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.

Anomalous left coronary artery from pulmonary artery: autogenous arterial tube for aortic implantation

Many surgical procedures for the implantation of anomalous left coronary artery from pulmonary artery have been described. A dual coronary system offers most benefit and is most advantageous for the patient. Two autogenous flaps of the pulmonary trunk and ascending aorta, without mobilizing the coronary artery, were created for use in this procedure. This technique was successfully used in an 8 month-old patient with severe myocardial dysfunction and moderate mitral regurgitation. This procedure allows 2 coronary systems to be repaired for any anatomic change of the left coronary artery without the use of prosthetic material. There were no technical complications. During the postoperative course minimal inotropic support was used. The magnetic resonance study, 11 months postoperative, showed wood flow of the left coronary artery and mild mitral regurgitation. The operative technique was simple and its execution easy. The follow-up in the intermediate and late period showed the growth of this endothelized tube.

Expression of inducible nitric oxide synthase is increased in patients with heart failure due to ischemic disease

The objective of the present study was to determine the relationship between nitric oxide synthases (NOS) and heart failure in cardiac tissue from patients with and without cardiac decompensation. Right atrial tissue was excised from patients with coronary artery disease (CAD) and left ventricular ejection fraction (LVEF) <35% (N = 10), and from patients with CAD and LVEF >60% (N = 10) during cardiac surgery. NOS activity was measured by the conversion of L-[H(3)]-arginine to L-[H(3)]-citrulline. Gene expression was quantified by the competitive reverse transcription-polymerase chain reaction. Both endothelial NOS (eNOS) activity and expression were significantly reduced in failing hearts compared to non-failing hearts: 0.36 +/- 0.18 vs 1.51 +/- 0.31 pmol mg-1 min-1 (P < 0.0001) and 0.37 +/- 0.08 vs 0.78 +/- 0.09 relative cDNA absorbance at 320 nm (P < 0.0001), respectively. In contrast, inducible NOS (iNOS) activity and expression were significantly higher in failing hearts than in non-failing hearts: 4.00 +/- 0.90 vs 1.54 +/- 0.65 pmol mg-1 min-1 (P < 0.0001) and 2.19 +/- 0.27 vs 1.43 +/- 0.13 cDNA absorbance at 320 nm (P < 0.0001), respectively. We conclude that heart failure down-regulates both eNOS activity and expression in cardiac tissue from patients with LVEF <35%. In contrast, iNOS activity and expression are increased in failing hearts and may represent an alternative mechanism for nitric oxide production in heart failure due to ischemic disease.

A multicenter initial clinical experience with right heart support and beating heart coronary surgery

BACKGROUND

During coronary surgery without CPB, exposure of posterior vessel via sternotomy can cause deterioration of cardiac hemodynamics requiring inotrope drugs support. Recent animal experiments demonstrate hemodynamic benefit of right heart support (RHS) with the AMED system. The purpose of this study was to evaluate the hemodynamic effects during cardiac manipulation to expose the posterior coronary arteries, and determine the effect of RHS in restoring hemodynamics, increasing anastomotic exposure and reducing inotropic requirements.

MATERIAL AND METHODS

From July 28 to December 29, 32 patients (25 men/7 women), mean age of 63.4 (+/- 6.2 years, ages: 49-78) received coronary revascularization with the A-Med RHS device. They were divided into two groups of 16 patients, A and B. Group A patients had at least one circumflex branch bypassed. The anterior wall was systematically bypassed off-pump without RHS. The right coronary artery (RCA) and the obtuse coronary artery (OM) were completed utilizing RHS. In group B patients, all vessels including anterior vessels were bypassed with the RHS. Mean arterial pressure (MAP), mean pulmonary arterial pressure (PAP), cardiac output (CO) and the average pump flow (APF) were recorded during the OM and RCA bypass for group A, and for group B LAD data was also recorded.

RESULTS

Elective beating heart coronary artery bypass graft (CABG) was successfully accomplished in 32 patients with RHS. Data measurements recorded in Group A showed the improved hemodynamic recovery for OM and RCA bypass with RHS. The MAP increased from 44 to 68 mmHg (OM) and from 63 to 81 mmHg (RCA); the CO from 2.1 to 4.4 L/min (OM) and from 3.3 to 4.7 L/min (RCA). In group B, the data recorded showed the stability of the MAP in all vessels bypassed (LAD, OM and RCA). No device-related patient incidents occurred. All 32 patients were discharged to their homes.

CONCLUSIONS

The AMED system, as RHS support, facilitated coronary bypass without CPB to posterior vessels, restoring hemodynamics, providing better exposure to anastomotic sites and apparently reducing inotropes need. Prospective randomize trials are necessary to confirm this initial experience.

Conventional and conventional plus modified ultrafiltration during cardiac surgery in high-risk congenital heart disease

BACKGROUND

This prospective nonrandomized study is the critical assessment of conventional ultrafiltration (CUF) and modified ultrafiltration (MUF) techniques and their efficiency in congenital heart disease surgeries. Use of cardiopulmonary bypass (CPB) in children is associated with body water retention as a consequence of prime volume and systemic inflammatory reaction. The CUF during CPB has reduced body water excess and the MUF after CPB, removes inflammatory mediators, improves hemodynamic performance, and decreases transfusion requirements.

METHODS

Forty-one patients, aged 9 to 36 months, submitted to surgical correction for cardiac defects, using CPB, were divided into 2 similar groups: CUF (21 patients) operated between 1996-1997 were ultrafiltered during CPB, and CUF+MUF, (20 patients) operated between 1997-1998 and ultrafiltered during and after CPB. Postoperative duration of ventilator support, pediatric intensive care unit stay (PICU), hospital stay of the groups with and without preoperative pulmonary hypertension (PH), as well as transfusion requirement, hematocrit and platelet counts were compared.

RESULTS

There were no technical complications and a significant ultrafiltrate in the CUF+MUF group was observed as compared to the CUF group. No significant differences were observed between the CUF and CUF+MUF groups regarding ventilatory support, PICU stay and hospital stay. Requirements for red cell transfusion, Ht and platelet counts were not statistically different.

CONCLUSIONS

CUF and CUF+MUF were safe and efficient methods for patient stabilization independent of diagnosis and complexity of surgery. Future clinical evaluation should address a larger population of patients to research the different variables.

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.

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.

Is the number of microembolic signals related to neurologic outcome in coronary bypass surgery?

Coronary artery bypass surgery (CABG) without cardiopulmonary bypass (CPB) may potentially reduce the number of microembolic signals (MES) associated with aortic manipulation or generated by the pump circuit, resulting in a better neurologic outcome after surgery. Our aim was to compare the frequency of MES and neurologic complications in CABG with and without CPB. Twenty patients eligible to routine CABG without CPB were randomized to surgery with CPB and without CPB and continuously monitored by transcranial Doppler. Neurologic examination was performed in all patients before and after surgery. The two groups were similar with respect to demographics, risk factors, grade of aortic atheromatous disease and number of grafts. The frequency of MES in the nonCPB group was considerably lower than in CPB patients, however, we did not observe any change in the neurologic examination during the early postoperative period. Neurologic complications after CABG may be related to the size and composition of MES rather than to their absolute numbers. A large prospective multicentric randomized trial may help to elucidate this complex issue.

Arterial wall damage caused by snaring of the coronary arteries during off-pump revascularization

BACKGROUND

Anastomosis of a saphenous or mammary artery conduit to the coronary artery requires precise and reproducible microsurgical technique. Over the past 3 decades, the elective induction of cardiac arrest and circulatory support have provided the conditions suitable for microsurgical anastomosis to all coronary vessels. Beating heart coronary grafting was rejuvenated at our center in 1985 as an alternative to cardiopulmonary bypass and cardioplegic arrest. One of the requirements for off-pump grafting is local vascular control of the target vessel and prevention of bleeding into the field from the open coronary artery. The most common hemostasis technique in use today is the application of circumferential traction sutures and snares around the coronary artery. We performed a human cadaver study to evaluate the potential for local trauma to the native coronary artery caused by this method of hemostasis.

METHODS

Our research team applied both 5-0 polypropylene and 2-0 polyester snares to the proximal and distal right coronary artery (RCA) and left anterior descending (LAD) in 25 isolated fresh human cadaver hearts. A total of 100 points of snare application to the native coronary vessels were induced and then investigated histologically, with hematoxylin-eosin, Weigert, and phosphotungstic hematoxylin staining.

RESULTS

The results suggested a direct relationship between the severity of the arterial lesion induced by the snares and the degree of local atherosclerotic disease in the native coronary artery. Compression and buckling of the elastic lamellae with medial fractures (similar in nature to angioplasty but directed inward) were seen when snares were applied to a region with marked atherosclerotic disease.

CONCLUSIONS

The application of snares to the coronary artery proximal and distal to the anastomotic site must be done with caution. In cases of marked atherosclerotic disease in the underlying coronary artery, a new intimal-medial lesion can occur with indiscriminate application of a tourniquet. This phenomenon may account for some of the reported cases of late peri-anastomotic or distal stenoses seen with off-pump coronary artery bypass grafting and significantly detract from the advantages offered by beating heart surgery. If one or both snares can be avoided entirely, or applied carefully to disease-free segments of the vessel, this problem may be avoided entirely.

Cytokines and pediatric open heart surgery with cardiopulmonary bypass

It is well known that, subsequent to cardiopulmonary bypass, and particularly in children, an inflammatory response within the body can often result in a characteristic syndrome. Recently, it has been suggested that this phenomenon is due to a systemic inflammatory response, with significant involvement of cytokines. With this in mind, we investigated the behavior of tumour necrosis factor-alpha and interleukin-6 during the operative and in the immediate postoperative period in a group of children submitted to open heart surgery. We investigated any possible relation between the levels of these cytokines in the serum and the length of cardiopulmonary bypass, with the serum levels of lactate, and with the extent of use of inotropic drugs in postoperative period. The cytokines were measured in samples withdrawn after induction of anesthesia, after 10 minutes of cardiopulmonary bypass, after re-establishment of circulation, and then 2 and 24 hours after the end of cardiopulmonary bypass. The levels of tumour necrosis factor-alpha and interleukin-6 increased between the beginning and at two hours of the end of cardiopulmonary bypass. There was no correlation between the levels of these cytokines in the serum and the length of cardiopulmonary bypass, although there was a positive relation between levels of interleukin-6 and lactate in samples withdrawn at two hours of the end of bypass, and the measured levels of the cytokines correlated with the extent of inotropic drugs employed in the postoperative period.

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.

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.

A new surgical approach for treating dilated cardiomyopathy with mitral regurgitation

OBJECTIVE

To evaluate the early outcome of mitral valve prostheses implantation and left ventricular remodeling in 23 patients with end-stage cardiomyopathy and secondary mitral regurgitation (NYHA class III and IV).

METHODS

Mitral valvular prosthesis implantation with preservation of papillary muscles and chordae tendinae, and plasty of anteriun cuspid for remodeling of the left ventricle.

RESULTS

The surgery was performed in 23 patients, preoperative ejection fraction (echocardiography) varied from 13% to 44% (median: 30%). In 13 patients associated procedures were performed: myocardial revascularization (9), left ventricle plicature repair (3) and aortic prosthesis implantation (1). Early deaths (2) occurred on the 4th PO day (cardiogenic shock) and on the 20th PO day (upper gastrointestinal bleeding), and a late death in the second month PO (ventricular arrhythmia). Improvement occurred in NYHA class in 82. 6% of the patients (P<0.0001), with a survival rate of 86.9% (mean of 8.9 months of follow-up).

CONCLUSION

This technique offers a promising therapeutic alternative for the treatment of patients in refractory heart failure with cardiomyopathy and secondary mitral regurgitation.

Video-endoscopic dissection of multiple pedicled arterial grafts for use in minimally invasive coronary artery bypass surgery

BACKGROUND

We evaluated the possibility of video-endoscopic dissection of both internal thoracic arteries (rTAs) through the left thoracic approach and right gastroepiploic artery (GEA) via a small laparoscopic access, for use in minimally invasive coronary artery bypass surgery.

METHODS

The procedure was performed on twenty-two mongrel dogs. Three 10 mm ports were inserted in the left hemithorax to enable the introduction of a rigid 0-degree videoscope and forceps which allowed access to the left and right ITAs. For dissection of the GEA, one 10 mm and two 5 mm ports were inserted in the para-umbilical region.

RESULTS

The left and right ITAs and the GEA were easily visualized and dissection and complete mobilization was achieved without injury, which was checked by the presence of good blood flow. The ITAs and GEA were divided distally, exteriorized through a small left anterior thoracotomy and the length of these three grafts were able to reach all of the left coronary artery branches.

CONCLUSIONS

We have demonstrated, in dogs, the feasibility of video-assisted dissection of both the left and right ITAs through the left thoracic approach, without sternotomy, avoiding the risks of sternal complications and expanding its use for all patients. Furthermore, a third arterial conduit (the RGA) can be used without requiring laparotomy.

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.

Vasoplegic syndrome after open heart surgery

BACKGROUND

A new form of postperfusion manifestation is detailed, a vasoplegic syndrome presenting in the postoperative period after cardiopulmonary bypass (CPB) heart surgery.

METHODS

This retrospective study included sixteen patients who underwent cardiovascular surgery using CPB and exhibited clinical and hemodynamic features compatible with vasoplegic syndrome. The technique of CPB was hypothermic (28 degrees C) in 15 and normothermic in 1 patient, and hypothermic blood cardioplegia was employed in all patients, except 1. The mean CPB time was 121 minutes, ranging from 80 to 210 minutes.

RESULTS

The patients presented a severe feature comprising hypotension, tachycardia, normal or elevated cardiac output, low systemic vascular resistance and decreased filling pressures. Fluid administration alone was not capable of restoring hemodynamic parameters. Physical examination revealed normal capillary filling at the extremities although oliguria and hypotension were observed. These patients needed a high dosage of vasoconstrictor drugs (norepinephrine) for blood pressure control but even high dose norepinephrine did not produce the classical situation of cool extremities and weak peripheral pulses, with increased morbidity and mortality. Severe systemic complications could develop if the vasoplegic syndrome persisted 36-48 hours after its onset. All patients, except 3, presented associated postoperative complications and 4 patients died. The characteristics of vasoplegic syndrome are similar to those observed in septic shock, where the alterations are mediated by cytokines and tumor necrosis factor-alpha.

CONCLUSIONS

The appearance of vasoplegic syndrome augmented operative morbidity with a consequent increased risk to the patient in the early postoperative period.

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.

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.

[Utilization of self-expandable prosthesis (stent) introduced through the femoral artery for treatment of dissection of the descending aorta]

PURPOSE

We present four cases of dissection of the thoracic descending aorta that underwent treatment with an auto expandable dácron-covered stent.

METHODS

The stent was deployed through the femoral artery in the hemodynamic laboratory after sedation, local anesthesia in both inguinal areas and systemic heparinization. The catheter with the stent was introduced through a cutdown in the left femoral artery until the area in the thoracic aorta with the previously diagnosed tear.

RESULTS

The stent was expanded with immediate occlusion of the false lumen. The whole procedure took 90 minutes and the patients were discharged without complications.

CONCLUSION

Stent utilization is an important step to improve treatment results in type B aortic dissection.

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.

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.

Anatomical and clinical aspects of the blood supply of the sinoatrial node

BACKGROUND

The recent study of the variations of the origin of the sinoatrial node and on the "arterial network of the perinodal sinusal area" in normal hearts points out the importance of this network.

PURPOSE

Report on a case of patient with syncope of ischemic etiology.

CONCLUSION

In this patient the arterial network did not protect the node from the ischemia caused by the obstruction of the artery of the sinoatrial node.

[Cardiorespiratory response during exercise in heart transplant recipients. Comparative ergoespirometric analysis with normal health subjects]

PURPOSE

To evaluate the cardiorespiratory response of heart transplant (HT) recipients.

METHODS

Nine HT recipients (GI) underwent ergospirometric tests and were compared to 9 apparently healthy, sedentary subjects with similar sex, age, weight and height (GII). All were male patients aging 48 +/- 12 years, in functional class I (NYHA) an average of 23 +/- 21 months after HT. They were receiving cyclosporin, azathioprine, prednisone, dipyridamole and antihypertensive drugs. The tests were symptom-limited and they were interrupted due to exhaustion.

RESULTS

During peak exercise, GI had a significantly lower physical performance related to lower VO2, VE, VEO2, HR, endurance time and work load. At the anaerobic threshold, VO2, endurance time and work load levels were also significantly lower in GI. The physical performance was similar between the groups in the 40W load.

CONCLUSION

The cardiorespiratory performance in GI was significantly lower at peak exercise and similar to GII in the 40W load, showing the HT benefits cardiac patients during usual activities.

[Hemostatic changes in children treated with heart surgery with cardiopulmonary bypass]

PURPOSE

We evaluated hemostasic changes in children undergoing open heart surgery with cardiopulmonary bypass (CPB).

METHODS

We studied 17 children before, during surgery, in the immediate, first and between the 4th and 7th postoperative days, measuring hematocrit, prothrombin time, activated partial thromboplastin time, fibrinogen, platelet count, factor V and euglobulin lysis time. Children were divided in those with and without excessive bleeding in the postoperative period.

RESULTS

We observed significant prolongation of prothrombin time and activated partial thromboplastin time, reduction of fibrinogen and factor V, and shortening of euglobulin lysis time. Six (35%) children bled excessively. Platelet count reduction was greater in the intra operative period in these cases and the duration of CPB was longer in this group.

CONCLUSION

Changes in hemostasis during open heart surgery are due to coagulation cascade disorders as well as fibrinolysis. The incidence of excessive bleeding is higher in the pediatric group. Prolonged CPB time and greater reduction in platelet count differentiated both groups.

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.

[Assessment of left internal thoracic artery anastomosis with left anterior descending coronary artery by Doppler echocardiography]

PURPOSE

To study the value of Doppler echocardiography as a tool for the evaluation of left internal thoracic artery graft (LITAG) patency in patients who underwent coronary revascularization using minimally invasive bypass surgery without extracorporeal circulation.

METHODS

The first 12 consecutive patients were studied after coronary artery bypass surgery using a 5 MHz Doppler transducer. Doppler signals for the systolic and diastolic flow velocities were preferably obtained in the second intercostal space. All patients underwent coronary angiography while hospitalized.

RESULTS

The exam was feasible in 93% of patients. Doppler flow pattern was predominantly diastolic (pattern A) in patients with patent anastomoses (6/7). In patients with occluded anastomoses (4/4) Doppler flow pattern was predominantly systolic (pattern B) (p = 0.003).

CONCLUSION

Internal thoracic artery flow pattern as measured by Doppler echocardiography after minimally invasive coronary artery bypass graft surgery is an accurate method for identifying LITAG patency.

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.

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.

[Myocardial revascularization through small left anterior minithoracotomy]

PURPOSE

To analyze the results of myocardial revascularization through small left anterior thoracotomy utilizing the left thoracic internal artery (LTIA) to left anterior descending coronary artery (LAD) without cardiopulmonary bypass, in order to simplify the operative procedure.

METHODS

From September/95 till August/96 we operated on 45 patients with lesions in LAD or LAD and diagonal arteries that were revascularized with an anastomoses of the LTIA to LAD or LAD and diagonal as composite grafts, through left anterior small thoracotomy. In the second postoperative day 43 out of 45 patients were restudied with arteriography and/or transthoracic echocardiography that showed excellent patency in 39 of them.

RESULTS

Six patients with obstruction or stenoses were reoperated through median sternotomy without complications. We did not observe flow through intercostal arteries in these restudies except in cases of obstructed anastomosis, showing that it is not necessary to ligate these branches. We observed too, excellent correlation between angiographic patterns and diastolic flows detected in the thoracic internal artery with transthoracic echocardiography.

CONCLUSION

These initial results suggest that this approach may be good to a subset of patients with lesions in LAD and/or diagonal arteries and if associated with complementary angioplasties of other coronary arteries may be the best choice of invasive treatment of coronary insufficiency in a near future.

[Heart surgery in Brazilian Indians]

PURPOSE

Our experience with surgical treatment of heart diseases in Indians living in the Amazon rain forest in primitive stages was reviewed.

METHODS

From 1988 to 1995, 18 patients underwent cardiovascular surgical procedures at the São Paulo Hospital of the Escola Paulista de Medicina. Seven patients had valvar disease, nine congenital heart defects, one submitral aneurysm and one arrhythmia. Thirteen Indians came from tribes of the Amazon rain forest area: three from the Xavante, two from Waiapi, two from Tucano, two from Macuxi, two from Mayoruna, and one of each tribe of Xikrin, Guajajara, Terena, Surui, Galibi, Cinta-Larga and Pataxó.

RESULTS

We performed 22 operations, with two hospital deaths. Follow-up was possible in 87.5% of cases, with one late death. The majority of cases were due to congenital heart defects and in this series it was noted the absence of operations to treat coronary artery disease. The incidence of valve disease was higher in accultured or semi-accultured Indians.

CONCLUSION

The surgical treatment of cardiovascular disease has made possible to the surviving indians to return to and be accepted by their fellow tribesmen.

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.

Transaortic approach has a role in the surgical treatment of ventricular septal defects

A transaortic approach was used for surgical closure of ventricular septal defects (VSDs), sometimes as first choice and otherwise as an alternative approach. This paper presents the experience in a group of 124 patients who underwent VSD closure by a transaortic approach in an 18-year-period, between 1974 and 1992. Patients were divided in three groups: (I) Isolated VSD, 89 patients (mean age 7.6 years); (II) VSD associated with other malformations, 27 patients (mean age 10.8 years); and (III) recurrent VSD, eight patients (mean age 15.6 years). Two deaths occurred in the postoperative period (2/124), one after closure of VSD in a patient with severe pulmonary hypertension; another death was observed after transaortic closure of the VSD as part of the repair of a complex heart malformation. There were no instances of new right bundle branch block (RBBB) in the group operated on for isolated VSDs. Three cases of left bundle branch block (LBBB) (3.4%) occurred in the isolated VSD group. There were no cases of complete aortic valve (AV) block in the whole series and no instances of AV dysfunction. The transaortic approach is an alternative for the surgical treatment of ventricular septal defects. The ease of exposure and closure of defects suggest this technique to be a particularly attractive approach in the treatment of small to moderate-sized VSDs and also in recurrent VSDs.

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.

[Pregnancy after heart transplantation]

A 25-year old female patient, with peripartum cardiomyopathy was submitted to heart transplantation and became pregnant two years after. Pregnancy was uneventful and a baby-girl was born completely healthy. Six years after pregnancy, the mother remains well with preserved ventricular function and the girl has had a normal development. Although considered a high-risk situation and not indicated, pregnancy after heart transplantation is possible, without any apparent deterioration of the transplanted graft and with healthy babies being delivered.

Neurological outcome in coronary artery surgery with and without cardiopulmonary bypass

INTRODUCTION

The neurological complications of coronary artery surgery with cardiopulmonary bypass (CPB) have been extensively studied, but to our knowledge those without CPB (NCPB) have not been defined.

PATIENTS & METHODS

We prospectively examined 81 patients, before and up to seven days after surgery, to compare the neurological morbidity between patients subjected to coronary artery bypass graft (CABG) surgery with and without CPB. We analyzed demographic variables, risk factors and neurological examination including neuropsychological (NPS) tests using chi-square and non-parametric analysis (Mann-Whitney and Kruskal-Wallis).

RESULTS

Forty-eight patients (34M; median age = 62 yrs; median number of grafts = 3 and median total surgery duration = 300 min) operated with CPB and 33 without CPB (23M; median age = 64 yrs; median number of grafts = 2 and median total surgery duration = 240 min) differed only in relation to number of grafts (p = 0.0001) and surgery duration (p = 0.0001).

CONCLUSION

We found no difference in early neurological outcome in patients subjected to CABG with or without CPB.

[Heart surgery with extracorporeal circulation in pregnant women. Analysis of materno-fetal outcome]

PURPOSE

To analyze maternal and fetal outcome in pregnant undergone to cardiac surgery.

METHODS

We studied the evolution of 30 pregnant women submitted to cardiac surgery at the Hospital São Paulo, between Jan/81 and Dec/92 and, further, attended at this Hospital till the parturition. The following variables were analyzed: cardiopulmonary bypass, time of the procedure and time of the anoxia, patient temperature, surgical complications, and neonatal, maternal and fetal outcomes.

RESULTS

All patients had rheumatic heart disease and, in 17, mitral stenosis was the main anatomic abnormality. Mitral commissurotomy was performed in 24 patients, double comissurotomy (mitral and aortic) in 1 patient and valve replacement was performed in 5. Cardiopulmonary bypass was utilized in all procedure; occurrence of surgical complications (p < 0.001) and the prolonged surgical time (p = 0.009) were related to the fetal mortality. There was 4 (13.3%) maternal deaths and 10 (33.3%) fetal deaths related to the surgery.

CONCLUSION

The indication of cardiac surgery in pregnant women is heart failure, refractory to conventional therapy; cardiopulmonary bypass is associated with high fetal mortality.

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.

[Prolonged respiratory support with extracorporeal membrane oxygenation in lung transplantation]

A 42 year-old woman with terminal chronic lung disease underwent to left lung transplantation. Extracorporeal membrane oxigenation (ECMO) was required because dysfunction of transplanted organ occurred and was non-responsive to conventional therapy. The time of assistance was 47 hours and after this, the dysfunction of the transplanted lung reversed and the patient was weaned from the oxigenator. During hospital stay, she developed sepsis and died. In conclusion, ECMO was decisive to the treatment of pulmonary dysfunction, allowing time to the resolution of lung lesion.

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.

[Myocardial revascularization without extracorporeal circulation. Surgical results in 1090 patients]

PURPOSE

To report our experience of 12 years of myocardial revascularization without cardiopulmonary bypass (CPB) and to discuss its expanding surgical indications.

METHODS

This technique was employed in 1090 patients, between September/81 and April/93, corresponding to 17.4% of all revascularized patients. Regarding gender, male patients were the majority (73.7%) and ages ranged from 28 to 86 year-old (mean 57). Chronic coronary insufficiency was the main indication (69.4%) and 18.9% of our global experience were operated on during acute ischemia. The average number of grafts per patient was 1.6 and internal mammary artery was utilized in 60.1% of patients. Left anterior descending coronary artery and right coronary artery were the coronary arteries most often treated.

RESULTS

Our hospital mortality rate was 2.5% (28/1090) although it was 7% for patients over 70 years. The most common cause of death was cardiogenic shock after failed angioplasty. Postoperative complications included AMI in 4.8%, arrhythmias in 5.5% and pulmonary in 3.2%. Mean of any type of blood derivate utilization was 0.28 units/patients.

CONCLUSION

Myocardial revascularization without CPB is a valid alternative in a selected cohort of patients and it is performed with low morbidity and mortality. Nowadays it represents an excellent tactical option for high-risk patients and in failed angioplasties.