Importance of luxury flow for critically ill patients receiving a left ventricular assist system

The presence of a significant organ dysfunction does not immediately exclude patients from consideration for treatment with a left ventricular assist system (LVAS). However, in treating morbid circulatory shock patients with multiple organ failure, it is important to know the preoperative and postoperative factor or factors related to the recovery of the damaged organ function. In this study, we retrospectively analyzed patients receiving a LVAS at our institution and tried to determine the important factors related to the survival of patients with multisystem failure. Twenty-seven patients who underwent LVAS placement at Saitama Medical School Hospital between 1993 and 2003 were included in this study. The preoperative risk factors analyzed were renal dysfunction, respiratory dysfunction, hepatic dysfunction, the existence of active infection, and the combination of all four factors. As a postoperative factor, the pump flow index (mean LVAS pump flow during the first 2 weeks after LVAS surgery divided by the body surface area) was analyzed. None of the analyzed preoperative factors could predict survival after LVAS surgery, but a pump flow index of less than 2.5 l/min/m² had a significant relationship with death after LVAS surgery. Further analysis revealed that all the patients with a pump flow index of 3.0 l/min/m² or more could overcome preoperative organ dysfunction. Congestive heart failure patients with multisystem failure need luxury pump flow for successful LVAS surgery; this factor could be especially important in device selection and postoperative management.     

Correlation between preoperative ischemia and major cardiac events after peripheral vascular surgery

Patients who undergo peripheral vascular surgery are at increased risk for postoperative cardiac events and are difficult to assess preoperatively because of limitations on their activity. We prospectively studied 176 consecutive eligible patients undergoing elective vascular surgery to determine the value in predicting a postoperative cardiac event of preoperative electrocardiographic monitoring to detect myocardial ischemia. Of the 176 patients, 32 (18 percent) had 75 episodes of monitored ischemic ST-segment depression preoperatively (of which 73 were asymptomatic), and 13 (7 percent) met strict criteria for major postoperative cardiac events, including 1 with a fatal myocardial infarction, 3 with nonfatal infarctions, 4 with unstable angina, and 5 with ischemic pulmonary edema. Of the 32 patients with ischemia before their operations, 12 had postoperative events (univariate relative risk, 54; 95 percent confidence interval, 7.2 to 400). Only 1 postoperative event occurred among 144 patients who did not have preoperative ischemia. The sensitivity of preoperative ischemia was 92 percent, the specificity 88 percent, the predictive value of a positive result 38 percent, and the predictive value of a negative result 99 percent. In multivariate analyses, preoperative ischemia was the most significant correlate of postoperative cardiac events and remained a statistically significant independent correlate even after we had controlled for all other preoperative factors (multivariate relative risk, 24.4; 95 percent confidence interval, 6.8 to 88). These preliminary data suggest that preoperative electrocardiographic monitoring to detect episodes of myocardial ischemia is a useful method for assessing cardiac risk in patients who undergo elective vascular surgery. In particular, the absence of ischemia during monitoring indicates a very low risk.     

Doppler measurement of cardiac output across prosthetic mitral valves

Summary In 46 patients with a normal functioning mitral valve prosthesis (15 St. Jude, 19 Medtronic Hall, 12 Hancock) cardiac output was measured by pulsed Doppler echocardiography across the valve prosthesis. Simultaneously cardiac output was determined by thermodilution or pulsed Doppler echocardiography in the left ventricular outflow tract (2.8 l/min–9.5 l/min). The prosthetic valve area was calculated using the pressure half-time method. Cardiac output was calculated by multiplying time-velocity integrals with the mitral valve area. Cardiac output measurements across the mitral prosthesis correlated significantly with thermodilution (r=0.96, SEE=0.400 l/min) and pulsed Doppler echocardiography flow measurements in the left ventricular outflow tract (r=0.82, SEE=0.679 l/min). The mean percent error of the Doppler transmitral flow measurement was 10.8%. Doppler transmitral flow underestimated cardiac output values of more than 6.5 l/min in 6 of 7 patients. Cardiac output measurements across Hancock (SEE=0.473 l/min) and St. Jude prostheses (SEE=0.538 l/min) were more accurate than across Medtronic Hall prostheses (SEE=0.847 l/ min).Cardiac output can be calculated by pulsed Doppler echocardiography across normal functioning mitral prostheses. Due to the different flow dynamics the accuracy of cardiac output measurement depends on the prosthetic valve type. Reliable measurements of cardiac output can be performed across Hancock and St. Jude prostheses only. This method is limited in volume flow measurements across Medtronic Hall prostheses.     

The use of artificial neural networks to stratify the length of stay of cardiac patients based on preoperative and initial postoperative factors

BACKGROUND: The limitations of current prognostic models in identifying postoperative cardiac patients at risk of experiencing morbidity and subsequently an extended intensive care unit length of stay (ICU LOS) is well recognized. This coupled with the desire for risk stratification in order to prioritize medical intervention has lead to the need for the development of a system that can accurately predict individual patient outcome based on both preoperative and immediate postoperative clinical factors. The usefulness of artificial neural networks (ANNs) as an outcome prediction tool in the critical care environment has been previously demonstrated for medical intensive care unit (ICU) patients and it is the aim of this study to apply this methodology to postoperative cardiac patients. METHODS: A review of contemporary literature revealed 15 preoperative risk factors and 17 operative and postoperative variables that have a determining effect on LOS. An integrated, multi-functional software package was developed to automate the ANN development process. The efficacy of the resultant individual ANNs as well as groupings or ensembles of ANNs were measured by calculating sensitivity and specificity estimates as well as the area under the receiver operating curve (AUC) when the ANN is applied to an independent test dataset. RESULTS: The individual ANN with the highest discriminating ability produced an AUC of 0.819. The use of the ensembles of networks technique significantly improved the classification accuracy. Consolidating the output of three ANNs improved the AUC to 0.90. CONCLUSIONS: This study demonstrates the suitability of ANNs, in particular ensembles of ANNs, to outcome prediction tasks in postoperative cardiac patients.     

Calcium sensitivity and unloaded shortening velocity of hypertrophied and non-hypertrophied skinned human atrial fibres

The mechanical properties of myocardium of different animals are modified by a chronic increase in haemodynamic load. In this study differences in calcium sensitivity and maximum unloaded shortening velocity of hypertrophic and non-hypertrophic chemically skinned human atrial fibres are characterized. Investigating right atria of 34 patients, possible correlations are studied between preoperative atrial pressure, degree of hypertrophy (estimated from the muscle fibre diameter), calcium responsiveness (pCa₅₀ eliciting half-maximum contraction) and V _max (unloaded shortening velocity). Hypertrophic fibres from atrial appendages of patients having an increased right atrial pressure (RAP 8.5±1.6 mm Hg) and suffering from mitral valve disease (stenosis and insufficiency combined) had a fibre diameter of 18.0±0.9 m. They also had a higher calcium sensitivity (pCa₅₀ 5.65±0.08) and a lower unloaded shortening velocity (1.7±0.1 muscle lengths/s) than non-hypertrophic fibres from the appendages of patients with normal right atrial pressure (RAP 3.2±0.5 mm Hg) and coronary heart disease (CHD: pCa₅₀ 5.45±0.04; V _max= 3.4±0.2 muscle lengths/s; fibre diameter 12.8±0.4 m). Thus non-hypertrophic fibres from control CHD patients differed significantly (p < 0.01) from hypertrophied atrial fibres of patients with mitral valve disease and with combined valve disease (MAV, pCa₅₀=5.58±0.05, V _max 2.0±0.3 muscle lengths/s, fibre diameter 14.6±0.9 m) or aortic valve disease (stenosis combined with insufficiency, fibre diameter 14.8±1.4 m, pCa₅₀ 5.56±0.03, V _max 2.0±0.24 muscle lengths/s; RAP 11.0±2.6 mm Hg). Such alterations of calcium responsiveness, shortening velocity and fibre thickness may reflect an adaptation to the chronic overload in atria from patients with various forms of heart valve disease.     

Determination of cardiac risk by dipyridamole-thallium imaging before peripheral vascular surgery

To evaluate the severity of coronary artery disease in patients with severe peripheral vascular disease requiring operation, we performed preoperative dipyridamole-thallium imaging in 54 stable patients with suspected coronary artery disease. Of the 54 patients, 48 had peripheral vascular surgery as scheduled without coronary angiography, of whom 8 (17 per cent) had postoperative cardiac ischemic events. The occurrence of these eight cardiac events could not have been predicted preoperatively by any clinical factors but did correlate with the presence of thallium redistribution. Eight of 16 patients with thallium redistribution had cardiac events, whereas there were no such events in 32 patients whose thallium scan either was normal or showed only persistent defects (P less than 0.0001). Six other patients also had thallium redistribution but underwent coronary angiography before vascular surgery. All had severe multivessel coronary artery disease, and four underwent coronary bypass surgery followed by uncomplicated peripheral vascular surgery. These data suggest that patients without thallium redistribution are at a low risk for postoperative ischemic events and may proceed to have vascular surgery. Patients with redistribution have a high incidence of postoperative ischemic events and should be considered for preoperative coronary angiography and myocardial revascularization in an effort to avoid postoperative myocardial ischemia and to improve survival. Dipyridamole-thallium imaging is superior to clinical assessment and is safer and less expensive than coronary angiography for the determination of cardiac risk.     

Association of perioperative myocardial ischemia with cardiac morbidity and mortality in men undergoing noncardiac surgery. The Study of Perioperative Ischemia Research Group

BACKGROUND. Adverse cardiac events are a major cause of morbidity and mortality after noncardiac surgery. It is necessary to determine the predictors of these outcomes in order to focus efforts on prevention and treatment. Patients undergoing noncardiac surgery sometimes have postoperative cardiac events. It would be helpful to know which patients are at highest risk. METHODS. We prospectively studied 474 men with coronary artery disease (243) or at high risk for it (231) who were undergoing elective noncardiac surgery. We gathered historical, clinical, laboratory, and physiologic data during hospitalization and for 6 to 24 months after surgery. Myocardial ischemia was assessed by continuous electrocardiographic monitoring, beginning two days before surgery and continuing for two days after. RESULTS. Eighty-three patients (18 percent) had postoperative cardiac events in the hospital that were classified as ischemic events (cardiac death, myocardial infarction, or unstable angina) (15 patients), congestive heart failure (30), or ventricular tachycardia (38). Postoperative myocardial ischemia occurred in 41 percent of the monitored patients and was associated with a 2.8-fold increase in the odds of all adverse cardiac outcomes (95 percent confidence interval, 1.6 to 4.9; P less than 0.0002) and a 9.2-fold increase in the odds of an ischemic event (95 percent confidence interval, 2.0 to 42.0; P less than 0.004). Multivariate analysis showed no other clinical, historical, or perioperative variable to be independently associated with ischemic events, including cardiac-risk index, a history of previous myocardial infarction or congestive heart failure, or the occurrence of ischemia before or during surgery. CONCLUSIONS. In high-risk patients undergoing noncardiac surgery, early postoperative myocardial ischemia is an important correlate of adverse cardiac outcomes.     

Circulation and heart rate variability at three hemodynamic patterns of juvenile age

The study involved 135 apparently healthy students 17 - 21 years old. Bioimpedance tetrapolar rheopolygraphy based on Kentavr computer system was employed in studied subjects in supine position at rest. Examined subjects, regarding their percental volume of cardiac index (CI) - 25 and 75, were included into three groups with hypokinetic (CI was lower than 2.0 L/min/m2), eukinetic (CI ranged from 2.0 to 3.0 L/min/m2) and hyperkinetic (CI was more than 3.0 L/min/ m2) hemodynamic pattern. The evaluation of blood flow indices showed that heart rate, stroke volume, minute blood volume, cardiac index, rheogram amplitude were lower in hypokinetic type, but photoplethysmogram was higher when compared with both eukinetic and hyperkinetic types. Power spectral analysis of heart rate variability demonstrated that components of heart rate power frequencies, absolute values of the heart rate power oscillations at four frequencies ranges (UVLF, VLF, LF, HF) as well as relative values of heart rate power spectrum in LF and VLF were lower, but relative values of high-frequency components were higher compared to other two hemodynamic patterns. These data demonstrate that hypokinetic type of circulation was sparer in healthy subjects of juvenile age.     

Implications of third heart sounds in patients with valvular heart disease. The Veterans Affairs Cooperative Study on Valvular Heart Disease.

BACKGROUND. The presence of third heart sounds in patients with valvular heart disease is often regarded as a sign of heart failure, but it may also depend on the type of valvular disease. METHODS. We assessed the prevalence of third heart sounds and the relation between third heart sounds and cardiac function in 1281 patients with six types of valvular heart disease. RESULTS. The prevalence of third heart sounds was higher in patients with mitral regurgitation (46 percent) or aortic regurgitation (28 percent) than in those with aortic stenosis (11 percent) or mitral stenosis (8 percent). The left ventricular ejection fraction was significantly lower (P less than 0.001) when a third heart sound was detected in patients with aortic stenosis (0.38, vs. 0.56 in those without third heart sounds) or mixed aortic valve disease (0.40 vs. 0.55). However, the ejection fraction was only slightly lower in patients with mitral regurgitation and third heart sounds (0.51 vs. 0.57, P = 0.03). The pulmonary-capillary wedge pressure was higher (P less than 0.001) when a third heart sound was detected in patients with aortic stenosis (18.6 mm Hg, vs. 12.1 mm Hg in those without third heart sounds). There was no association between the wedge pressure and third heart sounds in patients with mitral regurgitation. The prevalence of third heart sounds increased with the severity of mitral regurgitation. CONCLUSIONS. In patients with mitral regurgitation, third heart sounds are common but do not necessarily reflect left ventricular systolic dysfunction or increased filling pressure. In patients with aortic stenosis, third heart sounds are uncommon but usually indicate the presence of systolic dysfunction and elevated filling pressure.     

Outcome in patients with asymptomatic neck bruits

Five hundred asymptomatic patients with cervical bruits were followed prospectively by clinical and Doppler examination for up to four years (mean, 23.2 months) to identify the variables predicting outcome. Thirty-six patients had strokes or transient ischemic attacks, 51 had cardiac ischemic events, and 45 died. At one year the incidence of cerebral ischemic events (transient ischemic attacks and strokes) was 6 percent, that of cardiac ischemic events was 7 percent, and that of death was 4 percent. The overall incidence of stroke at one year was 1.7 percent (1 percent in patients without previous transient ischemic attacks), but the incidence was 5.5 percent in patients with severe carotid-artery stenosis (greater than 75 percent). Cerebral ischemic events were most frequent in patients with severe carotid-artery stenosis (P less than 0.0001), progressing carotid-artery stenosis (P less than 0.0005), or heart disease (P less than 0.0005) and in men (P less than 0.025). The degree of carotid-artery stenosis on initial presentation was a powerful predictor of neurologic sequelae. Patients with asymptomatic cervical bruits have a higher risk of a cardiac ischemic event than of a stroke. Although the risk of cerebral ischemic events is highest in patients with severe carotid-artery stenosis, in most instances even these patients do not have strokes without some warning.     

Predictors of long-term outcome after percutaneous balloon mitral valvuloplasty.

BACKGROUND. Percutaneous balloon mitral valvuloplasty is known to produce short-term hemodynamic and symptomatic improvement in many patients with mitral stenosis. Comprehensive assessment of the clinical usefulness of balloon valvuloplasty requires evaluation of patients' long-term outcomes. METHODS. We performed balloon mitral valvuloplasty in 146 patients between October 1, 1985, and October 1, 1991. Base-line demographic, clinical, echocardiographic, and hemodynamic variables were evaluated in order to identify predictors of long-term event-free survival. RESULTS. Balloon mitral valvuloplasty was completed successfully in 136 (93 percent) of the patients in whom the procedure was attempted; it resulted in an increase in the mean (+/- SD) mitral-valve area from 1.0 +/- 0.4 to 2.1 +/- 0.9 cm2 and a decrease in the mean transmitral pressure gradient from 14 +/- 5 to 6 +/- 3 mm Hg (P < 0.001 for both comparisons). The estimated overall five-year survival rate was 76 +/- 5 percent, and the estimated five-year event-free survival rate (the percentage of patients without mitral-valve replacement, repeat valvuloplasty, or death from cardiac causes) was 51 +/- 6 percent. According to multivariate Cox proportional-hazards analysis, the independent predictors of longer event-free survival were a lower mitral-valve echocardiographic score (a measure of mitral-valve deformity; range, 0 for a normal valve to 16 for a seriously deformed valve; P < 0.001), lower left ventricular end-diastolic pressure (P = 0.001), and a lower New York Heart Association (NYHA) functional class (P = 0.04). Patients with no risk factors for early restenosis or only one risk factor (echocardiographic score > 8, left ventricular end-diastolic pressure > 10 mm Hg, or NYHA functional class IV) had a predicted five-year event-free survival rate of 60 to 84 percent, whereas patients with two or three risk factors had a predicted five-year event-free survival rate of only 13 to 41 percent. CONCLUSIONS. Balloon mitral valvuloplasty as a treatment for selected patients with mitral stenosis has good long-term results. The long-term outcome after this procedure can be predicted on the basis of patients' base-line characteristics.     

脊柱减压固定融合术后症状性心血管事件发生率及危险因素分析

目的 分析脊柱减压固定融合术后症状性心血管事件(SMI)的发生率及危险因素,为手术方案制定和临床决策提供参考。方法 回顾性分析2015年1月—2016年12月河北医科大学第三医院脊柱外科接受脊柱减压、固定、融合手术治疗的462例患者临床资料,依据住院期间是否发生SMI分为观察组(61例)和对照组(401例)。比较两组患者一般资料、术前心脏功能评估指标、手术因素、术后因素。采用二分类logistic回归分析探讨术后SMI发生的危险因素。结果 462例患者中61例(13.2%)术后发生SMI。与对照组比较,观察组的年龄更大 (60.7岁∶52.3岁)、心肌缺血病史和心脏手术史占比更高(分别为24/61∶50/401和 23/61∶23/401)、颈椎手术占比也更高 (38/61∶168/401),而术中舒张压 (77.0 mmHg∶80.5 mmHg, 1 mmHg=0.133 kPa)、术后次日血清Ca²⁺浓度则较低 (2.2 mol/L∶2.3 mol/L),差异均有统计学意义(P值均＜0.05)。logistic回归分析显示:术后次日血清Ca²⁺浓度低于2.2 mmol/L、心脏手术史、年龄＞55岁与SMI发生具有显著相关性(P值均＜0.05)。结论 脊柱减压固定融合术后SMI的发生率为13.2%,危险因素包括患者年龄＞55岁、术后低血钙和心脏手术史。对于老年患者和既往行心脏手术的患者,术前需详细告知风险,术后监测电解质是必要的。     

Mitral annular calcification and the risk of stroke in an elderly cohort.

BACKGROUND. Previous clinical studies have suggested that there is an association between mitral annular calcification and the risk of stroke, but it is unclear whether this association is independent of the traditional risk factors for stroke. We examined the relation between mitral annular calcification and the incidence of stroke in a population-based study. METHODS. Subjects in the Framingham Study receiving a routine examination underwent M-mode echocardiography to determine the presence and severity (thickness in millimeters) of mitral annular calcification. The incidence of stroke during eight years of follow-up was analyzed with a proportional-hazards model adjusting for the calcification, age, sex, systolic blood pressure, diabetes mellitus, cigarette smoking, atrial fibrillation, and coronary heart disease or congestive heart failure. RESULTS. Among 1159 subjects whose echocardiograms could be assessed for mitral annular calcification and who had no history or current evidence of stroke at the index examination (51 percent of all subjects), the prevalence of mitral annular calcification was 10.3 percent in the men and 15.8 percent in the women. Multivariate analysis demonstrated that the presence of mitral annular calcification was associated with a relative risk of stroke of 2.10 (95 percent confidence interval, 1.24 to 3.57; P = 0.006). There was a continuous relation between the incidence of stroke and the severity of mitral annular calcification; each millimeter of thickening as shown on the echocardiogram represented a relative risk of stroke of 1.24 (95 percent confidence interval, 1.12 to 1.37; P less than 0.001). Furthermore, even when subjects with coronary heart disease or congestive heart failure were excluded from the analysis, subjects with mitral annular calcification still had twice the risk of stroke. CONCLUSIONS. In an elderly, longitudinally followed population-based cohort, mitral annular calcification was associated with a doubled risk of stroke, independently of traditional risk factors for stroke. Whether such calcification contributes causally to the risk of stroke or is merely a marker of increased risk because of its association with other precursors of stroke remains unknown.     

与多普勒超声相结合的人体二尖瓣狭窄下游湍流剪应力二维有限元分析

目的 探讨一种与多普勒超声相结合的人体二尖瓣狭窄下游湍流剪应力地维有限元分析方法。方法 采用多普勒超声无创检测技术,将体内实时采集到的左心腔二维超声图像和左房、左室壁平均运动速度作为边界条件,对一组二尖瓣狭窄病人随访期间二尖瓣下游湍流剪应力（turbulent shear stress,TSS)进行计算机数值模拟、二维有限元分析。结果 有限元分析显示：TSS在两次随访前后均存在显著性差异（P＜0．05）,与瓣膜病变Wilkins评分呈明显正相关（r:0.80-0.82);无论病变和狭窄程度怎样,跨瓣血流核心区位点TSS始终低于边界各位点,其最大值＜80N／m^2,结果同以往研究结论一致。结论 二尖瓣狭窄下游所产生的TSS与瓣膜病变进展密切相关。有限元法对局部瓣区和整个流场中TSS和速度大小与分布的描述较为完整而详细,因此它与多普勒超声技术相结合,使心瓣流场中TSS的体内定量研究既全面而又准确。     

Pulmonary vascular disease and hypertension after valve surgery for mitral stenosis

The reduction of pulmonary hypertension that occurs within 24 hours of valve replacement for mitral stenosis is well documented, but patients who die after surgery have not been adequately studied. Clinical and autopsy data for 16 patients who died following mitral valve replacement were reviewed. The emphasis was on preoperative and postoperative pulmonary arterial pressure and pulmonary vascular disease, including arterial, venous, and capillary changes. Morphologic features were graded and summed to obtain an additive histologic assessment (AHA). Patients were divided into three groups: 1) those who had uneventful operations and early postoperative periods but died prior to discharge; 2) those who had postoperative difficulty, with identifiable acute anatomic causes of death; and 3) those who had postoperative difficulty, with no apparent acute anatomic cause of death. In group 1 (n = 4) the preoperative pulmonary arterial pressure was 43 +/- 17 mm Hg, and AHA ranged from 0 to 4; in group 2 (n = 5) the preoperative pulmonary arterial pressure was 60 +/- 15 mm Hg, but AHA ranged only from 2 to 5. In group 3 (n = 7) the preoperative pulmonary arterial pressure was 59 +/- 12 mm Hg; AHA ranged from 6 to 9, significantly higher than that of the other groups (P less than 0.005). Three patients from group 3 had elevated pulmonary arterial pressure (60, 52, and 50 mm Hg three, six, and 15 days after surgery, respectively). Two additional patients had right heart failure with normally contracting left ventricles terminally. It is concluded that some patients with mitral stenosis who die after surgery with persistently elevated pulmonary arterial pressure have sufficiently severe pulmonary vascular disease to account for their persistent pulmonary hypertension and death.     

Percutaneous catheter commissurotomy in rheumatic mitral stenosis

We attempted percutaneous transcatheter-balloon mitral commissurotomy in eight children and young adults (9 to 23 years of age) with rheumatic mitral stenosis. The atrial septum was traversed by needle puncture, and an 8-mm angioplasty balloon was advanced over a guide wire. The atrial septal perforation was then dilated to allow passage of the valvuloplasty balloon catheter (18 to 25 mm) across the mitral annulus. Inflation of the transmitral balloon decreased the end-diastolic transmitral gradient temporarily in all patients (from 21.2 +/- 4.0 mm Hg [mean +/- S.D.] to 10.1 +/- 5.5 mm Hg; P less than 0.001). The immediate decrease in the gradient was associated with increases in cardiac output (from 3.8 +/- 1.0 to 4.9 +/- 1.3 liters per minute per square meter of body-surface area; P less than 0.01) and in the calculated mitral-valve-area index (from 0.73 +/- 0.29 to 1.34 +/- 0.32 cm2 per square meter; P less than 0.001). Murmur intensity diminished immediately after commissurotomy in all patients. The greatest reduction in pressure gradient (76 to 95 per cent) occurred when the largest balloon (inflated diameter, 25 mm) was used in the smallest patients (0.9 to 1.2 m2). The balloon commissurotomy produced minimal mitral regurgitation in only one child. Follow-up catheterization (at two to eight weeks) demonstrated persistence of hemodynamic improvement with evidence of partial restenosis in one patient. These early results indicate that balloon mitral commissurotomy can be a safe and effective treatment for children and young adults with rheumatic mitral stenosis.     

Symptoms of Traumatic Stress after Coronary Artery Bypass Grafting

Background: Traumatic stress symptoms have only recently been studied in association with medical treatment procedures. Purpose: The study examined associations of physical and psychological functioning during hospitalization to symptoms of traumatic stress after cardiac surgery. Methods: One hundred thirteen patients admitted for coronary artery bypass grafting participated in the study. Symptoms of traumatic stress were assessed one and six months after surgery, with the Impact of Event Scale. Preoperative stress and ruminative thinking, length of preoperative waiting, duration of surgery, and postoperative recovery indices (length of stay in the intensive care unit, cognitive functioning during intensive care, length of stay in the hospital) were examined. Results: Ten percent of the patients reported severe (> 19) symptoms of avoidance, and five percent reported severe symptoms of intrusion in both follow-ups. Hierarchical regression analyses showed that preoperative stress was positively associated to avoidance symptoms in both follow-ups (p < .01). Preoperative stress and ruminative thinking was positively associated to intrusion symptoms one month after surgery (p < .01). Disease related factors were not related to symptoms of traumatic stress during the postoperative period. Conclusion: This study highlights the role of preoperative surgery-related stress as a risk factor for traumatic stress in the postoperative period.     

Evaluation of the left ventricular reserve by dynamic exercise echocardiography after surgery for valvular heart diseases

Dynamic ergometer exercise in a supine position was applied to 64 patients more than 1 year after valvular heart surgery, and the left ventricular reserve was evaluated echocardiographically. The left ventricular reserve declined in the mitral stenosis-mitral valve replacement group, while it was better maintained in the mitral stenosis-mitral commissurotomy, aortic regurgitation and aortic stenosis groups. The patients were divided into 3 groups depending on whether the percentage increase during exercise of stroke index, an index of left ventricular pump function, increased, unchanged, or decreased. The percentage increase of mean velocity of circumferential fibre shortening (y) and that of left ventricular end-diastolic diameter (x) during exercise were plotted for each group. The increased group was isolated from the unchanged group by the line of y = -5.02x + 30.1; the unchanged group was isolated from the decreased group by that of y = -5.68x-10.0, and the increased and unchanged groups were clearly isolated from the decreased group by that of y = -6.86x-4.76. We conclude that dynamic ergometer exercise echocardiography is useful for evaluating the left ventricular reserve of postoperative patients with valvular heart disease. It was also thought that the subclinical state of cardiac failure can be effectively detected by the present method.     

The causes and risk of stroke in patients with asymptomatic internal-carotid-artery stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators

BACKGROUND: The causes of stroke in patients with asymptomatic carotid-artery stenosis have not been carefully studied. Information about causes might influence decisions about the use of carotid endarterectomy in such patients. METHODS: We studied patients with unilateral symptomatic carotid-artery stenosis and asymptomatic contralateral stenosis from 1988 to 1997. The causes, severity, risk, and predictors of stroke in the territory of the asymptomatic artery were examined and quantified. RESULTS: The risk of stroke at five years after study entry in a total of 1820 patients increased with the severity of stenosis. Among 1604 patients with stenosis of less than 60 percent of the luminal diameter, the risk of a first stroke was 8.0 percent (1.6 percent annually), as compared with 16.2 percent (3.2 percent annually) among 216 patients with 60 to 99 percent stenosis. In the group with 60 to 99 percent stenosis, the five-year risk of stroke in the territory of a large artery was 9.9 percent, that of lacunar stroke was 6.0 percent, and that of cardioembolic stroke 2.1 percent. Some patients had more than one stroke of more than one cause. In the territory of an asymptomatic occluded artery (as was identified in 86 patients), the annualized risk of stroke was 1.9 percent. Strokes with different causes had different risk factors. The risk factors for large-artery stroke were silent brain infarction, a history of diabetes, and a higher degree of stenosis; for cardioembolic stroke, a history of myocardial infarction or angina and hypertension; for lacunar stroke, age of 75 years or older, hypertension, diabetes, and a higher degree of stenosis. CONCLUSIONS: The risk of stroke among patients with asymptomatic carotid-artery stenosis is relatively low. Forty-five percent of strokes in patients with asymptomatic stenosis of 60 to 99 percent are attributable to lacunes or cardioembolism. These observations have implications for the use of endarterectomy in asymptomatic patients. Without analysis of the risk of stroke according to cause, the absolute benefit associated with endarterectomy may be overestimated.     

Post-Fontan care based on hemodynamic characteristics, with special reference to the central venous pressure

Changes in the hemodynamics of six patients having received Fontan-like operations were closely observed during the first 48 h after the operation. Catheterization studies and simultaneous angiocardiography were also performed before and after the operation. Hemodynamic derangement was particularly severe during the first 24 h postoperatively as indicated by a low cardiac output of less than 2.01/min/m2, which persisted in spite of very high central venous pressure. Furthermore, the central venous pressure needed to re-establish the circulation soon after the Fontan procedure significantly correlated with the angiocardiographically assessed preoperative size of distal pulmonary arteries. Accordingly, the preoperative evaluation of the distal pulmonary arterial size is very important, that provides a good guide-line for the degree of circulatory volume expansion necessary to elevate the central venous pressure and to sustain the circulation in the early postoperative period.