g/cm2 of sigma es, it tended to increase from the normal subjects (0.883 +/- 0.057 cir/sec) to 0.969 +/- 0.048 in group 1 and 1.034 +/- 0.101 in group 2, though this result was not statistically significant. During dobutamine stimulation, EF increased and IVRTc shortened significantly only in the normal subjects. E/A became normalized in both diabetic groups. The increment in Vcfc representing cardiac reserve of contractility was significantly lower in the diabetics (0.110 +/- 0.040 in group 1 and 0.057 +/- 0.043 in group 2) than in normal subjects (0.244 +/- 0.044). In conclusion, using the index of relation between sigma es and Vcfc, the cardiac contractility of NIDDM was not impaired at baseline, and even had a tendency to increase. However, during dobutamine stimulation, the inadequate reserve of contractility was exposed, especially in those patients who had microvascular complications. These results indicate the importance of controlling diabetes, not only to prevent the development of microvascular complications but also to preserve cardiac function.
Adrenergic beta-Agonists↗
Myocardial mechanics and titin in experimental insulin-resistant rats.
We investigated the intrinsic cardiac mechanics of myocardium and changes in titin in insulin-resistant rats. Microsonometry and micromanometry were used to evaluate the maximal elastance (Emax) and myocardial stiffness constant (Km) of the left ventricle, in addition to the traditional systolic and diastolic cardiac function, with an isolated working heart preparation. Thirty 150 g Wistar rats were divided into three groups of 10. Group A was fed rat chow, while groups B and C were fed a 66% fructose diet for 7-8 months. Group C also received clonidine. Group B rats developed insulin resistance, as well as elevated plasma glucose and blood pressure. Group C rats also had insulin resistance and elevated plasma glucose, but not higher blood pressure. Group B rats had decreased Emax, decreased peak-dp/dt, prolonged Tau and increased Km compared to normal control rats. Group C rats, which mimicked the clinical condition of diabetic cardiomyopathy, maintained normal global left ventricular function as revealed by cardiac output, peak + dp/dt, peak-dp/dt and Tau of relaxation. However, they had a lower Emax slope (355 +/- 51 vs 535 +/- 56 mmHg.mm than group A rats, p < 0.05) and increased Km (81.6 +/- 9.9 vs 25.5 +/- 4.8 in group A, p < 0.001), even though the extent of elevation of plasma glucose was only mild (71.3 +/- 2.0 to 108.9 +/- 4.4 mg/dl, p < 0.001). Their left ventricular mass, myocyte size, interstitial fibrosis and vascular picture did not change. However, the content of myocardial titin decreased significantly (intensity ratio of titin/actin was 0.23 +/- 0.01 and 0.29 +/- 0.02 in group C and group A rats respectively, p < 0.05). These findings suggest that changes in titin play a role in the change in myocardial functional characteristics and may be one of the causes of diabetic cardiomyopathy.
Animals↗
Penetration of the interatrial septum: a rare complication of percutaneous transluminal mitral commissurotomy.
Interatrial septal dissection and penetration into the aorta by a balloon catheter occurred in a 38-year-old man with mitral stenosis as a complication of percutaneous transluminal mitral commissurotomy during trans-septal puncture. It was speculated that the thickened septum was partially punctured into the potential space between the septa primum and secundum. Then, the balloon catheter went through the interatrial septum dissection into the aortic root. Emergency surgery was performed with the catheter left in situ. The surgical findings confirmed the speculated mechanism of this rare complication. In order to avoid this complication, the location of the tip of the Brockenbrough catheter after transeptal puncture must be confirmed. Checking the left atrial pressure tracing, arterial oxygenation and contrast injection are all important and indispensable procedures.
Adult↗
Abnormal circadian blood pressure changes in patients with acute cerebrovascular disorders.
The central neural mechanisms of circadian rhythm are well known in animal models but less so in humans. In this study we looked for correlations between abnormalities of circadian rhythm and the sites of stroke, with the aim of identifying the location regulating the circadian rhythm in humans. We investigated the circadian profiles of arterial pressure in 100 stroke patients by ambulatory blood pressure monitoring within 2 days after their first stroke. Patients also underwent brain computed tomography and measurements of plasma norepinephrine and adrenal hormones. A total of 52 patients (group A) had abnormal patterns of circadian blood pressure rhythm while 48 patients had normal patterns (group N). The risk of an abnormal 24-hour blood pressure pattern was strongly inversely correlated with the distance between the lesion and the hypothalamus. There was also a close positive correlation between the distance from the lesion to the hypothalamus and the circadian indices of arterial blood pressure (systolic and diastolic pressure) in both groups. Abnormal circadian changes in adrenal hormones were found in 30 of 52 patients in group A, and in nine of 48 patients in group N. Apparently, the circadian rhythm of blood pressure is modulated mainly by direct neural effects and partly by the hormonal effects of the hypothalamus and its associated neural pathways. Individualized antihypertensive treatment and additional monitoring for possible cardiac events should be performed for those at a high risk of autonomic dysfunction.
Acute Disease↗
The mechanism of sympathovagal imbalance in patients with myocardial ischemia.
To investigate the mechanism of sympathovagal imbalance due to myocardial ischemia, we studied 42 consecutive patients undergoing successful percutaneous transluminal coronary angioplasty by correlating frequency domain and time domain measures of heart rate variability with parameters such as echocardiography, stress thallium scanning and radionuclide angiography before, immediately after and 2 months after the procedure. Of these, 20 patients (Group N) had normal and 22 patients (Group A) had abnormal regional wall motion. A control group of 20 healthy subjects (Group C) underwent echocardiography and examination of heart rate variability twice at 2-month intervals to check for spontaneous variations. At baseline, frequency domain measures such as low and high frequency power and time domain measures such as SDANN index (the mean of the standard deviations of the average of RR intervals) were lower in Group A than in Groups N and C, whereas no differences were detectable in ultra low and very low frequency, total power, SDNN index (the mean of the standard deviations of the mean of normal RR intervals), and r-MSSD (the root mean square of successive RR differences). There was high association between the diastolic wall stress index and both high frequency (r = -0.82) and low frequency power (r = -0.77). There were similar findings for the systolic wall stress index (r = -0.72 for high frequency and r = -0.64 for low frequency power). After successful coronary angioplasty, regional wall motion, left ventricular wall stress indices and all measures of heart rate variability were unchanged in Group N. In Group A the mean summed segment score improved from 15.9 +/- 2.6 to 12.2 +/- 1.7 (p < 0.0001), and mean low frequency, mean high frequency power (logarithmic units), and SDANN index (msec) increased from 6.10 +/- 0.23 to 6.36 +/- 0.28 (p < 0.005), from 5.36 +/- to 0.40 to 5.70 +/- 0.39 (p < 0.01) and from 70 +/- 18 to 83 +/- 18 (p < 0.01) respectively. In addition, low and high frequency power and SDANN index, lower at baseline in Group A than in the other two groups, were comparable in the three groups after coronary angioplasty. The evolution of diastolic and systolic wall stress indices paralleled that of the above three parameters. In conclusion, diastolic and systolic wall stress indices, in addition to segmental left ventricular dysfunction, were synergistically involved in determining sympathovagal imbalance in patients with significant coronary artery disease; the reversal of left ventricular dysfunction and wall stress indices improves the profile of heart rate variability. Alterations in cardiac geometry and wall stress influence mainly the discharge of afferent sympathetic and efferent parasympathetic innervations and also principally the long-term heart rate variations instead of short-term modulation.
Angioplasty, Balloon, Coronary↗
The cause-effect relationship of sympathovagal activity and the outcome of percutaneous transluminal coronary angioplasty.
We studied 25 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) to determine the association of sympathovagal imbalance and the outcome of coronary angioplasty. We examined the profiles of heart rate variability (HRV) using echocardiography, stress thallium scanning and radionuclide angiography before, immediately after and 1 month after the procedure. Coronary angiography was followed up at 6 months or if restenosis was suspected, to determine whether restenosis had occurred. Frequency domain (LF/HF) and time domain (SDNN, SDANN-ind, and r-MSSD) parameters were analyzed. According to the evolution of each parameter, we classified the patients into Group Ax (improved in HRV profile) and Group Bx (deteriorated in HRV profile) [x = 1 for LF/HF, 2 for SDNN, 3 for SDANN-ind, and 4 for r-MSSD]. We found that there was no definite association between Gensini score and HRV profiles at the baseline for each group. No significant changes existed between the HRV profiles before and immediately after PTCA. For the LF/HF ratio, 5 of 11 in Group B1 had restenosis while 0 of 14 in Group B2 and 1 of 19 in Group A2 had restenosis (p < 0.01). There were no significant predictive values for SDANN-ind and r-MSSD (p = 0.12 and 0.07, respectively). We conclude that the sympathovagal imbalance did not reflect the severity in coronary artery disease but was associated with restenosis after successful PTCA.
Aged↗
Atrial natriuretic peptide gene polymorphism is not associated with essential hypertension: evidence of association with ethnic origin.
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Atrial Natriuretic Factor↗
Ambulatory blood pressure monitoring for evaluation of long-acting beta-blockers in Taiwan.
This study attempted to evaluate the efficacy of several "long-acting" antihypertensive agents. One-hundred consecutive hypertensive subjects with normal casual blood pressure after once-daily antihypertensive monotherapy treatment were studied. They were divided into three groups: group A, metoprolol (100 mg, daily); group B, atenolol (100 mg, daily); and group C, nadolol (80 mg, daily). Ambulatory blood pressure monitoring (ABPM) was used to evaluate the efficacy of the antihypertensive agents. The overall average ambulatory blood pressures were within the normal limits for all three groups. However, there were some abnormally high blood pressure (BP) readings shown on ABPM. Patients with an abnormally high systolic blood pressure (SBP) average > 140 mmHg accounted for 16.7% of group A, 19.4% of group B and 20% of group C. Those with an abnormally high diastolic blood pressure (DBP) average > 90 mmHg accounted for 16.7%, 19.4% and 10%, respectively, of the corresponding groups. There were no significant differences in the frequency of abnormally high SBP and DBP among the three groups. These "long-acting" antihypertensive drugs did not effectively control BP throughout the entire day. The duration of antihypertensive effect is not necessarily reflected by the blood half-life of the drug. ABPM is an effective way to ascertain the efficacy of "long-acting" hypertensive agents.
Adrenergic beta-Antagonists↗
Coronary artery perforation and delayed cardiac tamponade following balloon coronary angioplasty.
A 62-year-old woman who had coronary artery disease and hypertrophic cardiomyopathy received percutaneous transluminal coronary angioplasty and endomyocardial biopsy. She withstood the procedure well. However, delayed pericardial tamponade occurred 2 hours after discharge from the cardiac catheterization laboratory. Despite pericardial drainage with a pigtail catheter and blood transfusion, the patient required emergency surgery. An oozing diagonal branch of the left anterior descending coronary artery was found. Ligation of this small branch stabilized the hemodynamics. Avoidance of improper positioning of the guide wire in the small coronary artery branch is important in preventing arterial wall trauma and subsequent perforation.
Angioplasty, Balloon, Coronary↗