Biomedical subjects
Markus K Heinemann
Publications and source records attributed to Markus K Heinemann.
Images in vascular medicine. Morphologic and functional assessment of extensive pulmonary arteriovenous malformations using MRI.
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Time-resolved contrast-enhanced MR angiography of the thorax in adults with congenital heart disease.
OBJECTIVE: The aim of this study was to evaluate the diagnostic value of time-resolved contrast-enhanced MR angiography in adults with congenital heart disease. SUBJECTS AND METHODS: Twenty patients with congenital heart disease (mean age, 38 +/- 14 years; range, 16-73 years) underwent contrast-enhanced turbo fast low-angle shot MR angiography. Thirty consecutive coronal 3D slabs with a frame rate of 1-second duration were acquired. The mask defined as the first data set was subtracted from subsequent images. Image quality was evaluated using a 5-point scale (from 1, not assessable, to 5, excellent image quality). Twelve diagnostic parameters yielded 1 point each in case of correct diagnosis (binary analysis into normal or abnormal) and were summarized into three categories: anatomy of the main thoracic vessels (maximum, 5 points), sequential cardiac anatomy (maximum, 5 points), and shunt detection (maximum, 2 points). The results were compared with a combined clinical reference comprising medical or surgical reports and other imaging studies. Diagnostic accuracies were calculated for each of the parameters as well as for the three categories. RESULTS: The mean image quality was 3.7 +/- 1.0. Using a binary approach, 220 (92%) of the 240 single diagnostic parameters could be analyzed. The percentage of maximum diagnostic points, the sensitivity, the specificity, and the positive and the negative predictive values were all 100% for the anatomy of the main thoracic vessels; 97%, 87%, 100%, 100%, and 96% for sequential cardiac anatomy; and 93%, 93%, 92%, 88%, and 96% for shunt detection. CONCLUSION: Time-resolved contrast-enhanced MR angiography provides, in one breath-hold, anatomic and qualitative functional information in adult patients with congenital heart disease. The high diagnostic accuracy allows the investigator to tailor subsequent specific MR sequences within the same session.
Late results after PTCA for coronary stenosis after the arterial switch procedure for transposition of the great arteries.
BACKGROUND: The arterial switch operation has become the surgical approach of choice for d-transposition of the great arteries, but there is an increased awareness of adverse sequelae in some survivors. Long-term patency and normal function of the translocated coronary arteries must be achieved. It is reported that dependent of the prior coronary status, 3% to 11% of all survivors have proximal coronary stenosis or complete occlusion develop after arterial switch operations. However, treatment of these stenoses is still a matter of debate. Late results after percutaneous transluminal coronary angioplasty (PTCA) for coronary stenosis after the arterial switch operation for d-transposition of the great arteries are reported. METHODS: Seven children after arterial switch operation for d-transposition of the great arteries who had subsequently undergone PTCA for coronary stenosis were angiographically re-evaluated 3 to 15 months after the initial PTCA and again after 3 to 5 years. RESULTS: All children survived the initial PTCA procedure. There were no late deaths. The degree of stenosis before PTCA ranged from 74% to 97%; immediately after PTCA from 5% to 10%; at 3 to 15 months after PTCA from zero to 6%; and at 3 to 5 years after PTCA from zero to 3%. Three to 5 years after PTCA all children showed normal development of the treated coronary artery. CONCLUSIONS: Primary PTCA of stenotic proximal coronary arteries after the arterial switch procedure for d-transposition of the great arteries seems to be an effective treatment with excellent long-term results.
DDD pacemaker implantation after Fontan-type operations.
Bradyarrhythmias developing after Fontan-type operations impair the function of the univentricular heart causing fatigue, headaches, ascites, and protein-losing enteropathy (PLE). Transvenous inaccessibility, requiring epicardial implantation, accounts for the reluctance to implant a pacemaker (PM). Between 1997 and 2000, 24 patients (mean age 9.5 years, range 6 months to 19 years) with Fontan-type operations received DDD pacing systems with atrial steroid-eluting stitch-on electrodes (mean capture threshold 1.9 V/0.5 ms, range 0.4-3.5 V) and ventricular screw-in electrodes (mean capture threshold 1.7 V/0.5 ms, range 0.1-3 V). The systems were implanted at the time of conversion from atrio- to cavopulmonary connections in 5 patients, at the time of a total cavopulmonary Fontan operation in 6, and 1-50 months thereafter (mean = 18) in 13 patients. A right ventricular anatomy was present in 13 (54%) of 24 of PM recipients, versus 35% of the overall population. After a mean follow-up of 3.5 years, the PM were functioning in DDD mode in 23 of the 24 patients. Length of hospital stay in the ten patients who underwent repeat sternotomy was 5 days, without procedure related complications. In three children a repeat sternotomy was avoided by implanting the atrial electrodes during the Fontan operation. All patients improved clinically, including resolution of PLE in four patients. Bradyarrhythmias may lead to significant morbidity after Fontan-type operations. Electrophysiological evaluation is advised at follow-up. The indication for implantation of a DDD pacemaker system should be liberal. Placing atrial electrodes during the Fontan operation, especially in the presence of a right ventricular anatomy, avoids repeat sternotomy.