Macrolide inactivation gene cluster mphA-mrx-mphR adjacent to a class 1 integron in Aeromonas hydrophila isolated from a diarrhoeic pig in Oklahoma.

OBJECTIVES: To characterize a multidrug-resistant Aeromonas hydrophila isolate (CVM861) that possesses a high-level macrolide inactivation gene cluster (mphA-mrx-mphR), previously only reported in Escherichia coli. METHODS: PCR fragment length mapping, gene sequencing and Southern blotting were used to map the mphA-mrx-mphR gene cluster and flanking elements in CVM861. Conjugation experiments were done to determine whether the multidrug resistance genetic element was mobile. RESULTS: The mphA-mrx-mphR gene cluster mapped downstream of a class 1 integron and upstream of an aph(3') gene, and was present on a Tn21-like element. The gene order determined by sequencing was intI1-dhfrXII-orfF-aadA2-qacDeltaE-sul1-orf5Delta178-tnpA-mphR-mrx-mphA. Horizontal transmission of high-level macrolide resistance from CVM861 to E. coli 47011 was inconsistent; however, a composite plasmid possessing the mphA gene cluster was transferred at a conjugation frequency of 2.02 x 10(-5) per recipient. CONCLUSIONS: An mphA-mrx-mphR gene cluster was present downstream of the In2 integron located on a Tn21-like transposon in an A. hydrophila isolate. Whether this recombination event resulted in the truncation of the orf5 sequence is unknown. The presence of other resistance genes downstream of the mphA-mrx-mphR gene cluster suggests that multiple recombination events have occurred on this genetic element. This is the first known report of the mphA-mrx-mphR gene cluster carried by A. hydrophila and the first known isolation of this cluster in the United States.

Low pressure giant pulmonary artery aneurysms in the adult: natural history and management strategies.

OBJECTIVE: To describe aspects of the natural history and pathophysiology of giant low pressure pulmonary artery aneurysms and to propose potential surgical strategies. DESIGN: Cross sectional retrospective review. SETTING: Supraregional tertiary referral centre. PATIENTS: All adult patients referred for assessment of giant pulmonary artery aneurysm retrospectively identified from the Mayo Adult Congenital Heart Disease Clinic database. METHODS: Patient data were reviewed from hospital records, including echocardiograms, magnetic resonance images, radiographs, and histology slides. RESULTS: Four patients were identified with a median age of 52 years (range 37-64 years). Presenting symptoms were effort related dyspnoea, chest discomfort, and hoarseness in one patient. All patients had pulmonary regurgitation and clinical evidence of right ventricular enlargement in association with a pulsatile mass at the upper left sternal edge. Transthoracic echocardiography showed the giant pulmonary artery aneurysm involving the main pulmonary artery and proximal branches, and confirmed severe pulmonary regurgitation in all patients. None of the patients had intimal tearing, medial dissection, or pulmonary arterial rupture. The pulmonary valve was replaced to relieve symptoms and preserve right ventricular function. Pulmonary arterial histology showed medial degeneration of elastic fibres with accumulation of basophilic ground substance. CONCLUSIONS: Rupture or dissection of these low pressure aneurysms is rare. The timing of surgical intervention should be determined by changes in right ventricular size and function resulting from pulmonary regurgitation or pulmonary stenosis, and not the size of the aneurysm.

Ventricular septal defects in adults.

Because congenital ventricular septal defects are of different sizes and locations, their clinical presentation, natural history, and treatment vary greatly. This review discusses the different types of ventricular septal defects commonly seen in adults in the authors' experience and in published literature. Ventricular septal defects are either isolated small defects or larger defects associated with pulmonary stenosis, pulmonary hypertension, or aortic regurgitation. These associations play an important role in the pathophysiologic consequences of the defect, its long-term complications, and treatment options. Knowledge of the different clinical presentations in adulthood and the specific features pertinent to these defects will help in the assessment and the care of adult patients with one of the most common congenital cardiac malformations.

Coarctation of the aorta: outcome of pregnancy.

OBJECTIVES: The study sought to determine the outcome of pregnancy in women with coarctation of the thoracic aorta. BACKGROUND: Patients with coarctation of the thoracic aorta are expected to reach childbearing age, but data on the outcome of pregnancy in this population are limited. METHODS: The Mayo Clinic database was reviewed for women of childbearing age (> or =16 years old) with a diagnosis of aortic coarctation evaluated from 1980 to 2000. Spectrum of cardiovascular disease, surgical history, and obstetrical and neonatal outcomes were determined. RESULTS: Fifty women with coarctation had pregnancies: 30 had coarctation repair before pregnancy, 10 had repair after pregnancy, 4 had repair both before and after pregnancy, and 6 had no history of repair. The 50 women had 118 pregnancies resulting in 106 births. There were 11 miscarriages (9%), 4 premature deliveries (3%), and 1 early neonatal death; 38 deliveries (36%) were by cesarean section. Of the 109 offspring, 4 (4%) had congenital heart disease. A patient with Turner syndrome died of a Stanford type A dissection at 36 weeks of pregnancy. Nineteen women (38%) were known to have hemodynamically significant coarctation during pregnancy (gradient > or =20 mm Hg). Fifteen women (30%) had hypertension during their pregnancy, 11 of whom (73%) had hemodynamically significant coarctation during that time (8 with native and 3 with residual/recurrent coarctation). CONCLUSIONS: Major cardiovascular complications were infrequent but continue to be a source of concern for patients with coarctation who become pregnant. Systemic hypertension during pregnancy was common and related to the presence of a significant coarctation gradient.

Detection of Aeromonas hydrophila in a drinking-water distribution system: a field and pilot study.

A 16-month study was conducted on the presence of Aeromonas hydrophila in drinking water in Indiana, U.S.A. Enumeration was conducted in source water, in various sites within a water treatment plant, and in the distribution system in both bulk water and biofilm, as well as in a simulated (annular reactors) drinking-water distribution system. Presumptive Aeromonas spp. counts on source waters regularly approached 10(3)-10(4) CFU/100 mL, during summer months and granular activated carbon - filtered water counts ranged from <1 to 490 CFU/100 mL. In source water, presumptive Aeromonas levels were related to water temperature. Aeromonas hydrophila was never detected in the treatment plant effluent or distributed bulk water, showing disinfectant efficiency on suspended bacteria; however, isolates of A. hydrophila were identified in 7.7% of the biofilm samples, indicating a potential for regrowth and contamination of drinking-water distribution systems.

Posterior pericardial ascending-to-descending aortic bypass: an alternative surgical approach for complex coarctation of the aorta.

BACKGROUND: Coarctation of the aorta is commonly associated with recoarctation or additional cardiovascular disorders that require intervention. The best surgical approach in such patients is uncertain. Ascending-to-descending aortic bypass graft via the posterior pericardium (CoA bypass) allows simultaneous intracardiac repair or an alternative approach for the patient with complex coarctation. METHODS AND RESULTS: Between 1985 and 2000, 18 patients (13 males and 5 females, mean age 43+/-13 years) with coarctation of the aorta underwent CoA bypass through median sternotomy. Before operation, average New York Heart Association class was II (range I to IV), and 15 patients (83%) had systemic hypertension. One or more previous cardiovascular operations had been performed in 12 patients (67%); 10 patients had >/=1 prior coarctation repair. Two patients had prior noncoarctation cardiovascular surgery. Concomitant procedures performed in 14 patients (78%) included the following: aortic valve replacement in 9; coronary artery bypass surgery in 3; mitral valve repair in 2; and septal myectomy, mitral valve replacement, aortoplasty, subaortic stenosis resection, ventricular septal defect closure, and ascending aorta replacement in 1 patient each. All patients survived the operation and were alive with patent CoA bypass at a mean follow-up of 45 months. No graft-related complications occurred, and there were no instances of stroke or paraplegia. Systolic blood pressure fell from 159 mm Hg before surgery to 125 mm Hg after surgery. CONCLUSIONS: CoA bypass via median sternotomy can be performed with low morbidity and mortality. Although management must be individualized, extra-anatomic CoA bypass via the posterior pericardium is an excellent single-stage approach for patients with complex coarctation or recoarctation and concomitant cardiovascular disorders.

Late pulmonary valve replacement after repair of tetralogy of Fallot.

BACKGROUND: Pulmonary regurgitation appears to be well tolerated early after repair of tetralogy of Fallot; however, it may result in progressive right ventricular dilatation and dysfunction necessitating eventual valve replacement. Our objective was to review our experience with late pulmonary valve replacement after complete repair of tetralogy of Fallot. METHODS AND RESULTS: A total of 42 patients (16 female and 26 male) were operated on between July 1, 1974, and January 1, 1998. Mean age was 22 years (range 2-65 years). The mean interval between tetralogy repair and pulmonary valve replacement was 10.8 years (range 1.6 months-33 years). Mean follow-up was 7.8 +/- 6.0 years (maximum 23 years). Indications for pulmonary valve replacement included decreased exercise tolerance in 58%, right heart failure in 21%, arrhythmia in 14%, syncope in 10%, and progressive isolated right ventricular dilatation in 7%. Heterograft prostheses were used in 33 patients and homografts in 9. Five patients underwent isolated pulmonary valve replacement; concomitant procedures performed in 37 patients included tricuspid valve repair/replacement (n = 18), residual ventricular septal defect repair (n = 12), atrial septal defect closure (n = 4), pulmonary artery patch angioplasty (n = 17), and right ventricular outflow tract enlargement (n = 13). One patient died early (2%) of multiorgan failure. There were 6 late deaths, 3 of which were cardiac related. Survival was 95.1% +/- 3.4% and 76.4% +/- 8.9% at 5 and 10 years, respectively. Functional class of patients was improved significantly; preoperatively, 76% of patients were in New York Heart Association class III-IV, and after pulmonary valve replacement, 97% of surviving patients were in class I-II (P =.0001). Moderate to severe reduction in right ventricular function was noted on preoperative echocardiography in 59% and on late echocardiography in 18% (P =.03). Of the 5 patients who had supraventricular arrhythmias before pulmonary valve replacement, 1 had postoperative recurrence and the arrhythmia is controlled with antiarrhythmic therapy; the other 4 are in normal sinus rhythm at late follow-up. Eight patients subsequently underwent pulmonary valve re-replacement without early mortality at a mean interval of 9.0 +/- 4.2 years (range 3.8-16.8 years). Freedom from pulmonary valve re-replacement was 93.1% +/- 4.7% and 69.8% +/- 10.7% at 5 and 10 years, respectively. The only significant risk factor for re-replacement was young age at the time of the initial pulmonary valve replacement (P =.023). CONCLUSION: Late pulmonary valve replacement after tetralogy repair significantly improves right ventricular function, functional class, and atrial arrhythmias, and it can be performed with low mortality. Subsequent re-replacement may be necessary to maintain functional improvement.

Accessory mitral valve leaflet.

The presence of accessory mitral valve tissue in the left ventricular outflow tract (LVOT) is a rare cause of obstruction. Previous cases reported in the literature are associated either with other complex congenital abnormalities, or with other forms of LVOT obstruction. This report presents the first case of a duplication of the anterior leaflet of the mitral valve occurring as an isolated congenital anomaly. It produced mild subaortic obstruction. The report emphasizes the importance of transthoracic two-dimensional echocardiography and Doppler assessment in the recognition of congenital abnormalities of the mitral valve and subvalvular apparatus as a differential diagnosis of subaortic stenosis.

Idiopathic annular dilation: a rare cause of isolated severe tricuspid regurgitation.

The management of patients with severe tricuspid regurgitation (TR) requires the clinician to clarify the mechanism of regurgitation. Primary disorders of the tricuspid valve, either congenital or acquired, may be readily identified by echocardiography. Severe TR most often results from left-sided heart disease and secondary pulmonary hypertension. Cardiomyopathic processes may also cause right ventricular failure and functional TR. We report three patients with severe TR due to idiopathic annular dilation. The tricuspid valves were otherwise normal on surgical inspection, and the pulmonary pressures were not significantly elevated. Each patient was aged over 65 years and had chronic atrial fibrillation with preserved left ventricular systolic function. Surgical treatment was associated with marked clinical improvement. Clinicians should recognize this unusual but treatable cause of right-sided congestive heart failure.

Permanent pacing in patients with univentricular heart.

Patients with one of several varieties of malformation designated as "univentricular hearts" may be especially challenging when permanent pacing is required. Our objective was to review our experience in this subset of patients that had undergone permanent pacing and thus determine the optimal approach. A retrospective chart review was done of 32 patients with some variety of "univentricular" malformation who had required permanent pacing at our institution. Although technically challenging, permanent pacing in this group of patients can be successful through several approaches. The various approaches, as well as consideration of the differences that exist between patients undergoing septation and those undergoing a Fontan procedure are discussed. Although long-term permanent pacing is possible in this group of patients, before pacing begins, a thorough understanding of the anatomy and prior surgical procedures is necessary. Use of a combined atrial transvenous and ventricular epicardial pacing system may work well for some patients. With the development of newer and more reliable coronary sinus leads, dual chamber transvenous pacing with ventricular stimulation via the coronary sinus could become the approach of choice in some patients with "univentricular hearts."

Pregnancy among women with congenitally corrected transposition of great arteries.

OBJECTIVES: The outcome of pregnancy in congenitally corrected transposition of the great vessels was studied in 22 women. BACKGROUND: Women with congenitally corrected transposition of the great vessels often reach childbearing age. Although reports on the outcome of pregnancy in these women are available, the number of patients is small. METHODS: The medical and surgical databases at the Mayo Clinic were reviewed, and 36 women >16 years old with congenitally corrected transposition of the great vessels were identified. All of them were contacted, and 22 who had pregnancies were identified and the outcome of pregnancy was evaluated. RESULTS: Twenty-two women had 60 pregnancies resulting in 50 live births (83%). Forty-four deliveries (88%) were vaginal and 6 (12%) were by cesarean section. One delivery was premature at 29 weeks. There was one successful twin pregnancy. There were 11 unsuccessful pregnancies. One patient developed congestive heart failure late in pregnancy because of systemic atrioventricular valve regurgitation and required valve replacement in the early postpartum period. One patient had a total of 12 pregnancies, including 1 twin pregnancy and 2 unsuccessful pregnancies. She had multiple pregnancy-related complications, including toxemia, congestive heart failure, endocarditis and myocardial infarction (single coronary artery). No other serious pregnancy-related maternal complications and no pregnancy-related deaths occurred. The mean birth weight of the infants (n = 32) was 3.2 +/- 0.4 kg. None of the 50 live offspring have been diagnosed with congenital heart disease. CONCLUSIONS: Successful pregnancy can be achieved in most women with congenitally corrected transposition of the great arteries. The rate of fetal loss and maternal cardiovascular morbidity is increased. Because of the small number of births, the risk of congenital heart disease in offspring of women with congenitally corrected transposition of the great arteries is uncertain.

Piercing and tattooing in patients with congenital heart disease: patient and physician perspectives.

PURPOSE: The frequency and safety of ear piercing and tattooing were assessed in a group of children, adolescents, and adults with congenital heart disease (CHD). Also, a group of physicians who care for adolescents and adults with CHD were surveyed for opinions and experiences regarding piercing and tattooing. METHODS: An eight-question survey was mailed to 445 patients (181 adults and 264 children) from one center. A different five-question survey was mailed to 176 physician members of the International Society of Adult Congenital Cardiac Disease. RESULTS: The patient survey was completed by 152 of 445 (34%) patients (mean age +/- standard deviation 19.8 +/- 16.2 years; range 0.25-67 years). Eighty-eight of 152 (58%) patients were female. Ear piercing occurred in 65 of 152 (43%) patients (mean age 12.4 +/- 8.7 years; range 0.25-45 years). Prior to piercing, only 4 of 65 (6%) patients took antibiotics, but 15 of 65 (23%) had piercing-related infections. No patient had endocarditis. Infections occurred 1 week to 3 years after piercing. All were local skin infections. Tattoos were placed in 8 of 152 (5%) patients (median age 17.5 years; range 13-56 years). No antibiotic use or infections were reported in patients with tattoos. The physician survey was completed by 118 of 176 (67%) physicians. The majority of physicians did not approve of patients having piercing or tattooing performed. However, 60% of physicians believed that antibiotic prophylaxis is indicated for these procedures. CONCLUSIONS: Despite the opinion of many physicians, most patients do not take antibiotic prophylaxis for piercing and tattooing. Patients apparently do not suffer serious sequelae. The efficacy of standard antibiotic regimes as applied to ear piercing and tattooing requires further study, since these procedures are increasingly popular in modern society.

Noncardiac surgery in Eisenmenger syndrome.

OBJECTIVES: The purpose of this study was to evaluate the morbidity and mortality associated with noncardiac surgery (NCS) in patients (pts) with Eisenmenger syndrome. BACKGROUND: Noncardiac surgery in pts with Eisenmenger syndrome is associated with increased cardiovascular complications. METHODS: Fifty-eight pts with Eisenmenger syndrome (17M, 41F aged 18 to 69 years (mean 41 years) who had been followed for up to 41.5 years (mean 9.3 years) were retrospectively evaluated for any NCS done at > or = 17 years of age. RESULTS: Twenty-four pts had a total of 28 NCSs at an age of 17 to 55 years (mean 29 years) including 9 tubal ligations, 3 neurosurgeries, 3 cholecystectomies, 3 hysterectomies, 3 vasectomies, and 1 each spinal fusion, appendectomy, eye enucleation, hernia repair, hand surgery, tonsillectomy and therapeutic abortion. There were two deaths (7%), one following spinal fusion and the other following appendectomy at another institution. Fourteen of these NCSs were performed at our institution, including 11 under general anesthesia. The duration of anesthesia varied from 75 to 525 min (mean 165 min). All pts remained in sinus rhythm. The lowest systolic blood pressure (BP) ranged from 78 to 125 mm Hg. Of those 11 pts, 9 were extubated immediately after surgery and 2 needed dopamine. Ten patients were discharged without any complications, including 3 within 1 day of surgery. One death occurred 10 days following spinal fusion. This pt had the longest anesthesia (525 min) and an intraoperative systolic BP as low as 78 mm Hg. She also needed the largest fluid administration (6,475 cc) in addition to postoperative mechanical ventilation and dopamine. CONCLUSIONS: Adult pts with Eisenmenger syndrome are at increased risk with NCS, but with current/modern techniques, the risk of death is less than previously thought. In the vast majority of cases, NCS can be undertaken without substantial morbidity, and early extubation is achievable. However, even with relatively minor surgery, significant complications, including death, can occur. Referral to major centers with expertise in the care of pts with Eisenmenger syndrome is advisable.