摘要:

Pulmonary vascular disease, a serious complication of many congenital heart lesions, has three major components: increased muscularity of small pulmonary arteries; intimal hyperplasia, scarring and thrombosis; and reduced numbers of intraacinar arteries. The muscularity is due to increased stress on the vessel wall, and is reversible. The intimal changes may be due to endothelial damage, causing an imbalance between prostacyclin and thromboxane A2 production and leading to local platelet aggregation. This, in turn, may stimulate migration and division of myointimal cells, which thicken the intima and lead to scarring and thrombosis. Extensive intimal changes are probably irreversible, but the possibility of preventing them by use of agents that inhibit platelet aggregation needs to be considered. The mechanism of a decrease in numbers of intraacinar arteries is unexplained. The potential for growth of new vessels after corrective surgery of the cardiac defect is an important factor in restoring pulmonary vascular resistance to normal. Available evidence suggests that this growth potential is reduced after 2 years of age and argues for early surgical relief of pulmonary vascular stresses.

ISSN:0009-7322    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Work-function curves relating systemic ventricular end-diastolic pressure (EDP) to minute work index (MWI) were used to assess ventricular performance in eight patients with tetralogy of Fallot (TOF), five patients with ventricular septal defect (VSD), and nine patients with d-transposition of the great arteries (TGA). All patients underwent repair when they were younger than 18 months of age and, when studied 13 months after surgery, were found to have satisfactory anatomic results by catheterization. Results were compared with seven control subjects. All patients had normal systemic ventricular hemodynamics at rest. A work-function curve for each patient was generated using a methoxamine infusion to increase afterload and measuring EDP, mean ventricular systolic pressure and cardiac index. Heart rate was maintained within a narrow range for each patient.The systemic ventricle in the TGA patients responded to the afterload stress with a smaller increase in MWI than was noted for either the TOF (p < 0.05), VSD (p < 0.01) or control (p < 0.01) groups. This difference in MWI for the TGA patients occurred despite a comparable increase in systemic ventricular EDP for all groups. The net result was a highly significant difference in mean slope of the work-function curves for the TGA patients compared with the TOF (p < 0.02), VSD (p < 0.01) or control (p < 0.01) patients. There was no significant difference in mean slope for the TOF, VSD and control groups.Thus, an afterload stress at early postoperative follow-up identified preclinical systemic ventricular dysfunction in TGA patients not evident in age-matched TOF and VSD patients. This finding takes on added significance with the recent development of alternative surgical approaches to repair of TGA that use the left ventricle as the systemic pumping chamber.

ISSN:0009-7322    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

A dilatable form of bilateral branch pulmonary artery stenosis was created in 27 newborn lambs. Nine lambs were long-term survivors and were dilated with modified Gruntzig balloon dilation catheters. They were allowed to recover for 6-9 weeks, during which time there was no significant change in the mean systolic gradients across the narrowed sites. Thirteen arteries underwent dilation. Dilation was associated with a decrease in the systolic gradient in all cases (from 34.9 mm Hg to 8.1 mm Hg) and an increase in the diameter of the narrowed site (from 4.6 to 7.6 mm) as estimated by angiography. Flows and flow distribution were measured in four lambs before and after unilateral dilation using 15-p radiolabeled microspheres; in each case, the fraction of total flow to the dilated lung rose after dilation (19.2 to 45.4%), as did the total flow to the dilated lung (30.0 to 69.2 ml/kg-min). Four lambs were catheterized every 2-4 weeks for an average of 16 weeks after dilation; the average gradient in these lambs remained below 10 mm Hg despite considerable growth (from 9.6 to 25.9 kg). Gross pathologic examination showed an intact vascular adventitia in all cases; there were multiple linear tears in the intima in recently (less than 7 days) dilated cases, but complete intimal healing had occurred by 2 months after dilation. No significant morbidity could be attributed to the dilation procedure. These results indicate that clinical trials are warranted.

ISSN:0009-7322    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

The case reports of 492 infants with critical congenital *-rdiac disease treated with prostaglandin E1 (PGE1) were reviewed to determine the nature and incidence of intercurrent medical events. Forty-three percent of the infants had at least one such event, but only half of these were related to PGE1 and the majority required only minor changes in management. Cardiovascular events were the most common (18% incidence), with cutaneous vasodilation and edema occurring more frequently during intraaortic infusion than during i.v. infusion. Central nervous system events were reported in 16% of the patients. Respiratory depression was reported in 12%, and was particularly common in infants weighing less than 2.0 kg at birth (42%). Hematologic, infectious and renal events appeared for the most part to be unrelated to PGE1. The overall mortality (excluding 19 patients with hypoplastic left-heart syndrome) was 31%; the mortality for the patients with critical coarctation or interruption of the aortic arch was nearly twice that for the cyanotic infants (50% vs 27%). No death was attributed to PGE1 administration.During infusion of PGE1, arterial blood pressure and respiratory activity should be monitored carefully and appropriate supportive steps taken if hypotension or respiratory depression occurs. The development of fever or jitteriness may require reduction of the infusion rate and, in view of the possible increased incidence of infections, the prophylactic use of antibiotics is recommended.

ISSN:0009-7322    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Between January 1976 and June 1979, 492 infants with ductus arteriosus-dependent congenital heart disease (385 cyanotic and 107 acyanotic) received prostaglandin E, (PGE,) in 56 centers in the United States as part of a protocol sponsored by the Upjohn Company. In the infants with cyanotic congenital heart disease, the mean Pao2 for the group increased from 26.7 mm Hg before to 38.5 mm Hg during infusion (p < 0.001). Infants older than age 4 days had a higher preinfusion Pao2 and a smaller increase in Pao2. Infants weighing more than 4 kg at birth and alkalotic infants (pH > 7.45) had a smaller increase in Pao2. No differences in response were found with respect to mode of administration (intra-arterial or i.v.), gender, maternal age, or preinfusion Paco2. PGE, provides excellent palliation for infants with ductus arteriosus- dependent cyanotic congenital heart disease.Of the 107 infants with acyanotic congenital heart disease, 46 had juxtaductal coarctation and 34 had interruption of the aortic arch. Clinical improvement occurred in about 80% in each group. In the infants with aortic interruption, descending aortic blood pressures increased and the pressure differences across the ductus arteriosus decreased markedly. In the infants with coarctation, descending aortic blood pressures increased and ascending aortic pressure decreased. The systolic pressure difference across the coarctation decreased markedly, from 45 to 9 mm Hg. Infants in whom the ductus arteriosus was closed before the infusion showed no beneficial effects. In infants in whom a constricted ductus arteriosus relaxed, the effect occurred more slowly than in infants with cyanotic heart disease. PGE, also provides excellent palliation in infants with aortic obstruction in which lower body perfusion is dependent on the ductus arteriosus.

ISSN:0009-7322    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

The hemodynamic and antithrombotic properties of prostacyclin (PGI2) were evaluated in an in vivo canine model in which left circumflex coronary artery (LCX) thrombus formation was initiated by electrical stimulation (150 iA, DC for 6 hours) of the artery's intimal surface via an implanted silver wire electrode. Eleven of the 12 control dogs (92%) developed totally occlusive LCX thrombi after an average of 3.2 + 0.4 hours of LCX stimulation; the remaining control dog underwent spontaneous ventricular fibrillation.A PGI2 infusion (150, 300 or 500 ng/kg/min) into the left atrial appendage was begun 10 minutes before the start of LCX stimulation and continued throughout the 6-hour stimulation period. LCX thrombus wet weight and the incidence of occlusive LCX thrombosis decreased in the PGI2-treated dogs in a dose-dependent manner. Hemodynamically, after 6 hours of PGIs infusion at 500 ng/kg/min, mean arterial pressure decreased by 36 ± 4%, cardiac output increased by 51 ± 14%, and the effect on heart rate was inconsistent. Light and scanning electron microscopic examination of the LCX at the site of electrode insertion in PGI2- treated dogs (500 ng/kg/min) revealed a damaged and denuded. intimal surface but no thrombi, in contrast to the thrombus formation in similar specimens taken from control dogs. In this report, we describe the potent hemodynamic effects of prolonged PGI2 infusion and demonstrate its ability to prevent coronary artery thrombosis in response to intimal injury.

ISSN:0009-7322    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

We investigated the effect of i.v. dipyridamole, a potent small-vessel coronary vasodilator, on myocardial infarct size in conscious dogs. Dipyridamole, 7-9.7, ug/kg; 15 dogs) or saline (15 dogs) was infused for 6 hours beginning 10 minutes after acute permanent occlusion of the mid-circumflex coronary artery. After sacrifice, 48 hours after occlusion, stereoscopic postmortem angiography was used to define the mass of the occluded coronary bed. Infarct size was determined by planimetry of weighed, unstained left ventricular slices. Dipyridamole produced a striking reduction in mean infarct mass compared with control (3.1 g vs 13.2 g, p < 0.001), while mean occluded bed mass was similar (30.3 g vs 32.7 g, NS). As a percentage of the occluded bed, mean infarct size was reduced from 36.8% to 8.6% (p < 0.001). Mean arterial blood pressure declined approximately 10% after dipyridamole. Heart rate and left atrial pressure did not change significantly. Collateral blood flow, measured with 8-M radioactive microspheres, increased in all regions during dipyridamole infusion. The infarct center and border regions had sustained increases over 6 hours of 23-80%, while nonischemic regions demonstrated a diminishing response over time, with a large (98-125%) increase 10 minutes after infusion and a smaller (22-25%) increase 6 hours later. Although antiplatelet or local metabolic effects cannot be excluded, the myocardial salvage produced by dipyridamole was most likely due to the increase in collateral blood flow.

ISSN:0009-7322    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Visual interpretation of stress-redistribution thallium-201 (201T1) scintigrams is subject to observer variability and is suboptimal for evaluation of extent of coronary artery disease (CAD). An objective, computerized technique has been developed that quantitatively expresses the relative space-time myocardial distribution of 201TI. Multiple-view, maximum-count circumferential profiles for stress myocardial distribution of 201T1 and segmental percent washout were analyzed in a pilot group of 31 normal subjects and 20 patients with CAD to develop quantitative criteria for abnormality. Subsequently, quantitative analysis was applied prospectively to a group of 22 normal subjects and 45 CAD patients and compared with visual interpretation of scintigrams for detection and evaluation of CAD. The sensitivity and specificity of the quantitative technique (93% and 91%, respectively) were not significantly different from those of the visual method (91% and 86%). The quantitative analysis significantly (p < 0.05) increased the sensitivity of 20'Tl imaging over the visual method in the left anterior descending artery (from 56% to 80%), left circumflex artery (from 34% to 63%) and right coronary artery (from 65% to 94%) without significant loss of specificity. Using quantitative analysis, sensitivity for detection of diseased vessels did not diminish as the number of vessels involved increased, as it did with visual interpretation. In patients with one-vessel disease, 86% of the lesions were detected by both techniques; however, in patients with three-vessel disease, quantitative analysis detected 83% of the lesions, while the sensitivity was only 53% for the visual method. Seventy percent of the coronary arteries with moderate (50-75%) stenosis were detected quantitatively, compared with 35% by the visual method.We conclude that this quantitative technique for analysis of stress-redistribution 201T1 scintigrams is objective and more sensitive than the visual method, especially in patients with multiple-vessel disease and those with moderate coronary artery stenosis.

ISSN:0009-7322    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Thallium-201 (I'TI) redistribution scintigraphy might differentiate reversibly from nonreversibly asynergic myocardial segments and thus predict the response of these segments to coronary artery bypass grafting (CABG). To test this hypothesis, 25 consecutive patients undergoing CABG, preoperative stress-redistribution 2'lTI scintigraphy, and both pre- and postoperative resting equilibrium radionuclide Yentriculography were evaluated. For both types of scintigraphic study, each patient was imaged in the same three views. Because of the effects of CABG on septal motion, this region was considered separately.Postoperative improvement was noted in 54% of 72 preoperative asynergic segments. Improvement was common not only in hypokinetic but also in akinetic and dyskinetic segments, and occurred in a similar proportion of studies performed early (less than 2 weeks) or late (3-6 months) after CABG. Thallium-201 redistribution scintigraphy was highly predictive of the pattern of postoperative asynergy: The redistribution pattern was normal in 90% of segments with reversible asynergy and abnormal in 76% of segments with nonreversible asynergy. The presence or absence of pathologic Q waves was less sensitive in this differentiation. Septal segments, however, frequently demonstrated abnormal wall motion postoperatively, despite normal 20'Tl redistribution scintigraphy. Resting left ventricular ejection fraction (LVEF) was generally unchanged postoperatively, but in some patients with multiple areas of reversible asynergy it did improve.Thus, 20'TI redistribution scintigraphy appears to reliably distinguish viable from nonviable asynergic myocardial zones, and predicts the response of these segments to CABG.

ISSN:0009-7322    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

We evaluated changes in ventricular wall motion after surgery by comparing smoothed, filtered measurements of regional percent shortening (RPS) from right anterior oblique ventriculograms in 37 patients before and after surgery. After surgery there was a significant (p < 0.05) decrease in the number of regions with hypokinetic wall motion. The distribution of RPS values was also different (p < 0.005). However, the mean value of RPS for the surgery group as a whole was not significantly altered. These data were contrasted with RPS data from 11 control patients, who were each studied twice but did not have surgical intervention. Similar analysis of the control group did not show any significant change between studies in the number of hypokinetic regions, and the distributions of RPS for the first and second angiograms were not different. We found a 10.3% absolute mean change in repeated measurements of RPS in the control group.We conclude that significant changes occurred after surgery that were not evident in the control group, and the amount of variability in repeated measurements of RPS suggests that analysis should be applied to group rather than individual data.

ISSN:0009-7322    

出版商:OVID    

年代:1981

数据来源: OVID