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Biomedical subjects

W Konertz

Publications and source records attributed to W Konertz.

At least 55 records · Page 3Linked to original sources
PubMed1998

Stent implantation of the arterial duct in newborns with duct-dependent circulation.

AIMS: Little is known about the medium term results after stenting of the arterial duct in neonates and infants with duct-dependent cyanotic congenital heart disease. We report the results of stent implantation of the arterial duct in 21 neonates and infants. The defects for which the arterial duct was stented included pulmonary atresia with intact ventricular septum, critical pulmonary stenosis, and more complex defects with associated reduced pulmonary blood flow. METHODS AND RESULTS: Palmaz stents were used and successfully implanted in all the 21 patients. There were no major complications during the stent implantation procedure although two hospital deaths occurred 2 and 14 days after stent implantation. Cardiac catheterization was repeated electively 3 to 6 months after stent implantation. Stent stenosis due to intimal proliferation was noted in 11/13 patients who underwent recatheterization. Stenosis of the inner stent lumen ranged from 25% to 100%, mean 74%. Re-dilatation of the stent was required in five patients who were awaiting corrective surgery. In babies with pulmonary atresia or critical pulmonary stenosis, who also underwent additional balloon dilatation of the pulmonary valve, spontaneous closure of the stented arterial duct was well tolerated and when it occurred, the right ventricular size had increased and the circulation was no longer duct-dependent. In patients who required subsequent surgical corrective treatment, stenting of the duct allowed the definite corrective operation to be performed as the first surgical procedure. During the follow-up period, ranging between 2 months and 2 years, mean 8.7 months increased growth of the pulmonary arteries was seen in all the patients. No distortion of the branch pulmonary arteries was seen. CONCLUSION: In patients with cyanotic congenital heart disease stenting of the arterial duct is an effective alternative to surgical aorto-pulmonary shunts.

Abnormalities, Multiple↗
PubMed1998

Splanchnic oxygen transport and lactate metabolism during normothermic cardiopulmonary bypass in humans.

UNLABELLED: The effect of normothermic (36.2 degrees C +/- 0.6 degree C) nonpulsatile cardiopulmonary bypass (CPB) on splanchnic (hepatic) blood flow (SBF), splanchnic oxygen transport (DO2spl) and oxygen consumption (VO2spl), splanchnic lactate uptake and gastric mucosal pH (pHi, gastric tonometry) was studied in 12 adults (New York Heart Association class II, ejection fraction > or = 0.4) undergoing coronary artery surgery. SBF was estimated with the constant-infusion indocyanine green (ICG) technique using a hepatic venous catheter. DO2spl, VO2spl, and splanchnic lactate uptake were calculated using the Fick principle after the induction of anesthesia, during aortic cross-clamping, after CPB, and 2 and 7 h after admission to the intensive care unit (ICU). SBF, DO2spl, and VO2spl did not decrease during CPB but increased after ICU admission, whereas pHi decreased 7 h after ICU admission. Initial ICG extraction was 0.78, which decreased to 0.54 during aortic clamping and remained low thereafter. The increased arterial blood lactate concentrations were not associated with a decreased splanchnic lactate uptake. We conclude that normothermic CPB is not associated with deterioration in the global intestinal oxygen supply. The increase of blood lactate levels and the decrease in ICG extraction, as well as in pHi, are consistent with a systemic inflammatory response to CPB. IMPLICATIONS: This study demonstrated that normothermic cardiopulmonary bypass (at flows > 2.4 L.min-1.m-2) was not associated with deterioration in global intestinal oxygen delivery, which suggests that increased blood lactate concentrations and decreased gastric mucosal pH and indocyanine green extraction are manifestations of a systemic inflammatory response to cardiopulmonary bypass.

Adult↗
PubMed1998

Hyperprocalcitonemia in patients with noninfectious SIRS and pulmonary dysfunction associated with cardiopulmonary bypass.

BACKGROUND: The incidence of noninfectious systemic inflammatory response syndrome (SIRS) associated with coronary artery bypass surgery and the potential role of several inflammatory parameters as early markers of pulmonary dysfunction induced by cardiopulmonary bypass (CPB) were investigated. METHODS: Forty patients undergoing elective coronary artery bypass surgery were studied prospectively. Perioperative lung function was monitored using the lung injury score introduced by Murray and colleagues, by measuring venous admixture (Qs/Qt), and, in some cases, by measuring extravascular lung water. Serum concentrations of the inflammatory parameters (procalcitonin, interleukin-6, sL-selectin, leukocyte elastase, neopterin, leukocyte counts, and C-reactive protein) were determined sequentially. The American College of Chest Physicians-Society of Critical Care Medicine classification system was used to diagnose SIRS. RESULTS: According to the entry criteria, SIRS developed in 17 (42%) patients after operation. Nine patients of this group showed signs of acute pulmonary impairment, whereas patients without SIRS had no lung injury. In all patients with acute lung injury, distinct increases in procalcitonin concentrations ranging from 5.1 to 14.3 ng/ml were measured. In patients with SIRS but without acute lung injury and in patients without SIRS, none or only negligible increases in serum concentrations of procalcitonin were seen. Compared with procalcitonin, other inflammatory parameters investigated were less sensitive and less specific to indicate pulmonary dysfunction secondary to CPB. CONCLUSIONS: Procalcitonin seems to be an appropriate parameter indicating the early development of severe noninfectious SIRS and for predicting pulmonary dysfunction secondary to CPB.

Aged↗
PubMed1998

Concomitant pulmonary valve replacement, VSD closure and coronary artery bypass surgery.

BACKGROUND AND AIMS OF THE STUDY: Although pulmonary valve stenosis may be treated by percutaneous balloon valvulotomy, surgery is preferred in adult patients with dysplastic valves. METHODS: Recently a 50-year-old man with isolated, calcific pulmonary stenosis and concomitant coronary artery disease was referred for surgery. Preoperatively, he suffered from dyspnea (NYHA class I-II) and angina pectoris (CCS class I-II). During catheterization a peak-to-peak gradient of 120 mmHg was measured across the pulmonary valve, while angiography revealed two-vessel coronary artery disease. RESULTS: During surgery, after opening the main pulmonary artery, an unsuspected small ventricular septal defect (VSD) and a severely calcified, altered pulmonary valve were detected. The VSD was closed and the valve replaced with a stentless bioprosthesis; concomitant double coronary artery bypass grafting was performed. The postoperative course was uneventful. CONCLUSIONS: Adult patients with pulmonary valve stenosis and concomitant coronary artery disease can be treated simultaneously by surgery with excellent results. Replacement devices may be homografts, or as in this patient, a stentless xenograft.

Bioprosthesis↗
PubMed1998

Pediatric circulatory support.

BACKGROUND: Mechanical circulatory support in infants and small children is still a crucial issue. Until recently technological advances have been limited to the adult population. METHODS: Between February 1994 and December 1996, 553 infants or children underwent operation at our institution. Ten of them were treated with cardiac assist systems. Their ages ranged from 4 days to 8 years (median 5 months). In 8 patients we used a pulsatile circulatory support system available in 6 sizes (9, 10, 22.5, 25, 54, and 60 mL). A centrifugal pump was used in 2 additional infants. In 3 children cardiac assist was considered as a bridge to transplantation; in the remaining patients postcardiotomy failure or cardiogenic shock led to mechanical support. RESULTS: Median duration of assist was 4 days (range 8 hours to 17 days). In all cases we could observe recovery of renal, hepatic, and cardiac function in the immediate postimplantation period. Six patients survived and could be discharged either after successful transplantation or after myocardial recovery from postcardiotomy failure. The cause of death in 4 cases was bleeding and multiorgan failure. No technical failures occurred with either system. CONCLUSIONS: The pulsatile circulatory support system seems to be feasible and effective for pediatric extracorporeal support. If the anatomic situation does not permit implantation, centrifugal pumps are an alternative.

Cardiac Surgical Procedures↗
PubMed1998

Haemodynamic changes in patients undergoing high-risk PTCA under protection of transfemoral heart- lung machine support with centrifugal pumps.

Patients with a high risk for myocardial revascularization by cardiological or surgical means can be supported during high-risk PTCA with mechanical circulatory support (supp HR-PTCA). Between November 1994 and June 1997 we performed 28 supp HR-PTCA's under protection of a heart-lung machine (HLM) with femoro - femoral cannulation under regional anesthesia. We approached 2.8+/-1.5 stenoses and 1.7+/-0.6 vessels per patient. Primary success rate was 95 percent of the treated vessels. During unloading, pulmonary artery mean pressure fell to 42+/-29% of the starting value, and LVEDP was decreased to 36+/-42%. Mechanical unloading also resulted in a significant reduction of left ventricular volumes (unloaded LVEDVI and LVESVI represent 76.8% and 76.6% of pre-unloaded values, respectively, p<0.05). All patients except one survived the procedure and could be discharged from the hospital. Femoro-femoral cardio-pulmonary bypass under regional anesthesia provides sufficient protection for high risk PTCA procedures and enables high risk patients to benefit from coronary revascularization.

Adult↗
PubMed1997

Clinical experience with the MEDOS HIA-VAD system in infants and children: a preliminary report.

BACKGROUND: The need of pediatric cardiac assist is growing because of the complexity of the congenital conditions operated on and the increasing number of pediatric transplantations. We evaluated the newly developed pediatric MEDOS HIA-VAD ventricular assist device. METHODS: The pneumatic paracorporeal ventricular assist device has three left ventricular sizes (10-, 25-, and 60-mL maximum stroke volume) and three right ventricular sizes (9, 22.5, and 54 mL) and can be operated effectively with up to 180 cycles/min. We used this device in 6 consecutive pediatric patients. Intention of treatment was to bridge to transplantation in 3 patients and to aid in recovery from a cardiac operation in 3. Age ranged from 5 days to 8 years. RESULTS: Two children died during assist, 2 were weaned from the system and discharged home, and 2 had successful transplantation. During assist, laboratory variables indicative of impaired renal, hepatic, or pulmonary function normalized or showed a trend toward normalization. Both deaths were related to infection. CONCLUSIONS: With the new MEDOS HIA-VAD ventricular assist device system, pediatric mechanical cardiac assist can be performed successfully. It requires timely implantation, careful monitoring, and adequate size-matched devices.

Antibiotic Prophylaxis↗
PubMed1997

Surgical removal of atrial septal defect occlusion system-devices.

OBJECTIVE: Since 1976 a number of similar transvenous atrial septal defect occlusion systems have been developed and applied to prevent surgical intervention with extracorporeal circulation and the complications involved. One of them is the so called atrial septal defect occlusion system (ASDOS-device; Dr Ing Osypka, Germany). METHOD AND RESULTS: In our institution, eight ASDOS-devices were implanted in adults during the last year. In six individual cases, these devices were explanted because of thrombosis, residual shunts, deformations of the umbrella, disconnection of the system and atrial perforation with hemopericard. This occured 17-380 days after the implant. The surgical removal was uncomplicated in all cases. CONCLUSIONS: Because the complication rate of the ASDOS-device was unacceptably high, surgical repair was preferred.

Adult↗
PubMed1997

Stentless porcine bioprostheses for all types of aortic root pathology.

OBJECTIVE: Conventional biological and mechanical prostheses have important limitations with regard to their results concerning thrombosis, hemorrhage and long-term durability. Aortic valve replacement with stentless devices results in superior hemodynamic function because obstructing stents and sewing rims are avoided. In addition, no anticoagulation therapy is needed. METHODS: From 1 June 1991 until 31 May 1996, 235 patients received aortic valve replacement with stentless aortic porcine bioprostheses. Patients' ages ranged from 24 to 88 years (mean 64 years). In 21.3% of all patients, concomitant procedures were performed. Coronary artery bypass graft (CABG) and mitral valve surgical therapy were the most frequent ones (31 and 12 cases, respectively). Implanted valve sizes ranged from 21 to 29 mm in diameter. RESULTS: A total of 122 patients received a subcoronary implantation with the lower row performed with interrupted stitches and the upper row with a continuous suture. In 99 cases we performed the inclusion cylinder technique, also with lower interrupted sutures and running upper sutures after adaptation of the coronary ostia into the graft. In the group with small aortic roots, the total root replacement technique (n = 14) was used. Mortality at 30 days was 4.7% (11/235). Echocardiography at discharge postoperatively revealed a mean gradient across the prosthesis of 6 mm Hg. Color Doppler suggested no or trivial regurgitation in 93% of all examined patients and mild regurgitation without clinical symptoms in 7%. Up to now, 98.2% of all discharged patients have been free of valve-related reoperation. CONCLUSIONS: With implantation of stentless bioprostheses, an improved hemodynamic function will be obtained. Almost every aortic root pathology can be safely treated with any of the techniques described. The short and intermediate results seem to be at least equal to any other prostheses or treatment methods. The long-term performance of these devices is still under investigation.

Animals↗
PubMed1997

Orthotopic heart transplantation in a child with heterotaxia syndrome: a case report.

We report a case of a successful orthotopic heart transplantation in a seven year old boy with heterotaxia syndrome, d-transposition of the great arteries, rudimentary right ventricle, double inlet left ventricle, valvular pulmonary stenosis, left-sided peripheral pulmonary artery stenosis, deficient atrial septation, and left-sided superior and inferior vena cava. In this case of congenital heart defects, three specific surgical procedures were necessary to make heart transplantation feasible. A synthetic patch was interposed in the single atrium to create two separate atria. To handle the mismatch of the donor's and recipient's aortic diameters, the donor's aortic diameter was enlarged by including the aortic arch into the anastomosis. The left-sided superior vena cava was led to the right appendage by interposing a piece of autogenous aorta.

Anastomosis, Surgical↗
PubMed1997

Medos/HIA-assist system: first experiences with mechanical circulatory assist in infants and children.

The Medos/HIA-System is a new pneumatically driven system for mechanical circulatory assist. The system is characterized by excellent efficiency at high heart rates and is available with three ventricles of 10, 25 and 60ml stroke volume. It can be used as left-, right- or biventricular assist device. Our preliminary experiences with this novel system for support of infants and children are reported.

Blood Pressure↗
PubMed1996

Preoperative two- and three-dimensional transesophageal echocardiographic assessment of heart tumors.

BACKGROUND: Two-dimensional transesophageal echocardiography is the most widely used diagnostic approach in the rare entity of heart tumors. The aim of this study was to assess the diagnostic usefulness of three-dimensional echocardiography in comparison with the two-dimensional technique in a rare clinical setting. METHODS: Twenty-seven patients (18 women; mean age, 49.7 +/- 14 years) with a histologically proven diagnosis of a cardiac tumor were studied. The primary diagnosis was done by a two-dimensional transthoracic echocardiography (n = 9) and transesophageal echocardiography (n = 18). In addition, we performed three-dimensional transesophageal assessment in 5 patients with left atrial myxomas. The echocardiographic findings were compared with the intraoperative appearance and pathologic diagnosis. RESULTS: The echocardiographically suspected diagnosis of a heart tumor in 29 cases was histologically correct in 27 patients (myxomas, 20; epicardial lipoma, 1; malignant epicardial mesothelioma, 1; metastatic processes of hypernephromas, 2; and undifferentiated tumors of the pericardium, 3). Only the combination of multiplane transesophageal and three-dimensional echocardiography was able to demonstrate the shape, dimensions, location, origin, surface, three-dimensional movement, and involvement of valves and was most useful in the preoperative diagnosis and planning. CONCLUSIONS: Three-dimensional transesophageal echocardiography yields important additional clinical information and improves the operative planning. Three-dimensional echocardiography may become the best approach to study the anatomy and pathology of the heart as it provides an objective display of cardiac size and shape in heart tumors.

Adult↗
PubMed1996

Biological bridging after repair of an anomalous origin of a left coronary artery.

We report on an unusual case of surgical repair for anomalous origin of the coronary artery from the pulmonary artery, in a young patient who underwent tunnel repair with concomitant heterotopic heart transplantation to support severely impaired left ventricular function. Four years later, the graft was removed after confirmation of ventricular arrest and excellent recovery of the patient's own heart.

Coronary Vessel Anomalies↗