Pregnancy in Patients with Prosthetic Heart Valve / 대한흉부외과학회지

BACKGROUND: This is a retrospective study of 42 pregnancies from 33 women with prosthetic heart valves who were on anticoagulation regimen prior to or during their pregnancy. MATERIAL AND METHOD: Of the 17 women with bioprosthesis, 15 had 21 pregnancies following cessation of the anticoagulation therapy which resulted in the delivery of 20 healthy babies and 1 abortion. Remaining 2 had 3 pregnancies maintained with heparin, resulting in 2 healthy babies and 1 spontaneous abortion. RESULT: Among 16 women with mechanical heart valves, there were 7 pregnancies during which warfarin was used and this was associated with 4 fetal wastages(2 therapeutic abortion, 1 spontaneous abortion and 1 stillbirth with cerebral hemorrhage). However, in pregnancies where heparin was used, there was no fetal wastage. A patient who did not take anticoagulant for the first trimester and took warfarin for the remaining period and a patient who did not take anticoagulant during pregnancy delivered normal babies. There was an other fetal wastage in a patient on anti-platelet therapy for the first trimester and warfarin therapy for the remaining periods. There was 1 minor petechial complication in a heparin administered group. CONCLUSION: The study indicates that woman with bioprosthetic heart valves can go through pregnancy without undue risks or complications. On the other hand, the use of warfarin during pregnancy in women with mechanical heart valves, was shown to be associated with unacceptable high risk for the fetus. However, in the same group of women, judicious use of heparin during pregnancy was accompanied by a much reduced risk. The safety and adequate therapeutic range of heparin usage under such circumstances are subject to further studies.

The Clinical Experiences of Patch Angioplasty in Isolated Critical Left Main Coronary Artery Stenosis / 대한흉부외과학회지

The conventional surgical treatment of isolated critical stenosis of the left main coronary artery restores a less physiologic perfusion of the myocardium, leads to occlusion of the left coronary ostium, and consumes an appreciable length of bypass material. From June 1994 to February 1996, eleven patients, three male and eight female, underwent patch angioplasty and additional bypass graft to left anterior descending artery (10 internal mammary artery, 1 saphenous vein) in isolated critical left main coronary artery stenosis. Their ages ranged from 34 to 62 years, mean 44 years. All had 60% to 90% stenosis of the left main coronary artery and Class III angina. The angiogram showed nine osteal lesion and three main stem stenosis. The operation was performed with conventional cardiopulmonary bypass and cold blood cardioplegia. We approached anteriorly and used bovine pericardium as onlay patch in all patients. There were one leg wound dehiscence, but no operative deaths and infarctions. All patients are free of symptoms after a mean follow-up of 15.5 months. Angiographic restudy at an average 14.4 months was obtained in five patients and showed widely patent left main coronary artery with excellent runoff. But additional graft to left anterior descending coronary artery were stenosed in two patients and showed diminutive flow in others. Our preliminary results suggest that angioplasty of the left main coronary artery can be carried out with low operative risks. But additional bypass graft to left anterior descending coronary artery may be unnecessary. The technique appears to be a promising alternative to conventional coronary artery bypass grafting in isolated left main coronary artery stenosis.

Prediction of Improvement of Hibernating Myocardium after Coronary Artery Bypass Grafting: The role of dobutamine stress echocardiography / 대한흉부외과학회지

BACKGROUND: In patients with coronary artery disease, dysfunctional hypoperfused myocardium at rest may represent either nonviable or viable hibernating myocardium. Two-dimensional echocardiography can detect regional wall motion abnormalities resulting from myocardial ischemia by dobutamine infusion. The purpose of the present study was to identify the prediction of improvement of regional left ventricular (LV) function after surgical revascularization. MATERIALS AND METHODS: Sixteen patients with chronic regional LV dysfunction underwent dobutamine stress echocardiography (DSE) (dobutamine: baseline, 5, 10, 20microgram/kg/min) before coronary artery bypass grafting (CABG) and underwent echocardiography at least 2 months after CABG. RESULTS: All patients were male with mean age of 58 years ranging from 42 to 73 years. The mean LV ejection fraction was 41.8% with a range from 19% to 55%. During DSE, there were no complications, also, there were no operative morbidities or mortalities. Improvement of wall motion within the dysfunctional myocardium was found in 8 (50%) of 16 patients in DSE. Among them, 6 patients (75%) showed functional recovery after CABG. Another 8 patients did not show improvement of wall motion in DSE. But among them, 3 patients (38%) showed functional recovery after CABG. 84 dysfunctional segments were found in 256 segments of 16 patients. Improvement of wall motion was found in 34 of 84 segments in DSE. Among them, 23 segments (74%) showed functional recovery after CABG. Another 53 segments did not show improvement of wall motion in DSE. But among them, 12 segments (23%) showed functional recovery after CABG. The sensitivity and specificity of DSE for the prediction of postoperative improvement of segmental wall motion were 66% and 84%, respectively. The positive and negative predictive value of DSE were 74% and 77%, respectively. In patients with chronic regional LV dysfunction, think that DSE is a good predictor of the improvement of dysfunctional segments after CABG.

The Comparison of Protective Effects of Adenosine Included Cardioplegia According to Adenosine Dosage / 대한흉부외과학회지

BACKGROUND: Adenosine is secreted by myocardial cells during myocardial ischemia or hypoxia. It has many beneficial effects on arrhythmias, myocardial ischemia, and reperfusion ischemia. Although many investigators have demonstrated that cardioplegia that includes adenosine shows protective effects in myocardial ischemia or reperfusion injury, reports of the optimal dose of adenosine in cardioplegic solutions vary. We reported the results of beneficial effects of single dosage (0.75 mg/Kg/min) adenosine by use of self-made Langendorff system. But it is uncertain that dosage was optimal. The objective of this study is to determine the optimal dose of adenosine in cardioplegic solutions. MATERIAL AND METHOD: We used a self-made Langendorff system to evaluate the myocardial protective effect. Isolated rat hearts were subjected to 90 minutes of deep hypothermic arrest (15degree C) with modified St. Thomas' Hospital cardioplegia including adenosine. Myocardial adenosine levels were augmented during ischemia by providing exogenous adenosine in the cardioplegia. Three groups of hearts were studied: (1) group 1 (n=10) : adenosine -0.5 mg/Kg/min, (2) group 2 (n=10): adenosine -0.75 mg/Kg/min, (3) group 3 (n=10) : adenosine -1 mg/Kg/min. RESULT: Group 3 resulted in a significantly rapid arrest time of the heart beat (p<0.05) but significantly slow recovery time of the heart beat after reperfusion (p<0.05) compared to groups 1 and 2. Group 2 showed a better percentage of recovery (p<0.05) in systolic aortic pressure, aortic overflow volume, coronary flow volume, and cardiac output compared to groups 1 and 3. Group 1 showed a a better percentage of recovery (p<0.05) in the heart rate compared to the others. In biochemical study of drained reperfusates, CPK and lactic acid levels did not show significant differences in all of the groups. CONCLUSION: We concluded that group 2 [adenosine (0.75 mg/Kg/min) added to cardioplegia] has better recovery effects after reperfusion in myocardial ischemia and is the most appropriate dosage compared to group 1 and 3.

Animal Experiment and Blood Biocompatibility Study of Polymer Valve / 대한흉부외과학회지

In vivo testings of the monoleaflet polymer valve were performed in seven dogs to prove its blood biocompatibility. The monoleaflet polymer valve used in this study was developed for short-term usage n the ventricular assist device. The frame and leaflet of the polymer valve were made of polyurethane. The inter-aortic valved conduit were implanted in four dogs and the ventriculo-atrial valved conduit was implanted in one dog. The ventricular assist devices with polymer valve were implanted in two dogs. The longest survival was 20 days. Main causes of death were bleeding and infection. To examine the blood compatibility, each blood sample was collected and RBC, WBC, hematocrit, hemoglobin, platelet and lactic acid dehydrogenase were analyzed. These studies thus far demonstrated that, with further development, a reliable and inexpensive polymer valve will be used in the ventricular assist device as short term usage.

Utility of Quantification of Coronary Artery Calcification Using Spiral CT

PURPOSE: To evaluate the utility of quantification of coronary artery calcification using spiral CT. MATERIALS AND METHODS: Spiral CT scans of the heart were obtained in 25 patients with coronary artery disease diagnosed by coronary angiography and in six controls without coronary artery disease. Spiral CT was performedwith 3 mm collimation at 3 mm/sec table speed and the obtained volume data of the heart was reconstructed at 2 mm intervals. Total calcium scores of the 30 contiguous slices of the proximal coronary artery were calculated basedon the areas and peak density. Two groups were compared for total scores and sensitivity, and specificity and positive predictive values were calculated. RESULTS: The number of subjects with coronary calcification(totalcalcium score>0) detected by spiral CT were 20(80%) of 25 with coronary artery disease and 2(33%) of 6 without coronary artery disease. The sensitivity, specificity, and positive predictive values were 80%, 67% and 91% respectively. Sensitivity was 64%, specificity was 80% in patients aged < or =60. Sensitivity was 76% and specificity was 83%(total calcium score 10). CONCLUSION: Quantification of coronary artery calcification using spiral CT haslow specificity in the older group and low sensitivity in the younger group ; the procedure is therefore may notbe useful as a non invase screening test to predict the prescence of coronary artery disease. In the younger group, however, a cardiac workup is strongly indicated if calcification is present.