Walter J. Gomes

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.

On-pump versus off-pump coronary revascularization: evaluation of renal function

BACKGROUND Coronary revascularization with cardiopulmonary bypass has the potential risk of renal dysfunction related to the nonphysiologic nature of cardiopulmonary bypass. Recently, there has been a revival of interest in performing myocardial revascularization on the beating heart and we investigated whether this prevents renal compromise. METHODS A prospective, randomized, controlled trial was performed in 50 patients (45 males, mean age 61+/-3.7 years) undergoing elective coronary artery bypass grafting. Patients were randomly assigned to conventional revascularization with cardiopulmonary bypass (on pump) or beating heart revascularization (off pump). Glomerular and tubular function were assessed up to 48 hours postoperatively. RESULTS There were no deaths, myocardial infarctions or acute renal failure in either group. Glomerular filtration as assessed by creatinine clearance and the urinary microalbumin/creatinine ratio was significantly worse in the on pump group (p < 0.0004 and 0.0083, respectively). Renal tubular function was also impaired in the on pump group as assessed by increased N-acetyl glucosaminidase activity (p < 0.0272). CONCLUSIONS These results suggest that off pump coronary revascularization offers a superior renal protection when compared with conventional coronary revascularization with cardiopulmonary bypass and cardioplegic arrest in first time coronary bypass patients.

Beating versus arrested heart revascularization: evaluation of myocardial function in a prospective randomized study

OBJECTIVE Conventional coronary artery bypass grafting (CABG) is both safe and effective. Nevertheless, the use of cardiopulmonary bypass (CPB) and cardioplegic arrest are associated with several adverse effects. Over the last 2 years there has been a revival of interest in performing CABG on the beating heart. In this prospective randomized study we evaluated the efficacy and safety of on and off pump coronary revascularization on myocardial function. METHODS Eighty patients (65 males, mean age 61+/-9.7 years) undergoing first time CABG were prospectively randomized to: (i) conventional revascularization with CPB at normothermia and cardioplegic arrest with intermittent warm blood cardioplegia (on pump) or (ii) beating heart revascularization (off pump). Troponin I (Tn I) release was serially measured as a specific marker of myocardial damage. Haemodynamic measurements as well as inotropic requirement, incidence of arrhythmia and postoperative myocardial infarction were also recorded. RESULTS There were no significant differences between the two groups in terms of age, sex, extent of disease, left ventricular function and number of grafts. There were no deaths or intraoperative myocardial infarctions in either group. Tn I release was constantly lower in the off pump group and this was significant at 1, 4, 12 and 24 h postoperatively. Furthermore, in this group there was a significantly reduced incidence of arrhythmias. Inotropic requirements were less in the off pump group but this did not reach statistical significance. CONCLUSION These results suggest that off pump coronary revascularization is a safe and effective strategy for myocardial revascularization. Myocardial injury as assessed by Tn I release is also reduced when compared with conventional coronary revascularization with CPB and cardioplegic arrest.

Efeitos do local de inserção do dreno pleural na função pulmonar no pós-operatório de cirurgia de revascularização do miocárdio

OBJECTIVE: To analyze the pulmonary function changes and pain in patients undergoing off-pump coronary artery bypass grafting utilizing a left internal thoracic artery graft, comparing the pleural drain insertion through the intercostal space and subxyphoid approach. METHODS: Twenty eight patients (mean age 57.4 ± 8.4 years) were divided into two groups, according to the pleural drain site. Group IL (n=15) had the pleural drain inserted through the sixth left intercostal space at the mid-axillary line and in the IM group (n=13) the drain was placed through the subxyphoid region. All the patients underwent pre- and post-operative evaluation of pulmonary function tests as well as arterial blood gas analysis. Forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) were recorded in the preoperative period, and in the first, third and fifth postoperative days. The pain sensation was evaluated using a standard score from 0 to 10. RESULTS: In both groups falls in FVC and FEV1 were noted, up to the fifth postoperative day (P<0.001). However, the decrease was higher in the IL group, when compared to the IM group (p<0.05). Also arterial blood gas analysis showed a decline of the partial oxygen pressure in both groups on the fist postoperative day, but more significantly in the IL group (p=0.021). The pain sensation was higher in the IL group (p=0.002). CONCLUSION: Off-pump coronary artery bypass grafting with using of left internal thoracic artery, disregarding the pleural drain site, leads to a significant decrease of postoperative pulmonary function. However, the subxyphoid technique of drain insertion has shown a better preservation of the lung function when compared to the intercostal drain site.

Evaluation of pulmonary function in patients following on and off-pump coronary artery bypass grafting

OBJECTIVE: To evaluate and compare the pulmonary function in patients following on- and off-pump coronary artery bypass grafting (CABG). METHOD: Thirty patients (mean age 56.76 ± 10.20 years) were allocated to two groups, according to the use or not of cardiopulmonary bypasses: group A (n=15) off-pump and group B (n=15) on-pump, with all patients undergoing pre- and post-operative evaluation of the pulmonary function as well as arterial blood gases analysis. Forced vital capacity (FVC) and forced expiratory volume at 1 second (FEV1) were recorded in the preoperative period, and on the first, third and fifth postoperative days. Blood gases were evaluated in the preoperative period and on the first postoperative day. RESULTS: In both groups, significant falls in the FVC and FEV1 were detected up to the fifth postoperative day (p<0.05). When both groups were compared, the decreases in FCV and VEF1 were higher in group B (p<0.05). PaO2 values and the PaO2/FiO2 ratio presented significant drops on the first postoperative day in both groups, however the fall was higher in group B (p<0.05). CONCLUSION: Patients who undergo CABG, regardless of the use of CPB, display a significant reduction in the postoperative pulmonary function. However, patients who undergo off-pump CABG have a better preservation of the lung function compared to on-pump CABG.

Síndrome da resposta inflamatória sistêmica na circulação extracorpórea: papel das interleucinas

The systemic inflammatory response syndrome (SIRS) occurs in the cardiac surgery more often with the use of CPB. It is due to the contact of the blood with non-endothelial surfaces and, later to reperfusion. This contact leads to the release of substances such as anaphylotoxins, which are activated by the complement factor, and stimulate the production of pro-inflammatory cytokines (IL-1, IL-6, TNF-a). Cytokines are responsible for induction of fever, neutrophilia with increase of adhesiveness between neutrophils and mocytes and, they act synergetically stimulating the production of other interleukins (IL-6, IL-8). It is observed that intestinal ischemia secondary to CPB, causes the production of IL-6, TNF-a, IL-1 in the intestinal epithelium and, reperfusion post CPB induces the expression of IL-1 and TNF-a in the vascular endothelium that can generate a dysfunction able to injure cardiomyocytes. Following the post-CPB cascade of reactions, the adult respiratory distress syndrome is mediated by IL-8, found the at alveolar level. The brain and the liver can also be affected by ischemia/reperfusion phenomena and, once more, it is shown that interleukins (IL-8 and IL-13, respectively) have an important role in the course of SIRS- related events. CPB and anesthesia techniques can influence interleukin activity. There is not a consensus regarding preventive or treatment therapies for complications from SIRS. Possible choices are: intervention at the level of inflammation mediators, digestive decontamination procedures, use of drugs such as indometacin or steroids. The regulation of the inflammatory process, generally depends on the balance between anti- and pro- inflammatory cytokines. These later are detectable in normal individuals whereas the others only manifest locally or are almost inexistent. We conclude that the increase of the concentration of pro-inflammatory interleukins in the organism is expected during important surgical intervention. Such an increase will bring complications if it is exacerbated and, the organism is debilitated.

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.

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.

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.

Emergency repair of Type A aortic dissection in Type IV Ehlers-Danlos Syndrome

Ehlers-Danlos syndrome type IV is a distinctive syndrome in which thin and fragile skin, premature ageing, bruising and scarring are combined with lethal or life-threatening arterial weakness. Aortic rupture either at the aortic root and arch, or sometimes lower down the artery, are particularly characteristic. Even quite minor injury can produce dangerous vascular tearing and damage. Technical difficulties encountered in arterial repair or venous ligature are particularly worrying. The authors report the treatment of a ruptured type A aortic dissection associated with Ehlers-Danlos syndrome where the extreme fragility of the tissues and tendency to bleed posed a difficult task for the surgeon.