Transfusional quality of residual blood from heart—lung machine after extracorporeal circulation

After open-heart surgery using extracorporeal circulation, residual blood from the heart-lung machine was collected, treated by plasmaphaeresis and washed using a Haemonetics Cell Saver. Qualitative, quantitative and bacteriological aspects of the concentrated red cells were studied.

In 13 patients, an average of 500 ml of concentrated washed red cells (CWRC) was obtained with an average haematocrit of 62·3 %; bacteriological cultures were negative in all cases. As far as qualitative aspects were concerned (intraglobular ATP, 2, 3 DPG, deformability, filtrability and resistance to hypotonic solutions), these red cells were always compatible with immediate transfusion. However, the small volume of blood retrieved and the relatively high cost of this technique suggest that its use be restricted to cases of total haemodilution or for patients with rare blood groups, in whom homologous transfusion blood is scarce.

Pulsed laser deposited GeTe-rich GeTe-Sb2Te3 thin films

Pulsed laser deposition technique was used for the fabrication of Ge-Te rich GeTe-Sb2Te3 (Ge6Sb2Te9, Ge8Sb2Te11, Ge10Sb2Te13, and Ge12Sb2Te15) amorphous thin films. To evaluate the influence of GeTe content in the deposited films on physico-chemical properties of the GST materials, scanning electron microscopy with energy-dispersive X-ray analysis, X-ray diffraction and reflectometry, atomic force microscopy, Raman scattering spectroscopy, optical reflectivity, and sheet resistance temperature dependences as well as variable angle spectroscopic ellipsometry measurements were used to characterize as-deposited (amorphous) and annealed (crystalline) layers. Upon crystallization, optical functions and electrical resistance of the films change drastically, leading to large optical and electrical contrast between amorphous and crystalline phases. Large changes of optical/electrical properties are accompanied by the variations of thickness, density, and roughness of the films due to crystallization. Reflectivity contrast as high as ~0.21 at 405 nm was calculated for Ge8Sb2Te11, Ge10Sb2Te13, and Ge12Sb2Te15 layers.

Extracorporeal Circulation as an Additional Method for Cerebral Protection in Simultaneous Carotid Endarterectomy and Coronary Artery Surgical Revascularization

Surgical management of patients with concomitant carotid and coronary artery stenosis remains controversial. Our policy was always to perform at the same time carotid endarterectomy (CE) and coronary artery bypass grafting (CABG), but it was also considered that extracorporeal circulation (ECC), because of full heparinization, hemodilution, pulsatile flow, and hypothermia could provide better cerebral protection during CE. Retrospective data of 124 patients undergoing simultaneous CE and CABGs between January 1994 and December 2001 were reviewed. CE was performed prior to ECC in 65 patients (Group 1-mean age: 70.4 years; sex ratio: 49 male/16 female) and under ECC, prior to CABGs in 59 patients (Group 2-mean age: 69.9 years; sex ratio: 46 male/13 female). Overall hospital mortality was 7.3% (9/124): cardiac-related in 5 patients, or due to septicemia (1 patient), or ARD syndrome (1 patient), or stroke in two others. Univariate analysis demonstrated overweight, unstable angina, and emergency to be significant risk factors. Bilateral carotid stenosis was a significant risk factor of neurologic event when CE was performed prior to ECC (p < 0.05). In Group 1, mortality was 9.2% (6/65), and the incidence of neurologic events was 10.7% (7/65), and was responsible for two of the early deaths in patients with bilateral carotid stenosis. In Group 2, mortality was 5.1% (3/59) but never related to CE, while the neurologic morbidity was 1.7% (1 transient ischemic attack). It is concluded that (1) hospital mortality in patients undergoing simultaneous CE and CABGs was mainly cardiac-related. (2) The combined approach of both localizations appears to be mandatory, when carotid stenosis, even asymptomatic, was hemodynamically significant, or with ulcerative lesions likely to be responsible for embolism. (3) CE, first performed under ECC, appears to be a safe procedure, combining, in terms of cerebral protection, the benefits previously called up. This approach is all the more interesting when carotid stenosis is bilateral; hypothermia < or = 28 degrees C during the carotid clamping time is obviously the optimal method for cerebral protection when ipsilateral or contralateral supply is reduced, or even absent.

Surgery of chronic traumatic aneurysm of the aortic isthmus: benefit of direct suture

OBJECTIVE

Retrospective evaluation of long term results after direct suture repair of chronic traumatic aneurysm of the aortic isthmus.

METHODS

From March 1979 to June 1998, a total of 19 patients with chronic traumatic aneurysm of the aortic isthmus were operated on, among whom 12 (63%) underwent direct suture. These 12 patients (age ranging from 19 to 68 years; mean 34.2 years) constitute the subject of this study. All but one suffered traffic accidents. Mean delay between trauma and surgery was 4 years (range 3 months to 12 years). All patients underwent a left posterolateral thoracotomy through the fourth intercostal space. Extracorporeal circulation for spinal cord protection was installed in six patients (five ilio-iliac shunts, one atrio-iliac shunt). Aortic rupture was partial in five and circumferential in seven patients. The mean clamping time was 25 min. The absence of loss of aortic substance and a careful mobilization of the aorta made the repair by direct suture easier; this technique could thus be achieved in 63.2% of all 19 patients operated on of chronic traumatic aneurysm within the same period.

RESULTS

There was no in-hospital death and no postoperative paraplegia. With a median follow-up of 15 years 3 months (ranging from 22 to 10 years), there were no late complications. Chest X-ray was normal in all patients; eight of them underwent a control angiography between 18 and 72 postoperative months; all these angiographies but one (20% stenosis without gradient) demonstrated a normal appearance of aortic isthmus.

CONCLUSION

Direct suture for repair of chronic traumatic thoracic aneurysm is a safe procedure: long-term outcome was excellent and the complications observed with prosthetic grafts or with aortic endoprosthetic stent-grafts were avoided.

Surgical repair of an aneurysm of the innominate artery with fistulization into the trachea

This report describes a 43-year-old patient presenting with an aneurysm located at the junction between the innominate artery and aorta, with spontaneous fistulization into the trachea. Emergency treatment of this unusually located lesion was undertaken to prevent intratracheal rupture. After ligation of the innominate artery, right common carotid artery, and right subclavian artery due to the risk of infection, the tracheal fistula was treated by direct closure and exclusion using an autologous pericardial flap. The procedure was performed under extracorporeal circulation and circulatory arrest with profound hypothermia.

The short- and mid-term results of bidirectional cavopulmonary shunt with additional source of pulmonary blood flow as definitive palliation for the functional single ventricular heart

OBJECTIVE

The purpose of this study was to demonstrate the early and late outcomes of bidirectional cavopulmonary shunt (BCPS) as a definitive procedure for the functional single ventricular heart.

METHOD

From September 1991 to December 1997, 34 patients underwent a BCPS procedure without a routine conversion to Fontan circulation. The additional source of pulmonary blood flow was left in all patients. Conversion was performed only when it was required for excessive cyanosis.

RESULTS

The hospital mortality rate was 8.8% (3/34, 95% confidence limit; 1.9-23%) and the 5-year survival rate was 75% for a mean follow-up period of 33+/-22 months. Seven patients underwent a conversion procedure for remnant or recurrent cyanosis and deterioration of exercise tolerance. Four of these patients died after conversion to Fontan circulation. Twenty-five long-term survivors with BCPSs maintained an arterial oxygen saturation of 84+/-6.1%, and 52% of them had a normal exercise tolerance or mild limitation. No patients developed severe late complications other than recurrent cyanosis.

CONCLUSION

Due to the high mortality after conversion to Fontan circulation in patients whose conditions had deteriorated, we could not demonstrate the clear superiority of long-term BCPS over the construction of Fontan circulation for management of the functional single ventricular heart. If deteriorated conditions were successfully managed in the late period, the outcome of long-term BCPS would have been better.

Does EuroSCORE work in individual European countries?

OBJECTIVE

Because of national epidemiological differences in adult heart surgery in Europe, the effectiveness and desirability of a pan-European score for the assessment of quality of surgical care remains controversial. We assessed the predictive value of EuroSCORE in national subsets of the EuroSCORE database.

METHODS

The EuroSCORE development data set was divided into national subsets of which those with 500 or more patients were selected for analysis. The Hosmer-Lemeshow goodness-of-fit test was applied to assess the calibration of the EuroSCORE model on individual national samples and the areas under the receiver operating characteristic (ROC) curve were measured to analyse the EuroSCORE discriminative power on individual death prediction.

RESULTS

There were 18676 patients in the six largest national samples: Germany, United Kingdom, Spain, Finland, France and Italy (mean: 3113 patients; range: Finland 1266 to France 4507). Major differences were observed in national distribution of procedures: coronary artery bypass grafting accounted for 77.7% of procedures in Finland but only 46.2% in Spain. The EuroSCORE model goodness-of-fit was satisfactory in all countries (P-value overall: 0.4; UK: 0.34; Finland: 0.87; no values less than 0.05). Areas under ROC curves were 0.81 in Germany, 0.79 in the UK, 0.74 in Spain, 0.87 in Finland, 0.82 in France and 0.82 in Italy.

CONCLUSION

Despite epidemiological differences between European countries, the discriminative power of EuroSCORE was good in Spain and excellent in all other countries. The system, developed from a merged European database, can therefore be used to assess improvement in quality of care achieved by surgeons and institutions as well as for international European comparison in adult heart surgery.

Early and long-term (one-year) effects of the association of aspirin and oral anticoagulant on thrombi and morbidity after replacement of the mitral valve with the St. Jude medical prosthesis: a clinical and transesophageal echocardiographic study

OBJECTIVES

The aim of the study was to test the value of low dose aspirin associated with standard oral anticoagulants (OAC) after mechanical mitral valve replacement (MMRV) to reduce strands, thrombi and thromboembolic events.

BACKGROUND

Strands and thrombi are thought to increase the risk of embolic events after MMVR, particularly in the immediate postoperative period.

METHODS

Two hundred twenty-nine patients were prospectively recruited: 109 patients (group A+) were randomly assigned to aspirin (200 mg per day) with OAC and 120 patients (group A-) to OAC alone (international normalized ratio 2.5 to 3.5). All patients were subjected to multiplane transesophageal echocardiography at nine days and five months and were followed up for one year.

RESULTS

At nine days and five months, there was a high and comparable incidence of strands in the two groups (group A+: 44%, 58%; group A-: 49%, 63%). However, the incidence of nonobstructive periprosthetic valve thrombi was significantly lower in group A+ at 9 days: 5% versus 13%, p = 0.03. Total thromboembolic events were reduced in group A+ (9% vs. 25%, p = 0.004) although there was an increased incidence of gastrointestinal hemorrhage (7% vs. 0%). Overall mortality was 9% in group A+ and 4% in group A-. Valve-related events were similar in both groups. Early thrombi, but not strands, were associated with higher morbidity, especially thromboembolic events (30% vs. 13%, p = 0.003).

CONCLUSIONS

One year after MMVR, the association of aspirin with OAC reduced thrombi and thromboembolic events, but not morbidity, due to an increase in hemorrhagic complications.

Risk factors and outcome in European cardiac surgery: analysis of the EuroSCORE multinational database of 19030 patients

OBJECTIVE

To assess risk factors for mortality in cardiac surgical adult patients as part of a study to develop a European System for Cardiac Operative Risk Evaluation (EuroSCORE).

METHODS

From September to November 1995, information on risk factors and mortality was collected for 19030 consecutive adult patients undergoing cardiac surgery under cardiopulmonary bypass in 128 surgical centres in eight European states. Data were collected for 68 preoperative and 29 operative risk factors proven or believed to influence hospital mortality. The relationship between risk factors and outcome was assessed by univariate and logistic regression analysis.

RESULTS

Mean age (+/- standard deviation) was 62.5+/-10.7 (range 17-94 years) and 28% were female. Mean body mass index was 26.3+/-3.9. The incidence of common risk factors was as follows: hypertension 43.6%, diabetes 16.7%, extracardiac arteriopathy 2.9%, chronic renal failure 3.5%, chronic pulmonary disease 3.9%, previous cardiac surgery 7.3% and impaired left ventricular function 31.4%. Isolated coronary surgery accounted for 63.6% of all procedures, and 29.8% of patients had valve operations. Overall hospital mortality was 4.8%. Coronary surgery mortality was 3.4% In the absence of any identifiable risk factors, mortality was 0.4% for coronary surgery, 1% for mitral valve surgery, 1.1% for aortic valve surgery and 0% for atrial septal defect repair. The following risk factors were associated with increased mortality: age (P = 0.001), female gender (P = 0.001), serum creatinine (P = 0.001), extracardiac arteriopathy (P = 0.001), chronic airway disease (P = 0.006), severe neurological dysfunction (P = 0.001), previous cardiac surgery (P = 0.001), recent myocardial infarction (P = 0.001), left ventricular ejection fraction (P = 0.001), chronic congestive cardiac failure (P = 0.001), pulmonary hypertension (P = 0.001), active endocarditis (P = 0.001), unstable angina (P = 0.001), procedure urgency (P = 0.001), critical preoperative condition (P = 0.001) ventricular septal rupture (P = 0.002), noncoronary surgery (P = 0.001), thoracic aortic surgery (P = 0.001).

CONCLUSION

A number of risk factors contribute to cardiac surgical mortality in Europe. This information can be used to develop a risk stratification system for the prediction of hospital mortality and the assessment of quality of care.

Early and long term results of coronary artery bypass grafts in patients with dialysis dependent renal failure

OBJECTIVE

Coronary artery disease is the main cause of mortality and morbidity in patients on renal therapy replacement. The aim of this study was to define peri-operative risk and long term results of coronary artery bypass grafts (CABG) in dialysis patients.

METHODS

this retrospective study included 82 patients in chronic dialysis who underwent CABG between 1978 and 1997. The mean age was 61+/-10 years (range 28-81 years), 84% of the patients were male and the average duration of dialysis was 57 months (range 1-148 months). Combined procedures were carotid endarterectomy in one case, left ventricular aneurysm resection in one and valvular replacement in 10 (nine aortic and one mitral replacements). The operation was elective in 42 patients (51 %) and urgent in the others. Previous myocardial infarction was found in 37 patients (45%) and left ventricular ejection fraction (LVEF) at less than 45% in 15 patients (18%); 23 patients (28%) were in NYHA class III or IV and regarding angina functional status, 77% in CCS class 3 or 4. Follow-up was complete. Statistical analysis included 30 and pre and peri-operative data. Statistical analysis used Chi-square analysis or Fisher's exact test, and the Mann-Whitney test when appropriate. The estimated probability of survival, including postoperative mortality, was calculated by the method of Kaplan-Meyer, and the Log-Rank test used to compare the results.

RESULTS

the hospital mortality was 14.6 % (n = 12). Ischemic time and ECC time were significantly lengthened in dead patients (P = 0.01). Moreover, use of internal mammary artery was directly related to lower hospital mortality (P = 0.02). For previous myocardial infarction, LVEF at less than 45%, diabetes and combined procedure, a P-value of < or = 0.1 was calculated. The follow-up ranged from 1 to 140 months (mean 36 months). There were 39 late deaths. The survival rates (included hospital mortality) were 71+/-5%, 56+/-6% and 39+/-6% at 1, 3 and 5 years, respectively. All surviving patients improved their functional status and had symptomatic relief. Statistical analysis showed significant difference in favor of long term survival for patients younger than 60 years, LVEF > 45% and NYHA class I or II.

CONCLUSION

these data confirm that CABG in patients with renal replacement therapy is associated with an high operative and long term mortality. However it allows an improvement of functional status, and so, let possible duration of dialysis. It may be expected that more active prevention and detection of coronary disease might improve these results.

Moderately hypothermic cardiopulmonary bypass and selective cerebral perfusion in ascending aorta and aortic arch surgery. Preliminary experience in twenty-two patients

Deep hypothermic cardiocirculatory arrest is the commonest method of brain protection during transverse aortic arch surgery. Its principle drawbacks consist in the limited safe ischemic period and in the coagulative, renal and pulmonary complications related to low body temperatures and prolonged cardiopulmonary bypass time. Different selective cerebral perfusion techniques have recently raised the interest of some surgical teams in an effort to obviate these problems. The authors' initial experiences with 22 patients, ranging in age from 19 to 78 years (mean, 55 +/- 15 years), who underwent ascending aorta and/or aortic arch replacement using selective cerebral perfusion and moderately hypothermic cardiopulmonary bypass are reported here. Acute aortic dissection and atherosclerotic aneurysm were the commonest lesions observed: ascending aorta associated with partial or complete arch replacement was the most widely performed procedure. With regard to the perfusion technique, after regular cardiopulmonary bypass had been established through the iliac vessels, selective cerebral perfusion was started after aortic arch vessels cannulation (innominate artery, bilateral common carotid artery, innominate artery and left common carotid artery, or right common carotid artery) using a single roller pump separately from the systemic circulation, and brain perfusion was achieved by blood cooled at 30 degrees C, at a flow rate that ranged from 300 ml/min to 1500 ml/min, at a perfusion pressure of approximately 65 mmHg, with the patient maintained at moderate hypothermia (30 degrees C rectal). To perform distal aortic repair, if transverse aortic arch or proximal descending aorta cross-clamping was not feasible, cardiopulmonary bypass flow was lowered to 300-350 ml/min and an open anastomosis was performed, while independently assuring cerebral perfusion (six patients). There were three hospital deaths (mortality rate of 13.6%; s.d. 6.0-25.5%; 70% confidence limit), but none because of cerebral accident. No paraplegia occurred. One patient suffered from right hemiparesis, neither renal nor pulmonary complications were observed. Two chest reexplorations were necessary for bleeding, which were partially related to hemocoagulative disorders. In our experience, the technique of moderately hypothermic cardiopulmonary bypass and selective cerebral perfusion in aortic surgery has provided good results with regard to cerebral protection and organ function preservation. Therefore, allowing a prolonged distal aortic reconstruction period, it may be considered as a safe alternative to profound hypothermia associated with cardiocirculatory arrest in aortic arch surgery.

Predictive factors of maximal aerobic capacity after cardiac transplantation

Exercise capacity in cardiac transplanted patients has been reported to remain decreased in some studies; however, functional results after transplantation may vary, ranging from modest to spectacular improvement. The aim of the study was to quantify exercise capacity in a large series of transplanted patients and to search for factor predictive of a good functional result. Eighty-five patients (mean 52.1 +/- 11.8 years) underwent exercise testing with respiratory gas exchange measurements 1 to 100 months after transplantation. Mean performance was 112.4 +/- 33 W with a peak VO2 of 21.1 +/- 6 ml.min-1.kg-1. Heart rate was 103 +/- 14 at rest, reaching 142 +/- 22 beats.min-1 at the end of exercising. In univariate analysis, maximal or submaximal aerobic capacity parameters were strongly correlated with chronotropic reserve (r = 0.63; P < 0.001) without correlation with cold ischaemic time, number of rejection episodes or right bundle branch block. In multiple regression analysis, chronotropic reserve, time from transplantation, age of donor and age of patient were proved to be the variables best correlated with peak VO2. Our study confirms the persistence of a large decrease in aerobic functional capacity despite cardiac transplantation; limited exercise capacity does not improve over time, and is limited not only by the patient's age but by that of the donor, and especially by chronotropic reserve.

[Alteration of myocardial viability and systemic ventricular dysfunction after Senning procedure]

After a Senning procedure for transposition of the great arteries (TGA), systolic dysfunction of the right ventricle (RV) is common. Pre and peroperative chronicale hypoxia may be the cause of this ventricular myocardial alteration. In order to detect abnormalities of myocardial viability and to study their relationship to RV function, the authors studied 41 patients (pts), 11.3 +/- 3 years after a Senning procedure. All patients underwent myocardial scintigraphy of the RV under basal conditions. 1 hour after injection of 1.5 mCi of Thallium 201. The RV ejection fraction (n = 41) and at peak effort (n = 25). Exercise ability and aerobic capacity were assessed by exercise testing (Bruce) with gas exchange measurement and compared with 41 normal matched subjects. The cardiorespiratory response to exercise was altered in the Senning group : duration of effort (10.5 +/- 2 vs 13.2 +/- 2 min; p < 0.0001), peak VO2 (33 +/- 5 vs 44.4 +/- 6 ml/min/kg; p < 0.0001), anaerobic threshold (6 +/- 1 vs 8.4 +/- 1.9 min; p < 0.05) were lower compared to controls. Abnormalities of RV viability were observed in 18/41 pts (44%), moderate in 12 cases and severe in 6 cases. Resting and exercise RVEF were significantly lower in patients with myocardial defects (45 +/- 5 vs 51 +/- 7%; p < 0.0005, and 49 +/- 9 vs 58 +/- 9%; p < 0.05 respectively). In conclusion, after the Senning procedure for TGA, scintigraphic abnormalities of the systemic ventricule are common and associated with an alteration of systolic function at rest and on exercise.

Is the Parsonnet's score a good predictive score of mortality in adult cardiac surgery: assessment by a French multicentre study

OBJECTIVE

Parsonnet proposed a preoperative score ("initial Parsonnet's score", which predicts the hospital mortality of adult cardiac surgery. This score was then modified by including several risk factors used in the 'SUMMIT' system ("modified Parsonnet's score", 44 variables). We wanted to assess the predictive value of these two scores in a French surgical population.

METHODS

From December 1992 to April 1993, in France, we organised a prospective multicentre study on adult cardiac surgery mortality and morbidity. Data on 6649 patients were included. We analysed statistically the predictive value of each risk factor and of the two scores on mortality and morbidity at one month.

RESULTS

Only 6 of the 15 variables of the initial Parsonnet's score and 19 of the 44 variables of the modified Parsonnet's score significantly influence hospital mortality. Both scores are able to predict hospital mortality and severe morbidity, but the modified Parsonnet's score has the best predictive value (initial Parsonnet's score: odds ratio by point of score = 1.01, area under the roc curve = 0.64; modified Parsonnet's score: odds ratio by point of score = 1.05, area under the roc curve = 0.70).

CONCLUSIONS

This study shows that the Parsonnet's scores are predictive, but that these scores remain imperfect: many risk factors are non significant, the initial Parsonnet's score has a moderate predictive value, and the modified Parsonnet's score is too complex (44 variables). Thus, we have built a new score for cardiac surgery in French adults.

Cardiorespiratory response to exercise after venous switch operation for transposition of the great arteries

STUDY OBJECTIVES

This study reports on the cardiorespiratory response to graded exercise in patients after venous switch operation for transposition of the great arteries.

DESIGN

Several small studies have documented a diminished exercise tolerance after Mustard repair for transposition of the great arteries, little information exists, however, about long-term cardiorespiratory exercise performance in patients who have had the Senning procedure.

PATIENTS

This prospective study reports on the serial long-term (mean, 11 +/- 2.8 years) cardiopulmonary exercise performance of 43 patients (age, 12 +/- 3.1 years) who underwent a Senning procedure, with no significant postoperative abnormalities. Forty-three matched healthy children were also studied as a control group.

MEASUREMENTS AND RESULTS

All underwent exercise testing (Bruce protocol) with metabolic gas exchange to determine parameters at 3 min, anaerobic threshold, similar heart rate (150 beats/min), and peak exercise. Time of exercise was 10.5 +/- 1.9 min in patients and 13.4 +/- 2 min in control subjects (p = 0.0001). Overall, patients reached 73% of peak oxygen uptake achieved by control subjects (32.6 +/- 5.6 vs 44.7 +/- 6 mL/kg/min). Chronotropic response (188 +/- 15.7 vs 166.5 +/- 19.6 beats/min [p = 0.0001]) and oxygen pulse (7.4 +/- 2.9 vs 10.7 +/- 4.2 mL/beat [p = 0.0002]) were lower in patients at peak exercise. Patients had a greater respiratory response to exercise: both respiratory rate and ventilatory equivalent for carbon dioxide were significantly higher at all stages of exercise. Exercise capacity assessed by peak oxygen uptake was correlated with time elapsed since surgical repair (r = 0.48; p = 0.001).

CONCLUSIONS

It is concluded that even in asymptomatic patients, exercise endurance and respiratory response are generally altered as much as 11 +/- 2.8 years after venous switch operation, although early surgical repair is predictive of a better long-term functional result.

Review of the long-term course of 52 patients with pulmonary atresia and ventricular septal defect. Anatomical and surgical considerations

This study reviews the long-term course of 52 patients with pulmonary atresia and ventricular septal defect seen in a single institution and followed for a mean period of 8.6 years (range 2 days to 20 years). Before the first operation, pulmonary blood supply was provided by ductus arteriosus supplying confluent pulmonary arteries in 26 patients (50%, group I), and was partially or entirely dependent on systemic collateral arteries in the other 26 patients (group II). The angiographic mean ratio of diameters of the right and left pulmonary artery/descending aorta (McGoon ratio) was significantly lower in group II than in group I, 0.76 +/- 0.42 vs 1.04 +/- 0.17 (P = 0.006). Severe arborization defects (with fewer than 10 pulmonary vascular segments connected to central pulmonary arteries) were present only in group II patients (eight patients: 15%), six of whom had congenital absence of the central pulmonary arteries. Corrective surgery was performed in 23 patients (44%, 14 in group I, nine in group II). All but one, who died later, had a McGoon ratio > or = 1 (mean 1.19 +/- 0.18) at time of repair. There was one hospital death (4%) and two late deaths (9%). All but one of the surviving corrected patients were in functional class I or II. Conduit replacement reoperation was performed in three patients (14%), 6, 10 and 13 years, respectively, after repair. At the end of the study, among the 37 patients (71%) who were alive (17 in group I, 20 in group II), 20 (39%) were corrected (12 in group I, eight in group II), four await corrective surgery, and six (11.5%) are estimated inoperable (all in group II) because of very hypoplastic or absent pulmonary arteries. This study confirms the estimated rate in the published literature of long-term survival in patients with pulmonary atresia and ventricular septal defect, and the good results of corrective surgery whenever the size and distribution of pulmonary arteries are satisfactory. The problem of very hypoplastic pulmonary arteries and severe arborization defects remains contentious.

[Cerebral protection by selective cerebral perfusion during surgery on the aortic arch]

The aim of this study was to evaluate the technique of cerebral protection by selective cerebral perfusion with moderate hypothermia during surgery of the transverse aortic arch. Twenty-three patients were operated for partial or total replacement of the transverse aortic arch between January 1987 and December 1993 by the technique of selective cerebral perfusion by bilateral carotid cannulation. There were 12 cases of aneurysm of the ascending aorta and/or transverse aortic arch, one aneurysm of the innominate artery and 10 Stanford type A aortic dissections. The selective cerebral flow rate was 1-1.5 l/min; the perfusion pressure 60-80 mmHg and the temperature of cerebral perfusion 25-28 degrees C. The perioperative mortality was 13%; the causes of death were not neurological (3 haemorrhages). The neurological morbidity was 10% (one brachial monoparesis and one bulbar tetraparesis). This is therefore a useful technique of cerebral protection which avoids the complications of deep hypothermia with circulatory arrest and does not limit the time of aortic repair.

A 8-year follow-up of the Edwards-Duromedics bileaflet prosthesis

Following reports of leaflet escapes, distribution of the Edwards-Duromedics prosthesis (ED), introduced in 1982, was suspended from 1988 to 1990. From our experience of 257 patients operated on between March, 1983, and April, 1988, it appeared to us that, among the five key factors identified by extensive studies, surgical mishandling, specially in mitral position, could have been the main contributing factor. These 257 patients, mean age 57 years (range 2 to 75 years), underwent 138 aortic (AVR), 86 mitral (MVR), and 33 double valve (DVR) replacements. Hospital mortality was 2.3% (6 patients): 1.4% for AVR, 3.5% for MVR, and 3% for DVR, none of them being directly valve-related. But there were 3 early replacements of a mitral ED for intra or postoperative impingement of one leaflet. Follow-up has been 93%, with a total of 1.155 patient-years. Among the 20 late deaths (8%), 4 (20%) were considered as valve-related; there was one MV thrombosis and 7 non-fatal systemic emboli, the total incidence of thromboembolism being 0.7% patient-year. No structural failure or leaflet escape was observed in this series. At 8 years, actuarial survival, hospital mortality excluded, was 85.5% for AVR, 95% for MVR, and 89% for DVR. The ED prosthesis is, from a hydrodynamic point of view, an advance in terms of both mechanical and bileaflet valve: the valve design accounts for its low thrombogenicity. But its persistent drawback remains the prohibitive vertical exposure of leaflets in mitral position, that can be responsible for immediate or delayed leaflet entrapment, or for incautious handling for rotating the mechanism, leading to extensive fissuration of pyrolitic carbon and delayed rupture. (ABSTRACT TRUNCATED AT 250 WORDS)

[Complications of endocardial biopsy in heart transplant patients]

Despite the increasing use of alternative techniques, endomyocardial biopsy remains the primary method for diagnosing cardiac allograft rejection. Between March 1986 and May 1994, 2,894 endomyocardial biopsies performed on 183 heart transplant patients were reviewed. A total of 53 (1.8%) complications occurred. 33 (1.1%) complications were associated with the introduction, including carotid puncture (0.9%), neurological reaction (0.1%), and pneumothorax (0.1%). Complications during biopsy included arrhythmias (0.4%) and ventricular perforation (0.2%). In addition, we observed three episodes of allergic reaction to a reusable biotome, three episodes of liver biopsy, and one case of pacemaker dislodgement. All complications were without significant long-term sequelae. In contrast to the cardiomyopathy population, no severe ventricular perforations or deaths occurred. Thus although endomyocardial biopsy has some risk, it continues to be a safe and effective way of monitoring rejection.

[Comparative value of transthoracic echocardiography and angiography for measuring the pulmonary artery annulus in tetralogy of Fallot]

It may be necessary to perform an enlarging pulmonary annuloplasty during surgical cure of Tetralogy of Fallot (TOF) in order to optimise reconstruction of the right ventricular outflow tract. As this additional procedure implies an increase in perioperative mortality, it is useful to prepare for this eventuality before surgery. Two imaging techniques are available: transthoracic echocardiography (diameter of the pulmonary annulus obtained by averaging the measurements obtained in the subcostal and parasternal short axis views of the insertion of the pulmonary valve cusps at end systole) and selective angiography during right heart catheterisation (anteroposterior measurement with comparison to be projected and real size of the catheter at the point of insertion of the cusps at end systole). In this study, these two techniques were compared with reference to the peroperative measurement with Hegar dilators and criteria defined by Naito (minimal diameter of the pulmonary artery annulus with respect to the weight of the child). Seventy-eight children admitted to hospital between January 1986 and April 1994 for curative surgery of TOF were included. The calculation of the intra-class correlation coefficient showed a mediocre correlation with angiography and a very mediocre correlation with echocardiography compared with peroperative measurements. However, the calculation of sensitivities showed angiography to be the predictive investigation for annuloplasty in children not conforming to the Naito criteria: higher sensitivity (83% vs 26% for echocardiography), greater negative predictive value (84% vs 70%). This result holds for all categories of body weight (over and under 10 kg).(ABSTRACT TRUNCATED AT 250 WORDS)

Quality of care in adult heart surgery: proposal for a self-assessment approach based on a French multicenter study

A prospective study was carried out from January to April 1993 in 42 centers to assess the quality of care in adult heart surgery in France. One hundred eight parameters were collected (i.e., risk factors, surgery, postoperative course) for 7181 patients. Eight simple, objective factors were selected using a multivariate analysis. Point weighting was assigned to each factor. A simple cumulative score was thereby established to classify patients within four incremental risk groups (respective distribution of patients and mortality were 38.6%, 26.5%, 21.3%, 13.5% and 2%, 3.9%, 6.1%, 21.4%). This score was highly predictive for mortality and severe morbidity. Objectivity and independence of the observer, coupled with a reliable score, are needed for meaningful assessment of the quality of care. Administrative supervision and/or comparison of raw center results therefore remain controversial. A national data base was developed as a part of this study, that includes anonymous information from two-thirds of all cardiac surgery cases. Nation-wide results for France allow each center freely to assess its results. This self-assessment approach is, in our view, the most accurate way of quality of care assessment. A pan-European system using a similar approach should be developed.

Surgical experience of coronary artery-right ventricular fistula in a heart transplant patient

Routine follow-up catheterization 4 years after heart transplantation in a 55-year-old revealed a fistula from the main left anterior descending artery (LAD) to the right ventricle. The left anterior descending artery was dilated and tortuous because of this fistula. As he had effort dyspnea and fatigue 3 months after this catheterization, we decided to operate on the fistula, and direct closure of this through the LAD and coronary artery bypass grafting from the proximal to distal LAD were performed. Surgery and the postoperative course were uneventful. We discuss the surgical indication and technique for coronary artery fistula acquired as a result of endomyocardial biopsy after heart transplantation.

Mechanical cardiac valve thrombosis. Is fibrinolysis justified?

BACKGROUND

Thrombosis is a serious complication of heart valve replacement, and management is often difficult. In recent years, thrombolytic therapy has been used as the primary technique by some investigators.

METHODS AND RESULTS

Sixty-four consecutive patients presenting with 75 instances of prosthetic heart valve thrombosis (41 mitral, 33 aortic, one tricuspid) were treated with fibrinolytic agents. Obstructed prosthetic valves comprised 39 tilting disc and 36 bileaflet valves. The time interval between valve replacement and obstruction ranged from 15 days to 192 months (mean, 38 months). Fibrinolytic agents used were streptokinase (42 patients), urokinase (27 patients), or recombinant tissue-type plasminogen activator (six patients). Immediate results of fibrinolytic treatment were 1) full success after one or several consecutive fibrinolytic regimens in 55 cases (73%), 2) incomplete improvement in two cases, and 3) failure in 18 cases, leading to an emergency surgery in nine cases. Nine patients died (four strokes, four cardiac arrests, one hemorrhage). Only one severe hemorrhagic complication was observed, but 11 cases of embolism occurred during fibrinolytic treatment (14.6%) (four major cerebral embolisms with death). The immediate efficacy was better for thrombosed aortic prosthesis than with the mitral prosthesis (85% versus 63%).

CONCLUSIONS

Fibrinolytic treatment appears to be an attractive nonsurgical alternative for prosthetic heart valve thrombosis, but because of the risk of cerebral embolism, its use should be reserved for tricuspid valve thrombosis or critically ill patients with mitral or aortic valve thrombosis. The use of a fibrinolytic agent in cases of small, nonobstructive paravalvular thrombosis demonstrated with transesophageal echocardiography needs further studies.

Isolation of the right subclavian artery

Loss of continuity between subclavian artery and aorta with persistent connection to the homolateral pulmonary artery through a ductus arteriosus is an uncommon malformation, involving generally the left subclavian artery and associated with intracardiac or aortic arch anomalies. We report a case of right subclavian isolation with a left-sided aortic arch, presenting as a single anomaly and surgically corrected by aortic reimplantation.

Bronchial revascularization in double-lung transplantation: a series of 8 patients. Bordeaux Lung and Heart-Lung Transplant Group

Donor airway ischemia is the main cause for defective tracheal or bronchial healing after double-lung transplantation. Anatomical studies and bronchial arteriograms have shown that the right intercostal bronchial artery is constant (95% of instances) and provides an important blood supply to the distal trachea, the carina, and the right bronchial tree as well as to the left side through a subcarinal and periadventitial anastomostic network. To maintain this important bilateral bronchial circulation, it is of capital importance not to mobilize the arteries individually and to avoid large dissections around the carina. Both bronchi can thus be revascularized by indirect aortic reimplantation using a bypass graft to a single aortic patch that includes the origin of the right intercostal bronchial artery. Furthermore, the origin of other vessels (a common trunk and left arteries) can be found within a short distance of the right intercostal bronchial artery and possibly be contained within the same aortic patch. From a series of 56 lung transplantations, 8 patients underwent restoration of the bronchial vascularization using a recipient saphenous vein graft between the donor bronchial arteries and the anterior aspect of the recipient's ascending aorta. A lower tracheal anastomosis was performed. Bronchial arterial blood supply was evaluated both by endoscopy and by arteriography at about the 15th postoperative day. The bronchial circulation was visualized at this time in five of seven arteriographies, and this was associated with excellent tracheal healing in all 8 patients.

Lung transplantation with bronchial revascularisation. Surgical anatomy, operative technique and early results

Ischaemic anastomotic complications are an important cause of mortality and morbidity after lung transplantation. Anatomical studies have demonstrated that the pattern of bronchial arterial supply is relatively constant and therefore amenable to attempts at revascularisation. From May 1990, 10 patients who had a double lung transplantation (tracheal anastomosis) and 1 patient who had a right lung transplantation underwent concomitant bronchial revascularisation. There were two early and one late deaths. There were no anastomotic complications. Regular endoscopic examination showed satisfactory healing in all patients. Early angiography showed patent grafts in 7 of 9 patients. At a mean follow-up of 11 months (range 6-17 months) 8 patients are well and leading a normal life. This report describes the anatomical basis, technical aspects and early results of a promising operative procedure in the field of lung transplantation.

[Leiomyosarcoma of the right ventricle. Report of a case and review of the literature]

Primary cardiac leiomyosarcoma is a very rare condition. Only 15 cases have been reported in the literature. We report the case of a 27 year old man admitted to hospital for chest pain in March 1985. Echocardiography showed a right ventricular tumour which was completely resected at surgery. The diagnosis of leiomyosarcoma was confirmed by histological examination. After 22 months follow-up, the patient was still alive despite pulmonary metastases. The diagnosis of cardiac tumour used to be made post-mortem but since the introduction of new methods of investigation, especially 2D echocardiography, the diagnosis can be made at an early stage and allows rapid surgical resection, the only means of obtaining the histological diagnosis and of completely curing benign tumours.

[Total anomalous infra-cardiac pulmonary venous connection. Value of the color Doppler echocardiography]

A case of total anomalous pulmonary venous connection is described in a newborn. The pulmonary veins join a common trunk entering portal vein below the diaphragm. The pattern of pulmonary venous connections was identified by two-dimensional Doppler color flow-mapping echocardiography. The common pulmonary venous trunk was anastomosed to the left atrium at the age of 3 weeks but the infant died because of pulmonary hypertension and acute renal insufficiency. The Doppler color echocardiography allows a good preoperative evaluation. The spontaneous prognosis being poor, surgical correction is indicated and should be performed early, even for critically ill neonates. Patients who survive to childhood lead active and full lives.

[Value of Naito's criteria in the surgical repair of tetralogy of Fallot]

Naito suggested criteria for the optimal reconstruction of the right ventricular outflow tract in total correction of tetralogy of Fallot based on the minimum acceptable diameter of the pulmonary artery. The value of these criteria was assessed in 78 operated patients by haemodynamic measurements at surgery and 6 months after operation. Using these criteria, a ratio of right ventricular/left ventricular systolic pressure less than 0.60 was obtained with the creation of pulmonary regurgitation which was usually moderate. Long-term assessment of these results is required.

Lung and heart-lung transplantation for end-stage lung disease. The Bordeaux Lung and Heart-Lung Transplant Group

Between February 1988 and December 1989, 15 combined heart-lung, 2 double lung and 5 single lung transplants were performed at our institution for end stage lung disease. The indication for heart-lung transplantation was primary lung disease with associated secondary heart failure in 11 cases, diffuse pulmonary disease with extensive adenopathy of the hilum in 2 cases and profuse and antibiotic-resistant tracheobronchial infection due to Pseudomonas in 2 cases. A double lung transplant was performed in 2 patients with hypertensive emphysema. The indication for a single lung transplantation was emphysema in 2 cases and pulmonary fibrosis in 3 cases; in this last indication, transplantation should be performed on the right side with a slight lengthening of the main bronchus to avoid the side-effects of mediastinal shift. There were 2 early deaths, 7 secondary deaths (from the 2nd to the 5th month) due to viral or bacterial infectious complications, and 1 late death in the 7th month (infection due to a syncitial virus). All 12 surviving patients have an excellent functional result; the size of the tracheal or bronchial anastomosis ranges from 85% to 100% of normal. From this experience, we conclude that specificity and severity of lung hazards are mainly related to bronchial infection, dependence on steroids and pleural adhesions. Moreover, posttransplant pulmonary oedema, mucociliary dysfunction and the differential diagnosis between rejection and infection require careful endobronchial suction and periodical sampling.

[Low molecular weight heparin: an real alternative in thrombolysis in hemodialyzed patients. A trial of coronary thrombolysis]

Fibrinolytic treatments pose serious problems in subjects at high risk for hemorrhage, such as those requiring chronic dialysis. A 36-year-old patient requiring dialysis for the last 14 years due to chronic kidney failure was hospitalized for unstable angina combined with calcified mitral stricture. Prompt coronary arteriography revealed recent intracoronary thrombi. The failure of drug treatment and the surgical indication in light of unstable angina led the authors to use low-molecular-weight heparin b.i.d. for 12 days with monitoring of laboratory parameters (anti-Xa activity, APTT). No thrombotic or hemorrhagic episode was recorded. Control angiography indicating partial lysis of the left and right intracoronary thrombi led to exact evaluation of the residual underlying stenoses. A double aortocoronary bypass was subsequently performed combined with replacement of the mitral valve. This case gives a glimpse of the potential value of low-molecular-weight heparin as a valid alternative to conventional fibrinolysis in subjects requiring dialysis.

Aneurysms of the abdominal aorta in the neonate and infant

We report a case of aneurysm of the infrarenal abdominal aorta from septic umbilical artery catheterization in a one-month old female infant. In spite of spontaneous thrombosis, the patient's course was uneventful. During the five-year follow-up period no further complications developed and operation was not required. Aneurysms of the aorta are rare in the very young and the infrarenal location is rarer. Sixteen other cases published in the literature are reviewed. Etiologic considerations and therapeutic modalities are discussed.

Ultrastructural study comparing the myocardial protective effects of four different infusates (Bretschneider's, St Thomas's, standard Ringer's and blood potassium solutions) in the human heart

Comparative mitochondrial ultrastructural changes during myocardial ischaemic periods have been assessed when using four different solutions: Bretschneider's solution (BS) (K+ = 10 mEq/l) at 4°C; St Thomas's hospital solution (STS) (K+ = 20 mEq/l) at 4°C; standard Ringer's solution (SRS) (K+ = 2.7 mEq/l) at 4°C; blood potassium cardioplegic solution (BPS) (K+ = 21 mEq/l) at 15°C.

BS (n = 8), STS (n = 10), SRS (n = 8) and BPS (n = 8) were infused in 34 patients undergoing aortic valve replacement (n = 17) or aortocoronary bypass grafting (n = 17), after aortic crossclamping, either in the aorta or in both coronary ostia, until the septal myocardial temperature reached 10-13°C for crystalloid solutions or 15°C for blood cardioplegia. Myocardial biopsies were taken from the left ventricular apex, on a beating heart, at the beginning and end of bypass.

To assess the degree of ischaemic injury, an ultrastructural evaluation of the mitochondria was done and four histological classes have been defined: class I- dense matrix and cristae; class II — occasional mitochondrial swelling; class III — decrease in matrix density with extensive swelling; class IV — severe swelling and/or rupture of matrix.

This study showed that: (1) only the St Thomas's and Bretschneider's solutions provide a rapid electromechanical asystole; (2) isolated hypothermic crystalloid solution with low potassium concentration (standard Ringer) is not sufficient either to induce cardiac arrest or to prevent detrimental mitochondrial changes; (3) Bretschneider's solution appears to provide the best ultrastructural mitochondrial preservation during myocardial ischaemia.

Risk factors for myocardial infarction during coronary artery bypass graft surgery

Patients with a particular thrombotic profile may be at greater risk of myocardial infarction during coronary artery bypass graft surgery. The thrombotic profile of 50 patients admitted to hospital with stable angina pectoris was determined prior to haemodynamic investigation. ECG results and determination of cardiac enzymes showed that 12 patients had suffered a perioperative myocardial infarction. These patients had a higher mean atherosclerotic score (42.1 +/- 10.5 vs 32.9 +/- 13, P less than 0.02), a longer aortic cross clamp time (59 +/- 15.2 vs 45.7 +/- 16.3 min, P less than 0.05), lower serum levels of protein C (101.2 +/- 26 vs 124.7 +/- 31.4%, P less than 0.05) and tissue plasminogen activator (322 +/- 580 vs 2307 +/- 2830 IU ml-1, P less than 0.01). There were no differences between the two groups in Jenkin's coronary score, the number and type of grafts, ejection fraction, left ventricular end-diastolic pressure, lipid profile or levels of markers of platelet release. In addition to a more severe distal coronary atheroma and a longer aortic cross-clamp time, patients with impaired endothelial fibrinolytic activity appeared to be at greater risk of myocardial infarction during coronary artery bypass graft surgery.

Late results of the subclavian flap repair of coarctation in infancy

From June 1979 through January 1985, 22 infants under 20 months of age (mean 8 months and 4 kg) underwent coarctation repair with a left subclavian aortoplasty. The most commonly associated lesions were ventricular septal defect (50%), hypoplastic aortic arch (45%), patent ductus arteriosus (41%), transposition of great arteries (22.7%) and other intracardiac lesions comprised 30%. Indication for surgery was congestive heart failure refractory to medical management. All patients were on inotropic support. Two patients required mechanical ventilation preoperatively. Subclavian flap angioplasty was performed with 7.0 continuous polypropylene suture. Ligation of a patent ductus arteriosus was simultaneously done in 8 patients and pulmonary artery banding in 8 others. Four patients (18%) died within 30 days after operation; 3 of them had severe tubular hypoplasia of the aortic arch. Three transient postoperative complications were encountered; chylothorax, subclavian steal syndrome and Horner's syndrome. No hospital deaths occurred in patients with isolated coarctation of the aorta. All survivors were followed for a period varying from 3 to 6.5 years (mean, 2 years). There were 3 late deaths (13.6%). Non invasive studies have shown a satisfactory result in 14 patients with a residual gradient less than 20 mmHg and in 10 of them, cardiac catheterization and cineangiography showed no evidence of significant stenosis. In one patient only, femoral pulses were absent 4 months postoperatively. These results and reports of others indicate, contrary to the age, that the presence of associated disease affects mortality. Prompt repair of coarctation of the aorta in all infants with or without symptoms is recommended and the subclavian flap procedure appears to be a simple and safe method for relief of coarctation of the aorta in critically ill infants.

Traumatic rupture and aneurysm of the aortic isthmus: late results of repair by direct suture

Between 1979 and 1986, 28 patients underwent surgery for subadventitial rupture of the aortic isthmus from blunt trauma; 16 had an acute lesion which was operated within three days after the trauma, three had a delayed repair between the first and third months, while nine had a chronic post-traumatic aneurysm (2 to 27 years after the initial accident). Transection was complete in 13 cases. A left atrium-to-descending thoracic aortic bypass or ilioiliac extracorporeal bypass were used in 14 (50%) patients whereas simple clamping was employed in the 14 remaining patients. Aortic repair was performed in 22 cases by direct suture (78.5%), more often in acute ruptures (84%) than in chronic aneurysms (66%). Five of the 16 patients operated on within three days of their accident died during the first postoperative month from associated lesions. There were no in-hospital or late deaths among the patients operated on for chronic aneurysm. All of the 23 surviving patients (82%) were followed postoperatively for six to 90 months (mean: 36 months). Of the 19 who had direct suture, 15 underwent digital subtraction arteriography which demonstrated an excellent reconstruction of the aortic isthmus. Of the techniques available for repair of traumatic aortic lesions, direct suture allows the shortest clamping time (mean: 25 minutes in our series). The long-term risks of prosthetic replacement, i.e. late infection, false aneurysm due to suture breakdown, and secondary embolism arising from mural thrombosis, can therefore be avoided.

Magnetic resonance imaging of an anomalous origin of the left coronary artery from the pulmonary artery

This report describes a 34-year-old woman with an anomalous origin of the left coronary artery from the pulmonary artery. The angiographic pattern was clearly demonstrated by magnetic resonance imaging (MRI) performed before surgery. This case suggests that MRI could play an important role in the pre-operative assessment of coronary anomalies.

Accuracy of M-mode and two-dimensional echocardiography in the diagnosis of aortic dissection: an experience with 128 cases

The accuracy of combined M-mode and two-dimensional echocardiography in the diagnosis of aortic dissection was evaluated in 673 patients with a clinical suspicion of aortic dissection, over a six-year period. In 128 cases, the diagnosis of aortic dissection was confirmed by angiographic, tomographic (CT scan), or autopsy findings, or during surgery. Two echocardiographic features were found to support a diagnosis of aortic dissection: a dilation of at least one segment of the aorta (sensitivity 95%, specificity 51%) and a typical abnormal linear intraluminal echo corresponding to the intimal flap (sensitivity 67%, specificity 100%). This pathognomonic intimal flap was observed in 86 cases, of which three types could be distinguished: (1) a long oscillating flap (n = 15), (2) a long but minimally mobile linear echo which was duplicated and parallel to one or two aortic walls (n = 64), (3) a short, double linear image with a rapid systolic motion and high frequency oscillations. These features were found to have a high sensitivity in type I aortic dissection (88%), although in types II and III the sensitivity was much lower. In some cases, a fourth type of abnormal image could be detected: a small intraluminal echo moving in parallel to the aortic wall. This feature should be interpreted with caution since its predictive value for a positive examination was low (48%). Out of 23 cases in which the diagnosis of aortic dissection was suspected on the basis of this doubtful abnormal echo, it was confirmed in only 11 patients. The results in these 128 cases of aortic dissection indicate that two-dimensional echocardiography, which is easily performed at the patient's bedside, could take priority in investigations of this condition. It is extremely sensitive in the diagnosis of ascending aortic dissection, but much less so in the diagnosis of descending aortic dissection.