Ten-year results of aortic valve replacement with first-generation Mitroflow bioprosthesis: is early degeneration a structural or a technical issue?

OBJECTIVES

Concerns have been raised about the durability of the first-generation Mitroflow aortic bioprosthesis (model 12 A-LX) due to the lack of anticalcification treatment. This study reflects a 10-year experience with this prosthesis for aortic valve replacement.

METHODS

From June 2003 to May 2012, the Mitroflow prosthesis was used for aortic valve replacement in 510 patients, of whom only 467 with complete clinical follow-up were included for analysis. Study end-points were survival and incidence of structural valve degeneration (SVD). Analysis of SVD was based on cumulative incidence function and competing-risk Cox regression.

RESULTS

The mean patient age was 76.4 ± 6.1 years. Valve sizes from 23 to 25 were used in 70.4%, whereas sizes from 19 to 21 were used in only 19.2%, thereby avoiding patient-prosthesis mismatch in 89.1%. Within a median follow-up time of 6.6 years (interquartile range 4.4), a cumulative 2375 patient-years, the survival rate was 86.2%, 67.3% and 33.3% at 1, 5 and 10 years, respectively. The cumulative incidence of SVD, with death as a competing risk, was 0%, 0.7% and 6.2% at 1, 5 and 10 years, respectively. Only age <75 years tended to affect the late hazard of SVD (hazard ratio 0.50, 95% confidence interval 0.23-1.08, P  = 0.08), regardless of valve-specific issues.

CONCLUSIONS

The data do not support the concerns about early accelerated structural degeneration of the first-generation Mitroflow bioprosthesis used for aortic valve replacement in patients older than 75 years. We postulate that limiting the number of small prostheses using a proper implantation technique has enhanced the reduction in risk of significant patient-prosthesis mismatch as the main determinant of early SVD.

Minimally Invasive Repair of Mitral Valve Prolapse and Concomitant Atrial Fibrillation Ablation in a Heart Transplant

Significant mitral valve disease with atrial fibrillation after heart transplantation is unusual. We report the diagnosis and minimally invasive surgical treatment 17 years after transplantation, in which mitral valve repair together with left atrial ablation was performed, resulting in a satisfying clinical and echocardiographic improvement.

Aortic Valve Replacement with Toronto SPV in Elderly Patients: 10-Year Results

A retrospective assessment of clinical and echocardiographic variables was performed in 145 patients who received a Toronto SPV aortic valve replacement. The majority (90%) of these elderly patients (mean age, 75.5 ± 7.4 years) were preoperatively in New York Heart Association class III–IV. Operative mortality was 4.8%. Follow-up was complete up to 10 years and revealed few valve-related complications: thromboembolism (7), bleeding (4), and prosthesis dysfunction necessitating reoperation (3). Late mortality was cardiac-related in 11.7% and noncardiac-related in 17.2%. Actuarial survival was 83% at 5 years and 63% at 8 years. Echocardiography showed low transvalvular gradients (peak, 17.5 ± 7.5 mm Hg; mean, 9.2 ± 4.2 mm Hg) resulting in a significant reduction in left ventricular mass index during the first 3 years. Independent of the transprosthetic gradient, left ventricular mass index tended to increase again beyond the 5th year, which correlated positively with the presence of arterial hypertension in this older population. The Toronto SPV bioprosthesis offers an aortic valve substitute with excellent long-term hemodynamics, resulting in significant early left ventricular mass regression. Considering the limitations of this selected elderly population, the clinical outcome and survival up to 10 years are encouraging, with few observed valve-related events.

Reappraisal of a single-centre policy on the contemporary surgical management of active infective endocarditis

OBJECTIVES

We studied a contemporary cohort of adult patients treated surgically for infective endocarditis (IE) in order to evaluate the surgical approach and predictors of outcomes, in relation to the intercurrent adaptation of the 2006 ACC/AHA guidelines.

METHODS

One hundred and eighty-six consecutive patients operated on for active IE from August 1999 to September 2012 were reviewed retrospectively. Clinical presentation, surgical management and outcomes in the two study periods before and after January 2007 were compared (Period 1: n = 95 and Period 2: n = 91).

RESULTS

The mean (SD) follow-up was 4.3 (3.8) years and was 99.5% complete. Patients in Period 2 had more frequently associated coronary artery disease (31 vs 18%, P = 0.06), while the microbiology revealed more Staphylococcus species (43 vs 26%, P = 0.02), predominantly Staphylococcus aureus (31 vs 19%; P = 0.07), and less culture-negative cases (7 vs 17%; P = 0.05). The median delay between diagnosis and surgery was 7 days in Period 2 compared with 14 days in Period 1 (P = 0.001). Surgery in Period 2 included more root replacements for aortic valve endocarditis (11 vs 2%; P = 0.02) and mitral valve repairs (18 vs 5%; P = 0.01), while the use of homografts for aortic valve endocarditis was almost abandoned (1 vs 15%; P = 0.001). Hospital mortality was 13% and did not change significantly over both periods (P = 0.66). The independent predictors of hospital mortality were age (P = 0.03), female gender (P = 0.02), previous cardiac surgery (P = 0.02), preoperative serum creatinine level >2 mg/dl (P = 0.05), S. aureus infection (P = 0.02), emergent or salvage operation (P = 0.001) and concomitant coronary artery bypass grafting (P = 0.03). The 1-, 3-, 5- and 10-year survival were 84, 72, 64 and 57%, respectively. Late survival was negatively influenced by S. aureus endocarditis (P < 0.001) and peripheral vascular disease (P = 0.03), whereas associated coronary artery disease (P = 0.07) had a strong impact.

CONCLUSIONS

Adaptation of the 2006 ACC/AHA guidelines in the contemporary management of IE led to a shorter interval between diagnosis and surgery. Despite a more extensive and earlier operative approach, IE caused by S. aureus still remains a major determinant of early and late outcomes.

Fatal acute pulmonary injury associated with everolimus

OBJECTIVE

To report a case of fatal alveolar hemorrhage associated with the use of everolimus in a patient who underwent a solid organ transplant.

CASE SUMMARY

In a 71-year-old cardiac transplant patient, cyclosporine was replaced with everolimus because of worsening renal function. Over the following weeks, the patient developed nonproductive cough and increasing dyspnea. His condition deteriorated to acute respiratory failure with hemoptysis, requiring hospital admission. Bilateral patchy alveolar infiltrates were apparent on chest X-ray and computed tomography. Cardiac failure was ruled out and empiric antimicrobial therapy was initiated. Additional extensive workup could not document opportunistic infection. Everolimus was discontinued and high-dose corticosteroid therapy was initiated. Despite this, the patient required invasive mechanical ventilation and died because of refractory massive hemoptysis. Autopsy revealed diffuse alveolar hemorrhage.

DISCUSSION

Everolimus is a mammalian target of rapamycin inhibitor approved for use as an immunosuppressant and antineoplastic agent. Its main advantage over calcineurin inhibitors (tacrolimus and cyclosporine) is a distinct safety profile. Although it has become clear that everolimus induces pulmonary toxicity more frequently than initially thought, most published cases thus far represented mild and reversible disease, and none was fatal. Here, we report a case of pulmonary toxicity developing over weeks following the introduction of everolimus, in which a fatal outcome could not be prevented by drug withdrawal and corticosteroid treatment. The association of everolimus and this syndrome was probable according to the Naranjo probability scale.

CONCLUSIONS

This case indicates that with the increasing use of everolimus, clinicians should be aware of the rare, but life-threatening manifestation of pulmonary toxicity.

Twenty years' single-center experience with mechanical heart valves: a critical review of anticoagulation policy

BACKGROUND AND AIM OF THE STUDY

Since January 1990, a variety of mechanical valves (St. Jude Medical, CarboMedics, ATS Medical) have been implanted routinely at the authors' institution. The study aim was to analyze, retrospectively, the 20-year clinical results of those mechanical valves, and to challenge the anticoagulation policy employed over the years.

METHODS

Between January 1990 and December 2008, a total of 2,108 mechanical valves was inserted into 1,887 consecutive patients (1,346 aortic, 725 mitral, 27 tricuspid, 10 pulmonary). The mean age of the patients was 63 +/- 13.2 years, and the majority (61%) were males. Preoperatively, 71% the patients were in NYHA class > or = III (average 3.01). The most frequent comorbidities included: atrial fibrillation (n = 594), coronary disease (n = 567) and diabetes (n = 398). The follow up (99% complete) totaled 13,721 patient-years (pt-yr), and ranged from 12 to 241 months (average 84 months).

RESULTS

In-hospital mortality was 5.2% (n = 98, 14 valve-related). Of the 629 late deaths, the majority were cardiac (n = 276). Survival (Kaplan-Meier estimation) was significantly better for aortic valve patients compared to mitral or multiple valve replacement (Mantel-Cox, p < 0.0001). The overall linearized incidences (as %/pt-yr) were: valve thrombosis 0.31, thromboembolism 1.08, and bleeding 0.91. However, as repeated events occurred in several patients, the hazard function was not constant. Multivariate analysis (Cox regression model) showed age > 70 years (p < 0.0001), NYHA class > or = III (p < 0.0001), non-sinus rhythm (p = 0.001), concomitant coronary artery bypass grafting (p = 0.008) and higher International Normalized Ratio (INR) values (p = 0.013) as significant risk factors for death, with a trend for redo operations (p = 0.052). Multivariate analysis found variable INR, non-sinus rhythm and NYHA class > II as significant risk factors for thromboembolism, while long-acting coumadin and NYHA class > II were significant risk factors for bleeding.

CONCLUSION

This 20-year experience demonstrated excellent clinical outcomes for patients with mechanical prostheses, with no valve structural failure and an acceptable incidence of adverse events. INR values between 2-2.5 for aortic valve patients, and 3-3.5 for mitral valve patients, yielded the fewest major adverse events.

Ten years single-centre experience with intra-aortic balloon pump

OBJECTIVES

The objective of this study was to investigate the patient characteristics and outcomes in 1406 patients undergoing intra-aortic balloon pump (IABP) counterpulsation.

METHODS

Between 1998 and 2008, 1406 consecutive patients were recorded in a prospective database. Based on the main clinical indication for IABP use, we defined 3 groups: group A, 630 cases of coronary ischaemia or infarction without serious left ventricular (LV) dysfunction; group B, 466 patients with left ventricular failure or cardiogenic shock; group C, 310 patients where IABP was used for miscellaneous procedures such as weaning from cardiopulmonary bypass or during high-risk angioplasty or surgery.

RESULTS

Global mortality was 28% (n = 390), with a significant difference between group A (15%, n = 95) and group B (41%, n = 191) (P < 0.001). Mortality in group C was 34% (n = 104). Most insertions were done in the catheterization laboratory (n = 943) with subsequent mortality of 23% whereas 199 balloons were inserted in the operation room with 34% mortality. 170 balloons inserted in the intensive care unit resulted in 46% mortality (P < 0.001). Major IABP-induced complications were 6.8% with no statistical differences between the three groups. Advanced age, left ventricular failure and low BMI were identified as prognostic risk factors for early mortality.

CONCLUSIONS

IABP deployed at an early clinical stage yields the best results, especially for acute coronary patients with preserved LV function whereas LV failure and late insertion result in worse outcome.

Fifteen years' single-center experience with the ATS bileaflet valve

BACKGROUND AND AIM OF THE STUDY

Since its introduction in May 1992, the bileaflet ATS Open Pivot valve has been implanted routinely at the authors' institution. The study aim was to analyze, retrospectively, the 15-year clinical results of these implanted ATS valves.

METHODS

Between May 1992 and December 2005, a total of 1,160 ATS valves (749 aortic, 381 mitral, 21 tricuspid, nine pulmonary) was implanted in 1,047 consecutive patients (655 males, 392 females; mean age 62.1 +/- 12.4 years). Preoperatively, 75% of the patients were in NYHA class III or higher (mean 3.1). The most frequent comorbidities included atrial fibrillation (n = 381), coronary disease (n = 288) and diabetes (n = 172).

RESULTS

The mean follow up was 78 months (range: 24-183 months); the total follow up was 6,887 patient-years (pt-yr) and was 99.8% complete. In-hospital mortality was 4% (n = 43; three valve-related). Survival (Kaplan-Meier) at five and 10 years was significantly better for aortic than for mitral valve patients (84% and 65% versus 75% and 41%, respectively) (Mantel-Cox, p < 0.001). A log rank analysis detected no statistical difference in the incidence of thromboembolism (p = 0.182) or bleeding (p = 0.375) between both groups. The overall linearized incidences were: thromboembolism 1.08%/pt-yr; bleeding 0.91%/pt-yr; endocarditis 0.22%/pt-yr; paravalvular leakage 0.33%/pt-yr; and valve thrombosis 0.21%/pt-yr. Multivariate analysis (Cox regression) indicated age > 70 years (p < 0.0001), NYHA class > or = III (p < 0.0001), non-sinus rhythm (p = 0.001), concomitant CABG (p = 0.008) and higher INR values (p = 0.013) to be significant risk factors for death.

CONCLUSION

This 15-year experience with the ATS bileaflet prosthesis showed excellent clinical outcomes for patients, with no structural failure and an acceptable incidence of adverse events.

Short-term systolic and diastolic ventricular performance after surgical ventricular restoration for dilated ischemic cardiomyopathy

OBJECTIVE

Based on the adverse relationship between left ventricular (LV) remodeling and clinical outcome in ischemic cardiomyopathy, surgical ventricular restoration (SVR) is proposed as a valuable adjunct procedure. This study reports on the short-term clinical and hemodynamical performance of SVR.

METHODS

Using end-systolic LV volume as indication for SVR, 78 patients with ischemic cardiomyopathy are divided in two groups: group 1 comprised 55 patients treated by coronary revascularization and mitral annuloplasty, group 2 comprised 23 patients undergoing additional SVR. Hemodynamic investigation included echocardiographic assessment of systolic and diastolic function. Clinical follow-up focused on survival and functional status with exercise performance.

RESULTS

Both surgical approaches resulted in improvement of NYHA class (2.9-1.6 in group 1; 3.3-1.5 in group 2, p<0.001), achieving similar exercise performance (peak VO2 13.7 vs 15.4 ml/kgmin in groups 1 and 2, p=0.25) and plasma BNP values (group 1: 1350 pg/ml and group 2: 767 pg/ml, p=0.23). SVR provided additional benefit as patients basically had a worse NYHA class (2.9 in group 1 vs 3.3 in group 2, p=0.03). Within mean follow-up of 20 months, survival rate was 84% in group 1 and 74% in group 2 (p=0.11), including operative mortality of 7% and 13% (p=0.42). Through effective volume reduction (LVEDVI 41%; LVESVI 49%) systolic function improved immediately after SVR (LVEF 27-39% in group 2, p<0.05). Worsening of diastolic function was specifically observed after SVR within the first year (E/A-ratio 1.38-1.74 cm/s, p=0.02). Recurrent mitral regurgitation (p=0.004) and secondary remodeling (p=0.01) were major determinants of decreasing LV compliance. Clinical outcome in terms of cardiac events and survival was compromised by restrictive diastolic function (p=0.02) and increased LV volumes (p=0.04).

CONCLUSION

SVR in addition to coronary revascularization and restrictive mitral annuloplasty results in significant clinical improvement in selected patients with advanced ischemic heart disease and severely dilated ventricles. SVR entails immediate improvement of systolic function, which remains sustained during short-term follow-up. Serial assessment of diastolic function is mandatory as LV compliance seems more sensitive to early changes induced by recurrence of mitral regurgitation and secondary ventricular dilation. Moreover, worsening of diastolic dysfunction should be timely recognized because of its adverse clinical impact.

Stentless and stented aortic valve replacement in elderly patients: factors affecting midterm clinical and hemodynamical outcome

OBJECTIVE

To report on the midterm results of aortic valve replacement (AVR) with stented and stentless bioprosthesis in an elderly population by analyzing the factors affecting survival and hemodynamical performance.

METHODS

In a retrospective study, 145 patients with a Toronto stentless prosthesis are compared with 110 patients with a stented Carpentier-Edwards valve. The 5- to 10-year clinical outcome, transprosthetic gradients, and early and late left ventricular mass (LVM) regression are analyzed in view of specific prosthesis- and patient-related factors.

RESULTS

Actuarial survival at 5 years is 82% after stentless AVR versus 68% after stented AVR (p < 0.001) in elderly patients. However, there was no difference in survival at 8 years, being 55.9% and 59.5%, respectively. Univariate analysis revealed that advanced age at the time of operation, NYHA class IV, use of a stented xenograft, presence of patient-prosthesis mismatch (PPM) (IEOA < or = 0.85 cm2/m2), and severe preoperative left ventricular (LV) hypertrophy (LVMI > 180 g/m2) affected survival adversely. But multivariate analysis determined only age, NYHA class IV and excessive LV hypertrophy as independent predictors of late mortality. Stented and stentless xenografts were equally effective in terms of transprosthetic gradients and LVMI regression. The use of a stentless valve significantly reduced the occurrence of PPM (18% vs 41%, p < 0.01). Early LVMI regression at 1 year was optimized by the avoidance of PPM, indicated by a higher absolute (43.7+/-28.3 g/m2 vs 58.6+/-33.8 g/m2, p = 0.003) and relative (25.0+/-12.7% vs 31.4+/-14.9%, p=0.004) mass regression. However, late LV remodeling was predominantly affected by systemic hypertension and severe preoperative LV hypertrophy, resulting in the incomplete LVMI resolution in 61.3% and 66.7% of these patients, respectively.

CONCLUSION

In elderly patients, aortic valve replacement appears to be equally effective with a stentless or stented bioprosthesis. Midterm clinical outcome is mainly determined by patient-related factors such as age, advanced NYHA class, and severity of preoperative LV hypertrophy. Regarding post-AVR left ventricular remodeling, patient-prosthesis mismatch influences the early phase, whereas arterial hypertension affects the late regression more. However, the left ventricular remodeling is continuously compromised by the preoperative presence of excessive hypertrophy, despite the efficacy of the aortic valve replacement.

Operative outcome of minimal access aortic valve replacement versus standard procedure

BACKGROUND

to determine the advantages and/or risks of minimal access aortic valve replacement compared to standard sternotomy procedure.

METHODS

from January 1997 to December 2001, 271 consecutive adult patients underwent isolated aortic valve replacement of which 174 underwent a minimal access procedure (Group 1) and 97 a standard procedure (Group 2). The preoperative variables of both groups were comparable. Retrospective analysis of postoperative outcome was performed.

RESULTS

follow-up was complete and ranged from 6 months to 4 years. Overall in-hospital mortality was 3.3% (respectively 2.8 and 4.1%). No statistical difference was noted regarding operative time variables, mortality rate and hospital stay. There was a significant higher incidence of revision (p = 0.018) and late pericardial effusion (p = 0.022) in the minimal access group. Also trends were in favour of the standard group for incidence of postoperative pneumothorax and pericarditis constrictiva.

CONCLUSIONS

minimal access aortic valve replacement is a safe and reliable technique, but carries the risk of incision-related morbidity. Proper patient selection and perioperative management is mandatory.

Lower-intensity anticoagulation for mechanical heart valves: a new concept with the ATS bileaflet aortic valve

BACKGROUND AND AIM OF THE STUDY

The design of the bileaflet ATS mechanical valve incorporates an open pivot at the hinge mechanism. Total washout of blood at the pivot area seen using three-dimensional computational fluid dynamics modeling may make the valve less vulnerable for clot formation in patients without major thromboembolic risk factors.

METHODS

Between January 1993 and June 1999, the ATS valve was implanted in the aortic position in 286 consecutive patients. Patients were allocated prospectively to two groups: group 1 comprised patients in regular sinus rhythm with good left ventricular (LV) function (n = 144); group 2 included patients in non-sinus rhythm and/or with large hypocontractile left ventricles (n = 142). The anticoagulation regime in group 1 was to achieve an INR of 1.5-2.5, rather than to maintain INR strictly at 2.5-3.5 for mechanical valves (as in group 2).

RESULTS

Follow up was 99% complete and ranged from 50 to 120 months. Survival (Kaplan-Meier) was respectively 95% and 90% and 90% and 83% at 2 and 5 years in favor of group 1 (p = 0.0055). Multivariate analysis selected advanced age, poor LV function and 'erratic' INR as risk factors for death. Log rank analysis failed to detect any statistical difference in thromboembolism. Bleeding occurred more frequently in group 2 (p = 0.018); independent risk factors for bleeding were the presence of aspirin (p = 0.0164) and advanced age (p = 0.02).

CONCLUSION

The excellent group 1 data and outcome encouraged continuation of the low-intensity anticoagulation regime, and should be regarded as a new concept for the treatment of mechanical valve patients.

Off-pump coronary surgery: surgical strategy for the high-risk patient

OBJECTIVE

In a retrospective study, we compared two groups of consecutive patients operated by the same team during the year 2000 for coronary artery disease with the use of extracorporeal circulation (group 1, n=230) or on the beating heart using the Octopus II plus stabiliser (group 2, n=228). High-risk patients were identified by a EuroSCORE plus 6. EuroSCORE definitions and predicted risk models were utilized to compare the variables of the groups.

METHODS

There were no significant differences between the preoperative variables of the groups in age, gender, left ventricular function, diabetes and peripheral vascular and renal disease as is indicated by the Euroscore (resp. 4.7/5.1 p=0.107). Calcification of the ascending aorta and chronic obstructive lung disease were statistically significant more prevalent in the beating heart group. No differences in preoperative variables in the high-risk patients group (Euroscore 8.5/8.1 p=0.356) except for calcification of the ascending aorta.

RESULTS

All patients underwent a full revascularisation through a midline sternotomy. Significant more distal anastomoses were performed in group 1 (3.7 per patient (1-6)) with regard to group 2 (2.9 per patient (1-6)). Anesthesia, postoperative treatment and follow up were equal for both groups. A significant lower incidence of atrial fibrillation (p=0.010), shorter ICU stay (p=0.031) and renal insufficiency (p=0.033) was reported in group 2. In the low risk group, we could not diagnose any difference between the two groups, except for atrial fibrillation. The benefits of the beating heart surgery however were more pronounced in the high-risk patient as is indicated by a significant reduction of the ICU stay by 1 day (3.5d/2.5d (p=0.028)), better preservation of the renal function (p=0.017) and a significant reduction of the length of hospital stay by more than two days (p=0.040). A lower incidence of atrial fibrillation, however not significant.

CONCLUSION

In our experience, beating heart surgery is a safe alternative for conventional coronary heart surgery. High-risk patients do benefit most from this technique. It became our first choice in the elderly patient and patients presenting with higher co-morbidities.

An experimental model of coronary anastomosis without suturing

OBJECTIVE

The aim of the study is to explore the feasibility and mid-term patency of an easier anastomotic technique for Minimally Invasive Direct Coronary Bypass Grafting (MIDCAB).

METHODS

Eight mongrel dogs (+/-15 kg) underwent direct anastomosis between the left internal thoracic artery (LITA) and the left anterior descending coronary artery (LAD) via inferior sternotomy on the beating heart. After positioning the graft, the distal part of the LAD was opened to allow retrograde filling of the LITA-graft. The anastomosis was secured by the use of biological glue (BioGlue, Cryolife, Marietta, GA, USA). No intravascular suture material was used. Ischemic time averaged 6 min. The proximal LAD was occluded upstream the arteriotomy. All survivors were angiographically controlled for patency after 6-8 weeks. Consequently, four dogs were sacrificed after 6 weeks and the remaining after 3 months for anatomo-pathological and histological examination by light and electron microscopy of the anastomotic site.

RESULTS

All procedures were successful except for one animal that died of uncontrollable bleeding at the anastomotic site. Another sustained post-operative transmural anterior myocardial infarction due to a late graft occlusion. All angiographically controlled grafts were patent with two vascular strings near the anastomotic site. Histology showed early macrophage infiltration into the glue. At post-mortem examination, new endothelialization was noticed in 80% of the cases. However, ultrastructural examination detected marked differences in endothelial fibroblastic lining compared to normal histology.

CONCLUSIONS

Good mid-term permeability of the LITA grafts was observed in this new anastomotic technique for MIDCAB in the canine model. Although neo-endothelialization was present in most cases, ultrastructural differences were noticed after 3 months in the neo-intima compared to normal.

Lower anticoagulation for mechanical heart valves: Experience with the ATS bileaflet valve

BACKGROUND

The design of the bileaflet ATS (ATS Medical Inc., Minneapolis, USA) mechanical valve incorporates an open pivot at the hinge mechanism. Total washout of the blood at the pivot area was observed using 3-D computational fluid dynamics modelling. This phenomenon could make the valve less vulnerable to clot formation in patients without major thromboembolic risk factors.

METHODS

From January 1993 to June 1999, 286 consecutive patients had the ATS valve inserted in the aortic position. Patients were divided into two groups. Group 1 comprised all patients in regular sinus rhythm with good left ventricular function (144 patients). Group 2 included patients in non-sinus rhythm and/or with large hypocontractile left ventricles (142 patients). The anticoagulation regime in group 1 was used to obtain an international normalised ratio (INR) between 1.5 and 2.5. This contrasts with our regular aim to maintain the INR strictly between 2.5 and 3.5 for all mechanical valves, as achieved in group 2.

RESULTS

The follow-up period (99% completeness) ranged from 18 to 84 months. Survival (Kaplan-Meier) was 97 and 98% and 92 and 81% at 1 and 5 years in group 1 and group 2, respectively (P = 0.12). Log rank analysis failed to detect a statistical difference in thromboembolism or bleeding between both groups (P > 0.05). However, trends were in favour of group 1. Univariate analysis selected poor ventricular function and an 'erratic' INR value (P = 0.002) as risk factors for death. The sole independent risk factor for bleeding was the use of aspirin (P = 0.025).

CONCLUSIONS

The excellent group 1 data and outcome encouraged us to continue our low intensive anticoagulation regime and perhaps should be regarded as a new concept for treatment of selected mechanical valve patients.

Effects of off-pump coronary surgery on the mechanics of the respiratory system, lung, and chest wall: Comparison with extracorporeal circulation

OBJECTIVE

To compare the effects of cardiac surgery with and without extracorporeal circulation on the mechanics of the respiratory system, lung, and chest wall. We also determined the time course of those effects.

DESIGN

Prospective, controlled study.

SETTING

An eight-bed, cardiac-surgical intensive care unit at a university hospital.

PATIENTS

Two groups of patients scheduled for elective coronary bypass surgery were studied: ten patients with extracorporeal circulation and 13 patients without extracorporeal circulation.

INTERVENTIONS

Measurement of esophageal pressure after insertion of an esophageal balloon catheter to separate respiratory system mechanics into lung and chest wall components. Measurements were performed preoperatively after induction of anesthesia (control), immediately postoperatively at arrival in the intensive care unit (time 1), and after 3 hrs (time 2). In 12 of the 23 patients, measurements were also performed 6 hrs postoperatively (time 3).

MEASUREMENTS AND MAIN RESULTS

No significant differences concerning demographics or surgical procedure were noticed between the two groups. Respiratory system, chest wall, and lung mechanics were obtained using the technique of rapid airway occlusion during constant-flow inflation. In both the group with and without extracorporeal circulation there was a significant increase in static and dynamic elastance of the respiratory system and lung at times 1 and 2, which tended to decrease again at time 3; chest wall elastance significantly increased at times 2 and 3 in the group without extracorporeal circulation, whereas the increase in chest wall elastance in the group with extracorporeal circulation occurred earlier (also at time 1). Additional resistance of the respiratory system and lung remained unchanged; chest wall resistance, however, significantly increased in both groups. Work of breathing significantly increased in both groups at times 1 and 2. There was a significant reduction in the Pao2/Fio2 ratio in both groups at times 2 and 3. No significant differences between the groups at any moment were noticed.

CONCLUSIONS

Coronary bypass surgery with and without extracorporeal circulation results in dramatic impairment of respiratory system mechanics. Based on respiratory system mechanics, early extubation after coronary artery bypass grafting should be performed with caution, no matter whether the off-pump or cardiopulmonary bypass technique is used.

Tissue factor as the main activator of the coagulation system during cardiopulmonary bypass

OBJECTIVE

This study investigates the influence of foreign material and blood aspirated from nonvascular structures on activation of coagulation, hemolysis, and blood loss.

METHODS

The series comprises 3 randomized groups (groups C, S, and S+P) of 10 patients undergoing routine coronary artery bypass grafting with cardiopulmonary bypass. In group C, the control group, all aspirated blood was returned into the circulation. In group S suction blood was discarded, whereas group S+P was identical to group S, with surfaces coated with phosphorylcholine. Plasma concentrations of beta-thromboglobulin, thrombin generation, haptoglobin, and free hemoglobin, as well as blood loss, were measured.

RESULTS

A steady increase in free plasma hemoglobin, as well as an increased generation of thrombin, was noticed in group C. Moreover, a close correlation (r = 0.916) between the generation of thrombin and its inhibition (thrombin-antithrombin complexes) was observed. Platelets were clearly activated in group C and, to a lesser extent, in group S. In contrast, platelet activation in group S+P was negligible, resulting in a 30% decrease in blood loss (P =.05).

CONCLUSIONS

Aspirated blood contaminated by tissue contact is the most important activator of the coagulation system and the principal cause of hemolysis during cardiopulmonary bypass. Contact with a foreign surface is not a main variable in the procoagulant effect of bypass. Mimicking the outer cell membrane structure resulted in decreased platelet activation and decreased blood loss.

Phosphorylcholine coating offers natural platelet preservation during cardiopulmonary bypass

Return of blood activated by tissue factor is the main culprit for triggering the coagulation cascade. When this activated blood is diverted from the cardiopulmonary bypass (CPB) circuit, it becomes possible to evaluate the effect of surface treatment on platelet and complement activation. Twenty adult patients undergoing elective coronary artery bypass grafting (CABG) were randomly assigned either to a control group (n=10) or to a group in which the CPB circuit was completely coated with phosphorylcholine (n=10). Plasma concentrations of platelet factor 4 (PF4), beta-thromboglobulin (betaTG), C3, C3d, C4, TCC, thrombin generation, haptoglobin and free haemoglobin, as well as blood loss, were measured. No significant differences between the two groups were found for haemolysis and thrombin generation. The mean total release of PF4 and betaTG during CPB was 9338+/-17303 IU/ml/CPB and 3790+/-4104 IU/ml/CPB in the coated group versus 22192+/-13931 IU/ml/CPB (p=0.011) and 8040+/-3986 IU/ml/CPB (p=0.005) in the control group. Blood loss was 30% less in the coated group compared to the control group. Phosphorylcholine coating appears to have a favourable effect on blood platelets, which is most obvious after studying the changes during CPB. Clinically, this effect resulted in a 30% reduction in blood loss.

Redo mitral surgery using the Estech endoclamp

BACKGROUND

Redo-CABG surgery remains extremely hazardous in the presence of open bypass grafts. In our patients with mitral valve pathology with open and well-functioning bypass grafts, we explored alternative approaches in order to avoid damage to the grafts by extensive dissection and direct clamping of the ascending aorta. The "Estech procedure," which uses the Estech remote access perfusion (RAP) endoclamp catheter (Estech Inc., Danville, CA), was selected for these patients.

METHODS

From January 1998 to January 2000, 10 patients underwent an Estech procedure for redo mitral surgery. All patients had previous cardiac operations such as coronary artery bypass grafting (CABG) and/or mitral valve procedures. The Estech procedure consisted of an anterior left thoracotomy and peripheral cannulation at femoral site using the Estech endovascular balloon technique. The series was comprised of seven mitral valve replacements, two valve reconstructions, and one closure of a paravalvular leak. One procedure had to be converted to a standard re-sternotomy due to extreme arteriosclerosis of the descending aorta with plaque dislocation at the time of catheter insertion. However, no damage was inflicted to the open bypass grafts.

RESULTS

The follow-up period ranged from six to 30 months and was 100% complete. We encountered one hospital death in our group, which was due to a late post-operative intestinal infarction and multiple organ failure (MOF), and was not procedure related. As expected, morbidity was high in this compromised cohort, but no late death has occurred prior to submission of this article. All survivors progressed to an acceptable NYHA functional class.

CONCLUSION

The excellent results in this complex patient group inspired us to use the Estech procedure as a standard approach for redo mitral surgery.

Feasibility of a pumpless extracorporeal respiratory assist device

BACKGROUND

Our study evaluated the efficacy and feasibility of a pumpless respiratory assist device and determined its capacity for carbon dioxide removal.

METHODS

In five adult pigs the left femoral vein and artery were cannulated with a 20F cannula and connected to a low-pressure hollow-fiber artificial lung. After we had obtained baseline values of mean arterial pressure, cardiac output, and blood flow across the artificial lung, the mean arterial pressure was reduced 20% and 40% relative to baseline; in a second phase, it was raised 20% and 40. Cardiac output and artificial lung flow were simultaneously recorded. We determined the carbon dioxide removal capacity of the artificial lung by gradually increasing the arterial partial carbon dioxide tension of the animal.

RESULTS

An increase of 10 mm Hg in mean arterial pressure resulted in an increase of flow of 0.14 L/min. The mean pressure drop across the artificial lung was measured at 17 +/- 9 mm Hg. The shunt flow over the artificial lung varied between 14 and 25% of the cardiac output of the animal. Depending on inlet conditions, carbon dioxide removal by the artificial lung was between 62 +/- 22 mL/L/min and 104 +/- 25 mL/L/min.

CONCLUSIONS

A pumpless respiratory assist device can remove a significant proportion of the metabolic carbon dioxide production. However, adequate mean arterial pressure is mandatory to maintain sufficient flow across the device. The technique seems attractive because of its simplicity and can be used in acute lung injury in conjunction of apneic oxygenation for prolonged respiratory support.

Stentless or stented aortic valve implants in elderly patients?

OBJECTIVE

To assess differences in indication and mid-term results between stentless and stented procedures in elderly patients, we followed aortic valve patients over a period of 5 years.

METHODS

In a consecutive series of 154 elderly aortic patients in regular sinus rhythm from 1992 to 1997, we inserted 103 stentless (Toronto SPVTM, St Jude Medical Inc., St Paul, Minneapolis, MN) and 51 stented (Carpentier-Edwards supra annular porcine, Baxter Inc., Irvine, CA) bioprostheses in the aortic position.

RESULTS

All 154 patients seemed preoperatively eligible for a stentless procedure. Mean age was 74.8 years (range 67-86 years) with a majority of female patients. The surgeon's (in)experience, major dilatation or calcifications of the ascending aorta and aberrant coronary anatomy were the most common reasons for drawback from the stentless procedure (51/154 patients). Aortic clamp time was significantly higher in the stentless vs. stented group (70 vs. 57 min, P < 0.0001). The large average 25.3 mm size of the stentless prostheses (vs. 23.7 mm stented) stands in full contrast with the low mean body surface area of 1.68 m2 (vs. 1.70 m2) of the patients. We encountered. respectively. 5 and 2 hospital-deaths (P = n.s.). The follow-up period ranged from 6 to 66 months and was 97% complete, yielding, respectively, 302 and 139 patient-years. Survival (Kaplan-Meier method) was statistically higher in favor of the stentless procedures (log rank: P = 0.03). All survivors progressed markedly to a mean postoperative NYHA class 1.3 respectively, 1.4 (vs. preop. 3.3 and 3.2). Echocardiographic transvalvular gradients compared favorable for the stentless group in the small under 25 mm valves (P = 0.02 for 23 mm sized valves between groups) with improved left ventricular function and a significant decrease of left ventricular end diastolic diameter (LVEDD 48.0 vs. 56.5 mm) at 1 year follow-up. Cusp calcifications on control echocardiography were detected earlier (beyond 3 years) in the stented group, without signs of early significant regurgitation or dysfunction in both groups, except for one patient necessitating re-operation.

CONCLUSION

Although the implantation technique is much more demanding for stentless procedures, reflected by a longer aortic clamp-time, and remains impossible in some cases, elderly, small sized patients take full benefit of their large, non-obstructive prostheses.

Familial dilated cardiomyopathy and spontaneous ventricular arrhythmias

Two members of a family with (autosomal dominant) dilated cardiomyopathy and symptomatic short-lasting ventricular tachyarrhythmias were each treated with an ICD in the course of their disease. One patient had an episode of torsades de pointes induced by amiodarone, and the ICD failed to recognize some events. Cardiac arrest recurred in this setting. Treatment with bisoprolol was helpful in maintaining an acceptable functional status and in preventing multiple shocks until transplantation became mandatory. Bisoprolol was not tolerated by the second patient, who had several episodes of syncope because of nonsustained ventricular tachycardia. His functional course went downhill fast, and he received a heart transplantation 16 months after implantation of an ICD, which had not delivered any shocks, in spite of one symptomatic short ventricular tachycardia.

Clinical experience with the first 100 ATS heart valve implants

Between May 1992 and March 1994, 100 consecutive patients had 119 new ATS mechanical bileaflet valves inserted (61 aortic, 50 mitral, eight tricuspid). The mean age of the patients was 63.7 (range 13-82) years. The follow-up period ranged from 5 to 27 months and was complete in all cases. Before surgery, 53 aortic valve patients were in New York Heart Association functional class III or higher. This improved to a mean of 1.3 postoperatively, all patients being in classes I or II. One patient died in hospital, and another 3 months after implantation (actuarial survival rate 98%). One patient had an embolic event 9 days after an aortic valve reoperation which caused a parietal infarction. One tricuspid valve blocked in the open position 6 weeks after implantation as a result of inadequate anticoagulation and was successfully unblocked after 2 days of intensive thrombolytic therapy. Patients were treated by mild anticoagulation without developing bleeding complications. Echocardiographic, transoesophageal and transthoracic valvular gradients compared favourably with the gradients reported in other mechanical valves (including small aortic valves). The haemodynamics were excellent without evidence of significant regurgitation. This was confirmed by an in vitro hydrodynamic evaluation of the valve using a pulse duplicator system. The valve closure caused little noise and was as a result well tolerated.

Toronto stentless aortic valve replacement in elderly patients

From July 1992 to October 1994, we inserted new Toronto SPV stentless aortic heterografts (SJM Med. Inc., St Paul, Minneapolis, USA) in 40 of a series of 50 consecutive patients older than 70 years. The mean age was 75.7 years (range 70 - 86 years). All, except 4 patients, were pre-operatively in NYHA functional class III or higher. The aortic clamp time was significantly higher in the stentless groups (75 v. 53 minutes, P < 0.001). The average 25.5 mm size of the implanted valves stands in stark contract to the low body surface area (1.69 m2) of this patient groups. The surgeon's (in)experience was the major reason for the drawbacks (5/50) associated with a stentless procedures. The follow-up period ranged from 2 to 27 months and was complete in 100% of cases. We encountered 1 hospital death and no late deaths (97.5% actuarial survival). The mean NYHA class at follow-up was 1.5, and without exception patients were in class I or II. We noted one transient ischaemic attack immediately postoperatively and another later incident in a patient with a previous severe vascular history. With a low-intensity anticoagulation regiment for the first 3 months, there were two incidents of haemorrhaging necessitating premature anticoagulation withdrawal. Echocardiographic transthoracic valvular gradients compared favourably with the reported gradients of other biological valves, especially the smaller ones the significantly better haemodynamics were noted in most cases 6 months after implantation. Comparison of data with stented valves implanted during the same period indicates that the average size of the stentless valves was significantly higher (22.3 v. 25.5 mm, P < 0.001) in an equivalent population.

Valve replacement with the ATS open pivot bileaflet prosthesis

OBJECTIVE

We sought to evaluate the ATS open pivot bileaflet valve with respect to haemodynamics and thromboembolism.

METHODS

We prospectively studied 200 consecutive patients aged 13-80 years. One hundred and nineteen aortic, 103 mitral and 11 tricuspid valves were replaced in 172 single, 23 double and 5 triple valve procedures. Thirty-eight were re-operations and 51 underwent coronary bypass. Transvalvular gradients were determined by transoesophageal and transthoracic echocardiography. Patients were followed for 12 months to 3 years.

RESULTS

There were four hospital (2%) and three late deaths, each non-valve related. Two patients were reoperated for partial valve dehiscence. One aortic reoperation patient suffered a potential transient thromboembolic event. One tricuspid prosthesis thrombosed after anticoagulation was discontinued but thrombolysis resolved this problem. There were no other thromboembolic events. Valve gradients were equivalent or better than those for other bileaflet valves.

CONCLUSIONS

The ATS valve has excellent haemodynamic characteristics and a very low thromboembolic rate, probably related to the convex self-washing hinge mechanism. Consequently, we have reduced anticoagulant levels to INR (international normalised ratio) 1.5 to 2.0 for aortic valve patients in sinus rhythm. Early experience suggests that the ATS valve functions well in the tricuspid position.

Tricuspid valve replacement: postoperative and long-term results

A series of 146 consecutive patients who underwent tricuspid valve replacement at the University Brugmann Hospital between 1967 and 1987 was reviewed. Mean age at operation was 51.4 years (+/- 12.1 years). Different types of prostheses were implanted including porcine and bovine pericardial bioprostheses and older and bileaflet mechanical valves. Most patients were severely disabled by their cardiac disease before operation, with 30.1% in New York Heart Association functional class III and 69.9% in class IV. Operative mortality and hospital mortality rates (30 days) were high (16.4%). Incremental risk factors for hospital death included icterus (p < 0.005), preoperative hepatomegaly (p = 0.012), and New York Heart Association functional class IV (p = 0.013). Multivariate analysis only selected preoperative icterus (p < 0.01) as being independently significantly related to hospital mortality. The hospital survivors were followed up for a median of 94 months. A complete follow-up was available for all patients except two for 30 months or more. At 30 months the only two significant parameters were the type of myocardial protection (p = 0.024) and the year of operation (before 1977 or after [precardioplegia era or after], p = 0.011). There were 70 late deaths during the entire follow-up period. The univariate (log-rank statistics) incremental risk factor for late death was the type of tricuspid prosthesis (Smeloff-Cutter and Kay-Shiley versus St. Jude Medical versus bioprosthesis) (p = 0.04). A trend was observed for the type of operative myocardial protection (normothermia and coronary perfusion) (p = 0.06) and preoperative New York Heart Association functional class IV (p = 0.055). Actuarial survival was 74% at 60 months and 23.4% at 180 months. Cumulative follow-up added up to 1015 patient-years. In a more detailed analysis of the effect on survival of the type of tricuspid prosthesis, a significant difference was observed between the bioprostheses and some older mechanical prostheses (Smeloff-Cutter and Kay-Shiley) (p = 0.04) but not between the bioprostheses and the bileaflet valves (p = 0.15). When the follow-up period was stratified according to less than 7 years and more than 7 years of follow-up, no difference was observed for the first period, but for the late follow-up the new mechanical prostheses did better than the bioprostheses (p = 0.05), suggesting a degradation of the bioprostheses after 7 years and favoring mechanical prostheses for those patients with a good long-term prognosis.

Trapped venous embolus in a patent foramen ovale causing recurrent paradoxical embolism

The combination of deep venous thrombosis, patent foramen ovale and arterial emboli suggests the diagnosis of paradoxical embolism. In these cases, only very rarely, a causal relationship between the venous thrombus and the patent foramen can be established. An instructive case of trapped venous embolism within the foramen ovale is described proving a causal relationship between arterial embolism and its venous origin.

Transcatheter treatment of angina after coronary surgery due to concomitant internal mammary steal and right coronary artery stenosis: a need for staging

Unligated side branches of the internal mammary artery used as a conduit in bypass surgery can be responsible for a flow steal phenomenon, causing recurrent angina. In this report we describe such a case, which was treated with a transcatheter embolization technique using coils as an alternative to surgery. However, heparin administration for simultaneous balloon dilatation of another lesion delayed successful embolization. Whenever balloon dilatation and embolization have to be performed on the same patient, both procedures should be staged to avoid heparin administration during and after the embolization procedure.

Clinical evaluation of a new hollow fibre membrane oxygenator

Twelve consecutive patients undergoing elective cardiac surgery were perfused with the Cobe Optima hollow fibre oxygenator. Gas transfer characteristics and blood handling were studied. The device had a maximum oxygen transfer of 315 ml/minute. The average shunt fraction was 4.5%, and was not influenced by blood-flow rate. Mean platelet count declined slightly to 91% of the baseline at the end of the study period. Haemolysis was evaluated by monitoring serum-free haemoglobin, serum haptoglobin and serum haemopexin. The evolution was as follows: free haemoglobin increased from 14 +/- 5 mg/100 ml to 85 +/- 0.8/100 ml (p = 0.01) at the end of bypass; haptoglobin decreased from 1.33 +/- 0.90 g/l to 0.89 +/- 0.15 g/l (p = 0.01); and haemopexin decreased from 0.84 +/- 0.13 g/l to 0.74 +/- 0.15 g/l (p = nonsignificant). In all patients the residual capacity of serum haptoglobin to protect against haemolysis was satisfactory. All patients had an uneventful postoperative course.

Aortobronchial fistula: a late complication of coarctation repair by patch aortoplasty

A case of aortobronchial fistula occurring 13 years after coarctation repair by patch aortoplasty is presented. Correct diagnosis was established by computed tomographic scanning and magnetic resonance imaging. Surgical treatment consisted of simple closure of the bronchial defect and interposition of a Dacron graft under partial extracorporeal bypass.

Diagnostic and therapeutic value of thoracotomy in advanced pulmonary neoplasms

This study analyses retrospectively 100 consecutive thoracotomies performed for lung cancer before end 1986. Chest CT scan assessed mediastinal lymph node disease, chest wall invasion and mediastinal invasion, with an overall accuracy of 75, 93 and 91 per cent respectively; mediastinal lymph node disease was significantly more underestimated in the stage III group. Characteristics, type of surgical and adjuvant therapy and follow-up were analysed in the T3 (16 patients) and the N2 (18 patients) group. Complete resection was possible in only a minority of the cases: 3 in the T3 group and one in the N2 group. Of the T3 group, 3 patients have survived more than 3 years and 3 are actually still alive. Of the N2 group, only 2 patients are still alive. Most deaths were due to generalization of the disease.

A patient with two chronic posttraumatic aneurysms of the thoracic aorta

A case of successful replacement of two coexistent chronic post-traumatic aneurysms of the thoracic aorta is presented. Presumably, these aneurysms at the aortic isthmus and the descending thoracic aorta resulted from two different deceleration traumas.

Aortocolic fistula caused by an ingested chicken bone

Primary aortocolic fistulas are a rare but lethal complication of aortic or iliac aneurysms. A case of fistula between a nonaneurysmal aortic bifurcation and sigmoid colon caused by an ingested chicken bone is presented. This cause of rectal bleeding, which has never been described, might have been suspected after careful examination of abdominal x-ray films. Surgical management included removal of the foreign body and primary repair of the colonic and aortic rent and appeared to be adequate.

Comparison of auscultation, continuous wave Doppler imaging, intravenous digital subtraction angiography and conventional angiography in diagnosis of carotid artery disease

The reliability of auscultation, continuous wave (CW) Doppler imaging, and intravenous digital subtraction angiography (IV DSA) in the assessment of carotid artery disease has been evaluated in comparison with conventional angiography in 30 patients. With auscultation, specificity and sensitivity for internal carotid artery (ICA) stenosis of 50% or more were 81% and 67% respectively. CW Doppler imaging detected ICA stenosis of 50% or more with a sensitivity of 83% and a specificity of 92% and ICA occlusion with a sensitivity of 60%. The specificity of IV DSA was 95% and the sensitivity for ICA stenosis of 50% or more and ICA occlusion were 75% and 100% respectively. Combining CW Doppler and IV DSA findings raised sensitivity for ICA stenosis of 50% or more and ICA occlusion to 89% and 100% respectively and specificity to 95%. The combination of CW Doppler and IV DSA is a safe and accurate test battery in the detection and categorization of carotid disease.

Transaxillary thoracotomy for treatment of spontaneous pneumothorax

This study reports the retrospective analysis of operative treatment of 20 cases of spontaneous pneumothorax during the last 4 years. Surgical indications included recurrence, recollapse of the lung on clamping the chest tube, nonexpansion of the lung despite adequate drainage or persistent air leak, and giant bulla. A transaxillary thoracotomy was used in all cases to treat sites of air leak and subpleural blebs by resection (14 cases) or oversutering (4 cases) combined with pleural abrasion (19 cases) or apical pleurectomy (1 case). This approach has met with excellent results without major morbidity or mortality.

Femorofemoral bypass grafting in high-risk patients

A total of 37 extra-anatomic femorofemoral bypasses were inserted for severe unilateral iliac artery stenosis or a thrombosed graft limb of an aorto-bifemoral bifurcation graft. All patients were severely debilitated and at high risk for direct aorto-iliac reconstruction. 30% suffered severe claudication; 70% had ischemic restpain or trophic lesions. 43% died during a mean follow-up period of 17 months. This study demonstrates that the extra-anatomic femoro-femoral bypass procedure is an effective alternative therapeutic modality for high-risk patients with an acceptable operative mortality (5.4%) and morbidity to improve the quality of life.

Fibromuscular dysplasia of the internal carotid artery

An observation on symptomatic fibromuscular dysplasia of the internal carotid artery, surgically treated by graduated internal dilatation is presented. Fibromuscular dysplasia is a segmental, nonatheromatous disease of small to medium-sized arteries, affecting mainly renal arteries. Involvement of the internal carotid artery is often an incidental angiographic finding in asymptomatic patients, but can be associated with specific neurologic symptoms requiring surgical treatment. The histopathologic character, the pathogenesis, the clinical manifestation, the diagnosis and the therapeutic possibilities of this affection are discussed.

Fasciitis necroticans

Fasciitis necroticans (F.N.) is a rapidly progressing necrotizing process of subcutaneous tissue and fascia which results in large soft tissue defects and severe systemic toxicity. During the last five years nine patients with F.N. were admitted at our department of surgery. Antibiotic prophylaxis immediately after the eliciting trauma was associated with a significant delay in treatment. Early recognition and surgical treatment are the most important factors influencing survival.

Small artery syndrome in women

During the past four years, 106 women underwent aortography and peripheral runoff studies for peripheral vascular disease. Eleven patients presented with "small vessels" and were selected for this study. They were significantly younger than the rest of the group (a mean age of 52 versus 66 years). A clear history of claudication was elicited in all patients. Rest pain was present in four patients. Most patients were small in stature but not obese. Weak or absent femoral and distal pulses and abdominal or femoral bruits were common. Angiography demonstrated a narrow infrarenal aorta, narrow iliac and common femoral arteries and a straight course of iliac arteries. Atherosclerotic lesions involved mainly the aortoiliac segment, but were confined to the superficial femoral artery in two patients. Reconstruction was achieved by endarterectomy or transluminal angioplasty in segmental aortoiliac disease and aortobifemoral or aortobi-iliac graft in diffuse disease. Femorpopliteal or iliopopliteal graft or lumbar sympathectomy was performed in patients with significant femoral disease. In one patient, an acutely occluded femoral segment was replaced by a venous interposition graft. Two patients were treated conservatively. There were no operative deaths. Nine patients were markedly improved at follow-up examination. Graft thrombosis occurred in one patient with combined aortobi-iliac and iliopopliteal graft. The high incidence of single bifurcating lumbar arteries at the fourth and fifth lumbar vertebrae supports the hypothesis that aortic hypoplasia may result from embryonic overfusion of the dorsal aortas. Lipid abnormalities existed in 54 per cent of the patients. All women were heavy smokers and 73 per cent had a positive family history of cardiovascular disease.

[Systematic research on an etiology in apparently primary deep venous thrombosis. Apropos of 59 cases]

Primary deep vein thrombosis was confirmed by phlebography in 59 cases between Jan. 1981 and Jan. 1984 in the department of Cardiovascular Surgery of the Academic Hospital of the V.U.B. Brussels. Investigations conducted in all patients included blood and urine analyses, chest radiography, electrocardiogram, gynecologic or urologic examinations and abdominal and pelvic ultrasound imaging. Findings demonstrated one or more risk factors in 92% of cases, the principal ones being obesity, a history of thromboemboli and, in women, the use of oral contraceptives. Nine patients had cancer and 4 of these received combined surgery-chemotherapy. All cases of so-called primary deep vein thrombosis should be investigated routinely for risk factors, because of the need and possibilities for treatment in some of them, particularly since procedures are non-invasive, of low cost, and easily performed during initial heparin therapy.

Administration of caerulein to rats promotes antral epithelial cell renewal

The growth-promoting effect of caerulein on antral gastric mucosa was explored using Wistar rats. Implanted osmotic minipumps were used to administer submaximal doses of either caerulein or saline to normal rats for up to 4 days. In one group, reflux of bile and pancreatic juice into the stomach was avoided by previous surgical diversion of the distal common bile duct to the jejunum. DNA synthetic and mitotic activity in the antrum epithelium were estimated by 3H-thymidine pulse labelling and autoradiography during the administration of the peptide. The rate of cell migration was determined in animals killed 1, 2 and 3 days after the 3H-thymidine pulse. Administration of caerulein to normal rats provoked significant increases in both labelling and mitotic indices, and a significant acceleration of the upward cell migration in the glandular tubes. In the animals with distal diversion of bile and pancreatic secretions both labelling and mitotic indices were also increased over control values under the effect of the peptide. These data indicate that administration of caerulein stimulates cell proliferation in the antral gastric mucosa. This effect cannot be explained through increased reflux of pancreaticobiliary secretions in the stomach.

Refeeding of fasting rats stimulates epithelial cell proliferation in the excluded colon

The major postprandial factors known to influence epithelial cell proliferation in the colon are intraluminal factors. In this study, a transverse colostomy was created in rats in order to avoid the intraluminal stimulation of the distal colon after feeding. After a 48-h fasting period, the animals were refed whereas controls were kept fasted. Refed animals with their controls were killed at respectively 0, 8, 12, 18, and 24 h after the time of refeeding. Autoradiography of in vitro labeled mucosal samples was used for determining the proliferative parameters in the colonic crypts. The uptake of [3H]thymidine in mucosal scrapings was measured for estimating DNA synthetic activity. Refeeding increased the labeling index of the crypts (p less than 0.01) and the mucosal DNA synthesis (p less than 0.01) not only in the proximal colon but also in the excluded distal colon. The increase in labeling index was followed by a significant mitotic peak in both segments. These data indicate that direct intraluminal stimulation is not the only mechanism involved after feeding. There are other potent physiological stimulants of epithelial cell proliferation in the colon which are released postprandially.

Influence of a diverting colostomy on epithelial cell proliferation in the colon of rats

The effect of a transverse colostomy was compared to a sham operation and to transsection of the colon with reanastomosis in rats. The autoradiographic study after labeling with tritiated thymidine showed a significant decrease in proliferative activity at 5 days and at 3 weeks in the colonic segment distal to the colostomy. This observation was confirmed by the occurrence of mucosal atrophy and by a significant decrease in the mucosal DNA synthesis activity. It was concluded that the intraluminal presence of fecal bulk is an important factor in the maintenance of cell renewal in the colon of rats. Other factors seem, however, to be involved since a delayed but significant decrease in proliferative parameters was also observed proximal to the colostomy; no mucosal atrophy occurred in the latter segment.