Superiority of magnesium cardioplegia in neonatal myocardial protection

Background. We have shown that magnesium can offset the detrimental effects of normocalcemic cardioplegia in hypoxic neonatal hearts. It is not known, however, whether magnesium offers any additional benefit when used in conjunction with hypocalcemic cardioplegia.

Methods. Twenty neonatal piglets underwent 60 minutes of ventilator hypoxia (FiO₂ 8% to 10%) followed by 20 minutes of normothermic ischemia on cardiopulmonary bypass (hypoxic-ischemic stress). They then underwent 70 minutes of multidose blood cardioplegic arrest. Five (Group 1), received a hypocalcemic (Ca⁺² 0.2 to 0.4 mM/L) cardiologic solution without magnesium, whereas in 10, magnesium was added at either a low dose (5 to 6 mEq/L, Group 2) or high dose (10 to 12 mEq/L, Group 3). In the last 5 (Group 4), magnesium (10 to 12 mEq/L) was added to a normocalcemic cardioplegic solution. Function was assessed using pressure volume loops and expressed as percentage of control.

Results. Compared to hypocalcemia cardioplegic solution without magnesium (Group 1), both high- and low-dose magnesium enrichment (Groups 2 and 3) improved myocardial protection resulting in complete return of systolic (40% vs 101% vs 102%) (p < 0.001 vs Groups 2 and 3) and global myocardial function (39% vs 102% vs 101%) (p < 0.001 vs Groups 2 and 3), and reduced diastolic stiffness (267% vs 158% vs 154%) (p < 0.001 vs Groups 2 and 3). Conversely, even high-dose magnesium supplementation could not offset the detrimental effects of normocalcemic cardioplegia resulting in depressed systolic (End Systolic Elastance [EES] 41% ± 1%) (p < 0.001 vs Groups 2 and 3) and global myocardial function (40% ± 1%) (p < 0.001 vs Groups 2 and 3), and a marked rise in diastolic stiffness (258% ± 5%) (p < 0.001 vs Groups 2 and 3). Hypocalcemic magnesium cardioplegia has now been used successfully in 247 adult and pediatric patients.

Conclusions. Magnesium enrichment of hypocalcemic cardioplegic solutions improves myocardial protection resulting in complete functional preservation. However, magnesium cannot prevent the detrimental effects of normocalcemic cardioplegia when the heart is severely stressed. This study, therefore, strongly supports using both a hypocalcemic cardioplegic solution and magnesium supplementation as their benefits are additive.     

Surgical resection and radiation therapy of desmoid tumours of the extremities: results of a supra-regional tumour centre

Purpose

Desmoid tumours of the extremity have a high recurrence rate. The purpose of this study was to analyse the outcome after resection of these tumours with special emphasis on recurrent disease and adjuvant therapeutic strategies.

Methods

In this retrospective study we evaluated prognostic factors for recurrence-free survival after surgical treatment of desmoid tumours of the extremity in 27 patients with an average age of 41 years treated from 1997 to 2009. Adjuvant radiotherapy (50–60 Gy) was given in five cases with primary and in nine patients with recurrent disease. The average follow-up was 64 months.

Results

The five-year recurrence-free survival in patients with primary disease was 33 %. Patients with negative resection margins tended to have a better outcome than patients with positive resection margins, but the difference between both groups was not significant (56 vs 14 %, p = 0.145). In patients with positive margins, adjuvant radiotherapy did not significantly improve recurrence-free survival (40 vs 14 %, p = 0.523). Patients with local recurrence had a five-year further recurrence-free survival of 47 %. In those patients further recurrence-free survival was significantly better after adjuvant radiation (89 vs 25 %, p = 0.015). Two thirds of all patients suffered moderate or severe complications due to the treatment regimen.

Conclusions

Compared to desmoids of the trunk or the head and neck region, desmoids affecting the limbs show by far the worst outcome in terms of relapse or treatment-related morbidity. The importance of negative resection margins is still not clear. Particularly in recurrent desmoids adjuvant radiotherapy appears to reduce the further recurrence rate. Therefore, a general use of radiation should be considered for this high-risk group.     

Sports activities after medial unicompartmental knee arthroplasty Oxford III—What can we expect?

Purpose

Excellent long-term results have been reported for implantation of unicompartmental knee arthroplasty (UKA). In many patients the desire for improvement in function often includes an aspiration to return to sports. The purpose of our study was to evaluate physical activities after medial Oxford-III (Biomet) UKA surgery.

Methods

Patients’ physical activity before and after the surgery was assessed using a self reporting questionnaire. We used the Oxford knee scoring system (OKS), the WOMAC-, the Knee society- (KSS) and the UCLA-score to assess postoperative knee function. The mean follow-up was 4.2 years. The female-to-male ratio was 1.3:1. The mean age at surgery was 65.3 years.

Results

Of the 131 patients studied 78 participated in some kind of sports before surgery (mean age 64.4 years), while 53 patients did not perform any sports (mean age 66.5 years) (p > 0.05). At follow-up the patients in the active group were significantly younger than the patients in the inactive group (p < 0.05). The majority of patients (80.1 %) returned to their level of sports activity after UKA surgery. Six patients took up sports after surgery while 15 patients stopped their sports. Among the active patients we found a shift from high- towards low-impact sports. The active patients had significantly higher scores for the OKS, KSS, WOMAC and UCLA score. The complication rate was comparable in both groups.

Conclusion

Our study demonstrates that a high degree of patient satisfaction in terms of sports activity can be achieved using the Oxford-III UKA for medial osteoarthritis.     

Noninvasive grading of untreated gliomas: a comparative study of MR imaging and 3-(iodine 123)-L-alpha-methyltyrosine SPECT

PURPOSE: To compare the accuracy of magnetic resonance (MR) imaging scores with that of 3-(iodine 123)-L-alpha-methyltyrosine ((123)I-IMT) single photon emission computed tomography (SPECT) in the noninvasive grading of untreated gliomas. MATERIALS AND METHODS: The study comprised 15 patients with low-grade gliomas (grades I-II, according to World Health Organization criteria) and 33 patients with high-grade gliomas (grades III-IV). The lesions were evaluated by using an MR imaging score based on nine criteria. The (123)I-IMT uptake was quantified as the ratio between the amino acid uptake in the tumor and that in the contralateral hemisphere. To test for potentially significant differences in diagnostic performance between contrast material-enhanced MR imaging and (123)I-IMT SPECT, binormal receiver operating characteristic curves were fitted to the data and compared by using the area test. RESULTS: The accuracy of MR imaging in the noninvasive grading of untreated gliomas was higher than that of (123)I-IMT SPECT (88% vs 79%). However, the difference in diagnostic performance was not significant on the basis of findings at receiver operating characteristic analysis (P >.2). Neither MR imaging nor (123)I-IMT SPECT allowed differentiation between high-grade gliomas (grades III and IV). CONCLUSION: Although (123)I-IMT uptake is significantly higher in high-grade gliomas than in low-grade gliomas, the performance of (123)I-IMT SPECT adds little to the accuracy of determining tumor grade when MR imaging is performed.     

"Soap-Bubble" visualization and quantitative analysis of 3D coronary magnetic resonance angiograms.

In order to compare coronary magnetic resonance angiography (MRA) data obtained with different scanning methodologies, adequate visualization and presentation of the coronary MRA data need to be ensured. Furthermore, an objective quantitative comparison between images acquired with different scanning methods is desirable. To address this need, a software tool ("Soap-Bubble") that facilitates visualization and quantitative comparison of 3D volume targeted coronary MRA data was developed. In the present implementation, the user interactively specifies a curved subvolume (enclosed in the 3D coronary MRA data set) that closely encompasses the coronary arterial segments. With a 3D Delaunay triangulation and a parallel projection, this enables the simultaneous display of multiple coronary segments in one 2D representation. For objective quantitative analysis, frequently explored quantitative parameters such as signal-to-noise ratio (SNR); contrast-to-noise ratio (CNR); and vessel length, sharpness, and diameter can be assessed. The present tool supports visualization and objective, quantitative comparisons of coronary MRA data obtained with different scanning methods. The first results obtained in healthy adults and in patients with coronary artery disease are presented.     

Isotopic renal function studies in severe hypothyroidism and after thyroid hormone replacement therapy

AIM: To investigate the possible changes in the renal tubular function in severe short-term hypothyroidism using (99m)Tc-MAG(3) renography. METHODS: 27 consecutive thyroidectomized patients (7 males and 20 females) aged 19-79 (mean 53) years were included in the present study. (99m)Tc-MAG(3) renography was performed in all patients before and after thyroid hormone replacement therapy. In addition, (51)Cr-EDTA clearance and serum creatinine concentrations were determined. RESULTS: The serum creatinine concentrations were significantly increased in hypothyroidism as compared with the concentrations after thyroxine substitution (1.30 +/- 0.44 vs. 1.04 +/- 0.32 mg/dl, p < 0.05). According to the (51)Cr-EDTA clearance, the glomerular filtration rate was significantly lower in hypothyroidism than after treatment (61 +/- 18 vs. 75 +/- 23 ml/min). In contrast, we did not find any significant change in the renographic parameters for (99m)Tc-MAG(3) before and after treatment (total excreted activity 20 min after administration 51 +/- 12 vs. 54 +/- 14%; T(max) left:right 4.2 +/- 1.77 : 3.91 +/- 1.06 min vs. 4.1 +/- 1.66 : 4.4 +/- 1.96 min). CONCLUSIONS: We did not find any influence of thyroid hormones on the outcome of (99m )Tc-MAG(3) renography. As (99m)Tc-MAG(3) reflects the tubular function, it seems that the renal hemodynamic changes in severe hypothyroidism mainly affect the glomerular function. In general, the glomerular filtration rate reduction seems to be reversible after hormone substitution therapy; however, care has to be taken in patients with renal insufficiency.