Pleural opening impairs respiratory system compliance and resistance in off-pump coronary artery bypass grafting.

AIM: This study evaluated the effect of pleurotomy on respiratory system compliance and resistance in off-pump coronary artery bypass (OPCAB) using the left internal thoracic artery (LITA). METHODS: Thirty-two patients were prospectively allocated into two groups: OP group (n = 16 patients with open left pleural cavity); IP group (N.=16 patients with intact pleural cavity). Static and dynamic lung compliance and total respiratory system resistance calculation were recorded at anesthesia induction (before chest opening) and immediately after chest closure. RESULTS: Static lung compliance values significantly decreased after chest closure in both groups (P < 0.0001), but the OP group had a significantly greater decline (P = 0.0007). Dynamic lung compliance decreased in either groups after chest closure (P < 0.0001), however, no significant difference was found between groups (P = 0.228). Total respiratory system resistance increased in both groups (P < 0.05), however the OP group had a higher increase (P = 0.0005). Orotracheal intubation time (P = 0.041) and hospital stay (P = 0.0004) were higher in the OP group. CONCLUSION: Pleura opening and need of chest tube insertion induced significant reduction in static lung compliance and increase in total respiratory system resistance, furthermore contributing to impair pulmonary dysfunction in the early postoperative period after OPCAB.

Percutaneous balloon mitral valvuloplasty in comparison with open mitral valve commissurotomy for mitral stenosis during pregnancy.

OBJECTIVES: We sought to compare the maternal and fetal outcomes of patients with severe mitral stenosis submitted to percutaneous balloon dilation versus open mitral valve commissurotomy (MVC) during pregnancy. BACKGROUND: Heart failure in patients with mitral stenosis complicating pregnancy is a common problem in developing countries. Since 1984, percutaneous dilation of the mitral valve using a balloon catheter has become a therapeutic alternative to open heart surgery. Although the efficacy of percutaneous mitral valve balloon dilation is well established, its results have never before been compared with the results of commissurotomy during pregnancy. METHODS: We compared the clinical and obstetric complications in 45 women who were treated with percutaneous mitral valve balloon dilation (group I, n = 21; from 1990 to 1995) or open MVC (group II, n = 24; from 1985 to 1990) for severe heart failure due to mitral stenosis during pregnancy. RESULTS: In our study, percutaneous balloon dilation of the mitral valve had a success rate of 95% (Gorlin formula) and 90.5% (echocardiographic "pressure half-time" method), as demonstrated by the final mitral valve area achieved. This improvement was followed by a marked decrease in the mitral valve gradient, left atrial pressure and mean pulmonary artery pressure. Patients in both groups had similar improvements in symptoms. Patients who underwent percutaneous balloon dilation had significantly fewer fetal complications, with a reduction in fetal and neonatal mortality (1 death in group I vs. 8 in group II, p = 0.025). CONCLUSIONS: Percutaneous balloon mitral valvuloplasty is safe and effective and appears to be preferable for the fetus, compared with open MVC during pregnancy.

Surgical treatment of endomyocardial fibrosis.

Thirty patients with endomyocardial fibrosis were submitted to endocardial decortication and atrioventricular valve replacement between December, 1977, and October, 1981. There were 26 female and four male patients, ranging in age from 14 to 48 years (mean 32). Thirteen patients had biventricular disease, 14 had the right-sided form, and three had endomyocardial fibrosis confined to the left ventricle. All were in Functional Class III or IV (New York Heart Association classification). The hospital mortality was 20% (six cases). Among the survivors (mean follow-up 13 months), 23 of 24 were improved clinically. Postoperative hemodynamic and angiographic studies were performed in 15 patients. Two (6.6%) have definitive atrioventricular heart block. There were five (16.6%) late deaths. Operation for endomyocardial fibrosis should be considered a palliative procedure. Possible limitations include the need for a valve prosthesis, cardiac conduction disturbances secondary to endocardiectomy of the right ventricle, and the possibility of recurrence of the endocardial fibrosis. However, at present, operation seems to be the treatment of choice for this condition because (1) endomyocardial fibrosis is characterized by a grave prognosis and medical therapy is ineffective; (2) endomyocardial fibrosis is a disease in which only the heart is affected, lesions in other organs being the result of passive congestion; (3) systolic performance of the heart is usually only slightly depressed; and (4) the surgical procedure is easily performed, so that the mortality is acceptable.

Chagas' disease reactivation after heart transplantation: efficacy of allopurinol treatment.

BACKGROUND: Chagas' disease is a parasitic infection that provokes a severe form of dilated cardiomyopathy. In the initial experience with heart transplantation with Chagas' disease, a high rate of acute reactivation has been reported. Although benzinidazole and nifurtimox are effective in the treatment of reactivation or of the acute phase of the disease they are associated with important adverse effects. Allopurinol has substantial activity against Trypanosoma cruzi in vitro, in the experimental laboratory and in chronic human Chagas' disease; however, there is no information regarding its action in Chagas' reactivation after heart transplantation. METHODS AND RESULTS: We describe two patients with Chagas' disease who underwent heart transplantation. The first one had asthenia, anorexia, and several painful subcutaneous nodules in the legs after transplantation; biopsy showed an inflammatory infiltrate with intracytoplasmatic nests of Trypanosoma cruzi, confirmed by immunohistochemical stains with monoclonal antibodies specific to parasitic antigens. Allopurinol (600 mg/day) produced complete regression of the symptoms and the nodules with a negative control biopsy within 2 weeks. Treatment was maintained for 2 months. Mild leukopenia developed which improved after azathioprine reduction, and no further side-effects were noted. The second patient had sudden heart failure months after transplantation; endomyocardial biopsy showed myocardial fibers infested with Trypanosoma, and a concomitantly performed right heart catheterization showed a low cardiac index and highfilling pressures. The patient received allopurinol at a daily dose of 900 mg and conventional treatment for heart failure. Echocardiogram showed improved wall motion and decreased left ventricular dimensions, and control biopsy showed no inflammatory activity; cardiac index and filling pressures normalized. Treatment was maintained for 2 months without side effects. The two patients have not had recurrences and were in New York Heart Association functional class I 12 and 3 months, respectively, after discontinuation of allopurinol. CONCLUSIONS: Allopurinol seems to be safe and effective in treating Chagas' disease reactivation after heart transplantation. A larger number of case studies seems to be necessary to properly evaluate its role in the treatment of Chagas' disease reactivation.

Inflammatory response after myocardial revascularization with or without cardiopulmonary bypass.

BACKGROUND: Tumor necrosis factor-alpha has been implicated in complications seen after cardiac operations with cardiopulmonary bypass. The release of tumor necrosis factor-alpha and its possible effects were studied in patients undergoing coronary artery bypass grafting with and without cardiopulmonary bypass. METHODS: Twenty patients were studied, 10 with (group 1) and 10 without cardiopulmonary bypass (group 2). Serial blood samples were obtained before, during, and up to 48 hours after operation. Circulating tumor necrosis factor-alpha levels, leukocyte counts, and erythrocyte sedimentation rates were measured. Hemodynamic variables (blood pressure and heart rate), temperature, orotracheal intubation time, postoperative bleeding, and inotropic drug requirements were compared. RESULTS: Serum levels of tumor necrosis factor-alpha were detected in 6 patients (60%) in group 1 and none in group 2. The patients in group 1 had more hypotension than those in group 2 (7.4 +/- 1.0 mm Hg versus 8.5 +/- 0.7 mm Hg), required more inotropic drugs (8 patients versus 1 patient), and had a higher heart rate (114 +/- 8 beats per minute versus 98 +/- 10 beats per minute), a higher temperature (37.1 degrees +/- 0.5 degrees C versus 36.6 degrees +/- 0.3 degrees C), increased postoperative bleeding (820 +/- 120 mL versus 360 +/- 84 mL), a longer orotracheal intubation time (13.6 +/- 2.2 hours versus 9.3 +/- 1.4 hours), and a more pronounced leukocytosis. CONCLUSIONS: Cardiopulmonary bypass induces the whole-body inflammatory response through the release of tumor necrosis factor alpha, resulting in adverse systemic effects.

ATP reduces blood loss produced by heparin in cardiopulmonary bypass operations.

It was previously shown that topical application of heparin produces enhanced bleeding from small vessels and capillaries. Adenosine triphosphate at low concentrations is able to dislodge heparin bound to a receptor, counteracting its antihemostatic activity. These results led us to measure the amounts of heparin remaining in the blood after protamine neutralization of the patients subjected to cardiopulmonary bypass operation and to test the topical application of the nucleotide. Adenosine triphosphate at a concentration of 10(-4) mol/L significantly reduces the blood volume (p < 0.005) oozed from the thoracic cavity of the patients (mean, 288 +/- 188 mL) when compared with controls (mean, 564 +/- 288 mL). Adenosine triphosphate at 5 x 10(-5) mol/L reduces the blood loss to a mean of 370 +/- 155 mL in the patients tested (p < 0.08). About 10% of heparin of low molecular weight (< or = 6.0 Kda), which is also found in the oozed blood, is not neutralized by protamine. We suggest that the excessive blood loss of the patients is probably produced by low molecular weight heparins in the commercial preparations that are not neutralized by protamine.

Reconstruction of the pulmonary valve and outflow tract with bicuspid prosthesis in tetralogy of Fallot.

BACKGROUND: Right ventricular outflow tract and pulmonary valve implant in patients with tetralogy of Fallot may be required to avoid late postoperative right ventricular impairment. The use of porcine bicuspid prosthesis might be a technical alternative, although comprehensive studies on the long-term use of these prostheses are not available. METHODS: Sixty-three patients (aged 5 months to 34 years; mean, 6 years) with tetralogy of Fallot and pulmonary hypoplasia underwent surgical repair and enlargement of the right ventricular outflow using preserved porcine pulmonary bicuspid prostheses. Fifty-two patients (82.5%) were followed and underwent clinical evaluation and serial Doppler echocardiography. The first 15 patients (29.4%), with ages ranging from 5 to 16 years (mean, 8.2 years) and postoperative follow-up of 48 to 87 months (mean, 65.1 months) underwent hemodynamic and cineangiographic evaluations. RESULTS: There were 11 deaths (17.4%) in the early postoperative period. Of the 52 surviving patients (82.5%), 51 (80.9%) were followed for 1 to 87 months (mean, 42.0 months). Four patients (7.6%) had additional treatment. Of the 15 patients (29.1%) undergoing hemodynamic evaluation, 9 (60%), had mild valvular pulmonary insufficiency and 6 (40%) had moderate insufficiency. Only the right ventricle-to-pulmonary artery pressure gradients and the right ventricular ejection fraction showed statistically significant differences between groups. Right ventricular dimension, although increased in all patients, did not show statistically significant differences. CONCLUSIONS: Right ventricular outflow tract and pulmonary valve repair in patients with tetralogy of Fallot using a bicuspid porcine pulmonary prosthesis is a simple, reliable procedure with good results in postoperative medium term follow-up.

Surgical anatomy of the internal thoracic artery.

BACKGROUND: The internal thoracic artery (ITA) has become increasingly important in coronary artery bypass grafting due to the excellent long-term results. This study reviews its anatomic characteristics. METHODS: The ITAs of 100 cadavers were examined and their origin, relation to the phrenic nerve, presence of lateral costal branch; origin of pericardiacophrenic arteries, length, level and type of ITA termination, relation with the transverse muscle of thorax, collateral parietal branches, and distance between the ITA and sternal margins were studied. RESULTS: The ITA was present in all cases, originating directly from the subclavian artery or from a common trunk with other arteries. Its length was 20.4 cm on average, and the most frequent level of termination was at the sixth intercostal space, existing as a bifurcation in 93% and as a trifurcation in 7%. The pericardiacophrenic artery originated from the ITA in 89%. The lateral costal branch was present in 15% of the cases. The ITA was covered by the transverse muscle of the thorax for 7.5 cm (average) and was crossed anteriorly by the phrenic nerve in 70.0%. CONCLUSIONS: Information provided by this study may contribute to knowledge of its anatomic characteristics and in turn help prevent complications in ITA dissections.

Surgical treatment of acute type B aortic dissection using an endoprosthesis (elephant trunk).

BACKGROUND: The surgical treatment of acute complicated type B aortic dissection continues to be a challenge and is still associated with high morbidity and mortality rates. METHODS: Seventy consecutive patients with an acute type B aortic dissection underwent an elephant trunk procedure through a median sternotomy during deep hypothermic circulatory arrest. An endoprosthesis that was 22 to 24 mm in diameter was inserted through an incision in the arch and held in place with only proximal sutures. RESULTS: The mean arrest time was 31.4 +/- 8.7 minutes, and it was possible to adequately position the endoluminal graft in every patient. The procedure was done in association with other procedures in 13 patients. There were six in-hospital deaths not related to the endoprosthesis, and four late deaths. Late reoperation was necessary in 6 patients to manage leakage at the proximal suture line. CONCLUSIONS: The insertion of an endoprosthesis through the arch for the management of a complicated acute type B dissection has several advantages over the conventional thoracotomy approach. The hospital mortality rate in this series of 70 patients was 20%, and the actuarial 5-year survival rate was 62.5%. We consider the elephant trunk procedure the treatment of choice in patients with type B acute dissections, regardless of whether the dissection is complicated or not.

Successful use of deep hypothermic circulatory arrest in pregnancy.

A woman pregnant for 21 weeks underwent an emergency operation because of an aortic arch aneurysm that had ruptured into her left lung. Cardiopulmonary bypass and deep hypothermia were used and she needed 37 minutes of circulatory arrest at a core temperature of 19 degrees C. Both the mother and fetus survived, and a normal baby was delivered by cesarean section at the 39th week of gestation.

Right heart circulatory support facilities coronary artery bypass without cardiopulmonary bypass.

BACKGROUND: Revascularization of the posterior wall often causes hemodynamic instability in beating heart coronary artery bypass (CAB). Our previous clinical studies have shown that tilting the heart primarily alters right-heart hemodynamics. The purpose of this study was to evaluate right-heart support in clinical cases. METHODS: Seventeen patients underwent beating heart CAB with right-heart support. The right-heart support system (A-Med Systems, West Sacramento, CA) consisted of a coaxial cannula placed through the right atrium and the tip of the cannula positioned in main pulmonary artery. Blood was removed from the right atrium and returned to the main pulmonary artery. RESULTS: Elective beating heart CAB was accomplished successfully in 17 patients with right-heart support. Anastomoses performed were left anterior descending coronary artery (11), diagonal (3), circumflex (5), obtuse marginal artery (11), and right coronary artery (10). Right-heart support between 1 and 3 L/min improved hemodynamics especially in the circumflex position. No device-related patient incidents occurred, nor were there incidents of infection or air embolism. All 17 patients were discharged to their homes. CONCLUSIONS: The right-heart support system was safe without complications. Exposure of the posterior wall was possible in all cases without hemodynamic compromise.

Endomyocardial fibrosis: report of 6 patients and review of the surgical literature.

Six patients with endomyocardial fibrosis were treated by endocardium decortication and atrioventricular valve replacement. There were 5 female patients and 1 male patient ranging from 14 to 48 years old (mean, 30 years). Four patients had involvement of the right ventricle, 1 patient had involvement of the left ventricle, and 1 patient had biventricular disease. There was 1 operative death due to low cardiac output state (the patient with biventricular endomyocardial fibrosis), and there was 1 late noncardiac death. The surgical literature, which describes 19 previously reported cases, was reviewed. On the basis of the results of this series and those of the reported cases, it is concluded that surgical treatment of endomyocardial fibrosis is feasible and provides good clinical improvement.

Endoscopic placement of stents in aneurysms of the descending thoracic aorta.

This is a case of a patient with two saccular aneurysms in the descending aorta. Two self-expanding stents were inserted through an opening in the aortic arch, guided by the use of an Olympus endoscope, under profound hypothermia and total circulatory arrest. The bloodless field made possible the identification of the main thoracic branches, facilitating the positioning and deployment of both stents. Immediate postoperative recovery was excellent.

Replacement of infected thoracic aortic prosthesis with a spiral composite vein graft.

We describe a case of a patient who had a ruptured aorta repaired by femorofemoral bypass with an interposition graft and subsequently had a graft infection. The patient was taken to operation and the old graft was removed. It was replaced by a spiral great saphenous vein graft. The patient has been followed up for 36 months with computed tomographic scanning, which has shown that the vein graft has not dilated.

Coronary artery bypass grafting without cardiopulmonary bypass.

BACKGROUND: Coronary artery bypass grafting without cardiopulmonary bypass is now an accepted technique of myocardial revascularization. We herein report our total experience with this procedure. METHODS: In a consecutive series of 8,751 patients operated on in our institution for coronary artery disease from 1981 to 1994, 1,274 patients received coronary artery bypass grafting without cardiopulmonary bypass. RESULTS: Results indicate that the operation can be performed with an acceptable mortality (2.5%), and that all types of arterial conduits can be used. Most commonly the left anterior descending and right coronary arteries were bypassed. The incidence of arrhythmias and of pulmonary and neurologic complications were significantly lower in this group of patients compared with patients receiving coronary artery bypass grafting with cardiopulmonary bypass. Most importantly, there was decreased cost when the procedure was used because no extracorporeal circulation, cardioplegia sets, or other cannulas were used. CONCLUSIONS: We conclude that the continuing use of coronary artery bypass grafting without cardiopulmonary bypass is justified and that, with proper selection of patients, the procedure is safe and cost-effective.

Importance of intraoperative transesophageal echocardiography during coronary artery surgery without cardiopulmonary bypass.

The goal of this study was to assess left ventricular segmental wall motion (SWM) abnormalities during coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB), and its impact on the immediate postoperative outcome. Transesophageal echocardiography was used intraoperatively in 27 patients (mean age 57 years) who had CABG without CPB. Images obtained with a 5-MHz biplane transesophageal echocardiographic probe in the transgastric and transesophageal planes were recorded before, during, and after 48 coronary artery clampings for saphenous vein or internal mammary artery anastomosis. Transthoracic echocardiography was performed 1 day before surgery and on the seventh postoperative day. During the 48 coronary artery clampings, 31 (64%) new SWM abnormalities were found. At the time of chest closure, complete recovery occurred in 16 (50%) segments, partial recovery in 10 (33%), and no recovery in 5 (17%). On the seventh postoperative day the new SWM abnormalities persisted in all 5 segments without recovery at the end of the surgery and in 2 of 10 (20%)segments with partial recovery (group 1). Group 1 had higher variation on the echocardiographic point score index between the beginning and end of surgery, higher enzymatic levels, more ST-T changes on the electrocardiogram, and more clinical problems than group 2 (patients without new SWM abnormalities on the seventh postoperative day) (P < .05). We concluded that new SWM abnormalities of the left ventricle occur during CABG without CPB as assessed by intraoperative transesophageal echocardiography. Persistence of these abnormalities at the end of surgery may be a predictor of SWM dysfunction and clinical problems in the immediate postoperative period.

Coronary artery bypass grafting without cardiopulmonary bypass through sternotomy and minimally invasive procedure.

Coronary artery bypass grafting without cardiopulmonary bypass (CPB) is now an accepted technique of myocardial revascularization in a special subset of patients. This paper presents our total experience in 1761 cases operated on since September 1981 until April 1997 out of a total of 9164 patients revascularized with the conventional technique during this period of time. Among the 1761 patients, 53 (3%) were operated on by minimally invasive surgery. The overall applicability was 19.2% and the most common grafted arteries were left anterior descending artery (LAD), right coronary artery (RCA), and diagonal. Results indicate that the operation can be performed with an acceptable mortality (2.3%) and that all types of arterial conduits can be used. The incidence of major postoperative complications were significantly lower in this group of patients when compared with our patients receiving conventional myocardial revascularization. Most importantly there was decrease cost when the procedure was used because no extracorporeal circulation cardioplegia sets or other cannulas were used. We conclude based on in this fifteen years experience that the technique of myocardial revascularization in a beating heart is justified, safe and can offer to selected patients the best option of coronary insufficiency surgical treatment.

A juvenile sheep model for the long-term evaluation of stentless bioprostheses implanted as aortic root replacements.

BACKGROUND AND AIM OF THE STUDY: Orthotopic valve replacement in large animals is an important component of the preclinical assessment of bioprosthetic valves. To provide the most useful preclinical information, the development of models that parallel clinical practice patterns is essential. Therefore, we sought to develop a technically feasible and reproducible model for chronic evaluation of stentless bioprosthetic aortic valves implanted as aortic root replacements in juvenile sheep. METHODS: Juvenile domestic sheep (mean age 21+/-2.28 weeks; range: 17-26 weeks) underwent aortic root replacement using standard cardiopulmonary bypass (CPB) and surgical techniques. Animals were implanted with 19 mm (n = 21), 21 mm (n = 18) or 23 mm (n = 4) bioprostheses from two different manufacturers, and followed for 150 days. Animals surviving at least 150 days were considered long-term survivors; those which died prior to postoperative day (POD) 31 were considered operative deaths. RESULTS: Forty-three animals underwent aortic root replacement. The mean CPB time was 91+/-20 min (range: 62-149 min); mean cross-clamp time was 63+/-13 min (range: 39-95 min). Thirty-five animals (81%) survived the first 30 days of the study period. Five deaths occurred at POD 0 due to anastomotic complications. One death occurred each on POD 3, 6, and 26 as a result of prosthesis size mismatching, thromboembolic complications, and endocarditis, respectively. There were five late deaths. Twenty animals survived the minimum 150-day study period, and 12 were sacrificed at 183+/-17 days. Six animals remain alive at 151+/-0.98 days, and one animal died each on POD 184 and 190. The remaining 10 animals are not yet 150 days from their operation. Currently, all are well at 102+/-34 days (range: 33-140) days. CONCLUSION: These data suggest that long-term evaluation of stentless aortic bioprostheses implanted as aortic root replacements can be accomplished using juvenile sheep.

Surgical retrieval of undeployed intracoronary stent without cardiopulmonary bypass.

Intracoronary stenting has now become a widely established method for treatment of complications of coronary angioplasty. The risk of stent embolism exists and if not retrieved, it may lead to thrombosis and coronary occlusion with myocardial infarction. We report a case of embolism of an undeployed intracoronary stent where there was failure of percutaneous attempts to pull back the stent, requiring surgical retrieval and simultaneous coronary artery bypass grafting, both without cardiopulmonary bypass.

Mitral valve replacement with glutaraldehyde preserved aortic allografts.

OBJECTIVE: To present long-term results after mitral valve replacement with stent mounted glutaraldehyde preserved aortic allografts in patients older than 15 years. The clinical support for this study was to combine the glutaraldehyde technique of biological tissue preservation with the advantages of allografts when compared to xenografts. This was demonstrated in previous studies using other methods of tissue processing. METHODS: Between September 1984 and November 1994, 70 patients aged 16-77 years (mean 35.4 years) underwent mitral valve replacement with this preserved and mounted allograft. Of these, 40 patients (57.2%) were aged 16-35 years and 15 (21.4%) were 20 years old or younger; 46 (65.7%) were females and 24 (34.3%) males. Single mitral valve replacement was performed in 60 patients and 10 were also subjected to other combined cardiac procedures. Human aortic valves were obtained during routine autopsy, processed in glutaraldehyde and mounted into flexible stents, using the same technique as that used for porcine bioprostheses. RESULTS: Hospital mortality was 1.4%. Total follow-up was 543.1 patient-years, corresponding to a mean follow-up of 7.9 years per patient. Echocardiography demonstrated a hemodynamic performance similar to porcine bioprostheses. Late mortality was 0.7 +/- 0.6% per patient-year and the causes were congestive heart failure in 2, prosthetic endocarditis in 1 and acute myocardial infarction in 1. The 12-year actuarial survival was 92.4 +/- 3.2%. The incidence of late complications was 5.2 +/- 1.2% per patient-year, including congestive heart failure, prosthetic endocarditis, periprosthetic leak, thromboembolic episodes, recurrence of rheumatic disease, coronary artery disease and allograft failure. Complications related to heart disease represented 2.8 +/- 0.6% and allobioprosthesis-related 2.4 +/- 0.5% per patient-year. The 12-year actuarial freedom from primary valve failure was 81.0 +/- 15.0%. The incidence of reoperations was 1.5 +/- 0.8% per patient-year and the main indication was prosthetic endocarditis. Other causes were periprosthetic leak, aortic insufficiency in the native aortic valve and allobioprosthesis dysfunction. Functional results demonstrated a significant improvement in patients clinical condition. CONCLUSION: This 12-year follow-up shows a very low incidence of primary allograft failure for patients older than 15 years undergoing mitral valve replacement, and much superior than our results with porcine bioprosthesis in the same age group. This supports our assumption that this investigational valve represents a new advance in cardiac valve surgery.