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Biomedical subjects

T R Karl

Publications and source records attributed to T R Karl.

At least 19 recordsLinked to original sources
PubMed2001

Epicardial atrial pacemaker lead placement after multiple cardiac operations.

We describe a simple technique for the implantation of left atrial epicardial pacing leads in children with congenital heart disease who have undergone multiple operations. The pulmonary veins are exposed to reveal the pulmonary venous to atrial confluence using a left thoracotomy. A pacemaker lead is secured to the posterior left atrium inferior to the lower pulmonary vein. This approach provides a reliable site for atrial lead placement without the need for extensive dissection.

Child↗
PubMed2001

Neonatal cardiac surgery. Anatomic, physiologic, and technical considerations.

Neonatal repair for all cardiac lesions is an attractive but as yet unattainable goal for the surgical team. We are obliged to consider both lesions that must be repaired in the absolute neonatal period, and those for which later repair is an option. This article serves as an update on some issues relating to neonatal heart surgery. The first section deals with selected general aspects of perioperative support. The second section discusses two representative lesions that illustrate many of the problems encountered in neonatal cardiac surgery: transposition of the great arteries and hypoplastic left heart syndrome.

Age Distribution↗
PubMed2001

Recurrent arch obstruction after repair of isolated coarctation of the aorta in neonates and young infants: is low weight a risk factor?

BACKGROUND: Repair of aortic coarctation is often delayed in small infants because of the belief that such patients are at risk of recurrent arch obstruction and that growth will decrease this risk. To determine whether low weight was a risk factor for recurrent arch obstruction, we reviewed our experience with coarctation repair via left thoracotomy in infants less than 3 months of age. METHODS: From 1990 to 1999, 103 patients less than 3 months of age underwent repair of aortic coarctation through a left thoracotomy. Median age was 18 days (1-90 days), with 45 patients less than 2 weeks. Median weight was 3.3 kg (1.0-6.4 kg) and 14 patients were less than 2 kg. The method of repair was resection and end-to-end anastomosis in 64 patients, subclavian flap angioplasty in 34, and patch augmentation of the arch in 5. Demographic, echocardiographic, and operative variables were analyzed for correlation with recurrent arch obstruction. RESULTS: One early and 1 late death occurred, both in patients who had complications but no evidence of recoarctation. At median follow-up of 24 months, reinterventions for recurrent arch obstruction were performed in 15 patients. The median time to reintervention was 5 months and was less than 1 year in 12 patients. Kaplan-Meier freedom from arch reintervention was 88% at 1 year (95% confidence intervals: 82%-94%) and 82% at 5 years (95% confidence intervals: 72%-92%). Factors associated with shorter duration to arch reintervention by univariable Cox regression included younger age (continuous, P =.01; <2 weeks, P =.005), smaller transverse arch (absolute diameter, P <.001; indexed to weight, P =.03; indexed to ascending aortic diameter, P =.02), and smaller ascending aorta (absolute diameter, P =.02). Smaller absolute transverse arch diameter and younger age were the only independent predictors of shorter time to arch reintervention by multivariable Cox regression analysis. Weight and type of repair did not correlate with risk of recoarctation. CONCLUSIONS: Low weight is not a risk factor for recurrent obstruction after repair of coarctation of the aorta in infants less than 3 months of age. Rather, risk of recoarctation is more a function of the anatomy of the arch. Thus, it is not indicated to delay repair in low weight infants with the goal of achieving growth.

Aortic Arch Syndromes↗
PubMed2001

The bidirectional cavopulmonary shunt for hypoplastic left heart syndrome.

The use of the bidirectional cavopulmonary shunt has had a favorable effect on the outcome of surgery for hypoplastic left heart syndrome. In this chapter, the physiology, indications, and technical aspects are discussed, along with comments regarding postoperative management and outcome.

Heart Bypass, Right↗
PubMed2000

Climate extremes: observations, modeling, and impacts.

One of the major concerns with a potential change in climate is that an increase in extreme events will occur. Results of observational studies suggest that in many areas that have been analyzed, changes in total precipitation are amplified at the tails, and changes in some temperature extremes have been observed. Model output has been analyzed that shows changes in extreme events for future climates, such as increases in extreme high temperatures, decreases in extreme low temperatures, and increases in intense precipitation events. In addition, the societal infrastructure is becoming more sensitive to weather and climate extremes, which would be exacerbated by climate change. In wild plants and animals, climate-induced extinctions, distributional and phenological changes, and species' range shifts are being documented at an increasing rate. Several apparently gradual biological changes are linked to responses to extreme weather and climate events.

Animals↗
PubMed2000

Congenital Heart Surgery Nomenclature and Database Project: corrected (discordant) transposition of the great arteries (and related malformations).

The extant nomenclature for congenitally corrected transposition of the great arteries is reviewed for the purpose of establishing a unified reporting system. The subject was debated and reviewed by members of the STS-Congenital Heart Surgery Database Committee and representatives from the European Association for Cardiothoracic Surgery. All efforts were made to include all relevant nomenclature categories using synonyms where appropriate. Congenitally corrected transposition of the great arteries is a complex cardiac lesion that is associated with ventricular septal defect, left ventricular outflow tract obstruction, and tricuspid valve abnormalities. Nomenclature for this lesion has been variable and confusing. Herein we attempt to clarify the terminology, with an emphasis on identification of synonymous and nonsynonymous appellations. A comprehensive database set is presented that is based on a hierarchical scheme. Data are entered at various levels of complexity and detail that can be determined by the clinician. These data can lay the foundation for comprehensive risk stratification analyses. A minimum database set is also presented that will allow for data sharing and would lend itself to basic interpretation of trends. Outcome tables relating diagnoses, procedures, and various risk factors are presented.

Databases, Factual↗
PubMed2000

Veno-venous bypass to prevent myocardial ischemia during right heart bypass operation in PA, IVS, and RV dependent coronary circulation.

There is a risk of myocardial ischemia in patients with pulmonary atresia and intact ventricular septum associated with right ventricle dependent coronary circulation, especially during open heart operation. Cardiopulmonary bypass unloads the right ventricle, and thereby reduces the coronary perfusion pressure in an area that is wholly or partly dependent on the right ventricle. We present a veno-venous bypass technique to keep the right ventricle beating and ejecting to supply the oxygenated blood into the right ventricle dependent myocardium and consequently to prevent myocardial ischemia during right heart bypass operation.

Anastomosis, Surgical↗
PubMed1999

Damus-Kaye-Stansel connections in children with previously transected pulmonary arteries.

BACKGROUND: In patients with a univentricular arteriovenous connection, transection of the main pulmonary artery may be performed as part of a bidirectional cavopulmonary shunt or Fontan procedure. The proximal stump of the pulmonary artery may remain in the systemic circulation. In cases with a discordant ventriculoarterial connection, subsequent restriction of the bulboventricular foramen may lead to subaortic stenosis. The subaortic stenosis can be corrected in some patients by directing the systemic flow through a combined nonobstructed aortopulmonary outlet, as in the Damus-Kaye-Stansel connection. Previous closure of the pulmonary artery has been considered by some investigators to be a relative contraindication to the Damus-Kaye-Stansel procedure, unless an allograft root can be added to the circuit after excision of the closed pulmonary stump. METHODS: Three patients with previously transected pulmonary arteries underwent a modified Damus-Kaye-Stansel connection using the native pulmonary valve and the proximal pulmonary artery stump. RESULTS: The native pulmonary valves have functioned well despite thrombus formation in the proximal stump in 2 patients before Damus conversion. All 3 patients are alive and well after 108, 19, and 3 months, with competent nonobstructed ventriculoarterial connections. CONCLUSIONS: If transection and closure of the pulmonary artery as part of a previous palliation has spared the pulmonary valve, then the native pulmonary outlet might be used for a safe Damus-Kaye-Stansel connection.

Child↗
PubMed1999

Incipient left ventricular rupture complicating anomalous left coronary artery.

A 4-month-old girl presented with 2 weeks of symptoms and physical signs of heart failure. Echocardiography demonstrated marked left ventricular dilation, thinning of the myocardium with anterolateral akinesis, mitral regurgitation, a moderate pericardial collection, and an anomalous left coronary artery from the pulmonary artery. At operation there was a tense hemopericardium and a site of imminent rupture through a transmural anterior infarction. The anomalous artery was reimplanted in the ascending aorta, and an extensive infarct resection and ventricular repair performed. Support with a left ventricular assist device was required for 3 days, but the infant subsequently made a satisfactory recovery. Left ventricular rupture is a very rare complication of this lesion, but should be considered if there is evidence of a pericardial collection.

Coronary Vessel Anomalies↗
PubMed1999

Does left ventricular outflow tract obstruction influence outcome of interrupted aortic arch repair?

BACKGROUND: In previous studies left ventricular outflow tract obstruction (LVOTO) has been recognized as an important factor affecting survival and reoperation probability in patients having repair of an interrupted aortic arch (IAA). METHODS: All 72 patients who underwent operation for IAA from January 1, 1985 to June 30, 1997 were reviewed. The presence or absence of LVOTO was noted and the immediate and long-term results were analyzed. RESULTS: Type A IAA was found in 23 patients and type B IAA in 49 patients. Anomalous right subclavian artery was noted in 15 patients, all of whom had type B IAA. LVOTO was identified in 36 patients before arch repair and was associated with the presence of type B IAA and anomalous right subclavian artery (p = 0.02 and 0.007, respectively). There were 2 hospital deaths (within 30 days) for a mortality of 2.8% (confidence limit [CL] = 0% to 6.6%). There were 7 late deaths over 3,737 patient-months of follow-up (9.7%, CL = 2.9% to 16.6%). Actuarial survival for the whole cohort was 84.8% (CL = 73.2% to 94.4%) at 12 years. There was 87% 10-year survival (CL = 60% to 93%) for patients with LVOTO at presentation compared with 83% (CL = 62% to 92%) for patients without LVOTO (p = 0.85, hazard function 0.87). Twenty-eight patients have required at least one reoperation. The use of conduits to restore right ventricular to pulmonary artery continuity predicted the need for reoperation (p = 0.0001). Patients with presence of a nonseptatable heart were also more likely to need reoperation (p = 0.027) when compared to the rest of the cohort. Freedom from reoperation was 47.3% (CL = 30% to 62%) at 12 years. In patients with LVOTO, freedom from reoperation (55% at 10 years, CL = 33% to 72%) was not significantly different from those patients without LVOTO at presentation (29% at 10 years, CL = 7% to 56%; p = 0.97, hazard function 0.7). Actuarial freedom from recurrent arch obstruction requiring reintervention was 82.7% (CL = 66.7% to 98.7%) at 12 years. CONCLUSIONS: Neonatal complete repair of patients with IAA is possible with low mortality. LVOTO was not a significant risk factor for hospital or late death in patients having complete repair of IAA during this period. The use of conduits for right ventricular to pulmonary artery continuity and the presence of a nonseptatable heart are important risk factors for further operation and will continue to provide added morbidity to these patients.

Aorta, Thoracic↗
PubMed1999

IL-6 and IL-8 levels after cardiopulmonary bypass are not affected by surface coating.

UNLABELLED: BACKGROUND.:Contact of blood with the surfaces of the cardiopulmonary bypass (CPB) circuit has been implicated as a cause of the inflammatory response. We undertook a prospective randomized trial of 200 pediatric patients, all with a calculated total bypass flow of less than 2.3 L/min (< 0.96 L/m2/min). METHODS: Patients were randomly assigned to 1 of 4 CPB groups: (1) Nonheparin-bonded circuit with no albumin preprime; (2) Nonheparin-bonded circuit with albumin preprime; (3) Heparin-bonded circuit with no albumin preprime; (4) Heparin-bonded circuit with albumin preprime. Measurements of cytokines, (interleukin [IL]-6, IL-8) and blood cell counts were made prebypass and 6 and 24 hours after institution of cardiopulmonary bypass. RESULTS: Analysis of variance showed no significant difference in any of the clinical or biochemical characteristics of the 4 groups. The interaction between heparin-bonded oxygenators and albumin preprime was not significant. No important differences in IL-6 or IL-8 concentrations were noted after CPB using either heparin or nonheparin-bonded oxygenators with albumin or albumin free preprime using two-way analysis of variance. CONCLUSIONS: Albumin preprime and heparin-bonding do not attenuate the inflammatory response component attributable to the concentration of these markers.

Albumins↗
PubMed1999

Excellent long-term functional outcome after an operation for anomalous left coronary artery from the pulmonary artery.

OBJECTIVE: The aim of this study was to review the results of operations for anomalous left coronary artery from the pulmonary artery and the late outcome for exercise capacity, left ventricular function, and mitral regurgitation. METHODS: Twenty-one patients underwent operations over an 18-year period (median age, 9 months; range, 6 weeks-26 years) with a median follow-up of 6.5 years (range, 2 months-18 years). In addition to clinical and echocardiographic follow-up, patients at our institution were also investigated with radionuclide scans (n = 10) and treadmill exercise testing (n = 8). RESULTS: There were no operative or late deaths (0%; 95% confidence interval [CI], 0% and 16%). Five patients required support with a left ventricular assist device. Eighteen patients are currently in New York Heart Association class I, and 3 patients are mildly symptomatic. On nuclear gated scan at a mean of 6 years after the operation, the left ventricular ejection fraction was 64% (SD, 3%) at rest and increased to 74% (SD = 3%) on exercise (95% CI for the difference, 6%, 14%; P =.001). Treadmill endurance was normal for age (9.8-14.5 minutes) in those old enough to exercise. On echocardiography (n = 18), the current fractional shortening was 34% (SD, 4%) in the 15 patients with normal or only mildly abnormal ventricular septal motion. Three patients have undergone mitral valve operations. The left ventricular end-diastolic dimension fell from 48 mm (SD, 5.8 mm) before surgery to 35.1 mm (SD, 5.2 mm) at 1 year after the operation, and the fractional shortening increased over the first year from 19.6% (SD, 9.3%) to 32.8% (SD, 5.9%; both P <.001). CONCLUSIONS: Long-term clinical outcome and left ventricular function are good, despite severe left ventricular dysfunction at presentation.

Adolescent↗
PubMed1999

Advances in pediatric cardiac surgery.

During the past year there have been many important scientific and clinical publications addressing important aspects of pediatric cardiac surgery. Herein we review some of the more significant contributions, with our own commentary added. Space limitations prevent a more comprehensive review.

Cardiac Surgical Procedures↗