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Biomedical subjects

I Knez

Publications and source records attributed to I Knez.

10 recordsLinked to original sources

Aortic valve replacement with the Cryolife-O'Brien stentless aortic bioprosthesis: five-year experience.

AIM: Improved hemodynamics with stentless bioprosthesis compared to stented valves have been well documented. It has been suggested that a simplified implant model, the Cryolife-O'Brien, offers less satisfactory outcomes compared with standard stentless models. This study was conducted to prospectively evaluate the midterm results after aortic valve replacement with the Cryolife-O'Brien stentless bioprosthesis. METHODS: In 1996, the prospective clinical trial using different stentless valves was initiated in our center. From September 1996 through August 2001, 132 consecutive patients with a mean age of 72.5 years underwent aortic valve replacement with the Cryolife-O'Brien porcine stentless bioprosthesis by the same surgeon. The predominant aortic valve lesion was stenosis in 110 cases and insufficiency in 22 cases. Patients have been followed-up from 2 to 60 months, mean 28 months. Echocardiography was performed by the same echocardiographer preoperatively, intraoperatively, postoperatively at discharge, 2 to 6 months later and annually thereafter. RESULTS: Sixty-five percent of patients received a valve 25 mm in diameter or larger, 42% had concomitant coronary bypass grafting. The 30-day operative mortality rate was 6.8 %. Nine late deaths, none related to the valve, have occurred. Severe aortic insufficiency caused by oversizing led to early reoperation in 3 patients. The peak and mean systolic gradients decreased significantly during the first 12 months after implantation (p<0.001) and the effective valve areas increased significantly during this time interval (p<0.001). Eleven patients have aortic insufficiency, trivial in 7 and mild in 4. The actuarial survival at 5 years was 86+/-3%. The rate for freedom from endocarditis was 100% and for freedom from thromboembolic events 92%. CONCLUSIONS: The Cryolife-OBrien stentless bioprosthesis has superior hemodynamics and a low rate of valve-related complications thus representing a very good alternative to conventional stented bioprosthesis. The midterm results are encouraging but further follow-up is needed to determine the valve's durability.

Aged↗

Intracellular adhesion molecule-1 in patients developing pulmonary insufficiency after cardiopulmonary bypass.

OBJECTIVES: Cardiopulmonary bypass activates adhesion molecules, which are associated with systemic inflammation and organ dysfunction. The intracellular adhesion molecule-1 (ICAM-1) has been evaluated in patients presenting pulmonary dysfunction after cardiac surgery. MATERIALS AND METHODS: Postoperative serum levels of the ICAM-1 were measured in 40 patients who underwent isolated coronary artery bypass grafting, in 28 with uneventful postoperative recovery (70 %) (Group 1), and in 12 (30 %) with postoperative respiratory insufficiency (Group 2), defined by the need for prolonged (> 24 hours) mechanical ventilation using a fractional oxygen concentration of > 40 %. RESULTS: Patients in group 1 were ventilated for 12.21 +/- 4.86 hours and those in group 2 for 92.91 +/- 48.14 hours (p < 0.001). ICAM-1 decreased from 145.98 +/- 73.40 ng/ml to 81.15 +/- 114.82 ng/ml in group 1, while in group 2 ICAM-1 showed a significant higher level and increased to 435.01 +/- 130.02 ng/ml (p < 0.001). The leukocyte count increased in both groups as well as the C-reactive protein (CRP) during the postoperative course. The CRP behaves similar in both groups (p = 0.636) in contrast to the leukocyte count which was significantly higher in group 2 (p < 0.01). While none of the patients in group 1 died the mortality in group 2 was 50 % (p < 0.001). CONCLUSION: Respiratory insufficiency after cardiopulmonary bypass is associated with a distinct increase in the ICAM-1. The reason for the increase of the ICAM-1 in this small subset of patients has not been clarified.

Aged↗

Left ventricular architecture after valve replacement due to critical aortic stenosis: an approach to dis-/qualify the myth of valve prosthesis-patient mismatch?

OBJECTIVES: Left ventricular hypertrophy in patients with critical aortic stenosis (AS) is an adaptive process that compensates for high intracavitary pressure and reduces systolic wall stress followed by an increase in myocardial masses. In the present prospective clinical trial, we investigated long-term compensatory changes in left ventricular geometry and function after aortic valve replacement using mechanical bileaflet prostheses with the main emphasis on the small-sized aortic annulus and valve prosthesis-patient mismatch. METHODS: A total of 58 patients with critical AS were assigned to the following groups according to the predictive value of prosthetic valve area index (VAI): group EXMIS: 29 patients (VAI < or =0.99), expected mismatch; group NOMIS: 29 patients (VAI < or =0.99), no mismatch. At controls T(0) (before operation/operation (OP), T(1) and T(2) (4 and 20 months after OP) the left ventricular geometry was recorded by means of Imatron electron beam tomography and the transprosthetic velocities were measured by echocardiography. RESULTS: Statistical analysis showed a consistent reduction in the absolute (P=0.04) and indexed (P=0.04) left ventricular myocardial mass for both cohorts; furthermore, there was a significant difference between EXMIS and NOMIS patients concerning the factors, time and mass reduction (P=0.005), because of distinct baselines. A logistic regression report revealed preoperative cardiac output, absolute left ventricular myocardial mass, perfusion, body surface area and the native valve orifice area as predicting coefficients and factors for a minimum mass reduction of 25%. We explain a mathematical formula that turned out to be the most sensitive for correctly classified factors. CONCLUSIONS: The left ventricular geometry and transprosthetic velocities resulted in the same postoperative recovery for both EXMIS and NOMIS patients. The presented data showed that valve prosthesis-patient mismatch had no influence in several stepwise logistic regression models. We conclude that modern mechanical bileaflet prostheses allow both acceptable hemodynamics and recovery of left ventricular hypertrophy, even in small aortic annuli.

Aged↗

The circumplex structure of affect: a Swedish version.

The taxonomy of a circumplex model has been widely applied in the emotion domain and especially by researchers advocating a systematic arrangement of conscious emotional experience (see Fabrigar, Visser & Browne, 1997; Feldman Barett & Russell, 1999 for recent reviews). To rule out some of the lexical problems in the naming of affective states in the circumplex space, Larsen and Diener (1992) suggested a labeling system with forty-eight English adjectives representing eight affective states. The objective of the present study was to examine how well Swedish adjectives map onto a dimensional model of this kind, in doing so, to compose a Swedish measure for self-reported affect. The forty-eight Swedish adjectives translated from Larsen and Diener (1992) failed to capture a pure circumplex structure. However, when approximately two thirds of these adjectives were reanalyzed, a reasonable consistency with the circumplex model was reached. This suggested a composite Swedish measure for self-rated affect, with up to four adjectives representing each of the eight affective states in the circumplex space.

Adolescent↗

[Lead stability in long-term follow-up of bipolar leads].

From 1990 to 1999, 2,853 ventricular and 1,084 atrial bipolar leads of various manufacturers (Medtronic, Biotronik, Vitatron, Ela, Pacesetter and Stöckert) were implanted during first implantations of pacemakers at the University of Graz, Dept. of Cardiac Surgery. Surgical complications with the need of reintervention were analyzed during a follow up period of up to 10 years. The overall lead-related complication rate for ventricular bipolar leads was 6.5% (187 of 2,853) and 5.3% (58 of 1,084) for atrial bipolar leads. Early complications within the first month were higher in the atrium (5.3% versus 2.2% in the ventricle), primarily due to dislocation, late complications were higher in the ventricle (4.3% versus 2% in the atrium) due to insulation problems and lead fracture. Insulation material had a marked influence with a higher failure rate in some leads with polyurethane insulation compared with silicone. Therefore we recommend a close follow-up of bipolar polyurethane leads by measurement of chronic impedance in order to assess insulation problems as early as possible.

Austria↗

Minimally invasive versus conventional aortic valve operations: a prospective study in 120 patients.

BACKGROUND: Risk evaluation comparing the minimally invasive and standard aortic valve operations has not been studied. METHODS: Four surgeons were randomly assigned to perform the minimally invasive (L-shaped sternotomy) (group 1) or the conventional (group 2) operation in 120 patients exclusively. RESULTS: In both groups (n = 60) a CarboMedics prothesis was implanted in 90% of patients. There was no significant difference in the cross-clamping period (group 1, 60 minutes; range, 35 to 116 minutes), in the duration of extracorporal circulation (group 1, 84 minutes; range, 51 to 179 minutes) or in the time from skin-to-skin (group 1, 195 minutes; range, 145 to 466 minutes). Patients in group 1 were extubated earlier (p<0.001), the postoperative blood loss was less (p<0.001), and the need for analgesics was reduced (p<0.05). In 5 patients in group 1 a redo operation was required for bleeding (p>0.05), 3 patients in group 1 required a redo operation because of paravalvular leakage or endocarditis (p>0.05), the 30-day mortality rate was 1.6%. Overall the survival rate was 95% in group 1 and 97% in group 2 (mean follow-up, 294 days; range, 30 to 745 days). CONCLUSION: The advantages of minimally invasive aortic valve operation include reduced trauma from incision and duration of ventilation, decreased blood loss and postoperative pain, the avoidance of groin cannulation, and a cosmetically attractive result. Simple equipment is used with a high degree of effectiveness and with no sacrifice of safety. Our study demonstrated the practicability and reliability of this new method.

Adult↗

The influence of different strategies on clinical outcome in patients undergoing total cavopulmonary connection.

BACKGROUND: We report on results of a prospective clinical trial designed to demonstrate the influence of various strategies in "Total Cavopulmonary Connection" (TCPC) for palliative therapy of patients with "single ventricle" physiology. METHODS: From 1989 to 1997, a total of 47 patients (mean age 4.8 +/- 3.6 years) underwent definitive TCPC at our unit. 31 patients (66%) underwent one-stage TCPC, in 16 patients (34%) we performed a two-stage modified Fontan operation; 21 patients had central fenestration (4 mm). Inhalative NO therapy in the immediate postoperative period was adopted in 1993. RESULTS: Overall 5-year survival was 76.4%, after two-stage TCPC 87.5%, and 81.3% in patients undergoing fenestrated procedures. Two of three patients survived perioperative Fontan take-down. We lost 11 patients (nine early and two late deaths): three patients died primarily because of neurologic dysfunction and eight patients because of cardiac failures. Under perioperative NO therapy there was no early death. After a mean follow-up of 35.9 +/- 23.3 months, 76% of all patients were in NYHA I and 21 % in NYHA I-II. 89.7% had sinus rhythm. 42% of our patients suffered from temporary pleuropericardial effusions. CONCLUSIONS: Definitive palliation with TCPC achieves acceptable clinical results. Two-stage repair, fenestration, and postoperative inhalative NO therapy - each have a positive influence on early and long-term survival.

Administration, Inhalation↗

Invasive ductal carcinoma of the male breast expanding from pacemaker pocket decubitus.

After twenty-five years of therapy with different unifocal pacemaking systems, an 84-year old male patient developed a nonseptic pacemaker decubitus. A rare incidental finding of invasive ductal carcinoma of the right mammary gland was surgically treated by a generous excision of the tumor and by consecutive modified radical mastectomy. According to published literature, the association of invasive ductal carcinoma arising from a pacemaker pocket decubitus and followed by curative treatment has not been previously reported. We do conclude that pacemaker generators in close relationship to the mammary gland should be considered with suspicion.

Aged↗

Concomitant procedures in the small versus standard aortic root.

BACKGROUND AND AIMS OF THE STUDY: Aortic valve replacement (AVR) in the small aortic root (SAR) has always been a severe challenge with an uncertain surgical outcome. The purpose of this study was to assess the surgical and clinical performance of 19 mm and 21 mm CarboMedics valves (CPHV) based on a review of valve-related morbidity and mortality over a period of six years. METHODS: A total of 361 patients undergoing aortic valve replacement (AVR) with the CPHV between January 1989 and August 1995 was subdivided and studied. (i) Group A patients (n = 137) received 19 mm or 21 mm prostheses; subgroup AI (n = 85) underwent isolated AVR and subgroup AII (n = 52) underwent AVR with associated cardiac procedures. (ii) Group B patients (n = 224) were given 23 mm or larger prostheses; subgroup BI (n = 147) underwent isolated AVR and subgroup BII (n = 77) underwent AVR with concomitant cardiac procedures. RESULTS: Hospital mortality was group A 7.3% versus group B 4.9%. Cumulative survival after six years was 83.7% in AI and 76.9% in AII versus 72.1% in BI and 77.4% in BII. There were no significant statistical differences between the subgroups concerning cardiac mortality. Thromboembolic events occurred with a linearized rate of 1.41%/pty in group A versus 1.03%/pty in group B, the incidence of anticoagulant-related major hemorrhage was 1.41%/pty in group A versus 1.20%/pty in group B and that of periprosthetic leakage 1.69%/pty in group A versus 1.89%/pty in group B. CONCLUSION: Our results demonstrate that this bileaflet prosthesis is highly efficient in patients with small aortic roots undergoing AVR with or without associated procedures.

Adolescent↗