Changing patterns in medication prescription for gestational diabetes during a time of guideline change in the USA: a cross-sectional study

OBJECTIVE

To define patterns of prescription and factors associated with choice of pharmacotherapy for gestational diabetes mellitus (GDM), namely metformin, glyburide and insulin, during a period of evolving professional guidelines.

DESING

Cross-sectional study.

SETTING

US commercial insurance beneficiaries from Market-Scan (late 2015 to 2018).

STUDY DESIGN

We included women with GDM, singleton gestations, 15-51 years of age on pharmacotherapy. The exposure was pharmacy claims for metformin, glyburide and insulin.

MAIN OUTCOMES

Pharmacotherapy for GDM with either oral agent, metformin or glyburide, compared with insulin as the reference, and secondarily, consequent treatment modification (addition and/or change) to metformin, glyburide or insulin.

RESULTS

Among 37 762 women with GDM, we analysed data from 10 407 (28%) with pharmacotherapy, 21% with metformin (n = 2147), 48% with glyburide (n = 4984) and 31% with insulin (n = 3276). From late 2015 to 2018, metformin use increased from 17 to 29%, as did insulin use from 26 to 44%, whereas glyburide use decreased from 58 to 27%. By 2018, insulin was the most common pharmacotherapy for GDM; metformin was more likely to be prescribed by 9% compared with late 2015/16, but glyburide was less likely by 45%. Treatment modification occurred in 20% of women prescribed metformin compared with 2% with insulin and 8% with glyburide.

CONCLUSIONS

Insulin followed by metformin has replaced glyburide as the most common pharmacotherapy for GDM among a privately insured US population during a time of evolving professional guidelines. Further evaluation of the relative effectiveness and safety of metformin compared with insulin is needed.

TWEETABLE ABSTRACT

Insulin followed by metformin has replaced glyburide as the most common pharmacotherapy for gestational diabetes mellitus in the USA.

OS053. Trophoblast invasion in the mesometrial triangle of atp infused pregnant rats

INTRODUCTION

Poor placentation (disturbed and decreased trophoblast invasion) is a hallmark of preeclampsia (PE), which is a major complication of pregnancy. Unfortunately, the cause and mechanism of disturbed trophoblast invasion is still unknown.

OBJECTIVES

The pro-inflammatory agent ATP has been shown to induce PE-like signs, after a single infusion in pregnant rats. These PE-like characteristics include proteinuria and decreased fetal weight. Since purinergic ATP receptors are expressed on trophoblast cells, we aimed to study the effect of ATP infusion on trophoblast invasion in pregnant rats in this pilot study.

METHODS

Pregnant rats received a single ATP (n=4) or saline (control,ni=5) infusion via a permanent jugular vein cannula on day 14 of pregnancy. At the time of maximal trophoblast invasion (day 17 of pregnancy) rats were sacrificed and placentas with mesometrial triangle were collected, fixed in zinc-buffer and embedded in paraffin. 4 μm sections were stained with monoclonal α-cytokeratin antibodies. In the mesometrial triangle, the maternal part of the rat placenta, the percentage of surface area of trophoblast invasion was evaluated using computerized image analysis. Also, the depth and width of invasion were analyzed by subdividing the mesometrial triangle in three concentric depth levels of equal width. In addition, trophoblast invaded versus non-invaded spiral arteries in the mesometrial triangle were quantified.

RESULTS

In the mesometrial triangle, no changes in percentage of surface area of trophoblast invasion and percentage of invaded spiral arteries were observed after ATP infusion. However, the pattern of trophoblast invasion appeared to be disturbed in ATP infused rats, with a decreased depth of invasion and an increased width of invasion, resulting in a trend towards a decreased depth/width ratio of trophoblast invasion in ATP infused rats.

CONCLUSION

In this (pilot) study we showed an altered trophoblast invasion pattern in the mesometrial triangle of the placenta, although no significant differences in the total surface area of trophoblast invasion were seen in experimental versus control pregnant animals. e mechanism by which ATP induces this altered trophoblast invasion pattern and its potential contribution to the pathophysiology of this experimental PE in the pregnant rat awaits further investigation.

Three-dimensional analysis of post-caloric nystagmus caused by postural change

In order to record caloric nystagmus (CN) using three-dimensional videonystagmography (3D VNG) 14 subjects were placed in the supine position with the head tilted up 30 degrees relative to the earth's horizontal plane. After the primary-phase CN had terminated, the subjects were repositioned from a supine to a sitting position, with the head anteflexed 30 degrees for recording the post-caloric nystagmus (PCN). In addition, 8 of the original subjects were placed in the supine position but with the head turned 40 degrees to the left so that the irrigated (right) ear was oriented upwards. After the primary-phase CN had terminated, the subjects were rotated by 180 degrees so that the irrigated ear was oriented downwards to record PCN. The results indicated that both methods successfully provoked horizontal and vertical CN. For torsional CN, the irrigated ear up/down method produced a higher provocation rate (75%) than the supine/sitting method (50%), but the difference was not significant. Comparing the provocation rate of the PCN for the horizontal component revealed that the two methods do not differ significantly. However, when comparing the provocation rates of PCN for the vertical component, the irrigated ear up/down method showed a higher rate (82%) than the supine/sitting method (18%). Thus using 3D VNG coupled with postural change during caloric testing, the horizontal or vertical components of PCN can be successfully provoked.

Multicentricity of intraparotid facial nerve schwannomas

Facial nerve schwannomas are uncommon neoplasms. Multiple schwannomas of the facial nerve in the parotid region are rare. Research regarding the pathogenesis of multiple facial nerve schwannomas is incomplete. Both the neoplastic bridging of tumor cells and tumor multicentricity have been hypothesized. We present a case of multiple intraparotid facial nerve schwannomas. In this case, the histologic features of the tumors support the multicentric hypothesis.

BAD/BCL-[X(L)] heterodimerization leads to bypass of G0/G1 arrest

The pro-apoptotic molecule BAD binds BCL-[X(L)] or BCL2 and inactivates their survival function. In addition to their anti-apoptotic function, BCL2 and BCL-[X(L)] also delay cell cycle entry from quiescence. We found that the BH3-only molecule BAD also exerted a cell cycle effect. BAD expression resulted in failure to cell cycle block in growth arrest conditions. In low serum and in confluence, fibroblasts constitutively or inducibly expressing BAD persisted in S phase, continued to incorporate BrdU, and exhibited sustained cyclin E/cdk2 activity. Mutation analysis indicated that the cell cycle effect of BAD was not dependent on its phosphorylation status or subcellular localization, but strictly co-segregated with BCL-[X(L)] binding. bclx(-/-) MEFs expressing BAD and bad(-/-) MEFs both arrested in G0/G1 in low serum similar to wild-type controls, suggesting that the ability to overcome the G0/G1 checkpoint resulted from the presence of BAD/BCL-x(L) heterodimers, rather than the absence of BCL-[X(L)] or BAD. These data provide evidence that in addition to regulating apoptosis, the BAD/BCL-[X(L)] heterodimer has a novel cell cycle function.

Unusual electrocardiographic manifestations in acute isolated right ventricular infarction

Electrocardiographic (ECG) manifestation of ST-segment elevation in the precordial leads during acute myocardial infarction is usually due to anterior myocardial infarction secondary to occlusion of the left coronary artery. Herein, we reported a rare case of isolated right ventricular infarction (RVI) in which the ECG mimicked that of acute anterior left ventricular infarction (LVI). A 64-year-old man had acute isolated RVI documented by positive cardiac enzymes and echocardiographic and angiographic findings. He developed hypotension. His ECG showed ST-segment elevation in the precordial leads V1 to V3 simulating that of acute anterior wall infarction. Coronary angiogram revealed total occlusion of the proximal right coronary artery with well-established collaterals from the left coronary artery to the posterior descending artery. This case report reminds us that the presence of diffuse ST-segment elevation in the precordial leads could be due to acute isolated RVI rather than acute anterior LVI. The differentiation of these two entities is important, as their therapies are quite different.

Proteolysis of integrin α5 and β1 subunits involved in retinoic acid-induced apoptosis in human hepatoma Hep3B cells

Our previous report demonstrated that all-trans-retinoic acid (ATRA) induces detachment and death under serum starvation in several human tumor cell lines. In this study, we examined the influence of cell-extracellular matrix interaction on the ability of ATRA to induce apoptosis. Plating of human hepatoma Hep3B cells onto poly-hydroxyethylmethacrylate-coated plates in the absence of serum resulted in the acceleration of ATRA-induced apoptosis. In contrast, ATRA-induced apoptosis was significantly suppressed by plating cells onto Matrigel-coated plates but not suppressed by culturing onto collagen-, laminin-, vitronectin-, or fibronectin-coated plates. Exogenously added soluble collagen, laminin, fibronectin, vitronectin or Matrigel failed to suppress ATRA-induced apoptosis. Results from the adhesion assay indicated that the cell attachment to fibronectin was significantly inhibited by ATRA. Treatment with perturbing antibody against integrin alpha5 or beta1 subunits resulted in promotion of ATRA-induced apoptosis. Moreover, the proteolytic cleavage of alpha5beta1 integrin and focal adhesion kinase (FAK) proteins is linked to the early phase of the ATRA-induced apoptotic process. Furthermore, ATRA-induced detachment, death, and cleavage of alpha5beta1 integrin and FAK were drastically suppressed by plating cells onto Matrigel-coated plates. These findings provide evidence that abrogation of cell adhesion, through proteolysis of alpha5beta1 integrin and FAK, is closely linked to ATRA-induced apoptosis in Hep3B cells.

Importance of hyperhomocysteinemia as a risk factor for venous thromboembolism in a Taiwanese population. A case-control study

OBJECTIVE

To determine the current status of hyperhomocysteinemia, which is a known risk for venous thrombosis (DVT), in Taiwan.

SUBJECTS

101 unselected patients with a minimum of one episode of deep leg DVT, either initial inpatients or current compliant outpatients in a teaching hospital.

METHODS

Various thrombophilic risks, gene polymorphism and clinical predisposition were evaluated.

RESULTS AND CONCLUSIONS

Patients presented higher fast total plasma homocysteine (hcy) levels than age- and sex-matched controls did (14.1 vs. 9.94 microM). Based on the 95th percentile of control values, hyperhomocysteinemia had a four- to nine-fold risk for DVT, irrespective of clinical predisposition, as well as other thrombophilic risks surveyed. Polymorphism of a metabolizing enzyme, methylenetetrahydrofolate reductase (MTHFR), was not associated with DVT, although homozygous thermolabile mutation tended to have higher plasma hcy levels. Factor V Leiden was absent in analysis of 80 patients. In complete evaluation (hcy, antithrombin (AT), protein S (PS), protein C (PC), lupus anticoagulant (LA), anticardiolipin antibody) of a subset of 83 patients hyperhomocysteinemia was the most prevalent risk (33.7%), with PC or PS deficiencies following (22.9%). Thus, hyperhomocysteinemia is a prominent risk for DVT in Taiwan.

Protein phosphatase 2A activates the proapoptotic function of BAD in interleukin- 3-dependent lymphoid cells by a mechanism requiring 14-3-3 dissociation

BAD is a proapoptotic member of the BCL-2 family of proteins, which play a major role in regulating apoptosis in cytokine-dependent hematopoietic cells. The function of BAD is regulated by reversible phosphorylation. Deprivation of survival factors induces BAD dephosphorylation, resulting in apoptosis. Serine-threonine phosphatase activity dephosphorylated BAD in interleukin-3-dependent FL5.12 lymphoid cells. Inhibition of PP2A activity by treatment of cells with PP2A-selective inhibitors, okadaic acid and fostriecin, prevented BAD dephosphorylation in these cells. Conversely, BAD dephosphorylation was not inhibited by the PP1-selective inhibitor tautomycin. In cell-free extracts, BAD phosphatase activity was also inhibited by the PP2A-selective inhibitors okadaic acid and fostriecin, but not by the PP1-specific protein inhibitor I-2. Dissociation of 14-3-3 from BAD was a prerequisite for BAD dephosphorylation in vitro, suggesting a mechanism by which 14-3-3 can regulate the activation of the proapoptotic function of BAD in vivo. Significantly, the inhibition of BAD phosphatase activity rescued cell death induced by survival factor withdrawal in FL5.12 cells expressing wild-type BAD but not phosphorylation-defective mutant BAD. These data indicate that PP2A, or a PP2A-like enzyme, dephosphorylates BAD and, in conjunction with 14-3-3, modulates cytokine-mediated survival.

Emerging new frontiers in cardiac pacing: cardiac pacing in heart failure

Indications for pacing have leapt beyond sinus node dysfunction and atrioventricular (AV) block. Pacing for the purpose of improving hemodynamics has become the prime subject of exploration. Several studies have reported hemodynamic and clinical improvement with bi-ventricular pacing and AV sequential pacing. Data is still pouring in from the various ongoing trials regarding the beneficial effects of these methods of pacing. This is especially true in a subset of patients with intractable heart failure. There are several indicators to identify these patients. Those who have intra-ventricular conduction defects and those who demonstrate hemodynamic improvement after temporary pacing are certainly the candidates who will benefit most from this new form of pacing. Prolonged PR interval or left bundle branch block with intractable heart failure also falls into this category. The rationale of pacing in heart failure is to correct the cardiac dysynchrony that occurs frequently in these patients. Cardiac dysynchrony can occur due to ineffective synchronization between atria and ventricles (AV dysynchrony) or due to lack of synchronization within the two ventricles (ventricular dysynchrony). This is overcome by AV sequential pacing or by multi chamber pacing using the coronary sinus as portal of entry of the electrode into the cardiac vein to pace the left ventricle. Pacing leads and generators have been designed to suit the new found methods of pacing. Clinical trials are in full swing to establish the efficacy of these methods.

The C677T mutation of the methylenetetrahydrofolate reductase gene is not associated with the risk of coronary artery disease or venous thrombosis among Chinese in Taiwan

OBJECTIVES

We sought to investigate the association between the methylenetetrahydrofolate reductase (MTHFR) gene C677T mutation and the risk of coronary artery disease (CAD), myocardial infarction (MI) and venous thrombosis (VT) in a Chinese population in Taiwan.

METHODS

The subjects included 218 CAD patients, 107 VT patients, and their age- and sex-matched controls. DNA was extracted from the blood and genotypes were determined by polymerase chain reaction, restriction mapping with HinfI and gel electrophoresis.

RESULTS

The distribution of MTHFR genotypes was similar in the CAD cases and controls; the genotype TT was present in 6.0% of CAD patients, as compared to 6.9% of CAD control subjects (p = 0.165; odds ratio = 0. 86; 95% confidence interval = 0.40-1.85). The frequency of the T allele was also similar in CAD cases and controls (25.5% vs. 24.8%; p = 0.788). There was no significant association between TT homozygosity and the risk of MI. The genotype distributions and the frequency of the T allele were also similar in VT cases and controls.

CONCLUSIONS

Our data suggest that there is no association between the C677T mutation of the human MTHFR gene and the risk of CAD or VT among Chinese in Taiwan.

Low prevalence of coronary arterial disease in Chinese adults with mitral stenosis

BACKGROUND

We attempted to evaluate the prevalence of coronary artery disease in Chinese adults with severe rheumatic mitral stenosis.

METHODS

We prospectively performed coronary angiography in 119 consecutive Chinese patients older than 40 years old (mitral valve area less than 1.5 cm2) who were about to undergo balloon mitral commissurotomy for significant rheumatic mitral stenosis. The exclusion criteria were the presence of left atrial cavitary thrombi or mitral regurgitation greater than grade 3.

RESULTS

There were 32 men (26%) and 87 women (74%) with a mean age of 55 +/- 9.7 years (ranging from 40 to 78). Ninety-two patients (77%) were in atrial fibrillation. The prevalence of risk factors for atherosclerotic cardiovascular disease were hypertension (22%), diabetes mellitus (4%), hypercholesterolemia > or = 240 mg/dL (5%), hypertriglyceridemia > or = 150 mg/dL (13%), and cigarette use (7%). Coronary artery disease on angiography was defined as stenosis of more than 50% of the luminal diameter. We found that only 2 patients (1.7%) had coronary artery disease.

CONCLUSION

The prevalence of coronary artery disease was much lower than in previous reports, some of which, however, had already pointed out the relatively low prevalence of coronary artery disease in rheumatic mitral disease. The definite mechanisms require further study.

Localizing ventricular tachycardia through entrainment

Area(s) of slow conduction are thought to be present within the reentry circuit of most clinically important ventricular tachycardia (VT). To prevent recurrence after ablation of VT late after myocardial infarction, it is desirable to localize and destroy area(s) of slow conduction "critical link" within the reentry circuit. Conventionally, they may be identified by endocardial catheter mapping, continuous electrical activity, mid-diastolic potentials, earliest endocardial activation, pace-mapping etc. However, none of these methods are very specific. Entrainment method may be used to localize the slow conduction zone of reentrant VT. Concealed entrainment is consistent with pacing at a site in the reentry circuit but may also occur at some "bystander" sites that are close to the reentry circuit but are not participating in the circuit itself. During pacing at the slow conduction area of the reentry circuit, the stimulus to QRS (S-QRS) interval should equal the electrogram to QRS (EG-QRS) interval during VT. Similarly the post-pacing interval (PPI) approximates the tachycardia cycle length. During pacing at bystander sites, the S-QRS interval may be greater, less than or equal to the EG-QRS interval, depending on the conduction time from the bystander site to the circuit. The PPI, however, always exceed the tachycardia cycle length. In conjunction with concealed entrainment, the use of diastolic potential, double potentials and continuous electrical activity enhances the prediction of radiofrequency termination of post-infarction VT.

Sinoatrial nodal artery aneurysm with right ventricular outflow tract compression: report of a case

We described a 16-year-old boy with sinoatrial nodal (SAN) artery aneurysm that drained into right atrium and compressed right ventricular outflow tract. The patient was clinically asymptomatic. Hemodynamic study revealed a 15 mm Hg peak systolic pressure gradient at right ventricular outflow tract. The fistula was successfully excised without sequalae. Cathet. Cardiovasc. Intervent. 51:328-331, 2000.

Cardiovascular manifestations of pheochromocytoma

Pheochromocytomas are rare tumors that originate in chromaffin tissue and produce their distant variant effects by secretion of catecholamines, tending to mislead the emergency physicians to a wrong diagnosis. Therefore, we analyze the clinical cardiovascular manifestations in patients with pheochromocytoma to improve the diagnostic ability of the emergency physicians. All patients presenting to the Chang Gung Memorial Hospital between January 1993 and December 1997 with a final diagnosis of pheochromocytoma had their charts reviewed. The data of 25 patients including age, sex, adrenergic stimulation presentations, electrocardiographic changes, location of the tumor, and complications were analyzed. Hypertension was the most important major manifestation and fluctuation of blood pressure drew our attention to the possibility of pheochromocytoma. Six patients had abnormal electrocardiographic ST-T segment changes. Five of them had chest pain which prompted them to undergo coronary angiography before surgery, because acute coronary syndrome (unstable angina and acute myocardial infarction) was suspected initially. However, all of them turned out to have normal coronary arteries. Right-sided pheochromocytoma was found in three of these five patients. We should maintain high index of suspicion for pheochromocytoma in patients presenting with chest pain, fluctuating blood pressure, and ischemic electrocardiogram (ECG) changes despite any typical isoenzyme changes. Pheochromocytoma should also be included in the differential diagnosis of acute coronary syndrome because acute catecholamine secretion may induce chest pain and abnormal ECG changes mimicking an ischemic episode. The right-sided pheochromocytoma may present more striking electrocardiographic abnormalities and clinical manifestations.

Actinomycosis imitating nasopharyngeal carcinoma

The incidence of nasopharyngeal actinomycosis is exceedingly rare. To our knowledge, only 1 case has been reported previously. This article presents 4 cases of actinomycosis involving the nasopharynx that imitated nasopharyngeal carcinoma. Acidic gas exposure and farming of aquatic products are possibly involved in the pathogenesis of nasopharyngeal actinomycosis. Patients in the case studies completely recovered after 4 weeks of oral antibiotic treatment. We recommend including actinomycosis in the differential diagnosis of nasopharyngeal neoplasms.

The adenosine transporter of Toxoplasma gondii. Identification by insertional mutagenesis, cloning, and recombinant expression

Purine transport into the protozoan parasite Toxoplasma gondii plays an indispensable nutritional function for this pathogen. To facilitate genetic and biochemical characterization of the adenosine transporter of the parasite, T. gondii tachyzoites were transfected with an insertional mutagenesis vector, and clonal mutants were selected for resistance to the cytotoxic adenosine analog adenine arabinoside (Ara-A). Whereas some Ara-A-resistant clones exhibited disruption of the adenosine kinase (AK) locus, others displayed normal AK activity, suggesting that a second locus had been tagged by the insertional mutagenesis plasmid. These Ara-A(r) AK+ mutants displayed reduced adenosine uptake capability, implying a defect in adenosine transport. Sequences flanking the transgene integration point in one mutant were rescued from a genomic library of Ara-A(r) AK+ DNA, and Southern blot analysis revealed that all Ara-A(r) AK+ mutants were disrupted at the same locus. Probes derived from this locus, designated TgAT, were employed to isolate genomic and cDNA clones from wild-type libraries. Conceptual translation of the TgAT cDNA open reading frame predicts a 462 amino acid protein containing 11 transmembrane domains, a primary structure and membrane topology similar to members of the mammalian equilibrative nucleoside transporter family. Expression of TgAT cRNA in Xenopus laevis oocytes increased adenosine uptake capacity in a saturable manner, with an apparent K(m) value of 114 microM. Uptake was inhibited by various nucleosides, nucleoside analogs, hypoxanthine, guanine, and dipyridamole. The combination of genetic and biochemical studies demonstrates that TgAT is the sole functional adenosine transporter in T. gondii and a rational target for therapeutic intervention.

Obstructive hypertrophic cardiomyopathy in Taiwanese adults

The purpose of this study was to analyze the clinical profiles, echocardiographic findings, and mortality among adult Taiwanese patients with obstructive hypertrophic cardiomyopathy (HCM) at Chang Gung Memorial Hospital, a university-affiliated tertiary referral center in suburban Taipei. We reviewed the medical records of all adult (> 15 years of age) patients referred to our laboratory for echocardiographic examinations of cardiac diseases from May 1990 through December 1996. The diagnosis of obstructive HCM required an outflow gradient of above 10 mm Hg and the presence of asymmetric septal hypertrophy of the left ventricle. Follow-up information on was obtained from hospital records, questionnaires, interviews, or the National Death Certificate Registry. Of the 6.798 adults who underwent echocardiographic examinations during the study period 122 (1.79%) had obstructive HCM. The mean +/- standard deviation age of the patients was 62.2 +/- 12.6 years, and females predominated (n = 76, 62.3%). During the mean follow-up period of 3.2 years, the annual all-cause mortality rate was 4.7%. Most deaths were due to concurrent medical conditions. The annual cardiac mortality rate was 0.99%. Logistic regression analysis identified medication with calcium channel blockers as the only negative predictor (relative risk = 0.26, 95% confidence interval = 0.07-0.96) of all-cause mortality, and left atrial size as the only positive predictor (relative risk = 1.18, 95% confidence interval = 1.02-1.37) of cardiac mortality. Cox regression analysis confirmed the former association, but not the latter. Thus, in our institution, obstructive HCM had a low prevalence among adult patients referred for echocardiographic examination. These patients were elderly and often had other associated medical conditions. The high all-cause mortality rate was largely due to non-cardiac causes. These findings suggest that obstructive HCM tends to have a benign clinical course. Large atrial size could be an independent predictor of cardiac mortality, but this possibility requires further confirmation.

Gender differences in the presentation of adult obstructive hypertrophic cardiomyopathy with resting gradient: a study of 122 patients

The present study investigated gender differences among adult patients with obstructive hypertrophic cardiomyopathy (OHCM) and resting gradient. Using outflow gradients >10 mmHg and the presence of asymmetrical septal hypertrophy of the left ventricle as inclusion criteria, 122 patients were identified among patients referred for echocardiographic examinations between May 1990 and October 1996. Clinical, echocardiographical and follow-up data were compared between male and female patients. The female patients were significantly older than male patients (mean age +/-SD 66.7+/-10.5 vs 54.8+/-12.5 years). The female patients had a smaller interventricular septal wall thickness, less frequent systolic anterior movement of the mitral valve, more frequent association with hypertension, and less frequent association with ischemic heart disease (IHD) and giant T wave inversion. In this study population, adult female patients presented with OHCM 12 years later than males. Whether this represents female patients' reluctance to seek medical attention early, a different disease process that affects predominantly elderly females, or a gender-specific end organ response to aging, hypertension, IHD and other processes, or the protective effects of estrogen remains to be determined.

Insertional tagging of at least two loci associated with resistance to adenine arabinoside in Toxoplasma gondii, and cloning of the adenosine kinase locus

A genetic approach has been exploited to investigate adenylate salvage pathways in the protozoan parasite Toxoplasma gondii, a purine auxotroph. Using a new insertional mutagenesis vector designed to facilitate the rescue of tagged loci even when multiple plasmids integrate as a tandem array, 15 independent clonal lines resistant to the toxic nucleoside analog adenine arabinoside (AraA) were generated. Approximately two-thirds of these clones lack adenosine kinase (AK) activity. Parallel studies identified an expressed sequence tag (EST) exhibiting a small region of weak similarity to human AK, and this locus was tagged in several AK-deficient insertional mutants. Library screening yielded full-length cDNA and genomic clones. The T. gondii AK gene contains five exons spanning a approximately 3 kb locus, and the predicted coding sequence was employed to identify additional AK genes and cDNAs in the GenBank and dbEST databases. A genomic construct lacking essential coding sequence was used to create defined genetic knock-outs at the T. gondii AK locus, and AK activity was restored using a cDNA-derived minigene. Hybridization analysis of DNA from 13 AraA-resistant insertional mutants reveals three distinct classes: (i) AK-mutants tagged at the AK locus; (ii) AK- mutants not tagged at the AK locus, suggesting the possibility that another locus may be involved in regulating AK expression; and (iii) mutants with normal AK activity (potential transport mutants).

Extrasplenic pseudoaneurysm. The role of color flow Doppler ultrasound in diagnosis

Pseudoaneurysm of the splenic artery has been rarely reported and the Doppler echocardiographic finding seldom described. Herein we report a rare case of huge extrasplenic pseudoaneurysm, which was detected by color flow Doppler ultrasonography and successfully treated by ligation of the splenic artery and resection of the pseudoaneurysm.

Microbial dechlorination of 2,4,6-trichlorophenol in anaerobic sewage sludge

The dechlorination of 2,4,6-trichlorophenol (TCP) in municipal sewage sludge with a chlorophenol (CP)-adapted consortium was investigated. Results show that dechlorination rates differed according to the source of the sludge samples used in the batch experiments. No significant differences in 2,4,6-TCP dechlorination were observed following treatment with inoculum at densities ranging from 10% to 50% (V/V), but a significant delay was noted at 5% (V/V) density. Overall, results show that the higher the 2,4,6-TCP concentration, the slower the dechlorination rate. The addition of acetate, lactate, pyruvate, vitamin B12 or manganese dioxide did not results in a significant change in 2,4,6-TCP dechlorination. Data collected from a bioreactor experiment revealed that pH 7.0 and a total solid concentration of 10 g/L were optimal for dechlorination. Dechlorination rates decreased significantly at higher agitation speeds. 2,4,6-TCP dechlorination was enhanced under methanogenic conditions, but it was inhibited under denitrifying and sulfate-reducing conditions.

Localizing intrapulmonary shunt in hepatopulmonary syndrome by transesophageal echocardiography

Transesophageal echocardiography combining with peripheral injection of agitated saline solution is a useful diagnostic tool to detect the intrapulmonary shunt. We performed transesophageal contrast echocardiography in a case of hepatopulmonary syndrome with normal pulmonary angiography to define the intrapulmonary right-to-left shunt bilaterally.

Characterization of atrioventricular nodal reentry with continuous atrioventricular node conduction curve by double atrial extrastimulation

BACKGROUND

Characterization of typical atrioventricular nodal reentrant tachycardia (AVNRT) with continuous AVN conduction (A1A2/A2H2) curves by double atrial extrastimulation (A1A2A3) has never been systematically studied.

METHODS AND RESULTS

This study was composed of 33 patients with typical AVNRT and continuous AVN conduction curves (group 1) and 103 patients with AVNRT and discontinuous AVN conduction curves (group 2). Using A1A2A3 with predefined fast pathway-conducted A2, we examined the effects of slow pathway ablation on the A2A3/A3H3 curves in both groups. In group 1, anterograde AVN effective refractory period (272+/-33 versus 277+/-47 ms, P>0.05) and AVN Wenckebach block cycle length (320+/-45 versus 343+/-59 ms, P>0.05) remained unchanged after ablation. A2H2max was shorter in group 1 than group 2 (237+/-89 versus 395+/-72 ms, P<0.05) at baseline. It shortened in group 2 (395+/-72 versus 221+/-78 ms, P<0.001) but remained unchanged in group 1 (237+/-89 versus 214+/-59 ms, P>0.05) after ablation. A1A2A3 could further disclose discontinuous A2A3/A3H3 curves in 29 patients of group 1. A3H3max shortened in both groups (375+/-81 versus 238+/-82 ms, P<0.001, and 419+/-104 versus 220+/-78 ms, P<0.001, respectively) in a similar fashion. Successful ablation resulted in loss of the left portion of the A2A3/A3H3 curves in the 4 patients of group 1 with continuous A2A3/A3H3 curves.

CONCLUSIONS

Use of A1A2A3 could expose discontinuous A2A3/A3H3 curves in most patients with continuous A1A2/A2H2 curves. Significant shortening of A3H3max after ablation may be indicative of successful elimination of AVNRT.

The Gln-Arg 191 polymorphism of the human paraoxonase gene is not associated with the risk of coronary artery disease among Chinese in Taiwan

Paraoxonase (PON1) is a high density lipoprotein-associated enzyme capable of hydrolyzing lipid peroxides, and thus, might protect lipoproteins from oxidation. A common polymorphism due to an amino acid substitution (Gln-Arg) at codon 191 is considered to be a major determinant of variation in serum PON1 activity. Recent studies have suggested that the PON1-191 polymorphism is an independent risk factor for coronary atherosclerosis in patients with or without diabetes mellitus. The association of PON1-191 polymorphism genotypes and coronary artery disease (CAD) among Chinese subjects in Taiwan was examined. The genotype of 218 angiographically documented CAD patients and the same number of age- and sex-matched control subjects was determined. Genotypes AA, AB and BB were present in 25 (11%), 102 (47%) and 91 (42%) of control subjects, respectively, and in 30 (14%), 96 (44%) and 92 (42%) of CAD patients, respectively (chi2 = 0.57, P = 0.75 between groups). The frequency of the A allele was 0.36 for the control group and 0.35 for CAD patients (P = 0.94). No significant differences in the PON1-191 genotype frequencies could be found between groups when multivariate logistic regression analysis was performed, or different subgroups of age, sex or risk factors were analyzed. Among control subjects, there was also no significant difference between genotypes of the PON1-191 polymorphism and various clinical and lipid variables. In conclusion, our data suggest that there is no association between the Gln-Arg 191 polymorphism of the human PON1 gene and CAD among Chinese subjects in Taiwan.

Primary pericardial mesothelioma with cardiac tamponade and distant metastasis: case report

Although cardiac tamponade is a well-known complication of malignancy, it is uncommon as the initial manifestation. The antemortem diagnosis is difficult and distant metastasis is extremely rare. The presentations of primary pericardial mesothelioma are nonspecific. Pathologically, mesothelioma is the most common in primary tumors of the pericardium. Radical surgery can be used to treat a localized mesothelioma. However, the therapy for advanced primary pericardial mesothelioma is usually palliative because it is resistant to irradiation, and chemotherapy does not markedly improve the outcome. The prognosis is uniformly poor. The median survival from the onset of symptoms is 6 months. We present a 67-year-old woman with cardiac tamponade 4 months prior to a definitive diagnosis of primary pericardial mesothelioma. A computed tomogram confirmed multiple well-enhanced nodules in the pericardium, lungs and liver. Unfortunately, the patient died of multiple organ failure.

Transcatheter closure of atrial septal defect guided by on-line transesophageal echocardiography

Transcatheter occlusion of secundum atrial septal defect has been tried since 1976. Some investigators have incorporated on-line transesophageal echocardiography so as to better monitor the procedure. Most, however, have used endotracheal intubation and general anesthesia. The aim of this study was to evaluate the feasibility of adjunct guidance using on-line transesophageal echocardiography without intubation and general anesthesia in adolescent or adult patients undergoing transcatheter occlusion of secundum atrial septal defects. Ten consecutive cases (age 15-68 years) of secundum atrial septal defects with a pulmonary to systemic flow ratio of > 1.5 and a balloon-stretched diameter of < or = 25 mm were enrolled in the study. The Sideris' buttoned devices were used. The procedure was guided by on-line transesophageal echocardiography and fluoroscopy. Endotracheal intubation and general anesthesia were not employed. The diameters of the atrial septal defects ranged from 6 to 19 mm as determined by transesophageal echocardiography, from 7 to 20 mm as determined by atrial angiography and from 11 to 25 mm as determined by balloon sizing. The Sideris' buttoned devices were successfully deployed in all the patients. On-line transesophageal echocardiography greatly facilitated balloon sizing, device development and immediate assessment. One device unbuttoned 24 hours after the procedure and was retrieved smoothly. The remaining 9 patients were followed-up for 12 months. Two patients had no shunt, 3 had a trivial (average diameter by transesophageal echocardiography = 1-3 mm) and 4 had a small (average diameter = 4-6 mm) residual shunt at the latest follow-up. The cardiothoracic ratios decreased from 0.52 +/- 0.06 to 0.48 +/- 0.06 (p = 0.0131). There was no mortality, stroke or device fracture during the follow-up period. Thus, transcatheter occlusion of secundum atrial septal defect under adjunct guidance using on-line transesophageal echocardiography without endotracheal intubation and general anesthesia is promising for selected patients.

Surgical closure of atrial septal defect. Minimally invasive cardiac surgery or median sternotomy?

BACKGROUND

Closure of ostium secundum atrial septal defect (ASD) vis median sternotomy (MS) is a simple procedure for most cardiac surgeons. Minimally invasive cardiac surgery (MICS) has recently been applied in the management of intracardiac lesions.

METHODS

We report our experience in surgical closure of isolated ASD via MICS in 60 patients and via MS in 58 patients. There was no difference between these two groups in gender, age, body weight, ratio of systemic to pulmonary blood flow, and pulmonary arterial pressure.

RESULTS

The duration of cardiopulmonary bypass was significantly longer in the MICS group than in the MS group [27 to 126 min (42 +/- 12) and 14 to 158 min (27 +/- 11), respectively; (p < 0.001]. However, the length of incision, incidence of temporary pacemaker wire insertion rate, duration of endotracheal intubation, timing of oral intake, postoperative day drainage amount, incidence of parenteral analgesic injection, postoperative length of stay, and return to normal activity interval were significant shorter and lower in patients of the MICS group than in those of the MS group. All the patients recovered rapidly from the surgery. Follow-up was complete in all patients, with no late complications and no residual shunt.

CONCLUSION

Our results suggest that MICS is a good option for surgical closure of ASD.

Predictors of systemic embolism in patients with mitral stenosis. A prospective study

BACKGROUND

Most studies of the predictors of systemic embolism in patients with mitral stenosis have been retrospective.

OBJECTIVE

To prospectively study factors associated with systemic embolism in mitral stenosis.

DESIGN

Prospective cohort study.

SETTING

University-affiliated medical institution with 3000 beds.

PATIENTS

534 consecutive patients with a mitral valve area of 2.0 cm2 or less; 132 patients were in sinus rhythm, and 402 were in atrial fibrillation.

MEASUREMENTS

Nine clinical and 10 echocardiographic variables were assessed for prediction of systemic embolism over a mean (+/- SD) follow-up of 36.9 +/- 22.5 months. Diagnosis of systemic embolism was based on symptoms and signs (sudden onset of peripheral arterial ischemic or neurologic manifestations without prodromes) and on findings on computed tomography, angiography, and surgery.

RESULTS

For patients in sinus rhythm, age (relative risk [RR], 1.12 [95% CI, 1.04 to 1.21]), the presence of a left atrial thrombus (RR, 37.1 [CI, 2.82 to 487.8]), mitral valve area (RR, 16.9 [CI, 1.53 to 187.0]), and the presence of significant aortic regurgitation (RR, 22.4 [CI, 2.72 to 184.8]) were positively associated with embolism. For patients in atrial fibrillation, previous embolism (RR, 3.11 [CI, 1.66 to 5.85]) was positively associated with embolism; percutaneous balloon mitral commissurotomy (RR, 0.37 [CI, 0.18 to 0.79]) was a negative predictor.

CONCLUSIONS

It may be prudent to give anticoagulants not only to patients in atrial fibrillation and patients with previous systemic embolism but also to those showing a left atrial thrombus or significant aortic regurgitation on echocardiography. Early percutaneous balloon mitral commissurotomy may also help prevent systemic embolism in patients with mitral stenosis.

Gender differences in baseline variables, therapies and outcomes in Chinese patients with acute myocardial infarction

We prospectively studied the gender differences of baseline variables, therapies, and outcomes among a cohort of 369 Chinese patients with acute myocardial infarction from 1990 to 1995. There were 277 male and 92 female patients. The male gender had a younger mean (+/-SD) age (61.5+/-10.7 vs. 67.1+/-11.7 years, P<0.0001). Hypercholesterolemia (201.2+/-44.2 vs. 187.5+/-43.7 mg/dl, P=0.0111) and obesity (25.0 vs. 15.9%, P=0.0494) were more prominent in the female. Smoking was more prevalent in the male (78.3 vs. 18.5%, P<0.0001). The male group also had more frequent use of thrombolytic agents (19.1 vs. 9.8%, P=0.0377), beta-blockers (61.7 vs. 47.8%, P=0.0191) and heparin (25.3 vs. 12.0%, P=0.0075); but less use of angiotensin-converting enzyme inhibitors (6.9 vs. 15.2%, P=0.0149). The condition on admission was worse in the female group (Killip classification (1.5+/-0.9 vs. 1.9+/-1.0, P=0.0022), myocardial failure (8.7 vs. 2.9%, P=0.0178) and cardiomegaly (65.2 vs. 53.1%, P=0.0419). During a follow-up duration of 26.4+/-24.1 and 22.9+/-23.9 months respectively, the mortality rate was lower in the male (19.5 vs. 30.4%, P=0.0288). However after adjustment for the effect of age, the differences in Killip classification, myocardial failure, cardiomegaly and mortality became insignificant.

Catheterization-documented coronary artery disease in young Chinese adults

We conducted a retrospective study among 31 young (age<40 years) Chinese patients with catheterization-documented coronary artery disease. Male gender and smoking were the most important risk factors. Most of them had a single or two-vessel coronary artery disease. Standard treatment strategies could be applied. The prognosis appeared to be excellent.

Video-assisted cardiac surgery: preliminary results in Chang Gung Memorial Hospital

OBJECTIVE

To summarize the experience of utilization of video-assisted endoscopy in 91 patients operated on at Chang Gung Memorial Hospital, Taipei, China.

METHODS

From October 1995, through August 1996, 91 patients (44 male and 47 female) received video-assisted cardiac surgery (VACS). Their ages ranged from 1 year to 79.5 years (25.7 +/- 21.7). Indications for surgery were atrial septal defect (59 patients), ventricular septal defect (15), coronary artery disease (4), severe mitral regurgitation (4), severe tricuspid regurgitation (3), thrombosis of mitral mechanical prosthesis (3), left atrial tumor (2), and left ventricular thrombus with dilated cardiomyopathy (1). The VACS was performed through right or left anterior minithoracotomy and guided by video-assisted endoscopic techniques by means of projected images on the video monitor under extracorporeal circulation. The aorta was not cross-clamped and the myocardium was protected by continuous coronary perfusion with hypothermic fibrillatory arrest (rectal temperature 22.6 +/- 4.0 degrees C). Conventional instruments were used.

RESULTS

All lesions were corrected successfully. The bypass time was 27 to 335 minutes (72.8 +/- 52.7). The operative time was 1.3 to 8.5 hours (3.0 +/- 1.7). There were no operative deaths and 3 late deaths. Follow-up was complete in all survivors (6 to 16 months, mean 8.7). Most of them were found to be in NYHA functional I or II.

CONCLUSION

Our preliminary experiences demonstrate that VACS is simple and effective in surgical correction of selected cardiac lesions. Short-term results show good outcomes.

Unusual coronary artery ectasia and stenosis in a patient with systemic lupus erythematosus and acute myocardial infarction

Acute myocardial infarction is an important and sometimes fatal complication of systemic lupus erythematosus (SLE). We describe a case of acute myocardial infarction in a 23-year-old woman with SLE. Angiography revealed coronary ectasia in the left main and proximal circumflex coronary arteries, as well as a stenotic lesion in the left anterior descending artery. The possible pathophysiology is discussed.

On-line multiplane transesophageal echocardiography for balloon mitral commissurotomy

This study describes in detail the technique and results of on-line multiplane transesophageal echocardiographic guidance of balloon mitral commissurotomy in 150 consecutive patients with symptomatic mitral stenosis. The mitral valve area improved significantly and there were no in-hospital deaths, strokes, or emergency valve operations.

Minimal access surgical techniques in coronary artery bypass grafting for triple-vessel disease

BACKGROUND

Minimal access surgical techniques in coronary artery bypass grafting have been used mainly in the management of single-vessel disease.

METHODS

Fifteen patients, 11 men and 4 women with a mean age of 64.1 years (range, 35.7 to 78.0 years), underwent operation for triple-vessel disease using minimal access techniques. The procedures were performed through a limited left parasternal thoracotomy using femorofemoral extracorporeal circulation. The myocardium was protected by the antegrade infusion of cold blood cardioplegic solution while the aorta was cross-clamped.

RESULTS

Under direct vision, the left saphenous vein grafts were connected sequentially to the diagonal branch, obtuse marginal branch, and posterior descending branch, and the left internal thoracic artery graft was anastomosed to the left anterior descending artery in each patient. The mean aortic cross-clamp time was 86 +/- 17 minutes (range, 67 to 125 minutes). The mean duration of extracorporeal circulation was 112 +/- 22 minutes (range, 82 to 162 minutes). The postoperative course was uneventful in all patients. Follow-up was complete in all patients at a mean of 7.4 months (range, 6.0 to 8.5 months), and there were no late deaths or angina. Coronary angiography in 8 patients showed patent grafts.

CONCLUSIONS

Our experience demonstrates that minimal access surgical techniques in coronary artery bypass grafting are technically feasible and may be an alternative approach in the surgical revascularization of triple-vessel disease.

Transluminal coronary angioplasty and stenting in a patient with single coronary artery and acute myocardial infarction

An isolated single coronary artery is a rare congenital anomaly with an incidence of 0.03% to 0.4% and can present additional hazards such as myocardial ischemia, infarction, or sudden death in individuals with atherosclerotic changes in this artery. Herein, we report an acute anterior and inferior wall infarction in a 61-year-old male patient with the right coronary artery arising as a branch of the left coronary artery. Selected coronary angiography showed a 90% stenosis in the left anterior descending artery proximal to the origin of the right coronary artery. The patient underwent successful percutaneous transluminal coronary angioplasty and stenting without compromising the flow to the anomalous right coronary artery. There has been no previous reports of percutaneous transluminal coronary angioplasty and coronary stenting in a patient with this anomaly.

Interaction between obesity and genetic polymorphisms in the apolipoprotein CIII gene and lipoprotein lipase gene on the risk of hypertriglyceridemia in Chinese

To understand the effects of the interaction between genetic polymorphisms and obesity on the risk of hypertriglyceridemia (HTG), two polymorphisms, an SstI polymorphism on the apolipoprotein CIII gene and a HindIII polymorphism on the lipoprotein lipase gene, were analyzed in 339 Chinese subjects with (82 cases in the HTG group) or without HTG (257 cases in the control group). Our data revealed that the frequencies of obesity, the SstI minor allele (S2), and the HindIII major allele (H+) in the HTG group were significantly higher than in the control group. Subgroup analysis revealed that the association between these two polymorphisms and HTG occurred predominantly in nonobese subjects and in subjects with the less hypertriglyceridemic genotype of another polymorphism. Multivariate logistic regression analysis showed that all three risk factors (obesity, S2-containing chromosome, and H+ homozygosity) were associated with HTG, and an interaction was found between obesity and H+ homozygosity for the occurrence of HTG. The risk of HTG increased significantly with combinations of risk factors. Subjects can be divided into low or high risk groups for HTG using such combinations. These results provide evidence of interaction between obesity and the HindIII polymorphism of the lipoprotein lipase gene on the risk of HTG.

Cardiac tamponade in Taiwan

We retrospectively reviewed all of the patients who were treated for cardiac tamponade at Linkou Chang Gung Memorial Hospital between January 1991 and December 1995. There were a total of 112 patients (57 males, 55 females) with a mean age of 51 +/- 14 years (53 +/- 15, 49 +/- 13, respectively). Dyspnea was the most common complaint (85%). The mean blood pressure was 129 +/- 24/78 +/- 17 mmHg, and only 8% had a systolic blood pressure of less than 90 mmHg. Sinus tachycardia was the most frequent electrocardiographic finding (72%, 62/86). Diffuse low voltage was noted in 35% (30/86) of the patients and electrical alternans was seen in 17% (15/86). The mean volume of pericardial effusion was 610 +/- 263 ml. Sixty-five percent of the pericardial effusions were bloody, 31% were serosanguineous, 2% were purulent and 2% were chylous. Overall, 54.5% of the patients had malignant diseases. Of the 61 patients who died, 79% had malignancies. Thirty-five (57%) of these 48 patients had lung cancer. The mean survival time from emergent pericardiocentesis was 3.4 months. In conclusion, non-traumatic cardiac tamponade had a poor prognosis because most patients had malignant etiologies. There is still no definitive treatment for recurrent malignant pericardial effusion-induced cardiac tamponade. Percutaneous pericardiocentesis as clinically required may be the most appropriate treatment, since it is questionable whether such subjects should be subjected to the unnecessary pain and suffering associated with an operative procedure, considering their short mean survival time.

Cardiac perforation and tamponade induced by external cardiac massage: a case report

A 76-year-old woman suffered from sudden loss of consciousness while sitting in a chair. She was sent to a local hospital and found to be in shock. After a brief period of external cardiac massage, she was transferred to our hospital. In our emergency department she was lethargic with cool, clammy extremities. Her blood pressure dropped from 113/53 mmHg on arrival to 72/42 mmHg 2 hours later. Echocardiography showed massive pericardial effusion, fair left ventricular contractility and no abnormal segmental motion. The echocardiographic appearance suggested fibrin-like substance in the pericardial space, which was felt to indicate the presence of blood. Enhanced chest computerized tomography showed extravasation of contrast medium from the right ventricular outflow tract. At surgery, a small perforation was found at the infundibular area of the right ventricle, and a total of 500 mL of blood had accumulated in the pericardial space. She was discharged 7 days postoperatively, having made an uneventful recovery. External cardiac massage may cause cardiac disruption, and this should be considered in patients who have secondary hemodynamic instability following successful cardiopulmonary resuscitation.

Angiotensinogen and angiotensin-I converting enzyme gene polymorphisms and the risk of coronary artery disease in Chinese

The homozygous deletion allele (DD) of the angiotensin-I converting enzyme (ACE) gene and the T235 homozygote of the angiotensinogen (AGT) gene have been reported to be correlated with an increased prevalence of coronary artery disease (CAD) and myocardial infarction (MI). The importance of the DD genotype and T235 homozygote as genetic risk factors for CAD in Chinese remains uncertain. This study included 426 patients who underwent coronary angiography and 180 healthy subjects without clinical evidence of CAD. Coronary angiography identified 268 patients with CAD (CAD group) and 158 patients without CAD. The healthy subjects and patients without angiographic evidence of CAD constituted the control group. Three polymorphisms were studied: an insertion/deletion (I/D) polymorphism of the ACE gene and the T174 M and M235T polymorphisms of the AGT gene. No association was found between any of the three studied polymorphisms and the risk of CAD or MI in Chinese using univariate or multivariate analysis. In multivariate analysis, the relative risks were 1.20 (95% confidence interval = 0.91-1.61, P = 0.20) for the DD genotype, 1.05 (95% CI = 0.82-1.35, P = 0.69) for the T174 homozygote, and 1.19 (95% CI = 0.91-1.55, P = 0.20) for the T235 homozygote. Similarly, no significant difference was found in the frequencies of the DD genotype and the T174 and T235 homozygotes between the control group, the CAD group, the non-MI group, and the MI group when analyzed according to sex, age, or degree of risk. Our data suggest that neither the DD genotype of the ACE I/D polymorphism nor the T174 and T235 homozygotes of the AGT gene confer significant risk for CAD or MI in Chinese.

Thrombectomy for left ventricular protruding thrombi in a patient with dilated cardiomyopathy

Left ventricular thrombus is one source of cardiogenic embolism. The protruding, mobile type is the highest risk subgroup but is rarely encountered. Thrombectomy is one choice of therapy, and variously recommended based primarily on the experience with myocardial infarction. We report a rare case of successful left ventricular thrombectomy for two protruding, mobile thrombi in a patient with idiopathic dilated cardiomyopathy in order to prevent repeat embolization.

Rhabdomyolysis, acute renal failure and hepatopathy induced by lovastatin monotherapy

Lovastatin is a popular drug for the treatment of hypercholesterolemia. Few serious complications are associated with its use although rhabdomyolysis with renal failure has been reported when lovastatin is combined with cyclosporine or other drugs following transplantation. We report the case of a patient who developed hepatopathy and rhabdomyolysis accompanied by acute renal failure after 4 weeks of lovastatin monotherapy. The pathogenesis and treatment of these complications are also discussed.

Video-assisted coronary artery bypass grafting during hypothermic fibrillatory arrest

BACKGROUND

Hypothermic fibrillatory arrest without aortic cross-clamping is a technique for quieting the heart during coronary artery bypass grafting. This report reviews the preliminary results with this technique in 4 patients having video-assisted coronary artery bypass grafting.

METHODS

Four male patients 28.5 to 64.5 years old (mean age, 45.4 years) underwent operation for unstable angina. With video-assisted techniques, coronary artery bypass grafting was performed through a left anterior minithoracotomy with femoral-femoral cardiopulmonary bypass without cross-clamping the aorta. The myocardium was protected by continuous coronary perfusion during hypothermic fibrillatory arrest.

RESULTS

A left internal thoracic artery graft was anastomosed to the left anterior descending coronary artery in each patient. The posterior descending branch of the right coronary artery was grafted with a pedicled right gastroepiploic artery in 1 patient. The duration of cardiopulmonary bypass was 72 to 127 minutes (mean duration, 92 +/- 21 minutes). The postoperative course of each patient was uneventful. Follow-up (range, 3.9 to 5.8 months; mean follow-up, 4.9 months) was complete for all patients. There were no late deaths. Coronary angiography showed patent grafts. All patients were in New York Heart Association functional class I or II (mean class, 1.25).

CONCLUSIONS

Hypothermic fibrillatory arrest is a simple and effective method of quieting the heart, thereby providing a motionless operative field for video-assisted coronary artery bypass grafting.

Video-assisted thoracoscopic operation for interruption of patent ductus arteriosus in adults

BACKGROUND

Patent ductus arteriosus (PDA) is a frequent congenital heart disease encountered in premature neonates, infants, and children. Video-assisted endoscopic techniques have been used in PDA interruption since 1993. Almost all the experiences are in pediatric patients. Applications in adults with PDA have been limited.

METHODS

We report our experience of video-assisted thoracoscopic surgical ligation of PDA in adults. From August 1995 to January 1996, 60 patients with PDA were operated on with a video-assisted thoracoscopic technique. Twelve adults were identified with mean age of 30 years (range, 20 to 57 years). With the patient under general anesthesia and double-lumen endotracheal intubation, two 5-mm holes were made in the left lateral chest wall. Another 4-cm incision was made in the left third intercostal space for manipulation, dissection, and ligation. Conventional surgical instruments were used except an endoscopic grasper and an endoscopic tube that connected to a video camera. The surgical procedure was viewed on a video screen. Transesophageal echocardiography was used for monitoring during PDA ligation.

RESULTS

All patients had successful ligation of the PDA. There was no surgical mortality, but there was one morbidity; transient recurrent nerve injury, which recovered 3 months later. Ten patients were extubated in operative room and 2 patients were extubated 2 hours after the operation. Tube thoracostomy was performed in the first 2 cases; it was omitted thereafter. No patients needed narcotic to control chest pain. Postoperative follow-up by echocardiography showed faint ductal flow in 1 patient without any murmur. All patients were discharged within 3 days after the operation.

CONCLUSIONS

Our experience suggests that with refinement of instruments and surgical technique, video-assisted thoracoscopic surgical ligation can be safely applied not only in pediatric patients, but also in adults with PDA.

Video-assisted cardiac surgery. Preliminary experience in reoperative mitral valve surgery

OBJECTIVES

Video-assisted endoscopic techniques had been applied in the surgical correction of patent ductus arteriosus, vascular ring, or coronary artery disease. However, it has been used only recently in the correction of reoperative mitral valve lesions.

DESIGN

Video-assisted cardiac operations were performed on four patients who had received surgical interventions on their mitral valves and needed emergent reoperation.

PATIENTS

Four patients (3 men and 1 woman) received emergency surgery from September to December 1995 for thrombosis of mechanical mitral prosthesis (2 patients) and severe mitral regurgitation with previously failed mitral valve repair (2 patients). Six previous operations had been performed on these mitral valves. Patient ages ranged from 26.7 to 68.1 years (mean, 47.3 years). Preoperatively, acute pulmonary edema occurred in two patients, cerebral emboli occurred in one patient, and sepsis was found in one patient. Mechanical ventilatory support was used in two patients before operation.

INTERVENTION

The operations were performed through right anterior minithoracotomy, guided by video-assisted endoscopic techniques with femoro-femoral extracorporeal circulation. The operative procedures were thrombectomy of mitral prosthesis in two patients, mitral valve repair in one patient, and mitral valve replacement in one patient.

RESULTS

The duration of extracorporeal circulation was 166 to 320 min (222 +/- 67 min) and the operation time was 4.6 to 6.8 h (6.1 +/- 1.0 h). All patients recovered from the operations rapidly with uneventful postoperative courses except 1 patient who had sepsis preoperatively and died 2 months later.

CONCLUSION

Our experience demonstrates that video-assisted cardiac surgery is technically feasible and could be performed in reoperation of the mitral valve.

[Pulmonary embolism: clinical and laboratory features in 62 patients]

The clinical and laboratory features in 62 patients with acute pulmonary embolism were analized. There were 26 males, and 36 females with mean age of 63 +/- 11 (range 37 to 90). The clinical symptoms include: dyspnea (92%), chest pain and/or chest tightness (65%), cough (50%), wheezing (29%), leg swelling (32%), hemoptysis (24%), syncope (18%), leg pain (10%). Clinical signs include: tachypnea (respiratory rate > or = 20 per minute) (79%), tachycardia (37%), deep vein thrombosis (29%), cyanosis (8%), fever (> 38.5 degrees C) (2%). The possible predisposing factors include: immobilization (18%), surgery (5%), deep vein thrombosis, ever(5%), malignancy (5%), pulmonary embolism, ever (3%). Arterial blood gas analysis (while patients breathed room air) revealed mean PH of 7.46 +/- 0.06, mean PO2 of 64.5 +/- 12.1 mmHg, mean PCO2 of 35.3 +/- 4.6 mmHg, mean Alveolar-arterial O2 difference of 36.5 +/- 16.6 mmHg. The electrocardiographic changes include; nonspecific ST-T change (61%), sinus tachycardia (20%), S1Q2T3 pattern (15%), atrial fibrillation (16%), incomplete right bundle branch block (10%), complete right bundle branch block (8%), atrial premature contraction (7%), paroxysmal supraventricular tachycardia (2%). The chest x-ray findings include: cardiomegaly (48%), regional hypovascularity (31%), atelectasis (5%), pleural effusion (5%), wedge-shaped infiltrate (3%), elevated diaphragm (6%). Venous plethysmography was performed in 49 of 62 patients. Of these 49 patients, 28 patients revealed positive finding. Of these 28 patients with positive finding, 18 patients had clinical evidence of deep venous thrombosis. The in-hospital mortality rate was 10% (6/62).

Anticholinergic overdose induced torsade de pointes successfully treated with verapamil

An 18-year-old schizophrenic female was recently treated after overdosing on trihexyphenidyl, thioridazine and an unknown antidepressant. On presentation to a local hospital, she was cyanotic with dilatated pupils and in acute respiratory failure. She was intubated prior to transfer. While in our Emergency Department, she exhibited occasional premature ventricular contractions which later became intermittent torsade de pointes. As this was an anticholinergic overdose we infused sodium bicarbonate in an attempt to increase protein binding, hoping to decrease the concentration of toxic metabolites. We also tried to suppress the dysrhythmia by infusing magnesium. The potassium level was borderline low so a supplemental infusion was initiated. Defibrillation was attempted. To try to shorten the action potential duration by activating the K+ channel, an isuprel infusion was also attempted. All methods failed. The patient fluctuated between an irregular sinus rhythm with prolonged QT interval and pulseless torsade de pointes for almost 24 hours. At all times, she responded appropriately to pain. Finally we attempted blockade of the calcium channel using verapamil with dramatic results. Each single bolus (0.1 mg/kg) successfully converted the patient back to sinus rhythm for some 15-20 minutes before the torsade recurred. After the initiation of a continuous verapamil infusion (0.005 mg/kg/hr), the patient remained in stable sinus rhythm. Verapamil proved highly effective in this patient with an anticholinergic overdose induced dysrhythmia.

Video-assisted cardiac surgery in closure of atrial septal defect

BACKGROUND

Video-assisted endoscopy has been applied in the management of a variety of intrathoracic vascular lesions. Here we report its use in the correction of intracardiac congenital defects.

METHODS

Eight patients (3 male and 5 female) underwent operation for closure of an atrial septal defect. The patients ranged in age from 2.0 to 60.9 years (mean, 19.2 +/- 19.0 years). The patients weighed 11 to 66 kg (mean, 41.3 +/- 23.5 kg). The ratio of pulmonary blood flow to systemic blood flow ranged from 2.0 to 6.0 (mean, 3.4 +/- 1.3). The mean pulmonary artery pressure was 19.7 +/- 4.0 mm Hg (range, 13 to 24 mm Hg). The operations were performed through a right anterior minithoracotomy and guided by video-assisted endoscopic techniques under femorofemoral or femoral-right atrial extracorporeal circulation. The aorta was not cross-clamped, and the myocardium was protected by continuous coronary perfusion with hypothermic fibrillatory arrest (rectal temperature, 22.0 degrees +/- 2.0 degrees C). Transesophageal echocardiographic monitoring was maintained during the operations. The right atrium was entered after pericardiotomy. Primary closure of the defect was performed successfully in all patients. Conventional nondisposable instruments were used for dissection, grasping, suturing, and hemostasis.

RESULTS

The durations of extracorporeal circulation and operation ranged from 47 to 126 minutes (mean, 80 +/- 31 minutes) and from 2.2 to 4.5 hours (mean, 3.1 +/- 0.8), respectively. All patients recovered from the operation rapidly with an uneventful postoperative course.

CONCLUSIONS

Our experience demonstrates that video-assisted cardiac surgery is technically feasible and can be used with excellent results for the repair of congenital heart defects in general.