A new percutaneously adjustable, thoracoscopically implantable, pulmonary artery banding: an experimental study

BACKGROUND

In patients who undergo left ventricular retraining, multiple reoperations are often necessary to adjust the pulmonary artery banding. The availability of a percutaneously adjustable band would be very useful.

METHODS

Ten lambs (10 to 25 kg) underwent pulmonary artery banding using a new device, 7 by thoracotomy and 3 by thoracoscopy. The possibility of percutaneously adjusting the band was evaluated immediately after operation in 10 animals and at 3 months in 8 animals.

RESULTS

One death occurred on the day of the procedure from displacement of the device and another death was from infection. Immediate hemodynamic studies proved the feasibility of increasing right ventricular afterload in a precise and reversible way. After 3 months the band could still be precisely loosened or tightened in all but 1 animal. Autopsy revealed that all the devices were in the correct position and no fibrosis or adhesions were present around the devices, and there was no residual stenosis noted on the pulmonary artery.

CONCLUSIONS

This new device may be a valuable alternative to the repeated pulmonary artery banding needed for ventricular preparation.

Pericarbon pericardial bioprosthesis: an experience based on the lessons of the past

BACKGROUND

The Pericarbon pericardial bioprosthesis, at the time of its creation, showed a breakthrough in terms of low calcification deposit rate, absence of valvular tears, and durability. The purpose of this study was to evaluate results after 10 years.

METHODS

From September 1988 to December 1997, 277 patients received a total of 287 Pericarbon pericardial valves. There were 224 (80.8%) isolated aortic valve replacements (AVR), 39 isolated mitral valve replacements (MVR), 1 tricuspid valve replacement, 3 pulmonary valve replacements, and 10 aortic and mitral valve replacements. The total cumulative follow-up was 1,221.42 patient-years (mean 4.9+/-2.6 years).

RESULTS

Overall hospital mortality was 10.1%. The overall patient survival at 10.8 years was 55.8%+/-4.2%, for AVR it was 60.0%+/-4.5%, and for MVR it was 46.5%+/-11.9%. The freedom from valve-related death for the overall population at 10.8 years was 98.0%+/-1.0%, for AVR 97.6%+/-1.1%, and for MVR 100%. The overall freedom from structural valve deterioration was 96.6%+/-2.4%, for AVR 96.1%+/-2.7%, and for MVR 100%. The overall freedom from embolic events was 96.0%+/-1.5%, for AVR 96.0%+/-1.6%, and for MVR 100%. The overall freedom from reoperation was 88.1%+/-3.8%, for AVR 89.9%+/-4.2%, and for MVR 80.6%+/-7.3%.

CONCLUSIONS

These results show that over a period of up to 10 years, the Pericarbon pericardial bioprosthesis is an excellent and safe valve substitute. Developing a detoxification process aimed at improving the biological behavior of the glutaraldehyde-tanned valve may increase those advantages.

Adult cardiac myocytes survive and remain excitable during long-term culture on synthetic supports

OBJECTIVE

Cardiomyocytes can be transplanted successfully into skeletal and cardiac muscle. Our goal was to determine the feasibility of grafting cardiomyocytes onto various synthetic supports to create an excitable and viable tissue for implantation.

METHODS

Adult rat cardiomyocytes were cultured over an 8-week period onto different substitutes, including human glutaraldehyde-treated pericardium (n = 3), equine glutaraldehyde-treated pericardium (n = 3), polytetrafluoroethylene (n = 8), Dacron polyester (n = 16), and Vicryl polyglactin (n = 8).

RESULTS

Only the cells seeded on the Dacron survived, with the synthetic fibers colonized at 8 weeks. On the other supports, the number of myocytes progressively decreased from the first week, with their density (number of cells per square millimeter) being, after 20 days, 17 +/- 2 on the polytetrafluoroethylene and 5 +/- 1 on the human or equine pericardium compared with 45 +/- 3 on the Dacron. After 8 weeks of culture on Dacron, the sarcomeric protein (sarcomeric alpha-actinin) was detected in all cells. In addition, the staining was regularly arranged and well aligned in a striated pattern. Spontaneous beating activity was obtained. Moreover, electrical stimulation of the cell preparation resulted in the generation of calcium transients, the frequency of which followed the frequency of the electrical stimulation.

CONCLUSIONS

These results suggest that adult cardiac myocytes remain viable and excitable during long-term culture on a 3-dimensional Dacron support, which might constitute a new synthetic cardiac tissue.

Ten-years' clinical experience with the Sorin Pericarbon valve

BACKGROUND AND AIM OF THE STUDY

The study aim was to evaluate 10 years' results obtained with the Pericarbon pericardial bioprosthesis.

METHODS

Between September 1988 and December 1997, 277 patients (mean age 75.8 +/- 8.5 years) received a total of 287 Pericarbon pericardial valves. Of these patients, 224 (80.8%) underwent single aortic valve replacement (AVR) and 39 single mitral valve replacement (MVR); one patient had a tricuspid valve replacement (TVR), three patients had a pulmonary valve replacement (PVR) and 10 had both aortic and mitral valve replacement (DVR). Associated cardiac procedures were performed in 86 patients (31.0%), mainly coronary artery bypass graft (n = 71). Mean patient follow up was 4.9 +/- 2.6 years; total cumulative follow up was 1,221.4 patient-years.

RESULTS

The overall hospital mortality rate was 10.1%. There were 50 late deaths (20.1%), four (1.6%) being valve-related. The patient survival rate at 10.8 years was 60.0 +/- 4.5% for AVR and 46.5 +/- 11.9% for MVR. Freedom from valve-related death at 10.8 years was 97.6 +/- 1.1% for AVR and 100% for MVR. Freedom from structural valve deterioration was 96.1 +/- 2.7% for AVR and 100% for MVR. Freedom from embolic events was 96.0 +/- 1.5% for AVR and 100% for MVR. In total, 16 patients needed reoperation, three for stenosis due to dystrophic calcification, six for endocarditis and seven for paravalvular leak. Freedom from reoperation was 89.9 +/- 4.2% for AVR and 80.6 +/- 7.3% for MVR.

CONCLUSION

These results show that, over a period of up to 10 years, the Pericarbon pericardial bioprosthesis constitutes an excellent and safe replacement valve.

"Swiss cheese" septal defects: surgical closure using a single patch with intermediate fixings

BACKGROUND

Residual ventricular septal defects and ventricular and septal dysfunctions are surgical drawbacks of "Swiss cheese" defects. We developed a technique that uses a single patch with intermediate fixings to cover the right side of the septum without producing a septal bulging, through a right atriotomy.

METHODS

Since April 1993, 5 children with "Swiss cheese" defects have been operated on using this procedure (mean age, 17 +/- 12 months). Three patients had associated lesions including tetralogy of Fallot, Taussig Bing heart, and mitral stenosis.

RESULTS

There have been no early or late deaths. The mean follow-up time is 29 +/- 18 months. All patients are asymptomatic. Echocardiography revealed either an intact septum (n = 4) or insignificant color jets at the apical portion of the septum (n = 1). The septal wall motion was preserved in 4 children and was hypokinetic in the fifth child.

CONCLUSIONS

This technique can be an additional tool to provide a secure closure of "Swiss cheese" defects even in the presence of associated cardiac lesions. Long-term consequences of this procedure on septal wall motion remain to be determined.

Surgical treatment of aortic root aneurysm related to Marfan syndrome in early childhood

The prognosis of Marfan syndrome in both adult and pediatric patients is primarily related to the cardiovascular complications. In infantile Marfan syndrome, although involvement of the mitral valve is the most frequently encountered cardiovascular lesion, the aortic root can be more worrisome because of its excessive dilatation, leading to aortic insufficiency or dissection. If the role of elective surgery is relatively well defined for adult patients, it is still debated during childhood. We report two patients, aged 22 months and 5 years, each presenting an aortic root aneurysm related to Marfan syndrome, and each treated with the Bentall procedure without specific age-related mortality or morbidity. These two patients experienced normal growth and were free of any complication for a follow-up period of 8 and 2 years, respectively. More than an absolute value of the aortic root dimension, it is the conjunction of the rate of progression of the aortic root dilatation, the degree and the duration of the aortic valve regurgitation, and its resulting left ventricular dysfunction that must be taken into consideration in choosing the surgical option.

Endoscopic saphenous vein harvesting versus 'open' technique. A prospective study

OBJECTIVE

Preparation of the great saphenous vein for coronary artery bypass grafts is usually performed through one or many cutaneous incisions. A technique of endoscopic harvesting is now available. An aim of the study was to compare both methods, prospectively.

METHODS

Sixty coronary artery bypass grafting patients were randomly assigned to two groups according to saphenous vein harvesting technique: 30 patients to group 1 -- open harvesting technique (OHT) and 30 patients to group 2 -- endoscopic harvesting technique (EHT). The results were assessed on the basis of (1) clinical outcome (hematomas, inflammations), (2) length of the cutaneous incisions compared to length of the segment of vein harvested, (3) time of harvesting, (4) postoperative pain.

RESULTS

Both groups were comparable in terms of: age, sex, diabetes, peripheral artery disease, site of harvesting, number of anastomoses, and length of the vein harvested. Both the length of the cutaneous incisions and the postoperative pain were decreased in the EHT group. Harvesting time was increased in the OHT group.

CONCLUSIONS

Endoscopic saphenous vein harvesting allows improved aesthetic aspect, less postoperative discomfort, with an increased time in harvesting in the beginning.

[Value of the spiral angio-scanner with three-dimensional reconstruction in the surgical strategy of unifocalization. Apropos of a case]

One of the difficulties of surgical treatment of pulmonary atresia with patent septum by unifocalisation resides in the accurate diagnosis of the different collateral vessels to the lung in order to optimise the surgical approach: anterior or posterolateral thoracotomy, and to determine the type of operation: one or two stages repair. Conventional angiography, even using different views, cannot always give an accurate representation of the anatomy of the different collateral vessels, especially their relationship to the bronchial structures. The authors report the contribution of spiral angioscanner with three dimensional reconstruction in the determination of the operative strategy of a case of pulmonary atresia with patent septum.

Videothoracoscopic surgical interruption of patent ductus arteriosus

A videothoracoscopic surgical technique for closure of patent ductus arteriosus in children is described. Only three ports of access are necessary to dissect the patent ductus arteriosus from the surrounding tissues and to apply the two titanium clips. The advantages given are the technique's low morbidity, lack of mortality, and reliable closure. We believe that the videothoracoscopic surgical approach is the technique of choice for patent ductus arteriosus closure in children.

Video-thoracoscopic surgical interruption of patent ductus arteriosus. Routine experience in 332 pediatric cases

OBJECTIVE

Pediatric video-assisted thoracic surgery closure of patent ductus arteriosus can now be performed on a routine basis. We review here our entire experience with this technique.

METHODS

Three hundred and thirty two consecutive patients underwent video-assisted closure of patent ductus arteriosus from September 1991 to September 1996. Indications were symptomatic ductus or failure of closure in older children. All complications were carefully noted, as well as intensive care unit stay, and operating room time.

RESULTS

Patients were divided in three age groups: less than 6 months (101 patients, 31%), 6-48 months (179 patients, 54%), greater than 48 months (52 patients, 16%). The mean weight was 12.6 kg (range 1.2-65 kg). Associated cardiac anomalies were atrial septal defect (3), ventricular septal defect (5), anomalous pulmonary venous return (1). Six patients had a residual shunt following video-assisted interruption. Five patients had successful immediate clip repositioning (three via video-assisted interruption, two via thoracotomy). One patient continued to have a small shunt, which is followed medically. Complications included recurrent laryngeal nerve dysfunction in six patients (1.8%) (five transient, one persistent). Mean operating time was 20 +/- 1.5 mn and hospital stay averaged 48 h (> 6 months), 72 h (< 6 months).

CONCLUSIONS

Interruption of patent ductus can be safely performed by video-assisted technique with minimal morbidity and no mortality. It can be performed in all age group with minimal hospital stay.

Bidirectional inferior vena cava-pulmonary artery shunt

BACKGROUND

Bidirectional superior vena cava-pulmonary shunt is widely used as an interim palliation for patients with univentricular hearts. Bidirectional inferior vena cava-pulmonary artery shunt, as an alternative approach of partial Fontan circulation, may offer the advantage of performing the complete Fontan circulation more easily due to the already constructed inferior vena cava lateral tunnel.

METHODS

We used bidirectional inferior vena cava-pulmonary artery shunt in 2 patients. Contraindications to a complete Fontan circulation were due to, respectively, a volume-overloaded systemic ventricle and an irregular pulmonary arterial tree.

RESULTS

Postoperative courses were uneventful. There were no significant pleural effusions. Transcutaneous oxygen saturations were 77% and 78%. Pulmonary-to-systemic blood flow ratios were 0.57 and 0.63. A complete Fontan circulation was safely performed 8 and 12 months later, without any "Fontan-related" complications.

CONCLUSIONS

Bidirectional inferior vena cava-pulmonary artery shunt can be useful in selected patients with univentricular hearts, although its place in the field of "partial Fontan operations" cannot be determined as yet.

Coronary artery revascularisation without extracorporeal circulation. Indications and results

OBJECTIVE

Coronary artery revascularisation without extracorporeal circulation is a technique which can be performed in selected patients in need of a coronary artery bypass graft.

METHODS

Consecutive patients (210) underwent coronary artery bypass graft without extracorporeal circulation. Indications were high risk patients, or single coronary artery lesion. To predict perioperative mortality, preoperative risk factors were reviewed, and Parsonnet score was calculated.

RESULTS

There were seven deaths (3.3%), and univariate analysis revealed greater age, NYHA, and poor ejection fraction to be the only predictors of early mortality. Perioperative myocardial infarction included 15 patients (7.1%), most of them seen in the multiple bypass group (10/39, 26%). Patients were divided into low risk (Parsonnet score < 15) 155 patients with two deaths (1.2%), and high risk (Parsonnet score > 15) 55 patients with five deaths (9%). Complete revascularisation was performed in the low risk group, while in the high risk only the symptomatic vessel was bypassed and other angiographic lesions treated with postoperative angioplasty (10 patients). A total of 12 patients developed early postoperative angina (5.7%), 9 presented an anastomosis dysfunction which was treated by angioplasty (5) and surgery (4), and 188 patients (85.7%) did not receive transfusions while 190 patients (90.4%) did not need postoperative inotropes. Length of stay, operating room time, and medical costs were all significantly reduced.

CONCLUSIONS

Myocardial revascularisation without extracorporeal circulation can be performed with a low operative mortality, and minimal morbidity only in patients undergoing single bypass revascularisation. It can also be performed as part of a multiple revascularisation strategy in association with angioplasty in high risks patients.

Calcified embolus of the left coronary ostia after aortic valve replacement

A patient with a left coronary calcified embolus causing acute myocardial dysfunction immediately after aortic valve replacement is described. Prompt diagnosis by transesophageal echocardiogram was made, which led to removal of the embolus and a subsequent satisfactory course.

Right anterolateral thoracotomy for repair of atrial septal defect

BACKGROUND

To procure a cosmetic incision in female patients, we performed operation on atrial septal defects through a right anterolateral thoracotomy.

METHODS

From 1984 to 1994, 80 female patients with a mean age of 24 +/- 13 years (ranging from 12 to 62 years) underwent right anterolateral thoracotomy for atrial septal defect repairs. Defects repaired included 62 ostium secundum, 12 sinus venosus, 2 low septal defect, and 4 ostium primum. The right iliac external artery was systematically used for arterial cannulation, through a cosmetic incision. Repairs were always performed under fibrillation, except in the 4 ostium primum defects, for which cardioplegia was used.

RESULTS

There was no operative or late mortality, and no morbidity directly related to the thoracotomy approach.

CONCLUSIONS

The right thoracotomy incision appears to be a safe and effective alternative to median sternotomy for repair of atrial septal defects.

[Techniques of correction of partial right abnormal pulmonary venous return associated with atrial septal defect]

Many techniques have been described for correcting partial right anomalous pulmonary venous drainage to avoid the possible complications of stenosis of the systemic or pulmonary venous return, residual shunt or arrhythmias. Between 1985 and 1994, 33 patients aged 1 to 69 years underwent repair of this malformation. The anomalous drainage was situated at the cavo-atrial junction or above in 25 cases and to the right atrium in 8 cases. Depending on the level of the drainage of the anomalous pulmonary veins, the size of the superior vena cava, the site of atrial septal defect and the age of the patient, 3 techniques were used: simple tunneling, tunneling with widening of the superior vena cava by a patch, tunneling with section of the superior vena cava and its transposition to the right atrium. There was no hospital mortality. Postoperative echocardiography showed a minimal residual shunt which regressed at the two months control examination. No cases of restriction of the systemic or pulmonary venous return were observed. Six patients developed arrhythmias during the hospital period. At the end of follow-up, all patients were asymptomatic without residual shunts or restriction of venous drainage. Persistent arrhythmias were observed in one case (3%). There were no differences in the results of the three techniques used. By using the most appropriate technique of repair for the anatomical form allows correction of this malformation with the minimal number of postoperative complications.

[Pulmonary arborization abnormalities in complex forms of pulmonary atresia with ventricular septal defect: unification, unifocalization and complete repair]

The presence of intrapulmonary arborization abnormalities in patients with pulmonary atresia and ventricular septal defect remains a therapeutic challenge. The aim of this study was to assess the value of procedures of pulmonary unifocalization, i.e. pulmonary unification, remodelling of the central pulmonary arteries and creation of an unifocal pulmonary blood supply, thereby resulting in complete repair. From october 1989 to october 1995, 27 unifocalization procedures were performed in 19 patients. The number of pulmonary segments dependant on non-communicating systemico-pulmonary collaterals was 14.7 +/- 5.4 per patient. The number of non-communicating systemico-pulmonary collaterals was 3.4 +/- 1.2 per patient. The Nakata index was 71 +/- 83 mm2/mm2. There were 3 deaths after an unifocalization procedure (mortality rate 15.8%). In 12 patients (63.2% of cases) a pulmonary arterial tree compatible with a complete repair was obtained. Eight complete repairs, with no mortality, following one or several pulmonary unifocalization procedures with a right to left ventricular systolic pressure ratio of 0.61 +/- 0.12 (range 0.4 to 0.75). Pulmonary unifocalization increases the recruitment of pulmonary segments and thereby the possibilities of complete correction in forms of pulmonary atresia with ventricular septal defect and arborization abnormalities of the pulmonary arterial tree.

Surgical treatment of diffuse supravalvular aortic stenosis

Diffuse supravalvular aortic stenosis can be treated by a variety of surgical approaches. In this case of severe diffuse supravalvular aortic stenosis in a child, we used the combination of an apicoaortic conduit followed 6 years later by aortic valve replacement, replacement of the ascending aorta and aortic arch, and an ascending to thoracic descending aorta bypass graft.

Bypass graft for complex forms of isthmic aortic coarctation in adults

BACKGROUND

Bypass grafting for complex forms of coarctation has been poorly documented as an alternative to decrease the high complication rate associated with anatomic repair.

METHODS

Between mid-1980 and the end of 1994, 16 patients underwent bypass grafting for complex forms of isthmic aortic coarctation. Age ranged from 11 to 49 years (mean age, 28.4 +/- 13 years). Indications were atypical anatomic forms of coarctation (n = 12) and reoperation after multiple or complicated previous coarctation repair (n = 4). Lateroisthmic bypass grafts were performed in 14 patients and ascending aorta-descending aorta bypass grafts in 2.

RESULTS

There was no hospital mortality. Morbidity consisted of postoperative paradoxical hypertension in 3 patients. There were no spinal cord complications. One death 10 years postoperatively was unrelated to the surgical technique. One patient successfully underwent ascending aorta-descending aorta bypass grafting for a false aneurysm 10 years after lateroisthmic grafting. All patients were asymptomatic and all grafts, patent after a mean follow-up of 5.7 +/- 4 years.

CONCLUSIONS

On the basis of these results, bypass grafting appears to be a safe alternative in this select group of patients. The lateroisthmic bypass graft is the procedure of first choice, and the ascending aorta-descending aorta bypass graft should be reserved for failure of previous lateroisthmic bypass grafting.

Valved conduit bypass for extensively calcified tricuspid valve stenosis

A case of calcified tricuspid valve stenosis resulting from a complication of ventriculoatrial shunt implantation is presented. Tricuspid valve repair or replacement was not possible because of the prohibitive risk of damaging the right atrioventricular junction and conductive pathways. This rare lesion was treated successfully by insertion of an external right atrial-right ventricular valved conduit. The role of echocardiography in the detection of such a lesion is emphasized and the etiologic and therapeutic aspects are discussed.

[Influence of anatomo-pathological involvement of the aorta on results of Bentall's operation]

The results of 51 patients undergoing the Bentall procedure for aneurysmal pathology of the ascending aorta during the last 10 years are analysed with respect to the nature of the pathology of the lesions of the arterial wall. The study population comprised 39 men and 12 women with a mean age of 47 +/- 17 years (range 2-76 years). They were divided into two groups, Group I (n = 38) with degenerative cystic medianecrosis, Group II (n = 13) with atheromatous lesions. The overall results were satisfactory with a hospital mortality of 3.9% and 5 and 10 year survival rates of 94 and 74% respectively. No difference in results was observed with respect to the anatomical site of the aneurysm, the presence of dissection or the technique used for repair. The results in degenerative lesions (Group I) were excellent but the accent should be placed on prevention to reduce the number of patients operated in a context of acute dissection. The presence of atheromatous lesions identifies a high risk group (Group II) due to advanced age, hypertension and associated vascular and coronary lesions. The hospital mortality in this group was 15.4% compared to almost nil when the aneurysmal pathology was due to degenerative lesions of the media. The extramortality of this group is directly related to the presence of atheromatous lesions (mesenteric infarction due to atheromatous embolism) and incites special attention to the mesenteric sphere in the postoperative period. The preoperative work-up should include transoesophageal echocardiography of the thoracic aortic wall, probably the source of the postoperative emboli.

[Cardiac transplantation for old congenital heart diseases after multiple surgery]

Of the 100 consecutive patients undergoing cardiac transplantation between January 1988 and October 1993, 4 patients had terminal cardiac failure related to congenital heart disease after multiple prior palliative procedures (transposition of the great arteries, N = 1, tricuspid atresia, N = 1, single ventricle, N = 2). The prior palliative or curative operations (average 3.75 procedures per patient) modified essentially the systemic venous return and the pulmonary arteries. The technique of "subtotal" cardiac transplantation enabled anatomical reconstruction without prosthetic material in all cases by extensive usage of the donor tissue. There was no hospital mortality. There were no specific postoperative complications. The long-term results were comparable to those of the rest of the transplanted population. Patients with congenital heart disease in a terminal condition should be considered as candidates for cardiac transplantation. The difficulties related to anatomical abnormalities caused by prior surgery may be overcome and should not be considered a contra-indication to transplantation, providing pulmonary arterial resistances are taken into consideration.

Technical modification for anastomosis of low-lying coronary ostia in Bentall procedure

Bentall procedure is not advisable when the origins of the coronary artery ostia cannot reach the composite valve graft at a satisfactory level for direct reimplantation. The other alternatives to coronary artery ostia reimplantation have some disadvantages. A technical modification of the Bentall procedure, successfully used in 3 patients and allowing direct coronary reimplantation without any tension on the suture line, is described.

Prevention of seroma formation after dissection of musculocutaneous flaps

Dissection of musculocutaneous flaps is uniformly followed by the formation of seroma if drains are not used. Drains can be colonized and form deep tissue infection if left in place for a long time. In this study we investigated whether talc poudrage could prevent the formation of seroma following dissection of the latissimus dorsi muscle in a canine model. Twelve mongrel dogs were randomized into two groups. Group 1 (n = 6) underwent dissection of the left latissimus dorsi muscle which was rotated as a pedicle flap into the left chest through a second intercostal space thoracotomy. The wound was closed in layers without drains. Group 2 (n = 6) had the same procedure, but before closure of the wound, USP talc was applied to the tissues. All animals received cefazolin (500 mg) Q8h for 48 hours perioperatively. Animals were followed for 1-5 months. Wounds with fluctuation were aspirated as many times as necessary and the amount of fluid was recorded. All Group 1 animals developed seromas, in contrast, only one animal in group 2 had a seroma. There was a significant difference in the amount of fluid aspirated for each animal between the two groups (280 +/- 80 in group 1 vs 25 +/- 25 ml in group 2, P < 0.05). The total amount of fluid drained in group 1 was 1730 ml, whereas only 150 ml was aspirated in group 2. Group 1 animals required a total of 11 aspirations to control seromas, in contrast, only one aspiration was needed in group 2. No abscess was identified at postmortem in either group. Based on the results of this study we conclude that talc poudrage can be safely used to minimize seroma formation after dissection of musculocutaneous flaps.

Pericardiotomy improves left ventricular compliance during sepsis-induced pulmonary artery hypertension

Sepsis-induced pulmonary artery hypertension (SIPAH) causes an increase in right ventricular (RV) afterload, dilatation of the RV, leftward shift of the interventricular septum (IVS), and therefore decreases left ventricular compliance (LVC). This study was designed to evaluate the role of pericardiotomy during SIPAH as an alternative to vasodilators (which cause a detrimental increase in shunt fraction) to improve LVC. Systemic and pulmonary hemodynamics, pulmonary function, RV, and LVC were acquired at baseline (BL), during SIPAH with closed pericardium (PAHCP) and after opening the pericardium (PAHOP). Systemic hemodynamics and pulmonary function did not change significantly during the experiment. The infusion of live bacteria induced a significant rise in mean pulmonary artery pressure from 16 +/- 5.3 at BL to 36.8 +/- 3.3 and 35.0 +/- 6.4 mm Hg during PAHCP and PAHOP, respectively, (P less than 0.05). Pulmonary vascular resistance index and right ventricular stroke work index (RVSWI) displayed a similar rise in response to SIPAH (P less than 0.05 vs BL). Pericardiotomy did not affect pulmonary hemodynamics or RVSWI. Right ventricular contractility did not increase following pulmonary hypertension while the pericardium was closed (440 +/- 78 vs 410 +/- 125, P less than 0.05); however, it rose, although not significantly, to 615 +/- 326 after pericardiotomy. RV time tension index displayed a rise during SIPAH with the pericardium intact and returned to baseline values after pericardiotomy; however, these changes were not significant. RVC did not change significantly throughout the experiment. In contrast, LVC decreased significantly after SIPAH and significantly improved after pericardiotomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Internal mammary coronary artery anastomosis by CO2 laser: an acute experimental study

This study was designed to determine the feasibility of anastomosing the internal mammary artery (IMA) and coronary artery with a carbon dioxide laser in a canine model. Twenty-two mongrel dogs were randomly assigned to two groups: group I (n = 11) underwent laser-assisted vascular anastomosis (LAVA) of the left IMA to the left anterior descending (LAD) coronary artery, whereas in group II (n = 11) the anastomosis was done with the conventional technique (handsewn). Laser methodology was used to micro-weld vessels utilizing a power of 200 mW with a spot size of 500 mu, producing an effective power density of 102 W/cm2 and energy fluence of 9,172 joules/cm2 in a continuous mode at a distance of 2 cm. The short-term patency rate, measured at 2 hours after completion of the anastomosis, was 100% in both groups. The time required to perform the LAVA in group I was significantly shorter than group II (6.27 +/- 0.47 vs 11.6 +/- 0.67 min, p less than 0.05). The mean anastomotic bursting pressure in group I was significantly lower compared to group II (348 +/- 8 vs 402 +/- 9 mmHg, p less than 0.05). Histologic evaluation of all vessels showed moderate thermal injury of the adventitia and media in the laser group. Scanning electron microscopy exhibited a smooth anastomotic area in group I, whereas endothelial and perianastomotic changes with multiple needle craters occurred in group II (conventional anastomosis).(ABSTRACT TRUNCATED AT 250 WORDS)