Supramitral ring: an unusual cause of congenital mitral stenosis. Case series and review.

Supramitral ring, also known as membranous supravalvular mitral stenosis is a rare cause of congenital mitral stenosis, with less than 100 cases appearing in the literature since its first description in 1902. We present a small series encountered at the university medical center during the last five years. The natural history of the condition is reviewed along with diagnostic tools, aspects of surgical repair, and anesthetic technique that facilitates early extubation and ICU discharge.

Sildenafil (viagra) facilitates weaning of inhaled nitric oxide following placement of a biventricular-assist device.

Sildenafil is a selective phosphodiesterase type 5 inhibitor used in the treatment of erectile dysfunction. We report the use of sildenafil to blunt the rebound pulmonary hypertension seen following withdrawal of inhaled nitric oxide (NO) and milrinone. The relatively long duration of sildenafil's action on pulmonary artery pressures and lack of systemic hemodynamic effect make it an attractive option to facilitate weaning of inhaled NO.

Origin of the left pulmonary artery from the aorta: embryologic considerations.

We observed a case of anomalous origin of the left pulmonary artery from the aorta in which the media of the abnormal vessel and the main pulmonary artery were fused, but without communication. This is the fifth isolated case of repair without the use of cardiopulmonary bypass reported in the literature. This pathology should be included in the aortic arch anomalies as a partial or complete failure of development of the left sixth arch.

Tissue inhibitor of metalloproteinase-4 instigates apoptosis in transformed cardiac fibroblasts.

Tumor cells become malignant, in part, because of their activation of matrix metalloproteinases (MMPs) and inactivation of tissue inhibitor of metalloproteinases (TIMPs). Myocardial tumors are rarely malignant. This raises the possibility that the MMPs and TIMPs are differentially regulated in the heart compared to other tissues. Therefore, we hypothesized that a tissue specific tumor suppressor exists in the heart. To test this hypothesis we prepared cardiac tissue extracts from normal (n = 4), ischemic cardiomypathic (ICM) [n = 5], and dilated cardiomyopathic (DCM) [n = 8] human heart end-stage explants. The level of cardiospecific TIMP-4 was determined by SDS-PAGE and Western-blot analysis. The results suggested reduced levels of TIMP-4 in ICM and DCM as compared to normal heart. TIMP-4 was purified by reverse phase HPLC and gelatin-sepharose affinity chromatography. Collagenase inhibitory activity of chromatographic peaks was determined using fluorescein-conjugated collagen as substrate and fluorescence spectroscopy. The activity of TIMP-4 (27 kDa) was characterized by reverse zymography. The role of TIMP-4 in cardiac fibroblast cell migration was examined using Boyden chamber analysis. The results suggested that TIMP-4 inhibited cardiac fibroblast cells migration and collagen gel invasion. To test whether TIMP-4 induces apoptosis, we cultured cardiac normal and polyomavirus transformed fibroblast cells in the presence and absence of TIMP-4. The number of cells were measured and DNA laddering was determined. The results suggested that TIMP-4 controlled normal cardiac fibroblast transformation and induced apoptosis in transformed cells. Cardiospecific TIMP-4 plays a significant role in regulating the normal cell phenotype. The reduced levels of TIMP-4 elicit cellular transformation and may lead to adverse extracellular matrix degradation (remodeling), cardiac hypertrophy and failure. This study suggests a possible protective role of TIMP-4 in other organs which are susceptible to malignancy.

Falsely elevated bispectral index during deep hypothermic circulatory arrest.

A 2-month-old infant underwent repair of a ventricular septal defect under deep hypothermic circulatory arrest. Bispectral index and EEG suppression ratio were evaluated using an Aspect BIS monitor. Erroneous readings from the monitor could have led to a potentially dangerous alteration in surgical and anaesthetic management.

Preoperative exposure to calcium channel blockers suggests increased blood product use following cardiac surgery.

PURPOSE: In this study the authors reviewed the medical records of a random sample of patients undergoing coronary artery bypass grafting (CABG) during the preceding ten years at University Medical Center. The purpose of this study was to evaluate the impact of exposure to calcium channel blockers (CCB's) on blood product use following cardiopulmonary bypass (CPB). DESIGN: Retrospective medical record review. SETTING: University hospital. PARTICIPANTS: 527 patients undergoing CABG or re-do CABG. INTERVENTIONS: The medical records of approximately 50% of patients undergoing CABG or re-do CABG at University Medical Center between 1988 and 1998 were randomly selected by the medical records librarian for review. Preoperative medications, bypass time and temperature, and blood product use were recorded. RESULTS: Of the 527 patients studied, 309 (59%) had no exposure to CCB's. 218 (41%) were on CCB's at the time of admission. Patients who were on CCB's had an average 12.5 (+/- 1.0) blood product units transfused following bypass whereas those not on CCB's had an average 8.7 (+/- 0.6) units transfused (p < 0.001). Use of packed red blood cells (p < 0.001), fresh frozen plasma (p = 0.018) and platelets (p = 0.023) were each individually significantly increased. CONCLUSIONS: In this study, it appeared that patients exposed to CCB's before cardiac revascularization received significantly more blood products than those who were not exposed to CCB's. Because of the limitations imposed by retrospective studies, further prospective studies are warranted to define the clinical significance of CCB use in the perioperative period.

Isolated cardiac metastasis of cervical carcinoma presenting as disseminated intravascular coagulopathy. A case report.

BACKGROUND: An isolated cardiac metastasis from cervical carcinoma is very rare. This report describes the unusual presentation in a patient diagnosed and successfully treated for stage IB squamous cell carcinoma of the cervix, presenting six months later with disease metastatic to the heart. CASE: A 44-year-old woman presented with hand swelling and bruising. She had undergone successful surgical treatment of a stage IB squamous cell cervical carcinoma six months previously. Computed tomography revealed a large mass in the right ventricle, confirmed by echocardiography. The patient underwent surgery, where the mass was biopsied and debulked under a cardiopulmonary bypass. Frozen section confirmed metastatic squamous cell carcinoma. The patient was discharged with follow-up radiation and chemotherapy. CONCLUSION: All women with myocardial abnormalities and a history of squamous cell carcinoma of the cervix should be suspected of developing a myocardial metastasis until proven otherwise.

Selective use of chest tubes in thoracotomies for congenital cardiovascular procedures.

BACKGROUND: Advantages and complications have been reported from the use of chest tubes (CT). To reduce the incidence of complications we have employed a selective use of CT in thoracotomy for congenital cardiovascular procedure; ie, in absence of air leaks and fluid to be drained, no CT was inserted. METHODS: The lung was reexpanded and air evacuated during the chest closure. Early and 6 hours chest roentgenograms were performed on every patient. This study retrospectively reviews the results of this selective approach in 546 patients operated on between 1980 and 1998 mainly for patent ductus arteriosum ligation, pulmonary artery band, aortic coarctation, Blalock-Taussig shunt. Four hundred and eighteen patients did not receive a CT at the initial surgery (group I), and 128 patients received a CT either before or at surgery (group II). RESULTS: 40 patients in group I developed an air or fluid collection large enough to require a CT. Only one patient had complication, from an undetected hemothorax. Nine patients in group II required another CT, and one patient developed a pneumothorax upon pulling out the CT. No death in either group was related to the use or lack of use of the CT. A total of 378 CTs and collecting chambers were saved. CONCLUSIONS: A selective approach to the use of CT in thoracotomies for cardiovascular procedures can be employed with minimal complications, more comfort for the patient, and cost savings.

Discrete membranous subaortic stenosis: improved results after resection and myectomy.

BACKGROUND: Despite an adequate resection, a significant recurrence rate is encountered in patients undergoing operation for discrete membranous subaortic stenosis. The fibrous membrane and hypertrophied myocardium commonly are removed, but because of the involved risks, the resection may be inadequate and contribute to the recurrence rate. METHODS: A review of the cases of 23 patients undergoing operation for discrete membranous subaortic stenosis from 1980 to 1994 was undertaken. Fourteen patients (61%) had coexisting cardiac lesions, all of which were concomitantly repaired. RESULTS: The left ventricle-aorta gradient decreased from a preoperative mean of 63.39 +/- 7.63 mm Hg to 15.17 +/- 3.06 mm Hg postoperatively (p < .001) during a mean follow-up of 3.32 +/- 0.58 years. Aortic insufficiency decreased postoperatively in 8 patients (34.8%), remained unchanged in 6 patients (26.1%), and showed only insignificant progression in 4 patients (17.4%). There were no early deaths, and the single late death was not cardiac related. No patient had development of endocarditis or heart block or required a pacemaker. One patient (4.3%) had a recurrence, which required reoperation. CONCLUSIONS: Our results suggest that aggressive myectomy in concert with membrane resection constitutes safe treatment for discrete membranous subaortic stenosis and is associated with low rates of endocarditis, recurrence, and progression of aortic insufficiency.

The effect of scavenging on nitrous oxide pollution in the delivery suite.

United States standards recommend limits to occupational exposure to nitrous oxide. This can be achieved by the scavenging of waste anaesthetic gases, a routine practice in the operating suite, but less common in the delivery suite. In this study, nitrous oxide levels in the delivery room were measured, and scavenged and unscavenged levels were compared. Unacceptable levels of nitrous oxide were found in unscavenged delivery rooms, and in the majority of cases, scavenging reduced nitrous oxide pollution to within recommended limits.

End-tidal oxygen measurement compared with patient factor assessment for determining preoxygenation time.

Time to adequate preoxygenation was assessed in 200 elective surgical patients, using measurement of end-tidal oxygen concentration. A variety of patient factors were assessed as to their ability to predict the time required to preoxygenate a patient. Of the 200 patients, 23 (11.5%) were unable to be adequately preoxygenated; most of these cases were due to a poor mask fit. The average time for preoxygenation was 154 seconds (range 43-364 seconds). Of those patients who could be preoxygenated, 46 (23%) required more than three minutes. Although a regression equation could be constructed to calculate time required for preoxygenation, the wide standard errors of the coefficients preclude a clinically useful predictive equation. We thus found that we could not accurately predict time required for preoxygenation and that a routine three minutes preoxygenation may not be sufficient for many patients. However, the measurement of end-tidal oxygen concentration is a very useful method of determining the end-point for preoxygenation.

A staged expanding pulmonary artery band.

Pulmonary artery banding is indicated in numerous congenital cardiac defects not amenable to a total repair. One complication of pulmonary artery banding, especially in neonates who require early banding, is progressive cyanosis during the rapid growth phase requiring earlier than anticipated total correction, which may produce a less than optimal result. A simple pulmonary artery band that enlarges as the patient grows would avoid this early complication. We report a technique of pulmonary artery banding in an animal model using different absorbable sutures. The band enlarges in a prescribed staged fashion without any further intervention, hopefully allowing growth of neonates and infants with complex congenital heart disease.

Primary pulmonary hemangiopericytoma in a 3-year-old child.

Hemangiopericytoma is an uncommon and potentially malignant mesenchymal tumor that apparently arises from spindle-shaped pericytes. The tumor usually grows insidiously until considerable size has been reached, at which point symptoms may indicate invasion of the chest wall, mediastinum, or pleura. Because of its malignant potential, hemangiopericytoma must be distinguished from other vascular tumors. While this tumor has been reported in adolescents and adults, it has never before, to our knowledge, been reported in a small child. We present, within the context of a brief review, a case of apparently benign primary pulmonary hemangiopericytoma in a 3-year-old child. Postoperatively, our patient showed no evidence of disease at 9-month follow-up evaluation. However, long-term follow-up is needed in cases of hemangiopericytoma because recurrence over several decades has been shown.

Mitral valve replacement: techniques to eliminate myocardial rupture and prevent valvular disruption.

Twenty fresh canine hearts were used to compare the peak left ventricular pressures required to disrupt prosthetic mitral valves sutured in place with horizontal mattress sutures using either subannular or supraannular placed pledgets. Separate groups were developed to determine the effect of leaving the whole mitral valve apparatus or only the posterior leaflet apparatus intact and what effect, if any, each had on the ventricular pressure required to disrupt the implanted prosthetic mitral valve. Group 1 consisted of 10 hearts with the entire mitral apparatus left in place (5 valves implanted with supraannular pledgets and 5 with subannular pledgets). Group 2 consisted of 10 hearts with only the posterior leaflet apparatus left in place (5 valves implanted with supraannular pledgets and 5 with subannular pledgets). A 29-mm Medtronic mitral valve was secured in the mitral position with a fixed number of ten pledgeted sutures in each annulus. The aorta was cannulated and normal saline solution infused into the left ventricle until end-point rupture occurred. The peak pressure and mechanism of any disruption were then noted. No specimen exhibited subannular myocardial rupture or left atrial wall dissection. Similar protection was provided by leaving the posterior leaflet only or the entire mitral valve. In each case peak left ventricular pressure resulted in only paravalvular leaking around the limited number of sutures as the end point. In each of these four groups the peak left ventricular pressures required for end-point rupture were not significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)