Comparison of different prophylactic myocardium saving measures during heart surgery. Effects on perioperative troponin-T levels.

OBJECTIVE: Different prophylactic myocardium saving strategies are often routine in open heart surgery. Even if theoretically well established, they must be critically reviewed in times of limited financial resources. EXPERIMENTAL DESIGN: Troponin-T (TnT) is a valuable tool to detect even minor myocardial damages independently from concomitant muscle injuries. We measured intra- and postoperative TnT-values and ST-wave deviations on the ECG in a control group and in patients receiving one of the following prophylactic MEASURES: hypothermia during cardiopulmonary bypass (CPB), nitroglycerine ([0.5 microgram/kg/min]) or nifedipine [0.1 microgram/kg/min] after aortic cross-clamping until end of operation, or perioperative Mg2+ per os. PATIENTS AND SETTING: The study included 65 patients of a university hospital with preoperative good heart function scheduled for elective aorto-coronary bypass operation. RESULTS: TnT values increased in all groups after CPB and peaked between end of operation and first post-operative day. TnT values above the critical border of 1.0 microgram/l in the early period after CPB were less often seen in the nitroglycerine and nifedipine group. No pronounced differences could be observed after the first postoperative day. Patients of the hypothermia group had most often TnT values above 1.0 microgram/l. Maximum TnT values of the control, the hypothermia and the Mg(2+)-group correlated with the duration of aortic-crossclamping. No correlation existed between ST-deviations and TnT-values. CONCLUSIONS: The prophylactic measures failed to reduce myocardial damage as evidenced by the course of TnT values. They can therefore not be recommended as routine strategies in patients with good left heart function. Especially hypothermia should be considered carefully.

Cytogenetic analysis of 750 spontaneous abortions with the direct-preparation method of chorionic villi and its implications for studying genetic causes of pregnancy wastage.

Altogether, 750 cases of spontaneous abortion between the fifth and 25th week of gestation were analyzed cytogenetically by the direct-preparation method using chorionic villi. The majority of cases (68%) were derived from early abortions before the 12th week of gestation. The frequency of abnormal karyotypes was 50.1%; trisomy was predominant (62.1%), followed by triploidy (12.4%), monosomy X (10.5%), tetraploidy (9.2%), and structural chromosome anomalies (4.7%). Among trisomies, chromosomes 16 (21.8%), 22 (17.9%), and 21 (10.0%) were prevalent. The frequency of chromosomally abnormal abortions increased with maternal age but only because of an increase of trisomy. Polyploidy and monosomy X, however, decreased. Mean maternal age was significantly increased for trisomies 16, 21, and 22 and was highest for trisomies 18 and 20. The results obtained are within the range of variability reported earlier from tissue culture-type studies. A consistent feature during our study is the excess of females in chromosomally normal abortions (male:female sex ratio 0.71). According to the methodology applied, maternal cell contamination and undetected 46,XX molar samples cannot have influenced the sex ratio. However, a bias introduced by social status or maternal age cannot be excluded. With the more rapid and convenient direct preparation of chorionic villi, reliable cytogenetic data on causes of spontaneous abortions can be obtained.

The predictive value of chorionic villus histology for identifying chromosomally normal and abnormal spontaneous abortions.

To evaluate the significance of placental histology, a collaborative histological and cytogenetic study on the products of 123 spontaneous abortions of 6-19 week pregnancies was performed. From each sample, 2-3 g was dissected randomly and analysed histologically with no prior knowledge of the karyotype. Chromosomes were prepared from the remaining chorionic villi after an overnight incubation in culture medium; they were analysed by Q- or G-banding. The frequency and type of chromosome anomalies detected are comparable to those seen in other studies. Altogether, 49.6% were chromosomally abnormal, trisomies predominating (49.2%), followed by polyploidy (27.9%) and monosomy X (14.5%). The histological classification failed for technical reasons in 11 cases (8.9%). To classify the remaining cases, 18 different histological criteria were considered independently by two pathologists. A definite diagnosis was not possible for 27 abortions (22.0%), and 50 were classified as being chromosomally abnormal. This proved to be correct in 36 (72.0%), but incorrect in as many as 14 (28.0%). No evidence for an abnormal karyotype was found histologically in samples from 35 abortuses. Nevertheless, 9 of them (25.7%) had an abnormal karyotype. The predictive value of chorionic villus histology seems to be inadequate, as only 62 of 112 samples were correctly classified by histology (55.4%). The value differs little from the a priori probability of an abnormal or normal karyotype in abortuses of corresponding gestational ages.