Corrective use of the 2.5-mm GFX stent for suboptimal angioplasty results in small coronary arteries

To evaluate the clinical efficacy of endoluminal stenting in the setting of percutaneous intervention for small coronary artery lesions, we reviewed our results on stenting with the 2.5-mm GFX stent (Arterial Vascular Engineering, Santa Rosa, CA) during an 18-month study period. A total of 120 patients with significant coronary artery disease in vessels </=2.6 mm were followed up clinically. Procedural success (defined as angiographic residual stenosis <20% without clinical complications) was obtained in 94% of cases. In-hospital complications were death (1%), non-Q-wave myocardial infarction (5%), and urgent repeat percutaneous intervention because of stent thrombosis (3%). During a mean follow-up of 9.8 months (range, 6-23 months), the following complications were noted: myocardial infarction (1%), clinical need for repeat intervention (13%) requiring repeat percutaneous treatment (12%) and surgical revascularization (1%). In conclusion, transcatheter application of a specifically designed stent for coronary artery disease in small vessels seems safe and efficient with a low incidence of adverse events during follow-up. Cathet. Cardiovasc. Intervent. 48:157-161, 1999.

[Cardiovascular disease in pregnancy]

There is a heterogeneous population of young women with cardiovascular disease contemplating pregnancy. Many of the conditions are rare and require teams with expertise in the management of such patients. A specific congenital or acquired cardiovascular anomaly and its physiology must be understood. The nature of prior surgical procedures and the residua and sequelae following therapy are essential to manage a pregnant woman with cardiovascular disease. Physiologic changes during pregnancy and after delivery must be known. Counseling includes maternal and fetal risk stratification and genetic counseling regarding inherited disorders. The outcome of pregnancy is favourable in many women with good functional class. These patients can be reassured. A multidisciplinary approach may be crucial to manage this population during pregnancy, labour, delivery and in the postpartum period to avoid serious maternal and fetal complications. Women with intermediate and high risk pregnancy must be followed and managed in a high risk pregnancy unit and a team from obstetricians, cardiologists, anesthetists, pediatricians, neonatologists and cardiac surgeons who are skilled in high risk pregnancies. Vaginal delivery is the method of choice in many women (class 1 woman) and cesarean section is seldom a cardiac indication. Contraindications for pregnancy are: poor maternal functional class, poor ventricular function, severe cyanosis without pulmonary hypertension (oxygen saturation < or = 85%), pulmonary vascular disease, severe mitral stenosis, severe left ventricular outflow tract obstruction, Marfan syndrome with aortic dilatation (> 40 mm) and aortic valve involvement (moderate to severe aortic regurgitation), symptomatic hypertrophic obstructive cardiomyopathy. Preconception counseling must be offered if unfavourable outcome is likely. Tubal ligation is probably the safest and most appropriate method of sterilization if there is a high risk pregnancy.

Composite graft replacement of the aortic root: long-term results, incidence of reoperations

BACKGROUND

Long-term results after composite graft replacement of the aortic root may depend on the insertion technique.

METHODS

181 consecutive patients (mean age 53 years; 153 men) operated on between 1983 and 1993 were studied. Indications for surgery were annuloaortic ectasia (n=98), acute aortic dissection (n = 46), other indications (n = 12), and various indications after previous aortic valve replacement (n = 25). Mean follow-up was 28 months. The open-button technique was performed in 74 patients (41 %) and the Bentall inclusion technique in 107 patients (59%), with a Cabrol shunt to the right atrium in 16 patients.

RESULTS

Overall survival was 75% after 7 years, significantly decreased in acute aortic dissection (p = 0.0019) and without difference between the two surgical techniques (p = 0.3166). Reoperation-free survival was 69% at 7 years and significantly decreased after acute dissection (p = 0.0421 ). Pseudoaneurysm formation only occurred in 3 patients operated with the Bentall technique not including a Cabrol shunt.

CONCLUSIONS

Long-term results are satisfactory. In acute aortic dissection survival is decreased and late reoperations more frequent. The open technique is safe in non-dissection and in acute dissection and avoids pseudoaneurysm formation. The Bentall technique combined with Cabrol shunt is indicated if there is a high risk of hemorrhage. Long-term monitoring of the aorta is mandatory in patients with acute dissection and/or Marfan disease.

Extended follow-up after atrial repair for transposition of the great arteries: a younger age at surgery improves late survival

BACKGROUND

Surgical treatment for transposition of the great arteries (TGA) usually involves anatomic repair, although atrial repair is used in cases with special coronary artery patterns.

METHODS

Records of all 239 patients surviving at least 30 days after atrial correction of TGA between 1962 and 1987 at the University Hospital in Zurich were reviewed. The mean length of follow-up time was 13.7 years (median 14.9 years; range from 0.05 to 30.1 years). The average age at surgery was 45.7 months (range from 7 days to 24.4 years). One hundred twenty-one patients had a simple TGA, whereas the remaining 118 had a complex TGA.

RESULTS

The surviving patients were in NYHA class I at time of follow-up. The most common reasons for death were systemic right ventricular dysfunction and sudden rhythm disturbances. There was a major risk for late cardiac event in patients over 3 years old at operation (p = 0.02) and also in patients with complex TGA (p = 0.03). However, date of surgery, previous surgery, or the postoperative requirement for a pacemaker did not greatly affect late cardiac mortality.

CONCLUSIONS

Although the procedure of choice for TGA is the arterial switch operation, the promising findings of the current long-term study, which reports the longest follow-up to date, indicate that the atrial switch operation is a good alternative procedure for the rare cases where the use of arterial switch procedures is limited.

Five-year outcome in patients with isolated proximal left anterior descending coronary artery stenosis treated by angioplasty or left internal mammary artery grafting. A prospective trial

BACKGROUND

Percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass surgery (CABG) improve the clinical status of patients with isolated proximal left anterior descending coronary artery stenosis. At 2 years, only additional revascularization was more frequently required after PTCA.

METHODS AND RESULTS

We monitored 134 patients randomized to PTCA (n=68) or CABG (n=66) for </=5 years. End points were death, myocardial infarction, need for additional revascularization, clinical status, and medical treatment. At 5 years, 6 patients (9%) had died in the PTCA group versus 2 (3%) in the CABG group (P=0.12). One patient in each group died of a cardiac cause. Myocardial infarction was more frequent after PTCA (15% versus 4%; P=0.0001), but Q-wave infarction was not (6% in the PTCA group versus 3% in the CABG group; P=0.8). Additional revascularization was required in 38% of patients in the PTCA group versus 9% in the CABG group (P=0.0001). Functional status was comparable, with 6% of patients after PTCA and 3% after CABG in functional class III or IV. Finally, after PTCA or CABG, 62% and 91% of patients, respectively, were free of events (P=0.0001).

CONCLUSIONS

The 5-year prognosis of patients with isolated proximal left anterior descending coronary artery stenosis is good. Both PTCA and CABG improve clinical status, but revascularization was needed more frequently after PTCA. There is an excess incidence of non-Q-wave myocardial infarction in the PTCA group that does not affect the vital or symptomatic outcome.

Immobility as a major cause of bone remodeling in residents of a long-stay geriatric ward

Residents of a long-stay geriatric ward at the University Hospital Basel were included in a study to investigate the effects of hypovitaminosis D and immobility. All 91 women (mean age 82.5 years) and 92 men (mean age 78.7 years) were enrolled in the study. Measurements included bone resorption, as measured by urinary deoxypyridinoline (dpd), serum 25-hydroxyvitamin D (25OHD), serum intact parathyroid hormone (iPTH), and their correlations with a four grade mobility score. Mobility score reflected the degree of weight bearing, ranging from walking independently to primarily bed bound. In 86% of all residents, serum 25OHD levels were below the normal limit of 12 ng/ml. Secondary hyperparathyroidism (HPT) was detected in 24% of all patients, using 55 pg/ml as the upper limit for serum iPTH. No significant correlation was found between urinary dpd and serum 25OHD or serum iPTH. Mobility index and both urinary dpd (f: P = 0.001, r = 0.37; m: P < 0.0001, r = 0.47) and serum calcium (female: P = 0.007, r = 0.28; male: P = 0.02, r = 0.24) were positively related. In institutionalized elderly people with a high prevalence of vitamin D deficiency serum intact PTH levels did not correlate with bone resorption as measured by urinary deoxypyridinolin. However, more immobile subjects had significantly higher excretion rates for urinary dpd and higher serum calcium levels. Our results suggest that in elderly people immobility may contribute to bone loss that might preempt the development of secondary HPT through elevation of serum calcium.

Differentiation-related expression of the Thomsen-Friedenreich glycotope in developing human lung and in lung carcinoma: lack of association with malignancy

BACKGROUND

It has been proposed that the Thomsen-Friedenreich glycotope represents a general carcinoma-associated antigen and a candidate for the development of a tumor vaccine. However, the expression of the unmasked and masked (sialylated) forms in lung carcinomas, as well as in developing and adult human lung, has not been documented sufficiently.

METHODS

Sections from 82 lung carcinomas, including squamous cell carcinomas, adenocarcinomas, and large cell and small cell carcinomas, as well as sections of developing and adult human lung were studied using the lectin amaranthin and a monoclonal antibody.

RESULTS

All lung carcinomas but one bronchiolo-alveolar carcinoma were unreactive for the Thomsen-Friedenreich glycotope, whereas its sialylated form was detectable in well-differentiated squamous cell carcinomas and adenocarcinomas, including bronchiolo-alveolar carcinomas. Both unmasked and masked Thomsen-Friedenreich glycotopes were undetectable in large cell and small cell lung carcinomas. In all developmental stages of lung, the Thomsen-Friedenreich glycotope was expressed only in epithelia of the most peripheral parts of the bronchial tree, whereas its sialylated form was expressed in epithelia of all parts of the bronchial tree. In adult lung, the Thomsen-Friedenreich glycotope was expressed in pneumocytes, whereas its sialylated form was expressed ubiquitously in all epithelia.

CONCLUSIONS

The Thomsen-Friedenreich glycotope in human lung represents a differentiation antigen, rather than a carcinoma-associated antigen. The sialylated form is expressed constitutively in both developing and adult lung and well-differentiated lung carcinomas. Thus, the Thomsen-Friedenreich glycotope is of limited value in the diagnosis of lung carcinoma, and there is no rationale for a Thomsen-Friedenreich glycotope-based immunotherapy for patients with this disease.

Conservative treatment of the aortic root in acute type A dissection

OBJECTIVE

In acute type A dissection long-term results of conservative aortic root surgery were compared with the outcome of primary valve and/or root replacement.

METHODS

Between 1985 and 1995, 199 patients (mean age 59 years, 154 men) were operated on. The aortic root was involved in the dissection process and valve incompetence of varying degree was present without exception. Replacement of a proximal aortic segment was standard procedure in all patients. The aortic valve was preserved in 126 patients: commissural suture resuspension (12 patients), root reconstruction with GRF-glue (gelatine-resorcin-formaldehyde/glutaraldehyde-glue) (114 patients). Valve replacement was performed in 73 patients (50 composite grafts, 23 valve prostheses with separate supracoronary grafts). Preoperative risk factors (valve replacement vs. preservation): coronary artery disease (11 vs. 8%, NS), tamponade (18 vs. 17%, NS), unstable hemodynamics (22 vs. 15%, NS), renal failure (4 vs. 6%, NS), neurologic disorder (19 vs. 32%, NS).

RESULTS

The overall early mortality was 23.6% (47/199 patients) and increased after commissural suture resuspension compared with GRF-glue reconstruction (P = NS). Parameters of the early postoperative period did not differ between conservative treatment and root/valve replacement: low cardiac output, 34 versus 38% (P = NS); myocardial infarction, 10 versus 11% (P = NS); hemorrhage, 25 versus 23% (P = NS); duration of intensive care (P = NS). Survival was 61% after 8 years without difference between the two principal treatment groups (P = NS) and between the two conservative subgroups (P = NS). At 2 years, GRF-glue reconstruction had an increased freedom from reoperation on the aortic root (92 vs. 70%, P = 0.0253) and event free survival (77 vs. 41%, P = 0.0224) compared with suture resuspension. Commissural suture resuspension was an independent, significant predictor for reoperation (P = 0.0221, relative risk = 4.7130).

CONCLUSION

Surgery for acute type A dissection still carries a considerable early risk. Preservation of the aortic root is safe in the absence of Marfan or annuloaortic ectasia, but a certain incidence of reoperations on the aortic valve and the aortic root has to be accepted. Root reconstruction using GRF-glue is the method of choice and is superior to suture resuspension, with a significantly better reoperation-free and event-free survival.

Bronchiolitis obliterans organizing pneumonia associated with polymyalgia rheumatica

The association of bronchiolitis obliterans organizing pneumonia (BOOP) with polymyalgia rheumatica is rare, and only one case has previously been described. This study reports on the case of an 80 yr-old male who presented with malaise, nonproductive cough and exertional dyspnoea for several weeks, along with a history of bilateral shoulder and pelvic girdle pain of several months' duration. The chest radiograph revealed a pneumonic infiltrate in the right lower lobe, which was unresponsive to antibiotics. Bronchoscopy, bronchoalveolar lavage and a transbronchial lung biopsy established the diagnosis of BOOP. The patient improved consistently on steroids. As in other connective diseases, organizing pneumonia may be one of the early manifestations of polymyalgia rheumatica.

Congenital subaortic stenosis by accessory mitral valve tissue, recognition and management

Accessory mitral valve tissue as the single cause for left ventricular outflow tract obstruction is a very rare cardiac malformation in normally connected hearts. We report a case in which this condition was present as single cause for left ventricular outflow tract obstruction. The surgical technique is described and a review of the literature presented.

Tissue engineering in cardiovascular surgery: MTT, a rapid and reliable quantitative method to assess the optimal human cell seeding on polymeric meshes

OBJECTIVE

Currently used valve substitutes for valve replacement have certain disadvantages that limit their long-term benefits such as poor durability, risks of infection, thromboembolism or rejection. A tissue engineered autologous valve composed of living tissue is expected to overcome these shortcomings with natural existing biological mechanisms for growth, repair, remodeling and development. The aim of the study was to improve cell seeding methods for developing tissue-engineered valve tissue.

METHODS

Human aortic myofibroblasts were seeded on polyglycolic acid (PGA) meshes. Cell attachment and growth of myofibroblasts on the PGA scaffolds with different seeding intervals were compared to determine an optimal seeding interval. In addition, scanning electron microscopy study of the seeded meshes was also performed to document tissue development.

RESULTS

There was a direct correlation between cell numbers assessed by direct counting and MTT(3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltertra-zoliu m bromide) assay. Both attach rate and cell growth seeded on meshes with long intervals (24 and 36 h) were significantly higher than those seeded with short intervals (2 and 12 h) (P<0.01), there was no significant difference between 24- and 36-h seeding interval. Scanning electron microscopy also documented more cell attachment with long seeding intervals resulting in a more solid tissue like structure.

CONCLUSION

It is feasible to use human aortic myofibroblasts to develop a new functional tissue in vitro. Twenty-four hours is an optimal seeding interval for seeding human aortic myofibroblasts on PGA scaffolds and MTT test is a rapid and reliable quantitative method to assess the optimal human cell seeding on polymeric meshes.

High-resolution intravascular magnetic resonance imaging: monitoring of plaque formation in heritable hyperlipidemic rabbits

BACKGROUND

The individual makeup of atherosclerotic plaque has been identified as a dominant prognostic factor. With the use of an intravascular magnetic resonance (MR) catheter coil, we evaluated the effectiveness of high-resolution MR in the study of the development of atherosclerotic lesions in heritable hyperlipidemic rabbits.

METHODS AND RESULTS

Sixteen hyperlipidemic rabbits were investigated at the ages of 6, 12, 24, and 36 months. The aorta was studied with digital subtraction angiography and high-resolution MR with the use of a surface coil and an intravascular coil that consisted of a single-loop copper wire integrated in a 5F balloon catheter. Images were correlated with histological sections regarding wall thickness, plaque area, and plaque components. Digital subtraction angiography revealed no abnormalities in the 6- and 12-month-old rabbits and only mild stenoses in the 24- and 36-month-old rabbits. High-resolution imaging with surface coils resulted in an in-plane resolution of 234x468 microm. Delineation of the vessel wall was not possible in younger rabbits and correlated only poorly with microscopic measurements in the 36-month-old rabbits. Intravascular images achieved an in-plane resolution of 117x156 microm. Increasing thickness of the aortic wall and plaque area was observed with increasing age. In the 24- and 36-month-old animals, calcification could be differentiated from fibrous and fatty tissue on the basis of the T2-fast spin echo images, as confirmed by histological correlation.

CONCLUSIONS

Atherosclerotic evolution of hyperlipidemic rabbits can be monitored with high-resolution intravascular MR imaging. Image quality is sufficient to determine wall thickness and plaque area and to differentiate plaque components.

Pregnancy after atrial repair for transposition of the great arteries

OBJECTIVE

To investigate the risk of pregnancy in patients with transposition of the great arteries (TGA) who have undergone atrial repair.

DESIGN

Retrospective analysis (1962-94) of 342 TGA patients who underwent atrial repair. Of 231 known late survivors, 48 were women over 18 years old who were interviewed about possible reproductive plans and previous pregnancies. As a control, comparison was made with data of 57 500 women (mean age 26 years) obtained from the Swiss Statistical Bank in Bern.

RESULTS

Mean follow up was 13.7 years; 66% remained asymptomatic, 29% had mild to moderate cardiac symptoms, and 5% suffered from severe cardiac symptoms (New York Heart Association grade III-IV). Thirty six of the 48 women wished to bear children and, to date, there have been 10 live births, two spontaneous first trimester abortions, and one induced abortion at 16 weeks. During pregnancy there was one case of cardiac deterioration and two cases of pneumonia. There was no evidence of congenital heart disease in the children.

CONCLUSIONS

In this relatively small series the completion of pregnancy in women with TGA who had undergone atrial repair and who had normal functional cardiac status was uncomplicated

Hemodynamic properties of the hemopump HP14

BACKGROUND

The Hemopump HP14 is a catheter-mounted, transvalvular, left ventricular assist device intended for femoral percutaneous insertion. The pump was developed for patients with postoperative or postinterventional low cardiac output and for CABG surgery on the beating heart. Little is known about the effect of afterload and hematocrit on the pump performance.

METHODS

The influence of hematocrit and afterload on the pump flow was tested using an in vitro model filled with heparinized bovine blood. Regression analysis of the pump flow with respect to three hematocrit values (20%, 30%, 40%) and ten afterload levels (30 mmHg-120 mmHg in 10 mmHg increments) was performed for all pump speed levels (n = 7).

RESULTS

At all pump speed levels reduction of afterload and hematocrit were significant predictors for increasing pump flow (p<0.001). For hematocrit values between 40% and 20% and highest pump speed, mean pump flow at lowest afterload ranged between 2.34 and 2.53 L/min; and at highest afterload between 1.31 and 1.53 L/min. For speed level 1, afterload of 120 mmHg and hematocrit of 40% there was a maximal retrograde flow of 230+/-35 ml/min.

CONCLUSIONS

Pump performance is significantly improved by both afterload and hematocrit reduction. In the weaning phase and during the removal of the device, the pump should run at a speed level of at least three to prevent retrograde flow in the pump. Estimates for pump flow in vivo can be extrapolated from our diagrams. Our results show that the Hemopump HP14 is a valuable alternative to intra-aortic balloon counterpulsation.

Optimized performance of the Abiomed BVS 5000: adjustment of the pump height based on Doppler control of the flow pattern

The Abiomed BVS 5000 is an automatic volume-driven paracorporeal pulsatile assist device providing left, right or biventricular support. The paracorporeal position allows optical adjustment of filling volumes of the device, which determines the output of the system. A procedure to adjust for maximal stable flow has not yet been established. In vitro measurements have been performed to assess the flow and pressure characteristics of the Abiomed BVS 5000 by raising the preload in 5 mmHg steps before running the system. Doppler probes were placed at the inflow and outflow lines of the pump. After setting the afterload at 80 mmHg the assist device was started. Two measurements were performed to find optimal flow (based on Doppler control and optical adjustment). (1) By Doppler control a stable flow pattern was found at a preload of 25 mmHg with a mean atrial pressure of 5 mmHg and a mean flow of 5.3 +/- 0.7 l/min (mean +/- standard deviation) at the inflow and outflow sites (the console flow was 4.8 +/- 0.4 l/min with a frequency of 61.8 +/- 2.0 l/min). (2) Optical adjustment of the pump height gave rise to a preload of 35 mmHg where we recorded a maximal atrial pressure of 107 +/- 5.8 mmHg, a maximal retrograde flow of -4.3 +/- 1.2 l/min at the inflow and -1.2 +/- 0.4 l/min at the outflow site. The mean flow at the inflow and outflow sites was 5.1 +/- 0.5 l/min (the console flow was 4.6 +/- 0.3 l/min with a frequency of 59.6 +/- 2.6 Hz). At an initial afterload of 60 and 40 mmHg the system showed the same qualitative behaviour, but the results were less accurate. Optical adjustment of the pump height may result in an atrioventricular valve insufficiency with undetected retrograde flow and high atrial pressures. We conclude that a Doppler flow probe must be placed at the inflow site to guarantee maximal stable flow.

[Percutaneous versus surgical revascularization of isolated lesions of the proximal anterior interventricular artery. Five-year follow-up of a prospective randomized study]

The authors report the results of 5 years follow-up of 134 patients who benefited from percutaneous transluminal coronary angioplasty 5PTCA) or surgical intervention with implantation of the internal mammary artery as treatment of an isolated lesions of the proximal left anterior descending artery with normal left ventricular function. Sixty-eight patients underwent PTCA (group 1) and 66 had surgical bypass (group 2). The demographic data of the two groups was comparable. The incidence of the following events was analysed: death, myocardial infarction, indication for further revascularisation and functional class. At 5 years, the global mortality was 6% (8% in group 1 and 2% in group 2) but cardiac mortality was only 1% (1 patient in each group). The cumulative incidence of myocardial infarction was higher after angioplasty (15% vs 5%) but was mainly related to acute occlusions or acute coronary syndromes during angioplasty. However, the incidence of Q wave infarction was similar in the two groups. During follow-up, 32 patients (26 in group 1 and 6 in group 2) required one or more additional revascularisation procedures of the left anterior descending or of another artery. The proportion of asymptomatic patients at 5 years was high and similar in both groups. Finally, the proportion of patients without events during follow-up was 56% in group 1 and 86% in group 2. Despite the risk of restenosis and reoperation associated with angioplasty, this technique is an acceptable therapeutic alternative to surgical revascularisation in patients with isolated stenosis of the left anterior descending artery. Therefore, the therapeutic decision depends on the individual case, the availability of treatment and the patient's preference during consultation.

CT appearances of hepatic involvement in systemic varicella-zoster

In a patient suffering from T-cell non-Hodgkin's lymphoma and systemic varicella-zoster, contrast enhanced CT showed multiple hypodense nodular lesions in the liver which corresponded to areas of focal liver necrosis. This appearance on CT may be characteristic of varicella-zoster involvement of the liver.

[Minimally invasive surgery for coronary disease: a new alternative]

To avoid the inflammatory syndrome generated by cardiopulmonary bypass, a new surgical technique, minimal invasive direct coronary artery bypass (MIDCAB), has been developed. An anastomosis is performed between the left internal mammary artery (LIMA) and the left anterior descending artery (LAD) on a beating heart, through a limited anterior thoracotomy. We describe our experience with this technique. Ten consecutive patients underwent a MIDCAB procedure. (9 males, age 65.9 +/- 9 years). There were 8 bypasses of the LIMA on the LAD, one bilateral mammary bypass on the LAD and the right coronary artery, and one conversion to a standard sternotomy with CPB for a saphenous vein bypass on the LAD because of injury to the LIMA (2nd case). There was one redo for haemostasis of the mammary artery bed (3rd case). The first 3 patients required postoperative blood transfusion. From the 4th operation onwards, with the introduction of new instrumentation which was better adapted to the narrowness of the surgical field, there were no further surgical complications. During the follow-up (mean 5 months; range 2-9), no patient suffered anginal recurrence. With the improvement of instrumentation, the MIDCAB technique offers satisfactory short- and mid-term results, while avoiding CPB with its adverse effects. Lastly, the cosmetic result is far better than with the conventional procedure.

[The significance of endothelial adhesion molecules in heart surgery]

Myocardial ischemia and reperfusion is a common event in cardiovascular surgery patients. The endothelium has been shown to play a key role in the injury suffered after ischemia and reperfusion. When endothelial cells became hypoxic followed by reoxygenation they become activated to express endothelial adhesion molecules followed by the migration of neutrophils into the tissue. These changes may contribute to the early postoperatively myocardial dysfunction. An increased understanding of the interaction between leukocytes and endothelium may allow to develop new therapies in future.

Tissue engineering: a new approach in cardiovascular surgery--seeding of human fibroblasts on resorbable mesh

INTRODUCTION

In tissue engineering the material properties of synthetic compounds are manipulated to enable delivery of dissociated cells onto a scaffold in a manner that will result in in vitro formation of new functional tissue. The seeding of human fibroblasts on resorbable mesh is a precondition of a successful creation of human tissue such as autologous cardiac valves.

MATERIAL AND METHODS

Polymeric scaffolds (n = 12) composed of polyglycolic acid (PGA) with a fiber diameter of 12-15 mm and a polymer density of 70 mg/ml were used as square sheets of 0.3 x 1 x 1 cm. Fibroblasts (passage 5), harvested from human foreskin, were seeded (3.4 x 10(6)) and cultured over a 3 week period on a PGA mesh.

RESULTS

Microscopic examination of the seeded mesh demonstrated that the human fibroblasts were attached to the polymeric fibers and had begun to spread out and to divide. Electron microscopy showed a continuous distribution and formation of the cells throughout the "polymeric architecture". Spotlike hydrolysis of PGA fibers was observed. After 3 weeks the seeded scaffolds resembled a solid sheet of tissue.

CONCLUSION

These preliminary results, successful seeding of human fibroblasts on a PGA mesh, represent a first basic step on the way to construct human tissue such as autologous cardiac valves and demonstrate that tissue engineering might be a promising new device in therapy of cardiovascular disease.

[Long-term follow-up after implantation of a coronary endoprosthesis]

The authors analysed the long-term clinical and angiographic follow-up of patients after coronary stenting for the treatment of coronary stenosis of a native artery or vein graft.

BACKGROUND

The need for revascularization at 6 months and the restenosis rate were decreased after coronary stenting, compared to the conventional percutaneous angioplasty. This benefit appears to persist in the longer term.

METHOD

The incidence of major clinical and angiographic complications was evaluated in 129 patients with a minimum follow-up of 3 years.

RESULTS

At 6 months, 20% of patients presented a major clinical complication and restenosis was documented in 20% of cases. In the long-term, a major cardiac event was observed in 49% of cases (death: 16%, infarction: 5%, coronary artery bypass graft: 12% and another angioplasty: 16%). Patients treated by stenting during coronary artery bypass graft had a significantly lower survival (60% versus 88%), and a higher incidence of major clinical complications (55% versus 18%), and a higher stent revascularization rate (41% versus 16%).

CONCLUSION

The late stent revascularization rate was low. Overall survival was significantly higher in patients treated for a native vessel than in those treated for a coronary artery bypass graft. The complication rate and stent revascularization rate were also significantly lower.

Endoluminal vessel reconstruction by stent placement in patients with obstructive coronary artery disease who are poor surgical candidates

OBJECTIVE

To investigate the safety and efficacy of endoluminal vessel reconstruction by intracoronary stenting in patients with single or multivessel disease who have been turned down for surgical revascularisation.

DESIGN

An observational, single centre trial of consecutive patients being followed up clinically.

SETTING

Tertiary referral centre.

PATIENTS

43 patients treated between 1995 and 1996 with a clinical follow up period of at least six months.

MAIN OUTCOME MEASURES

Acute procedural success following intervention (defined as a residual stenosis of < 30% with normal antegrade flow and without acute clinical complications); major adverse clinical events (death, myocardial infarction, repeat intervention, clinical restenosis); and functional status during follow up.

RESULTS

Acute procedural success was achieved in 39 patients. Failures resulted from a refractory no reflow phenomenon with Q wave myocardial infarction (two patients), and from subacute stent thrombosis (one patient) and saphenous vein graft rupture at stent site (one patient), both manifesting by non-Q wave myocardial infarction. During a follow up period of 17 (8) months (mean (SD)), three of these patients died. Clinical restenosis was treated by repeat percutaneous intervention in 11 patients, while 28 patients remained asymptomatic. On a Kaplan-Meier estimate, the proportion of patients without adverse clinical events at two years was 65%.

CONCLUSIONS

Percutaneous reconstruction of diseased coronary arteries in patients with single or multivessel disease turned down for surgical revascularisation may be considered as a valuable treatment option. On follow up, more events seem to be encountered than after elective de novo stenting of discrete coronary lesions. This is probably related to higher clinical restenosis rates.